Effect of methanol foliar application and drought tension on grain yield and growth indices of soybean (Glycine max L.)

In order to investigate the effect of methanol foliar application and drought tension on growth indices of soybean, an experiment was conducted as split plots in a randomized complete blocks design with three replications in the research field of Faculty of Agriculture, Islamic Azad University of Karaj Branch in 2015. Drought tension included irrigation after 40, 60 and 70 percent available moisture evacuation as the main factor and methanol foliar application included no spraying (control), spraying with 7, 14 and 21 percent by methanol volume as the sub factor were considered. Spraying was carried out three times during the plant growth season and at intervals of 15 days on the aerial parts. The measured traits included: dry matter accumulation, grain yield, crop growth rate, relative growth rate, net assimilation rate, Proline, soluble sugars, Peroxide hydrogen and relative moisture content. The results showed that the effect of methanol foliar application in drought tension conditions, was significant on the relative increase of all growth indices and yield. The comparison of the average of the examined traits showed that methanol foliar application had a positive and significant effect on soybean growth indices which led to increasing dry matter and grain yield of soybean; as the highest grain yield was obtained during methanol foliar application with 21 percent volume. Moreover, under mild and severe tension conditions with application of the highest amount of methanol, the amount of peroxide hydrogen reached to the lowest level. According to the obtained results, with application of 14 percent methanol, more increase was observed in the efficiency of proline under severe tension conditions. Increasing the volume of methanol from 7 to 14 percent, the relative water content was preserved under tension conditions.