腐皮镰刀菌病原致病性及苜蓿品种抗病性研究

An evaluation of the pathogenicity of Fusarium solani and disease resistance of alfalfa varieties

为了探明腐皮镰刀菌对紫花苜蓿种苗的致病性,本研究采用常规组织分离法从苜蓿根部分离纯化真菌,对分离得到的菌株进行形态学结合分子生物学的鉴定,并以菌饼放置种子的方法,分别以水琼脂培养基(water agar,WA)和马铃薯葡萄糖琼脂培养基(potato dextrose agar,PDA)对22个紫花苜蓿品种的种子进行试验,在14 d测定相对根长、相对苗长、相对根苗长度比、相对发芽率和病情指数,并通过隶属函数综合各个指标,对22个苜蓿品种的抗病性进行评价。结果表明:腐皮镰刀菌为导致苜蓿根腐病的病原真菌;在两种培养基质上,腐皮镰刀菌对22个苜蓿品种均有致病性,且在PDA培养基上的致病性强于WA培养基;参试的22个苜蓿品种之间抗病性有所差异,塔苜5S的抗病性最强,中苜1号、Bara310SC、乐寒F3和金皇后的抗病性较强,中兰2号、赛迪7、龙牧803和甘农3号的抗病性较弱,Paola的抗病性最弱。

The objective of this study was to evaluate the pathogenicity of a range of Fusarium solani isolates to various alfalfa varieties on two culture media,potato dextrose agar(PDA)and water agar(WA)medium.We used conventional tissue separation methods to isolate and purify the fungi from alfalfa roots,and the representative strains of the isolates were identified using both morphological and molecular techniques.We estimated the relative root length,relative seedling length,relative root to seedling ratio,relative germination rate and disease index at 14 d after inoculation with F.solani,and synthesized various indexes through membership functions.The results showed that F.solani was the pathogenic fungus causing alfalfa root rot.F.solani was pathogenic to 22 alfalfa varieties on both culture media,and the pathogenicity of F.solani on PDA medium was stronger than that on WA medium.The disease resistance of the 22 alfalfa varieties varied.‘TARIMU 5S’showed the strongest resistance,while‘Zhongmu No.1’,‘Bara310SC’,‘OPTIMUS F3’and‘Golden-queen’exhibited high-level resistance.‘Zhonglan No.2’,‘Sardi 7’,‘Longmu 803’and‘Gannong No.3’exhibited low-level resistance;‘Paola’had the weakest resistance.