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High and sustainable biomass production of Salix: bridging molecular genetics, ecophysiology and plant breeding
Photo: AC Wästljung
Martin WeihSLU, Dept. of Crop Production Ecology, Uppsala, Sweden
Ann-Christin Rönnberg-Wästljung (SLU)Jan Stenlid (SLU)Christer Björkman (SLU)Inger Åhman (SLU)Stig Larsson (Lantmännen Agroenergi AB)Sara von Arnold (SLU)
The Salix production system
0
6
12
18
24
Sta
ndin
g bi
omas
s (t
ha-1)
W0F0 W0F+ W+F0 W+F+
200120022003
(A)
(Source: Weih & Nordh [2005] Tree Physiol.)
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Cutting cycle for a Salix plantation
Commercial breeding of Salix in Sweden
• During 1985 a breeding program for Salix was established at SLU.
• Since 2002 Lantmännen Agroenergi AB has the responsibility for the breeding.
• Traditional breeding has increased the biomass production by c. 60%.
Goal
• The long term goal with the project is to develop breeding methods for complex traits where selection with traditional methods is difficult.
High productive
and resistant Salix clones for Sweden and Europe
Plant breeding and selection
Molecular markers
Genetics
Growth
Resistance
A combination of phenotypic and marker-based selection will speed up
the development of new varieties
• Development of genetic maps.• Analysis of phenotype and inheritance of
resistance, tolerance and growth traits as well as development of genetic markers for these traits.
• Test the markers in breeding populations.
WP3. Synthesis/discussion
WP1b. High and sustainable
biomass production
WP1c. High and sustainable resistance:
insects, rust fungi
WP1a. Genetic background for
growth and resistance
WP2. Testing and application of markers in the
breeding
WP1. Molecular breedingPlant material
Genetic linkagemaps
Field, greenhouseand lab experiments
Association phenotype -genotype
Candidate genes (Poplar genome)
Markers
Methods
Analysis of many DNA markers in parents and offspring of Salix families
Inheritance of markers is studied in the Salix families
Markers are combined into linkage groups (chromosomes) to a genetic map
Construction of a genetic mapMolecular breeding, WP1a:
Individual1
2
4
3
Marker size
Example of one type of marker analysisM456
M72107.1
M40816.6
M221724.2
Grupp II
F43325.7
M743
29.2
F209
33.6
40.3
M291851.0M14152.67556.6
F37961.9M46765.3
M34381.3
75586.4
647
88.6
624
97.9M35599.2
M191
105.7
4.8 F453
F633M607
36.1
• Microsatellites and SNPs are used as genetic markers
we have developed a SNP panel with 384 SNPs
most markers are anonymous but some are located in candidate genes for rust resistance, insect resistance and drought tolerance
• The linkage maps will be used for QTL analyses for biomass traits, rust and insect resistance, NUE and drought tolerance.
Genetic basis for resistance and biomass traitsMolecular breeding, WP1a:
Contact: Anki Rönnberg-Wästljung ([email protected])
SNP*
• We are currently working with two linkage maps in two mapping populations
(Salix viminalis x S. schwerinii) x S. viminalis - 470 individuals
S. viminalis x S. viminalis - 282 individuals
*Single nucleotide polymorphism
Development of a test protocol for improved long-term biomass growth
In perennial crops such as Salix, a pre-requisite for successful breeding is the availability of simple test methods for rapid assessments of long-term clone performance in large mapping populations.
Objective: To identify, in young plants, growth and resource economy traits that indicate long- term growth performance and that are easy to measure in mapping populations.
Field and laboratory studies in Sweden.
The final goal is to find genetic markers (QTL) for the identified phenotypic traits and to use these in marker-assisted breeding.
Molecular breeding, WP1b:
Photo: Carolyn Glynn
Can we identify growth and resource economy traits in juvenile (pot- grown) plants that indicate long-term growth performance and that are easy to measure in mapping populations?
Major challenge:
Field vs. pot studyResults: Total leaf area (yr 1, pot) was found to be a good predictor of total shoot biomass (field) after 3 years of growth if calculated genotype-specific
0 50 100 1500.0
0.5
1.0
1.5 (A) Björn
0 50 100 150
(B) Gudrun
0 50 100 1500.0
0.5
1.0
1.5
Sho
ot b
iom
ass
per s
tool
(fie
ld) (
kg)
(C) Jorr
0 50 100 150
(D) Loden
0 50 100 150 Leaf area (pot) (cm2)
0.0
0.5
1.0
1.5 (E) Tora
0 50 100 150
(F) Tordis
W0F0
W0F+W+F0
W+F+
(Source: Weih & Nordh [2005] Tree Physiol.)
Field vs. pot studyResults: 2-component regression model including shoot biomass and leaf N conc. (yr 1, pot) was found to be a more robust predictor of total shoot biomass (field) after 3 years of growth.
0.0 0.5 1.0 1.5 2.00.0
0.5
1.0
1.5
2.0
Shoot biomass field (kg)
Sho
ot b
iom
ass
mod
el (k
g)
a
0 4 8 12 16 20 240
4
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Rank of Shoot biomass field
Ran
k of
Sho
ot b
iom
ass
mod
el b
Model: SB field = a * SBpot + b * LNpot + c
R2 = 0.83 R2 = 0.85
Breeding of varieties adapted to the climate in Southern Europe
Water use efficiency and plant tolerance to high leaf temperatures are among the major breeding goals for Salix with respect to the potential markets in Southern Europe.
Objectives: To investigate the eco-physiological basis of water economy and heat tolerance, and to identify plant traits that improve water use efficiency and heat tolerance.
Field and laboratory studies in Sweden and southern Europe.
Also here, the final goal is to find genetic markers (QTL) for the identified phenotypic traits and to use these in marker-assisted breeding.
Heat damaged leaves from a plantation in Greece
Molecular breeding, WP1b:
Photo: Inger Åhman
Leaf beetles – major pests of willows
• Heavy defoliation by leaf beetles and their larvae may reduce biomass production by 40 %.
• The likelihood for outbreak densities of leaf beetles in a plantation during one rotation period (25 years) is high.
Photo: Christer Björkman
Molecular breeding, WP1c:
Leaf beetle control• Aim: to analyze the heritability of and
identify genetic markers for resistance against beetles.
• Parts of the resistance may operate directly (i.e. leaf chemistry) and indirectly through natural enemies (bent dashed arrow). Trade- offs between direct and indirect defences?
• A reliable bio-assay protocol for estimating resistance against leaf beetles was developed.
• Indications for the absence of trade-offs between direct and indirect defences against leaf beetles were found.
EnemyEnemy eggegg
EnemyEnemy
Bark removed to lay bare an egg.Illustrations: Christer Björkman
Molecular breeding, WP1c:
Rust on suceptible clones can cause production losses of up to 40%.
Improved resistance to leaf rust• For a sustainable and high production of Salix it is
important with varieties resistant towards leaf rust.
• In order to test for rust resistance, inoculation experiments using a leaf disc bioassay have been carried out on 600 individuals in two mapping populations (S. viminalis x S. schwerinii and S. viminalis x S. viminalis). Disease assessments on the same individuals were also done in field trials.
• Great variation in rust resistance components was found between individuals in both populations. The S. viminalis x S. schwerinii population showed the highest degree of variation and many individuals had a high level of resistance. The data will be used in QTL mapping of rust resistance genes as soon as the linkage maps for the two populations have been constructed.
Leaf rust caused by the fungi Melampsora larici-epitea
Photo: Berit Samils
Molecular breeding, WP1c:
Leaf disc bioassay to assess leaf rust resistance in Salix.
Testing and application of markers in practical breedingObjectives- to test various markers in different breeding material;- to test the efficiency of selection with available markers in new breeding populations;
- to organize field testing in continental Europe;- to apply markers for selection among seedlings as soon as markers become available.
Molecular breeding, WP2:
Field trials are established in Italy and Portugal;
Protocols for the introductionof molecular methods into the practical breeding are developed;
Link to an European project(BREDNET-SC).
Thank you for your attention!
Martin Weih ([email protected])Ann Christin Rönnberg-Wästljung ([email protected] Stenlid ([email protected])Christer Björkman ([email protected])Stig Larsson ([email protected])Inger Åhman ([email protected])
