Identification of High Throughput SNP Markers Linked to QTL for Drought Tolerance and Wsm2 Gene in US Hard Red Winter Wheat and Applications in Breeding

Integration of contemporary genetic techniques in wheat improvement to localize allelic variants linked to QTL is fundamental for improving yield under changing climate.Three studies were conducted using 217 recombinant inbred lines (RILs) derived from CO960293-2/TAM 111 and breeding populations derived from popular U.S. and Kenyan cultivars. In the first study, we primarily focused on mapping QTL associated with drought tolerance in the most planted hard red winter wheat cultivar in the US, TAM 111. RILs were phenotyped in three environments in 2013 and five environments in 2014. A set of 90,000 single nucleotide polymorphic (SNP) markers from Illumina’s Infinium iSelect array were used for genome-wide genotyping. QTL for grain yield were identified on chromosome 1A and 2B in both years and several QTL for yield components co-localized with QTL for grain yield. In the second study, Wsm2, a gene conferring resistance to wheat streak mosaic virus was fine mapped and the closely linked SNP markers were validated. In the third study, three popular Kenyan cultivars, Robin, Sunbird, and Eagle-10, were backcrossed with TAM 111 and BC1F2 seeds will be screened using high throughput linked SNP markers identified in study I for drought tolerance. The F2 and BC1F2 plants will be evaluated and selected in Kenya for rust and drought tolerance. The ultimate goal is to develop hard red spring wheat for Kenya and other African countries and winter wheat with combined rust resistance and drought tolerance for Texas and other similar US winter wheat regions.