Somatic embryogenesis from mature leaves of rose (Rosa sp.)

Several plant growth regulators (0.3-53.3 mu M 6-benzyladenine, 2,4-dichlor ophenoxyacetic acid, gibberellic acid, 3-indoleacetic acid, p-chlorophenoxy acetic acid, kinetin and alpha-naphthylacetic acid), alone or in combinatio n, and culture conditions were tested for their capacity to induce somatic embryogenesis from mature leaf and stem explants of rose (Rosa sp.) of four commercial rose cultivars (Baccara, Mercedes, Ronto and Soraya). Somatic e mbryos were only induced from mature leaf explants derived from Soraya on M urashige and Skoog (MS) medium supplemented with 53.5 mu M p-chlorophenoxya cetic acid and 4.6 mu M kinetin, although satisfactory callus induction rat es were obtained from all cultivars. After subculturing on the same medium, embryos at various developmental stages (globular, heart and torpedo shape d) were transferred for maturation onto a MS medium supplemented with 5.2 m u M 6-benzyladenine and 5.7 mu M 3-indoleacetic acid. Germination of mature embryos took place after subculturing them onto medium of the same composi tion. Plantlets regenerated from embryos and bearing three to four leaves w ere transferred to a greenhouse.