Genetic divergence among sweet corn lines estimated by microsatellite markers.

The purpose of this study was to analyze the genetic diversity of 15 sugary-1 sweet corn lines by microsatellite markers. One hundred pairs of simple sequence repeat primers that were mapped for field corn were tested. Of these primers, 15% were polymorphic, and all were selected for the evaluation. These primers identified a total of 39 alleles among the 15 loci that were evaluated. The number of alleles per locus in the genotypes ranged from 2 to 4, with an average of 2.60 alleles per locus; the highest number of alleles was observed at the loci Bnlg1083, Umc1241, and Umc1590. The occurrence of null alleles at locus Umc1363 was evident only in line DN44. The proportion of polymorphic loci was the highest in lines DN17.1 and DN6 (73.33%), whereas lines DN47, DN23, and DN28 were more monomorphic than other lines. The loci Bnlg1083 and Umc1506 were polymorphic in 8 and 7 lines, respectively, indicating that these loci might be effective and promising for the identification of polymorphism in other sweet corn lines. The genetic diversity calculated by Rogers' genetic distances indicated the lowest genetic similarity between lines DN9 and DN28 (0.7603) and the highest similarity between lines DN19 and DN6 (0.3724). The dendrogram obtained by the unweighted pair-group method based on arithmetic averages indicated the formation of 4 major groups, showing the crossing of the genotypes DN19 and DN6 with DN8 as a possible alternative for the expression of heterozygosis.