effect of genotype, explant type and 2,4-d on cell dedifferentiation and callus induction in cumin (cuminum cyminum) medicinal plant

context : cumin ( cuminum cyminum l.) as a member of the apiaceae family is one of the most important medicinal plants in the world. objective : an experiment was conducted for evaluation of callus induction optimization in cumin accessions (shahdad, koohbanan, badrood and afghanistan). materials and methods : factorial experiment based on completely randomized design (crd) with three replications was conducted on ms medium supplemented with different concentrations of 2,4-d (0, 0.5, 1 and 2 mg/l) plus 0.1 mg/l kinetin in different explants (root, shoot, leaf, embryo and seed) of cumin accessions. in this experiment the evaluated traits include days to callus induction (dci), callus induction percentage (cip) and callus growth rate (cgr). results : statistical analysis showed that seed (as the latest) and root (as the earliest) explants require to 54 and 11 days in order to callus induction initiation respectively. results showed that accession, explant, accession × explant and 2,4-d × explant interactions were statistically significant effects ( p<0.01) on callus induction percentage and callus growth rate traits. furthermore, 2,4-d had a high significant effect on callus induction percentage. conclusion : according to results of this study, root explant is an appropriate explant for large production of callus in some accessions of cuminum cyminum . also, koohbanan accession produced callus in minimum time and afghanistan accession produced high percentage of callus.