广东地区黄瓜疫病病原的分离与鉴定

华南地区高温高湿的气候容易引起黄瓜疫病的爆发，对黄瓜生产构成严重威胁。通过对广东各黄瓜主产区的黄瓜疫病菌进行分离、鉴定，确定广东地区黄瓜疫病的病原，并测定该病原菌对不同瓜类蔬菜的致病力，为瓜类疫病防治提供实验依据。从广东各黄瓜主产区感染疫病的黄瓜茎、叶上分离到疫霉菌共8份，并对其进行形态学观察和ITS序列比对研究。发现广东各黄瓜主产区的疫霉菌均为瓜类疫霉（P. melonis），人工接种对其致病力研究发现，该疫病菌对黄瓜、印度南瓜、节瓜、冬瓜致病力较强，而对丝瓜致病力较弱。明确广东地区黄瓜疫病的病原菌是瓜类疫霉（P. Melonis），在人工接种条件下，该病原菌对不同瓜类的致病力存在较大差异。这些研究结果对瓜类疫病的防治及抗疫病育种具有重要的指导意义。

Isolation and Identification of Cucumber Blight Pathogens in Guangdong Area

The climatic conditions of high temperature and humidity in southern China contribute to the outbreak of cucumber blight, which is a serious threat to cucumber production. Cucumber blight pathogens from main producing areas of cucumber in Guangdong are isolated and identified to make clear the pathogen(s) of cucumber blight in Guangdong areas, and then, the pathogenicity on different melon vegetables, which is an experimental basis for melon blight disease prevention and control. Eight isolates collected from stems or leaves of infectious different cucumber cultivars planted in cucumber main producing areas of Guangdong were analyzed by morphologic observation and ITS sequence alignment and the results showed these isolates were identified as Phytophthora melonis Katsura. Under artificial inoculation, Phytophthora melonis Katsura identified exhibited certain differences in the pathogenicity on other cucurbits such as Cucurbita maxima, chieh-qua, Benincasa hispida and Luffa cylindrical, among them, Luffa cylindrical showed the highest resistance against Phytophthora melonis Katsura. The results are important for melon blight disease control and and resistance breeding in the future.