| Apple ring rot is one of the three major diseases of apple in China, which caused growth weak of trees, and leaded to numerous rotten fruits before and after harvest. This desease had became the most serious problem of restriction in apple production. In this research, We have made a suggestion about the problem of control of Botryosphaeria canker on apple branch through the results of Investigations on the occurrence of Botryosphaeria canker of apple in Hebei province and the chemical control experiments.The materials for the application of resistant rootstock were provided by researching on rapid micropropagation technique by shoot tip culture of two ring rot-resistant apple rootstock. The main results were as follows:1 During spring and summer in 2014, the occurrence and control status of Botryosphaeria canker of apple were investigated in 66 orchards which located in major apple production areas in Hebei province. The results showed that the incidence of this disease in general was about 76.26%, disease index was 63.70. The occurrence of the disease varied among different regions. Comparatively, the occurrence of the disease was more severe in Tangshan, Xingtai and Shijiazhuang than that in Zhangjiakou and Chengde. The older the tree, the more severe the disease. The incidences and the disease index were 44.71% and 33.55, 100% and 98.53 for the trees at the age of 0-5 and more than 16, respectively. There were significant differences in occurrence of the disease was observed among the main cultivars. Among the chemicals used to prevent Botryosphaeria canker of apple, carbendazim, lime sulphur and tebuconazole were the most popular fungicides.2 The Inhibition effect of six fungicides on Botryosphaeria dothidea was tested by measuring mycelium growth rate, and the curative effects were tested. The result showed that,when the fungicides were applied with recommended dosage by manufacturers,the inhibitive efficiency of the six fungicides were more than 90%, bordeaux paste,tebuconazole and healing agent had the best inhibition to the growth of Botryosphaeria dothidea, the inhibitive efficiency of the three fungicides were 100%, 100% and 99.71%,respectively, The results of curative effects and inhibition effects on mycelium growth were consistent. The curative effects were better after scraping the lesions, and the curative effects of these fungicides, except thiophanate-methyl, were more than 90%,bordeaux paste, tebuconazole and healing agent had the best control efficiency which were more than 97%.3 Taking the shoot tips of the ring rot resistant apple rootstock 1-1-10-8 as materials,the results showed that the sterilization time of shoot tip using 0.1% Hg Cl2 was10 minutes, and the basic medium was MS supplemented with sugar 35 g/L and agar 6.2g/L, the optimal plant growth regulators of start culture medium that suited multiplication were 6-BA1.0 mg/L+NAA0.05 mg/L. The optimal plant growth regulators in subculture medium were 6-BA1.0mg/L+NAA0.075mg/L, and the coefficient of multiplication were exceeded 12.71 times in every four weeks. The optimal plant growth regulators for rooting were IAA1.0 mg/L+IBA0.6 mg/L, the rooting rates of shoots were 98.06%, the average number of rooting was 7.89. Then the rooted plantlets were transplanted, the survival rates were 92.38%.The results showed that taking the shoot tips of the ring rot resistant apple rootstock J35-8 as materials, the basic medium was MS supplemented with sugar 35 g/L and agar6.2 g/L, the optimal plant growth regulators of start culture medium that suited multiplication were 6-BA1.0 mg/L+NAA0.05 mg/L. The optimal plant growth regulators in subculture medium were 6-BA1.0mg/L+NAA0.05mg/L, and the coefficient of multiplication were exceeded 8.5 times every four weeks. The optimal plant growth regulators for rooting were IAA1.0 mg/L+IBA 0.3 mg/L, the rooting rates of shoots were more than 90%, the average number of rooting was 9.6. Then the rooted plantlets were transplanted, the survival rates were 100%. |
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