Characterization of genetic variation and relationships among Choix germplasm accessions using RAPD markers

Choix, a plant in the tribe Maydeae of the grass family, has been cultivate d in Asia for several thousand years. It is a potential gene resource for i mprovement of other cereal crops because of its nutritional value and toler ance to stress. Genetic variation and relationships among 21 Choix lachryma -jobi L. accessions were characterized by random amplified polymorphic DNA (RAPD) markers. A total of 205 DNA fragments across all materials were ampl ified with 31 random primers, averaging 6.61 per primer. Among amplified fr agments, 115 showed polymorphism averaging 3.71 per primer. Of amplified ma rkers, 56.1% were polymorphic, indicating considerable variation at the DNA level among these accessions. Some fragments were accession-specific. Pair -wise genetic similarity (GS) among 21 accessions ranged from 0.809 to 0.30 1. The 21 accessions clustered into two major groups. Three exotic Choix ac cessions clustered together. Three other Choix accessions, collected from G uangxi, China, clustered into a cohesive subgroup. Four wild types of Choix clustered into the same subgroup. These results indicated that the classif ication by RAPD data reflected the differences in geographic origins and ev olution in Choix.