ISHS Acta Horticulturae 234: VII International Symposium on Virus Diseases of Ornamental Plants
EFFECTS OF TEMPERATURE ON EXPRESSION OF CHRYSANTHEMUM SLOW DECLINE IN CHRYSANTHEMUM MORIFOLIUM |
| Authors: | R.H. Lawson, H.T. Hsu |
| Abstract:
Chrysanthemum morifolium cultivars of the Mountain group and White Sands are affected by growth abnormalities described as chrysanthemum slow decline. This condition is associated with stunting, leaf distortion, rugosity, and abnormal flower development. Populations of cvs Mountain Peak and White Sands showed differences in severity of disease symptoms among plants growing in a greenhouse with flucuating light and temperature. Propagations from these plants were maintained as clones that showed mild or severe symptoms similar to the original plants. Mild and severe symptom types of Mountain Peak and White Sands were maintained as separate clones in all experiments. Plants with severe symptoms growing in a greenhouse also showed severe symptoms when grown at 18°C with a 16-hour light period and 15.5°C dark period (low temperature environment). Plants of the same clone grown at a 24°C/21°C (high temperature) light and dark period showed more mild symptoms. Cuttings from plants showing mild symptoms in the greenhouse also showed mild symptoms when grown at the low temperature regimen. Plants with mild symptoms were nearly symptomless when exposed to the higher temperatures. Both Mountain Peak and White Sands cultivars responded similarly. Expression of slow decline could be rapidly modified with the development of more mild symptoms by shifting plants with severe symptoms at low temperature to the high temperature environment. Similarly, plants with mild symptoms expressed a more severe decline reaction when plants at high temperature were shifted to the low temperature environment. These results may be useful in screening germplasm in selecting improved chrysanthemum genotypes with more normal growth in seedling populations or cultivars that are predisposed to expression of slow decline. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
