Science - May 27, 2004

Farmers have a good eye for sweet potatoes

Local farmers are very good at identifying superior new cultivars, and letting them participate in breeding programmes could improve results significantly, claims Dr Erna Abidin. During her PhD research in Uganda she discovered that farmer-selected varieties of sweet potato sometimes yield more than national bred cultivars.

“Taken as a group, farmer-selected varieties of sweet potato outperform the national bred cultivars with respect to both average yield and yield stability. This observation alone indicates the ability of farmers to reliably identify superior genotypes,” states Abidin. Born in Indonesia, she conducted her field research in north-eastern Uganda while working as a lecturer there at an agricultural college.

Sweet potato is an important staple food in Uganda. Farmers depend largely on local landraces. Abidin examined a farmer participatory approach to sweet potato breeding, which exploits the genetic diversity available in these races. Eleven farmer-selected varieties and five national Ugandan bred cultivars were evaluated for their performance and were compared to local farmer varieties in on-farm trials. Abidin conducted group discussions and individual interviews to assess the farmers’ competence and preferences.

The farmer-selected varieties performed well and proved superior under the local farm conditions. “This could be indicative of a fairly high level of precision with which farmers selected varieties in the preliminary on-station evaluation,” says Abidin. Farmers from different regions rank varieties in a different way, depending on their market orientation. “Farmers either emphasise criteria related to home-consumption or to commercial properties. Varieties to be sold on the market must have white peel and yellow flesh.”

To improve sweet potato breeding for resource-poor farmers in Uganda and surrounding regions, Abidin recommends increasing farmers’ participation by letting them identify promising landraces and select potential varieties. She suggests a three-year programme that includes on-farm trials to confirm consumer acceptance. Abidin: “This may prevent disappointment caused by newly released varieties in regions where they have not been tested properly or failure of adoption because they do not meet the specific preferences of local farmers.”

Dr Putri Ernawati Abidin defended her PhD thesis on 24 May. Her supervisors were Professor Piet Stam (Plant Breeding) and Professor Paul Struik (Crop Physiology).

Gert van Maanen