About 80 experts on ornamental plants and forest trees convened online from July 6 to 9, 2026, for the fifty-eighth session of UPOV's Technical Working Party for Ornamental Plants and Forest Trees (TWO), chaired by Ms. Hilary Papworth (United Kingdom).
For plant variety examiners, few characteristics are trickier to pin down than color. A chrysanthemum petal may require examiners to compare multiple color charts to accurately determine a color. That challenge sat at the heart of the session's technical discussions, as delegates explored how emerging technologies can increase efficiency of the assessment of ornamental varieties.
China presented an image analysis method for testing chrysanthemum petal color, developed with a purpose-built calibration card to reduce variation across equipment. The Kingdom of the Netherlands shared results from testing different color scanners on flowers, tools that turn what the eye sees into an objective measurement, while Japan reported early progress with a spectrophotometer for the same purpose, and invited other UPOV members to join the work.
Beyond color, the TWO advanced work on a full slate of Test Guidelines. Drafts for Ginkgo, Helleborus, Magnolia, the combined revision for Rhododendron and Azalea, and the revision of Zantedeschia will be submitted to the UPOV Technical Committee for adoption at its sixty-second session in Geneva in October 2026. Work on Alstroemeria, Forsythia, Lotus, Ornamental Apple, and Torenia continues at TWO/59, alongside a partial revision for Aloe.
The session also marked a handover of leadership at the TWO. Ms. Hilary Papworth was thanked for chairing the working party from 2024 to 2026 and was awarded a UPOV medal in recognition of her service. The TWO agreed to propose Ms. Stéphanie Christien (France) as the next chair, for recommendation to the Council.
At the invitation of Japan, the fifty-ninth session of the TWO will be held in Yokohama, Japan, from June 8 to 11, 2027.
Read the full report.