| Genetic diversity of crops is the base for genetic improvement of crops, it is important for the collection, conservation, evaluation and utilization of crop germplasm. Broomcorn millet (Panicum Miliaceum . L) is an ancient grain crop in China, with characters of short growth season, drought tolerant, sterile soil grown, as well as good nutritives. Shaanxi, Shanxi, Inner Mongolia and Ningxia are the major production regions of broomcorn millet in Northern China, there are rich genetic resources of broomcorn millet in above region (about 58% of the total germplasm in China). How to conserve and utilize those germplasm efficiently is an important issue for the genetic improvement of broomcorn millet and other crops.58 broomcorn millet germplasm were collected as the materials for this study and those germplasm were from two parts, one part is 38 germplasm of landraces and cultivars from Shaanxi, Shanxi, Inner Mongolia, as 6 Indian germplasm as well;another part is 20 cultivars bred by the Guyuan Institute of Agricultural Scienes and widely used in Southern Ningxia and Eastern Gansu. The PCR based molecular markers were used to detect the genetic diversity by means of introns splice junction primers and long random primers, at the same time, genetic diversity based on agronomic traits were also detected and compared.1. The PCR based molecular markers were used to detect the genetic diversity among the 38 landrace and cultivar collection from different ecological region of Northern China, as among 20 cultivars bred by Guyuan Institute of Agricultural Sciences as well. The results showed that the rich polymorphic bands were detected with polymorphic frequency of 75% and 90.38% respectively. Therefore the introns splice junction primers and long random primers were suitable for the analysis on the genetic diversity of broomcorn millet. The gentic distances based on the molecular markers were estimated and the dendrogram were established by UPGMA method, the clusters could reflect the genetic relations among those germplasm well. Therefore, this PCR based approach is a good tool for detect genetic diversity.2. Based on the PCR based molecular markers, cluster analysis among the 38 landrace and cultivar collection from different ecological region of Northern China revealed that some landraces and cultivars could be clustered into the same cluster, such as Jinmi 4 and MDahuangmi, Neimi 2 and M Niulandanmi, it revealed that landrace was efficiently used in the improvement of germplasm, but most landraces were still isolated with cultivars, it reflected that there still are great potential for the germplasm improvement by the more efficient use of landraces.3. Based on the PCR based molecular markers, cluster analysis among 20 cultivars bred by Guyuan Institute of Agricultural Sciences revealed that the cultivars could be clustered into two groups, one group is derived from germplasms Gugutou and 64211, another group is derived from germplasms Fengshou 3 and Yanbeidahuangsu, the cluster result could fit the breeding pedigree well.4. Genetic diversity were detected based on the PCR based molecular markers and the agronomic traits as well. Although there are some differences observed, but the genetic diversity among germplasm could be revealed more deeply. The reason for this difference could be due to the errors caused by observation in different environment and the observation itself.5. The cluster result based on PCR based markers and agronomic traits also revealed that Indian germplasm 790045 and 790037 could be clustered into the same group with Chinese landrace S Jiaozuimi and cultivar 8414-1-12-1, respectively;it could be evidence that China is the origin center of Broomcorn millet.6. The PCR based approach used in this research may provide some practical tools for the genetics diversity research on Broomcorn millet, also could be useful for the genetic diversity research in other crops.
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