Diallel analysis of yield components,fibre quality and bacterial blight resistance using spaced plants of cotton

Summary Hayman analysis for lint percentage, boll weight, fibre quality and bacterial blight resistance of a ten-parent half-diallel set of crosses was conducted in Upland cotton. The ten parents represented a fixed sample of the best germplasm available to Australian breeders for the characters of commercial importance. Heterosis and inbreeding depression were detected particulady for boll weight and blight resistance. An analysis of genetic components and parameters indicated that since additive effects were substantial and heritability high, early-generation selection of spaced plants and pure-line breeding should be successful. Some genotypes were identified as being potentially good donors for hybridization since they possessed dominant genes for improved character expression. Acala C-1 was identified as the first-choice parent for increased boll size. Coker 315 for increased span length, while Namcala was the best parent for breeding improved fibre strength. McNair 220 possessed the most dominant genes for high lint percentage. Reba P279 and Siokra were the only parents with resistance to the prevelant race of bacterial blight.