Genetic studies of fiber quality parameter and earliness related traits in upland cotton (Gossypium hirsutum L.)

Combining ability analysis was carried out for fiber quality and earliness related traits in a 5×5 diallel cross using Griffing, Method-I, Model-II. Analysis of variance components indicated that except days to first boll opening and boll maturation period all character were predominantly controlled by nonadditive type of gene action. Genotype NIAB Krishma was the best general combiner for days to flowering and fiber strength and S-12 for boll maturation period, seed cotton yield and fiber length. Hybrids NIAB Krishma × MS-39, CP-15/2 × S-12, S-12 × MS-39 and S-12 × NIAB Krishma showed the best SCA (Specific Combining Ability) and reciprocal effects for all characters. Regarding simple correlation analysis days to flowering showed significantly positive correlation with days to first boll opening, whilst fiber length showed negative correlation with days to first boll opening. Furthermore, fiber strength association with fiber fineness was significantly negative but with fiber length the association was positive. The boll maturation period was positively correlated with days to first boll opening while negatively correlated with days to flowering. SCA variance was greater than GCA (General Combining Ability) effects for days to flowering, fiber strength and fiber fineness indicates the importance of non-additive type of gene action thus heterosis breeding could be exploited for these traits. Additive genetic effects were predominant for days to flowering and boll maturation period thus pedigree method of selection could be exploited for these traits.