Microsatellites and phenotypic characteristics used to select soybean lines in a Brazilian university breeding program
Plant breeders need to understand the genetic diversity and relationships between genotypes to choose parents of segregating populations. We evaluated the genetic diversity of 35 soybean genotypes and determined their potential as parent lines in breeding programs by analyzing their agronomic traits and microsatellite markers. Phenotypic analysis was carried out in the field at Fazenda Capim Branco, a research station of the Federal University of Uberlândia. Nine microsatellite markers and seven agronomic traits in were evaluated in 35 conventional soybean genotypes. Genotypes were grouped by UPGMA and Tocher cluster analyses, and molecular analysis was used to calculate polymorphism for each microsatellite locus. Nine microsatellite markers amplified 26 alleles, ranging from two to four. Polymorphism varied between 0.29 and 0.66, and averaged 0.44. The number of days to maturity was the characteristic that contributed the most to yield (29.44%). Seven potential parents (G11, G12, G16, G21, G22, G26 and G33) had average grain yields higher than 5000 kg ha-1. UPGMA and Tocher methods identified groups from the matrix of phenotypic and molecular data. Hybrids of G11, G12, G16, G22, G26 and G33 genotypes segregated promising populations with superior genetic variability.