Induction of somatic embryogenesis and in vitro flowering from inflorescences of chamomile (Chamomilla recutita L)

A protocol has been developed for the induction of somatic embryogenesis fr om flower explants of chamomile (Chamomilla recuitita L.). The effects of s everal plant growth regulators [alpha-naphthylacetic acid (NAA), 2,4-dichlo rophenoxyacetic acid,, 6-benzyladenine (BA) and kinetin (Kin), alone or in combination] and the flower type (disk or ray flower) were investigated. Bo th types of flowers responded to the callus and shoot induction treatment, but formation of globular somatic embryos took place only on disk-flower-de rived explants after 2-4 weeks of culture on a Murashige and Skoog (MS) med ium supplemented either with 8.87 mu M BA and 1.07 mu M NAA or with 26.8 mu M NAA and 11.5 mu M Kin. However, fully developed, cotyledonary-stage soma tic embryos could be induced only on the NAA/Kin medium, 10 weeks after cul ture initiation. Germination of the embryos and plant re-generation took pl ace after subculture for 4-5 weeks onto medium of the same composition. Pla ntlets regenerated from embryos flowered in vitro in a MS medium supplement ed with 8.87 mu M BA and 1.07 NAA. The significance of the results with res pect to chamomile micropropagation and the utilization of wild populations in breeding programs is discussed.