Z.M. Kinyua, J.J. Smith, G.I. Oduor and J.N. Wachira
Tuber-borne diseases such as bacterial wilt, caused by Ralstonia solanacearum, are a major constraint to potato production due to poor availability of certified seed tubers to farmers-in
Kenya. On-farm trials were carried out to demonstrate the potential benefits of small potato multiplication plots to meet individual farmer demands for bacterial wilt-free tubers. Six farms with previous incidence of bacterial wilt were selected in Nyandarua District, Kenya. Certified seed tubers of varieties Tigoni and Roslin Tana were planted at two spacings, 20cm by 20cm (close spacing) and 75cm by 30cm (wide spacing), in plots measuring 3m by 3m on each farm. Data were recorded on tuber yields and disease incidences. Close spacing led to significantly more seed-size tubers per plot than wide spacing for both varieties. Land productivity under close spacing was 2.95 and 2.8 times higher than under wide spacing for varieties Tigoni and Roslin Tana, respectively. Bacterial wilt was noticed on only one farm.