Ground Cover Supplement : GC Supplement - Wheat pre-breeding
12 GROUNDCOVER Issue 127 | March – April 2017 | GRDC GROUNDCOVERTM SUPPLEMENT: WHEAT PRE-BREEDING YIELD STABILITY Wheat root traits for water-limited environments Australia is a drought-prone continent, so improving crop adaptation to water-limited environments is a major breeding target By Dr Jack Christopher n A novel combination of technologies has been developed to accelerate breeding wheat with greater resilience to dry conditions in a GRDC project led by researchers at the University of Queensland (UQ) and the Queensland Alliance for Agriculture and Food Innovation (QAAFI) – a collaboration between UQ and the Queensland Department of Agriculture and Fisheries. The project targets root architecture and the stay-green trait – the ability of plants to retain green leaf area after flowering and therefore ‘stay green’ – that have been associated with improved yield, particularly under water limitation. An innovative approach is being used that was recently successfully applied to sorghum improvement. The breeding strategy can identify the genetic control of complex traits and enable the development of improved, elite ger mplasm. STAY-GREEN The project team has developed a new method to objectively characterise novel stay-green traits for hundreds of genotypes in standard field trial plots using a hand- held sensor (Figure 1) and a novel way to model data. The new approach has greatly improved the ability to compare traits for genotypes with small differences in flowering date. It also allows more confident comparisons between genotypes tested at multiple sites or in multiple seasons. Using crop simulation modelling by Dr Karine Chenu, the value of these traits has been evaluated in a range of Australian cropping environments. We anticipate increased automation of sensing methods using ground-based or aerial vehicles will allow these techniques to be more widely applied in breeding programs in the future. ROOT ARCHITECTURE Novel phenotyping techniques and crop modelling are also making it possible to manipulate root-system architecture traits to better understand their impact on yield relative to climate conditions, including through the use of historical climate data for all major Australian cropping regions. These studies revealed that increased root- extractable water at depth can potentially improve productivity in parts of all Australian cropping regions and is rarely a disadvantage. With climate modellers predicting increased summer rainfall in many parts of Australia, FIGURE 1 A method has been developed to phenotype stay-green traits for hundreds of wheat genotypes in standard yield plots in the field. FAST FACTS n Wheat varieties better able to deal with water limitation are being developed faster using new technologies to select for stay-green traits and improved root systems. n Favourable root architecture and stay- green traits have been crossed into elite backgrounds from each major Australian cropping region. The resultant lines will be delivered to wheat breeders to produce high-yielding, stay-green cultivars with adaptive root traits for each region.
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