ISHS Acta Horticulturae 580: IV International ISHS Symposium on Artificial Lighting
ESTIMATION OF TOTAL CANOPY PHOTOSYNTHETIC CAPACITY OF ROSES GROWN UNDER TWO CANOPY MANAGEMENT SYSTEMS |
| Authors: | R.M. Warner, J.E. Erwin |
| Keywords: | Rosa hybrida, photosynthesis, yield, irradiance, bending, arching |
| Abstract:
Roses (Rosa hybrida L. ‘Kardinal’) grown in a traditional upright production system form dense canopies, resulting in shading of many lower leaves. Recently, many growers have adopted a ‘bent-shoot’ production system where the majority of shoots are bent to create a horizontal canopy, other than the flowering shoots, to increase light availability to the canopy and cut rose quality. The present experiment was conducted to determine the photosynthetic contributions of leaves at various positions throughout the canopy with both production systems and the impact of these differences on yield. Photosynthetic rates of individual leaves at ca. 10 cm vertical intervals were measured. Total leaf number within each vertical interval was determined and used to calculate total Pn for a whole plant under both production systems. Plants managed in the bent-shoot system exhibited a whole plant photosynthetic rate 28.4% higher than plants managed as an upright hedge system. In addition, harvested stems from the bent-shoot system were 50% longer, had larger flowers (14% larger diameter and 44% higher dry mass), and 124% greater total dry mass than stems from the traditional upright system. These data provide a base from which to evaluate alternative canopy management systems. | |
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