Estimation of Phenotypic Diversity of Soybean Genotypes Available in Sri Lanka for Varietal Improvement

Soybean is an introduced crop to Sri Lanka with extensive cultivation increase during 1970s with the intervention of developmental programs. But still the requirements for the animal feed industry is importing due to non availability of oil processing within the country. The genetic diversity studies play a vital role in an effective plant breeding program in order to utilize and manage existing germplasm. Present study aim to understand the genetic diversity received from plant Genetic Resource Center, Gannoruwa for the future breeding needs. 65 genotypes of soybean were characterized and evaluated in the research field of Grain legumes and Oil Crops Research and Development Center, Angunakolapelessa during 2012/13 Maha season. Principal Component analysis reveals that three components explained 72% of total variability. Also in the cluster analysis genotypes were grouped in to 5 clusters, where 20, 17,15,9 and 4 was the genotype numbers in each cluster. The reference variety Pb 01, which is the most popular variety of soybean in Sri Lanka, was in the main cluster which contains 20 genotypes. Cluster group 3 has shown the highest mean values for grain yield per plant, terminal leaflet width and terminal leaflet width. Therefore to improve the variety PB 01 use of genotypes from the cluster group 3 may be possible with considering the other qualitative characteristics