ESTIMATION OF COMBINING ABILITY, HETEROSIS, AND HERITABILITY FOR SOME YIELD, YIELD COMPONENTS AND FIBER QUALITY TRAITS IN COTTONS (Gossypium barbadense L.)

: The present studied carried out at Sakha Agricultural Research Station, Cotton Research Institute, Agricultural Research Center, Egypt, during 2022 and 2023 growing summer, during 2022 growing season, six cotton varieties of cotton belong to (Gossypium barbadense L.) were sowing and crossed in a half diallel mating design produce 15 F1 hybrids. The F1 hybrids and parents growing in 2023 season at randomized complete blocks design with three replications. The results showed that the squares of the genotypes, parents as well as crosses were highly significant for all traits studied with boll weight trait parents. The parental genotypes Giza 88 and Giza 92 gave significant (desirable) GCA effects for most fiber properties. Karshenky and Australy 13 showed GCA positive significant effects of most yield traits, this direction is desirable. Both of Giza 88 x Giza 86 and Australy 13 x Karshenky crosses recorded significant (desirable) SCA effects for most yield and fiber properties. Desirable relative to mid- and better-parent for some yield traits were found for the crosses, Giza 88 x Giza 86 and Australy 13 x Karshenky while, the crosses Giza 92 x Pima S7 and Giza 92 x Karshenky indicated desirable for some studied fiber properties. Non-additive genetic variances were larger than the additive genetic variance with respect to all traits studied. The broad sense heritability of seed cotton yield per plant was the highest value (93.91%) while the lowest value was recorded to boll weight (50.51%). Generally, Karshenky and Australy 13 could be used in breeding programs for improving high yielding varieties, while Giza 88 and Giza 92 could be considered as excellent parents for breeding programs to produce new varieties characterized with best fiber properties.