Control of Dioscorea alata microtuber dormancy and germination by jasmonic acid

Effects of appling exogenous jasmonic acid (JA) on the germination of Dioscorea alata L. microtubers were examined on Murashige and Skoog (MS) medium. Microtuber germination was promoted by JA (0.1 and 1 micromolar) supplemented to the culture medium but higher concentrations (30 and 100 micromolars) completely inhibited germination. When these inhibited microtubers were transferred to hormone-free medium, germination resumed. After transfer to greenhouse conditions, almost all plants (95%) from tubers previously cultivated on MS medium with 100 micromolars JA survived and all acclimatized plants had produced tubers after 8 months. It is concluded that depending on JA concentration, both the germination and dormancy processes in D. alata microtubers were affected. The release from dormancy is easily obtained by transferring dormant microtubers to hormone-free medium.