Mapping and validation of the genes for resistance to Pyrenophora teres f. teres in barley (Hordeum vulgare L.)

Identification and deployment of disease resistance genes are key objectives of Australian barley breeding programs. Two doubled haploid (DH) populations derived from Tallon x Kaputar (TK) and VB9524 x ND11231 (VN) crosses were used to identify markers for net type net blotch (NTNB) (Pyrenophora teres f. teres). The maps included 263 and 250 markers for TK and VN populations, respectively. The TK population was screened with 5 pathotypes and the VN population with 1 pathotype of NTNB as seedlings in the glasshouse. In addition, the TK population was subjected to natural infection in the field at Hermitage Research Station, Qld. Analyses of the markers were performed using the software packages MapManager and Qgene. One region on chromosome 6H was strongly associated with resistance to NTNB in both populations (R-2 = 83% for TK and 66% for VN). In the TK population, 2 more quantitative trait loci (QTLs) were identified on chromosomes 2H and 3H, with R-2 values of 30% and 31%, respectively. These associations were consistent over all pathotypes studied during the seedling stage. The same QTL on chromosome 6H was also found to be highly significantly associated (R-2 = 65%) with the adult plant ( field) response in the TK population. There are several very closely linked markers showing strong associations in these regions. Association of the 4 markers on chromosome 6H QTL with resistance to the NTNB has been validated in 2 other DH populations derived from barley crosses Pompadour x Stirling and WPG8412 x Stirling. These markers present an opportunity for marker assisted selection of lines resistant to NTNB in barley breeding programs.