Studies on Utilization of Second Generation Cotton Hybrids between the Recessive Glandless Varieties and the Dominant Glandless Lines

Twenty crosses were made between four recessive glandless varieties as female and five dominant glandless strains as male in upland cotton with NCII mating design to analyze the heterosis of yield and fiber qualities .Genetic analysis of all the above mentioned traits and predictation of their genetic effect value ,genotype value and heterosis were conducted by applying Zhu's (1997) genetic model. Data of yield and fiber character from nine parents ,twenty F 1's and F 2's were analyzed by additive dominance epistatic genetic model with MINQUE(1) approach. The results indicated that lint% was mainly controlled by additive effects, the other yield and yield components greatly controlled by the dominance effects with little epistatic effects for seed cotton yield and boll size. The fiber length and uniformity were mainly controlled by the dominance effects with little epistatic effects for fiber length. The additive effects were important for fiber strength, elongation and micronaire value. F 1 heterosis over better parent based on population mean averaged 27.9%,18.7%, 16.2%, 9.7% and 1% for lint yield ,the percentage of the first harvest, bolls per plant, boll size and lint percent, respectively, Their F 2 heterosis were 10.8%,5.1%,4.5%,4.6% and 1.2%, respectively ,with the same trend as that of F 1. F 1 heterosis over mid parent value based on population mean averaged 2.5%, 0.2%, 1.8%,0.8%, 2.7% for fiber length, micronaire, strength, elongation, and uniformity ,respectively, F 2 had shorter fiber ,better uniformity and no reduction for fiber strength, elongation and micronaire, as compared with that of F 1. It was suggested that the dominant glandless gene may play an important role in cotton hybrid vigour.