Document Type : Research Paper



Background and objectives
Proper plant nutrition is very important for high productivity and fruit quality. Strawberry has more need for potassium because this element is a major component of the fruit. Size, colour, and acidity of the fruit have a positive relation with potassium amount. Also, the phenyl phthalamic acid is a regulator that increases the working life of stigma and supports the better pollination, which results in a higher yield. This study was performed to increase the quantity and quality of strawberry fruits.
Materials and Methods
To study the effect of potassium nitrate and phenyl phthalamic acid on vegetative and reproductive growth of strawberry cv. Gaviota, a research was conducted as factorial experiment in a completely randomized design with three replications. Potassium nitrate (0, 1, 2 and 5 g.l-1) and phenyl phthalamic acid (0, 500, 1000 and 1500 mg.l-1) were sprayed on leaves and flowers, respectively. The parameters such as inflorescense and fruit number, yield per plant, fresh and dry weight of fruit, TSS, TA and N, P, K and Ca content of leaf and fruit were measured.
The results showed that the use of 5 g.l-1 of potassium nitrate or 500 mg.l-1 phenyl phthalamic acid had the greatest effect on the fresh and dry weight of fruit. Also, potassium nitrate in concentration of 2 g.l-1 has a significant effect on the number of inflorescences and phosphorus of leaves and fruits. The highest number of fruits (26 fruits per plant) with 2 g.l-1 potassium nitrate and the highest yield per plant (541.2 g) and TSS juice (8.3) with 2 g.l-1 potassium nitrate + 500 mg.l-1 phenyl phthalamic acid were obtained.
The phenyl phthalamic acid could increase fruit setting, which resulted in a yield increase too, especially when it was applied with potassium nitrate. In general, the use of potassium nitrate and phenyl phthalamic acid in concentration of 2 g.l-1 and 500 mg.l-1, respectively, resulted in increase of yield and qualitative and quantitative traits of strawberry.


Main Subjects

Abdollahi, R., Asghari, M.R., and Esmaiili, M. 2010. Effect of nitric oxide and putrescine on quality attributes and storage life of strawberry fruit cv. Selva. Journal of Food Research, 20(1): 177-190. [In Farsi]
Ariza, M.T., Soria, C., Medina-Minguez, J.J., and Martı´nez-Ferri, E. 2012. Incidence of misshapen fruits in strawberry plants grown under tunnels is affected by cultivar, planting date, pollination, and low temperatures. HortScience, 47(11): 1569-1573.
Bolat, I., Guleryuz, M., and Pirlak, L. 1992. Effects of some growing mineral on the growth of strawberry cv Aliso. Bahece, 2(1-2): 55-60.
Cantliffe, D.J., Castellanos, J.Z., and Paranjpe, A.V. 2007. Yield and quality of greenhouse-grown strawberries as affected by nitrogen level in coco coir and pine bark media. Proceedings of the Florida State Horticultural Society, 120: 157-161.
Chow, K.K., Price, T.V., and Honger, B.C. 1992. Nutritional requirements for growth and yield of strawberry in deep flow hydroponic system. Scientia Horticulture, 52: 95-104.
Claussen, W. 1986. Influence of fruit load and environmental factors on nitratereductase activity and concentration of nitrate and carbohydrates in leaves of edggplant (Solanum melongena). Physiologia Plantarum, 67: 73-80.
Davis, J.N. 1964. Effect of nitrogen, phosphorous and potassium fertilizers on the non volatile organic acids of tomato fruit. Journal of the Science of Food and Agriculture, 15: 665-673.
Ehyaei, M. and Behbahani zadeh, A. 1991. Methods of chemical analysis of soil. Soil and Water Research Institute Press. Technical Bulletin, 893 P. [In Farsi]
Eshghi, S., Safizadeh, M.R., Jamali, B., and Sarseifi, M. 2012. Influence of foliar application of volk oil, dormex, gibberellic acid and potassium nitrate on vegetative growth and reproductive characteristics of strawberry cv. ‘Merak’. Journal of Biodiversity and Environmental Sciences, 6(16): 35-38.
Haghighat Afshar, M., Babalar, M., Kashi, A., Ebadi, A., and Asgari, M.A. 2006. The effect of NH4/NO3 ratio on growth and yield of some different strawberry cultivars (Fragaria x ananassa Duch.). Journal of Water and Soil Science, 10(3): 321-335. [In Farsi]
Jaafari Haghighi, M. 2003. Methods of soil analysis, sampling and chemical and physical importance analysis. Nedai-e-Zoha Press. Tehetan, Iran. 236 P. [In Farsi]
Jarosz, Z. and Konopinska, J. 2010. Effect of substrate type and nitrogen fertilization upon yielding and chemical composition of "Elasanta" strawberry cultivar grown in unheated foil tunnel. Acta Scientiarum Polonorum-Hortorum Cultus, 1: 87-96.
Jones, J.B. 2001. Laboratory guide for conducting soil Tests and Plant Analysis. CRC Press. 384 P.
Kaya, C., Kirnak, H., and Higgs, D. 2001. Enhancement of growth and normal growth parameters by foliar application of potassium and phosphorus in tomato cultivar grown at high (NaCl) salinity. Journal of Plant Nutrition, 24(2): 357-367.
Khadivi-Khub, A. and Nosrati, Z. 2013. Study of N-phenyl-phthalamic acid effects on fruit setting and fruit quality of sweet, sour and duke cherries. Acta Agriculturae Serbica, 18(35): 3-9.
Lanauskas, J., Uselis, N., Valiuskaite, A., and Viskelis, P. 2006. Effect of foliar and soil applied fertilizers on strawberry healthiness, yield and berry quality. Agronomy Research, 4: 247-250.
Langford, D. 1996. Fertiliser recommendations for horticulture crop strawbrries. Hort Research Publications.
Nyeki, J. 1980. Gyumolcsfajtak viragzasbiologiaja es termekenyulese. MezIgazdasagi Kiado, Budapest.
Racsko, J. 2004. Effect of auxin-synergistic preparation and fertilization on fruit setting and fruit quality of apple. Journal of Agricultural Sciences, 15: 21-26.
Racsko, J. 2006. N-phenyl-phthalamic acid and fertilization effects on flowering, fruit set and fruit quality of apple (Malus domestica Borkh). Journal of Agricultural Sciences, 24: 24-28.
Racsko, J. and Lakatos, L. 2003. Effect of N-phenyl-phtalamic acid (NEVIROL 60 WP) on quantitative and qualitative parameters of some horticultural plants. Proceeding of 3rd International Plant Protection Symposium, Debrecen, 216-224.
Tabatabaei, S.J., Fatemi, L.S., and Fallahi, E. 2006. Effect of ammonium, nitrate ration on yield, calcium concentration, and photosynthesis rate in strawberry. Journal of Plant Nutrition, 29(7): 1273-1285.
Taghavi, T.S. 2004. Strawberry Production Guide. Sana Press. [In Farsi]