Clonal Forestry

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ATTACK OF THE CLONES Challenging new episode in
our course ! Clonal Forestry Dag Lindgren
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Clones in Nature
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Clones dominated the early flora
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• Natural cloning in conifers is rather rare
• In Scandinavian forest ecosystems clones are most
  characteristic of the understory herbaceous
  vegetation, where they can be dominant
• 3-15 genotypes in a population represents a
  typical natural situation

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Clones in culture
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Examples of Agricultural Monoclonal Successes

• Bartlett or Williams pear
• discovered 1770, 75 worldwide crop
• Red Delicious apple
• origin 1870, 50 worldwide crop
• and many many more.

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From the history of clonal forestry

• The first known use of vegetative propagation for
  forestry purposes was with Sugi (Cryptomeria
  japonica D. Don, a conifer) in Japan, where it is
  natural, in the 15th century.
• Vegetative propagation of poplars (Populus sp.)
  has a long history in Europe. Organised clonal
  forestry started in the beginning of the 20th
  century

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Examples of clonal forestry
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Eucalyptus clones in Brazil
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Eucalyptus monoclonal block mosaic in Brazil
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Some reasons for a forester to use clonal forestry

• To produce a more uniform product
• To improve the forest by using a genetically
  better planting stock
• To get customer-tailored improved material.

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A uniform product
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Improved clones have advantages over improved
seedlings!

• Little time lag between selections in the
  breeding and practical forestry
• Short time span to deploy the gain achieved by
  breeding (get bulk of improved copies)
• Flexible for variations in plant consumption
• Eliminate problems with variations in seed
  production
• Eliminate problems in reproductive output or
  reproductive phenology of trees in seed
  production unit

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Possible advantages with clonal forestry

• Eliminate selfing
• Eliminate undesired unimproved pollen
• Relatedness among selections little problem
• The market for a bred material can be small
• Tailored varieties (no costumer too small...)
• Choose the level of diversity desired (often
  uniformity)
• Mass-propagation of expensive but good seeds
• Possible to use non-additive variance (like
  hybrid effects and dominance)
• Exploit the additive genetic variation better

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Possible advantages with clonal forestry

• Choose clones which do not waist resources on sex
• Create "physiologically programmed types
• Different cloning methods offer different options
• Higher genetic gain (see above)
• Combine characteristics which seldom are combined
• Test in different environments and choose for
  wider adaptation (ecovalence)

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Comparison clone mix and seed orchard
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Other reasons

• Cuttings may be morphologically different, e.g.
  now insecticide use on conifer plants will be
  more restricted (Pyrmetrin) Cutting plants have
  thicker bark and more sturdy stem base, and are
  less harmed, and may possible constitute a
  solution. This may become the main reason for use
  of cutting Norway spruce plants in Sweden 2003.
• It may be easier to make cuttings than to get
  seeds

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Often increased costs

• More moments
• Clones must be conserved while tested
• Legal demands often multiply costs
• For many species - expensive propagation

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Restrictions for clonal forestry

• Experience over long time and large areas is
  needed, but accumulates slowly over time
• Commercial and legal problems considerable and
  larger than with seeds
• Get into problems with opinions, symbol of
  exploitation of Nature, "clone" is a dirty word
• Not so profitable in practice as it appears from
  theory

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Risks and uncertainties

• Physiological state matters
• Propagation technique may matter for result
• Storage technique. Storing genotypes while
  testing costs money and change characteristics.
• Somaclonal variations
• State of ortet may matter
• Juvenile age selection may give secondary effects
• Ecologic consequences? (probably limited)
• Specific pests and diseases may be favoured by
  some clones and that they are repeated in stands
  and even spread from them
• What happens at mature age? Often lack of mature
  field trials.

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How many clones?
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Genetic diversity in a stand is likely to favour
production

• A single genotype demands the same things at the
  same time, thus inefficient site use!
• In a mix another genotype may take over the
  ecological space left by a failed genotype.
• A disease or pest is expected to spread faster in
  a uniform crop.
• Single clones have rather high GE interaction
  thus may perform inexpectly bad under some
  conditions

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Clone number
Genetic and commercial Gains
Plantation Failure
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Too much diversity in plantations?!

• Most crop- and many forest managers do not like
  diversity
• Uniform trees means better economy and simpler
  forestry even if biological production is lost
• The genetic superiority of superior clones is
  much larger than the foreseen expected loss by
  uniformity.
• The demand for high diversity in intensively
  managed forests may be very expensive in lost
  future gain
• Uniform crops are easier to handle legally and
  commercially

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Better science possible

• Replications
• Reproducibility

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A tool for a more effective breeding!   

• Used for seed production
• Gains faster realized
• Clonal test means testing the sum of genes
  deployed, progeny testing often are confounded by
  paternal genes just contributes to noise
• A seedling is genetically unique clones can be
  optimally replicated.
• Clonal test gives in practice much information
  about ability to transfer gene to progeny
• More efficient use of the variation occurring
  after sexual propagation

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A tool for a more effective breeding!   

• The efficiency of clonal testing depends on costs
• Collaborators instead of competitors
  (non-egoistic clones)
• Test on many environments and choose for wider
  adaptation
• Test in the field and cross in the archive
• Combine wood in the field and reproduction in
  archive
• Biotechnical breeding - like transgenetic trees -
  becomes more feasible

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Clonal selection
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Phenotypic selection
Breeding value
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Comparison (at the same dimensioning) of clonal
or seedling
based testing for the Swedish Norway spruce long
term
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breeding program. Clonal testing adds around
30 to gain. (Rosvall 1999)
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Test size (plants)
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Cutting
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Green-house for cutting production
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Clones may be made from somatic embryogenes

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Acknowledgements

• Darius Danusevicius