Insights into deployment of DNA markers in plant variety protection and registration.

KEY MESSAGE: The efficiency of phenotype-based assessments of plant variety protection and registration could be improved by the integration of DNA-based testing. We review the current and proposed models in the era of next-generation breeding. The current plant variety protection system relies on morphological description of plant varieties. Distinctness, uniformity, and stability (DUS) assessments determine whether a new variety is distinguishable from common knowledge varieties and exhibits sufficient phenotypic uniformity and stability during two independent growing cycles. However, DUS assessment can be costly, time-consuming and often restricted to a relatively small number of traits that can be influenced by environmental conditions. This calls for the adoption of a DNA-based system which is endorsed by the International Union for the Protection of New Varieties of Plants (UPOV). This could enable examiners to deploy trait-specific DNA markers in DUS testing as well as using such genetic markers to manage reference collections. Within UPOV's system, breeders can freely use protected varieties in breeding programs. However, breeders of protected varieties may seek sharing in ownership of essentially derived varieties once it is proven that they, with the exception of a few distinctive DUS trait(s), conform to parental varieties in essential characteristics. As well as their complementary role in DUS testing, DNA markers have been known as a good replacement of morphological traits in defining boundaries between independently and essentially derived varieties. With the advent of new breeding technologies that allow minor modification in varieties with outcomes of specific merit or utility, detecting distinctness between varieties may become increasingly challenging. This, together with the ever-increasing number of varieties with which to compare new candidate varieties, supports the potential utility of using DNA-based approaches in variety description.