Crop Adaptation to Climate Change (Yadav/Crop Adaptation to Climate Change) || Crop Germplasm Diversity: The Role of Gene Bank Collections in Facilitating Adaptation to Climate Change

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Chapter 25

Crop Germplasm Diversity: The Role of GeneBank Collections in Facilitating Adaptation toClimate ChangeLaura K. Snook, M. Ehsan Dulloo, Andy Jarvis, Xavier Scheldeman, and Margaret Kneller

Climate Change and Agriculture

The impacts of climate change on agricultureare projected to be significant. Assuming green-house gas emissions continue to rise at currentrates (the A2 or “business as usual” scenarioof the IPPC; Nakicenovic & Swart 2000), thetemperature of the earth’s surface is expected toincrease by about 3◦C, on average, during thetwenty-first century. Temperature change will beaccompanied by changes in rainfall regimes andan increased frequency of droughts and floods(IPCC 2007). The specific spatial distribution offuture climates (mean air temperatures and pre-cipitation) is difficult to predict; however, we canexpect three future scenarios: (a) the climates insome areas will become analogous to current cli-mates in other areas, (b) some projected futureclimate regimes will be different from any cur-rent climates (so-called novel climates), and (c)some current climates will disappear (Williamset al. 2007). These changes will shift the areassuitable for a wide range of crops.

Jarvis et al. (2009a) used a modification ofthe Ecocrop model in DIVA-GIS (Hijmans et al.2005) to map the global distribution of areas

suitable (based on monthly precipitation andtemperature) for cultivation of 50 crops. Com-paring current crop suitability maps to projectedsuitability maps for 2055, based on the A2 SRESemission scenario, they found that most cropssuffered decreases in suitable area (on average),while other crops gained ground. Models pro-jected an increase in areas suitable for cultiva-tion in the northern latitudes and declines in sub-Saharan Africa and the Caribbean as well as theSahel, parts of southern Africa, India, and north-ern Australia (see Fig. 25.1). Similar analyses forfood-insecure regions carried out by Lobell et al.(2008) also revealed that agriculture in southernAfrica and South Asia would suffer as a result ofclimate change.

Warming temperatures are expected to reducecrop yields, even in areas that are currently con-sidered suitable for their cultivation (Ortiz et al.2008). Outputs from 23 global climate modelsshow a probability of >90% that by the endof the twenty-first century, growing season tem-peratures in the tropical and subtropical regions(portions of Asia; Africa; South, Central, andNorth America; and the Middle East) will exceedthe most extreme seasonal temperatures recorded

Crop Adaptation to Climate Change, First Edition. Edited by Shyam S. Yadav, Robert J. Redden, Jerry L. Hatfield,Hermann Lotze-Campen and Anthony E. Hall.c© 2011 John Wiley & Sons, Ltd. Published 2011 by John Wiley & Sons, Ltd.

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496 CROP ADAPTATION TO CLIMATE CHANGE

Fig. 25.1. Average change in area suitable for growing 50 major world crops, derived from a modified Ecocrop approach.Legend refers to percent of area lost or gained, summing all crops (Jarvis et al. 2009c).

from 1900 to 2006 (Battisti and Naylor 2009).Even mid-latitude crops will suffer under thosehigher temperatures, as evidenced by the reduc-tion in agricultural yields of 21–36% (dependingon the crop) as compared to the previous yearas a result of record heat in Europe during thesummer of 2003 (Easterling et al. 2007 in Battistiand Naylor 2009). Temperature increases are ex-pected to limit the potential positive effects ofelevated CO2 on photosynthesis (Tubiello et al.2007). Climate change will also modify grow-ing seasons and result in more frequent extremeweather events, including severe droughts andflooding. Changing climate is already alteringthe distribution and life cycles of pests and dis-eases, which will affect both crop production andprofitability (Tubiello et al. 2007; Diffenbaughet al. 2008). Some studies see moderate to severeadverse effects on agricultural productivity oc-curring within the next two decades (Easterlinget al. 2007; Lobell et al. 2008).

Farmers’ ability to adapt to climate changewill require their effective deployment of culti-vars or crop species suited to projected futureconditions, with appropriate thermal time andvernalization requirements and/or resistance toheat shock and drought (Howden et al. 2007;Ortiz et al. 2008) or other abiotic conditions,like salinity or flooding. These alternative cul-tivars or crops will also need to be resistant

to pests and diseases of which the ranges orthe virulence may increase as a result of cli-mate change. The diversity of genetic traits inseeds and other reproductive materials held ingermplasm collections represents our most im-portant resource for adapting agriculture to cli-mate change. The potential to harness the diver-sity of these materials depends on the breadthand completeness of gene bank collections; thequality of management and the genetic integrityand security of those collections; the availabil-ity of and access to information on critical traitsof the conserved materials; and access to repro-ductive material by researchers, breeders, andother potential users, including farmers, aroundthe globe.

The breadth and completenessof germplasm collections

Gene bank collections were established to con-serve the diversity of cultivars developed overmillennia through selection by farmers all overthe world. In the early twentieth century, theRussian scientist Nikolai Vavilov mounted ex-peditions to the centers of diversity and originof crops, obtaining nearly 250,000 seed samplesof cultivars grown by farmers (“landraces”) thatwere stored at the collection in St. Petersburgthat now bears his name. His efforts were



CROP GERMPLASM DIVERSITY 497

followed by those of others, among them areHarry and Jack Harlan, Otto Frankel, ErnaBennett, and M.S. Swaminathan, who collectedcrop diversity and lobbied for its conserva-tion (Fowler and Mooney 1990). The diversityin these collections of landraces provided theraw materials that plant breeders used to createhigh-yielding varieties combining the traits ofmultiple ancestors. Starting in the 1960s, theInternational Agricultural Research Centres sup-ported by the Consultative Group on Interna-tional Agricultural Research (CGIAR) and otheragricultural research organizations bred modernvarieties of 11 major food crops that tripledfood production in developing countries between1961 and 2000. The genetic qualities of theseimproved varieties, independent of the effect offertilizer and other inputs, were estimated tohave contributed to an increase in crop yieldsof 21–43%, fueling the “Green Revolution”(Evenson and Gollin 2003).

The success of plant breeding resultedin the decisions by many farmers to planthigh-yielding varieties, abandoning their tra-ditional landraces. Recognizing that this pro-cess would lead to the loss of genetic re-sources that would be useful for continuingcrop improvement, the Food and AgricultureOrganization (FAO) of the United Nations es-tablished the International Board for PlantGenetic Resources (IBPGR) (now BioversityInternational) specifically to collect agriculturalbiodiversity and to conserve it in gene banks,where it would be maintained to be used forthe benefit of current and future generations.Between 1976 and 1996, 558 collecting mis-sions were carried out that returned with 225,980samples from 137 countries. Today, the 11gene banks of the Consortium of InternationalAgricultural Research Centres supported by theCGIAR hold more than 740,000 samples of 3400species representing 612 genera. Fifteen largenational collections hold a total of 162,772 sam-ples of 1906 species in 463 genera. In total, theworld has 1750 gene bank collections that con-serve 7.4 million samples, about 30% of them

distinct (FAO 2010), obtained either throughcollecting from farms and natural habitats orthrough germplasm exchange with other collec-tion holders.

However, today’s gene bank collections arenot representative of the full range of crop genepools and traits of interest for increasing produc-tion and adapting to climate change. Many cropspecies that are regionally, rather than globally,important, remain generally underrepresented incollections. Although 45% of gene bank samplesare of cereals, even these collections do not pro-vide full coverage of the crops’ gene pools (FAO2010). An important example is maize (Zeamays), which originated in Mesoamerica, yet hasbeen grown by farmers in Africa for hundreds ofyears. Human and environmental selection pro-duced varieties adapted to the diverse growingconditions of the African continent, which wereoften harsher than the conditions in Mesoamer-ica. Under projected future conditions, the traitsof some of these varieties will become importantin regions beyond those where they are currentlygrown. However, African maize varieties are un-derrepresented in international collections, ac-counting for only 5% of maize holdings in majorgene banks. Although national gene banks of-ten conserve material that is not represented ininternational gene banks, their collections, too,fall short of representing the diversity available(Burke et al. 2009).

The wild relatives of crops, which have con-tinued to evolve under the selective pressure ofthe environment while their related crops havebeen selected by farmers for other traits, repre-sent another important component of crop genepools needed for adaptation to climate change.Crop wild relatives have been crucially impor-tant sources of traits and will continue to beneeded for breeding. Their genes can providecultivated crops with resistance to pests and dis-eases and abiotic stresses including tempera-ture extremes and freezing, salinity, or flooding(Hajjar and Hodgkin 2007). Populations of croprelatives growing in the wild are threatened byhabitat destruction, deforestation, urbanization,




grazing, agricultural expansion, and harvesting(Khoury et al. 2010), as well as climate change(Jarvis et al. 2008). A major project carried outin Armenia, Bolivia, Madagascar, Sri Lanka,and Uzbekistan to conserve in situ, in the wild,the wild relatives of wheat (Triticum aestivum),barley (Hordeum vulgare), rye (Secale cereale),pulses (various genera of the family Fabaceae),beet (Beta vulgaris), pear (Pyrus communis),potato (Solanum tuberosum), sweet potato (Ipo-moea batatas), cassava (Manihot esculenta),chile (Capsicum annuum), pineapple (Ananascomosus), peanut (Arachis hypogaea), quinoa(Chenopodium quinoa), cacao (Theobroma ca-cao), cashew (Anacardium occidentale), papaya(Carica papaya), blackberry (Rubus fruticosus),rice (Oryza sativa), banana (Musa acuminata, M.balbisiana), coffee (Coffea arabica), yam (vari-ous genera of the family Dioscoreaceae), vanilla(Vanilla planifolia), black pepper (Piper ni-grum), cinnamon (Cinnamomum verum), onion(Allium cepa), almond (Prunus dulcis), pista-chio (Pistachia vera), walnut (Juglans regia),and apple (Malus pumila), has yielded guide-lines for expanding this effort (Hunter andHeywood 2011; Hunter and Thormann 2007,www.cropwildrelatives.org). However, to ensurethat the genetic diversity of these populations isaccessible to breeders and available in future,samples must also be collected and maintainedex situ.

Samples of crop wild relatives are generallyexpensive to maintain in gene banks because theyhave not been selected for qualities that facilitatethe storage of the seeds of many crops, and alot of them are perennial. As a result, wild rela-tives of crops are underrepresented in gene banks(FAO 2010). It has been estimated that 94% ofthe European crop wild relatives are not includedin ex situ collections (Maxted and Kell 2009 inKhoury et al. 2010). An analysis of gaps in col-lections of wild relatives of 13 globally importantfood crop groups (chickpea (Cicer arietinum),common bean (Phaseolus vulgaris), barley, cow-pea (Vigna unguiculata), wheat, maize, sorghum(various species of the genus Sorghum), pearl

millet (Pennisetum americanum), finger millet(Eleusine coracana), pigeon pea (Cajanus ca-jan), faba bean (Vicia faba), and lentil (Lensculinaris)) was undertaken to establish the sta-tus of conservation (in situ and ex situ) of thesespecies, and to prioritize sites for future collect-ing, with special attention to the effects of cli-mate change. Nearly 29,000 herbarium and genebank species occurrences were analyzed for 643wild taxa belonging to these gene pools. The re-sults showed that significant gaps still exist inex situ collections and that protected areas donot currently provide adequate conservation ofcrop gene pools. For example, climate changeis projected to lead to a major loss of wild di-versity in central Africa, the eastern Mediter-ranean, and Central America. Priority locationsfor collecting are found in Africa, northern Aus-tralia, Central America, and the Andes (see Fig.25.2). Because as many as 39 species occur sym-patrically in parts of Africa, multiple gaps couldbe filled with targeted collecting or establish-ment of genetic reserves there (Ramırez et al.2009). More detailed information is available at(http://gisweb.ciat.cgiar.org/GapAnalysis/).

The integrity and securityof collections

Gene banks conserve seeds and other reproduc-tive materials ex situ in the absence of natural(environmental) and artificial (farmer) selectionpressures. Cereals and legumes are stored asseeds, usually at low temperature; species thatare regenerated vegetatively, for example, ba-nanas, potatoes, sweet potatoes, yams, and cas-sava, are stored in vitro (in slow growth) or undercryopreservation (in liquid nitrogen, at −196◦C).Field gene banks and botanical gardens conserveliving plants, typically of species of which theseeds cannot be stored, such as coconut (Coconucifera) and many other tropical tree species,or which do not breed true, as is the case formany fruit trees (see reviews by Engelmann andEngels (2002) and Thormann et al. (2006)). Toretain the viability of stored seed, gene bank




(a)

(b)

Fig. 25.2. Priority locations for in situ conservation and/or collections and conservation ex situ to fill gaps identified in currentex situ collections for the gene pools of wild relatives of 13 important crops, based on: (a) taxon level richness and (b) genuslevel richness; showing areas where multiple gene pools are not currently represented in collections or protected areas (Ramirezet al. 2010).

managers must periodically regrow plants fromtheir stored seed to produce fresh seed, a pro-cess referred to as regeneration. Gene banks aimto maintain the genetic integrity of the mate-rial at the time it was collected by followingbest practices to reduce genetic drift, the loss ofunique genetic diversity in samples, which canresult when a proportion of seeds lose their via-

bility and when materials are regenerated. Chal-lenges to regeneration include the control of plantdisease for vegetatively propagated species, pre-venting cross pollination by other sources duringregeneration of allogamous species, and regen-erating reproductive material requiring ecologi-cal conditions not available in the vicinity of thegene bank. Backlogs in regeneration, usually due




to lack of funding, are a critical problem in exsitu conservation (i.e., FAO 2010; Khoury et al.2010).

Many gene bank collections cannot be consid-ered secure. A recent review found that the num-ber of individuals conserved per sample (seeds,tubers, plants, tissues) is frequently below theoptimum for maintaining heterogeneous popula-tions (FAO 2010). Most national collections havelacked sufficient financial resources to maintainthe viability of their collections or to multiplythem sufficiently to ensure availability of repro-ductive material. In the developing world, fre-quent staff turnover has resulted in reduced man-agement capacity. Natural disasters, conflicts,and even changes in government have led to theloss of important collections, for example, overthe past few years in the Philippines (where thenational gene bank was affected by a typhoon)and in Iraq (where seeds were poured out bylooters who wanted the glass jars).

However, increased recognition of the cru-cial importance of these collections has led tosome important recent investments. Two WorldBank grants, totaling approximately $20 million,allowed the CGIAR Centres both to improvethe status of their collections and to developand make available knowledge and resourcesfor gene bank managers around the world (see,for example, the Crop Gene Bank Knowl-edge Base at http://cropgenebank.sgrp.cgiar.org/). The Global Crop Diversity Trust (GCDT)was founded in 2004 by FAO and Bioversity In-ternational, on behalf of the CGIAR, to supportthe conservation of the world’s plant genetic re-sources for food and agriculture. The GCDT israising an endowment and defining strategic ac-tions and investments to ensure the sustainableavailability of plant genetic resources in the pub-lic domain. As part of this process, they over-saw the collaborative development of ex situconservation and utilization strategies that de-fine key crop diversity collections and conser-vation/utilization needs within eight regions andfor each of 18 crops. In addition, the GCDT, incollaboration with the Government of Norway,

established the Global Seed Vault at SvalbardIsland, above the Arctic Circle, where seeds arebeing stored in chambers hollowed into a moun-tain in permafrost, as the ultimate backup for theworld’s gene banks (www.croptrust.org).

Facilitating use of gene bankcollections by generating andmaking available information

In order for breeders, researchers, or farmers toselect appropriate materials from germplasm col-lections, they need information about the var-ious samples and their characteristics, includ-ing the climatic and soil conditions associatedwith their collection sites, as well as the traitsof the cultivar itself. The degree of complete-ness and quality of data associated with sam-ples in gene banks varies among institutions.While some institutions have online databasesincorporating descriptions, photos, georeferencedata, and molecular data associated with sam-ples, other gene banks rely on noncomputerizedlists of samples. In most cases, “passport” data,the name of the sample and its origin, are rel-atively complete; but not all samples are ac-companied by the geographical coordinates oftheir collection sites, most samples lack charac-terization and evaluation data, and even fewerhave associated molecular characterization data(Khoury et al. 2010). Currently, some crops (i.e.,barley, banana, and coconut) have databases in-tegrating information about samples in multi-ple collections, and a few communities shareinformation about all the crops in their collec-tions. Overall, however, data are scattered andfragmented.

A major effort is under way to integrateand enhance existing information and create aglobal information system on gene bank sam-ples accessible from any PC through the WorldWide Web. A global information portal calledGENESYS is being developed through a partner-ship among Bioversity International, the GCDT,the System-Wide Genetic Resources Programmeof the CGIAR, and the Secretariat of the




International Treaty on PGRFA. This portal willintegrate information from the existing onlinecatalogue (SINGER) of more than 700,000 ac-cessions in the 77 collections held in the 11gene banks of the Consortium of CGIAR Cen-tres and the Asian Vegetable Research and De-velopment Centre (AVDRC); the EURISCO cat-alogue (http://eurisco.ecpgr.org/), which incor-porates data on 1.1 million accessions of 8650species in 1450 genera held in 38 European coun-tries; and the Germplasm Resources Informa-tion Network of the US Department of Agri-culture/Agricultural Research Service, whichhouses information on more than 510,000 dis-tinct samples in the National Plant GermplasmSystem of the United States. The goal of theGENESYS portal is to link collection man-agers/data providers with breeders, researchers,and other users, allowing users to search allcrop collections worldwide. Users will be ableto query and search using by combining fil-ters on the characteristics of accessions andthe environments from which they were col-lected; to select germplasm with the desiredtraits including resistance to drought, salinity,flooding, pests or diseases; and even to orderthat germplasm through the internet (Arnaudet al. 2010). The International Crop InformationSystem (ICIS; http://www.icis.cgiar.org) doc-uments germplasm geneologies/pedigrees andlinks this information with experimental obser-vations from evaluations undertaken in the field,greenhouse, or laboratory. ICIS has been de-ployed for crops including rice, wheat, barley,maize, common bean, chick pea, cowpea (Vignaunguiculata), sugarcane (various species of thegenus Saccharum), potato, sweet potato, and arange of vegetables (Portugal et al. 2007).

Most initiatives to use gene bank materialsto confront climate change focus on develop-ing new climate-resistant varieties with specifictraits to withstand drought and high temperature.Several CGIAR centers are exploring the pro-cess of identifying varieties preadapted to likelyfuture climates using a technique known as Fo-cused Identification of Germplasm Strategy. This

technique uses information about the environ-ment from which samples have been collectedto predict where selection pressures for adapta-tion traits may have occurred (e.g., Bhullar et al.2009). Recent efforts have sought to add georef-erence data for collection sites to samples in in-ternational collections. Basic research tools andGIS technology are available for determining theclimatic conditions at these locations. This infor-mation can be combined with climate projectionsto select germplasm from climatic analogs to fu-ture conditions. Breeders can then integrate otherdesirable traits into these preadapted cultivars.

The development of new crop varieties toensure food production in the face of climatechange will require new sources of genetic vari-ation combined with more efficient breeding andselection methods, for example, physiological,trait-based approaches rather than breeding foryield per se, to produce cultivars with higher tol-erance to the stresses projected to result fromclimate change (Ortiz et al. 2008). In order totake full advantage of existing gene bank col-lections, the samples must be characterized andevaluated with regards to traits important formanagement and breeding; then the data mustbe made easily accessible. To facilitate tappingthe many important traits for adaptation amongthe wild relatives of crops, molecular character-ization is needed, taxonomic misidentificationsmust be corrected, and ploidy must be deter-mined (Khoury et al. 2010). Unpredictable andvariable conditions and extreme events are pre-dicted to occur with increasing frequency. Thismeans resilience and variation within crops andvarieties, rather than the uniformity heretoforesought by breeders, will be crucial to reduce therisk of crop failures.

Selection for yield stability in stressed (lowyield) environments, which account for thelargest expanse of cultivated land, can providethe greatest opportunity for increases. This willrequire tackling major limitations on yield, suchas salinity, heat, and drought. To do so will re-quire increased understanding of the molecularbasis of key traits, expansion of phenotyping




and genotyping of germplasm collections, andthe development of new breeding strategies thatpermit introgression of multiple traits, as wellas ensuring communication and mechanisms fordelivery of material to breeders. New molecu-lar genetics tools permit the screening of largenumbers of varieties for specific traits, and for“mining” them for associated specific genes thatcan be bred into new varieties. New technolo-gies for breeding to address complex traits havebeen facilitated by new sequencing platforms,including marker-assisted selection, gene pyra-miding (creating durable resistance by select-ing for two or more resistance genes againsta pathogen), and marker-assisted recurrent se-lection, to bring multiple desirable alleles frommany sources into elite lines; genomic selectionto accelerate rates of genetic gain and breed-ing cycles; high-throughput technologies to de-termine the phenotypic components of complextraits (phenomics), bolstered by developments instatistical and modeling methods for the analy-sis of phenotypic data from field and controlledenvironment studies; expanding the germplasmbase in breeding programs using adaptive QTLs;and accelerating introgression and strategies forusing heterosis more widely to create hybridsfrom inbreeding species (Tester and Langridge2010). Because many developing countries lackthe facilities or human resources to apply thesetechniques, the CGIAR Centres joined forces toestablish the Generation Challenge Programme(GCP), a collaborative platform that brings to-gether their scientists and others at advancedresearch institutes and national agricultural re-search institutes in the developing world to applyadvanced molecular breeding tools to the collec-tions of the CGIAR gene banks in order to ad-dress the needs of poor farmers in the developingworld. The GCP focuses on addressing droughttolerance among crops that are most importantto food security in areas of poverty (Ribaut andButler 2004; http://www.generationcp.org/).

Some of the challenges farmers will facedue to climate change could be met throughthe identification and direct deployment, without

breeding, of landraces collected in an environ-ment and climate analogous to the predictedfuture climate where the vulnerable farmer islocated. Most farmers in the developing worldsave seeds from one harvest for the next season’splanting. Farmers commonly exchange seed withrelatives and neighbors in the same area (Davidand Sperling 1999). As environmental conditionsfor agriculture change, however, farmers willneed seeds from further afield, adapted to condi-tions different from those prevailing locally. Cur-rent systems of seed exchange among farmerswill have to be enhanced and expanded to drawfrom a range of materials appropriate to futureclimates. The distribution and re-release of ma-terials conserved in gene banks could contributeto this process. For example, the Ethiopian Na-tional Gene bank at the Institute of Bioversityand Conservation maintains a large collection,including 20,000 samples of barley and durumwheat (Triticum durum) from different agroe-cological areas in Ethiopia. The locations fromwhich these materials were collected, identifiedin the passport information associated with eachsample, can be used to define the climatic condi-tions under which the material was being grown.This information can be used to select materi-als adapted to projected future climates at othersites, which could be multiplied and distributedto farmers. In the face of climate change, manyfarming communities may lack awareness as tothe full range of options available for develop-ing adaptive responses to potential disasters suchas drought; they need to be provided with suchoptions, which can include combinations of sow-ing dates and phenology groups. Where new cli-mates exceed the known temperature or droughtadaptation limits of some crops, farmers mayhave to switch to more tolerant crops, such ascassava or drought-hardy Lathyrus. Promisingvarieties need to be evaluated by farmers in aparticipatory way to ensure that such varietiesmeet their needs. Experimental methods havebeen shown to be effective tools for understand-ing farmers’ preferences and their valuation ofdesirable traits (Smale and Drucker, 2007).




Interdependence

International exchange of genetic resources willbe crucial for adaptation to climate change.Countries have long been interdependent withregards to germplasm. For example, cassava,maize, groundnut (A. hypogaea), and beans,which originated in the Americas, became sta-ples in sub-Saharan Africa, while the indigenousmillets and sorghums of Africa are important inSouth Asia and Latin America. Widely plantedmodern varieties of most staple crops integrategenes derived from a pedigree of hundreds ofvarieties from different regions across the world.The globally popular VEERY wheat is the prod-uct of 3170 crosses involving 51 parents from 26countries (Palacios 1998 in Jarvis et al. 2009b).To adapt to climate change, many countries willneed to seek cultivars from other countries withcurrent climates that are analogous to those pro-jected to occur within their borders in the future.

Most of the world’s chronically hungry livein rural farm households in Africa and SouthAsia (Sanchez 2009). To evaluate the feasibil-ity of African countries’ obtaining germplasmpreadapted to future climates from within theirborders or from neighboring countries, Burkeet al. (2009) estimated overlap between presentand future climates within African countrieswhere climate change is expected to have ma-jor effects. The average overlap between a coun-try’s current range of growing season tempera-tures and its 2050 temperature range was 40%.Countries with a range of current climates due totopographic diversity had higher rates of overlapwith their future climates, including areas withintheir borders that had climates analogous to fu-ture projected climates elsewhere in the country.However, projections showed that 51% of coun-tries would need to seek germplasm from othercountries to adapt their agriculture to projectedfuture conditions (Burke et al. 2009). To obtainand use these genetic resources, countries willneed access to information about these cultivars,their traits, and the climatic and other environ-mental conditions under which they are currently

growing. In addition, they will need ways to ob-tain the germplasm itself—for subsequent test-ing, breeding, multiplying, and then distributionto their own farmers. Current climates in partsof Tanzania, Kenya, Cameroon, Nigeria, andSudan may serve as near-universal analogs forfuture climates in other African countries grow-ing maize, millet, and sorghum. Additional col-lections from these and other such countriesshould be a high priority in building gene bankcollections to facilitate adaptation to climatechange (Burke et al. 2009).

Genetic resources were moved around theworld quite freely until the Convention on Bi-ological Diversity recognized sovereign rightsto the biodiversity growing within a country’sborders, significantly dampening collection andexchange. A number of major collections, in-cluding those of the CGIAR Centres, AVRDC,and the Centro Agronomico Tropical de Inves-tigacion y Ensenanza (CATIE), are held in trustfor the peoples of the world under the auspicesof FAO; their materials can be tapped freely byusers in any nation. However, access by outsideusers to material held in national gene banksvaries from one country to another. The UnitedStates provides free and unrestricted distribu-tion of germplasm in their collections to allnations, but some national collections do not.Several policies and agreements have been for-mulated to provide a framework for the contin-uing exchange of plant genetic resources, mostrecently the International Treaty on Plant GeneticResources for Food and Agriculture (ITPGRFA),which came into effect in 2004. The Treaty pro-vides for multilateral exchange among the 120signatories, under a standard material transferagreement, of plant genetic resources of 36 cropslisted on Annex I of the Treaty, including mostcereals, legumes, roots and tubers, oil crops andfruits including banana, coconut, citrus spp. andapples (Malus domestica), as well as forages(Moore and Tymowski 2005). The implemen-tation of the ITPGRFA and the application of itsterms to other crops will be vital to adaptation toclimate change.




Conclusions

Climate change is projected to have a potentiallydevastating effect on agriculture, particularly inpoorer countries like those of Africa and SouthAsia, which already face chronic hunger. Supportfrom national and international agricultural re-search and development agencies will be crucialto help farmers obtain seed and other reproduc-tive materials of varieties and crops adapted tofuture conditions. The diversity of samples heldin the world’s gene banks will be vital to de-veloping these varieties. Additional collectionsare still needed to fill taxonomic, geographic, ortrait gaps in current collections and to ensure thatgermplasm from analogs to future projected cli-mates is conserved and made available to futureusers. Additional efforts are needed to conservespecies threatened by habitat destruction or cli-mate change, notably the wild relatives of crops.In addition, more attention needs to be paid tocrops including starchy staples like cassava andplantain (Musa balbisiana), which are criticalfor food security in areas projected to suffer themost. Investments will be needed to ensure thatcollections are not only complete but also wellmanaged, that needed research is carried out onconservation protocols and strategies, and thatcollected materials are characterized and eval-uated and information about them made avail-able. Capacity building will be needed to ensurethat countries in tropical and subtropical regions,where climate change impacts on agriculture areprojected to be most severe, are able to use thesematerials in breeding new varieties appropriate totheir needs, and that seed systems are understoodand supported so they can provide for the distri-bution of adapted varieties to farmers. Now, morethan ever, international exchange of germplasmmust be sustained, as many countries will need toaccess genetic resources not currently availablewithin their borders.

Fortunately, the potential benefits of such in-vestments are high: it was estimated, based onGreen Revolution increases in food production,that conserving 1000 samples of rice generated

an annual income stream for developing coun-tries with a direct use value of $325 million at a10% discount rate (Evenson and Gollin 1997 inFAO 2010). CGIAR research on maize, wheat,and rice alone, derived from tapping into the ge-netic diversity of those crops conserved in theCGIAR’s gene bank collections, has been cal-culated to have yielded annual benefits of > $1billion/year since the early 1980s (CGIAR Fund2011). The World Summit on Food Security hasdeclared a target of producing 70% more food by2050 to feed projected increases in world popu-lation. This will require that production increaseat a rate 38% greater than historical rates of in-crease, and be sustained for 40 years. This un-precedented increase will have to take place de-spite limited options for expanding the amountof arable land (Godfray et al. 2010); rising en-ergy costs (Tester and Langridge 2010); a declinein the availability of phosphorus (Cordell et al.2009); and a need to reduce emissions of NO2,a major greenhouse gas, of which the princi-pal source is agriculture, primarily fertilizer use(Tubiello et al. 2007). These increases in produc-tion must also be achieved against the backdropof the challenges to agriculture imposed by cli-mate change, not only the redistribution of cur-rent climates but also the disappearance of somecurrent climates and the appearance of novel cli-mates. If agriculture cannot increase productiondespite these constraints, millions of people willgo hungry. In light of these needs and challenges,the return on investments to expand, sustain, andmore effectively use genetic resources will begreater than ever before.

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Crop Adaptation to Climate Change (Yadav/Crop Adaptation to Climate Change) || Crop Germplasm Diversity: The Role of Gene Bank Collections in Facilitating Adaptation to Climate Change