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United States Department of Agriculture

Agricultural Research Service

Research Project: STONE FRUIT BREEDING AND DEVELOPMENT Title: Interactive effects of light and chilling on peach flower and leaf budbreak

Authors
item Okie, William
item Blackburn, Bryan

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 18, 2010
Publication Date: July 1, 2011
Citation: Okie, W.R., Blackburn, B. 2011. Interactive effects of light and chilling on peach flower and leaf budbreak. HortScience. 46(7):1056-1062.

Interpretive Summary: In moderate climates such as in the southeastern United States, winter chilling varies from year to year and site to site. Response to chilling temperatures is a critical factor in the suitability of peach cultivars, since it has a great effect on time of bloom, and thus the liklihood of a crop. Much of the research on chilling uses cuttings exposed to various treatments and forced under controlled conditions. Light is not generally considered an important factor in such conditions, and the effect of light has been little studied. In our tests, after chilling had been satisfied naturally, peach flower and vegetative bud break occured faster when forced in the presence of light than in darkness. Light increased both bud break rate as well as the total percentage bud break. A 24 h/day exposure was usually more effective than 2 or 12 h/day, but both were more effective than darkness. Red, yellow and fluorescent light were more effective in increasing bud break than blue, green, infra-red or incandescent light. Promotive effects of light were less when buds had received enough natural chill and heat to break within a week of forcing at 18°C.

Technical Abstract: Response to chilling temperatures is a critical factor in the suitability of peach cultivars to moderate climates such as that in the southeastern United States. Much of the research on chilling uses cuttings exposed to various treatments and forced under controlled conditions. Light is not generally considered an important factor in such conditions, and the effect of light has been little studied. In our tests, after chilling had been satisfied naturally, peach flower and vegetative bud break occured faster when forced in the presence of light than in darkness. Light increased both bud break rate as well as the total percentage bud break. A 24 h/day exposure was usually more effective than 2 or 12 h/day, but both were more effective than darkness. Red, yellow and fluorescent light were more effective in increasing bud break than blue, green, infra-red or incandescent light. Promotive effects of light were less when buds had received enough natural chill and heat to break within a week of forcing at 18°C.

Last Modified: 10/30/2014