Genetic Improvement of Harvest Index and Stay-Green Traits in US Soft Wheat Germplasm Under High Temperature Stress Condition.

Rapid population growth and global climate change including elevated temperature are the two major agricultural challenges today that pose a threat of increased food insecurity in near future. The genetic progress of grain yield in wheat ranged from 0.3% to 1.0% per year during the last century, but must be doubled by 2050 to overcome these challenges. Wheat breeders must develop high yielding varieties that can withstand extreme weather conditions. The aim of this study is to identify and validate different traits associated with harvest index (spike fertility, gran filling rate, grain filling duration, yield and other yield related traits) and stay green characterstics (chlorophyll content, normalized difference vegetation index) in 248 US soft wheat panel under high temperature stressed location. Our preliminary data revealed strong genetic variations for all these traits. Our goal is to find unique alleles associated with these traits through genome-wide association analysis and utilize that information for genetic improvement for heat tolerance.