Biochemical, Physiological and Yield Characteristics of Red Basil as Affected by Cultivar and Fertilization

Unconventional fertilizers can act as elicitors to encourage the synthesis of phyto-pharmaceuticals in aromatic plants. In the present research, the effects of factorial combination between two red basil cultivars, ‘Opal’ and ‘De Buzau’, and four fertilization types, biosolids, organic, microorganisms and chemical, plus an unfertilized control, were assessed on fresh and dry yield, biometrical parameters, soil plant analysis development (SPAD) and antioxidant compounds and activity. Chemical fertilization increased fresh yield compared with the control, with no difference in organic and microorganism fertilization regarding dry weight. ‘De Buzau’ enhanced the number of lateral stems and plant height, the latter being better affected by chemical and microorganisms compared to the control. Chemical fertilization showed the highest leaf dry matter, nitrate content and SPAD, whereas the control showed the lowest. Compared to the unfertilized control, biosolids increased total phenolics in ‘Opal’; microorganisms, organic and biosolids enhanced total flavonoids in ‘Opal’, with the same effect under microorganisms and organic treatments in ‘De Buzau’. Total anthocyanins showed the highest content in ‘Opal’ under organic fertilization. The highest antioxidant activity in the basil extracts was detected under microorganisms and organic applications in ‘Opal’. The present investigation results demonstrate that unconventional fertilizers increase the synthesis of antioxidants and represent a sustainable alternative to chemical fertilization for growing red basil.