Traditional breeding: no risks

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Traditional breedingno risks?

• Bert Visser
• Copenhagen, 13 december 2005

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Scope of this presentation

• definitions
• technical risks undesirable traits
• toxic compounds
• allergies
• agronomic traits
• institutional risks market demands
• the rat race for resistance
• narrowing the genetic base
• external input demands
• lack of public funding

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A matter of definition (1)

• traditional breeding juxtaposed to GM technology
• traditional breeding involves making (wide)
  sexual crosses and selecting amongst the progeny
• distinction based on crossing natural species
  barriers, not on use of modern technology

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A matter of definition (2)

• current traditional breeding relies heavily on
  modern and ultramodern technology and tools
• mapping of quantitative trait loci (e.g. yield)
• wide crosses and advanced backcrossings
• protoplast fusion and embryo rescue
• use of near-isogenic lines
• marker assisted selection
• comparative genetics
• identification of expressed sequences

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A matter of definition (3)

• definition based on current legislation
• definition of traditional breeding excludes
  transfer of genes with GM technology that may
  also be introduced traditionally
• not identical to consensus in organic agriculture

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Toxic compounds a well-known example (1)

• glycoalkaloids
• secondary plant metabolites (steroids)
• 20 different types in potato and tomato, over 300
  in other Solanaceae (also pepper, eggplant,
  tobacco)
• produced in bio-active parts of the plant
  (flowers, young leaves, sprouts, tubers)
• all potato cultivars contain glycoalkaloids
• offer protection against fungi, insect pests,
  herbivores

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Toxic compounds a well-known example (2)

• glycoalkaloids
• toxic effects include cell membrane disruption
  and inhibition of acetylcholinesterase
• symptoms gastro-intestinal effects and systemic
  effects
• intoxication reported in human volunteer study
  (Mensinga et al., 2005)

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Toxic compounds a well-known example (3)

• breeding
• in Sweden the potato Magnum Bonum was banned
  (late 1980s) (Hellenas et al., 1995)
• earlier, Lenape and Berita (released cultivars
  Australia) showed unsafe levels (Morris
  Petermann, 1985)
• substantial levels present in eggplant
  (Blankemeijer et al., 1998)
• green tomatoes and tomato leaves exhibit high
  glycoalkaloid contents (Friedman, 2002)
• different forms show different effects on humans

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Toxic compounds a controversial example (1)

• glucosinolates
• reported to induce enzymes protecting against
  carcinogens
• high levels present in young broccoli sprouts
  (Fahey et al., 1997)
• exclusively positive role contested, also
  involvement in carcinogenesis suggested (Donma
  Donma, 2005)

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Toxic compounds a controversial example (2)

• glucosinolates
• absence in rapeseed (00) increases attractiveness
  for wild animals results in bloating upon
  feeding by these animals (De Nijs, pers. comm.)

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Toxic compounds wild relatives

• wild relatives may introduce toxic compounds
• since long removed from or reduced in
  domesticated species
• offer functional protection in wild relatives
• may be linked to introgressed traits for which
  breeder selects
• incidental occurrence another possibility

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Allergies an example

• linear furanocoumarins
• plant secondary metabolites
• ancient use for treatment against skin disorders
• occur in a number of crop families
• exhibit bacterial and fungal toxicity
• concentrations in mature outer and inner petiole
  leaves of celery exceed no-effect levels
• outbreaks among workers reported (Diawara et al.,
  1995)

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Allergies among human subpopulations

• apple allergy
• oral allergy syndrome
• mucosa of lips, tongue and throat
• wheat allergy
• gluten intolerance
• common features
• small fractions of population
• immune response
• different levels in different varieties
• treated by diet adjustments

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Undesirable agronomic traits

• oil palm
• after in vitro multiplication new oil palm trees
  showed no flowering, hence no fruits, no oil
• Malaysian plantation programme
• reason unknown
• obviously flowering trait no longer expressed
• major economic costs involved

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Institutional risks

• resistance rat race
• genes for genes
• narrowing of the genetic base
• crop vulnerability
• external input demands
• environmental and socio-economic sustainability
• lack of public funding
• neglected and underutilized crops
• decreasing access to technology

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Resistance rat race

• continuous race for new resistance genes
• gene-for-gene mechanism preferred as short-term
  solution
• in lettuce 26 resistance genes against Bremia
  pyramided
• continuous selection pressure
• continuous break-throughs
• occasionally high production losses and economic
  costs

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The narrow genetic base

• narrow genetic base results in vulnerability
• varies per crop
• many varieties share same genetic make-up
• lack of Phytophthora resistance led to Irish
  potato famine (1840s) and emigration to USA
• Southern corn blight disease resulted in major
  crop losses in USA (1980s)
• similar patterns observed for coffee rust in
  Brazil, downy mildew in onions, etc.
• remedy wider gene pool, exotic crosses

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External input demands

• modern breeding has relied heavily on high
  external inputs
• fertilizers
• pesticides
• fertilizers
• use rate not sustainable
• pesticides
• health hazards
• new resistances in target species
• occurrence of opportunist pathogens
• high costs for small-scale agriculture
• debt cycle

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Lack of public funding

• developed countries
• shift to private industry
• focus on purchasing power
• developing countries
• public sector focus on staple crops
• focus on food security
• risk loss of crops from human diet
• loss of valuable diet components
• loss of locally adapted crops

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Access to technology

• privatization of breeding results in decreasing
  access to technology
• technological tools require highly skilled
  expertise, state-of-the-art facilities, licensing
  of IPR-protected technologies (e.g. AFLP)
• breeding accessible to anyone
• modern breeding using recent technology
  accessible to increasingly fewer companies
• who is in control?

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A summary of risks

• human health due to high toxin levels
• selection for pathogen resistance
• crop vulnerability
• narrowing the genetic base
• unsustainable production
• high external input demands
• widening gap in breeding
• concentration in industry
• focus on major crops

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Some questions

• Are these risks typical for traditional breeding,
  or equally or increasingly relevant for GM
  technology?
• What is relevant?
• the divide between GM crops and traditionally
  bred crops?
• the divide between breeding for the public domain
  or for protected products and tools?
• the divide between former public breeding by many
  institutes and the current dominance of private
  breeding in few agrochemical multinationals?

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Conclusions

• risks technical and institutional
• risks short-term and long-term
• risk perception dependent on position
• historical evidence shows all risks were
  recognized and contained
• almost all risks similar or larger with GM
  technology
• in particular institutional risks
• introduction of undesirable traits through
  genetic linkage