Comparative variability studies for yield and fibre quality traits in F2 generations derived from single and double crosses in cotton (Gossypium hirsutum L)

Developing cotton cultivars with high yield and superior fibre quality is a major goal of any cotton breeding program. The present study emphasized on estimating and comparing genetic variability parameters in F2 generations derived from two double crosses and their four single crosses to isolate segregants with superior yield and fibre quality. Higher PCV and GCV (>20) with higher magnitude of variation were noticed for seed cotton yield per plant in single and double crosses but the magnitude of variability was found low in double crosses compared to single crosses indicating a higher degree of variability can be obtained in single crosses. Moderate to low PCV and GCV were found for GOT and LI. The moderate to high h2 (>60 %) with high GAM was noticed in double and single crosses for seed cotton yield per plant. For GOT and LI, moderate heritability (30-60 %) was noticed for single crosses while it was high for their double cross indicating that the population derived from the double cross has a higher ability to transmit the traits to its progenies. Except for micronaire values, the fibre quality traits recorded low to moderate levels of PCV, GCV, h2, and GAM in single and double crosses indicating that achieving the desired level of genetic improvement for them would be a painstaking effort in early segregating generations. However, selecting lines from these crosses for superior fibre quality will be rewarding in later advanced generations.