Effects Of Planting Date And Branch Management On Growth Characteristics Of The Young Apple Tree

In the loess plateau of our country, due to lack of rainfall, young trees grew slowly. Thetraditional young apple tree management preferred to remove the branches before bud burst.The main trunk were stonger, The trees were bigger. Europe and other countries used feathernurseries to build orchard. With retaining the branches and branches management techniques,the orchord could get production in the first year. Because of special climate type andcomplex soil conditions in China’s apple production area, the nursery tree should be planted atproper time and using good methods according to apple species characteristics and the localclimate characteristics. To ensure the survival rate of seedlings and reduce the low growthperiod, We can not copy the foreign apple nursery methods and the new established orchardmanagement techniques. This research focused on the effect of branch retaining and pruningon the tree grow and carbon and nitrogen allocation.The objective of the first experiment was to study the growth characteristics of thedifferent types of nursery at different planting dates. We chosen3-year-old apple tree（Malusdomestica Borth.）cultivar Fuji Nagafu No.2as material, we used two factors completelyrandom block: planting date: March10; April10, and May10in2010, nursery type: branchedtree, branch pruning tree (the branches of branched tree cut off from the junction with thetrunk when planted) and unbranched tree, including nine treatments. We investigated thesurvival rate and low growth rate after planting, the dynamics of height, shoots and trunkdiameter, the characteristics of branches and leaves in the first year after planting, canopycharacteristics in the second year and flower numbers in the third year. The results showedthat: the survival rate of all treatments were greater than95%. Both planting date and nurserytype had significant effects on growth potential. The trees planted in May showed low growpotential, compared with trees planted in March and April. The proportion of the low growthpotential unbranched trees was the highest. Two years after planting, the height, trunkdiameter and shoots length of the tree planted in March and April were significantly higherthan those planted in May. The height of branches pruning trees and unbranched trees had nodifferences, but both significantly higher than branched trees. The diameter of the branchedtree was the largest. And the unbranched tree was smallest. The differences of the diameter of the three nursery types were significant. The canopy width of branched trees and branchespruning trees were larger than unbranched trees. The number of second order branches ofbranched trees was the most and significantly more than branches pruning trees andunbranched tree. The flower numbers of branched trees in the third year were significantlymore than the branches pruning trees and unbranched trees. According to the experimentresults, we concluded that after winter cold storage, the suitable planting date of branched treein the Guanzhong area was in early March. The branched trees were conducive to gettingearly fruiting.We chosen3-year-old apple tree（Malus domestica Borth.）cultivar Fuji Nagafu No.2asmaterial to study the effect of pruning branches on young apple trees. We investigated, thedynamics of shoots and trunk circumstance, leaf character, dry weight and nitrogenconcentration of each organ,15NUE, and13C distribution. The result showed that the shootslength of branch pruning trees were significantly longer than control, but their trunkcircumstance were smaller. the aboveground dry weight were no difference between branchpruning trees and the control. The belowground dry weight of of the branch pruning treeswere significantly smaller than that of the control. The leaf area, leaf thickness, leaf freshweight and dry weight and chlorophyll content in branch pruning were significantly greaterthan that of the control. In the spring fast growing stage, the distribution of pulse labeled13Crate in leaves and shoots were greater than that of the control.74%of the whole plant pulselabeled13C was in the leaves and shoots. Distribution of13C in coarse roots and fine rootwas significantly smaller than that of the control. Throughout the growing season, totalsoluble sugar concentration of branch pruning tree’s shoots was greater than that of thecontrol. Two months after pruning the branch, the trunk phloem’s soluble sugar concentrationand the total sugar concentration of the control were significantly greater than that of thebranch pruning tree. one months after pruning the branch, Branch pruning tree’s shoots andtrunk phloem nitrogen concentration were significantly greater than that of the control, butquickly lower than the control. In the early time after pruning the branch, nitrogen useefficiency of branch pruning tree was significantly lower than the control. At the end of thegrowing season, the plants were able to restore the aboveground biomass. After pruning thebranches, carbohydrates of the new assimilation was mainly transported to the growing leavesand shoots, not for storage. Phloem is the main storage organ, which supplied carbon for theshoots and leaves. After pruning, nitrogen use efficiency reduced. The new absorbed15N isprior to transport to the shoots and leaves.