海南岛西瓜,青瓜和毛瓜枯萎病菌致病性的初步研究

从海南岛种植区的西瓜上分离到11个尖镰孢菌株，青瓜和毛瓜上分离到3个尖镰孢菌株。用胚根接种法将这些菌株接种到西瓜（品种为新红宝）、青瓜（品种为大青吊瓜）和毛瓜（品种为菠萝种）上，以测定其对西瓜、青瓜和毛瓜的致病性。结果表明，所有参试菌株都可引致参试寄主品种表现枯萎病症状；从西瓜上分离到的11个菌株，有8个菌株为尖镰孢西瓜专化型，2个为尖镰孢黄瓜专化型，1个用胚根接种法无法确定其专化型；8个尖镰孢西瓜专化型菌株对西瓜的致病性之间具有显著性差异，表明存在1个以上的生理小种：从毛瓜上分离到的2个菌株属于尖镰孢西瓜专化型，但可能不是同一生理小种；从青瓜上分离到的1个菌株属于尖镰孢黄瓜专化型。

Pathogenicity of Wilt Pathogens from Watermelon,Cucumber and Chieh-qua

A total of 14 Fuarium oxysporum isolates were obtained from wilt plants ofwatermelon(Citrullus lanatus(thunb) Mansfeld), cucumber(Cucumis sahvus L.) and chiehqua(Benincasa hispida Cogn. var. Chieh-que How.) in Hainan Island. These fungi wereinoculated on to the seedlings of watermelon, cucumber and chieh-qua. All the plantsinoculated showed wilt symptoms. The pathogenicity measured by disease percentageamong the isolates was significantly different. of the 11 isolates derived from watermelon,8 belonged to F. oxysporum (Schlecht.) f. sp. nivem (E.F. Smith) Synder et Hansen, 2to F. oxysporum (Schl.) f. sp. cucumerinum Owen, and 1 not identified yet. All the 2isolates horn chieh-qua were identitied as F. oxysporum (Schlecht.) f. sp. nivem (E. F.Smith) Synder et Hansen, and 1 isolate from cucumber as F. oxysporum (Schl.) f. sp.cucumerinum Omen. It was inferred that there should be more than one physiologicalrace withen F. Oxysporum (Schlecht) f. sp. nivem (E. F. Smith) Synder et Hansen inHainan Island.