Somatic embryogenesis in peanut (Arachis hypogaea L.): stimulation of direct differentiation of somatic embryos by forchlorfenuron (CPPU).

The ability of forchlorfenuron (CPPU), a substituted phenylurea compound, for inducing somatic embryogenesis in peanut (Arachis hypogaea L.) seedlings has been demonstrated. CPPU promoted somatic embryogenesis at a range of concentrations in all three peanut cultivars tested. Embryogenic response was dependent on applied CPPU concentrations. Exposure of seedlings for only two days to CPPU induced somatic embryogenesis, but the most effective treatment was to induce seed germination on media supplemented with either 2.5 or 4.0 μM CPPU and to maintain the seedlings on the same medium. Number of somatic embryos and the frequency of embryogenesis was higher for younger seedlings (up to 9 days), regardless of the CPPU concentrations and seedlings older than 21 days failed to produce somatic embryos. Removal of cotyledons from the seeds drastically reduced the embryogenic potential of the seedlings. Somatic embryos developed into whole plants following their separation and subculture on a medium lacking growth regulators. The induction of somatic embryos using CPPU as a sole growth regulator may provide a useful system to study the role of this compound in plant morphogenesis.