Study On DNA Diversity Of AA Genome In Oryza Species

In order to estimate genetic relationships of the AA genome Oryza species, RAPD and SSR analyses were performed with 45 accessions, including 13 cultivated varieties (8 O. saliva and 5 O. glaberrima) and 32 wild accessions (9 O. rufipogon, 1 O. nivara, 3 O. glumaepatula, 4 O. longistaminata, 6 O. barthii, and 3 O. meridionalis). A total of 181 clear and repeatable bands were amplified from 27 selected RAPD primers, and 101 alleles were detected from 29 SSR primer pairs. The dendrogram constructed using UPGMA from a genetic similarity matrix based on the RAPD data supported clustering of distinct five groups with a few exceptions: O. rufipogon/O. nivaralO. meridionalis, O. barthiilO. glaberrima, O. glumaepatula, O. sativa, and O. longistaminata. The dendrogram based on the SSR analysis showed a more complicated genetic variation pattern, but the O. longistaminata and O. barthiilO. glaberrima accessions were consistently separated from all other accessions, indicating significant differentiation of the AfricanAA genome Oryza species. For accessions in the O. rufipogonlO. nivaralO. sativa complex, it is apparent that geographical isolation has played animportant role in differentiation of the Asian AA genome Oryza taxa. It is also demonstrated from this study that both RAPD and SSR analyses are powerful methods for detecting polymorphisms among the different AA genome Oryza accessions. However, the RAPD analysis provides a more informative result in terms of the overall genetic relationships at the species level compared to the SSR analysis. The SSR analysis effectively reveals diminutive variation among accessions or individuals within the same species, given approximately the same number of primers or primer pairs used in studies.