| Azuki bean (Vigna angularis Ohwi and Ohashi) is one of the principal edible beans in china. It is very important in agricultural production and people's normal life. In the past few years, along with the improvement of people's living standard and the change of the dietary pattern, demands of azuki bean have increased greatly. However, the foundation and application research of azuki bean is relative lagged, and the breeding of it is limited with routine methods. The selection process of new species can not keep up with the society demands. Therefore, the detection of new outstanding germplasm resources seems to be extremely urgent. The study of genetic diversity is available to the collecting and protecting of rare gene resources as well as to the full exploitation of gene resource. The development of the molecular biotechnology has provided more convenience for the further systematic evaluation of gene resources. This study evaluated the genetic diversity of the cultivated azuki bean (Vigna angularis var. angularis) germplasm from Chinese geographical regions through 2 molecule markers (RAPD and AFLP). The main results are as follow:1. Genetic diversity of 94 cultivated azuki bean germplasm from Chinese geographical regions was evaluated using random amplified polymorphic DNA (RAPD) markers. A total of 107 bands were amplified from 10 primers, of which 96 bands (about 89.7%) were polymorphic. 6 to 13 polymorphic bands could be amplified from each primer, with an average of 9.6 bands. The mean genetic similarity ((GS) value based on RAPD markers among 94 azuki bean germplasm was 0.736, ranging from 0.191 to 1.000. 90 of the 94 accessions could be distinguished by RAPD markers.2. Clustering results indicated that genetic diversity of azuki bean germplasm based on RAPD markers were disagree with the morphologic characteristics, and have nothing to do with geographical distribution and life habit, 93 azuki bean germplasm were randomly clustered into 3 groups.3. Genetic diversity of 94 cultivated azuki bean germplasm from Chinese geographical regions was evaluated by using amplified fragment length polymorphism (AFLP) markers. Atotal of 855 bands were amplified from 10 primers, while 315 bands (about 36.8%) were polymorphic. 14 to 50 polymorphic bands could be amplified from each primer, with an average of 31.5 bands. The AFLP based genetic similarity (GS) among 94 azuki bean germplasm ranged from 0.183 to 0.998, with a mean of 0.715. All the 94 accessions could be distinguished by AFLP markers.4. Clustering results indicated that the genetic diversity of 94 azuki bean germplasm based on AFLP markers were clustered into 4 groups, the 73th azuki bean germplasm come from ya'an Sichuan had evident genetic diversity and was clustered into a single group. Its inheritance is to be further studied. The relationship of other azuki bean germplasm wascloser. Clustering results were conformed to the morphologic characteristics. Morphologic characteristics within each group were almost the same. It was showed that the clustering results were also associated with the growing habits. Species in the same or similar climate were clustered into the same group. The spring sowed species were clustered apart from the summer and autumn sowed ones.5. These results suggested that RAPD and AFLP markers could be used as effective molecular techniques to evaluate the genetic diversity of azuki bean. AFLP had an obviously advantage over RAPD. AFLP could detect tiny diversities among different species. AFLP clustering was also associated with the geographical distribution of germplasm, which could be used to detect the genetic variation caused by geographical distribution.
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