Somatic embryogenesis and plant regeneration of Capsicum baccatum L

Abstract

A plant regeneration protocol via somatic embryogenesis was achieved in cotyledon and leaf explants of Capsicum baccatum, when cultured on MS medium supplemented with various concentrations of 2,4-dichlorophenoxy acetic acid (2,4-D, 0.5-5.0 mg l^-1) in combination with Kinetin (Kn, 0.5 mg l^-1) and 3% sucrose. Various stages were observed during the development of somatic embryos, including globular, heart, and torpedo-stages. Torpedo stage embryos were separated from the explants and subcultured on medium supplemented with various concentrations of different plant growth regulators for maturation. Maximum percentage (55%) of somatic embryo germination and plantlet formation was found at 1.0 mg l^-1 BA. Finally, about 68% of plantlets were successfully established under field conditions. The regenerated plants were morphologically normal, fertile and able to set viable seeds.

Keywords: 2,4,5-T, 2,4,5-trichlorophenoxy acetic acid; 2,4-D, 2,4-dichlorophenoxyacetic acid; BA, 6-benzyl adenine; Cotyledon; GA3, Gibberellic acid; IAA, indole-3-acetic acid; Kn, kinetin; Leaf; MS, Murashige and Skoog (1962) medium; NAA, α-naphthalene acetic acid; Pepper; Picloram, 4-amino-3,5,6-tri chloropicolinic acid; Somatic embryos; TDZ, thidiazuron.

Figure 1

Different developmental stages of direct somatic embryogenesis and plant regeneration in Capsicum baccatum. (a) Globular embryos developing directly from cotyledon explants (b) isolated single globular stage embryo (c) cluster of various developmental stages somatic embryos (d) cotyledonary stage of somatic embryo (unequal cotyledons) (e) dicotyledonary stage of somatic embryo.

Figure 2

Acclimatization and hardening of Capsicum baccatum L. plants derived from somatic embryos. (a) Potted plantlets after 3 weeks, (b) complete plant with normal fruits.