Shading Impact on Qualitative Characteristics and Chlorophyll Content of Cut Rose (Rosa hybrida cv. Avalanche)

Light intensity is considered a limiting factor in greenhouse rose production. The main aim of this experiment was to evaluate the effect of shading treatments (0, 25, 50, and 65% shading) on quality and chlorophyll content of cut rose (Rosa hybrida cv. Avalanche), under greenhouse conditions. The experiment was planned in randomized completely block design with four replications. All shoots were bent downwards from above the second bud after removing the young flower bud. Shading significantly affected on bud sprouting, flowering stem fresh and dry weight and flowering stem diameter, so that earliest bud sprouting, highest flowering stem, fresh and dry weight and flowering stem diameter were observed in no shading treatment. However, shading had no significant effect on flowering stem length and leaf area, but specific leaf area increased with shading percentage increment at 65% shade. Results of total chlorophyll content as well as chlorophyll a and b showed a decrement with increasing of shading percentage. In general, shading could be a cause of low-quality in cut roses; therefore greenhouse roses growers should consider greenhouse architecture to maximize light deep penetration.