水稻恶苗病病原菌的研究

STUDIES ON THE PATHOGENS OF THE RICE BAKANAE DISEASE IN ZHEJIANG

1977～1987年采集103个稻恶苗病标本,分离后获8种镰刀菌。其中串珠镰孢(Fusarium moniliforme)的一个变种占总标本数的60.2%,其特征为:菌落生长直径2—4cm;大型分生孢子镰刀形,3—5隔;小型分生孢子卵形,串生和假头生;产孢细胞单、复粳并存;具厚垣孢子,球至亚球形。此变种定名为(F. moniliforme var. Zhejiangensis Wang et Chen var. nov.)。其他7种镰刀菌为木贼镰孢(F. equiseti),禾谷镰孢(F. graminearum),砖红镰孢(F. lateritium),雪腐镰孢(F. nivale),尖镰孢(F. oxysporum),半裸镰孢(F. semitectum),腐皮镰孢(F. solani)。试验证明,串珠镰孢浙江变种是水稻恶苗病的主要致病菌;其他6种(除腐皮镰孢未接种外)均有不同程度的弱致病性。串珠镰孢浙江变种也能侵染小小麦、大麦、玉米、西瓜、豌豆等作物的幼苗,并有徒长症状。

103 rice seedlings showing symptoms of Bakanae disease were collected during 1977-1987 in Zhejiang Province. Eight species isolated were Fusarium moniliforme var. zhejiangensis Wang et Chen var.nov.,60.2%; F. semitectnm, 9.7%; F. graminearum, 7.8%; F. equiseti, 7.8%; F. oxysporum, 5.8%; F. nivale, 4.9%; F. solani,2.9%; F. lateritium,1%,In culture, macroconidia of F.moniliforme var. zhejiangensis were falcat with 3-5 septae; microconidia were oval to elliptical, catanulate or in false heads with conidiogenous cells of polyphialide type and simple phialidic type; chlamydospores were globose to subglobose. Inoculation tests demonstrated that F,moniliforme var. zhejiangensis was the predominant pathogen causing Bakanae disease in Zhejiang Province. The pathogen could also infect the seedlings of wheat, barley, corn, watermelon and pisi. After inoculation, the seedings showed the 'bakanae' symptoms with the exception of F. solani which was not include in the tests, the remaining six species showed varying degrees of weak pathogenicity on rice seedlings.