Effects of Sucrose and Gibberellic Acid on Growth and Survival of Local Potato (Solanum tuberosum L.) Varieties in vitro in Kenya

Tissue culture techniques’ have become useful technologies for producing disease & pest free seed potato (Solanum tuberosum L.) in the developed world. However, these techniques have yet to be standardized for locally produced potato varieties in Kenya.  Developing countries can also use these innovations for rapid multiplication of popular local seed material through rooted apical cuttings generated from either plantlets or micro tubers.  In vitro experiments were therefore conducted to determine the optimum concentration of sucrose and gibberellic acid for growth and survival of local potato varieties, namely, Shangi, Unica and Wanjiku.  The explants were cultured in Murashige and Skoog (MS) media supplemented with sucrose at a concentration of 20, 30 and 40 gL-1, while gibberellic acid was applied at a concentration of 0.2, 0.5 and 1.0 mgL-1. The study was laid out in a completely randomized design (CRD).  MS Medium with sucrose 40 gL-1and gibberellic acid 0.5 mgL-1 significantly enhanced shoot length, with the longest shoot  (10.3cm) being recorded for Wanjiku.  The same treatment also gave the highest plant survival of 90%. Murashige and Skoog media, added with 0.5 mgL-1 gibberellic acid along with 40 gL-1 sucrose is recommended for generating wanjiku, unica and shangi apical rooted cuttings because it gave the best improvement of in-vitro clonal growth.