Genetic Variation for Spike Fertility and Yield Related Traits in Diverse US Soft Wheat Germplasm Under Post-Anthesis High Temperature Stress Condition.

The genetic progress of grain yield in wheat ranged from 0.3% to 1.0% per year during the last century, but has to be doubled to achieve global food demand for rising population in 2050. High temperature in particular is a serious threat to achieve that goal which alone can reduce the yield of wheat by as much as 15%. The annual occurrence of moderate heat stress, accompanied by periodic extreme heat stress events, prevents wheat from reaching its full potential yield in the USA. Wheat breeders must develop smart varieties that can withstand increasing climate change impacts with stable performance and are tolerated to extreme weather conditions. The aim of this study is to evaluate the genetic variations for spike fertility (SF), grain filling rate (GFR), grain filling duration (GFD), yield and yield related traits in a diverse US soft wheat panel (246 genotypes) under post anthesis heat stress conditions in two locations in Florida (Quincy and Citra). Our preliminary data revealed strong genetic variations for SF, GFR, GFD, number of grains/spike, grains/m², and yield. Our goal is to find unique alleles associated with those traits through genome-wide association analysis and utilize that information for genetic improvement for heat tolerance.