A highly significant genotype x environment interaction was observed in a varietal collection of Setaria italica under environments differentiated by sowing dates, locations, and seasons. The estimates of genetic variance as well as herita-bility and genetic advance, computed after eliminating the effect of environments, were invariably lower than the mean of individual estimates based on data of a single test. The genetic variation was influenced to a greater degree by interaction of genotypes with sowing dates and location than their interaction with season. The results clearly indicated the necessity of studying material under more than one environment for more precise estimation of various genetic parameters.
