Effect of different irrigation intervals and plant density on yield and yield components of Black Cumin (Nigella sativa)

In order to investigate the effect of different irrigation intervals and plant density on yield and yield components of Black Cumin (Nigella sativa), an experiment was conducted at Research Station, Faculty of Agriculture, Ferdowsi University of Mashhad, in 2002. A split-plot layout based on randomized complete block design with four replications was used. Irrigation intervals (7, 14 and 21 days) were allocated to main plots and different plant densities (150, 200, 250, 300 and 350 plant/m2) allocated to sub plots. Plant height, number of branch per plant, number of grain per plant, number of seed per follicule, number of follicule per plant, grain weight per plant, biomass, 1000 seed weight, grain yield and harvest index were recorded. Results showed that irrigation intervals had significant effects on all of the characteristics with the exception of 1000 seed weight and harvest index (HI). Plant density did not have significant effects on 1000 seed weight, number of seed per follicule and plant height. There were significant differences between biological yield, HI, number of follicules per plant and grain yield of different plant densities. The one week irrigation interval produced more grain yield compared with the three weeks irrigation intervals (752 vs. 355 kg/ha). The greatest grain yield was obtained with one week irrigation interval and 250 plant/m2. It seems that due to the lack of water in the area, 150 – 250 plant/m2 with two weeks irrigation interval is the best combination for Black Cumin grain production in Mashhad.