Phosphate and potassium fertilization on agronomic and physico-chemical characteristics and bioactive compounds of eggplant

Adubação fosfatada e potássica nas características agronômicas, físico-químicas e nos compostos bioativos da berinjela

ABSTRACT

Eggplant is a functional food rich in antioxidants and its consumption brings several benefits to human health. Phenolic compounds and anthocyanins are some of the compounds that interfere in this antioxidant capacity and may be influenced by the mineral nutrition of the plant. The objective was to analyze the effects of potassium and phosphate fertilization on the agronomic and physico-chemical characteristics and bioactive compounds of eggplant fruits. The work was carried out at the Taboquinha Farm, in the municipality of Baldim, MG, at coordinates 19º 17’ 12.5” S and 43º 54’ 01” W, from March to October 2017. The experimental design was randomized blocks in a 4 x 4 factorial scheme with four replicates. The factors under study were phosphorus and potassium represented by four doses of P₂O₅ (0, 60, 120 and 180 kg ha^-1) and four doses of K₂O (0, 25, 50 and 75 kg ha^-1), respectively. It was concluded that potassium and phosphate fertilization did not improve the agronomic and physico-chemical characteristics of eggplant fruits; however, potassium fertilization in greater amounts promoted improvements in the contents of phenolic compounds. The lack of phosphorus increased the anthocyanin content in the fruits, but interfered negatively in their shape. Potassium and phosphate fertilizations produced antagonistic effects on fruit moisture content.

Key words:
mineral nutrition; anthocyanins; phenolic compounds