Abstract :
To study the effect of sowing date and plant density on morphological traits and yield of fennel in research field of Islamic Azad University, Birjand branch, Iran in 2011 as a split-plot experiment based on a randomized complete block design with three replications. The main plot was sowing date at three levels of March 19, April 9 and April 30 and the sub-plot was plant density at three levels of 6.7, 10 and 20 plants/m2. The results showed that sowing date and plant density significantly affected fennel morphological traits including plant height, main branch number per plant and stem diameter at 1% level and the interaction between them significantly affected plant height and stem diameter, too. Plant height decreased by 19.2 and 48.2% at the second and third sowing dates as compared with that at the first sowing date. Forty-one-day delay in sowing decreased auxiliary branch number per plant by 59.2% and stem diameter from 5 to 1.8 mm. In addition, the increase in plant density from 6.7 to 20 plants/m2 decreased auxiliary branch number per plant and stem diameter by 26.4 and 26%, respectively, but increased plant height from 38.49 to 68.38 cm. According to the results, the effect of sowing date, plant density and their interaction was significant on seed yield. Means comparison indicated that the highest seed yield was obtained at the first sowing date and the delay in sowing significantly decreased it. Also, means comparison indicated that the increase in plant density led to significantly increased seed yield. In total, according to the results, it is recommended to use sowing date of March 10 with the density of 20 plants/m2 for the cultivation of fennel in Birjand, Iran since it produced 1163.30 kg seed per ha.
