Incidence of Coleus blumei viroid 1 in Seeds of Commercial Coleus in Korea

A viroid was detected from symptomless Coleus blumei cultivar 'Kong Scarlet'. It consisted of 249 nucleotides(GenBank accession no. EU410620), which was 100% identical to a Coleus blumei viroid 1(CbVd 1) reported from China(GenBank accession no. DQI78399), indicating that the viroid was an isolate of CbVd1. Attempts were made to determine if commercial Coleus seeds were infected with CbVd. Infection rates in seedlings of the 14 commercial cultivars of Coleus ranged from 0 to 100%. CbVd1 caused discoloration and growth retardation in some cultivars, but is symptomless in others. These results indicated that Coleus in commercial markets in Korea is highly infected with CbVd.