Effects of 10 Dwarfing Interstocks on Cold Resistance of ‘Tianhong 2’ Apple

The lack of dwarf stock with good cold resistance has affected the production of apples in northern China. Annual dormant branches of ‘Tianhong 2’ apple were grafted on 10 different dwarf interstocks (the rootstocks were the seedlings of Malus hupehensis var. Pingyiensis) as test materials. Among these 10 interstocks, Huang 6, 244, NO.1, 53, 24-5, ZC9-3, Jizhen 1 were newly developed by us (Apple Research Group of Hebei Agricultural University), and three interstocks with different degrees of cold resistance (GM256–with strongest cold resistance, SH40–with stronger cold resistance, M9–with poor cold resistance) were used as controls. The semi-lethal temperature (LT50) and related physiological indexes of the branches in the overwintering process were studied. Based on the comprehensive physiological indexes, the effects of 10 interstocks on cold resistance of the ‘Tianhong 2’ apple were analyzed. The results showed that the effects of 10 kinds of interstocks on the cold resistance of ‘Tianhong 2’ apple were quite different. The order of effects on cold resistance from strong to weak was as follow: GM256 > Huang 6 > 244 >NO.1> 53 > 24-5 > ZC9-3 >Jizhen 1 > SH40 > M9. The purpose of this study was to screen out the interstocks with strong cold resistance, in order to provide some basis for the selection and utilization of interstocks with strong cold resistance in apple cultivation to further promote the development of the apple industry in China.