Background & Aim: Black seed or black cumin (Nigella sativa L.) belongs the family Ranunculaceae. Black seed is one of these species, which is naturally distributed in different parts of the country. It is extensively cultivated in various regions of Iran. Experimental: The experiment was achieved using randomized complete block design with three replications in the research field of Islamic Azad University of Isfahan Branch during 2013. Seed of ten ecotypes namely; Semirom, Zawareh, Golpayegan, Fereydan, Meymeh, Kashan, Khansar, Daran, Ardestan and Isfahan were cultivated in the plots comprising four rows. The essential oil was extracted by a Clevenger type apparatus andanalyzed by using GC/MS. Results & Discussion: Statistical analysis indicated that there was significant difference among all traits. The results of regression and path analysis indicated that the number of branches, grain filling rate and days to blooming traits were the best indirect selection criteria to improve yield in black cumin. According to the results of this research, Fereydan and Daran ecotypes showed the optimum amount of essential oil content andmorphological traits. Furthermore, cross between these ecotypes has suitable advantage to increase seed and oil yield in black cumin breeding programs. Industrial and practical recommendations: There are few researches about breeding of black cumin. The results of present study could be applied in research centers as well by farmers to cultivate commercially and production black cumin especially for seed. پرونده مقاله