Presentation - IAC 2016, New Delhi Download

Transcript
International Agrobiodiversity Congress (6 - 9 November, 2016, New Delhi)
To discuss…
• Journey of crops
• Classical plant collectors and concepts
• Status of world PGR in Gene banks
• Genetic erosion – Levels, major causes
• Genetic Diversity indicators (ex situ)
• Assessing genetic erosion
• Recommendations
Journey of Crops
Crops that travelled around the world along
with people
Wheat from Near East (Israel)
Maize, Tomato, Pepper (chilli) from South
America
Banana from South East Asia (Malaysia)
Carrots from Afghanistan
Potato from Andean region, South America
Onion from Central Asia (Iran)
Pumpkins from Tropical America (Mexico)
Classical Collectors/ Concepts
• Queen Hatsheput (Egypt, 3500 years ago) – collected resin of myrrha plant
(Commiphora) and frankincense (Boswellia) trees near Somalia
• Christopher Columbus (Italy) – potatoes, sweet potatoes, maize, tomatoes,
peanut, cassava, cacao, peppers, tobacco, beans and squashes
• Thomas Jefferson (3rd President of USA) – Vanilla, tea, olives from Europe
• Nicolai Vavilov (Russia) –Centres of origin
• Carlos Ochoa (Peru) – Wild and endangered species of potato
• John George Jack (Canada) – Tree genetic resources
Classical Collectors and Concepts
• Jack Harlan (USA) - Centres of diversity
• Gregory WC & Krapovickas A – Groundnut
• Brown WL – Maize
• Hawkes JG (UK) & Otto Frankel (Australia) – PGR as a science
• Zeven AC (The Netherlands) and PM Zhukovsky (Russia) – Centres
of Origin.
Indian Context
• Emperor Ashoka (304-232 BC) patronized the
establishment of fruit and shade trees in his
kingdom.
• Emperor Akbar (1542-1605) established a
mango orchard (Lakhi Bagh) in Darbhanga,
Bihar during his regime.
Status of World PGR in Gene banks
• Over 1750 gene banks and 2,500 botanical gardens conserve a total of
7.4 million germplasm accessions and 80,000 species respectively
around the world.
• Currently 870,971 samples are deposited at Svalbard, Norway by 69
gene banks. This is about one third of globally distinct accessions of 156
crop genera.
Svalbard Global Seed Vault, Norway (870,971 seed samples-233 countries)
Global Ex Situ holdings of commodity groups
Crop Group
Accessions
Crop Group
Accessions
Cereals
3,157,578
Forages
651,024
Food legumes
1,069,897
Sugar crops
63,474
Roots and tubers
204,408
Fibre crops
169,969
Vegetables
502,889
Medicinal, aromatic 160,050
and spice crops
Nuts, fruits and
berries
423,401
Industrial and
ornamental plants
152,325
Oil crops
181,752
others
262,993
FAO (2014)
The Ten Largest germplasm collections…
Institution
Country
Accessions
NPGS (National Plant Germplasm System)
USA
576,187
ICAR-NBPGR (National Bureau of Plant Genetic
Resources)
India
429,110
ICGR-CAAS (Institute of Crop Germplasm ResourcesChinese Academy of Agricultural Sciences)
China
410,000
VIR (N I Vavilov Research Institute of Plant Industry)
Russia
322,238
NIAS (National Institute of Agrobiological Science)
Japan
243,463
CIMMYT (Centro Internacional de Mejoramiento de
Maiz y Trigo)
Mexico
164,320
IPK (Leibniz-Instiut fur Pflanzengenetik und
Kulturpflazenforschung)
Germany
151,408
ICARDA (International Center for Agricultural Research
in the Dry Areas)
Syria
147,076
IRRI (International Rice Research Institute)
Philippines
124,052
ICRISAT (International Crops Research Institute for the
Semi-Arid Tropics)
India
119,524
Ex situ collection at CGIAR centres
Centre
Number of Accessions held
Africa Rice
19,985
Bioversity International
1516
CIAT
64,721
CIMMYT
164,320
CIP
16,061
ICARDA
147,076
ICRAF
2005
ICRISAT
119,524
IITA
27,232
ILRI
20,229
IRRI
124,052
Holdings of commodity groups in NGB, India
(As on 30 Sep.2016 - 4,29,110 accs)
Crop Group
Accessions
Crop Group
Accessions
Cereals
1,59,817
Forages
6,789
Millets
57,951
Pseudo cereals
7,225
Food legumes
65,211
Fibre crops
14,368
Vegetables
25,510
Medicinal, aromatic 10,750
and spice crops
Nuts & fruits
272
Ornamental plants
646
Oil crops
57,923
Agroforestry
1,642
Others (safety
duplicate, trial
materials)
21,006
www.nbpgr.ernet.in
Can these rich Ex Situ collections be
protected from Genetic Erosion?
Genetic Erosion
 Steady loss of genetic diversity in on-farm or ex situ.
 The loss of variation in crops due to the modernization of agriculture.
 Replacement of landraces by modern productive cultivars with narrow
genetic base.
 Catastrophic outbreaks that forced to think about genetic erosion
Southern corn-leaf blight-USA
Coffee rust-Brazil
 Genetic uniformity is the basis of vulnerability to epidemics.
Genetic Erosion: Levels
Loss of alleles or genes
Loss of genotypes or land races
Genetic Erosion: Major Causes
 Narrow genetic base in the original collections (Less than
representative sample collected and the initial bottleneck
effect).
 Lack of Knowledge on biology, breeding system, mode of
reproduction and pattern of genetic diversity.
 Lack of gene flow between different populations and natural
and artificial selection/interaction in heterogeneous
environments.
 Improper management/ regeneration procedures (genetic
drift and shift).
 Raising global temperatures and climate change.
Why to prevent Genetic Erosion?
• Conserved genes successfully used in mitigating major
challenges. Wide range of variation will be required to meet
the demands placed by the climate change and adaptation
requirements in the future (FAO, 2015).
• Rust resistance in wheat varieties by incorporation of single
major gene that conferred resistance to specific races of rust
pathogens (Borlaug, 1953)
• Chromosomal translocation from rye to wheat has conferred
adaptation potential to wheat in marginal environments
(Borner et al. 2000)
• Drought tolerant maize/stress resilient maize in Africa
(Chebotar et al. 2003)
Genetic Diversity Indicators in Ex situ
• Number of crop species, subspecies or geographic categories
adequately sampled in gene banks
• Number of accessions held in the gene bank
• Number of collections or gene banks
• Country distribution of seed gene banks
• Coverage in collections of crop diversity
• Backup duplication provisions
• Extent of usage and representation in core collections
• Collection health, accession viability
• Documentation and evaluation of collection
Modified from Brown and Brubaker (2002)
Indicators of genetic diversity in wild genepool
• Number of wild species, subspecies or geographic
subdivisions of taxa related to crops adequately sampled in
the gene bank.
• Coverage of species range.
• Evolutionary relationships and taxonomic resolution.
• Accession viability, documentation and duplication.
• Number and frequency of accessions used.
• ‘Prebreeding’ activities, including evaluation.
Modified from Brown and Brubaker (2002)
Assessing Genetic Erosion in Gene banks
Factors causing genetic erosion in Gene banks
• Physiological changes in seeds (Barley & Wheat –chromosome
aberration, loss of seed vigour)
• Inappropriate storage conditions and management procedures
• Accidental errors/mixing of seed samples before regeneration
• Lack of adequate financial resources for maintaining collections
• Accidental destruction, fire.
To continue…
Factors causing genetic erosion in Gene banks
• Damage of field collection (animals, natural disasters, pest outbreak)
• Armed conflicts, war (ICARDA gene bank at Alleppo damaged in
2012)
• Regeneration backlogs
• Economic instability
• Lack of resources and skills
• Abiotic stresses (heat and drought), loss of samples during
regeneration
Genetic erosion in Gene bank collections depends on the quality and quantity of the
original material stored & on the conditions under which the germplasm is
maintained and regenerated.
Population size at the time of collecting and
at the time of regeneration
• Number of accessions and their isolation during collection and
at the time of regeneration are also indicators for genetic
erosion. (Pigeonpea geneflow studies)
• Small Populations are at risk of loss of alleles (rare allelesmissing the allele detection), increased inbreeding and
extinction due to random environmental events. (Pearlmillet
??)
• Direct comparison of samples collected at different times in
the ex situ collections are warranted to assess the genetic
erosion (Adilabad paddy)
Extent of Alleles lost in Ex Situ Collections
(Indicative case studies)
Wheat accessions (Borner et al., 2000)-High
Maize (Wen et al., 2011 ) 22%
Rye accessions (Chebotar et al., 2003) – 50%
Brassica oleracea (Soengas et al., 2009) – significant
• Stable and unique morphological traits (initial and regenerated
samples) of ex situ conserved samples.
• Characterization based on standardized format (internationally
agreed descriptors)
Recommendations
• Traits of importance to be documented exhaustively at collection
time.
• Define the genetic integrity at the time of collection and the
method of maintenance.
• Sample size at the time of collection and subsample size for
regeneration should follow gene bank standards.
• Evaluation of collections for traits of current importance (Iron,
Zinc, recent biotic stresses, climate change etc. in paddy) for
avoiding genetic drift.
• Revisiting the original locations of collection to assess the extent
of genetic erosion.
Recommendations (Contd.)
• Research on protocols and scales and indicators (individual cropwise) to maximize the genetic integrity.
• Follow proper regeneration protocols (Germplasm adaptation to
environment, taxonomy, reproductive biology and genetic
diversity studies are to be taken up).
• Modern tools may be used to estimate the genetic erosion and
the resultant diversity created during conservation should also be
utilized for crop improvement.
Conclusion
Best strategy to minimise genetic erosion
combines ex situ conservation with on-theground (in situ) conservation by farmers in their
agro-ecosystems and of crop wild relatives in,
for example, areas protected for their
environmental value.
Way Forward: Genebanks Relevance
• Develop standards to accommodate diversity within a variety in
“DUS”
Government of AP/Telangana and NGOs (WASSAN/ DDS)
• Entry of tagged landraces in to CMSS (Govt subsidies, Consumption &
Commercialisation – Conserved sustainably)- Ananathpur
• “Navadhanyalu” several crop landraces in one packet for rainfed
cultivation- Ananthapur & North Coastal AP
• Organic rain-fed cultivation –Medak, Telangana
Prebreeding commercialisation from genebanks (HPRC -ICRISAT)
• Genebanks and crop breeders to exploit synecology and diversified
agriculture concepts to create diversity
• Establish urban market linkage for tagged landraces
• Reintroduce in to wild and follow up