Effects of methanol on grain yield, chlorophyll fluorescence indices and some physiological traits of wheat (Triticum aestivum L.) under irrigation withholding conditions

Introduction:

 Drought stress is the most influential factors affecting crop yield particularly in arid and semiarid regions. This stress induces various biochemical and physiological responses in plants as a survival mechanism. Drought limits plant production and the performance of crop plants, more than any other environmental factor. Also this stress can damage the photosynthesis of plants and reduce chlorophyll content, relative water content, stomatal conductance and quantum yield. One of the important strategies for increasing of carbon dioxide concentration in plants is using compounds such as methanol that can increase the concentration of CO2 in a plant and help photosynthesis rate and growth under water deficit conditions. The aim of this study was to investigate the effects methanol on yield, chlorophyll fluorescence indices and some physiological traits of wheat (Triticum aestivum L.) under irrigation withholding conditions .

Material and method:

 A factorial experiment was conducted based on randomized complete block design with three replications at the research farm, faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili during 2018-2019. Factors experiment were included irrigation at three levels (full irrigation as control, irrigation withholding in 50% of heading and booting stages as moderate and severe water limitation respectively according with 43 and 55 BBCH scale) and foliar application of methanol at four levels (foliar application with water as control, application 10, 20 and 30 volume percent).

The results showed that irrigation withholding decreased quantum yield, maximum fluorescence (Fm), variable fluorescence (Fv), chlorophyll index, relative water content, stomatal conductance and grain yield. Whereas electrical conductivity, electrolyte leakage and minimum fluorescence (F0) increased. Foliar application of 30 volume percent of methanol under full irrigation increased about 51.53, 170.75, 78.76, 55.69, 77.58, 79.4 and 46.98% maximum fluorescence (Fm), variable fluorescence (Fv), quantum yeild (Fv/Fm), chlorophyll index, relative water content, stomatal conductance and grain yield respectively in comparison with no foliar application of methanol under irrigation withholding in booting stage condition. Also, foliar application of 30 volume percent of methanol under full irrigation condition decreased electrical conductivity, electrolyte leakage and minimum fluorescence (F0 122.68, 73.07 and 42.59% respectively in comparison with no foliar application of methanol under irrigation withholding in booting stage condition

Based on the results of this study, it seems foliar application of 30 volume percent of methanol can increase grain yield of wheat under water limitation condition due to improve fluorescence indices and some physiological traits such as stomatal conductance, relative water content and chlorophyll index