Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore - 641 003, India.
Generation mean analysis for six crosses in upland cotton (G. hirsutum L.) was done by using the six parameter model to assess the gene action underlying the inheritance of fibre characters viz., 2.5 per cent span length, uniformity ratio, bundle strength, maturity coefficient, fibre fineness and elongation per cent. It indicated the inadequacy of simple additive dominance model for all the fibre quality characters. All the three types additive, dominance and digenit non allelic interaction effects were responsible for genetic determination offibre properties. The non fixable gene effects (h), (j) and (l) were predominant over fixable effects (d) and (i) suggesting that complicated breeding procedures would be required for improving the traits.
