Morphological and yield related traits, essential oil and oil production of different landraces of black cumin (Nigella sativa) in Iran

Black cumin (Nigella sativa L.) is an annual medicinal plant belonging to the buttercup family (Ranunculaceae). It is native to Mediterranean regions, India and the Middle East. This plant is used mostly as spice and also in traditional medicine but today it is also considered in modern pharmaceutical industry. It is cultivated in different provinces of Iran with different climates. The object of this research was to study the variation of morphological, growth and agricultural yield related characteristics of this landraces in different parts of Iran. For this object, 16 landraces were collected from different regions of Iran with different climate conditions and then were cultivated in a same climate condition in a Randomized Complete Block Design (RCBD) with three replications for two years (2015–2016). Morphological traits like plant height, plant diameter, crown diameter, length and diameter of the capsules, number of branches, length and diameter of seeds and yield related parameters like number of capsules per plant, number of capsule carpels, capsule weight per plant, number of seeds per capsule, seed weight per plant, biological yield and seed yield were measured. Also essential oil and fixed oil contents were studied. Results showed that landraces of moderate regions have more seed yield and highest yield related parameters like biological yield, Seed weight per plant, Number of seeds per capsule, capsule weight per plant, number of capsules per plant, plant diameter and plant height. The highest seed yield was obtained in Hamedan landrace (186.64 g/m2) while landraces of dry regions had more Harvest index and 1000 seeds weight. Correlation coefficients studies showed that it is a strong correlation between seed yield and parameters like biological yield, Number of seeds per capsule, number of capsules per plant, plant height, plant diameter and number of branches. The percentage of oil content and essential oil among land races varied in a range of 27–33% and 0.68–1.33% respectively.