Study of combining ability effects and the contribution of gene action for various plant parameters in Gossypium hirsutum L

In present research 5×5 complete diallel analysis was performed on five genotypes named via FH-114, FH-207, CRS-456, MNH-992 and Kahkashan for the study of combining ability effects and the contribution of gene action for various plant parameter regarding height of plant, direct and indirect fruit bearing branches, first fruiting branch, yield and its related traits and the collected data for such traits were analyzed by statistical analysis. F. calculated value for the F1s from statistical analysis indicates the maximum variation for all parameter. Results observed from the complete diallel mating design indicate that the collected data for all parameter were enough for Griffing’s approach (1956). Combining ability analysis for all the parameter presented the maximum differences for GCA and SCA effects. Less contribution of the GCA variance determine that the traits such as height of plant, indirect fruit bearing branches, weight of individual boll, seed cotton yield of individual plant, lint index seed index, percentage of lint, number of boll on a single plant and first fruiting branch is governed by non-additive type of gene action because the value of GCA/SCA ratio is less than one which indicates that hybrids are more vigorous for all parameter under study but the greater contribution of GCA variance indicates that the traits such as direct fruit bearing branches are largely controlled by dominant gene action because the value of GCA/SCA is greater than one.