Effect Of Pruning Measures And Growth Regulators On The Development And Potential Of Result Of Carya Illinoensis

Pecan(Carya illinoensis)loved by consumers is the world's famous high-grade nuts,edible oils,wood and garden tree species.It has high economic value and it's market prospect is broad.Our country had introduced pecan since the beginning of the nineteenth century,but we always used extensive management a long time resulted in the result late and low yields.It severely limited industrial development of pecan.The apical dominance of pecan was obvious.It's vegetative shoot elongation growth dominant and lower lateral bud germination rate was low resulted in the baldness of lower of vegetative branches.Only when it reached a certain length,the apical dominance lost due to natural droop.Then bud of department of vegetative branches germinated to short branch and thus terminal bud on the short branch formation the female flower bud.To shorten the start time of pecan result,control flourishing,promoted nutrient accumulation and differentiation,improved the number of fruiting branches,so the pecan flowered earlier.The study conducted the following studies:through different pruning intensity?girdling and ringing of branch and trunk,combining with the survey of morphology of fruiting branches,researched the effect of these pruning methods on the growth and development of pecan and select appropriate pruning methods.On the other hand,through different concentrations of DA-6,PBO,6-BA foliar spraying and paclobutrazol(PP333)root irrigation,studied the effect of these growth regulators on the growth and development of pecan.Through above systems research,provided technical support for the industrial development of pecan.The main results were as follows:1.Morphological survey of fruiting branches of C.illinoensisThrough the morphological survey of fruiting branches of three varieties 'Mahan'?'Western' and 'Jinhua',we found that the fruiting branches length of these varieties were between 0-30cm,where the fruiting branches of 'Mahan' were mainly between 0-10cm,'Weston'concentrated between 10-3Ocm,'Jinhua'concentrated between 0-20cm.The fruiting branches of three varieties had basically only one terminal bud which could develop into flower.Each female inflorescence average had five female flowers and the angle of fruiting branches were between 20°-60°.2.Effect of different short-cutting intensity on the growth and development of C.illinoensisThrough different short-cutting intensity(CK,1/4stub,1/3stub,1/2stub)on the new branches of two pecan varieties 'Mahan' and 'Western',we found that short-cutting could increase the germination rate,promote new branch elongation and thickening growth.The germination rate after 1/2 heavy short-cutting was significantly higher than other treatments and the number of new branches of light short-cutting(1/4stub,1/3 stub)were more than heavy short-cutting(1/2 stub).Meanwhile short-cutting increased the chlorophyll content and specific leaf weigh of two varieties and enhanced photosynthetic capacity and C/N of branches and leaves.For pecan varieties 'Mahan' and 'Westerm',1/3 short-cutting may produce more fruiting branches and would not form too many flourishing branches.This indicated that 1/3 short-cutting was important to the formation of fruiting branches and prematurity.3.Effect of girdling and ringing on the growth of C.illinoensisThrough girding and ringing of trunk and main branch,we found that they all increased the germination rate,enhanced the roughness of branches,reduced the length of branches and promoted the formation of stubby branches.Meanwhile they all improved soluble sugars,starch content and C/N of branch and leaf.Girdling of trunk and branch was most significant.Therefore,modest girdling of branch and trunk could promote the formation of fruiting branches of 'Mahan',but it must be carried out in strong trees and branches and need to strengthen the management of fertilizer and pest control after short-cutting.4.Effect of foliar application of growth regulators on the growth of C.illinoensisDA-6 and 6-BA both could promote branch elongation and thickening,enhance the photosynthetic capacity and nutrient accumulation in leaves.They could rapidly expand its crown,promote vegetative growth for pecan saplings.Considering the growth of pecan and production costs,the effect of 25 mg·L-1DA-6 and 50mg·L-16-BA were most significant.PBO promote the formation of stubby branches,enhance photosynthetic capacity and nutrient accumulation and fruiting branches of pecan mostly were stubby branches,so PBO had a very good results to inhibit vegetative growth and promote early fruit yield.The effect of 150mg·L-1PBO was most significant.5.The effect of PP33 on the growth of C.illinoensisPP333 root irrigation shorten the length and internodes of fruiting branches,greatly increased the number of new branches and fruiting branches,promote differentiation,increased the fruit yield.So PP333 had a significant effect to inhibit flourishing and promote early flowering.