Study On Adaptability Of Different Scion-stock Combinations Of Pear

Dwarfing rootstock cultivation on pear could induce promoting dwarfing of grafted trees,early maturity,high yield and high quality fruit.However,the different scion-stock combinations would lead to the change scion traits,thus influencing the growth,fruit qulity and yield of those pear trees,finally having a direct impact on the economic benefits.The scion-stock combinations with the‘Pyrus betulifolia'as a rootstock and‘Qing Ai'as interstock,as well as the scion-stock combinations with the‘Cydonia oblonga'as rootstock and‘Hardy'as interstock was used in this research.Based on the previous research of adaptability on scion-stock combinations of pear,the difference in tree growth vigor,grafting affinity,fruit quality and yield of the-6-year old scion-stock combinations were compared,which provided a theoretical foundation for selecting suitable scion-stock combinations of pear.The major research results are as follows:1.Using‘Pyrus betulifolia'as the rootstock,‘Qing Ai'as the interstock,the scions are‘Hongxiangsu',‘Yu Luxiang',‘2-49',‘Dangshansuli'and‘AgrabbéFetel'et al.All trees showed good grafting compatibility and can flower and fruit normally.When selecting‘Qing Ai 1'as the interstock,the ratio of the cultivar/interstock's check the expression would be 0.74-0.90.When‘Qing Ai 3'was used as the interstock,the ratio of the cultivar/interstock's trunk length to circumference would be 0.83-1.01.As the interstock and cultivar,‘Qing Ai 3'has better compatibility than‘Qing Ai 1'.The proportion of stockscion's with different length of one year branches was consistent,it's mainly medium and short branches,long branches have the smallest proportion.As the interstock,‘Qing Ai 1'has better dwarf effect than that in‘Qing Ai 3',but‘Qing Ai 3'caused better fruit quality than‘Qing Ai 1'.Comparing with 2017,‘Qing Ai 3'as the interstock,the yields of the four cultivar of‘Hongxiangsu',‘Yuluxiang',‘2-49'and‘Dangshansu'reduced by half effected by the extreme weather in 2018.However,as the interstock,,‘Qing Ai 1'were not affected by extreme weather,and all the scion-stock combinations'yield has increased.2.The scion-stock combinations with‘Cydonia oblonga'as the rootstock and‘Hardy'as the interstock were chosen to graft several kinds of scion varieties(‘AgrabbéFetel',‘Hongzaosu',‘2-49',‘Zaosu',‘9712'and‘Starkrimson'),the ratio of the interstock to rootstock was 0.86-1.09.Although scion-stock combinations showed inconsistent growth trends,there is no effect on the growth,and all of them can bloom and bear fruit normally.The height of the tree was from 2.95 m to 4.12 m.Moreover,the pear trees were dwarfed.The compositions of the scion-stock combinations branches are consistent.The main branches are medium and short,short branches accounts shared the highest percentage,middle branches and long branches are followed.The fruit quality of all varieties combined with the rootstock of‘Cydonia oblonga'was better,and the yield was not affected by the extreme weather in spring 2018 and maintained stable growth.When using‘Starkrimson'and‘AbbéFetel'as scions,the average annual yield of 6 years old scion-stock combinations were 6207.90 Kg/667m~2 and 4000.44 Kg/667m~2,respectively.