Genetic Diversity among Tropical Provitamin A Maize Inbred Lines and Implications for a Biofortification Program.

Insights into the diversity and relationships among elite breeding materials are an important component in maize improvement programs. We genotyped 63 inbred lines bred for high levels of provitamin A using 137 single nucleotide polymorphism markers. A total of 272 alleles were detected with gene diversity of 0.36. Average genetic distance was 0.36 with 56% of the pairs of lines having between 0.30 and 0.40. Eighty-six percent of the pairs of lines showed relative kinship values <0.50, which indicated that the majority of these provitamin A inbred lines were unique. Relationship pattern and population structure analysis revealed presence of seven major groups with good agreement with Neighbour Joining clustering and somewhat correlated with pedigree and breeding origin. Utilization of this set of provitamin A lines in a new biofortification program will be aided by information from both molecular-based grouping and pedigree analysis. The results should guide breeders in selecting parents for hybrid formation and testing as a short-term objective, and parents with diverse alleles for new breeding starts as a long-term objective in a provitamin A breeding program.