Abstract
Fifty-four accessions of local soybean strains were collected from villages in the western part of the Shikoku Mountains and examined for morphological traits associated with growth, yield, seed size and seed shape. They included 25 yellow, 17 black, 2 brown and 10 green seed-coat color strains. Nested analysis of variance revealed large morphological variation among strains within the seed-coat color groups but hardly any significant difference among the color groups except seed weight. Significant positive correlations were found among growth and reproduction related characters except seed weight. Seed weight was negatively correlated with those characters, indicating a trade-off corresponding to the resource allocation to growth and maturation of seeds. There was a significant negative correlation between altitude of collection sites and seed shape (height/thickness), suggesting that altitude can be a factor causing diversification of seed morphology. Principal component analysis (PCA) was carried out on eleven morphological traits. No clustering in regional populations was shown on the plane determined by the first two principal components except in Hirota Village (old name), in Ehime Prefecture. There was a positive correlation between genotypic distance revealed by random amplified polymorphic DNA (RAPD) analysis and phenotypic distance. However, a large phenotypic variation was observed even between genetically very closely related strains.
