品种抗性变异与哪些因素有关?
参考答案:
①新的生理小种的出现;
②寄主生育阶段抗病性变化;
③温湿条件对植物和病原物的影响;
④水、肥等管理条件的影响及育种、突变等。
He wanted to know ()the English party.
A. when will we have
B. when we will have
C. when would we have
D. when we would have
下面哪个属于病毒程序的功能模块?()
A、安全模块
B、引导模块
C、转移模块
D、系统模块