Detection of stem rust resistance genes Sr42, Sr26 and SrTr6A in progeny of wheat cultivars Bahar and Pishtaz using marker assisted selection

Cereal rusts are the most important wheat diseases in Iran and worldwide. One of the most effective control measures of these diseases is deployment of resistant cultivars. The objective of this study was identification of stem rust resistance genes and pyramiding these genes in wheat cultivars Bahar and Pishtaz. For this purpose, initially the virulence of eighteen isolates of stem rust that had been collected from several parts of Iran was studied in cultivars/lines Bahar, Pishtaz, Eagle, AC Cadillac and Tr129. Results showed that cultivars AC Cadillac, Eagle, and Tr129 with Sr42, Sr26 and SrTr6A genes had good levels of resistance to all evaluated isolates. In order to transfer resistance genes to Bahar and Pishtaz cultivars, after initial and complementary crosses the F1 seedling resulted were evaluated for their resistance to stem rust and consequently the progeny of complementary crosses were screened for presence or absence of resistance genes using molecular markers. For Sr26 gene, primers Sr26#43 and BE518379; for Sr42 gene, primer STS (FSD-RSA); and for SrTr6A gene, primers GPW2295 and GPW4032 that showed polymorphism between parents were used to detect presence or absence of resistance genes. Using the seedling test in green house and also detection of molecular markers, it was found that for progeny of complementary crosses in cultivar Bahar transfer of resistance genes Sr26, Sr42 and SrTr6A have been successfully completed, and in Pishtaz based on distinctive ability of markers used, at least transfer of two genes of three genes in progenies was proved.