Effect Of Y Series Interstock On Dwarfing And Branching Of Annual Apple Trees And Its Mechanism

Dwarfing and dense planting has become the mainstream direction of Apple Development in the world because of its low consumption,high yield,easy management and advanced technology.In this experiment,Y-1,Y-2 and Y-3 interstocks selected by Pomology of Shanxi Academy of Agr icultural Sciences were used as materials,and SH1 interstocks were used as reference,to investigate the effects of different interstocks on the growth,branch composition,endogenous hormones in leaves,carbon and nitrogen nutrient distribution of annual young trees of ‘Fuji Nagafu No.2'.The growth,endogenous hormones and nutrient elements distribution of ‘Fuji Nagafu No.2' trees grafted with different interstocks were studied.The regular ity of element distribution provides a theoretical basis for the future popularization and application.The main results are as follows: 1.The effects of different intertocks on the height,new growth and branching characteristics of `Fuji Nagafu No.2' young trees were signif icantly different.The dwarfing effects of different interstock on `Fuji Nagafu No.2' were as follows: Y-2 >Y-1 > SH1 >Y-3;the length of shoots was Y-3 > SH1 > Y-1 > Y-2;the ratio of rootstock diameter was SH1 > Y-1 > Y-2 > Y-3;the length of internodes was Y-3 > SH1 > Y-1 > Y-2;the branching ability was Y-2 > Y-1 > Y-3.The Dwarfing Effect and branching ability of Y-1 and Y-2 interstocks on `Fuji Nagafu No.2' were better than those of SH1 and Y-3.2.The contents of endogenous hormones and their ratios in young leaves of different interstocks `Fuji Nagafu No.2' were different.IAA content in top leaves was negatively correlated with plant height and positively correlated with branch number,while IAA content in middle leaves was inversely correlated with branch number;IAA/ABA ratio in top leaves was positively correlated with branch number and negatively correlated with dwarfing effect,IAA/ABA ratio in middle leaves was inversely correlated with branch number and was negatively correlated with dwarfing.The results were positively correlated,but the ratio of(IAA+GA3+ZR)/ABA was not signif icantly correlated with plant growth potential and number of branches in both periods.The high level of IAA/ZR expression in top leaves of main trunk was positively correlated with the number of branches in young apple trees,and the low level of IAA/ZR expression in middle leaves was beneficial to the germination of lateral buds and the growth of lateral branches.3 The total soluble sugar,protein content and C/N ratio of young leaves on different interstocks `Fuji Nagafu No.2' were negatively correlated with plant height,positively correlated with the number of branches,while starch content was not significantly correlated with plant height and number of branches.The high C/N ratio is beneficial to the formation of plant branching.4 Different intermediate rootstocks have different effects on the mineral element content of young leaves of `Fuji Nagafu No.2'.Y-1 and Y-2 interstocks have some hindrance on the absorption and transportation of K and Mg mineral elements,and the absorption of Fe and Zn by Y combination is lower than that by SH1 combination,Y system should pay attention to the application of Fe fertilizer in production.