Plant breeders are more interested in genetic variance rather than phenotypic variance because it is the only portion of total phenotypic variance which is amenable to selection and brings about further improvement in the desirable characters. Therefore the current investigation was laid out in randomized complete block design with three replications during the season 2020 at the Cotton Research Institute, Tandojam. The mean square of genotypes differed significantly for the characters number of days to 1st boll formation, days to 1st boll opening, boll formed at 90 days after sowing, bolls plant− 1, boll weight (g), seed cotton yield plant− 1 (g) and GOT (%).while plant height, sympodial branches plant− 1 and staple length were non-significant. The result further related that among the parental lines, CRIS-508 takes maximum days to 1st boll formation, 1st boll opening and GOT (%).The CRIS-510 gave highest sympodial branches plant− 1, Bakhtawar showed taller plants and bolls plant− 1, Mehran exhibited maximum boll formation at 90 days after sowing, boll weight (g), seed cotton yield and staple length. Among the F2 progenies Mehran x Koonj, Mehran x CRIS-508 and Bakhtawar x CRIS-508 recorded better mean performance for most of the traits. The F2 population like Bakhtawar x CRIS-508 showed maximum (77.80%) for days to 1st boll opening, (82.03%) heritability bolls formed at 90 days after sowing (84.89%) for staple length. Mehran x Koonj expressed maximum (88.78%) heritability for sympodial branches plant− 1 and (90.52%) for GOT (%) could best be discovered in successive groups of selfing to expand these characters. Koonj x CRIS-510 gave high (82.83%) heritability for plant height, and (55.67%) bolls plant− 1 and Bakhtawar x CRIS-510 showed high heritability for seed cotton yield and could serve potential segregating populations in further selfing generations.

Background: Plant breeders are more interested in genetic variance rather than phenotypic variance because that is more amenable to selection and brings further improvement in the desirable characters. Therefore the current investigation was laid out to estimate heritability and genetic advance among F2 progenies of cotton based on these parameters of cotton, i.e. days to 1st boll formation, days to 1st boll opening, boll formed at 90 days after sowing, plant height, sympodial branches plant-1, bolls plant-1, boll weight (g), seed cotton yield plant-1 (g), GOT (%) and staple length.Result: The mean square of genotypes demonstrated substantial difference for most of the characters except plant height, sympodial branches plant-1 and staple length. Based on average performance variety Mehran recorded better performance for most of the components while in F2 progenies Mehran x Koonj and CRIS-508 x CRIS-510 were noted with superior result for various traits. In case of heritability estimation Bakhtawar x CRIS-508 showed maximum heritability (77.80%) for days to 1st boll opening, (82.03%) heritability bolls formed at 90 days after sowing (84.89%) for staple length. Mehran x Koonj expressed maximum (88.78%) heritability for sympodial branches plant-1 and (90.52%) for GOT (%). Koonj x CRIS-510 contributed high (82.83%) heritability for plant height, and Bakhtawar x CRIS-510 showed high heritability for seed cotton yield . considering genetic gain Mehran x CRIS-508 was noted with maximum genetic progression for plenty of the parameters. Conclusions: Mehran variety performed better for boll formation at 90 days after sowing, boll weight (g), seed cotton yield and staple length. Among the F2 progenies Mehran x Koonj, Mehran x CRIS-508 and Bakhtawar x CRIS-508 recorded better mean performance for most of the traits. Regarding heritability estimation F2 progenies Mehran x CRIS-508, Mehran x Koonj, Koonj x CRIS-510 and Bakhtawar x CRIS-510 showed high heritability and genetic gain for various traits that could be useful for further improvement.