The present study aimed at assessing the mid (MPH) and better (BPH) parents heterosis, potence ratio (PR) and genetic parameters for yield, its components and fiber traits in eighteen F₁ hybrids developed by crossing between six lines and three testers using line × tester mating design.Pearson correlation coefficient and principal component analysis (PCA) were used for a better understanding of the relationship during this study. The lines, testers and their F₁ hybrids were evaluated in a randomized complete block design (RCBD) with three replications at Sakha Agriculture Research Station, Kafr El- Sheikh Governorate, Egypt, during the 2020 cropping season. The variances due to the sources of variation in line x tester analysis exhibited significant differences for most measured traits.The proportional contribution of line × tester was higher than the individual contribution of lines and testers for most studied traits. The lines G.90x Aus.12 and Uzbekistan as well as the tester G.97 showed superior cotton yield and most studied traits based on mean performance compared to the other parents. The hybrid combinations TNB x G. 94, (G.90x Aus.12) x G.86 and G.96 x G.94 were identified as excellent based on mean performance, MPH, BPH and PCA analysis for cotton yield and most studied traits. Potence ratio exhibited that the hybrid combinations have positive or negative nature for studied traits.Genetic parameters indicated that non-additive gene action effects had a more important role compared to the additive in controlling all the studied traits, except the number of seeds/boll trait. Significant correlation coefficients were found between all possible pairs of mean performances, MPH, BPH (positive) and PR (negative) parameters for most investigated traits. PCA can be used as a suitable method for studying the studied traits and to determine the best hybrids across line x tester analysis. Finally, and based on the results of statistical methods used in this study, the parents and hybrids above are promising enhancement and improvement of cotton productivity and its fiber quality through use in cotton breeding programs in Egypt.