Combining ability analysis for fiber quality and within boll yield components in Gossypium hirsutum L.

Cotton is an important cash crop of Pakistan grown for its natural fiber. Cotton plays a significant role in the economy of our country. Average seed cotton yield is still low in Pakistan as compared to other countries. The main reasons are high temperature, CLCuV attack, late wheat harvesting and dusky cotton bug attack. We can overcome these problems through hybrid production and selecting the superior genotypes. The present study was carried out in the experimental area of department of Plant Breeding and Genetics, University of Agriculture, Faisalabad to find out the best combiner genotypes to improve the quality traits and within boll yield components. For this purpose eight cotton genotypes were used and the experimental material was developed by crossing eight varieties MNH-886, CIM-598, FH-142, PB-899, MNH-147, MNH-129, KZ-191 and CIM-473 according to line x tester method including five lines and three testers in the glass house. The resulting 15 hybrid genotypes along with the parent genotypes were field planted during 2014 using randomized complete block design with three replications. Data was collected for the yield contributing components (plant height, number of sympodial branches, number of monopodial branches, number of bolls/plant), within-boll yield components (lint %, boll weight, seed volume, seed density, seed surface area, seed index, lint index, lint/seed, seed cotton yield, seed number/boll) and fiber quality characters (fiber length, fiber strength, fiber fineness, fiber uniformity). Collected data was analyzed to check the combining ability effects. The magnitude of additive variance was high for all the measured traits, indicated the predominance of additive genes in the inheritance of these traits. Seed cotton yield and number of sympodial branches shows both additive and non-additive genetic effects. FH-142 showed highest positive GCA for most of the traits. CIM-473 exhibited its potential as a good general combiner for seed cotton yield, lint percentage, sympodial branches, boll weight, seed volume, seed surface area. KZ-191 proved to be the best general combiner for monopodial branches, lint index and seed number/boll. MNH-129xFH-142 appeared the best combination among all the crosses followed by KZ-191xFH-142 for seed cotton yield, seed number/boll, seed density, seed surface area, seed index, fiber length and fiber strength.