Cheng, F., Zhong, Y., Long, F., Yu, X.

Observations on twenty Chinese herbaceous peony (Paeonia lactiflora) cultivars under both ambient and forcing conditions revealed seven stages of plant development from dormancy release to anthesis. The flowering ability was evaluated in these cultivars under forcing conditions, and only five of them were identified as suitable for forcing. ‘Da Fu Gui’ was selected to study the effects of chilling and gibberellin (GA3 ) application on growth and flowering under forcing. Prior to forcing, four chilling regimes (0, 3, 4, and 5 weeks at 0–4 °C) in combination with 0, 200, and 500 mg/L of GA3 were applied. The results showed that all the chilling promotes dormancy release and plant growth, while GA3 application significantly accelerates sprouting and growth, and advances the flowering of the peony plants. However, no significant difference was found between 200 and 500 mg/L GA3 . Stem height, flower size, and flowering rate were positively affected by both chilling and GA3 , while leaf extension (maximum width of foliage) was influenced only by GA3 . A GA3 concentration of 200 mg/L was found to be the optimal for forcing ‘Da Fu Gui’ peony chilled at 0–4 °C for 4 weeks.