<i>In-Vitro</i> Regeneration of <i>Citrus sinensis</i> (L.) Osbeck from Mature Seed Derived Embryogenic Callus on Different Solid Basal Media

In-vitro callus induction and regeneration method was developed using different plant growth regulators (PGRs), and basal media (Murashige and Skoog (MS), CHU (N6) and Gamborg (B5) media) of Citrus sinensis (L.) Osbeck. Observations of the effect of PGRs were carried out using different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D),1-naphthalene acetic acid (NAA) and combinations of 2,4-D and NAA using different basal media. This study found Citrus sinensis (L.) Osbeck exhibited a high frequency of callus induction on MS medium supplemented with 3 mg/L 2,4-D and callus induction frequency was 86.7% ± 3.4% whereas N6 and B5 showed lower callus induction frequency of 83.3% ± 8.8% and 82.2% ± 1.9% respectively compared to that of MS media with supplementation of the same hormone. Among the induced calli, the morphological analysis showed only 40% - 50% was embryogenic calli. Regeneration of plantlets from calli was done using different concentrations and combinations of auxin and cytokinin. The study showed that 3 mg/L 6-benzylaminopurine (BAP) supplemented medium has the maximum potential to promote regeneration of Citrus sinensis (L.) Osbeck from embryogenic calli with the frequency of 89.3% ± 8.8% but no regeneration occurred from the non-embryogenic calli. The regenerated plantlets were rooted on MS medium with supplementation of 5 mg/l NAA. These observations in Citrus sinensis (L.) Osbeck regeneration will be helpful for genetic improvement with desired traits.