Low-chill trait for endodormancy completion in Actinidia arguta Planch. (Sarunashi) and A. rufa Planch. (Shima-sarunashi), indigenous Actinidia species in Japan and their interspecific hybrids

Abstract

Budbreak on 2-bud cuttings of Actinidia arguta and A. rufa, exposed to 200 hr of natural chilling below 7°C and additional chilling at 4°C was compared with that of kiwifruit, A. deliciosa and A. chinensis. A high percentage of budbreak occurred in A. arguta and A. rufa indicating that they have a very low chilling requirement, namely 200 hr, under natural conditions, whereas A. deliciosa cultivars required 600-800 hr or more of chilling; chilling requirement of A. chinensis was intermediate. Some interspecific hybrids also exhibited a low chilling requirement.