Effect of methanol and salicylic acid foliar application on some of physiological traits of winter wheat under limited irrigation

Introduction Wheat is one of the most important crops in terms of land cultivation and production in the world and plays an important role in supplying human food needs. Among the factors limiting yield, water deficit stress is the most important factor that has reduced crop production in different ways, especially in arid and semi-arid regions of the world and Iran. Methanol is a substance that, by increasing the concentration of carbon dioxide, has a significant effect on the physiology of plants and, by increasing the photosynthetic capacity, has a significant role in increasing the yield of plants, especially in environmental stress conditions. Salicylate is one of the natural growth regulators and is a natural phenolic compound that contributes to the regulation of physiological processes in plants. Considering that a large part of cultivated land in Iran has semi-arid climatic conditions and because of its special geographical position, in most parts of it, important abiotic stress such as drought, salinity and temperature, decrease the yield and, in some cases, also has led to failure in agriculture, therefore, achieving the highest yield with the least possible water consumption in the shortest time with the use of nano-compounds such as TiO2 against breeding methods that are often long-term and cost-intensive, it seems necessary that the present research also aims to achieve goals such as evaluating and identifying important physiological traits of finally winter wheat yield under water deficit stress and application of the above compound. Material and Methods In order to investigate the effects of methanol and salicylic acid foliar application on some growth and yield traits of winter wheat Mihan cultivar under water deficit stress, an experiment was conducted in split plot factorial based on RCBD in three replications at the Research Station of the Islamic Azad University, Tabriz Branch, during growing seasons of 2016-2017. Treatments were Irrigation Frequency in two levels including: irrigation every 7 days and every 14 days and factorial combination of methanol (in three levels of: 0, 10 and 20% V/V) and salicylic acid foliar application (in two levels of: non application and 0.5%). Irrigation of the farm was carried out to the stage of stem elongation according to the needs of the canopy, but after that, limiting irrigation was applied (code 31 of Zadoks growth scale).To determine the Water requirement of wheat, irrigation depth was calculated based on evaporation coefficients using evaporation pan (class A). Analysis of variance, and mean comparison with MSTAT-C software were used. The means of the treatments were compared using the Duncan’s test at P< 0.05 and Charts are plotted by the EXCEL program. Results and discussion The analysis of varianceshowed that the water deficit stress and salicylic acid on all of traits except grain filling rate and chl.a was significant. Also, effect of methanol foliar application on on all of traits except grain filling rate and relative water content was significant. Interaction effect of methanol and salicylic acid foliar application on grain filling rate and grain yield, interaction effect between water deficit stress and methanol foliar application on grain filling rate and salicylic acid foliar application under water deficit stress on seed yield were significant. Furthmore, interaction effect between water deficit stress, methanol and salicylic acid foliar application on relative water content was significant. Interaction effects of methanol foliar application in different levels of water deficit stress showed that the maximum grain filling rate under sprayed with methanol 10% and irrigation every 7 days with an average of 1.259 g day-1 and the lowest grain filling rate was also under non foliar application and irrigation treatment every 14 days with an average of 0.8552 g day-1.The interaction of methanol and salicylic acid showed that the shortest grain filling duration was in the control treatment (non-methanol.and salicylic acid application) with an average of 25.55 days and the highest was in 0.5% salicylic acid and 10%  methanol with an average of 45.38 days. The highest amounts of chlorophyll a, b and a + b was in 20% methanol foliar application and lowest was in non-methanol foliar application. Also, 0.5% salicylic acid foliar application compared to non-application increased the amount of chlorophyll b and total chlorophyll a + b. The highest relative water content was observed in 10% methanol foliar application and 0.5% acid salicylic acid and irrigation every 7 days and the lowest was in non-methanol and salicylic acid application under irrigation of 14 days with an average of 63.23%. The highest of grain yield under non-salicylic acid application under irrigation every 7 days with 751.2 g m-2 and the lowest in non-salicylic acid application under irrigation every 14 days with an average 329.4 g m-2. Also, the interaction of methanol and salicylic acid foliar application showed that the highest grain yield was in 0.5% salicylic acid and 20% methanol foliar application with an average of 7.444 g m-2 , and the lowest was in 0.5% salicylic acid and non- methanol application with average of 469.5 g m-2 .