小麦的种和品种对白粉病抗性的初步研究

 在对白粉病具不同抗性的11个小麦的种和品种上进行的按种试验表明,在接种后8小时内,分生孢子达到最高萌发率(约为60%),并形成附着孢。在抗病的和感病的小麦叶片上,分生孢子的萌发率和萌发速度没有差异。接种后12小时,在感病的材料上,发现真菌侵入寄主,但在抗病的材料上,发现最早侵入时间,至少要比在感病材料上约晚4小时。接种后36小时,在高感的材料上,萌发的分生孢子有83%已侵入寄主,其中约有70~80%已形成吸胞。在感病、抗病和高抗材料上的侵入率,分别为70,45,27%。形成或开始形成吸胞的分别为55~61,14~27,4~8%。在抗病材料的表皮细胞内,真菌形成的吸胞较小,并有点畸形。在抗病材料的叶面上,真菌的菌丛稀薄,产孢也很少。

VARIETAL RESISTANCE OF WHEAT TO POWDERY MILDEW

Seedlings of wheat species and varieties resistant or susceptible to powdery mildew were inoculated with conidia of Erysiphe graminis tritici.About 60% of the conidia germinated and formed appressoria within 8 houra after inoculation.The percentage and rate of conidia germination on the leaf surface of resistant and susceptible wheat varieties showed no difference at the early stage of infection.The difference became apparerent at the stages of penetration and further development.Earliest penetration was observed on the highly susceptible group 12 hours after inoculation 83% of germinated conidia to penetrate within 36 hours.Less germinated E.graminis tritici conidia penetrated into leaves of resistance varieties of wheat than into those of susceptible ones.During 36 hours,the percentage of penetration of the susceptible,resistant and highly resistant varieties were 65,45,27% respectively.
The haustorial formation in the case of resistant varieties delayed,and the haustoria developed in the epidermal cell of resistant varieties were smaller.
On resistant plants developed fewer,less dense colonies with less sporulation than on the susceptible plants.