Analysis of genetic diversity in Argentinian heterotic maize populations using molecular markers

MORALES YOKOBORI,L.; DECKER, VG.; ORNELLA, L.

CIENCIA E INVESTIGACIóN AGRARIA

PONTIFICIA UNIVERSIDAD CATOLICA CHILE

Año: 2010 vol. 37 p. 151 - 160

0304-5609

Over the past three decades, traditional Argentinean Orange Flint maize cultivars have been replaced by the higher yielding U.S. Yellow Dent germplasms. However, flint cultivars are potentially resistant to biotic and/or abiotic stress. Thus, knowledge of genetic diversity and relationships among flint 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 defining heterotic groups in temperate germplasm. Genetic diversity values for flint 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 significant P-values. Even though we cannot observe a significant 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-Modified Roger’s Distance).