Identification of genes for resistance to stem rust and their diversity in eight breadwheat varieties. I. crosses with susceptible parents and sr lines

A set of eight sources of stem rust resistance, viz., HD 2009, HD 2177, HD 2189, WH 169, HW142, TzPP, Marco Juarez Inta, and Pj 62-G6² X TzPP x Knott#2 (E 8643), were crossed to two susceptible parents and Sr lines. Tests in the seedling stage were carried out with races 40 and 295 of stem rust. The F₂ and F₃ investigations indicated the presence of 2–3 genes in different sources. These were dominant, recessive or complementary in nature. Modification of gene action from complementary to dominant duplicate factors in different genetic backgrounds was observed. The genes Sr6, Sr11 and Sr26 against race 40 were detected in some sources. There were indications of the presence of gene Srge against race 295. F₃ analysis indicated different genes for the two races, except Sr26 present in E 8643 causes resistance against both the races.