Comparative Analysis on Growth and Photosynthetic Characteristics of Hevea brasiliensis Budding Clones

In order to select and cultivate high-quality Hevea brasiliensis clones with efficient utilization of photosynthetic products, 11 H. brasiliensis clones were used in a high clone trial. The growing characteristics, photosynthetic traits, and physiological parameters in 1.5-year-old seedlings were determined and analyzed. The growth and photosynthetic physiology characteristics of different clones of H. brasiliensis were compared by ANOVA and correlation analysis. The results showed that the differences in stem diameter, plant height, extended unit number, transpiration rate, stomatal conductance, and instantaneous water use efficiency among the clones were statistically significant among clones. The differences in photosynthetic traits of net photosynthetic rate and intercellular CO₂ concentration were significant among clones as well. The phenotypic variation coefficient of 8 indexes ranged from 9.96% to 40.54%, and the relative range ranged from 24.06% to 102.70%. Correlation analysis indicated that pairwise significant positive correlation was found among the 3 growth traits. There was no significant correlation among photosynthetic physiological parameters, stem diameter and plant height. Among the tested H. brasiliensis clones, No.614 had the best growth performance, followed by No.617 and No.621, No.618 and No.621 clones had higher photosynthetic and water use efficiency.