Regeneration of a Tetraploid Clone from Callus Culture of Asparagus officinalis L. through Somatic Embryogenesis

Abstract

A tetraploid callus line of Asparagus officinalis L. was identified from 4 regenerated callus lines. Plants were regenerated from these callus lines following somatic embryogenesis and the tetraploid clone of this species was established in the field with 80% survival rate. The embryogenic callus was induced in Murashige and Skoog's (MS) medium in presence of α- naphthaleneacetic acid (NAA) (0.2 mg/l) and kinetin (0.02 mg/l) and proliferated as well as maintained in 2,4-dichlorophenoxyacetic acid (2,4-D) (1.0 mg/l) containing MS medium. Somatic embryos were initiated in Gelrite-solidified MS medium with variable levels of NAA and 6-(γ-γ-dimethylallylamino) purine (2ip). A higher level of carbohydrate enhanced embryo conversion efficiency. The embryos induced in presence of 10% glucose for 2 weeks and subsequently transferred to 2% sucrose level showed higher conversion rate than those maintained in 3% sucrose concentration. Karyotype analysis of diploid and tetraploid clones revealed exact duplication of the diploid set in tetraploid plants.