Managing sweetpotato seed degeneration: Farmers’ experiences, actions and seed sourcing strategies in Tanzania

Sweetpotato seed degeneration, mostly caused by virus infections, is a persistent constraint undermining crop yields and food security in Tanzania, where informal seed systems and seed recycling predominate. This study examined farmers’ perceptions of degeneration and the strategies they apply when crop performance declines. Data were collected through 37 in-depth interviews (20 women, 17 men) across four districts in the Lake Zone of Tanzania. Sixty-two percent (62%) of interviewed farmers had encountered degeneration, with women reporting notably higher incidence. Farmers associated degeneration with progressive yield decline, stunted vines and foliar symptoms indicative of virus infection. They attributed the declining performance to the variety becoming ‘tired’, without linking it to their seed multiplication or sourcing practices. Most respondents managed degeneration by replacing affected varieties with different ones acquired through social networks, rather than sourcing virus free planting material or rogueing symptomatic plants. Seed sourcing remained primarily non-monetary, embedded in norms of reciprocity and trust, particularly among close social contacts. While trained vine multipliers were viewed as important sources of quality seed, their use was sporadic and largely driven by scarcity. These findings underscore that strategies to address degeneration must integrate informal seed exchange networks with decentralised clean seed production, strengthen farmer knowledge and confidence in virus management and address the social and gender dynamics shaping seed sourcing decisions. Leveraging women's central role in sweetpotato production and social learning will be critical to sustainably improving seed health and enhancing the crop's contribution to household food security.