Effects of Temperature and Precipitation at Large Spatial Scales on Genetic Diversity, Genetic Structure, and Potential Distribution of Agropyron michnoi

The genetic diversity and the genetic structure of widely distributed species are meaningful to explore plant adaptation mechanisms to the environment. This study investigated the effects of climatic factors on the genetic diversity and structure of Agropyron michnoi, and modeled its large-scale potential distribution shifts. A. michnoi was studied under different temperature and precipitation gradients on grassland of Inner Mongolia and North China using rbcL and trnL-F sequences. The results showed that the genetic diversity of A. michnoi was low and significantly influenced by precipitation. AMOVA results showed that genetic variation in A. michnoi occurred mainly within the population, accounting for 70.57%. Both Mantel test and partial Mantel test support a significant IBE pattern. STRUCTURE and UPGMA analyses divided the populations into two clusters. Population 10 was closely related to one cluster. The haplotype network shows only one cluster H1, and all other haplotypes have evolved from H1, which is likely the ancestral haplotype. A. michnoi, as a widely distributed species. Originating from a primitive haplotype. Large scale precipitation caused genetic differentiation into two genetic branches. The MaxEnt model predicts that A. michnoi’s distribution has expanded since the Last Glacial Maximum and will shift to higher elevations in the future due to climate change.