| In this study, Vitis vinifera cv. Thompson Seedless and its natural variations were used as materials to investigate fruit characteristics, including grape polyphenols such as resveratrol and polyphenol oxidase（PPO） activities. Moreover, the natural heat and light stress on photosynthesis characteristics were studied to evaluate the bio-ecological characteristics of different clones in the field cultivation conditions in Shanshan of Xinjiang. Grape bunch treatment of V. vinifera cv. Thompson Seedless was also carried out to promote the production of high-quality fruit. The results provide the basis for breeding new seedless varieties and have a reference value for the promotion of its commercial fruit production and optimizing the local economic development model. The main results were as follows:1. Fruit characteristics analysis demonstrated that there were a wide range of morphological differences among natural variation. The berry sizes of clones were greater than that of control. Berry mass of Big-berry Thomson Seedless, W3, Long-bunch Thompson Seedless, Long-berry Thompson Seedless, and W7 were 2.08, 1.98, 1.91, 1.39 or 1.33 times of that of the control respectively. The berry compression resistances of Long-berry Thompson Seedless and Big-berry Thompson Seedless were 1.23, 1.01 times of that of the control respectively. The berry detachment force of Long-berry Thompson Seedless, Big-berry Thompson Seedless, W7 and W3 were 1.59, 1.05, 1.01 or 1.01 times of that of the control respectively. The total soluble solid of greater berry clones （viz W3, Big-berry Thompson Seedless, Long-berry Thompson Seedless） were excess the national standard requirements （18%）. Comprehensive evaluation showed that the berry characteristics of the clones were better than the control and a significantly different fruit or fruit type of‘Thompson Seedless’variation was probablely obtained by the clonal breeding.2. Biochemical analysis indicated that the contents of resveratrol in pericarps were 4.86 times higher than in whole berries. The 5 high resveratrol clones in berries were W2, W3, W6, Long-bunch Thompson Seedless and W7 with the contents of 3.56, 2.88, 2.56, 2.10, 1.97μg.g-1, respectively. The average concentration of phenolic compounds in pericarps (401.94μg.g-1) was higher than the whole berries (277.53μg.g-1). The clones of lower concentrations of phenolic compounds were Long-berry Thompson Seedless, W3, Big-berry Thompson Seedless and W8. The PPO activity in average of pericarp was 2.81 times of the whole berry. The clones of lower PPO activity were W7, Long-bunch Thompson Seedless, W3, W8 and Long-berry Thompson Seedless, respectively. Comprehensive analysis indicated that the higher levels of resveratrol were in the variants of W3, Big-berry Thompson Seedless and Long-berry Thompson Seedless, but total phenolic content and PPO activity in these clones were relatively low, which could be used for further table and raisin grape variety breeding. Moreover, the measurement of PPO activity and other indicators would provide a basis for breeding new table and raisin varieties of‘Thompson Seedless’line.3. Photosynthesis characteristics assay displayed that the daily average net photosynthesis rates （Pn） of the clones tested, including, W3, W7, Long-bunch Thompson Seedless and Long-berry Thompson Seedless, were 1.52, 1.43, 1.32, 1.15 and 1.13 times higher than that of the control. In addition to Long-bunch Thompson Seedless, Long-berry Thompson Seedless and the control, there was no significant midday depression of photosynthesis on other clones. The Pn and other indicators of these varieties （variants） were in positive correlation. The temperature was the main factor that affects grape photosynthesis, followed by humidity. However, stomatal conductance （Gs）, light and other factors were weak on photosynthesis. The order of the correlation between the ecological factors and Pn were the air temperature （Tair） > leaf temperature （Tleaf） > vapor deficit at the leaf surface （VpdL） > Tr > Gs >PARi. The daily average light use efficency of the clones were 1.23 times than that of the control, among which W3, Long-bunch Thompson Seedless and W7 were 1.58, 1.32 and 1.31 times as higher than controls. The results showed that the light use efficency of the clones had an increased tendency, and the clones maintained a high level of light use efficiency （LUE） with time extension. The intrinsic water use efficiency on average was 1.77 times as higher as the control, suggesting that the water use efficency of the clones were higher than that of the control. This might be one of the reasons to increase the photosynthetic rate and fruit berry. Comprehensive analysis revealed that the photosynthetic characteristics of the variants were better than that of the control, and had the advantages to adapt to local climate （high temperature, strong radiation and low air humidity） conditions. Analysis of photosynthetic index of natural variation in Thompson Seedless would provide a basis for selection variety from its natural variations.4. Bunch treatment analysis showed that the bunch dipping treatment with a combination of different concentrations of GA3, CPPU and KH2PO4 were much better than that of the control on single berry mass, berry detachment force, compression resistance and fruit soluble solids, which could effectively improve the fruit commodity. Comprehensive analysis on the 4 indicators indicated that the combination of GA3 53.78 mg?L-1, CPPU 2.63 mg?L-1, KH2PO4 5 mg?L-1 to treat bunch 7-10 d after flowering could obtain ideal results. The single berry mass could reach to 3.93 g, the berry detachment force was 4.74 N, the berry compression resistance was 17.95×105 Pa and solube solids content was 19.37%, which were 1.78, 1.58, 1.40 and 1.08 times compared to the controls, respectively. |
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