High temperature during reproductive development is a major problem to wheat production and end-use quality in the Southern Great Plains and to wheat production in many environments worldwide. We have initiated a project to integrate genotypic (QTL), phenotypic, and transcript level data to identify genes controlling reproductive stage heat tolerance in heat tolerant genotypes of wheat as it relates to yield and end-use quality maintenance. Efforts have initially focused on building recombinant inbred lines (RILs), mapping of QTL linked to reproductive stage heat tolerance, and development of cDNA libraries enriched, through suppressive subtractive hybridization, for genes induced by the heat stress. The selected tissues for library construction included wheat heads and flag leaves isolated from plants subjected to heat stress at 10 days after pollination. RILs were derived from a cross between heat tolerant spring wheat cv Halberd, and a susceptible winter wheat cv Cutter or cv Karl92. These parents were also used as models to define the two adaptive responses to heat stress (heat avoidance (susceptible) and heat tolerance). Over 1920 unique ESTs have been sequenced. These genes include some potential regulatory proteins, heat shock proteins, lipid-transfer protein as well as many novel genes that may belong to uncharacterized pathways involved in response to heat stress. For example, a lipid transfer protein and an alpha amylase inhibitor remained stable during heat shock in heat-tolerant cultivar Halberd. Reproductive stage heat tolerance QTL mapping results will also be presented.