干旱已严重限制内蒙古自治区饲草生产，提高饲草的抗旱性成为目前亟待解决的问题之一。针对内蒙古牧区草地畜牧业发展急需开发利用抗旱、高产、适应性强的饲草新品种的实际问题。我们将加拿大披碱草和老芒麦分别与披碱草、肥披碱草、圆柱披碱草、紫芒披碱草相组配进行种间远缘杂交，成功获得了5个种间杂种F1代，研究发现杂种F1叶片宽大，抗旱性、分蘖性和再生性均很强，杂种平均优势明显，具有重要的育种价值。本项目拟通过干旱胁迫处理，对5个种间杂种F1抗旱性优势进行鉴定，采用MSAP方法，研究干旱胁迫对杂种F1及双亲材料所引起甲基化变化规律，发生甲基化变化的基因及其抗旱功能。利用数字基因表达谱深度测序、了解干旱胁迫下，种间杂种F1及其亲本材料的基因表达情况；通过基因表达差异分析，发掘影响植物抵抗干旱胁迫过程中的基因。揭示种间杂种F1抗旱优势产生的分子机理及形成的分子基础，为下一步抗旱品种的选育奠定基础。

Drought stress has seriously limited grass production, and the improvement ofgrass drought resistance is one of the most urgent problems to be solved in grassland husbandry in Inner Mongolia. According to the need for new grass varieties with high yield, strong resistance and wide adaptability, we carried out distant hybridization using Elymus Canadensis and Elymus sibiricus as one parent and Elymus dahuricus、Elymus excelsus、Elymus cylindricus、Elymus purpuraristatus as the other parents, and five hybrids of F1 generation were obtained. The F1 plants.have obvious heterosis of larger leaf area, higher drought resistance, more tillering and better reproducibility, and they have great value in breeding and heterosis studies. In this project, under drought treatments, the heterosis on drought resistance of the five F1 hybrids will be quantified. Using MSAP method,methylation difference between the hybrids and their parents will bestudied, the methylated genes will be cloned and the gene function in drought resistance willbe discussed. Using high-throughput sequencing and the digital gene expression profiling analysis, the gene expression difference between the hybrids and the parents will be compared, and the genes involved in drought resistance will bedeplored. The results will lead us to uncover the molecular mechanisms of drought resistance heterosis, and provide basis for drought-resistant variety breeding.parents will be compared, and the genes involved in drought resistance will be deplored. The results will lead us to uncover the molecular mechanisms of drought resistance heterosis, and provide basis for drought-resistant variety breeding.