Paper Unleashing the potential of sweetpotato Working in Sub-Saharan Africa: Current challenges and way forward 2009-1 ISSN 0256-8748 Social Sciences Working Paper No. 2009 - 1 Paper Working Working Unleashing the potential of sweetpotato 3 in Sub-Saharan Africa: Current challenges and way forward Working Paper 1 Maria Andrade, Ian Barker, Donald Cole, Segundo Fuentes, Wolfgang Grüneberg, Regina Kapinga, Jürgen Kroschel, Ricardo Labarta, Berga Lemaga, Cornelia Loechl, Jan Low, Oscar Ortiz, Andreas Oswald, Graham Thiele International Potato Center (CIP) International Potato Center • Howard Elliott, John Lynam, International Consultants Harrison Kwame Dapaah Sweetpotato Breeder/Principal Research Scientist Crops Research Institute (CSIR), Ghana Robert O.M. Mwanga Head, Sweetpotato Research National Agricultural Research Organization (NARO), Uganda The Social Sciences Working Paper Series is intended to advance social science knowledge about production and utili- zation of potato, sweetpotato, and root and tuber crops in developing countries to encourage debate and exchange of ideas. The views expressed in the papers are those of the author(s) and do not necessarily reflect the official position of the International Potato Center. Comments are invited. Unleashing the potential of sweetpotato in Sub-Saharan Africa: Current challenges and way forward © International Potato Center (CIP), 2009 ISSN 0256-8748 4 CIP publications contribute important development information to the public arena. Readers are encouraged to quote or reproduce material from them in their own publications. As copyright holder CIP requests acknowledgement, and a copy of the publication where the citation or material appears. Please send a copy to the Communication and Public Awareness Department at the address below. International Potato Center Working Paper 1 P.O.Box 1558, Lima 12, Peru [email protected] • www.cipotato.org Produced by the CIP Communication and Public Awareness Department (CPAD) Correct citation: Andrade, M., Barker, I., Cole, D., Dapaah, H., Elliott, H., Fuentes, S., Grüneberg, W., Kapinga, R., Kroschel, J., Labarta, R., Lemaga, B., Loechl, C., Low, J., Lynam , J., Mwanga, R., Ortiz, O., Oswald, A. and Thiele, G. 2009. Unleashing the potential of sweetpotato in Sub- Saharan Africa: Current challenges and way forward. International International Potato Center • Potato Center (CIP), Lima, Peru. Working Paper 2009-1. 197 p. Editing Cathy Barker Layout Zandra Vásquez Printed in Peru by Comercial Gráfica Sucre Press run: 100 February 2009 Table of Contents Fore word .......................................................................................................................................................................vi Challenge Theme Paper 1: Sweetpotato Breeding............................................................................................ 1 Background ............................................................................................................................................................ 1 Principal Challenges ............................................................................................................................................ 8 Challenge 1.1. Limited breeding infrastructure................................................................................. 8 Challenge 1.2. Poorly developed breeding and selection methods ........................................11 Challenge 1.3. Lack of sweetpotato virus disease tolerance.......................................................24 Challenge 1.4. Lack of varieties adapted to the cold tropical highlands ................................26 Challenge 1.5. Lack of tolerant varieties.............................................................................................28 Challenge 1.6. Lack of non-sweet sweetpotato varieties.............................................................33 References....................................................................................................................................................39 Challenge Theme Paper 2: Sustainable Seed Systems...................................................................................43 Background ..........................................................................................................................................................43 Principal Challenges ..........................................................................................................................................44 Challenge 2.1. Efficient mechanism(s) for introducing and multiplying new improved varieties?...................................................................................................................................44 Challenge 2.2. Inadequate supplies of vines at the onset of the rains.....................................48 Challenge 2.3. Improving the role of sweetpotato in disaster relief and mitigation ..........50 Challenge 2.4. Assuring the quality of sweetpotato planting material for purchasers?....53 Challenge 2.5. Efficient and safe germplasm movement programs?.......................................57 Conclusion ............................................................................................................................................................59 References.............................................................................................................................................................61 Additional reading .............................................................................................................................................71 Challenge Theme Paper 3: Nutritional impact with orange-fleshed sweetpotato (OFSP).................73 Background ..........................................................................................................................................................73 Challenge 3.1. Increase the bioavailability of micronutrients in OFSP and retention during processing and storage .......................................................................................................................76 Challenge 3.2. Maximizing the nutritional impact of OFSP ..........................................................................81 Challenge 3.3. Maximize the role of OFSP in mitigating the situation of persons living with HIV/AIDS (PLWH)..............................................................................................................86 Challenge 3.4. Identifying cost-effective models of scaling out integrated OFSP programs............90 References.............................................................................................................................................................99 Challenge Theme Paper 4: Sweetpotato value chains.................................................................................106 Background ........................................................................................................................................................106 Principal Challenges ........................................................................................................................................108 Challenge 4.1. Limitations of size for sweetpotato markets......................................................108 Challenge 4.2. Perishability and availability....................................................................................113 Challenge 4.3. Processed sweetpotato products are mostly unknown in Sub-Saharan Africa..................................................................................................................................115 Challenge 4.4. Limited coordination among actors in sweetpotato value chain ..............118 Challenge 4.5. Potential of sweetpotato as an animal feed ......................................................124 Conclusion ..........................................................................................................................................................126 References...........................................................................................................................................................127 Challenge Theme Paper 5: Integrated Crop Management.........................................................................130 Background ........................................................................................................................................................130 iii Principal Challenges........................................................................................................................................133 Challenge 5.1. Improving crop management practices dependent on farmers’ objectives ..................................................................................................................................134 Challenge 5.2. Extending the supply period to meet demands for sweetpotato products......................................................................................................................................................137 Challenge 5.3. Managing the crop under moisture constraints ..............................................139 Challenge 5.4. Improving soil fertility management ...................................................................141 Challenge 5.5. Controlling the sweetpotato weevil.....................................................................143 Challenge 5.6. Scaling