PRODUCTION OF HIGH QUALITY SEEDLINGS BY IMMATURE ZYGOTIC EMBRYO CULTURE OF WASABIA JAPONICA MATSUM.

Abstract

Immature zygotic embryos of Wasabia japonica (var. Dalma) were isolated from immature seeds of field-grown plants and cultured on modified MS media supplemented with auxins and cytokinins. The stages of zygotic embryos were classified into torpedo, early cotyledonary, and late cotyledonary stages. The early cotyledonary zygotic embryos were more productive than the torpedo stage or late cotyledonary ones in somatic embryogenesis, and they also produced greater numbers of somatic embryos. At the early cotyledonary stage, the highest overall embryogenesis was achieved in basal media containing 2.0 mg.L -1 IAA. The generation of somatic embryos was best in media with 2.0 mg.L -1 of kinetin, and plantlets generated from somatic embryos had phenotypically normal leaves and roots. Shoots lacking roots were separated individually, and transferred to medium for multiple shoot and root formation. Rooting and root growth were best in media with 0.01 mg.L -1 IBA, and multiple shoots were produced in media containing BA. But, the combinations of BA and 0.01 mg.L -1 IBA showed little or no effect on rooting.