Effects of Different Potassium Levels in Nutrient Solution on the Fruit Quality in Bell Pepper

Bell pepper (Capsicum annuum L.), due to its high nutritional values, is one of the most important vegetable crops in the world. Optimum supply of nutrients particularly potassium, has important role in improving the quality of agricultural products. This research was conducted to study the effects of potassium levels (150, 235, 300, 400 and 500 mgL-1in nutrient solution) on fruit quality of bell pepper. The results showed that the effect of K levels on fruit length, fruit firmness, and biochemical traits was significant (P≤0.05), while there was no significant effects of potassium levels on fruit diameter. The highest fruit length and fruit firmness were observed in plants treated with 400 and 500 mg K L-1 nutrient solution, respectively. The highest amount of TSS and pH of fruit juice were recorded in 400 mg K L-1 treatment, whereas the highest titreable acidity and vitamin C were in plants treated with 500 mg K L-1 nutrient solution. Therefore, it can be concluded that for improvent of fruit quality of Bell pepper in hydroponic system, higher potassium concentrations (400 mgL-1) rather than normal concentrations (around 235 mgL-1) should be applied.