Winter hardiness of micropropagated and conventionally propagated strawberry plants

Abstract

SummaryEnhanced vigour of micropropagated strawberry (Fragaria X ananassa Duch.) plants has given cause to suspect their winter hardiness to be inferior to that of conventionally propagated plants. This experiment was carried out to examine and compare cold hardiness and overwintering of three types of strawberry plants of cultivars Senga Sengana and Jonsok: 1) micropropagated virus-free elite plants, 2) certified plants (runner plants from elite plants), and 3) ordinary plants (runner plants of conventionally propagated plants from a strawberry farm). A special “double pot”-method was developed and used in planting so that the plants could be lifted for controlled freezing tests during winter. Additionally, winter survival was evaluated in the field during flowering. In controlled freezing tests, strawberry crowns survived -8°C without injury, suffered minor injury at -10°C and severe injury at -12°C. No consistent differences in cold hardiness among the three types of plants were detected during winter. Field evaluation did not reveal any differences in their winter survival, either. Micropropagated plants flowered more freely than did the plants produced through runners.