High-efficiency somatic embryogenesis and plant regeneration from suspension cultures of grapevine

Embryogenic suspensions of grapevine (Vitis vinifera L.) were initiated from somatic embryos of 'Thompson Seedless' and 'Chardonnay'. Suspension cultures consisted of proembryonic masses (PEM) that proliferated without differentiation in a medium containing 2,4-dichlorophenoxyacetic acid (2,4-D). 'Chardonnay' somatic embryos developed fully from PEMs following subculture in medium without 2,4-D; however, somatic embryo development did not advance beyond the heart stage in 'Thompson Seedless' suspension cultures. Highly synchronized development of somatic embryos was obtained by inoculating <960-mu m PEMs into liquid medium without 2,4-D. Somatic embryos were also produced in large numbers from suspension-derived PEMs of both cultivars on semisolid medium lacking 2,4-D. Somatic embryos matured and regenerated into plants in MS basal medium containing 3% sucrose. Using this method more than 60% of the somatic embryos regenerated plants. More than 90% of the regenerated plants were successfully transferred to the greenhouse.