Use of Intersimple Sequence Repeat Assay for Detection of DNA Polymorphism Induced by Gamma Rays in Curcuma alismatifolia

Abstract

In plant breeding programs with vegetatively propagated plants, induced mutations with low physiological effects and strong genetic effects are important approaches for broadening the genetic variation. In the present study, intersimple sequence repeat (ISSR) assays were used to identify DNA polymorphism among the mutant varieties of Curcuma alismatifolia (Chiang Mai Red, Sweet Pink, Kimono Pink) and one hybrid (Doi Tung 554) exposed to 0-, 10-, and 20-Gy optimum doses of acute gamma irradiation. To identify DNA polymorphism among the mutants (10 and 20 Gy) and non-treated (0 Gy) samples through ISSR assay, a total of 25 random primers were screened and 14 gave reproducible polymorphic bands. The number of presumed alleles revealed by the ISSR analysis ranged from three to 19 alleles with mean values of 6.5, 7.8, and 9.2 alleles per locus for doses of 0 (control), 10, and 20 Gy, respectively. The average effective number of alleles, Nei’s gene diversity, Shannon’s information index, and polymorphic information content (PIC) were 1.41 to 1.48, 0.24 to 0.33, 0.35 to 0.45, and 0.21 to 0.25 for the three doses, respectively. Percentages of polymorphic loci for non-irradiated (0 Gy), 10 Gy, and 20 Gy individual plants were 76.4%, 83.7%, and 85.8%, respectively, with an average of 81.9%. Jaccard’s genetic similarity coefficient varied from 0.19 to 1.0 indicating the level of genetic variation among the mutants studied. In terms of variety, the range of genetic variation (0.27 to 0.4) among individuals of the Doi Tung population was more than that observed in the other three varieties. In a dendrogram constructed based on genetic similarity coefficients, the 44 C. alismatifolia individual plants fell into seven major clusters at a coefficient level of 0.35. The study revealed that DNA polymorphism detected by ISSR analysis offered a useful molecular marker for the identification of mutants in gamma radiation-treated plants. Additionally, this research demonstrated that the DNA of the hybrid (Doi Tung 554) showed a greater response in induced mutation compared with the other varieties.