| Abstrakt: |
ABSTRACTThe aim of this research was to test the commercial value of highly productive rose rootstocks obtained by transformation with rol A, B, C genes from Agrobacterium rhizogenes. The production of flowering stems depends on the number of axillary shoots or basal shoots. Axillary bud release is a process which is controlled by plant hormones such as auxins and cytokinins. Rol A, B, C genes are known to interfere with hormone metabolism and root development. Therefore, these genes were chosen for the introduction into rootstock cultivar ‘Moneyway’ by transformation. Nontransformed scions from cultivars Vivaldi, Madelon and First Red were grafted upon these transgenic rootstocks. From October 1998 to April 2000, we measured the effect of the transgenes on rose production in a large-scale greenhouse experiment. The transgenic rootstocks outproduced—in number of stems- the untransformed controls by 19 %. The total fresh weight increased by 6% only, resulting in a decrease in weight per stem by 11 %. The production increase is mainly explained by an increase of the number of new axillary buds at the base of the stem after cutting. To comply with the demand for energy-efficiency, the greenhouse was kept at a low temperature in winter. The increase in yield was, however, also observed in the summer when the temperature in the greenhouse was relatively high. |
