Study On Tissue Culture Of Peach Cultivars And Callus Induction From Their Leaves

The stable, efficient plant regeneration system is the prerequisite to success for transformation with Agrobacterium tumefaciens. In this study, different cultivars of peach, 'Beijing27', 'Baifeng' and 'Dajiubao' which are mainly cultivated in the most areas of China were used as materials for the establishment of explants and for inducing callus of the in vitro leaves. Sterile system were established when adopting the shoot-tips of winter resting buds and the stems and terminal buds in the growing season. By means of the orthogonal experiment design, analysis of variance and multiple comparisons, it indicated that the best times for choosing materials and the best sections for choosing materials, the best combination of plant growth regulator for proliferation of in vitro shoots, the controlling of vitrification, and the controlling of endopyhtic bacteria by antibiotics on the in vitro cultured explantlets, we are also studied the emphasis on the effects of genotype, basic media and plant growth regulator on the callus induction of the in vitro leaves of peach cultivars 'Baifeng' and 'Dajiubao'. The results were as follows:Firstly, through the analysis on the explant's rate of pollution, rate of death and rate of browning , the best times for choosing these three different cultivars' stem and stem apex is April or May, the best sections is the stem apex of active buds.Secondly, though the analysis on the proliferous index, numbers of differentiation buds and unfurling leaves per shoot, the optimal initiation media for shoot proliferation of each cultivar was respectively as follows: for 'Beijing27'and 'Baifeng', shoot proliferated best on MS supplemented with BA1.0mg/L , IBA0.1 mg/L and GA₃1.0 mg/L;for 'Dajiubao', shoot proliferated best on WPM medium containing BA1.5 mg/L plus 0.1 IBA mg/L and GA₃2.0 mg/LThirdly, through the analysis on the effects on the controlling of vitrification of the in vitro shoots of peach in terms of the B A concentrations, the sucrose concentrations, adding BAO.5-2.0 mg/L, Sucrose30⁴0g/L and Agar6.0⁸.0 mg/L up to the optimal initiation medium were beneficial for the controlling of vitrification of the in vitro shoots of peach.Fourthly, effects of cefotaxime and carbenicillin concentrations on the controlling of pollution of the in vitro shoots of peach showed that 100-200 mg/L antibiotics can effectively hold back the endopyhtic bacteria of the in vitro shoots of peach and can't inhibit the growth obviously; 150 mg/L cefotaxime inhibit entirely the endopyhtic bacteria on 'Baifeng' and 'Dajiubao', while 200 mg/L carbenicillin inhibit entirely it on that of 'Beijing27'.At last, through the analysis on rate of callus and necrotic leaf discs from the in vitro leaves of 'Baifeng' and 'Dajiubao' and the quality of their callus, the optimal initiation medium for these two cultivars' callus induction are as following respectively: for 'Baifeng', callus induced best on 1/2MS supplemented with TDZ1.5 mg/L and NAA0.1 mg/L. For 'Dajiubao', callus induced best on WPM medium containing TDZ1.0 mg/L plus IBA0.4 mg/L.