The Triple S Method of Producing Sweet Potato Planting Material for Areas in Africa with Long Dry Seasons

Abstract

Ugandan farmers preferred vine cuttings from sweet potato (Ipomoea batatas (L) Lam.) plants maintained during the dry season in a swamp or by irrigation as planting material rather than cuttings from volunteer plants growing from unharvested roots. The latter were late and weevil-infested, though readily available. To improve their earliness, roots planted 5, 10, 15, or 25 cm below ground at the start of the dry season were watered from 5 or 10 weeks before the start of the rains. Only those planted 10 cm deep emerged satisfactorily; those watered for 10 weeks produced more vines. To improve survival, roots were stored under various conditions before planting and watering: roots stored in dry sand in a roofed building survived especially well and sprouted prolifically, producing many cuttings. This method of producing vine cuttings, called the Triple S method, was validated by farmers in the Lake Zone of Tanzania, which has a harsher climate than Uganda. In addition to providing farmers with ample early and healthy planting material for little and infrequent watering, it provided convenience and ownership. We would like to thank the many farmers and extension agents that supported us in Uganda and Tanzania but particularly Mr. Ekinyu and Mr. Sois. We also thank the Reaching End Users Project of HarvestPlus and the Sweet Potato Action for Security and Health in Africa Project of the International Potato Center. Dr. Ricardo Labarta assisted us with the design of the survey instrument.