The present-day Plant Variety Protection (PVP) is dependent on morphological characters that are used for Distinctness, Uniformity, Stability (DUS) testing. The objective of this study is to asses the utility of Simple Sequence Repeats (SSR) in distinguishing varieties and variants as opposed to clones and species. In this study, we used 16 SSRs for fingerprinting 48 carnation genotypes. As expected in a polyploidy, the number of alleles per locus ranged from single to four. Clustering based on morphological characters could clearly distinguish varieties, variants, species and interspecific hybrids, whereas the clones remained identical. Clustering based on SSR alleles could separate the species and interspecific hybrids with similarity ranging from 0.53 to 0.9. A genetic distance of 0.05 could be noticed between clones.

Plant Variety Protection (PVP) is of critical importance worldwide to encourage the development of new varieties and to provide plant breeders rights. To grant protection to a newly proposed variety, it is essential to establish the distinctness and true identity of the new variety over the existing ones. The uniqueness of a variety is established by morphological tests for Distinctiveness, Uniformity and Stability (DUS), for which the International Union for the Protection of New Varieties of Plants (UPOV) has provided guidelines in case of most economically useful plant species. These tests are constrained by time and space, besides, these tests are often made by subjective decisions. In this context, to make the tests more objective, molecular markers are always thought of as possible alternative and as supportive to morphological DUS testing. Of the several molecular markers available, Simple Sequence Repeats (SSR) are the most acceptable to distinguish varieties, as they are highly polymorphic. Contradicting reports regarding the utility of SSRs in distinguishing the varieties exist. Clones and mutants remained identical, as estimated by SSR (Rusanov et al., 2005). A high rate of intracultivar SSR variability was reported in clones in various crop species. SSR loci are known to have a high rate of mutation per locus per generation, making it ideal for establishing the distinctness. At the same time, the high rate of mutation itself may be a cause for concern failing to establish the uniformity within the variety. Appropriate statistical analysis plays a significant role in deciding the controversies in such cases to establish uniformity within a variety and distinctness between varieties.

In flower crops, generally flower color is considered as the easiest parameter to distinguish among varieties. However, it is possible that two similar flowers may be resulting from completely different cross combinations. In such cases, the SSRs become useful, provided they give rise to a lot of variations that are not detectable by comparison of morphological characters. The critical question, however, is the threshold limit for accepting the distinctness as the true distinctness for giving the status of a new variety. The present study attempts to illustrate the possibilities and limitations of SSR fingerprinting in establishing the distinctness and its utility in protection of plant varieties.

Biotechnology Journal, Stress Adaptation of Bacteria, Extremophiles, Bacterial Adaptation, Cytosolic Components, Denature Cellular Proteins, Reactive Oxygen Species, Monounsaturated Fatty Acids, Ultraviolet Radiation, Environmental Stress, Stress Management, Biological Systems, Cellular Economy.