Market-driven transitions in the vegetable seed sector in sub-Saharan Africa

seed types, especially hybrids. In this trajectory, different companies take on different roles based on specialization in seed system functions: variety development, seed production, seed dissemination, and seed use. The coexistence of and collaboration between different (private) actors in the vegetable seed sector contribute to plurality and interaction in line with an integrated approach to seed sector development. However, it is not a static condition as company roles evolve with expanding business models in terms of seed system functions and market segments. SIGNIFICANCE: A general objective of (national) seed policies is to increase farmers' access and choice in terms of quality seed of improved varieties. Seed sector development interventions can enhance inclusivity by focusing on viable and innovative business models for niche markets in terms of farming systems and crop types.


CONTEXT:
Quality vegetable seed has the potential to significantly impact nutrition security in sub-Saharan Africa, as the region has the world's lowest per capita production and consumption of vegetables.Moreover, seed companies might have an important role to play, as in Asia, vegetable production and consumption increased rapidly following the expansion of the private seed sector.However, market-driven seed sector development remains contentious, with some celebrating technological advancements and others raising concerns.
OBJECTIVE: This paper contributes to seed systems literature by focusing on the role of vegetable crops and diversity within the private sector.It explores the heterogeneous character of the private sector by studying how different business models of leading vegetable seed companies jointly contribute to sector development in sub-Saharan Africa.METHODOLOGY: Eighteen in-depth interviews were conducted with leading vegetable seed companies operating in the region.Qualitative tools were selected to translate individual company data into general findings; while thematic analysis was used to pinpoint a private sector perspective and ideal-type analysis was used to construct business model typologies.

RESULTS AND CONCLUSIONS:
The results show that seed companies collectively view seed sector development as a linear trajectory involving public and private investments to enable farmers to adopt increasingly advanced

Introduction
Seed companies play a critical role in providing farmers with access to quality seed of improved varieties, which is vital for achieving Sustainable Development Goal (SDG) 2: Zero Hunger.Vegetables are a crucial component of healthy diets and often represent an important income source for smallholder farmers (Schreinemachers et al., 2017).In Asia, the private sector's combined approach of breeding, distribution, demonstration, and capacity building triggered a major increase in the use of quality vegetable seed as well as vegetable production and consumption levels (Schreinemachers et al., 2021;Scoones and Thompson, 2011).This trajectory projects an important role for seed companies in sub-Saharan Africa (SSA), as the region has the world's lowest vegetable production and consumption levels, and development of the private seed sector has moved slowly (Schreinemachers et al., 2021;Steenhuijsen Piters et al., 2021).At the same time, the role of seed companies in achieving global nutrition security has grown controversial.While proponents associate seed companies with technological advancement, opponents tend to associate them with market consolidation and farmer dependency (Béné et al., 2019;Clapp, 2020;Westengen et al., 2023).Considering the urgent need to realize SDG 2, there is an equally urgent need to assess how business models of leading vegetable seed companies are contributing to development trajectories in SSA.
Large amounts of development funding have been spent to drive market-driven seed sector development (Scoones and Thompson, 2011;Westengen et al., 2023).The Alliance for a Green Revolution in Africa had an approximate budget of USD 1 billion between 2007 and 2020, focusing on staple crops (Wise, 2020).The Dutch government spent approximately EUR 214 million on seed sector development between 2018 and 2022, focusing on vegetables and potato amongst other crops (Wageningen Centre for Development Innovation (WCDI), 2023).However, the exact impact of these interventions remains unclear.Some quantitative studies show positive results in terms of the adoption of improved varieties and subsequent livelihood outcomes in a specific context (Deutschmann et al., 2021;Ruzzante et al., 2021;Takahashi et al., 2019).Similarly, qualitative research underlines that the level and impact of the adoption of improved varieties depend on contextual factors (Almekinders et al., 2019;Kilwinger, 2022).There remains an absence of scientific data (Nabuuma et al., 2022), and for vegetables there is less information than on staples, as the focus of academics, policymakers and development practitioners remains on the latter, especially maize (Louwaars and de Boef, 2012;Louwaars et al., 2013;Nabuuma et al., 2022).
The Access to Seeds Index, published in 2016, 2019, and 2021, "measures and compares the efforts of the world's leading seed companies to enhance the productivity of smallholder farmers" (Access to Seeds Foundation, 2019; Misal et al., 2021;Verhagen et al., 2016).Through benchmarking and publicizing the efforts of companies, the Index seeks to incentivize companies to do better.Most seed companies obtain low scores and the conclusion drawn by the Access to Seeds Index team is that the performance of companies is "concerning" (Misal and Ingabire, 2022).An alternative interpretation could be that while the smallholder segment is commercially interesting for some companies, it does not represent a "sufficiently profitable market" for others (Beumer and Stemerding, 2021).The Index represents the first attempt to increase transparency in the seed sector by ranking business models and promoting best practices.However, it focuses exclusively on smallholder farmers without defining this concept and does not consider the different ways in which companies can contribute to seed sector development, or whether companies use external (public) funds to implement certain activities (World Benchmarking Alliance (WBA), 2021).
Our paper seeks to contribute to the seed systems literature and address this evidence gap by focusing on vegetable seed systems and diversity within the private sector.Specifically, we focus on the role of leading vegetable seed companies in seed sector development in SSA because vegetable seed companies are frontrunners in terms of innovation and farmer outreach.It explores the heterogeneous character of the private sector by studying how different business models impact seed sector development in SSA through 18 in-depth interviews with the (regional) commercial directors of companies operating in the region, using qualitative tools to translate individual company data into general findings.The results indicate that seed companies collectively view sector development as a linear trajectory in which professionalizing farming systems and produce markets are associated with rising standards for seed quality and genetics, and in which companies take on different roles specializing in seed system functions.In our discussion and conclusion, we reflect on the approaches of leading vegetable seed companies and evaluate how policies might enhance the positive impact of market-driven seed sector development.

Quality seed
Quality seed is a subjective term for which farmers, seed companies and governments all have their own definition.A distinction should be made here between legal and farmer perceptions of quality.In formal systems, quality standards are defined by law and controlled via seed certification and testing schemes (Louwaars and de Boef, 2012).Additionally, every seed company can have its own standards that move beyond the regulatory minimum.Farmers have individual preferences and look for seed which matches their farming system, dietary preferences and/or market demands.Almekinders and Louwaars (1999) list four aspects of seed quality: genetic, physiological, sanitary, and analytical quality.Genetic quality refers to varietal adaptation, identity, and purity; physiological quality refers to seed germination and vigour; sanitary quality refers to the absence of seed-transmitted disease, and analytical quality refers to the percentage of 'good seed' as opposed to inert matter or 'other' seeds.Genetic quality can be improved through breeding, while physiological quality can be improved through multiplication and conditioning techniques (Kilwinger, 2022).Quality levels are often linked to the origins of seed, referring to the conditions under which a variety was generated and seed was produced.Indeed, quality differences exist between formally-produced and farm-saved seed, but these may not always lead to significant differences in crop performance in prevailing farming systems (Almekinders and Louwaars, 1999).Moreover, other factors such as the availability and cost of seed may also play a decisive role for farmers (Louwaars and de Boef, 2012).
In terms of vegetable seed type, it is possible to distinguish between four categories, based on seed source and variety: farm-saved seed, open-pollinated variety (OPV) seed, standard hybrid seed and advanced hybrid seed.All types could be considered quality seed when meeting the standards of a government, company, or farmer.The first type is produced by farmers themselves and referred to as 'farm-saved seed'.The varieties may be landraces, also called 'traditional varieties'; 'farmers' new varieties', resulting from farmer selection; or reproduced modern varieties (Salazar et al., 2007).Farm-saved seed becomes available to farmers by saving on-farm, through local exchanges or through local produce markets (Lipper et al., 2009).The three remaining types are obtained via formal channels like seed shops or distribution by the government or NGOs.We use the term OPV to refer to purchased seed of a defined variety that is reproduced through open pollination.These varieties may exist for a long time or have been recently bred; they may be protected by plant variety protection, or be unprotected and part of the public domain.OPVs of self-pollinating crops like tomato, beans and lettuce are genetically stable and suitable for re-use, while OPVs of cross-fertilizing crops like onion, squash and melons require more care to maintain varietal identity and purity when farmers save seed for the next season.Hybrids (also called F1-hybrids) are the product of crossing two distinct parent lines combining important traits (ter Steeg et al., 2022).Generally, hybrids are more uniform than OPVs in crossfertilizing crops.However, hybrids are genetically unstable when reproduced, which means that farmers should not save seed if they want to maintain varietal qualities.We distinguish between two types of hybrids: 'standard hybrids' which are improved varieties that combine more useful traits and are bred for a higher yield potential, versus 'advanced hybrids' which are developed for high-end farm and market systems.Advanced hybrids are expensive and require more horticultural skills of farmers to gain a return on their investment.Practices such as using seedling trays, mulching, or trellising can increase germination rates, yields and product quality substantially.In developed markets, vegetable seed companies almost exclusively sell advanced hybrids except for crops for which hybrid seed cannot be produced profitably such as lettuce and beans.In seed markets in low and middle-income countries in SSA, companies tend to have OPVs, standard hybrids and advanced hybrids in their product portfolios.

Seed systems
Seed systems represent the set of activities affecting access to and use of seeds (Tripp, 1997).A well-functioning seed system provides "sufficient access to adequate quantities of good quality seed and planting materials of preferred crop varieties at all times" (FAO, 2016).Traditionally, a distinction has been made between formal and informal seed systems (Louwaars, 2007;Louwaars and de Boef, 2012).Informal seed systems are also referred to as farmer or local seed systems.In informal systems, farmers save seeds themselves or obtain seeds via their (social) network or markets based on processes of exchange, gifts, or payment (Sperling and Almekinders, 2023).Variety development, seed production, and dissemination are integrated in the farming system and farmer communities.In formal seed systems, farmers buy seeds (or seedlings), which are produced and supplied through a specialized and regulated value chain (Almekinders and Louwaars, 1999).In the formal system, farmers may also receive seeds 'for free' via development or government distribution programmes.Nowadays, seed systems are usually placed along a spectrum ranging from informal to formal, with several intermediary forms (Westengen et al., 2023).
Some scholars prefer to focus on seed system functions instead, looking at variety development, seed production, seed dissemination and seed use (Fig. 1) (Christinck et al., 2018;Westengen et al., 2023).
Seed system functions are similar in informal and formal systems, but the actors and techniques involved, and agents with the power to make decisions, are different.In informal systems farmers will take on more (if not all) seed system functions, while they are often considered to be 'seed users' in the formal system.Seed system functions are shaped by and operate in the legal framework, sociocultural system and agroecological system (Borman et al., 2022;Christinck et al., 2018;Westengen et al., 2023).The legal framework may affect seed systems intentionally, regulating varieties and seed quality in the formal systems, or unintentionally, affecting informal or intermediate system functions (Louwaars et al., 2013).Seed systems are also embedded in sociocultural systems, notably regarding gender roles in selection, storing and purchasing of seeds.Finally, seeds must fit in the agroecological system which define farming conditions.

Integrated seed sector development
Integrated seed sector development has been defined by Louwaars and de Boef (2012) as the integration of formal and informal seed systems at the technical and institutional levels.The two fundamental principles of an integrated approach to seed sector development are plurality and interaction.Firstly, seed sector development should be looked at in a pluralistic manner.An integrated approach recognizes that no single system, actor, or intervention can meet the diverse needs of farmers.Seed system diversity enhances farmers' ability to access their preferred variety and type of seed (Nabuuma et al., 2020).Individual farmers use different seed systems to obtain seed for different crops as well as the same crop: one tomato farmer may plant farm-saved seed, OPV seed, and advanced hybrid seed in adjacent plots (Sperling and Almekinders, 2023;ter Steeg and Gildemacher, 2023).Secondly, the interaction between formal and informal seed systems strengthens both.It is essential for breeders that genetic material and information on local conditions flow from the informal to the formal system (Almekinders and Louwaars, 1999).It is also clear that varieties and traits which flow from the formal to the informal system can reach more farmers through local dissemination (De Jonge et al., 2022;Schreinemachers et al., 2017).Similarly, methods for seed storage and marketing can flow from the formal sector to improve those used in the informal Fig. 1.The four basic seed system functions embedded in the legal framework, sociocultural and agroecological system (adapted from Christinck et al., 2018).system.

Market-driven seed sector development
The aim of seed companies is to produce and sell quality seed of improved varieties that match the needs of farmers.They often create demand for their products by showcasing varieties on demo-plots and distributing seeds via a network of agrodealers.Moreover, companies may provide extension services alongside standard marketing and sales activities.To facilitate adoption, a 'bundled' or 'multi-component' approach tends to be required that provides farmers with simultaneous access to quality inputs, training, and credit (Deutschmann et al., 2021;Nabuuma et al., 2022).Capacity building or extension services tend to be required because the simultaneous adoption of improved varieties and good agricultural practices is generally needed to generate a return on the investment in quality seed (ter Steeg and Gildemacher, 2023).However, there are difficulties associated with companies' outreach to farmers.Riungu et al. (2021) found that the commercial set-up of demonstrations or field days may inhibit social learning and adoption, while Miehe, 2023 found that some farmers may refrain from investing in seed once they are better informed regarding risks and costs associated with improved varieties.
It should be stressed that globally the public sector is not absent in market-driven seed sector development.When it comes to variety development, breeding and seed research are largely managed by universities and research institutes for most crops.Precompetitive research is supported in many countries through public-private partnerships (Beumer and Stemerding, 2021;Dhillon et al., 2020).The private sector is, however, dominant in vegetable breeding as the public sector tends to focus on major food crops (ter Steeg et al., 2022;Schreinemachers et al., 2017).The World Vegetable Center, with stations in Benin and Tanzania, is an important exception in this respect.Regarding seed production and dissemination, the public sector has key responsibilities in terms of quality assurance and monitoring compliance.In terms of seed use, the public sector commonly (co-)funds development projects, for example to incentivize private actors to provide extension and capacity building services (Scoones and Thompson, 2011); but as marketdriven seed sector development aims at long-term financial sustainability, public funding is usually limited after a kickstart.

Contextual framework 2.5.1. Vegetable crops
Vegetables are often used as exemplary crops for which formal seed systems work (Almekinders et al., 2019;Louwaars and de Boef, 2012;Mausch et al., 2021).Vegetable seed systems differ markedly from those of major food crops such as cereals and pulses where the harvested product is botanically identical to the seed.For vegetables, seed production is a separate activity; the seeds commonly appear after the harvest of the vegetable crop, which requires selected plants to be kept in the field longer (Pandita et al., 2023).Some vegetable crops may not produce seeds due to unsuitable climatic conditions, which means that farmers must buy seed.In addition to the separate seed production process, the small amounts of seed required and high market value of produce probably raises the willingness and ability of farmers to invest in quality vegetable seed (Steenhuijsen Piters et al., 2021).As a result, farmers are generally more willing to purchase seed for vegetable than field crop production.
A distinction can be made between local and global vegetables.Local vegetables are indigenous to or have been naturalized in a particular region and are embedded in the sociocultural system (Towns and Shackleton, 2019).In SSA, local vegetables include amaranth, African eggplant, African kale (collards) and okra.Seed for local vegetables is mostly saved or sourced via the informal sector.Meanwhile, seed for global vegetables is mostly sourced via the formal system.Global vegetables (also called exotic vegetables) like tomato, onion, cabbage, cucumber, pepper, and eggplant, are consumed around the world and often considered 'commercially important' (Towns and Shackleton, 2019).For certain crops like cabbage and onion, seed production in the tropics is challenging because low temperatures and specific day-length regimes are required for optimal flowering and seed set (Motoki et al., 2019;Tesfay et al., 2011).In summary, the informal system is dominant for local vegetables; the formal system is dominant for global vegetables; but many intermediary systems exist.
However, the distinctions between local versus global crops, and informal versus formal seed systems seem to be shifting.A literature review by Ayenan et al. (2021) identifies a private-sector model as the most financially sustainable system to raise seed quality and availability for local vegetables.Whenever the value of harvested products increases thanks to improved logistics and the rise of urban markets, farmers are incentivized to invest in quality seed (ter Steeg and Gildemacher, 2023).The 2021 edition of the Access to Seeds Index showed that 25 out of 67 seed companies include local crops in their portfolio (Misal et al., 2021).Some companies have launched hybrid breeding programmes for local crops like African eggplant (Dinssa et al., 2015).The main determinant seems to be whether a vegetable is a commercial or subsistence crop.
Gender considerations are important throughout, whether carrying out extension activities to improve vegetable cultivation, or marketing quality seeds of improved varieties (Kramer and Trachtman, 2024).This is because vegetable productionlike the general agricultural systemis shaped by gender norms (Brearley and Kramer, 2020).The distinction between commercial and subsistence crops also has a gender dimension.Kramer and Trachtman (2024) describe how home gardens for vegetable production often remain "a women's domain" in SSA, but stress that reinforcement of stereotypes is undesirable, and that local context is especially important, as across SSA gender norms significantly differ so that gender-intentional designs will have different impacts.

Revolution of greens
Vegetable seed companies have had a major impact on seed systems in developed and developing countries.Schreinemachers et al. (2021) describe how the public-driven Green Revolution of the 1960s and 1970s focused on major food crops.They show that in contrast, the 'Revolution of Greens' in Asia in the 1990s was market-driven and led to a tremendous increase in vegetable production and consumption, following regulatory reform under which local and global seed companies realized a large market expansion, investing in the capacity building of farmers and demonstration to promote the adoption of quality inputs and good agricultural practices.Furthermore, they point out that at the beginning of the 1990s vegetable consumption levels were similar in Asia and SSA, but that while levels have greatly increased across Asia, hardly any change can be observed in SSA.Thus, Asia's trajectory suggests that the private seed sector could have an important role to play in SSA.

The vegetable seed sector in sub-Saharan Africa
Seed sector development has moved slowly in SSA: technology adoption remains low while yield gaps generally remain high (Bold et al., 2017;Gaffney et al., 2016;Suri and Udry, 2022).Like Asia, several countries implemented reforms to liberalize the seed sector from the 1980s onwards (Schreinemachers et al., 2021).However, this did not lead to the rise of formal seed systems or large-scale establishment of global and local seed companies in SSA except for hybrid maize (Erenstein and Kassie, 2018).The reforms did lead to the founding of some vegetable seed companies in East and Southern Africa, but less so in West and Central Africa.Local seed companies have mostly focused on seed trade and distribution (Misal and Ingabire, 2022).
Export data can be used as an indicator of formal seed sector development.Increasing European vegetable seed exports to SSA indicate that local and global seed companies are successfully creating demand for their products (Figs. 2 and 3).

Material and methods
This article combines thematic and ideal-type analysis to define a private sector perspective and build an understanding of how leading vegetable seed companies are currently contributing to seed sector development in SSA.The core of this paper comprises 18 key informant interviews with (regional) commercial directors of leading vegetable seed companies active in SSA.The commercial lead for SSA was targeted as an interviewee because this person is most likely to have an in-depth understanding of the current and future business of the company in the region.In the absence of a regional commercial lead, the Chief Commercial Officer (CCO) or Chief Executive Officer (CEO) was targeted.This qualitative dataset is unique thanks to the insider status and community membership of the authors (Dwyer and Buckle, 2009).Insider research builds on a shared language and experience, which tends to result in increased trust and openness of participants vis-à-vis the researcher.Moreover, the vegetable seed companies were reassured that no references would be made to individual company data in publications.Therefore, the methodology focuses on the identification of trends and patterns, with data analysis tools chosen accordingly.

Data collection
Our sample was based on the Access to Seeds Index and covers a significant share and diverse range of the companies.It includes 10 out of all 13 global companies (Advanta, BASF (Nunhems), Bejo, East-West Seed, Enza Zaden, Limagrain, Rijk Zwaan, Sakata, Syngenta and Takii).All 13 global companies were initially targeted, but one company did not respond.Corteva Agriscience was excluded because they do not focus on vegetable crops.KWS was included but it reported to not be active in SSA for vegetables; KWS sold its OPV vegetable portfolio to Zasco, which was then included in the sample.Furthermore, it includes four local and regional seed companies (SeedCo, Agriscope, Kenya Highland Seed, and Victoria Seeds).Additionally, four smaller global seed companies were interviewed that specialize in seed production or dissemination (Bakker Brothers, EASI Seeds, SUBA, and Zasco).In total, the sample consists of 18 vegetable seed companies active in SSA.We included a diversity of actors in terms of company size, crop type, seed type, ownership structure and business operations in sub-Saharan Africa.
The interview questions focused on the four seed system functions discussed previously.For variety development, questions were asked about breeding activities and product portfolio in terms of crops and seed types.For seed production, questions focused on production, processing, and trade.For seed dissemination, questions addressed country priorities, the preferred market entry model, partnerships with distributors and responsibilities of local teams.For crop production and use, questions addressed the support provided to (smallholder) farmers in the form of extension services or capacity building.Finally, questions were asked about partnerships with public, private or development actors to zoom in on potential collaborations and role divisions.The main objective was to find out which seed system functions the companies prioritized in their strategy.Interviews were conducted in-person (if possible), or virtually, and lasted two hours.

Data analysis
The two qualitative methods (thematic analysis and ideal-type analysis) were selected to subtract general results from the data without referring to individual companies.Firstly, thematic analysis was used to develop a shared perspective of the leading seed companies on vegetable seed sector development in SSA.The focus was on themes as meaning-based patterns: "reflecting a pattern of shared meaning, organized around a core concept or idea" (Braun et al., 2019).Secondly, ideal-type analysis was used to define typologies to categorize leading vegetable seed companies active in the region.The ideal type, which was introduced by Max Weber, has evolved over time as a conceptual tool in sociology (Swedberg, 2018); for instance, Stapley et al. (2022) explain how ideal-type analysis serves to understand interviewees based on within-group similarities and between-group differences.
For both thematic and ideal-type analysis, two steps of data analysis were taken; familiarization with the data and reconstruction of the cases.During the reconstruction step, we prepared summaries which were shared with respondents for validation.For thematic analysis, the next steps were reflexive coding and constructing themes (Braun et al., 2019).For the ideal-type analysis, we formulated the ideal types, identified optimal cases, wrote ideal type descriptions, checked credibility, and carried out comparisons (Stapley et al., 2022), evaluating whether the competitors listed by companies were placed in the same group.

The private sector perspective
The thematic analysis highlights three general patterns.The seed companies focused on the following: commercial farmers and crops; seed types; and hybrid transitions.

Commercial focus
The companies reported that they sell seed to 'commercial farmers' who produce for the market and that this can include smallholders.They explained that the extent to which the produce of farmers is meant for the market varies, but that farmers can start investing in seed if they can sell at least part of their harvest.The companies often work with farmer typologies, which they usually define based on the technology level of the farm system and intended market for the harvested produce; these factors determine which seed type a farmer is encouraged to buy.This commercial lens is also applied to crops.All crops, both global and local vegetables, are interesting for seed companies if they are produced commercially.Currently, most seed companies are mainly focused on tomato and onion.In SSA, these are the only vegetable crops for which large, stable markets exist, meaning that farmers purchase seed frequently.Several companies reported that tomato and onion seed sales account for over half of their revenues.However, some companies specialize in other crops groups like brassicas or pumpkins, building on existing breeding programmes and a strong market position.

Seed types and hybrid transitions
Hybrid transitions in vegetable crops are witnessed, anticipated, and promoted by seed companies.The statements were varied, but they were all rather similar: "we are transitioning", "farmers are learning", "the future is hybrid" and "it can go fast."These statements were made in response to different questions about company business strategy.Companies mention hybrid transitions being a raison d'être, market entries requiring a certain level of hybridization, product portfolios explaining why OPVs were phased out, and capacity building to enable farmers to adopt hybrids.Companies distinguished between farm-saved seed and OPVs; OPVs and hybrids; and standard hybrids and advanced hybrids.As one company representative explained it: "in low-tech markets, you start with OPVs, continue with low-value hybrids and slowly introduce high-value hybrids."Another company stated: "we used to have OPVs and super hybrids.Now we are demonstrating the benefits of cheap hybrids."These statements show that seed companies try to create a step-by-step product portfolio for farmers.There is a major gap between OPVs and super hybrids in terms of pricing and skills and this is the reason why the aforementioned company stated that they had learned that it is necessary to have cheaper hybrids in their product portfolio as a stepping stone.Most companies aim to offer farmers the full spectrum of seed types and ensure farmers can work their way up through the product portfolio.
Companies seem willing and able to invest in the creation of demand for hybrid seed, while investing in OPVs seems unpopular.Some companies reported that margins on hybrid seed are higher than margins on OPVs, others stressed the quality difference between OPVs and hybrids.OPVs are considered 'gateway products' for most crops, after which farmers transition to hybrids with more beneficial traits.Companies reported that they do not invest in promotional activities for OPVs because the varieties are well-known, often old, and similar to their competitors' products.Hybrids are company-specific varieties and hence, others cannot leach on marketing campaigns selling the same product.Vegetable seed companies have successfully created seed markets for some self-fertilizing crops like yardlong beans, but the success of the yardlong bean was deemed the result of the popularity of hybrid varieties of other crops sold under the same brand: hybrids allow a seed company to distinguish itself by increasing brand awareness.Please note that seed companies generally put self-fertilizing crops like beans in the same category as open-pollinated varieties of crossfertilizing crops because they may have to compete with farm-saved seeds, which reduces commercial seed prices unless plant variety protection is effective in such markets.
Several companies explained that demand for hybrids is driven by improved resistance to pest and disease pressures.They stated that it is key to create added value for farmers in the form of resistances (or marketability), because farmers will not buy hybrids if they are not clearly better than OPV alternatives.Intensification of production plays a role here because it increases such pressures.One respondent explained how it has become impossible to grow traditional tomato varieties in certain areas in Kenya because the disease pressure has become too high.Moreover, the improved resistance of hybrids allows for off-season production during which market prices are much higher.Farmers can make more money if they produce during these challenging circumstances.In this case, farmers might use 'ordinary' seed during the peak season when they fetch low prices and invest in 'extraordinary' seed during the off-season.

Vision for seed sector development
The private sector's perspective on vegetable seed sector development follows a linear trajectory in which farmers adopt increasingly technologically advanced seed types as they become increasingly market oriented.Fig. 3 illustrates the conceptualization of seed sector development that we derived from the company interviews.The horizontal axis shows commercial formalization of the seed, farm and market systems.The vertical axis shows the technical support that companies need to supply to farmers.The level of commercial formalization represents a decisive factor: companies focus on commercial crops including local crops like African eggplant, African kale, and okra if there is a growing market matching their product profiles and business strategies.
Our analysis of interviews with companies clarified that they need to provide a growing amount of resources as the farmers move from OPV, to standard hybrid, to advanced hybrid seed.These transitions, for example from OPV to hybrid, require variety development, awareness raising and capacity building.We have illustrated this in Fig. 3; the fluctuating line indicates the resources needed to realize transitions between seed types.Some companies allocate significant resources in the form of long-term investments, but companies also point at the responsibility of the public sector to finance or implement interventions such as extension services and pre-competitive research.The two dotted lines in the background indicate rising seed prices and a decreasing number of customers of seed companies.Not all farmers transition to more technologically advanced seed types, which means that the number of customers of seed companies in the advanced segment is lower than in the earlier phases.
Furthermore, Fig. 3 illustrates how companies distinguish between four phases of market-driven seed sector development based on seed type: the phases represent transitions to new seed types.In phase zero, farmers use farm-saved seed and/or free seed supplied by NGOs or the government.Transitioning to the first phase, demand is created for OPVs, meaning that farmers are willing to pay.Once demand has been established, seed companies can sell their products via agrodealers.Transitioning to the second phase, demand is created for standard hybrids.Companies may invest in capacity building of farmers to enable them to earn a return on the investment in hybrid seed.Again, after demand creation, fewer resources are required to sell standard hybrids.In the final phase, the transition to advanced hybrids is made.Seed companies in this segment continuously need to provide tailored services that focus on a more limited number of farmers.For this reason, they pursue integrated value chains in which they build strong customer relationships and maintain strict quality control.Hence, Fig. 3 illustrates that in the interviews the companies reported a more selective customer base for advanced hybrids, which require a higher technology level and ability to invest.
It is important to note that these phases can run in parallel while demand for all seed types co-exists: the same farmer can use different types of seed for different vegetables.Farmers also switch back and forth between seed types as they have different preferences and face different (financial) conditions in each season.They may also buy combinations of seed types for the same crop to serve different market segments during the same season or grow the same crop in different seasons.Still, many seed companies are convinced that once farmers reach a certain level of professionalism in terms of production and market orientation, they stick with hybrids.Moreover, they are convinced that the vegetable sector in SSA is generally moving in this direction.

Company typologies
Using ideal-type analysis, four types of vegetable seed companies were identified.The indicators selected to define these are shown in Table 1: four distinct company profiles with different business models.These business models are based on their primary specialization in a particular seed system function (variety development, seed production, seed dissemination, or seed use).This does not imply that the company has not taken on other system functions.

Variety development
Variety development companies are research and development (R&D) companies with breeding programmes as the backbone of their company.As high-tech companies, they focus on the development of advanced hybrids and usually do not have any OPVs in their portfolios except for certain self-fertilizing crops like lettuce.Variety development companies consider OPVs to be a separate type of business focused on price rather than quality competition.High-value hybrid seed is usually sold per seed (rather than per gram or kg) to ensure the farmer knows the investment and profit made per plant.Companies explained that hybrids are better-performing varieties with more beneficial traits.Some explained that their R&D investments are very high, and it is necessary to gain a return on this investment: it is easier to do this via hybrids, which provide natural intellectual property protection.Breeding programmes are usually global but allow for the generation of varieties for specific environments and markets.The focus lies on global crops, for which markets are sufficiently large to gain a return on R&D investments.Moreover, focus lies on a limited number of core crops in which the company has specialized.Specialization creates opportunities; companies can sell licenses to each other.After the company selects its products, there may be plenty of varieties left for licensing.Variety development companies have integrated seed value chains and control the seed production in-house or through licensed multipliers.Seed production is done all over the world in climatic zones that are suitable for the crop, while seed processing is usually done in one or few central locations: a degree of decentralization is essential to cope with environmental or policy risks, but it bears scale disadvantages.Variety development companies do not partake in seed tenders and are often outspoken opponents of tenders because farmers should get access to quality seed and learn the value of quality seed.Their customers tend to be professional commercial farmers.Generally, the SSA market is not a top-priority for these companies because the number of farmers able to invest in and make use of their high-tech high-value products is limited.Some companies frame their presence in the region as part of their corporate social responsibility (CSR) agenda or as a long-term investment.

Seed production
For the formal system, vegetable seed production is concentrated in regions with optimal agroecological conditions rather than in the target market where the seed sales occur.Seed production companies do not invest in R&D but access older 'free' or public sector varieties to produce OPV seed.Also, they may receive parental lines from other seed companies to contract-produce OPV or (hybrid) seed for them.Therefore, companies specialized in seed production sell their own branded seed but also produce seed for other companies or NGOs/IGOs.In case of the latter, the seed packaging often carry the logo of their customer and not theirs.Also, they produce seed of a variety and quality level chosen by their customer.The general trend of land scarcity and increasing quality demands makes it more difficult to identify trusted producers in optimal seed production locations.Seed production companies require a certain scale of production and sufficient distance between them and other seed (or agricultural) producers.Many seed companies struggle to scale their own production facilities because it requires considerable financial resources and a large customer network.Moreover, predicting demand can be difficult, so contracting out seed production is a risk mitigation strategy: companies are willing to pay more for such contracts because they can avoid producing too much and ending up being stuck with perishable seed in storage.Some seed production companies have seed tenders as their main business model.Tenders are instigated by NGOs or IGOs like the Food and Agricultural Organization (FAO) and the choice of bid is usually price-driven provided that standard quality and packaging requirements are met.Seed production companies are only responsible for producing the seed in bulk and their buyer is responsible for delivery.Companies that specialize in seed production benefit from the tenders because of profit margins, large quantities, and low business risks.

Seed dissemination
Seed dissemination companies focus on the development of a distribution network: they usually do not invest in R&D or produce their own seed.Variety development is deemed too expensive and/or unnecessary as there is an abundant supply of varieties available in the public domain or accessible via licensing agreements.Dissemination companies can be exclusive representatives of other seed companies, or can sell under their own brand.Their product portfolio includes OPVs; public (usually older) varieties; and standard hybrids bought or produced under license from other companies.Seed production can be contracted to specialized (local) multipliers.The focus is on trade, delivery, and sales; their distributor and/or farmer network provides them with an understanding of local demand.The companies explained that short feedback loops with farmers allow them to select varieties, which match their needs.A distribution company stressed that they mostly compete by bringing the product close to farmers "at the right price, at the right time."These companies may move beyond standard sales channels and set up innovative distribution systems, working with tuktuks, motorcycles or mobile shops to resolve last-mile challenges.Dissemination companies tend to also sell seed for field crops and other agricultural inputs to build sufficient scale for a profitable business.They also sell in quantities that fit the needs of a variety of farmers using small package sizes.Seed dissemination companies may participate in seed tenders as well.

Seed use
Companies specialized in seed use support farmers throughout the crop cycle, offering technical advice and organizing trainings.They have OPVs and hybrids in their portfolio and sell some varieties per seed and others per gram.In comparison to variety development companies, their portfolio might not include the most advanced varieties.This is because they spread their efforts and have local and global crops in their portfolio rather than focusing on core crops.Hybrid seed production is usually done in-house, while OPV production can be outsourced.Creating demand for more advanced products requires 'seed use' companies to work closely with the farmers.The companies explained that farmers often need to develop their horticultural skills to unlock the full potential of quality seed and gain a return on their investment.This support can be offered by the company's extension agents or corporate (not-for-profit) foundations.The creation of a separate entity marks the division between commercial and pre-commercial capacity building activities more clearly.Besides capacity building regarding seed use, companies may provide farmers with support in terms of marketing, linking them with traders or processors to improve market access for their products.Seed use companies do not participate in seed tenders because these do not result in financially sustainable seed systems.They may receive external (public) funds to provide extension services to (smallholder) farmers who might become their customers in the future.

Evolving business models
The four company types play different roles in market-driven seed sector development.Seed production and dissemination companies are both involved in the provision of free seed via seed tenders.Demand creation for OPVs is mostly done by seed dissemination and seed use companies.Transitions to standard hybrid seed is realized by companies with mixed product portfolios including OPVs and hybrids, which are dissemination and seed use companies.Variety development companies will compete to supply select groups of farmers that can transition to advanced hybrids.
As seed sector development progresses in SSA, companies start to invest in seed system functions beyond their specialization and move into new segments.Variety development companies invest in local teams for distribution, and local adaptation of core crops or local commercial crops.A company focused on advanced hybrids might add a standard hybrid to their portfolio to reach a new group of customers building brand awareness earlier on.Seed dissemination companies seek to invest in variety development, launching breeding programmes, often in collaboration with organizations like the World Vegetable Center or global partner companies.Rather than distributing brands of other companies, they now start to sell their own varieties under their own brand.Moreover, they want their own hybrids to ensure future competitiveness.Variety development companies seem to enjoy an advantage here in terms of human and technological resources.The ability of seed dissemination companies, often local companies, to shift gears and take on additional seed system functions seems more limited.Growth can occur through expanding one's own business or mergers and acquisitions.For example, an international company may prefer to take over a local company with a strong distribution network and local product portfolio rather than developing their own.

Discussion
Most narratives on seed sector development start with smallholders, but the 'smallholder farmer' is an ambiguous concept in vegetable farming systems, and the focus of market-driven vegetable seed sector development is on commercial farmers, whether small or large.The FAO defines smallholders as those cultivating up to 10 ha (2013).While this definition can be useful for field crops, it seems out of place when it comes to vegetable seed sector development; ideally, a vegetable farm is small and highly productive.Thus, smallholders may be better defined based on the level of subsistence versus market orientation rather than in terms of land sizes or other resources (Murphy, 2010;Fan et al., 2013).
The focus of seed companies is also on commercial crops, both global and local.Seed companies tend to initially direct their attention to tomato and onion, the main commercial vegetables, and worldwide production has a similar trend; tomato is the most important vegetable, with 16 % of global production, followed by onion (including shallots) with 9 % (FAO, 2022).However, a variety of vegetables is needed to support agrobiodiversity and diverse diets (Nabuuma et al., 2022).In terms of policy interventions, Afari-Sefa et al. ( 2012) point at the need to develop new, nutrient-dense varieties of local and global vegetable for which (smallholder) farmers can find urban and rural markets.For (local) niche crops, interventions could focus on strengthening informal commercial seed systems (Sperling and Almekinders, 2023).
Vegetable seed companies are primarily focused on hybrids.While companies seem willing and able to fund the transition from OPVs to hybrids, the transition from farm-saved seed to the purchasing of quality seed of OPVs seems a less commercially appealing investment.Companies seem reluctant to invest in the breeding and marketing of OPVs, seeing them as challenging investments on which to earn returns.Publicprivate partnerships can offer a solution in this regard: the World Vegetable Center is developing open-source OPVs (and hybrids) of global and local vegetables, which companies can start producing directly or use in their own breeding programmes.Interventions could also provide support to emerging (local) companies focused on OPVs to facilitate this transition (Kugbei and Bishaw, 2002).
Meanwhile, market demand for hybrid vegetable seed is driven by food systems.Seed companies stress that farmers only buy expensive hybrid seed if there is added financial value.In the vegetable sector, this value is often created by off-season production during natural peaks in disease pressure.It is also created by peaks in disease pressure resulting from intensified production, as is the case with tomato in Kenya (Avedi et al., 2022).Additionally, climate change has already altered weather patterns, increasing biotic and abiotic stress levels.Together these developments will fuel demand for technologically advanced seed.A future challenge will be to develop viable business models for niche markets in terms of farming systems and crop types (Dinssa et al., 2015).
Fig. 4 shows a reduced number of customers for seed companies selling advanced hybrids.In line with the private sector's vision, Fan and Rue (2020) argue that smallholders should move up or move out: they should raise farm productivity or find off-farm employment.Similarly, seed companies anticipate rising farm productivity for a select group of farmers following the professionalization of seed, farm and market systems, which all goes hand-in-hand.However, some contest this view, pointing out that there is a lack of off-farm jobs in SSA if moving out, and a lack of incentives for local market production if moving up (Giller et al., 2021).A plurality of seed systems is needed to serve a diversity of farmers, for those who move up, but also for those who cannot move up or out.
Most vegetable seed companies seek to expand their businesses by moving into new market segments or seed system functions.In Europe, such dynamics have reduced the number of seed companies in the past 50 years (Schenkelaars et al., 2011).Still, in OECD countries, start-ups also continue to emerge, and challenge established players, while in Asia, global companies fuelled vegetable seed sector development after which both local and global companies benefitted from an established market (Schreinemachers et al., 2021).In the Netherlands, for instance, new companies have been founded focusing either on specific vegetable crops, such as Limseed (asparagus) and Novisem (celeriac, endive, and others) or specific markets for main crops such as Axia (tomato) and Westland Seed (peppers).Therefore, besides a plurality of seed systems, a range of seed companies may continue to serve different farmers and market segments.

Conclusion
In this paper, we have zoomed in on market-driven transitions, investigated how business models of leading vegetable seed companies contribute to seed sector development in SSA, and discussed several interventions aimed at enhancing the positive impact of market-driven vegetable seed sector development.We found that companies foresee a linear trajectory in which public and private investments are made to enable farmers to adopt increasingly technologically advanced seed types.Their perspective resembles the view of Douglas (1980), that seed system development moves from informal to formal systems.In this shared vision, vegetable seed companies play different roles and specialize in different seed system functions.The current coexistence of and collaboration between different (private) actors in the vegetable seed sector contribute to plurality and interaction, which is in line with an integrated approach to seed sector development.However, it is not a static condition; company roles appear to evolve with expanding business models in terms of system functions and market segments.Furthermore, while the dominant focus of seed companies on commercial farmers, commercial crops and hybrid varieties maintains the plurality of seed systems, this focus does not encourage interaction between seed systems.The general objective should be to increase farmers' access and choice in terms of quality seed of improved varieties through innovative and inclusive business models.In this way, the contribution of vegetables to healthy diets and farmer incomes can be enhanced in the work towards Zero Hunger.

Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Vegetable seed exports from Europe to SSA increased from less than 20 million euros in 2002 to close to 100 million euros in 2022.The Netherlands and France are the largest exporters, both accounting for around 40 % of the European vegetable seed exports to SSA in terms of value in 2022.Moreover, the value of seed exports increased from 19 euros per kg of seed in 2002 compared to 49 euros in 2022.The rising value of seed exports per kg differs greatly within the EU, with Italy exporting relatively cheap seeds while the Netherlands exports more expensive seeds.While the export value per kg has stayed relatively similar over the years in Italy, the export value per kg has risen for Dutch vegetable seed.

Fig. 3 .
Fig. 3. Seed company perspectives on seed sector development based on the authors' conceptual representation based on analysis of the 18 key informant interviews.

Fig. 4 .
Fig. 4. Two-by-two matrix of company typologies based on key indicators.

Table 1
Four vegetable seed company typologies in low-tech markets.