08. Evaluation of inheritance pattern for leaf rust resistance genes and heritability estimates for agronomic traits in F2 progenies of bread wheat genotypes
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Abstract
The current experiment was conducted at experimental farm of Nuclear Institute of Agriculture, Tandojam, during the growing season of 2013-14, which comprised of seven wheat genotypes including four leaf rust resistant (Sunco, Vasco, SD-222 and SD-333) and three susceptible (TD-l, ICARDA and SD-888). These wheat genotypes were used to develop four F2 cross combinations (TD-1 × Vasco, ICARDA × SD-222, TD-1 × Sunco and SD-888 × SD-333) for the estimation of heritability and genetic pattern of resistance genes. The observations were recorded on gain yield associated traits to evaluate genetic potential of the F2 populations. The analysis of variance revealed significant differences (P≤0.05) among the genotypes for all the studied traits which suggested that the breeding material is worth for selection of desirable plants from subsequent segregating generations. With regards to heritability percentage in broad sense, the F2 progeny TD-1 × Sunco expressed high heritability for days to 75% heading (h2=60.80%, GA=1.82), days to 75% maturity (h2=71.50%, GA= 2.40) and tillers plant-1 (h2=32.72%, GA= 12.44). Similarly, the F2 progeny TD-1 × Vasco showed high heritability (h2=88.89%, GA= 8.07) for plant height; SD-888 × SD-333 revealed high heritability (h2=92.33%, GA= 29.83) for biological yield plant-1; ICARDA × SD-222 expressed high heritability (h2=44.61%, GA= 12.77) for harvest index. The present findings suggest that most of the yield associated traits have been successfully transmitted. The information generated will be helpful for better understanding and selection of desirable material especially in early generations. Furthermore, phenotypic data expressed 3:1 ratio in F2 populations of four crosses which indicated that both (Lr24 and Lr32) are single dominant genes, thus specifying the usefulness of these genes for the breeders to incorporate in mega wheat varieties susceptible to leaf rust and to save guard the future harvest.
Keywords: Inheritance pattern; heritability; F2 population; Bread wheat