Combining ability for fiber quality parameters and within-boll yield components in intraspecific and interspecific cotton populations

The major problem with the simultaneous improvement of yield with higher fiber quality is the negative association due to the linkage and pleiotropic effects between lint yield components and fiber quality parameters. The objectives of this research were to estimate the general combining ability (GCA) of parents and specific combining abilities (SCA) of hybrids for fiber quality parameters and within-boll yield components, and to determine the association of fiber quality parameters with basic within-boll lint yield components. In this study, eight cotton cultivars and 15 F-1 hybrids obtained by crossing five lines and three testers in the line x tester mating system during 2006 were planted in a randomized block design with four replications in 2007. The predominance of non-additive gene action was estimated for all traits except for the upper half mean fiber length (UHM), fiber strength, and seeds per boll, which were controlled by an additive type gene action due to the high GCA variance. Among the parents, 'Askabat-100' and 'Carmen' were the best general combiners for fiber length, strength, and uniformity index (UI). Additionally, 'GW Teks' and 'Sahin-2000' were determined to be good combiners for lint weight per seed (L/S) and spinnable fibers per seed (F/S). The SCA effects showed that the best specific combination was 'Sealand-542' x 'Sahin-2000' and 'TAM 94L-25' x 'SG-125' for lint percentage, L/S, and lint weight unit per seed surface area. The most important fiber quality parameters, UHM, fiber strength, and UI, were negatively associated with the most basic within-boll lint yield components, US, and F/S.