一种新大豆豆荚炭疽病症状类型及其病原鉴定

通过病原菌分离、形态学观察、核糖体DNA ITS序列分析和致病性试验,研究引起鲜食大豆"台75"豆荚普遍出现条状不规则形病斑的原因.结果显示,条状不规则形病斑是由平头炭疽菌Colletotrichum truncatum引起的一种新的大豆豆荚炭疽病症状,该病原菌引起豆荚炭疽病症状主要有2种,一种是圆形斑,另一种是条状不规则斑即锈斑.在供试的7种大豆品种中,条状不规则斑主要出现在"台75"上,其余6个品种主要是圆形斑;"台75"条状不规则斑的病荚率为65.37%,其余品种上的病荚率分别为1.02%、1.87%、2.95%、3.56%、9.32%和12.25%.研究表明由平头炭疽菌引起的大豆豆荚炭疽病的症状类型与寄主品种相关.

A new symptom type of soybean pod anthracnose and identification of its pathogen

The objective of this study is to explore the pathogen of stria-like lesions epidemically appeared in the pods of soybean variety "Tai 75" in China. Based on the pathogen isolated, morphological observation, rDNA ITS sequence analyses and pathogenicity tests, it is demonstrated that the lesion is a type of infection symptoms caused by fungal pathogen Colletotrichum truncatum (Schwein.) Andrus & W. D. Moore. The same pathogen infects soybean pods resulting in two main types of symptom on various soybean varieties. The stria-like lesions appeared exclusively in the soybean variety "Tai 75" whereas the round-blotches were observed with the other 6 soybean varieties tested. Pod disease incidence of stria-like lesions in the soybean variety "Tai 75" was 65.37%, whereas in the other 6 soybean varieties tested was 1.02%, 1.87%, 2.95%, 3.56%, 9.32%, 12.25%, respectively. The results showed clear host- and variety-dependent characteristics of infection of fungus C.truncatum.