Inheritance of Late Leafspot Resistance and Agronomic Traits in Peanut1

Abstract

Abstract Twenty peanut (Arachis hypogaea L.) populations in F2 generation from an M x N mating design involving five late leafspot (Cercosporidium personatum)-resistant female parents and four adapted male parents were evaluated for late leafspot resistance with a detached leaf culture technique. Agronomic traits were evaluated in the field. Objectives were 1) to identify the best parent for agronomic traits and the best source of resistance to late leafspot, 2) determine the correlations among components of resistance, 3) determine the correlations of resistance and agronomic traits, and 4) estimate heritability of late leafspot resistance. General combining ability was highly significant for agronomic traits and for most measurements of late leafspot resistance. Specific combining ability was significant for pod length and seed size. Of the male parents, NC 6 and NC 7 produced the best progenies for both agronomic traits and late leafspot resistance. Components of resistance to late leafspot among resistant female parents were not significantly different. NC 17090 produced the best progenies for pod yield and seed yield. NC 17135 produced progenies with good agronomic traits. Correlations among components of resistance to late leafspot indicated that lines with increased latent period, decreased lesion number, lesion size and defoliation, and reduced spore production can be selected. However, high yielding plants tended to be susceptible to late leafspot. Broadsense heritability for components of resistance was low to moderate (0.13–0.68). Narrow-sense heritability for parameters of resistance was consistently low (0.0–0.128). Selection for late leafspot resistance in the F2 populations was not effective.