Safeguarding, evaluating and valorizing fruit tree genetic resources in Belgium: Insights from nearly half a century of unsprayed orchard management

In response to the rapid genetic erosion threatening Belgium's fruit tree cultivar heritage, the Walloon Agricultural Research Centre (CRA-W, Gembloux, Belgium) initiated nationwide prospection campaigns in 1975 with support from citizens. These campaigns aimed to collect and conserve the country’s highly diverse fruit tree genetic resources (FTGR), including historically significant amateur-bred and landrace cultivars, for future breeding efforts. Since then, the CRA-W has maintained a diverse collection – primarily apples (1,629 accessions) and pears (1,198 accessions), but also cherries (355 accessions), plums (236 accessions), grapes (98 accessions), and peaches (29 accessions) – in ex situ unsprayed repository and experimental evaluation orchards. This approach makes it possible to assess these cultivars for multiple traits related to their tolerance and adaptability to biotic and abiotic stresses. This long-term evaluation method enables the identification of numerous quantitative traits and their impact on robustness and stress tolerance. Moreover, CRA-W has actively sought ways to promote the sustainable use of FTGR through partnerships with public institutions, private stakeholders and citizens. One key initiative was the gradual establishment of a nursery network governed by a participatory fruit tree quality charter, coupled with a traceability system for high-quality propagation material. This initiative led to the release of 33 well-performing heritage cultivars, notable for their sufficient robustness and disease tolerance, for use in both amateur and professional orchards. A decade later, a dedicated apple pre-breeding and breeding programme was launched to harness the extensive FTGR collection as a source of quantitative disease tolerance, robustness and quality traits.