ORCID Profile
0000-0002-2982-0411
Current Organisation
University of Western Australia
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Crop and Pasture Improvement (Selection and Breeding) | Quantitative Genetics (incl. Disease and Trait Mapping Genetics) | Crop and Pasture Production | Crop and Pasture Biochemistry and Physiology
Environmentally Sustainable Plant Production not elsewhere classified | Climate Change Adaptation Measures | Canola |
Publisher: Oxford University Press (OUP)
Date: 23-10-2010
DOI: 10.1093/JXB/ERP307
Publisher: Wiley
Date: 04-2004
Publisher: Elsevier BV
Date: 1972
Publisher: Elsevier BV
Date: 10-2019
Publisher: CSIRO Publishing
Date: 1992
DOI: 10.1071/EA9920797
Abstract: Duplex or texture-contrast soils occur over about 60% of the agricultural areas of south-west Western Australia. Annual crops of wheat, barley, oats, and lupins predominate on these soils, grown in rotation with annual pastures. The climate is characterised by cool, wet winters and hot, dry summers. Crop production is restricted to the winter and spring and is limited by waterlogging in the wet winter months and by water shortage during grain filling in spring. Research on crop production on duplex soils has been undertaken for the past 8 years by a collaborative team from the CSIRO Dryland Crops andyoils Program and the Western Australian Department of Agriculture. This research has been focussed on 3 sites at which processes limiting crop production on duplex soils have been highlighted. This special issue was initiated to summarise that research and to put it in its regional and national perspective. Additionally, opportunity was taken to compare and contrast experiences both within Western Australia and throughout Australia, and to draw out management options for crop production on duplex soils.
Publisher: Elsevier BV
Date: 09-2002
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/AR03122
Abstract: The yields of wheat and canola in 2 successive years with and without the development of a perched watertable were compared in the high rainfall zone of south-western Australia. In 2001, no perched watertable was observed and wheat and canola yields were close to their estimated potentials. In 2002, a perched watertable developed at less than 30 cm below the soil surface for more than 8 days and at less than 50 cm below the soil surface for at least 30 days at the tillering stage of wheat and at the rosette stage of canola. The air-filled porosity of the soil fell below the critical value of 10% at 10 and 30 cm depth for about 40 days. This reduced the maximum leaf area index of canola by 46% and of wheat by 30%, and reduced the shoot dry matter of wheat at flowering by 27% and by 40% at podding in canola compared with those in 2001. The growth of the wheat roots was constrained at depths from 50-90 cm from the soil surface in 2002 compared with 2001. However, the roots of canola and wheat were able to grow to at least 1.4 m in both 2001 and 2002. In both years, a much higher proportion ( %) of roots was present in the clay subsoil compared with previous reports in south-western Australia and enabled the crops to utilise a greater amount of water from the clay subsoil. The wheat yield in 2002 was 37% lower than in 2001 and well below the potential, largely as a result of a reduced tiller number per plant and ears per unit area. Despite the greater reduction in dry matter in canola than in wheat in 2002, the seed yield of canola was 17% higher in 2002 than in 2001. Canola, an indeterminate crop, was able to respond to the late rain that occurred in 2002 compared with 2001 and produced a significantly higher seed number per unit area. In 2002, grain size in wheat was 25% larger than in 2001, but this increase was insufficient to compensate for the yield loss resulting from the fewer ears per unit area. It is concluded that early transient perched watertable induced subsurface waterlogging, and that the subsurface waterlogging can be a major constraint to crop growth in the high rainfall region of southwestern Australia, and that reducing waterlogging could be a key to achieving higher crop production.
Publisher: Oxford University Press (OUP)
Date: 08-2007
DOI: 10.1603/0022-0493(2007)100[1416:BAIITP]2.0.CO;2
Abstract: This glasshouse study used an improved larval measurement procedure to evaluate the impact of transgenic pea, Pisum sativum L., seeds expressing a-amylase inhibitor (AI)-1 or -2 proteins on pea weevil, Bruchus pisorum L. Seeds of transgenic 'Laura' and 'Greenfeast' peas expressing alpha-(AI)-1 reduced pea weevil survival by 93-98%. Larval mortality occurred at an early instar. Conversely, in nontransgenic cultivars, approximately 98-99% of the pea weevils emerged as adults. By measuring the head capsule size, we determined that larvae died at the first to early third instar in alpha-(AI)-1 transgenic peas, indicating that this inhibitor is highly effective in controlling this insect. By contrast, transgenic Laura and 'Dundale' expressing alpha-(AI)-2 did not affect pea weevil survival, but they did delay larval development. After 77 d of development, the head capsule size indicated that the larvae were still at the third instar stage in transgenic alpha-(AI)-2 peas, whereas adult bruchids had developed in the nontransgenic peas.
Publisher: Springer Science and Business Media LLC
Date: 28-03-2015
Publisher: Springer Science and Business Media LLC
Date: 18-03-2012
Publisher: Wiley
Date: 09-2012
Publisher: Elsevier BV
Date: 2017
Publisher: Springer Science and Business Media LLC
Date: 07-09-2011
Publisher: Elsevier BV
Date: 10-2013
Publisher: Springer Science and Business Media LLC
Date: 05-1986
DOI: 10.1007/BF00377619
Publisher: Elsevier BV
Date: 1986
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/CP17028
Abstract: Drought and heat stress are two major constraints that limit chickpea (Cicer arietinum L.) yield, particularly during seed filling. The present study aimed (i) to assess the in idual and combined effects of drought and heat stress on oxidative metabolism during seed filling, and (ii) to determine any genetic variation in oxidative metabolism among genotypes differing in drought and heat tolerance and sensitivity. The plants were raised in outdoor conditions with two different times of sowing, one in November (normal-sown, temperatures °C−20°C (day–night) during seed filling), and the other in February (late-sown, temperatures °C−20°C (day–night) during seed filling). Plants were regularly irrigated to prevent any water shortage until the water treatments were applied. At both sowing times, the drought treatment was applied during seed filling (at ~75% podding) by withholding water from half of the pots until the relative leaf water content (RLWC) of leaves on the top three branches reached 42–45%, whereas leaves in the fully irrigated control plants were maintained at RLWC 85–90%. Drought-stressed plants were then rewatered and maintained under fully irrigated conditions until maturity. Several biochemical parameters were measured on the leaves and seeds at the end of the stress treatments, and seed yield and aboveground biomass were measured at maturity. In idual and combined stresses damaged membranes, and decreased PSII function and leaf chlorophyll content, more so under the combined stress treatment. The levels of oxidative molecules (malondialdehyde (MDA) and H2O2) markedly increased compared with the control plants in all stress treatments, especially across genotypes in the combined heat + drought stress treatment (increases in leaves: MDA 5.4–8.4-fold and H2O2 5.1–7.1-fold in seeds: MDA 1.9–3.3-fold and H2O2 3.8–7.9-fold). The enzymatic and non-enzymatic antioxidants related to oxidative metabolism increased under in idual stress treatments but decreased in the combined heat + drought stress treatment. Leaves had higher oxidative damage than seeds, and this likely inhibited their photosynthetic efficiency. Yields were reduced more by drought stress than by heat stress, with the lowest yields in the combined heat + drought stress treatment. Heat- and drought-tolerant genotypes suffered less damage and had higher yields than the heat- and drought-sensitive genotypes under the in idual and combined stress treatments, suggesting partial cross-tolerance in these genotypes. A drought-tolerant genotype ICC8950 produced more seed yield under the combined heat + drought stress than other genotypes, and this was associated with low oxidative damage in leaves and seeds.
Publisher: Copernicus GmbH
Date: 28-01-2016
Abstract: Abstract. Soil organic carbon (SOC) plays a vital role as both a sink for and source of atmospheric carbon. Revegetation of degraded arable land in China is expected to increase soil carbon sequestration, but the role of perennial legumes on soil carbon stocks in semiarid areas has not been quantified. In this study, we assessed the effect of alfalfa (Medicago sativa L.) and two locally adapted forage legumes, bush clover (Lespedeza davurica S.) and milk vetch (Astragalus adsurgens Pall.) on the SOC concentration and SOC stock accumulated annually over a 2 m soil profile. The results showed that the concentration of SOC in the bare soil decreased slightly over the 7 years, while 7 years of legume growth substantially increased the concentration of SOC over the 0–2.0 m soil depth. Over the 7-year growth period the SOC stocks increased by 24.1, 19.9 and 14.6 Mg C ha−1 under the alfalfa, bush clover and milk vetch stands, respectively, and decreased by 4.2 Mg C ha−1 in the bare soil. The sequestration of SOC in the 1–2 m depth of the soil accounted for 79, 68 and 74 % of the SOC sequestered in the 2 m deep soil profile under alfalfa, bush clover and milk vetch, respectively. Conversion of arable land to perennial legume pasture resulted in a significant increase in SOC, particularly at soil depths below 1 m.
Publisher: Oxford University Press (OUP)
Date: 1983
Publisher: Springer Science and Business Media LLC
Date: 12-11-2019
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/AR04104
Abstract: Chickpea (Cicer arietinum L.) genotypes comprising released cultivars, advanced breeding lines, and landraces of Australian, Mediterranean basin, Indian, and Ethiopian origin were evaluated at 5 representative sites (Merredin, WA Minnipa, SA Walpeup, Vic. Tamworth, NSW Warwick, Qld) over 2 years. Data on plant stand, early vigour, phenology, productivity, and yield components were collected at each site. Site yields ranged from 0.3 t/ha at Minnipa in 1999 to 3.5 t/ha at Warwick in 1999. Genotype by environment (G × E) interaction was highly significant. Principal components analysis revealed contrasting genotype interaction behaviour at dry, low-yielding sites (Minnipa 1999, Merredin 2000) and higher rainfall, longer growing-season environments (Tamworth 2000). Genotype clusters performing well under stress tended to yield well at all sites except Tamworth in 2000, and were characterised by early phenology and high harvest index, but were not different in terms of biomass or early vigour. Some of these traits were strongly influenced by germplasm origin. The material with earliest phenology came from Ethiopia, and southern and central India, with progressively later material from northern India and Australia, and finally the Mediterranean. There was a delay between the onset of flowering and podding at all sites, which was related to average temperatures immediately post-anthesis (r = –0.81), and therefore larger in early flowering material ( days at some sites). Harvest index was highest in Indian and Ethiopian germplasm, whereas crop height was greatest in Australian and Mediterranean accessions. Some consistently high yielding genotypes new to the Australian breeding program were identified (ICCV 10, BG 362), and the existing cultivar Lasseter was also confirmed to be very productive.
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/AR03135
Abstract: With a view to identifying and understanding the genotypic differences in yield under terminal drought, a range of lupin genotypes representing narrow-leafed lupin (Lupinus angustifolius L.) and yellow lupin (Lupinus luteus L.) was studied in field experiments in the low rainfall Mediterranean environment of Western Australia over 3 seasons. In each year Merrit, the most common commercial cultivar in Western Australia, was used as the reference to which the yield of other genotypes was compared. In the first and third year, 5 or 6 genotypes were grown with and without irrigation from the start of pod set. In the second year, 9 genotypes were grown with irrigation and under a rainout shelter from the start of pod set. Detailed measurements were made of plant water status, leaf area and biomass production, flowering and podding date, and seed yield and its components.The timing and intensity of the terminal drought varied from average in 1998 and 1999 to extreme in 2000. Post-podding leaf water potential (Ψleaf) under rainfed conditions decreased to –2 MPa in 1998 and 1999 and below –2.5 MPa in 2000, whereas under supplementary irrigation it was maintained at –1.2 MPa in 1998 and 1999 and at –1.5 MPa in 2002.The seed yield of all genotypes under terminal drought varied from 24 to 66% of that with supplementary irrigation. In each year, the seed yield under rainfed conditions showed genotypic differences consistent with the timing and intensity of the development of terminal drought. Under conditions of terminal drought the seed yields of the narrow-leafed lupin cultivars Belara and Tallerack, and of the breeding line WALAN 2049, were higher than of Merrit by 29% in 1998. Tanjil, Belara, and Quilinock out-yielded Merrit by 33–53% in 1999 and Belara and Quilinock out-yielded Merrit by 80% in 2000. Harvest index was higher in Belara and Quilinock than in Merrit. Under both terminal drought conditions and supplemental irrigation, Belara and Quilinock had high seed yields that were associated with a greater number of seeds per pod and larger seed size. It is argued that early flowering and podding in Belara and Quilinock allowed more seeds to develop and fill before the terminal drought became more severe.
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/FP14135
Abstract: The reproductive phase of chickpea (Cicer arietinum L.) is more sensitive to water deficits than the vegetative phase. The characteristics that confer drought tolerance to genotypes at the reproductive stage are not well understood especially which characteristics are responsible for differences in seed yield under water stress. In two consecutive years, 10 genotypes with contrasting yields under terminal drought stress in the field were exposed to a gradual, but similar, water stress in the glasshouse. Flower number, flower + pod + seed abortion percentage, pod number, pod weight, seed number, seed yield, 100-seed weight (seed size), stem + leaf weight and harvest index (HI) were recorded in well watered plants (WW) and in water-stressed plants (WS) when the level of deficit was mild (phase I), and when the stress was severe (phase II). The WS treatment reduced seed yield, seed and pod number, but not flower + pod + seed abortion percentage or 100-seed weight. Although there were significant differences in total seed yield among the genotypes, the ranking of the seed yield in the glasshouse differed from the ranking in the field, indicating large genotype × environment interaction. Genetic variation for seed yield and seed yield components was observed in the WW treatment, which also showed differences across years, as well as in the WS treatment in both the years, so that the relative seed yield and relative yield components (ratio of values under WS to those under WW) were used as measures of drought tolerance. Relative total seed yield was positively associated with relative total flower number (R2 = 0.23 in year 2) and relative total seed number (R2 = 0.83, R2 = 0.79 in years 1 and 2 respectively). In phase I (mild stress), relative yield of seed produced in that phase was found to be associated with the flower number in both the years (R2 = 0.69, R2 = 0.76 respectively). Therefore, the controlled drought imposition that was used, where daily water loss from the soil was made equal for all plants, revealed genotypic differences in the sensitivity of the reproductive process to drought. Under these conditions, the seed yield differences in chickpea were largely related to the capacity to produce a large number of flowers and to set seeds, especially in the early phase of drought stress when the degree of water deficit was mild.
Publisher: Wiley
Date: 18-05-2023
DOI: 10.1002/TPG2.20343
Abstract: Drought is a major constraint for wheat production that is receiving increased attention due to global climate change. This study conducted isobaric tags for relative and absolute quantitation proteomic analysis on near‐isogenic lines to shed light on the underlying mechanism of qDSI.4B.1 quantitative trait loci (QTL) on the short arm of chromosome 4B conferring drought tolerance in wheat. Comparing tolerant with susceptible isolines, 41 differentially expressed proteins were identified to be responsible for drought tolerance with a p ‐value of 0.05 and fold change .3 or .7. These proteins were mainly enriched in hydrogen peroxide metabolic activity, reactive oxygen species metabolic activity, photosynthetic activity, intracellular protein transport, cellular macromolecule localization, and response to oxidative stress. Prediction of protein interactions and pathways analysis revealed the interaction between transcription, translation, protein export, photosynthesis, and carbohydrate metabolism as the most important pathways responsible for drought tolerance. The five proteins, including 30S ribosomal protein S15, SRP54 domain‐containing protein, auxin‐repressed protein, serine hydroxymethyltransferase, and an uncharacterized protein with encoding genes on 4BS, were suggested as candidate proteins responsible for drought tolerance in qDSI.4B.1 QTL. The gene coding SRP54 protein was also one of the differentially expressed genes in our previous transcriptomic study.
Publisher: Oxford University Press (OUP)
Date: 10-09-2004
DOI: 10.1093/JXB/ERH154
Publisher: Oxford University Press (OUP)
Date: 12-01-2004
DOI: 10.1093/JXB/ERH037
Publisher: Springer Science and Business Media LLC
Date: 02-03-2011
Publisher: Elsevier BV
Date: 04-1991
Publisher: Springer Science and Business Media LLC
Date: 17-06-2012
Publisher: Oxford University Press (OUP)
Date: 06-11-2007
DOI: 10.1093/JXB/ERL192
Abstract: Variation in osmotic adjustment (OA) among chickpea (Cicer arietinum L.) cultivars has been observed when exposed to terminal drought, but some studies suggest that this benefits yield while others suggest it does not benefit yield in water-limited environments. In the present study, parents differing in OA were crossed and a set of advanced breeding lines (ABLs) developed for yield testing. The variation in OA during podding was measured under terminal drought in the F(2), F(3), F(7), and F(8) progeny and in the parents by either rehydrating the leaves before s ling for osmotic potential (OP) or by measuring the relative water content (RWC) and OP on adjacent leaves for the calculation of the OP at full turgor. Yields were measured in the F(8) progeny under terminal drought in Australia and India. While differences in OA were measured in the chickpea lines and parents, OA varied from year to year and did not consistently benefit yield when measured in the field under terminal drought. In Australia, differences in OA were not associated with any yield benefit in any year, while in India early flowering resulted in higher yields at three of the four sites, and OA had an inconsistent effect on seed yields. A comparison of OP at full turgor measured after rehydration and from measurements of RWC and OP showed that the rehydration technique underestimated OA. The lack of contribution of OA to yield of chickpea is discussed.
Publisher: Wiley
Date: 28-12-2021
DOI: 10.1002/CSC2.20677
Abstract: Plastic‐film mulch significantly improves maize ( Zea mays L.) productivity in hydrothermally limited areas, but there is a lack of understanding of how mulch affects the partitioning of dry matter and nutrients to grain. This study was conducted to investigate the effects of plastic‐film mulch on the remobilization of biomass and nutrients accumulated in the presilking stage to grain during the grain‐filling period. A 2‐yr field experiment was conducted with five maize hybrids in a cold semiarid environment. The vegetative biomass in all cultivars at maturity was generally greater than that at silking regardless of whether the soil was mulched or not, indicating that there was no translocation of presilking assimilates to the grain. The increased grain yield in plastic‐film mulched plots compared with those that were nonmulched was ascribed to their enhanced partitioning of postsilking assimilates to grain. Conversely, increased accumulation of nitrogen and phosphorus in grain at maturity under mulch relative to no mulch mainly was due to increased remobilization from presilking vegetative organs. The benefit of plastic‐film mulch in increasing the partitioning of postsilking assimilates and the remobilization of nutrients from presilking vegetative organs was greater in a drier than in a wetter year. The results of this study strongly support the conclusion that in hydrothermally limited environments, maize generally does not remobilize presilking assimilates but does remobilize presilking nitrogen and phosphorus in vegetative organs to the grain during grain filling. Further, plastic‐film mulched, relative to nonmulched, maize increases the translocation to the grain of postsilking assimilates and presilking nitrogen and phosphorus accumulated in vegetative organs.
Publisher: Springer Science and Business Media LLC
Date: 03-01-2012
Publisher: Oxford University Press (OUP)
Date: 2001
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/CPV62N6_ED
Publisher: Wiley
Date: 11-10-2013
Publisher: Elsevier BV
Date: 02-2022
Publisher: Wiley
Date: 08-1982
Publisher: Elsevier
Date: 2017
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/CP08440
Abstract: Tiller production and survival are suppressed on soils prone to waterlogging. The tiller production and growth of wheat (Triticum aestivum cv. Wyalkatchem) was investigated in a glasshouse experiment during and after a transient waterlogging to examine its effect on grain yield. Wheat plants received either a high or low nitrogen (N) application at sowing and were waterlogged at 22 days after sowing for 14 days. Plants received a second either high or low N application after waterlogging was released. Waterlogging induced a transient N deficiency. The N concentration of the youngest expanded leaf on the mainstem and tillers declined markedly during waterlogging, but its recovery 14 days after the waterlogging was ended was independent of treatment, reaching a greater than the critical minimum concentration of 3.5%. The growth of primary tillers 1 and 2 was severely inhibited by waterlogging while the exsertion of new tillers was delayed by 9 days. Shoot dry weight of the waterlogged plants at final harvest was reduced by 37% compared with the non-waterlogged plants. During the recovery period, the waterlogged plants produced higher order tillers that produced late ears. As a result, the number of ears per plant was similar in plants in continuously drained or previously waterlogged soil. Waterlogging reduced the number of grains per ear on the mainstem and tillers, and consequently grain yield by 32%. High N application after waterlogging increased grain yield by ~20%, but high N applied at sowing had no effect on yield. This suggests that N application after waterlogging can reduce the detrimental effect of waterlogging on grain yields in areas prone to waterlogging.
Publisher: Springer Science and Business Media LLC
Date: 02-1981
DOI: 10.1007/BF02180062
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/AR05089
Abstract: Chickpea (Cicer arietinum) developed as a post-rainy season, spring-sown crop early in its evolution and spread into warm subtropical regions, in contrast to its wild relatives that have remained as winter annuals in West and Central Asia. To test whether these different life cycles selected for different phenological strategies in wild and cultivated Cicer, germplasm from a wide range of habitats was subjected to different cold treatments (vernalisation, control) at germination, and phenology evaluated at warm and cool field sites (14.8–15.1°C and 13.1°C, respectively). All wild Cicer species, except for C. yamashitae, responded positively to vernalisation and accelerated the dates of flowering, podding, and maturity. There was no vernalisation response in cultivated chickpea, whereas C. arietinum/C. echinospermum and C. arietinum/C. reticulatum interspecific hybrids were intermediate, flowering 6–16 days earlier after vernalisation. Relative podding dates differed between sites. Chickpea podded earlier than most vernalised wild species under warm conditions, but not at the cool site. Regression against post-anthesis temperature showed that the delay in podding was consistent with a lack of cold tolerance in the cultigen. The interspecific hybrids were significantly more cold tolerant than chickpea, and the wild species were almost insensitive to the temperature range recorded at the cool site. Vernalisation responsiveness and a greater tolerance of low temperatures during the reproductive phase demonstrate that the annual wild Cicer species harbour important traits that can be used to widen adaptation in the cultigen, and may help to improve the performance of chickpea as a Mediterranean cool-season crop.
Publisher: Oxford University Press (OUP)
Date: 26-10-2016
DOI: 10.1104/PP.16.01313
Publisher: Elsevier
Date: 2014
Publisher: Wiley
Date: 07-1984
Publisher: Elsevier BV
Date: 1986
Publisher: Wiley
Date: 06-1978
Publisher: Wiley
Date: 10-1981
Publisher: Oxford University Press (OUP)
Date: 25-03-2009
Abstract: The contrasting hydraulic properties of wheat (Triticum aestivum), narrow-leafed lupin (Lupinus angustifolius), and yellow lupin (Lupinus luteus) roots were identified by integrating measurements of water flow across different structural levels of organization with anatomy and modeling. Anatomy played a major role in root hydraulics, influencing axial conductance (L ax) and the distribution of water uptake along the root, with a more localized role for aquaporins (AQPs). Lupin roots had greater L ax than wheat roots, due to greater xylem development. L ax and root hydraulic conductance (L r) were related to each other, such that both variables increased with distance from the root tip in lupin roots. L ax and L r were constant with distance from the tip in wheat roots. Despite these contrasting behaviors, the hydraulic conductivity of root cells (Lp c) was similar for all species and increased from the root surface toward the endodermis. Lp c was largely controlled by AQPs, as demonstrated by dramatic reductions in Lp c by the AQP blocker mercury. Modeling the root as a series of concentric, cylindrical membranes, and the inhibition of AQP activity at the root level, indicated that water flow in lupin roots occurred primarily through the apoplast, without crossing membranes and without the involvement of AQPs. In contrast, water flow across wheat roots crossed mercury-sensitive AQPs in the endodermis, which significantly influenced L r. This study demonstrates the importance of examining root morphology and anatomy in assessing the role of AQPs in root hydraulics.
Publisher: Wiley
Date: 05-2000
Publisher: Springer Science and Business Media LLC
Date: 02-1972
DOI: 10.1038/235341A0
Publisher: Springer Science and Business Media LLC
Date: 02-1981
DOI: 10.1007/BF02180051
Publisher: Elsevier BV
Date: 04-2012
Publisher: Oxford University Press (OUP)
Date: 08-2012
DOI: 10.1093/JXB/ERS164
Publisher: Oxford University Press (OUP)
Date: 1994
DOI: 10.1093/JXB/45.7.909
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/CP15078
Abstract: Climate change is predicted to decrease crop yields in semi-arid and subtropical regions of the world and this could negatively affect smallholder farmers in the developing world. Previous analysis has suggested that with low fertiliser input, yields of sorghum increased as temperatures increased. We used the wide range of tropical environments in the small mountainous island country of Timor-Leste to evaluate the impact of global warming on maize (Zea mays) yields with (i) no fertiliser input and (ii) increased nitrogen (N) supply. We calibrated the well-tested APSIM-Maize model for the cultivar of maize grown throughout Timor-Leste. We simulated maize yields at four locations with 8 years of reliable weather records, at present temperatures, +1.5°C and +3.0°C, with 0, 40 and 80 kg/ha of added N, with 1.2, 1.9 and 3.8% soil organic carbon (SOC), and with increased duration of the vegetative phase. With no added N, higher temperatures increased yields at the cooler, higher elevation sites and decreased yields at the warmest site near the coast. With fertiliser application, warming temperatures decreased yields or induced no change in simulated yield at all locations. Simulations with three levels of N supply for the four sites, which differed in temperature, showed a strong temperature × N supply interaction on yield. At maximum growing-season temperatures °C, yields decreased with increasing temperature at all levels of fertilisation. At maximum growing-season temperatures of 23−31°C, yields increased with increasing temperature with no added fertiliser, were unchanged with the application of 40 kg N/ha, and decreased with increasing temperatures with application of 80 kg/ha N. The changes in yield with temperature and N supply were associated with N uptake by the maize, which showed the same interaction with maximum temperature and N added. SOC acted as a source of N, so that changes in yield induced by temperature and N were similar whether the N was from an organic or an inorganic source. Increasing the duration of the vegetative phase resulted in lower or no change in yields at all sites. We conclude that global warming will increase the yield for low-input smallholder farmers growing maize at maximum growing-season temperatures °C, but that micro-dosing with N will increase yields at all locations with mean maximum temperatures of 20−35°C.
Publisher: Elsevier BV
Date: 09-1976
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/AR05225
Abstract: An experiment was conducted under controlled conditions in a glasshouse to determine the sensitivity of reproductive development of lentil (Lens culinaris Medikus) genotypes of different origins to water deficit. The 3 genotypes were Cassab (West Asia), Simal (South Asia), and ILL 7979 a crossbred between a West Asian genotype and a South Asian genotype. Two watering treatments, a well-watered control and a water-deficit treatment, were imposed from the beginning of podding. Leaf water relations, total dry matter production, leaf area, and number of flowers, pods, and seeds were measured from podding to maturity. In the well-watered plants the leaf water potential (ψleaf) before sunrise ranged from −0.6 to −0.8 MPa. When subjected to water deficit, ψleaf fell to about −3.0 MPa. Genotypes did not show variation in vegetative growth or seed yield under either well-watered or water-deficit conditions, but they differed significantly in the number of flowers, fruiting nodes, pods, and seeds, and harvest index (HI). Seed size in Cassab was 61% larger than ILL 7979 and 105% larger than Simal. The small-seeded genotypes produced the highest number of fruiting nodes and hence a greater number of flowers, pods, and seeds. Seed size was positively correlated with seed growth rate (r = 0.77**) and seed fill duration (r = 0.45*). The water deficit reduced plant height by about 20%, leaf area by 48–81%, and total dry matter by about 60% compared with well-watered plants. The water deficit reduced flower number by 35–46% and increased seed abortion (empty pods) by 17–46%. The water deficit had no effect on the maximum seed growth rate, seed fill duration, or final seed size in any of the 3 genotypes. Therefore, the 70% reduction in seed yield induced by the water deficit was primarily due to a reduction in pod and seed numbers (by 59–70%) rather than in idual seed growth rate and seed size.
Publisher: American Chemical Society (ACS)
Date: 29-06-2015
Abstract: Grass pea (Lathyrus sativus L.) cultivation is limited because of the presence in seeds and tissues of the nonprotein amino acid β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP), a neurotoxin that can cause lathyrism in humans. Seven grass pea genotypes differing in seed β-ODAP concentration were grown in pots at three levels of water availability to follow changes in the concentration and amount of β-ODAP in leaves and pods and seeds. The concentration and amount of β-ODAP decreased in leaves in early reproductive development and in pods as they matured, while water stress increased β-ODAP concentration in leaves and pods at these stages. The net amount of β-ODAP in leaves and pods at early podding was positively associated with seed β-ODAP concentration at maturity. We conclude that variation among genotypes in seed β-ODAP concentration results from variation in net accumulation of β-ODAP in leaves and pods during vegetative and early reproductive development.
Publisher: Elsevier BV
Date: 09-2013
Publisher: Elsevier
Date: 1996
Publisher: Springer Science and Business Media LLC
Date: 04-06-2015
Publisher: Elsevier BV
Date: 02-2018
Publisher: Elsevier BV
Date: 10-2013
Publisher: Wiley
Date: 05-01-2011
Publisher: Institute of Experimental Botany
Date: 12-2011
Publisher: Elsevier BV
Date: 08-2012
Publisher: Wiley
Date: 04-01-2011
Publisher: Wiley
Date: 30-10-2012
DOI: 10.1111/GFS.12010
Publisher: Elsevier BV
Date: 07-2009
Publisher: Elsevier BV
Date: 03-2017
Publisher: Oxford University Press (OUP)
Date: 23-02-2021
Abstract: Abscisic acid (ABA) can induce rapid stomatal closure in seed plants, but the action of this hormone on the stomata of fern and lycophyte species remains equivocal. Here, ABA-induced stomatal closure, signaling components, guard cell K+ and Ca2+ fluxes, vacuolar and actin cytoskeleton dynamics, and the permeability coefficient of guard cell protoplasts (Pf) were analyzed in species spanning the ersity of vascular land plants including 11 seed plants, 6 ferns, and 1 lycophyte. We found that all 11 seed plants exhibited ABA-induced stomatal closure, but the fern and lycophyte species did not. ABA-induced hydrogen peroxide elevation was observed in all species, but the signaling pathway downstream of nitric oxide production, including ion channel activation, was only observed in seed plants. In the angiosperm faba bean (Vicia faba), ABA application caused large vacuolar compartments to disaggregate, actin filaments to disintegrate into short fragments and Pf to increase. None of these changes was observed in the guard cells of the fern Matteuccia struthiopteris and lycophyte Selaginella moellendorffii treated with ABA, but a hypertonic osmotic solution did induce stomatal closure in fern and the lycophyte. Our results suggest that there is a major difference in the regulation of stomata between the fern and lycophyte plants and the seed plants. Importantly, these findings have uncovered the physiological and biophysical mechanisms that may have been responsible for the evolution of a stomatal response to ABA in the earliest seed plants.
Publisher: Springer Science and Business Media LLC
Date: 2001
Publisher: Frontiers Media SA
Date: 29-03-2022
Abstract: The workflow of this study. (1) Near isogenic lines for qDSI.4B.1 QTL responsible for drought tolerance were grown in control and drought stress conditions, (2) grain s les were collected at 7 and 14 days after stress initiation at anthesis, (3) RNA was extracted, (4) sequenced and (5) data were analysed and organized with focus on 4BS, (6) six candidate genes were found for drought tolerance in qDSI.4B.1 interval and sequencing results were confirmed by qRT-PCR, (7) the protein products and (8) molecular function of the candidate genes were future studied.
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/FP14057
Abstract: The objective of the InterDrought conferences is to be a platform for debating key issues that are relevant for increasing the yield and yield stability of crops under drought via integrated approaches. InterDrought-IV, held in Perth, Australia, in September 2013, followed previous InterDrought conferences in bringing together researchers in agronomy, soil science, modelling, physiology, biochemistry, molecular biology, genetics and plant breeding. Key themes were (i) maximising water productivity (ii) maximising dryland crop production (iii) adaptation to water-limited environments (iv) plant productivity under drought through effective water capture, improved transpiration efficiency, and growth and yield and (v) breeding for water-limited environments through variety development, and trait-based genomics-assisted and transgenic approaches. This paper highlights some key issues and presents recommendations for future action. Improved agronomic interventions were recognised as being important contributors to improved dryland crop yields in water-limited environments, and new methods for exploring root architecture and water capture were highlighted. The increase in crop yields under drought through breeding and selection, the development of high-throughput phenotyping facilities for field-grown and pot-grown plants, and advances in understanding the molecular basis of plant responses and resistance to drought stress were recognised. Managed environment phenotyping facilities, a range of field environments, modelling, and genomic molecular tools are being used to select and release drought-resistant cultivars of all major crops. Delegates discussed how in iduals and small teams can contribute to progress, and concluded that interdisciplinary research, linkages to international agricultural research centres, public–private partnerships and continuation of the InterDrought conferences will be instrumental for progress.
Publisher: MDPI AG
Date: 27-02-2020
Abstract: Drought is one of the major abiotic stresses affecting the morphological, physiological, and metabolic processes of plants, and hence their growth and production on a global scale. Lucerne (Medicago sativa L.) is one of the most popular pasture species in semi-arid regions and plays a critical role in sustaining agricultural systems in many areas of the world. In order to evaluate the effect of water deficits on the growth and biomass distribution in different tissues of lucerne, plant height, leaf dry weight, leaf number and area, root dry weight, taproot length and lateral root number, and stem dry weight were measured at four stages from the seedling to flowering stages under three water regimes: (i) adequate water supply (minimum soil water content 85% pot capacity (PC)), (ii) moderate water stress (65% PC), and (iii) severe water stress (45% PC), imposed under a rainout shelter. With limited water supply, plant height, leaf number, leaf area and dry weight, taproot length, and total biomass were reduced, while lateral root numbers increased. The number of smaller leaves and root dry weight increased under moderate water stress, whereas severe water stress reduced them. Leaf, stem, and total dry weight were all reduced by the water deficits, but leaf dry weight was reduced the most and root dry weight the least, so there was a redistribution of biomass towards the roots, increasing the root–shoot ratio. These results help us to understand the response of lucerce to water stress and assist in developing a foundation for the sustainable use of lucerne in semi-arid agricultural systems.
Publisher: Elsevier
Date: 2011
Publisher: Wiley
Date: 03-2009
Publisher: Elsevier BV
Date: 06-1987
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/CP10161
Abstract: Grain yield depends on the number of grains per unit area (sink) and the availability of assimilates (source) to fill these grains. The aim of the current work was to determine whether wheat yield in the high-rainfall zone of south-western Australia is limited in current cultivars by the size of the sink or by the assimilates available for grain filling. Three wheat cultivars (Calingiri, Chara and Wyalkatchem) and two breeding lines (HRZ216 and HRZ203) were grown in four replicates in the field from 2005 to 2007. Dry matter and water soluble carbohydrates (WSC) at anthesis and maturity were measured and used to determine the source and sink balance of the crop. In 2007, three further treatments were applied to manipulate the sink–source relationships: (i) spikelets were removed on main stems to increase the source : sink ratio (ii) incoming solar radiation was reduced by 40% by shading after anthesis to reduce the availability of assimilates to grains and (iii) supplemental irrigation was used to maintain the capacity for photosynthesis by an improved water supply during grain filling. The source–sink balance of the crops showed that the potential source was 25% greater than the actual grain yield in average and above-average seasons (2005 and 2007), suggesting that sink size, represented by the number of grain per unit area, was a limiting factor to yield potential. However, the source may have become a limiting factor in a drought season (2006). The grain yield increased with increased number of grains/m2 and kernel weight remained relatively stable even when grain number increased from 7000 to 16 000 per m2. The removal of half of the spikelets on the main stem did not increase kernel mass of the remaining grains and an additional 33 mm of irrigation water did not increase grain yield, but significantly (P 0.05) increased WSC left in stems and leaf sheaths at maturity. Shading after anthesis did not significantly reduce grain yield of the current cultivars Calingiri and Wyalkatchem, but it reduced grain yield by 23–25% (P 0.05) in Chara and HRZ203. The source–sink balance over three seasons and three independent experiments in 2007 suggested that the yield of the current wheat cultivars is more sink- than source-limited and that breeding wheat with a larger sink size than in the current cultivars may lift the yield potential of wheat in the high-rainfall zone of south-western Australia.
Publisher: Elsevier
Date: 2005
Publisher: Frontiers Media SA
Date: 09-08-2017
Publisher: Wiley
Date: 03-01-2008
DOI: 10.1111/J.1399-3054.2007.01027.X
Abstract: Leaf carbon isotope discrimination (delta13C) was widely considered to directly reflect the rainfall environment in which the leaf developed, but recent observations have queried this. The relationship between delta13C and rainfall was explored in Eucalyptus species growing along a rainfall gradient in Australia. The leaves of 43 species of Eucalyptus and the closely related Corymbia species produced in 2003 were s led in September 2004 at 50 sites and grouped into 15 locations along a rainfall gradient in southwest Western Australia. At 24 sites, the same species and same trees were s led as in a study in September 2003 when leaves produced in 2002 were s led. The rainfall in 2004 was on average 190 mm (range 135-270 mm) higher at all locations than in 2003. In the leaves s led in 2004, the mean carbon isotope discrimination (delta13C) across the 15 locations decreased 2.9 per thousand per 1000 mm of rainfall, the specific leaf area (SLA) increased by 2.9 m2 kg(-1) per 1000 mm of rainfall and the nitrogen (N) content decreased by 1.56 g m(-2) per 1000 mm of rainfall. In contrast, a comparison between the leaves produced in the drier 2002 year compared with the wetter 2003 year showed that there was a strong correlation (r2= 0.85) between the SLA values between years and a trend for higher values with increasing SLA, but the values of delta(13)C were on average only 0.38 per thousand lower (more negative) at all locations in the wetter year, equivalent to a decrease of 2.0 per thousand per 1000 mm of rainfall. The results suggest that while there may be constitutive differences in leaf morphology, SLA and N content per unit area, increasing rainfall or cloudiness associated with higher rainfall increases SLA and decreases N content per unit area. We conclude that rainfall does not directly influence delta13C, but induces leaf morphological and physiological changes that affect the resultant delta13C.
Publisher: Frontiers Media SA
Date: 29-08-2017
Publisher: Wiley
Date: 07-09-2020
DOI: 10.1111/NPH.16845
Abstract: Clarifying the coordination of leaf hydraulic traits with gas exchange across closely‐related species adapted to varying rainfall can provide insights into plant habitat distribution and drought adaptation. The leaf hydraulic conductance ( K leaf ), stomatal conductance ( g s ), net assimilation ( A ), vein embolism and abscisic acid (ABA) concentration during dehydration were quantified, as well as pressure–volume curve traits and vein anatomy in 10 Caragana species adapted to a range of mean annual precipitation (MAP) conditions and growing in a common garden. We found a positive correlation between Ψ leaf at 50% loss of K leaf ( K leaf P 50 ) and maximum K leaf ( K leaf‐max ) across species. Species from low‐MAP environments exhibited more negative K leaf P 50 and turgor loss point, and higher K leaf‐max and leaf‐specific capacity at full turgor, along with higher vein density and midrib xylem per leaf area, and a higher ratio of K leaf‐max : maximum g s . Tighter stomatal control mediated by higher ABA accumulation during dehydration in these species resulted in an increase in hydraulic safety and intrinsic water use efficiency (WUE i ) during drought. Our results suggest that high hydraulic safety and efficiency combined with greater stomatal sensitivity triggered by ABA production and leading to greater WUE i provides drought tolerance in Caragana species adapted to low‐MAP environments.
Publisher: MDPI AG
Date: 08-05-2021
Abstract: Phosphorus (P) addition ameliorates the adverse effects of water stress on the seed yield of soybean (Glycine max L.). Previous studies focused on the effect of P on root traits, but little information is available on changes to aboveground traits. In this paper, we show how P addition affects shoot traits and reduces the adverse effects of water stress on the yield. Two soybean genotypes, with contrasting aboveground architectures, were grown in pots to compare the canopy architecture, leaf traits, aboveground dry matter accumulation and yield under two water and three P levels. The addition of P to two soybean genotypes, one with a larger number of branches and greater leaf area on the branches than the other, showed that the increased leaf area distribution on the main stem and branches was associated with increased shoot and root dry weights, which were positively correlated with the number of filled pods, seed number and seed yield and negatively correlated with seed size at maturity under well-watered and cyclic water stress treatments. The leaf P concentration at 65 DAS (flowering stage) and leaf photosynthesis measured shortly after re-watering increased with P addition, while the leaf mass area on the main stem at 65 DAS and maturity and on the branches at maturity increased modestly with P supply and water stress. Evidence is presented that P addition can ameliorate the adverse effects of water stress on yield through increased leaf area, leaf function and aboveground shoot production. We conclude that the increased yields of soybean resulting from increased P and water supplies that were previously shown to be associated with increased root growth and function are mediated through increased shoot growth and function, particularly the greater number of sites for pod production.
Publisher: Wiley
Date: 07-2014
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/AR05204
Abstract: The effect of water deficits at 2 growth stages on the physiology and growth of lentil (Lens culinaris Medikus subsp. culinaris) genotypes bred/selected for 3 regions was examined in a glasshouse experiment. The water regimes imposed were: (i) a well-watered control, (ii) water withheld at flowering, from 72 to 93 days after sowing (DAS), and (iii) water withheld from podding (93 DAS) to maturity. The genotypes were a West Asian genotype released in Australia (Cassab), 2 South Asian Nepali cultivars (Khajura 2 and Simal), and 3 crossbreds between West Asian and South Asian parents (ILL 6829, ILL 7979, and ILL 7982). ILL 7979 and Simal had significantly greater total dry matter, water use, seed yield, number of pods and seeds per plant, and harvest index (HI) than the other genotypes under well-watered conditions. Water deficits reduced seed yield by up to 60% in the crossbreds and the South Asian cultivar, Simal. However, seed yield was increased by the water deficit at flowering and the water deficit at podding in the West Asian genotype, Cassab, and the South Asian genotype, Khajura 2, respectively. In the other genotypes, withholding water at flowering or podding reduced leaf area (48–55%), total dry matter (32–50%), flower production (22–55%), and number of pods and seeds (27–66%), with significantly higher flower drop and empty pods when water was withheld. The higher seed yield in Cassab and Khajura 2 when water was withheld was related to the production of more flowers and the maintenance of pod and seed set when they were re-watered after the period of water deficit. When water was withheld during flowering, the West Asian genotype Cassab and the crossbred ILL 6829 used less water and hence maintained a high leaf water potential (ψleaf), whereas ψleaf decreased earlier to lower values in the crossbred ILL 7979 and the South Asian genotypes Khajura 2 and Simal. There were no significant differences in leaf net photosynthesis (PN), or stomatal conductance (gS), among genotypes during flowering and early podding, but PN and gS were reduced by 22–38 and 19–67%, respectively, when water was withheld. The lower ψleaf in ILL 7979, Simal, and Khajura 2 induced greater osmotic adjustment (OA) during the drying cycle at flowering, whereas there was no or little OA when water was withheld at podding. Variation in physiological traits (PN, gS, OA) under both watering regimes was not directly related to seed yield, but seed number was related to seed yield under both well-watered and water-deficit conditions.
Publisher: Springer Science and Business Media LLC
Date: 06-1983
DOI: 10.1007/BF00385228
Publisher: Wiley
Date: 05-1990
Publisher: Wiley
Date: 09-06-2023
DOI: 10.1111/PCE.14635
Abstract: While variation in mean annual precipitation (MAP) of the native habitat of a species has been shown to determine the ability of a species to resist a hydraulic decrease during drought, it remains unknown whether these variations in MAP also influence the ability of a species to recover and survive drought. Leaf hydraulic and gas exchange recovery following drought and the underlying mechanisms of these responses in six Caragana species from habitats along a large precipitation gradient were investigated during rehydration in a common garden. The gas exchange of species from arid habitats recovered more rapidly during rehydration after mild, moderate and severe drought stress treatments than species from humid habitats. The recovery of gas exchange was not associated with foliar abscisic acid concentration, but tightly related to the recovery of leaf hydraulic conductance ( K leaf ). The recovery of K leaf was associated with the loss of K leaf during dehydration under mild and moderate drought stress, and to leaf xylem embolism formation under severe drought stress. Results pointed to the different ability to recover in gas exchange in six Caragana species post‐drought is associated with the MAP of the species in its native habitat.
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/AR04118
Abstract: The effect of foliar application of isotopically labelled nitrogen (15N-urea) at 4 stages during flowering and podding on the uptake and utilisation of nitrogen by chickpea (Cicer arietinum L.) under conditions of terminal drought was investigated in a glasshouse study. Five treatments were used to investigate the effect of timing of foliar application of urea, equivalent to 30 kg N/ha, on the uptake and utilisation of nitrogen for biomass, yield, seed protein content, and seed size: foliar application at (i) first flower, (ii) 50% flowering, (iii) 50% pod set, and (iv) the end of podding, and (v) an unsprayed control treatment. Terminal drought was induced from pod set onward, resulting in a rapid development of plant water deficits (–0.14 MPa/day) and a decrease in leaf photosynthesis irrespective of the timing of foliar urea application. Foliar applications of urea at first flower and at 50% flowering, before terminal drought was induced, increased yield and seed protein content. The increase in yield resulted from an increase in the number of pods with more than one seed rather than from increased pod number per plant or increased seed size, indicating greater seed survival under terminal drought. Also, the increase in the seed protein content resulted from increased nitrogen availability for seed filling. Foliar application of urea during flowering, before terminal drought was induced, resulted in 20% more biomass at maturity, suggesting that growth prior to the development of water shortage increased the carbon resources for sustained seed filling under conditions of terminal drought. Foliar applications of urea at 50% pod set and at the end of podding did not affect the yield or seed protein content, primarily because the uptake of nitrogen was limited by the leaf senescence that occurred with the development of terminal drought. The results indicate the potential to increase yields of chickpea by application of foliar nitrogen near flowering in environments in which terminal droughts reduce yield.
Publisher: CSIRO Publishing
Date: 1992
DOI: 10.1071/AR9920541
Abstract: Increased early growth and total dry matter production have been suggested as useful traits to improve yield in Mediterranean-type environments. In Part I, genotypic variation for early growth and total dry matter production was identified among cultivars and some introduced lines. In this part, characteristics associated with early vigour in five of these introduced lines and ten Australian cultivars were examined in a field study at Wongan Hills in Western Australia. Differences in dry matter production were observed at all s ling times during the season, with three of the introduced lines (CEP 8058, Kansu No. 32 and V979-28) having consistently higher dry matter production than the standard cultivars during the early growth period. Those genotypes with a higher dry matter production at 54 days after sowing had higher relative growth rates and green area indices than those with low dry matter production. Both genotypes with large leaves on few tillers and genotypes with small leaves on many tillers had higher green area indices and higher dry matter production. While high dry matter production was associated with a large degree of ground cover and high light interception, it was not associated with the earlier commencement of reproductive development. Incorporation of early vigour and high dry matter production into locally adapted cultivars is required to demonstrate its benefit in these environments.
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/CP10125
Abstract: A pot and a field experiment were conducted to assess whether seeding density in winter wheat affects grain yield and water-use efficiency when combined with root pruning. Both experiments compared four treatments, namely (i) low (normal) plant density with no root pruning (ii) low plant density with root pruning (iii) high plant density (25% higher than low density) with no root pruning and (iv) high plant density with root pruning. Roots to a depth of 25 cm were cut back to keep their length to 13 cm and to limit their lateral spread to 13 cm from the plant. In the pot experiment, two water regimes were employed from stem elongation: (i) plants maintained at 85% field capacity, and (ii) plants maintained at 55% field capacity by regular watering. Low rainfall in spring at the terminal stage of plant growth served as natural water stress in the field experiment. In the field, the higher plant density induced higher root biomass at all s le depths at anthesis. Root pruning significantly decreased the root biomass in the upper soil layer (0–40 cm) and increased the root biomass in the deep soil layer (80–120 cm). When water was limited, increasing the seeding density by 25% reduced the grain yield, but with adequate water increasing the seeding density increased the grain yield. Root pruning increased the grain yield, but there was no interaction between seeding density and root pruning on grain yield in either the pots or field. Root pruning reduced water use between stem elongation and anthesis which led to more available soil water in the field between anthesis and maturity, and increased the rate of flag leaf photosynthesis at anthesis, whereas the reverse was true of increasing seeding density. Measurements of chlorophyll fluorescence suggested that initially root pruning induced a stress in the plants, but that the pruned plants rapidly recovered so that by anthesis and during grain filling the level of stress was reduced. Increasing the seeding density increased the number of spikes (fertile tillers), but decreased the grain yield per spike and had no effect on the thousand-kernel weight. In contrast, root pruning reduced the number of spikes in both the field and pots, but increased the grain yield per spike and thousand-kernel weight. Under our experimental conditions, restricting the root size by root pruning increased the yield and water-use efficiency of winter wheat in water-limited environments.
Publisher: MDPI AG
Date: 31-03-2021
Abstract: To understand the co-evolution in yield-related traits with the breeding, selection, and introduction of genotypes for increased grain yield, field experiments were carried out at two sites in the western area of the Loess Plateau in China that differed in hydrothermal conditions. Sixteen genotypes of spring wheat introduced and grown over the past 120 years were compared in terms of their yield and yield-related traits. As the grain yield increased, the spike number per unit area and the grain number per spike increased linearly, but the 1000-kernel weight was not correlated with grain yield. In the more recent genotypes, anthesis was initiated significantly earlier, although the length of the period from anthesis to maturity remained unchanged. Water use and the Effective Use of Water (EUW) for aboveground biomass before anthesis and the contribution of pre-anthesis aboveground biomass to grain yield all decreased as grain yield increased. Soil water content at anthesis was negatively correlated with aboveground biomass at anthesis, but positively correlated with grain yield. Conclusively, breeding in spring wheat over the past century has increased the yield of new genotypes by (1) increasing the number of grains per unit area (2) shortening the period of vegetative growth (3) decreasing EUW and the soil water use before anthesis thereby (4) retaining more soil water and increasing biomass accumulation after anthesis. Future spring wheat breeding for this dryland region should determine whether the time for grain filling from anthesis to maturity can be extended to enable greater use of environmental resources and higher yields.
Publisher: Wiley
Date: 06-09-2010
Publisher: Wiley
Date: 02-03-2010
DOI: 10.1111/J.1365-3040.2009.02051.X
Abstract: The growth of chickpea (Cicer arietinum L.) is very sensitive to salinity, with the most susceptible genotypes dying in just 25 mm NaCl and resistant genotypes unlikely to survive 100 mm NaCl in hydroponics germination is more tolerant with some genotypes tolerating 320 mm NaCl. When growing in a saline medium, Cl(-), which is secreted from glandular hairs on leaves, stems and pods, is present in higher concentrations in shoots than Na(+). Salinity reduces the amount of water extractable from soil by a chickpea crop and induces osmotic adjustment, which is greater in nodules than in leaves or roots. Chickpea rhizobia show a higher 'free-living' salt resistance than chickpea plants, and salinity can cause large reductions in nodulation, nodule size and N(2)-fixation capacity. Recent screenings of erse germplasm suggest significant variation of seed yield under saline conditions. Both dominance and additive gene effects have been identified in the effects of salinity on chickpea and there appears to be sufficient genetic variation to enable improvement in yield under saline conditions via breeding. Selections are required across the entire life cycle with a range of rhizobial strains under salt-affected, preferably field, conditions.
Publisher: Elsevier BV
Date: 08-2021
Publisher: Elsevier BV
Date: 10-2010
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/CP10372
Abstract: Predictions from climate simulation models suggest that by 2050 mean temperatures on the Loess Plateau of China will increase by 2.5 to 3.75°C, while those in the cropping region of south-west Australia will increase by 1.25 to 1.75°C. By 2050, rainfall is not expected to change on the Loess Plateau of China, while in south-west Australia rainfall is predicted to decrease by 20 to 60 mm. The frequency of heat waves and dry spells is predicted to increase in both regions. The implications of rising temperatures are an acceleration of crop phenology and a reduction in crop yields, greater risk of reproductive failure from extreme temperatures, and greater risk of crop failure. The reduction in yield from increased phenological development can be countered by selecting longer-season cultivars and taking advantage of warmer minimum temperatures and reduced frost risk to plant earlier than with current temperatures. Breeding for tolerance of extreme temperatures will be necessary to counter the increased frequency of extreme temperatures, while a greater emphasis on breeding for increased drought resistance and precipitation-use efficiency will lessen the impact of reduced rainfall. Management options likely to be adopted in south-west Australia include the introduction of drought-tolerant perennial fodder species and shifting cropping to higher-rainfall areas. On the Loess Plateau of China, food security is paramount so that an increased area of heat-tolerant and high-yielding maize, mulching with residues and plastic film, better weed and pest control and strategic use of supplemental irrigation to improve rainfall-use efficiency are likely to be adopted.
Publisher: Informa UK Limited
Date: 03-03-2016
Publisher: Springer Science and Business Media LLC
Date: 19-06-2020
DOI: 10.1186/S12870-020-02477-2
Abstract: The combination of mulch with N fertilizer application is a common agronomic technique used in the production of rainfed maize ( Zea mays L. ) to achieve higher yields under conditions of optimum planting density and adequate N supply. However, the combined effects of mulch, planting density, and N fertilizer application rate on plant N uptake and N translocation efficiency are not known. The objective of this study was to quantify the interaction effect of mulch, planting density, and N fertilizer application rate on maize grain yield, N uptake, N translocation, and N translocation efficiency. The experiment was arranged in a randomized complete block design with three factors (2 mulch levels × 2 planting densities × 4 N fertilizer application rates) replicated four times. There was a significant interaction among mulch, plant density, and N fertilizer on maize grain yield, kernel number per cob, N uptake, N translocation, and N translocation efficiency. Averaged over the 3 years of the study, total plant N uptake at silking ranged from 79 to 149 kg N ha − 1 with no mulch and from 76 to 178 kg N ha − 1 with mulch. The N uptake at silking in different plant organs ranked as leaf grain stem cob. Averaged across all factors, the highest N translocation was observed in leaves, which was 59.4 and 88.7% higher than observed in stems and ears, respectively. The mean vegetative organ N translocation efficiency averaged over mulch, planting density, and N fertilizer application rate treatments decreased in the order of leaf stem cob. Mulch, planting density, and N fertilizer application rate not only have significant effects on improving maize grain yield and NUE, but also on N uptake, N translocation, and N translocation efficiency. Our results showed clearly that under high planting density, the combination of mulch and moderate N fertilizer application rate was the optimal strategy for increasing maize grain yield and N use efficiency.
Publisher: Oxford University Press (OUP)
Date: 19-04-2017
DOI: 10.1093/JXB/ERW153
Publisher: Cambridge University Press (CUP)
Date: 02-02-2015
DOI: 10.1017/S0014479714000520
Abstract: The depth to ground water is increasing in several regions of the world due to use of high-yielding, but also high water-requiring crops such as rice ( Oryza sativa ) and wheat ( Triticum aestivum ), in order to maintain food security for an ever increasing world population. There is a need not only to increase the water productivity of food crops, but also to find less water-requiring crops. Irrigated chickpea ( Cicer arietinum L.), traditionally grown without irrigation, may provide an alternative crop to irrigated wheat in some regions. Two field experiments were conducted to determine the effects of irrigation on chickpea yields, yield components and grain and biomass water productivity (based on irrigation (WP I ) and irrigation + rainfall (WP I+R )) grown in a loamy sand soil. In the first year, 75 mm of irrigation at the vegetative stage and at the vegetative plus podding stages resulted in a 59% and a 73% increase in grain yield, respectively, compared to no irrigation, but with little change in WP I+R . Overall yields in the second year were significantly higher due to warmer temperatures and fewer frosts during flowering and podding. Compared to no irrigation, 75 mm of irrigation at flowering or at podding resulted in a 7% and a 27% increase in grain yield, but a decrease in grain and biomass water productivity (WP I+R ). Irrigation had a significant effect on the number of pods plant −1 in both the years and on 100-seed weight in the first year. We conclude that application of a single irrigation during podding to chickpea grown in a loamy sand soil will reliably increase yields and may provide a water-saving alternative to wheat in water-scarce environments.
Publisher: MDPI AG
Date: 07-03-2019
Abstract: Drought is one of the most harmful environmental stresses affecting the physiological, biochemical processes and growth of plants. Lucerne or alfalfa (Medicago sativa L.), one of the most popular pasture species in arid and semi-arid regions, plays a critical role in sustaining agricultural systems in many areas of the world. In order to evaluate the effect of water shortage on water status, biomass distribution and proline content, the relative water content (RWC), biomass and proline concentration in the leaves, stems and roots of lucerne seedlings under three different water regimes were studied in pots under a rainout shelter. The results showed that after water was withheld, the RWC of the different organs decreased significantly at the same soil water content, the leaf RWC was higher than that of the stem and root. The biomass of the leaves, stems and roots were all reduced by water stress, while the root–shoot ratio increased indicating that the roots were less affected than the leaves and stems. Proline concentration increased with decreasing soil water content with the leaf proline concentration increasing more than that of stems and roots. These results indicate that roots of lucerne seedlings show greater resilience to water deficits than shoots.
Publisher: Wiley
Date: 06-2007
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/CP09288
Abstract: Knowledge of the contribution of ear number per unit area, grains per ear, and kernel weight to grain yield is important in understanding the limits to the water-limited potential yield of wheat in rain-fed agricultural regions. This paper analyses the relationships between grain yield, yield components and growing-season rainfall using data from the low-, medium-, and high-rainfall zones of the cropping region of south-western Australia. The aim of the paper is to quantify the contribution of ear number, grains per ear and kernel weight to grain yield and define the yield components of wheat required to achieve its water-limited yield. The grain yield of wheat was closely related to the number of grains per unit area (r2 = 0.90) and ears/m2 (r2 = 0.75), but poorly correlated with kernel weight (r2 = 0.30) and grains/ear (r2 = 0.09). The number of grains per unit area was highly related (r2 = 0.75) to the number of ears per unit area across the rainfall zones of the cropping region, and strongly correlated (r2 = 0.88–0.94) to the spike dry weight at anthesis. The highest yields achieved in the field were close to the water-limited potential estimated using the French and Schultz method. To achieve this water-limited potential, wheat requires 1 ear per m2 for every mm of growing-season rainfall (r2 = 0.92). We conclude that the number of ears per unit area is the most important factor required in order to achieve high yields of up to a yield of 6 t/ha in wheat in rain-fed south-western Australia.
Publisher: Springer Science and Business Media LLC
Date: 10-1988
DOI: 10.1007/BF00296704
Publisher: Wiley
Date: 04-1991
Publisher: Elsevier BV
Date: 02-2006
Publisher: Engineering Sciences Press
Date: 2017
Publisher: Elsevier BV
Date: 11-2016
Publisher: Authorea, Inc.
Date: 11-09-2023
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 03-2020
Publisher: Springer Science and Business Media LLC
Date: 22-05-2015
Publisher: Springer Science and Business Media LLC
Date: 12-09-2017
DOI: 10.1038/S41598-017-11294-X
Abstract: Seed germination behavior is an important factor in the distribution of species. Many studies have shown that germination is controlled by phylogenetic constraints, however, it is not clear whether phylogenetic constraints or environmental cues explain seed germination of a genus from a common ancestor. In this study, seed germination under different temperature- and water-regimes [induced by different osmotic potentials of polyethylene glycol (PEG)] was investigated in the phylogenetically-related Caragana species that thrive in arid, semiarid, semihumid and humid environments. The results showed that the final percentage germination (FPG) decreased from 95% in species from arid habitats to 0% in species from humid habitats, but with no significant phylogenetic signal. Rather, the response of seed germination to temperature and PEG varied greatly with species from arid to humid habitats and was tightly linked to the ecological niche of the species, their seed coat structure and abscisic acid concentration. The findings are not consistent with the hypothesis that within a family or a genus, seed germination strategies can be a stable evolutionary trait, thus constraining interspecific variation, but the results clearly show that seed germination of Caragana species distributed across a range of habitats has adapted to the environment of that habitat.
Publisher: Wiley
Date: 03-1994
Publisher: Wiley
Date: 11-03-2016
DOI: 10.1111/JAC.12128
Publisher: CSIRO Publishing
Date: 2000
DOI: 10.1071/AR00018
Abstract: In the Mediterranean-type environment of south-western Australia, pod filling of chickpea occurs when net photosynthesis and nitrogen fixation is low as a result of the onset of terminal drought. Remobilisation of carbon (C) and nitrogen (N) from vegetative parts to developing seed may be an important alternative source of C and N for seed filling. The contribution of stored pre-podding C and N to seed filling was studied by labelling the vegetative tissues with the stable isotopes, 13C and 15N, prior to podding and following their subsequent movement to the seed. In ICCV88201, an advanced desi breeding line, 9% of the C and 67% of the N in the seed were derived from pre-podding C and N in well-watered plants compared with 13% of the seed C and 88% of the seed N in water-stressed plants. Furthermore, the contribution of pre-podding C and N was higher for earlier set compared with later set seeds. Pre-podding C and N were derived predominantly from the leaves with relatively little from the stems, roots, and pod walls. Genotypic variation in remobilisation ability was identified in contrasting desi (Tyson) and kabuli (Kaniva) cultivars. In well-watered Tyson, 9% of the seed C and 85% of the seed N were remobilised from vegetative tissues compared with 7% of the seed C and 62% of seed N in well-watered Kaniva. Water deficit decreased the amount of C remobilised by 3% in Tyson compared with 66% in Kaniva, whereas the total amount of N remobilised was decreased by 11% in Tyson and 48% in Kaniva. This was related to the maintenance of greater sink strength in Tyson, in which the number of filled pods was reduced by 66% in stressed plants compared with a 91% decrease in Kaniva. This indicates that better drought tolerance in desi genotypes is partly a consequence of better remobilisation and higher pod number. These studies show that C and N assimilated prior to podding can supplement the supply of current assimilates to the filling seed in both well-watered and water-stressed chickpea. Remobilisation of pre-podding N is an essential source of N for seed filling irrespective of environmental stress.
Publisher: Springer Science and Business Media LLC
Date: 09-08-2013
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/AR04297
Abstract: Water use of wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), canola (Brassica napus L.), and lucerne (Medicago sativa L.) was measured on a duplex soil in the high rainfall zone (HRZ) of south-western Australia from 2001 to 2003. Rainfall exceeded evapotranspiration in all years, resulting in transient perched watertables, subsurface waterlogging in 2002 and 2003, and loss of water by deep drainage and lateral flow in all years. There was no significant difference in water use among wheat, barley, and canola. Lucerne used water at a similar rate to annual crops during the winter and spring, but continued to extract 80−100 mm more water than the annual crops over the summer and autumn fallow period. This resulted in about 50 mm less drainage past the root-zone than for annual crops in the second and third years after the establishment of the lucerne. Crop water use was fully met by rainfall from sowing to anthesis and a significant amount of water (120−220 mm) was used during the post-anthesis period, resulting in a ratio of pre- to post-anthesis water use (ETa : ETpa) of 1 : 1 to 2 : 1. These ratios were lower than the indicative value of 2 : 1 for limited water supply for grain filling. High water use during the post-anthesis period was attributed to high available soil water at anthesis, a large rooting depth (≥1.4 m), a high proportion (15%) of roots in the clay subsoil, and regular rainfall during grain filling. The pattern of seasonal water use by crops suggested that high dry matter at anthesis did not prematurely exhaust soil water for grain filling and that it is unlikely to affect dry matter accumulation during grain filling and final grain yield under these conditions.
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/CP10349
Abstract: Terminal drought is known to decrease flower production, increase flower and pod abortion, and decrease yield of chickpea (Cicer arietinum L.), but the effects of early-season drought have not been evaluated. The influence of an early transient water deficit on flower and pod production and abortion, and seed yield and its components was evaluated in two chickpea cultivars, Rupali, a desi type, and Almaz, a kabuli type. Thirty-six-day-old plants were subjected to: (i) a transient water deficit by withholding water for 35 days, and then rewatered (WS), and (ii) kept well watered (WW) throughout. In the WS treatment the soil water content, leaf relative water content and leaf photosynthetic rate decreased after water was withheld and, following rewatering, recovered to the WW level. Despite the WS treatment being imposed at different phenological stages in the two cultivars, WS reduced flower number per plant by ~50% in Rupali and Almaz, respectively, compared with the WW plants. In WW plants, ~15% of flowers aborted in both cultivars, and 42 and 67% of the pods aborted in Rupali and Almaz, respectively, whereas in WS plants, 18 and 23% of flowers aborted and 27 and 67% of pods aborted in Rupali and Almaz, respectively. While seed growth in WS plants of Rupali and Almaz occurred primarily after the plants were rewatered, the duration of seed growth decreased by 17 and 36 days, the maximum rate of seed filling increased by 3 times and 5 times, and seed size increased by 26 and 16%, respectively, compared with the WW plants. Seed yield per plant in WS plants decreased by 31% in Rupali and 38% in Almaz compared with the WW controls. The early transient water deficit decreased flower production, but improved flower and pod development increased the rate of seed growth and increased final seed size and had a smaller effect on seed yield compared with chickpea subjected to terminal drought.
Publisher: Elsevier
Date: 2013
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/EA05150
Abstract: Annual cropping has been expanding in the high rainfall zone of southern Australia. The higher rainfall and longer growing season compared with the traditional wheatbelt contribute to a much higher yield potential for major crops. Potential yields range from 5 to 8 t/ha for wheat and 3 to 5 t/ha for canola, although current crop yields are only about 50% of those potentials. The large yield gap between current and potential yields suggests that there is an opportunity to lift current yields. Both genetic constraints and subsoil constraints such as waterlogging, soil acidity, sodicity, and high soil strength contribute to the low yields. Waterlogging is a widespread hidden constraint to crop production in the region. Controlling waterlogging using a combination of raised beds and surface or subsurface drains is the first step to raise the productivity of the land. Increasing root growth into the subsoil remains a key to accessing more water and nutrients for high yield through early planting, deep ripping, liming and use of primer crops to ameliorate the subsoil. In order to realise the high yield potential, it is essential to achieve higher optimum dry matter at anthesis and high ear number through agronomic management, including early sowing with appropriate cultivars, a high seeding rate and application of adequate nitrogen along with other nutrients. Current cultivars of spring wheat may not fully utilise the available growing season and may have genetic limitations in sink capacity that constrain potential yield. Breeding or identification of long-season milling wheat cultivars that can fully utilise the longer growing season and with the ability to tolerate waterlogging and subsoil acidity, and with disease resistance, will give additional benefits. It is concluded that improving crop production in the high rainfall zone of southern Australia will require attention to overcoming soil constraints, particularly waterlogging, and the development of longer-season cultivars.
Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier
Date: 2000
Publisher: Elsevier BV
Date: 02-2014
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/FP11148
Abstract: In south-west Australia, winter grown crops such as wheat and lupin often experience transient waterlogging during periods of high rainfall. Wheat is believed to be more tolerant to waterlogging than lupins, but until now no direct comparisons have been made. The effects of waterlogging on root growth and anatomy were compared in wheat (Triticum aestivum L.), narrow-leafed lupin (Lupinus angustifolius L.) and yellow lupin (Lupinus luteus L.) using 1 m deep root observation chambers. Seven days of waterlogging stopped root growth in all species, except some nodal root development in wheat. Roots of both lupin species died back progressively from the tips while waterlogged. After draining the chambers, wheat root growth resumed in the apical region at a faster rate than well-drained plants, so that total root length was similar in waterlogged and well-drained plants at the end of the experiment. Root growth in yellow lupin resumed in the basal region, but was insufficient to compensate for root death during waterlogging. Narrow-leafed lupin roots did not recover they continued to deteriorate. The survival and recovery of roots in response to waterlogging was related to anatomical features that influence internal oxygen deficiency and root hydraulic properties.
Publisher: CSIRO Publishing
Date: 1999
DOI: 10.1071/EA98134
Abstract: The influence of terminal drought on the seed growth of 3 chickpea (Cicer arietinum L.) genotypes was examined in a field experiment at Merredin, Western Australia. Tyson, a small-seeded desi cultivar, ICCV88201, a desi breeding line (sister line to the recently released Sona cultivar) with medium-sized seed, and Kaniva, a kabuli cultivar with large seed, were grown under rainfed and irrigated conditions. In the rainfed plots, leaf water potential had decreased from above –1.2 MPa to about –2.5 MPa and net photosynthesis from 21 to 29 µmol CO2/m2. s to below 10 µmol CO2/m2.s, by the time seed filling commenced. Rainfed plants had significantly fewer pods than irrigated plants, regardless of genotype. In rainfed plants average seed weight was reduced by 19, 23 and 34% and yield by 74, 52 and 72% in Tyson, ICCV88201, and Kaniva respectively. In idual pods were tagged at pod set on previously-selected representative plants and were weighed separately from the rest of the plant over 6 subsequent harvests so that the rate and duration of seed fill could be measured. Genotypic differences in the maximum rate of seed fill were found to exist in chickpea. In both irrigated and rainfed conditions, Kaniva had the highest maximum rate of seed fill followed by ICCV88201 and Tyson. Both the rate and duration of seed growth were reduced in the rainfed plants, regardless of genotype. Reductions in the dry weight of the pod shell suggest that the remobilisation of dry matter from the pod may contribute 9–15% of the seed weight in rainfed chickpea.
Publisher: Wiley
Date: 04-03-2015
DOI: 10.1111/PCE.12506
Abstract: The reproductive phase in chickpea (Cicer arietinum L.) is affected by salinity, but little is known about the underlying cause. We investigated whether high concentrations of Na(+) and Cl(-) in the reproductive structures influence reproductive processes. Chickpea genotypes contrasting in tolerance were subjected to 0, 35 or 50 mm NaCl applied to soil in pots. Flower production and abortion, pod number, percentage of empty pods, seed number and size were evaluated. The concentrations of Na(+) , K(+) and Cl(-) were measured in various plant tissues and, using X-ray microanalysis, in specific cells of developing reproductive structures. Genotypic variation in reproductive success measured as seed yield in saline conditions was associated with better maintenance of flower production and higher numbers of filled pods (and thus seed number), whereas seed size decreased in all genotypes. Despite the variation in reproductive success, the accumulation of Na(+) and Cl(-) in the early reproductive tissues of developing pods did not differ between a tolerant (Genesis836) and a sensitive (Rupali) genotype. Similarly, salinity tolerance was not associated with the accumulation of salt ions in leaves at the time of reproduction or in seeds at maturity.
Publisher: Springer Science and Business Media LLC
Date: 08-06-1998
Abstract: Attempts to improve water use efficiency in regions with Mediterranean climates generally focus on increasing plant transpiration relative to evaporation from the soil and increasing transpiration efficiency. Our aim was to determine if transpiration efficiency differs among key species occurring in annual pastures in southern Australia. Two glasshouse experiments were conducted with three key pasture species, subterranean clover (Trifolium subterraneum L.), capeweed [Arctotheca calendula (L.) Levyns] and annual ryegrass (Lolium rigidum Gaudin), and wheat (Triticum aestivum L.). Transpiration efficiency was assessed at the levels of␣whole-plant biomass and water use (W), leaf gas exchange measurements of the ratio of CO
Publisher: Elsevier BV
Date: 12-1998
Publisher: Elsevier BV
Date: 02-2002
Publisher: Oxford University Press (OUP)
Date: 22-10-2022
DOI: 10.1093/JXB/ERAC424
Abstract: Accurate measurement of plant transpiration is critical to gaining a better understanding of plant water use and exploration of the influence of plants on regional and even global climate. Heat tracer-based sap flow (HTSF) techniques are currently the dominant method to estimate plant transpiration at the in idual plant level. However, the majority of current research focuses on specific applications or the evaluation of the method itself, and there is a lack of an overall analysis of HTSF methods. The objectives of this study were: (i) to briefly review the theories and categories of the various HTSF methods, and (ii) to undertake a bibliometric analysis of the use of HTSF methods in measuring plant transpiration. Each HTSF method is described mathematically and their application and pros and cons are briefly discussed. A bibliometric analysis was conducted using 3964 papers published between 1992 and 2020 archived in the Web of Science core collection. The analysis identified publication trends, the most productive authors, organizations, and countries, as well as the most utilized HTSF method (i.e., thermal dissipation) and journals in which these papers were published. In addition, world distribution maps of the use of HTSF methods and tree species measured were drawn based on 741 selected publications with in situ measurements.
Publisher: Elsevier BV
Date: 08-2006
Publisher: CSIRO Publishing
Date: 2003
DOI: 10.1071/FP03084
Abstract: Chickpea (Cicer arietinum L.) is characterised by a different adaptation profile from the other crops of West Asian origin such as pea, barley, and wheat. In this paper we suggest that a series of four evolutionary bottlenecks occur in chickpea: (1) the scarcity and limited distribution of the wild progenitor, C. reticulatum Ladiz., (2) the founder effect associated with domestication, (3) the shift, early in the crop's history, from winter to spring sowing, and the attendant change from using rainfall as it occurs to a reliance on residual soil moisture, and (4) the replacement of locally evolving landraces by elite cultivars produced by modern plant breeding. While two of the bottlenecks are common to all species, the limited distribution of the wild progenitor and shift of cropping from utilisation of current rainfall to stored soil moisture is unique to chickpea. In this paper we suggest that in order to widen the genetic base of cultivated chickpea it is imperative to reintroduce traits from across the primary gene pool. Moreover, a comparative physiological approach to the study of adaptation among the annual wild relatives of chickpea may reveal adaptive strategies within the genus currently obscured by monomorphic loci. The poor state of the world collection of annual wild Cicer species severely constrains the implementation of both these imperatives. We suggest that an extensive collection of annual wild Cicer species, based on ecogeographic principles to maximise the probability of collecting erse ecotypes, should provide a better understanding of the biology and adaptation in this ancient crop and lead to improved productivity.
Publisher: Wiley
Date: 29-06-2001
Publisher: CSIRO Publishing
Date: 2000
DOI: 10.1071/AR99108
Abstract: The impact of water stress and infestations of redlegged earth mite [Halotydeus destructor Tucker (Acarina : Penthaleidae)] on the early growth and botanical composition of a mixed subterranean clover (Trifolium subterraneum L.) and capeweed (Arctotheca calendula Levyns) pasture was investigated in a controlled environment experiment. Water stress and redlegged earth mite infestations both significantly reduced herbage production from both species. The yield of the subterranean clover was suppressed less by water stress than that of the capeweed. The differing sensitivities of the two species to water stress were attributed to differences in seedling size and growth rates at the onset of the drought. Redlegged earth mites caused greater feeding damage on cotyledons of the subterranean clover than of the capeweed. Despite this, the mites had a greater deleterious impact on the growth of the capeweed, which was suppressed both in the presence and absence of water stress. Redlegged earth mites in the presence of water stress did not significantly affect the growth of the subterranean clover. Furthermore, in the absence of water stress, the growth of the subterranean clover was greater when mites were present than when absent. The greater sensitivity of the capeweed to the effects of feeding by the redlegged earth mites was attributed to the smaller size of its seedlings at the time the redlegged earth mites were introduced. The increase in growth of the subterranean clover following the introduction of redlegged earth mites is more likely due to a change in the competitive relationships between the two plant species than to any direct effect of the mites’ feeding. Our observations indicate that the presence of water stress and redlegged earth mites significantly affects the competitive interactions between seedlings of subterranean clover and capeweed.
Publisher: CSIRO Publishing
Date: 1999
DOI: 10.1071/EA98132
Abstract: A glasshouse experiment examined the effect of water stress on the growth of Lupinus angustifolius L. and Lupinus pilosus Murr. grown on an acid sandy soil, a limed sandy soil and an alkaline clay soil. Decreasing soil water content decreased the stomatal conductance and photosynthetic rate, and reduced plant growth. The responses of both species to water stress were generally similar in the sand and limed soils, but in the alkaline soil, L. angustifolius grown with limited water had markedly lower conductances and photosynthetic rates than the plants in the other soils at equivalent soil water contents. In adequately watered plants, the lupin species differed substantially in their growth response to soil types. Whereas the growth of L. pilosus was unaffected, the shoot dry weight of L. angustifolius grown on the limed and alkaline soils for 25–44 days was reduced by 32–54 and 44–86%, respectively, compared with the growth in the acid soil. The poor growth of L. angustifolius appeared to be primarily due to its poor root growth. In the alkaline soil, water stress reduced rather than stimulated root growth. The results suggest that, in the field, the limited root growth of L. angustifolius on alkaline soils will exacerbate water deficits when the topsoil dries out in the latter part of the season.
Publisher: Springer Science and Business Media LLC
Date: 02-10-2011
Publisher: MDPI AG
Date: 14-01-2020
Abstract: Water is the main factor limiting soybean yield and the timely supply of supplemental irrigation could increase the grain yield, but the effects of a supplemental water supply on soybean yields have not been well studied. Field and pot experiments were conducted to compare the grain yield, yield components, water use efficiency for grain yield (WUEG), flower number, filled-pod number, soil water content, and root dry weight at different depths with and without supplemental irrigation at flowering. Field experiments showed that compared to rainfed conditions, 40 mm of water applied during flowering significantly increased grain yield by 26%, WUEG by 12%, filled-pod number by 16%, grain number by 13.3%, and water uptake from soil by 11% in 2011, and increased grain yield by 22%, WUEG by 7%, filled-pod number by 26%, grain number by 27%, and water uptake by 21% in 2012. The soil water content in the subsoil (1.2–2.0 m) layers under the irrigated treatment was lower, indicating greater water extraction, than in the rainfed treatment and water uptake was significantly and positively correlated with yield in both years. In a pot experiment, flower and filled-pod number, water use during flowering and podding were significantly higher in the well-watered (WW) treatment than cyclic water stress (WS) treatment. Flower number and filled-pod number were significantly and positively correlated with water use during flowering and podding, respectively, under both the WW and WS treatments. The root dry weight was higher in the 0.2–0.8 m soil layer in the WW treatment than the WS treatment. We conclude that supplementary water at flowering increased the water uptake from deeper soil layers by increasing the distribution of roots in the subsoil layers that resulted in the production of more flowers and filled pods and increased the WUEG and grain yield.
Publisher: Wiley
Date: 30-05-2006
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/FP09172
Abstract: Little is known about water flow across intact root cells and roots in response to hypoxia. Responses may be rapid if regulated by aquaporin activity, but only if water crosses membranes. We measured the transport properties of roots and cortical cells of three important crop species in response to hypoxia (0.05 mol O2 m–3): wheat (Triticum aestivum L.), narrow-leafed lupin (Lupinus angustifolius L.) and yellow lupin (Lupinus luteus L.). Hypoxia influenced solute transport within minutes of exposure as indicated by increases in root pressure (Pr) and decreases in turgor pressure (Pc), but these effects were only significant in lupins. Re-aeration returned Pr to original levels in yellow lupin, but in narrow-leafed lupin, Pr declined to zero or lower values without recovery even when re-aerated. Hypoxia inhibited hydraulic conductivity of root cortical cells (Lpc) in all three species, but only inhibited hydraulic conductivity of roots (Lpr) in wheat, indicating different pathways for radial water flow across lupin and wheat roots. The inhibition of Lpr of wheat depended on the length of the root, and inhibition of Lpc in the endodermis could account for the changes in Lpr. During re-aeration, aquaporin activity increased in wheat roots causing an overshoot in Lpr. The results of this study demonstrate that the roots of these species not only vary in hydraulic properties but also vary in their sensitivity to the same external O2 concentration.
Publisher: Springer Science and Business Media LLC
Date: 13-07-2015
DOI: 10.1038/SREP12130
Abstract: Understanding the relationships between vegetative and environmental variables is important for revegetation and ecosystem management on the Loess Plateau, China. Lucerne ( Medicago sativa L.) has been widely used in the region to improve revegetation, soil and water conservation and to enhance livestock production. However, there is little information on how environmental factors influence long-term succession in lucerne-rich vegetation. Our objective was to identify the main environmental variables controlling the succession process in lucerne-rich vegetation such that native species are not suppressed after sowing on the Loess Plateau. Vegetation and soil surveys were performed in 31 lucerne fields (three lucerne fields without any management from 2003–2013 and 28 fields containing 11-year-old lucerne with one cutting each year). Time after planting was the most important factor affecting plant species succession. Cutting significantly affected revegetation characteristics, such as aboveground biomass, plant density and ersity. Soil moisture content, soil organic carbon, soil available phosphorus and slope aspect were key environmental factors affecting plant species composition and aboveground biomass, density and ersity. Long-term cutting can cause self-thinning in lucerne, maintain the stability of lucerne production and slow its degradation. For effective management of lucerne fields, phosphate fertilizer should be applied and cutting performed.
Publisher: Elsevier BV
Date: 02-2002
Publisher: American Chemical Society (ACS)
Date: 24-02-2011
DOI: 10.1021/IE102259S
Publisher: CSIRO Publishing
Date: 1999
DOI: 10.1071/AR98109
Abstract: There is a perception in the farming and research communities that annual pastures have low produc- tivity and water use, and contribute disproportionately to problems of rising watertables and dryland salinity. Our aim was to determine potential pasture production in relation to water use and the influence of management factors on this relationship. Experiments were initiated at 4 locations along a gradient of 300–1100 mm annual rainfall across the Western Australian agricultural zone. At each site a high input treatment was compared with a low input control. There was a strong linear relationship between water use and pasture production up to 440 mm of growing- season water use. After 30 mm of water use the potential pasture production was 30 kg/ha.mm. An upper limit to pasture production may be reached at about 12 000 kg/ha in this environment due to rainfall distribution patterns and soil water holding capacity in the root-zone. Although pasture production was increased by as much as 3500 kg/ha, water use was generally similar or only slightly more for high input compared with control plots. The marginally higher water use by the high input pastures resulted in an extra 18 mm of water extracted from the subsoil at one location by the end of the third season. A drier subsoil may provide a buffer for storing excess rainfall and reduce deep drainage. Estimated drainage was small at low rainfall sites so even marginal increases in water use by highly productive annual pastures could play a significant role in reducing water loss to deep drainage and mitigating water-table rise and secondary salinisation in low rainfall regions. Management practices aimed at promoting early growth and adequate leaf area should maximise water use, water use efficiency, and yield. The linear relationship defining potential pasture production provides a useful benchmark to farmers.
Publisher: Elsevier BV
Date: 11-2016
Publisher: Wiley
Date: 21-07-2015
DOI: 10.1111/JAC.12143
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/FP12335
Abstract: Leaf canopy temperature has been proposed as a rapid selection tool for drought tolerance among crop genotypes. However, floral bud temperature may be a better indicator of drought tolerance than leaf temperature in grain crops. In this study, we examined whether the floral bud and leaves of Brassica rapa L. had similar stomatal characteristics and showed similar water loss during a drying cycle. We also compared the leaf and bud temperatures when the plants were exposed to a 10-day transient water stress during reproductive development that affected flower development, increased flower abortion, increased pod abortion and reduced yield by an average of 85%. The water loss of detached leaves and floral buds showed that the stomata on the leaves closed before those of the floral buds as the leaf water potential decreased. Consistent with the water loss studies, the temperature of the intact bud showed a delayed increase during the drying process compared with the leaves. This suggested that floral bud temperature could be a useful indicator of the water status of the reproductive organs of B. rapa.
Publisher: Elsevier BV
Date: 12-2019
Publisher: Springer Science and Business Media LLC
Date: 2001
Abstract: In previous work, we provided evidence from sap flow measurements that when root systems span soil layers of different moisture content, water is redistributed by roots in the direction of the difference in water potential. In addition to the phenomenon termed "hydraulic lift", where water is redistributed from depth to dry topsoil, the process of "hydraulic redistribution" includes downward transfer of water when the surface layers of soils with low permeability become wet after rainfall. In this paper, we support our previous findings with evidence from measurements of soil water and estimate the quantities of water transferred to depth following rain. Amounts of water stored at depth are not likely to be significant for drought avoidance by plants. However, downward transfer of water may be important to plant establishment and the reduction of waterlogging in certain soil types.
Publisher: Wiley
Date: 29-08-2001
DOI: 10.1002/JSFA.939
Publisher: Oxford University Press (OUP)
Date: 31-10-2002
DOI: 10.1093/AOB/MCF253
Abstract: Like those of many horticultural crop species, the growth and leaf gas exchange responses of carrot (Daucus carota L.) to salinity are poorly understood. In this study ion accumulation in root tissues (periderm, xylem and phloem tissues) and in leaves of different ages was assessed for carrot plants grown in the field with a low level of salinity (5.8 mM Na(+) and 7.5 mM Cl(-)) and in a glasshouse with salinity ranging from 1-80 mM. At low levels of salinity (1-7.5 mM), in both the field and glasshouse, carrot leaves accumulated high concentrations of Cl(-) (140-200 mM) these appear to be the result of a high affinity for Cl(-) uptake and a low retention of Cl(-) in the root system. However, Cl(-) uptake is under tight control, with an 80-fold increase in external salinity resulting in only a 1.5-fold change in the Cl(-) concentration of the shoot and no increase in the Cl(-) concentration of the root xylem tissue. In contrast to Cl(-), shoot Na(+) concentrations were comparatively low (30-40 mM) but increased by seven-fold when salinity was increased by 80-fold. Growth over the 56-d treatment period in the glasshouse was insensitive to salinity less than 20 mM, but at higher concentrations the yield of carrot tap roots declined by 7 % for each 10 mM increase in salinity. At low levels of salinity the accumulation of high concentrations of Cl(-) (150 mM) in carrot laminae did not appear to limit leaf gas exchange. However, photosynthesis and stomatal conductance were reduced by 38 and 53 %, respectively, for plants grown at a salinity of 80 mM compared with those grown at 1 mM. Salinity-induced reductions in both p(i) and carbon isotope discrimination (delta) were small (2.5 Pa and 1.4 per thousand, respectively, at 80 mM) indicating that the reduction in photosynthesis was only marginally influenced by CO(2) supply. At a salinity of 80 mM the photosynthetic capacity was reduced, with a 30 % reduction in the CO(2)-saturated rate of photosynthesis (A(max)) and a 40 % reduction in both the apparent rate of RuBP-carboxylase-limited CO(2) fixation (V(cmax)) and the electron transport rate limiting RuBP regeneration (J(max)). This study has shown that carrot growth and leaf gas exchange are insensitive to the high leaf Cl(-) concentrations that occur at low levels (1-7 mM) of salinity. However, growth is limited at salinity levels above 20 mM and leaf gas exchange is limited at salinity levels above 8 mM.
Publisher: Springer Science and Business Media LLC
Date: 2002
Publisher: Wiley
Date: 04-06-2007
DOI: 10.1111/J.1365-3040.2007.01678.X
Abstract: Hydrostatic pressure relaxations with the root pressure probe are commonly used for measuring the hydraulic conductivity (Lp(r)) of roots. We compared the Lp(r) of roots from species with different root hydraulic properties (Lupinus angustifolius L. 'Merrit', Lupinus luteus L. 'Wodjil', Triticum aestivum L. 'Kulin' and Zea mays L. 'Pacific DK 477') using pressure relaxations, a pressure cl and osmotic gradients to induce water flow across the root. Only the pressure cl measures water flow under steady-state conditions. Lp(r) determined by pressure relaxations was two- to threefold greater than Lp(r) from pressure cl s and was independent of the direction of water flow. Lp(r) (pressure cl ) was two- to fourfold higher than for Lp(r) (osmotic) for all species except Triticum aestivum where Lp(r) (pressure cl ) and Lp(r) (osmotic) were not significantly different. A novel technique was developed to measure the propagation of pressure through roots to investigate the cause of the differences in Lp(r). Root segments were connected between two pressure probes so that when root pressure (P(r)) was manipulated by one probe, the other probe recorded changes in P(r). Pressure relaxations did not induce the expected kinetics in pressure in the probe at the other end of the root when axial hydraulic conductance, and probe and root capacitances were accounted for. An electric circuit model of the root was constructed that included an additional capacitance in the root loaded by a series of resistances. This accounted for the double exponential kinetics for intact roots in pressure relaxation experiments as well as the reduced response observed with the double probe experiments. Although there were potential errors with all the techniques, we considered that the measurement of Lp(r) using the pressure cl was the most unambiguous for small pressure changes, and provided that sufficient time was allowed for pressure propagation through the root. The differences in Lp(r) from different methods of measurement have implications for the models describing water transport through roots and the potential role of aquaporins.
Publisher: Wiley
Date: 12-02-2020
DOI: 10.1111/JAC.12393
Publisher: Springer Science and Business Media LLC
Date: 29-11-2018
Publisher: Wiley
Date: 19-07-2013
DOI: 10.1111/JAC.12034
Publisher: Oxford University Press (OUP)
Date: 12-05-2010
Abstract: One-year-old sun leaves of 60 species of Eucalyptus were collected in August 2005 at an arboretum in South Australia with a mean annual rainfall of 427 mm, and 14 of the same species were s led at an arboretum in Western Australia with a mean annual rainfall of 216 mm. We determined the genetic and phenotypic variation in carbon isotope composition (delta13C), specific leaf area (SLA) and nitrogen content per unit area of the species at each site. There were very significant (P < 0.001) differences in delta13C among the species at both sites. The mean delta13C of the 60 species at the wetter site was -27.6 per thousand (from -25.8 per thousand in Eucalyptus youngiana to -29.9 per thousand in Eucalyptus salicola) and of the 14 species at the drier site was -25.3 per thousand (from -23.7 per thousand in Eucalyptus ravida to -27.3 per thousand in Eucalyptus ewartiana). Of the 14 species common to both sites, four species had similar values of delta13C at the two sites despite the differences in rainfall, whereas in others the values of delta13C were significantly (P < 0.001) lower (more negative) at the wet than at the dry site. The SLA and nitrogen content per unit leaf area also differed significantly among the species (P < 0.001), but there was not a common relationship between delta13C and SLA or between delta13C and nitrogen content at the two sites. The strong species by environment interaction resulted from some species demonstrating phenotypic plasticity for delta13C, while others were inherently stable across environments.
Publisher: Springer Science and Business Media LLC
Date: 12-1983
DOI: 10.1007/BF00389645
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/FP16082
Abstract: Modern hexaploid wheat has several diploid and tetraploid predecessors. Morpho-physiological adaptation and the adaptation to drought of these different ploidy wheat species is largely unknown. To investigate the adaptation to drought stress, eight accesssions (two wild diploid (2n) accessions of Aegilops tauschii Coss., two domesticated diploid (2n) accessions of Triticum monococcum L., two domesticated tetraploid (4n) accessions of Triticum dicoccum Schrank ex Schübl. and two domesticated hexaploid (6n) accessions of Triticum aestivum L.) were exposed to three water regimes: (i) well-watered control (WW, 80% field capacity (FC)), (ii) moderate water stress (MS, 50% FC), and (iii) severe water stress (SS, 25% FC) from 30 days after sowing to maturity. The results showed that accession (A), water regime (W), and the interaction of A × W significantly affected yield, morpho-physiological traits, biochemical characteristics and biomass allocation. In the WW treatment, the aboveground biomass, ear biomass, grain yield and harvest index increased, whereas the number of spikes and spikelets per plant decreased from accessions of T. monococcum to T. dicoccum to T. aestivum. Across all accessions, yields decreased by 29% under moderate water stress and 61% under severe water stress. In all three water regimes, yields were positively correlated with photosynthesis (Pn) per plant (Pn × leaf area) at jointing and anthesis, largely the result of the differences and changes in leaf area. Water use efficiency for grain (WUEG) decreased by 2–6% in T. monococcum, but it increased by 15–16% in T. dicoccum and T. aestivum under drought stress. Analysis of the allometric relationships between aboveground biomass (MAB) and root biomass (Mroot) in the different species indicated that less biomass was allocated to roots with greater polyploidy while more biomass was allocated to roots with drought in A. tauschii, but not in the domesticated species. We conclude that domestication, selection and breeding of higher ploidy wheat has increased wheat yields primarily by increasing aboveground biomass and harvest index, increases that were maintained under water stress.
Publisher: Springer Science and Business Media LLC
Date: 02-1985
DOI: 10.1007/BF00378908
Publisher: Elsevier BV
Date: 04-2016
Publisher: Oxford University Press (OUP)
Date: 03-2013
Abstract: Predawn leaf water potential (LWP), the LWP between 09:00 and 10:30 h (termed minimum LWP), stem xylem hydraulic conductivity, foliar nitrogen, leaf gas exchange and leaf traits were measured on the same days in adults and 1-year-old to 7-year-old resprouts that had regrown after removing all the aboveground shoots. Height growth and accumulation of aboveground biomass quickly decreased with resprout age and there was no difference between 7-year-old resprouts and the uncut adults. Predawn LWP showed no significant difference between resprouts and adults, but the minimum LWP decreased gradually from -2.0 MPa in 1-year-old resprouts to -3.0 MPa in 7-year-old resprouts. The decrease in minimum LWP was associated with increased hydraulic resistance, as indicated by the gradual decrease in leaf area-specific hydraulic conductivity (KL) and sapwood area-specific hydraulic conductivity (KS) and the associated increase in stem native percentage loss of hydraulic conductivity in older than 2-year-old resprouts. The leaf nitrogen content per unit area (Narea) also decreased steadily from 3.6 g m(-2) in 1-year-old resprouts to 1.7 g m(-2) in 7-year-old resprouts. With the decline in LWP and Narea, the rate of leaf photosynthesis per unit area (Aarea) decreased from 20 μ mol m(-2) s(-1) in 1-year-old resprouts to 11 μ mol m(-2) s(-1) in 7-year-old resprouts. In adults, although KS decreased further compared with 7-year-old resprouts, the minimum LWP, KL, Narea and the rate of photosynthesis increased by 0.3 MPa, 29, 34 and 23%, respectively. The results show that a progressive loss of stem hydraulic conductivity and a steady decrease in foliar nitrogen with age were associated with a decrease in the photosynthetic rate of Caragana korshinskii Kom. resprouts, possibly changing the allocation of photosynthetic assimilates and slowing resprout height growth.
Publisher: Springer Science and Business Media LLC
Date: 02-1978
DOI: 10.1007/BF02149914
Publisher: Springer Science and Business Media LLC
Date: 08-12-2013
Publisher: Wiley
Date: 2003
Publisher: Elsevier BV
Date: 11-2023
Publisher: Cambridge University Press (CUP)
Date: 12-2004
DOI: 10.1079/PGR200448
Abstract: Chickpea ( Cicer arietinum L.) is an important crop for developed as well as underdeveloped countries, especially those in the Indian sub-continent that contribute more than 60% to both the global area and global production. The harsh environmental conditions under which chickpeas are generally grown impose restrictions on the expression of genetic yield potential. In the present study, a number of different breeding approaches for the development of genotypes possessing multiple resistances to different biotic and abiotic stresses, coupled with enhanced productivity are reported. In one study, 90 genetically erse genotypes (35 medium-sized desi types, 35 bold-seeded desi types, 10 medium-sized kabuli types and 10 bold-seeded kabuli types) were tested in several locations in the 2000–2002 seasons, under rainfed (dryland) conditions and with supplemental irrigation. The bold-seeded desi genotypes gave superior performance in the rainfed environment, while the bold-seeded kabuli genotypes outyielded the other cultivars under supplemental irrigation. From crosses between accessions from geographically erse sources, crosses between lines carrying multiple disease resistances, and crosses between the cultivated chickpea and the wild species, C. reticulatum , 23 selections were tested for yield and resistance to multiple stresses at various locations in northern and central India. From the crosses between geographically erse parents, six high-yielding kabuli genotypes with wide adaptation and drought tolerance were identified. Pyramiding genes for multiple resistances proved useful in identifying eight lines possessing multiple disease resistance. Introgressing wild genes generated nine genotypes with high yield potential, resistance to soil-borne diseases and adaptation to water-limited environments. We conclude that high productivity, multiple resistance and wide adaptability can be achieved simultaneously by using potentially complementary approaches.
Publisher: Elsevier BV
Date: 10-2007
Publisher: Springer Science and Business Media LLC
Date: 09-05-2012
Publisher: Springer Science and Business Media LLC
Date: 10-1979
DOI: 10.1007/BF02181885
Publisher: Springer Berlin Heidelberg
Date: 2013
Publisher: CSIRO Publishing
Date: 2003
DOI: 10.1071/AR02127
Abstract: To determine the influence of reduced irrigation input, carrot (Daucus carota L. cv. Ivor) plants were grown on a coarse-textured, sandy soil during summer near Perth, Western Australia. Irrigation was applied daily with sprinklers at 5 rates ranging from 47 to 151% replacement of daily pan evaporation (Ep). A reduction in irrigation from the industry standard of 151% Ep to 124 or 97% Ep resulted in a 17% increase in water use efficiency (WUE) when calculated as total root yield/water applied. However, the percentage of total roots that were marketable declined with reduction in irrigation, being 73, 56, and 63% at 151, 124, and 97% Ep, respectively. This minimised any increase in WUE when calculated on a marketable yield basis. Further reductions in irrigation to 47 and 73% Ep resulted in large reductions in yield, WUE, and the percentage of marketable roots. Leaf biomass was not significantly different between the 151 and 124% Ep treatments and was reduced by 55 and 85% at 73 and 47% Ep, respectively. Soil water tension (ψs) varied from 4 to 80 kPa among the irrigation treatments. Pre-dawn leaf water potential (ψl) was most sensitive to ψs over a ψs range of 0–20 kPa and the influence of ψs on ψl was small (400 kPa) compared with the diurnal variations in ψl of up to 1400 kPa, which occurred independently of significant changes in bulk soil ψs. There was no significant effect of irrigation on the osmotic potential of leaf sap and there was no evidence of osmotic adjustment. For all irrigation treatments, photosynthesis (Pn) peaked in the early morning (0830 hours) at rates of 17–20 μmol CO2/m2.s, after which Pn decreased to a transient minimum value at midday. The diurnal decline in Pn was positively correlated with ψl for all treatments, and minimum values of Pn varied from 12.5 to 7.8 μmol CO2/m2.s for plants grown with 151 and 47% of Ep, respectively. When grown under frequently applied, suboptimal irrigation, carrot productivity is predominately limited by a reduction in leaf growth rates that limits leaf area and matches transpiration requirements with water availability. Furthermore, even under conditions of water deficit, the aerial environment imposes a greater constraint to Pn than soil water availability.
Publisher: Springer Science and Business Media LLC
Date: 03-1983
DOI: 10.1007/BF00379555
Publisher: Springer Science and Business Media LLC
Date: 22-05-2017
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/AR05076
Abstract: Mediterranean environments are characterised by hot, dry summers and cool, wet winters. The native vegetation in Mediterranean-climatic regions is predominantly perennial shrubs and trees intermixed with annual forbs. In south-western Australia, the spread of agriculture has seen the well adapted perennial vegetation replaced by rainfed annual crops and pastures. This has increased waterlogging and secondary salinity, thereby causing loss of productivity in ~10% of the cleared land area. To reduce deep drainage and make the agricultural systems environmentally sustainable requires the re-introduction of perennial vegetation in the form of belts of trees or shrubs, and phase-farming systems with perennials such as lucerne replacing annual pastures between the cropping years. To be economically viable, agricultural productivity needs to increase by at least 3% per annum. Yields of dryland wheat, the predominant crop in the Mediterranean agricultural regions of Australia, have increased at ~1%/year for the century preceding the 1980s and since then by nearly 4%/year. Increases have arisen from both genotypic and agronomic improvements. Genotypic increases have arisen from selection for earliness, early vigour, deep roots, osmotic adjustment, increased transpiration efficiency, improved disease resistance, and an improved harvest index from high ear weight (grain number) at flowering and high assimilate storage and remobilisation. Agronomic increases have arisen from early sowing that has been enabled by minimum tillage, increased fertiliser use, especially nitrogen, weed control, and rotations to improve weed control, minimise disease risk, and increase nitrogen availability. Evidence is presented suggesting that the rapid increase in yield of wheat in the last two decades has likely arisen from the rapid adoption of new technologies. For productivity to be maintained in the face of the increasing requirement to be environmentally sustainable will be a challenge and will require better integration of breeding and agronomy.
Publisher: Oxford University Press (OUP)
Date: 04-1996
Publisher: Wiley
Date: 04-2007
Publisher: Oxford University Press (OUP)
Date: 16-07-2004
DOI: 10.1093/JXB/ERH190
Publisher: Wiley
Date: 16-10-2014
DOI: 10.1111/JAC.12103
Publisher: Wiley
Date: 10-10-2014
DOI: 10.1111/JAC.12102
Publisher: Wiley
Date: 19-11-2015
DOI: 10.1111/JAC.12107
Publisher: Springer Science and Business Media LLC
Date: 04-1984
DOI: 10.1007/BF00377364
Publisher: Oxford University Press (OUP)
Date: 1976
Publisher: Springer Science and Business Media LLC
Date: 20-04-2020
DOI: 10.1038/S41591-020-0807-6
Abstract: A double burden of malnutrition occurs when in iduals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4% (62.3 (55.1–70.8) million) to 6.4% (58.3 (47.6–70.7) million), but is predicted to remain above the World Health Organization’s Global Nutrition Target of % in over half of LMICs by 2025. Prevalence of overweight increased from 5.2% (30 (22.8–38.5) million) in 2000 to 6.0% (55.5 (44.8–67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic.
Publisher: Wiley
Date: 02-1984
Publisher: Springer Science and Business Media LLC
Date: 30-09-2021
DOI: 10.1038/S41597-021-01006-6
Abstract: We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field c aigns, published literature, taxonomic monographs, and in idual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised in idual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other national or regional initiatives globally to fill persistent gaps in trait knowledge.
Publisher: CSIRO Publishing
Date: 2000
DOI: 10.1071/AR00037
Abstract: Two carrot (Daucus carota L.) genotypes (Nantes and Imperator) were grown in the field on a coarse-textured, sandy soil. Experiments were conducted over 2 consecutive seasons, one providing cool growing conditions and the other much warmer growing conditions during which the vapour pressure deficit was up to 2-fold higher than in the first season. Changes in growth, soil water content, and environmental conditions were monitored for both seasons, and diurnal measurements of leaf water potential and leaf photosynthesis were taken near maturity. Frequent irrigation maintained bulk soil water content above, or near, field capacity, with the sum of rainfall and irrigation exceeding potential evaporation by 1.4- and 1.3-fold during the cool and warm seasons, respectively. Even under such well-watered conditions, a large diurnal variation in leaf water potential (1200 and 1800 kPa for the cool- and warm-season crops, respectively) was recorded. During the cool season, withholding irrigation for up to 60 h resulted in further reductions in midday leaf water potential. However, there was no effect of withholding irrigation on leaf water potential during the warm season. During both seasons, leaf photosynthetic rate of well-watered plants peaked at around 20 µmol/m2.s in the early morning (0900 hours) and then decreased throughout the day, with the magnitude of the decline associated with the prevailing vapour pressure deficit. Under well-watered conditions, leaf water potential and photosynthesis were both negatively correlated with vapour pressure deficit, for both genotypes. Leaf water potential and photosynthesis were positively correlated with each other and we conclude that a high hydraulic resistance in the plant or soil results in a vapour pressure deficit-induced reduction in leaf water potential, which in turn reduces the rate of leaf photosynthesis.
Publisher: Elsevier BV
Date: 05-1998
Publisher: Springer Science and Business Media LLC
Date: 09-1969
DOI: 10.1038/2231070A0
Publisher: Elsevier BV
Date: 09-2018
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 11-2010
Publisher: American Association for the Advancement of Science (AAAS)
Date: 2019
Abstract: Oilseed Brassica species are vulnerable to heat and drought stress, especially in the early reproductive stage. We evaluated plant imaging of whole plant and flower tissue, leaf stomatal conductance, leaf and bud temperature, photochemical reflectance index, quantum yield of photosynthesis, and leaf gas exchange for their suitability to detect tolerance to heat (H) and/or drought (D) stress treatments in 12 Brassica genotypes (G). A replicated factorial experiment was set up with 7 d of stress treatment from the beginning of anthesis with various levels of three factors H , D , and G . Most phenomics tools detected plant stress as indicated by significant main effects of H , D , and H×D . Whole plant volume was highly correlated with fresh weight changes, suggesting that whole plant imaging may be a useful surrogate for fresh weight in future studies. Vc max , the maximum carboxylation rate of photosynthesis, increased rapidly on day 1 in H and H+D treatments, and there were significant interactions of G×H and G×D . Vc max of genotypes on day 1 in H and H+D treatments was positively correlated with their harvested seed yield. Vc max on day 1 and day 3 were clustered with seed yield in H and H+D treatments as shown in the heatmaps of genotypic correlations. TPU, the rate of triose phosphate use, also showed significant positive genotypic correlations with seed yield in H+D treatments. Flower volume showed significant interactions of G×H and G×D on day 7, and flower volume of genotypes on day 7 in H was positively correlated with their harvested seed yield. There were few interactions of G×H or G×D for leaf stomatal conductance, leaf and bud temperature, photochemical reflectance index, and quantum yield of photosynthesis. Vc max , TPU, and volume of flowers are potential nondestructive phenomic traits for heat or combined heat and drought stress tolerance screening in Brassica germplasm.
Publisher: Elsevier BV
Date: 12-1995
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/FP13340
Abstract: High temperatures and decreased rainfall are detrimental to yield in chickpea (Cicer arietinum L.), particularly during grain filling. This study aimed to (i) assess the in idual and combined effects of drought and heat stress on biochemical seed-filling processes, (ii) determine genotypic differences in heat and drought tolerance, and (iii) determine any cross-tolerance. Plants were grown outdoors in the normal growing season when temperatures during seed filling were −20°C or were planted late (temperatures −20°C heat stress). Half of the pots were kept adequately watered throughout, but water was withheld from the others from the initiation of seed filling until the relative leaf water content reached 50% of the irrigated plants (drought stress) all plants were rewatered thereafter until seed maturit. Water was withheld for 13 days (normal sowing) and 7 days (late sowing), so soil moisture decreased by 54–57%. Tests on leaves and seeds were performed after the stress. In idual and combined stress damaged membranes, and decreased cellular oxidising ability, stomatal conductance, PSII function and leaf chlorophyll content damage was greater under combined stress. Leaf Rubisco activity increased with heat stress, decreased with drought stress and decreased severely with combined stress. Sucrose and starch concentrations decreased in all seeds through reductions in biosynthetic enzymes reductions were greater under combined stress. These effects were more severe in heat- and drought-sensitive genotypes compared with drought-tolerant genotypes. Drought stress had a greater effect than heat stress on yield and the biochemical seed-filling mechanisms. Drought- and heat-tolerant genotypes showed partial cross-tolerance.
Publisher: No publisher found
Date: 2011
Publisher: Institute of Experimental Botany
Date: 31-12-1999
Publisher: Oxford University Press (OUP)
Date: 05-2000
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/FP12250
Abstract: The effect of soil drenching with 10 µM abscisic acid (ABA) on the physiological responses of two spring wheat (Triticum aestivum L.) cultivars released in different decades was evaluated when subjected to a water deficit at jointing or at booting. Exogenous ABA application increased the ABA concentration in the leaves, reduced the stomatal conductance (gs), slowed the rate of water use, decreased the lethal leaf water potential (ψ) used to measure desiccation tolerance and lowered the soil water content (SWC) at which leaf relative water content (RWC) began to decrease and wilting was observed. Exogenous ABA application also reduced reactive oxygen species (ROS) formation and increased antioxidant enzyme activity, leading to a reduction in the oxidative damage to lipid membranes in both cultivars exposed to water stress at jointing and booting. The decrease in leaf RWC and wilting occurred at lower values of SWC in the recently-released cultivar than in the earlier-released cultivar. The recently-released cultivar also had higher grain yield than the earlier-released cultivar at moderate water stress, but the grain yield in both cultivars was reduced by water stress and by the exogenous ABA treatment. However, exogenous ABA treatment increased transpiration efficiency for grain (TEG) of both cultivars under moderate water stress. These results indicate that ABA played an important role in slowing water use and enhancing the antioxidant defence during soil drying, but this did not result in increased yields under drought stress.
Publisher: Elsevier BV
Date: 04-2006
Publisher: Oxford University Press (OUP)
Date: 04-2006
DOI: 10.1093/TREEPHYS/26.4.479
Abstract: Leaves and s les of recent wood of Eucalyptus species were collected along a rainfall gradient parallel to the coast of Western Australia between Perth in the north and Walpole in the south and along a southwest to northeast transect from Walpole in southwestern Australia, to near Mount Olga in central Australia. The collection included 65 species of Eucalyptus s led at 73 sites and many of the species were collected at several sites along the rainfall gradient. Specific leaf area (SLA) and isotopic ratio of 13C to 12C (delta 13C) of leaves that grew in 2002, and tree ring growth and delta 13C of in idual cell layers of the wood were measured. Rainfall data were obtained from the Australian Bureau of Meteorology for 29 locations that represented one or a few closely located collection sites. Site-averaged data and species-specific values of delta 13C decreased with decreasing annual rainfall between 1200 and 300 mm at a rate of 1.63 per thousand per 1000 mm decrease in rainfall. Responses became variable in the low rainfall region ( 300 mm of annual rainfall. Specific leaf area varied between 2 and 6 m2 kg(-1) and tended to increase with decreasing annual rainfall in some species, but not all, whereas delta 13C decreased with SLA. The relationship between delta 13C and SLA was highly species and soil-type specific. Leaf-area-based nitrogen (N) content varied between 2 and almost 6 g m(-2) and decreased with rainfall. Thus, thicker leaves were associated with higher N content and this compensated for the effect of drought on delta 13C. Nitrogen content was also related to soil type and species identity. Based on a linear mixed model, statistical analysis of the whole data set showed that 27% of the variation in delta 13C was associated with changes in SLA, 16% with soil type and only 1% with rainfall. Additionally, 21% was associated with species identity. For a subset of sites with > 300 mm rainfall, 43% of the variation was explained by SLA, 13% by soil type and only 3% by rainfall. The species effect decreased to 9% because there were fewer species in the subset of sites. The small effect of rainfall on delta 13C was further supported by a path analysis that yielded a standardized path coefficient of 0.38 for the effect of rainfall on SLA and -0.50 for the effect of SLA on delta 13C, but an insignificantly low standardized path coefficient of -0.05 for the direct effect of rainfall on delta 13C. Thus, in contrast to our hypothesis that delta 13C decreases with rainfall independent of soil type and species, we detected no statistically significant relationship between rainfall and delta 13C in leaves of trees growing at sites receiving < 300 mm of rainfall annually. Rainfall affected delta 13C indirectly through soil type (a surrogate for water-holding capacity) across the rainfall gradient. Annual tree rings are not clearly visible in evergreen Eucalyptus species, even in the seasonally cool climate of SW Australia. Generally, visible density transitions in the wood are related not to a strict annual cycle but to periods of growth associated mainly with rainfall. The relationship between delta 13C of leaves and the width of these stem increments was not statistically significant. Analysis of stem growth periods showed that delta 13C in wood responded to rainfall events, but carbohydrate storage and reallocation also affected the isotopic signature. Although delta 13C in wood of any one species varied over a range of 2 to 4 per thousand, there was a general relationship between delta 13C of the leaves and the annual range of delta 13C in wood. We conclude that species-specific traits are important in understanding the response of Eucalyptus to rainfall and that the ersity of the genus may reflect its response to the large climatic gradient in Australia and to the large annual and interannual variations in rainfall at any one location.
Publisher: Springer Science and Business Media LLC
Date: 08-1974
DOI: 10.1038/250486A0
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/AR05170
Abstract: The growth and yield of spring wheat (Triticum aestivum L.) were examined to determine the actual and potential yields of wheat at a site in the high rainfall zone (HRZ) of south-western Australia. Spring wheat achieved yields of 5.5−5.9 t/ha in 2001 and 2003 when subsurface waterlogging was absent or minimal. These yields were close to the estimated potential, indicating that a high yield potential is achievable. In 2002 when subsurface waterlogging occurred early in the growing season, the yield of spring wheat was 40% lower than the estimated potential. The yield of wheat was significantly correlated with the number of ears per m2 (r2 = 0.81) and dry matter at anthesis (r2 = 0.73). To achieve 5–6 t/ha of yield of wheat in the HRZ, 450–550 ears per m2 and 10–11 t/ha dry matter at anthesis should be targetted. Attaining such a level of dry matter at anthesis did not have a negative effect on dry-matter accumulation during the post-anthesis period. The harvest index (0.36−0.38) of spring wheat was comparable with that in drier parts of south-western Australia, but relatively low given the high rainfall and the long growing season. This relatively low harvest index indicates that the selected cultivar bred for the low- and medium-rainfall zone in this study, when grown in the HRZ, may have genetic limitations in sink capacity arising from the low grain number per ear. We suggest that the yield of wheat in the HRZ may be increased further by increasing the sink capacity by increasing the number of grains per ear.
Publisher: Springer Science and Business Media LLC
Date: 1984
DOI: 10.1007/BF00390662
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/AR05050
Abstract: Nineteen erse lentil genotypes, 8 originating from South Asia, 6 from West Asia, and 5 crossbreds using parents from South Asia and West Asia (or other Mediterranean environments), were evaluated for growth, phenology, yield, and yield components at Khumaltar in the mid-hill region of Nepal. Additionally, dry matter production, partitioning, root growth and water use of 8 selected genotypes from the 3 groups were measured at key phenological stages. The seed yield of the West Asian genotypes was only 330 kg/ha, whereas the South Asian genotypes produced a mean seed yield of 1270 kg/ha. The crossbreds had a significantly (P = 0.05) greater seed yield (1550 kg/ha) than the South Asian genotypes. The high seed yield of both the South Asian and crossbred genotypes was associated with rapid ground cover, early flowering and maturity, a long reproductive period, a greater number of seeds and pods, high total dry matter, greater harvest index, and high water use efficiency. West Asian genotypes, on the other hand, flowered 43 days later, matured 15 days later, and had a shorter reproductive period (by 22 days) than the crossbred and South Asian genotypes. The 23% greater seed yield in the crossbreds compared with the South Asian genotypes was the result of a similar increase in seed size (weight per seed). There were no significant differences in total root length (mean 4.7 km/m2), root dry matter (mean 95.5 g/m2), or water use among the 3 groups during the major part of the growing period. There was a significant difference in total water use due to the longer growing season of the West Asian genotype ILL 7983 and its ability to use late-season rainfall. Maximum water use efficiencies for seed yield of 7.0 kg/ha.mm and for above-ground dry matter of 18.9 kg/ha.mm were comparable with those reported in India and the Mediterranean environments of south-western Australia and Syria.
Publisher: Elsevier BV
Date: 11-1999
Publisher: Springer Netherlands
Date: 2011
Publisher: CSIRO Publishing
Date: 1991
DOI: 10.1071/AR9910471
Abstract: lrrigation treatments were imposed in the field on an indeterminate cultivar of narrow-leafed lupins (Lupinus angustifolius L., cv. Danja) and on a breeding line with reduced branching (75A/329) so that they experienced no water-deficits (frequently irrigated), a transient mild water-deficit or a transient severe water-deficit during early reproductive growth, or continuous severe water-deficit during reproductive growth (unirrigated). Both leaf water potential and leaf conductance declined in all treatments in which a water-deficit was imposed. Differences in leaf conductance were apparent before differences in leaf water potential: conductance declined to 40% and 30% of the frequently irrigated controls in the transient mild and severe water-deficit treatments, respectively. Leaf water potential declined to -1 - 1 MPa and -1.6 MPa, respectively, in the transient mild and severe water-deficit treatments, compared to between -0 - 65 and -0 - 95 MPa for the frequently irrigated controls. Seed yield and total dry weight were reduced in the transient severe water-deficit and unirrigated treatments, but were no different from the frequently irrigated treatment when the water-deficit was transient and mild. However both transient water-deficit treatments produced more main-stem seed yield than the frequently irrigated treatment, especially in the reduced-branching line 75A/329. The transient mild water-deficit treatment also produced more first-order apical axis yield than the frequently irrigated treatment. These yield increases were mainly due to a greater yield of seed per pod, although on the first-order apical axes there was also a tendency to set more pods. The greater seed yield per pod in the transient water-deficit treatments was due to an apparent redirection of assimilate from vegetative to reproductive growth. This was not due to a smaller reduction in reproductive growth rates than in vegetative growth rates, but to an acceleration of reproductive growth that was maintained after stress relief. The same early acceleration of reproductive growth was also observed in unirrigated treatments, but the severe stress which persisted throughout later reproductive growth reduced pod growth rates and negated the early advantage.
Publisher: Cambridge University Press (CUP)
Date: 12-2006
DOI: 10.1079/PGR2006123
Abstract: A chickpea collection of 1600 desi and 1400 kabuli were evaluated for yield losses arising from pod borer ( Helicoverpa armigera ) infestation under rainfed conditions by spraying half the plots to prevent pod borer infestation and allowing the other half to be infested. From these lines, 82 were selected for further detailed evaluation of Helicoverpa resistance and drought resistance under irrigated and rainfed conditions. The yield losses from Helicoverpa damage varied from 10 to 33% depending on the chickpea type and the growing environment. Spreading types were more susceptible to Helicoverpa damage than erect types, as were kabuli types compared to desi types. Yield losses due to Helicoverpa infestation were always greater in the irrigated than in the rainfed materials. Terminal drought reduced yields by 13–37% depending on plant type. The yields in the kabuli c“hickpea lines were more severely reduced than were the desi types, due to a greater reduction in the number of branches and pods per plant in the kabuli compared to the desi lines. It appears that the extent of pod borer damage varies between the chickpea types, and that desi types have greater drought resistance than kabuli ones. These characteristics should be informative for the population improvement of chickpea for environments in which terminal drought and Helicoverpa damage occur frequently.
Publisher: Oxford University Press (OUP)
Date: 15-05-2018
DOI: 10.1093/JXB/ERY181
Abstract: Osmotic adjustment (OA), the accumulation of solutes in higher plant cells in response to water deficits, was first reported more than four decades ago. Since then, variation in OA among genotypes/cultivars in response to drought has been reported in many crop plants, but its role in maintaining growth and yield in water-limited environments has been questioned. The role of OA in the physiological and agronomic adaptation to water stress of crops, the methods of reliably measuring the degree of OA among genotypes or species, the range of OA in many studies, and its impact on grain yield in water-limited environments are reviewed. The genetics of OA has received limited study, and the breeding and selection for high OA has only resulted in the release of one commercial cultivar of wheat as far as is known. The reasons for the limited interest in breeding for the OA trait are discussed.
Publisher: Wiley
Date: 16-11-2016
DOI: 10.1111/PCE.12839
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 04-2011
End Date: 12-2013
Amount: $200,000.00
Funder: Australian Research Council
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