Combining abilities for the number of kernel rows per ear in silage maize

According to the analysis of variance, a genotype, year and a genotype x year interaction significantly affect variability of the trait number of kernel rows per ear. This number was the highest in the silage maize inbred lines ZPLB402, ZPLB403 and ZPLB405 in both years of investigation, resulting in low both positive and negative values of heterosis. The correct estimation of combining abilities is necessary in order to develop superior hybrids. This estimation was done on the basis of diallel hybrids after the method of Griffing (1956; method II, model I). The analysis of variance for combining abilities for the number of kernel rows per ear points to the significance of general and special combining abilities. The GCA to SCA ratio indicates that additive genes and the additive variance have a significant role in inheritance of this trait. Highly significant values of GCA for the number of kernel rows per ear for both years were found in the silage maize inbred lines ZPLB402 and ZPLB403, whereas inbreds ZPLB401, ZPLB404 and ZPLB406 had negative values. Highly significant positive, i.e. negative values of SCA for the number of kernel rows per ear for both years were found in the hybrid combinations ZPLB402 x ZPLB405 and ZPLB402 x ZPLB406, i.e. ZPLB402 x ZPLB406, respectively. Highly significant effects of SCA in hybrid combinations that include both parents with low GCA values are probably a result of the interaction among additive genes in parents. .