Effect of timing and intensity of summer pruning on vegetative and

January 14, 2018 | Author: Anonymous | Category: Science, Health Science, Pediatrics
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University of Florida Horticultural Sciences Department

Effect of timing and intensity of summer pruning on vegetative and reproductive traits of southern highbush blueberry Al Kovaleski September, 2013

Blueberry summer pruning  No removal of flower buds

 Long growing season in FL  Pruning promotes increased vigor  More support for reproductive

structures 2

Objectives Determine the effects of timing and severity of summer pruning: Vegetative traits: • Plant volume • Regrowth • Timing of defoliation • Incidence of leaf spots • Incidence and severity of stem blight

Reproductive traits: • Flower bud initiation • Fruit set • Yield • Quality of fruit

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Plant material  Two cultivars  ‘Emerald’ and ‘Jewel’

 Six year old plants  Commercial cultural

practices  PSREU – Citra, FL 4

Treatments  No summer pruning control  Prune 30% early June  Prune 30% mid-July  Prune 30% early June+tip  Prune 60% early June+tip  Detailed hand pruning control www.caes.uga.edu 5

Treatments Unpruned

30%

60%

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Vegetative traits  Canopy volume  Regrowth

 Condition of fall foliage  Time of defoliation

 Leaf spot 7

Vegetative traits  Incidence and severity

of Stem Blight

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Reproductive traits  Re-growth shoots collected to assess timing

of flower bud initiation – Late summer until defoliation

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Reproductive traits  Harvest  Period  Yield

 Fruit quality  Total soluble solids

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 Titratable acidity  Firmness  Average berry weight

Labmate-online.com

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RESULTS TO DATE

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Canopy volume - Emerald

Treatment Non-pruned Hand pruned 30% June 30% June+tip 60% June+tip 30% July

Winter volume (m3) 1.26a 1.06b 1.01bc 0.91c 0.68d 0.91c

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Regrowth volume - Emerald

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Flower bud initiation  Important to:  Develop management strategies to enhance

flowering  Regulate fruit load  First sign of transition detectable

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Flower bud initiation

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Flower bud initiation

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Flower bud initiation  No differences between treatments  Emerald – Sep 8th

 Jewel – Oct 20th

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Leaf spots - Jewel Leaf spot incidence (%) 2011 Treatment

2012

17 Nov

1 Dec

21 Dec

25 Oct

8 Nov

23 Nov

11 Dec

Non-pruned

70.0 a

78.8 a

57.6 ab

38.3 a

81.7 a

88.3 a

97.5

Hand pruned

33.3 b

25.4 b

54.3 ab

31.7 a

56.7 bc

78.3 bc

96.7

30% June

43.3 ab

48.8 ab

50.9 b

35.0 a

61.7 b

83.3 ab

95.0

30% June+tip

36.7 b

48.8 ab

64.3 ab

26.7 ab

53.3 bc

81.7 abc 96.7

60% June+tip

36.7 b

52.1 ab

84.3 a

15.0 b

53.3 bc

73.3 c

100.0

30% July

66.7 a

82.1 a

67.6 ab

15.8 b

41.7 c

78.3 bc

94.2 18

Defoliation - Jewel Defoliation (%) 2011 Treatmentz

2012

1 Dec

21 Dec

25 Oct

8 Nov

23 Nov

11 Dec

Non-pruned

15.0 aby

37.4 ab

21.7 a

27.5 a

68.3 a

95.0 a

Hand pruned

0.0 c

30.8 b

4.2 ab

13.3 b

31.7 b

80.0 abc

30% June

6.7 bc

27.4 b

10.0 ab

10.0 b

36.7 b

81.6 abc

30% June+tip

5.0 bc

34.1 ab

6.7 ab

11.7 b

36.7 b

86.6 ab

60% June+tip

5.0 bc

52.4 a

0.0 b

6.7 b

25.0 b

71.6 c

50.8 a

4.2 ab

13.3 b

35.0 b

80.0 bc

30% July

20.0 a

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Stem blight  Jewel was not affected  No differences among treatments in

Emerald

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Berry quality  Average weight - Jewel  Reduction in the 60%+tip  2g  1.5g  Others averaged 1.7g

 pH, acid and sugar content, anthocyanins,

firmness  No differences

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Yield - Emerald

Treatment

Yield (lbs) Periods 2 3

Total

1

4

Non-pruned

14.4 NS

5.0 a

6.2 NS

2.2 NS

0.7 NS

Hand pruned

13.4

3.7 ab

6.4

3.4

1.1

30% June

12.6

3.1 ab

6.8

3.4

0.7

30% June+tip

14.6

3.7 ab

6.9

3.2

0.6

60% June+tip

12.6

1.5 b

5.5

3.6

1.1

30% July

13.1

2.0 b

5.3

2.4

1.0

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Yield - Jewel

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Yield - Jewel

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Acknowledgements  Dr. Darnell and Dr. Williamson  Dr. Olmstead and Dr. Harmon

Florida Department of Agriculture and Consumer Services 25

Thank you!

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