Study On The Technology Application Of Summer Pruning For The Fruiting Branch Groups Of Sand Pear Trellis Cultivation

The sand pear cultivar ’Niitaka’ (Pyrus serotina cv.Niitaka)> ’Kousui’ (Pyrus serotina cv.Kousui)、’Nijisseiki’(Pyrus serotina cv.Nijisseiki) and ’Housui’(Pyrus serotina cv.Housui) were used as experimental materials. The relationships between the coarseness of fruiting branch groups basis and the number of spurs, the number of spur leaves, as well as the weight of single fruit were investigated, the effects of different summer pruning on the growth of fruiting branch groups were studied, and the effects of different length sprouts cutting back on the base of fruiting branch groups, the formation rates of spurs, the amount of spur leaves, and fruit quality were discussed; The optimum technologies of summer pruning in the four kinds of the sand pear cultivar were summarized. The main results were as follows:(1)In four cultivars, there is a close relationship between the number of spurs and the base diameter of fruiting branch groups, especially in’Kousui’, when the base diameter of fruiting branch groups is about 0.9cm,the number of spurs is 9.3 on average per meter, and when the base diameter of fruiting branch groups is about 3cm,the number of spurs is 3.8 on average per meter;(2)Sprouts cutting back on the fruiting branch groups can effectively control the growth of base diameter in the fruiting branch groups and extend the working life of fruiting branch groups. In the cultivar of ’Niitaka’:the base diameter enlargement rate of fruiting branch groups reduced by 18.26% on average after sprouts cutting back;(3)Sprouts cutting back on the fruiting branch groups can significantly improve spurs’ formation rate of sand pear, The tested cultivar of ’Niitaka’ showed the most significant in the four cultivers, and’Housui’is next. When 8-12cm of sprout length was cut back on the fruiting branch groups of’Niitaka’, the spur formation rate increased 43.6% on average. When 8-12cm of sprout length was cut back on the two year fruiting branch groups and 18-22cm of sprout length was cut back on four year fruiting branch groups in’Housui’, the spur formation rates increased 30% respectively;(4) The results of treatments in this experiment were significantly different in single fruit weight and soluble solid contents in contrast with the controls. When 8-12cm of sprout length was cut back on fruiting branch groups, the average single fruit weight increased 60-70g and soluble solids content increased 0.72% in’Housui’(5) The workload of sprouts cutting back throughout the year varies with the different cultivars.3-4 times of sprouts cutting back on fruiting branch groups were needed in a year for ’Niitaka’ and ’Housui’, but for ’Nijisseiki’, only 2 times of sprouts cutting back on fruiting branch groups were needed in a year;(6) The number of spurs and single fruit weight were related with the base diameter of fruiting branch groups, the desirable base diameter of fruiting branch groups in ’Niitaka’ and ’Housui’is 0.9-1.8cm, while the desirable base diameter of fruiting branch groups in ’Kousui’is 1.2-2. lcm and that in ’Nijisseiki’ is 1.2-2.4cm.