Direct seeding of grapevine somatic embryos and regeneration of plants

Somatic embryos of grapevine (Vitis vinifera L.) 'Chardonnay' were produced from liquid suspension cultures. Mature somatic embryos were blot dried br iefly in the laminar flow hood and germinated directly in Magenta GA-7 Vess els(TM) containing one of the following potting media: (1) sand, (2) commer cial potting mixture (CPM), or (3) CPM overlaid with sand. Each vessel cont aining 20 ml of distilled water and the potting medium was sterilized by au toclaving for 30 min and cooled overnight before inoculating the somatic em bryos. Five somatic embryos were placed in each vessel under aseptic condit ions. The vessels were closed and incubated at 26 +/- 2 degreesC, 16 h phot operiod at 75 mu mol s(-1) m(-2) light intensity. Results revealed that CPM overlaid with sand was best for plant development. There was more contamin ation of somatic embryos on pure CPM. Since direct seeding bypasses at leas t two subcultures in agar medium, it has implications for use of somatic em bryos as 'synthetic seeds' for clonal plant production. This study shows th at somatic embryos of grapevine can be handled with some of the convenience of seeds, emphasizing the feasibility for further automating in vitro plan t production, which might be especially useful for new varieties where prop agation material is limited.