The effect of two times rejuvenation pruning on vegetative and reproductive of four cut rose (Rosa hybrida L.) cultivars under soilless culture

After 4 to 5 years of cultivation of cut roses in greenhouses, flower quality and yield reduced gradually. Therefore, in order to use longer and increase the quality of flowers, the rose bushes need to rejuvenation and pruning. This research was conducted to compare two pruning time (fall= December and winter= March) in 2005- 2006 on four Rosa hybrida L. cultivars in one of the greenhouses with soilless culture in Mahalat provenance. The grafted 5 year bushes were pruned in December and March, 2005 so that, on each plant, three stems were left each with 5 nodes (buds). The plants pruned in December and March flowered in February, 2005 and May, 2006 respectively, when the data recording was carried out. The fresh weight, length, leaf number, leaflet number, diameter and internode length of flower stems; diameter, length, fresh and dry weights of flowers and also leaf chlorophyll content and quality index were measured. Results indicated that, all the cultivars were superior for most of the parameters studied when pruned in winter (March) compared to fall (December). Therefore, in cut roses after 5 years it is better that rejuvenation pruning be done in winter (March) although, since rose plants are highly heterozygous, further researches on other cultivar may be suggested.