Full Length Research Paper

ISSR for comparison of cross-inoculation potential of Colletotrichum capsici causing chilli anthracnose

Kanchalika Ratanacherdchai^1*, Hong-Kai Wang², Fu-Cheng Lin² and Kasem Soytong³

¹International College, King Mongkut’s Institute of Technology Ladkrabang, Ladkrabang, Bangkok 10520, Thailand.

²Biotechnology Institute, School of Agriculture and Biotechnology, Zhejiang University,

Hangzhou 310029, P. R. China.

³Department of Plant Pest Management Technology, Faculty of Agricultural Technology, King Mongkut’s Institute of Technology Ladkrabang, Ladkrabang, Bangkok 10520, Thailand.

*Corresponding author. E-mail: kan_cha_lika@yahoo.com Tel: +66-2326-4072.

Fax: +66-2326-4108.

Accepted 9 November, 2009

   Abstract

Thirty-four isolates of Colletotrichum spp. including 2 species, Colletotrichum gloeosporioides and Colletotrichum capsici, from anthracnose on Bell pepper, Long cayenne pepper and Bird’s eye chilli were isolated and their pathogenicity was proven via fruit inoculation. Pathogenicity tests divided pathogenic potential into low, medium and high virulence groups. It is clearly revealed that C. capsici from the three tested hosts expressed the highest virulent isolates. Cross-inoculation of three high virulent isolates of C. capsici in accordance with three chilli varieties showed that all isolates could produce anthracnose symptom in the same lesions. All tested isolates developed lesions after co-inoculation of all hosts. Inter simple sequence repeat (ISSR) analysis indicated that there are two distinct groups of C. gloeosporioides and C. capsici. Furthermore, genetic diversity was correlated with geographic distribution, while there was no clear relationship between genetic diversity and pathogenic variability. But it is clearly demonstrated that whereas C. gloeosporioides appears in the same geographic area as C. capsici, it causes lower disease incidence.

Key words:  Anthracnose, chilli, Colletotrichum capsici, cross-inoculation.