Resumo

GILL-LANGARICA, Homar Rene et al. Morpho-Agronomic and genetic characterization of soybean bred germplasm. Agric. Téc. Méx [online]. 2006, vol.32, n.3, pp.281-294. ISSN 0568-2517.

The analysis of genetic diversity in soybean germplasm is important for the identification of contrasting and complementary parental genotypes for its utilization in a given region. In this work nine introduced and eight local cultivars as well as 94 experimental soybean lines were characterized with 18 agronomic traits and AFLP molecular markers in order to determine the genetic relationships and genetic diversity in the germplasm. During 2004 at the Experimental Station South of Tamaulipas, Mexico, a subset of 82 genotypes was evaluated under field conditions. Based on results of a principal component analysis, color of pod and pubescence, number of pods with one and with two seeds and seed weight were the most descriptive agronomic traits. Using those traits, genotypes were then classifi ed in three groups. Group I included genotypes with grey pod and pod pubescence, intermediate number of pods with one and two seeds and low seed weight and seed yield; group II included genotypes with brown pods and pod pubescence and high seed yield; group III with genotypes of intermediate values for all traits. The dendrogram constructed based on AFLP data showed three major groups of genotypes with genetic dissimilarity from 7.25 to 8.25%. Group I included lines derived from cultivars Jupiter and Santa Rosa, local and introduced cultivars; group II included introduced cultivars, experimental lines derived from Jupiter and local cultivars; group III only included experimental lines. Cultivars Jupiter and Santa Rosa generated 38 and 37% of the total genetic variability, respectively. Principal component analysis from AFLP data did not separate introduced from local cultivars, although experimental lines derived from Santa Rosa and Jupiter were distinct from their parents. An analysis of molecular variance showed reduced genetic diversity. No significant association was found between genetic and agronomic variability patterns in the genotypes characterized. Broadening the soybean genetic basis of the germplasm in Mexico, is urgently needed.

Palavras-chave : Glycine max (L.) Merr; genetic diversity; AFLP molecular markers.

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