The Effects of Number of Irrigations on Development Stages , Yield and Yield Components of Cumin

In order to determine the effects of number of irrigations on stages of development, yield, and yield components of cumin, an experiment was conducted in 1993 - 94 growing season with a randomized complete block design and four replications. The location of the experiment was Isfahan University of Technology Research Station in Shervedan Field. The irrigation treatments were: I1- Irrigation after planting I2- Irrigation after planting and at the stage of full standing of plants I3- Irrigation after planting, full standing of plants, and anthesis and I4- Irrigation after planting, full standing of plants, anthesis, and beginning of grain filling stage. The stages of development (from emergence to anthesis) occurred simultaneously in all treatments. However, the water deficit in I1 and I2 caused the plants to reach their physiological maturity 5 days sooner than the other two treatments. The time intervals between anthesis and physiological maturity in I4 and I3 treatments were 12 days and 5 days longer than those in the other two treatments, respectively. The grain yield of I1 and I2 were approximately 60% of I3 and no significant difference was observed between the grain yields of I1 and I2 treatments, nor between I3 and I4 treatments. The grain yields in I3 and I4 treatments were about 1742 and 1800 Kg/ha, respectively. The number of umbels per plant, the most important grain yield component, was greater in I3 and I4 than the other two irrigation regimes, but the number of seeds per umbel and 1000-seed weight of I3 and I4 were lower than that in I1 and I2 treatments.