Virulence Structure of Leaf Rust of Wheat in Peninsular India Hasabnis S.N., Joi M.B.*, Iihe B.M., Shinde V.K. Regional Wheat Rust Research Station, Mahabaleshwar 412 806, India. * Department of Plant Pathology, Agril. College, Kolhapur 412 111, India. Abstract Wheat samples infected by leaf rust (Puccinia recondita f. sp. tritid) were collected from wheat growing areas of Karnataka, Maharashtra and Madhya Pradesh states. The samples were analysed on new sets of differentials for monitoring the flora of the fungus. Remarkable shift in the population of the pathotype distribution was noticed. Pathotype 104-2 (21R55) was noticed as a most predominant one in the area in place of earlier predominant pathotype 77-5 (121R63-1). Flora had expressed change towards comparatively lower side of virulence. Pathotype 77-5(l21R63-1) had virulence on 13 Lr isogenic lines out of 16 included in the differentials, whereas 104-2 had virulence for 8 Lr genes. It means prevailing dominant population of the fungus had lost virulence on Lr 10, Lr, 13, Lr 15, Lr 20 and Lr 23. The Lr genes, Lr 9, Lr 19, and Lr 24 were not matched by any of the isolate whereas Lr 2c and Lr 14a were completely defeated by the enemy. Near isogenic lines Lr 10, Lr 20, Lr 15, Lr 13, Lr 23 and Lr 26 were proved to be the next best effective genes after intact genes Lr 9, Lr 19, and Lr 24. Top Key words Isogenic lines, Pathotype, Pucdnia recondita tritid, Virulence, Wheat. Top |