青稞镰孢根腐病病原鉴定及致病性分析

Pathogens Identification and Pathogenicity Analysis of Fusarium Root Rot on Naked Barley

为明确青稞镰孢根腐病的病原,于青稞苗期及成株期分别对甘肃省甘南藏族自治州合作市、临潭县和卓尼县等青稞主产区的根腐病发生情况进行调查并采集样品,采用常规的组织分离法分离其病原,结合形态特征和分子生物学进行病原鉴定,并用烧杯水琼脂法和盆栽法测定其致病性。结果表明,青稞镰孢根腐病在甘肃省甘南藏族自治州分布广泛,发病率在5%~20%之间。发病植株长势弱、发黄,茎基部缢缩、腐烂,穗白粒瘪,茎秆发褐或黑红。共分离得到88株青稞镰孢根腐病病原菌,苗期50株,成株期38株,经鉴定分别为燕麦镰孢Fusarium avenaceum、木贼镰孢F.equiseti、三线镰孢F.tricinctum、柔毛镰孢F.flocciferum、锐顶镰孢F.acuminatum及F.langsethiae。盆栽法和烧杯水琼脂法所测得的致病性差异显著,但均表明燕麦镰孢综合致病力较强,结合其分离率,确认燕麦镰孢为优势病原。

In order to clarify the pathogen of naked barley Fusarium root rot in Hezuo city, Lintan County, Zhuoni County, Gannan Tibetan Autonomous Prefecture, Gansu Province, the occurrence of naked barley root rot was investigated at seedling stage and adult stage and samples were collected. The pathogen was separated by the conventional tissue separation method.The classification status of pathogens was determined by combining morphological characteristics with molecular biological identification, and the pathogenicity was determined by beaker-water agar and pot-culture method. The results showed that the naked barley Fusarium root rot was widely distributed in Gannan Tibetan Autonomous Prefecture of Gansu Province, and the occurrencerate was between 5% and 20%.The disease plant was weak and yellow, with constricted and rotted stem base, white ear, hollow grain and brown or dark red stem.A total of 88 strains of naked barley Fusarium root rot were identified, including 50 strains at seedling stage and 38 strains at adult stage. They were identified as Fusarium avenaceum,F.equiseti,F.tricinctum,F.flocciferum,F.acuminatum and F.langsethiae. The difference of pathogenicity between pot-culture with beaker-water agar method was significant, but both indicated that F.avenaceum had strong comprehensive pathogenicity. Combined with its isolation rate, F.avenaceum was confirmed as the dominant pathogen.