SELECTION RESPONSES FOR GRAIN WEIGHT IN SOME MASS SELECTED AND INTERMATED POPULATIONS OF WHEAT (TRITICUM AESTIVUM L.)

Abstract

Mechanical mass selection for grain size, followed by two cycles of intermating among the high grain-weight populations, was done to achieve improvement in grain yield. Forty progenies each from five mass selected, eight populations of the first and four of the second intermating cycles were evaluated for plant height, number of grains/spike, l000-grain weight, and grain yield. Mechanical mass selection and each cycle of intermating were effective to increase l000-grain weight, indicating the accumulation of favourable alleles in the segregates. There was slight improvement in number of grains/spike also in the progenies of the first intermated populations which pushed up grain yield. However, the second cycle of intermating was not effective in increasing grain yield due to reduction in number of grains/spike. Correlation studies also revealed the usefulness of one cycle of intermating for improving grain yield. Therefore, it is proposed to practice only one cycle of intermating to achieve optimum expression of yield components.