Articles
DELAY OF FLOWER BUD PHENOLOGY OF RABBITEYE AND SOUTHERN HIGHBUSH BLUEBERRIES WITH SOYBEAN OIL AND ABSCISIC ACID
Article number
884_86
Pages
647 – 650
Language
English
Abstract
Late winter freezes are primary causes of yield reduction of rabbiteye and southern highbush blueberries.
Sprays of soybean oil in early February can delay peach bloom by up to seven days, reducing the potential of freeze damage. Legacy (Vaccinium corymbosum) blueberry plants were sprayed to runoff on 22 February with 0, 60, 90 or 120 ml/L soybean oil (Golden Natural, 93% soybean oil a.i.). Flower bud abortion was evaluated on 21 March.
Flower bud phenology was rated periodically until first bloom, then percentage of open bloom was rated every 2 to 3 days.
Fruit were harvested for yield, and 50-berry samples were taken to determine berry size.
Sprays of 60, 90 and 120 ml/L soybean oil delayed the 50% open bloom date of Legacy by 2, 4, and 9 days, respectively, but caused 9, 35 and 87% mortality of flower buds.
Berry size was increased by 14 to 23% by oil sprays. Climax (V. ashei) blueberries were sprayed to runoff on 4 March with water, 50 ml/L TNsoy14 (96% soybean oil, a.i.), 1000 mg/L 30025 (lab number) synthetic abscisic acid (ABA Valent BioSciences Corp.), or the combination of TNsoy14 and ABA. The ABA was dissolved with ethyl alcohol, stored in the dark until use and mixed in the spray tank in the field.
The ABA was applied with 5 ml/L Tween 20 as an adjuvant.
Spraying 50 ml/L TNsoy14 or 500 mg/L ABA delayed the 50% open bloom date by 1 day, and the combination of the two delayed bloom by an additional day.
The 50 ml/L oil, 1000 mg/L ABA, and the oil plus ABA treatments did not significantly affect crop load or berry size.
Sprays of soybean oil in early February can delay peach bloom by up to seven days, reducing the potential of freeze damage. Legacy (Vaccinium corymbosum) blueberry plants were sprayed to runoff on 22 February with 0, 60, 90 or 120 ml/L soybean oil (Golden Natural, 93% soybean oil a.i.). Flower bud abortion was evaluated on 21 March.
Flower bud phenology was rated periodically until first bloom, then percentage of open bloom was rated every 2 to 3 days.
Fruit were harvested for yield, and 50-berry samples were taken to determine berry size.
Sprays of 60, 90 and 120 ml/L soybean oil delayed the 50% open bloom date of Legacy by 2, 4, and 9 days, respectively, but caused 9, 35 and 87% mortality of flower buds.
Berry size was increased by 14 to 23% by oil sprays. Climax (V. ashei) blueberries were sprayed to runoff on 4 March with water, 50 ml/L TNsoy14 (96% soybean oil, a.i.), 1000 mg/L 30025 (lab number) synthetic abscisic acid (ABA Valent BioSciences Corp.), or the combination of TNsoy14 and ABA. The ABA was dissolved with ethyl alcohol, stored in the dark until use and mixed in the spray tank in the field.
The ABA was applied with 5 ml/L Tween 20 as an adjuvant.
Spraying 50 ml/L TNsoy14 or 500 mg/L ABA delayed the 50% open bloom date by 1 day, and the combination of the two delayed bloom by an additional day.
The 50 ml/L oil, 1000 mg/L ABA, and the oil plus ABA treatments did not significantly affect crop load or berry size.
Authors
C.E. Sams, D.E. Deyton, J.C. Cummins, J.R. Ballington
Keywords
bloom delay, fruit thinning, ABA
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