FINAL TECHNICAL REPORT OF PAULOWNIA PROJECT
(PHASE II) (3-P-86-164) Xiong Yao Guo ASSOCIATE PROFESSOR CO-LEADER OF PAULOWNIA PROJECT FINAL TECHNICAL REPORT OF PAULOWNIA PROJECT PHASE II (APRIL 1987-DECEMBER 1990) SUBMITTED TO INTERNATIONAL DEVELOPMENT RESEARCH CENTRA (IDRC), CANADA BY PAULOWNIA PROJECT THE CHINESE ACADEMY OF FORESTRY BEIJING, CHINA JULY 1990

The program was undertook by paulownia project staff from Forestry Research Institution of Chinese Academy of Forestry (CAF) in the assistance of 10 experimental stations located in 6 different climate zones. Some of scientists and graduate students from other Research Institution of CAF, Genetic Research Institute of Chinese Academy of Science, Nanjing Meteorology University also temporarily part time joined this programs. Total about 32 persons were directly involved in research activities of this program.

In order to guarantee the program smoothly going on, State Scientific and Technology Council (SSTC) and Ministry of Chinese Forestry (MCF) listed it as key program and meanwhile provided financial and administrative supports to the project. Local government also offered manpower and funds for each of research stations.

Ever since the program started, a lot of senior staffs and scientists from IDRC general office and branches office in Singapore always timely offered us useful, efficient and critical help, service and technical guidance. Specially Dr. Cherla B. Sastry did marvelous efforts and played critical role in the project. Dr. C. and Dr. G. Guyot served excellent guidance in paulownia tree improvement and intercropping.

Prof. Zhu Zhao Hua

Deputy Director

Forestry Research Institute

SUMMARY In order to increase the production, quality of paulownia, the comprehensive benefits of its intercropping and explore the utilization of paulownia the follow studies were conducted in paulownia project Phase II (March, 1987 - March 1990) by paulownia project under the support of IDRC.

1. Tree improvement aimed at breeding out fast growing, high resistance and high wood quality paulownia.

2. The comprehensive study on paulownia-crop intercropping so as to determine the optimum intercropping patterns.

3. Searching possible methods for comprehensive utilization of paulownia's wood and leaves.

4. Economic analysis on paulownia intercropping and utilization.

The results were summarized as follows:

Tree improvement

During Phase I, 881 plus trees were selected, 120 crossing combinations of 16 plus trees of control pollination were completed. 95 ha clonal testing plantation and gene pool were established, and 4 plus clones, PH01 (Paulownia hybrid No. 1), PS01 (Paulownia fortunei selected No. 1), C001 (Paulownia fortunei plus tree No. 1) and C161 (Paulownia tomentosa) were selected. All studies in Phase II were further continuously conducted based on the researches and achievements of Phase I.

During Phase II, nursery stage test and selection of paulownia plus clones, progenies of control pollination of Phase I were carried out. 24 ha clonal and 20 ha progenies tree test plantation were established. Total 1200 clones were involved in this test experiment.

The difference on growth, adaptability, disease resistance, heredity parameters etc. of paulownia intra-, inter-specific provenances and clones were investigated and systematically analyzed. Wood properties, water, drought and cold tolerance of several plus clones were measured. Two plus clones C020 (P. fortunei) and C125 (P. elongata) were selected based on above series of tests. These two plus clones were evaluated by scientists and experts of Sichuan and Shandong Province, respectively. Ministry of Forestry will further evaluate and identify these two clones in the end of 1990. So to speak, total 6 plus paulownia clones have been selected since the support of IDRC from 1983. Based on the extension during Phase I, 60 million root cuttings of plus clones were provided to farmers and 110 ha demonstrative plus clonal plantation were established during Phase II.

Paulownia-crop intercropping

Research sites and materials were 25 ha paulownia-crop intercropping plantation and various agroforestry models established during Phase I. Intercropped crops were mainly wheat, corn and cotton. Research parameters included variation of growth, roots distribution of paulownia and crops, modification of microclimate, energy balance, water use, soil physic-chemical characteristics, material cycle, fauna and micro-organisms, the effects of paulownia on physiology, yield and quality of crops and evaluation on economical, social benefits. The optimum models of paulownia-crop intercropping were simulated.

Timber of paulownia in the determined best model were 18.6 m³ higher more than traditional model though there were no reduction in intercropped yield. Economical analysis shown that the net present value (NPV), benefit cost rate (BCR) of the optimized models were 54.6% and 33% increased than monoculture crops and 7.35% and 5% than traditional models, respectively.

As so far, the high productivity intercropping models have been extended for 40000 ha. This research have been evaluated by famous scientists in China on May 30, 1990. Experts concluded that the comprehensive research on paulownia-crop intercropping is a leading study in China and reach the advanced level in the world. The optimized intercropping models could be extended largely by farmers in the North Central China Plain.

Other Forms of Paulownia Agroforestry

Besides paulownia-crop intercropping, various paulownia based multiple story agroforestry experimental models were established. In these models, the upper layer is paulownia, second stories are shrubs, fruit trees and teas etc. Under stories are usually crops manure, vegetables, cash and medical crops. The major multiple agroforestry models are paulownia + fruit trees (apple, pear, grape, haw) + crops, paulownia + ornamental plants (magnolia, camellia and pump), paulownia + tea + legume, paulownia + bamboo, paulownia + mushroom, Auricularia auricula-judae), paulownia + medical herbs (peony, Coptis chinensis).

Results shown that the multiple stories paulownia agroforestry models have high economic benefits. Paulownia + tea and paulownia + mushroom (Auricularia auricula-juade) were awarded as advanced scientific and technology award by Sichuan and Shandong Province, respectively. These two models were welcomed by local farmers. As so far, 40 ha demonstrative plantations of former model were formed, and the later have been applied by 130 house holds and 2 million bags of mushroom have been harvested.

Economics and Utilization of Paulownia

The comprehensive research on economics of paulownia were focused on paulownia marketing and management, integrated benefits and economical evaluation of paulownia-crop intercropping, evaluation and optimization of best paulownia-crop intercropping model, economical analysis of paulownia nursery production and leaves and flowers as fodder of paulownia.

In terms of utilization, using paulownia leaves and flowers as fodder to feed pigs and chicken were succeed, but failed in feeding silk womb. At present, experiment on using paulownia leaves and flowers as fishes fodder is still going on. Results indicated that using paulownia leaves to replace 15% of composite fodder was the best description for pigs and chicken. It was evaluated by experts and scientists and awarded as advanced scientific and technology award by Shandong Province. As so far, most of house holds in Cheng Wu and Luyi counties of Shandong and Henan Province, respectively, are applying the new fodder. It was estimated that this new methods could save grain 80 million kg for two counties, and producing 1 kg meat could save 0.4 yuan cost.

Extension and Communication

All training, workshop, visit and other forms activities have great influences both in China and in the world. There were more than 100,000 domestic farmers, technicians and governors and 200 foreign experts of 40 countries visited our experimental sites.

Up to now, 6 research findings was awarded as advanced scientific and technology awards by provincial and/or Ministry of Chinese Forestry. Project leaders Prof. Zhu Zhao Hua, Lu Yin Yu and Xiong Yao Guo were awarded by the State Council of Peoples' Republic of China for their marvelous efforts to the exploration of rural area in North-Central Plain of China. Paulownia project were awarded as excellent project by the Chinese Academy of Forestry.

I INTRODUCTION Paulownia is an indigenous, very adaptable, fast growing and multi-purpose agroforestry tree species. It plays a very critical roles in providing timber, fuel wood, fodder and food to Chinese farmers, especially in the North Central Plain area. From early 1970s, a lot of scientists and researchers have been involved in paulownia research. IDRC started the financial and technical support to paulownia project of Chinese Academy of Forestry (CAF) from 1983 - 1986 as the Phase I. During Phase I, four paulownia plus clones were selected from 831 trees, 55 ha clonal test plantation were developed in six stations and 25 ha of paulownia-crop intercropping experimental site were established. Under the influences of paulownia research, a large scale of paulownia plantation were settled up in the farms and "four sides" in China. Up to date, about 2 million ha of paulownia-crop intercropping and 60,000 ha nursery have been developed.

Based on achievements of Phase I, continuously study were conducted during Phase II under the support of IDRC from March 1987 - March 1990.

The objectives were:

to breed out fast growing, high resistance and high wood quality paulownia.
to investigate the effect of paulownia on microclimate, soil characteristics, animal funa, and the physiology and finally the yield of crops in paulownia-crop intercropping fields so as to determine the optimum intercropping models.
to find out the possible methods for comprehensive utilization of paulownia's wood and leave.
to explore economic analysis methods on paulownia intercropping and utilization.

II MATERIALS AND METHODS

1. Tree improvement

1.1. Selection of plus trees and provenances

120 counties were defined as selecting county in paulownia distribution area of South, Middle and North of subtropics and temperate zone. On the base of the type classification applying the method of five big tree selection for plus tree, 20 plus trees for previously selection and 10 plus trees for final selection in each county was planted. The plus trees selected from each county regards to be a provenance for the provenance test. The seeds, roots cuttings from plus trees will be used in the nursery testing at first and then test plantation of plus trees, family and provenances after through nursery reselection.

1.2. Control pollination

Based on the elite selecting, four important species P. fortunei, P. elongata, P. tomentosa ad P. Kawakamii with much different in Phenotype will be selected. Four trees in each species will also be selected as parents for control pollination on the basis of design of diallel-crossing without selfing, 240 combinations should be completed.

1.3. Nursery testing

Nursery testing for the materials from provenance, family, clone and crossing progeny will be conducted in Yanzhou of Shangdong prov., Tongling of Anhui prov., Zhizhong of Sichuang prov., etc. The study contents including height of seedling, ground diameter, growth ryzhem, character of shape, periodic biological phenomena, insect-resistance, disease-resistance, frost-resistance and so on will be tested and measured. Randomized plot design with 3 replications, 10-15 trees for each plot, spacing for 1x1 M will be used in the test.

1.4. Testing plantation

According to the results of testing in nursery stage, single tree of fast-growing and strong resistance will be screened out for clone material to breed again and to put into clonal test forest. Randomized plot design with 3-4 replications, 3-4 trees for each plot, spacing for 6x8 M will be used. The contents of height, DBH, VOT, crow width, growth of trank, shape character, periodic biological phenomena, adaptation, disease/frost/draught resistance and so on will be measured in 10 experimental stations of Paulownia project. After half rotation the superior clones will be selected from clonal test forest and to be evaluated by experts and to be propagated rapidly for extension to the farmers.

2. Paulownia-crop intercropping.

Different spacings of paulownia-crop intercropping, namely 5 x 6, 5 x 10, 5 x 20, 5 x 40 and 5 x 50 m, were established with, 1-year-old saplings in 1983 in Dangshan. All plantation rows were oriented on a north-south direction. Randomized Complete Block Design (RCBD) with three blocks (replicates) was used each spacing treatment. For comparison, a control plot of same crops was grown in a nearby field. Most of studies such as microclimate, energy-balance, effect of paulownia on soil and crops, the biomass of paulownia and crops etc. were mainly conducted in this sites. Other experimental sites such as Minqan and Luyi, Henan province and Yanzhou and Chengwu, Shang Dong Province were also included in this study. The detail research were described in each separate report.

III RERSULTS AND DISCUSSION

Tree Improvement 24 ha paulownia clonal experiment plantation, 16.5 ha provenances and family testing forests, 20 ha gene pool have been set up in Phase II. Total area of paulownia plantation for tree breeding were 111.5 ha including 700 plus trees or clones from plus trees, 500 clones coming from hybrid progenies of control pollination. Two plus trees C020 (Paulownia fortunei) and C125 (Paulownia elongata) were selected in Phase II and the other 4 superior clones PH01 (paulownia hybrids). PS01 (clone selected from Paulownia fortunei), C001 (Paulownia fortunei) and C161 (Paulownia tomentosa) selected in Phase I were saved as test materials. Four major characters, biological characteristics, ecological adaptability, disease resistance and timber properties were tested. Up to now 32 million saplings of the selected superior clones have been extended in 17 provinces cities and autonomous regions. Research stations were chosen as subtropical zone, Tongling city in Anhui Province, temperate zone, Yanzhou County in Shang Dong Province.

Result of seedling stage of paulownia plus trees is as following:

Provenances Trail

Interspecific growth differences.

In order to meet the needs of "difference ecological conditions with suitable tree species", growth of seedlings of plus clones of Paulownia elongata, P. fortunei, P. tomentosa and P. catalpifolia the major species in paulownia genus were tested. The hight of seedlings and the hight and ground diameter of root cuttings among different species were extremely different except the ground diameter of seedings of 4 species were at significant level.

Genetic parameters of height and ground diameter.

As indicated in Table 1 that there are significant and / or extremely significant different in height and ground diameter of plus tree saplings among 4 main paulownia species. Differences can probably provide a base for clonal selection at nursery stage. As the difference of height of saplings was greater than ground diameter so that the height of saplings should he a major factor in nursery selection.

Analysis of squire difference indicated that genetic variable coefficients with height and ground diameter of roots cuttings of plus trees of Paulownia tomentosa, P. elongata, P. fortunei, P. catalpifolia and P. fargesii were 10%/9%, 15%/18%, 17%/17%, 15%/16%, 18%/15%, respectively. It shown that clones from plus trees have been very wide-ranging variable and genetic potential which can be used for nursery stage selection. The broad heritability of hight and ground diameter were 78%/68%. 87%/87%, 92%/89% and 78%/83%, which were quite high. Heredity variable coefficient of height and ground diameter of seedling of Paulownia tomentosa, P. elongata, P. fortunei and P. fargesii were 18%/4%, 4/5%, 6%/7% and 6%/12% higher than roots cuttings, respectively. This can be explained that the height and ground diameter growth of paulownia trees are controlled by genetic factors. There existed differences in heredity variable coefficient and broad heredity among paulownia species. Based on this two parameters, the selective potential of Paulownia fortunei were the highest and then P. elongata, P. catalpifolia, P. tomentosa and P. fargesii.

Difference of the inter-provenances.

During the nursery stage, testing included height, ground diameter and cold-resistant of inter-provenance, there were extreme significant differences in the height and ground diameter among paulownia inter-provenances.

As indicated in Table 2, the differences of paulownia inter-provenances were affected largely by ecological factors for 40 provenances of Paulownia. fortunei. Regression analysis shown that the growth of height and ground diameter were mainly affected by precipitation and latitude. The regression equations were:

Yn=13.0912+0.0188X1+0.0013X2+0.0 703X3
Yd=9.9040+1.3982X1-0.0036X2+0.1519X 3

Here X1, X2 and X3 were precipitation, longitude and latitude, respectively.

Table 1. LSR Test for the Height and ground diameter of Paulownia plus trees

Table 2. LSR Test for Height of 40 provinces of P. fortunei

Regression analysis were also done between cold-resistance of paulownia from difference provenances with longitude, latitude, annual mean temperature, precipitation and minimum temperature of January. Results stated that the difference of cold-resistance is negatively correlated with latitude, annual mean temperature and positively correlated with minimum temperature in January. The regression equation were presented as:

Y=17.7443-0.3400A-0.1870B+0.1865 C

Where A, B, C represent latitude, annual mean temperature, annual minimum temperature in the January, respectively.

Difference of plus trees for intra-provenance.

Height and ground diameter of seedlings and roots cuttings of Paulownia fortunei from 4 provenances have been analyzed.

Results shown that there were significant and insignificant different in height and diameters of intra-provenance, respectively. It can be concluded therefore, that it is possible to select plus trees among intra-provenance and height could be the main selective factor both for seedlings and root cuttings of intra-provenance paulownia.

Variances analysis and selection of paulownia provenances.

54 provenances of P. fortunei were analyzed by the principal component with 12 major meteorology factors, the devote rate of principal component was over 90%. The first principal component was low temperature. The second was high temperature. The third was coeffects of humidity and accumulative temperature.

Based on the "PCA" test schedule, 54 provinces were classified into 3 types as presented in two-dimensional distributive map (Fig 1). The first type is superior provenance including most parts of Hunan. Fujian and Sichuan provinces as well as some regions of Guangdong, Guangxi and Zhejing provinces.

Fig. 1. Classification of Paulownia provinces' distribution

The second type is ordinary provenance including most parts of Hubei Anhui Province and some parts of Henan, Zhejian Provinces. The third type is worse provenance including most parts of Guizhou Province and some regions of Yunnan, Sichan Province.

Control pollination

This study was carried out on the basis of plus trees selection. The involved species has typical genetic characteristics or mark genes and high possibility to obtain superior hybrid vigor according to preliminary testing such as P. fortunei, P. elongata. P. tomentosa and P. Kawakamii. 16 plus trees of 4 species from difference ecological area were selected as parent trees.

By the end of 1989, total more than 230 crossing combinations were obtained by control pollination (Fig. 2) and 160 of them have been past seedling stage testing. 180 superior hybrid clones have been screened out and 3 ha superior clones testing plantation were established in the Yanzhou, Shandong province and Xingren county, Guizhou province. At the same time, 45 hybrid families were selected and collected in 7.5 ha. family testing plantation, in Yanzhou County, Shandong Province and Tongling county, Anhui Province. As described by Dr. Szikla, a forest genetic breeder from British Colombia University of Canada, that "it would be very successful if only 50% combinations of control pollination can be completed due to it is a very difficult experiment". It is so because of parent trees are distributed over 7 provinces long distance away from one another, anthesis were only last one month and there were gaps for flowering time of each species. Every parent tree were in 15-20 m in height. It is very difficult to complete the artificial control pollination. In order to solve these problems, grafting of flower branches, storage pollination and other measures were also adopted. Based on 4 years experiments, however, the successful rate was only about 70% because of it was affected by natural calamities and heavy and light bearing years. Fortunately, a lot of information and initial results were obtained from early experiment, especially from the seedling stage testing. Fruit bearing rate of control pollination, over-parent dominance rate, general combing ability of specific combining ability of seedling stage were stated as follows:

Fig. 2. Artificial control pollination

Fruit bearing rate of artificial control pollination.

Fruit bearing rate of artificial control pollination among plus trees rate ranged from 0.5% to 74%. It explained there were not isolation appearance, both in interspecific and intra-specific, but existed quite big difference in fruit bearing rate.

Table 3 shown that the fruiting rate could be even higher if the female parent has naturally high fruiting rate such as P. tomentosa and P. kawakamii etc. For example, 31% and 27% of fruiting rate were obtained from the combinations of P. tomentosa and P. Kawakamii as female parents.

Over-parent dominance of crossing progeny.

Over-parent dominance rate (heterosis rate) is growth percentage of crossing progenies comparison with their parents. The heterosis rate of each combination for 16 plus trees and each species were calculated (Table 4).

Height and ground diameter of 10 combinations are higher than their parents. The height and ground diameter of rest 6 combinations were less than their parents among which there are 2 intraspecific combinations such as P. fortunei X P. fortunei and P. tomentosa X P. tomentosa. The hybrids from 67% of interspecific combinations and 50% of intraspecific combinations possess strong heterosis. The height heterosis rate of each combination from high to low are P. fortunei X P. tomentosa, P. kawakamii X P. elongata., P. kawakamii X P. kawakamii, P. tomentosa X P. fortunei, P. kawakmii X P. fortunei and P. fortunei X P. kawkamii. In terms of ground diameter, the heterosis rate are P. kawkamii X P. kawakamii, P. kawakamii X P. elongata, P. kawakamii X P. tomentosa, P. fortunei X P. kawakamii and P. tomentosa X P. fortunei. These combinations could be used in future productions of paulownia.

Based on progeny seedlings test, general combining ability (GCA) and specific combining ability (SCA) of each parent were calculated. GCA and SCA of 16 single plus trees of 4 paulownia species were used for crossing with P. fortunei which used as a male parents. In general, GCA of the height of P. kawakaii and P. tomentosa as female parents was higher than P. elongata and P. fortunei (Table 5). High positive value of GCA meant that the parent trees have strong heterosis is controlled by genes. GCA of ground diameter was as same as height, but varied with the different interspecific and individual trees. SCA was different in hybrids of different individual trees. For example, P. fortunei No.4 acts as male parent, the better plus trees for female parents are P. fortunei NO.1 and NO.3, P. elongata NO.3 and NO 4 and P. tomentosa NO.3. Conclusions, however, need to be further approved through plantation test.

Table 3. Fruiting rate of control pollination (%) of 4 Paulownia species

CLONES	P. FORTUNEI	P. ELONGATA	P. TOMENTOSA	P. KAWAKAII
P. fortunei	15	19	4	5
P. Elongata	37	14	31	8
P. tomentosa	74	3	27	19
P. Kawakamii	53	14	33	9

Table 4. Over-parents dormancy rate (%) of different crossing combinations

CLONES	HEIGHT		GROUND DIAMETER (CM)
	OVER PARENT	OVER PARENT	OVER PARENT	OVER PARENT
FxF	-10	-7	-4	-3
FxE	-11	7	0	-2
FxT	9	41	22	32
FxK	2	21	23	23
ExF	3	8	2	6
ExT	-16	-18	-11	-16
ExE	10	-3	21	10
ExK	-8	-19	-9	-24
TxF	14	17	25	22
TxE	3	-3	3	-3
TxT	-10	-7	-10	-12
TxK	-1	4	19	27
KxF	13	11	19	18
KxE	27	6	40	23
KxT	12	10	21	35
KxK	18	15	94	92
Average	3	5	16	14

F = P. fortunei, T = P. tomentosa. E = P. elongata and K = P. kawakamii

Selection and testing of superior clones

Since the development of paulownia in China is mainly depended on paulownia clones (root cuttings) so that the selection from plus trees and progenies of hybridization and regional testing will be the most important research fields in paulownia breeding. 55 ha paulownia clonal testing were established in 6 experimental stations during Phase II. Over 1200 clones were tested in different places. 6 Superior clones, PH01 (Fig. 3), PS01, C001, C161 (Fig. 4) were selected during Phase I and C020 (Fig. 5) and C125 (Fig. 6) have-bee screened out during Phase II. Plus TF33 was selected by Henan Agricultural University under the organization of CAF. Nursery stage ad plantation stage including growth development, environmental interaction, various genetic parameters, witches' broom disease-resistance, light penetrability, cold-resistance, drought-resistance, water- tolerant ability and timber properties were tested. The average height, breast height diameter and timber volume were increased by 26%, 26% and 70% than the local dominant species or varieties. The timber volume per tree of PH01, C025 and TF33 reached 0.56 m at 8-year-old. The trunk form was improved. Trunk form quotient were over 0.4. Mean infection rate of paulownia witches' broom disease is 16%, which is lower than control. Adversity-resistance and timber quality were also increased. The trunk of C001 and C002 are very straight and tall. The broom disease-resistance ability of C161 were considered as the best clones. All this achievement brought great hope for paulownia breeding. As so far, 3.737 million trees of 7 superiors clones have been extended into 17 provinces, cities and autonomous regions. The total economic benefit increased by 933 million Yuan RMB.

Table 5. General specific combine ability of Paulownia. fortunei as male parent

CLONES		HEIGHT					GROUND DIAMETER
		SCA				GCA		SCA				GCA
1 2		3	4		1	2		3	4
P. fortunei	1		15.9	-98.12	259.9	-79.1			4.3	-0.7	0.4	-1.5
	2	104.9		-43.13	17.9	-135.1		0.7		0.0	0.9	-0.2
	3	118.9	91.9		453.9	-239.1		0.8	6.6		3.0	-3.8
	4	-1.1	-152.1		-227.1	39.9		-2.1	2.5	-1.7		1.1
P. elongata	1	-57.4	-154.4	-284.4	284.6	72.2		-2.3	3.1	-3.2	1.1	0.9
	2	-81.4	-224.4	-306.4	178.6	146.2		-1.2	2.8	-1.9	-0.4	0.7
	3	-23.4	85.6	44.6	437.6	-179.8		0.0	7.7	1.6	4.6	-4.5
	4	105.6	90.6	-127.4	409.6	-157.8		0.5	6.6	0.7	2.9	-3.1
P. tomentosa	1	-90.4	-224.4	-202.4	194.6	109.2		-5.6	-1.7	-4.4	-2.8	5.3
	2	-4.4	-145.4	-227.4	24.6	39.2		-3.8	0.1	-4.6	-1.1	3.6
	3	17.6	-53.4	-128.4	345.6	-58.8		0.4	4.7	-0.2	1.6	-1.7
	4	-63.4	-301.4	-254.6	152.6	157.2		-0.5	4.4	-0.5	1.6	-0.8
P. kawakamii	1	-84.4	-140.4	-267.4	-259.6	79.2		-3.4	2.2	-4.1	-0.5	2.4
	2	-15.4	-134.4	-261.4	307.6	36.2		-0.4	4.0	-2.0	1.9	-0.7
	3	-92.4	291.4	-319.4	179.6	176.2		-2.4	0.2	-2.7	-2.1	2.8
	4	-110.4	-55.4	-72.4	275.6	-10.8		-4.2	4.4	-0.3	-1.2	0.9
GCA		14.5	104.5	181.5	-305.5			1.6	-3.8	1.4	-0.6

Fig. 3. Selection plus paulownia hybrid PH01, the extreme front of the 5-year-old Paulownia clonal test plantation in Yanzhou, Shandong Province

Fig. 4. The right front is witches' broom resistant plus clone C161 (Paulownia tomentosa) in 8-year-old Paulownia clone test plantation in Minquan, Henan Province.

Fig. 5. Selected plus Paulownia fortunei clone C020, the extreme right, in 5-year-old paulownia clonal test plantation in Zizhong, Sichuang Province.

Fig. 6. Plus Paulownia elongata clone C125 demonstration plantation in Heze, Shangdong Province.

The performance and characteristics of the selected 7 clones were described as follows:

Nursery stage test of plus clones

Nursery stage testing is a key link of early selection which directly related with the effects of the superior variety selection and total genetic gain per unit time. Seedling stage selection (Fig. 7) of paulownia were mainly on the growth, such as height and ground diameter factors and resistant, especially to paulownia witches' broom disease, and others. Analysis were conducted with 7 clones respectively, the genetic parameter of height and GD and LSR significant testing were calculated for each clone. 16 sister clones of the 7 superior clones have been secondary screened out on the base of the test. Direct genetic gains of superior clones were calculated (Table 6).

It could concluded from Table 6 that height and ground diameter of 7 clones were significant different. Mean heredity variable coefficient were 14% and 17%. Broad heritability is 74% and 75%. These shown that seedling stage selection is possible. Genetic gains of height and ground diameter of 16 sister clones were 14% and 10%. Mean over-parent dominant rate were 22% and 18%. Height heredity variable coefficient and over-parent dominant rate of P. fortunei clone were higher than ground diameter that is why height selection of P. fortunei has even more hybrid vigor and heredity potential. Conversely, ground diameter was better selecting factor for other species. Annual growth trend at nursery stage of 7 clones was presented in Figure 8. Annual growth cycle can be divided into 3 stages, initial stage (planting date to June 10) fast growing stage (June 11-Sept.10) and last growing stage (Sept.11-terminal). 80% of growth increment were gain during fast growing stage. There are two peaks in height and ground diameter of all clones, except C020. First peak appeared about in the middle of August and second in the middle of September. Annual growth rhythm and phenology were different among each clones.

Click to see the image(a) Click to see the image(b)

Fig. 7. Paulownia plus clone at nursery test stage (a) one month-old, (b) 8-month old at transplanting time. Table 6. Nursery test result of 7 Superior clones

CLONES			C001	C020	C125	C161	PS01	PH01	TF33
Testing places			Zizhong	Zizhong	Yanzhou	Yanzhou	Yanzhou	Yanzhou	Linyiny
Selection rate			1.5	1.0		1.0	0.4	0..5	0.3
Height	H (M)		1.61	1.76	3.71	3.38	3.67	3.93	4.18
	GCV (%)	A	19.3	22.1	7.3	13.7	16.6	5.0
	PCV (%)	B	23.2	24.5	10.9	14.5	17.5	6.2
	NW (%)	C	70	80	45	89	90	67
	GG (%)	D	20	9	4	14	29	9
	SFI (%)	E	44	16		17	13	24	16
Ground	D (CM)		3.8	4.1	5.0	5.5	5.5	6.4	5.9
diameter	GCV (%)		16.1	14.6	42.2	8.9	10.4	7.2
	PCV (%)		18.3	16.6	44.4	11.2	12.0	9.1
	NW (%)		78	78	90	64	76	62
	GG (%)		3	-9	20	12	21	11
	SFI(%)		11	-5		22	23	32	25

A=heredity variable coefficient B= C=broad heredity rate
D=heredity E=over parents dormancy rate

Fig. 8. Growth and ground diameter growth rate of 7 Paulownia plus clones at nursery stage.

Tree plantation test of plus clones.

Growth rate.

Over 1979-1980, all the selected plus clone was planted in Yanzhou, Shangdong Provinces, Fuguo, Henan Provinces and Muchuang, Sichuang Provinces and Paulownia fortunei were limited in Zizhong, Shichuang Provinces only, respectively, for comparative testing. The growth process of 7 clones for 8 years were showed in Table 7.

Volume of P. furtunei and average volume, height and ground diameter of 7 clones were 27-70% and 70% higher than control (Table 8).

Regional test.

In order to investigate the adoptability of each clone to diverse ecological conditions, different climate zones, flora, soil and sea level conditions were selected for experimental stations. Zizhong and Muchang, Sichuang Province, Tonglin and Huaibei, Anhui Province, Yanzhou, Shandong Province, Mingquan, Fugou, Nanyang, Lingbao and Yuxian, Henan Province, Yangii, Shanxi Province, Jinchuang, Ganshu Province, Guilin, Guangxi Zhuang Autonomous Region, Longmen, Guangdong Province, Xinren Guizhou Province. Each clone were distributed into at least 3 experimental stations. Results shown that there were much difference in terms of growth among each clone at same growth conditions and/or same clone at different locations (Table 9).

P. fortunei clones C001, C020 and PS01 has outstanding performance in southern stations, which could be suitable for the south part from Yanzi River. The other clones could be the candidate species for North China, Hanzhong as well as Yanzi River Valley.

Quantitative heredity.

Variance, covariance and polyphyletic variance of WILKS as well as poly-distance significant test of STUDENTITED for height and breast height diameter of 23 clones at 5-year-old were conducted for getting information on early characteristics transmit ability under different growth conditions.

F value of clone (A), site (B) and interaction item (AB, AC and ABC) reached extremely significant level, i.e. there were greater difference in height and breast height diameter among clones (Table 10). Growth of clones was more affected by environmental conditions than its genetic. Similar results were also obtained by WILKS analysis (Table 11).

Table 7. Growth process of 7 clones at different age and different places

CLONES		C001	C020	C125	C161	PH01	PS01	TF33
PLACE		Zizhong	Zizhong	Yuanzhou	Muchuan	Yanzhou	Zizhong	Fugou
1	H	1.6	1.76	3.71	3.38	3.93	3.67	4.58
	D	3.84	4.05	4.96	5.51	6.43	5.47	5.15
2	H	3.30	2.97	5.27	3.85	5.32	5.26	7.49
	D	5.90	4.30	9.00	6.10	8.50	8.80	9.18
	V	0.0117	0.0170	0.0138	0.0119	0.0121	0.0131	0.0177
3	H	6.03	5.91	8.55	4.47	7.9	6.67	10.40
	D	10.70	9.60	16.30	7.90	14.60	13.30	14.01
	V	0.0319	0.0270	0.0960	0.0153	0.0171	0.0504	0.0466
4	H	7.15	7.67	11.05	5.59	11.09	8.03	13.56
	D	12.70	12.60	24.30	11.40	19.00	15.90	19.16
	V	0.0521	0.0512	0.2243	0.0295	0.1396	0.0855	0.1010
5	H	8.17	8.81	12.62	7.26	11.45	8.32	16.66
	D	14.6	14.40	28.20	14.10	23.90	17.20	24.18
	V	0.0850	0.0836	0.3294	0.0577	0.2312	0.1106	0.1715
6	H	8.96	9.23	13.64	8.28	13.07	8.77	19.57
	D	15.90	16.00	30.9	16.10	27.30	18.62	28.92
	V	0.1325	0.0939	0.4158	0.3261	0.1361	0.1361	0.2513
7	H	9.44	10.27	14.25	8.39	13.69	8.96	22.25
	D	17.10	17.00	33.60	18.70	28.70	19.30	33.33
	V	0.1363	0.1166	0.4732	0.1118	0.3683	0.1495	0.3349
8	H	9.65	10.40		9.59	13.98	9.02	24.73
	D	17.90	17.70		19.90	29.00	20.20	37.40
	V	0.1319	0.1631		0.1408	0.4047	0.1560	0.4198
9	H	9.91	10.69				9.36	27.04
	D	18.30	18.40				20.60	41.12
	V	0.1436	0.1643				0.1744	0.5017

Table 8. Comparison of growth rate of 7 plus clones versus control

CLONES	AGE	HEIGHT (m)	DIAMETER (cm.)	VOLUME (m3)
C001	8	13.40	26.6	0.3336
C020	8	10.69	18.4	0.1643
C125	7	16.76	34.8	0.5774
C161	7	9.59	19.9	0.1408
PH01	5	11.45	24.1	0.2312
PS01	5	10.20	24.0	0.2133
TF33	8	27.04	41.1	0.5016
CONTROL	7	8.48	26.1	0.2333

Table 9. Regional test result of 7 clones

CLONES	AGES		H			D			V
		A	B	C	A	B	C	A	B	C
C001	5	13.40	9.19	9.51	26.6	17.3	16.7	0.3336	0.1098	0.1124
C020	7	8.87	7.78	10.60	19.1	16.2	24.5	0.2013	0.0914	0.2817
C125	7	16.80	11.18	11.70	34.8	24.6	24.7	0.5774	0.2557	0.2510
C161	5	9.50	8.20	9.15	21.6	16.7	18.4	0.2189	0.1029	0.1119
PS01	5	7.46	10.20	8.40	18.5	24.0	18.7	0.1025	0.2133	0.1319
PH01	5	8.87	11.50	10.70	21.0	24.1	22.1	0.1385	0.2312	0.1883
TF33	5	10.40	15.20	8.87	22.8	23.6	23.0	0.1356	0.6987	0.1927

* A, B, C presented different places

Heritability of 23 clones in the interaction cases were 10%, 5% and 53% in height in 1984, respectively, and were 59% and 51% at breast height diameter in 1983 and 1984, respectively. Heritability of height was very low at planting year. While, the heritability of height or breast height dirmeter at t