R4D Review Issue No. 6 (March 2011)


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In this issue: Plant health is an important concern for all. IITA believes that ensuring plant health is pivotal to improve agricultural productivity and food security, and reduce poverty. It is also a key element in IITA’s strategy of intensifying sustainable agriculture. Containing biological threats, among other things, to food security is the real national defense, says IITA DG Hartmann.

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  • To ensure Food Security in Sub Sahara Africa, Plant Health matter needs emmidiate attension. Elimination of plant viruses by Diagnosis techniques, Meristem tip culture and PCR are integral.........
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R4D Review Issue No. 6 (March 2011)

  1. 1. R4D Review Issue 6, March 2011 Climate change and plant health Healthy banana tissue culture industry Safe exchange of germplasm Germ-free germplasm In Kanti Rawal’s footsteps Restoring the IITA Forest Investing in aflasafeTM Clean seed systems: Banana, cassava, and yam A hot bath for the suckers! Novel surveillance system Transgenic banana for AfricaResearcher inspecting soybean seeds forpathogen cultures. Photo by J. Oliver, IITA. www.iita.org
  2. 2. contents2 EDITOR’S NOTE Plant health matters 4Nigeria gets improved Plant health is an important concern cassava for all. IITA believes that ensuring plant Better soybean health is pivotal to increase productivity and in its strategy of sustainable Conference on agriculture intensification. Containing humid tropics biological threats, among other things, UPoCA gives to food security is the real national farmers a lifeline defense. Liberia and Ghana to6 REVIEW Climate change and plant health 6 develop agriculture Agriculture has been pinpointed as one of the factors contributing to climate change. This article discusses what research the CGIAR centers, including IITA, are doing to cushion the negative impacts of climate change.12 FEATURES Towards a healthy banana industry in East Africa 12 Banana production in East Africa has been riddled with problems, including pests and diseases. IITA scientist Thomas Dubois did a SWOT analysis to determine what ingredients are needed for the banana tissue culture industry to succeed. GHU: Gateway for the safe exchange of germplasm 19 IITA’s Germplasm Health Unit is delivering a critical function. Virologist and GHU Head Lava Kumar walks us through the important work being undertaken to ensure the safe exchange of international public goods. Conservation of germ-free germplasm 26 Conserving clean genetic resources for agricultural sustainability and the preservation of diversity is imperative if we want to ensure global food security. In Kanti Rawal’s footsteps 28 Kanti Rawal, IITA’s plant geneticist in the 1970s, traveled 38,000 km around Nigeria and Niger to collect wild and domesticated accessions of cowpea. The authors—Remy Pasquet, Dominique Dumet, and Sunday Aladele—tell how they did the same almost 40 years later and came up with the same conclusions. Restoring the IITA forest 33 The IITA forest is an Important Bird Area, refuge, and a critical pocket of biodiversity in Nigeria and in the region. Read how the IITA-Leventis forest restoration project in Ibadan is promoting and raising awareness about forest conservation.36 BEST PRacTicE Investing in aflasafeTM 36 Commercial production of a simple biocontrol product called aflasafe™, developed by IITA and collaborators, may be the solution to the recalcitrant problem of aflatoxin contamination in important food products, such as maize and groundnuts.
  3. 3. Clean seed systems: banana, cassava, and yam Clean yam seed tubers from vine cuttings 43Production and distribution of clean planting materials Plant Physiologist Hidehiko kikuno describes theof banana and plantain 38 new technology of producing yam seed tubers.Banana is a staple eaten by millions of Africans. in this The technology combines growing vine cuttings onarticle, Banana/Plantain Breeder Bi irie Vroh explains carbonized rice husks and in vitro micropropagationhow iiTA produces clean planting materials of banana (tissue culture). it is quick, cost-effective and resultsfor distribution to partners. in clean planting materials.Developing clean seed A hot bath for the suckers! 46systems for cassava 41 Production of banana andCassava is the most widely plantain, important food crops,cultivated of all vegetatively- is constrained by pests andpropagated crops. Virologist diseases, such as nematodesJames legg discusses how and weevils that lead to annualiiTA and partners have put in losses of millions of dollars. iiTAplace a rigorous new system scientists have devised an easycalled Quality Management method of killing nematodes inProtocol to assure the health banana suckers—immersingof cassava planting material. them in boiling water for 20-30 seconds!48 DEWN: adiseasesurveillance system for cassava novel 48 A multipartner team of scientists havetool box developed an early warning system that uses cell phones to monitor and track cassava disease outbreaks in Tanzania, and now in Rwanda.54 who’s who 59 lookiNg iNDavid Chikoye: NAQS: iiTA contributes to our effectiveness 59Think of the big picture 54 CoMESA: Ensuring sanitary and phtosanitaryJim gockowski: standards in the region 62Intensification of agriculture is analternative to deforestation 56 iAPSC: Protecting Africas plant health 6670 f R o N T i E R STransgenic banana for Africa 70Molecular geneticist leena Tripathi provides an update ona collaborative work to develop a high-value product—thetransgenic banana. The use of transgenic technologiesfacilitates the transfer of useful genes, such as those fordeveloping resistance to banana Xanthomonas wilt. 1
  4. 4. EDiToRS NoTEPlant health mattersEfforts by national and international intensification2. The compelling reasonresearch systems during the last two for this is that biological threats, such asdecades have contributed to nearly diseases, pests, and weeds are directlydoubling the production of major staple responsible for reducing crop yields byfoods including cassava, maize, yam, at least one-third3, and at least half ofand banana in Africa. Most of these these losses could easily be avertedgains, however, have come about as a using simple and affordable technologiesresult of an expansion of the planted and practices that prevent diseases andarea, but crop production per unit area pests from affecting plants and produce.of the land is lower than anywhere else Ensuring plant health, therefore, is onein the world. of IITA’s most important R4D strategies to improve agricultural productivity andYet the continent is expected to improve food security and reduce poverty.food production dramatically, doublingor tripling the existing capacity, to This issue highlights some of thefeed over 200 million undernourished technologies and strategies developedpeople1. Although new varieties have and promoted by IITA and its partnerscontributed to improve crop production, for plant health protection.productivity, and quality, their The value of plant health managementperformance has been constrained by cannot be underestimated givensuboptimal conditions, such as declining the precarious nature of agriculturalsoil fertility, drought, attacks by pests systems in Africa with the evolution,and diseases, and lack of good quality establishment, and quick spread ofplanting material. pests and diseases, such as fruit flies,The current approach—expanding the cassava brown streak and bananaarea under agriculture to increase food bacterial wilt.production—is unsustainable and results Although plant health protectionin significant ecological damage. This measures are relatively easy to adopt,realization worldwide is driving the considerable training, awarenesssearch for newer options to intensify creation, and financial supportagriculture within the existing area. are required to improve skills andWe believe that ensuring plant health infrastructure in national systems tois pivotal to increase productivity and foster the technology transfer to farmsthe strategy of sustainable agriculture where plant health matters. True national defense is a huge offensive force against biological threats to food systems. - Hartmann, Director General, IITA1 FAO. 2010. The State of Food Insecurity in the World 2010. FAO, Rome.2 www.bis.gsi.gov.uk/foresight3 Oerke EC. 2006. J. Ag. Sci. 144: 31–43.2
  5. 5. To ensure food security in Africa, plant health matters need to be given immediateattention. Photo by J. Oliver, IITA. 3
  6. 6. NEWS The varieties are Tgx1740- 2f, Tgx1987-10f, and Tgx1987-62f. Tgx1740- 2f was developed by iiTA High in nutritive value, soybean is fast gaining appeal in Africa, offering a cheap source of protein. TheNigeria gets in collaboration with the crop is also emerging as animproved Department of Agricultural Research Services (DARS) in important feed, food, and raw material for producingcassava Malawi. Varieties Tgx1987- high-quality protein products. 10f and Tgx1987-62f for smallholder farmers it isThe Nigerian government were developed by iiTA in an important cash crop andhas released four improved collaboration with Nigeria’s also improves soil fertilitycassava varieties that are a NCRi. because of its ability to fixproduct of about a decade- high amounts of atmosphericold conventional breeding The Malawi Agricultural Technology Clearing nitrogen.research. These include NR01/0004, CR 41-10, TMS Committee officially approved the release of Tgx1740-2f00/0203, and TMS 01/0040. in January 2011 while the Conference onTMS 00/0203 and TMS01/0040 were bred by iiTA Nigeria Varietal Release humid tropics Committee releasedscientists, while NR 01/0004 Tgx1987-10f and Tgx1987- The Consortium for improvingwas bred by the Umudike, 62f in December 2010. Agriculture-based livelihoodsNigeria-based National Root in Central Africa (CiAlCA)Crops Research institute, and The varieties outperformed the standard and local checks and the CgiAR ConsortiumCR 41-10 by the Colombia- Research Program (CRP) onbased international Center for grown in the two countries, with high grain yield in the Humid Tropics led by iiTATropical Agriculture (CiAT). will convene an international multiple locations under on-on-farm prerelease trials station and on-farm trials. conference on Challengesinvolving local farmers in eight and opportunities forstates of the country show Many farmers preferred Agricultural Intensification ofthat the improved varieties the varieties because they the Humid-Highland Systemsoutperformed local checks smother weeds and reduce of sub-Saharan Africa, inwith an average yield of about the cost of weeding. farmers kigali, Rwanda, on 24-2731 t/ha compared with 26 t/ that participated in the on- october 2011.ha recorded by the local farm trials of the varieties last year said they preferred them The humid highlands invarieties. sub-Saharan Africa are especially for their goldenfarmers love the varieties color at maturity. characterized by highfor their excellent culinary population densities andqualities, high yield, and in Malawi, Tgx1740-2f require intensification.resistance to pests and gave the highest mean Unfortunately, manydiseases. grain yield of 2.5 t/ha. it communities lack easy exceeded the yield of checks, access to the means toThe new varieties seek to grain variety Nasoko by achieve this.strengthen Nigeria’s lead in 10% and the widely growncassava production, increase promiscuous variety Magoye The conference aims to takefarmers’ incomes, and by 32% during the two-year stock of the state-of the art inguarantee food security. multilocation on-station trials. agricultural intensification in the highlands of sub-Sahraran The variety performed Africa, and to chart theBetter soybean equally well during on-farm participatory variety selectionTwo African nations—Malawi trials in four districts of centraland Nigeria—have released Malawi. in the 2009/10three improved soybean season, it outyielded allvarieties that can enhance the new types of soybeanthe productivity of the crop varieties under testing withand offer farmers better 2.2 t/ha. it also surpassedopportunities. Nasoko by 15% and Magoye by 38%.4
  7. 7. way forward for agriculturalresearch for development in Liberia andthe humid highlands, through Ghana to developkeynote presentations, oraland poster presentations, and agriculturestrategic panel discussions. The governments of ghanaUPoCA gives and the Republic of liberia have officially agreed tofarmers a lifeline jointly develop, promote, and implement research activitiesCassava value addition to improve their agriculturalis helping African farmers sectors.increase their income, andimprove livelihoods and A memorandum offood security through a understanding was signed byUSAiD-funded project called Happy cassava woman representatives of ghana andUnleashing the Power of farmer. Photo by IITA. liberia, with the assistanceCassava (UPoCA). of iiTA’s Sustainable Tree farmers benefited from Crops Program (STCP), inimplemented in seven improved cassava cuttings, collaboration with the ghanaAfrican countries—Nigeria, training, and capacity building Cocoa Board. iiTA/STCPDR Congo, ghana, Malawi, for processors. works in both countries.Mozambique, Tanzania, in Nigeria the project linkedand Sierra leone—by iiTA, The agreement was signed up processors to farmers for by the Minister of finance andthe project has benefited steady production/supplythousands of farmers in these Economic Planning, kwabena of cassava roots, provided Duffuor, and the Chiefcountries. improved cuttings and Executive of CoCoBoD,in Sierra leone, the training, and also helped build Anthony Fofie, for Ghana, andTongea Women farmers the capacities of farmers and by the Minister of Agriculture,in Sandeyalu community processors. florence Chenoweth, andformed the Tongea womens farmers in ido community, the Deputy Director generaldevelopment association oyo State, Nigeria, have of the Central Agriculturalcomprised of 54 women and more than doubled the yield Research institute (CARi),4 men. of cassava from an average Abugarshall kai on behalf ofThrough the iiTA-UPoCA of 10 t/ha to more than liberia.project, a cassava 20 t/ha. other states that Under the MoU, the Cocoamicroprocessing center was benefited from the UPoCA Research institute ofsubsequently inaugurated, project were osun, ondo, ghana and liberia’s CARiproviding farmers with Ekiti, kogi, Nasarawa, and will exchange expertise,a financial window of Benue states. knowledge, and geneticopportunity. incomes from farmers say the project has resources (seeds and nurseryUSAiD projects such as increased the production of development) to develop andUPoCA have helped the cassava with the availability improve the tree crops sectorpeople of Sandeyalu in of improved cassava stems, in Liberia. Specifically, therebuilding their community making food more secure and national research institutionsafter years of civil unrest. generating wealth. of both countries will facilitateThis success story echoes the provision of planting Apart from boosting the material as requested byacross other countries such productivity of cassava in theas Nigeria, DR Congo, either countries, make project areas and maximizing available research andghana, Malawi, Mozambique, the use of the root crop, theand Tanzania where UPoCA training facilities and materials project is also promoting food to visiting scientists fromis being implemented. security and improving the either institution, and providein Malawi, UPoCA helped incomes of women farmers technical expertise for therevive a moribund starch and processors in particular, successful implementation offactory—the first in that and African farmers in mutually-agreed projects.country. Thousands of general. 5
  8. 8. Climate change plant health &Irmgard Hoeschle-Zeledon*, i.zeledon@cgiar.org or sp-ipm@cgiar.orgThe discussion on the impact of climate technologies (e.g., predictive models,change (CC) on agriculture has often diagnostic tools) that are suitable forfocused on how changes in temperature, diverse agroecologies including therainfall, and CO2 concentrations will tropics, wet, humid, semiarid, and dry,affect the suitability of temperate and to some extent the temperateregions for crop production and how zones as well. The broad knowledgecrops will react in terms of yields. The and experience of centers provide aneffects of climate change on biotic unprecedented advantage to assess thefactors in the tropics, such as weeds, products and technologies in differentpests, and pathogens (hereafter agroecologies and weather settings andreferred to as pests), have not received to determine their resilience and abilitymuch attention. to cope in altered climatic situations.Empirical data exist, however, to show Several programs directly focus onthat these biotic factors have major managing pests. For instance, theeffects in determining productivity in breeding of crop varieties for resistancethe tropics. For instance, during the to pests and pathogens has always1997 El Niño phenomenon, the mean been a focus of the CGIAR. With thetemperature on the Peruvian coast uncertainties of CC, this work hasincreased by about 5 °C above the become more relevant. Breeding forannual average, causing a decrease resistance to drought and waterlogging,in potato infestation by the leafminer although not the primary objectives,fly Liriomyza hydobrensis, which also aim at making varieties betterotherwise was a major pest. However, able to tolerate biotic threats, sincethe abundance and infestation severity drought and excess water in the soilof all other pests increased in all crops, both increase the plants’ vulnerability toincluding potato (Kroschel et al. 2010). these factors.The complex consequences of CCparticularly on pests and pathogens A good example is the effort to developare still only imperfectly understood drought-resistant maize cultivars(Gregory et al. 2009). by CIMMYT and IITA. These will not only allow the expansion of maizeCGIAR’s work on climate change production into areas with less reliableWhat are IITA and the other centers of rainfalls but also ensure the continuedthe Consultative Group on International production in regions that are proneAgricultural Research (CGIAR) doing to future water scarcity. Drought-to mitigate the impacts and adapt to tolerant cultivars also reduce the riskthe effects of CC on pests? Historically, of aflatoxin contamination in the field.CGIAR centers have a broad R4D Additional characters are incorporatedfocus; centers have been developing into the drought-tolerant maize, such asknowledge (e.g., pest profiles), products resistance to maize streak disease which(e.g., new crop varieties, biocontrol is endemic in Africa. Similar programsagents against invasive pests), and are ongoing to develop drought-resilient*Coordinator of the CGIAR Systemwide Program on Integrated Pest Management (SP-IPM)convened by IITA.6
  9. 9. cassava and cowpea, and yam with the distribution of the species due totolerance for major pests. increasing temperatures. The approach can also be used for other insectThe CGIAR centers are also working species. Hence, CIP created the Insecttowards the development of cropping Life Cycle Modeling software (ILCYM)systems with greater intra- and to facilitate the development of otherinterspecific diversity to increase insect phenology models. With itsresilience to CC-induced threats from support, the phenology model can bebiotic factors. For example, IITA is implemented and allows for spatialpromoting maize–cowpea intercropping simulation of insect activities.to reduce the pest pressure on cowpea. Many centers support the collectionBioversity International is exploring and conservation of plant genetichow intra-specific crop genetic diversity diversity that can be built into newon-farm not only reduces current cultivars to enhance their resistancecrop losses to pests and pathogens, to biotic stresses. Diagnostics capacitybut also decreases the risk of genetic is continuously augmented for thevulnerability and the potential of accurate and timely recognition offuture crop damage, thus enhancing endemic pests, new variants, andthe impact of other IPM strategies invasive pests. Crop biodiversity—and providing farmers with increased landraces and wild relatives that are theadaptive capacity to buffer against reservoirs of genes for abiotic and bioticclimatic changes. factors—is conserved ex situ to protect the species from erosion by CC-inducedCIP developed a temperature-driven changes.phenology model for the potato tubermoth, Phthorimaea operculella that In a collaborative effort, CIP, IITA, icipe,provides good predictions for the and partners in Germany and Africa arepopulation in areas where the pest implementing a project to understandexists at present (Kroschel et al. 2010). the effects of rising temperatures on theLinked with geographic information distribution and severity of major insectsystems (GIS) and atmospheric pests on main food crops. ILCYM will betemperature, the model allows the further improved and adapted to cover asimulation of risk indices on a worldwide wide range of insect species. The resultsscale to predict future changes in will contribute to filling the knowledgeDiverse crop production system. Photo by IITA. 7
  10. 10. gap about CC effects on economically streak, soybean rust, and pod borerimportant insect herbivores and their pests, among others.natural enemies. As whiteflies and aphids are consideredIITA is planning to research the effect of to become more problematic withchanges in temperature on the invasion increased temperatures, IITA is alsopotential of major biotic threats in the preparing research on the biocontrol ofGreat Lakes region of East Africa and different whitefly and aphid species inelsewhere: Banana bunchy top virus vegetables and staple crops.(BBTV), Banana Xanthomonas Wilt(BXW), and Panama Disease–Tropical A project has been proposed onRace 4, cassava brown streak virus the bio-enhancement of seeds anddisease, cassava mosaic disease, maize seedlings of cereals and vegetables A BClimate change scenarios for the potato tuber moth, Phthorimaea operculella: (A)Generation index (generations/year) under present temperature conditions, and(B) Change in numbers of generations/year by 2050 using the atmospheric generalcirculation model (Govindasamy et al. 2003).8
  11. 11. for East Africa to stimulate the plants’ In collaboration with CABI, communitydefense mechanisms against pests surveillance for pests and diseases willand pathogens expected to increase in take place through the expansion of thenumber, frequency, and severity. This mobile plant clinic network.project also addresses the registrationof biopesticides and the availability Knowledge and decision supportof endophytes to the tissue culture tools for the management of potatoindustry. and sweetpotato pests (diseases and insects) will be developed andCGIAR research programs assessed in relation to the expectedUnder the new CGIAR Research intensification of the agroecosystems inPrograms (CRPs), centers are the humid and subhumid tropics.addressing CC-induced crop healthissues in various ways. Breeding Sustainable management of cassavafor resistance to predicted biotic virus disease in the cassava-basedstresses continues to be a major system will also be studied, and thefocus in CRP3 (roots, tubers, vulnerabilities of these systems to CC-banana) and its subcomponents. induced pest and disease problems willThis component, coordinated by be determined.CIP, specifically recognizes CC and The CIAT-coordinated CRP on CC,agricultural intensification as drivers Agriculture, and Food Security beganfor higher pressure from pests. Hence, operations this year. It will continuethis program aims at developing the activities initiated by the CGIARmanagement strategies for priority Challenge Program on CC. This CRPbiotic threats to these crops. These aims at mainstreaming strategiesinclude the development of improved that address the management of CC-detection and monitoring tools, and induced pest and disease threats amongsurveillance methods for detecting international and national agencies. Itand mapping existing, emerging, will identify and test innovations thatand resurgent molecular pests and enable communities to better managepathogens. It will look into increasing and adapt to climate-related risks fromgeneral plant and root health through biotic factors.the enhancement of the natural diseasesuppressing potential of soils, and the Recommendationsantagonistic pest and disease potential A lot of surprise shifts in ecosystemsof the aboveground agroecosystems. could come. It is therefore important that research capacity and knowledgeThe CRP on Integrated Systems for the bases are maintained to understand andHumid Tropics, led by IITA, will have rapidly react to mitigate any debilitatinga substantial focus on CC, its impact impacts (Shaw and Osborne 2011).on pests, and plans for mitigation.For example, research will establish To accomplish this, it is necessarythe relationship between CC and key to establish good baseline data oncassava pests to develop integrated pest current pest status in agroecosystems.management (IPM) strategies including This knowledge base will serve asthose for whitefly, African root and tuber a reference point to measure thescale, termite, green mite, aphid, and fluctuations and the effectiveness ofmealybug. interventions.Phenology models for insect and mite It is important to determine the keypests and their antagonists on several weather variables that could change ascrops will be developed and validated a consequence of CC and their influenceand their potential for changes in on agroecosystems and pests, andwarming will be determined. establish preemptive coping strategies. 9
  12. 12. delivery systems for pest control products (Strand 2000 in Juroszek and Tiedemann 2011). Preventive crop protection measures may become more relevant under CC to reduce the risks (Juroszek and Tiedemann 2011). CC is a global problem that affects all countries. Hence, global cooperation is required. However, given the nature of plant pests and pathogens, more localLarva of the noctuid moth feeding on the or regional strategies need to be putpistil of cowpea. Photo by S. Muranaka, IITA. in place that define potential risks and measures to tackle expected threats.Available CC models could be handy for Investments in early detection systems,predicting CC factors. including border controls to monitor the migration of pests through plants,A diverse scientific base including plant products, and other goods, will bespecialists in pathology, entomology, the key to avoid the spread of invasiveecology, taxonomy, and epidemiology pests and reduce high management andis required. They should work together eradication costs (FAO).to ensure that the outcomes oftheir research are linked to existing New farming practices, differentknowledge, economic forces, and crops, and IPM technologies must becommon understanding (Shaw and developed to control the establishedOsborne 2011). pests and prevent the spread of new ones (FAO).As it generally takes more than 10 yearsto breed a new resistant cultivar of a Governments should considercrop, breeding programs must start well developing country-specific strategiesin advance of the serious risk of a biotic to cope with CC-induced changes andthreat Breeders need to be informed put in place favorable policies for theon the problems which might become introduction and promotion of newimportant in the future (Chakraborty technologies for CHM.et al. 1998 in Juroszek and Tiedemann It is also crucial to create and augment2011). awareness about the effects of CCCrops being bred for abiotic threats such among policymakers and other officialsas drought, waterlogging, and salinity involved in developing agriculturalshould be prepared for the pests that strategies.could flourish under these conditions Referencesand select varieties that can tolerate Chakraborty S and Newton AC. 2011. Plantpests as well. Pathology 60: 2-14. FAO. unknown. ftp://ftp.fao.org/docrep/fao/010/Changes in occurrence, prevalence, and i0142e/i0142e06.pdfseverity of infections and infestations Govindasamy B et al. 2003. Climate Dynamicswill also affect crop health management 21: 391-404.(CHM) practices. There is a need to Gregory PJ et al. 2009. Journal of Experimentaleffectively disseminate and use those Botany 60: 2827-2838.techniques that are currently underused Juroszek P and von Tiedemann A. 2011. Plant(Juroszek and Tiedemann 2011). Pathology 60: 100-112. Kroschel J et al. 2010. http://www.spipm.cgiar.Significant contributions could be org/ipm-research-briefsmade in improved field monitoring Shaw MW and Osborne TM. 2011. Plantof pests and diseases, and better Pathology 60: 31-43.10
  13. 13. Climate change is everyone’s responsibilityClimate change (CC) is a variations in climate (e.g., Using simulation models,long-term change in the permanent increase in attempts the worldstatistical distribution of average temperature) that over are being made toglobal weather patterns might irreversibly affect determine the impact ofover periods of time that biodiversity in a given CC on agroecosystems torange from decades to region. establish appropriate copingmillions of years. Several strategies, particularly In the context offactors, known as climate for the negative impacts. agriculture, sudden andforcers, usually natural Although this appears abnormal changes inevents such as volcanic simple, it is the most weather could changeeruptions, earthquakes, complex issue confronting the suitability of a givensolar radiation, and ocean researchers, policymakers, environment for cultivationcurrents shape climate governments, and of crops. This could be duechange. entrepreneurs worldwide. to abiotic factors such asHowever, the climate forcer drought, heat (cold), or Communities are workingof the 21st century CC— excessive water directly together to bridge thecarbon dioxide (CO2)—is linked to weather or gaps and establish globalmainly human-induced and simply due to increased coordination networks toattributed to the burning pests and diseases that mitigate the impact ofof fossil fuels and tropical would severely impede CC. IITA and other CGIARdeforestation. The property performance of the crops. centers, together withof CO2 to trap heat within Since crops, diseases national and internationalthe earth’s atmosphere (pathogens), and pests organizations, areis contributing to global (including vectors) are contributing to thesewarming. Thus, a rise in intimately associated endeavors with a primaryCO2 levels increases the and influenced by the focus on conservingwarming effect. Trapped environment, any shift in biodiversity and improvingheat in the atmosphere these factors will alter the the resilience ofwarms oceans, melts ice balance, and could have smallholder agriculture incaps, raises sea levels, a positive impact (e.g., the developing countriesand increases average decreased pest pressure) in Africa, Asia, and Latinsurface temperature, all of or negative impact (e.g., America.which are affecting normal increased pest pressure) onweather patterns. overall crop performance.Some of the abnormalchanges experiencedover the last two decadesinclude severe andprolonged droughts,extreme storms andprolonged rainfall pattern,high temperatures, andheat waves. These suddenand extreme variationsin weather patterns dueto ‘global warming’ haveprofound effects on livingorganisms on earth.The altered conditionscreate risks as well asopportunities favoring Life on earth is a dynamic process and intimatelycertain living beings over connected to the biotic forms in cohabitation, farmingothers and contribute to systems, and environment. A shift in one parametershifts in niches. In addition, alters the delicate balance in an interconnected world.it could lead to long-term Source: L. Kumar, IITA. 11
  14. 14. fEATURESTowards a healthy bananaTC industry in East AfricaThomas Dubois, t.dubois@cgiar.orgTissue culture banana modified banana. In other words, the TCBanana in smallholder farmer systems technology can help banana farmers tois traditionally propagated by means make the transition from subsistence toof suckers. These contain soil-borne income generation.pests and diseases, and by using them, However, TC plantlets are relativelyfarmers unknowingly distribute and fragile and require appropriateperpetuate pest and disease problems. management practices to fully harness their potential, especially during thePlants produced by tissue culture (TC), initial growth stages shortly after beingbecause they are produced axenically transplanted to the field. In East Africa,in the laboratory, are material that is TC plantlets are often planted in fieldsfree from pests and diseases with the burdened with biotic pest pressures andexception of fastidious bacteria and abiotic constraints.viruses. A SWOT analysisThere are many added benefits to The importance of the private sectorusing TC plants: (1) they are more The adoption of TC technology is stillvigorous, allowing for faster and relatively low in East Africa. In Kenya,superior yields; (2) more uniform, coverage of TC banana is estimatedallowing for better marketing; and (3) at 5–7% of the total banana acreage;can be produced in huge quantities in adoption rates are significantly lower inshort periods of time, allowing for faster countries such as Uganda, Burundi, andand better distribution of existing and Tanzania, although reliable data do notnew cultivars, including genetically exist.Young tissue culture plantation in Nairobi, Kenya. Photo by T. Dubois, IITA.12
  15. 15. (t/ha/cycle) 60 50 tissue culture suckers 40 30 20 10 0 low input high inputCumulative yield (t/ha/cycle) of a plantation derived from tissue culture (orange bars)compared to one derived from conventional planting material (blue bars), over 5cropping cycles and under two management regimes (low input and high input). Everylittle block represents one crop cycle. Data based on 1,600 plants total.In East Africa, the technology is during the production process, (2) plantbooming under the impetus from the health certification, and (3) regulatoryprivate sector. At least 10 commercial procedures. Such conditions areprivate laboratories have sprung up especially important to avoid spread ofin the last decade in Burundi, Kenya, viruses, which are easily transmittedUganda, and Tanzania. Collectively, through TC plantlets.they produce at least 2 million plants/year, although exact numbers seem to For instance, Banana bunchy top virusfluctuate widely and are hard to come (BBTV) is on the list of the 100 mostby. Most of these companies manage dangerous invasive species worldwide.the entire production chain, from It is widely distributed in Central Africasourcing the mother plants to weaning and also in Burundi and Rwanda inthe TC plantlets. Despite the steep entry East Africa, yet implementation of virusbarrier, the TC business is very lucrative indexing schemes is largely absent infor the entrepreneur who engages in East Africa. It is important to put inplantlet production. In some countries, place standard procedures for ensuringuniversities and research organizations the production and distribution of high-are also involved in the commercial quality, virus-free planting material,production of TC banana. and to establish independent agencies that set and implement standards andLack of quality standards and virus improve the skills of personnel. In Eastindexing Africa, certification schemes need to beOne of the biggest dangers for regionally harmonized, especially withsustainable commercial production of TC the transnational movement of plantsplants is the lack of several essentials: between the countries, so that there is(1) standards for quality management no weak link in the region. 13
  16. 16. Unregulation—a potential danger to the Another important requirement forspread of diseases TC producers is sustainable access toAt present, the commercial production virus-free and true-to-type motherof TC banana plantlets is largely plants and this is currently lacking.unregulated. Not only are TC banana The establishment of certified motherplantlets being moved in very large plant gardens as a common resource,quantities across borders; uncertified either by governmental agenciesmother material is also crossing or a consortium of commercial TCborders. This practice is potentially producers, would provide this essentialrisky, and could perpetuate infected requirement.sources and cause new outbreaks ofdisease. Contrary to a general perception, especially among donors, it is notIn the ideal situation, there need merely the standards themselvesto be certification standards for the that are a constraint, but also a lackquality and health of TC plants and the of knowledge on how procedures aremonitoring of TC producer operations. actually implemented along the valueThese are largely ignored because chain, through certification schemes.of poor awareness, and the lack of The equipment for virus indexing hascapacity and regulations required for become relatively cheap and technicalthe implementation of such standards. skills are quite easily acquired. TheirTo transform the system, governments costs can be offset, e.g., through aand/or the TC industry could consider service-based fee to private sectorcommon facilities to implement stakeholders.certification schemes. For instance, anaccredited governmental or independent Also, emphasis could equally be placedvirus indexing laboratory, established as on certifying general operationala commercial service for TC operators, procedures in a private TC laboratory.would leverage costs and improve TC Currently, the quality of TC plantletsstandards. varies significantly, and several producers are struggling with off-types and accidental mixtures of varieties that become apparent only after being planted in the field, resulting in negative perceptions about TC. Certification schemes need to be implemented in such a way that they do not become burdensome to producers or create bureaucratic barriers. Several quality certification schemes used for clonal crops, including banana, from other regions can be considered to develop an appropriate scheme for East Africa. Ultimately, it is not only the commercial sector that should self- regulate; governmental bodies need to take responsibility. Nurseries Nurseries for TC plants are essential, as they act as a distribution hub connecting producers to the farmers. They also Plantain for sale in market. Photo by IITA. act as focus centers for farmers and14
  17. 17. farmers’ groups, and are therefore aneasily approachable venue for training Test tubes to farms: how it’s doneand other interventions. The surveyby IITA and University of Hohenheim Tissue culture plantlets are madeof all TC nurseries in Burundi, Kenya, in specialized laboratories, and theand Uganda, found that nurseries in technology consists of a few basicEast Africa face an array of problems. steps: (1) the apical meristem isRelationships between producers and isolated from the mother plant andnurseries, especially those related to induced to form shoots, (2) the shootstiming, quality, and quantity of plantlet are multiplied, (3) when plants aresupply, are often suboptimal. needed, the multiplied shoots are put on a root-inducing medium, (4)At the nursery level, there are three the young plants are transferred to amain operational issues: access to screenhouse for hardening, and (5) thewater, credit, and the transport of plants are planted in farmers’ fields.plantlets. The location of the nurseriesis also crucial. Nurseries need to beclose to the producer and to the market,otherwise they might fail. Clear drivers is subsidized. Virtually all TC plantletsfor the success of a nursery are good are being bought by developmentalagricultural practices and, interestingly, agencies, which then pass on thesea diversification into crops outside plantlets to often untrained farmers,banana. free of charge, and without embedding this transfer in an encompassingIn TC banana value chains, nurseries training program or input package (e.g.,have different roles across countries in fertilizers).East Africa. In Uganda, nurseries arerun as businesses independent of the Empowerment of farmers in the valueTC operators and of the farmers. In chain through farmers’ groupsBurundi, the nurseries are owned and Organizing banana farmers into groupsmanaged by the producers. In Kenya, has long been considered advantageous,nurseries are run as entities separate because of increased buying and sellingfrom the producers, and most of them power, reduced economic and socialare owned by farmers’ groups that act risk, increased economies of scale, andas the customers for these nurseries. improved access to credit and inputs byThe business model in Kenya seems to formally certified groups.hold the secret for a sustainable andvigorous link between producers and The study by IITA and the Universityfarmers. of Hohenheim of the farmer-to-market linkage in Uganda demonstrated thatDistorted value chains farmers in marketing groups obtainOne danger for a healthy commercial higher prices than their ungroupedTC sector is the lack of sustainable colleagues. The certification of farmers’market pathways to deliver the plants groups implemented by IITA’s nationalto the farmers. Especially in Burundi partners, ISABU (LInstitut des Sciencesand Uganda, outlet markets for TC Agronomiques du Burundi) in Burundiplantlets are mainly governmental and VEDCO (Volunteer Efforts andand nongovernmental organizations, a Development Concerns) in Uganda,situation which seems unsustainable inthe long term. has made them eligible for savings and credit schemes. Some have evenThe sustainability of the banana TC engaged in other commercial activities,industry is especially worrisome in such as the start-up of a cateringBurundi, where the entire value chain service. 15
  18. 18. Training of farmers group in business skills in Uganda. Photo by Moses Lule.The importance of a training package training program was monitored. So far,In East Africa, the distribution of a total of 851 separate training eventssuperior planting material alone will have been implemented in Burundi,not ensure a good crop. Commercial Kenya, and Uganda, and through thefarmers are skilled in juggling the partnership, 10 new farmers’ groupsinputs and effort needed to produce and 5 new nurseries have beencrops and make a profit but smallholder established.farmers are constrained by factors suchas a lack of land and capital, access Location, location, locationto technology, and a good marketing TC banana plantlets come at a cost, andinfrastructure. Therefore, efficient might not be economically beneficialdistribution systems will be needed throughout all banana-producing areasto deliver the TC plants as part of a in East Africa. Location is everything.package, including training and accessto microcredit. IITA, in collaboration with Makerere University, conducted a cost-benefitIITA and its national partners, ISABU, analysis of the technology basedJKUAT (Jomo Kenyatta University on a comprehensive quantitativeof Agriculture and Technology), and questionnaire with 240 farmers acrossVEDCO, have been implementing hands- four districts in Uganda, and comparedon, comprehensive training schemes it with the use of conventional plantingfor farmers as well as the operators of material.TC banana nurseries. Training schemesencompass modules in agronomy, Both production costs and revenuesmarketing, business and financing, and were consistently higher for TC-derivedfor farmers, group formation and group material than for suckers. However,dynamics. Participants were followed banana prices varied greatly withfor over a year, and their ability to district and declined significantly withimplement the skills learned during the increasing distance from the main16
  19. 19. market (see graph). Also, production Sound socioeconomic analyses arecosts decreased significantly the further crucial to guide policy strategies, learnaway the farms were from Kampala due from successes already achieved, andto better agroecological conditions and identify important constraints for athe much reduced pressure from pests wider dissemination of TC banana in theand diseases. As a result, although both region.TC plantlets and suckers were profitableto the farmer, TC material was more Earlier studies on the impacts of TCprofitable than suckers closer to the banana in the region have eithermain banana market. employed ex ante methods before any meaningful adoption was actuallyIn districts with low banana prices and observable, or they have usedat a greater distance from the main relatively simple and ad hoc qualitativebanana market, farmers could receive methodological tools, which do not allowsimilar gains by planting suckers rather robust and representative statements.than TC plants. For a farmer in Uganda, The large body of subjective ‘gray’it makes economical sense to grow TC literature, sometimes unconditionallybanana close to the main urban market. and unilaterally promoting the benefitsAn objective ex-post assessment of TC banana, without consideringDespite a booming commercial sector, the quality of the plant material,there is only anecdotal evidence that input package, and market access,farmers who have adopted TC banana risks having an adverse effect on thebenefit tremendously in terms of adoption of the technology in thehigher yields and household incomes. long term.gross margins (Ugsh/ha/year)7,000,000 tissue culture suckers6,000,0005,000,0004,000,0003,000,0002,000,0001,000,000 0 Luwero Mukono Masaka Rukungiri 10 km further away from the market 350 kmGross margins (in Ugandan shillings)/ha/year of banana plantations derived from tissueculture (yellow bars) compared to conventional planting material (orange bars) inUganda, the further away from the main banana market (Kampala). 17
  20. 20. The University of Göttingen, in and requirements. This study findscollaboration with IITA, is currently that farmers’ education, access toanswering the following main agricultural information, knowledge ofresearch questions: (1) What are the the location of a TC nursery within adeterminants of TC banana adoption reasonable distance, and affiliation toamong farmers? (2) What are the social groups significantly increase theimpacts of this technology on on-farm likelihood of the TC technology beingproductivity, household income and adopted.income distribution, and poverty andfood security? (3) How do institutional This study also highlights the positivefactors in technology delivery and role of access to credit and of genderproduct marketing influence adoption in the adoption of TC material. Farmersand impact? with access to credit and female-headed households are more likely to adopt TCSome of these research questions have plants. The latter finding is particularlybeen answered. In Kenya, a substantial interesting from a policy perspective,share of the population has heard about because it shows that, when there is anTC banana and is, therefore, generally equal chance for both men and womenaware of the technology’s existence, to acquire sufficient knowledge aboutalthough only a few have had a chance an innovation, women are more likely toto fully understand its performance adopt it.Banana market in Ikire, Nigeria. Photo by O. Adebayo, IITA.18
  21. 21. GHU: Gateway for the safeexchange of germplasmLava Kumar, l.kumar@cgiar.orgInternational exchange of germplasm:an essential step for sharinginternational public goodsSince its inception in 1967, IITA hasbeen actively involved in the collection,conservation, and use of the plantgenetic resources of important crops,such as banana and plantain, cassava,cowpea, maize, soybean, and yam,and their wild relatives from Africa andother parts of the world. Using thisgermplasm, IITA’s crop improvementprograms, based in several locationsin sub-Saharan Africa, have been Seed testing. Photo by IITA.developing high-yielding, nutritionally Germplasm exchange: benefits and risks Crop germplasm—seeds, has an inherent risk of in 1993. The accidental plants, or plant parts introducing exotic plant introduction of the Banana suitable for propagation— pathogens (viruses, fungi, bunchy top virus in Malawi is a high-value commodity bacteria, phytoplasma, has affected banana very frequently exchanged and other pathogenic production in over 3000 for agricultural research, microbes), weeds, insects, ha and completely wiped crop diversification, and nematodes (pests). out production in Nkhota food production, and Due to a lack of competition Khota and Nkhatabay. In commerce. International and resistance, introduced addition, pests associated exchanges of useful pests often result in with the germplasm germplasm have been devastating epidemics in may reduce its longevity the major factor in territories in which they did during storage and may the diversification and not exist before, leading have negative effects improvement of global to severe economic losses. on crop performance agriculture. For instance, The cassava green mite, (e.g., nematodes in about 30% of the world’s Mononychellus tanajoa, a yam tubers). Therefore, food production is derived native of Latin America, several safeguards from crops originating was accidentally introduced have been established in other countries. into Africa in the 1970s to prevent the spread Cassava, first introduced and spread to almost all of pests through the from Latin America by the cassava-producing movement of germplasm the Portuguese in 1558, regions, reducing yields from one area to another. has been established as by 30−50%. This pest These quarantine or one of the major food was controlled through the phytosanitary measures staples in sub-Saharan introduction of a natural are enforced through Africa. Germplasm enemy from Latin America, national and international exchange, however, Typhlodromalus aripo, legislation. 19
  22. 22. Scheme for phytosanitary management of germplasm. Source: L. Kumar, IITA.superior crop varieties resistant to against the introduction of exotic pestspests, diseases, and drought. into countries where they do not occur; (e) ensures phytosanitary managementThese are regularly exchanged with of plant genetic resources conservednational and international programs in the IITA genebank; and (f) providesfor crop improvement and agriculture capacity building and awarenessdevelopment. creation on phytosanitary measures.Germplasm safety matters GHU operates within the framework ofAs part of the measures to prevent the the procedures for the introduction andinadvertent spread of pests through export of germplasm established byexchange activities, IITA has established the government of the host country ina Germplasm Health Unit (GHU). The which IITA’s operations are based. ForGHU is responsible for the production, instance, all the exchange operations ofmaintenance, and exchange of healthy IITA’s activities in Nigeria are organized(pest-free) germplasm in accordance in accordance with the legislation of thewith the international requirements on Nigerian Agriculture Quarantine Serviceplant protection. These are covered (NAQS) of the Federal Department ofby the International Plant Protection Agriculture, Nigeria.Convention (IPPC) under the auspicesof FAO, and those set up by the Ensuring exchange of clean germplasmInter-African Phytosanitary Council Crops researched at IITA comprise those(IAPSC) and National Plant Protection propagated through botanical seeds orOrganizations (NPPOs) to safeguard true seeds (maize, soybean, cowpea,agriculture and natural resources from and other legumes of importancethe risks associated with the entry, to African farming) and crops thatestablishment, or spread of plant pests. are propagated through vegetative propagules, including stems (e.g.,GHU (a) facilitates germplasm exchange cassava), tubers (e.g., yam), and inin support of IITA’s international crop vitro plants (e.g., banana and plantain,improvement programs; (b) inspects cassava, and yam).for pests and certifies the health statusof germplasm; (c) ensures compliance Each type of germplasm demands awith the national regulations on plant unique set of procedures for assessingintroductions and exports; (d) guards the health status of the material. At20
  23. 23. IITA, this work goes on from production for the presence of pests. Detectionto postharvest to the point when the methods used for this purpose includematerial is dispatched. visual inspection of dry seeds, seed washing, agar and blotter tests, seedPlant material generated for soaking, and seedling symptom testsinternational exchange is inspected which aid in identifying any pest-with the technical officers of NPPO infested material. Additional techniquesduring the active growth stage in the are used for pest identification includingfield or screenhouse to ensure the culturing techniques, microscopy, andselection of pest-free material. Thesorted materials (seeds or vegetative biochemical analyses of samples bypropagules) are then brought to the enzyme-linked immunosorbent assayGHU laboratories for critical inspection (ELISA), polymerase chain reaction Seeds as vehicles of pests True seeds (botanical seeds) offer through planting material. Therefore, the safest form in which to exchange exchanging planting material in the germplasm. Despite their ability to serve form of stem cuttings (e.g., cassava and as potential vehicles for the spread of sweetpotato), tubers (e.g., yam and pests, it is relatively easy to sort out Irish potato), or suckers (e.g., banana contaminated seeds from healthy seeds. and plantain) poses the maximum risk Furthermore, seeds can be treated with of spreading pests. As a general rule, chemicals (e.g., Mancozeb at 2 g kg–1) quarantine regulations prohibit the to eliminate several types of fungi and exchange of vegetative propagules unless bacteria. Only a small fraction (about stocks are derived from plants certified as 10%) of the >1000 plant-infecting pest-free. Micropropagation or the in vitro virus species is capable of being spread propagation of plants using modern tissue through seeds (e.g.. Cowpea aphid- culture methods offers the safest option borne mosaic virus in cowpea is seed for exchanging vegetatively propagated transmitted, but not Cowpea golden crops. Procedures employed during in mosaic virus). Virus infesting seeds can vitro propagation result in the elimination be eliminated by grow-out tests, and of all pests, but not viruses and some seeds harvested from uninfected plants fastidious microbes. Special procedures offer the safest approach. are used to eliminate viruses from in vitro plants. Therefore, where possible, IITA In contrast, almost all the pests present exchanges only in vitro planting material in the vegetative tissues (stems, tubers, (tissue culture) produced under aseptic roots, suckers, in vitro plants) are spread conditions. Seeds pose less risk than clonally propagated materials Less risk High risk -Scope for phytosanitation -Phytosanitation is difficult and demands -Only few viruses can be special process transmitted through seed - All types of pathogens spread 21
  24. 24. (PCR), and genomic sequencing. Onlymaterials that are free of the regulated Categorization of pestsand unregulated quarantine pests are Pests are classified into (a) regulatedreleased for international exchange. pests and (b) unregulated pests.GHU also monitors for genetically Regulated pests are further classified into quarantine pests and regulatedmodified organisms (GMO) to comply nonquarantine pests.with the Cartagena biosafety protocol,also under the regulation of NPPOs. This Pests whose introduction into anis done mainly by seeking an additional area can result in severe destructiondeclaration from the exporting parties are classified as quarantine pests.on the GMO status of the planting Territories can be free of quarantinematerial as stipulated in the conditions pests (e.g., Fusarium oxysporum f. cubense Race 4 present in some partsof the import permit issued by the of Asia but not in Africa) or presentNPPO. Diagnostic capacity exists to but not widely distributed (Cassavamonitor germplasm for traces of GMOs brown streak viruses, Xanthomonasby PCR assays, targeting constitutive campestris pv. musacearum responsibleelements of transgene constructs, for banana bacterial wilt, and Bananasuch as promoters of Agrobacterium bunchy top virus occur in Africa, buttumefaciens or Cauliflower mosaic virus are restricted to certain regions).35S gene, that are widely used for Quarantine pests are rigorouslygenerating transgenic plants. controlled through official monitoring measures. Regulated nonquarantineComplying with regulations pests are widely distributed and theirGermplasm exchange activity presence in germplasm causes a losscommences with the application of of planting material or initiates a new disease cycle (e.g., Cucumber mosaica permit from a host country for virus infects a range of hosts, includinggermplasm import (for use in IITA’s banana, and is widely distributed).R4D programs) or germplasm export Regulated quarantine pests are(to partners, collaborators and other monitored by specific procedures.stakeholders, including IITA’s missions In general, all programs for thein other countries). This is an essential production of clean planting materials,process under the Convention of including those meant for internationalBiological Diversity (CBD) treaty that exchanges, ensure freedom from quarantine pests and regulatedregards biodiversity as a national nonquarantine pests.treasure, and requires authorizationfrom the respective governments The categorization of pests is usually country-specific. For instance, NAQSfor free exchanges. Every country classifies pests under three categories:has a nodal agency tasked withissuing permits for the movement of Category A: Pathogens which are not present in Nigeria and/or in anygermplasm. country in West AfricaIn addition, GHU applies for Category B: Pathogens which are ofphytosanitary certificates (PC) for the restricted local distribution in Nigeriaexport of material. The PC is issued and/or West Africa against which field inspection and or/seed healthby NPPO after the condition has been testing methods can provide adequatesatisfied that the material being protectionexported meets the phytosanitary Category C: Internationally widespreadstandards of the IPPC and the importing pathogens which affect seed quality.country. GHU invariably complies withnational regulations in obtaining these Pest lists and pest categorization are often updated.two documents for all seeds or plantmaterials sent or received. Similarly,22
  25. 25. Dangerous pathogens on the move The following pathogens provide the greatest threat to food security in sub-Saharan Africa. Cassava brown streak viruses -Emerging virus disease of cassava -Destroy tuberous roots -Occurs in Kenya, Uganda, Tanzania, Malawi, and Mozambique -Suspected in DRC, Congo, Burundi, Rwanda, Gabon, and Madagascar Banana bunchy top disease -BBTV-infected plants become unproductive -Major constraint to fruit production and the production and distribution of quality planting material -Widespread in Central Africa Banana bacterial wilt (BXW) -BXW affects fruit production and quality, and kills the plant -Widespread in East Africa Present Present Present Suspected No No No information information information Cassava brown streak Banana bunchy top Banana bacterial wiltwhen material is imported it is subjected has exchanged germplasm are Bénin,to post-entry inspection to ensure its Ghana, Cameroon, Kenya, and Southcompliance with the conditions specified Africa. Each of these countries hasin the import permit. Depending on the specific legislation. However, proceduresneed, material is held in the post-entry for health monitoring have the sameisolation facility until the necessary underlying principle, i.e., the exclusionclearances are obtained. Material that of pests and the prevention of pestssatisfies all the conditions is released for from spreading.IITA’s use. Phytosanitary protection of geneticFrom 2005 to 2010, GHU, from IITA‘s resourcesIbadan Station in Nigeria in liaison GHU ensures the phytosanitarywith NAQS, has facilitated about 492 management of the germplasm ofexchanges, 157 imports, and 335 food crops (about 27,000 accessions)exports of crop and other plant material conserved in the IITA genebankto 69 countries, 34 of which are in and also in the in situ germplasmAfrica (Fig. 1). USA, India, Colombia, collections of breeding programs.Mexico, and Japan are among the top Germplasm conserved in the genebank5 non-African countries. Within Africa, is systematically evaluated for itsthe top 5 countries with which IITA health status and clean germplasm 23
  26. 26. Fig. 1. Germplasm export and import events facilitated by GHU to various countriesaround the world. Source: L. Kumar, IITA. is conserved for distribution by IITA’s Genetic Resources Center (GRC). Contributing to phytosanitary capacity development in SSA Together with the Virology and Molecular Diagnostic Unit and GRC at IITA, Ibadan, GHU augments diagnostic procedures for monitoring pests in germplasm; develops a reference pest collection and DNA bank to use as controls; establishes DNA barcode databases of the pests of African food crops; and augments procedures for salvaging clean germplasm. GHU plays an active role in developing the skills of NPPOs in the testing for germplasm health and the production of pest-free germplasm via training courses and short-term assignments. It also creates awareness on quarantine pests, quality standards for planting material, and the sanitary and phytosanitary (SPS) measures. Knowledge and technologies developed are disseminated through training programs, the publication of protocol manuals, information flyers and a website (http://www.iita.org/ germplasm-health). The unit also collaborates with NPPOs and IAPSCInformation dissemination through exhibits as a technical partner to developand hands-on demos, IITA Open Day.Photo by L. Kumar, IITA. phytosanitary capacity in Africa.24
  27. 27. Dangers of unknownsCertain basic knowledge on to occur in coastal zones of southernpests is necessary to implement Africa for nearly a century. Like FSD,phytosanitary measures. Examples aboveground symptoms of CBSD areare the characteristics of the pest cryptic and difficult to recognize. Dueand its variants, its effect on the to insufficient knowledge on CBSDhost (symptoms), geographic and poor awareness, it is conceivabledistribution, alternative hosts, that cassava was moved, albeitmodes of spread, vectors, and inadvertently, from CBSD-affectedthe availability of diagnostic tools. areas to other cassava-producingInsufficient information compromises regions in Africa contributing to thethe phytosanitary inspection and virus spread in the continent.demands very stringent measures onthe production of planting material. These two examples depict the limitations of phytosanitary monitoringFor instance, frog skin disease and the potential risk for pest escape(FSD), a virus-like disease of cassava if adequate precautions are not taken.prevalent in certain parts of Latin To circumvent the limitations inAmerica, is difficult to diagnose diagnosis of uncharacterized, not-so-due to insufficient knowledge on well-characterized, and cryptic pests,its etiology and the lack of reliable monitoring programs are increasinglydiagnostic tools. Moreover, FSD relying on broad-spectrum diagnosticdoes not induce characteristic tools, including deep sequencing,symptoms in the aboveground parts which identify a range of relatedof the plant further complicating species in the same genus, family, orthe detection of infected sources. order.To avoid the risk of spreading FSD,in vitro plantlets generated from Although thesecassava plants produced in FSD-free approaches reducefields are moved. However, only a the risk of potentialfew organizations are capable of pest escape, they areproducing plants in this manner. expensive, laborious,To obtain useful germplasm from and detect everyany agencies that are incapable of species includingproducing planting material under benign endosymbiontsstringent phytosanitary conditions, and pose challengesthe material from the source requires to decisions onthat it be sent to a third party germplasm exchange.capable of producing FSD-free plants. Another approachThis procedure severely delays the depends on theexchange of material. production of “clean” planting materialSimilarly, the etiology of cassava using sources frombrown streak disease (CBSD) was pest-free areas.unraveled in the late 1990s and GHU adopts bothsucceeded by the development of these approaches todiagnostic tests for cassava brown increase confidence instreak viruses (CBSVs) that cause this germplasm health anddisease. But CBSD had been known safety. 25
  28. 28. Conservation of germfree-germplasmDominique Dumet, d.dumet@cgiar.org and Lava Kumar,l.kumar@cgiar.orgPlant genetic resources (germplasm) In the mid-1970s, IITA has initiatedare the foundation for sustainable an ex situ conservation of germplasmagriculture and global food security. of important African food cropsThey possess genes that offer resistance which are held in trust on behalf ofto pests and diseases and resilience humanity under the auspices of theto abiotic stresses, such as drought United Nations. To date, IITA’s Genetictolerance, soil erosion, and other Resources Center (GRC) conservesconstraints. over 27,000 accessions of six main collections of African staple crops,However, genetic resources are eroding namely, cowpea and other Vigna,at unprecedented rates as a result of soybean, maize, cassava, banana,the loss of habitat, outbreaks of pests and yam. Germplasm is distributedand diseases, and abiotic stresses. worldwide for use in research for foodTherefore, it has become imperative and agriculture. Depending on theto conserve genetic resources for species’ reproductive biology and modeagricultural sustainability and the of dissemination, collections are storedpreservation of global biodiversity. in field, seed, or in vitro genebanks. However, germplasm (seeds or vegetative propagules) infested with pathogens such as, viruses, fungi, bacteria, and nematodes, insects, mites and even weeds (hereafter all referred to as pests) can spread along with the planting materials. Because of this risk, planting materials are traditionally sourced from healthy-looking plants and as an additional safety measure they are treated with chemicals to eliminate bacteria, fungi, nematodes, insects and other pests. However, viral pathogens are difficult to detect and pose challenges to “clean” (pest-free) planting material production procedures. IITAs collections were sourced over 35 years from several countries in Africa and other parts of the world. Knowledge on viruses infecting crops conserved in the IITA genebank and the means for their detection andSeeds of important grain legumes are production of clean planting materialconserved in IITAs Genetic Resources have dramatically improved over theCenter. Photo by IITA. past two decades. To ensure that26
  29. 29. planting material involves in vitro procedures using meristem culture. In cassava, source plants are subjected to thermotherapy (exposing plants to 27-30 °C) from 1 to 3 weeks prior to meristem excision and in vitro propagation. In vitro plants are indexed for viruses and plants that test positive are discarded while virus-negative plants are further propagated for conservation in the in vitro genebank. So far, over 2000 accessions of clonal crops have been subjected to this process to derive virus-free plants. Production and conservation of "clean" planting material is expensive; however it improves the turn-around time for processing germplasm for exchange and dramatically improves its use. In addition, clean germplasm improves the viability of the material conserved in the genebank and prevents the risk ofConservation of virus-free germplasm. the accidental spread of pests from one region to another through the plantinggermplasm conserved is free of pests, materials.particularly viruses, a systematicapproach was taken to assess thehealth status of every accession in thegenebank and produce clean plantingmaterials for conservation.For seed-propagated crops (maizeand legumes), clean seed productionrequires planting accessions incontained screenhouses. Emergingplants are monitored for symptoms andeach plant is tested using diagnostictools for all known seed-transmittedviruses occurring in the territory wherethey were last grown. Plants that testpositive for virus and/or showing virus-like symptoms are destroyed. Seedsare harvested from the virus-negative,healthy-looking plants. Clean seedsare then deposited in the germplasmcollections. This work started in 2008,and so far over 4000 accessions oflegumes have been evaluated and cleanseed material produced have beenconserved in the genebank.For clonally propagated crops (cassava,yam and banana), production of clean Researcher in genebank. Photo by IITA. 27
  30. 30. In Kanti Rawal’s footsteps:wild cowpea from NigeriaRemy S. Pasquet (rpasquet@icipe.org), Dominique Dumet(d.dumet@cgiar.org), and Sunday E. Aladele (sundayaladele@yahoo.com)Cowpea, Vigna unguiculata(L.) Walp. is the majorlegume crop in the Africanlowlands. It is the mainprotein supply of half ofthe population in sub-Saharan Africa.Nigeria is the mostpopulous country in WestAfrica, and also producesthe largest amountof cowpea. Its urbanpopulation is growing inleaps and bounds, andthus, it is also importing alot of cowpea from all itsneighbors. Cowpea: dietary protein for millions in West Africa. PhotoCowpea is considered by by IITA.several authors as havingbeen domesticated inNigeria or within a larger Rawal traveled 38,000 Regarding Nigeria, Rawalarea including Nigeria (i.e., km around Nigeria and (1975) wrote in theVaillancourt and Weeden Niger. He collected wild abstract of his paper: “As1992). In addition, the cowpea accessions as well in the case with manyfirst wild cowpea accession as numerous accessions of cultivated species, Vignawas collected in northern domesticated cowpea. unguiculata (L.) Walp.Nigeria by J.M. Dalziel, has a wild form growinga British botanist, and According to his map (see next page), he in secondary foreststhis led Piper (1913) to collected wild cowpea in and derived savannahspropose the African origin 68 places (Rawal 1975). and a companionof cowpea1. Unfortunately, over the weed form adapted toTo some extent, this partly years, the passport data disturbed habitats suchexplains why Nigeria was of these accessions were as roadside ditchesthe first country surveyed lost and, today, the place and fields. Evidence offor cowpea accessions of collection is known for introgressive hybridizationby IITA’s then Genetic only four out of the 40 between weedy andResources Unit. Between accessions still maintained cultivated forms has1970 and 1973, Kanti at IITA. been presented. The1 The African origin of cowpea was proposed 50 years earlier, when authors were split between thosesupporting an African origin and those supporting an Indian origin. Piper, while successfully crossinga domesticated cowpea and a wild plant from Nigeria, definitely proved the African origin of cowpea.After 1913, the African origin of cowpea was not challenged anymore and definitely accepted.28
  31. 31. N i g E R Wild Colonizer weed Companion weedGeographic distribution of the wild, the colonizer weed, and the companion weed formsof V. unguiculata in Nigeria and Niger. The cowpeas are cultivated commercially in areasbetween latitudes 8°N and 15°N (Rawal 1975).zone of extensive natural first subspecies belongs to the diversity of cowpeahybridization corresponds the secondary gene pool and wild Vigna in theto the cultivation area of of cowpea and the second near future. To avoid thenorthern Nigeria and Niger to the primary gene pool. irreversible loss of Vignaand may well extend to However, since Rawal’s and to secure highly viableUpper Volta (now Burkina material is mostly lost2, Vigna diversity, the GlobalFaso) and Senegal.” the assessment of the Crop Diversity Trust in diversity of wild cowpea association with IITA andRawal gave very good from Nigeria is impossible Nigerias National Centredescriptions of what he in the absence of new for Genetic Resources andcalled the wild and weed collection missions in the Biotechnology (NACGRAB)forms. His wild forms country. organized a collectingwere samples of subsp. mission for wild Vignabaoulensis (A.Chev.) In addition, factors germplasm in 2010.Pasquet; the weed forms such as climate change, The mission coveredwere samples of subsp. increased incidence of 27,000 km in Nigeriaunguiculata var. spontanea pests and diseases, between 14 October and(Schweinf.) Pasquet. We cultural change, or the 7 December and collected(Pasquet and Padulosi in adoption of improved lines 260 accessions (242 ofpress) believe that the are also likely to affect var. spontanea and 18 of2 iiTA still holds 40 accessions, but this could be only one-third of the original number. 29