Post on 11-Feb-2017
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