Effect of two irrigation frequencies on rose flower production and quality
A better understanding of the effects of irrigation frequency on flower production and quality of rose plants can help to develop optimal irrigation systems. On this purpose experiments were conducted on a soilless rose crop (Rosa hybrida, cv. First Red) grown in a closed hydroponic system, in a greenhouse located on Eastern Greece. In order to study the effect of high and low irrigation frequency on rose crop flower production and quality, measurements of cut-flower fresh and dry weight, number of harvested flowers and flowering stem length, as well as measurements of microclimate variables were carried out. Irrigation scheduling was based on crop transpiration and irrigation was performed whenever accumulative solar radiation outside the greenhouse reached 470 kJ m-2 (high irrigation frequency) or 940 kJ m-2 (low irrigation frequency). The amount of water applied was 0.2 mm and 0.4 mm for high and low irrigation frequency, respectively. The results showed that irrigation frequency affected cut flower fresh and dry weight since the total values of cut flower fresh and dry weight measured at the end of the experimental period were 413 and 310 g m-2 for high and 120 and 89 g m-2 for low irrigation frequency, respectively. As far as the number of cut flowers is concerned, the results showed that the higher the irrigation frequency, the higher the production, since the total number of cut flowers measured at the end of the experimental period was 20.7 and 16.2 flowers per greenhouse m-2 for high and low irrigation frequencies, respectively. Finally, the results showed that the quality of rose flowering shoots was not affected by the irrigation frequency. In conclusion, it seems that the higher irrigation frequency improved the biomass production but did not affect the quality of harvested flowers.