*Correspondence: rajeev.varshney@murdoch.edu.au

Wheat (Triticum aestivum L.) is the most prominently grown crop in the world that is pivotal in human nutrition. Its production requires at least ~2.5% annual increase by 2050 to meet the nutritional demands of the surging population. However, global warming and climate change gravely threaten wheat production worldwide, resulting in significant yield reductions.

Heat stress affects a plethora of physiological mechanisms in plants, such as photosynthesis, redox reactions, protein and starch synthesis, and source-sink translocation, leading to deterioration in grain quality and quantity. Adaptation to the climate scenarios of the future is critical to meet global food security in the coming years.

Assessing the genetic variation underlying the traits of interest is the key for such adaptation. With this preamble, our study aims to explore the variation, and identify the candidate genes and superior haplotypes associated with the heat tolerance-component traits in a panel of 345 diverse wheat genotypes which include cultivars and landraces.

One season field trial data in Northam, Western Australia depicted significant differences for all the traits among these genotypes. Days to flowering and flag leaf chlorophyll content had the most effect on biomass and grain yield. In the upcoming field trials, unmanned aerial vehicle (UAV)-mounted multispectral sensors will be used for high-throughput field phenotyping (HTFP) of staygreen and agronomic traits in timely and late-sown wheat to assess the genotypic heat stress response. Also, the effect of heat on fertilization will be quantified by spikelet fertility measurements.

Further, candidate genes and superior haplotypes associated with heat tolerance will be identified through genome-wide association studies (GWAS), followed by validation of the candidate genes using expression analysis and functional marker assays.

In essence, this study will not only identify superior heat tolerant genotypes possessing better staygreen character, spikelet fertility and yield, but also the markers underlying the heat tolerance-component traits, thus providing a resource base for the breeding industry in Australia and elsewhere in the world for developing climate-smart varieties for the future.