Disseminating modern sweetpotato varieties using participatory variety demonstration trials on informal nodal multipliers’ fields at hub locations

It is shown for the first time how participatory variety demonstration (PVD) trials can establish modern varieties in informal seed systems in a developing country by targeting nodal multipliers occupying hub locations. A series of relatively few, small (each 36 m²) PVD trials was conducted over a period of 3 years in sweetpotato multipliers’ fields at three locations in Uganda; multipliers and farmers were encouraged to visit during crop growth and on field days; yields at final harvest and other traits considered important to multipliers and farmers were recorded. In the following dry season, the areas of the introduced varieties established in the lowland crops used by multipliers to conserve planting material were recorded. The two most popular varieties had a recorded area of about 1 ha each and were calculated to have increased sixfold annually from the trials; the next two occupied 0.5 ha each, confirming that the method is effective, cheap, and efficient.