Effects of Different Amounts and Split Application of Nitrogen on Quantitative and Qualitative Characteristics of Rose Flower cv. Mohandesi (Ilona)

In order to determine the effects of different amounts and split application of nitrogen on the yield and quality indices of rose flower (Rosa hybrida L.) cv. Mohandesi (Ilona) a 4- year factorial trial was conducted at Safi Abad agricultural research center in 2002-2006 as completely randomized block design in three replications. The treatments were as follows: Nitrogen at five rates: 0, 150,300,450 and 600 Kg/ha from urea and split application of nitrogen at three levels: first level: 2/3 of nitrogen after fall pruning + 1/3 in bud formation stage (farmers` conventional methods). Second level: 1/3 of nitrogen after fall pruning + 1/3 in vegetative quick growth + 1/3 in bud formation stage. Third level: 1/4 of nitrogen after fall pruning + 1/4 in vegetative quick growth + 1/4 in bud formation stage + 1/4 in middle of flowering period.The results of combined variance analysis revealed that the main effects on nitrogen rate on number of flowers per plant and flowers number in first and second classes per plant significantly increased at 1% level. But the main effects of split application of nitrogen and interaction effects between nitrogen rates and split levels on mentioned indices did not significant. Also leaf mineral nutrients such as nitrogen, potassium and manganese were affected by the main effects on nitrogen rate. Besides, iron and zinc were affected by the main effects of split application of nitrogen. Furthermore, all rose flower quality indices were affected by main effects of nitrogen rate, but were not affected by main effects of split application of nitrogen and interaction effects between nitrogen rates and split levels. In conclusion application of 150 kg/ha nitrogen from urea in two or three parts (first or second levels of split application) is recommended for production of cut rose flower in north Khuzestan under outdoor condition.