Effect of irrigation regime and foliar application of methyl jasmonate on physiological, biochemical and growth alterations of barley (Hordeum vulgare L.) varieties

Introduction Water shortage has become a global problem and has caused many problems in agriculture and food supply for the growing world. Barley (Hordeum vulgare L.) as the fourth mostly-cultivated cereal, is one of the most strategic crop plants which is produced almost all over the world as a source of and important staple food and animal feed (Thabet et al., 2020). Food uncertainty is a comprehensive obstacle becomes more serious hazard all over the world in particular in developing countries for the sake of overpopulation and dwindling accessibility of croplands, water and other resources related to agricultural scopes. Water scarcity, results in plenty of disturbances in plant functions like cell division and elongation, water and nutrients relations, photosynthesis, enzymes activity, stomata movement, assimilate partitioning, respiration, oxidative damage, growth, and productivity, as several types of researches show that water shortage in the soil cause many disorders in plant tissues, which in turn leads to a punctual diminish in the photosynthesis rate (Todorova et al., 2022). In such a trouble circumstances, most of the plants are not capable to absorb abundant water, which is required for optimized growth (Danish et al., 2020). Materials and methods To investigate the impact of different irrigation regimes as well as foliar application of methyl jasmonate on growh, physiological and biochemical characteristics of barley varieties, an experimental research using factorial split plot design in 3 replications was carried out in experimental farm of the faculty of agriculture at the University of Zanjan in 2021-2022 cultivation season. In this experiment, irrigation regimes as the main factor, including complete irrigation as the control, withholding water in flowering stage, withholding water in grain filling period and complete dry farming, varieties as the secondary factor including Bahman, Sahand, Jolgeh, Abidar as well as Ansar, and foliar application of methyl jasmonate including without spraying (control) and spraying 50 μmol of methyl jasmonate were investigated. Results showed that the effect of irrigation regime had significant impact on almost all of the characteristics except chlorophyll a/b. Results and discussion Varieties showed considerable difference from the aspect of height, concentration of soluble sugar and grain yield. Effect of Methyl jasmonate on the relative water content (RWC), photosynthetic pigments, soluble sugar content, proline content, Malondialdehyde (MDA) and grain yield was significant. The highest grain yield (4762 kg ha-1) was detected when variety of Jolgeh was irrigated normally and was sprayed by 50 μmol of Methyl jasmonate and the lowest grain yield (432 kg ha-1) was seen when variety of Bahman was dry-farmed without foliar application of methyl jasmonate. Conclusion The current study illustrated that barley can be grown in drought stress conditions if the right management is set on its cultivation. Methyl jasmonate showed a significant impact on the growth characteristics, biochemical and physiological attributes of the barley, despite the fact that drought had substantial adverse effects on the studied parameters of barley. However, drought resulted in different properties in barley varieties.