Heterosis and Estimation of General and Specific Combining Ability as Base for Selected Superior Recombination of the Some Crossed Cotton Genotypes

The objective of this study was to determine the general and specific combining abilities and heterosis of some cotton genotypes for yield, its components and fiber traits using line x tester mating design. Nine parents (six line and three testers) were crossed in a line x tester mating design in 2020 season. Nine parents along with their eighteen F1 crosses were studied in a randomized complete block design (RCBD) with three replications during 2021 at Sakha. Agricultural. Research. Station. Kafr El-Sheikh, Governorate, Egypt. Based on line x tester analysis, the variance due to genotypes, parents, crosses and parent vs. cross exhibited significant differences (P. 0.01) for most yield, yield components and fiber traits. The variance due to GCA of lines x testers and SCA of line x tester interactions were highly significant for most studied traits, indicating the importance of both additive and non-additive gene actions in controlling these traits. The estimates of GCA and SCA effects revealed that the parent and some crosses were having desirable and significantly GCA and SCA effects, respectively. High mean performances and significantly GCA effects values were observed of line Giza 92, Giza 75 and tester Giza 97 for most studied traits, hence, these parents can be used as for generation superior cotton hybrids. The best values of mean performances, SCA effects and heterosis were found in the combinations Giza 94 x Giza 92, Giza 97 x Suvin for most yield and yield components and the cross Giza 97 x (Giza 75 x Sea) for yield and fiber traits. These crosses are considered as the promising crosses to be used in breeding programs for produce hybrid cotton and improvement for these traits in Egypt.