Investment

Heat stress is a significant constraint to wheat yield potential and the frequency of occurrence and intensity is projected to increase with climate change. Australian grain growers mitigate the impacts of heat stress by optimising sowing time when possible, input use and variety choice to avoid both frost and heat stress induced loss of yield. Improved heat tolerance of wheat varieties would give grain growers more flexibility while maintaining yield potential in a warmer climate.

Heat stress causes significant damage during floral development and grain filling. Heat stress during floral development reduces grain number through pollen sterility and floret abortion and heat stress during grain filling reduces grain size. Both impact eventual yield and grain quality. However, in Australia, grain filling heat stress occurs more frequently and thus has a larger impact on wheat yields. This collaborative project will deliver new pre-breeding lines with at least 10% higher yield than the current highest yielding cultivars under heat stress during grain filling. These new lines will be enriched for heat tolerance at grain filling and delivered to wheat breeders with genomic information to aid selection and incorporation of tolerance into new varieties.

Heat tolerance will be confirmed and validated at up to 40 sites nationally, including 5 key locations representative of the wider Australian wheat belt. A suite of genomic tools will assist InterGrain with integration of this new diversity into market-ready varieties. New enhanced materials will be developed using genomic selection and rapid generation advance. The new genetics for superior heat tolerance will be integrated into InterGrain's breeding pipeline. All new materials developed by the project with enhanced GEBVs for heat tolerance during grain filling - but outside the immediate InterGrain breeding pipeline - will be available to all commercial entities and researchers two years after validation.