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The storage of a clone ofColocasia esculenta at 28/24°C over a 12-h photoperiod in the absence of mannitol, was not feasible with transfer intervals of more than eight months. Mannitol had a positive effect on survival at this temperature, but caused abnormalities at high concentrations. At 9°C in total darkness,C. esculenta could be stored for more than eight years with transfer intervals of approximately three years. After this period, more than 90% of the cultures showed living shoots, but not all shoots per culture showed regrowth. Cultures which were transferred three times during the experimental period, had a significantly (γ=0.05) lower number of regrowing shoots than cultures which were transferred twice. This might be due to the fact that the former cultures were transferred at a less favourable developmental stage. The addition of mannitol to the storage medium did not improve survival and regrowth, nor did a more gradual lowering of the temperature to 9°C.

Four Indonesian and two Latin-American cassava genotypes (Manihot esculenta Crantz), were evaluated for their ability to develop somatic embryos from young leaf lobes. All genotypes formed somatic embryos but they differed in the frequency of embryos induced. The best genotypes, M. Col 22 and Tjurug, produced germinating embryos (GE) on 81% (22.1 GE/initial leaf lobe) and 46% (4.3 GE/initial leaf lobe) of the cultured leaf lobes, respectively. Up to 57% of the germinating embryos of M. Col 22 and 12% of Tjurug produced either normal or malformed shoots. Most malformed shoots developed into shoots with normal morphology after prolonged culture. All shoots formed roots after transfer to medium without BAP. Roots of all normal and most malformed regenerants had the original ploidy level (2n=36). Regardless of whether the plants were multipliedin vitro (150 plants) or in the greenhouse (30 plants) there were no morphological differences compared to parent plants.