Micropropagation of lingonberry: Influence of genotype, explant orientation, and overcoming TDZ-induced inhibition of shoot elongation using zeatin

Abstract

In an attempt to improve the micropropagation protocol for lingonberry (Vaccinium vitis-idaea L.) developed at the Centre, two lingonberry clones were compared for in vitro shoot proliferation on two different media supplemented with varying levels of thidiazuron (TDZ). TDZ supported proliferation at low concentrations (0.1 to 1 μM) but inhibited shoot elongation. However, usable shoots were obtained within 4 weeks by transferring shoot cluster to medium containing 1 μM zeatin. Genotypes differed significantly with respect to multiplication rate with 'EL1' producing the most shoots per explant. In both genotypes, shoot proliferation was greatly influenced by explant orientation. Changing the orientation of explants from vertically upright to horizontal increased axillary shoot number, but decreased shoot height and leaf number per shoot. Proliferated shoots were rooted on a 2 peat:1 perlite (v/v) medium, and the plantlets were acclimatized and eventually established in the greenhouse.