Inheritance of strip rust resistance in wheat cultivars

摘要

In order to study inheritance of resistance to stripe rust (Puccinia striiformis) a half-diallel set of crosses was produced from five parents including four resistant and one susceptible. Parents and their Fl's were assessed for latent period with two races in greenhouse. Data were analyzed using GrifFing and Jinks-Hayman methods of diallel analysis. The results clearly indicated that nonadditive genetic variance predominantly controlled the inheritance of resistance to yellow rust disease. The parent M3 was the best general combiner for resistance under both races. The cross Bulani x M3 and M3 x M4 showed the best specific combining ability. All the crosses showing superior specific combining ability effects were resulted from poor x good generalcombiners for the disease resistance. The average degree of dominance over all loci indicated that there is over dominance of rust resistance. Heritability estimates in broad sense was high whereas in narrow sense was low. Predominance of non-additive genetic variance coupled with low heritability suggested that simple selection procedures such as pedigree breeding would not be useful for improving the level of resistance.