EFFECT OF SELECTION ON THE COMPONENTS OF GENETIC VARIABILITY FOR GRAIN YIELD AND ITS COMPONENTS UNDER TWO PLANT DENSITIES IN MAIZE (ZEA MAYS L.)

Abstract

Using the NCI design crossing system, full-sib and half-sib families were developed in th~ original and selected populations of the maize composite Vijay. The progenies from each population were grown under low and high plant densities (53,200 and 88,850 plants/ha, respectively) and the genetic parameters for grain yield and its components estimated separately as well as pooled under two densities. The selected population of Vijay registered 16.3% gain in the grain yield over the original one in the pooled analysis. Nonsignificant differences between the estimates of oi in original and selected populations for grain yield indicated that selection had not brought about any change in additive genetic variability for this trait. In general, the estimates of cri were relatively lower under high plant density for majority of characters, thus showing that genetic advance selection would be lower under high plant density than under low density. The expected genetic gain in the selected population, but as there was no significant change in the components of genetic variance, therefore, continued response to selection can be expected. Selection under normal plant population is expected to be more efficient as high plant density led reduction of additive variance.