Combining ability studies for yield components in wheat (Triticum aestivum)

This study was carried out in the research area of Department of Plant Breeding and Genetics, PMAS Arid Agriculture University Rawalpindi during 2007 - 2009. Combining ability studies were performed in a 5 × 5 complete diallel cross of five wheat genotypes for traits like plant height, number of tillers per square metre, spike length, spikelet number per spike, number of grains per spike, flag leaf area, peduncle length, 1000-grain weight and grain yield per plot. The portioning of the variance into its components exhibited that the general combining ability variance was greater than specific combining ability variance for number of tillers per square metre and number of grains per spike indicating the inheritance of additive type of gene action involved in these traits. For traits like plant height, spike length, spikelet’s number per spike, flag leaf area, peduncle length, 1000-grain weight and grain yield per plot, the specific combining ability variance was greater than the general combining ability variance, which indicated that these characters were conditioned by the non-additive genetic effects.