Studies On Method For Identification Of Heat Tolerance Of Tomato And Selection Of Heat Tolerance Germplasm

Tomato (Lycopersicon esculentum Mill. ) is an important vegetable. Both in field and in protection field , it suffered from heat injury , which severely influenced the crop production. To solve this problem, the selection of materials which can tolerate high temperature should be strengthened firstly. In order to find the best method or reliance index of appraising the degree of heat tolerance of tomato, five tomato varieties were treated with high temperature at different developmental stages (i.e. sprout stage, seedling stage, blooming stage ) in this experiment .By studying the physiological and biochemical indexes of tomato under high temperature and calculating the correlativity among these indexes, we look for convenient and reliable indexes to identify heat tolerance of tomato materials.The experimental result shows as follows. There are some difference of heat tolerance among tomato varieties at each growth duration. The tomatoes whose seedlings were treated with high temperature expressed the following tendency of the increase of the permeability of plasma membrane, MDA content, free proline content and SOD activity, the decrease of root activity and changes of chloroplast ultrastructure. After treated with high temperature at both seedling stage and blooming stage, the fruit setting percent of tomato decreased.The permeability of plasma membrane, free proline content and SOD activity may be used as the appraised indexes of tomato heat tolerance at seedling stage. The relation for linear regression between heat tolerance and three indexes are, respectively: y=0.916x1+0.251; y=0.940x2-1.184; y=0.32x3-1.049. The multiple regression equation of the permeability of plasma membrane and free proline content is : y=-0.365x1+0.612x2-0.646. The ternary regression equation of the three indexes is: y=-0.605x1 + 1.157x2-0.282x3-0.360 (xl: the permeability of plasma membrane; x2: free proline content; x3: SOD activity). There is significant positive correlation between blooming stage and seedling stage of tomato on heat tolerance. So the tolerant materials should be selected at seedling stage.Three materials which can tolerate high temperature are selected in this experiment: 01568,01206 and 01217.Postgraduate: Wang Dongmei Major: Olericulture Supervisor: Prof. Li Jingfu...