Analysis of genetic diversity in Argentinian heterotic maize populations using molecular markers
Over the past three decades, traditional Argentinean Orange Flint maize cultivars have been replaced by the higher yielding U.S. Yellow Dent germplasms. However, fint cultivars are potentially resistant to biotic and/or abiotic stress. Thus, knowledge of genetic diversity and relationships among fint inbred lines would help reduce genetic vulnerability and broaden the genetic base of crops in national improvement programs. In this study, we report the analysis of 25 inbred Orange Flint germplasms and one dent using 21 microsatellite markers or Simple Sequence Repeats (SSR). The aim was to assess genetic diversity among these accessions and evaluate the usefulness of SSR markers for defning heterotic groups in temperate germplasm. Genetic diversity values for fint germplasm (25 inbreeds) was relatively high. The number of alleles per locus was 5.14 and expected heterozygosis (He) was 0.68. When testing for genetic differentiation among the four heterotic populations established by topcross, twelve loci from a total of twenty-one displayed signifcant P-values. Even though we cannot observe a signifcant agreement between groupings based on topcross and clustering based on molecular data. On the other hand, Bayesian grouping (STRUCTURE software) performed better when compared to the clustering based on genetic distance (UPGMA-Modifed Roger s Distance).