Genetics of Leaf and Stripe Rust Resistance in a Multiple Disease Resistant Stock of Bread Wheat

A genotype of wheat, ALDAN ‘S’/IAS 58 has shown consistent resistance to Karnal bunt, leaf and stripe rusts during past 17 years. In order to understand the nature and number of genes of practical significance against rusts, the screening for resistance at adult plant stage was performed using a mixture of prevalent races. Genetic analysis on the basis of segregation in RILs, BC₁F₂ and F₃ populations derived from a cross of ALDAN ‘S’/IAS 58 with WH 542 revealed two genes for leaf rust resistance whereas one gene governing stripe rust resistance was indicated in the donor stock on the basis of segregation in RIL population. A gene of minor effect was also indicated in WH 542 for stripe rust. F₁ plants were resistant to both these diseases indicating resistance to be dominant. The parental lines were screened at seedling stage also against different races, individually. ALDAN ‘S’/IAS 58 was found resistant to all the pathotypes whereas WH 542 was susceptible to 77-5 (of leaf rust) and 46S119 (of stripe rust).There is a good scope for combining resistance to leaf and stripe rusts and KB from this stock.