Chrysanthemum stunt viroid

Abstract

The chrysanthemum stunt viroid (CSVd) is a small, single-stranded, infectious RNA forming a circular secondary structure, whichbelongs to the Pospiviroidae family and mainly infects certain species and cultivars of Compositae and Solanaceae. The effects on cultivated chrysanthemum are severe, including stunting of plant height, reduced flower size, and flower color bleaching. However, theexpression of the symptoms depends on the chrysanthemum cultivars. CSVd is known to be readily transmitted by sap, but the infectionrate and incubation period were observed to differ according to the varieties. Some CSVd-resistant cultivars have also been reportedand the resistance is heritable in crosses between a CSVd-resistant chrysanthemum cultivar and CSVd-susceptible cultivars.