Drought is the most important factor limiting crop production in arid and semiarid regions of the world. Epigenetic changes including DNA methylation are involved in response to environmental stresses such as drought. In this study, the coupled restriction enzyme digestion-random amplification (CRED-RA) technique was used to evaluate the methylation patterns in leaf of two Iranian barley cultivars “Afzal and Sararood” and one European barley cultivar “Aiace” in four moisture stress regimes (irrigation at 100%, 75%, 50% and 25% of field capacity) in three stages including before the application of drought stress, 14 days after stress and 14 days after re-irrigation in three replications. The measured traits were relative water content, photochemical efficiency of photosystem II (Fv/Fm), transpiration rate, sub-stomatal CO₂ concentration and leaf surface temperature. The highest methylation changes observed in all three cultivars were the conversion of full methylation to external cytosine methylation. The highest instability of genome pattern was observed in Aiace cultivar and in OPB-07 primer in irrigation at 25% of field capacity. Although most of the methylated and de-methylated fragments switched to pre-stress state after irrigation, there were few fragments that remained stable in the plant's genomic memory. Results showed significant changes in methylation pattern of all three barley cultivars in response to moisture stress.

干旱是世界干旱和半干旱地区限制作物生产的最重要因素。包括 DNA 甲基化在内的表观遗传变化参与应对干旱等环境压力。在这项研究中，耦合限制酶消化-随机扩增 (CRED-RA) 技术用于评估两种伊朗大麦品种“Afzal 和 Sararood”和一种欧洲大麦品种“Aiace”在四种水分胁迫情况下的叶片甲基化模式（以田间持水量的 100%、75%、50% 和 25% 灌溉）三个阶段，包括施加干旱胁迫前、胁迫后 14 天和再灌溉后 14 天，三个重复。测量的性状为相对含水量、光系统II的光化学效率(Fv/Fm)、蒸腾速率、亚气孔CO ₂浓度和叶面温度。在所有三个品种中观察到的最高甲基化变化是完全甲基化向外部胞嘧啶甲基化的转化。在 Aiace 栽培品种和 OPB-07 引物中以 25% 的田间容量灌溉时观察到基因组模式的最高不稳定性。尽管大多数甲基化和去甲基化片段在灌溉后切换到预应力状态，但很少有片段在植物的基因组记忆中保持稳定。结果表明，响应水分胁迫，所有三个大麦品种的甲基化模式都发生了显着变化。