Effects of carbon source and concentration on development of lingonberry (<Emphasis Type="Italic">Vaccinium vitis-idaea</Emphasis> L.) shoots cultivated <Emphasis Type="Italic">in vitro</Emphasis> from nodal explants

Summary Carbohydrate type and concentration and their interactive effects on in vitro shoot proliferation of three lingonberry (Vaccinium vitis-idaea ssp. vitis-idaea L.) cultivars (‘Regal’, ‘Splendor’, and ‘Erntedank’) and two V. vitis-idaea ssp. minus (Lodd) clones (‘NL1’ and ‘NL2’) were studied. Nodal explants were grown in vitro on medium with 2 μM zeatin and either glucose, sorbitol, or sucrose at a concentration of 0, 10, 20, or 30 gl⁻¹. The interactive effects of carbohydrate type and concentration and genotype were important for shoot proliferation. The best response was afforded by sucrose at 20 gl⁻¹ both in terms of explant response and shoot developing potential, although glucose supported shoot growth equally well, and in ‘NL1’ at 10 gl⁻¹ it resulted in better in vitro growth than sucrose. Carbohydrate concentration had little effect on shoot vigor. The genotypes differed in terms of shoots per explant, length, and vigor, leaves per shoot, and callus formation at the base of explants; this was manifested with various types and concentrations of carbohydrate. Changing the positioning of explants on the medium from vertically upright to horizontal increased the shoot and callus size, but decreased shoot height and leaves per shoot. Proliferated shoots were rooted on a peat:perlite (1∶1, v/v) medium and the plantlets were acclimatized and eventually established in the greenhouse.