Study On The Pruning Method Of Fruit Set Of Castanea Mollissima ’Zunhuaduanci’

There are many problems in Castanea mollissima Blume orchard such as rough tree management,outward movement of fruit set,weak tree vigor and uneven yield.One of the effective solution is proper pruning and renewal method,which can rationally distribute nutrition of the tree so as to improve the quality and yield of the fruits in different degrees.In this experiment,the growth and fruiting ability of shoots with different growth vigor were studied under different pruning intensities.The annual growth branches and bearing branches of Chestnut’Zunhuaduanci’ were selected from Weijinhe Forest Farm,Zunhua City,Hebei Province.According to the basal diameter,the branches were divided into three types:weak branch(basal diameter<6mm),middle branch(6mm<basal diameter<7.5mm),strong branch(basal diameter<7.5mm).Three types of branches are heavily/moderately/slightly pruned or no treatment.The responses of different parent branches to different truncation strengths were studied.The results are as follows:1.The base diameter of the new shoot of weak bearing branch was more than 6 mm after the extremely heavy pruned.The number of fruit of mother branches after no treatment was up to 2.12,which could be used to bear fruit in the same year and could not bear fruit continuously.So weak fruit branches should be no treatment or removed.The base diameters of new shoots of middle branches were 6.51 mm and 7.63 mm respectively after the heavily pruning and extremely heavy pruning,and 2.57/mother branch after moderately pruning,and the base diameters of new shoots were more than 6 mm.For the moderately bearing branch,heavy pruning and extremely heavy pruning could be adopted.In order to improve the quality of branches and cultivate them into preparatory branches,continuous fruiting can be achieved through moderately pruned;The number of male inflorescences reached 7.29 per new shoot and the number of fruit was 2.08 per mother branch after the strong bearing branches with extremely heavy pruning,and the base diameter of the new shoot was 7.05 mm.The new shoot could bear continuous fruits and form stable fruit set.Therefore,the bearing branch can be renewed by two branches,the weak bearing branch can be set off,then the current year’s results can be carried out,and the middle bearing branch can be pruned by heavy or extremely heavy pruning to make it produce stronger branches,and then the weak bearing branch that was set off this year can be pruned next year,and two branches are selected from the base of the median bearing branch for renewal.2.The base diameter of the new shoot of the weak developed shoots are all below 6 mm,and should be pruned.After heavy and extremely heavy pruned,the number of shoots will be 2.20/mother branch and 3.80/mother branch,and the base diameters of the new shoots are 7.25 mm and 6.70 mm.The male inflorescences were all above 6 per new shoots when the strong growth branches were truncated arbitrarily,and the diameter of new shoots is over 6 mm,the number of fruit is also more.The effect of heavy and short cutting is the best.The number of blooms is 3.20/mother branch,which is 1.27 more than that no treatment.After heavy pruning,and extremely heavy truncation of middle branch,arbitrary pruning of strong growth branches can not only promote the current year’s fruit setting,but also maintain the quality of branches,and can carry out continuous results,so it can be regenerated single branch.3.After pruning,the number of male inflorescences with new shoots on stronger bearing branches was more than that on growth branches,and the number of blooms was less than that growth branches.That is to say,pruning could promote the germination of male inflorescences of bearing branches and the development of mixed inflorescences of growth branches.4.Through pruning,the distance between the new shoot and the main trunk can be shortened,and the outward movement of the fruiting part of chestnut can be efectively prevented.