The Triticeae Coordinated Agricultural Project: Connecting Genotypes to Phenotypes

The Triticeae Coordinated Agricultural Project (TCAP) seeks to identify quantitative trait loci associated with climate change traits (nitrogen and water use efficiency, and fungal disease resistance) and use that information in molecular breeding to improve wheat and barley.  Multiple populations and association mapping panels form the basis of the mapping efforts.  Two key barley resources are the National Small Grain Collection (NSGC) barley core and the wild barley introgression line population.   The NSGC core consists of 1860 unique accessions (mainly landraces and historical cultivars/breeding lines) from 94 countries.  The NSGC Core was genotyped with 7,824 SNPs and phenotyped for numerous agronomic (heading date, height, thousand kernel weight, and nitrogen and water use efficiency), morphological (lemma and aleurone color) and disease resistance (stripe rust, leaf scald, net blotch and Russian wheat aphid) traits.  The wild barley introgression line population was developed by crossing an elite six-row spring barley cultivar Rasmusson with 25 wild barley accessions to develop 796 BC₂ lines. 4,229 SNPs were mapped on the population through genotyping the population and imputing SNP alleles from the parents.  For both the NSGC Core and the wild barley introgression population, the combined genotype and phenotype data were used in genome-wide association studies that identified numerous QTL.  These results will be discussed in relationship to the utility of these approaches to mapping and to previous QTL mapping results.