ISHS Acta Horticulturae 751: IV International Symposium on Rose Research and Cultivation
DEVELOPMENT OF A PHASE DEPENDENT GROWTH STRATEGY FOR MOBILE ROSE CULTIVATION SYSTEMS |
| Authors: | N. García Victoria, B. Eveleens, H.J. Van Telgen |
| Keywords: | bud break phase, exponential growth phase, ripening phase, temperature, degree-days, Y-bush |
| Abstract:
Nowadays, movable benches are a reality in rose cultivation in The Netherlands. They allow a better use of the greenhouse surface and they reduce labour by bringing all the plants to a central working area in which the crop maintenance and harvest are carried out. The existing systems are all based on traditional plant cultivation systems. Since in this system, each plant potentially can have a harvestable stem, this means that every day all the plants must be brought to the central working station. Mobility also offers many new opportunities to break with the traditional cultivation systems. It can be envisaged that the greenhouse is organized in such a way that plants are synchronized and grouped according to the developmental stage of the stems, thus avoiding the presence of different developmental stages in one plant. In such a system, only those plants that actually hold a harvestable stem would need to be transported to the working station, whereas all other plants can stay in a steady place for the remaining part of the growth cycle. This would reduce the number of movements in the greenhouse already by two thirds. Moreover, a spatial separation of the groups in a similar developmental stage would allow specific climatic conditions for each group and provide tools to direct production towards specific harvest dates. To study the effects of light, temperature, CO2, EC and VPD on each of three distinguished development stages of a rose stem, tests were performed with synchronized Y-bushes of the rose cv. ‘First Red’. The hypothesis that the different phases are sensitive to different climatic conditions was confirmed. The duration of the bud break phase and early shoot growth turned out to be fully dependent on temperature and was completed after ±200 degree-days for this cultivar. The high correlation between the shoot length at the end of this phase and the time required to reach the visible bud stage, makes the shoot length a good parameter for sorting of plants to obtain more uniform groups. The light intensity turned out to play a limited role in this phase. The phase of exponential growth until visible bud is also very much directed by temperature. Under non-limiting light conditions it is completed after ±480 degree-days; more degree-days are necessary to complete this phase below a critical day light sum of 11 mol/m2/day. When this level was not reached (in the period November to February), some bud abortion was observed in this phase. The ripening phase was found to be strongly dependent of light: a higher intensity of supplementary light in this phase significantly shortened the number of degree-days required to complete this phase, and increased the stem weight. | |
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