Morphological Traits of Lotus japonicus (Regal) Ecotypes Collected in Japan

Forty-seven wild accessions of Lotus japonicus Regal (Japanese trefoil) indigenous to Japan were investigated for nine morphological characters. Average temperature and annual precipitation were negatively correlated with stem color and seed weight. On the other hand, latitude was positively correlated with these traits. Consequently, accessions from sites at higher latitudes with low temperatures and precipitation tend to have dark red stems and heavy seeds. Cluster analysis based on nine morphological characters classified 47 wild accessions into six major groups. Cluster I included four accessions of tall and erect plants. These plants are phenotypically similar to commercial variety ‘Empire’. Cluster II consisted of three accessions of creep plants with pale red stems. Cluster III contained 24 accessions that had average values for all morphological characters evaluated. Cluster IV included two accessions of erect plants with rounded leaflets and dark red stems. Cluster V included four accessions of small, creep plants with pale red stems. Cluster VI included seven accessions of small and erect plants, a phenotype that also applies to ‘Gifu B-129’, which is used as experimental strain worldwide. These data were deposited into LegumeBase, an online database (http://www.legumebase.brc.miyazaki-u.ac.jp/) supported by the National BioResource Project (NBRP) in Japan.