Effect of Different Medium and Sucrose Concentrations on Germination of Somatic Embryos in Grape A.Y. Elidemir, H. I. Uzun and A. Bayir Akdeniz University, Faculty of Agriculture, Department of Horticulture, 07070-Antalya,Turkey Keywords: Vitis vinifera, in vitro culture, culture medium, embryo stages, germination Abstract The study was aimed to obtain effect of different medium and sucrose concentrations on germination of somatic embryos of grape. Direct somatic embryogenesis from cotyledone of grape hybrid was obtained in E20A medium supplemented with 0.01 mg/l IAA. Somatic embryos were cultured in different stages (globular, heart and torpedo). They were germinated in different medium (E20A, N&N and C medium) and different sucrose concentrations (10, 30, 50 and 70 g/l). The germination rate ranged from 23% to 95% in all medium. INTRODUCTION The genotype has been proved the most relevant component of morphogenic response within Vitis genus (Bouquet et al. 1982, Mauro et al. 1986). Somatic embryogenesis and organogenesis have been obtained from different explants in some Vitis species (Martinelli et al. 1993, Mozsar and Sule 1994) and hybrids (Clog et al. 1990). Somatic embryos are the best resources for stable plants productions in Vitis genus (Martinelli et al. 1996). Somatic embryogenesis is a rapid propagation method and an important tool in genetic improvement using molecular techniques (Bajaj 1986). However, the conversion of somatic embryos of Vitis into mature grape plantlets has proven to be difficult (Gray 1989, Perl et al. 1995). Somatic embryogenesis in the grapevine (Mullins and Srinivasan 1976) has great potential for plant improvement both for generating random genetic variation (somaclonal variation) within existing cultivars and as a tool for directed genetic manipulation. On the other hand, a major obstacle to the exploration of somatic embryogenesis in Vitis was the poor germination of the embryos produced in vitro (Rajasekharan et al. 1982). Some progress has been made to increase germination rates, but the yields of plantlets is still low (Vilaplana and Mullins 1989). GA 3 promoted somatic embryo germination at 1.0 mg/l but inhibited the process at lower concentrations or when it is used in combination with BAP in N&N medium. MS- based media containing NAA or NAA + BAP, was supported plant development, but frequency was not greater than that observed on growth regulator-free N&N media (Stamp and Meredith 1988). The germination rate was increased from 10% to 60%. The medium modification permitted the regeneration of normal developed grapevine plantlets (Mozsar and Sule 1994). An efficient embryo-to-plant regeneration system must be in place in order to utilize embryogenic culture systems. Nevertheles, plant regeneration from grape somatic embryos is often difficult. Dehydration of grape somatic embryos impoved plant formation, but the percentage of embryos that formed plants was low (Gray 1987). Subculturing grape somatic embryos to medium with high osmoticum may improve embryo quality and subsequent plant development. The objective of this study was to identify the effect of different medium and sucrose concentrations on germination of somatic embryos in grape.