Variation of Korean Soybean [Glycine max (L.) Merrill] Varieties based on Leaf-Related Characters

This study was carried out to investigate the variation of leaf-related characters and classify varieties of 172 Korean soybean [Glycine max (L.) Merrill] released from 1913 to 2013 using cluster analysis. The leafrelated characters evaluations were also compared according to released year and utilization types. The results obtained from the present study are summarized as follows: variation coefficient of leaf characteristics of Korean soybean varieties was 15.27% in leaf length, 23.59% in leaf width, 24.01% in leaf width ratio, 16.67% in leaf thickness, 32.65% in leaf area, 20.35% in leaf dry weight, 37.02% in leaf area ratio, 21.9% in petiole length, and 47.18% in petiole weight. Principal component analysis (PCA) of nine leaf characters revealed that the cumulative contribution from the first to the third main component was 84.9%, and it was possible to classify Korean soybean varieties only with the third main component. A total of 6 clusters were formed with an average distance of 1.5. The total number of varieties were classified as follows: 66 (38.4%) in cluster I, 8 (4.7%) in cluster II, 8 (4.7%) in cluster III, 25 (14.53%) in cluster IV, 2 (1.2%) in cluster V, and 63 (36.62%) in cluster VI. About 75.1% of the total number of varieties belong to cluster I and VI. No cultivars produced before 1980 were found in cluster III and V and no cultivars in 1980s were included in III, IV and V, and none of the cultivars of 1990 belong to cluster V. Varieties released after the 2000s were well represented in each cluster. Comparison of leaf characters based on utilization types showed that sauce & paste belong both in clusters I and VI, bean sprout in I and VI, cooking with rice in I, and vegetable & earlymaturing in VI. Growth and leaf-related characteristics traits are poor in cluster V and good in cluster VI.