S05 - Session P1 - Induction and mitigation of BPP in greenhouse cut rose

Authors: Jihyeon Seo *, Wan Soon Kim

To understand the bent peduncle phenomenon (BPP) in greenhouse cut roses, we examined if heat shock during floral development induces BPP and if phylloid sepal removal mitigates it. We treated cut roses 'Beat' by heat shocks of 30℃, 35℃, or 40℃ for 72h at three flowering shoot development stages: S1 (before floral bud development), S2 (early floral bud formation, not enough floral organ differentiation), S3 (after floral organ differentiation). As results, BBP was induced 23.1%, 40%, and 15% by heat shock temperature 30℃ to 40℃ at S2, 20.0%, 25%, and 0% at S3, and 0%, 9.1%, and 11.8% at S1, respectively. Removing a phylloid sepal in BBP stems was examined to six cut roses 'Propose', 'Beast', 'Revue', 'Ocean Song', 'Iguana', and 'Legato' with BPP symptoms. The phylloid sepal removal treatment showed the cultivar-specific effect, with the restoration of bending in two cultivars, 'Legato' and 'Revue', but not in the others. Conclusively, BPP induction would depend on heat shock around 35℃ during floral organ differentiation, and a phylloid sepal seems to cause worsening BPP symptoms.