Validation of molecular markers linked to the stem rust resistance genes effective in India

Abstract

An investigation was carried out to validate the already known molecular markers Xgwm533, Xcfa2019 and Xcfa2123, Sr24#12 and Sr24#50, Sr26#43 and BE518379, SCSS30.2 and Sr39-I and Sr39-II for stem rust resistance genes Sr2, Sr22, Sr24, Sr26, Sr31 and Sr39, respectively in wheat cultivars Kundan and UP 2338 carrying unknown stem rust resistance gene(s). The Sr2 and Sr22 gene specific SSR markers amplified the gene specific or expected allele in both Sr2 and Sr22 carrying and non-carrying cultivars. Sr24 associated STS markers (Sr24#12 and Sr24#50) amplified their respective expected fragments (500 bp and 200 bp) only in known Sr24 gene carrying cultivar, HD 2851. Two DNA markers (Sr26#43 and BE518379) known for Sr26 gene were screened. Marker, Sr26#43 amplified the specific fragment of 207 bp only in known source carrying Sr26 gene, while other marker, BE518379 functioned as null allele marker by not amplifying the critical band in Sr26 lines. SCAR marker, SCSS30.2 specific to Sr31 gene amplified the gene specific fragment in wheat cultivar UP 2338 confirming the presence of Sr31. Out of 14 entries tested for Sr39 gene including Kundan and UP 2338, the expected PCR product was not amplified in any of the entries indicating absence of Sr39 gene.