New research has found that selecting seed potatoes directly from healthy mother plants can earn farmers a Sh30,000 bonus per hectare, at almost zero cost.

The norm among farmers is to select a portion from their own harvested potatoes which they then use as seeds. But with some of the seeds having inherited common potato diseases like brown rot from the soil, the cycle of low yields and poor potato quality is exacerbated, a phenomenon scientists say has been carried over the years, explaining why the potato has been doing poorly even with the massive potential it has in the region.

Peter Gildemacher, doctoral student at Wageningen University who has been working extensively in East Africa, is now advocating for the reintroduction of what was thought to be an unnecessary technique: selecting seed potatoes from parent plants that look healthy.

During field tests at 18 different locations he investigated the effect of this focused selection, compared with the norm of choosing seed-potatoes from the bulk of the harvested potatoes. The trials found that the yield increased by 30 per cent while disease caused by potato viruses fell by 35 to 40 per cent. A big advantage, Gildemacher said, is that the focused selection hardly costs the farmer anything, while the yield of one hectare of potatoes increases by Sh30,000 to Sh35,000.

Gildemacher has now trained smallholders in how to select the best seed-potatoes themselves. However, regular changing of seed-potatoes by introducing disease-free starting material from the specialised companies can result in higher yields still, he said.

Gildemacher's research findings are now being disseminated across Kenya and also in Ethiopia, Uganda, Rwanda, Malawi, Mozambique and Angola, which are also working to increase the productivity of the potato cultivation.

Potato farming is practiced by predominantly small scale farmers in Kenya, and employs more than 2.5 million people, delivering Kenya's second most important food crop after maize.

By Bob Koigi