Societal Impact Statement: Amid global challenges of food insecurity, poor nutrition, and climate change, neglected crops like amaranth are gaining renewed attention. We studied farmers' preferences for amaranth varieties across diverse geographical contexts to guide targeted breeding. Our results revealed significant variation in farmer preferences, emphasizing the need for context‐specific breeding strategies. These findings can support the development of improved amaranth varieties that meet local needs, expand economic opportunities—especially for women—promote healthier diets, and boost biodiversity. This work also offers a model for participatory research on opportunity crops, informing inclusive agricultural policies and sustainable development strategies across Africa and beyond.Summary: Opportunity crops, also known as neglected and underutilized species (NUS), offer benefits to diversify food systems with nutritious and climate‐resilient foods. A major limitation to incorporating these crops in farming systems is the lack of improved varieties, which impedes farmers from accessing quality planting materials of these crops. The study explored how citizen science methods can support demand‐driven breeding and seed production of NUS using leafy amaranth – a nutritious and hardy vegetable ‐ as a case study. The study identified farmer preferences and market segments, with particular attention to gender and social differentiation. We used the tricot approach to conduct participatory on‐farm trials of 14 varieties with 2,063 farmers from Benin, Mali, and Tanzania. We then analyzed farmer traits and varietal preferences in aggregate and among segments of farmers, using cluster analysis. Farmers' overall preferences for amaranth varieties were driven principally by plant survival, yield, leaf size, taste, and marketability. Distinct farmer segments (older women generalists, young women specialists, older men generalists, and young men specialists) preferred different varieties depending on gender and business orientation. The identified farmer segments, along with their unique variety preferences, provide valuable information for breeders and seed enterprises, and support demand‐driven amaranth breeding and seed system development. The methods used and lessons learned from our citizen science exercise can be applied to enhance breeding and seed supply of other opportunity crops that are underutilized in Africa and elsewhere.

Amaranth is a vegetable and grain crop with the potential to contribute to nutrition security and income generation. However, amaranth production in Benin faces several constraints, including the limited availability of improved varieties and access to high‐quality seed. The study aimed to (i) identify top‐performing varieties based on agronomic traits and (ii) identify farmer‐preferred amaranth traits and genotypes to guide variety recommendations for release. Ten amaranth genotypes were evaluated in five environments defined as the combination of locations (Abomey‐Calavi and Malanville) and years (2021, 2022, and 2023). Traits prioritization and variety ranking were done involving 41 experienced amaranth farmers. The analysis of variance revealed a significant genotype‐by‐environment interaction for fresh biomass yield, leaf length, and leaf width. Genotype was a major determinant of leaf length and leaf width, but had a lesser effect on fresh biomass yield. Genotypes A2002, IP‐5‐Sel, Madiira1, and Nguruma exhibited the most stable yield across environments. IP‐5‐Sel, A2004, and AC‐NL were the most stable genotypes for leaf width, while IP‐5‐Sel and Madiira1 were the most stable for leaf length. The five environments formed a single mega‐environment for fresh biomass yield and leaf width. The multi‐trait selection index identified Nguruma and Madiira2 as the top performers when considering fresh biomass yield and leaf parameters. Farmer‐preferred traits included marketability, branching, late flowering, and cooking quality. Based on these traits, the most preferred genotypes were Madiira2, AC‐NL, Nguruma, and Akeri. Combining the agronomic and farmer preferences, and the release status of the genotypes in West Africa, we recommended Madiira2, IP‐5‐Sel, Nguruma, AVAM1939, AC‐NL, and Akeri for release. The lines have been channeled into the variety release process in Benin.

Tomato is widely produced in Burkina Faso for its culinary, nutritional, and economic value. Tens of thousands of farmers are involved in its production throughout the country. However, they face significant biotic constraints that limit yields and income. In particular, tomato yellow leaf curl virus (TYLCV), a begomovirus transmitted by whiteflies (Bemisia tabaci), severely affects tomato production. This study evaluated the response of 13 tomato genotypes to tomato yellow leaf curl disease (TYLCD), including eight lines with different Ty resistance gene combinations; three local improved varieties, and two commercial varieties in western and central Burkina Faso. All genotypes developed TYLCD symptoms with considerable variability in genotypic responses. Four genotypes carrying a single gene, namely CLN4279O (Ty2), CLN4270I (Ty1/Ty3), CLN4270F (Ty1/Ty3), and CLN4018G (Ty2), exhibited the best field tolerance, with lower disease incidence and severity across sites. In contrast, genotype CLN4078A carrying two resistance genes (Ty1/Ty3 + Ty2), and the checks PETOMECH and ROMA VF were highly susceptible. Hierarchical clustering grouped the genotypes into four classes based on tolerance level and yield. These findings highlight the variability in resistance expression under field conditions and suggest possible interactions between host genotype, environmental factors, and virus populations. Broader multi-site evaluations, supported by molecular diagnostics to identify endemic TYLCV strains, are needed to refine the selection process.