The Effect Of Enviroment Situation On Soybean Cyst Nematode Hatch And The Mechanism Of Soybean Resisting Soybean Cyst Nematode

Soybean Cyst Nematode(Heterodera glycines Ichinohe)is one of the most importantplant diseases in soybean output. The most efficient and economic way is to plant resistantcultivars for controlling soybean cyst nematode. The number of cysts on the resistant soybeanroot was larger than the susceptible soybean,s . Soybean cyst nematode was better breededunder neutral situation. With high pH and low pH situation ,the nematode in root and cyst onsurface of root is very little. The diffusate of root is one of the most important factor on egg hatch. The compents of rootdiffusate were affected by the different microecology environment in soil. The differentcomponents of root diffusate had inconsistent effect on egg hatch. The root diffusate ofhefeng25 from continuous soybean field stimulated egg hatch. But the egg hatch wasrestrained by kangxian 4,s in this field. The root diffusate of kangxian 4 stimulated more egghatch than hefeng 25,s from WSW,SWC,CSC, fallow plot except SWS. The egg hatch was not only relation with root diffusate ,but also with microecologyenviroment in soil. The leachate of susceptible cultivars compared with resistant,s stimulatedlarger egg hatch. The most eggs were hatched in soil leachate from WSW field without plantsoybean. The hatch efficiency of leachate of black earth, sand soil and alluvial soil withsusceptible and resistant soybean cultivars is higher than distilled water,s. The leachate ofblack earth compared with sand soil and alluvial soil stimulated most egg hatch. In two rotation systems, soybean rotated with corn was better than it rotated with wheat.The number of cysts in soil was low in SWC rotation system. The enzymes of PAL,POD,PPO activity of kangxian 4 was increased when it wasinvaded by soybean cyst nematode. And the activity was higher than susceptible cultivars.The enzyme activity of kangxian 4 was not higher than that of hefeng 25 before they wereinvaded by nematode. But when kangxian 4 was invaded with nematode ,its enzyme activity VII东北农业大学农学硕士学位论文increased highly than hefeng 25,s. The enzyme activity may be a index as soybean resistsoybean cyst nematode. Soybean cultivars kangxian 4 could not restrain eggs of soybean cyst nematode hatch andresist J2 invading, but it could hold back nematode development in root. When observed withmicroscope, there were brown putrescence around J2 head. This may be one of kangxian 4resistant mechanisms. The soybean cultivars kangxian 4 is the cultivars that can resistnematode development in root but can not resist nematode invading. Master Candidate: Si Zhaosheng Speciality: Plant pathology Supervisor: Professor XuYanli...