Effects of Foliar Application of Fe and Zn on Seed Yield and Mucilage Content of Psyllium (Plantago psyllium) at Different Stages of Maturity

In order to evaluate the effects of foliar application of micronutrients (iron and zinc) and different harvesting times during seed filling on yield and mucilage percentage of psyllium (Plantago psyllium), a field experiment was carried out in 2009 at the Research Farm of the Faculty of Agriculture, University of Tabriz, Tabriz, Iran. The experiment was arranged as split plot based on randomized complete block design with four replications. The treatments were foliar application of Fe, Zn and Fe+Zn (using ferrous sulphate and zinc sulphate at the concentration of 0.35% for the both micronutrients) with the control and four harvesting times during seed filling. The results showed that seed yield, seed swelling and mucilage percentage were increased by foliar application of Fe and Zn, compared with control (untreated). The highest seed yield (832.5 kg.ha-1), seed swelling (12.78 ml) and mucilage percentage (8.35%) were recorded for spray treatment by about 31.04, 21.71 and 41.52 % improvements in comparison with control, respectively. Different harvesting times had significant effect on seed yield, seed swelling and mucilage percentage.  The highest seed yield was obtained at seed maturity stage. At this stage seed swelling and mucilage percentage were the lowest, but this was overcome by large improvement in seed yield. It seems that foliar application of iron and zinc can considerably improve seed yield, seed swelling and mucilage content of psyllium.