Identification of somaclonal variants in proliferating shoot cultures of Senecio cruentus cv. Tokyo Daruma

Abstract

A protocol for in vitro propagation of cineraria (Senecio cruentus) was developed. The highest frequency of shoot proliferation was obtained from nodal explants cultured on Murashige and Skoog (MS) medium supplemented with 2.0 mg L-1 6-benzyladenine (BA) and 0.5 mg L-1 alpha-naphthalene acetic acid (NAA), with a mean number of 14 shoots per explant. A high concentration of BA (4.0 mg L-1) and repeated subcultures resulted in hyperhydric shoots. Decreasing the BA concentration to 1.0 mg L-1 in the culture medium eliminated hyperhydricity. The concentration of ammonium nitrate (NH4NO3) and temperature had marked effects on somaclonal variation. Variation was observed when the cultures were maintained at 15 A degrees C but not at 25 A degrees C. Variants with blue-colored leaves and stems were identified; whereas, normal plants maintained their green-colored leaves and stems. The highest frequency of variation (67.5 %), with a mean number of 3.0 variant shoots per explants, was obtained on shoot proliferation medium (MS + 2.0 mg L-1 BA and 0.5 mg L-1 NAA) devoid of NH4NO3. The best rooting (100 %), with the highest number of roots per shoot (10.8) and the greatest root length (6.8 cm) was obtained on medium supplemented with 0.1 mg L-1 NAA. In vitro-grown plantlets were successfully acclimatized in a greenhouse, and transferred to the field.