ORCID Profile
0000-0002-0247-4037
Current Organisation
CSIRO Black Mountain Laboratories
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Oxford University Press (OUP)
Date: 30-05-2019
DOI: 10.1093/JXB/ERZ257
Abstract: The high temperature responses of photosynthesis and respiration in wheat are an underexamined, yet potential avenue to improving heat tolerance and avoiding yield losses in a warming climate.
Publisher: Oxford University Press (OUP)
Date: 18-10-2020
DOI: 10.1093/JXB/ERAA481
Abstract: Gibberellin (GA)-insensitive dwarfing genes Rht-B1b and Rht-D1b that are responsible for the ‘Green Revolution’ have been remarkably successful in wheat improvement globally. However, these alleles result in shorter coleoptiles and reduced vigour, and hence poor establishment and growth in some environments. Rht18, on the other hand, is a GA-sensitive, dominant gene with potential to overcome some of the early growth limitations associated with Rht-B1b and Rht-D1b. We assessed progeny from both a biparental and a backcross population that contained tall, single dwarf, and double dwarf lines, to determine whether Rht18 differs from Rht-D1b and hence verify its value in wheat improvement. Progeny with Rht18 had an almost identical height to lines with Rht-D1b, and both were ~26% shorter than the tall lines, with the double dwarf 13% shorter again. However, coleoptile length of Rht18 was 42% longer than that of Rht-D1b. We detected no differences in time to terminal spikelet and anthesis, and few differences in stem or spike growth. Both dwarfing genes erted more dry matter to the spike than tall lines from prior to heading. No differences were detected between Rht18 and Rht-D1b that could prevent the adoption of Rht18 in wheat breeding to overcome some of the limitations associated with the ‘Green Revolution’ genes.
Publisher: Wiley
Date: 11-01-2021
DOI: 10.1111/PCE.13971
Abstract: Climate change and future warming will significantly affect crop yield. The capacity of crops to dynamically adjust physiological processes (i.e., acclimate) to warming might improve overall performance. Understanding and quantifying the degree of acclimation in field crops could ensure better parameterization of crop and Earth System models and predictions of crop performance. We hypothesized that for field‐grown wheat, when measured at a common temperature (25°C), crops grown under warmer conditions would exhibit acclimation, leading to enhanced crop performance and yield. Acclimation was defined as (a) decreased rates of net photosynthesis at 25°C ( A 25 ) coupled with lower maximum carboxylation capacity ( V cmax 25 ), (b) reduced leaf dark respiration at 25°C (both in terms of O 2 consumption R dark _O 2 25 and CO 2 efflux R dark _CO 2 25 ) and (c) lower R dark _CO 2 25 to V cmax 25 ratio. Field experiments were conducted over two seasons with 20 wheat genotypes, sown at three different planting dates, to test these hypotheses. Leaf‐level CO 2 ‐based traits ( A 25 , R dark _CO 2 25 and V cmax 25 ) did not show the classic acclimation responses that we hypothesized by contrast, the hypothesized changes in R dark_ O 2 were observed. These findings have implications for predictive crop models that assume similar temperature response among these physiological processes and for predictions of crop performance in a future warmer world.
Publisher: Oxford University Press (OUP)
Date: 14-05-2019
DOI: 10.1093/JXB/ERZ232
Abstract: Rooting depth, a hard trait to measure in the field, was negatively correlated with canopy temperature, an easy trait to measure by airborne thermography, in large wheat populations under terminal drought
Publisher: Oxford University Press (OUP)
Date: 29-04-2020
DOI: 10.1093/JXB/ERAA201
Abstract: Using a field to lab approach, mature deep-rooting traits in wheat were correlated to root phenotypes measured on young plants from controlled conditions. Mature deep-rooting root traits of 20 wheat genotypes at maturity were established via coring in three field trials across 2 years. Field traits were correlated to phenotypes expressed by the 20 genotypes after growth in four commonly used lab screens: (i) soil tubes for root emergence, elongation, length, and branching at four ages to 34 days after sowing (DAS) (ii) paper pouches 7 DAS and (iii) agar chambers for primary root (PR) number and angles at 8 DAS and (iv) soil baskets for PR and nodal root (NR) number and angle at 42 DAS. Correlations between lab and field root traits (r2=0.45–0.73) were highly inconsistent, with many traits uncorrelated and no one lab phenotype correlating similarly across three field experiments. Phenotypes most positively associated with deep field roots were: longest PR and NR axiles from the soil tube screen at 20 DAS and narrow PR angle and wide NR angle from soil baskets at 42 DAS. Paper and agar PR angles were positively and significantly correlated to each other, but only wide outer PRs in the paper screen correlated positively to shallower field root traits. NR phenotypes in soil baskets were not predicted by PR phenotypes in any screen, suggesting independent developmental controls and value in measuring both root types in lab screens. Strong temporal and edaphic effects on mature root traits, and a lack of understanding of root trait changes during plant development, are major challenges in creating controlled-environment root screens for mature root traits in the field.
No related grants have been discovered for Richard Richards.