Estimation Of Genetic Changes In Rice Mutants After Gamma Irradiation Using RAPD And RAMP Markers

Two Vietnamese rice mutants (M2-2 and M2-4 - second generation line 2 and line 4 respectively), induced by gamma irradiation were examined and compared to their parent (TT1), and the Australian cultivar Amaroo (Am) for genomic differences. Tissue cultured shoots provided high yields and good quality of DNA, especially with young rice tissue. Changes in DNA of the mutants in comparison to TT1 and Am were successfully assessed using two molecular techniques known as RAPD-PCR (Random Amplified Polymorphic DNA-Polymerase Chain Reaction) and RAMP-PCR (Random Amplified Microsatellite Polymorphism-Polymerase Chain Reaction). RAMP-PCR was better than RAPD-PCR at disclosing genetic changes between rice cultivars that were closely related, and only RAMP-PCR was able to detect polymorphic bands between TT1 and the mutants. The G-statistic demonstrated that comparisons between Am and TT1, M2-2 or M2-4 showed moderate genetic differentiation, but comparisons between TT1 and M2-2 or M2-4 showed low level of genetic differentiation. Percentage polymorphism between TT1, M2-2, M2-4 and Am detected by RAPD-PCR were similar to those detected by RAMP-PCR (about 10%). The results showed that RAMP-PCR is a versatile, sensitive and cost effective method for genomic analysis between cultivars and mutants. (author)