The Resisttance of Poplar Varieties to Melamposora Larici-Populina Kleb

Melampsora larici-populina Kleb, is also called populus cathayana leaf rust, is a fungi transferred its host and widely distributes in various poplar planting areas in the world, which do harm to Tacamabaca, Aigeros, and their hybrids. It is a kind of poplar disease, which disserves furthest, mainly distributes in northeast, northwest, North China and the southwest in China.In this paper, the state of an illness of Melampsora larici-populina Kleb. on 26 poplar species(it is belong to Populus‘Popularis’、Populus deltoides×P.cathayana、Populus deltoides、Populus deltoides×P.cathayana.)introduced were investigated in field, and the relationship between various poplar species and resistances of poplars to the leaf rust, and the leaf rust happenning and environment factor were analyseed. After the reciprocity of host poplars and Melampsora larici-populina Kleb., the relation between correlation enzyme activity and resistances were staddied with artificial vaccinal method. The main conclusions as following:1. All of the 26 poplar varieties , there were 25 varieties were infested by Melampsora larici-populina Kleb. except Populus deltoides cl‘01’, and he pathogenic indices were 4.21 to 62.67. There was a significant difference in the pathogenic indices of different poplar species or poplar varieties.2. There was a difference of illness state in the 4 hybrid matches, Populus‘Popularis’〉Populus deltoides×P.cathayana〉Populus deltoides〉Populus deltoides×P.cathayana.3. In the same hybrid match, the resistances of the most varieties were different obviously. Therefore, in the work of selecting disease-resistant poplar species, the differences of resistances in poplar species or varieties should be regarded much more than the differences in hybrid matches.4. After inoculating Melampsora larici-populina Kleb, activity of the PAL, POD, PPO , chitinase,β-N-acetyl-D-glucosaminidase in the 6 poplar species or varieties were increased notable. The activity of POD was negative correlative with resistances of the poplar to Melampsora larici-populina Kled., and the others 4 enzymes activity wae positive correlative with the resistances.5. The testing results of these enzymes showed that the activity of POD,PAL and chitinase was observably higher than other enzymes, so POD,PAL and chitinase could been used for physiological index of poplar resistance to the leaf rust.