Effect of Nitrogen forms (NH4 and No3) in nutrient solution on Qualitative and Quantitative characteristics of two varieties of Gerbera (Gerbera jamesonii)

This experiment was performed to evaluate the effect of N form (ammonium and nitrate) on the growth and physiological characteristics of two gerbera flowers cultivars (‘Stanza’ and ‘Double Dutch’) to recommend the appropriate amount of NH4+:NO3¯ ratio in the nutrient solution to achieve optimum gerbera yield and quality. This experiment was conducted as a factorial in completely randomized design with two factors including NH4+:NO3¯ ratios and cultivar with three replications. The NH4+:NO3¯ ratios (0:100, 20:80, 40:60, and 60:40) were supplied as a first factor. The second factor included cut gerbera cultivars (‘Stanza’ and ‘Double Dutch’). The results indicated that increasing ammonium concentration in the nutrient solution to more than 40% of total N, significantly reduced growth indices and gerbera flowers number compared to NH4+:NO3¯ ratio of 20/80. The highest number of flowers (314 flowers m-2 year-1), stalk fresh weight (36.1 g), flower stalk diameter (0.92 cm), flower disk diameter (12.3 cm), and vase life (14 days) were obtained in 20/80 of NH4+:NO3¯ ratio. Results indicated that nutrient solution with NH4+:NO3¯ ratio of 20/80 is an appropriate solution recommended for commercial production of gerbera cut flowers in order to achieve the highest growth and quality.Key Words: ammonium, Double Dutch, flowers number, Stanza,vase life