Accurate data and relevant insights on parental corn inbred lines’ and hybrids’ genetic purity and diversity are essential for hybrid development and seed production. Here, the genetic purity and diversity of 19 parental yellow corn inbred lines were assessed using SSR markers. A total of 91 SSR markers were utilized, of which 61 were highly polymorphic and had high polymorphism information content value (PIC = 0.379). Genetic purity and diversity parameters were calculated from the generated SSR marker data. Observed pairwise genetic distances ranging from 0.257 to 0.808 implied high genetic dissimilarities among the accessions. Cluster analysis separated the parental lines into three distinct subclusters, which can potentially be a basis for generating heterotic groupings among the parental lines. Eight (8) out of the 19 parental lines showed considerable residual heterozygosity of ≤10%. Inbred line CML 431 displayed complete homozygosity across all 61 SSR markers. Inbred lines that have residual heterozygosity of >15% need purification through further breeding and selection. Out of the resultant F1 hybrids analyzed, only four (4) showed genetic impurity of ≤10%. It may be attributed to the intrinsic genetic impurity of parental line CML 452 (21.67%). In contrast, hybrids generated from two genetically pure parents (e.g., CML 431 and CML 575) showed low to no off-types. Overall, genetic purity and diversity determination of promising parental lines can be valuable for future yellow corn breeding programs in the Philippines.
corn, SSR markers, genetic purity, genetic diversity, hybrid development
The genotyping strategy employed in the study proved cost-efficient and effective in terms of identifying whether the corn genotypes are genetically pure or contaminated. Corn breeders can utilize the generated clusters as a basis for designing cross-combinations. Finally, the achieved set of SSR markers determined can help further assess successful hybridization among the corn genotypes used in this study.