A comparison of genetic stability in tea [Camellia sinensis (L.) Kuntze] plantlets derived from callus with plantlets from long-term in vitro propagation

Morphological variation, genotypic stability and genetic distances among micropropagated tea [ Camellia sinensis (L.) Kuntze] cv. ‘Kolkhida’ plantlets after 7 years of propagation in vitro and among plantlets regenerated from callus were compared. Fifteen individuals, randomly chosen amongst a set of 100 plantlets regenerated from callus, and ten individuals, randomly chosen from a set of 100 micropropagated plants were used in the study. Morphological descriptors showed higher variability among callus-derived regenerants than in micropropagated plants. Flow cytometry analysis showed no significant variability of nuclear DNA content among micropropagated plants, however changes in DNA indicated aneuploidy in three out of ten callus-derived regenerants. ISSR analysis showed lesser genetic distances among micropropagated plantlets and maternal cultivar ‘Kolkhida’ compared with callus derived plantlets. Yet, there is some degree of genetic instability after long-term micropropagation. Results confirmed the hypothesis of genetic instability of some species during long term in vitro conservation. Key message Tea vegetative explants plants were propagated in vitro for 7 years. A comparison of tea plantlets derived from callus with plantlets from long-term in vitro propagation revealed genetic variability and confirmed the hypothesis of genotype instability of tea plant.