Quantitative‐genetic parameters of sorghum growth under striga infestation in Mali and Kenya

Abstract

Abstract To estimate quantitative‐genetic parameters of sorghum for resistance to the hemi‐parasitic weed striga [ Striga hermonthica (Del.) Benth.] and for agronomic traits, 36 diallel F 2 populations and their nine parental lines were evaluated under severe striga infestation at two locations each in Mali and Kenya. Location means for grain yield ranged from 132 to 254 g/m 2 . F 2 populations outyielded lines on average by 18%. For striga emergence traits, F 2 heterosis values ranged from ‐36% to 232% among populations. Genetic and genotype x environment interaction variances of lines and F 2 s were highly significant for all traits. Broad‐sense heritabilities for areas under striga severity progress curves and grain yield were 0.83 and 0.90 in lines, and 0.81 and 0.89 in F 2 s, respectively. General and specific combining ability, and their interaction effects with locations were significant for most traits. F 2 superiority for grain yield under striga infestation demonstrates the potential merit of heterozygous cultivars in the target areas. Significant genotype x environment interaction entails multilocational testing to identify stable resistance. A combination of resistance with striga tolerance is recommended to breeders.