Evaluation of wild Dianthus accessions for resistance to bacterial wilt (Pseudomonas caryophylli)

Abstract

Bacterial wilt (Pseudomonas caryophylli) is one of the most important and damaging diseases of carnations (Dianthus caryophyllus) in Japan. It causes serious crop losses in carnations grown in the warm districts. Almost all carnation cultivars are susceptible to bacterial wilt. Therefore, 70 wild Dianthus accessions were screened for resistance to bacterial wilt by using the cut-root soaking method with an inoculum concentration of 107 cfu (colony-forming units) · ml-1. Large differences in resistance were observed among 70 Dianthus accessions. We found two highly resistant wild species, D. capitatus ssp. andrzejowskianus and D. henteri. These 2 species showed no disease symptoms throughout the experiment. Moreover, 7 accessions were classified as resistant. Retesting by using 4 isolates showed that D. capitatus ssp. andrzejowskianus was the most resistant species.