Studies On Parental Selectionof Tree Peonies And Genetic Performance Of Several Traits In F₁Hybrids

Tree Peonies, native to China, are famous traditional flowers and there are a few thousand cultivars cultivated around the world. For a long time, selecting the cross-combinations with better compatibility and some hybrids to achieve the goals such as extending flowering period, and rich color were the main content of peony research. In this study, P. qiui, a early blooming wild species of tree peony and P. suffruticosa’Shou An Hong’, a triploid cultivar, P. xlemoineii’High Noon’, P. xlemoineii AGH and P. lactiflora x P. xlemoinei were used in breeding. Besides, self-compatibility, fertility and breeding potential were studied in this paper, great parents and crosses conforming to the goals were selected. Observation on some characteristics such as flower types and colors of F1generatiosn was made to provide a theoretical basis. The main results are as follows:1. P. qiui was crossed with7cultivars of P.×suffruticosa Zhongyuan Group and2cultivars of P.x suffruticosa Japan Group, during which319flowers were pollinated with the harvest of4268seeds and1474seedlings, Both of the seed setting rate of open-pollinated flowers (16.76seeds per flower) and hand-pollination (13.38seeds per flower) were high. Actually, P. qiui, with strong fertility and compatibility, has great potential in tree peony breeding and can be used as an excellent maternal parent in the future. The excellent cross combination is P. qiui x’Guan Shi Mo Yu’.2.’Shou An Hong’, could produce viable male gametes, and germinations of’Shou An Hong’ were from0.00%-1.59%. Seeds could harvested in the crosses with ’Feng Dan Bai’ and P. rockii`Xiao Xin Zhuang3#’. 3.’High Noon’ was crossed with5cultivars of P. x suffruticosa Zhongyuan Group and15cultivars of P.×suffruticosa Japan Group and2cultivars of P. x lemoinei AGH as female parent. Of the1,723crosses performed, yielded a total of76seeds and3seedlings. In crosses with P.×lemoinei AGH, the setting rate (0.183seeds per flower) was significantly higher than the average setting rates in crosses with other culivars, indicating that effective materials contribute to overcoming the distant-cross incompatibility. The excellent cross combinations are’High Noon’x Ri Yue Jin’、’High Noon’x’Shou Zi’、’High Noon’×’Medora’,’High Noon’×’Colorado’.4. The average germination rate of P.×lemoinei AGH was12.57%, germination rates of ’Polyhymnia’(22.39%)、’Southern Aurora’(21.65%) and ’Adelphi’(13.29%) were high. We crossed AGH with P. lactiflora、’Martha Washington’、of P. lactiflora x P. x lemoinei as male parent, during which832flowers were pollinated with the harvest of4344seeds and691seedlings. The high setting rates (18.44,23.84and26.62seeds per flower respectively) indicate that P.×lemoinei AGH are important materials to overcome incompatibility in distant hybridization and get more Itoh hybrids. The excellent paternal parents are:’Southern Aurora’,’Adelphi’,’Medora’,’Polyhymnia’.5. When P.×lemoinei AGH was used as female parent, the seed setting rate of open-pollinated flowers (0.93seeds per flower) was significantly higher than that of hand-pollinated flowers (respectively0.06seeds per flower in2012,0.09seeds per flower in2013). The excellent cross combination is’Seid1#205’×’Ri Yue Jin’. The excellent maternal parents are:’Medora’,’Chromatella’.’Colorado’.6. When P. lactiflora x P. x lemoinei was used as female parent, the seed setting rate of P. xlemoinei AGH, P.×lemoinei,P. suffruticosa were respectively5.18,1.97,0.38seeds per flower, indicating that P. lactiflora x P. x lemoinei are important materials to overcome incompatibility in distant hybridization. The excellent cross combinations are SF1X’Hong Lou Cang Jiao’、 SF46x’Southern Aurora’, SF17x’Iowa’、SF37×’Polyhymnia’.7. Purplish red color of flowers was stronger than white color at genetic heritability, and white color didn’t belong to matroclinal heredity. When single forms ’Feng Dan bai’ were used as female parent,63.43percentage of F1were single forms, indicating that flower forms tend to be matroclinal heredity in a certain degree. The value of flower diameter and the length of flowering stems were104.77%and100.65%of parent’s, and flower diameter appeared heterosis in F1generatiosn. Characters of F1generatiosn were widely separatied and there existed special hyper-parent individualities.