Abstract: The importance of carbon input in tea productivity can be appreciated from the fact that 95% of the dry weight of the plant is derived from photosynthesis. Therefore, an increase in net photosynthesis and more efficient partitioning are logical steps for increasing productivity, which was subject to the tea genotypes. The photosynthetic parameters in leaves of 52 tea cultivars were determined under field conditions, and studied by using phenetic classification, principal component, cluster, discrimination analyses. The results showed that there were significant differences (P<0.01) in net photosynthesis rate (P_n), transpiration rate (T_r), stomatal conductance (G_s), intercellular CO₂ concentration (C_i), water use efficiency (WUE) among the tested cultivars. The first three principal components were analyzed and their cumulative contribution of variance accounted for 96.98%. P_n, T_r, and G_s were the main factors in the first principal component. WUE and C_i were the main factors in the second and third principal com-ponents respectively. Fifty two tea cultivars were clustered into five groups based on P_n, T_r, G_s, and WUE. The group I including 15 tea cultivars with high photosynthesis rate, medium transpiration rate, lower stomatal resistance and high water use efficiency could be used for improvement of tea cultivars. Then, with discrimination analysis, the parameters of P_n, T_r, G_s, and WUE greatly affecting the classification were selected, and five discrimination models with better distinguishing ability were set up.

Key words: Tea (Camellia sinensis), Photosynthetic characters, Phenetic classification, Cluster analysis