Development of new guidelines for the conduct of tests for distinctness, uniformity and stability of Japanese quince (Chaenomeles Lindl.) cultivars

Purpose. To develop guidelines for the conduct of tests for distinctness, uniformity and stability of Chaenomeles cultivars.Results. Species of the genus Chaenomeles are valued as ornamental, fruit and medicinal plants. Plant Variety Database (PLUTO) includes ornamental and fruit Japanese quince varieties registered in the European Union, China, Latvia, the Netherlands, Poland, Russia, Ukraine and Japan. Neither CPVO protocols nor UPOV guidelines have been developed for Chaenomeles, but in the European Union, China, Russia and Ukraine the four national guidelines for the DUS-testing of Japanese quince varieties were published in 2003–2016. Each of them takes into account, respectively, 46, 31, 51, and 31 traits. They differ in the selection of characteristics which should always be examined for DUS and for grouping of varieties. Both flower and fruit characteristics of are the main for distinguishing Japanese quince varieties, which is facilitated by strong variability in the coloration of petals and fruits, the fruit shape and fruit weight, etc. Existing guidelines differ meaningfully in the description of these and other characteristics. Several different approaches to filling and improving the guidelines have been proposed according to the basis of Chaenomeles cultivars and species collection study and own breeding experience.Conclusions. The new guidelines contain 42 appropriate characteristics of plant morphology, shoots, thorns, leaves, flowers, fruits, seeds as well as phenology and can be used for the conduct of tests for distinctness, uniformity and stability of all Chaenomeles cultivars.