Genetic distance in relation with specific combining abilities and heterosis for vegetative traits in maize

Abstract

Prediction of maize hybrids performances based on the genetic distance between their parents has long been an important path in the implementation of molecular marker technology in maize breeding programs. In this study genetic distance assessment of six maize inbred lines was done using 21 SSR primers. In the analysis, 92 alleles were detected with a mean of 4.38 per locus. Genetic distance (GD) determined using Simple matching coefficient (SM) between inbred lines ranged from 0.11 to 0.549. Using UPGMA clustering method a dendrogram was constructed in wich inbred lines were separated into two main cluster, one containing 2 inbred lines, and the other one with 4 inbreds. The bigger cluster furthermore was divided into two smaller subclusters. This classification was in accordance with known pedigree data of analysed genotypes. Six investigated inbred lines were furthermore crossed according to an incomplete diallel design forming 15 hybrid combinations. These genotypes were tested in field trials on 3 locations together with inbred lines per se. In this study maize vegetative traits: plant height and leaf number per plant were analyzed. Statistically significant specific combining abilities (SCA) and high parent heterosis (HPH) were calculated for both traits. Spearman’s rank correlation coefficient between genetic distance and SCA for plant height and leaf number was positive and statistically significant while the correlation between high parent heterosis and genetic distance although positive was not significant.