INITIATION AND MATURATION OF SOMATIC EMBRYOS OF SQUASH (CUCURBITO-PEPO)

Plant regeneration from tissue cultures of summer squash (Cucurbita pepo L. cv. YC60) has been observed. Embryogenic callus tissues were initiated when cotyledons of mature seeds were excised and cultured on Murashige and Skoog (MS) medium supplemented with either 22.7-mu-M 2,4-D or a combination of 4.7-mu-M 2,4,5-T, 4-mu-M BA, and 0.5-mu-M kinetin. Clusters of somatic embryos were found in callus tissue. Maturation of these somatic embryos was effected by transfer of embryogenic callus tissues to MS supplemented with 0.5-mu-M NAA and 0.25-mu-M kinetin. Regenerated mature plants were morphologically normal and set fruits containing seeds that germinated normally. Chemical names used: 6-benzylaminopurine (BA); 2,4-dichlorophenoxyacetic acid (2,4-D); alpha-naphthaleneacetic acid (NAA); 2,4,5-trichlorophenoxyacetic acid (2,4,5-T).