Genetics of stem rust resistance in common wheat genotypes WR95 and Selection T3336

Abstract

Genetic stocks WR95 and Sel.T3336 were screened against most prevalent races of stem rust viz., 40A, 40-1 and 117- 6 at seedling stage under controlled conditions. Both the genetic stocks, WR95 and Sel.T3336 were found resistant to all the three races. Genetic analysis revealed that WR95 carries a single recessive gene for rust resistance. An effort was made to locate the gene using monosomic series, however, the gene proved to be hemizygous ineffective in monosomic F1s. WR95 was also screened with validated molecular markers of the stem rust resistance genes Sr24, Sr25, Sr26, Sr31, Sr36, and Sr38. None of these genes could be detected in WR95 showing that the resistance gene present in WR95 is diverse from these genes. Sel T3336 showed segregation for one stem rust resistance gene against race 40-1. However, screening with molecular markers showed the presence of stem rust resistance genes Sr24 and Sr26 in Sel.T3336. The resistance identified in WR95 may prove very useful in breeding.