Gene effects of partial resistance to leaf rust (Puccinia triticina Erikss. and Henn.) in bread wheat (Triticum aestivum L. em Thell)

Abstract

Genetic basis of partial resistance to leaf rust in wheat involving cross combination of slow rusting × susceptible parents was investigated using generation mean analysis. In order to examine the effect of minor genes, major genes (Lr1, Lr10, Lr13, Lr23 and Lr26) for resistance present in the slow rusting parents were nullified by inoculating with virulent leaf rust races.The partial leaf rust resistance was studied using area under disease progress curve (AUDPC) and final disease severity (FDS). Scaling and joint scaling tests for all the crosses indicated the importance of additive (d), dominance (h) as well as epistatic (i, j and l) gene effects in the inheritance of partial leaf rust resistance based on AUDPC and FDS. Three out of four crosses exhibited duplicate type of epistasis, whereas, additive (d) and additive × additive (i ) interactions were significant in most of the crosses offering good scope of selection in early segregating generation for durable leaf rust resistance.