Somatic embryogenesis and plant regeneration in culture of root segments of spinach (Spinacia oleracea L)

In order to establish an efficient system for in vitro plant regeneration of spinach, the explants and optimum culture conditions for somatic embryogenesis were investigated. When the explants from cotyledon, hypocotyl, root and leaf of seedlings were cultured on culture medium comprising of half-strength Murashige and Skoog's medium (1/2MS) containing 10 g/l sucrose, 10 mu M 1-naphthaleneacetic acid (NAA) and 0.1 mu M gibberellic acid (GA(3)), somatic embryos were most frequently formed on the root segments. Varieties expressing a high ability of embryogenesis from root segments were screened from 8 varieties. 'Jiromaru', 'Nihon' and 'Hoyo' showed a high frequency of embryo formation from the explants. The embryogenesis was examined using 6 types of culture media. Nitsch's and 1/2MS media supported embryogenesis with a higher efficiency than the MS, White's, B5 and SH media. The systems of plant regeneration from root explants established here would provide a useful system for vegetative propagation of female spinach plants.