Morphology and leaf nutrition of introduced Robinia pseudoacacia clones

Morphological characteristics, rooting ability, growth and leaf nutrition at age 3 years were studied on 13 clones of Robinia pseudoacacia, of which 2 were from China (2N and 3-I), 2 from Hungary (H1 and H2) and 9 from Korea. There were significant differences in growth and morphological characteristics among clones, but not in the contents of crude protein and crude fiber in the leaves (P0.05). Clones B and G recorded the fastest height growth and basal diameter, while clone H1 was the slowest. Clone H2 had the largest leaflets, three times as large as other clones, but K4 had the heaviest dry weight per 100 leaflets because it had the thickest leaves. The 13 clones can be divided into four classes (1-3,13-17, 15-23, 21-25) by the number of leaflets per compound leaf. There were significant differences in the thorn size; H2, with the largest leaflets, had the smallest thorns. All clones produced roots; clones 2N, K5 and B had more number of adventitious roots, while clones K3, K4 and H1 had less. Correlation between content of crude protein and length × width of leaf was positive (P0.05), while correlation of content of crude protein with number of leaflets per compound leaf, rachis length of compound leaf and thorn length were negative (P0.01). Plant height and basal diameter were positively correlated with each other (P0.01) and negatively correlated with base width of thorn (P0.05).