Genetic resources for disease resistance in wild diploid Triticum and Aegilops species

One hundred and twenty accessions of wild diploid species of Triticum and Aegilops were screened for resistance to stem rust (Puccinia graminis triticl), leaf rust (Puccinia recondita), stripe rust (P. striiformis) and powdery mildew (Erysiphe graminis tritici) under natural and artificial epiphytotic conditions in adult plant stage at Wellington and New Delhi. Twelve accessions belonging to T. monococcum and Ae. squarrosa were tested for resistance to karnal bunt (Neovossia indica). Einkon wheats, T. boeoticum, T. monococcum and T. sinskajae exhibited spectacular resistance to leaf rust and powdery mildew. Many accessions of Ae. speltoides showed resistance to stem rust also. Resistance to all the rusts and powdery mildew was observed among species such as Ae. comosa, Ae. markgrafii, Ae. uniaristata, Ae. mutica and Ae. umbellufata. Twelve diverse wheat stocks carrying specific genes derived from diploid wild species were also evaluated for rusts. The study revealed that the genes, Lr9, Lr28, Lr32 and Lr36 conferred a high level of resistance to leaf rust while Sr32 conditioned adult plant resistance to stem rust.