Study on the effect of different plant density on some morphological traits and yield of safflower under irrigated and rain-fed planting conditions

In order to study the effects of different plant densities on some morphological traits and the yield of safflower under irrigated and rain-fed planting conditions, an experiment was conducted in Agricultural Research Station of Islamic Azad University–Ardabil Branch, Ardabil, Iran in 2010. It was a factorial experiment based on a Randomized Complete Block Design with four replications. The factors included planting method (irrigated and rain-fed) and plant density (30, 40, 50 and 60 plants per m2). The measured traits included plant height, main stem basal diameter, height of the first head-bearing branch from ground, seed length, main branch number per m2, secondary branch number, head number per m2, and seed yield. Results showed that the diameter and the height of the plants were higher under irrigated conditions than under rain-fed conditions. The highest height of the first head-bearing branch from ground and main branch number were observed at the density of 60 plants per m2 under irrigated conditions. The plants at the density of 30 plants per m2 under irrigated conditions had higher secondary branch number and main stem diameter. Also, the highest head number per unit area was obtained from the plants at the densities of 40 and 60 plants per m2 under irrigated conditions. The significantly highest seed length was obtained at the density of 40 plants per m2 under rain-fed conditions. The significantly highest seed yield was produced at the density of 60 plants per m2 under irrigated conditions.