2012 Annual Report 1a.Objectives (from AD-416): The objective of this project is to couple molecular genetics and physiology such that we can identify drought tolerant parental genotypes and those genotypes that have an increased likelihood of having unique drought tolerant alleles. 1b.Approach (from AD-416): The approach of this research is to. 1)examine the extreme phenotypes in greater physiological detail under control and managed drought conditions,. 2)compare the responses of the extreme genotypes to other measures of drought tolerance,. 3)develop populations segregating for CID and NDFA (including developing RIL) based on genotypic and physiological criteria,. 4)phenotype segregating populations,. 5)initiate a mapping program to identify genes associated with CID and NDFA, and. 6)integrating global transcriptome analyses with physiological characterization and molecular marker development. 3.Progress Report: Extreme phenotypes (60 genotypes) were grown in 7 environments in the 2011 season. The following data were collected: ureide concentrations, carbon isotope discrimination, and nitrogen isotope discrimination. In addition, yield was determined at selected sites. Carbon isotope and ureide data were analyzed data together with molecular marker data. Two manuscripts for publication in peer-reviewed journals are in preparation. Seeds of extreme phenotypes have been planted for the 2012 season. Experiments for transcriptome analyses are under way for PI442012A and PI404199 and leaf tissue collected for RNA analysis. Crosses for carbon isotope, nitrogen isotope, and ureide concentration were conducted and F2 seeds from 11 populations will be planted in 2012. Data from physiological experiments from the two previous seasons is being analyzed and the evaluation of extreme phenotypes (parents of populations) under field and controlled conditions is continuing. Recombinant inbred line populations based on strategies devised based on the results obtained from the 2012 field season are being developed.