Abstract:

On the basis of building the Jiangnan Peony Planting Resource Garden, inter-cultivars hybridization was carried out between the Jiangnan ornamental peony variety with strong flood tolerance and the oil peony variety Fengdan, attempting to introduce excellent flood tolerance genes into oil peony varieties to cultivate new oil peony varieties with strong flood tolerance. The main hybrid combinations are as follows: Dafugui×Fengdan, Yulouchun×Fengdan, Yipinhong×Fengdan, Hongfurong×Fengdan. The results showed that different hybrid combinations had different seed setting rates, germination rates, and waterlogging tolerance of hybrid seedlings. The seed setting rates of the four hybrid combinations were all above 70%, with Yulouchun×Fengdan achieving a seed setting rate of 85%. The germination rate of seeds was between 60%-80%, and the hybrid combination Yulouchun×Fengdan achieved a seed germination rate of 80%. Compared with the maternal parent of Fengdan, the waterlogging tolerance of the hybrid seedlings has been improved. The physiological indicators of waterlogging tolerance, such as sucrose synthase (SS),α-amylase (RAMY), alcohol dehydrogenase (ADH), and pyruvate decarboxylase (PDC), were significantly higher than those in the control Fengdan, with the most obvious improvement observed in Yipinhong×Fengdan, followed by Yulouchun×Fengdan. The results of this study have obtained a new germplasm of Fengdan that is tolerant to waterlogging, providing a variety resource for the southern regions with more rainfall, especially the Jiangnan region. It fundamentally solves the problem of waterlogging faced by oil peonies and provides favorable resource guarantees for industrial development of oil peonies.

Key words: Paeonia ostii cv. Fengdan, hybridization, seed setting rate, germination rate, waterlogging tolerance