Abstract: Effects of environmental factors on powdery mildew in wheat seedling were studied in two wheat varieties(cv.Fu63,hypersensitive to the disease and Qianmai 7,resistance to the disease) from 1998 to 2000 in the greenhouse of SDAU,Taian,China.The main results were as follows:powdery mildew could infect the disease sensitive variety of Fu 63 at 6℃,but it didn't enlarge at 6℃.The suitable tempreture for the infection ranged from 14 to 22℃ and optimum tempreture was 18℃.Powdery mildew could infect Fu 63 at any moisture.Disease infection ratio increased with the enviromental moisture.With the increasing of N application rate,the initial stage and the developing stage of the powdery mildew on hipersentive variety changed shorter and disease infection ratio increased.But the range of infection ratio that changed with N rate was not as much as that with the change of temperature and moisture.Under low and middium N level conditions,the infection ratio did not change almostly.The initial stage and the developing stage of the powdery mildew on hypersensitive variety changed shorter and disease infection increased with the light weakened,but the changing range was limited.Obvious difference existed between two varieties.Qianmai 7 behaved resistance to powdery mildew in any conditions.

Key words: Wheat, Powdery mildew, Germination, Enviromental factor

CLC Number: 

• S435.1+4