Advances in in vitro clonal propagation and tuber formation of Solanum tuberosum “Agata” through sequential hormonal treatments

Solanum tuberosum (potato) is the third most important food crop in the world. It is anautopolyploid heterozygous crop with high inbreeding depression. Potato tubers are used inbiotechnology for crop enhancement because their buds easily adapt to in-vitro culture. Potato isprone to biotic stress, including soil and tuber-borne diseases. Biotechnological approachesimprove potato output and quality for disease eradication and for reducing inbreeding depression.Clonal propagation by in vitro culture preserves heterozygosity in interesting cultivars, including“Agata”. Exogenously applied benzyl-adenine (BAP) and indole-3-butyric acid (IBA) favor differentphases of the sprouting-to-tuberization process, but a role for exogenous brassinosteroids(24-epibrassinolide, eBL) has been also suggested. Using sequential applications of BAP, IBA, andeBL, at specific concentrations, the process from bud-sprouting to tuberization was morphologically/cyto-histologically analyzed. Tuber-bud sprouting was favored by 9 μM BAP and the subsequentapplication of eBL (0.1 µM) to stem mini cuttings favored shoot elongation, whereas that of IBA(1 µM) increased rhizogenesis. Tuberization occurred during ex vitro acclimation. Tubermicrobiological analyses verified the absence of contamination due to pathogenic microorganisms.Altogether results represent a biotechnology advancement in cell culture applications of potatoand show a method for producing healthy plants while maintaining their heterozygous features.