Selection And Breeding Of Dwarf Mutant Of Cherry Semi-dwarf Rootstock Variety-Mahaleb ’CDR-1’

The cherrry is the earliest and most profitable fruit in the northern deciduous fruit trees.Rootstock is the basis of the development of fruit trees,and the resistance of rootstock is directly related to the success of sweet cherry cultivation.Among them,cherry rootstock ’cdr-1’ is suitable for cultivation and promotion in northern China due to its strong resistance to root cancer,strong adaptability,cold resistance,drought resistance,salt-alkali resistance and barren resistance.As an excellent semi-dwarf stock,its dwarfing potential remains to be further explored.In this study,group S of 539 seedlings with high plant height,few branches and dense internode length were selected from 800,000 seedlings of cdr-1 in 2017.The plant height,stem thickness at the bottom and top,and internode length of 20 buds were measured for these 539 plants.After statistical analysis,30 plants were selected for spring bud grafting.In the spring of 2018,each of the 30 selected plants will be grafted with 3-5 buds.During the vigorous growth period of the plants in May,the hormone content and enzyme activity closely related to dwarfing will be determined in the leaves.In November,we also measured the above four data of grafted seedlings,and compared them with CK of the control group and SS of the superior line selected in 2016.We further screened out 13 strains of grafted S’s group,and drew the following conclusions:(1)The difference in plant height between the four groups of cherry reached a significant level,with the SS group being the highest in the three-year group and the next in the control group.The 13 elite lines of the first selection were the shortest;the relative sharpness reached a significant level,and the CK group was the highest.The S’ and S groups were relatively low,and the SS group was the lowest;the internode length reached a significant difference level,with the SS group being the shortest,the S’ and S groups being the second,and the annual control group being the longest;(2)The contents of IAA,GA,CTK and ABA in cherry leaves and the ratios of GA /ABA,IAA /ABA and IAA+GA+CTK/ABA were significantly different in different types.The content of IAA and GA and the ratio of GA/ABA,IAA/ABA and IAA+GA+CTK/ABA were negatively correlated with the degree of tree dwarfing.The content of CTK was negatively correlated with the degree of tree dwarfing.In contrast to growth promoting hormone,ABA content was positively correlated with tree dwarfing degree.