Comparison and correlative analysis of growth traits in young Robinia pseudoacacia clones.

Eleven elite clones of Robinia pseudoacacia, selected from Hungary, South Korea, Henan Province and the local county Yanqing of Beijing , were planted in Yanqing County in April, 2008 to investigate their growth performance in Yanqing Region of Beijing. Physiological and biochemical traits, such as net photosynthetic rate, chlorophyll and soluble sugar contents were measured. In addition, multiple morphological characters, such as height and basal diameter had been annually recorded for 3 years.Tukey's multiple comparison analysis indicated that clones of Hungary H2, South Korea K2 and K4, Henan 8048, and a local Yanqing 2N were superior in height and basal diameter, which distinguished them from other clones. Yanqing 2N (12.92 ±0.46) 滋mol/ (m2·s), Henan 8044 (12.7 ±0.21) 滋mol/ (m2·s), and Hungary H2 (11.78 ±0.24) 滋mol/ (m2·s) showed higher net photosynthetic rate than others. Henan 84023, South Korea K2, and Henan 8048, in that order, had the highest content of soluble sugars (68.97 ±8.61) mg/ g, reducing sugars (111.69 ±6.85) mg/ g, and free amino acid (426.4 ±5.3) 滋g/ g. Hungary H2 clone had the highest contents of both chlorophyll a and chlorophyll b,and the mean values were (3 512.3 ±8.7) and (3 824.9 ±118.1) 滋g/ g ,respectively. The highest carotenoid content was found in Hungary YDL (532.7 ±13.9) 滋g/ g. Except for a significant correlation (P 0.5) between chlorophyll content and the first year plant height, analysis showed no significant correlations between other physiological or biochemical traits and morphological characters. The results suggest that Hungary H2, South Korea K2 and K4, Henan 8048 and the local Yanqing 2N are the most recommended R. pseudoacacia clones for plantations in Yanqing County of Beijing. The current clone selection still highly depend on the measurement on plant height, basal diameter and other morphological characters.