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Abstract Based on the 6yearold young forests of 40 cypress （Cupressus funebris） families from four provenances （Fengdu County， Youyang County and Zhong County of Chongqing City， and Qiandao Lake in Zhejiang Province）， differences in growth traits between families and provenances were studied to select excellent families， so as to provide necessary data support for the upgrading of cypress seed gardens and inferior thinning of seed gardens. The results showed that there were significant differences in tree height， diameter at one meter height， crown width and growth potential between families and provenances. The coefficients of variation among families were 10.25%， 7.19%， 5.91% and 0.98%， respectively， and the coefficients of variation in tree height and diameter at one meter height among provenances were 7.25% and 12.58%， respectively， indicating that the tree height and diameter at one meter height of the superior cypress tree families were rich in variation among families and provenances， and there was potential for highgeneration breeding. According to the selection rate of 15%， six excellent families for afforestation （Feng 8， Shi 4， Feng 1， Ye 14， Shi 3， and Ye 6） were screened. The average diameter at one meter height， tree height and crown width of the six excellent families were， respectively， 2.97 cm， 3.39 and 0.78 m， which were 18.82%， 12.70% and 15.42% higher than the family average， respectively， and 15.09%， 9.79% and 15.53% higher than the control group， respectively.
Key words Cupressus funebris; Progeny test; Family; Variation; Early selection
Cypress （Cupressus funebris） is one of the subtropical representative conifer species in China. It is an evergreen tall tree in Cupressus of Cupressaceae. The tree has straight trunk with strong adaptability， and is wide in natural distribution. It can adapt to alkaline limestone soil and is an excellent afforestation tree species. It has been widely used in afforestation in southern provinces such as Sichuan， Chongqing， Guizhou and Zhejiang in China. Because of its excellent wood quality， moderate hardness， easy processing， fine and uniform structure， small shrinkage and high corrosion resistance， it is an excellent material for decoration， highgrade furniture， craft carving， plywood and so on. Its good disease resistance and great economic value make it the main renewed tree species for the treatment of pine wood nematode disease and the main tree species that replaces Pinus massoniana. At present， preliminary exploration has been carried out in the construction of seed gardens[1]， seedling raising with light medium[2]and afforestation technology[3-5]， while few studies have been conducted on the breeding of cypress[6-7]. In this study， the growth conditions of progeny test plantations of different superior tree families from different provenances were investigated， and excellent cypress families were initially screened. This study provides data support and research materials for inferior thinning and parental evaluation of the cypress primary clonal seed gardens established using the parents in the later period， upgrading of the seed gardens， and selection and improvement of good materials. Situation of Experiment Field
The experiment was carried out in Diaocaogou Cooperative， in Kele Village， Longsheng Town， Qijiang District， Chongqing City. The area is 380-420 m above the sea level， with an annual average temperature of 17.5， annual precipitation of 1 100 mm， annual relative humidity of 77%-85%， and annual sunshine in the range of 1 100-1 200 h.
Materials and Methods
Experimental materials
The tested superior tree families came from Chongqing and Qiandao Lake in Zhejiang Province. In November 2011， seeds were collected and sown to raise seedlings. In November 2012， the seedlings were planted in accordance with a completely randomized block design with five replicates， each of which included five plants. The 40 superior tree families included 8 from Youyang County， 10 from Zhong County of Chongqing City， 4 from Fengdu County of Chongqing City， and 18 from Qiandao Lake in Zhejiang Province， and the control （CK） was common commodity seeds.
Experimental methods
Growth investigation
In November 2017， after the young forests stopped growing， the growth of three trees randomly selected from each of the five replicates was investigated， including tree height， diameter at one meter height， crown width and growth potential. The tree height and crown width were measured using a steel tape in m， and the reading was reserved with 1 decimal place. The diameter at one meter height （diameter 1 m above the base） was measured with a vernier caliper in cm and the reading was reserved with 2 decimal places. The growth potential was graded according to good， medium and poor， and was scored 3， 2， and 1， respectively.
Data analysis
The data were organized using Excel software. Analysis of variance was performed using SPSS 19.0 software. During the analysis of variance， the growth potential was converted with X to make it conform to the normal distribution.
Results and Analysis
Differences in traits among different superior tree families
The diameter at one meter height， tree height， crown width and growth potential of the test families are shown in Table 1. The results of the variance analysis are shown in Table 2. The results showed that there were significant differences in diameter at one meter height， tree height， crown width and growth potential among families， which provided the possibility for early fastgrowing family selection and excellent parent evaluation. The average diameter at one meter height of the tested families was 2.55 cm; the average tree height was 3.01 m; the average crown width was 0.70 m; and the average growth potential was 1.65. The average diameter at one meter height of the CK was 2.47 cm; the average tree height was 3.00 m; the average crown width was 0.69 m; and the average growth potential was 1.65.
Among them， the top ten of the diameter at one meter height were Feng 8， Shi 4， Kai 8， Feng 1， Ye 14， Feng 2， Leaf 7， Leaf 9， Leaf 6， and Shi 3. The top ten of the tree height growth were Feng 8， Shi 4， Shi 3， leaf 9， Feng 1， leaf 6， leaf 14， Sanhui 5， Shi 7 and You 8. The top ten of the crown width were Shi 4， Sanhui 3， Feng 8， Kai 8， Feng 1 ， Sanhui 4， Ye 14， Zi 3， Ye 6 and Zi 1. The top ten of the growth potential were Shi 4， Kai 8， Ye 14， You 4， Sanhui 5， Jin 3， Long 3， Ye 6， Sanhui 3 and leaf 7.
Differences in traits of superior tree families among different provenances
The diameter at one meter height， tree height， crown width and growth potential values of the four provenances are shown in Table 3. The results of the variance analysis are shown in Table 4. The results showed that the diameter at one meter height， tree height and crown width were the best in Fengdu provenance， which had the average diameter at one meter height， tree height and crown width， respectively， of 3.27 cm， 2.87 and 0.74 m， which were higher than the population average by 7.89%， 11.42% and 6.02%， respectively， and had the growth potential of 1.66， which was 0.41% higher than the population average. The Zhong County provenance had the diameter at one meter height， tree height， crown width and growth potential of 2.80 cm， 2.24 m， 0.64 m and 1.64， respectively， and the Zhejiang provenance had the diameter at one meter height， tree height， crown width and growth potential of 3.11 cm， 2.61 m， 0.71 m and 1.67， respectively. The worst performer was the Fuyang provenance， with diameter at one meter height， tree height， crown width and growth potential being 7.06%， 11.87%， 7.56% and 0.65% lower than those of the Fengdu provenance. The results of variance analysis showed that the diameter at one meter height， tree height and crown width were significantly different between provenances， and the coefficients of variation were 10.25%， 7.19% and 5.91%， respectively， while the growth potential was not significantly different， and the coefficient of variation was 0.98%. Different provenances had significant differences in volume growth， so it is necessary to carry out provenance selection[6-9]. Correlation analysis
Correlation analysis was carried out on diameter at one meter height， tree height， crown width and growth potential. The results are shown in Table 5. The results showed that there were a significant or extremely significant positive correlation between each two of diameter at one meter height， tree height， crown width and growth potential. It indicates that diameter at one meter height， tree height， crown width and growth potential mutually influence each other.
Excellent family selection
Since the progeny test forests were 6yearold saplings， the volume was not calculated. In this experiment， the diameter at one meter height and tree height were selected as the main indicators， and the families also having relatively good crown width and growth potential were selected as excellent families. At the selection rate of 15%， six good cypress families were initially screened （Table 6）. It could be seen from Table 6 that the six selected families showed significant advantages in diameter at one meter height and tree height. The diameter at one meter height and tree height were the best in Feng 8， with a mean value of 3.15 cm and 3.62 m， respectively， which were 26.42% and 22.41% higher than corresponding family average.
Results and Discussion
（1） The differences in tree height， diameter at one meter height， crown width and growth potential of the 6yearold seedlings between the 40 superior tree families reached a significant level， indicating that the breeding space and potential of good cypress varieties in cypress families are very large， and highquality cypress families for afforestation can be screened by selective breeding and other methods.
（2） There were significant differences in tree height， diameter at one meter height and crown width among the four cypress provenances. The coefficients of variation were 10.25%， 7.19% and 5.91%， respectively， while the growth potential varied nonsignificantly and had a coefficient of variation of 0.98%， indicating that among the different provenances， the tree height， ground diameter and crown width were very rich in variation. It is very necessary to carry out provenance selection， and excellent breeding materials can be selected through provenance selection.
（3） According to the selection rate of 15%， six excellent families were selected， namely Feng 8， Shi 4， Feng 1， Ye 14， Shi 3 and Ye 6. The diameter at one meter height was higher than that of the control group by 6.49%-22.35%， respectively; the tree height was 1.86%-19.18% higher than the control group; the crown width was 8.47%-26.74% higher than the control group; and the growth potential was 1.39%-4.59% higher than the control group. It provides valuable basic materials and basis for later good cypress variety breeding， inferior thinning and secondgeneration seed garden establishment. （4） The tree height， diameter at one meter height and crown width of the investigated good cypress progenies had significant differences between the provenances and the families， indicating that it is very necessary to perform provenance and family selection， and using them to carry out highgeneration garden material selection and highgeneration genetic improvement has good potential. Through longterm followup survey， the data of progeny test can provide necessary data support for inferior thinning and parental evaluation of seed gardens established using their parents[1]. In addition， due to the long growth and development period of forest trees， the genetic testing is also long， and the breeding of improved varieties is difficult. In order to shorten the breeding cycle and improve the efficiency of genetic improvement， early selection has always been an important topic for forest breeders. Therefore， in order to select the dominant species of cypress afforestation， carry out excellent parental evaluation and provide a basis for inferior thinning of seed gardens， based on the early selection at early stage， staged observation was carried out on progeny test plantations， and 6yearold progeny test plantations were used to investigate the growth of the forests. The families with good growth status in Chongqing were selected through data comparison and analysis[8-10]， and excellent parents were selected comprehensively according to multiannual survey and analysis.
This study is situated at the stage observation， and the results can provide a theoretical basis for later deforestation and the establishment of secondgeneration seed gardens. However， since the cypress trees were still at the sapling stage with unstable traits， and there was the possibility of misselection， it is necessary to further observe the test materials， so as to select excellent families with good growth and material properties and strong resistance for promotion and application in suitable areas through tracking observation of the growth stages of the excellent families[11-13].
References
[1]JIN GQ， CHEN AM， CHU DY. A technique on establishment and management of clonal seed orchard for Cupressus funebris[J]. China Forestry Science and Technology， 2013， 27（2）： 112-115. （in Chinese）
[2]HE GP， MA JQ， FENG JM， et al. Study on container seedlings cultural techniques with light medium for precious timber tree species， Cupressus funebris[J]. Forest Research， 2010， 23（1）： 134-137. （in Chinese） [3]LIU WH， XU GF， JIN GQ， et al. Thoughts on the status and development of cypress seed garden[J]. Protection Forest Science and Technology， 2011， 6（2）： 1005-5215. （in Chinese）
[4]CHEN CC. Fokienia honginsii seed garden management technology[J]. The Journal of Hebei Forestry Science and Technology， 2010， 3（2）： 1002-3356. （in Chinese）
[5]HUANG XM. Progeny test of plus trees and early selection of Phoebe bournei[J]. Journal of Mountain Agriculture and Biology， 2013， 32（4）： 344-348. （in Chinese）
[6]ZHENG RH， ZOU SR， YANG ZW， et al. Selection and genetic variations of traits among plus trees of Betula luminifera[J]. Journal of Plant Resources and Environment， 2004， （2）： 44-48. （in Chinese）
[7]ZHENG TH. Reselection of fine families of Pinus massoniana[J]. Journal of Fujian College of Forestry， 2003， （2）： 150-154. （in Chinese）
[8]ZHANG XH. Study on genetic variations and selection of seedling growth of Fokienia hodginsii[J]. Hunan Forestry Science & Technology， 2003， （4）： 19-21. （in Chinese）
[9]HUANG DL. Progeny testing of plus trees and selection of Fokienia hodginsii[J]. Journal of Zhejiang Agricultural University， 2009， 26（3）： 449-454. （in Chinese）
[10]ZHANG HY， LI ZL， DING WE， et al. Plustrees progeny testing and family selection of Liquidambar formosana[J]. Guangdong Forestry Science and Technology， 2015， 31（3）： 1006-4427. （in Chinese）
[11]FAN C， ZHOU YG， LI XW， et al. Comparison of soil antierodibility of different modes for reforming low efficiency stands of Cupressus funebris[J]. Scientia Silvae Sinicae， 2014， 50（6）： 1001-7488. （in Chinese）
[12]LOU J， JIN GQ， FENG ZP， et al. Seedling cultivation techniques for clones of Cupressus funebris by cutting[J]. Journal of Zhejiang Forestry Science and Technology， 2014， 34（4）： 1001-3776. （in Chinese）
[13]GONG GT， LI YQ， ZHU ZF， et al. The suitable stand structure and hydrological effects of the cypress protection forests in the central Sichuan hilly region[J]. Acta Ecologica Sinica， 2012， 32（3）： 923-930. （in Chinese）
Key words Cupressus funebris; Progeny test; Family; Variation; Early selection
Cypress （Cupressus funebris） is one of the subtropical representative conifer species in China. It is an evergreen tall tree in Cupressus of Cupressaceae. The tree has straight trunk with strong adaptability， and is wide in natural distribution. It can adapt to alkaline limestone soil and is an excellent afforestation tree species. It has been widely used in afforestation in southern provinces such as Sichuan， Chongqing， Guizhou and Zhejiang in China. Because of its excellent wood quality， moderate hardness， easy processing， fine and uniform structure， small shrinkage and high corrosion resistance， it is an excellent material for decoration， highgrade furniture， craft carving， plywood and so on. Its good disease resistance and great economic value make it the main renewed tree species for the treatment of pine wood nematode disease and the main tree species that replaces Pinus massoniana. At present， preliminary exploration has been carried out in the construction of seed gardens[1]， seedling raising with light medium[2]and afforestation technology[3-5]， while few studies have been conducted on the breeding of cypress[6-7]. In this study， the growth conditions of progeny test plantations of different superior tree families from different provenances were investigated， and excellent cypress families were initially screened. This study provides data support and research materials for inferior thinning and parental evaluation of the cypress primary clonal seed gardens established using the parents in the later period， upgrading of the seed gardens， and selection and improvement of good materials. Situation of Experiment Field
The experiment was carried out in Diaocaogou Cooperative， in Kele Village， Longsheng Town， Qijiang District， Chongqing City. The area is 380-420 m above the sea level， with an annual average temperature of 17.5， annual precipitation of 1 100 mm， annual relative humidity of 77%-85%， and annual sunshine in the range of 1 100-1 200 h.
Materials and Methods
Experimental materials
The tested superior tree families came from Chongqing and Qiandao Lake in Zhejiang Province. In November 2011， seeds were collected and sown to raise seedlings. In November 2012， the seedlings were planted in accordance with a completely randomized block design with five replicates， each of which included five plants. The 40 superior tree families included 8 from Youyang County， 10 from Zhong County of Chongqing City， 4 from Fengdu County of Chongqing City， and 18 from Qiandao Lake in Zhejiang Province， and the control （CK） was common commodity seeds.
Experimental methods
Growth investigation
In November 2017， after the young forests stopped growing， the growth of three trees randomly selected from each of the five replicates was investigated， including tree height， diameter at one meter height， crown width and growth potential. The tree height and crown width were measured using a steel tape in m， and the reading was reserved with 1 decimal place. The diameter at one meter height （diameter 1 m above the base） was measured with a vernier caliper in cm and the reading was reserved with 2 decimal places. The growth potential was graded according to good， medium and poor， and was scored 3， 2， and 1， respectively.
Data analysis
The data were organized using Excel software. Analysis of variance was performed using SPSS 19.0 software. During the analysis of variance， the growth potential was converted with X to make it conform to the normal distribution.
Results and Analysis
Differences in traits among different superior tree families
The diameter at one meter height， tree height， crown width and growth potential of the test families are shown in Table 1. The results of the variance analysis are shown in Table 2. The results showed that there were significant differences in diameter at one meter height， tree height， crown width and growth potential among families， which provided the possibility for early fastgrowing family selection and excellent parent evaluation. The average diameter at one meter height of the tested families was 2.55 cm; the average tree height was 3.01 m; the average crown width was 0.70 m; and the average growth potential was 1.65. The average diameter at one meter height of the CK was 2.47 cm; the average tree height was 3.00 m; the average crown width was 0.69 m; and the average growth potential was 1.65.
Among them， the top ten of the diameter at one meter height were Feng 8， Shi 4， Kai 8， Feng 1， Ye 14， Feng 2， Leaf 7， Leaf 9， Leaf 6， and Shi 3. The top ten of the tree height growth were Feng 8， Shi 4， Shi 3， leaf 9， Feng 1， leaf 6， leaf 14， Sanhui 5， Shi 7 and You 8. The top ten of the crown width were Shi 4， Sanhui 3， Feng 8， Kai 8， Feng 1 ， Sanhui 4， Ye 14， Zi 3， Ye 6 and Zi 1. The top ten of the growth potential were Shi 4， Kai 8， Ye 14， You 4， Sanhui 5， Jin 3， Long 3， Ye 6， Sanhui 3 and leaf 7.
Differences in traits of superior tree families among different provenances
The diameter at one meter height， tree height， crown width and growth potential values of the four provenances are shown in Table 3. The results of the variance analysis are shown in Table 4. The results showed that the diameter at one meter height， tree height and crown width were the best in Fengdu provenance， which had the average diameter at one meter height， tree height and crown width， respectively， of 3.27 cm， 2.87 and 0.74 m， which were higher than the population average by 7.89%， 11.42% and 6.02%， respectively， and had the growth potential of 1.66， which was 0.41% higher than the population average. The Zhong County provenance had the diameter at one meter height， tree height， crown width and growth potential of 2.80 cm， 2.24 m， 0.64 m and 1.64， respectively， and the Zhejiang provenance had the diameter at one meter height， tree height， crown width and growth potential of 3.11 cm， 2.61 m， 0.71 m and 1.67， respectively. The worst performer was the Fuyang provenance， with diameter at one meter height， tree height， crown width and growth potential being 7.06%， 11.87%， 7.56% and 0.65% lower than those of the Fengdu provenance. The results of variance analysis showed that the diameter at one meter height， tree height and crown width were significantly different between provenances， and the coefficients of variation were 10.25%， 7.19% and 5.91%， respectively， while the growth potential was not significantly different， and the coefficient of variation was 0.98%. Different provenances had significant differences in volume growth， so it is necessary to carry out provenance selection[6-9]. Correlation analysis
Correlation analysis was carried out on diameter at one meter height， tree height， crown width and growth potential. The results are shown in Table 5. The results showed that there were a significant or extremely significant positive correlation between each two of diameter at one meter height， tree height， crown width and growth potential. It indicates that diameter at one meter height， tree height， crown width and growth potential mutually influence each other.
Excellent family selection
Since the progeny test forests were 6yearold saplings， the volume was not calculated. In this experiment， the diameter at one meter height and tree height were selected as the main indicators， and the families also having relatively good crown width and growth potential were selected as excellent families. At the selection rate of 15%， six good cypress families were initially screened （Table 6）. It could be seen from Table 6 that the six selected families showed significant advantages in diameter at one meter height and tree height. The diameter at one meter height and tree height were the best in Feng 8， with a mean value of 3.15 cm and 3.62 m， respectively， which were 26.42% and 22.41% higher than corresponding family average.
Results and Discussion
（1） The differences in tree height， diameter at one meter height， crown width and growth potential of the 6yearold seedlings between the 40 superior tree families reached a significant level， indicating that the breeding space and potential of good cypress varieties in cypress families are very large， and highquality cypress families for afforestation can be screened by selective breeding and other methods.
（2） There were significant differences in tree height， diameter at one meter height and crown width among the four cypress provenances. The coefficients of variation were 10.25%， 7.19% and 5.91%， respectively， while the growth potential varied nonsignificantly and had a coefficient of variation of 0.98%， indicating that among the different provenances， the tree height， ground diameter and crown width were very rich in variation. It is very necessary to carry out provenance selection， and excellent breeding materials can be selected through provenance selection.
（3） According to the selection rate of 15%， six excellent families were selected， namely Feng 8， Shi 4， Feng 1， Ye 14， Shi 3 and Ye 6. The diameter at one meter height was higher than that of the control group by 6.49%-22.35%， respectively; the tree height was 1.86%-19.18% higher than the control group; the crown width was 8.47%-26.74% higher than the control group; and the growth potential was 1.39%-4.59% higher than the control group. It provides valuable basic materials and basis for later good cypress variety breeding， inferior thinning and secondgeneration seed garden establishment. （4） The tree height， diameter at one meter height and crown width of the investigated good cypress progenies had significant differences between the provenances and the families， indicating that it is very necessary to perform provenance and family selection， and using them to carry out highgeneration garden material selection and highgeneration genetic improvement has good potential. Through longterm followup survey， the data of progeny test can provide necessary data support for inferior thinning and parental evaluation of seed gardens established using their parents[1]. In addition， due to the long growth and development period of forest trees， the genetic testing is also long， and the breeding of improved varieties is difficult. In order to shorten the breeding cycle and improve the efficiency of genetic improvement， early selection has always been an important topic for forest breeders. Therefore， in order to select the dominant species of cypress afforestation， carry out excellent parental evaluation and provide a basis for inferior thinning of seed gardens， based on the early selection at early stage， staged observation was carried out on progeny test plantations， and 6yearold progeny test plantations were used to investigate the growth of the forests. The families with good growth status in Chongqing were selected through data comparison and analysis[8-10]， and excellent parents were selected comprehensively according to multiannual survey and analysis.
This study is situated at the stage observation， and the results can provide a theoretical basis for later deforestation and the establishment of secondgeneration seed gardens. However， since the cypress trees were still at the sapling stage with unstable traits， and there was the possibility of misselection， it is necessary to further observe the test materials， so as to select excellent families with good growth and material properties and strong resistance for promotion and application in suitable areas through tracking observation of the growth stages of the excellent families[11-13].
References
[1]JIN GQ， CHEN AM， CHU DY. A technique on establishment and management of clonal seed orchard for Cupressus funebris[J]. China Forestry Science and Technology， 2013， 27（2）： 112-115. （in Chinese）
[2]HE GP， MA JQ， FENG JM， et al. Study on container seedlings cultural techniques with light medium for precious timber tree species， Cupressus funebris[J]. Forest Research， 2010， 23（1）： 134-137. （in Chinese） [3]LIU WH， XU GF， JIN GQ， et al. Thoughts on the status and development of cypress seed garden[J]. Protection Forest Science and Technology， 2011， 6（2）： 1005-5215. （in Chinese）
[4]CHEN CC. Fokienia honginsii seed garden management technology[J]. The Journal of Hebei Forestry Science and Technology， 2010， 3（2）： 1002-3356. （in Chinese）
[5]HUANG XM. Progeny test of plus trees and early selection of Phoebe bournei[J]. Journal of Mountain Agriculture and Biology， 2013， 32（4）： 344-348. （in Chinese）
[6]ZHENG RH， ZOU SR， YANG ZW， et al. Selection and genetic variations of traits among plus trees of Betula luminifera[J]. Journal of Plant Resources and Environment， 2004， （2）： 44-48. （in Chinese）
[7]ZHENG TH. Reselection of fine families of Pinus massoniana[J]. Journal of Fujian College of Forestry， 2003， （2）： 150-154. （in Chinese）
[8]ZHANG XH. Study on genetic variations and selection of seedling growth of Fokienia hodginsii[J]. Hunan Forestry Science & Technology， 2003， （4）： 19-21. （in Chinese）
[9]HUANG DL. Progeny testing of plus trees and selection of Fokienia hodginsii[J]. Journal of Zhejiang Agricultural University， 2009， 26（3）： 449-454. （in Chinese）
[10]ZHANG HY， LI ZL， DING WE， et al. Plustrees progeny testing and family selection of Liquidambar formosana[J]. Guangdong Forestry Science and Technology， 2015， 31（3）： 1006-4427. （in Chinese）
[11]FAN C， ZHOU YG， LI XW， et al. Comparison of soil antierodibility of different modes for reforming low efficiency stands of Cupressus funebris[J]. Scientia Silvae Sinicae， 2014， 50（6）： 1001-7488. （in Chinese）
[12]LOU J， JIN GQ， FENG ZP， et al. Seedling cultivation techniques for clones of Cupressus funebris by cutting[J]. Journal of Zhejiang Forestry Science and Technology， 2014， 34（4）： 1001-3776. （in Chinese）
[13]GONG GT， LI YQ， ZHU ZF， et al. The suitable stand structure and hydrological effects of the cypress protection forests in the central Sichuan hilly region[J]. Acta Ecologica Sinica， 2012， 32（3）： 923-930. （in Chinese）