Development of basil (Ocimum basilicum L.) lines with high essential oil and citral yield by selection breeding and determination of their yield and quality characteristics

This study was conducted in 2021 and 2022 with the aim of developing basil (Ocimum basilicum L.) lines that are rich in citral, a key component in fragrance and aroma industry, and that exhibit high essential oil yield, utilizing the pure line selection method. In the first year of the study, A lines were selected from the open-pollinated basil population, and were grown in progeny rows, followed by a single harvest. As a result of the selections, 10 plants with the highest citral yield were identified and self-pollinated. In the second year of the study, a micro-yield trial was conducted with 10 B lines (progeny), 9 A lines (parent), and 4 standard varieties. Agronomic characteristics and citral contents were examined and the lines with the highest citral yield were identified. Essential oils were isolated with hydro-distillation and citral contents were determined by GC-MS. The differences between the lines for all examined characteristics were significant statistically (p<0.01). Total essential oil yields and citral yields of A and B lines varied between 7.97-10.42 L/da and 4.99-8.03 L/da, respectively. The lines were found to be superior to standard varieties in terms of essential oil and citral yield. The highest genetic and phenotypic coefficient of variation in the lines was recorded in citral yield. The broad and narrow sense heritability for citral yield was estimated as 94.23% and 67.94%, respectively. The highest genetic advance over mean was recorded in citral yield as 33.39%. According to the results, the most appropriate criterion was to perform selection application according to citral yield in basils with lemony odor.