In vitro culture establishment and shoot multiplication of eight autochthonous plum genotypes

Autochthonous plum genotypes have immeasurable genetic and cultural value in Serbia. The paper deals with initial steps for establishment of an efficient protocol for micropropagation of selected eight autochthonous plum genotypes. The clonal selection has been carried out within cultivars ‘Crvena Ranka’ (six genotypes), ‘Crnošljiva’ (one genotype) and ‘Metlaš’ (one genotype) originated from heterogeneous local populations in western Serbia. Two surface-sterilizing procedures containing sodium hypochlorite or mercuric chloride as the main sterilizing agents, were tested for establishment of aseptic cultures. Single-node cuttings were cultured on Murashige and Skoog (MS) medium containing 2 mg L^‑1 BA, 0.5 mg L^‑1 IBA and 0.1 mg L^‑1 GA₃ for rosette initiation. After four weeks of culture, frequency of explants with and without developed leaf rosettes and as well as contaminated and necrotic explants after each sterilization procedure were recorded. Significantly better results for contamination control and rosette initiation were achieved when surface sterilization was done with mercuric chloride in comparison to sodium hypochlorite in all genotypes, except ‘Metlaš’. All genotypes can be successfully multiplied for at least five subcultures on MS medium with 1 mg L^‑1 BA, 0.1 mg L^‑1 NAA and 0.1 mg L^‑1 GA₃. For most of the genotypes, constant increase in shoot formation capacity was observed over repeated subculturing. Further research is necessary to evaluate rooting and acclimatization stages in the micropropagation protocol of selected genotypes.