Direct and high frequency somatic embryogenesis and plant regeneration from hypocotyls of chickpea (Cicer arietinum L.), a grain legume

Abstract

A protocol for plant regeneration via somatic embryogenesis was developed in two high-yielding chickpea cultivars. Somatic embryos were induced directly from hypocotyl explants on Murashige and Skoog's (MS) medium fortified with different concentrations of 2,4-dichlorophenoxyacetic acid, 2,4,5- trichlorophenoxyacetic acid, naphthaleneacetic acid, picloram and dicamba either singly or in combination with 0.5-2.0 mg l-1 N6- benzylaminopurine or 0.5-2.0 mg l-1 kinetin. Type of auxin, its concentration and genotype influenced the frequency of somatic embryogenesis. Picloram was better for somatic embryo induction compared to other auxins. The well-formed, cotyledonary-shaped embryos germinated into plantlets with 49.6% frequency on MS medium supplemented with 0.5 mg/l abscisic acid and 2.0 mg l-1 benzylaminopurine. The frequency of embryogenesis and subsequent plantlet regeneration was higher in ICCV-10 than in Annigeri. Regenerated plants were transferred to soil and grown to maturity with 80% survival and the tissue culture-raised plants produced viable seeds. This protocol to produce embryos with a high frequency and their subsequent conversion to whole plants offers potential for use in gene transfer and development of transgenics in this important grain legume and also for the production of synthetic seeds.