Study On Pruning Techniques Of Camellia Oleifera Based On The Analysis Of Canopy Micro-climate

As matters stand presently, the fruit yield and quality of Camellia oleifera is low. In order to determine a set of practical pruning techniques inproving the fruit yield and quality of Camellia oleifera, with Xiang-Lin high-yield choiceness clones as test material, the research content includes following aspects. The correlation between the canopy micro-climate during different periods and the fruit characters were analyzed. The growth characteristics of branches and fruiting habits were investigated. The plastic of Camellia oleifera and the chemical control technologies of tree body were also studied.The results showed as follows.1. The regional distribution of canopy micro-climate during different periods had significant difference and certain regularity. In the vertical direction, with the increase of tree canopy, light intensity and temperature gradually increased, but the humidity gradually reduced. Among them, the maximum difference value of light intensity could reach 847.71 μmol·m-2·s-1, and temperature was 1.13℃, while that of the humidity could reach 2.16%.In the horizontal direction, the light intensity and temperature outside canopy was higher than that of inside, humidity distribution instead. Among them, the maximum difference value of light intensity could reach 691.96 μmol·m-2·s-1, and temperature was 0.96℃. As for the humidity, the maximum difference value could reach 1.31%. On the same canopy layer, the highest light intensity and temperature were southward. The lowest were northward, and humidity was on the contrary. Among them, the maximum difference value of light intensity could reach 467.27 μmol·m-2·s-1, and temperature was 1.17℃, while that of the humidity could reach 0.69%.2. The fruit characters varied considerably but regularly in different canopy regions as similar with canopy micro-climate. The range of yield was from 0 g.m-3 right to 2202.70 g.m-3.The range of oil content ratio in dry kernel was from 20.08% to 39.77%. The range of oil content ratio in fresh fruit was from 2.17% to 7.49%. The range of oleic acid content was from 75.60% to 81.24%, while range of the palmitic acid content declined from 10.23% to 8.85%. A Significant correlation was observed between the fruit characters and canopy micro-climate during different periods. The highest correlation coefficient between yield and light intensity was during January to February, which could reach 0.960. In the same period, the highest correlation coefficient between yield and humidity was 0.929. As for other fruit characters, they had the highest average correlation coefficient with canopy micro-climate during October.3. The amount of branches and leaves had also significant difference in different regions within the tree canopy. The amount of branches was the most in southward, accounting for 14.84% of the total amount of branches within the canopy. While north direction had the least amount of branches, which accounted for 10.75%. The strong branches in upper layer accounted for 70% of the total amount of strong branches within tree canopy. But as for the lower layer, strong branches only accounted for 5%. Since the branches distribution, the leaf area coefficient was also of significant difference. Among them, the south direction had the maximum average leaf area coefficient, which could reach 11.35. But north direction with the minimum average leaf area coefficient was only 8.55.4. Through the analysis of fruiting habits, it was known that the annual branches with the length of 8～17 cm were easier to bear fruit. Among them, the growth and development of fruits with the long branches was the best. Compared with the short fruiting branches, the amount of flowers and fruits of the long fruiting branches increased by 118.52% and 99.40%, respectively. It also respectively increased fruit-set rate and final single branch yield by 39.99% and 144.43%.5. The open center shape could significantly affect the distribution of micro-climate within the tree canopy, which could make the distribution of micro-climate more uniform. The open center shape could also improve the yield of fruit in different regions. Compared with the control, the increase of the final yield was not significant, but it could significantly affect the oil content rayio in dry kernel and fresh fruit. And the fruit yield characters in the lower and inner within tree canopy of the open center shape were much more significantly affected. The oil content ratio in dry kernel and fresh fruit of lower layer increased 56.27% and 94.19%, respectively, compared with the control.In this way. the distribution of the fruit yield within the tree canopy in different regions was also more evenly.6. Different pruning methods would affect the length and diameter of annual branches, as well as the growth and development of fruit within the branches. Among them, the short cut clip did best. Compared with the control (sling put treatment), the amount of annual branches decreased. However, the amount of fruiting branches increased by 56.30%. The amount of flowers and fruits increased by 150.38% and 117.07%, respectively. The fruit-set rate also increased by 40.13%, as well as the final single branch yield, which increased by 303.68%.7. All the concentrations of brassinolides could affect the photosynthesis and fruit characters. The comprehensive effect with the concentration of 0.08 mg.L-1 was best. Picking time after spraying brassinolides a month later was optimum. At this time, the fruit characters were best. It could increase the final yield and oil content ratio in dry kernel by 3.01% and 54.82%. respectively, compared with the control. At the same time, the unsaturated fatty acid content increased by 2.63% and saturated fatty acid content decreased by 14.62%.Form what had been discussed above, it is recommended as follows. Firstly, as to the sapling, it is suggested to put their plastic for the open center shape. Secondly, as to the Camellia oleifera trees which have entered into the full bearing period, the short cut way of pruning should be used more. Meanwhile, the change of canopy micro-climate during January to February and October should be pay more attention to. Some artificial measures were needed timely, such as winter pruning and picking fruits in advance. During the oil conversion period (September), it is recommended to spray with the concentration of 0.08 mg.L-1 and pick fruits timely to achieve the maximum benefit.