Chilling and heat requirements of peach cultivars and breeding selections

Abstract

The introduction of cultivars with lower chilling requirements is considered as a countermeasure against the northward movement of peach cultivation areas and the delay in breaking endodormancy and awakening due to the effects of global warming. In this study, we conducted a four-year survey using cuttings of cultivars and selected lines that are thought to have lower chilling requirements and clarified their chilling and heat requirements. The chilling requirements of the test plants varied from 225 to 862 for CH and from 346 to 880 for CU, both of which were lower than those of the major cultivars. ‘TropicSnow’ had 250 CH and 384 CU, and ‘Momo Daigi Tsukuba 1’ had 592 CH and 706 CU. The heat requirement ranged from 4694 to 5893 for GDH. ‘TropicSnow’ had 5278 GDH, and ‘Momo Daigi Tsukuba 1’ had 4965 GDH and tended to be lower for rootstock cultivars.