Effect of Potassium Nitrate and Phenyl Phthalamic Acid on Some of Quantitative and Qualitative Characteristics of Strawberry Gaviota

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.
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.