Genetic Parameters of Some Quantitative Traits in Cotton Using Triple Test Cross Analysis

: The current study was conducted at Sakha Agricultural Research Station Kafr El-Sheikh Governorate Egypt, during (2021-2023) growing seasons. Triple test cross analysis was employed to disclose epistasis, additive, and dominance components of genetic variability for yield components and fiber quality traits, using three testers as male with ten lines as female parents. Results demonstrated significant differences for each of genotypes, parents, lines, testers, hybrids, lines vs . testers and hybrids vs . parents for most studied traits. The mean square for the deviations total epitasis (L 1i + L 2i - 2L 3i ) revealed the presence of highly significant epistasis for all studied traits. Mean squares estimates due to additive × additive (i) type were found to be non significant for all studied traits. The presence of (i + j) epistatic types appeared to be highly significant in the inheritance of all the studied traits. The epistatic type (i) interaction, was detected to be much larger in magnitudes than the other epistatic type (i+ j) for all studied traits, except for seed index. Additive values were greater than dominance genetic variance for all studied traits except for boll weight and micronaire reading. The degree of dominance was less than unity suggesting the role of partial or incomplete dominance for all the studied traits, except for boll weight and micronaire reading which showed over dominance (greater than unity).