Abstract

Increase in seed cotton yield on a sustainable basis is a primary objective of cotton breeding programs, which is a result of an effective exploitation of quantitative (polygenic) traits. The diallel cross techniques is mainly applied for studying the nature of action and genetic constitution of cotton genotypes. Six cotton varieties were crossed in a complete diallel fashion to study the inheritance of seed cotton yield and its components, lint percentage and fiber length. Field evaluation of six parental genotypes and thirty F₁ was made in a randomized block design with three replications. Genotypes mean values differed significantly (P≤0.05) for all traits and greater than the dominance component (H₁ and H₂). The dominance effect H₁ and H₂ was non significant for number of bolls per plant and fiber length. The value of H₂/4H₁ indicated a symmetrical and unequal distribution of dominant genes in the parents for all traits except for lint percentage as the H₂/4H₁ value 0.24 is very close to 0.25, which indicated symmetrical and equal distribution of dominant genes in the parents for lint percentage. Estimates of narrow sense heritability (h²_n.s) were higher for all the traits that are due to additive gene action. The results of the present study indicated that the pedigree of progeny selection will be helpful to improve these traits.

Key words: Cotton genotypes, diallel cross, Gossypium hirsutum L, heritability, seed cotton, genetic studies, yield components.