Identification of yield and some quality traits of different basil (Ocimum basilicum L.) genotypes in Mediterranean climate conditions

Basil is one of the most valuable medicinal and aromatic plants grown in tropical and subtropical climates, known for its distinctive aroma. Determining standardized genotypes that are adapted to regional conditions, high-yielding, and possessing a specific chemical profile is of great importance. In this study, the aim was to identify the most industrially suitable genotypes by evaluating the yield and quality performances of 90 different basil genotypes under Mediterranean climatic conditions. The study was conducted according to the augmented experimental design at the Research and Application Area of Çukurova University during the 2023 and 2024 growing seasons. Agronomic measurements, spectrophotometric analyses, and essential oil component analyses via GC-MS were performed. Statistically significant differences were detected among the genotypes regarding basic yield and quality traits. Genotypes MT30 and MT76 were identified as the most superior and stable genotypes of the population in terms of fresh herb yield (4177.67 kg/da and 3514.90 kg/da, respectively), dry herb yield, and dry leaf yield, consistently exceeding the calculated threshold values (highest control mean + least significant increase). Morphologically, MT72 and MT80 achieved the largest leaf area, while MT89 reached the highest branching capacity. When total phenolic content, DPPH, and ABTS radical scavenging activities were examined, genotypes MT08, MT86, MT38, and MT67 stood out with their high bioactive component content. In essential oil analyses, while MT63 and MT74 presented high oil content, the general chemical structure of the population was grouped under five main chemotypes: linalool, methyl chavicol, citral, methyl cinnamate, and eugenol. This comprehensive characterization study, in which superior genotypes serving different usage purposes were identified, will contribute to meeting the high-quality raw material needs of the national pharmaceutical and cosmetic industries and will constitute a strategic foundation for future breeding programs. Keywords: Basil, Ocimum, Chemotype, Antioxidant activity, Secondary metabolites