4_Conventional_Breeding

International poplar symposium Ⅳ Nanjing, China. 2006

Session Ⅱ
Advances In Conventional
Poplar Breeding and
Gene Conservation

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International poplar symposium Ⅳ Nanjing, China. 2006

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International poplar symposium Ⅳ Nanjing, China. 2006

A case study on the Genotype Environment interaction of poplar
Growth
Huogen Li 1, Huixin Pan 1, Shunzhang Cai 2, Xiangjin Yan 3, Hefeng Xie 4
1)
2)
3)
4)

Nanjing Forestry University, Nanjing, 210037
Baoying Multiple management Bureau of Jiangsu Province, Baoying,
Siyang Multiple management Bureau of Jiangsu Province, Siyang,
Forest seed & seedling center, Shandong Forestry department, Jinan,

A significant difference was found existed among clones based on the analyses of variance

of growth traits such as DBH, height and volume of 80 11-year-old Eastern cottonwood clones.
The broad-sense heritability of DBH, height and volume were 30.7%, 20.4% and 32%
respectively. The result indicated that it is possible to select excellent clones among the clone
population. A elementary evaluation was made to each clone under the comprehensive
consideration of growth, stem form, and then several superior clones such as clones I-69,
S3412, S3239 and S3240 were picked out as the potential varieties.
The genotype-environment interaction of the growth was analyzed based on the
investigation of 12 cottonwood clones from 3 clone testing plantations situated at Xu Zhou and
Bao Ying in Jiang Su province, and Ning Yang, Shan Dong province. The conclusion showed
that the genotype-environment interaction was extremely remarkable. In order to guide their
extension in the future, the genetic stability and adaptation of 12 clones were also explored.
Keywords: Eastern cottonwood, Genotype Environment interaction, Genetic stability,
Heritablity.

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International poplar symposium Ⅳ Nanjing, China. 2006

A Mechanistic Framework for Characterizing the Genetic
Architecture of Biomass Partitioning
Rongling Wu and Song Wu
Department of Statistics, University of Florida, Gainesville, FL 32611, USA

The shapes and sizes of living things can be explained in terms of biological, chemical and
physical processes. Yet, the genetic mechanisms underlying patterns in the shapes and sizes of
plants and animals through these processes have been poorly understood. In this talk, we will
present a statistical framework for characterizing the genetic architecture of morphological
variation in allometrical shape with genetic linkage maps. This framework is incorporated by
mechanistic global allocation rules for patterns of biomass partitioning, allowing quantitative

tests of the interplay between genetic actions and development shape. The framework model
has been validated through simulation studies and a real example for poplar trees. The proposed
model will have great implications for understanding the genetic regulation of morphological
shape and development and, ultimately, providing scientific guidance for the selection of
ideotypes that display optimal resource use efficiency in agriculture and forestry.

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International poplar symposium Ⅳ Nanjing, China. 2006

AN OVERVIEW OF CURRENT ASPEN AND POPLAR BREEDING IN
CANADA
Thomas, B.R.
Genstat Consulting, Box 45086, Lansdowne Postal Outlet, Edmonton, Alberta T6H-5Y1. Email:
, Fax/Phone: 780-432-4230.

In this presentation I will provide a brief overview of aspen and poplar work to date in
Canada and then provide a much more in-depth description of the current programs. The most
active areas for tree breeding in poplars is currently focused on the boreal and grassland fringe
regions of the prairie provinces of western Canada as well, there is a long-term on-going
program in the province of Quebec.
Industrial participation and needs are driving much of the work in the prairies with some
Federal Government collaboration, while the eastern program in Quebec is run primarily by the
Provincial Government. There is an increasing realization in these traditional tree breeding
programs and active work within the Poplar Council of Canada of the need to bring the
molecular tools available through the sequencing of the poplar genome, to assist with rapid
selection and screening in these operational end-user focused programs.
As the need for a guaranteed fibre supply for pulp and plywood, and options for alternative
energy and reclamation tools for phytoremediation expand, the traditional uses of hybrid

poplars for shelterbelts around farm fields and riparian plantings along stream or pond edges,
no longer drives the primary focus in these programs. Collaborations have developed that
support breeding programs where each partner may have a different end-use in mind, but with
the diversity of genetic stock that can be produced through hybrid breeding, many objectives
can be met within a single program. Time-permitting, details of specific programs will also be
discussed.

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International poplar symposium Ⅳ Nanjing, China. 2006

CONSERVING THE GENETIC RESOURCES OF POPULUS SSP. IN PAIN
N. Alba(1), H. Sixto(1), C. Maestro(2), J. L. Puelas(3), S. C. González-Martínez (1), R. Alía(1)
(1) Dpt. Resources and Systems Forestry. CIFOR-INIA, (2) Forest Resources Unit. Centre
for Research and Technology Agrarian (CITA-DGA) (3) National Centre for
improvement and genetic conservation of forest genetic resources.

The need to conserve the genetic resources of our native poplars is reflected in the
different initiatives being developed by both central and local government. The European
program for the conservation of forest genetic resources (EUFORGEN) aims to implement both
in situ and ex situ conservation strategies.
Until now, the ex situ initiatives in Spain have involved the installation and maintenance of
collections of P. alba, P. nigra and P. tremula.
The P. alba collection is located in the National Centre for Forest Genetic Improvement
"El Serranillo” (Guadalajara) belongs to DGB (Environment Ministry). It is made up of 24
families and more than 400 clones which are kept as stool beds, and an arboretum with about
300 clones. The P. alba accessions from Ebro Basin are duplicated in CITA (Saragossa). The
work undertaken focuses on the study of genetic variation through isoenzymes, morphology,
and growth habit. Some studies focused on in situ conservation strategies aim at genetic flow,

species’ regenaration strategies, adaptive differentiation between sex morhs and ISPs
establishment.
The P. tremula collection, installed in the DGB nurseries is the result of an agreement
between INIA and DGB. It comprises more than 50 clones, propagated using ‘in vitro’
techniques. This collection is currently kept in an arboretum that was located at “Valsaín”
(Segovia).
The Spanish collection of P. nigra is located at the CITA-DGA (Saragossa) and at CIFORINIA (Madrid). Bothd sites comprised more than 325 accessions, from Ebro Basin populations
mainly, where the specie presence is more frequent. Clones from Tajo and Duero Basins (where
the species’ area is smaller) are also present. The P. nigra Spanish collection is kept (totally or
partially) in arboretums and stood beds. Ebro clones from installed in DGA (Saragossa)
andthose from Duero and Tajo were installed in INIA and DGB (Madrid, Guadalajara and
Segovia). Studies using different molecular markers (Isoenzymes, Microsatellites and AFLP´s)
and morphological characterization show that Spanish P. nigra populations maintain a high
level of genetic diversity.
•The establishment of an in situ and ex situ conservation strategy requires an in-depth
study into the diversity of the species in question. The use of molecular markers is one of the
tools available for this purpose, jointly with adaptive and morphological studies.
•The conservation methods established within the EUFORGEN workgroups had facilitate
the development of this task in our country as well as promoting the exchange of both knowhow and resources.
•Although ex situ conservation work is to some extent under way, with the establishment

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International poplar symposium Ⅳ Nanjing, China. 2006

of collections and the initiation of evaluation and characterisation studies, the same cannot be
said for in situ conservation for which stand characterisation, selection and management are
necessary to further this objective. Managing the riverside is fundamental to the in situ
conservation of resources of these species. Therefore managers must be provided with the

necessary tools and guidelines.

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International poplar symposium Ⅳ Nanjing, China. 2006

Directive selection ， development and popularization of new
Populus varieties for industrial wood plantation in northern China
Zhang Qi-wen Li Jin-hua
Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, P R China
Email: Fax:+86-10-62872015

In China, there are large area of poplar plantation with low commercial value of cultivars.
In order to meet the increasing need for industrial wood, we undertook the key project of poplar
genetic and improvement which mainly focus on clones of Section Aigeiros. After
hybridization, introduction and selection of poplar breeding for more than fifteen years, we
finally got most super cultivars for the plain area in Northern China, No.107 (P. euramericana
cv ‘Neva’), No.108 (P. euramericana cv ‘Guariento’), No.111 (P. euramericana cv ‘Bellotto’),
No.110 (P. deltoides ×P. maximowiczii cv ‘Eridano’). These cultivars perform well with fast
growing rate, high quality wood, straight trunk, narrow crown and have strong resistance. Wood
growing rate of ‘Neva’ and ‘Guariento’ increase 60 percent than the comparison cultivar, I-214
(P. euramericana cv ‘I-214’). After the certification of national register authority as poplar
cultivars, ‘Neva’ and ‘Guariento’ were planted spreading in 14 provinces and regions mainly on
medium plain of Northern China. The size of total area was 18.37 million hectare. On condition
of intensive management, wood yield of plantation with two cultivars was between 25.5 and
46.5 cubic meter per hectare each year and increased between 13.5 and 21 cubic meter per
hectare each year than that of I-214. Wood increase of all plantation was between 1653 and
2572 cubic meter, showing considerable commercial benefit.
On aspect of selection and development of new poplar cultivars for industrial wood, there

were methods and results as these as following. Firstly, twice silviculture and strictly screening
with several steps from Italy poplar selection procedure improved coefficient of clonal
selection. Secondly, multitraits selection with growth, wood quality, trunk and crown ensured
directional selection of poplar cultivars for industrial wood. Thirdly, appropriate time of
selection age would be between 4- and 7-year-old for paper pulp wood, which have faster
growth rate, more wood density, longer fiber and fewer extracts of 1% NaOH. Fourthly, clonal
fingerprinting of two cultivars of Section Ageiros were established by AFLP DNA marker,
which could be useful in identification, registration of cultivars. Lastly, APMP puly assay with
wood of ‘Neva’ showed it was qulity wood for pulp, which laid a foundation for integrative
poplar plantation-paper industry.
Key words: poplar, Populus, new cultivars, fast-growing and high-yield plantation, genetic
improvement, popularization.

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International poplar symposium Ⅳ Nanjing, China. 2006

Field test of introduced new poplar clones
QIN Guang-hua1, JIANG Yue-zhong1, QIAO Yu-ling1, B. Nottola2
1

Shandong Academy of Forestry, Jinan 250014, P. R. China
Societa Agricola E Forestale per Le Plante (S. P. A), Roma 00153, Italy

2

Poplar is one of the dominant tree species for the establishment of fast growing plantations
in Shandong Province. Eighteen poplar clones belonging to Populus aigeiros Section were
introduced from Italy, Turkey and domestic regions. Populus deltoides cv. ‘Lux’ I-69/55 (I-69),

which was widely used in Shandong Province, China, was taken as control clone. Following a
randomized complete block design, seedling test and controlled afforestation trials were carried
out at Juxian County, Caoxian County and Laiyang city. The results showed that the poplar
clone (Populus × euramericana cv. ‘102/74’), namely 102/74, performed well both in terms of
adaptability and growth rate. The mean height (H) (13.9 m), diameter at breast height (DBH)
(18.0 cm) and volume growth (V) (0.1445 m 3 ) were, were 2.2 %, 21.6% and 52.9 % higher
than those of I-69 (CK), respectively, at the age of 5 years at three experimental sites.
Moreover, the clone can be propagated easily and showed high resistance to poplar disease, pest
as well as salinity and had longer growing period. Furthermore, wood basic density and fiber
length of new poplar clone (102/74) were as same as I-69 (CK). It was concluded that the
selected clone (102/74) was ideal for the establishment of fast-growing poplar plantations,
especially for the pulpwood plantations in Shandong Province.
Keywords: Poplar, Clones; Introduction; Selection

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International poplar symposium Ⅳ Nanjing, China. 2006

Genetic Analysis on Growth and Wood Properties
Comprehensive Selection of Populus deltoides Clones

and

Tang Yuxi1，2 Wu Lixun2 Wu Min2 Xu Shifeng2 Tang Jie2
1 Central South Forestry University Changsha 410004 2 Hunan Academy of Forestry Changsha
410004

According to the 6-year-old data of 18 populus deltoides clones，the genetic variation and
correlations between growth and wood properties were studied. Besides fiber content and fiber

length，the clone effect was highly significant for other 6 traits such as DBH，height，individual
stem volume， fiber width， ratio of fiber length to width，wood basic density. The broad-sense
heritabilities ranged from 0.6109 to 0.9053 ， it indicated that the variations of 6 traits were
moderately or intensively inherited. The inheritances of growth characters and wood properties
were independent，as pulp-making material，the improvement of growth traits should regarded
as the premise. By using Gray Related Analysis，5 new hybrid P. deltoides clones with excellent
comprehensive traits were selected ， especially ， P. deltoides cl.‘xianglin 90’ and P. deltoids
cl.‘xianglin 77’ were outstanding among them. Compared with P. deltoids cv.‘I-69/55’ ， the
individual stem volume respectively improved 60.71% ， 46.45% ， and the individual fiber
production respectively improved 51.43%，44.13%.
Key words: Genetic variation ， Gray Related Analysis ， Comprehensive selection ， Populus
deltoides Clones

Genetic differentiation of Black Cottonwood, P. trichocarpa Torrey
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International poplar symposium Ⅳ Nanjing, China. 2006

& Gray in British Columbia
Ying, Cheng C., Xie, Chang-Yi, Holowachuk, Diane, and Yanchuk, Alvin
RESEARCH BRANCH, BRITISH COLUMBIA MINISTRY OF FORESTS AND RANGE, 1 ST FLOOR, 722.
JOHNSON ST., VICTORIA, B. C. 9519 STN PROV GOVT VICTORIA BC V8W 9C2 BRITISH COLUMBIA,
CANADA.

Genetic differentiation of black cottonwood in British Columbia was studied in a commongarden environment. A total of 835 clones from 181 provenances along 36 drainages were
tested for three years and the assessed traits include height growth, abnormal leaf flushing, and
leaf disease (Salsa sordida and Melampsora occidentalis ) infection. Results revealed a sharp
north-south regional differentiation in all the assessed traits. Northern populations demonstrated
severe mal-adaptation in the southern environment at the test site. Besides natural selection,

restricted gene flow along a “no-cottonwood” belt may also have played a significant role in
shaping the observed pattern of geographic differentiation. Trees from Lower Fraser River and
Nechako River – Upper Fraser River drainages not only demonstrated outstanding growth but
also were relatively free of diseases or abnormal flushing, suggesting those areas may have the
best source of materials for selection and breeding.

Genetic

Variation

of

Three

Populus
69

euramericana

Clones


International poplar symposium Ⅳ Nanjing, China. 2006

Anatomical, Physiological and Growth Traits
Zhengtian Niu， Qiwen Zhang*， Jinhua Li，Zhenyuan Sun
Institute of Forestry, Chinese Academy of forestry， Beijing 100091
Phone : 010-62889600 Email，

Anatomical and physiological characteristics related with biomass of rooted cuttings of 3

Populus canadensis genotypes were evaluated in a controlled pot test in the field experiment.
Measurements were taken on the net photosynthesis rate, intercellular CO 2 Concentration,
transpiration rate, Stomatal conductance, Stomatal length,stomatal density on both side of the
blade, the thickness of palisade tissue and spongy mesophy(II), leaf area, leaf length, leaf fresh
mass and specific dry mass. Total height, basal diameter, and above-ground biomass were
measured after 8 months. The results showed that the three clones growth exhibit significant
inter-clonal variability, which are mainly from clones different genotype. Stomatal length,
stomatal density on abaxial side of the blade, the thickness of palisade tissue, leaf area and leaf
length characteristics exhibited a high degree of statistically significant inter-clonal variability,
indicative strong genetic control. Strong correlations were observed between: 1) Height, basal
diameter and biomass with each other. 2)The number of stomata on abaxial leaf surface and
stomatal length with height, basal diameter and biomass, 3) The thickness of the palisade leaf
layer with height, basal diameter and biomass, 4) Leaf area, leaf length with height basal
diameter and biomass. The results indicate that abaxial stomata number, thickness of the
palisade tissue, leaf area and leaf length may be useful selection criteria in the identification
of genotypes with economic traits. The results may be useful for marker-assisted breeding.
Construction of high yielding hybrid ideotype with desirable anatomical features was
considered to be feasible.
Key words: Populus canadensis Clone, Anatomy, Physiology, Variance, Correlation, Selection,

Induction of Triploids in White Poplar
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International poplar symposium Ⅳ Nanjing, China. 2006

Kang Xiang-yang(1) Zhang Jin-feng(1) Zhang Ping-dong(1) Li Yan-hua(1)
(1) Institute for Chinese White Poplar,
/Fax: 0086-10-62338013

Beijing

Forestry

University,

P

R

China,

Trees with polyploidy general display characteristics of heterosis over normal diploids.
For example, triploid poplar trees not only grow fast but also have low lignin and high cellulose
content because of the giant cellulose cell minus the cell number and surface within a certain
volume timber. Thus selection and production of triploid poplar trees can produce more paper
and other fiber products that benefit the forest industry. In recent years, using white poplar
Populus tomentosa, ，P. tomentosa×P.bolleana，and (P. alba×P. glandulosa) as material, we
have studied the mechanism and developed the technique for inducing triploid trees. Several
steps were involved in the induction of triploid poplar trees. First, the best treatment stages for
obtaining 2n white poplar pollen were in the pachynema or diakinesis of meiosis when buds
were treated with colchicines solution or high temperature. The 2n pollen rate can be more than
80% if white poplar male buds were treated on right stage. The 2n pollen vitality and its
germination process were observed and counted by live fertilization test. The 1n pollen in the
pollen mix was used as a check because it was much smaller than the 2n pollen and easy to
observe. The 2n pollen germinated slowly than the 1n pollen, which was the main reason for
obtaining low success rate of triploid plants because of the poor competition of 2n pollen in the
process of fertilization. However, the germination of 2n pollen can be greatly increased and
thus produce much higher percent triploid plants (30 times) compared to the normal hybrid
filial population when the mixed pollen was treated with 60Co radial. The 1n pollen was more

sensitive than the 2n pollen when the mixed pollen powder was exposed to the radiation. The
meiosis process of megaspore was difficult to observe. The microspore was exploited as a
check according to the development time relative to each other. A method was used for
comparatively judgment the effective treatment stage of the chromosome doubling of the
megaspore. The megaspore of P.tomentosa×P.bolleana and Populus alba×P.glandulosa was in
pachynema or diakinesis of meiosis while its microspore was in the stage of pollen cell with a
single nuclear in the side of cell wall when those two flower branches began to water cultured
at same time. The percent triploid plant can reach 16.7% when the female flower buds were
treated with colchicines solution at the time of male flower buds in the stage of pollen cell with
a single nuclear in the side of cell wall. A new triploid white poplar inducing technique was
discovered. That is the female flowers were treated with colchicines solution after pollination.
The success rate for triploid plant could reach 57.1% when the female flowers of
P.tomentosa×P.bolleana and Populus alba×P.glandulosa were treated with colchicines solution
after pollinated 24h to 36h. These studies of poplar chromosome doubling and triploid
inducing will have important reference value for enlarging the triploid parents resources and
increasing the population number of triploid plants and other similar tree specie polyploid
breeding.
Key words: poplar, chromosome double, colchicines, effective treatment stage, triploid

Induction of triploid white poplars by chromosome doubling of the
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International poplar symposium Ⅳ Nanjing, China. 2006

female gamete of Populous alba × P. glandulosa
Y. H. Li(1), X. Y. Kang (1), Z. H. Zhang (1), H. G. Chen (1)
1), Key Laboratory for Genetics and Breeding of Forest Trees and Ornamental Plants, Ministry of
Education, Beijing Forestry University, Beijing 100083, China.

In triploid poplar breeding, an improved technology was suggested that triploids was
induced by chromosome doubling of female gamete. 2n female gametes has competitive
advantage over 2n 2npollen in fertilization. Triploid plants could be obtained immediately after
fertilization events. However, meiosis of the megaspore mother cells is difficult to observe
quickly. Cytological studies found that the meiosis stages of megaspores and microspores of
Populous alba × P. glandulosa were closely correlated in their development. So meiosis of the
megaspore mother cells could be judgment timely by observing meiosis of microspores.
Chromosome doubling could be achieved in an effective colchicines-induced stage. The
frequency of triploids has been increased. Microscopic examination was employed to found that
meiosis of microspore mother cells of P. alba × P. glandulosa developed into monokaryotic
pollen at mitosis metaphase and into the stage of pollen cell with a single nuclear in the side of
cell wall, meiosis of megaspore mother cells was in the bouquet stage and pachytene,
Temporality , the female buds were dipped in the bottle of a 0.5% solution of colchicine. Then
hand pollination with the n pollen of P. tomentosa. The highest percentage of triploids was
16.7%. It is helpful to tree ployploid breeding.

Meiosis and Chromosome Behaviours of Pollen Mother Cells in
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International poplar symposium Ⅳ Nanjing, China. 2006

Populus simonii Carr. × P. nigra L. ‘Tongliao’
H. Zhang, P. D. Zhang
Key Laboratory for Genetics and Breeding of Forest Trees and Ornamental Plants, Ministry of
Education. Beijing Forestry University, 100083, P. R. China.

The meiotic process and chromosome behaviours of pollen mother cells are studied in
Populus simonii Carr. × P. nigra L. ‘Tongliao’ cultured in greenhouse. The meiotic stages have
close relation to the observing features of the male flower buds and the color of anthers.

ProphaseⅠ occupies about 90 ， time for the whole meiotic process. There are several univalents
in metaphaseⅠ, lagging chromosomes in anaphaseⅠ and natural large pollens in P. simonii × P.
nigra ‘Tongliao’, due to its high heterozygosity of genetics. Two nucleoli in prophase Ⅰ and
eight nucleoli in one daughter nucleus of telophaseⅠ and Ⅱ are observed, and the multi-nucleoli
may be relative to the paleopolyploid origin of the genus Populus L.. After late leptotene, five
to nine different phases can be observed usually in the same flower bud or the same flower even
in the same anther. The asynchronism of meiotic process may be an evolutionary compromise
adapting the local conditions, and important for propagation of populations.
Key words: Populus simonii Carr. × P. nigra L. ‘Tongliao’, pollen mother cell, meiotic stage,
heterozygosity, multi-nucleoli, large pollen

Morphological diversity of black hairy poplar (Populus nigra
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International poplar symposium Ⅳ Nanjing, China. 2006

subsp. caudina) in Bosnia and Herzegovina
Ballian D. 1,Kajba D.2, Idzojtic M. 2
1

University of Sarajevo, Bosnia and Herzegovina
University of Zagreb, Croatia

2

Hairy type of black poplar is typical for Sub-Mediterranean area of Bosnia and
Herzegovina, the Valley of Neretva River in particular, where this species is mainly distributed
in its lower flow, the population of Čapljina, and a smaller population at the mouth of the
Trešanička River to Neretva River in its middle flow. The population of Konjic, as well as the

basin of the Vrbas River, which is separated by a mountain chain of Makljen from the Nerteva
population, belongs to the population of Bugojno.
This species may, in the future, play a significant role, particularly within the processes of
global heating, because in its natural habitat it can stand well high temperatures.
The target of this study is to determine the level of variability and to try to determine the
correlation between these three populations by usage of morphologic markers and statistical
analysis. The herbarium material, from the three listed populations, has been collected for this
study, that is, 50 leaves from the trees, taken from the southern orientation of the tree crown,
and its central part, only from the short fertile shoots. We analyzed five characteristics: the leaf
blade length, the leaf blade width, the petiole length, the angle between the first lower lateral
vein and the midrib, and the distance between the widest part of the leaf and the leaf base.
The obtained results showed that the analyzed sizes point at presence of differences among
the populations. Thus, with the descriptive analysis there were demonstrated differences
between the populations of Čapljina, on one side, and the populations of Konjic and Bugojno
on the other. Apart from the descriptive analysis that has been carried out, we have also done a
cluster analysis that showed grouping to two bigger clusters, Čapljina on one side, and Konjic
and Bugojno on the other. Between them there is however a relationship, thus the trees number
9, from the Čapljina and Konjic population, showed closeness by cluster analysis. This
closeness points at previous relationship of the analyzed populations, and that this is a matter of
their historical separation, along with specific paths of further development, under possibly
very strong anthropogenic influence within the period of last 2000 years.
Key words: Populus nigra subsp. caudina, Hairy black poplar, morfological

Populus deltoides CV.“zhonghong”—Colored leaf upstart of the
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International poplar symposium Ⅳ Nanjing, China. 2006

ornamental city

Zhu Yanlin
Henan Academy of Forestry, Zhengzhou 450008, Henan Province, P. R China

Populus deltoides CV.“zhonghong” ， as a bud mutant of Poplar deltoids ， was found by
scientific workers of the Forestry Academy of Henan in 2000 in Shangqiu Henan. It had been
approved by the Henan Inspection Committee of Superior Tree Species in March 2006.
The stem form of Populus deltoides CV.“zhonghong” is perfectly straight and orbicular,
which is male and doesn’t fly garrulous. The internode length is 3-5cm. The leaf width is 1223cm, and length is 12-25cm and the leaf area is smaller than Poplar 2025 obviously. The bud
is ovoid which surface cling to viscosity. The top of the bud is very red. The angle between the
buds of the top stem and stem is less than 15°,but the lower buds are small which cling to stem
closely. The figure of the leaves that have blunt sawtoothed edges is equilateral triangle or
triangle. The petiole which is flat and costate are mauve.The branch or stem which don’t lignify
totally are mauve in growing season. The lower part of the annual stem is ashen after which leaf
fall, but the top 50-70cm is brown. The lenticel is white, long cylindrical and round, which
distribut evenly. The raised angle of bud is more obvious. The middle arris of the middle or
lower bud of annual stem extend generally to internode and link up with the mark among
internodes.
In Shangqiu Henan, Populus deltoides CV.“zhonghong” sprout during March 30 to April
3,which is earlier 6-9days than Poplar Zhonglin-46, earlier 3-5days than Poplar Zhonglin-69
and later 3-4days than Poplar 2025. The top is closured between Sep18-24. The leaf falling is
done between Oct28 to Nov5, which is later about 15days than Poplar Zhonglin-69 and isn’t too
difference with Poplar2025.
The leaf colour of Populus deltoides CV.“zhonghong” is inimitable, which obviously
changes along with reasons and display extremely steady. The all leaves and newly tender
leaves are rose from sprouting to early summer. Henceforth, the tender leaves and branchs are
vividly mauve till the middle ten days of October, but mature leaves on middle and lower stem
change red-green to green. The whole blade turns into apricot pink gradually after mid-October,
until falling leaves.
The stem of Populus deltoides CV.“zhonghong” , as a high arbor, is tall and straight, which
grow rapidly and the crown is fleshy. At the same time, it is a good ornamental, breed easily

and spread widely. Furthermore ， it more resists Poplar borer, aphid, acarus and rust than
Poplar2025. So it has filled in the blanks of the colored leaf varieties of trees and has a
enormous development potentiality.
Populus deltoides CV.“zhonghong” , as male tree, doesn’t pollute environment for fling
garrulous . Accordingly, it is applied to city virescence, fast-growing and high-yield plantation,
which is a rare varieties afforested in the passway , the joint department, urban and rural areas
or big environmental. In other words, it has enormous economic, society and ecological benefit.
Grafting and cutting are primary reproductive mode of Populus deltoides CV.“zhonghong” .

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International poplar symposium Ⅳ Nanjing, China. 2006

The survival rate is highest with maternal variety, and the growth is the most rapid.
In a word, Populus deltoides CV.“zhonghong” ,as colored leaf and growing varieties of
trees rapidly, has enormous development potentiality and broad market prospects, which is a
new variety demanding urgently to be developed.

POPULUS

X

GENEROSA

HYBRIDIZATION
76

IN

THE

PACIFIC


International poplar symposium Ⅳ Nanjing, China. 2006

NORTHWEST: A CASE STUDY OF A STRATEGIC NON-RECURRENT
IMPROVEMENT PROGRAM
Stanton, Brian J. and Shuren, Richard, A.
GreenWood Resources, Portland, Oregon, USA,

Genetic gains in poplar productivity in the Pacific Northwest over the last 25 years have
been brought about largely through an empirical approach to tree breeding. This has taken the
form of non-recurrent F1 hybridization involving the indigenous P. trichocarpa and P. deltoides
from eastern North America. Non-recurrent hybridization was chosen as the preferred strategy
as regionally adapted, elite varieties were very limited in number at the time commercial
plantations were first established. This situation created an imperative to rapidly produce a
sizable pool of new selections equal in productivity to the best commercial standards and
recruited from a diversity of pedigrees that collectively would minimize the risk of plantation
failure posed by evolving pest and unforeseen weather events realized through the continuous
deployment of a restricted number of hybrid varieties. Although it was recognized that this
strategy would not improve the mean performance of the F1 generation through the
accumulation of positive alleles via recurrent breeding of the constitutive parental species, the
belief was that the overall performance of the operational clone pool could be improved over
time through substitutions for the least productive standard clones using extreme genotypes
selected from test populations bred from parental stock of unknown breeding value.
The non-recurrent program was designed to annually recover superior genotypes selected
for Melampsora leaf rust resistance and stem volume from 12 F1 populations created from
1990-2001. Each population was evaluated as a discrete set using a multiple-stage process to

identify individuals capable of meeting production yield targets. Rust resistance was rapidly
developed by phenotypic selection at the outset of the process using two selection thresholds in
seedling nurseries. Population variation in the underlying determinants of resistance (e. g.
number of uredinia, length of latent period, sporulation rate) was reduced from 0.84 threshold
units (t.u.) at the seedling stage to 0.56 t.u. at the first stage of clonal evaluation when averaged
over the 12 years. At the same time, the mean rust liability of the test populations increased on
average from –0.10 t.u. in unselected seedling populations to 0.44 t.u. in selected clonal
populations. Following truncation for rust resistance, populations were subjected to two cycles
of clonal evaluation for several components of individual stem weight to identify selections for
rotation-age yield tests. Those entering this final test stage exceeded first and second stage
clone test means for stem diameter by 1.58 and 1.23 phenotypic standard deviations on average,
respectively. To date, the merchantable tonnage of those top selections that completed a full
eight-year rotation of yield testing have matched the productivity of the top standard
operational varieties (96 dry MT/ha) with individual clones producing up to 105 MT/ha.
Additional gains in plantation yields have been possible by exploiting clone-by-environment
interactions.
The continuity of the non-recurrent hybridization program has benefited from its

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International poplar symposium Ⅳ Nanjing, China. 2006

promotion as a propagation system - as opposed to a genetic improvement system per se - that
was considered vital to sustained commercial operations to the extent that it ensured the
ongoing availability of planting stock as clones were routinely taken out of service due to
abiotic and biotic agents. Additional factors that contributed to the success of the program have
included the following.
1.Reliable design parameters that guided the recreation of F1 populations from which extreme
genotypes projected to meet production targets were consistently recovered.

2.An abundance of parental breeders of both species with which the F 1 generation was
reproduced with minimal re-sampling resulting in widespread production of novel pedigrees.
3.Selection criterion of high clonal repeatability (i.e. rust resistance) that effectively narrowed
test populations to manageable number of clones allowing for more rigorous experimentation of
traits of lower repeatability (i.e. yield).

PROPAGATING HYBRID ASPEN (Populus tremula x P. tremuloides)
FROM ROOT CUTTINGS
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International poplar symposium Ⅳ Nanjing, China. 2006

Stenvall, N., Haapala, T. and Pulkkinen, P.
Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland, /
Fax: +358 10 211 2204, ,

Clonal variation is the most important fact in propagation of hybrid aspen (Populus
tremula L. x P. tremuloides Michx.): all factors related to regeneration efficiency are strongly
genetically controlled. We have investigated for a several years the clonal propagation of hybrid
aspen from root cuttings.
The root system structure of clones defines the amount of root cuttings and affects their
ability to sprout and root. It is very important for mass production of plants to find clones that
produce large amount of root cuttings, but even more significant in question of production costs
is that the produced cuttings have high ability to sprout.
Obviously, the two-year-old stock plants can produce far more cuttings than the one-yearolds. There was no difference in regeneration capacity of one and two-year-old stock plants
roots. Practically, root cuttings taken from all parts of the root system of hybrid aspen are
capable to produce new shoots and roots. The diameter of cutting did not affect the sprouting
efficiency, but it had strong impact to rooting of cuttings. The fact that efficiently sprouted
clones also rooted best facilitates the selection of clones.

The increased soil temperature is beneficial for root cutting propagation of aspen. The soil
temperature of 30ºC was best for sprouting and rooting of the cuttings and also hastened the
rate of sprouting. Light did not affect to the sprouting of root cuttings, but did have a negative
effect on their rooting efficiency. With the treatments used it is possible to decrease the clonal
differences in sprouting and rooting of aspen root cuttings, but clonal selection still remains a
very important aspect of the propagation procedure particularly when cuttings are used for
economically successful mass propagation.

Review of Genetic Improvement on Broadleaf Tree Species in
Shandong Province
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International poplar symposium Ⅳ Nanjing, China. 2006

QIN Guanghua,∗ JIANG Yuezhong, MA Ling
Shandong Academy of Forestry, Jinan 250014, P. R. China

∗

E-mail:

The paper presents a brief review of genetic improvement on broadleaf tree species in
Shandong province in the past. It summarizes the advancement in tree breeding on main
broadleaf tree species in the province. Weakness in the previous work is also identified and
discussed. It ends with some recommendations for the future tree breeding in the province.
Key words: broadleaf trees, genetic improvement, tree breeding, Shandong

Review of the poplar clonal testing program in Chile: 2002-2006
Francisco Zamudio

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International poplar symposium Ⅳ Nanjing, China. 2006

Poplar Research Center. Universidad de Talca. Chile.

Between years 1999 and 2002, the Poplar Research Center (PRC), Universidad de Talca,
introduced to Chile more than two thousand inter-specific poplar hybrids, from the USA and
Europe. Each one of the three set of hybrids imported was carefully established in a rigorous
one-year quarantine. After released from quarantine, hybrids were transferred to an
experimental propagation nursery inside the main campus. Between years 2002 and 2005, the
PRC began establishing hybrids in a clonal testing network mainly formed by nursery type of
trials (one cutting of many hybrids per each one of two blocks). Today, the network includes
eight testing sites and eleven tests spread across 115,723 km 2 of the center – south regions of
the country. Growth in height and diameter and tolerance or resistance to plagues and diseases
(triggered by local environmental stresses) were yearly measured in each trial. Data analyses
based on linear mixed model theory were conducted within each individual test. Across-site
analyses were also carried out when data structure allowed. Clonal rankings were generated in
terms of growth rate and adaptability to pests and diseases for each testing area, and based on
the best linear unbiased prediction (BLUP) methodology. Hybrids located in the upper 5 to 10
% part of the rankings were selected at the end of 2005 and will be established in several
screening tests (single cutting-tree-plot in 10 blocks per trial) within the testing network, during
winter of 2006. The new set of trials will initiate a second stage of clonal selection whose main
objective will be to select hybrids with a combination of growth and juvenile wood that is
suitable for the Chilean wood processing industry that produces high quality end products. The
main impacts of our current research are expected to be: (1) a significant increment in poplar
wood of high quality, suitable for the industry of wood transformation; (2) a significant
reduction in the risk investment in managing poplar stands planted with our selected hybrids;

(3) an improvement in the economic value of land with no present use, or undervalued; and (4)
an increment in our understanding of wood formation in selected hybrid poplars (with known
pedigree). Starting 2006, the PRC will also initiate other research lines oriented to select
hybrids suitable for resolving environmentally related problems in Chile, such as the use of
hybrids for: (1) carbon sequestration; (2) phytoremediation; and (3) energy generation.

SELECTION OF CHINESE WILLOW (SALIX MATSUDANA) AND
WHITE WILLOW (S. ALBA) CLONES AND THEIR HYBRIDS
SUITABLE FOR BIOMASS PRODUCTION
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International poplar symposium Ⅳ Nanjing, China. 2006

Kajba, D. (1), S. Bogdan (1), I. Katičić (1)
(1) University of Zagreb, Faculty of Forestry, Department of Forest Genetics, Dendrology and Botany.
Fax. +38512352505

In 2002, an experimental culture of short rotation crops for biomass production was
established on an abandoned farmland. It includes 25 clones of arborescent willows grown from
open pollinated chinese willow (Salix matsudana), the hybrids between chinese and white
willow (S. matsudana x S. alba) x unknown, the back crosses of S. matsudana x S. alba with
chinese willow, the hybrids between chinese and white willow (S. matsudana x S.alba),
together with a few white willow clones (Salix alba), and one trispecies hybrid (Salix alba x S.
fragilis x S. caprea). At the age 2/3 (2-year-old shoots and 3-year-old stump) first
measurements of the given culture were conducted. Measures were taken for all the plants at
their breast height (1.30 m from the ground), and fresh biomass of the wooden shoots was
measured on a 10% sample of each clone. Samples of 1kg of biomass of all the clones were
oven-dried at 105 ˚C to constant weight. That way, data were obtained on the moisture content
in wood biomass. Data reporting on fresh biomass of the observed clones were reduced

according to the respective moisture content, enabling biomass estimation of a dry sample.
Nonlinear regression analysis run for dry biomass and diameter at breast height of the sampled
plants shows strong relationship between those two traits. By using the obtained regresssion
models together with the previously measured diameters at breast height, estimation was made
of dry biomass of each individual plant in the experimental culture. Biomass production per
hectare was estimated according to dry biomass of a mean ramet, planting density and survival
rate at the observed age.
Average dry biomass output reached 5.6 t/ha, however, a significant variation between the
tested clones is clearly visible. The largest production was achieved by the clones ‘V 580’ (10.5
t/ha), ‘V 578’ (9.9 t/ha), and ‘V 575’ (8.8 t/ha), selected in the openl pollinated family of the
clone S. matsudana ‘Tsinan’, as well as by the clone ‘V 572’ (9.9 t/ha) grown from open
pollination of the clone S. matsudana × S. alba ‘Tangoio’.
The white willow clones, as well as the clones grown by means of back crossing between
chinese willow and the hybrids of chinese and white willow, proved to yield below the average
output. The poorest biomass production was recorded for the trispecies hybrid Salix alba × S.
fragilis × S. caprea ‘V 221’ which was 1.7 t/ha. Among the hybrid clones S. matsudana × S.
alba, only the clone ‘Tangoio’ yielded the largest ouput with 8.6 t/ha.
Average survival of the tested clones was 86 %, ranging from 53% (clone ‘V 221’) to
100% (clones ‘V 580’ i ‘V 576’).
The obtained results have shown high production of dry biomass by the arborescent
willow clones grown from open pollinated maternal trees of the chinese willow (S. matsudana).
The arborescent willow clones were reported to have a significant potential for biomass
production in short rotations and are to be recognized as useful form of providing energy
supplies in similar habitats.

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International poplar symposium Ⅳ Nanjing, China. 2006

Selection of poplar and willow clones based on growth performance
for 9 years at a metropolitan waste landfill site
Koo, Y. B.*, K. S. Woo, J. K. Yeo , Y. S. Kim

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