Evaluation of Genetic Diversity for Agronomic, Morphological and Phenological Traits in Soybean

In order to study the genetic diversity of yield and its components, and also some of morphological and phenological characteristics, 364 soybean genotypes were studied, based on an augmented design with three checks and six blocks, in Seed and Plant Improvement Institute, Karaj, Iran, during 2003-04. These genotypes ( 35 determinate, 183 semi determinate and 149 indeterminate, most of them were from 1-4 maturity groups) were includedmostly imported genotypes and some of germ plasm from national breeding programs. Results showed that there were highly significant differences among genotypes for all studied characteristics, because they were from different maturity groups. Number of pods in branches, number of branches and number of sterile nods in the beginning of maturity stage, had high phenotypic coefficients of variations. The percent of oil and protein and number of nods in the beginning of seed constitution stage had low phenotypic coefficients of variations. The results of simple correlation showed that the biomass, number of seeds and number of pods per plant had high correlation with seed yield per plant. The traits related to growing stages such as days to complete flowering and days to complete maturity, had significantly positive correlation with plant height (P < 1%). Based on cluster analysis, 364 genotypes were classified in three groups for yield and its components traits. The discriminate functions for three groups, obtained by cluster analysis, were also formulated. Two functions described 100% of variance among genotypes. The most important characters for distinguishing these groups were number of seeds per plant, seeds yield and biological yield.