The Technical Working Party for Ornamental Plants and Forest Trees (TWO) held its 57th session in Roelofarendsveen, Kingdom of the Netherlands, from March 31 to April 3, 2025, bringing together experts and stakeholders to develop standards and enhance collaboration in DUS (Distinctness, Uniformity and Stability) testing.
A standout moment of the session was the presentation from a French expert on using Genotyping-by-Sequencing (GbS) to support DUS testing in Hydrangea. The study introduced a targeted use of SNP markers—20 to confirm species and 40 to distinguish H. macrophylla varieties. Promising results showed strong correlations between genetic markers and traits like flower color, paving the way for more efficient testing and up to a 33% reduction in trial sizes.
Participants also reviewed six Test Guidelines covering a range of ornamental plants, including Ginkgo, Magnolia, and Zantedeschia, alongside a partial revision for Dianthus.
Read the full report here.