Study On Establishment Of Rapid Propagation System And Micrografting Of The Pear Cultivar Xinli Pear7

The rapid propagation system in vitro of the pear cultivar Xinli pear7was establishedpreliminary by studying the disinfecting reagents and processing time of implants, mediumof initiating and shoot proliferation culture, and induction of adventitious roots. Futher, themicrografting in vitro protocol was suggested by using the subculture seedlings of Xinlipear7and Pyrus betulaefolia as scion and rootstock, respectively. The grafted plants hadbeen obtained. The main results are as follows:1. One-year-old shoots were collected from the field in the early spring and taken tothe lab, washed with DI water, inserted the shoot basal parts into water, and cultured at thecondition of temperature at25±2℃with natural light. When the third new leaf unfoldedafter bud break, the new young shoots were cut as explants for the preliminary inoculation.The survival rate could reach as high as100%, and the browning rate and contaminationrate were very low.Treating the explants from the field with disinfectors5%NaClO：0.1%HgCl2=1：1for7min,and washing them with sterile water for5times, could reach a survival rate at77.78%.2. The medium of1/2MS+6-BA0.75mg/L+NAA0.05mg/L+sucrose35g/L wassuitable for initiating culture with the proliferation rate at5.59.3. The1/2MS as basic culture medium was advantageous to the bud differentiation ofXinli pear7, while the MS promoted the growth of the differentiated buds. The supplementof6-BA2.0mg/L+NAA0.05mg/L+sucrose35g/L into both of the two media and usedalternatively, was suited for the subculture and multiplication.4. Shoots longer than1.5cm could be used for rooting. When inoculated on medium1/2MS+IBA2.5mg/L+sucrose20g/L and dark cultured for a week prior to normalphotoperiod, the rooting rate could reach75%after30d.5. The micrografting in vitro protocol was tested by using Xinli pear7seedlings onsubculture as the scion and Pyrus betulaefolia seedlings as stock. The cleft grafting methodwas adopted. Foil paper was used as fix material. The survival rate of graft materials couldreach75%, and the rooting rate could reach56%.