A Study On The Crossing Compatibility And Hybrid Abortion Of Paeonia

Peony (Paeonia×suffruticosa Andr.) is a Chinese special flower and medicinal plant, their wide distribution, cultivation has a long history in China since ancient times deeply loved by people of all nationalities and the world. For a long time, cultivar improvement through breeding works has been the main content of peony research and production. In this study, according to the breeding objectives, making the full use of domestic and international resources, hybrid parents were chosen to plan cross-combinations and a great deal of crosses were done. Meanwhile, the flowering habits and exudate secretion of the main female parents were observed in order to improve crossing efficiency.And hybrid abortion happened in distant crosses was studied preliminarily. The main results are followed:(1) In this study,26 types of hybridization were set,416combinations were crossed, a total of 4,939 flowers were pollinated,56,793seeds and 19,314seedlings were harvested.; 43,937 seeds and 19,240 seedlings were obtained from close hybridization within subsect. Vaginatae; 2,095 seeds and 37 seedlings were harvested from Infra-subsectional hybridization between subsect. Vaginatae and subsec.delavayanae; 761 seeds and 37 seedlings were harvested from inter-sectional hybridization between Sect. Moutan and Paeon.(2) Cross compatibility varied with different types of hybridization. Within close hybridization in subsect. Vaginatae, the crosses were very compatible, the average setting was 18.70 seeds per flower. When the female parents of infra-sectional close hybridization had small individual differences, average setting was mostly relative to the flower type of male parents. The average setting of infra-sectional was 1.83 seeds per flower, which was obviously lower than the average setting of close hybridization within subsect. Vaginatae. So the result can show this type of hybridization was incompatible to some extent. Cross compatibility of inter-sectional hybridization was extremely low, the average setting of it only 0.52 seeds per flower. Discovering and using the novel parent resources with strong fertility for the distant crosses was the key point to make a breakthrough in this type of hybridization. And this study had further verified that P.veitchii can be used as good resource for inter-sectional hybridization in Paeonia.(3) With P.ostii'Feng Dan Bai'as female parent and P.veitchii as male parent, after pollination, the ovules at different periods of this cross were taken for microscopic observation, which found that the hybrid embryo development mainly stopped in the original stage and couldn't grow to mature stage. The main reason of embryo abortion may be attributed to the failure of the free nuclear endosperm which provided nutrition for the original embryo.