Genetic Variability and Association Analysis in US Soft Wheat Panel for Fruiting Efficiency Under Post Anthesis Drought and Supplemental Irrigated Conditions.

Genetic progress in wheat yield under drought conditions is deemed to be slower as compared to high yielding environments. Drought stress is one of the major yield limiting factor in the USA and other wheat growing regions globally. Future improvement in wheat yield could potentially be achieved by the combination of different noble traits associated with improving harvest index or partitioning of useful biomass towards sink, such as fruiting efficiency (grains set per unit of spike dry weight). To accomplish the goal of higher grain yield in wheat, we need to develop ideotype with improved spike partitioning of assimilates during post anthesis stage. We characterized 260 diverse soft wheat genotypes (developed by Southeastern University Grains consortium) for fruiting efficiency, harvest index, yield and yield related components, and a subset of germplasm for spike partitioning traits under post anthesis drought and supplemental irrigated conditions. Preliminary data demonstrated significant genetic variation for fruiting efficiency, grain numbers, harvest index, yield, and related components.  This research will identify loci associated with spike fertility related traits in the panel through genome wide association mapping. The final results will support in identifying genotypes with better fruiting efficiency, grain number and harvest index which will be a valuable source for future genetic improvement of grain yield.