Usage of microsatellite markers for characterization of polyploids: a case study in reference to hexaploid bamboo species

Microsatellite markers are most valuable tools for characterization of plant genetic resources or population genetic analysis. Since they are codominant and allelic markers, utilizing them in polyploid species remained doubtful. In such cases, microsatellite markers are usually analyzed by treating them as dominant marker. In the current study, it has been showed that despite of losing the advantage of co-dominance, microsatellite markers are still powerful tool for genotyping of polyploid species because of availability of large number of reproducible alleles per locus. It has been studied by genotyping of nineteen sub populations of Dendrocalamus hamiltonii (hexaploid bamboo species) with seventeen polymorphic SSR primer pairs. Among these, ten primers gave typical banding pattern of microsatellite marker as expected in diploid species but rest seven gave unusual pattern i.e. more than two bands per locus per genotype. In such case genotyping data are generally analyzed by considering as dominant markers. Given these facts, data were analyzed in both ways as dominant and codominant. All the seventeen primer were first scored as non-allelic data and analyzed; later ten primer pairs giving standard banding pattern were analyzed as allelic data and the results were compared. The UPGMA clustering and genetic structure showed that results obtained with both the data sets were very similar, and therefore the SSR marker could be utilized to characterize polyploid species by considering them as dominant marker. The study is highly useful to widen the scope of SSR markers applications and beneficial to the researchers dealing with polyploid species.