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Publications

2019 SASHA Brief 24. Strengthening the SPHI community of practice: “A sweetpotato family, tremendously rewarding”.

Successfully held annual meetings for four technical community of practice (CoP) working groups over five, years with almost 1,000 participants (31% women) in total Sweetpotato for Profit and Health Initiative (SPHI) Technical Meeting held annually with over 100 participants and over 40 organizations participating during last two years (Fig. 1) Annual production of the Status of Sweetpotato in sub-Saharan Africa (SSA) report, to which SPHI Steering Committee members share their beneficiary statistics. As of July 2019, 6.2 million households have been reached. Revamping of the Sweetpotato Knowledge Portal, including a new Dashboard that tracks the number of beneficiaries by country and organization, the location and contacts of quality vine multipliers, and information on key traits of released varieties. Development of various tools to improve data collection, monitoring, and analysis for social scientists, breeders, and laboratory work flows and training on their use.

2019 SASHA Brief 23. Food and nutritional evaluation laboratory (FANEL): Growth towards a sustainable service unit.

Acquired and upgraded an Inductively Coupled Plasma Optical Emission Spectroscopy machine (ICP-OES) for mineral analysis, including an autosampler which enables high throughput analyses (Fig. 1). Research Associate Derick Malavi received training on operating the ICP-OES and X-Ray Fluorescence at the Maize Quality Laboratory, CIMMYT in Mexico. FANEL successfully registered for proficiency testing of our protocols with LGC Standards, an accredited proficiency testing laboratory based in the UK. Implemented the FANEL business plan to ensure sustainability as a service unit. Improved the functionality of FANEL-FLOW, an on-line system available via a web browser, to help improve workflow management within the FANEL.

2019 SASHA Brief 22. Potential business models and financial feasibility of selected medium-scale business enterprises for orange-fleshed sweetpotato (OFSP) value-added products.

Five potential and financially viable business models were examined for OFSP value-added products in the Kenyan context. These potential OFSP value-added products are cookies, cupcakes and mandazi (donuts), and OFSP purée for bakery products. However, the choice of products might differ in other regions based on market demand and cost of ingredients. The required minimum investment level varies between US$ 31,000 and 43,000 depending on the business model selected. The payback period varies between 1 to 2.8 years and average Return on Investment (RoI) is more than 100%.

2019 SASHA Brief 21. The development & utilization of a breakthrough product: orange-fleshed sweetpotato puree.

Orange-fleshed sweetpotato (OFSP) purée can be used to substitute wheat flour by 25-60% depending on the product, without affecting the quality of baking procedures. We developed a safe, vacuum-packed shelf-stable purée that lasts 3 months without refrigeration, using locally available preservatives. By carefully washing the roots, it is not necessary to peel them. This has enabled a high-fiber purée (Fig. 1) to be developed that significantly improves the profit margin for purée processors.

2019 SASHA Brief 20. Solar-powered storage in Mozambique: Lessons learned and way forward.

Design, installation and testing of a solar-powered storage facility (Fig.1) was conducted over four months in Marracuene, Mozambique using fresh roots of four varieties. The percentage of marketable root weight was above 70% of the initial weight at four months of cold storage in all the four varieties. There were no significant differences in dry matter, zinc, fructose, glucose, sucrose, and protein from one month to four months of storage.

2019 SASHA Brief 19. Strategies for storage of orange-fleshed sweetpotato in Sub-Saharan Africa to ensure supplies for processing: Lessons learnt and the way forward.

Two evaporatively cooled stores (Fig.1) with the capacity to each hold 5 tonnes of sweetpotato roots were constructed in Kenya, one run on mains power and the other on solar. Using the evaporative cooling system temperatures of 20-23°C were achieved and fresh sweetpotato storage trials kept 63-83 % of the roots of the variety Vita suitable for puree production relative to initial weight after 4 months of storage and 54-59% of the roots for the variety Kabode. A solar-powered standard refrigeration store was constructed from a shipping container, air conditioner and Coolbot to achieve storage temperatures of 15°C and curing temperatures of up to 30°C and humidification. Storage trials in this cooler store reduced sprouting and weevil infestation problems but suffered from higher rotting, with just 35-56 % of root material suitable for puree after 4 months. De-haulming prior to harvest improved root storability. Further work is needed to understand the impact of varietal differences, curing and storing conditions, air flow and air exchange rates in stores.

2019 SASHA Brief 18. Rapid field based diagnostic tool for the detection of sweetpotato viruses is now a reality.

Extensive testing of LAMP (Loop Mediated Isothermal Amplification) has shown a high sensitivity and specificity in detecting sweet potato feathery mottle virus (SPFMV), sweet potato chlorotic stunt virus (SPCSV), and begomoviruses comparable to using quantitative polymerase chain reaction (RT-QPCR). On-site detection of SPFMV, SPCSV, and begomoviruses was simple to perform in different geographical regions. LAMP assay has potential as a rapid diagnostic tool for SPFMV, SPCSV, and begomoviruses. At a current cost of $6.5 per assay, we anticipate the tool when used with bulked samples, which will be highly cost-competitive compared to biological, serological and molecular techniques.

2019 SASHA Brief 17. Are begomoviruses a threat to sweetpotato production in Sub-Saharan Africa?

Begomoviruses have progressively been reported to be infecting sweetpotatoes throughout the world. Despite showing few symptoms, limited studies have reported them to have a varying but significant impact on root quality and yield. A cultivar with moderate resistance to Sweet potato feathery mottle virus (SPFMV) and/or Sweet potato chlorotic stunt virus (SPCSV) had a yield reduction of 47% from of single infection of a begomovirus, in contrast to a SPVD susceptible cultivar, which was hardly affected by it.

2019 SASHA Brief 16. Sweetpotato seed systems community of practice – what are we learning? What are we practicing?

Nine consultations were held from April 2015 to May 2019, with participation from diverse actors in the seed system i.e. researchers from CIP and NARIs, NGOs implementing sweetpotato projects, regulators, seed producers and farmers. Participants say that the community of practice (CoP) is the best way to experience sharing, learn new practices and increase interaction between researchers and practitioners. An online survey was conducted in May 2019. All respondents listed new knowledge and skills that they have learnt, and the majority reported on new technologies that they have tried in their contexts.

2019 SASHA Brief 15. Towards sustainable production of pre-basic seeds in Nigeria (2015-2019).

Strengthened the capacity of national partners (National Root Crops Research Institute (NRCRI) and Bayero University(BUK)) to produce and manage high quality planting material of breeder, pre-basic and basic seeds: 21 net tunnels, three screen houses, and irrigation facilities were established (Fig. 1). Established, built and strengthened the capacity of Decentralized Vine Multipliers (DVMs) and NGO partners (Kolpin and Linto farms) to commercialize the production of high quality seeds; Net tunnel and Triple S technologies were extended to partners.

2019 SASHA Brief 14. What motivates vine multipliers to continue once project support has ended? A case study from the Lake Zone, Tanzania.

In the Lake Zone, Tanzania, between 2009-2012, 88 decentralized vine multipliers (DVMs) were established by the Marando Bora project. Five years later, the follow up study traced 81 of the DVMs. 40% of the DVMs had sold planting material of Marando Bora varieties in the last year; a further 16% had maintained the improved varieties for own use. The percentages of DVMs retaining different improved varieties were: Polista: 48%; Kabode: 34% Ukerewe: 23%; Ejumula: 12%; and Jewel: 11%. Depending on variety, between 9-21% of DVMs had obtained replacement materials.

2019 SASHA Brief 13. Early generation seed production for roots, tubers and bananas is financially viable for private sector seed companies in East Africa.

CIP conducted a financial feasibility study for a private seed company engaged in early generation seed (EGS) production for root, tuber and banana crops. The study showed that the business is financially viable in the long-run based on the existing business for production and sale of banana, cassava, sweetpotato and potato planting materials. The business required an initial total investment of US$1 million and running costs of US$0.15 million during an eight-month establishment period. The payback period for this level of investment would be between three to seven years, with an average annual return of between 34-70%. Inclusion of sweetpotato in the business increased its financial viability over time

2019 SASHA Brief 12. A new method for estimating sweetpotato early generation seed requirements to supply commercial and institutional markets.

A user-friendly tool to estimate the requirements for Early Generation Sweetpotato Seed (EGS) is now available for use by public sector seed producers. The method was first used in Uganda to estimate the seed requirement by root producers for quality seed of improved varieties; then estimates of the number of basic seed multipliers this will require; and finally, the amount of pre-basic cuttings and tissue culture plantlets to be produced. Results indicate a need to treble the existing pre-basic seed production capacity; decentralize pre-basic screenhouse capacity to get broader national coverage; improve screenhouse design and utilization to increase efficiency and reduce the cost of pre-basic seed production. Scaling EGS production and linkages through the chain will only be successful if there is an expansion in the root markets driving demand for quality seed.

2019 SASHA Brief 11. Bridging the gap between pre-basic seed producers and decentralized multipliers for a sustainable sweetpotato seed system in Tanzania.

A study was conducted to understand the economic sustainability of basic seed enterprises to bridge the gap between pre-basic seed producers and decentralized vine multipliers. Four commercial seed multipliers were supported on a 2:3 (multiplier: CIP) cost-share basis. They were trained in entrepreneurial skills, marketing, business planning, and quality seed production. Business plans are now under implementation, and basic and pre-basic seed producers are now well-linked. The basic seed business required an initial investment of US$ 6,241, for a multiplication period of 12 months. US$ 1,314 is for the screenhouse to conserve quality seed. The payback period is one to two years, with an average annual return of 23-52%.