Relationship between phenotypic and genetic diversity of parental genotypes and the specific combining ability and heterosis effects in wheat (Triticum aestivum L.)

Abstract

The purpose of the study was to evaluate the relationship between the genetic distances (GD) and phenotypic distances (PD) of parents and the specific combining ability (SCA) and heterosis effects. The experiment comprised 18 parental genotypes of wheat (Triticum aestivum L.) and 76 F2 hybrids, obtained after crossing in a line × tester scheme. Parents and hybrids were examined in a field experiment conducted in a block design with three replications. SCA as well as mid-parent heterosis effects were estimated for selected morphological and technological traits. PDs and GDs were investigated between pairs of parental genotypes. GD between parental genotypes was evaluated by using randomly amplified polymorphic DNA markers. Heterosis was observed in all hybrids, and protein content exhibited the highest heterosis among the seven examined traits. The relationship between PD and GD as well as the SCA and mid-parent heterosis effects were evaluated using correlation coefficient. The correlation between PD, SCA and heterosis were low and not significant for the examined traits, whereas the correlation between SCA, heterosis and GDs were significant for protein content and rheological properties. The results indicate that GDs between parents can be used to predict performance of hybrids for selected technological traits.