ORCID Profile
0000-0002-9799-5475
Current Organisation
Ceres Imaging (United States)
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Publisher: International Journal Of Advanced Research
Date: 31-03-2017
DOI: 10.21474/IJAR01/3511
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/CP19451
Abstract: Brassica tournefortii Gouan. (wild turnip, WT) has become a problematic weed in the no-till production systems of the northern grains region of Australia. Experiments were undertaken using different biotypes of B. tournefortii to examine its phenology, emergence and seedbank persistence. Biotypes were obtained from paddocks of barley (Hordeum vulgare L.) (WT1 and WT9) and chickpea (Cicer arietinum L.) (WT1/17 and WT2/17). Fresh seeds initially had high dormancy rates and persisted for a short period on the surface. Seedbank persistence increased with burial depth, with 39% of seeds remaining for WT1 and 5% for WT9 after 30 months at 2 cm depth. Persistence of buried seeds varied across biotypes WT1/17 seedlings also emerged in the second growing season from 2 cm depth. Compared with buried seeds, seedlings readily emerged from the surface (in March–June following increased rainfall) within 6 months of planting. Emergence was greatest on the surface and varied between biotypes and tillage systems the highest rate recorded was ~14%. Multiple cohorts were produced between February and October. No-till systems produced higher emergence rates than conventional tillage systems. Seedlings of B. tournefortii did not emerge from 5 cm soil depth therefore, diligent tillage practices without seedbank replenishment could rapidly reduce the presence of this weed. A soil-moisture study revealed that at 25% of water-holding capacity, B. tournefortii tended to produce sufficient seeds for reinfestation in the field. Brassica tournefortii is a cross-pollinated species, and its wider emergence time and capacity to produce enough seeds in a dry environment enable it to become widespread in Australia. Early cohorts (March) tended to have vigorous growth and high reproduction potential. This study found B. tournefortii to be a poor competitor of wheat (Triticum aestivum L.), having greater capacity to compete with the slow-growing crop chickpea. Therefore, control of early-season cohorts and use of rotations with a more vigorous crop such as wheat may reduce the seedbank. The information gained in this study will be important in developing better understanding of seed ecology of B. tournefortii for the purpose of developing integrated management strategies.
Publisher: Cambridge University Press (CUP)
Date: 19-04-2021
DOI: 10.1017/WSC.2021.30
Abstract: African mustard ( Brassica tournefortii Gouan) is a problematic winter annual weed in Australia. Germination ecology of B. tournefortii may change in response to the maternal environments or habitats in which the plants grow. A study was conducted to evaluate the effect of environmental factors on germination and emergence of four populations of B. tournefortii that were collected from different fields. Averaged over populations, germination was stimulated by dark and was higher at 25/15 C (92%) compared with 15/5 C (76%) and 35/25 C (45%). Averaged over light/dark regimes, at the lowest temperature regime (15/5 C), population A had higher germination than population D however, at the highest temperature regime (35/25 C), population D had higher germination than population A. Populations B and C had higher germination in the temperature range of 25/15 C and 30/20 C compared with 15/5 C, 20/10 C, and 35/25 C. Seeds germinated at a wide range of alternating day/night temperatures (15/5 to 35/25 C), suggesting that seeds can germinate throughout the year if other optimum conditions are available. Population A was more tolerant to water and salt stress than population D. The sodium chloride concentration and osmotic potential required to inhibit 50% germination of population A were 68 mM and −0.60 MPa, respectively. Averaged over populations, seeds placed at 1-cm soil depth had the highest emergence (54%), and burial depth of 8 cm resulted in 28% seedling emergence. Averaged over populations, wheat residue retention at 6,000 kg ha −1 resulted in greater seedling emergence than the residue amount of 1,000 kg ha −1 . The results suggest that B. tournefortii will be favored in no-till systems and that the seedbank of B. tournefortii could be managed by tillage regimes that bury its seeds below 8-cm depths and restrict seedling emergence and growth of new plants.
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