High-efficiency somatic embryogenesis and plant regeneration in California poppy, Eschscholzia californica Cham

 The development of a rapid protocol for high-efficiency somatic embryogenesis and plant regeneration from seed-derived embryogenic callus cultures of California poppy (Eschscholzia californica Cham.) is reported. The optimized procedure required less than 13 weeks from the initiation of seed cultures to the recovery of plantlets and involved the sequential transfer of cultures onto solid Murashige and Skoog basal medium containing three different combinations of growth regulators. All steps were performed at 25  °C. Friable primary callus was induced from seeds of E. californica cultured on medium supplemented with 1.0 mg l^-1 2,4-dichlorophenoxyacetic acid. The primary callus was transferred to medium containing 1.0 mg l^-1 1-naphthaleneacetic acid and 0.5 mg l^-1 6-benzylaminopurine to establish embryogenic callus and promote somatic embryogenesis. Regenerated plantlets were recovered after the conversion of somatic embryos on medium containing 0.05 mg l^-1 6-benzylaminopurine and showed normal development. Embryogenic callus was induced at a frequency of 85%, an average of 45 somatic embryos were produced per callus, 90% of the somatic embryos converted, and about 70% of the plantlets were recovered in soil. The growth rate of somatic embryo-derived shoots could be increased by gibberellic acid treatment, but the resulting plantlets were hyperhydritic.