DUS testing for plant variety protection: Some researchable issues

Abstract

In order to implement effectively Protection of Plant Varieties and Farmers’ Rights Act, 2001 testing of new varieties for Distinctiveness (D), Uniformity (U) and Stability (S) is essential. Based on field and laboratory trials along with the most similar variety a new variety is compared for the characteristics which describe the variety. Distinctiveness assessment of a new variety apparently looks easy but actually it is not so particularly in case of crop species maintained /reproduced through often cross pollination and cross pollination owing to presence of plants with varied expression in some characteristics. Similarly, uniformity assessment of a variety ensures its genetic purity. The crop specific DUS test guideline has been developed and followed for plant variety assessment to register a new variety. Further there is enough scope to comprehend the guidelines for the benefit of plant variety examiners. To make the comparison scientific and valid some statistical procedures are used. Plant varieties differ genetically and the differences are expressed in the form of phenotypes (characteristics). The level of difference depends not only on the genetic constitution of the characteristics but also on the sample size, level of confidence, reject numbers etc. These are required to be studied in each plant species keeping in mind the overall variation available among the varieties in a plant species and easiness in the registration process. In view of influence of growing environment on the quantitative characteristics there is need to identify a separate set of example varieties for proper description and assess distinctiveness of new varieties for its protection.