ISHS Acta Horticulturae 309: XV International Symposium on Fruit Tree Diseases
RAPID BIOLOGICAL DETECTION OF APPLE SCAR SKIN VIROID |
| Authors: | W.E. Howell, G.I. Mink |
| Abstract:
Two apple cultivars (Malus domestica), Stark's Earliest and Sugar Crab, were effective as rapid indicators of the apple scar skin viroid. Distinct fruit marking or leaf epinasty symptoms developed within two months when one-year-old apple seedlings were chip budded with dormant flower or with vegetative buds of these indicators and with two inoculum chips placed just below the indicator bud. Developing flowers were hand pollinated to insure fruit set. Fruit produced on inoculated greenhouse-grown trees displayed characteristic symptoms of color dappling and cracking of the calyx end. Epinasty of young expanding leaves appeared on vegetative shoots of both cultivars 6 to 8 weeks after inoculation when grown at 24-hour photoperiods at 18 or 28°C. While similar leaf symptoms occurred on some trees held under 14-hour photoperiods at these same temperatures, no epinasty occurred on trees under 4-hour photoperiods. No leaf epinasty occurred on trees held at 38°C under any light regime. | |
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