Effect of planting date and plant density on yield and seed yield components of Plantago ovata

In order to study the effect of planting date and plant density on yield and seed yield components of isabgol (Plantago ovata L.), an experiment was conducted at Agricultural research center of Islamic Azad University Birjand Branch, in 2008. The experimental design was split-plot based on randomized complete blocks with three replications. Main plots consisted of three planting date (18 April, 9 and 30 May), and sub-plots included three density levels (16.6, 22.2 and 33.3 plants. m-2). The results showed that delay in planting date from 18 April to 30 May significantly decreased number of spikes per plant (35.2%), number of seed per spike (39.8%), seed yield (60.2%), biological yield (49.3%) and harvest index (19.7%). Plant density had significant effect on number of spikes per plant and per m2 biological yield, seed yield, harvest index and seed yield per plant. According to the results, it could be concluded that planting date and plant density are effective parameters in crop performance. In this research, planting date of 18 April and plant density of 33.3 plants m-2 had the highest seed yield (558.99 kg ha-1).