Phenotypic diversity of soybean [Glycine max (L.) Merr.] accessions in the Philippines for utilization

An increasing trend of soybean production and consumption has been seen in the Philippines. To assess the potential of the soybean germplasm for utilization, diversity of the Philippine soybean collection was established. High diversity was marked on 17 out of 29 qualitative characters, which include plant growth habit, leaf blistering and flower standard color. Phenotypic diversity indices (H') of 92 soybean accessions averaged at 0.62. This aside, traits identical to a variety of soybean with superior characters were all present in the soybean germplasm collection. Using simple matching similarity coefficient, cluster analysis separated the different accessions into 12 distinct clusters at 62% similarity. Categorical Principal Component Analysis (CATPCA) showed that two independent components accounted for 35.36% of the total variation of the qualitative morphological characters. Factor loadings for each component showed the morphological characters, such as pubescence color, flower wing color, and seed coat color, that were contributing to the high projections in the two principal components. Accessions with vigorous seedlings were also observed. With the marked trait diversity, the soybean collection could be potentially used directly and for breeding purposes. Consequently, to uncover further the potential of our genetic resources at hand, the remaining germplasm accessions at NPGRL should be characterized and evaluated.