关键词: 水稻干尖线虫, “小穗头”, 线虫分布, 种子饱满度, 线虫死亡率

Abstract: 【OBJECTIVE】 In order to investigate the relationship between Aphelenchoides besseyi and the symptom of small grains and erect panicles, which was an important rice disease in jiangsu province. 【METHOD】Greenhouse experiments were designed by inoculating different numbers of Aphelenchoides besseyi on seedling bud and vagina of two Oryza sativa cultivars Zhendao No.2 and Wuyunjing No.7. The effect of small grains and erect panicles to rice growth was revealed through observing the disease development, seed expansion stages, the number of nematodes loaded in grains and nematode mortality caused by Aphelenchoides besseyi. 【RESULTS】The height, length and the numbers of spikelets of unhealthy panicles of Zhendao No.2 were decreased 6.7%, 16.4%, 13.5% respectively compared to healthy one. The distribution of nematode reproduction on rice was demonstrated that the percentage of infested seed and the number of nematode loaded were highest in normal expansion seeds with well developed endosperm, while lowest in empty seeds. The mortality of nematodes on grain was declined as the number of nematode loaded was rising, retaining lower level in plump seeds. 【CONCLUSION】Results indicated that Aphelenchoides besseyi was the pathogen of small grains and erect panicles. Wuyunjing No.7 just manifested small grains and erect panicles without the symptom of white-tip leaves. This phenomenon showed that the symptom of small grains and erect panicles was the new symptom of disease caused by Aphelenchoides besseyi on rice.

Key words: Aphelenchoides besseyi, small grains and erect panicles, nematode distribution, seed expansion, nematode mortality