Mutation Induced By EMS And Its ISSR Analysis In Loquat(Eriobotrya Japonica L.) Dormant Buds

In this research, branches from8-10year-old mother plants of ’Dawuxing’ loquat were used as experiment material to study the effect of EMS on loquat dormant buds. The main purpose of this experiment was to elucidate the suitable time of girdling, the effects of EMS on the mutation of loquat dormant buds. ISSR was used in the analysis of the shoots from the dormant buds induced by EMS. The results were as follows.1. The branches were girdled in different periods (flower bud differentiation period, flowering period, young fruit period, rapid fruit growth period, fruit maturity period, period after fruit harvest). The results showed that the girdling applied after fruit harvest was the most suitable.As the girdling applied after fruit harvest, the germination time of dormant buds was concentrated, the number of shoots germinated after girdling was large, shoots of dormant buds growed rapidly.2. The dormant buds were subjected to different treatment levels of EMS, and the results of dormant bud germination and growth showed that with EMS concentration increase, there was a decrease in dormant bud germination; with the EMS exposure time increase, the sprouting number of dormant buds declined.151shoots from dormant buds treated by EMS were obtained, and there were16shoots whose phenotype (such as leaf shape, leaf color, etc.) appeared obvious change. The mutagenic effect was the best when dormant buds were treated by0.5%EMS for3days.3.6ISSR primers were selected from100candidate primers and used in ISSR analysis of the16morphological variation shoots from dormant buds treated by EMS. The DNA bands of12shoots through ISSR amplification had the very high polymorphism. This high polymorphism indicated that EMS could expand the scope of genetic mutations on loquat dormant buds. 4.6ISSR primers were used in ISSR analysis of the151shoots from dormant buds treated by EMS. The DNA bands of13shoots from dormant buds treated by EMS showed polymorphism, and it indicated that the gene of these13shoots from dormant buds may be changed. EMS could improve gene mutation frequency of loquat dormant buds.