Researchers from the Plant Physiology and Biochemistry at the Agricultural University in Plovdiv, Bulgaria, assessed the effect of meta-Topolin (MT), an aromatic natural cytokinin, on the micropropagation of pear rootstock OHF-333 (Pyrus сommunis L.).
Clone OHF-333 is a rootstock part of the US OHF series, which are obtained by the Old Home x Farmingdale crossbreed. It has good compatibility with most cultivars, high yields and a moderate resistance to fire blight.
Micropropagated cultures were incubated in a growth chamber at 22±2°С and 16/8 hours of photoperiod. The in vitro culture was maintained on a Murashige and Skoog medium supplemented with various concentrations of meta-Topolin (0, 3, 6, 9 or 12 micromoles). After three weeks, growth parameters and physiological and biochemical aspects were assessed.
It emerged that the absence of meta-Topolin does not provide a practical solution for an efficient multiplication of pear rootstocks.
In vitro multiplication of pear rootstocks OHF-333 on a medium supplemented with various concentrations of meta-Topolin (mT).
A good multiplication rate and high-quality shoots were observed on plants grown with 6 and 9 mT micromoles, as they improved leaf gas exchange.
"This study confirmed that a concentration of 6 and 9 meta-Topolin micromoles is excellent to obtain an in vitro multiplication of rootstock OHF-333. In general, cytokinin mT could be used for the micropropagation of other pear genotypes, especially in case of rooting problems."
Source: Natalya Dimitrova, Lilyana Nacheva, Małgorzata Berova, 'Effect of meta-topolin on the shoot multiplication of pear rootstock OHF-333 (Pyrus communis L.)', 2016, Acta Scientiarum Polonorum - Hortorum Cultus, Vol. 15(2), pag. 43-53