Distant Cross-breeding In Tree Peony And Identification Of Some Hybrids By AFLP

The tree peony is one of the world famous flowers. For a long time, the improvement of varieties and breeding work have been the main content of peony research and production. Distant cross-breeding of tree peony is a main method of cultivar improvement at present and for quite a long time in the future. Further more, the cross-combination with better compatibility is the key factor of success in distant cross-breeding of tree peony. In this study, some cultivars and species of tree and hebaceous peonies were selected as parents which, with good traits, were fertile in various cross-combinations and some of hybrids seedlings were identificated by AFLP(Amplified Fragment Length Polymorphism). Selecting the cross-combinations with better compatibility would provide effective way to overcome the incompatibility of distant cross-breeding in tree peony, and some hybrids gained from the study also would provide the probability to achieve the goals such as extending flowering period, reblooming a year and rich color. The main results are as follows:1. The experiment of distant hybridization had been conducted with 29 cultivars or species, including intersubsectional hybridization in Sect. Moutan and intersectional hybridization between Sect. Moutan and Sect. Paeon. The crossing experiment with 1084 flowers and 48 cross-combinations produced 1715 seeds, from which 534 seedlings were got in the following year. Setting percentage varied with different cross-combinations. In most cases, the crosses with herbaceous peony 1# , 2# and P.veitchii as female parent and'Golden Era','Souvenir de MaxineCornu','Renown'and'Viking Full Moon'as male parent had a higher setting percentage and could overcome the incompatibility of distant cross-breeding between Sect. Moutan and Sect. Paeon. The setting percentage was higher between P.ostii'Fen Dan Bai'×'High Noon', P.rockii×'High Noon', as a result, the incompatibility of distant cross-breeding in intersubsectional hybridization of Sect. Moutan was overcomed. 2. The molecule identification of 22 offspring from the cross-combinations P.rockii×'High Noon'by AFLP showed that most offspring were real and mother-closed hybrids. The offspring had different AFLP bands from their parent which meaned that the offsping not only inherited the characteristics of parents, but also had new variation.3. The compatibility of P.rockii×'High Noon'was higher and most offspring produced by the combination were real hybrids identified by AFLP. Consequently, this cross-combination had more potential and could be adopted widely in the breeding of tree peony.