New Germplasm Creation And Grafting Technique For Rootless Plantlets In Diospyros Kaki Thunb.

The Oriental persimmon(Diospyros kaki Thunb.) belongs to the Diospyros genus, Ebenaceae Family. The persimmon genetic resources are abundant in China. Recently, some new PCNA and staminate persimmons have been collected in Dabieshan Mountains. They play an important role in persimmon breeding. Embryos culture can shorten the breeding periods, but the persimmon plantlets in vitro are difficult to be transplanted to the field. In this study, some new germplasms were got in F1 by the hybridization of ’Huashi No. 1’×’Luotiantianshi’and’Huashi No.1’×’Male strain No.3’, and the suitable conditions for transplanting F1 plantlets in vitro to the field were also improved. Especially, we successfully established the technique of making persimmon plantlets in vitro be grafted on rootstocks in the greenhouse. The major results are as follows:1. The hybridization tests showed that, the pollen germination rates of the two experimental materials (’Luotiantianshi’and’Male strain No.3’) were 45.6%, and 32.5%, which reached the normal germination ability. And they also exhibited very strong compatibility with’Huashi No.1’, as the fruit setting rate of the two hybridized combinations was 55% and 61%, the average embryos per fruit were 4.4 and 4.7. We got 515 plantlets through embryo culture, including 232 offspring of’Huashi No.1’×’Luotiantianshi’and 283 offspring of’Huashi No.1’×’Male strain No.3’, germination rates of which were 96.3% and 99.0%.2. In the transplanting test, we chose the method of’closed tube and strong light exercise’ to train plantlets. The plantlets grew well, new leaves coming out, height of plant increasing and survival rate exceeding 95% in the forepart, which were transplanted in the same year autumn, but the final survival rates of’Huashi No.1’×’Luotiantianshi’ and’Huashi No.1’×’Male strain No.3’were only 14.3% and 0.6% through the cold winter; On the other hand, the plantlets transplanted in the next spring can get high survival rate which was over 80%. 3. The grafting technique of persimmon plantlets in vitro was successfully established:we grafted the stem-bud of plantlets in vitro on the roorstocks in the greenhouse using cleft grafting, and got survival grafts. The optimum training time of ’closed tube and strong light exercise’was 1 week; The survival rate using perennial Diospyros lotus L. as rootstocks was higher than the seedling rootstocks; The survival rate could be improved by shading and spraying water to make the temperature decrease; There was no significant difference between using different parts of stem as scion; The survival rate was also high when the plantlet in vitro were grafted on adult trees by the above method.