Effect of sources and concentrations of folliar application of potassium on the yield and quality of gerbera (Gerbera jamesonii cv. Stanza)

Effects of foliar application of potassium sources and their concentrations on the yield and quality of hydroponically grown cut flower Gerbera jamesonii cv. Stanza was studied. The experiment was carried out at Pakdasht, Varamin, in 2008. Plants were either sprayed with three salts included KNO3, K2SiO3 and K2SO4 with a net potassium concentration of 0, 1.5 and 3 g/l respectively. The treatments were conducted as a complete randomized design with five replicates. The resultes indicated that all K treatments increased the yield significantly at 1% of probability level. The treatment KNO3 showed the highest yield. The quality of the gerberas was significantly improved in KNO3 and K2SiO3 treatments (3g/l) as compared with the control. An increase of potassium concentration in all cases, rised amount of leaf potassium content in plants. A significant increase of chlorophyll ratio was observed in all potassium treatments as compared with the control. In turn, cocentrations of Ca and Mg elements were reduced in all plants treated with potassium treatments. Level of potassium has been increased in foliage parts without any side effects on plant quality. By mean comparisons, it is concluded that the foliar application of potassium nitrare and potassium silicate (3g/l) disclosed high advatages on the growth and quality of cut flower gerbera.