Identification of floral fragrance components in an F1 population derived from Paeonia ostii 'Fengdan' × P. suffruticosa 'Chunguihuawu' Cross

Tree peony (Paeonia suffruticosa Andr.) is a unique aromatic plant famous for its huge flowers, bright colors and strong fragrance, having high ornamental, medicinal, and edible value. Research on tree peony's flower fragrance has mainly focused on the comparative analysis among its varieties, leaving the inheritance of aroma compounds in this plant an overlooked area of study. Here, the volatile components of flowers at three different flowering stages of the light fragrance-type cultivar P. ostii 'Fengdan' and the strong fragrance-type cultivar P. suffruticosa 'Chunguihuawu', as well as the half-opening stage flowers of 109 F1 progeny, were collected and characterized in-depth by dynamic headspace sampling technique combined with gas chromatography-mass spectrometry (GC-MS). Diverse profiles of volatiles that included alcohols, esters, aldehydes, terpenes, benzenes, and hydrocarbons were identified from the evaluated accessions. These results revealed that the volatile components and content of parents were significantly different, and that hybridization generated more complex volatile components. Most volatile compounds in the hybrids, especially the main aromatic components, existed in at least one of the parents, being characterized by intermediate or transgressive inheritance for the floral trait; this demonstrated that volatile compounds can be inherited from parents to progeny. Further, seven de novo aroma compounds—those present in progeny yet absent in their parents—were found in progeny. This study preliminarily clarified the segregation performance of aroma traits in tree peony hybrids, which might provide a theoretical basis for selecting breeding parents and the breeding of new varieties for aroma traits.