meta-Topolin-induced in vitro propagation, field evaluation, flow cytometry and molecular marker-based genetic stability assessment of potato cv. Badami alu

Potato (Solanum tuberosum L.), belonging to Solanaceae family, globally ranks as the fourth-largest food (vegetable) crop. In order to sustain the supply of quality propagules, a large-scale in vitro shoot, microtuber and root development protocol was successfully established for potato cv. Badami alu, for the first time. Initially, the tuber sprout explants were inoculated in Murashige and Skoog (MS) basal medium individually with 0.5–1.5 mg/l 6-benzyladenine, kinetin, meta-topolin (mT) and zeatin (Zea) for regeneration. The earliest (~ 3 days) shoot initiation with maximum number (~ 9) and length (81 mm) shoots were recorded in MS medium fortified with 1 mg/l mT after 4 weeks of growth period. The earliest (44 days) microtuber formation with maximum number (4.3) was recorded in MS medium fortified with 1 mg/l Zea after 8 weeks growth stage. On the other hand, the hierarchical clustering heat map, network plot, and principal component analyses illustrated the association among cytokinins (sources and concentrations) and the different growth attributes under study. In vitro-regenerated shootlets were then cultured in MS medium individually with 1–3 mg/l indole-3-acetic acid (IAA) and indole-3-butyric acid. The earliest (~ 7 days) root induction was recorded in MS medium with 1 mg/l IAA, whereas the maximum number (47) with most elongated (28.3 mm) roots were recorded in 2 mg/l IAA after 4 weeks culture period. The micropropagated plantlets were grown in cocopeat (for 1 month) followed by soil (for 2 months) under field conditions (shade net house) that resulted in 95% survival rate. Stability of ploidy level of micropropagated and successively field-grown plantlets with their mother plant was affirmed by flow cytometry, likewise, genetic fidelity was assessed for the same via inter simple sequence repeats, directed amplification of minisatellite-region DNA, start codon targeted polymorphism, and conserved DNA-derived polymorphism markers, and a 100% monomorphism was found, proving that there was no genetic variation among them. Since there is no report of non-conventional mass propagation of this cultivar to date, the present protocol will be immensely helpful for its accelerated large-scale propagation and its genetic improvement.