Inheritance of stem rust resistance derived from Aegilops triuncialis in wheat line Tr129

Ghazvini, H., Hiebert, C. W., Zegeye, T. and Fetch, T. 2012. Inheritance of stem rust resistance derived from Aegilops triuncialis in wheat line Tr129. Can. J. Plant Sci. 92: 1037-1041. Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is a devastating disease of wheat that can cause serious grain yield reduction. The emergence of Pgt race TTKSK (Ug99) and new variants in Africa is considered a threat to wheat production worldwide. Among the primary gene pool of wheat, only a few stem rust resistance (Sr) genes confer resistance to TTKSK. Wild relatives of common wheat are an important source of disease resistance. A preliminary study indicated that the common wheat line Tr129, which contains one or more Aegilops triuncialis translocations, is resistant to race TTKSK. The goal of this study was to elucidate the inheritance of resistance to Pgt in line Tr129 and investigate the novelty of the gene(s) conferring resistance. A population was generated by crossing RL6071 with Tr129 and F-2 and F-3 progeny were inoculated with Pgt race MCCF at the first leaf stage. Segregation of F-2 plants fit a 15:1 ratio (chi(2)(15:1) = 1.48, P = 0.22) indicating two dominant genes in Tr129 conditioned stem rust resistance to race MCCF. Segregation of F-3 families also fit a 7:8:1 ratio (chi(2)(7:8:1) = 3.28, P = 0.19) confirming the presence of two dominant genes. This is first report of stem rust resistance transferred to wheat from Ae. triuncialis.