Degeneration of Sweet Potato Seed in Tanzania: Can Cleaned-up, Virus-tested Seed Help?

Summary

This research investigated how virus-free planting material of sweetpotato can be incorporated into smallholder farming systems in Tanzania. Sweetpotato production in Tanzania is constrained by viruses which can lead up to 100% yieldlosses. Being vegetatively propagated, sweetpotato accumulates viruses across generations.The accumulation of viruses in the propagating material leads to progressive yield loss and is called seed degeneration. Use of virus-free seed disseminated through a formal system is one of the options to address this. However, clean seed can get infected once in the field and it is not known how it will perform following several seasons of on-farm propagation. Moreover, successful use of clean seed requires an understanding of the current practices that farmers use when sourcing sweetpotato seed. This research will help seed systems practitioners to understand how to effectively promote adoption of virus-free sweetpotato seed considering agroecology, farmers’ experiences and seedsourcing patterns.