Genetic distance of maize inbreds for prediction of heterosis and combining ability

A panel of seven maize inbred lines belonging to Zemun Polje commercial pool were genotypized using SNPs bead chip. 21 hybrids, developed according to the half dialel mating design, were tested in the field together with inbred lines per se. The goal of the study was to determine the genetic distance among seven maize inbred lines and to establish whether there was a significant correlation between the genetic distance among parental inbreds and grain yield, specific combining abilities (SCA) and high-parent (HP) heterosis for the grain yield. The inbred lines ZPL2 and ZPL4 with the genetic distance of 0.487 were the most genetically distant parents, while inbred lines ZPL1 and ZPL2 with the genetic distance of 0.191 were the closest ones. Three subclusters of inbred lines were distinguished in the dendrogram. Inbred lines ZPL5, ZPL6, ZPL3 and ZPL7 were grouped into the first subcluster, while inbred lines ZPL1 and ZPL2, i.e. the inbred line ZPL4 were grouped in the second, i.e. the third subcluster, respectively. The values of the Spearman's rank correlation coefficient between the genetic distance among inbred lines based on the SNP markers, and grain yield, specific combining abilities (SCA) and high-parent (HP) heterosis were positive and statistically significant. The highest correlation coefficient was exhibited between the grain yield and high-parent (HP) heterosis (0.93), and then between the genetic distance and the grain yield (0.92) as well as between the genetic distance and high-parent (HP) heterosis (0.91).