Study of a diallel cross for resistance to bacterial blight (Xanthomonas campestris pv. malvacearum (Smith) Dow.) in cotton (Gossypium hirsutum L.)

Abstract

A total of 8 parents (from Cameroon, Cote d'Ivoire, Togo and Chad) and their 56 F1 hybrids from a complete diallel cross were evaluated for resistance to X. campestris in trials in Chad. Significant differences were observed between the genotypes. F1 susceptibility was significantly higher than that of the parents, which is probably due to the existence of residual heterozygosity in certain parents. Heritability was low (ч24%), and it is suggested that the breeding strategy for resistance to X. campestris should make use of either numerous crosses to take advantage of the SCA effects or recurrent type selection.