红麻种子携带真菌与苗期病害发生的关系

Relationship between kenaf seed borne fungi and the seedling diseases

为查清红麻苗期病害的初侵染源,用平皿测定法对参试17份品种种子进行带菌检查、分离鉴定和接种试验,并对42份品种苗期病情作系统观察.结果表明:红麻种子表面携带真菌有12个属14个种,其优势菌群为交链孢菌(Alternaria)、枝孢菌(Cladosporium)、镰刀菌(Fusarium)、青霉菌(Penicillium)、曲霉菌(Aspergillus)、根霉菌(Rhizopus)和毛霉菌(Mucor)等,不同产地种外带菌种类有异;种子内部潜伏镰刀菌、枝束梗孢菌(Synnematium)、交链孢菌、炭疽菌(Colletotrichum)和葡萄孢菌(Botrytis)等5个属.红麻苗期主要病害为立枯病(Rhizoctoniasolani)、灰霉病(Botrytiscinerea)、茎枯病(Corynesporacassiicola)、炭疽病(Colletotrichumhibisci)和枯萎病(Fusariumvasinfectum).种子携带真菌多数是腐生菌,少数为寄生菌,是引起苗期炭疽病、灰霉病和枯萎病发生的重要初侵染源.立枯病来自土壤带菌,茎枯病尚不明确.

In order to make clear of the original infection pathogens of the seedling diseases, the pathogens of seeds of seventeen kenaf varieties were isolated and identified by petri-dish testing and inoculation tests were made, the disease indexes of forty-two varieties at the seedling stage were systemically observed. The results showed that fourteen species of fungi belonging to twelve genera were carried on the surface of kenaf seeds, of which Alternaria, Chadosporium, Fusarium, Penicillium, Aspergillus, Rhizopus and Mucor were main seed borne fungi. While the fungi species on surface of seeds from different places were significantly different. Five genera were seed borne fungi inside, which were Fusarium, Synnematium, Alternaria, Colletotrichum and Botrytis. The main pathogens of kenaf seedling diseases were Rhizoctonia solani, Botrytis cinerea, Corynespora cassiicola, Colletotrichum hibisci and Fusarium vasinfectum. The most of the seed borne fungi were saprophytic, while the minority of them were parasitic, which are the important pathogens of original infection resulting in anthracnose, gray mould and blight at seedling stage. However the pathogen of original infection of rhizoctonia was soil borne fungi and that of stem blight was not clear.