Study On Induction Of Tetraploid Grapes

Inductions of tetraploid grapes were conducted with colchicine from in vitro Vitis.vinifera cv. 'Jingxiu', 'Red Globe', 'Jingzaojing', 'Rizamat', 'Manicure Finger', 'Red Cocoon', and 'Yatati Rosa'. Ploidy levels were determined by flow cytometry. To explore the effective methods and optimal treatments of induction tetraploids, comparisons of soaking shoot segments in colchicine solution and adding colchicine in the culture medium were done with 'Jingxiu' alone. The effects of both duration of soaking and concentration of colchicine on efficiency of induction were studied. Then, tetraploid grapes were further induced from 'Jingxiu' and 'Red Globe' with an optimal treatment. Finally, five cultivars, including 'Jingzaojing', 'Rizamat', 'Manicure Finger', 'Red Cocoon', and ' Yatomi Rosa', were induced tetraploids. Main results are as follows:1. The soaked-treatment had increased efficiency of inducing tetraploids than one of adding in medium. It was characterized as simple operation, less colchicine usage and effective induction of both pure tetraploids and chimera due to cellular infiltration easily by soaking. On the contrary, the treatment of adding colchicines in the culture medium with different ages of in vitro 'Jingxiu' was poor effect of induction of tetraploids.2. The effects of colchicine on inhibiting plant growth differed in concentration of colchicine and duration of soaking stem fragments in colchicine solution. The inhibition of plantlets growth was enhanced with soaked time extension and the concentration increase. Death of plantlets was observed when the concentration of colchicines was higher than 2000 mg.L^-1 or the duration of soaking was longer than 48 hours. The incidence of death of plantlets mostly was higher than 30% when the concentration was higher than 4000 mg.L^-1. The death rate of 'Jingxiu' and 'Red Globe' was more than 70 % as treated at 4000 mg.L^-1 for 4 d.3. Soaking shoot segments with colchicine at 2000 mg.L^-1 for 3 to 4 d or 3000 mg.L^-1, 4000 mg.L^-1 for 2 to 4 d induced pure tetraploids during first regeneration. A desired range of 16.7 % to 23.3 % of tetraploids was obtained by soaking at colchicines concentration of 3000 mg . L^-1 for 3 to 4 days. However, colchicine concentrations of 2000 mg . L^-1 or lower and soaking for 48 h or shorter induced pure tetraploids after two to five regenerations even though tetraploids were not observed during first regeneration.4. Ploidy of plantlet was not changed through growing, but separation of chimera occurred during regeneration. Some morphological features of leaves and roots were obviously changed while chimeras became into pure tetraploids. These changes were strongly related to either the concentration of colchicine or duration of soaked in the colchicine solution.5. The efficiency of induction varied with different cultivars. The optimal treatment combinations for 'Jingxiu' and 'Red Globe' were to soak stem fragments with colchicines concentration of 4000 mg . L(-1) for 3d, with 16.7 % of tetraploids and 3000 mg . L(-1) for 3 d,...