An effective protocol for improved regeneration capacity of Kabuli chickpeas

Abstract

An efficient protocol for in vitro regeneration is essential for genetic manipulation and micropropagation of important plant species. A direct shoot regeneration system has been optimized for Desi chickpeas, but an effective regeneration protocol is still needed for Kabuli chickpeas. An efficient regeneration protocol for Kabuli chickpeas was developed, using whole embryonic axes, an embryonic axes slice and cotyledonary node explants from two genotypes L550 and JGK-1. Depending upon chickpea genotype, type of explant and culture medium, percentage of shoot producing explants (frequency) and the number of shoots per explant (efficiency) varied from 10 to 83% and from 1 to 58, respectively. The shoot regeneration capacity (SRC=frequency×efficiency), which is an indicator of the effectiveness of the protocol, varied from 47 to 2508 shoots per 100 explants cultured. On average, SRC of L550 was 1.8 times higher than JGK-1. Murashige and Skoog's (MS) medium+B5 vitamins supplemented with 8.0 μM benzyl amino purine (BAP)+0.5 μM α- naphthalene acetic acid (NAA) and 0.1 M sucrose plus embryonic axes was found to be the most effective culture medium and type of explants, respectively. Half strength MS medium+2% sucrose supplemented with 4 μM NAA, 3 μM IAA or 4 μM IAA produced a high rooting percentage in both chickpea genotypes. The regeneration process starting from explant preparation to establishment of a complete plant in soil took 105-110 d. This optimized regeneration method holds promise for facilitating the insertion of interested genes through genetic transformation for improvement of Kabuli chickpeas.