Somatic embryogenesis of pistachio from female flowers

Induction of somatic embryogenesis from the flower buds of pistachio (Pistacia vera L.) was studied with respect to growth regulators. Sixty-five percent of cultures formed embryogenic calli when placed on modified Murashige and Skoog medium containing 1 mg l(-1) benzylaminopurine. In contrast, thidiazuron and a-naphthalene acetic acid reduced embryogenesis. Some of the somatic embryos had fused hypocotyls or multiple cotyledons. Abscisic acid was not necessary for maturation. Fewer somatic embryos germinated with 0.5 mg l(-1) abscisic acid, but more converted into plantlets. Separate, morphologically normal, somatic embryos germinated on semi-solid germination medium, and developed into plantlets. Cytological analysis revealed a chromosome number of 2n = 2x = 30, similar to seedlings. The protocol described in this paper, for the induction of somatic embryos indirectly from female flowers of pistachio, represents a first step towards the production of clonal stocks.