AN EFFICIENT METHOD FOR PRODUCTION OF DIPLOID CANTALOUPE CHARENTAIS MELON (CUCUMIS-MELO L VAR CANTALUPENSIS) BY SOMATIC EMBRYOGENESIS

This paper describes a system of regeneration that allows somatic embr yo formation at high frequency from mature cotyledon explants of Cucum is melo L. var. cantalupensis (cv. Vedrantais). Several different grow th factors, environmental conditions and carbohydrate sources were ana lysed in order to improve somatic embryogenesis in this cultivar. Best conditions lead to the definition of a two step protocol including a 2 week period of embryogenesis induction in Murashige and Skoog's medi um supplemented with 30 g l(-1) glucose, 10 mu M 2,3-dichlorophenoxyac etic acid and 0.5 mu M 6-benzylaminopurine (IM medium) in the darkness , followed by a period of embryo development on the same medium withou t hormone (DM medium), under a 16/8 h light/dark photoperiod. After 4 weeks of culture, somatic embryos were converted into plantlets on the DM medium in a Magenta vessel. Using this optimized protocol, 42% of the explants were able to generate embryos with an average of 7.8 embr yos per explant. More than 60% of the plants generated from these embr yos were diploid, exhibited the phenotype expected and gave well-devel oped fruit. (C) 1997 Elsevier Science B.V.