Genetic Variability in Two heterozygous maize populations* Prodhan H. S., Dana S., Sarkar K. R.** Department of Genetics and Plant Breeding, Bidhan Chandra Krishi Viswa Vidyalaya, Kalyani-741 235, India **Division of Genetics, I.A.R.I., New Delhi-110 012. *Part of the Ph.D. thesis submitted to B.G.K.V. V. by the first author. Abstract Estimates of additive genetic and dominance variance for days to silk, plant height and ear height were obtained from half-sib family groups developed in the two composite populations of maize, population 61 and 62. Half-sib progenies were developed using Design I mating system and tested in two separate trials for two populations at two diverse locations—Kalyani and Kalimpong. Estimates could not be computed over locations due to heterogeneous error variances at two locations. Estimate of additive genetic variance was considerably larger than that of dominance variance for days to silk and plant height in both the populations at two locations. In contrast, estimate of dominance variance for ear height was larger in Population 62 at both the locations while contrary results were obtained in Population 61 for the same character. It is assumed that there might have been some chance of assortative mating which would cause a downward bias in the estimate of dominance variance. Additive genetic variance played a major role in the expression of days to silk and plant height in both the populations and for ear height in Population 61 whereas dominance variance played a major role for expression of ear height in Population 62. There is considerable scope for obtaining further early maturity and lower ear placement in both the populations and short statured plants in Population 62 through selection. Considerable genetic gains for these characters in the two populations from one cycle of full-sib family selection were predicted. Mass selection was estimated to be less effective than full-sib family selection. It is suggested that considerable improvement can be achieved in early maturity, and ear height in these two populations and in plant height in Population 62 through several cycles of full-sib family selection. Top |