An overview of progress in somatic embryogenesis and transformation in walnut.

Somatic embryogenesis has been achieved in 5 species of walnut. Cotyledons and zygotic embryos from immature fruit were routinely used as the explants for inducing somatic embryogenesis of walnut. Repetitive somatic embryogenesis has been used for the clonal production of in vitro plants and for gene transformation and regeneration of transgenic plants. Using Agrobacterium-mediated transformation of somatic embryos as a method, genes of interest have been transformed into walnut. The transgenic plants successfully expressed the transformed genes. An overview of the progress on those areas in walnut was presented in this article. It focuses on the points of induction of somatic embryogenesis and repetitive somatic embryogenesis as well as somatic embryos germination and their conversion. A model of u sing Agrobacterium-mediated transformation of somatic embryos for the production of transgenic plants in walnut was also presented.