In-vitro propagation of citrus: Protocol development for regeneration and multiple shoot induction from nodal segments

Abstract

The citrus industry represents a vital segment of the global fruit sector owing to its significant nutritional profile and the commercial value derived from both fresh produce and processed products. Micropropagation has emerged as an efficient approach for the large-scale production of genetically uniform citrus plants, overcoming limitations associated with conventional propagation methods. In this study, a protocol was developed for the direct induction of multiple shoots from nodal segments of Citrus reticulata (Kinnow mandarin) and Citrus sinensis (Mosambi). Explants were cultured on Murashige and Skoog (MS) medium enriched with varying concentrations and combinations of cytokinin and auxins. Among the tested formulations, MS medium supplemented with 3 mg/L 6-benzylaminopurine (BAP) and 0.5 mg/L α-naphthalene acetic acid (NAA) yielded superior results in both cultivars, producing the shortest duration to shoot initiation (14.66 days in Kinnow and 15.33 days in Mosambi), the highest percentage of responsive explants (95.55% and 96.22%), the greatest number of shoots per explant (5.44 and 5.55), and the maximum shoot length (4.00 cm and 3.90 cm). Furthermore, the incorporation of BAP (1 mg/L), kinetin (KIN, 0.5 mg/L), and NAA (0.5 mg/L) into MS medium resulted in the greatest leaf production per shoot, with 5.22 leaves in Kinnow and 5.33 leaves in Mosambi.