Slide 1
Al Kovaleski
February, 2014Summer pruning southern highbush blueberries in FloridaUniversity of FloridaHorticultural Sciences Department1Blueberry summer pruning2No removal of flower buds Long growing season in FL Pruning promotes increased vigor More support for reproductive structuresObjectives3Determine the effects of timing and severity of summer pruning:
Vegetative traits: Regrowth Cane breakage Timing of defoliation Incidence of leaf spots Incidence and severity of stem blightReproductive traits: Flower bud initiation Fruit set Yield Quality of fruitPlant material4Two cultivarsEmerald and JewelSeven year old plantsCommercial cultural practicesPSREU Citra, FL
Treatments5No summer pruning controlPrune 30% early JunePrune 30% mid-JulyPrune 30% early June+tipPrune 60% early June+tipDetailed hand pruning control
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Treatments6
30%60%UnprunedVegetative traits7Canopy volumeRegrowthCondition of fall foliageTime of defoliationLeaf spot
Vegetative traits8Incidence and severity of Stem Blight
Reproductive traits9Re-growth shoots collected to assess timing of flower bud initiation Late summer until defoliationReproductive traits10HarvestPeriodYieldFruit qualityTotal soluble solidsTitratable acidityFirmnessAverage berry weight
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Labmate-online.comResults to date11Regrowth volume - Jewel12
Cane breakage - Freezes13
Leaf spots - Jewel14
Environmental Conditions152011201220132014Leaf spots - Jewel16
Defoliation - Jewel17
No significant defoliation in Emerald until December17Flower bud initiation18
Flower bud initiation19
Flower bud initiation20Emerald Sep 8thJewel Oct 20thFlower bud initiation21 Important:Develop management strategies to enhance floweringRegulate fruit load
Yield!
First sign of transition detectableStem blight22Jewel was not affected
No differences among treatments in Emerald25% incidenceBerry quality23Average weight - JewelReduction in the 60%+tip1.9g 1.4gOthers averaged 1.7g
pH, acid and sugar content, anthocyanins, firmnessNo differences
24Yield - Emerald
Yield - Jewel25Yield - Jewel26
Acknowledgements27Dr. Darnell and Dr. WilliamsonDr. Olmstead and Dr. Harmon
28
Thank you!
TreatmentLeaves containing at least one leaf spot (%)
2011---17 Nov1 Dec21 Dec
Non-pruned---70.0ax70.0a56.7ab
Hand-pruned---33.3b16.7b53.3ab
30% June---43.3ab40.0ab50.0b
30% June+tip---36.7b40.0ab63.3ab
60% June+tip---36.7b43.3ab83.3a
30% July---66.7a73.3a66.7ab
2012--25 Oct8 Nov23 Nov11 Dec
Non-pruned--38.3a81.7a88.3a97.5a
Hand-pruned--31.7ab56.7b78.3ab96.7a
30% June--35.0a61.7ab83.3ab95.0a
30% June+tip--26.7ab53.3b81.7ab96.7a
60% June+tip--15.0b53.3b73.3b100.0a
30% July--15.8b41.7b78.3ab94.2a
20133 Oct17 Oct31 Oct14 Nov29 Nov12 Dec
Non-pruned63.3a95.0a99.2a100.0a100.0a100.0a
Hand-pruned45.0ab82.8ab92.5ab98.3ab100.0a100.0a
30% June24.2c68.3b88.3b91.7c100.0a100.0a
30% June+tip26.7bc78.3ab90.8b95.0bc100.0a100.0a
60% June+tip23.3c66.7b86.7b92.5c100.0a100.0a
30% July32.5bc73.3ab90.0b94.2bc100.0a100.0a
TreatmentDefoliation (%)
Early OctMid OctLate OctMid NovLate NovMid Dec
Non-pruned27.5a47.5a42.1a47.5a55.0a66.9a
Hand-pruned12.5b29.2ab23.3b31.3b27.2bc56.1ab
30% June7.5b14.2b20.4b19.2bc26.7bc51.1b
30% June+tip7.5b20.0b20.8b22.5bc28.3bc57.2ab
60% June+tip6.7b13.3b12.9b13.8c18.6c53.3b
30% July11.7b24.2ab21.3b25.8bc35.0b61.7ab