the role of genetic diversity for building resilience for food security
TRANSCRIPT
The role of genetic diversity for building resilience for food securityEhsan Dulloo PhD., Mary Thompson, Bioversity International
University of Oxford, UK, 2-3 October 2013
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Bioversity International is a research-for-development organization seeking solutions to global issues through the use and conservation of agricultural and forest biodiversity.
What is agricultural biodiversity (ABD)? Variety of animals, plants and microorganisms that are used directly or indirectly for food and agriculture including crops, livestock, forestry and fisheries. Also farmers’ knowledge and experience regarding this diversity and it’s management.
Global biodiversity
Biodiversity affected by agriculture
Agricultural biodiversity
ABD: a significant subset of global biodiversity
• ABD as a socio-ecological system (SES)• Resilience property of SES• Genetic diversity in ABD will increase the ability for food
systems to adapt and transform in the face of global changes and shocks
• Maintain genetic health of species, breeds and varieties across landscape
• Supports ability of farmers to respond to shocks market fluctuations, natural disasters and global climate change
Agricultural biodiversity and resilience
Why is genetic variation important?
• Maintain adaptive potential of species/populations and the fitness of individuals to help ensure their survival
• “Evosystems services” perspective (Faith et al, 2010)
• High genetic diversity = increased future options for food security
• International Treaty on Plant Genetic Resources for Food and Agriculture“Alarmed by the continuing erosion of these resources” [i.e. PGRFA]
• Global Plan of Action on Conservation and Sustainable Use of Plant Genetic Resources for Food and Agriculture
“Genetic erosion is reported to continue many regions of the world and the genetic vulnerability of crops has further increased”.
• Strategic Plan for Biodiversity 2011-2020Aichi Target 13: By 2020, the genetic diversity of cultivated plants and farmed and domesticated animals and of wild relatives, including other socio-economically as well as culturally valuable species, is maintained, and strategies have been developed and implemented for minimizing genetic erosion and safeguarding their genetic diversity.
No clear (rather conflicting) evidence of actual loss of diversity is occurring overall (van de Wouw et al. 2009)
Baseline studies
• Genetic erosion of coffee genetic resources in field collection (Madagascar, Ethiopia, Costa Rica)
• Genetic erosion in coconut (South Asia), pearl millet (Rajasthan), soybean (China)
• Spatial analysis of molecular data: Cherimoya in the Andes
• Genetic Erosion of Cassava in the Peruvian Amazon
• Decline in the numbers of local rice varieties in China from 46,000 in the 1950s to slightly more than 1,000 in 2006 (Secretariat of the CBD, 2010); similar statistics are available for India and Vietnam
Genetic erosion in pearl millet• Rapid survey using participatory approach with 459
farmers across 174 villages in 14 pearl millet growing districts in Rajasthan Province of India in 2002
• ICRISAT collecting database were used for the identification of the survey sites; three zones were identified:
• 25- 75% replacement by high yielding varieties
• Analysis indicated genetic erosion of land races based on:• Low yield of landraces• Promotion of high yielding varieties• Changing cropping patterns• No organized seed system for landraces• Market preference for HYV
No change in diversity – case of pearl millet and sorghum in Niger - Bezançon et al. 2009
Many local varieties of millets and sorghum in Niger were replaced by improved ones, but overall diversity of pearl millet and sorghum varieties has not changed between 1976 and 2003 in the terms of varietal names and DNA markers (Bezançon et al. 2009)
2003
1976 50-55 days 55-60 days 60-65 days 65-70 days
70-75 days
75-80 days
80+ days
Based on these studies :
• It is clear that genetic erosion is of concern but evidence is still lacking about:– rate of loss– variation among crops,
situations– economic implications
• Monitoring changes in genetic diversity and analyzing causes of change is still needed
Challenges in understanding trends in genetic diversity
“You can’t manage what you don’t measure”(Peter Drucker)
There is no global, harmonized observation system for delivering regular, timely data on agricultural biodiversity change
Different organizations and projects adopt diverse measurements, with some important biodiversity dimensions, such as genetic diversity, often missing
Only limited information available regarding actual threat status
Conventional monitoring efforts, where they exist at all:• subject to ad hoc approaches that lack rigorous survey and sampling approaches• do not systematically involve the participation of local-level actors• usually based on collections instead of direct observations in the field
Current measurements and indicators (crops)
• Primarily focus on ex situ genebanks– Do not measure state or trends of diversity at
the genetic level in real world agroecosystems
• FAO indicators – monitoring progress of the implementation of second Global Plan of Action. 66 indicators covering 4 main areas viz. – In situ conservation and management (12
indicators)– Ex situ conservation (12 indicators)– Sustainable use (22 indicators)– Building institutional and human capacities (20
indicators)
• No. of species• No. of accessions within collections• Geographical origin of accessions
BIP: Ex situ collection indicator
Principle: Accessions entering the collection can be characterized for their originality
Index: An integrative function reflecting the collection’s enrichmentAny new accessions entering the collection at a given time is compared to the accessions already present: • Is it a new species?• Does it come from a new area?
The more original it is, the more weight it is given. The weight is based on a log function so that it decreases when a species is well represented.
Enrichment Index of ex situ crop collections as an indicator on the status and trend of crop genetic diversity
Indicators for in situ diversity
• In situ measurements have been lacking in their capacity to encompass a sufficient breadth of genetic diversity characteristics
• Number of varieties• Diversity Indices- Shannon,
Simpson, Pielou’s, Nei, • None of these combine the
study of allelic diversity and a concern on evenness of the spatial distribution of alleles
Global indicators: Significant traditional variety diversity continues to be managed by small scale farmers in the developing world.
Jarvis et al., 2009 PNAS
Hungary, Mexico, Peru
• -LN(1-Farm evenness)•0.0 •0.5 •1.0 •1.5 •2.0
•LN Farm
richness
•0.0
•0.5
•1.0
•1.5
•2.0
A
B
2-3
2-3
39-89
4-20
5-14
1-2
4-5
9-74
Morocco, Ethiopia
1-24-12
1-2
5-274-5
15-28
Burkina faso
Nepal and Vietnam
Peru
Community Richness
House Hold richness
Richness = 9Evenness A > B
2-3
9-18
Uzbekistan3-5
6-19
Leading the collaboration of >60 institutes world wide
• HT Integrated Indicator- Bonneuil et al. (2012)– Varietal richness, Spatial evenness; Effect of between-variety genetic
diversity; Within- variety genetic diversity
• Tested against a historical dataset on bread wheat varieties dating back to 1978: Allelic diversity; Acreage share of each variety; Contribution of within variety diversity to total genetic diversity
• More varieties (the varietal richness factor) can mean less diversity when
(i) their genetic structure is more similar (the effect of between-variety genetic diversity), or (ii) when more diverse landraces are replaced by many homogeneous lines (the effect of within-variety genetic diversity) or (iii) when one or a few varieties become hegemonic in the landscape (the spatial evenness effect)
A New Integrated indicator
Indicators for Resilience in SEPLs: Development and Field Testing
• Measuring community’s capacity to adapt to change while maintaining biodiversity.
Four categories comprising 20 indicators on:• Ecosystems protection and the maintenance of biodiversity• Agricultural biodiversity• Knowledge, learning and innovation• Social equity and infrastructure
• Developing strategies for • Conserving biodiversity at various scales (from genetic to landscape level)• Sustaining evolution and adaptation processes that maintain and generate diversity• Empowering local communities and strengthening their role as innovators and
custodians of biodiversity
Socio-ecological resilience indicators
Linking initiatives to genomic observatories and networks
• CGIAR Research Programs established research sites upon which to build future networks
• Examples from the forestry sector– EVOLTREE: Network of
Intensive Study Sites (ISS)– EUFORGEN and EUFGIS– CRP 6 Sentinel Landscapes
High Priority locations identified in SSA:• finger millet
(Burundi, DRC, Ethiopia, Kenya, Rwanda and Uganda),
• pearl millet (Sudan),
• garden peas (Ethiopia) cowpea in several countries
Priority Areas for Crop Wild Relatives
Global priority genetic reserve locations for wild relatives of 12 food crops
• Genetic diversity is important for building resilience for crops and landscape level- sustaining evolutionary processes
• Global concerns of genetic erosion- conflicting evidences• Challenges in genetic monitoring • Much has been done in the past to document genetic diversity
across a whole range of scale –ex situ, in situ, on farm, production landscape, forest gene conservation units
• Opportunities for expanding genomic network to cover agrobiodiversity sites
• Contribute to Strategic plan for Biodiversity - Aichi target 13
Take home message
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