Evaluating Risks in Traditional Breeding: Assessing Toxicity, Allergens, and Institutional Challenges

1. Traditional breeding:no risks? Bert Visser Copenhagen, 13 december 2005

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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)

8. 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

9. 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)

10. 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.)

11. 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

12. 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)

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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?

21. 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

22. 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?

23. 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