The Effects of Carbohydrate Source and Concentration on Somatic Embryogenesis of Strawberry (Fragaria x ananassa Duch.)

This experiment was performed to evaluate the effects of different types and concentrations of carbohydrate source on callus fresh weight, number of somatic embryos per embryonic explant and percentage of globular embryos developing into cotyledonary embryos from the leaf explants of three strawberry cultivars (Kurdistan, Paros and Camarosa). MS medium containing 1.0 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 mg/l 6-benzyladenine (BA) supplemented with three types of carbohydrates (sucrose, glucose and fructose) at concentration of 1.5%, 3%, 6%, 9% and 12% separately were tested. Among the different sugars tested, 6% sucrose was found superior not only for giving optimum embryo induction of embryonic culture but also a uniform embryo developmental stages. Maximum number of 11.68, 12.68 and 13.35 globular embryos per explant, 81.53, 87.65 and 86.35% of globular embryos developing into cotyledonary embryos obtained for the cultivars of Kurdistan, Paros and Camarosa, respectively. Sucrose also was the best for proliferation of embryonic tissue with an optimal concentration of 3%.