TowardsaGlobalStrategyfortheconservationanduseofyam

In 2010, the Global Crop Diversity Trust (GCDT) commissioned the International Institute ofTropicalAgriculture(IITA)toleadthedevelopmentofaglobalstrategyfortheconservationanduse of yam, with a focus on the edible species. The goal is to share the responsibility ofmaintaininginperpetuityandinexsituconditionsarepresentativesampleoftheexistingyamdiversityand to facilitate theuseof thisdiversity for foodsecurity todayand tomorrow.Thedevelopmentofthestrategyinvolvedasurveyviaaquestionnairesenttotheholdersandusersof yam germplasm worldwide. Out of the 100 countries contacted (Fig. 1), 26 holders ofgermplasmreturnedcompletedquestionnaires(Table1,Fig.2).Basedonthesurveyoutcome,invitationstoattendatwo-dayexpertconsultationmeetingweresentto11countries(Bénin,Colombia, Côte d’Ivoire, Cuba, Ghana, Japan, Mali, Nigeria, Tanzania, Thailand, Togo, andVanuatu).Aworkinggroupof19yamexperts(9countryrepresentatives,9IITAscientists,and2Trust representatives) met in November 2010 at IITA, Ibadan, Nigeria. During the meeting,experts shared their knowledge and vision for the conservation and use of yam geneticresources.

PartIofthepresentdocumentShapingtheglobalstrategyfortheconservationanduseofyamreportsonyamconservationanduseandhighlights5 themes identifiedaspriority,basedonthe data captured during the survey and the expert meeting. For each theme,recommendationsweremade to address themain challenges facedby the conservationanduseofyamgeneticresources.ItpredominantlyreflectsandfocusesontheAfricansituationasinputsweremainlyprovidedbyAfricanpartners.Part IIpresentsIITA’sownconservationandusestrategyfortheinternationalcollectionofyam.AsIITAholdsthelargestcollectionandtheonlyonethatisinternational,theinstituteislikelytofurtherguidetheyamcommunityinthedevelopmentofglobalandconcertedinitiatives.

Figure1:Countriescontactedfortheglobalsurveyontheconservationanduseofyam.

Table1:Countriesandinstitutesthatprovidedinputviathesurveyquestionnaire.

Countries InstitutesBénin UniversityofAbomeyCalaviColombia UniversityofCordobaandCORPOICACostaRica UniversityofCostaRicaCôted'Ivoire CentreNationaldeRechercheAgronomique(CNRA)Cuba ResearchInstituteofTropicalRootandTuberCrops(INIVIT)DRC CentredeRecherchessurl'AméliorationGénétiquesdesPlantes(CERAG)FijiIslands KoroniviaResearchStationGermany LeibnizInstituteofPlantGeneticandCropPlantResearch(IPK)Ghana PlantGeneticResourcesResearchInstitute(PGRRI)Guinea InstitutdeRechercheAgronomiquesdeGuinée(IRAG)Japan Tokyo University of Agriculture; National Institute of Agrobiological Sciences; Ibusuki

BotanicalGardenKenya NationalGenebankofKenyaMali Institutd'EconomieRuraleNewCaledonia AICACentredesTuberculesTropicauxNigeria NationalRootCropResearchInstitute(NRCRI);IITAPhilippines PhilRootcropsTanzania KizimbaniAgriculturalResearchStation,ZanzibarThailand KhonKaenFieldCropResearchCenterTogo InstitutTogolaisdeRechercheAgronomique(ITRA)Vanuatu CentreTechniquedeRecherchesAgronomiquesduVanouatouVietNam PlantResourcesCenter

Towardsaglobalstrategyfortheconservationanduseofedibleyam

ContentsPARTI-Shapingtheglobalstrategyfortheconservationanduseofedibleyam

1. Introduction2. Prioritythemes

Theme1:YamconservationExsitucollectionsExsituconservationExsitucollectionerosionInsitugeneticerosionRecommendationsforTheme1

Theme2:YamdiversityRecommendationsforTheme2

Theme3:GermplasmhealthRecommendationsforTheme3

Theme4:Promotingtheuseofyamgermplasm,andthegenerationanddiffusionofinformation

GermplasmattractivenessGermplasmvisibilityGermplasmdiffusion

RecommendationsforTheme4Theme5:Capacitybuildingandawareness RecommendationsforTheme5

3. Conclusions4. References5. Annex(Surveydata)

PARTII-IITA’sstrategyforyam,2011–20201.Introduction2.Guidingprinciple3.Visionandmission4.Objectives1:Increasethediversityoftheinternationalcollection2:Furtherimproveconservationapproaches3:Identifyandtraceinternationalgermplasm4:Improvegermplasmuse6:Cleangermplasmforsafemovementanduse7:Exchangeknowledgewithourpartners5.Conclusion6.Acronymsandabbreviations

PARTI

Shaping the global strategy for the conservation and use of edibleyam

Authors:Dumet1D.,Lopez-Montes1A,Dansi2A.,Bhattacharjee1R.,Aboagye3L.M.,Lobo4M.A.,Ezebuiro5 C., Eke-Okoro5O, Barry6H., Kumar1 L., Coyne1D., Takagi7 H., Sirikul8 S., Girma1 T.,Kikuno1H.,Thiemele1D.,Gueye1B.,Selah9H.,Paganini10M.,Toll10J.

1InternationalInstituteofTropicalAgriculture,Nigeria2UniversityofAbomey-Calavi,Bénin3PlantGeneticResourcesResearchInstitute,Ghana4CorporacionColombianadeInvestigacionAgropecuaria,CORPOICA,Colombia5NationalRootCropsResearchInstitute,Nigeria6InstitutTogolaisdeRechercheAgronomique,Togo7JapanInternationalResearchCenterforAgriculturalSciences,Japan8KhanKainFieldCropsResearchCenter,Thailand9KizimbaniAgriculturalResearchInstitute,Tanzania10GlobalCropDiversityTrust,Italy

1. Introduction

Yam(Dioscoreagenus;family:Dioscoreaceae)isimportantforfood,income,andsocio-culturalevents. West and Central Africa account for approximately 93% of the world's annualproductionofanestimated51milliontonnes(t).ThedominantproductionzonestretchesfromCôted’IvoirethroughGhana,Togo,Bénin,Nigeria,Cameroon,Gabon,CentralAfricanRepublic,andthewesternpartoftheDemocraticRepublicofCongo.Thecropisalsogrowntoalimitedextent in several countries in East and Southern Africa and is important in Asia, northerncountries of SouthAmerica, aswell as the Caribbean and the South Pacific islands. Yam is amulti-species, clonally-propagated crop that is cultivated for its starchy tubers. Most of thecultivated species are dioecious, with separate male and female plants, although a few species aremonoecious.Of thetencultivatedspecies,D.rotundata,D.cayenensis,D.alata,andD.trifidaarethemostimportant.ThemajoredibleyamspeciesfromAfricaareD.rotundataPoir.(whiteyam, white Guinea yam), D. cayenensis Lam. (yellow yam, yellow Guinea yam), and D.dumetorum (Kunth) (trifoliate yam, bitter yam). Edible species from Asia includeD. alata L.(wateryam,greateryam),D.bulbiferaL. (aerialyam),andD.esculenta (Lour.)Burk. (Chineseyam,lesseryam).D.trifidaL.(cush-cushyam)isfromtheAmericasandD.nummulariaLam.isfromtheSouthPacific.

D.rotundataisindigenoustoWestAfrica;D.alataisindigenoustoAsiaandwasintroducedtoAfricaduringthesixteenthcentury.D.rotundata(2n=40chromosomes)andD.cayenensis(2n=60and80chromosomes)(alsoreferredtoastheD.cayenensis–rotundatacomplex)represent

an estimated 95% of global production. They have the highest market value owing to thesuperior suitabilityof their tubers for thepreferred fooduses for thecrop inWestAfrica.D.alata is themostwidely distributed species throughout the tropics (Asia, Pacific islands, theCaribbean,andLatinAmerica).Itincludesaccessionswith2n=40,60,and80chromosomes.Itsadvantagesincludehighyieldpotential,easeofpropagation(throughtheproductionofbulbilsand reliability of sprouting), early vigor forweed suppression, and long storability of tubers.These are valuable characteristics for sustainable production but the species has a majorlimitation in the field; most varieties are highly susceptible to a devastating foliar disease,anthracnose,causedbyColletotrichumgloeosporioidesPenz.

Yam (Dioscorea spp.) is particularly important for themillions of producers, processors, andconsumersinWestAfrica.About51milliontareproducedon4millionhaannuallyinthissub-region, mainly in five countries—Bénin, Côte d’Ivoire, Ghana, Nigeria, and Togo (Table 2).Annual increases in production, however, are due to increases in the area of land used forproduction, and not to improved productivity. Nigeria alone accounts for 68% of the globalproduction(35millionton3millionha).AlthoughNigeriaisthelargestproducerintheregion(becauseofthesizeofitspopulationofyamfarmers),moreyamisproducedpercapitainCôted’Ivoire, indicating that thecrop isamore importantcontributor to farmers’ incomes in thatcountry.

Table2:BasicstatisticsontheproductionofyaminWestAfrica,2008–2009.

Region/Country Area harvested(millionha)

Yield(t/ha) Production(milliont)

Percentageof worldproduction

Population(million)

Productionper capita(kg)

WestAfrica 4.44 10.83 48.1 92.99 291.27 165.1

Bénin 0.2 8.81 1.8 3.49 8.66 208.1

Côted'Ivoire 0.82 8.45 6.93 13.4 20.59 336.7

Ghana 0.3 11.87 3.55 6.86 23.35 152

Nigeria 3.05 11.5 35.02 67.69 151.21 231.6

Togo 0.06 10.2 0.64 1.23 6.46 98.8

World 4.93 10.5 51.73 100

Source:FAOSTAT,UpdatedDecember2009-AdaptedfromYIISWAprojectdocument.

2. PrioritythemesTheme1:YamconservationExsitucollectionsTheDioscoreagenuscomprisesover600species,thevastmajorityofwhicharetropical,withonly a few species extending into temperate climates. According to the 2010 report on thestateoftheworld’splantgeneticresources(FAO2010),15,903accessionsofyamarepresentlymaintainedinexsituconditionsin57countries(Fig.2).

Figure 2: Yam germplasm holders worldwide and number of accessions reported to bemaintainedinexsituconditions(FAO2010).

The questionnaire developed and sent to 100 partners for our own (IITA) survey capturedinformationfor7516yamaccessions,i.e.,approximatelyhalfoftheaccessionssurveyedbytheFAO report (Table 2). However, it complements the FAO data as some collections were notcaptured in the FAO records (Togo, Tanzania, and Mali). Worldwide, the most representedspeciesinexsitucollectionsareD.alataandD.rotundata(Table3).Asthesetwospeciesarethosemostcultivatedworldwide,theirpredominanceisexpected.However,itclearlyidentifiestheneedtocollectandstoreunder-representedspecies/diversity.Otherspeciesreportedinexsitucollectionsduringthesurveyareabyssinica,burkilliana,cirrhosa,doryphora,dumetorum,guineensis,hispida,liebrechtsiana,manganotiana,persimilis,preahensilis,preusii,quartiniana,sansibarensis,shimperiana,togoensis.

Table3:Numberofaccessionsandpercentageofthecollectionmaintainedinexsituconditionsperspecies.DataextractedfromFAO2010orfromtheyamglobalstrategysurvey.

FAOdata2010 SurveydataSpecies No. of

accessionsPercentageof thecollection

No. ofaccessions

Percentageofthecollection

D.alata 3904 24.5 2763 35.9D.bulbifera 334 2.1 164 2.1D.cayenensis 843 5.3 393 5.1D.esculenta 662 4.2 215 2.8D.nummularia 43 0.3 81 1.1D.opposita-japonica/japonica 118 0.7 20 0.3D.pentaphylla 68 0.4 65 0.8D.rotundata/rotundata-cayenensis 4208 26.5 3631 47.2D.transversa 2 0.0 10 0.1D.trifida 154 1.0 35 0.5Others/Unknown 5567 35.0 320 4.2

Details related to the collections surveyed within the development of the strategy arepresented in Table4. The largest collection is heldby IITAwith3170accessionsof 8 species(Table 5). Most of the germplasmmaintained in IITA is ofWest African origin (Fig. 3). Thisclearly shows the need to enrich the international collection with germplasm from otherregions,atleastfromAfrica.

Table 4: Number of accessions per surveyed country of the 10 most cultivated species. Da=alata; Db=bulbifera, Dc=cayenensis, De=esculenta, Do=opposite/japonica or japonica,Dn=nummularia, Dp=pentaphylla, Dr=rotundata, Dt=transversa, Dtr=trifida, Oth=Others orunspecified.

Countries Da Dbu Dca Des Do Dn Dp Dr Dt Dtr Oth TotalBénin 101 0 51 0 0 0 0 860 0 0 0 1012Colombia 64 8 16 16 0 0 0 32 0 16 8 160CostaRica 8 1 2 0 0 0 1 2 0 1 1 15Côted'Ivoire 233 5 16 5 0 0 0 212 0 0 58 530Cuba 100 2 7 2 0 0 0 4 0 1 0 116DRC 2 0 0 21 0 0 0 1 0 0 4 28FijiIslands 20 0 0 9 0 0 0 0 0 0 16 45Germany 3 4 1 0 0 0 0 0 0 1 20 29Ghana 105 15 20 15 0 0 0 159 0 0 78 392Japan 290 17 1 7 19 73 3 1 0 1 44 456Kenya 4 0 150 0 0 0 0 18 0 0 6 177Mali 45 15 45 0 0 0 45 0 0 0 0 150NewCaledonia 230 2 0 5 0 0 1 5 1 0 0 244Nigeria 46 0 13 7 0 0 0 66 0 0 0 132Philippines 28 3 0 11 0 0 3 3 0 3 3 54Tanzania 18 0 1 0 0 0 0 7 0 0 0 25Thailand 23 1 0 1 1 0 3 0 1 0 3 33Togo 30 6 2 2 0 0 0 107 0 0 5 150Vanuatu 320 8 8 24 0 8 8 8 8 8 0 400VietNam 125 1 1 68 0 0 1 1 0 0 1 198IITA 811 68 59 19 0 0 0 2139 0 0 74 3170

Table 5: Yam species and number of accessions maintained at IITA in the internationalcollection.

Species NumberofaccessionsD.alata 811D.bulbifera 68D.cayenensis 59D.dumentorum 53D.esculenta 19D.manganotiana 8D.preusii 10D.rotundata 2139

Figure3:GeographicoriginoftheinternationalcollectionofyammaintainedatIITA.

Exsituconservation

Today’soptimalconservationapproachforyamistheinvitroslowgrowthofmeristem-derivedseedlingswhich allowsmedium-term conservationwithminimum input (controlled light andtemperatureandone to two subcultures/year) (Dumetet al. 2007).However, yammeristemculture remains an obstacle in this in vitro conservation system as some accessions arerecalcitrant to existing procedures. IITA, in association with JIRCAS, are presently further

investigatingyammeristemingforuseasaconservationmethod.

At present, 39% of the curators maintain their germplasm in field-banks, versus 30% whomaintaininboth invitroandfieldgenebanks(surveydata).Cryobanking(conservationatverylow temperature, generally in liquid nitrogen) is not yet deployed for yam, although thisconservationapproachmaysoonbeareality.Indeed,varioussuccessfulprocesseshavealreadybeendescribed(MalaurieandTrouslot1996;Malaurieetal.1998;LeunufnaandKeller2003).Recent upscale trials performed at IITA showed a high level of cryo-tolerance for yamaccessions(Dumetetal.,inpreparation).Oncedomesticated,cryobankingwouldrequirejustaregularsupplyofliquidnitrogenandanoccasionalsampleregeneration,i.e.,itwillbecomethemosteconomicallyefficientoption for the long-termstorageofyam. IITA is furtherexploringyamcryopreservation in collaborationwith InstitutdeRechercheetdeDéveloppement (IRD)andwithsupportfromGCDT.

Exsitucollectionerosion

Oneofthemajorconcernsofgermplasmholdersistheerosionoftheirowncollection,whethermaintained in fieldor invitroconditions.This isoftendueto lowconservationstandards, forexample, inadequate light and temperature conditions of in vitro facilities from an erraticelectricity supply,or thebioticandabiotic stresses (nematodes, fungi,drought,viruses,etc.,)encountered in the field. When engaging in long-term conservation, financial supportmechanismsarenecessary tosecure themaintenanceandsafetyof thisgermplasm.For thatreason, national holders are encouraged to transfer their germplasm to genebanks ofinternational standard for the safe long-term conservation of their diversity. InWest Africa,yamgermplasm fromGhana, Togo, andBénin is currentlybeingduplicated for safety at IITA(through the projects on regeneration funded by GCDT). For other regions of the world,duplication hubs need to be identified. It was suggested that CATIE (Costa Rica) and/orEMBRAPA (Brazil) could play this role in Latin America as well the Secretariat of the PacificCommunityforOceania.

Thevarietalerosiontakingplaceinfieldgenebankscanbedecreasedwhentheyareestablishedinmultiple sites in the agro-ecological zones of adaptation.Where reliable funds are limitedandinvitroconservationisnotanoption,suchazonalgenebankapproachisencouraged.Itissuccessfullyused inBéninandJapan. In thecaseofBénin, thegenebanksweredevelopedatthecommunitylevelandhavetheaddedadvantageoffacilitatingthefarmers’directaccesstoanduseofgermplasm.

Varietal erosion can also take place due to mislabeling during storage. Such errors wereobserved in the IITA collection in both in vitro storage and in the field bank. To reduce thisrecurrentproblem,abarcodesystemavoidinghandtranscriptionhasnowbeenimplementedinIITA.Moreover,theidentityofeachaccessionisbeingverified.Thisinvolvesre-characterizingindividual accessions and matching their agro-morphological profile to the historicalcharacterizationdata.Oncevalidated,DNAordryleavesoftrue-to-typesampleswillbebankedwiththeappropriateaccessionreference.

Asmentionedabove,theheavypressuresongermplasmmaintainedinthefieldfrompestsanddiseasesalsoresult inerosionfromcollections.Basicculturaltechniques,suchaspropagationbyvinecuttingsortheuseoftargetedpesticideapplicationscanhelptomaintainlowlevelsofpests and diseases and their dispersion. Such technical practices are often neglected in fieldbanking(seeTheme3).

Insitugeneticerosion

On-going genetic/varietal erosion of yam is difficult to evaluate as there is no baselineinformationontheexistingdiversityandonlylimitedknowledgeonthediversitypresentlyheldinfarmers’fieldsorinexsitucollections.Themostsignificantfactorsofgenetic/varietalerosionreported by most germplasm holders are linked to agricultural development, i.e., thereplacement of yam landraces by elite varieties or other crops, loss of farms, changes infarmers’practices andmarketdemands.Climate change (drought, floods) andbiotic stresses(newdiseases)were also indicated asmajor eroding factors. Dr AlexandreDansi (Bénin) hasrecently carried out a systematic inventory of landracesmaintained by farmers in the zonalgenebanks. Such initiatives could be deployed in other countries/regions to monitor futurevarietal/geneticerosiontoguidetheprioritizingoffuturecollectionmissions.

InAfrica,yamismainlyusedasafoodcropwhileelsewhereintheworld,suchasinAsiaandLatinAmerica,itisusedasanadditiveingredientforfoodprocessing(asstarchinicecream,forexample), in snacks, and increasingly for pharmaceutical and other industrial applications.Generallythereisagrowinginterestinyam(surveydata)whichmayfurtherendangerdiversity,especially the diversity of wild yam. In Bénin, a unique population ofD. burkiliana is beingdestroyed (Dansi, personal communication). In Thailand, wild yam diversity was reportedendangered by the uncontrolled harvesting of the natural environment (the forest) and theexpansionofcommunities intonaturalhabitats(extensivehousingplans,replacementofyambyothercropsinthenewcommunities).Topreventanirreversibleerosionofthegenepool,thecollectionofbotanicseedsofwildspeciesshouldbeundertakenassoonaspossible.

RecommendationsforTheme1

1: Further collect and store yam diversity. If possible priority should be given toregions/countries from where samples have not yet been collected, and transferred to aninternationalcollection(e.g.,Madagascar,Ethiopia,andCameroon,inparticular)

2: Duplicate all unique accessions in genebanks with high-standard in vitro conservation topreventirreversibleloss

3:Identifyinternationalhubsforinvitrosafeduplicationandthesanitationofyamgermplasmattheregionallevelworldwide

4: Pursue the research on cryopreservation (especially germplasm stability followingcryopreservation)andimplementcryobankingforyam

5: Raise awareness on phytosanitary issues for stored germplasm and promote best culturalpracticestoreducepathogenpressuresinthefieldgenebank(seeTheme3)

6:Identifysustainablelocationsfortheestablishmentoftheyamcryobank

7:ValidatetheidentityofaccessionsinallcollectionsanddevelopDNAordryleavesbanksforappropriatereferenceandback-upinformation

8:Prepareinventoriesofthevarietaldiversitymaintainedbyfarmersatthenationallevelandinclude information related to farmers’ preferences and agro-ecological knowledge in theanalysis

9: Collectand storebotanical seedsofendangeredwildyam.The IUCNRedListmayhelp toprioritize species, at least at the global level. Collaboratewith institutes, such as Kew RoyalBotanicalGarden,tobenefitfromtheirknowledgeonyamseedstoragebehaviorandtheyamgenepool

10:Developconservationstrategiesatthenational leveltoavoidduplicationofeffortswithinthesamecountryandtohaveacommonvisionatthecountrylevel

Theme2:Yamdiversity

Generallythequalityofthepassportdataofthegermplasmmaintainedinexsituconditionsispoor (survey data). Moreover, the vernacular names of landraces are often a source ofconfusion as some genotypesmay have different names across different cultural or nationalboundaries,whiledifferentgenotypesmayhavesimilarnamesfromoneregiontoanother.Themajority of the germplasm holders have reported using the International Plant GeneticResources Institute (IPGRI)/IITA phenotypic descriptor list (survey data) to characterize theircollections.However, there is a great disparity in the number and type of actual descriptorsused per accession (only 30% use more than 20 descriptors). Further germplasmcharacterization isneeded formostex situ collections. In this regard, theuseof the recentlypublishedkeydescriptorsforyamgeneticresources isencouraged(HunterandBhattacharjee2009). Poor passport and characterization data impede an improved understanding of thediversitymaintainedinthevariouscollections.

Except in Bénin (Dansi, personal communication), the phenotypic diversity maintained byfarmershasyettobeanalyzed.Inthesamevein,thephenotypiccharacterizationofyaminexsitu collections has rarely involved farmers. Participatory characterization of yam should beencouragedforabetterunderstandingofyamdiversityinbothexsitucollectionsandfarmers’fields. Farmers’ knowledge will provide insight to validate yam descriptors generated fromscientificknowledge.Itisalsoimportanttolearnmoreaboutthediversitypresentlymaintainedby farmers in the different agro-ecological production zones and to understand why suchdiversityismaintained(farmers’preferences).Thiswillhelpinre-designingbreedingprograms

orientedtowardstheneedsoffarmersorotherusers.

Moleculartoolsaregeneratinghighlyvaluable informationforabetterunderstandingofyamdiversityandtorevealaccessions’uniquenessandtraits,i.e.,tofurtherrationalizeyamexsituconservation.Variousmolecularmarkers(EST-SSRsforD.alata,genomicSSRsforD.cayenensisand D. alata, D. prahensilis, and D. abyssinica) have already been developed by IITA/VSU,JIRCAS, and IRD, and are used by various institutes (Tostain et al. 2006; Narina et al. 2010;Mulunehetal.unpublished).ThesequencingofthewholegenomeofD.rotundataisunderwayin a collaborative project between JIRCAS and IITA with the objective of developing newgenerationmarkers, such as SNPs, for the constructionof linkagemaps, the identificationoftrait-specific QTL(s), and association mapping for marker-assisted selection in yamimprovementprograms.IITAisalsoinvolvedinanothercollaborativeprojectwithAustraliatodevelopDArTmarkersusingD.alataaccessions.Thedevelopmentofadditionaltools,suchasEST-SSRs, SNPs, and DArTs along with species-specific genomic SSRs, will soon allow theefficientassessmentofaccessionuniquenessandcollectiondiversity.

IITA, in collaborationwith12nationalprograms (Bénin,CostaRica,Côted’Ivoire, Fiji,Ghana,NewCaledonia,PapuaNewGuinea,Philippines,SolomonIslands,Togo,Vanuatu,andVietnam)and with financial support from the GCDT, is engaged in a molecular fingerprinting projectaimingat identifyingunique/duplicateaccessionswithinandacrossnationalandinternationalcollections.Atthatstage,molecularprofilesareanalyzedusingbothgenomicandEST-SSRs.

Molecular, phenotypic, and farmers’ indigenous knowledge are equally important. Theirintegrationwill revealyamdiversityandallowthedefinitionofcoreor trait-basedsubsetsatglobal,regional,ornationallevel.Inthecaseoftheinternationalcollection,acorecollectionof350 accessions was developed based on morpho-agronomic traits and passport data(Mahalakshmietal.2007). Thiscorewillneedregularrevisionasnewgermplasmisacquiredand included in the international collection (presently 500 entries are pending). Uniqueness,core,andsub-setinformationwillfacilitatethestratificationoftheglobalexsitucollection,i.e.,thelevelofsecurityrequiredforthemaintenanceofeachaccession.Forexample,atrulyrareaccessionwithmanybeneficial traitsof interestmaybemaintained inseveral locationsusingdifferent approaches (field, in vitro-, cryo- or seed-bank), while only one accession of aduplicatebatchwillbeconsideredforconservationinconditionsofmaximumsafety.

RecommendationsforTheme2

11: Implement participatory phenotypic characterization trials and integrate farmers’knowledgeingermplasmdescription.(Note:ThemodeldevelopedbyAlexandreDansicouldbeappliedtotoothercountries)

12:Furtherdevelopmoleculartoolstoexploreandbetterunderstandyamdiversity

13: Define core and trait based subsets at national, regional, or global level to increasegermplasmuse

14:Developastratificationstrategyforclonalcropsincollaborationwithotherclonalcollectionholders

15:Document/defineprimary,secondary,andtertiarygenepoolsforedibleyamspecies

16: Engage taxonomists from RBG Kew (Royal Botanic Gardens, Kew, UK) or other relevantinstitutesintheconservationstrategytoprovideadvice/informationrelatedtoyamtaxonomyandthegenepool

Theme3:Germplasmhealth

Germplasmhealthissuesareoftenneglectedinconservationsystemsdespitetheirimportanceintheconservationanduseofthegermplasm.Yamtubersareknowntocarryandaccumulatemany pests and pathogens (viruses, fungi, nematodes, insects, bacteria, etc.). As a result,collectionsmaintainedinthefieldcanreadilyturnintoareservoirofpestsanddiseases,withdamagingconsequencesontheviabilityofmaterial, futuregermplasmproduction,dispersionofpathogensanderosionofgermplasm.

Pathogensareasdiverseasthegermplasmthey infectandpathotypesvarygreatly fromoneregiontoanother.Asmentionedabove,culturalpracticescandrasticallyreducethepathogenload. For example, propagation by vine cuttingswill eliminate tuber infection by nematodesandhelptoeradicateothertuber-bornepestsanddiseases(providednewlyproducedcuttingsareplantedinnematode-freefields),whilepesticidetreatmentswillalsoreducetheoccurrenceof insects and fungi. However, elimination of viruses is difficult to achieve. Production ofplantingmaterialusingmeristematictissueinseveralhost-virussystemsresultedingenerationofvirus-freeplants.However,recentmeristemingperformedontheIITAfieldcollectioncouldnot eradicate the virus load from the plant tissues. Thermo-treatments, in particularcryopreservation,areunderinvestigationforimprovingyamsanitationandholdpromise.

Pathogenidentificationanddistributionaswellasreliablediagnosticsareessentialcomponentsforthesustainableconservationanduseofyamgeneticresources.Thereisnodoubtthatnewpests and diseases of yam are yet to be documented as diagnostic capabilities improve andactivitiesonyambroaden.Thespectrumofviruses infectingyam,forexample, isbroad,withbutafewaccuratelycharacterized(Kenyonetal.,2003).InUgandainEastAfrica,onlyrecentlythe causal agent of dry rot on yam was identified as a nematode species (Pratylenchussudanensis)differentfromthenematodepestthatcausesthesamesymptomsinWestAfrica(Scutellonema bradys) and the Americas (Pratylenchus coffeae and S. bradys) (Coyne et al.2003;Mudiope et al. 2008). The importance to productivity and quarantine status of newlyidentified biotic constraints then needs to be determined. As yambecomes popular in, or isintroduced to new geographic areas, so the possibility of new biotic constraints occurs. Thedocumentation of pests of quarantine importance is also the key to rationalize germplasmdistribution(toavoidunnecessarytestsandguaranteethosethatarenecessary).

Morethan82%ofthegermplasmholderssurveyeddeclaredthattheyusedanimportpermittobring foreign germplasm into their country (survey data). However, the general nationalcapacityforindexingandphytosanitationislow,i.e.,lessthan50%haveindexingproceduresinplace and only 50% regularly receive support from their national plant quarantine service.Indexing, as well as germplasm phytosanitation is a costly process. Moreover, germplasmhealthexpertise isoften lacking innationalprograms.Thedevelopmentofplanthealthunitsspecializedinmonitoringgermplasmforpestsandpathogens,protectionofgeneticresourcesand production of clean planting material should be encouraged at a regional level. TheGermplasmHealthUnit(GHU)atIITAisalreadyactingasaserviceforsuchhealthissueswithinAfrica.There isanurgentneedto identifyotherhubs inotheryamgrowingregions.Nationalprogramswhereindexingandcleaningcapacityalreadyexists(e.g.,Colombia,Cuba,CostaRica,andBrazil)shouldbeencouragedtoprovidesucharegionalservice.

RecommendationsforTheme3

17: Assess pest risk to classify yam pathogens (viruses) as regulated or non-regulatedquarantinepests

18:Developprotocolsfortheproductionofvirus-freeplantingmaterials,usingcryotherapyinparticular

19: Develop simple and cost-effective diagnostic tools for the rapid assessment of in vitroseedlingsandsafegermplasmexchange

20:Createawarenessabouttheneedforsafeconservationanddistributionofyamgermplasm,andbuildcapacitytosafeguardvaluablegermplasmfrompestsandpathogens

21:Promotethedevelopmentofregionalhubsforvirusindexingandgermplasmsanitation

Theme4:Promoting theuseof yamgermplasm,and thegenerationanddiffusionofinformation

Germplasmattractiveness

To date, only a small proportion of the international collectionmaintained at IITA has beenused in yam improvement programs, and this is evident from the distribution of just 1077accessions(fromatotalcollectionof3170accessions)inthelast10years(surveydata).Littleinformation was captured about the distribution patterns in national collections during thesurveybut thesituation is likely tobesimilar, ifnotworse.Thismaynotbesurprising,giventhatyamproductioninWestAfricalargelyremainswithfarmers’varieties/landraces,withlittleyam breeding activity underway. In terms of access to and the use of germplasm, theparticipatory zonal genebanks established in Bénin are the most efficient system. In thisparticular case, farmers are involved in the collection process for assemblage, thus having

directaccesstoyam.

Theregulationsongermplasmsanitationandimportcurrentlylimitthemovementanduseofyam germplasm (non-clean material) in the international collection. To date, efforts havemainly focused on describing diversity based on “academic” agro-morphological descriptors,whichhavesomewhatneglectedtraitsofmoreinteresttouserssuchasbreeders.Collectionsneed urgent screening for traits such as pest and disease resistance, aswell as drought andflood tolerance. Other traits, including taste, cooking properties, techno-functionalcharacteristics and postharvest behavior, are alsomissing from the existing characterizationdata. Asdescribedabove,germplasmcharacterizationshould involvefarmersorcommunity-based germplasm holders. Moreover, for industrial and pharmaceutical applications, theprivate sector should be encouraged to engage in collection characterization (starch quality,secondarymetabolitecontent,etc.).

Germplasmvisibility

Anotherfactorlimitinggermplasmuseisthevisibilityandaccessibilityofinformationrelatedtothe collections. In the case of the international collection maintained at IITA, passport andcharacterization data are available on line (http://www.iita.org/genetic-resources-center) inaddition to other systems, such as SINGER (http://sgrp.cgiar.org) and soon GENESYS(http://www.genesys-pgr.org/). Information related to accessions entering the internationalcollectionforsafeduplicationpurposeswillbeuploadedontheseCGIARandglobalinformationsystems.Theacknowledgementtothedataproviderandtheresponsibilityfortheinformationso provided were discussed during the consultation. Arrangements should be made in thedatabasetoacknowledgedataprovidersandidentifytheresponsibilityforupdatingthedata.

Germplasmdiffusion

Ninetypercentofnationalgermplasmholdersdistributegermplasmdirectlytofarmers(Surveydata), comparedwith less than1% fromthe international collection.That reflects thecriticalrole of national programs in diffusing germplasm to farmers, and is probably amuch higherfigure than formost seed crops. According toAlexandreDansi, a lot of diversity available ingenebanksdoesnotreachfarmers.Effortsshouldbemadetotransferthediversitytofarmers.This couldbeachievedby thedistributionof the core collectionor trait-based subsets (oncedeveloped) to national programs and/or farmers. This implies the regular characterizationofnewly acquired germplasm following a minimum set of descriptors under standardenvironmentalconditions.Anotherapproachtoincreasefarmers’accesstodiversitywouldbeto invite farmers to research institutes to enable them to have direct access and improvedawarenessofnewtechnologies,varieties,orcropsandtopromotethediffusionofgermplasmthrougheventssuchasfielddays.Suchfielddaysthatalsoinvolvetheprivatesector(e.g.,agro-input producers or suppliers) as sponsors have proved very successful in Thailand. Similarly,farmerscouldbeinvitedtovisitfieldconservationplotsmaintainedasinternationalcollectionsat IITA.This latteroptionhasnotbeenwelcomedbyallexpertsparticipating in themeeting,however,assomebelievedthatcommunicationproblemsmightreducetheexpectedimpact.

Only a fewnational programs are fully functionalwith regard to indexing and sanitation butmany of them have in vitro facilities that can punctuallymass-produce yam seedlings (evenwhenfacingdifficultiesinrunningalong-term,reliableconservationfacility).Systemsallowingthe movement of clean germplasm from a germplasm health hub to national plant tissueculturefacilitiesshouldbedevelopedtofacilitateusers’accesstocleangermplasm.Wheretheplanttissueculturetechnology isnotavailable, thedeploymentof thevinecuttingtechniquemay help in increasing the distribution of cleanmaterial. Indeed, vine cutting performed onmeristem-derived invitroplantsshowedhigherratesofmultiplicationandcanbemaintainedfreeofpathogens ifmultipliedundercontrolledconditions in thescreenhouse (Kikunoetal.2007;Coyneetal.2010).

RecommendationsforTheme4

22: Evaluate accessions for traits of immediate interest for farmers/breeders and new uses(industrial,pharmaceutical)

23: Promote and implement farmer-participatory evaluation to enrich information on aninternational/regional/nationaldatabase

24:Upgradeonlinedocumentationtoolstoacknowledgeandidentifydataprovider

25:Promoteappropriatetechniquesforyampropagationsuchas invitropropagationorvinecuttingstoaddresshealthissuesandincreasesafegermplasmdistribution

26:Organizefielddaysatnationalinstitutestopromotenewtechnologiesandvarieties

27: Provide farmerswith theopportunity to visit the international collections or assess theirdiversity

Theme5:Capacitybuildingandawareness

Very fewscientistsarededicated toyamresearchworldwide.There isaneed to trainyoungstaffinthefieldofconservationandtheuseofyamgeneticresources.IITAisregularlyinvolvedin such trainings but preferably targets candidates who are already employed by a nationalinstitute and able to apply their newly acquired knowledge directly. Field and in vitroconservation manuals were recently developed and are available athttp://www.iita.org/genetic-resources-center as well ashttp://cropgenebank.sgrp.cgiar.org/http://cropgenebank.sgrp.cgiar.org/.

SeveralAfricancountriesareconcernedwithregardtocapacitybuildingandthereplacementofscientistsinvolvedinyamresearch.Theriskoflosingnewlytrainedstaffishigh.Workingonother crops is often more attractive because of greater funding opportunities. Jointinternationalprojectsinthefieldsofbreeding,conservation,andthevaluechainareneededtoraise the profile of yam and attractmore funds. Involving the private sector should also be

considered.Pleadingfortherecognitionofyamresearchathigherdecision-makinglevels,suchasatECOWASforWestAfrica,isalsotobeconsidered.However,suchadvocacyisdifficulttotackle.

RecommendationsforTheme5

28:Postgraduatetraininggrants(MScorPhD)shouldbesecuredtotrainfutureyamscientists.Suchstudentshipsshouldalsobebondedtothenationalprogramtoavoidthe“braindrain”,atleastforafewyears

29:Wheneverpossible,thepotentialvalueofyamshouldbebroughttotheattentionofpolicy-makersandotherhigh-poweredgroupsatnational,regional,andinternationallevels

3.Conclusions

The success of the conservation and use strategy for yamwill depend on the diversity andcommitment of the partners engaged, including donors, and the demands from the privatesector. So far, 26 countries have provided input to the present document, i.e., at least 26partners are engaged in the strategy. It is important to keep a nucleus of active partners tofurtherengageothers.Thiswillhappenonlyifthedemandforyamincreases,theprivatesectorisinvolvedinsettingprioritiesandimplementingyamconservationanduse,common(regional)projects are developed, and the differentworking groups have pathways for communicatingtheir respective progress. At that stage, 29 action priorities were identified by the group toshapetheglobalstrategy.Thegrouprealizedthatsomecrucialpointswereyettobeidentifiedandthusfurtherfeedbackiswelcomed(contactddumet@cgiar.orgortoll.jane@croptrust.org).Action is already ongoing to address someof the recommendationswith the support of theGCDT, national programs, and IITA.Others priorities need the initiationof newprojects, i.e.,newsourcesoffundingandmoreprivatesector-orientedparticipation.Asobservedduringtheexpertmeeting,thecriticalmassofscientistsworkingonyamislimitedandthoseengagedinsome yam research activities are not dedicated to these full-time. For this reason, anddepending on initiatives, yampartners should be linkedwith other communitiesworking onsimilar issues. For example, the implementation of regional platforms will be viable only ifdeveloped with a ‘multiple crops’ focus, i.e., if partners working on other clonal crops areengagedinthestrategy.IITAispresentlytheonlyinstituteholdinganinternationalcollection,and as such plays a critical role in the long-term conservation of yam biodiversity and thesustainable use of yam genetic resources. IITA’s own strategy, described in part two of thepresentdocument,canprovideguidancefortheglobalsystem.However,nationalandregionalstrategies,definedmorebroadlyforclonalcrops,areneededtomatchandbeintegratedtothepresentdocumentforglobalactiontostart.

Thepresentdocumentwill be circulated tousers andholdersof yamgermplasmworldwide.Weencouragepartnerswillingtoprovidefeedbackand/orengagedinthestrategytocontactIITA (ddumet@cgiar.org; a.lopez-montes@cgiar.org) or GCDT (jane.toll@croptrust.org). Inparticular,wewelcomeinformationrelatedtoexsitucollectionsofyam(thosenotreportedin

the present document), examples of yam genetic erosion, as well as strategy documentsdevelopedatcountryorregionallevel.

4.References

Coyne,D.L.,L.A.H.Talwana,andN.R.Maslen.2003.Plant-parasiticnematodesassociatedwithrootandtubercropsinUganda.AfricanPlantProtection9:87–98.

Coyne,D.,A.O.Claudius-Cole,andH.Kikuno.2010.Sowingtheseedsofbetteryam,CGIARSP-IPM,TechnicalInnovationBrief,No.7.Sp-IPM,IITA,Ibadan.Nigeria.

Dumet D., O. Ojuderie, and A. Adeyemi. 2007. IITA Genebank Manual Series, Yam in vitrogenebanking.IITA,Ibadan,Nigeria.

FAO.2010.ThesecondreportontheStateoftheWorld’sPlantGeneticResourcesforFoodandAgriculture.FAO,Rome,Italy.

Hunter,D.andR.Bhattacharjee.2009.Keyaccessandutilization:descriptorsforyamgeneticresources.www.bioversityinternational.org

Kenyon,L.,Shoyinka,S.A.,Hugehes,J.d’A.andOdu,B.O.2003.AnoverviewofvirusesinfectingDioscoreayamsinsub-SaharanAfrica. In,Pages423-439,Plantvirologyinsub-SaharanAfrica:proceedingsofaconferenceorganizedbyIITA,4-8June2001,Eds.J.D’A.HughesandB.Odu.IITA,Nigeria.Kikuno,H.,R.Matsumoto,H.Shiwachi,H.Toyohara,andR.Asiedu.2007.Comparativeeffectsofexplantsourcesandageofplantonrooting,shoot,andtuberformationofvinecuttingsofyams (Dioscorea spp.). Japanese Journal of TropicalAgricultureVol. 51, Extra issue2: 71–72.102ndMeetingoftheJapaneseSocietyTropicalAgriculture,Miyazaki,Japan.

Leunufna,S. andE.R. J.Keller.2003. Investigatinganewcryopreservationprotocol foryams(Dioscoreaspp.).PlantCellReports21(12):1159–1166.

Narina Satya, A.M. Sartie, P.L. Montegue, R.S. Asiedu, M.I. Ali, and R.H. Mignouna. 2010.Informativemicrosatellitemarkersforyam(DioscoreaalataL.)fromExpressedSequenceTagsofheterologousspecies.(SubmittedtoISRC.)

Mahalakshmi,V.,Q.Ng,J.Atalobhor,D.Ogunsola,M.Lawson,andR.Ortiz.2007.DevelopmentofWestAfricanyam(Dioscoreaspp.)corecollection.GeneticResourcesandCropEvolution54(8):1817–1825.

Malaurie,B.andM-FTrouslot.1996.Cryopreservationofinvitroyam(Dioscoreasp.)apicesby

the encapsulation-dehydration technique. Abstracts, p 252. Eucarpia, Meeting on TropicalPlants,11–15March1996,France.

Malaurie,B.,M-FTrouslot,N.Chabrillange,andF.Engelmann.1998.Survivalandrecovery inyam (Dioscorea spp.) after a simple cryopreservation process. In: JIRCAS/IPGRI JointInternational Workshop: Cryopreservation of tropical plant germplasm Current researchprogressandapplications,20October1998.Tsukuba,Japan.

Mudiope,J.,P.R.Speijer,D.Coyne,R.N.Maslen,andE.Adipala.2008.AssociationofMeloidogynespp.andPratylenchussudanensiswithpostharvestdamageonyam(Dioscoreaspp.)inCentralandEasternUganda.AfricanJournalofCropScience15:93–99.

Tostain,S,N.Scarcelli,J.Brottier,J-LMarchand,J-LPham,andJ-LNoyer.2006.DevelopmentofDNA microsatellite markers in tropical yam (Dioscorea sp.). Molecular Ecology Notes, 6 (1):173–175.

5. Annexes(Surveydatainpowerpointadded)

PARTII

IITA’sYamStrategy,2011to2020

PROPOSED: Authors:Dominique Dumet, Antonio Lopez-Montes, Ranjana Bhattacharjee, andLavaKumar

Contributors:DannyCoyne,HidehikoKikuno,GezahegnTessema,BadaraGueye,andThiemeleDeless

1.Introduction

ThenewIITAstrategy2011–2020states:“inadditiontoitsfundamentalroleofcollectionandconservation, the Institute will expand its role in utilization of these genetic resources tosupportitsownbreedingprogramsandthoseofitspartners.Itwillexplorethegeneticwealthofthesepreciousgenebankholdingstohelpnationsrespondtonewfoodneedsandbiologicalthreats,aswellasadapting toclimaticandenvironmentalchanges (drought tolerance,pests,soil erosion, human preferences, etc.). Many tropical countries stand to benefit from thegeneticresourcesofothertropicalnations,iftheseresourcescanbeeffectivelymanagedandshared; such intra-tropical interdependence will undoubtedly increase under climate changeandwithitthenecessityofimprovedcollaboration,conservation,andtheuseofcropgeneticdiversity.IITAcanplayacentralroleinfacilitatingthiscollaborationandprovidingastablebaseforongoingefforts”.

Atpresent, IITA’sGeneticResourcesCenter istheonlygenebankmaintaininganinternationalcollectionofyam.Assuch, it isplayingakeyrole intheconservationanduseofyamgeneticresources. This international collection,maintained in trust under the auspicesof theUnitedNations,isthelargestexsitucollectionworldwide,withover3000accessions.However,thereisbroadagreement,asdepictedintheIITA2011–2020strategyabove,thatmorebenefitcouldbederivedfromthiscollectionandfromIITAasawhole.Tothisend,andasacomplementtotheglobalconservationandusestrategy,theIITAyamstrategywasdeveloped.

2.GuidingPrinciple

Explore the wealth of IITA’s genebank holdings to help nations respond to increasing foodneedsandbiologicalandabioticthreats,aswellasadaptingtoclimateandculturalchange

3.VisionandMission

Consistentwith IITA’smission, the yam strategy for the period 2011–2020 seeks to find solutions tohunger and poverty via the increased access for farmers, processors, researchers, and the extensionservicestothegeneticdiversityofyamspecies

4.Objectives

1:Increasethediversityoftheinternationalcollection

• The international collection of yam maintained by IITA has its limitations, i.e., thegermplasm is exclusively from West Africa and one species, D. rotundata, is overrepresented (67%). A fraction of the existing yam diversity is captured in theinternationalcollection.

The IITA yam strategy calls for efforts to enrich the collectionwith African yamdiversity,including wild relatives. This will be achieved in association with national programs viacollectionmissionsand/ortransfersfromnationalcollections.Institutes,suchasKewRoyalBotanicalGarden,willbesolicitedtosharetheirknowledgeoftheyamgenepoolandhelpindraftingaprioritylistfortheacquisitionofwildspecies.IITAsupportstheideaofdevelopingat least two other international platforms dedicated to clonal crop conservation anddiffusionintwootherregionsoftheword(AsiaandAmerica)toservetheyamcommunity.

2:Furtherimproveconservationapproaches

• Today’soptimalconservationapproachforcultivatedyamistheinvitroslowgrowthofmeristem-derivedseedlingswhichallowsmedium-termconservation(12–24months)ofgermplasm.Someaccessionsarerecalcitranttothestandardmeristemingprocess.Theestimate annual cost of maintaining the international collection is US$28/accession.Ultimately, cryopreservationwill provide a longer-term conservationmethod and thecheapestoptionforyamgermplasm.ForDioscoreawildspecies,long-termconservationintheformofbotanicalseedsisalsoforeseen.

IITA will further investigate yammeristeming as well as cryopreservation via the dropletvitrificationprocess.Thesustainabilityofcryobankingyaminthe IITA-Ibadanenvironmentwill also be analyzed. Germplasm stability following in vitro storage (includingcryopreservation) will be investigated. Botanical seed storage will be initiated for wildspeciesofyam.

• At present all accessions of the international collection aremaintained in the field (3tubers/accession) and 35% of them are duplicated in vitro (5 seedlings/accession). Inaddition,approximately40%ofthe invitrocollectionisyearlytransferredtoBéninforsafeduplication.

IITAwillstartstratifyingtheinternationalcollection,i.e.,reviewingtheconservationoptionforeachaccession: field-and/or invitro-and/orpossibly sooncryo-and/or seed-banking.Thestratificationwillbebasedmainlyonthecomparativerarityofanaccession(seebelow),cryotolerance,invitrogrowthrate,andhealthstatus,aswellasusers’preferences.IITAwillfurtherinvestigatemassproductionforthefasterdeliveryofrobustinvitroseedlings.

• Ongoing insitu conservationstrategieswithyamandothercropsareconsideringasacomplementarystrategyinvolvingfarmers’knowledgeandagro-ecosystemevolutiontocontributeintheconservationprocess.

IITAwillencouragethebackstoppingof institutionsofthenationalscienceandtechnologysystems to implement community based conservation and use projects, linking farmers’diversity,theIITAgenebank,andbreedingprograms.

3:Identifyandtraceinternationalgermplasm

• Accessionpassportdataareoften limited.Asa result,duplicateshaveaccumulated intheinternationalcollection.Inthesameway,samplemislabelinghasledtothelossofvaluablegermplasm.Duplicatesandmislabeledaccessionsunderminetheconservationeffort, i.e., low priority samples are maintained to the detriment of those not yetrepresentedand/ormorevaluable.

IITAwillfurtherworkonmoleculartooldevelopmenttooptimizegermplasmmanagement,i.e,accession identification, rarity, and traceability. These toolswill alsohelp to set apriority forcollectingmissions/acquisitions. JIRCAS,which isan institutionalreadycollaboratingwith IITAon yam genome sequencing, is foreseen as a major partner. It is expected that closecollaborationwith other institutes, such as IRD,will be developed, to share and benefit fromrespectiveknowledge.Aftersequencingtheyamgenome,IITAwillbeconservinggenesaswellasaccessions.

4:Improvegermplasmuse

• Agro-morphologicalandpassportdataareavailableformostyamaccessionsmaintainedin the international collection. In contrast, evaluation data which are of immediateinterest for users are often missing. The diversity of the international collection hasbeenestimatedusingpassportandagro-morphologicaldataonly.

IITA will further engage in germplasm evaluation to better fit users’ needs. IITA will leadparticipatory evaluation trials and the techno-functional characterization of the internationalcollections. This work, linked with Objective 3, will generate information for geneticimprovementvialinkagemapping,theidentificationofQTLs,associationmapping,andmarker-assisted selection. Farmers and national programs, institutions in the science and technologysystem,andindustrywillplaykeyrolesinthismissionaspartnersorasco-financers.

• Passport and characterization are the main data presently available to users. Thisinformation is accessible on line on IITA web site (http://www.iita.org/genetic-resources-center)aswellasonothersystemssuchasSINGER(http://sgrp.cgiar.org)andwillbesooninGENESYS(http://www.genesys-pgr.org/).

IITA will carry on its effort on centralizing and making available newly generated data anddispatchinginformationtoglobalinformationsystemsforthebenefitoftheyaminternationalcommunity.Anon-linecatalogofelitenewcloneswillbeavailabletoo.

5:Cleangermplasmforsafemovementanduse

• The distribution of yam from the international collection is limited because of theaccumulation of viruses of quarantine importance in the germplasm. This is a majorphytosanitarybarriertotheinternationalexchangeofyamgermplasm.Availableinvitrotissuecultureproceduresarenoteffectiveingeneratingvirus-freegermplasm.

IITAwillfurtherinvestinyamgermplasmsanitationresearch.Cryo-therapy,inparticularwillbetested for clean seedling production. Effortswill also be focused on developing efficient virusindexingtechniquestoguaranteethesafeconservationanddistributionofgermplasm.

6:Exchangeknowledgewithourpartners

• Nationalinstitutionsforscienceandtechnology,advancedresearchinstitutes,farmers,and IITAhavedifferentamountsofknowledge related to theconservationanduseofclonalcrops.Whetheracademicorancestral,allknowledgeisvaluableandneedstobeaccessibleandexchanged.Privatesectorandindustryhavethepotentialtocontributetoevaluation.

IITAwillcontinuetobuildcapacityinthefieldofbiotechnologyappliedtotheconservationanduse of yam. Efforts will be augmented to increase knowledge exchange among partners tobetterservetheyamcommunity.Food,feed,medicinal,andotherindustrieswillbeengagedintheevaluationofyamgeneticdiversity to increaseknowledgeand,demandandsomake thepotentialofyamareality.

5.Conclusion

The conservation strategy 2011–2020 for yam at IITA aims at maintaining in perpetuity theinternationalcollectioninharmonywithworldwidepartnersinvolvedinyamconservation,andpromotesitsuseasaninternationalpublicgood.ThestrategywillbuiltonIITA’sexperienceandexchangewithpartners.

Thisstrategyprovideselementstointegratebiotechnologyandnaturalresourcemanagementstrategies in a complementary effort to raise the profile of yam at the national andinternationallevels.

6. AcronymsandabbreviationsCATIE TropicalAgriculturalResearchandHigherEducationCenterCGIAR ConsultativeGroupforInternationalAgriculturalResearchCORPOICA CorporacionColombianadeInvestigacionAgropecuariaECOWAS EconomiccommunityofWestAfricanStatesEMBRAPA EmpresaBrasileiradePesquisaAgropecuariaGCDT GlobalCropDiversityTrustGHU GermplasmhealthUnit(IITA)IITA InternationalInstituteofTropicalAgricultureIPGRI InternationalPlantGeneticresourcesInstituteJIRCAS JapanInternationalResearchCenterforAgriculturalSciencesIRD InstitutdeRechercheetdeDéveloppementVSU VirginiaStateUniversity