Morphological descriptors for dus testing of potato varieties

Before a variety is registered as a cultivar and/or granted Plant Breeder's Rights, its distinctness, uniformity and stability (DUS) is tested using morphological characters (descriptors). In the present study, we examined the comparative effectiveness of the morphological descriptors of potato proposed by the International Union for the Protection of New Varieties of Plants (UPOV), the International Board of Plant Genetic Resources (IBPGR) and the Central Potato Research Institute (CPRI), India. Observations on 89 descriptors proposed by various organizations were recorded on 100 potato genotypes by four potato breeders independently for two years. Mean squares due to year, genotype, breeder and genotype x year interaction were significant for majority of the descriptors, whereas genotype x breeder interaction were significant for only five descriptors. The coefficients of variation due to error in recording the various descriptors ranged from 1.63 to 27.97%. Based on the precision with which various descriptors could be recorded, and year to year and breeder to breeder variation in recording these descriptors, 39 descriptors were found suitable for DUS testing of potato varieties. These descriptors represented all the three sources included in the study. Some of the original descriptors, however, were modified by clubbing the overlapping classes so that revised classes were more distinct from one another with reduced chance of a genotype being misclassified.2