Estimation of Genetic Parameters of Some Yield and Fiber Quality Traits in CottonUsing Triple Test Cross Analysis

This study was done at Sakha Experimental Station; Agriculture Research Center, Kafr El-Sheikh governorate, Egypt, during three seasons (2022)(2023)(2024).Triple test cross manner was employed to disclose epistasis, additive, and dominance components of genetic variability for cotton yield, its components and fiber quality traits, three testers: Giza 86, Giza 93 and their F 1 hybrid (Giza 86 x Giza 93) were crossed as male parents to ten cotton lines as female parents: Giza 89, Giza 92, Giza 94, Giza 95, Giza 96, Pima S4, Pima S7, Karshenky, 10229 and Australy 13.In 2024 season a randomized complete blocks design with three replications was carried to evaluate 43 genotypes including three testers, ten inbred lines, 20 single crosses and 10 three-way crosses.Results revealed significant differences due to genotypes, parents, lines, hybrids and hybrids vs. parents for all studied trait, while Significant the testers and lines vs. testers were detected for most studied traits.The mean square for the deviations total epistasis (L1i + L2i -2L3i) revealed the presence of highly significant epistasis for all studied traits except micronaire reading.Showed that mean squares estimates due to additive additive (i) type were found to be non significant for all the traits studied.The presence of (j+l) epistatic types appeared to be highly significant in the inheritance of all the traits studied except micronaire reading.The epistatic type (i) interactions, was larger in magnitudes than the other epistatic type (j+l) for all traits studied except boll weight, lint index and micronaire reading.Additive Variances were greater than dominance variance for all studied traits.The degree of dominance (H/D) was less than unity suggesting the role of partial or incomplete dominance for all the studied traits.