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Figure 2-1 The medical bamboo slips of Wuwei in the Han Dynasty

2. The Origin of Cultivars

The tree peony cultivars come from the wild species. Meanwhile, the cultivars are the products of horticulture industry at a specific stage of development. The formation of tree peony cultivars and cultivated variety group is associated with the historical, cultural, and socioeconomic backgrounds and abides by the related natural law.

2.1 The Origin of Cultivars and the Cultivated Variety Group

2.1.1 Early Application of the Wild Species and Origin of Cultivated Variety Group

Historical Investigation of Early Application

Tree peony is not only a medicinal plant also an ornamental plant. We don' t know when the earliest domestic cultivation began because of lack of historical record. In the early literatures before the Qin Dynasty (221-206 BC), tree peony and herbaceous peony were not separated and generally shared in one name "peony" (Shaoyao in Chinese). About 3,000 years ago, the herbaceous peony was recorded in two books Shan Hai Jing and Shi Jing respectively. The herbaceous peonies were planted in the garden in the first year of Dixiang, about 4,000 years so far. It is worthy of believing to a large extent, although it is possibly a legend. The original cultivation history of tree peony should be different that of the herbaceous peony.

The flowers of tree peony are big and fragrant. Therefore, in the distributional areas local people often dig them from mountain forest and plant in the yards as an ornamental. Such primal introduction and manual domestic manner should origin very early. Based on the archeological records, in the Han Dynasty (206 BC-AD 220), people had understood the different medicinal values of the tree peony and the herbaceous peony and could definitely distinguish between them. In 1972, the early medical bamboo paper of the Dong Han Dynasty (AD 25-220) (Fig. 2-1) was unearthed on the dry beach slopes of the northern piedmont (10 km away from the city of Wuwei) of Qilianshan, Gansu Province. Two slips (No. 11, 12) of which recorded a prescription to cure "Xue Yu Bing"(blood stasis) with tree peonies. Four slips (No. 46,47, 55, 56) recorded the prescriptions to treat "Fu Liang Guo Nong"and other diseases with the herbaceous peonies.

Over 30 medical prescriptions are reserved in the medical bamboo slips of Wuwei in the Han Dynasty. Approximate 100 medicaments were enumerated in prescriptions. These bamboo slips are a summarization of medicine-practicing experience written by some doctors in the Dong Han Dynasty.

It is worth noting the following two points. Firstly, the medical bamboo slips were written after the book Shen Nong Ben Cao Jing. Because 69 kinds out of 100 medicaments recorded in the medical prescriptions of bamboo slips were also seen in Shen Nong Ben Cao Jing, 11 kinds seen in Ming Yi Bie Lu, the other 20 kinds not included in these two books. In the aspect of medicament,

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Figure 2-2 Luo Shen Fu Tu by artist Gu K.Z. in the Dong Jin Dynasty (part)

obviously, the medical bamboo slips of Wuwei involved some new contents in contrast to Shen Nong Ben Coo Jing, and proved the tree peony and the herbaceous peony had been definitely distinguished. Secondly, one of medical bamboo slips of Wuwei specifically recorded medicine price, it indicated that the tree peony and the herbaceous peony have been used as a medicament with some economic values.

Inchoation of Ornamental Planting and Formation of Early Primal Cultivars

Inchoation of Ornamental Planting It took a long time for switch of tree peonies from a medical plant to an ornamental plant. At present, most people agree that ornamental planting of tree peony should begin in the Dong Jin Dynasty (AD 317-420). It is principally based on the evidence in a painting of Luo Shen Fu Tu which is a masterpiece made by Gu K.Z. (about AD 345-409), a famous artist. In this picture, the tree peonies were blooming on the bank of the Luo River (Fig.2-2).

Additionally, tree peonies in yard occurred in other works of Gu. K.Z. Therefore, tree peony was already ornamentally planted about 1600 years ago.

Formation of Early Primal Cultivars of Tree Peony People noticed the variation of tree peonies when they grew the tree peony as an ornamental plant. The early cultivars began to be established when people intentionally selected the variations and reproduced them by artificial vegetative propagation. This period should be from the Dong Jin Dynasty (AD 317-420) to the Sui Dynasty (AD 581-618). In the Tang Dynasty, tree peonies were very popular in Chang' an (now Xi' an City).

In the Bei Song Dynasty, in Luo Yang Mu Dan Ji (Tree peony of Luoyang, abbr. Ou Pu), Ouyang X. not only clearly recorded the names, derivation, and ornamental values of some famous cultivars during that time, but also pointed out the economic values of excellent cultivars. For instance, tree peony 'Wei Hua' "One woodchopper firstly found ' Wei Hua' in the mountain of Shou' an and then sold it to a person named Wei. Both residence and pond of Wei are very big, according to the legend, when ' Wei Hua' began blossoming, the people, who want to see flowers, must pay over ten coppers then can go to the flower house by boat. Wei made

one thousand strands of coppers per day". Thereafter, Ouyang X. talked about 'Yao Huang':"For 'Yao Huang', five thousands coppers per cion. Order in autumn and pay in coppers after seeing the flower in the next spring." "At the beginning of 'Wei Hua' open to the public, its cion was valued at five thousands coppers, now it was still worth one thousand coppers". Besides Ou Pu, in the other records, the economic values of some excellent cultivars were also involved when describing the ornamental values of tree peony varieties. Thus, as an important productive element, variety has been highly associated with market economy since the Tang Dynasty.

2.1.2 The Origin and Evolvement of Chinese Tree Peony Cultivar-groups

Chinese tree peonies were introduced to the royal gardens from mountainous regions and common people' s yards, they then diffused to the surrounding areas from the capital city or cultivation center. With the development of social politics, economy and culture, several developing climaxes appeared in Chinese history and tree peony have been gradually formed several cultivar-groups and cultivar-subgroups with different characteristics. The process of cultivar-groups formation has the following traits (Li J. J. 2002, 1998, 1992, 1989).

The Multiregional Origin of Tree Peony Cultivars

The origin of tree peony cultivars should include both the origin of early primal cultivar and the formation of cultivated cultivar-groups. In this way, the meaning of multiregional origin is that, firstly, the early primal cultivars rooted in many distributional areas; secondly, cultivar-groups have several centers of origin.

Wild tree peonies are widely distributed in China. Early primal cultivars directly came from the introduction and domesticated cultivation of wild tree peony plants in distributional regions. According to the literature records in the Tang and Song Dynasty, the regions of origin include Fenyang and Wenshui, Taiyuan, Shanxi Province; Yichuan, Yan' an, Longxian, Shaanxi Province; Zibo, Shandong Province; Shaoxing, Zhejiang Province; Chuzhou, Hexian, Huizhou, Yixian, Shexian, Anhui Province; and Tianshui, Gansu Province, and

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so on. They also probably involves Yixian, Hebei Province, but it is still under dispute. The formation of cultivar series (groups) began in Xi' an, Shaanxi Province and Luoyang, Henan Province. The time of formation should be in the Tang and Wudai Dynasty. The formation of other regions of origin includes Wuxian, South Jiangsu; Hangzhou in Zhejiang; Chengdu and Pengzhou City in Sichuan Province. The formation of the cultivar-group in these areas began in the Song Dynasty. The Middle Gansu is also one of the original centers of cultivars (groups), however the formation of cultivar-group is relatively late in the Ming and Qing Dynasty.

The Single and Multiple Origins of Tree Peony Cultivars

As for the origin of variety, the formation of tree peony cultivar comes from mono-origin and multi-origin (hybrid origin), or from hybrid origin by hybridization between varieties and cultivar-groups from mono-origin. The early primal cultivars are mainly of mono-species origin, occasionally of multi-species origin. The formation of cultivar-groups is of either mono-origin or multi-origin. The protospecies (ancestor), which participated in the formation of Chinese tree peony cultivars, is considered principally P. jishanensis and P. rockii, secondly P. ostii and P. qiui of the Subsection Vaginatae. Up to now, it has not been found gene flow between P. decomposita and cultivated groups (Li J.J. 1998; Yuan T. 2002). In the Subsection Delavayanae, P. delavayi, P. lutea and P. ludlowii are used in the breeding of the Occident cultivar group, here the cultivars produced by hybridization between P. delavayi, P. lutea and P. suffruticosa, were introduced to China from Japan and America respectively. Pure cultivar series come from the cultivar-groups of mono-origin, such as "Feng Dan" series, it come out of Jiangnan cultivar group from development and evolution of P. ostii; the majority of Xibei (NW) cultivar group, which were developed and evolved from P. rockii. However, these cultivar groups also have a trend in multiple developments. Multiple origin of cultivar groups formed hybrid series. These viewpoints have been supported by the results of palynological investigation and other studies subsequently (Yuan T. et al. 2002; 2000). The factors of leading to multiple origin and hybrid origin are that: Firstly, several wild tree peony species are distributed in compound patterns in some distributional areas. For example, P. jishanensis and P. rockii share in the same habitat in Yan' an of Shaanxi and its surroundings; also P. rockii, P. ostii and P. qiui can be found in the same locations in the part of forest area from Baokang to Shennongjia, Hubei Province. In Luoyang, where cultivation of tree peony is more flourishing, P. rockii and P. ostii were found in the southern mountainous areas, while P. jishanensis in the north. Secondly, because tree peony cultivars are frequently exchanged, especially in the main producing areas where are usually the converging places of exquisite tree peonies from other regions. As a result, through natural and artificial hybridization, selection, the exchange and recombination of genes with difference genetic background are achieved between cultivars.

The Origin Patterns of Tree Peony Cultivars

Like other species of the world, all sorts of tree peony cultivars also are the consequence of evolvement. They are always in the evolutionary process. Both natural evolution and artificial evolution are basically determined by several common factors, which are mutation, gene recombination, isolation and selection. In the breeding of Chinese tree peony (5.1, Chapter 5), mutation and selection, hybridization (genes recombination) and selection are the main

methods of breeding at all times. The viewpoints are coincident with William's viewpoints (1984) on two origin patterns of cultivated plants. The primal and early cultivars are obtained by direct introduction and domestication of wild species, secondly by the selection of the mutated individuals (mainly bud mutation) in wild populations and cultivated groups, meanwhile, in the need of asexual propagation to reproduce. In the case of mixed-planting of several cultivars, consequently natural cross-fertilizing usually will happen. After that, as the wide application of introduction and seedling selection, the possibility of gene exchange and recombination will be further increased. The above viewpoints have been well interpreted by the book Ou Pu upon the origin of the tree peonies of Luoyang. According to the records in this book, the Luoyang tree peonies have the following origin routes:

- Direct introduction of wild tree peonies from nearby mountainous area and variation selection of plants from introduced wild species, such as ' Yupao Huang', ' Yue Shan Hong', 'Jin Xi Yao', ' Xizhuang Hong', ' Daye Shou An',' Xiaoye Shou An' etc. The famous cultivar, 'Wei Hua', came from the direct selection of wild tree peony variation living in mountain.

—Introduction from the domestic areas. For instance, in the north, there are the cultivars of Danzhou and Yanzhou such as ' Danzhou Huang', ' Danzhou Hong', ' Yangzhou Hong', ' Yu Zheng Bing' etc; in the south, ' Yueshan Honglou Zi' of Huiji; in the east,' Qingzhou Hong' (' Ting Hong') of Qingzhou. Furthermore, the Luoyang tree peonies possibly were introduced from Fenzhou, Shanxi Province. In the process of formation of the Jiangnan (the south regions of the Changjiang River) tree peony cultivar-group and the Xinan (SW) tree peony cultivar-group, tree peony cultivars are frequently exchanged in several regions, too.

The Primary and Secondary Planting Centers

The cultivation and development of Chinese ornamental tree peony is closely connected with the development of politics, economy and culture. Although tree peonies have several origin centers, with the unequal development and the differences of these centers, they have been differentiated into the primary origin center and the secondary center.

The middle and lower regions reaches of Yellow River (Huang He) is the primary origin center. In these alluvial plain areas, the climate and soil are very suitable for planting and growth of tree peonies. Additionally, here are also the political, economic and cultural centers of China in the Tang and Song Dynasty. As the old capital cities of China, Chang'an and Luoyang became cultivation centers of tree peony one after the other and have flourished for several hundreds years. Other areas are the secondary centers.

2.2 The Development of Horticultural Varieties of Tree Peony in Each Dynasty

2.2.1 General

Tree peony has 1,600 years history from wild plants to ornamental planting.

According to the elementary investigation of the records in ancient literatures, Professor Yu H., Shandong Agricultural University, thought that there were 12 cultivars in the Sui Dynasty, 11 cultivars in the Tang Dynasty, 115 cultivars in the Song Dynasty, 343 cultivars in

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the Ming Dynasty, 381 cultivars in the Qing Dynasty. In recent years, on the base of investigating widely and deeply, we have much better understood the history and current status of Chinese tree peony. Through the analysis of historical literatures, Li J. J. made an all-sided supplement and recension on the research documents of Professor Yu. H. In term of the statistical analysis of Li J.J. ' s (2002), there are about 40 cultivars in the Tang and the Wudai Dynasty, 201 cultivars in the Song Dynasty, 60 cultivars in the Yuan Dynasty, 361 cultivars in the Ming Dynasty, 430 cultivars in the Qing Dynasty. After excluding the repetition of cultivars, there are totally 850 cultivars appeared in these periods. If including about 60 cultivars of Xibei (NW) and Xinan (SW) groups from the Qing Dynasty, the total number is about 900 cultivars. Actually, about 500 cultivars were remained according to the Qing Dynasty pedigree.

2.2.2 The Ancient Horticultural Cultivars

The Sui Dynasty and the Time before Sui

The Chinese characters record on tree peony cultivar is not found before and during the Sui Dynasty.

In the book of Qing Suo Gao Yi by Liu F. in the Song Dynasty, there is an anonymous article with the title of Sui Yang Di Hai Shan Ji. It said when Yang G. (AD569-618), the second king of the Sui Dynasty, built Xiyuan (west court) in the capital Luoyang, "He wrote the rescript and commanded to contribute all countrywide birds, beast, grasses and trees to the capital (Luoyang)". Here, "20 boxes of tree peonies were contributed by Yizhou (now Yixian, Hebei)". and described the names of 18 cultivars. This word has far-reaching influence in the history of flower and horticulture in China. Lately, somebody suspected the truth of Sui Yang Di Hai Shan Ji and thought that this article was a pseudograph in the Song Dynasty, thus it is not true that Yang G.planted tree peonies in Xiyuan (Guo.S.N, 1998,1997). Because the record on the tree peony cultivars is not found in the Tang Dynasty, therefore, the facticity of the cultivar names of the Sui Dynasty appearing in the books of the Song Dynasty deserves to investigate further. However, it seems unreasonable to completely exclude the possibility of tree peony planting in the Sui Dynasty.

The Tree Peony Cultivars in the Tang Dynasty and the Wudai Dynasty

In the history of Chinese tree peony planting, the first developing climax occurred in the Tang Dynasty. During that time, enjoying tree peony was such a fashionable thing in Chang' an, the capital of the Tang Dynasty, that all of people in the whole country loved it.

Although the poems eulogizing tree peony reflected the historical facts of its planting and introduction in many areas, unfortunately, all of them did not mention names of the cultivars. From the records in the poetry and literary quotations of the Tang Dynasty and Wudai Dynasty and the literature records of the Song Dynasty, it can still suggest that:

—In the Tang Dynasty, the flowers already varied in color, such as pink, red (light red, fleshy red, and blackish red), purple (deep purple), yellow, white (whole-white and white- yellow) etc. Some cultivars have petals with blotches (namely "Tan Xin").

—Tree peonies had been introduced from many areas in the Tang Dynasty. For example, Wu Zetian., the sixth king of the Tang Dynasty, ordered people to transplant tree peony from Xihe, Shanxi (the preface of mm Dan Fu). In the end of Kai Yuan

period (AD713-741) in the Tang Dynasty, Pei S.Y. was commanded to Hebei Province secretly, he obtained a white-flowered tree peony from a joss house named Zhongxiangsi in Fenzhou, then planted it in the private garden in Chang'an. Another example is that "In the middle of Zhi De period in the Tang Dynasty, Ma P.S. acted as the governor of Taiyuan in Shanxi, he got a tree peony with red and purple flowers and transplanted it to the city downtown" (Duan C.S., You Yang Za Zu). In addition, "The flower replanted from Yuezhong", as a subtitle, appeared in the poem Shang Shu Zuo Shang Fu Mu Dan Hua written by Xu Y., a poet in the Tang Dynasty.

—In the Tang Dynasty, many variations and a few double cultivars already appeared in the tree peonies. For example, "Li Z., the third king of the Tang Dynasty, feted ministers, viewed tree peony with double petals, then intoned a poem" (Yi Ren Lu). "Li H, the 14^th king of the Tang Dynasty, ordered to plant double flowered tree peonies in front of the imperial palace, the fragrance of tree peony is so attractive when the flower began to blossom." (Du Yang Za Bian, by Su E).

—The books in the Song Dynasty recorded that several cultivars derived from the Tang and Wudai Dynasties, for example, ' Yi Nian Hong',' Wei Hua',' Ye Di Zi', and ' Qian Xi Fei' etc. (Shi Wu Ji Yuan by Gao C.; Wen Jian Qian Lu by Shao B.W.; Luo Yang Mu Dan Ji by Ouyang X.; the Song Dynasty). According to the book Qing Yi Lu by Tao G. in the Song Dynasty, "Lin Fang Dian" of the imperial palaces was built in Luoyang by Li C.X. (AD923-925), the king of Houtang period. There were more thousand plants of tree peony. The famous cultivars as follows: ' Bai Ye Xian Ren', light red; ' Yue Gong Hua', white; 'Xiao Huang Jiao', deep yellow; 'XueFu Ren', white; 'FenNu Xiang', white; ' Peng Lai Xiang Gong', purple; ' Luan Xin Huang', 'YuYiHong', 'ZiLongBei', 'SanYunZi', ' Pan ZiSu', light red; ' Tian Wang Zi', ' Chu Yang Huang', ' Huo Yan Nu', royal red; ' Tai Ping Lou Ge', yellow, double flowered.

From the mentioned above, in the Tang and Wudai Dynasties, the known names of tree peonies are approximately 20. During the prosperous Tang Dynasty, based on the differences of flower color, producing area, variation and flower form, it is estimated that the number of cultivars without names is at least 20. Thus, there should be over 40 cultivars in the Tang and Wudai Dynasties.

The Tree Peony Cultivars in the Song Dynasty

In the Song Dynasty, especially the Bei Song period, the second climax appeared in the history of development of Chinese tree peonies. The books were found, which specifically described tree peony cultivars, planting skills and the habits and mores relating to culture of tree peony. Totally there were more 10 sorts of books. Luo Yang Mu Dan Ji (1034), by Ouyang X. , made the biggest influence toward the aftertime; the second famous books are Luo Yang Mu Dan Ji (1082) by Zhou S.H. and Tian Peng Mu Dan Pu (1178) by Lu.Y. Mainly based on the above three books, at the same time, combined the related records in Luo Yang Hua Mu Ji by S.H. Zhou and Qing Li Hua Pin by Li S. and so on, the primary investigation on tree peony cultivars in the Song Dynasty is made. According to the statistic data, there are 224 cultivars of tree peony in the Song Dynasty. In which, the characters of 132 cultivars (Table 3-1) were recorded in detail, 66 cultivars were recorded very simply but the color of 52 cultivars of which could be identified.

From the records in the books, tree peony planting and

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development of cultivars in the Song Dynasty have the following features:

—Three major cultivar-groups including Zhongyuan, Xinan, and Jiangnan were rudimentarily established with the extension of the planting ranges of tree peony.

—Comparing with the Tang Dynasty, there are much more variations of cultivars in the Song Dynasty, colors and forms of flower evidently increased, too. Consequently the basic pattern of development and evolvement was established in tree peony culti-var-group of Zhongyuan.

—As the reliques of the Tang Dynasty, planting flower, enjoying flower and eulogizing flower by intoning poem remained, besides, studying flowers became an important feature in this period. A lot of books had described the origin of cultivars, names, horticultural classification, reproduction (particularly graft) as well as planting management etc. Thus a rather compete system of horticulture in tree peony has been established. They kept back rather precious treasure in the development history of Chinese Botany, Horticulture, which then stood for the international level of Chinese flower horticulture.

The Tree Peony Cultivars in the Yuan Dynasty

In the Yuan Dynasty, the planting of tree peony and other flowers were all at low tide, and tree peonies were rarely found in the articles and books. Only in Xu Mu Dan, Yao S. wrote that he met tree peonies six times in central plains of China during a period of 29 years since 1260. Although the development of tree peony was in a seemingly stagnant situation in the Yuan Dynasty, many tree peonies were still seen in the royal palaces. From the records in the books of the Ming and Qing Dynasties, it suggested that some cultivars of tree peony in the Song Dynasty had still remained. By contrast and analysis of records, a total of about 60 cultivars were identified, but only 'Heng Shan Zi' was a new cultivar in the Yuan Dynasty. Therefore, it is concluded that these cultivars were also reserved to the Yuan Dynasty in various ways.

The Tree Peony Cultivars in the Ming Dynasty

The tree peonies of the Ming Dynasty were prosperous in Bozhou, Anhui province. In Mu Dan Shi (the following called "Xue Pu"), Xue F.X. recorded 270 cultivars of Bozhou. After that, in Zun Sheng Ba Jian written by Gao L., there was an anthography of tree peonies, which briefly described tree peony cultivars of the ancient Bozhou. Later, the book of Qun Fang Pu written by Wang X.J., he also simply described tree peony and its cultivars. In terms of the records on tree peony in three books above, there are totally about 361 cultivars in the Ming Dynasty, thereinto 347 cultivars with characteristic description, 14 cultivars without characteristic description.

The Tree Peony Cultivars in the Qing Dynasty

The tree peony in Caozhou (Heze, Shandong) was the most prosperous in the Qing Dynasty, at the same time, also tree peony was thriving in other countrywide areas such as the Yangtze Delta (including Shanghai, SE Jiangsu and North Zhejiang), Gansu and so on. It indicated that there were totally 430 cultivars of the Qing Dynasty recorded in these books. On the other hand, according to Lin Xia Mu Dan (Li J.J. 1989), in Lintao, Linxia, Longxi and Lanzhou of Gansu Province, the traditional cultivars inherited

from the Qing Dynasty were at least over 50, if remained traditional cultivars of more than 10 in SW of China included, the countrywide tree peony cultivars should be about 500 in the Qing Dynasty (Li J.J. 2002).

During the prosperous period of over one hundred years of Kangxi-Qianlong in the Qing Dynasty, The tree peonies gradually sprang up all over the country. Since the Ming and Qing Dynasties, the development of Chinese tree peony has the following traits: © A continued increase of cultivar in quantity, a rapid and continuous occurrence of new cultivars, and a much richer diversity in germplasm. With the popularization and prosperity of Xibei tree peonies in Gansu, a basic pattern consisted of four major cultivar-groups of Chinese tree peony has been established. © The technology of reproduction and planting gradually tended to be perfect, and it made possible flower forcing in South of China (Guangzhou). ® After being ferried eastward to Japan, Chinese tree peonies also were introduced westward to the Occident. Thus, a foundation, which accelerated the development of Chinese tree peony and made it become an international famous flower, had been established.

2.2.3 The Current Horticultural Cultivars

The up-to-date horticultural cultivars include two parts. One is the traditional cultivars, which are mainly from the past dynasties before 1949; the other is the new cultivars produced in the past years after 1949 (including the cultivars introduced from overseas). According to the investigation in 1992-1996, the countrywide cultivars of tree peonies are about 800. With the continued increase of the new cultivars in recent years, it is estimated that there are totally over 1000 cultivars throughout China.

2.3 The Study and Use of Cultivar Resources

2.3.1 Investigation and Examination of Cultivar Resources

The General Information of Cultivar Resources

As one of traditional famous flowers, tree peony has a centuries-old history in cultivation and possesses abundant cultivars. According to statistic data, there are about 900 cultivars in ancient China (2.2, Chapter 2). According to the investigation and analysis of Professor H. Yu, there were 462 cultivars of tree peonies (Xibei and Jiangnan cultivars excluded) until 1985, including 166 traditional and 296 new cultivars.

Compared to the records of cultivars in the Qing Dynasty (Table 2-1), it suggests that, in the period after 1949, the total of cultivars have increased but some of the rare and precious germplasms disappeared. On one hand, the number of the rare cultivars decreased, including yellow, white, green-flowered cultivars; on the other hand, some special cultivars are not found such as twinborn flowered cultivars (double heads, i.e. ' Shuang Tou Hong', ' Shuang Tou Zi', ' He Huan Jiao', and double-colors cultivars (i.e. ' Er Se Hong', 'HuiMian Jiao').

According to Lin Xia Mu Dan (Li J.J. 1989) and Tong Ling Mu Dan (Liu J.F. 1992), Yu H. (1992) considered there were 542 cultivars of tree peonies in China during that time, but Xibei and Jiangnan cultivars were not included because they weren' t covered in the investigations before 1985. Thereafter the Peony Association of China (PAC) organized a reinvestigation of tree peony in 1996,

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Table 2-1 Comparison of cultivars between the Qing Dynasty and since 1949 (Yu Heng 1985)

'The data didn 't include the cultivars of Xibei and Jiangnan group.

about 800 cultivars were confirmed. In 2001, there were 94 new cultivars from Heze and Luoyang to be confirmed by the Chinese Peony Cultivars Register Committee (CPCRC). During this period, other new cultivars were also bred successively in the regions of NW and South of the Yangtse Rive in China. In terms of a countrywide investigation result made by Li J.J. et al. (1999-2003), currently there are more than 1,000 cultivars of tree peony in China.

Apparently, it is a very significant work, which was done by H. Yu, about the investigation and disposal of cultivars of Chinese tree peony. In order to avoid the disordered status, the identification and revision of tree peony cultivars was considered as the most important thing by the American Peony Society (APS) when established in 1904. This is a good experience we should use for reference. From many years experience, it will be hard to go on the revision of tree peony cultivar list without the canonical gardens of cultivar resources and the protection of new laws and regulations.

Confirmation of Major Planting Cultivar-groups

In 1989, Li J.J. divided the tree peony cultivars in North China into two groups, later he pointed out that there were three major cultivar-groups as well as several small groups in China, at the 1992 annual conference of PAC in Tongling. Then, he further ascertained that Chinese tree peony cultivars consisted of four major groups and two subgroups, thereby he had a brand-new cognition about the cultivar resources of Chinese tree peony. The later studies discussed and disclosed the origin relationships of these cultivar-groups. Here, it is necessary to mention that how to understand and deal with Paeonia suffruticosa Andr., the Latin scientific name of tree peony. It was about 200 years ago, namely in 1787, Chinese tree peony was introduced to England from Guangzhou, China by a doctor named Alexander Duncan who was working for an East Indian Company. Thereinto a double purple-flowered tree peony was transplanted to the Kew Gardens in 1789 and this cultivar was recorded and named by H.C. Andrews as Paeonia suffruticosa. It is the first woody peony plant described and named scientifically among the genus Paeonia (Li J.J. 1992). In fact, P. suffruticosa Andr., based on the record of a cultivar, is just a general appellative of Chinese planting tree peony (Zhongyuan cultivar-group), it is a cultivated complex with a complicated origin and constitution. It is a quite common phenomenon in ornamental plants such as Dendranthema x grandiflorum, Canna x generalis etc. They are all complexes with a very complicated constitution of origin and named in terms of a cultivated hybrid. Therefore, P. suffruticosa is the earliest, efficient scientific name of tree peony cultivated complex (Chen J.Y. 2001).

Literature Investigation in the Evolution of Traditional Cultivars

Among Chinese tree peonies, the excellent and traditional cultivars are paid much more attention. Recently, based on the

investigation of evolution of these cultivars, Tang Z.H. (1999,1997) concluded that:

—' Yao Huang' in the Song Dynasty possibly became extinct in the middle Ming Dynasty and it was not found in Xue Pu in the Ming Dynasty. According to Bei Shu Boo Weng Lu written by Gao S.Q. in the early Qing Dynasty, "Nowadays 'Yao Huang' already disappeared". However, it was recorded in Yu Pu with a local name of ' Luo Ying Huang'. It is possibly because people replaced the already extinct' Yao Huang' with a new cultivar of ' Luo Ying Huang'.

— 'Wei Hua' in the Song Dynasty is pinkish red, which came from the garden of Wei R.P., a prime minister of the Wudai Houzhou Dynasty. In Xue Pu, it is called 'Wei Hong' with "pinkish red petals, spiky ovary, deep and light plum-red alternately; the price higher than a city". After the Ming dynasty, 'Wei Hua' vanished. Not ' Wei Hua' but ' Wei Zi' was recorded in Yu Pu, in this book it is definitely described that ' Wei Zi' was not ' Wei Hua' of the Song Dynasty.

—The book Lu Pu of the Song Dynasty recorded ' Ou Bi' which was produced in the middle of Sichuan Province. Later in the Ming Dynasty,' Ou Bi' was also mentioned in Xue Pu. In this book, it was respectively called 'Fo Tou Qing' in Bozhou, Anhui, 'Lu Hudie' in Hebei and 'ELii Hua' by Xue' s father. Somebody considered that the current ' Dou L ii ' possibly is a synonym of ancient ' Ou Bi', but it is not that case. Xue Pu showed "' Dou Lti ' came from Deng family, hundred petals, crown flower form, it is really rare" Yu Pu also said 'Dou L li ' was "from Deng family in Bozhou, many tree peonies of Caozhou were transplanted to Bozhou". Yu Pu did not record ' Ou Bi' but described that " ' Yuguo Tianqing', pale blue and flowered later, possibly a replacement of 'Ou Bi'", It suggested that Yu P.N. already knew that ' Ou Bi' became extinct and people already replaced it with 'Yuguo Tianqing', 'Dou L li ' originated from Bozhou in the Ming Dynasty, and it was independent of ' Ou Bi'.

—The cultivar with bicolor in one flower (the ancients called it "Zhuan Zhi Hua") already appeared in the Tang Dynasty. In the late Tang Dynasty, Wu R. intoned a poem to tree peony with red-white bicolor flowers: "Gorgeous damask was divided into two parts by a rosy cloud, one half is blackish-red and the other is half of bright-red". In the Song Dynasty, Ou Pu described a cultivar of ' Qian Xi Fei' blooming in red and purple per flower; Zhou Pu recorded ' Er Se Hong' with bicolor flower in deep red and light red. In the Ming Dynasty, 'Zhuan Zhi Hong', with bicolor flower in red and white, was recorded in Xue Pu. The present 'Er Qiao' is a cultivar which flowers in two colors, purplish-red and pinkish-red, but the cultivar, with bicolor flower in red and white, is already extinct.

-'Zi Xiuqiu' was already recorded in Zhou Pu in the Song Dynasty; it was honored as "King of Tianpeng (Pengzhou, Sichuan) tree peonies". Now 'Zi Xiuqiu' of Pengzhou is still considered the best cultivar of purple-flowered tree peonies, but it

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Figure 2-3 (left)Tree peony of the Han Dynasty in Baixiang, Hebei Province

Figure 2-4 (right)Tree peony of the Ming Dynasty in Shizishan, Wuding, Yunnan Province

is the homonym of 'Zi Xiuqiu' in Luoyang, Heze and Lanzhou. — Besides 'Zi Xiuqiu' in Pengzhou, Sichuan, there are other traditional cultivars such as 'Zheng He Chun', 'LiuShiGe', 'Jin Yao Lou', ' Yan Zhi Lou' and so on identical to record of Lu Pu in the Song Dynasty. However, 'Pengzhou Zi' is not found in any books of the Song Dynasty, so it should be produced after those books of Lu Y. and Hu Y.Z. etc.

The Resources of the Old Tree Peonies

According to the investigations since the 1980' s, a number of tree peonies with more than 100 years of age still are living in China from north to south , and they are found in Hebei, Henan, Shanxi, Inner Mongolia, Gansu, Ningxia, Anhui, Jiangsu, Zhejiang, Shanghai, Guangdong, Sichuan and Yunnan (Li J.J. 2002).

In these, it is said that the oldest tree peony is the Han Dynasty' s in the Mituo Temple, Beihao village, Baixiang County, Hebei Province (Fig.2-3). The tree poeny, which is awarded by Kangxi, an emperor of the Qing Dynasty, is 380 years old up to now, and is the most north distribution in China, which is located at Chang Gao village, Bu-Ri-Ga-Su-Tai, Ningcheng County, Chifeng City, Inner Mongolia. The ancient tree peony distributed in the most south is the ' Gu Mu Dan' in Gu-Jia-Chong village, Baishi section, Lechang County, Guangdong Province, which was transplanted from Luoyang in the Qianlong period of the Qing Dynasty. The tree peonies with taller stems and luxuriant flowers are the old tree peonies growing in Lanzhou, Lintao and Linxia in Gansu Province. The old tree peony ' Shi Zi Huang Guan' of Shizishan Park, Wuding, Yunnan was planted in the Ming Dynasty(Fig.2- 4). It is a marvelous spectacle that the diameter of its flower was up to 28 cm during flowering in 1998. It is said that the ' Ku Zhi Mu Dan' (deadwood Moutan), which was found in Yancheng City of Jiangsu Province, is about 700 years old. The two cultivars with simple flowers inherited from it remain so far and they are important parent plants to breed new cultivars with heat- and humidity-resistant characters.

The old tree peonies have significant values in science, cultural-relic and horticulture. As a very important germplasm resource, the high adaptability to various environments should be highly regarded. According to "The Management Regulations of Chinese City Greenbelf, all old trees over 100 years old should be protected and put in the protection list. For example, Shanghai has registered, labeled and made a list of all the old trees in order to protect them effectively. It should be used for

reference for other regions.

2.3.2 The Research and Use of the Autumn-Flowered Tree Peonies

For the resources of tree peony cultivars, it needs to be attached importance to the collection, study and utilization of twice-flowering cultivars. The phenomenon of twice or more flowering is commonly seen in many horticultural plants. Through making use of the habit of twice-flowering of some cultivars and many years of breeding, Japanese horticulturists have produced "Kan Botan" (cold-resistant tree peony). It is a series of new cultivars which can bloom stably in the fall and winter. There are about 30 cultivars of "Kan Botan" in Japan so far. These cultivars were produced by selection of many times from the hybrid offspring of tree peony cultivars which can easily twice flower in one year. According to the ancient literatures and the related poems, since the Tang Dynasty, it was found that tree peony flowered in the autumn or the beginning of winter (Li J.J. et al. 2002; Yang Q.C. and Zhao Y.M. et al, 1992). Lately, some twice-flowering cultivars such as ' Cangzhi Hong' (Fig.2-5), 'Bingzhao Lanyu' etc. also have been found in Heze, Luoyang, Yancheng and other places and often flower in autumn. Here the Yancheng cultivars are already described in this book.

"Autumnal flower" and "autumnal burgeon" are different concepts. The autumn-flowering tree peony should be the cultivars with habit of twice flowering. It blooms twice in spring and autumn respectively. The flowers develop normally in autumn and the florescence is from the middle and late October to the middle November. Of course, the autumn-flowering tree peony also includes the cultivars which bloom in spring and autumn but the character of autumn flowering can not remain stable or the cultivars in which the terminal buds only develop and bloom in some autumns. In addition, there are some spring flower cultivars whose tip buds often sprouts and only forms leaf but usually can not bloom in autumn. It should be taken as the phenomenon of "autumn burgeon". In general, autumn burgeon refers to a phenomenon that tree peony plants sprout in autumn under abnormal conditions. It may be usually caused by the following situations:

1. Serious diseases, damage of insect and pests and poor management result in defoliation.

2. After transplanting in autumn, air temperature and ground temperature are still quite high. Once moisture is not under good control, autumn burgeon appears. Autumn burgeon happens frequently during transplanting of Zhongyuan tree peo-

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Figure 2-5 'Cangzhi Hong ', a twice-flowering cultivar

nies to the south of China. Therefore, in order to ensure blooming in next spring, the abnormal autumn burgeon should be avoided.

Chinese autumn-flowering tree peony and Japanese winter-flowering tree peony have very similar rules of development (Chen X.L., 2000). They share the following traits: early flower bud differentiation of the annual tip (axillary) bud and the second bud from the top, rapid morphological differentiation, few petals, low development level of leaf, centralized florescence usually from the middle of October to the middle of November (to the late December in Yancheng), Single or Lotus Flower Form, long florescence but flower colors no more vivid than those in spring. However, Japanese winter-flowering tree peonies bloom quite stably and the florescence is long even may last to the next January because of a higher local temperature in the beginning of winter. Formerly, there were gardens of the winter-flowering tree peony throughout Japan, but lately "Kan Botan" planting has been decreased with the popularization of forcing culture technique of tree peony (Liu Z.A., personal communication, 2003).

The resources of Chinese autumn flowering tree peony are presented mainly in Zhongyuan cultivar-group, followed by Jiangnan cultivar-group. But in the fall of 2003, the author found that some Xibei cultivars introduced in Shanghai Botanical Gardens also had the phenomenon of twice flowering. Therefore, to collect and conserve the resource of autumn-flowering tree peony is the base for breeding the new stably twice-flowering cultivars. Since there is a close relationship between twice-blooming and warm temperature, the selective breeding of such cultivars should be mainly applicable to the Jiangnan areas (the south of China).

2.3.3 The Introduction and Utilization of Excellent Overseas Cultivars

In the world, besides Chinese tree peony, there are other three series of cultivars including Japanese tree peony, European tree peony and American tree peony. They all originated from Chinese tree peony (including cultivars and wild species), but they have brightly individual characters. Therefore, the introduction, study and utilization of the excellent cultivars of them are very important for enriching Chinese tree peony resources and investigating the genetic rule and relationship of tree peonies.

Overseas tree peony cultivars were already introduced to Shanghai, Nanjing and some other places in the period of Republic of China. At the beginning of the!980's , overseas cultivars introduction were highly regarded and restarted, then it has become quite large scale and achieved good effects in tree peony production. Among the cultivars introduced from overseas, the following special and valuable cultivars should be paid attention (Fig.2-6,2-7,2-8):

Multi-color Type

The representative cultivars are Japanese 'Shima Nishiki' and French ' Souvenir de Maxime Cornu', ' Shima Nishiki' was discovered and cultivated by a flower planter in Shimane, Japan who found it from the variations of 'Taiyoh'. It is regarded as the most attractive cultivar of multi-color tree peony. The flower of' Shima Nishiki' is very beautiful and peculiar in Chrysanthemum or Rose Form with alternate color strips in fiery-red and white petals. ' Souvenir de Maxime Cornu' was bred and cultivated in France and, P. lutea and Chinese Zhongyuan tree peony cultivar were used as its parent plants. The flower is Rose-Proliferate Form with petals of yellow inside and purplish-red in brim. Florescence is late.

Black Type

Japanese ' Kokkoh no Tsukasa' is a representative cultivar. It is very precious because of numerous petals and its color darker than ' Hei Hua Kui' of Zhongyuan tree peony.

Red Type

The representative cultivars are ' Hohki', ' Hyuhga', ' Kaoh' etc. The flowers of these tree peonies are big and pure red even fresher than 'HuolianJindan' and 'NihongHuancai' of Zhongyuan tree peony.

White Type

The representative cultivars are ' Renkaku', ' Godaishuh' etc., which have big flowers in pure color as well as long and erect scape. They are regarded as the best white cultivars.

Yellow Type

The representative cultivars are American ' High Noon' and French ' Alice Harding' and ' Souvenir de Maxime Cornu'. They were the hybrids of P. lutea and Japanese cultivars (or Chinese Zhongyuan cultivars). These cultivars have pure yellow flowers, a long and late florescence. Among them, ' High Noon' normally blooms more than twice. Of course, in the hybrids of P. lutea (P. delavayi) and Japanese (Chinese) cultivars, there are still other good cultivars quite popular in the Occident market or awarded a prize by the Royal Horticultural Society. Such as ' Argosy' with the flower 17.5 cm cross, petals primrose-like yellow and the base enchased by some strips of magenta blotches; it was commended by Knight F.C.

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Figure 2-6 Japanese cultivars 'Shima Nishiki', 'Hyuhga ', 'Kaoh ', (first line from left to right) 'Hohki ', 'Renkaku ', 'Godaishuh ',(second line) 'Kokuryuh Nishiki', 'Rin Poh ', 'Hatsu Garasu '(third line)

Stern to be an excellent cultivar of the Saunders hybrids, as well as the best one in Single Form, yellow-flowered tree peonies. ' Argosy' was awarded the first prize in 1956. ' Anne Rosse' is a new hybrid of P. delavayi and P. ludlowii, and it is an optimal plant selected from the hybrid offspring. The flower is more reddish and bigger than that of P. delavayi. This cultivar was bred by Earl Rosse and gained the Distinct Award in 1961 (Bean, 1976).

The several ways of utilizing the introduced overseas cultivars are: © Direct application as ornamental plants, @ Direct application in production, ® Application in crossbreeding. At present, nearly most of introduced cultivars are later than Zhongyuan tree peony in florescence. Especially the hybrid offspring ofP.lutea and P. delavayi, it blooms much later in Mangshan, Luoyang, the florescence can extend to the middle of May, the flowering period of the herbaceous peony. It will be very useful for extension of the viewing period. But it is worth noting that there is a trend of tending to be the same florescence between some of introduced cultivars and the local ones as the time goes.

2.3.4 The Construction of Cultivars Resource Garden

It is necessary to construct several resource gardens of tree peony cultivars under a strict scientific plan and requirement in order to better protect and conserve the present excellent cultivars and accelerate scientific research to lay a foundation for cultivar register and further breeding in the future. These gardens should be established in all major production areas. The gardens will be constructed for Zhongyuan cultivar-group in Heze, Luoyang; Xibei group in Lanzhou; Xinan group

in Pengzhou and Jiangnan group in Shanghai, respectively.

It is worth emphasizing the following points when establish ar« integrative resource garden of tree peony:

Character and Mission

The cultivars resource garden is a very important base of collection, disposal, ex-situ conservation, observation and study of tree peony cultivars. The missions of a cultivars garden should include:

—Collection, introduce and conservation of abundant gene resource all over the world;

—Observation and investigation of biological characteristics;

—Provision of an important reference and consultation for new cultivar registration;

—Selection and breeding of new cultivars;

—Support of scientific popularization activity;

—Service for communication activities in domestic or overseas; -Development of tour and sightseeing activities under a

precondition of security and normal work.

Programming Principle

The requirements for programming of cultivars resource garden are:

—Determine the collection range and quantity of cultivars, the suitable size of garden, and leave enough space for future expansion according to the local natural conditions and the results of cultivars investigation;

—Cultivars garden should possess the features of easy

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Figure 2-7 French cultivars 'Alice Harding '(left), 'Souvenir de Maxime Cornu '(right)

Figure 2-8 American cultivars 'Renown '(left up), 'High Noon '(left down), 'Black Douglas ' (right up), 'China Dragon '(right down)

access, fine microclimate, fertile soil, good system of irrigation and drainage and flat landform but with a little fluctuation;

—The garden should be divided into different functional zones including the collection and show zone, the breeding zone, and the management zone (involving office and laboratory) by the paved roads combining the system of irrigation and drainage. A protective isolated boundary is needed to surround the garden;

—Create different micro-ecological environments to meet the needs of different ecotype cultivars;

—Keep a suitable distance from the surrounding environment.

Design and Construction

Planting Design On the base of garden programming, we should make a good planting design in the show zone. All cultivars may be arranged by the following two modes. One is based on cultivar evolutionary relationships. It means that different Series, Section, and Form should be planted in different zone according to the classification system of Chinese tree peony cultivars and, the same cultivar-group should be separately planted first by Flower Forms, then by colors. The other is based on the applied classification. For instance, the cultivars may be separately planted either by early flower, middle flower and late flower cultivars, or by forcing culture, cut-flower and gardening cultivars. Arrangement according to the classification system is a main content in design. Five plants, at least three but no more than ten, are required for each cultivar.

Soil Improvement A good system of irrigation and drainage and balanced fertile soil are needed for all kinds of tree peony cultivars to grow and develop well in the same soil condition. The sticky or poor soil should be improved before planting.

Cultivar Identification and Transplant Before planting in resource garden, all of the cultivars must be seriously identified, classified and labeled. The tree' s age and reproduction method of all cultivars should be as same as possible. The redundant plants must be planted in other places for the supply and replacement.

Mapping and Recording After planting, we should make a planting map, set up a permanent label and establish a resource file for all cultivars.

Management

Strengthen Cultivation Management It is needed to make a work calendar for cultivars garden in the light of planting experiences of other producing area. Meanwhile all kinds of measures should be consistent. If a plant is dead, we should replant it, analyze the reason and make a record in time.

Strict Management Regulation File management system should be strictly implemented. Cultivars garden must be taken care by some staffs. Regular record and long-term preservation of data are required, too. An especial attention should be paid to the abnormal situation (such as aridity or waterlog, very high or very low temperature, the influence of early or late frost and so on). Computer management information system should be introduced if possible in order to improve efficiency and safety.

Other Information

Under the precondition of effective protection and conservation of cultivars resource of tree peony in resource garden, it is necessary to combine the developments of scientific research, production, tour and culture in order to obtain the prominent benefits in society, economy and environment.

Because of the situation of the increasing new cultivars, an exhibition area of new cultivars should be constructed. Such new cultivars should have been recognized by the Chinese Peony Cultivars Register Committee (CPCRC). At the same time, the decaying and worthless cultivars should be eliminated in time.

next: 3. The Evolution of Cultivars