Scaling Readiness of Biofortified Root, Tuber, and Banana Crops for Africa

Abstract

This chapter describes the degree of readiness and use of biofortified root, tuber, and banana (RT&B) crops: sweetpotato, cassava, banana (cooking and dessert types), and potato. Efforts to develop and utilize orange-fleshed sweetpotato (OFSP), yellow cassava (VAC), and vitamin A banana/plantain (VAB) have been focused heavily in sub-Saharan Africa (SSA), where 48% of the children under 5 years of age are vitamin A-deficient. Iron-biofortified potato is still under development, and a recent study found high levels of bioavailability (28.4%) in a yellow-fleshed cultivar (Fig. 17.1). To date, adapted VAB varieties have been piloted in East Africa, and OFSP and VAC have scaled to 8.5 million households. The scaling readiness framework is applied to innovation packages underlying those scaling efforts to shed light on how scaling is progressing and identify remaining bottlenecks. Women dominate RT&B production in SSA, and women and young children are most at risk of micronutrient deficiencies; hence women’s access to technologies was prioritized. Lessons learned from these scaling efforts are discussed, with the goal of accelerating the scaling readiness process for other biofortified RTB crops. Implementing gender-responsive innovation packages has been critical for reaching key nutrition and income goals. Diverse partnerships with public and private sector players and investing in advocacy for an adequate enabling environment were critical for achieving use at scale. Future scaling will depend on more nutritious sustainable food systems being at the forefront, supported by continued improvement in breeding methodologies to adapt to climate change and enhance multiple nutrient targets more quickly and to increase investment in the input and marketing infrastructure that vegetatively propagated crops require.

1 Introduction

Poor households dispense 60–70% of their total income on food (Bouis et al. 2020). Just rice, wheat, and maize provide at least 40% of global calories (FAO 2016). Roots, tubers, and bananas (RT&B) are associated with more localized supply chains than grains and in sub-Saharan Africa (SSA) provide more than 50% of calories in several countries (Petsakos et al. 2019).

Biofortification is the innovative concept to enhance the micronutrient content of food staples as a cost-effective, sustainable way to deliver key micronutrients, especially to the poor. This can be achieved through conventional breeding, genetic engineering, or fertilization practice (Bouis et al. 2020). A highly diversified diet is the best way to get micronutrients, but cost and access frequently undermine this goal. Biofortification, industrial food fortification, and nutrient supplementation programs are complementary strategies used to target those most at risk of micronutrient deficiencies. Whereas capsule supplementation and premix used for fortification depend on importation and passive reception by target populations, biofortified crops are produced within a country. Scaling of biofortified crops depends on proactive uptake of new varieties by producers and consumers and the generation of additional livelihood opportunities.

An estimated 1.5–2 billion people suffer from micronutrient deficiencies or “hidden hunger” (FAO et al. 2018). Iron, zinc, vitamin A, and iodine are the most widespread and severe deficiencies. Young children and women of reproductive age are most vulnerable to micronutrient deficiencies because they have greater micronutrient needs due to rapid growth and/or reproductive functions (Bailey et al. 2015). The World Bank estimated that macro- and micronutrient deficiencies underpin a 2–3% loss in annual global economic productivity (World Bank 2006). As sources of key macro- and micronutrients, biofortified staples are clear remedies to these challenges. In 2008, the Copenhagen Consensus Center ranked biofortification fifth among cost-effective solutions for global world problems (Meenakshi 2008).

Work on biofortification began in the 1990s, led by researchers in the CGIAR international agricultural centers (Bouis and Saltzman 2017; Low et al. 2017). Highlights during the past two decades include:

• From 2000 to 2009, significant progress was made in breeding and efficacy studies, convincingly demonstrating that biofortified crops could impact human health cost-effectively.

• In 2010, efforts began to intensify scaling of released biofortified varieties.

• By the end of 2019, 340 varieties of 12 biofortified crops had been released in 40 lower- and middle-income countries (LMICs).

• HarvestPlus-led delivery efforts for iron beans, orange-fleshed sweetpotato (OFSP), vitamin A orange maize, zinc rice, zinc wheat, and iron pearl millet successfully reached 8.5 million farming households, while 6.8 million farming households received OFSP through partners participating in the Sweetpotato Profit and Health Initiative (SPHI) (Fig. 17.2), co-led by the International Potato Center (CIP) and the Forum for Agricultural Research in Africa (Bouis et al. 2020).

  Fig. 17.2

  

  Participants at the 2018 SPHI Annual Meeting, held in Nairobi, Kenya. (Credit: F. Njung’e/CIP)

• By 2019, 1.7 million Nigerians were growing vitamin A cassava varieties in 26 states (Foley et al. 2021).

• In addition, other nongovernmental and governmental bodies were distributing biofortified crops whose reach was not captured by monitoring organizations.

Released varieties to date have all been conventionally bred, building on naturally occurring variations in target micronutrients in these staples. Recognition of multi-sectoral biofortification efforts included the 2016 World Food Prize to Howarth Bouis, the Director of HarvestPlus, and CIP scientists Maria Andrade, Robert Mwanga, and Jan Low for their OFSP work.

With respect to RT&B, breeding has focused on sweetpotato, cassava, potato, and banana. Increasing levels of provitamin A carotenoids, which the body converts into vitamin A, has been the priority for sweetpotato, cassava, and banana, while enhancing iron and zinc content has been the focus for potato. Since 2014, a major breeding effort is underway to increase iron content in OFSP varieties. Although a critical staple in West Africa, yam (Dioscorea spp.) lacked sufficient variation in any of these three micronutrients to warrant any conventional breeding investment.

The objective of this chapter is to reflect critically on where biofortified RT&B crops are concerning their development and utilization at scale. First, we will examine progress made in meeting breeding targets and review expected impacts based on ex ante studies. Second, we will present and apply the scaling readiness approach (Sartas et al. 2020) to the most advanced of RT&B crops in use: orange-fleshed sweetpotato (OFSP), yellow-fleshed vitamin A cassava (VAC), and vitamin A banana (VAB), and highlight lessons learned through a gender lens because RT&B crops are widely grown by women in SSA, but women often face constraints in benefitting from new technologies. We expect these lessons to facilitate the nascent scaling efforts of VAB and iron-biofortified potato (IP). Finally, we discuss the ways forward in light of global realities driven by climate change, the current state of the food system, and advances in breeding methods.

2 Status of Biofortified Crop Variety Development

2.1 Achieving Target Levels and Bioavailability Evidence

During the concept development of biofortification, target levels were set by a multidisciplinary working group in 2005 with the intention of achieving a measurable impact on health for children and women of childbearing age (Hotz and McClafferty 2007). Target levels combine a context-specific micronutrient baseline level measured in commercial crops, with target increments to be added to achieve a required contribution to the estimated average requirement (EAR) from the biofortified crop. Target increments are adjusted for per capita intake, retention (losses during processing, storage, and cooking), and bioavailability (Bouis et al. 2020). Hence, target increments can be achieved by breeding for higher micronutrient concentration, increasing bioavailability and increasing retention. In addition to exploiting genotypic differences in retention in breeding, food technology has a significant role in increasing provitamin A retention. A negative effect of climate change on minerals and protein may require gradually increasing target increments for minerals in particular.

Cumulatively, more than 175 biofortified varieties of four RT&B crops have been released in more than 30 countries with a heavy emphasis on SSA (Bouis et al. 2020). Candidate biofortified varieties across the RT&B crops are being evaluated for release in an additional 20 countries (Table 17.1).

Table 17.1 Summary of countries where biofortified RT&B crops are released or under testing, target levels set, and bioaccessibility, bioavailability, and efficacy studies completed as of 2020

To date, OFSP is the biofortified RTB most in use, followed by VAC. VAB is still at the pilot stage and IP under development.

Orange-fleshed sweetpotato (OFSP)

In OFSP the intensity of the orange color reflects the amount of beta-carotene present, and 80% of the carotenoids present are beta-carotene (Fig. 17.1). Average beta-carotene values among OFSP clones at CIP-Peru was 144 μg/g dwb, with a maximum value of 1220 μg/g dwb, meaning many clones that exceeded beta-carotene target levels were available to draw from. The breeding challenge has been to combine the beta-carotene trait with other traits relevant for adoption by adult farmers, namely, high dry matter and high starch contents, resistance to viruses, and, where needed, tolerance to drought. The development and deployment of the accelerated breeding scheme, implemented by CIP and 14 national programs, enabled the breeding cycle to be reduced from 8–10 to 4–5 years (Andrade et al. 2017). Between 2009 and 2020, 62 OFSP varieties bred in Africa were released.

Starting in 2014, CIP began breeding for a “doubly biofortified sweetpotato” with the goal of having high-iron, high-beta-carotene varieties. The positive genetic association between iron, zinc, and beta-carotene supports this effort, but genetic variation in iron and zinc content within the germplasm is much less available, requiring more cycles of breeding to reach target levels. A recent study found that bioavailability of Fe in OFSP was 8.1% in women with low Fe status and just 4.0% in women with adequate Fe status (Jongstra et al. 2020). Additional breeding cycles will be required to reach target levels for Fe biofortification.

Vitamin A cassava (VAC)

The nutritional quality of cassava roots is low as roots contain mainly carbohydrates and trace elements of other micronutrients (Ceballos et al. 2017). Screening of germplasm accessions (2003–2008) found ranges of 0–19 ppm (fwb) provitamin A in roots of existing cassava varieties but good heritability of carotenoid content in roots, which encouraged breeders to proceed with biofortification (Ilona et al. 2017). Around 62% of the total carotenoids on average were all-trans beta-carotene, the most bioaccessible form of provitamin A (Ceballos et al. 2017). Two CGIAR centers collaborate in the VAC breeding effort: CIAT to generate high provitamin A sources via rapid cycling in pre-breeding and to provide in vitro clones and seed populations to the International Institute for Tropical Agriculture (IITA) for use in their breeding programs targeting African countries. As with OFSP, the goal is to have high-yielding varieties with high dry matter and high-beta-carotene content. In VAC, carotenoid concentrations are much higher in the leaves than in roots, while the opposite is true for OFSP.

Three first-wave VAC with 6–8 ppm provitamin A were released in 2011. Three second-wave varieties with up to 11 ppm were released in 2014. More than 50 VAC varieties are now under evaluation in several countries to identify those that are agronomically competitive for third-wave release (Fig. 17.1). The top five leads have more than 15 ppm, the target increment (Ilona et al. 2017).

Iron potato (IP)

Potato biofortification efforts at CIP for the last 17 years have focused on iron and zinc. Breeding diploids can accelerate genetic gain. Evaluation of three cycles of recurrent selection from crosses at the diploid level revealed high heritability (0.81 for both iron and zinc), and genetic gains above 29% for iron and 26% for zinc have been demonstrated (Amoros et al. 2020). However, diploids expressed lower yield compared to local varieties in Africa (Rwanda and Ethiopia) and Asia (Nepal, Bhutan, and India). These results prompted a new series of trials in Ethiopia, Kenya, and Rwanda in 2019/2020 with 50 biofortified tetraploid clones with consumer-preferred skin and flesh colors that are also late blight- and virus-resistant. Promising results from multilocation trials indicate the feasibility of a release of tetraploid potatoes in East Africa by 2022 (Fig. 17.3).

Fig. 17.3

Farmers are always involved in assessing the performance and taste of potential new varieties (clones) during multilocational trials. (Credit: P. Demo/CIP)

Results from a human iron bioavailability study (Jongstra et al. 2020) reveal remarkably high iron absorption from yellow-fleshed potatoes (28.4%) in women from the Peruvian Andes, highlighting the potential of biofortified potatoes to contribute to increased iron intakes. Lower iron bioavailability in the purple-fleshed potato (13%) is attributed to the high levels of phenolics, important inhibitors of iron absorption (Fig. 17.1). Given typical consumption levels of 500 g daily of potato by women in highland areas of Peru, the yellow-fleshed or purple-fleshed potato studied cover about 33% of the daily absorbed iron requirement for women of reproductive age. The bioaccessibility and bioavailability of zinc has not yet been determined, but zinc levels increase as iron is selected for.

Vitamin A banana

Conventional breeding of banana (Musa spp.) is difficult and expensive due to the long crop cycle as most commercial varieties are sterile triploids and have high cross incompatibility among fertile groups (Amah et al. 2019). Values of four boiled local cultivars in DR Congo provided vitamin A levels of 22.3–173 retinol activity equivalent (RAE) μg/100 g fwb (Ekesa et al. 2012a). Hence, the 14-year effort (2006–2019) in four East and Central African countries (Tanzania, Uganda, Burundi, DR Congo) has focused on selecting promising, more carotenoid-rich cultivars from 400 pre-screened cultivars from other countries (Fig. 17.1). About half of their carotenoid content is beta-carotene (retinol equivalence of 12:1) and the other half alpha-carotenoids (retinol equivalence of 24:1). As of March 2020, seven cultivars, from Ghana, Papua New Guinea, the Philippines, Hawaii, and Indonesia have demonstrated potential to perform well within East and Central Africa (Fongar et al. 2020) (Fig. 17.4). Sensory testing with local farmers revealed that 5 of the 15 tested cultivars have acceptable taste (Ekesa et al. 2017). Hence, pilot dissemination efforts have focused on six of the cultivars (Apantu, Bira, Lahi, Pelipita, Muracho, and Pisang Papan) in Burundi and DR Congo. By the end of 2019, nearly 13,000 farmers had been reached, of whom 61% were women (Fongar et al. 2020).

Fig. 17.4

Banana trial for selecting promising varieties in Burundi. (Credit: A. Simbare/Alliance Bioversity-CIAT)

Given the challenges in conventional breeding, a breeding effort started in 2007 is using genetic modification techniques to biofortify cooking bananas. Implemented by Queensland University of Technology in Australia and the National Agricultural Research Organisation of Uganda, the Banana21 project has incorporated a gene effective at increasing provitamin A content obtained from high provitamin A carotenoid Fei banana “Asupina” (from Papua New Guinea) into M9 hybrid and East African Highland bananas (Amah et al. 2019). Activities include laboratory work and field trials in Uganda and Australia and a nutrition study in the USA. These bananas may be ready for use in 2021. IITA has also recently incorporated high provitamin A carotenoid diploids from Papua New Guinea into their plantain breeding program (Amah et al. 2019).

2.2 Influence of Micronutrient Retention During Processing

For RT&B, dominant forms of consumption are driven by the perishability of the crop postharvest. Both sweetpotato and cassava can be “stored” in ground for considerable periods of time and harvested piecemeal. In contrast, potato tubers need to be harvested when they reach maturity. Banana (including East African highland bananas) plantains and dessert bananas are often harvested and used while green but also used when partially or fully ripened. In eight VAB cultivars, mean total provitamin A carotenoids increased substantially from 560–4680 mg/100 g fwb in unripe fruit to 1680–10,630 mg/100 g fwb in ripe fruit (Ekesa et al. 2015).

Once harvested, cassava roots have very limited shelf life and must be processed into a dried, storable form (Fig. 17.5). Fresh sweetpotato roots, without curing, can last 1–3 weeks, and the dominant form of consumption is boiled or steamed roots, with roasted and fried roots consumed to a lesser extent. Non-diseased potato tubers can store for months under dark and cool conditions; their dominant form of consumption in SSA is also boiled or steamed, with fried consumption concentrated in urban areas. Green plantains are boiled, while ripe plantains are typically fried. Ripened sweet bananas are eaten raw as a fruit.

Fig. 17.5

Preparing vitamin A cassava roots for processing in Nigeria. (Credit: HarvestPlus)

In the human intestine, carotenoids like beta-carotene and alpha-carotene are cleaved to retinol (vitamin A). Beta-carotene has two times higher vitamin A activity (12:1 retinol conversion) than other carotenoids (24:1) (Ishiguro 2019). Releasing nutrients from the food matrix specific to each crop during digestion makes them bioaccessible. Then a person’s health status and presence of other substances, like fat, determines the amount of nutrient actually absorbed by the intestines, reflecting the product’s bioavailability.

Exposure to light, air, and heat can all contribute to the degradation of provitamin A carotenoids with levels varying considerably by genotype. De Moura et al. (2015) reported that for VAC and OFSP, boiling and steaming had much higher retention rates of vitamin A (80–98%) compared to roasting or baking (30–70%) and frying (18–54%). A significant concern for VAC in West Africa is that most cassava is consumed as gari, a fermented granular flour, pressed and roasted into granules – called fufu – fermented roots that are boiled or steamed and then pounded (Fig. 17.6). While apparent retention in fufu range from 44 to over 100%, gari had the lowest levels of retention (10–30%). Taleon et al. (2018) determined that true total carotenoid in fufu was only 0.8–3.1%. Reaching the biofortification vitamin A target with VAC gari only works because average per capita consumption levels of cassava by women in rural West Africa is high – 900 g per capita daily (fwb) (De Moura et al. 2015). By contrast, just 100–125 g of any OFSP root, regardless of how it is prepared, will meet 100% of the vitamin A EAR for young children.

Fig. 17.6

Women in Nigeria use vitamin A cassava to make fufu. (Credit: HarvestPlus)

Cooking bananas enhances the release of carotenoids from plastids, with amounts concentrated through water loss (Amah et al. 2019). The bioaccessibility of carotenoids from boiled bananas varies by cultivar and ranged from 10% to 32% among three cultivars examined in DR Congo (Ekesa et al. 2012b). Fat does enhance bioaccessibility in OFSP (Tumuhimbise et al. 2009) and banana (Ekesa et al. 2012b).

Retention loss during storage is also of interest, as ability to store helps to address seasonal food insecurity. For VAC, drying in the shade demonstrated superior carotenoid retention (59%) than drying in the direct sun (27–56%). For OFSP, retention levels (66–96%) did not vary significantly by drying method. At issue is the substantial loss of carotenoids that can occur during subsequent storage of dried VAC or OFSP under tropical ambient conditions (Bechoff et al. 2011; Chávez et al. 2007).

Given this challenge CIP has focused on fresh sweetpotato root storage. Under commercial storage conditions in the USA, the beta-carotene content of the orange-fleshed variety Covington increased from 253 μg/g (dwb) to 260 μg/g after 4 months of storage and 291 μg/g by the end of 8 months (Grace et al. 2014). In the African context, Tumuhimbise et al. (2010) cured roots “naturally” by spreading them on the ground under the sun for 4 days (26–29 °C; 80–95% RH) prior to storage. Roots stored in pits retained higher beta-carotene content compared to roots stored in sawdust, dark rooms, or ambient conditions. In all methods, OFSP varieties maintained more than 100 μg/g dwb after 4 months of storage.

Shelf-stable OFSP purée (steamed and mashed sweetpotato) has been an integral part of the innovation package designed to enhance incomes while improving the vitamin A content of the processed product (Fig. 17.7). CIP developed a vacuum-packed shelf-stable purée that is safe for storage up to 3 months at temperatures ≤ 25 °C using locally available preservatives (Musyoka 2017) and retains sufficient beta-carotene. New markets for OFSP roots would drive expansion of production, concurrently increasing levels of consumption.

Fig. 17.7

Making OFSP puree at Organi Ltd in Kenya – a partial substitute for wheat flour in baking. (Credit: J. Low/CIP)

3 Expected Impact Based on Ex Ante Studies

Ex ante simulation models have been used to estimate the potential cost-effectiveness of biofortification, based on disability-adjusted life years (DALYs) saved, or reduced prevalence of inadequate micronutrient intake. Lividini et al. (2018) reviewed 30 ex ante studies on biofortified crops from 2002 through 2015, describing 4 different categories of analysis. Since 2006, there has been increasing consideration of both supply and demand for biofortified crops, utilizing widely available household expenditure and consumption surveys. Several studies indicate that biofortification has greater impact among women and children in rural than in urban areas and benefits lower income groups more than higher income groups.

Biofortification emerges as a highly cost-effective micronutrient intervention, based on the World Bank’s (2020) threshold of $270 for cost-effectiveness, when the crop being biofortified is widely consumed and the amount of bioavailable target micronutrient is sufficient to address the deficiency (Bouis et al. 2020). In the case of OFSP and VAB, the levels of carotenoids in orange types are quite high, making the key issues the extent of their adoption by farmers and the frequency and amount of consumption. In the case of VAC, IP and iron-biofortified OFSP, reaching target levels through repeated breeding cycles is requisite, in addition to considering and consumption levels and micronutrient bioavailability.

For example, one ex ante study for Nigeria assumed 30% of replacement of existing cassava with VAC (varieties with 8 ppm vitamin A content) and found the cost per DALY saved of $1.01, driven by the large amounts of cassava consumed by adult women. This was much lower than $50 per DALY saved for sugar fortification with vitamin A and $52 per DALY saved with supplementation (Ilona et al. 2017). Thus, these results indicate that VAC is particularly appropriate for reaching rural populations.

4 Innovation Package Design and the Scaling Readiness Framework

4.1 Concept of Scaling Readiness of Innovation Packages

“Innovation readiness” refers to the demonstrated capacity of an innovation to fulfill its contribution to development outcomes in specific locations, presented in nine stages showing progress from an untested idea (score 0) to a fully mature proven innovation (score 9). “Innovation use” indicates the level of use of the innovation or innovation package by the project members, partners, and society. Progressively broader levels of use begin with the intervention team who develop the innovation (score 0) until reaching widespread use by users who are completely unconnected with the team or their partners (score 9).

“Scaling readiness (SR)” of an innovation is a function of innovation readiness level (from 0 to 9) and innovation use (from 0 to 9). Table 17.2 provides summary definitions for each level of readiness and use (adapted from Sartas et al. 2020). The final SR score is a combination of the lowest score from two distinct components. Hence, the maximum possible SR score is 81 (9x9).

Table 17.2 Summary definition of levels of innovation readiness and use (Sartas et al. 2020)

4.2 Innovation Package Design Targeting Specific Livelihood Outcomes

Sartas et al. (2020) stress that scaling of any specific core innovation, such as a biofortified variety (BV), requires a set of complementary systems that typically entail additional innovations to enable uptake. This collection of innovations is described as an innovation package. Package composition is driven by the desired ultimate outcomes and the specific scaling environment.

BVs can contribute to multiple nutrition and livelihoods outcomes. These are combined in theory of change and implementation plans of research for development (R4D) programs to maximize overall benefits. For ease of interpretation, we distill this diverse set of scaling efforts into separate innovation packages that address three major development outcomes: (1) improved nutrition, (2) improved food and nutrition security, and (3) improved incomes. Efforts to improve nutritional status have been focused on those most at risk of vitamin A deficiency – women and young children. In contrast, improved food and nutrition security efforts typically target rural households. Targeting for improved incomes varies, and increased commercialization efforts for fresh products focus on rural households, or, specifically on women to assure they benefit from commercialization as farmers, traders, or processors.

Common to all three innovation packages is the core innovation of developing BVs that are acceptable to the target group(s) of each outcome. Strong evidence has demonstrated that any BV used must yield on average at least as much as the dominant local variety to be permanently adopted (Low et al. 2017). To get uptake of these varieties, positive field performance must be demonstrated and linked, typically, to on-farm trials associated with varietal testing or post-release demonstration plots. The innovation packages shown in Tables 17.3, 17.4, and 17.5 are based on actual implementation experience over the past decade. The co-authors of this article, in consultation with the colleagues within their organizations, have reviewed package components and applied the SR scales for country specific settings.

Table 17.3 Innovation packages and their scaling readiness assessments for biofortified vitamin A-rich orange-fleshed sweetpotato (maximum possible score for each readiness or use component is 9)

Table 17.4 Scaling readiness assessment for biofortified vitamin A cassava

Table 17.5 Scaling readiness assessment for vitamin A-rich banana/plantain in East and Central Africa

A significant complementary innovation is the pre-basic seed system, which most often falls under the domain of national research programs for RT&B crops. High-quality, disease-free starter stock (tissue culture plantlets and screen house protected cuttings) is essential for breeding programs and maximizing yields (Fig. 17.8).

Fig. 17.8

A Rwanda Agriculture Board tissue culture laboratory in Rubona produces quality sweetpotato plantlets. (Credit: J. Low/CIP)

Further multiplications of planting materials to increase quantities available for distribution to farmers are also complementary innovations that vary in design. Productivity and crop quality will be enhanced if complementary training on agronomic, harvesting, vine conservation, and/or other postharvest techniques is provided. Because crops biofortified for vitamin A have a distinct orange or yellow color, another complementary innovation is a demand creation campaign to build awareness about the nutritional value of the BV among end users (Low et al. 2015). Considerable investment has been made in developing and testing approaches about how to advocate both at the community level and policy level to ensure that biofortified crops are integrated into relevant national government and regional policies of agriculture, food security, and nutrition (Covic et al. 2017). The development of a strong enabling environment is critical for scaling, as government support facilitates expansion of the innovation package(s) and supplementary donor investment.

In describing innovation package components for the three distinct outcomes described, the most widely scaled BV, OFSP, will be used as an example. Packages for VAC and VAB will be presented in the subsequent section where the scaling readiness and use scores are applied and explained.

The OFSP innovation packages for each outcome are shown in Table 17.3. Innovation Package #1, with eight components, focuses on improving nutrition among children under 5 years of age and pregnant and lactating women (Fig. 17.9). Essential to this package are two complementary nutrition components. The first is a nutrition awareness campaign built on generating awareness locally and nationally about the importance of vitamin A for good health and the high vitamin A content of OFSP, as well as other good sources of vitamin A available in the country. These campaigns have used radio, market-based promotions (signs, billboards), messages on orange-colored promotion materials (cloth, hats, t-shirts, vehicles), videos, social media, brochures, and television spots to inform the public and policy makers. Several prominent policy makers in SSA have become advocates themselves (Fig. 17.10). The second is a community-based nutrition-focused behavioral change model. Research has established that facilitated group sessions of 25–30 households meeting monthly for 6–12 months to share knowledge about better dietary and health practices at the household level and feeding practices for young children resulted in improved vitamin A intakes and vitamin A statuses among young children and their mothers (Girard et al. 2017; Hotz et al. 2012; Low et al. 2007). The use of trained community-based health workers or volunteers has been integral to the success of this approach (Girard et al. 2021) in four SSA countries (Kenya, Ethiopia, Mozambique, Tanzania).

Fig. 17.9

OFSP is appreciated by all household members but especially by young children. (Credit: Helen Keller International)

Fig. 17.10

Shown at a promotional event for OFSP in the Volta Region: Nan and Kofi Annan are key advocates for using OFSP to improve diet quality in Ghana. (Credit: Tessa Smit/CIP)

In Innovation Package #2, where the focus is on improvement of food and nutrition security at the household level, a broad nutrition awareness campaign is used, but the activities at the community level are limited to community-sensitization meetings and one-off cooking demonstrations on how to prepare OFSP for young children and how to incorporate this food household diets (Fig. 17.11). With seven components, this approach succeeds in promoting adoption of OFSP and limited amounts of OFSP into the young child diet. The level of impact on young children’s vitamin A levels is less than we see in Innovation Package #1 due to the lack of more intensive community-based nutrition training. The focus of many of these efforts is to strengthen food security at the household level, especially in respond to climate change and/or emergencies such as drought or flood.

Fig. 17.11

Demonstration of how to incorporate OFSP into a range of existing dishes in Tigray, Ethiopia. (Credit: F. Asfaw/CIP)

OFSP Innovation Package #3 is the most complex with 11 components and focuses on building a value chain for using OFSP in processed form to promote diversified use among urban consumers and provide a source of nutritious food and incomes for rural farming households. This package has taken 4–5 years to implement, compared to 2–3 years for Package #2, and 3–4 years for Package #1.

In Package #3, the nutrition awareness component is part of a marketing and demand creation campaign with an emphasized focus on building demand among urban consumers (Fig. 17.12). Two other core innovations are (1) the need to develop an economically viable product that uses the BV as a major ingredient and is well-liked by target consumers and (2) testing products to ensure they have retained enough beta-carotene to be marketed as a good source of vitamin A (which requires the presence of high-quality laboratory services). Additional training is required for market-oriented farmers to obtain sufficient skills to consistently provide quality roots to the processors in sufficient quantities. Associated with the development of such value chains is the development of more standardized systems for monitoring the quality of the seed provided to growers, which requires engagement with government regulatory authorities. With commercialization of the roots, the willingness of farmers to invest in more expensive and higher-quality planting material increases along with the desire for that quality to be guaranteed. To date, scaling efforts for OFSP Package #3 have been concentrated in Kenya, Malawi, and Rwanda, building on proof-of-concept projects using OFSP purée in Kenya and Rwanda.

Fig. 17.12

Entrepreneur Hassana is promoting her Rahama vitamin A gari at a nutritious food fair in Nigeria in 2019. (Credit: HarvestPlus)

One critical aspect insufficiently highlighted in the SR framework by Sartas et al. (2020) is the need to be aware of gender roles and power dynamics around crop production and sale and to design packages that are aware of potential differential impacts of innovation packages on women and men. Agricultural innovations must consider the different roles that men and women take in the adoption process – be it accessing seed, crop production, marketing, processing, or household consumption. Asare-Marfo et al. (2019) systematically consider the various factors to be considered in understanding gender differences along the impact pathway, which influence the success of BVs as an innovation, but do not focus on RT&B crops. They note that men and women may receive their information through different channels or sources, and often men have more access to extension and other services. Moreover, if a BV is bringing a higher price, men may be more inclined than women to sell rather than consume the biofortified food, a result that would have nutritional implications for the household.

Gender dynamics, of course, are context-specific, requiring adjustments by and within countries to develop effective innovation packages. For example, in East Africa male control of labor and production is typically higher for potato and banana, as they are considered cash crops, compared to sweetpotato and cassava, for which home consumption dominates (Okonya et al. 2019) (Fig. 17.13). Women participating in a commercialized OFSP value chain in Rwanda required more training sessions then men to meet quality requirements (Sindi and Low 2015). Particular attention is needed as commercialization of BVs increases to ensure women are not excluded from the benefits, nor are the nutritional goals of BV introduction unduly compromised. Monitoring is requisite. To avoid repetition, we have captured this need for almost every component through labeling the innovation package as gender-responsive.

Fig. 17.13

Men dominate the potato wholesaling in Kenya, reminding us of the need to consider gender appropriately in relation to innovation packages. (Credit: CIP)

5 Assessment of Scaling Readiness and Level of Use According to the Scaling Readiness Framework

Measurement of readiness and use levels reflects the status of biofortification breeding progress, the strategies used to scale, and available resources for different RT&B programs. The measurement of innovation use is more complex than readiness, due to the difficulty in drawing clear lines between the defined categories of actors and the extent of use, both of which vary widely by location. Sartas et al. (2020) distinguishes between:

• 1. The intervention team (typically a research organization initiating the innovation)

• 2. Effective partners (those collaborating directly with the intervention team)

• 3. Innovation network stakeholders (who influence the R4D intervention, but are not involved directly in its testing)

• 4. Other stakeholders in the innovation system (defined as other R4D teams working on similar innovations)

• 5. Stakeholders or beneficiaries in the livelihood system (who were not linked directly to the R4D innovation development)

For example, CIP, an international research organization specialized in potato and sweetpotato research, and HarvestPlus, a program (led by the International Food Policy Research Institute) dedicated to developing and promoting biofortified staples, at times have been on the same intervention team, while in other projects they have served as effective partners or innovation network stakeholders, depending on the innovation package and country. The Alliance of Bioversity International and CIAT has led the VAB effort. Only OFSP and VAC have received major donor support for scaling their BV efforts.

The assessment for each crop is summarized below. For more details, the development and scaling of OFSP have been described in Low et al. (2017) and Low and Thiele (2020). HarvestPlus’ experience in scaling VAC in Nigeria and OFSP in Uganda has recently been described in Foley et al. (2021). Ilona et al. (2017) highlights key aspects of the first phase of the VAC scaling process. The pilot experience with VAB in East Africa is explored in Fongar et al. (2020).

As shown in Table 17.3 (for OFSP innovation packages), out of a maximum possible score of 81, the Food and Nutrition Security and the Improved Nutrition Packages scored 56, and the Improved Income Package scored 18. For VAC, the approach focused on Improved Nutrition and Food Security Package and scored 36, while the Income Package for processed VAC products earned 30 points (Table 17.4). As the lowest score found in any component drives the overall SR score, VAB SR rated only 2 points (Table 17.5), which reflects its pilot level and resource limitations to date (Fig. 17.14).

Fig. 17.14

Vitamin A banana scaling efforts can learn from the OFSP and VAC experiences. (Credit: A. Simbare/Alliance Bioversity-CIAT)

Given that OFSP was the first BV crop to achieve breeding targets, considerable investment was made in delivery system research using OFSP as a model biofortified crop (Low and Thiele 2020). This work produced an excellent evidence base for the improved nutrition outcomes and food and nutrition security packages. Open access investment and implementation guides (Stathers et al. 2015a, b) are available on the Sweetpotato Knowledge Portal (www.sweetpotatoknowledge.org) and provide detailed instructions on how to design, set up, and implement OFSP-focused nutrition and food security interventions. In addition, 13 modules for a Training of Trainers (ToT) course entitled Everything you ever wanted to know about sweetpotato (Stathers et al. 2012), each with activities addressing gender, are available on the Portal in 5 major languages.

As a strategy for scaling OFSP innovation packages by non-research organizations, while assuring that such organizations have access to the latest research knowledge, CIP launched the Sweetpotato for Profit and Health Initiative (SPHI) in 2009 with the goal of reaching 10 million households in 16 SSA countries by 2020 with improved varieties of sweetpotato and promoting their diversified use (Low 2011). During the 10-year period, NGOs were effective partners in proof-of-concept delivery projects initially but then raised independent funding and integrated OFSP varieties into their own programs, which often had many elements of the innovation packages described above, but in some cases could be entirely different – for example, the enhanced homestead garden program led by Helen Keller International (Haselow et al. 2016). Partners in the SPHI submitted annual updates on the number of beneficiary households reached directly (as program participants) or indirectly (spillover spread of varieties). By 2019, Fig. 17.15 clearly shows that the extent of scaling (use) varied enormously by country, reflecting differences in how and when adapted BVs were developed and released, and the levels of government interest and donor country prioritization. Hence, only eight of the 16 targeted SPHI countries had reached “scaling” levels. Two of these countries had major breeding programs (Mozambique and Uganda) to accelerate development and promotion of superior BVs.

Fig. 17.15

Number of households reached by country from June 2010 to June 2019 under the Sweetpotato for Profit and Health Initiative. (Source: Okello et al. 2019)

VAC focused its breeding efforts in Nigeria and DR Congo, due to the dominance of cassava as a major staple in the diets in these countries. Scaling efforts have focused on Nigeria, a country that is home to 18% of the entire population of sub-Saharan Africa (Table 17.4). The innovation packages for VAC are more complex than those presented for OFSP, reflecting a concerted effort to develop commercialized cassava “seed” production and a diverse set of interventions to promote nutrition awareness and stimulate demand for VAC versions of a diverse array of processed products common in Nigeria. On the seed front, HarvestPlus developed a distribution system using labeled packaging with 50 stems (planting material) that were distributed for free but with recipient households agreeing to “pay back” by providing the 50 VAC stems to two households in the following season. Since 2015, emphasis has been placed on developing links between growers and stem multipliers with the goal of shifting to more commercialized seed and marketing systems. By 2018, 8% of VAC stems were being purchased (Foley et al. 2021). On demand creation, extensive use of radio, television, and social and print media and the establishment of an annual nutritious food fairs with a broad range of policy makers and celebrities helped promote VAC products as preferred choices over non-VAC options and facilitated the establishment of roadside VAC selling points to generate interest. As a result, by 2018, 50,000 ha were under VAC cultivation (Foley et al. 2021) (Fig. 17.16).

Fig. 17.16

Farmers in Nigeria display vitamin A cassava. (Credit: HarvestPlus)

In the assessment tables (Tables 17.3–17.5), we can see the following scores for BV readiness: 9 for OFSP, 6 for VAC, and 4 for VAB. Breeding is a continual process, but a 9 indicates that appropriate varieties are available that meet the target beta-carotene levels, have been adapted to local growing conditions, meet adult consumer preferences, and have documented evidence of bioavailability. Some OFSP and VAC varieties have an additional advantage of being higher-yielding than dominant varieties on the market (Low and Thiele 2020; Foley et al. 2021), which helps drive uptake. Bioaccessibility in VAB has been confirmed, but resources to confirm bioavailability have not yet been raised.

Scores vary by and within countries, but the value of SR is in its ability to pinpoint where bottlenecks may be occurring. The challenges facing growers’ access to BVs of OFSP, VAC, and VAB are no different from access issues for non-BV crops. Because RT&B planting material is easily retained, reused, and shared, private sector seed companies have not been interested to invest in these RT&B systems. CIP, HarvestPlus, and partners invested in developing networks of trained multipliers to provide greater access for growers to quality seed (Fig. 17.17). Initially, these systems were subsidized by project funding, providing free or subsidized material to growers to achieve desired nutrition and/or food security outcomes. The ability for these multiplication systems to evolve into more self-sustaining commercial entities has been highly dependent on the development of markets for BVs in fresh and/or processed form. Building on a long history of cassava agro-processing in Nigeria, VAC-processed product development has been supported among both small-scale and larger processors, with use scores reaching 7. In contrast, since most sweetpotato roots are consumed boiled or steamed, processed product development is a new phenomenon; therefore its use level is 4 in the indicated countries, showing that support is still needed from the original research for development partners. The SPHI annually monitored whether OFSP vine multipliers continued to produce planting material during and post-project. In 2019, 503 of 741 trained multipliers contacted in 11 countries were selling vines (Makokha et al. 2019). Recognizing the important of root markets to drive willingness-to-pay for quality planting materials, efforts are focused on validating vine-root enterprises as an integral part of the improved incomes package (readiness at 6; use at 3).

Fig. 17.17

A trained OFSP multiplier harvesting planting material in Mwanza, Tanzania. (Credit: K. Ogero/CIP)

Concurrent with processed product development and its commercialization, an adoption of standards and services to validate that standardization was needed. In Kenya, the Food Analysis and Nutrition Evaluation Laboratory (FANEL) was established in 2014 as a reference service for vitamin A and other nutrient assessments, including iron and zinc. This lab facilitates labeling of biofortified products to assure consumers about vitamin A content (Muzhingi et al. 2019). For VAC, standards and guides for nutrient retention have been key, and these efforts are being strengthened through investment in tools that can more rapidly determine whether a product meets quality standards (Foley et al. 2021). Technical support in the use of such protocols and guidelines is required for validation and uptake by regulatory bodies.

On the advocacy and policy side, biofortification has been at the forefront for developing demand creation strategies and for understanding how to train and support local and regional influencers as policy advocates. Consequently, there has been widespread integration of biofortified crops as part of nutrition and agricultural policies in 24 SSA countries (Covic et al. 2017). This kind of integration into national and regional policies also facilitates enhanced government and outside donor investment in government-prioritized interventions. Readiness scores for OFSP and VAC in this area are 8 or 9 and the use of different approaches varies from 4 to 9, depending on the outcome model and country context. As VAB promotion is more recent, recognition of its potential by both governments and donors is lagging (Table 17.5), but VAB will be able to draw on the groundwork and lessons learned by from the OFSP and VAC experience.

6 Reaching Scale in SSA: Lessons Learned

The SR assessment provides a framework for reflecting critically on the scaling process, helping to identify bottlenecks and essential factors to support scaling. As noted by Fongar et al. (2020), “lessons for scaling regionwide adoption of VABs can be drawn from the introduction and scaling of OFSPs in SSA.” The same holds true for IP, although in the latter case since iron is not a visible trait, the high-iron bean scaling effort in Rwanda is probably more relevant (Foley et al. 2021).

In their review of the 25-year OFSP development and implementation experience, Low and Thiele (2020) examine the requisite technical, organizational, leadership, and enabling environment associated with each phase examined. In this section, we will review major lessons learned concerning VAC and OFSP.

6.1 Technical Considerations

BVs must be agronomically competitive with dominant non-BVs and meet the taste and key quality preferences of adult consumers to achieve widespread uptake. Several cycles of breeding were required in Uganda, for instance, to produce OFSP varieties that had the desired texture. Meeting the biofortification target level is desirable for uptake but not requisite. In Nigeria, VAC varieties with <12 μg g-1 of beta-carotene have been accepted and widely cultivated by farmers. Thus, the platform is already in place for incorporating varieties with the desired levels of beta-carotene above 15 μg g-1 once released. However, caution is warranted in serving size recommendations and labeling of processed products to avoid unsubstantiated claims that may lead to a violation of trust. The establishment of protocols and laboratory services to measure nutrient retention has been a complementary component of packages focused on commercial product development. To date, research support to private sector enterprises has encouraged testing and labeling, given that the regulatory structure for managing biofortified products is still nascent.

Taste and consumer preferences vary by target groups and locations, so investment in acceptability studies among different consumer segments and across multiple locations is warranted. For example, VAB researchers found significant variation in the ranking of the same varieties in different communities within the same country (Ekesa et al. 2017). The importance of quality traits that capture sensory characteristics which vary by end use and postharvest considerations, such as storability, has been underemphasized in RT&B public sector breeding programs to date, but are the focus of growing interest due to their critical importance in driving adoption (Thiele et al. 2021).

In comparison to grain crops, RT&B seed systems have tended to be more informal and less commercialized. A large share of smallholder farmers retain their own planting material from year to year, only seeking new material if there is significant yield decline, loss due to drought or theft, or a new variety demanded by the market. Farmer-to-farmer sharing of seed is common. This context required significant investment to set up innovative systems for delivering high-quality planting material of biofortified varieties while also convincing farmers of the yield value in using quality seed (Fig. 17.18). For scaling, it is requisite that seed system barriers be overcome to ensure varieties are available that meet consumer demands and that quality seed is accessible to more farmers at planting time. Since seed and root supply is critical for scaling, larger multipliers and growers had to be recruited to complement smallholder farmers.

Fig. 17.18

Distribution of banana plantlets to members of farmers’ association in Burundi. (Credit: A. Simbare/Alliance Bioversity-CIAT)

The experiences of OFSP and VAC demonstrate that is possible to develop sustainable enterprises which bring the vegetatively propagated seed closer to farmers through networks of decentralized multipliers. These small- and medium-sized businesses become critical for meeting RT&B seed demand, even more so during the 2020 pandemic. Work is still underway to improve linkages between decentralized multipliers and early generation seed producers, to ensure timely renewal of quality multiplication stock. The use of digital tools and other innovations to help policy makers regulate and practitioners to monitor the seed system are included in the RTB Seed System Toolbox (https://www.rtb.cgiar.org/seed-system-toolbox), which is currently being evaluated in several SSA countries. Concerning VAC in Nigeria, development of the market for seed was done concurrently with promotion of VAC-processed products. To support private sector participation, clear business cases should be developed and tested, with the return on investment (ROI) being higher than bank interest rates.

SR assessments pinpoint the seed system as a key bottleneck. Few private sector companies in SSA are engaged in early generation seed (EGS) production (tissue culture, pre-basic seed production), and CGIAR emphasis has focused on strengthening public sector national program management capacity in this regard. A detailed study of one private company that has invested in EGS and basic seed production found that such a business requires significant upfront financial support due to high initial investment costs. The payback period required for such an investment is 3–7 years, with an average annual return of 34–70% (Rajendran and McEwan 2019). Having open-field basic seed production linked to EGS did increase economies of scale for this company.

Using disease-free planting material can have significant yield benefits, and there has been increasing interest to develop a regulatory framework for certifying the quality of RT&B planting material. In SSA, potato is the only root and tuber crop where several countries have seed certification schemes, reflecting its highly commercialized nature. Even so, less than 5% of potato seed sold outside of South Africa is certified. Such schemes typically require public sector support and investment. Cassava and sweetpotato programs have focused on developing less costly quality declared seed protocols and decentralized inspection systems. The introduction of greater regulation of seed quality correlates highly with increased commercialization of the crop. The use scores for these types of regulatory systems are among the lowest among the innovation package components due to the need for end users to be convinced of the value.

To lower risk for private sector participation, investment in demand creation campaigns and provision of technical support for production and utilization of BVs by the research for development partners has been central to jumpstarting private sector engagement. HarvestPlus has used existing platforms in Nigeria, like the Nutritious Food Fair/Alliance, Smart-Mother, and NutriQuiz to reach millions of Nigerians. Doing so increased the use scores of VAC innovation packages.

Learning how to address gender has been critical for scaling packages. For nutrition outcomes, recognizing that men have primary decision-making authority on what crops to plant, what foods are purchased, and how different foods are allocated among household members has led to the development of community-based nutrition interventions that integrate men, women, and local leaders to address household dietary quality and young child care practices (Girard et al. 2021) (Fig. 17.19). Regarding income, efforts have been made to ensure that women are not sidelined when developing or improving market interventions. This effect is achieved by setting explicit targets for female participation and addressing specific service and capacity needs of women who may be underserved due to longstanding social and/or economic barriers to participation. As expected, the impact of biofortified crops has been greatest for women and children in nutrition-focused interventions and on poorer rural households for broader household food security and dietary diversity (Bouis et al. 2020; de Brauw et al. 2018).

Fig. 17.19

Encouraging men to feed their young children is often part of behavioral change programs for OFSP. (Credit: CIP)

6.2 Organizational and Leadership Considerations

Given the complexity of the science and the need for sustained investment to achieve impact at scale, organizations such as HarvestPlus and the International Potato Center have been essential for building the evidence base for nutrition-sensitive agricultural interventions and expansion at scale (Bouis and Saltzman 2017; Bouis et al. 2020; Low and Thiele 2020). These organizations have also developed and managed cross-country, cross-project, and cross-partner monitoring systems to capture progress. This work has enabled groups to obtain timely feedback on varietal and package performance and to respond to scientific and policy queries with evidence.

As government and NGO partners have become increasingly involved, it is clear that the food and nutrition innovation package – the simplest of the three – is the easiest to adapt and use at scale. In this context, BVs of roots and tubers are often a part of a much broader package of crop and management practice interventions. Expanding partnerships with the World Food Program and international NGOs should continue and be strengthened to make BVs available for food assistance and resilience programming in fragile environments where nutritionally vulnerable populations are the norm.

The scalability of the improved nutrition innovation package is most likely in countries where there is strong support for community-based health workers by the government (e.g., Ethiopia, Ghana, and Malawi). Lacking that support, the higher cost of this approach compared to focusing on food and nutrition security at the household level means that a more cost-effective but longer-term solution may be to integrate nutrition education into primary and secondary school curricula and antenatal and postnatal care counseling and existing school feeding programs (Fig. 17.20).

Fig. 17.20

A girl in preschool in Nigeria enjoys custard made from vitamin A cassava. (Credit: HarvestPlus)

Certainly, innovation packages focused on income enhancement are the most attractive to private sector partners. Given that many of the processing partners are small- and medium-scale enterprises, the need for significant technical support should not be underestimated, especially in developing a value proposition for investment. There is an increasing effort to focus on youth opportunities for employment associated with these efforts. While many successful examples of profitable, commercially oriented value chains exist, action research is needed to design and test ways to adapt and scale such programs to widen the scope of impact.

6.3 The Enabling Environment

For any innovation to take root, flourish, and scale, an enabling environment is needed for sustainability. Bouis and Saltzman (2017) have identified building blocks necessary for biofortified crops to scale:

• 1. Globally, biofortification must be integrated into global standards and regulatory guidelines such as Codex Alimentarius¹. As multilateral institutions (World Bank, African Development Bank, World Food Programme, World Health Organization) integrate biofortified crops into their policies and programming, governmental and nongovernmental organizations (NGOs) can more easily include them in national policies, plans, and programs.

• 2. Within Africa, the endorsement of the African Union and the Regional Economic Communities can facilitate and act as an encouragement for individual countries to include biofortification as a nutrition-sensitive approach. HarvestPlus and CIP have jointly and individually advocated for biofortification to be included in regional and national government policies.

• 3. Translating policy into action involves incorporating biofortified crops into programs and plans that are then implemented through governmental and nongovernmental bodies (Covic et al. 2017). Both organizations have funded efforts to develop and test strategies to identify, recruit, and train advocates at national and regional levels.

NGOs are important because they are crucial partners for delivering innovations to more vulnerable households. To create sustainable markets, private sector participation is essential – from seed to food delivery. Private sector seed companies have the power to shorten time to market of biofortified seed varieties, although for RT&B crops this may be more problematic. Nonetheless, private sector involvement in processing is critical and facilitates the inclusion of biofortified crops as ingredients in food product value chains. As noted above, demand for the final product is critical to drive willingness-to-pay for inputs such as quality seed.

Initiatives like SPHI that bring donors and multi-sectoral stakeholders from different countries enhance the speed of innovation spread and stakeholder buy-in. Training programs that emphasize agriculture-nutrition-marketing approaches and efforts to produce qualified extension personnel are critical for within-country expansion. While integrating biofortification within national policies of agriculture, food security, and nutrition may constitute “readiness,” encouraging governments and NGOs to allocate their own funds for BV dissemination is essential for achieving use at scale. Certainly, our scaling experience has shown that countries with better agricultural extension systems (Ethiopia, Kenya, Malawi) have greater capacity and more willingness to engage in diffusing new innovations than those countries where public sector extension has been downgraded (Uganda, Nigeria). As the number and type of partners grow, lead organizations play more of a facilitation and knowledge role and provide essential monitoring of progress. For example, we have seen some commercially oriented firms make unsubstantiated health claims. Scientists and advocates need to be proactive in setting the record straight and developing outreach strategies that will prevent such claims in the first place.

Sometimes luck plays a part. Low and Thiele (2020) noted that a major OFSP-based study that demonstrated the nutritional impact of the integrated agriculture-nutrition approach coincided with a shift in the institutional environment that placed agriculture and nutrition at the forefront of the development agenda. This coincidental happenstance created an inflection point that led to increased investment in research and diffusion of biofortified crops.

7 Final Considerations

RT&B crops have always been among the most affordable sources of calories for rural and urban poor. Biofortified RT&Bs can serve as major affordable sources of key micronutrients in an emerging and more resilient food system in SSA. RTB crops often have shorter supply chains and are less expensive than grains; hence, market disruptions are less likely to affect availability and access, an advantage made more evident during the 2020 pandemic.

As scaling efforts expand, managing the perishability and seasonality of RT&B crops at larger scales will require greater investment in physical market chain infrastructure, storage, information systems, and enterprise development. These objectives can be achieved by working across multiple nutritious commodities to strengthen informal and formal food market systems. The value added from RT&B BVs will be to secure affordable nutrition for low-income consumers, while also providing economically attractive and nutritious ingredients in food processing and new market opportunities for producers. Stronger smallholder market participation will underpin the ability to develop commercial input supply chains for RT&B crops in SSA.

While scaling efforts utilize existing varieties, breeding must be a continuous effort, particularly in the context of climate change where new, improved materials will be essential for assuring a nutritious food supply. A major feature of climate change is the rapidly increasing carbon dioxide (CO2) levels, predicted to rise from 400 ppm to over 550 ppm by 2050. With increasing CO2 levels, sweetpotato, banana, and cassava yields are expected to increase (Jarvis et al. 2012; Varma and Bebber 2019), but that increase will be channeled into carbohydrate accumulation. Potato is sensitive to temperature and drought and thus likely to see decreased yields (Fleisher et al. 2017). Hence, R&TB crops, along with wheat and rice, are expected to show significant declines in nutrient density, including many nutrients critical to human health such as zinc, iron, and protein (Smith et al. 2018). Nelson et al. (2018) predict that the “greatest food security challenge in 2050 will be providing nutritious diets rather than adequate calories.” Clearly, given the heavy dependence on staple foods by the poor, increased commitment to breeding for enhanced micronutrient and protein content is warranted.

All R&TB varieties released to date were developed through a targeted approach with a focus on specific crop/country combinations and tightly linked to key traits that trigger adoption. Banana is one R&TB crop where major breeding investments are using transgenic approaches to tackle disease resistance and vitamin A enhancement (Amah et al. 2019). In the future, prospects are excellent for genetic engineering to integrate full target increments in micronutrient content for several nutrients in one go, not only in next wave but also in existing commercial varieties. This potential would shortcut mainstreaming time enormously and accelerate the reach and impact of the intervention (Van Der Straeten et al. 2020). However, the regulatory environment and social acceptance of transgenic materials must improve for the value of such innovative approaches to be realized.

In some contexts, R&TB crops have an image problem to address, which reflects a lack of understanding of their role in poor people’s diets in low-income countries. In their analysis of healthy and sustainable diets, the EAT Lancet Commission recommended low daily intakes of potato and cassava as staples relative to grains, in spite of the fact that these crops have much lower environmental impacts. Sweetpotatoes and Musa spp. were not specifically mentioned. Given the Western orientation of the article, sweetpotato was probably classified as an orange and red vegetable and Musa spp. designated as fruits (Willett et al. 2019). The highly negative image of potato as a junk food in the Western diet is associated with its high glycemic index and its frequent consumption as a fried product. Most potato in SSA, however, is consumed boiled.  Moreover, insufficient attention has been paid to enhancing the use of micronutrient-rich leaves of cassava and sweetpotato for human consumption.

Clearly, the lessons learned from the OFSP and VAC scaling experiences can inform VAB and IP development and dissemination efforts and avoid the tendency to “reinvent the wheel.” RT&B crops are well-positioned to move forward in the context of emergency recovery and gender-responsive food system transformation for more climate-resilient and nutritious foods. The SR Tool has pinpointed the degree to which different components of OFSP and VAC innovation packages were validated through evidence-based assessment. The innovation packages can be easily adapted for different country contexts, and the SR Tool is recommended for use in monitoring RTB scaling efforts over time to pinpoint bottlenecks.

Inclusion of biofortification by the Scaling Up Nutrition country programs and the potential recognition of biofortification by the African Union are two examples of policy engagement that are needed to keep biofortification and nutrition at the forefront of food policy and investment planning.