中国水稻干尖线虫部分群体对水稻的致病力测定

Virulence of Part Populations of Aphelenchoides besseyi on Rice in China

为了解不同地理群体和寄主群体的中国水稻干尖线虫对水稻的致病力差异,通过室内水稻盆栽接种试验,对来自中国6个省、2种不同寄主植物上的水稻干尖线虫8个群体的致病力进行了测定和分析。结果表明,供试的8个水稻干尖线虫群体均能侵染供试的3个水稻品种,但不同群体对水稻同一品种的致病力,以及同一群体对不同水稻品种的致病力均存在差异;不同水稻品种被侵染后的症状也存在差异,仅有辽盐16被所有群体侵染后均表现"干尖"症状,武育粳3号和博优998没有明显"干尖"症状。供试的3个水稻品种接种水稻干尖线虫后均能抽穗,但是株高、穗长、单株穗数和千粒重受到不同程度的影响。此外,水稻干尖线虫对水稻的致病力与群体寄主相关,来自草莓的水稻干尖线虫群体对水稻的致病力明显弱于来自水稻上的群体;在供试的水稻干尖线虫群体中,HN-2群体对水稻品种辽盐16的生长影响最大,但在稻株上的虫量最少,显示该群体繁殖数量不大,但具有较强的致病力。这说明水稻干尖线虫在水稻上的繁殖数与致病力之间并不一定呈正相关。这些结果表明中国的水稻干尖线虫可能存在不同的生理小种或致病型。

In order to reveal the pathogenic difference of Aphelenchoides besseyi populations from different geographic regions and hosts in China, a virulence investigation of eight populations of A. besseyi from six provinces on rice were carried out on potted rice in greenhouse. Among the eight populations of A. besseyi, one were extracted from the strawberry （Fragaria ananasa） and seven from rice. The results showed that all the eight populations of A. besseyi infected 3 varieties of rice （Liaoyan 16, Wuyujing 3 and Boyou 998）, but their virulence varied with rice variety and nematode population, infection with nematodes caused various symptoms on different rice varieties with typical symptom of ＂white tip＂ on Liaoyan 16, but without obvious symptoms on the other two. All the varieties inoculated with nematodes could tassel, but their plant height, panicle number per plant, panicle length and 1000-grain weight were affected to various degree. The results also showed that the virulence of A. besseyi was related to the origin of host. The population of A. besseyi from the strawberry had weaker virulence than those from rice. In addition, among all the eight nematode populations, infection by HN-2 greatly inhibited the growth of Liaoyan 16 with least nematode. It indicated that this population had stronger virulence than the others. It also showed that there was no positive correlation between the propagation number and virulence of A. besseyi. All the results indicated that there may be different physiological races or pathotypes of A. besseyi in China.