The analysis of combining abilities of maize inbred lines of different cycles of recurrent selection for the ear length

Abstract

The evaluation of combining abilities is an inevitable step in the development of highly productive maize hybrids. The mean values, heterosis, and general (GCA) and specific (SCA) combining abilities of maize inbreds and their hybrids were observed in this study. Inbreds of different cycles of recurrent selection of two maize synthetic populations BSSS and BSCB1 were selected for the study. Hybrids showed higher values of the ear length than inbreds, since inbreeding depression occurs in inbreds as a result of the inbreeding process. The analysis of variance of combining abilities indicates significant positive values of GCA and SCA over both locations and both years of investigation. Since GCA to SCA ratio for inbreds of the BSSS population and parents of an elite hybrid was lower than unit, it can be concluded that a non-additive gene effect might be more important in controlling the expression of this trait. On the other hand, the additive gene effect was the most important for inbreds and hybrids originating from the BSCB1 population. The highest GCA values were recorded in inbreds ZPL1 and ZPL2. Hybrids derived from these two inbreds showed high SCA values in both years of investigation.