In vitro callus induction and regeneration of multiple shoots through callus derived from leaf and epicotyl explants in pigeon pea (Cajanus cajan L.)

Abstract

An efficient in vitro protocol was developed for callus induction, high frequency plant regeneration through callus cultures derived from cotyledonary leaf and epicotyl explants, rooting of shoots derived from callus and establishment onto the natural conditions in two cultivars of pigeon pea; ICPL 87119 and ICPL 8863. Cotyledonary leaf and epicotyl explants were tested for callus induction across 48 different combinations and concentrations of auxins and cytokinins in MS medium, wherein, higher doses of auxins (15 mg/1 NAA) in combination with lower doses of cytokinins (0.5 mg/l kinetin) induced regenerable callus from leaf explants while lower doses of auxins (0.2 mg/1 NAA) in combination with higher doses of cytokinins (8 mg/1 kinetin) induced regenerable callus from epicotyl explants in both the genotypes. Plantlet regeneration from leaf and epicotyl derived callus was optimized at 0.05 mg/l TDZ in both genotypes. Rooting was optimized on ½ MS + 0.5 mg/1 IBA media in both genotypes. Well-rooted plants were acclimatized and established successfully into natural conditions in potting mixture-containing soil: FYM in 1:1 ratio resulting in 48.01 per cent survivability. Regenerated plants were uniform morphologically with normal leaf shape and growth. This protocol finds its significance in rapid multiplication of transgenic plants.