The Effect of Water Stress and Plant Density on Yield and Yield Components of Cumin (Cuminum cyminum)

To study the effect of water deficit and plant density on yield and yield components of cumin (Cuminum cyminum), an experiment was conducted during the 2002 - 2003 growing season at Research Farm of Zabol University. In this study, the effects of plant density (25, 50, 100, 150, and 200 plants per m²) and water stress (before flowering, flowering, seed filling and seed hardening vs adequate irrigation) were investigated. The experiment was a split plot one, with RCBD of 3 replications. The results showed that the effect of plant density on number of umbels per plant, number of seeds per umbel, plant yield and seed yield per hectare was significant (?<0.01) but the effect of plant density on one thousand seed weight was not significant. The effect of water stress on number of umbels per plant, number of seeds per umbel, one thousand seed weight, plant yield and seed yield per hectare was significant (?<0.01). The effect of plant density on one thousand seed weight was non significance. Water stress reduced the number of umbels per plant, number of seeds per umbel, one thousand seed weight, plant yield, as well as seed yield per hectare. In a high plant density, seed yield per hectare was maximum but the number of umbels per plant, number of seeds per umbel, and plant yield were at their minimum. According to the results of this study, to achieve maximum yield, cumin must be supported with sufficient moisture especially in early reproductive stages and optimum plant density.