Orange-fleshed sweetpotato (OFSP) is a rich plant-based source of beta-carotene, which the body converts into vitamin A. In sub-Saharan Africa, sweetpotato is known as a food security crop but most varieties grown are high dry matter white-fleshed types, lacking beta-carotene. In 1995, researchers recognized the potential of OFSP varieties to address widespread vitamin A deficiency in SSA using an integrated agriculture-nutrition approach. With their partners, they confronted conventional wisdom concerning food-based approaches and institutional barriers, to build the evidence base and breed 42 OFSP varieties adapted to farmer needs and consumer preferences. Subsequently, a multi-partner, multi-donor initiative, launched in 2009, has already reached 2.8 million households. This review summarizes that effort describing how the changing policy environment influenced the process.

In sub-Saharan Africa, more than 40% of children under five years of age suffer from vitamin A deficiency. Among several interventions in place to address vitamin A deficiency is biofortification, breeding vitamin A into key staple crops. Staple crops biofortified with beta-carotene, the precursor to vitamin A, are orange in color. Given the natural occurrence of high levels of beta-carotene in many sweet potato varieties, breeding progress for biofortified orange sweet potato (OSP) has been much faster than for the other vitamin A enhanced staples. Nearly 3 million households have been reached with OSP. This paper reviews key factors influencing the uptake of OSP, the breeding investment, five key delivery approaches that have been tested in the region and efforts to broaden government and other stakeholder engagement.

The enhancement of sweet potato and maize with provitamin A carotenoids has been part of HarvestPlus's research continuum since the formation of the biofortification project. This review includes case studies of biofortification strategies used for sweet potato in Uganda and orange maize in Zambia. The current status of the science and release of biofortified varieties was reviewed by three scientists who were part of the HarvestPlus program for more than a decade with input from a scientist who experienced orange maize dissemination in Zambia. High ␤-carotene varieties of sweet potato were introduced into South Africa and Mozambique, and efficacy and effectiveness studies, respectively, showed promise to improve vitamin A status, followed by dissemination efforts in Uganda. A randomized, controlled effectiveness trial tested extension models to promote sweet potato and assessed vitamin A intake among Ugandans. Orange maize breeding was initially a challenge, but considering that the carotenoid biosynthetic pathway was present in maize germplasm, breeders quickly bred higher amounts of provitamin A into the maize that was ultimately released in Zambia. Initial resistance occurred because orange maize was associated with yellow maize, which had negative connotations associated with food aid and animal feed, and consumers preferred white maize. Currently, both orange crops are available on the market.

Additional index words. Ipomoea batatas, sweetpotato virus disease, alternaria bataticola blight, provitamin A Two sweetpotato [Ipomoea batatas L. (Lam.)] cultivars, NASPOT 12 O (Namulonge sweetpotato 12 orange-fleshed) and NASPOT 13 O (Namulonge sweetpotato 13 orange-fleshed) were approved for release by the Ugandan Plant Variety Release Committee (UPVRC) in Nov. 2013(Ssemakula et al., 2013. This brings to 22, the number of sweetpotato cultivars officially released between 1999 and 2013 by the National Sweetpotato Program in Uganda (Mwanga et al., 2011;Ssemakula et al., 2013). The two cultivars herein described and released in 2013, have high average storage root yields, 43.1 t • ha -1 ('NASPOT 12 O') and 27.8 t • ha -1 ('NASPOT 13 O') on station, and 14.9 t • ha -1 ('NASPOT 12 O') and 9.7 t • ha -1 ('NASPOT 13 O') on farm compared with the national on-farm average for Uganda of 4.5 t • ha -1 (FAOSTAT 2010;Low et al., 2009). The cultivars have acceptable root shape, high dry matter content (DMC) (>30%) with

During the past 15 years, significant investments have been made in the development and promotion of orange-fleshed sweetpotato (OFSP) varieties in sub-Saharan Africa (SSA) due to their high β-carotene contents and thus, their potential to contribute towards reducing vitamin A deficiency. As the dominant varieties in SSA are white-fleshed, lacking in β-carotene, the introduction of OFSP means that producers and consumers need to accept the very visible change in colour along with any other trait differences. We first review the building of the evidence base for OFSP in SSA, summarizing the key lessons learned to date, focusing on interventions aiming for impact on vitamin A intakes or status. Second, we review the state of knowledge concerning how to maximize the nutritional value of OFSP when processed and identify appropriate entry points to reach rural and urban consumers. Third, we explore how the health sector and private-sector marketing firms are tackling behavioural change and based on this accumulated multi-sector experience develop improved recommendations to guide practitioners on how they should approach reaching consumers. Finally, we pinpoint opportunities to enable the successful scaling out of OFSP adoption and utilization and identify areas of research needed to address remaining knowledge gaps. In developing OFSP-focused food-based approaches, several key questions are addressed: (i) Are OFSP varieties competitive with existing local varieties?; (ii) Do producers and consumers accept a variety with a distinct colour difference?; (iii) What does it take to get proper utilization of OFSP at the household and the young child level?; (iv) What are the key nutrition messages?; and (v) What do we need to do to break into rural and urban markets? We also examine the best techniques for assessing micronutrient contents of OFSP and its impact on status, the minimum amount of fat consumption linked to OFSP consumption and the bioaccessibility of OFSP processed in different ways. After reviewing how other sectors are approaching behavioural change, we propose 12 key recommendations on how to approach rural households and present dominant factors likely to influence urban consumer behaviour. The current policy environment is very favourable to integrated agriculture-nutrition interventions, and the Scaling Up Nutrition (SUN) movement emerges as the most promising opportunity for OFSP integration.