Study On The Relation Of Bearing Branch Characteristics And Fruit Quality In’Dangshansu’ And ’Yali’ Pears

The growth of bearing branch and bearing branch group is the base of the output and the quality in pear tree. Different types of bearing branch, bourse shoot, bearing branch group are closely related to pear tree trim, but these researches were still very defective. The cv.’Dangshansu’pear and the cv.’Yali’pear are two fine traditional pear varieties in our country, however, the question of quality dropped was increasingly prominent in recent years. In this study, the cv.’Dangshansu’and the cv.’Yali’ are used for materials, the pear fruits from different types of bearing branch, bourse shoot and branching times of bearing branch group were carried on the quality analysis during the mature in order to provide the theory basis for tradition pear quality improvement in our country. The main results are as follows:1. The effect of different type branches on the fruit quality were studied, the result indicated that The long, medium and short fruit branches of different tree age cv.’Dangshansu’had different influence to the quality. In12year-old cv.’Dangshansu’(full fruit initial period), the single fruit weight of long fruit branches was lower5.2%than the short fruit-bearing branches, the soluble solid content of short fruit-bearing branches was higher than2.9%and3.1%compared to the long fruit branches and the medium fruit branches respectively. But in28year-old cv.’Dangshansu’(full fruit period), the single fruit weight of long fruit branches obviously was higher10.7%than the short fruit-bearing branches, the soluble solid content and the total soluble sugar of long fruit-bearing branches was higher4.5%and5.1%compared to the short fruit branches respectively. The sepal saving rate of long fruit branches in12year-old cv.’Dangshansu’was obviously higher above19.6%compared to the short fruit-bearing branches, but in28year-old trees, the sepal saving rate has not remarkable difference among the long, medium and short fruit-bearing branches. And the fruit hardness, titratable acidity, stone cells and Vitamin C content have not obvious difference among the long, medium and short fruit-bearing branches of12year-old cv.’Dangshansu’, but the fruit hardness and stone cells of short fruit-bearing branches were higher than long fruit-bearing branches in28year-old cv.’Dangshansu’, and further section staining observation, discovered that the short fruit-bearing branches fruit the core compared to the long fruit branches fruit slightly big, around the short fruit-bearing branches core stone-cell obviously increases, assumes the radiated distribution. This indicated that the long fruit branches should be kept for bearing when the tree age is older.2. The effect of length of bourse shoot and coarseness of bourse shoots on the fruit quality in cv.’Dangshansu’and cv.’Yali’were studied, the results showed that length of bourse shoot and coarseness of bourse shoots were remarkable extremely related to the soluble solid content and the single fruit weight, and the fruit hardness and titratable acidit had no obvious difference among different bourse shoots. The fruit increases along with the length of bourse shoot, the single fruit weight of>60cm length of bourse shoot group is higher above52.6%compared to the10-20cm group, when coarseness of bourse shoot in cv.’Dangshansu’ were3.1-4.5mm and the length of bourse shoot>5mm, the single fruit weight increases obviously, the soluble solid content and total soluble sugar obviously increases. In cv.’Yali’, the length of bourse shoot was below1cm, with the length of the bourse shoot increase, the single fruit weight and the soluble solid content increases gradually, the fruit weight of length of bourse shoot>10cm increases37.7%compared to the length of bourse<1cm; coarseness of bourse shoot between3～5mm, the single fruit weight increases along with the coarseness, the single fruit weight of coarseness>6mm increases32.1%than<3mm; The soluble solid content was the highest in5.1～6cm group, and was higher above14.5%compared to the<3mm group; stone-cell content is highest in<3mm group. The results suggested that the length and the coarseness of bourse shoots should be>50cm and>4.5mm respectively in cv.’Dangshansu’ and the length and the coarseness of bourse shoots should be>10cm and>5mm respectively in cv.’Yali’in order to produce high quality and big pear fruits.3. The effect of branching times of bearing branch group on the fruit quality in cv.’Dangshansu’and cv.’Yali’were studied, the results indicated the branching time of bearing branch group was extremely remarkable inverse correlation (r=-0.4549, r=-0.3414) to the soluble solid content and the single fruit weight in cv.’Dangshansu’, and in cv.’Yali’branching times of bearing branch group extremely remarkable inverse correlation (r=-0.4469) to the soluble solid content, but had no correlation to the single fruit weight. The fruit weight and the soluble solid content were the biggest by1-2branching time of bearing branch group. When comparing>8times with1-2branching times, the single fruit weight dropped97.5%, the soluble solid content and the total soluble sugar dropped11.6%and14.7%respectively, In cv.’Yali’, the single fruit weight had no obvious difference in different branching time of bearing branch group, but the soluble solid content dropped gradually with the increase of branching times, and had no difference in1-2times and3-4times. The stone-cell content increased along with the increases of branching times of bearing branch group in cv.’Dangshansu’and cv.’Yali’, the fruit hardness and titratable acidity had no obvious difference. The above results suggested that the branching time of bearing branch group should not exceed6times and take1-2times as optimum in cv.’Dangshansu’, and that the branching times should not exceed8times and take1-4times as optimum in cv.’Yali’in order to produce the high quality and big pear fruits.