Growth and Fruit Biochemical Characteristics of Three Strawberry Genotypes under Different Potassium Concentrations of Nutrient Solution

A nutrient solution experiment was performed to evaluate the growth, yield and fruit biochemical characteristics of strawberry under different potassium levels of nutrient solution. Potassium concentrations including 235 (control), 350, 450 and 600 mg L-1 were applied to three strawberry genotypes of Camarosa, Selva and Parus under hydroponic culture. In the three genotypes, the maximum leaf area was observed at 350 mg L-1 K, and the maximum shoot fresh weight was either at 350 mg L-1 (in Camarosa and Parus) or at 400 mg L-1 (in Selva). In Selva, higher yield was produced by higher K concentrations than control (17-33%) and in Camarosa, the maximum yield was produced at 350 mg L-1 (16%), whereas fruit yield in Parus was not affected by K concentrations. In Selva and Parus application of 350 mg L-1 potassium produced more fruits than control. The maximum fruit vitamin C content in Camarosa and Selva was at 350 mg L-1, and in Parus at 450 mg L-1, while the significant lowest in three genotypes was at 600 mg L-1. Fruit titratable acidity and pH in Camarosa and Selva, and fruit TSS in Parus were not affected by K levels. Fruit total soluble solids (TSS) in Camarosa and Selva were maximum in 350 and 450 mg L-1. Increasing K concentrations of nutrient solution increased leaf and fruit K concentration than control. The results indicate that overall plant growth and fruit quality of three strawberry genotypes were increased by 350 mg L-1 potassium, while application of 600 mg L-1 reduced most traits than control. The Selva genotype had also a better response to higher concentration of K than two other genotypes.