Studies On Polyploid Grapevine Induction By Colchicine Treatment Through Tissue Culture

Grapevine is a major traditional fruit tree in the world. It is a significant way to induce tetraploid to breed new grapevine varieties of high production and top quality. We researched on tetraploid grapevine induction by colchicine treatment through tissue culture.The results of induced calluses had been obtained as follows: the frequency of callus induction was much high in MS or B5 with different concentration of 2,4-D, 6-BA and colchicine; the appearance and characteristics of induced calluses were closely related to type of explants, media and colchicine.Observed the chromosome of induced pellet differentiated competence calluses, it was found that the wide-ranging chromosome variation existed in pellet calluses induced by different media with colchicine or absence of ones. Except for normal 2n=38 diploid cells and 2n=4x=76 tetraploid cells, aneuploid cells was found in calluses. The difference of chromosome variation was related to different grapevine varieties and media. The higher 4x cells rate calluses had been obtained in B5 medium with colchicine 20mg/l, 2,4-D 1.0mg/L and 6-BA 0.5mg/L. Red globe was easier than Jingxiu and Exotic in inducing double chromosome calluses . Regenerated plants had not been obtained through inducing calluses in MS and B5 media. It was maybe related to the chromosome variation of calluses. The higher the chromosome frequency variated , the lower the callus differention frequency was.The tests of tetraploid induction in micro propagated buds was done through daubing axillary buds with grease colchicine, immersing ones in colchicine solution, covering ones with colchicine absorbent cotton, and inducing ones on media with colchicine. The results showed that the last three methods was more effective in inducing tetraploid than the first one. But the seedling rate, mutation rate, induction frequency of treated materials was obviously different.As far as plants induced by immersing axillary buds were concerned, seedling rate was up to 15,1%, aberrant buds rate 4.1%, 4x cells rate 31.8%; seedling rate 54.2%, aberrant buds rate 5.9%, 4x cells rate 30.3% for ones induced by covering buds; seedling rate is 19.0%, aberrant buds rate 9.0%, 4x cells rate 53.3%, and its rang of change 30.3%-66.1% for ones induced by media with colchicine.Induction effect through media with colchicine was inferior to that through covering axillary buds in seedling rate, but it was better in induction frequency and 4x cells rate of induced plant. To obtaining higher 4x cell rate of induced plant, the optimal way was to induce axillary buds on MS with colchicine 20mg/L and 6-BA 0.01mg/L for 2 weeks. The effect of induction was related to different varieties. The sports whose 4x cells rate were up to 50% had not been obtained by inducing Jingxiu and Exotic. The two induced plant H120-1 and H120-3 whose 4x cells rate was 66.1%, 64.6% respectively had been obtained by inducing diploid Red globe through media with colchicine.The results of observing chromosomes variation in 3 progenies showed that the ploidy of H120-3 was stable. Compared with maternal plant, the lines exhibited typical polyploidy characteristics: leaf largen, stalk bulkyen, top and axillary bud fullen plump, growth strongen, and its propagation multiple obviously increased. The elite lines were being appraised for further selection through cutting axillary buds.