本项目针对甘草属乌拉尔甘草、光果甘草、胀果甘草分布结合区的自然杂交、杂交类群的复杂性和争议种的分类鉴定问题，对3种不同生境（荒漠、自然林、人工开垦地边缘）下形成的自然杂交区，开展杂交类群的杂交起源、杂交区物种构成、基因渗入、适应进化研究。首先通过形态性状、nrDNA的ITS和cpDNA的片段（rbcL、matK、trnH-psbA）测序、变异位点分析，阐明自然杂交区的杂交类型及亲本来源，揭示自然杂交种和困难类群的身份；在此基础上，联合SSR分子标记和DNA序列分析方法，研究3种不同生境下杂交区的构成、基因渐渗方向和程度，揭示不同环境选择压力下，自然杂交对甘草属物种形成和分化的影响；最后，通过种子园试验，比较亲本及其杂交后代的花粉流和幼苗适合度，探讨杂交的适应性进化意义。研究对揭示甘草属物种杂交进化机制以及系统分类、种质资源的合理利用具有重要意义。

Natural hybrid phenomena exist in three plants of Glycyrrhiza uralensis Fisch., Glycyrrhiza inflata Bat. and Glycyrrhiza glabra L. It causes much difficulty in identification and classification for complex species from different hybrid zones. Therefore, we are to investigate natural hybrid origin, introgression and adaptive evolution of the complex species from hybrid zones formed by desert, natural forest and reclaim land border. Firstly, we are to analyze the morphological traits, internal transcribed spacer (ITS) on nuclear ribosomal DNA, the rbcL gene, the matK gene, and the trnH–psbA intergenic region on chloroplast DNA (cpDNA) for evidence of hybridization. Then, we are to study the difference of the extent, direction and dynamics of introgression among the three species in hybrid zones for exploration the effects of natural hybrid on differentiation and speciation in Glycyrrhiza L under different environmental selection pressures. Furthermore, we are to comparatively analyze pollen flow, genotypes and fitness of seedlings among parental species and the hybrids for discussion on adaptive evolution of hybrid species.