Genetics of stem rust resistance in four popular durum wheat cultivars

A study was conducted to understand the mode of inheritance and extent of diversity of stem rust resistance in four popular durum wheat cultivars of central India viz., HI 8498 (Malav Shakti), HI 8663 (Poshan), HI 8713 (Pusa Mangal) and HI 8737 (Pusa Anmol) using Puccinia graminis tritici (Pgt) pathotypes 15-1 (123G15) and 40-3 (127G29). These cultivars were crossed with susceptible parents i.e., Motia and Malvi Local and were also crossed among themselves in half diallel fashion. The F2 and F3 segregation data revealed that a single dominant gene each controlled resistance to the pathotype 40-3 in HI 8713 and HI 8663, while two dominant genes each governed resistance to this pathotype in HI 8737 and HI 8498. A single dominant gene each conditioned resistance to the pathotype 15-1 in all the four cultivars. The F2 segregation data of the intercrosses among the resistant parents showed that three different resistance genes controlled resistance among four cultivars against each Pgt pathotype 40-3 and 15-1. These genes seem to be different from the most commonly postulated stem rust resistance genes in Indian durum wheat germplasm viz., Sr11, Sr12, Sr7b and Sr9e which are ineffective/less effective against the test pathotypes. Hence, the genes identified in the present study can be utilized in broadening the genetic base of stem rust resistance in Indian durum wheat.