STUDY OF COMBINING ABILITY AND GENETIC PARAMETERS FOR YIELD AND ITS COMPONENTS IN WHEAT

Abstract

A set of seven wheat varieties from two different ecogeographical origins were studied in a diallel cross to find out the combining ability and the genetic parameters for yield and its components. The general and specific combining ability estimates for spike number per plant, spikelets per spike and seed size indicated predominance of additive gene effects, while for yield the variance for general and specific combining ability were of same order, suggesting importance of additive as well as non-additive effects. Per se performance of the varieties was in close agreement with the general combining ability estimate. The Vr-Wr and Wr-W' graphs showed overdominance for spikes per plant, spikelets per spike, 100-kernel weight and grain yield. In general the predictions regarding the parents made from general and specific combining abilities are in line with gene action indicated by the Vr-Wr and Wr-W' graphs for different characters. Implications of the genetic parameters on breeding approach in wheat have been discussed.