玉米瘤黑粉病菌生物学特性研究

对影响玉蜀黍黑粉菌冬孢子萌发和双核菌丝生长的生物学特性进行研究。结果表明,冬孢子萌发最适温度为30℃,pH为3,碳源为蔗糖、麦芽糖和葡萄糖,氮源为半胱氨酸、天冬氨酸和甘氨酸;双核菌丝生长的最适温度为30℃,pH为8,碳源为葡萄糖和蔗糖,氮源为天冬氨酸、半胱氨酸和甘氨酸。光照条件对冬孢子萌发和菌丝生长的影响不显著。

Biological Characteristics of Ustilago maydis

The physiological race of Exserohilum turcicum was identified among 113 isolates collected from 28 areas of Liaoning, Jilin and Heilongjiang provinces in 2009 on maize inbred lines with Ht1, Ht2, Ht3 and HtN resistance genes, and its population dynamics was investigated. The results showed that 12 races were identified among these fungal isolates, including 0, 1, 2, 3, N, 12, 13, 1N, 2N, 123, 12N and 123N. Those races can not only infect the maize with single Ht gene, but also that with all kinds of resistance gene, and it meant the race component was in pluralistic. Among these races population, races 0 and 1 were predominant with occurrence frequency of 47.8% and 19.5%. The virulence frequencies against genes Ht1, Ht2, Ht3 and HtN were 37.2%, 21.2%, 4.4% and 15.9%, respectively. The physiological differentiation of E. turcicum was obvious, and their distribution and inter-specific variability also became complex. The increasing epidemic of northern maize leaf blight in northeastern China was ascribed to the increasing virulence frequencies of such major races as 0 and 1, and the resistance losing of the cultivars.