大豆对紫斑病抗性鉴定方法的研究

METHOD OF IDENTIFYING RESISTANCE TO PURPLE SEED STAIN (CERCOSPORA KIKICHII) OF SOYBEAN

本研究通过自然发病和人工接种鉴定了不同大豆品种对紫斑病的抗性 ,旨在建立大豆对紫斑病抗性鉴定方法 ,为大豆品种资源抗性筛选创造条件。对不同成熟期的 37个大豆品种在自然条件下对紫斑病的抗性调查结果表明 ,大豆紫斑病的发生受气候条件、大豆成熟期和品种抗性的影响 ,由于避开了病害发生的有利时期 ,晚熟大豆品种紫斑病发生很轻或不发病。 1998年和 1999年 ,分别在防虫网室和温室人工接种鉴定 4 5份大豆种质 ,两次的鉴定结果均表明大豆品种间对紫斑病的抗病性存在显著差异 ,但在温室条件下大豆紫斑病平均病情指数显著低于网室条件下的试验结果。为提高大豆对紫斑病抗性鉴定的准确性 ,建议不同成熟期的品种同期鉴定时可对早熟品种进行摘花 ,保证接种时接种荚荚龄一致 ;对接种荚进行标记 ;设立高感对照 ;

Natural incidence of purple seed stain incited by Cercospora kikuchii was investigated in 37 soybean cultivars belonging to MG 0-Ⅷ. The results showed that incidence of purple seed stain was affected by weather condition, maturing stage and resistance of soybean cultivars. Late-maturing cultivars appearing resistance to natural infection might be due to disease escape rather than genetic resistance. 45 soybean cultivars were identified for resistance to seed infection by artificial inoculation with C. kikuchii in screenhouse in 1998 and in greenhouse in 1999. Significantly resistant difference to purple seed stain among cultivars was discovered in two tests. However, average value of disease index of 45 cultivars for greenhouse test was much lower than that for screenhouse test. In order to accurately evaluate the resistance of soybean to purple seed stain, It was suggested that the maturing times of cultivars are synchronized by picking off flowers of early-maturing cultivars at the early flowering stage, tag and investigate the inoculated pods. In addition, high susceptible cultivars are need for control. The resistant cultivars must be identified for two or more times.