ISHS Acta Horticulturae 547: III International Symposium on Rose Research and Cultivation
CUT ROSE FLOWER LONGEVITY AND ITS VARIATION BETWEEN PLANTS OF CV. FRISCO GROWN IN DIFFERENT LIGHTING PERIODS |
| Authors: | L.E. Särrkä, H.J. Rita, S.O. Ripatti |
| Keywords: | Rosa x hybrida, vase life, survival models, supplementary lights |
| Abstract:
An experiment was conducted to compare four light treatments in winter after a rest period with respect to their effects on vase life of roses cv. Frisco. The light treatments were: 20 h d-1 between 01-21 o’clock during 28 days, thereafter 15 h d-1 between 05-20, 20 h d-1 between 01-21, 20 h d-1 between 05-21 and 23-03, and 18 h d-1 between 05-21 and 24-02. The PPFD was 100 µmol m-2 s-1 provided by HPS lamps. The mean vase life lengths were all within a very short range of 9.3-10 days, the light treatment 20 h d-1 / two night breaks having the largest average duration. Despite the small differences between the average durations, survival models revealed that the treatments were different with respect to the hazards, or risks, of ceased ornamental value. The risk was 40 % higher in treatment 20 h d-1 / one night break than in 20 h d-1 / two night breaks. A recent elaboration of survival models was used to estimate the plant level (i.e. within treatment) variation in hazards. The plant hazards varied considerably more than the hazards between the treatments. In addition, the plant level variation in hazards seemed to vary between the treatments. The light treatments with two night breaks had less plant level variation than treatments with one night break. Estimation of plant level hazards makes it possible to identify the most risky and most reliable plants. | |
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