Kiwifruit: Frost tolerance of plants in controlled frost conditions

Abstract

Abstract Kiwifruit ( Actinidia deliciosa (A. Chev.) C. F. Liang & A. R. Ferguson var. deliciosa ) plants were subjected to controlled advective frosts in the autumn, winter, or spring and injury symptoms were recorded. The plants naturally hardened in autumn and early winter and rapidly dehardened in spring; temperatures lower than −5, −7, −6.5, and −0.5°C respectively in May, June, July, and September caused injury to plants of ‘Hayward’ cultivar, and all plants in the test population were killed at temperatures below −9°C in May and 67% were killed at −13°C in June. With respect to damage incidence and subsequent bud break, plants of ‘Bruno’ cultivar appeared to be slightly less frost tolerant than ‘Hayward’ plants in May and in June but these cultivar differences were minor.