Breaking dormancy in kiwifruit with chilling or chemical treatments

Abstract

Chilling is required to overcome bud donnancy in kiwifruit (Actinidia deliciosa (A.Chev.) C.F. Liang et A.R. Ferguson), and yields may be much higher following a cold winter than after a wann winter. Although 4°C has been used as the base temperature for chilling requirement studies, chilling requirements for ‘Bruno’ kiwifruit may be met at a higher base temperature. A comparison of minimum temperatures during two winters suggests that differences in degree-hours below 10°C may be critical. Differences resulting from variations in winter chilling may be unimportant at low altitudes, where chilling and budburst are always poor, and at high altitudes, where chilling is always adequate. Hydrogen cyanamide partially compensates for the chilling deficiency of ‘Bruno’ vines to break bud donnancy but does not enhance flower initiation and development, which is also induced by chilling.

Keywords:

• kiwifruit
• Actinidia deliciosa
• dormancy
• altitude
• cyanamide