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- Author or Editor: Samir C. Debnath x
In an attempt to improve the micropropagation protocol for lowbush blueberry (Vaccinium angustifolium Ait.), a protocol using a bioreactor system combined with a semisolid gelled medium has been developed. Cultures of cultivar Fundy and two wild clones (‘NB1’ and ‘QB1’) were established in vitro on a gelled modified cranberry basal medium (BM) containing 5 μM zeatin or 10 μM N6-[2-isopentenyl]adenine. Multiple shoots were obtained within 8 weeks by transferring zeatin-induced shoots from the gelled BM to a bioreactor containing liquid BM with 1 to 4 μM zeatin. Genotypes differed significantly with respect to multiplication rate in liquid and gelled BM containing 1 μM zeatin with ‘NB1’ producing 8.5 ± 1.1 and 2.9 ± 0.3 shoots per explant in liquid and gelled media, respectively, after one subculture followed by ‘QB1’ (7.1 ± 0.6 and 2.6 ± 0.4 shoots per explant, respectively) and ‘Fundy’ (5.8 ± 0.4 and 2.0 ± 0.2 shoots per explant, respectively). With subculture, there was an increase of shoot multiplication rate for all genotypes. Bioreactor- and gelled medium-proliferated shoots were treated with 39.4 mm indole-3-butyric acid powder, rooted in a 2 peat:1 perlite (v/v) medium, plantlets acclimatized, and eventually established in the greenhouse with 64% to 74% rooting of microshoots and 90% to 99% survival of rooted shoots. Results obtained suggested the possibility of large-scale multiplication of lowbush blueberry shoots in bioreactors.
The growth and development of lingonberry (Vaccinium vitis-idaea L.) plants propagated either by conventional softwood cuttings or by in vitro shoot proliferation from nodal explants and by shoot regeneration from excised leaves of micropropagated shoots, were studied in cultivars `Regal', `Splendor', and `Erntedank'. Significant differences were observed between the treatments. After 3 years of growth, the in vitro-derived plants produced more stems, leaves, and rhizomes than the conventional cuttings which rarely produced rhizomes. In vitro culture on nutrient medium apparently induces the juvenile branching characteristics that favor rhizome production. This increase in vegetative growth and rhizome yield of in vitro-derived plants over stem cuttings varied among genotypes.
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.
The effects of TDZ (0, 0.1, 1, 5 and 10 μm) and explant orientation on adventitious shoot regeneration of `Erntedank' lingonberry were studied. Moderate concentration (1 to 5 μm) of TDZ supported bud and shoot regeneration, but strongly inhibited shoot elongation. TDZ initiated cultures were transferred to medium containing 1-2 μm zeatin and produced usable shoots after one additional subculture. Adventitious bud and shoot regeneration was greatly influenced by explant orientation. Elongated shoots were rooted on a 2 peat: 1 perlite (v/v) medium, and the plantlets were acclimatized and eventually established in the greenhouse with 80% to 90% survival rate.
A plant regeneration protocol was developed for cascade huckleberry (Vaccinium deliciosum), mountain huckleberry (V. membranaceum), and oval-leaf bilberry (V. ovalifolium) clones. The effects of zeatin concentrations (0, 4.6, 9.1, and 13.7 μM) and explant type (leaf or stem segment) on adventitious shoot regeneration were studied on a nutrient medium of low ionic concentration. Adventitious bud and shoot regeneration was greatly influenced by clone, explant type, and zeatin concentration. Zeatin at 9.1 to 13.7 μM supported the best bud and shoot regeneration. At low concentrations (2.3 to 4.6 μM), zeatin enhanced shoot elongation and produced usable shoots after one additional subculture. The three clones differed significantly with respect to multiplication rate of adventitious shoots. Oval-leaf bilberry and mountain huckleberry clones produced six to seven 5-cm-long shoots per explant and cascade huckleberry clone produced five 3-cm-long shoots per explant, when 2.3 μM zeatin was used in the medium. Increasing the concentration of zeatin in the culture medium increased shoot number per explant, but decreased shoot height, leaf number per shoot, and shoot vigor. Proliferated shoots were rooted on the same medium but without any plant growth regulators (PGRs). Rooted plantlets were transferred to a 2 peat:1 perlite (v/v) medium for acclimatization and eventually established in the greenhouse with 75% to 90% survival rate. This in vitro protocol will be useful for micropropagation, in vitro selection, and genetic manipulation of Vaccinium species.
The berry morphology (size and weight), phytochemical content (polyphenols, flavonoids, anthocyanins, and proanthocyanidins), and antioxidant activity of lowbush blueberry (Vaccinium angustifolium Ait.) wild clone QB 9C and cultivar Fundy, propagated by tissue culture (TC) and softwood cutting (SC), were studied over two growing seasons to evaluate the effect of propagation methods on fruit yield and the content of antioxidant metabolites. Number of flower clusters, number of berries and berry weight per plant, diameter and weight of individual berry were higher in SC plants than those of TC plants. Significant interaction between genotypes and propagation methods were observed for total phenolic and flavonoid content of fruits. Berries from TC plants contained more polyphenols and flavonoids than those of SC plants. Twenty microsatellite markers were used to assess the clonal fidelity of TC regenerants and SC plants. The identical monomorphic amplification profiles within the TC plants of each genotype confirmed the clonal fidelity of micropropagated blueberry plants. These results indicate that propagation methods affected the morphology and antioxidant metabolites but maintained trueness-to-type genetic makeup in blueberry.