ARS | Publication request: Natural and Artificial Chilling of Southern Highbush Blueberry

Submitted to: HortScience
Publication Type: Abstract
Publication Acceptance Date: May 15, 2004
Publication Date: July 16, 2004
Citation: Marshall, D.A., Stringer, S.J., Spiers, J.M. 2004. Natural and artifical chilling of southern highbush blueberry [abstract]. HortScience. 39(4):825.

Technical Abstract: A study was initiated in November, 2002 to determine the effects of exposing two southern highbush blueberries (Vaccinium corybosum L) to artificial chilling hours on initiation of bud break and advancement of floral and vegetative bud maturity. Plants of 'Jubilee' and 'Misty' were divided into 2 groups in which one was left outdoors, allowing chilling to occur and accumulate naturally, while the other group was placed in a growth chamber set as a constant artificial temperature of 4 degree C. Five plants of each cultivar were then placed into a heated greenhouse after 0, 200, 400, 600, or 800 hours of chilling (total hours of exposure to less than 5 degree C) had accumulated for forcing of flower bud development. The progression of floral bud development of the terminal three buds on five tagged stems was observed at 7 to 10 day intervals for 30 days. At the end of the forcing period observations were also made on total percent vegetative and floral bud break. Prior to accumulating sufficient chilling requirements, chilling delivery method did not appear to influence the rate of floral bud development since none advanced past stage 3 regardless of chilling regime used. However after chilling requirements were met, flower buds of plants that were allowed to chill naturally developed more quickly than did those chilled by artificial means.