S05 - Session O1 - Modified atmosphere storage of cut peony flowers to extend the sales period

Authors: Annelies Christiaens *, Liesbet Blindeman, Lieven Van de Vondel, Peter Ragaert, Frank Devlieghere, Bruno Gobin, Marie-Christine Van Labeke

Herbaceous cut peony ( Paeonia lactiflora Pall.) has a limited marketable period due to seasonal production. A qualitative storage period can extend the sales period. In three consecutive years, cultivars 'Sarah Bernhardt' (SB) and 'The Fawn' (TF) were allowed to flower at room temperature immediately after harvest or after dry storage for 6 and 10 weeks under normal atmosphere and modified atmosphere at 2°C. Atmosphere was modified using a commercial pallet box (Janny MT module) which resulted in an average concentration of oxygen and carbon dioxide of approximately 3%. During storage ethylene accumulated in the pallet box, while under normal atmosphere ethylene levels remained low. Disease incidence ( Botrytis cinerea ) increased during storage and was higher in 2021 (a cold and wet spring) compared to 2020 (a warm and dry spring). After 10 weeks of storage, disease incidence on the flowers was significantly less under modified atmosphere compared to normal atmosphere. A postharvest treatment before storage (in 2021) with 30% pyrimethanil as fumigant significantly decreased Botrytis incidence. However, the treatment was phytotoxic. Even though the maximum efficiency of photosystem II (F v /F m ) decreased significantly during storage and was significantly lower under modified atmosphere, flower opening, and vase life duration was not equally affected. Vase life duration of SB was shorter after storage. However, flower opening was improved after 6 weeks of storage and not different after 10 weeks of storage for SB compared to non-stored flowers. Flower opening of TF was not different after 6 weeks and poorer after 10 weeks of storage compared to non-stored flowers. The vase life duration of TF was not significantly affected by cold storage. The storage atmosphere had no significant effect on flower opening and vase life duration in 2019 and 2020. In 2021 vase life was shorter for flowers stored under normal atmosphere due to supplemental Botrytis infestation during vase life.