An analysis of genes for resistance against two Indian cultures of stem rust races of two bread wheats

Abstract

Two bread wheat accessions, E5008 and E6160, have been genetically analysed for resistance genes effective against Indian cultures of stem rust races, 15C and 122. The inheritance of resistance to each race has been determined from the F1 and F2 of the crosses (resistant parents with the susceptible variety, lsquoAgra Localrsquo) and F2 progenies from the backcross to lsquoAgra Localrsquo. Tests have been performed to see if the two varieties carry common genes/s for resistance. The identity of the genes for resistance has been established from relevant crosses with single gene lines carrying known genes for resistance. A single dominant gene effective to race 15C in E5008 has been demonstrated to be Sr9b. Of the two recessive genes, each producing distinct infection types (0; and 1-3) against race 122, one gene has been inferred to be Sr12 and the second to be a hitherto undesignated gene. The resistance of E6160 against race 15C is controlled by two genes, one dominant and one recessive. The dominant gene has been identified as Sr9b. The recessive gene has been inferred to be a new gene. Similarly, a dominant gene effective against race 122 in E6160 has been observed to be different from those so far designated. In addition, the presence of modifier gene/s in the variety, E6160 has been suggested.