Center for Seeds and Seedlings, NARO

DUS Growing Test

DUS growing test

The Plant Variety Protection and Seed Act provides the plant variety registration system for protection of plant breeders' rights to promote breeding new varieties. Japan is a member state of the International Union for the Protection of New Varieties of Plants (UPOV), an international organization aiming to protect new plant varieties, and operates its plant variety protection system in harmonization with other member states.Under the plant variety registration system in Japan, NCSS conducts DUS (Distinctness, Uniformity and Stability) growing test to provide data to clarify whether candidate varieties are new ones or not for the examination by Intellectual Property Division of Ministry of Agriculture, Forestry and Fisheries (MAFF).In DUS growing test, candidate varieties are cultivated on fields or in greenhouses and compared with similar existing varieties (reference varieties) and morphological characteristics (colors, shapes, size, etc.) and physiological characteristics (tolerance to diseases, etc.) are evaluated.

  • Distinctness: New varieties should be clearly distinguishable from any other existing varieties.
  • Uniformity: Individual plants of new variety should be sufficiently uniform at the same propagation stages.
  • Stability: Characteristics of new variety should be stable through repeated propagation.

To conduct DUS growing tests appropriately and efficiently, NCSS is taking every measures as follows:

  • Development of technical manuals for cultivation, examination of morphological characteristics (color, shape, etc.) and physiological characteristics (tolerance to pests and diseases, particular components etc.)
  • Collection and conservation of reference varieties, including standard varieties, and development of their database .
  • Data collection of characteristics of newly introduced plant species/genera into Japan for facilitation of development of new DUS Test Guidelines by Intellectual Property Division, MAFF.
Changes in the number of variety registration applications and DUS tests
Number of applications for new plant variety registration 1,112 1,013 1,117 1,162 1,027 979 941 988
Number of DUS growing tests 719 762 678 741 805 831 733 653

Naktuinbouw and NCSS have established Calibration Manuals for DUS test


The Netherlands Inspection Service for Horticulture (Naktuinbouw) and the Center for Seeds and Seedlings, NARO (NCSS) have established Calibration Manual for DUS test. Calibration Manuals, which include many photographs explaining how to observe and measure characteristics of varieties will be easy-to-understand reference material for users from these countries. This joint activity will result in 11 calibration manuals.