A mono-phasic protocol for micropropagation of potato cv. Cooch Behar local, its acclimatization, on-field evaluation, and fidelity analysis.

A protocol for micropropagation of potato (Solanum tuberosum L.) cv. Cooch Behar local retaining the fidelity of the in vitro regenerants was established for the first time. Initially, tuber sprouts were inoculated in Murashige and Skoog (MS) basal medium supplemented with 0.5-1.5 mg/l 6-benzyladenine (BA), kinetin (Kin), meta-Topolin (mT), and zeatin (Zea). A maximum number of shoots was induced in 0.5 mg/l Zea followed by 0.5 mg/l mT. For subsequent rooting, the shoots were inoculated in MS medium supplemented with 1.0-3.0 mg/l indole-3-acetic acid and indole-3-butyric acid (IBA), wherein 1.0 mg/l IBA-fortified medium recorded the maximum number of roots. The mono-phasic micropropagation, i.e., simultaneous multiple shoots and roots formation was achieved in MS medium with combinations of Zea (0.25-1.0 mg/l) with 1.0 mg/l IBA, wherein 0.5 mg/l Zea + 1.0 mg/l IBA exhibited the best results. The micropropagated plantlets were then acclimatized in cocopeat with 100% survival before field evaluation. To ensure the true-to-type nature of the micropropagated plants, the cytology, flow cytometry, inter simple sequence repeats (ISSR), and start codon targeted (SCoT) polymorphism primers based fidelity analyses were carried out. Cytology and flow cytometry confirmed that the micropropagated plants had the same ploidy levels. Likewise, the molecular marker-based genetic fidelity study via ISSR and SCoT primers showed monomorphic banding patterns. The present protocol has the potential for large-scale propagation, conservation, and commercialization of indigenous potatoes and can also be used to study the response of other potato cultivars to in vitro regeneration.