Mapping adoption dynamics of improved vegetable varieties in Ethiopia’s seed system using a system thinking approach

Abstract Access to high-quality improved variety seed is one of the key determinants of agricultural productivity, farmer income and resilience in smallholder farming systems. In Ethiopia and across Sub-Saharan Africa, vegetable seed systems remain fragmented and are characterized by limited domestic production, weak distribution networks, and high dependence on imported seed. This study applies a systems thinking approach to analyze the mechanisms shaping the adoption of improved vegetable varieties within Ethiopia’s seed sector. Using causal loop diagrams (CLDs), the analysis integrates evidence from an extensive literature review with survey data from 468 tomato-producing smallholder farmers in Ethiopia. The survey showed that 55% of farmers used improved varieties, while 45% used local varieties. Among farmers using local varieties, the main reported reasons were the high price of improved seed (46.8%), lack of awareness (25.9%), perceived pest resistance of local varieties (13.9%), and longer shelf life of local varieties (7.0%). The CLD was further contextualized through farmer survey evidence, a key informant interview with a seed sector specialist, and supporting scientific literature. The results identify three reinforcing feedback mechanisms influencing adoption: (i) productivity-profitability reinvestment, (ii) local seed enterprise development and seed-cost reduction, and (iii) accessibility of locally adapted varieties through participatory breeding and farmer-to-farmer seed exchange. A balancing feedback loop related to import dependency and high seed prices may constrain adoption by reducing affordability. The study contributes to the ISSD literature by moving beyond a descriptive discussion of seed-system integration and showing how economic, institutional, and knowledge-related factors interact to shape adoption dynamics. The findings suggest that strengthening local seed enterprises, participatory variety development, credit access and institutional linkages may serve as important leverage points for higher adoption of improved varieties.