Studies On Relationship Between Canopy Structure And Fruit Quality For Three Tapes Of Apple Tree Shape

The experiment had studied the relationship with canopy structure, relative light radiation intensity distribution, the fruit yield and quality within three canopy shapes of'Fuji'Apple Tree ( Malus domestica Borkh cv. Red Fuji ) by using the methods of combining field biological and ecological investigation and indoor analysis. The three canopy shapes were weeping willow shape, small canopy shape and delay-open central leader shape. This study provided theoretic base and instructively technical measures for reconstructing tree shape in denser planted orchards, cultivating reasonable population structure, improving fruit quality, maintaining continually high quality and fertility of orchards. The main results were summarized as follows:1. The branches in weeping willow shape all dropped downhill and more than 86.6% of them were short shoot while the ratio was only 68.3% and 59.3% in small canopy shape and delay-open central leader shape. The effect was not obvious in the delay-open central leader shape although the condition of illumination had improved.2. The TR and TD in the crown of the weeping willow shape were 0.18 and 0.16 and were significantly higher than that in small canopy shape and delay-open central leader shape. The K was only 0.675 while it was 0.848 and 0.830 in small canopy shape and delay-open central leader shape, therefore the illumination were better in the middle and lower layers of weeping willow shape than in other two shapes. On the contrary, The leaf area index was significantly lower. 3. The distribution of relative light intensity in the canopy gradually descended from upper to lower layer, from outer to inner layer. But the differences in horizontal direction were not as obvious as in vertical direction. The ratio of area of lower efficiency light was 13.89%,14.44% and 21.67% in weeping willow shape, small canopy shape and delay-open central leader shape.4. The yield and quality were quite different in different canopy shapes. The yield, pigmentation, soluble solids, soluble sugar, solids-acid ratio and sugar-acid ratio in weeping willow shape were significantly higher than those in small canopy shape and delay-open central leader shape, while the firmness, fruit water content and titratable acidity were significantly lower. The current of mean fruit and the proportion of over 80 fruit were better in weeping willow shape than in other two shapes.5. The content of endogenous hormone in branches and leaves was different in diverse shapes of branches. It was the highest of the content of IAA, ZR and GA in downward branches and the lowest in upright branches, while the content of ABA was opposite. The content and distribution of endogenous hormone had an important effect on the modality of branches.The results illustrated that the relative light radiation intensity distribution and the fruit yield and quality in weeping willow shape were all better than those in small canopy shape and delay-open central leader shape. The optimum range of relative light intensity for good quality in'Fuji'apple was 45% ~ 80%.