棉枯萎病菌在不同生态环境中的存活及致病力研究

EVALUATION OF SURVIVAL AND PATHOGENICITY FOR FUSARIUM WILT PATHOGEN OF COTTON IN DIFFERENT ECOLOGICAL ENVIRONMENTS

从棉枯萎病菌在土壤,水中及病株残体内的存活和致病力研究结果,看出病菌在干旱土壤内可存活5年,干棉茎内存活达6年之久;在较高温条件下,淹没水中的棉病茎,27天后未分离出病菌;病菌的致病力是随着保存年限的增加而降低,以3个生理型的5个菌系比较,其降低的程度菌系间差异不显著。表明棉枯萎病菌确属生存力强的一种病原真菌,病田旱地轮作4年以上发病才有所减轻,但不能消灭病原,带病枝、茎淹没于清粪水中,病菌易于死亡,选择强菌系寄主中当年分离的病菌是建立人工病圃进行品种选育的最好菌原。

The pathogen of Fusarium oxysporum f.sp. vasinfectum was isolated from soil, water and infected plant debris and tested to determine its survival and pathogenicity. The results showed that the fungus could survive for 4 years in dry infected soil and 6 years in dry infected plant debris, respectively. However, it could not be isolated from infected plant debris placed at higher tempra-ture condition and in water after 27 days. Rotations of more than 4 years in infected soil generally reduced incidence and severity of disease. The virulence of the pathogen decreased with increasing storage period, but no significant difference was found among five races of three pathotypes. It was easy to kill the pathogens in infceted stalks and leaves through flooding them in light manure water. The highly virulent races isolated from infceted hosts in current yea are the best pathogen source for artificial inoculated nursery of breeding for cotton resistance to Fusarium wilt.