Abstract

The aim of this study was to estimate the genetic diversity in 74 RR soybean cultivars from different Brazilian breeding programs. Analyzes were based on multivariate statistical techniques from phenotypic characteristics and microsatellite molecular markers (SSR). Ten agronomic traits were used in the analysis of the Euclidean distance, Tocher’s clustering, UPGMA clustering and principal component analysis. Eighty-six of 100 SSR primer-pairs studied were selected based on their polymorphism information content, and analyzed using Jaccard Coefficient and UPGMA clustering method. The cultivars were clustered into seven groups according to the UPGMA and Tocher’s methods, based on agronomic traits, while molecular analysis identified six groups. The phenotypic distances ranged from 0.46 to 9.79 and the dissimilarity measurements, based on SSR molecular markers, ranged from 0.07 to 0.73. Both results from agronomic traits and molecular markers showed that there is genetic variability among the RR cultivars and that the Monsanto breeding program has the most divergent germplasm. The analyzed agronomic traits and the chosen SSR markers were effective in assessing the genetic diversity among genotypes, besides proving to be useful for characterizing genetic variability of soybean germplasm.

Key words: Glycine max, genetic variability, phenotypic characteristic, SSR markers.

Abbreviation

Abbreviations: CTAB, Cetyl trimethylammonium bromide; GMO, genetically modified organism; PCR, polymerase chain reaction; SSR, simple sequence repeat; UPGMA, unweighted pair group method with arithmetic mean; RR soybeans, roundup ready soybeans.