Effects of Different Irrigation Regimes and Nitrogen Fertilization on the Physicochemical and Bioactive Characteristics of onion (Allium cepa L.)

The availability of water and nitrogen in the soil affect metabolism onion bulbs. synthesis metabolites bioactive compounds are most affected, along with quality bulbs However, it is necessary to know effects different levels fertilization optimize onion. objective this research was study conditions hydric stress during development (Allium cepa L.) crop, regarding its physicochemical properties. Onions were grown using four available irrigation regimes (25, 50, 75 100%) doses (100, 150, 200 250 kg N ha?1). Onion without any treatment considered as a control. treatments low increased pH level (5.7 5.9) bulb coloration bright white/yellowish tones. An increase observed compared control titratable acidity (0.13%) just content, ascorbic acid (46%) antioxidant capacity DPPH (12.3%) ABTS (93.7%). A decrease shown soluble solids (14.6%), firmness (3.5 cm?2), dry matter (6.6%), total phenols (50%) FRAP (33.2%) values. Pyruvic remained constant (1.5 µmol g?1 FW). extracts showed an erythroprotective effect hemolysis inhibition percentage higher than 95%. Finally, onions had pungency, soft extra sweet. 25% usable humidity 150 ha?1, favored physical, chemical bulb.