Estimation of Combining Ability in F2 Hybrids of Bread Wheat (Triticum aestivum L.) Genotypes

Abstract

The seed of 6 parental cultivars along with 15 F2 Hybrids of hexaploid wheat was planted in randomized complete block design with three replications 6 x 6 half diallel during 2016-2017 sat Southern Wheat Research Station, ARI, Tandojam, Sindh, Pakistan. Mean squares due to General Combining Ability (GCA) and Specific Combining Ability (SCA) variances were highly significant and significant for all morphological traits. It was noticed that additive, as well as nonadditive genes, were there for GCA and SCA. SCA variances were observed greater than those of GCA variances for five traits (PH, TPP, SL, SPS, GYPP) displaying the predominance of nonadditive genes, for some of the characters, nonetheless, GCA variances were more for the rest of the characters (GPS, TGW). Parental cultivars such as Khirman displayed maximum positive and desirable GCA effects for spike length and grains spike-1, Hamal for tillers plant-1 and spikelets spike-1 and Benazir and NIA-Sarang for grain yield plant-1 and seed index. On the other hand, Hamal and NIA-Sarang equally distributed negative, but desirable GCA effects for plant height. The SCA estimates revealed that Sindhu x Hamal manifested maximum positive estimates for spike length and grain yield plant-1, whereas Benazir x Sindhu was found as the best specific combiner for spikelets spike-1 and seed index, Benazir x Khirman and Benazir x NIA-Sarang for tillers plant-1 and grains spike-1. These F2 hybrids may be the best choice as a breeding material for hybrid crop development to improve yield characters. Therefore, it may be possible to take advantage of better general and specific combiners to further selection for the development of a hybrid variety of wheat which can assist to enhance the total production in Pakistan.