Study On The Applied Effect Of The S₂, S₅ And PDR₅₄ Dwarfing Inter-stocks Of Pear

With S2, S5 and PDR54 dwarfing inter-stocks grafted different varieties as plant materials , the applied effect of the grafting pear, including its disease resistance, dwarfing performance , mineral elements content, early bearing ,high yield, fruit character and plant-test benefit etc ,was investigated in this paper. The main advances were as follows:1. There were dwarfing effects of three dwarfing inter-stocks S2, S5 and PDR54 on cultivar when they were grafted different cultivars. The order of dwarfing intensity was PDR54 > S5 > S2.2. There were accumulated dwarfing effects of dwarfing inter-stocks in three different length on grafting cultivars, and with the increasing of the length of dwarfing inter-stocks, the five items about dwarfing effects become declined on different degree. The length of dwarfing inter-stocks affected the dwarfing effect. The length was longer, and the dwarfing effect was stronger. On the contrary, the dwarfing effect was smaller. The inter-stocks had significant dwarfing effect, but when the length of inter-stocks was 10cm,the dwarfing intensity was strongest. The treatments of 5cm,20cm dwarfed more litter than 10cm treatment. The other dwarfing items ware same trend, and the rule was distinct.3. The inter-stocks had also sensitive effects on the different cultivars. In four treatments of Zaosu, Yali, Xuehua, Jinfeng, the Yali treatment had the most sensitive effect on dwarfing inter-stock ,and the Jinfeng treatment was the most least.4. Other mineral elements variably changed in the range of 10% in the leaves of Zaosu pear using S2 and S5 as inter rootstock, but Fe and N exhibited a consistently upward trend .In the leaves of pear using inter-rootstock PDR54, mineral elements contents (N, P ,K, Ca, Mg, Fe ,Zn) which weremeasured in the experiment showed a downward trend and Ca and K. dropped above 10%.5. Compared with the control, pear (Zaosu, Jinfeng and Xuehua) with S2, S5 and PDR54 as inter rootstock bore fruits ahead of 2-3 years .Pear with PDR54 fruited even more early. The efficiency of fruiting yield of pear with inter-rootstock S2, S5, PDR54 was 1.23, 1.24, 1.48 times that of arbor-rootstock pear ,respectively.6. There was a decreasing trend towards the fruit volume and total acid in 'Zaoshu pear' using different dwarfing rootstocks, while the contents of Vitamin C ,sugar and soluble solids rose .In addition, it was superior to the control in fruit flavor, quality and its market.