| Object: We conducted a investigation and identifying on fungal diseases which occurred on the processing tomato in xinjiang, and studied the control method and pathogen toxin on processing tomato Early Blight, in order to provide a theoretical basis for controling the fungal diseases and the nosogenesis of toxin systemically on the processing tomato. Methods: 5 spots were sampled randomly to investigate the fungal diseases on the processing tomato in field. We calculate the incidence of disease and disease index, to identify the primary fungal diseases using morphology and ITS sequence analysis.The extracellular toxin was obtained. The toxin’s biological activity was measured by acupuncturing the detached leaves and restrained the growth of radicle and germ; By selecting culture medium、the conditions which will bring germs,and the use ratio of carbon souurce and nitrogen source to determine optimality factors which toxin would be produced by fungal.By testing correlated physiology and biochemistry values on the processing tomato seedlings which were treated by toxin, to confirm the resistance response and the level of harm when different processing tomatos were restricted by toxin. To identify the resistance of different varieties of processing tomoto and select the effective fungicides to control the processing tomato which blighted early. Results: 1.The field investigation indicated that the diseases occurred widely in processing tomato in north Xinjiang are Early Blight disease, Leaf Mould, Wilt disease, Powdery Mildew and Phytophthora Rot disease. Among them, Early Blight disease took place in a large area, every planting regions happened at different levels, while others happened sporadically. There are no other diseases observed. Through identification, the results showed that the pathogen of Early Blight is Alternaria solani(Ellis et Martin) Jones et Grout., Leaf Mould is Cladosporium fulvum(Cooke) cif. Wilt disease is Fusarium oxysporum(Schl.) F. sp. lycopersici(Sacc.) Snyder et Hansen, Phytophthora Rot disease is Phytophthora capsici Leonian, and the pathogen of Powdery Mildew is Oidium neolycopersici Kiss.2. Tomato Early Blight toxin has some toxic action on processing tomato, which could induce partial leaves lesion, and inhibited seed germination.Through optimizing producing conditions of the alternaria solani toxins, we screened out the PSK nutrient solution was the optimum medium for toxin-producing, 30℃ was the optimum temprature, 7.0 was the optimum PH, lactose was the optimum carbon sourse, and ammonium nitrate was the optimum nitrogen source.3. Under the stress of toxin, tolerant varieties presented a more distinct upward tendency of all protective enzyme activities, accordingly, susceptible varieties have a upward tendency of PPD and PAL, but with a slight rise, POD demonstrate a declining tendency, and SOD showed an upward tendency firstly, soon afterwards, became downgrade. Treated by toxin, leaf relative electrical conductivity and MDA content in tolerant varieties and susceptible varieties were both went upward generally with the time extending, and susceptible varieties showed greater changes.4. The results of disease resistance identification in lab demonstrated that, among 15 Processing Tomato varieties, 11 varieties were resistant with ratio of 73%, and 4 varieties were tolerable with ratio of 27%. 15 Processing Tomato varieties were identified and analysed in the field. The results showed that there were no resistant varieties, and 6 varieties were tolerable with ratio of 40%, 9 varieties were susceptible with ratio of 60%. The screening of fungicides was conducted on Early Blight of processing tomato Indoor toxicity trials showd that cymoxanil mancozeb 72% WP was the most effective fungicide against the pathogen with EC50 of 8.1μg.ml-1, Mancozeb 70% WP, Metalaxyl·mancozeb 58% WP, Difenoconazole 10% WP are as follow, others with a low effect. Field plot trials showed that the control effects of cymoxanil mancozeb 72% WP was the highest, the control efficacy reached to 81.2%, Mancozeb 70% WP, Metalaxyl·mancozeb 58% WP and Difenoconazole 10% WP in turn, with the average control efficacy of 73.1%, 71.0% and 61.0%. Conclusion: 1.The main diseases occurring on processing tomato in the Xinjiang producing area are Early Blight disease, Leaf Mould, Wilt disease, Powdery Mildew and Phytophthora Rot disease.2. Either acupuncturing vitro blade or inhibiting germ and root growth by toxin successfully detected biological activity of toxin. The concentration of toxin can effect seed germination directly, the higher the concentration is, the biger the inhibition rates of seed germination. External factors like variety of mediums, temperature, pH, the C and N source, have a severe impact on toxin production.3. After treatment with toxin, tolerant varieties presented a more distinct upward tendency of protective enzyme activities, while susceptible varieties with a slight change in a short period or present a declining tendency. Both of susceptible varieties and tolerant varieties showed a rising trend in MAD content and electrical conductivity, which indicated that this toxin could induce plant to carry out resistant mechanism and effect permeability of the cell membrane.4. Through a study on control of processing tomato deseases, it makes it clear that none of processing tomato varieties commonly planted in Xinjiang is strongly resistant to early blight, which should appeal to enhance the work of breeding. Mancozeb had a efficient impact on early blight. |
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