PVS in Developing Countries

Aid organisations often do participatory varietal selection (PVS) trials with smallholders in developing countries as a way of first selecting the more suitable varieties for their clients, for example, smallholders, and then to introduce the new varieties to them. Their extensionists choose the varieties to be assessed except for local checks. The smallholders grow, consume and/ or sell the new varieties and share feedback to the aid organisation via the extensionists.

One of its earliest and best-known successes was the introduction and selection of climbing bean varieties for Rwandan smallholders (Louise Sperling, 1996). Rwanda has a very high population density and the researchers knew that climbing beans had a greater yield than the dwarf varieties then grown and the extra food this achieved would more than justify the extra effort of staking them.

The Rwandan smallholders grew selected climbing bean varieties in their smallholdings to see how well each would grow and their households tested the eating acceptability of the beans; both provided feedback to Louise.

Several climbing bean varieties were approved and subsequently adopted by the smallholders. They are now widely grown in Rwanda, confirming the success of PVS.

This work involved international research using overseas aid. Its ‘top-down’ nature (extensionists choosing the crop and varieties) has the advantage of exploiting their worldwide knowledge of new varieties.

I was working in Uganda at Namulonge Research Station with the national Sweet Potato Programme when I read of this work. At that time, most Ugandan sweet potato varieties were susceptible to a severe disease called sweet potato virus disease but the Sweet Potato Programme had recently bred five varieties that were resistant.

We decided to use PVS to trial our resistant sweet potato varieties with smallholders. Before our project, most sweet potato in Uganda was grown in the Eastern Region where sweet potato virus disease is rare. The national Sweet Potato Programme was already disseminating the varieties there.

Our trials were in Central Uganda where sweet potato virus disease was rampant so we thought all our varieties would be winners: we were really thinking of the trials as demonstrations for the smallholders!

Our trials were in several locations and, at each, the owners planted small plots of the new varieties along with their current favourite in their holdings. All the yield belonged to the smallholder; she and her family probably ate most of it and sold the rest. And we found out what they thought of each variety.

All the varieties resisted the virus. Yet only NASPOT 1 was approved by the smallholders.

A sweet potato farmer showing off NASPOT 1

Yet NASPOT 1 absolutely hit the jackpot. It is now grown intensively in Central Uganda, close to the main market in the capitol Kampala. For several years it was the most widely grown variety in Uganda and also spread to neighbouring countries.

To our then amazement, the smallholders in our PVS trial had over fifty different reasons why they liked/ didn’t like a particular variety; the plant breeder had selected for only half-a-dozen or so traits.

So perhaps we shouldn’t have been surprised that only NASPOT 1 was selected! We were ‘lucky’ that we used a PVS approach. Involving the smallholders in this way allowed us to understand why this was so.


The next webpage explains how PPB then became more widely used in developed countries amongst specialist growers, especially organic growers.