| Paeonia ostii,which belongs to Paeoniaceae,is one of the famous ornamental and medicinal plants in China.It is also the main species to Jiangnan Mudan Group.Postii is a good material for breeding and researching because of its strong resistance and fruitfulness.However,there were few reports to its distribution,and the studies on the genetic diversity of P.ostii also need to be systematic.According to its area distribution,tree peony can be divided into four main variety groups,they are Zhongyuan (Central Plains),Xibei(Northwest),Jiangnan(Southern Yangtse) and Xinan(Southwest).The Jiangnan Mudan(southern Yangtse tree peony) is adaptive for rainy,moist and warm weather.As early as the old dynasties,there were many cultivars in the Group grew in Southern China.Now,the number of cultivars of this group has decreased,which seriously need systematic investigation and research.Therefore,this paper used Yangshan Nudan and Jiangnan Mudan as material,based on the method of configuration analysis with molecular data gained by ISSR and AFLP,to study.The main results were as follows:1.The field distributions of wild and cultivated P.ostii had been surveyed in Henan,Anhui,Hubei, Hunan,Gansu and Zhejiang provinces including 16 spots during 3 years.The investigation results were typical and representative.It covers all provinces in recorded except Shanxi and Chongqing.The investigation shows on-the-spot distribution range investigation of P.ostii,the level distributes in the north latitude 28°12′53.1″- 35°33′37.0″,east longitude 106°33′090″-118°01′49.0″. The wild P.ostii vertical distribution in the elevation 901-1742m scope,mainly distributes in Henan, Anhui and Hubei Province.The distribution range of cultivation P.ostii is very broad,proliferates the nation.Because the medicinal value of P.ostii,the artificial destruction was serious,which lead to serious the wild resources loss. 2.According to the analysis on Genetic Diversity of Different Populations in P.ostii,the results showed that there was an low genetic diversity in morphological characteristics of populations based on the genetic distance from0.03-0.14,different population of P.ostii could not be differentiate by the morphological characteristics.The pollen shape was different Amony and within P.ostii population indicated that there was an abundant genetic diversity in pollen characteristics of populations. Conservation genetics research by AFLP indicated that P.ostii had high genetic diversity at species level (P=93.23%,H=0.3376,I=0.5025),but relatively low levels of polymorphism at the population level (P=78.76%,H=0.2615,I=0.3942);the coefficient of genetic differentiation among populations(Gst) was 0.1991 and if showed that 19.91%of the total genetic variation among populations while the rest 80.09%within populations;the level of gene flow(Nm) was estimated to be 2.0116＞1.Henan Baotianman and Anhui Bozhou populations had the closest relationship,and the geographic distance was not positively correlated with genetic distance.3.In history,the distribution of Jiangnan tree peony cultivars distributed covered from South Dynasty in Yongjia to the Tang Dynasty in Hangzhou,the Song Dynasety in eastern of Zhejiang and Wuzhong area (now Suzhou),and then the Ming and Qing Dynasties in JiangSu,Zhejiang,Shanghai.The number of cultivars showed the trend of dynamic growth with fluctuation trend.And now,Jiangnan Mudan Group presently mainly distributed in Shanghai,northwest of Zhejiang,south of Jiangsu,southeast of Anhui,the secondary distribution was north-western of Hunan.4.The tree peony cultivars of Jiangnan Mudan Group mainly meaned to the P.ostii and its traditional cultivars.The existing cultivars had good adaptability to the climatic conditions in Jiangnan area.But due to the moisture climatic characteristics and the sticky soil of Jiangnan regions,as well as the biological characteristics of tree peonies,the number of tree peony cultivars was deficient in Jiangnan area.It was unitary in flower color and shape.The number of actual cultivars was less than 20, including 'Fengdan','Xishi','Fenlian','Yulouchun','Changhong','Huhong','Yuhong','Quehao', 'Meihong','Sixuan','Qingluo','Yunfang','Heilouzi','Xiangxizi','Xiangxifen','Xiangdan','Yulou', 'Fengwei','Yanchenghong','Yancbengfen'.According to morphological and molecular evidence,to resolve the problem of synonym:'Xishi','Fenlian','Yulouchun' were merged and called 'Yulouchun'; 'Changhong','Huhong','Yuhong','Quehao','Meihong','Sixuan','Qingluo',were merged and named 'Huizi';'Yulou','Fengwei',were merged and called 'Yulou'.Then,there were only 11 tree peony o cultivars in Jiangnan area after reorganization.5.The resources of ancient tree peony cultivars in Jiangnan area was richful.On-the-spot investigation, the ancient tree peony cultivars mainly distributed in 27 places of Shanghai,Zhejiang,Jiangsu,and Anhui Provinces.They were distributed in the private courtyard and old temples.There were mainly four cultivars,'Yulouchun',the purple-red flower(nameless),'Heilouzi' and 'Yanchenghong'.It explained that the history of Jiangnan Mudan was glorious.Some of the ancient tree peonies appeard weak or died.Rejuvenation and conservation,protection and effective utilization were necessary for ancient tree peony.6.According to the studies,the possible origin of Jiangnan Mudan Cultivar Group,mainly directly came from the tree peony cultivars form Zhongyuan,Xinan and Xibei Group.P.ostii had the indirect participation the formation of tradition cultivars.The strategies of breeding Jiangnan Mudan were proposed.Firstly,the breeding aim of Strong resistance and high value was ascertained.Secondly,using P.ostii and existing wild species and the ancient traditional tree peony from Jiangnan and other excellent heat resistance resources,such as P.×suffruticosa Japan Group,P.×suffruticosa Tianpeng Group,P.rockii Gansu Grou,through hybridization and other means,to breed the excellent cultivars for Jiangnan Area.This study could be a base theory for protecting and use the germplasm resourses,identifying relationship of different cultivars from Jiangnan Area,selecting and breed excellent cultivars. |
