Effects of Gibberellic Acid (GA<sub>3</sub>) on Sprouting and Quality of Potato Seed Tubers in Diffused Light and Pit Storage Conditions
ABSTRACT Effects of gibberellic acid (GA3) on dormancy termination, sprouting and quality of potato ( Solanum tuberosum L.) seed tubers stored for 12 weeks in Diffused Light Store (DLS) and for 2 weeks in pit were determined. Potato genotypes (Tigoni, Asante, Dutch Robyjn, Kenya Karibu and Kenya Sifa) and GA3 at 0, 10, 20 and 30 mg kg-1 were used. Dormancy period was reduced to three weeks in all genotypes except Kenya Sifa, which sprouted after seven weeks following GA3 treatments in DLS. Increasing GA3 concentrations increased sprouting (%), number of sprouts per tuber, sprout length and vigor score. However differences among GA3 concentrations for these parameters were not observed. In the pit, the potato seed tubers sprouted within the two weeks of storage. Except for Kenya Sifa, GA3 had no effect on sprouting and vigor score; however, it increased number of sprouts per tuber and sprout length. Increase in GA3 concentration led to increase in rotting at 30 mg kg-1 of GA3 for Tigoni, Kenya Sifa and Kenya Karibu genotypes, under DLS. It is suggested that lower levels of GA3 of up to 20 mg kg-1 should be adopted for promotion of sprouting of potato seed tubers.