improving knowledge on tree architecture to improve...

APPLE AND PEAR TREE ARCHITECTURE A WAY TO IMPROVE ORCHARD MANAGEMENT

Lauri, PÉ

[email protected]

INRA, Joint Research Unit SYSTEM (Tropical and Mediterranean Cropping System

Functioning and Management), 34060 Montpellier, France KEYWORDS apple, architectural type, bourse-over-bourse, branching, centrifugal training system, flowering spur desynchronization, extinction, fruiting, pear, pruning, return-bloom, salsa training system, vegetative growth ABSTRACT Between 1960 and 1970, tree architecture evolved as a scientific discipline in tropical forests. First to synthetize knowledge on the form of trees and how it develops with time (ontogenesis), and second to analyze relationships between tree development and the dynamics of forests (sylvigenesis). Since 1989, the idea was developed at INRA, France, to implement architectural concepts on fruit trees with the objectives to analyze genetic diversity and to improve training and pruning. According to Lespinasse’s typology, apple trees can be classified between two extreme types: “type I” (columnar type and spur type) cultivars, characterized by upright scaffold branches with dense spur branching, lateral fruiting and alternate bearing, and “type IV” cultivars with pendant laterals, long fruiting shoots, terminal fruiting and more regular bearing. Our objectives were to get more insights into these tree forms, and especially to analyze the relationships between vegetative growth and fruiting patterns. The first quantitative works were done on fruiting branches with cultivars of contrasting architectures.

Figure 1 : Relationships between the number of leaves of flowering shoots (bourse and bourse-shoot) on 1YW and flowering (top; from Lauri and Trottier, 2004) and fruiting (bottom) frequency in terminal position on that shoot on 2YW, for 2 apple cultivars, ‘Pitchounette’ and ‘Chantecler’. Each symbol represents frequency on at least five shoots. Source: Lauri & Corelli-Grappadelli 2014

The methodology included the description of the fate and growth of all laterals across consecutive years. We showed that each cultivar can be characterized by a combination of architectural traits defining its endogenous architectural strategy. Especially, two main traits have been seen: bourse-over-bourse (the ability to string fruiting on a same shoot over consecutive years) and extinction (the death of a shoot). Across genotypes, bourse-over-bourse is curvilinearly related to shoot length (Figure 1). There is also a positive relationship between bourse-over-bourse and extinction supporting the idea that a higher ability to differentiate a flower bud in terminal position on a bourse-shoot is somehow related to a lower spur density on the branch due to extinction. The talk will explain how these findings opened to the concept that implementing artificial spur extinction in the ON-year on cultivars prone to alternate bearing is efficient to improve regular bearing. This technique has been initially developed on the ‘Centrifugal Training System’ where it also aimed at improving the light climate for a better leaf functioning and fruit coloring (Figure 2).

Based on results obtained in commercial orchards we are now progressing towards less-demanding training and pruning systems. We consider that the search for both canopy porosity (partly related to natural or artificial extinction) and the physiological autonomy of the fruiting shoot (partly related to its length; see above) should be the objectives of manipulations done on the apple tree to improve regularity of bearing and fruit quality. Moreover, we propose to better adapt training to the natural ability of a given cultivar to be trained with a single trunk or

as multiple-reiterative trunks. This latter concept is implemented in the ‘Salsa Training System’ (Figure 2). Our experience in pear is strongly inspired by what was developed in apple. The talk will focus on two aspects, the influence on the entrance into production of the type of branching on the trunk in the first two years in the orchard, and the interest of artificial spur extinction of the vegetative shoots in the OFF-year.

Figure 2: Evolution of tree architecture

APPLE AND PEAR TREE ARCHITECTURE A WAY TO IMPROVE ORCHARD MANAGEMENT

P.É. Lauri - INRA

Montpellier, FranceJoint Research Unit SYSTEM (Tropical and Mediterranean Cropping System Functioning

and Management)

2015 WSU Fruit School - Apple and Pear Horticulture

Montpellier

Architectural concepts

Interest for apple: from knowledge to practice

Training and pruning the apple in France:a brief history and where we are now

Pear architecture

Architectural concepts

Plant development is driven by endogenousprocesses, modulated by the environment

Hallé (F), Oldeman (NL), Tomlinson (USA), 1978

tree architecture↕

forestry and sylvigenesis

Botanic: Bell 2008; Barthélémy & Caraglio 2007Fruit-trees: Lauri 2002; Lauri & Laurens, 2005; Costes, Lauri & Regnard 2006

Architecture - Knowledge to practice - Training & pruning the apple – Pear architecture

Architecture - Knowledge to practice - Training & pruning the apple – Pear architecture

1 – Qualitative criteria

Position of flowers on scaffold branches (lateral vs. terminal)

Peach – Prunus persica

Horse chesnut –

Aesculus hippocastanum

Architecture - Knowledge to practice - Training & pruning the apple - Pear architecture

2 – Architectural models: 22The observed branch framework may be adequately described by a

single model.

e.g., cherry conforms to Rauh's model.

(Hallé et al. 1978)


The observed branch framework of other species may be

described by at least two models.

e.g., apple partly conforms to Rauh's

Main architectural features of the Apple tree:

1 - All branches initially orthotropic (upright trunk and branches). Secondary bending usually occurs with fruit load.

2 - Branching: rhythmic.

3 - Flowering: lateral and terminal.

Terminal flowering is typical of Scarrone's model.

5-year-old ‘Starkrimson’ tree / M7


Scarrone's model.


(Hallé et al. 1978)

High frequency

of lateral

flowering

« RAUH

Tendency »

Alternate

bearing

High frequency

of terminal

flowering

« SCARRONE

Tendency »

Regular

bearing


‘Starkrimson’ / M7 (5YO) ‘Granny Smith’ / M7 (3YO)

(Lespinasse & Delort, 1986)


Columnar type

Effects of the environment!

e.g., cold winter winter chilling acrotony

mild winter lack of winter chilling basitony


Typical conditions in

Southern Brazil

(Schmitz et al. 2014, 2015, 2015)

3 – ReiterationThe architectural sequence is reiterated WITHIN tree crown


Larch –

Larix decidua

Total reiteration

Crown shyness-Partial reiteration

Heading cut

Apple - ‘Galaxy’

Bending

Pear - ‘Bartlett’

Ficus benjamina

Total reiteration

& Cocos nucifera

No reiteration

Reiteration is an important phenomenon in fruit tree

e.g., Apple

1 – The relationship between reiteration and flowering depends

on the cultivar.

‘Granny Smith’‘Starkrimson’

Strong growth No flowering

= antagonism betweenvegetative growthand flowering

Strong growth Flowering

= no antagonism betweenvegetative growth

and flowering


Reiteration is an important phenomenon in fruit tree

2 – Granny Smith: growth strategy includes growth fruiting

in terminal position bending reiteration growth etc. (8-

year sequence on M7)


Architectural concepts (criteria, models, reiteration)

Interest for apple and pear: fromknowledge to practice

Training and pruning the apple in France: a brief history and where we are now

Pear architecture


Year 1

…

Fruit-tree = « black box »

Concepts of plant architecture to develop a methodology

to analyze vegetative growth and fruiting patterns

2 steps

16


Year 2

Year 3

1 - Branch growth over consecutive years

Latent - L

Extinction = death of a lateral

(often after F or A)

2 – Type of laterals

17


Vegetative - V

- F

- A

Interest of the methodology: a posteriori analysis of branching and

fruiting over several years

Sequence of laterals (filiation)

Genotypic differences on two main traits: bourse-over-bourse &

extinction

18


&

1st aspect: ability to string bourse-over-bourse

‘Granny Smith’

‘Gala’

3-year-old spurs with

contrasted fruiting patterns

AA

A

A

V

A

Bourse


Bourse-shoot

‘Chantecler’ & ‘Pitchounette’: parabolic

relation

Fruit-set is dependent on the number

of leaves/leaf area established in the

previous year

= « flower quality » or « floral strength »

in terms of the aptitude to set fruit

NB: same relationship in Mango (Normand

et al. 2009) and in forest trees

Fruit-seti.e., at least one fruit developed

y = -0.002x2 + 0.084x + 0.008

R2 = 0.54

y = -0.001x2 + 0.06x - 0.16

R2 = 0.77

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 3 6 9 12 15 18 21 24 27 30

Number of leaves of shoots (bourse & bourse-shoot) on IYW

Fru

itin

g in

te

rm.

Po

s.

on

2Y

W (

rel. f

req

.

ou

t o

f a

ll f

low

. sh

oo

ts)

Pitchounette

Chantecler


(Lauri & Corelli-Grappadelli 2014)

Subtending shoot (year N)

Fruit-set (year N+1)

‘Starkrimson’/M7

Bourse-over-bourse =

localized process

What about all spurs on a

branch or a tree?

Spur-type trees have an

alternate bearing on low-vigor

rootstocks (e.g. M9) and a

more regular bearing pattern

on more vigorous rootstocks

(e.g. M7).

desynchronization

synchronization vs. desynchronizationArchitecture - Knowledge to practice - Training & pruning the apple - Pear architecture


(Lauri & Laurens 2005)

synchronization vs. desynchronization

Apple - ‘Braeburn’: case of synchronization

Pear – ‘Angélys’:

case of desynchronization


synchronization vs. desynchronization

Physiological mechanisms?

Relations with hydraulics

(Han et al., 2007; Lauri et al., 2008)

2nd aspect: spur extinction


3rd aspect: bourse-over-bourse extinction

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1Bourse over bourse (frequency)

exti

nct

ion

(fr

eq

ue

ncy

)

Granny Smith

Red Winter

Jonagold

Royal GalaMelrose

R. des Reinettes

O. Spur

Delicious

Fuji

Braeburn

TYPE IV

TYPE II

Golden Delicious(Lauri et al., 1995,

1997, … 2014)


Each cultivar has its own architectural strategy related to the bearing pattern (bourse-over-bourse, extinction, de/synchronization,

latency, shoot length…)

Suggest a negativerelationship between spurdensity and bourse-over-bourse.

Idea to do « artificial spurextinction » on cultivars with low bourse-over-bourse.


NB: flower/fruitlet thinning vs. artificial spur extinction

Artificial extinction, especially on flowering

spurs (…; Tustin et al.; van Hooijdonk et al.)

Flower or fruitlet thinning

(… Kon et al. 2013)

Branch Gauge to

objectively balance

the nb of fruits / cm²

of fruiting branch

cross-section area





Pear architecture


‘Pink Lady’ – 5-6 year-old trees.

An obvious effect of training and pruning strategies on fruiting

Challenge: how to use the knowledge on tree architecture to establish rulesfor training and pruning…


Phenotype: native tree architecture responses to manipulations

Paradigm: « trunk – fruiting branch - fruiting spur »


Vertical Axis(Lespinasse 1977,

1980)

Solaxe(Lespinasse &

Lauri 1996)

CentrifugalTraining

(Lauri 2009)

Salsa(Lauri et al. IHC 2014)

Paradigm: « reiterative trunk–

fruiting spur »


‘Braeburn’/M7- 9YO (INRA) ‘Granny Smith’/M7- 3YO (INRA)

Strong variations of branching depending on the cultivar (especially immediate branching in the 1st year of planting)

‘Braeburn’: well adapted to a cylindrical shape, Centrifugal Training

‘Granny Smith’: interest to use ALL reiterative trunks

Basic principles To improve leaf functioning + return-bloom + fruit quality (color…)

Canopy Porosity & Fruiting Shoot Autonomy

Single vertical trunk:

need to partition the vigor towards fruiting shoot

trunk fruiting branch fruiting shoot

2 or more reiterative trunks:

less vigourous than a single trunk

reiterative trunk fruiting shoot

satisfactory yield quantity and quality

lower labour inputs, due to less time for training and pruning to shape the tree.


y = -0.002x2 + 0.084x + 0.008

R2 = 0.54

y = -0.001x2 + 0.06x - 0.16

R2 = 0.77

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 3 6 9 12 15 18 21 24 27 30

Number of leaves of shoots (bourse & bourse-shoot) on IYW

Fru

itin

g in

te

rm.

Po

s.

on

2Y

W (

rel. f

req

.

ou

t o

f a

ll f

low

. sh

oo

ts)

Pitchounette

Chantecler




Pear architecture


Tree scale: different types of laterals along the main axes, immediate / delayed laterals (IL/DL)

0

5

10

15

20

25

30

35

40

45

‘Angélys’ ‘Conférence’ ‘D. comice’ ‘Williams’

Me

an

nb

of

late

rals

c b a a cc b a

1st year 2nd year


Pear architecture studies and training and pruning: greatlyinspired from progresses in apple

1st year - Immediate

2nd year - Delayed

(Lauri et al., 2002)

R2

= 0.912

0

20

40

60

80

100

120

140

160

-0.2 0 0.2 0.4 0.6 0.8

Differential in IL : (IL-DL)/(IL+DL)

WilliamsHarrow Sweet

Delwilmor

P. Crassane

HW608

Abbé Fetel

D. Comice

Conférence AngélysMea

n n

b o

f fl

ow

er

clu

ste

r

Tree scale: high immediate branching vs. delayedbranching high flowering


(Costes et al., 2004)

Interest of SALSA-type trees

Branch scale: flowering – synchronization vs. desynchronizationThe examples of ‘Doyenne du Comice’ and ‘Angélys ’


‘D du Comice’: high synchronization of flowering Low fruit-set (competitions) Low productivity

’Angélys’: desynchronization of flowering from3YW onwardsMore regular bearing

Training and pruning pear


As for apple, a main issue is to decrease spur density especiallyon high flowering cultivars

Usual training systems cannotsolve this problem

NB: chemical thinning only recently allowed in France (benzyladénine (Maxcel –Exillis), NAA (Rhodofix), métamitrone (Brévis))

Training and pruning pear – Experiment on ‘Guyot’ to decreasealternate bearing: artificial extinction on vegetative spurs in OFF year


(Florens et al., 2014)

Heading cuts &

chemical thinning

Vegetative Spur Extinction &

chemical thinning

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