An efficient and reliable protocol on in vitro propagation of ‘Colt’ (Prunus avium F 299/2 x Prunus pseudocerasus Lind.) rootstock of cherry

Abstract: The ‘Colt’ is a triploid hybrid of P. avium and P. pseudocerasus L. grown as a cherry rootstock because of its resistance to cherry stem pitting (a debilitating virus disease), Phytophthora root rot, bacterial canker and gopher damage. The current study was carried out using two types of explants: forced (F₁) and unforced (F₂) shoots tips. Five types of sterilants were used to sterilize explants: 10% sodium hypochlorite (NaOCl) for 10 minutes (S1), 0.1% mercuric chloride (HgCl₂) for 5 minutes (S2), ethyl alcohol for 10 seconds (S3), (S1) + (S3) and (S2) + (S3). During culture establishment, six growth regulator regimes viz., BA (benzyl adenine) (0.20), (0.40) and (0.60) and BA+IBA (Indole-3-butyric acid) (0.20+0.01), (0.40+0.01), and (0.60+0.01) mg/L, two media i.e., MS (Murashige and Skoog, 1962) and WPM (Woody Plant Medium) were utilized. During shoot proliferation, MS & WPM culture medium with growth regulators viz., BA (0.20), (0.40) and (0.60), BA+IBA (0.20+0.01), (0.40+0.01) and (0.60+0.01) mg/L were used respectively. During rhizogenesis in different media (MS & WPM), various levels of IBA (0.50, 1.00, 1.50 and 2.00 mg/L) were used. The superior rooted plants were hardened in sand & cocopeat, respectively. In this experiment, maximum culture asepsis (%) obtained in unforced shoot tips(F₂) with (S₅), maximum explant survival (%) in forced shoot tips (F₁) with (S₄), and highest establishment (%) with MS medium, BA (0.6) mg/L & in forced shoot tips (F₁). Significantly higher shoot proliferation is obtained with MS medium with BA (0.6) mg/L, maximum shoot number & length in WPM medium with BA (0.2) mg/L. A significantly higher rooting percentage was obtained in an MS medium with IBA (1.00) mg/L and maximum ex vitro survival (%) in cocopeat.