Effect on Yield and some Quality Characteristics of Seed Harvest at Different Stages of Maturity in Nigella sativa L.

Nigella sativa L. is a significant medicinal and aromatic plant due to its using areas of seed and fixed oil. The aim of the study was to investitigate the effects on seed yield, some yield components, fixed and essential oil content, and chemical compositon of black cumin of seed harvest at different stages of maturity. Two-year field experiments (2017 and 2018) were set up according to randomized complete block design with triplicate using a local black cumin variety obtained from Burdur province under Isparta ecological conditions of Turkey. The seed harvest (SH) in black cumin were made to four maturitiy stages. These stages were 25% (SH1), 50% (SH2), 75% (SH3) and 100% (SH4) browning of capsules. Statistically significant differences were found among the harvest stages in point of the seed yield, plant height and thousand-seed weight, while no differences were found in the numbers of capsules and branches, essential oil and fixed oil contents in both experimental years. Seed yield and its components increased during the harvest stage up to SH3, while essential oil and fixed oil contents decreased insignificantly from SH1 to SH4 in both years. According to combined years, plant height, number of capsules, number of branches, 1000 seed weight, seed yields, essential oil and fixed oil contents varied between 38.3-42.5 cm, 6.03-6.85 capsule plant-1, 6.50-6.91 branches plant-1, 2.30-2.57 g, 307.3-542.3 kg ha-1, 0.087-0.101% and 31.14-32.69%, respectively. The main components of black cumin essential oil were characterised by cymol (25.01-26.90%), thymoquinone (2.39-4.41%), carvacrol (10.12-10.41%), junipene (5.33-6.66%), Δ-3-carene (5.55-8.71%), β-pinene (2.98-3.65), trans-sabinene hydrate (8.02-11.93%) and α-thujene (7.82-9.42%) according to harvest stages in 2017 season.