Critical freeze damage temperatures of flower buds of kiwifruit ( Actinidia chinensis Planch.)

Controlled freezing tests in the laboratory were undertaken on both dormant and extending kiwifruit shoots ( Actinidia chinensis Planch., cvs Hayward and Abbott) collected from vines at Auckland. Damage occurred to buds on dormant shoots at temperatures below –10 ° C. At later stages of bud and shoot development, when spring growth had commenced, up to 10% of flower buds were damaged after 30 min exposure to ‐1.5 to ‐2.0 ° C. The extent of damage increased with time of exposure at these temperatures. Some method of preventing freeze damage may be necessary to cultivate kiwifruit vines successfully in areas that are likely to experience temperatures of ‐1.5 to ‐2.0 ° C during spring.