Molecular characterization of tropical sweet corn inbred lines using microsatellite markers

Abstract

Genetic variability among 13 tropical sweet corn inbred lines derived from source populations originating from five tropical countries was investigated using 95 polymorphic microsatellite markers. It was found that 92.9% of total molecular variance was due to variations among the inbred lines. This was further supported by the presence of high values of DST, FST, GST and FIT, indicating high genetic variation among the inbred lines. The average number of alleles and effective number of alleles were both close to one allele per locus per inbred line. Departure from Hardy-Weinberg equilibrium was observed with a drastic reduction of the observed heterozygosity, resulting in a lower index of genotypic diversity than expected for each of the inbred lines. The inbred lines were further assigned into six main heterotic groups based on their molecular characteristics using Fitch-Margoliash algorithm. High genetic variations among the inbred lines indicates the presence of different heterotic groups, while low level of genetic variability within the inbred lines indicates that they met the assumption of homozygosity of their loci to enable further diallel crosses to be made for analysis of their combining ability. It is therefore expected that high heterosis in yield and its components could be obtained from crosses among those inbred lines belonging to different heterotic groups.