WARFARIN from moldy hay of sweet clover

Melilotus alba and Melilotus officinalis

infected with

Penicillium nigricans and Penicillium jensi

Photos by Elizabeth J. Czarapatahttp://dnr.wi.gov/topic/invasives/fact/whitesweetclover.htmlhttp://dnr.wi.gov/topic/Invasives/fact/YellowSweetclover.html

Family: Fabaceae or Leguminosae

Plant of the Day:

WARFARIN from moldy hay of sweet clover

Melilotus alba and Melilotus officinalis

infected with

Penicillium nigricans and Penicillium jensi

Photo from Johnny’s Selected Seedshttp://www.johnnyseeds.com/p-7050-sweet-clover-og.aspx

Coumarin in sweet clover converted to dicoumarin by molds

Anticoagulant killed cattle in 1920s and 1930s

Karl Paul Link and graduate student Mark Stahmann identified dicoumadins

Named after WARF (Wisconsin Alumni Research Foundation) because they provided $$$

Use as rat poison and then medical use vs. blood clotting (e.g., to prevent heat attacks).

Plant of the Day:

Bridget O

'Donnel im

age from W

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http://www.ccsdedtech.com/cc/projects/scrapbook/potato/PotatoDinner.gif

http://botit.botany.wisc.edu/toms_fungi/images/phytspor.jpg

“Irish Potato Famine” caused by a water mold and by genetic uniformity of potatoes

Conservation of Crop Genetic Diversity Why conserve crop genetic diversity?Example 1

Conservation of Crop Genetic Diversity

Southern corn leaf blight epidemic (1970)

USA-wide epidemic leading to a loss of 15% of corn production in USA

• Some southern states lost half of crop and half of farmers

• Uniformity! All had same cytoplasm (chloroplast genome) because male sterility made hybridization easier.

Why conserve crop genetic diversity?Example 2

Rice is the major staple for half of humanity

Facing climate change

International Rice Research Institute (IRRI), Los Baños, Philippines

Image source: http://irri.org/our-work/research/better-rice-varieties/climate-change-ready-rice

Facing climate change

Image source: http://irri.org/our-work/research/better-rice-varieties/climate-change-ready-rice

International Rice Research Institute (IRRI), Los Baños, Philippines

Drought and disease threaten YOUR coffee.

Photos: Above: Tim Johnson/MCT/Landov Right: Paulo Whitaker/Reuters/Landov Below: International Center for Tropical Agriculture/Flickr

Figure 1 Genetic bottlenecks imposed on crop plants during domestication and through modern plant-breeding practices.

S D Tanksley, and S R McCouch Science 1997;277:1063-1066

Published by AAAS

Crop wild relatives (CWR)

Figure 4 (Left) Wild rice species O. rufipogon from Malaysia. [Photo courtesy of C. Martinez, Centro Internacional de Agricultura Tropical] (Right) Modern rice variety from China.

S D Tanksley, and S R McCouch Science 1997;277:1063-1066Published by AAAS

Crop wild relatives

Figure 5 (A) Wild tomato species L. hirsutum from Peru that produces small, inedible fruit that does not turn red upon ripening.

S D Tanksley, and S R McCouch Science 1997;277:1063-1066Published by AAAS

Crop wild relatives

History of concern about crop genetic resources since 1970s

Southern corn leaf blight 1970 • some southern states lost half of crop and half of farmers• would have been worse if weather had not changed• uniformity due to the use of “T cytoplasm” – male sterility made

hybridization easier

IBPGR and CGIAR formed in 1970s• IBPGR, International Board of Plant Genetic Resources • Later IPGRI, International Plant Genetic Resources Institute• Now “Bioversity International” http://www.bioversityinternational.org/

• CGIAR -- Consultative Group on International Agricultural Research www.cgiar.org

– 15 International centers CIP, CIMMYT, IRRI, CIAT, etc. and national programs

Grass-roots conservation organizations• Seed Savers Exchange (SSE)• Native Seeds / SEARCH

Crop Genetic Resources

Germplasm = “The bearer of the characteristic nature of the species and of the individual” ((Weissman 1883)

Germplasm includes ALL of these: • traditional cultivars (AKA: landraces, primitive

cultivars, folk varieties, farmers’ varieties)• wild relatives • weedy relatives• “advanced” or “modern” commercial cultivars• advanced breeding lines, “elite” germplasm

The value of genetic diversityFor plant breeders – diversity is the raw material

for future crop improvement

• Landraces (= traditional or folk cultivars) with traits for pest resistance, yield, flavor, nutrition, drought resistance, salinity tolerance, etc.

– An example: Harlan’s “miserable” wheat in handout.

• Wild relatives have contributed to crops genes for disease and pest resistance, wider adaptation (climate), improved quality (protein, oil, flavor, soluble solids), self-fertility, short stature, etc..

– Surprising alleles (e.g., alleles to improve cotton fibers from wild relatives that do not have fibers on seeds.)

Harlan’s “miserable wheat” quote

The value of genetic diversity

For traditional farmers – diversity for food security

• adaptation to specific local conditions (deeply rooted Hopi maize)

• risk reduction – dependable harvest in unfavorable conditions (see handout example)

• favored foods, symbols of identity• may be more suited to marginal lands and

conditions than “Green Revolution” HYV (high yielding varieties), which are not necessarily efficient in scarce resources (require high inputs of water and nitrogen)

Hernandez-X. quote (cited by Wilkes)

Two complementary conservation strategies:

Ex-situ conservation

= collecting and preserving in germplasm banks, botanical gardens, etc. (not in the plant’s natural habitat)

In-situ conservation

= “in place” or “on farm” landraces on traditional farms, wild species in their natural habitats

Conservation of crop genetic diversity

Conservation of crop diversity “ex-situ” in gene banks

Cary Fowler/Global Crop Diversity Trust (both on left); http://www.ars.usda.gov/sp2userfiles/Place/54020500/images/H3-18Lana.jpg

• National and international germplasm banks preserve crop diversity “ex-situ”

USDA National facility in Fort Collins, Colorado

Global Crop Diversity Trust www.croptrust.org

Ultimate backup “ex-situ” facility in the arctic:

Svalbard Global Seed Vault

Conservation of crop diversity “in-situ” = on farm

Ex-situ conservation

Advantage: accessible for plant breeders for future plant improvement

• evaluation of traits (morphological, molecular, agronomic, nutritional, etc.)

• changing values means that “worthless”

ones may turn out to be valuable (high lysine corn, resistance to new pests)

Pitfalls of ex-situ conservation– lose variability due to genetic drift as only a

small portion is grown out– selection for ability to retain viability in

storage– grow-out conditions unlike those of

traditional farmers on marginal lands (not evolving in response to natural environmental conditions)

– mistakes, human error leads to losses– budgetary constraints, political instability

• (Threats to Pavlovsk germplasm in Russia, unrest or war, e.g., Aleppo germplasm bank in Syria.)

Ex-situ conservation Ex-situ conservation

In-situ conservationNow widely seen as an important complement to

ex-situ conservation. – allows continued evolution in response to

changing environments (new pathogens, pests, stresses)

– keep crops in their “cultural-ecological context” the human-modified systems in which they evolved

– ecological complexity of traditional agriculture, use of micro-habitats

– accessible to traditional farmers (although less accessible to plant breeders)

***Please see handouts and other readings for more nuanced discussion.

Grassroots seed saving efforts

Contribute to grassroots seed-saving organizations

Try it yourselfLearn to save seed of your own vegetables (some are easy).

Photo courtesy Linda Black Elk

Photo source: Paul Gepts, UC Davis http://www.plantsciences.ucdavis.edu/gepts/pb143/LEC02/bean1.gif