Diversity for Resistance to Stem and Leaf Rusts in Indian Wheat Germplasm

In India, three wheat species -Triticum aestivum L. emend. Fiori & Paol (bread wheat), T. durum Desf. (durum wheat) and T. dicoccum Schrank (khapli wheat) are under cultivation, which are attacked by stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & Henn.) and leaf rust (P. triticina Eriks). Out of 120 genotypes each of durum and bread wheats tested including released varieties, advanced generation lines, genetic stocks and landraces, 67 bread wheat and 71 durum genotypes showed resistance to stem rust; and 45 bread wheat and 50 durum genetic stocks showed resistance to leaf rust, based on field scores of five successive crop seasons (2004–2009) under rust epiphytotic conditions. On the basis of patterns of their seedling responses to 24 pathotypes of stem rust and 40 of leaf rust, at least 17 diverse groups among bread wheats and 18 among durums could be recognised for resistance to stem rust, while 12 groups among bread wheats and nine among durums could be identified for leaf rust resistance, indicating wider resistance base of Indian wheat germplasm. In all, 31 bread wheat and 36 durum genotypes showed resistance to both the rusts, which can serve as donors in wheat crop improvement.