The fifty-seventh session of UPOV's Technical Working Party for Fruit Crops (TWF) was held in Leipzig, Germany, from September 7 to 10, 2026, hosted by the Bundessortenamt, Germany's Federal Plant Variety Office. Chaired by Ms. Carole Dirwimmer (France), the session brought together over 120 participants both online and in person from UPOV members and observer organizations.
At the heart of the technical discussions was a question that shapes the trial of every new variety a UPOV member examines: how long a trial should run before an authority can confidently conclude its examination. Delegates weighed proposed amendments to the standard wording in document TGP/7, with constructive discussions on the different aspects of DUS examination and producing variety descriptions.
Citrus took its own thread through the session. The taxonomy for Citrus is being revised in the Germplasm Resources Information Network (GRIN) database, which will in turn allow the associated UPOV codes to be updated. The revision of scope for five Citrus groups Test Guidelines has been postponed to the next technical working party meeting in 2027 to await that work. Spain, leading the Citrus work, is exploring options to objectively assign varieties to the different Test Guidelines, particularly among mandarin-orange hybrids with overlapping morphological profiles.
Molecular techniques ran alongside the classical work. The meeting reviewed results from the 2026 survey on the use of molecular markers and tracked ongoing cooperation with OECD and ISTA on the harmonization of terms, definitions, and methods. South Africa presented on methods of observation of characteristics in fruit crops, adding to the working party's continuing exchange on how observations translate into harmonized variety testing.
A considerable slate of Test Guidelines moved forward. Full drafts for Argan, European Pear, Passion Fruit, Hazelnut, Japanese Pear, and Japanese Plum will be submitted to the UPOV Technical Committee for adoption at its sixty-second session in Geneva in October 2026. Work on Blueberry, Guava, and Persimmon continues at TWF/58, alongside partial revisions for lemons and limes, mandarin, trifoliate orange, oranges, grapefruit and pummelo.
Beyond the meeting room, delegates travelled to the Bundessortenamt's fruit testing station in Wurzen where 143 fruit examination procedures are currently underway. The group saw trials of apple, blackberry, European pear, Prunus rootstocks, raspberry, red currant, sour cherry, and strawberry, alongside variety collections of European plum, goji berry, quince, and sea buckthorn.
The session closed with a change of leadership. Ms. Carole Dirwimmer received a UPOV bronze medal in recognition of chairing the TWF from 2024 to 2026, and Mr. Yosuke ABE (Japan) is tipped to be the next chair upon endorsement from the UPOV Council.
The fifty-eighth session of the TWF will be held online from July 5 to 8 2027, with an invitation from New Zealand to host the fifty-ninth session in April 2028.
Read the full report.