ISHS Acta Horticulturae 234: VII International Symposium on Virus Diseases of Ornamental Plants
THE EFFECT OF TEMPERATURE AND LIGHT ON CHRYSANTHEMUM STUNT VIROID INFECTION OF FLORISTS CHRYSANTHEMUM |
| Authors: | M.K. Handley, R.K. Horst |
| Abstract:
Chrysanthemum stunt disease, a serious disease of florists chrysanthemum caused by chrysanthemum stunt viroid (CSV), has been detected by graft inoculations to indicator cultivars of chrysanthemums and by polyacrylamide gel electrophoresis (PAGE) to detect viroid-specific RNA bands. This investigation used both PAGE and bioassay for detecting CSV under a range of environmental conditions. Chrysanthemum stunt viroid was influenced by several environmental parameters. Symptom progression and final disease severity, as well as the amount of extractable viroid RNA, varied with temperature, light intensity, and photoperiod, altered individually and in combination. Symptom expression was greatest between 26 and 29 C, but maximum viroid titer occurred between 22 and 26 C when light intensity and photoperiod were constant. Mild symptoms occurred under short (8 h) daylengths, although viroid titers were not affected when temperature and light intensity did not vary. High light intensities of 45 klux generally favored symptom development and viroid titer. An interaction was found in light and temperature effects on disease development. Light intensity appears to partially compensate for an unfavorable temperature: high light intensity (44 klux) enhances symptoms at 22 C and lower light (16 klux) at 30 C. Therefore, it is apparent that environmental conditions must be controlled to obtain meaningful data for investigations with CSV. | |
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