Factors that affect fruitfulness and budbreak of cane-pruned vines

Matthew FidelibusViticulture and Enology, UC Davis

Kearney Agricultural Center, Parlier, CA

Presentation outline

• The annual cycle of vine growth & how it affects yield components

• Case study on the effects of node position on budbreak, fruitfulness, and fruit quality

• Causes of “blind” buds on cane pruned vines• Practices that promote budbreak and shoot

uniformity on canes

Yield Components

• Clusters per vine• Berries per cluster• Berry weight• Sugar per berry (raisin)

Reproductive cycle

• Two-year process• Year 1: Flower clusters are initiated and partially developed on microscopic shoots within buds on green growing shoots.

• Year 2: The pre-formed microscopic shoots emerge from dormant buds, flowers fully develop, and bloom, fruit set, berry growth and maturation occur.

YEAR 1

YEAR 2

- in the developing primary bud

- on the shoot

Clusterinitiation

Rachiselongation,

flowerinitiation

Flower partdifferentiation

Bloom

Pollination&

fertilizationBerryset

Berry softening

Harvest

YEAR 1

Compound Bud

Lateral (prompt) buds grow out theyear they are formed, resulting inlateral shoots

The dormant bud arises from the most basal node of a lateral shoot. Within the dormant node, an anlage develops into a shoot, tendril or cluster primordia in the spring.

Anlage Apex Leaf primordia

Earliest indication of a cluster

Compound Bud

By winter, the number of clusters eachshoot will bear in the spring has been set

Fall or winter bud dissections

Bud

frui

tfuln

ess

(%)

Time

BloomBerry set

Veraison

Sunlight promotes cluster initiation and development, and bud survival

• The number and potential size of clusters on preformed shoots is positively correlated with temperature, light, and carbohydrate accumulation in early summer, when clusters are initiated.

• Shading reduces cluster number and potential size, and promotes bud necrosis (death).

• Pruning: sun canes vs shade canes

IKI stainingcourtesy Jason Smith

NSW Australia

YEAR 2

Clusters initiated last spring will complete their growth this spring, as the preformed shoots emerge from the dormant nodes and growth to full size.

During this time cluster development can be directly affected by weather, insects, nutrition, and other factors.

Pollination

The number of berries/cluster and berry size will depend in part on pollination success. Grapes do not require insect pollination, but poor weather and mineral nutrient imbalances can substantially reduce set.

Zn application suggested2 weeks prior to bloom

Node position affects shoot emergence and fruitfulness

Cane length & node position affect yield components; raisin grape example

Node position

5 10 15 20

Nod

es w

ith s

hoot

s (%

)

20

40

60

80

100

15 node canes20 node canes

A Node position

5 10 15 20

Nod

es w

ith s

hoot

s (%

)

0

20

40

60

80

100

15-node canes20-node canes

B

Node position

5 10 15 20

Nod

es w

ith s

hoot

s (%

)

0

20

40

60

80

100

15-node canes20-node canes

C Node position

5 10 15 20

Nod

es w

ith s

hoot

s (%

)

0

20

40

60

80

100

15-node canes20-node canes

D

% Nodes with shoots

Node position

5 10 15 20

Clu

ster

s pe

r nod

e (n

o)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

15-node canes20-node canes

A Node position

5 10 15 20

Clu

ster

s pe

r nod

e (n

o.)

0.0

0.5

1.0

1.5

2.0

2.5

15-node canes20-node canes

B

Node position

5 10 15 20

Clu

ster

s pe

r nod

e (n

o.)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

15-node canes20-node canes

C Node position

5 10 15 20

Clu

ster

s pe

r nod

e (%

)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

15-node canes20-node canes

D

Number of clusters per node

Node position

5 10 15 20

Clu

ster

wei

ght (

kg)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

15-node canes20-node canes

A Node position

5 10 15 20

Clu

ster

wei

ght (

kg)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

15-node canes20-node canes

B

Node position

5 10 15 20

Clu

ster

wei

ght (

kg)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

15-node canes20-node canes

C Node position

5 10 15 20

Clu

ster

wei

ght (

kg)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

15-node canes20-node canes

D

Cluster weight (kg)

Node position

5 10 15 20

Sol

uble

sol

ids

(Brix

)

19

20

21

22

23

24

25

26

27

15-node cane20-node cane

A Node position

5 10 15 20

Sol

uble

sol

ids

(Brix

)

18

19

20

21

22

23

24

25

26

15-node canes20-node canes

B

Node position

5 10 15 20

Sol

uble

sol

ids

(Brix

)

16

18

20

22

24

26

15-node canesCol 3 vs Col 4

C Node position

5 10 15 20

Sol

uble

sol

ids

(Brix

)

18.5

19.0

19.5

20.0

20.5

21.0

21.5

22.0

22.5

15-node canes20-node canes

D

Brix

Average length of 15-node canes

DOVine

Thompson Seedless

Fiesta

Selma Pete

Feet

Some causes of blind buds on canes

• Cane length and node position (apical dominance, correlative inhibition, trunk proximity)

• Insufficient vine capacity (too many nodes left after pruning)

• Insufficient winter chill• Overcropping, excessive water deficit stress,

and/or excessive shading, in previous season

End-point principle

Trunk proximity principle (TPP)

Highest point principal (HPP)

Root-shoot principle

Chilling hours• Chilling promotes dormancy release, but

requirement is relatively low; 50 to 400 hours < 45 F

• Can be difficult to determine if poor budbreak due to inadequate chill or correlative inhibition

• “…poor budburst in the mid-cane section of cane-pruned vines in cool maritime climates commonly attributed to lack of chill may be due to apical dominance”—The Grapevine, Iland et al., 2011

Historical accumulated chill hoursNovember 1 through February 28/29

Hours < 45 F Hours >32 F and <45 F

• Dormancy-breaking agents (e.g. Hydrogen cyanamide)

• Arching or “cracking” canes• Conservative cropping & pruning• Late season and postharvest irrigation• Canopy management (sunlight exposure

decreases bud necrosis, increases bud fruitfulness)

Improving budbreak

• Funding from the California Raisin Marketing Board

• L. Peter Christensen, Mike Moriyama, Steve Vasquez, several private growers

Acknowledgements

• http://www.slideshare.net/viticulture• mwfidelibus@ucdavis.edu• Twitter: @grapetweets

Further information