Study On Resistance Variation Of Populus Deltoides To Tetra Lobulifera (Keifer)

The paper studied the damage characteristics of Tetra lobulifera (Keifer) and the resistance variation of 18 clones of Populus deltoides to Tetra lobulifera. (102-14, 104-2, 40-1, 66-9, 74-4, 81-16, 81-22, 86-10, 86-14, 86-2, 86-3, 86-8, 89-2, 89-3, 89-7, 94-30, 95-44, 96-10) Their mechamisms were also studied.1,Both nymphs and adults of Tetra lobulifera (Keifer) affect trees, which mainly attack young seedlings and top of young poplar trees. They use their mouthparts piercing and sucking sap from leaf tissues or shoots, damaging conducting tissues of leaf and shoot, resulting shrink, distortion and the falling of leaves, in its acute forms, causing defoliation even death. It severely affects the growth and quality of young poplar plants.2,Significant difference of resistance in certain clones of Populus deltoides to Tetra lobulifera existed. Using the index of leaf injury as resistance appraisal standard, the results indicated that 81-16, 86-3, 74-4, 86-8 clones are resistant clones and 86-10, 81-22, 104-2, 94-30 clones are susceptive clones.3,Variance analysis indicate that differences in all characters of 18 clones of Populus deltoids at seedling stage (one-year-old cuttings and two-year-old root system and one-year-old stem) are significant at 0.05 level or 0.01 level except for height, the height of trunk, lateral branch height, lateral branch diameter of one-year-old cuttings.4,The correlation analysis of 11 characetrs of 18 clones of Populus deltoids at seedling stage were studied. The results showed that there were significant positive correlations between lateral branch height, lateral branch length, lateral branch diameter, number of lateral branches, biomass of lateral branches and the index of leaf injury of one-year-old cuttings, with the correlation coefficient of 0.5050, 0.4874, 0.5992, 0.4557 and 0.4300 respectively. There were significant positive correlations between lateral branch length, lateral branch diameter, biomass of lateral branches and the index of leaf injury of two-year-old root system and one-year-old stem, with the correlation coefficient of 0.6046, 0.7041 and 0.4580 respectively. There are close correlations between branches relative traits (such as biomass of lateral branches) and infestation. So that infestation was related to plant type at seedling stage.5,The relationship between the content of main chemical substances in leaves of 18 certain clones of Populus deltoids and resistance to Tetra lobulifera (Keifer) was studied. The results showed that the contents of soluble sugar, protein and total phenolics in leaves of certain clones of Populus deltoids are significant difference. Correlation analysis indicated that the index of leaf injury was not correlated with the content of protein in leaves; while it was extremely negatively correlated with the content of soluble sugar in leaves(r=-0.6937**); and significantly negatively correlated with total phenolics in leaves(r=-0.5252*).