Application Of RAPD Markers And Morphology In The Assessment Of Somaclonal Variation Of Ramie (Boehmeria Nivea (L.) Gaud)

Collecting and creating new germplasm resources and enlarging the extension of variation are a significant task in crop breeding research. Ramie(Boehmeria nivea (L) Gaud), one of the most important bast fiber crops, has been cultivated and used in China for a long time. With the improvement of living level of people, fiber quality of ramie needs to be improved and elite cultivars are greatly needed in ramie production. However, traditional breeding is retardative because of lack of various breeding methods and germplasm resources. Tissue culture technique which improved rapidly in latest decades, it serves a new approach for ramie creating new germplasm resources. Especially, great successes have been achieved in other crop breeding by using somaclonal variation, which brings a great future to ramie breeding.The goal of this study is to establish a reliable and an efficient regeneration system at the very beginning. Then carried out molecular level's and morphology's variations to ramie regeneration adult plant, at last carried out a preliminary analysis. The main productions are as follows.1. A rapid regeneration system was established for ramie on shoot tip. Takes the growth vigorous and healthy shoot tip, first uses 75% alcohol to soak 30 sec, and then disinfects 8min with 0.05%HgCl₂, then uses the aseptic water to flush 4-5 times total 15 min. Then takes about 5 mm from these the disinfection shoot tips to put in MS+1.0 mg/L 6-BA solid media to cultivate them. By this way the survived bud seedlings grow vigorously and healthily, then continue the regeneration in this culture media to proliferate them for one month, the bud seedlings will multiply about 6 times.2. The regeneration system of induction and differentiation of the ramie leaf callus was established. Namely first induces callus in an induction culture media (MS+0.5 mg/L TDZ+0.5 mg/L NAA), then takes the callus to differentiation culture media (MS+2.0 mg/L 6-BA+0.5 mg/L GA₃ ) to cultivate about 20 days. Lots of the bud seedlings of dense growth can be differentiated and its differentiation rate can approach to 100% at most.3. The somaclonal variation has some obvious disciplinarians and characteristics in DNA level of ramie. The rate of variation founded showed differences between varieties and the regenerants from shoot tips, more higher than the regenerants from callus on leafs. The more cluture times in two regenerant plants, the higher the rate of variation becomes. In those conditions of culture medium the phytohormone plays the most significant role among culture conditions. It is to say, in the certain scope, with the increasing of hormone TDZ density and the reducing of 6-BA density, its variation frequency increases.4. The somaclonal variation has some obvious disciplinarians and characteristics in morphology of ramie. The regenerants from leafs' callus, after the process of taking root and building up, are transplanted to the pot. After Two months investigating theirs parts of shapes, the contrast between the regenerant seedlings and their parents shows that the regenerant seedlings are easy to die, have a morphological dwarfism, delicate stem and so on. Their leafblade shape, the petiole color and so on have diverse variations.5. By choosing the optimization reaction parameters, unfluctuating RAPD results can be obtained.