Studies On The Genetic Diversity Of Mongolian Wheatgrass(Agropyron Mongolicum Keng)

Mongolian wheatgrass (Agropyron mongolicum Keng) is a cross-pollinated, longlived, cool-season and drought-resistant perennial bunchgrass, which has a wide distribution in the Northwest and North China, particularly in Inner Mongolia. Not only does it has an important economic value, but an important ecological and genetic value. Using the materials of six natural populations and two cultivars from the central and east regions in Inner Mongolia, the statistical analysis of the phenotypic quantitative characters of inflorescence, the scanning electron microscope analysis of the micro-morphological characteristics of lemma surface, the allozyme variation and the RA.PD analysis were performed with a view to assessing the genetic diversities and their distribution pattern within and among populations. The results showed that A.mongolicum possessed a higher level genetic diversity within population than that among populations as a result of the cross-pollinated breeding system. Between natural populations and cultivars, the genetic diversity among six natural populations was much higher than that between two cultivars, owing to the environmental heterogeneity of natural populations. In the meantime, there also was a genetic differentiation between two cultivars. It was clear that artificial selection played an important role in the differentiation. UPGMA cluster analysis showed that eight populations could basically be divided into three groups adapted to their own soil conditions. These groups were sand-land populations, gravelly-slope populations and sandy soil cultivars respectively. It is enough to prove that natural and artificial selections have a enormous effect on the differentiation among populations. The abundant genetic diversities of A. mongolicum are the foundation of the utilization of this germplasm resource. The drought-resistant, cold-resistant and barren-tolerant traits can provide some helps for the improvement of kindred crop cultivars, for the water and soil conservation of sand land, and for the construction of artificial grassland. Therefore, the mongolian wheatgrass is a potential and precious germplasm resource.