Ministry of Agriculture & Rural Development Collaboration for Agriculture and Rural Development

Strengthening Capacity in Forest Tree Seed Technologies Serving
Research and Development Activities and ex-situ Conservation
(No. 058/04VIE)

GENETIC IMPROVEMENT PLAN FOR
EUCALYPTS IN VIETNAM by Khongsak Pinyopusarerk
1
, Le Dinh Kha
2
and Chris Harwood 1
Ensis Genetics, PO Box E4008, Kingston,
ACT 2604, Australia

2.2 Development of Eucalypt Hybrids 9
2.3 Open Pollinated Progeny Trials Developed into Seedling Seed Orchards 10
2.4 The Need for a Genetic Improvement Strategy and Plan 10
3 Basic Elements of Planning Tree Improvement 11
3.1 Need for a Well Defined Strategy and Plan 11
3.2 Clear Objectives 11
3.4 Selection and Mating 12
3.5 Personnel and Funding 13
3.6 Hybrid breeding 13
4. Determinants of a Breeding Strategy 15
4.1 Breeding Objective 15
4.2 Economic Weights 15
4.3 Deployment Objective 15
4.4 Selection Criteria and Traits for Selection 16
4.5 Genetic Resources 16
5 Breeding Strategy 20
5.1 Outline of Breeding Strategy 20
5.2 Expected Genetic Gains 21
5.3 Breeding Population 22
5.3.1 Structure of the Main Population 22
5.3.2 Structure of the Elite Population 22
6 Outlines of Improvement Plan 23
6.1 Eucalyptus urophylla 23
6.1.1 Main breeding population and seedling seed orchard 23
6.1.2 Elite population and clone bank/clonal seed orchard 23
6.1.3 Selection of candidate trees for the second generation 28
6.1.4 Conversion of trials to seed orchards 29
6.2 Eucalyptus pellita 29
6.2.1 Main breeding population and seedling seed orchard (optional) 30
6.2.2 Elite population and clone bank/clonal seed orchard 30

superior seed suitable for the different ecological zones in Vietnam. The GoV is committed
to improving the amounts and qualities of tree seed produced from its own seed orchards,
which is a more sustainable strategy than depending on imported seed. Exotic species such as
acacias and eucalypts are important species included in the planting programs.

In order to enhance the productivity of the plantations in Vietnam, genetic improvement
programs have been carried out for many tree species mainly by the Research Centre for
Forest Tree Improvement of the Forest Science Institute of Vietnam. However, these works
have been conducted without a written plan that follows a clearly defined genetic
improvement strategy. As part of AusAID-supported CARD project (No. 058/04VIE)
“Strengthening Capacity in Forest Tree Seed Technologies Serving Research and
Development Activities and ex-situ Conservation” a genetic improvement plan has been
developed focusing on priority Eucalyptus species. A separate CARD project (No.
032/05VIE) “Sustainable and profitable development of acacia plantations for sawlog
production in Vietnam” will soon develop a genetic improvement plan for acacias. It should
also be stressed that the approaches discussed in this breeding strategy are applicable for
most tree species.

Breeding populations of five Eucalyptus species (E. camaldulensis, E. grandis, E. pellita, E.
tereticornis and E. urophylla) already set up by the Research Centre for Forest Tree
Improvement provide the basis for genetic improvement framework being addressed by this
improvement plan. However, greater effort and input are put into E. urophylla as the highest
priority Eucalyptus species for pure and interspecific hybrid breeding. Other species have
been managed less extensively with an aim to use them as pollen sources for interspecific
hybridisation.

The proposed breeding strategy is based on a structured breeding population that is divided
into two levels based on genetic quality. That is the breeding population is subdivided into
two parts, a ‘Main (large) Population’ and an ‘Elite (small) Population’. The populations
have several distinct functions in the breeding program, and a large part of the breeding

some period of operation. This genetic improvement plan is no exception and should be
subject to an independent review after 2 years into the program.

5
1 Introduction and Background

Eucalypts are one of the most important groups of plantation species for the supply of
industrial raw materials in Vietnam. Their wood is used for pulp and paper, particleboard,
construction and furniture. There are substantial block plantations of eucalypts in many parts
of Vietnam. They are widely planted along canal banks in the Mekong Delta, and along
dams, rice paddy boundaries and roadsides and as wind breaks in the Red River Delta. They
are also widely planted in many places throughout the country as scattered trees. Moreover,
eucalypts provide much of the fuel wood for most of rural areas of Vietnam. Together with
acacias, eucalypts have significantly contributed to the improvement of income and living
standards of rural people in lowland areas, particularly in central and central-northern
Vietnam. The area of eucalypt plantations Vietnam at the end of 2001 was estimated as 348
000 ha (Le Dinh Kha et al. 2003a). The current planted area is believed to be around 500,000
ha. This figure does not include millions of row plantings and scattered trees equivalent to
50,000 ha in routine plantation form.

Eucalypts have been introduced into Vietnam since 1930. Eucalyptus camaldulensis and E.
robusta were the first Eucalyptus species introduced into Vietnam in 1930 by the French.
More species were introduced during 1950-1958 in Da Lat (central highlands), and among
these E. microcorys was found to be very promising. In 1960 E. exserta was introduced and
became an important species for re-greening bare land and denuded hills. Up to 50,000 ha of
E. exserta plantations were planted during the 1960s. However, the popularity of E. exserta
has since declined because of its slower growth rate than other species.

It was not until the 1980s that systematic species and provenance trials were established at
different ecological zones of Vietnam. However, lack of comprehensive representations of


v (%)
x

v (%)
23645 E. urophylla Mt Lembata, Indonesia 11.4 19.3 13.2 15.9
23081 Mt Egon Ind. 9.3 21.8 10.7 9.1
23042 Mt Lewotobi Ind. 9.0 23.2 10.5 18.3
Mean 9.9 21.4 11.5 14.4
14236 E. cloeziana Herberton Qld 10.5 20.1 12.7 17.9
12602 Helenvale Qld 10.3 15.2 11.6 13.3
17008 Woondum Qld 10.3 23.2 11.6 14.3
14422 Cardwell Qld 10.3 20.5 11.3 20.4
12205 Maitland Qld 10.1 17.7 11.0 15.2
12202 Paluma Qld 10.0 17.2 11.0 11.6
13543 Monto Qld 9.6 21.9 10.9 15.3
12207 Bakerville Qld 9.6 20.6 10.8 10.6
14427 Blackdown Qld 9.5 17.7 10.7 9.0
Mean 10.0 19.3 11.3 14.2
15255 E. pellita Kuranda Qld 10.2 18.6 11.3 12.6
14211 Helenvale Qld 10.2 16.8 11.1 14.9
16122 Kiriwo PNG 10.1 20.6 11.0 17.4
13998 Coen Qld 9.7 17.6 10.9 12.6
16120 Keru PNG 8.9 25.2 10.2 17.0
13826 Bloomfield Qld 8.4 22.1 9.8 17.2
Mean 10.1 18.6 11.1 14.3
13661 E. tereticornis Mt Molloy Qld 8.9 20.1 10.2 17.6
13660 Helenvale Qld 8.8 21.4 10.2 18.6
13666 Mt Garnet Qld 8.4 19.7 10.0 17.7
Mean 8.7 20.4 10.1 18.0

Jackey, Qld; E. camaldulensis Emu Creek Petford, Qld; E. tereticornis Mt Garnet, Qld; E.
grandis Mt Lewis and Tinaroo, Qld. All E. pellita provenances grew slower than overall trial
mean. The high altitude of 1500 m appeared to be too high for many Eucalyptus species such
as E. brassiana, E. camaldulensis,
E. pellita and E. tereticornis.

No further detailed information from these 1992 trials was available except a brief reference
in Le Dinh Kha et al (2003a) that some 11-year-old trees of Da Lat land races of E. saligna
and E. microcorys were growing well at Lang Hanh, mean height 25.1 and 22.5 m
respectively.

Based on the results of past species and provenance trials, many species are considered
promising for planting in different regions of Vietnam:

Lowlands, central to southern provinces: E. brassiana, E. camaldulensis, E. cloeziana, E.
exserta, E. pellita, E. tereticornis, E. urophylla

Lowlands, northern provinces: E. exserta, E. pellita, E. urophylla (on deeper soils (canal
banks, roadsides etc) E. camaldulensis is an excellent performer and widely planted in the
north, although it is no good on the shallow hillside soils. I don’t know that there is much
evidence that E. pellita is good in the north (it may be). You probably need a paragraph
describing the different types of planting sites available – small planting areas on flat land
with deep soil, and much larger areas (bare hill type site) of sloping land with generally rocky
shallow soil especially in north and central-north. In the south and parts of the central
highlands there are larger areas of better soil and reasonably level ground although these are
mostly being planted to acacia hybrid now. The species rankings and performance of hybrids
change according to these soil types.

Central highlands: E. grandis, E. microcorys, E. saligna,E. urophylla and E. pellita can also
be planted up to altitudes of around 900 m asl in the Central Highlands.

Improvement (RCFTI) is the leading government agency conducting genetic improvement of
eucalypts in Vietnam. A great deal of this work is in cooperation with FSIV regional centres
such as those in central and southern Vietnam. Other agencies conducting or involving in tree
improvement work include Phu Tho Forestry Research Centre and some of the Provincial
forest departments. The work program is described in the following sections.

2.1 Candidate Plus Tree Selection and Clonal Testing

Prior to mid 1990s, the focus of genetic improvement was on selection of locally grown
superior trees of E. camaldulensis and E. urophylla, followed by clonal testing for high
productivity and adaptability. Some highly productive eucalypt clones of E. urophylla and its
interspecific hybrids were also imported for planting, e.g. from China.

In 1993, a clonal trial testing 38 clones of E. camaldulensis selected from a 4-year-old
plantation was established at Cam Qui, Ha Tay province. Diameter and height of all selected
trees exceeded the plantation mean by more than 1.5 standard deviations. Eight clones were
found to perform better than commercial seed of E. camaldulensis (C), E. exserta (E), E.
urophylla (U) and a natural hybrid E. exserta x E. camaldulensis (EC). Results at 7 years
showed that 26 clones grew faster than E. camaldulensis control and 12 were poorer. The
stem volumes of the two fastest clones C22 and C7 were two times greater than the E.
urophylla seedling control and three times greater than the E. camaldulensis clones. The trial
provided a good lesson to local forest research institutes the essential need to field-test clonal
selections.

Candidate plus trees of E. urophylla were also clonally tested. The Forestry Research Centre
in Phu Tho has selected many superior individuals of E. urophylla from plantations and
provenance trials and tested them in clone trials. Some of these are now listed as commercial
clones: PN
2
, PN


9
and storage and controlled pollination techniques were carried out for all three species. By
controlled pollination, reciprocal hybridisation between the three species has been conducted
and more than 70 inter- and intraspecific hybrid combinations have been made. Some of the
interspecific hybrid families created by RCFTI have out-performed their parental species in
terms of volume growth by 100-300%. Results from this work were reported in Le Dinh Kha
et al. (2003a).

In general, the hybrid combination UC grows well on the deep soils of the Red River delta
and seasonally waterlogged, acid sulphate soils in Kien Giang province. Hybrid combinations
UE and EU are usually fast-growing on hill sites. Intraspecific crosses within E. urophylla
also perform well in these environments. Hybrid combinations EC and CE are the slowest
among the hybrid combination created. Their growth is only slightly better than the open-
pollinated offspring of their parent trees. The performance of individual hybrid and pure-
species families can be classified into the following groups (suffixes refer to parent tree
numbers):

(i) Fast growing hybrid combinations for hill sites, deep and fertile soils in Red River
delta and acid sulphate soils in Kien Giang (Mekong Delta): U
15
C
4
, U
29
E
1
, U
29
E

E
4
U
29
, U
29
U
26
and U
29
U
24
.

2.3 Open Pollinated Progeny Trials Developed into Seedling Seed
Orchards

From mid 1990s to early 2000s, with funding support from Vietnam government, ACIAR
and AusAID, and cooperation of CSIRO scientists, RCFTI established open pollinated
progeny trials integrated with seedling seed orchards of key species including E.
camaldulensis, E. grandis, E. pellita, E. tereticornis and E. urophylla. These plantings were
initially established as provenance-progeny trials, and are assessed and selectively thinned as
they develop. They are very important not only to supply seed, but also for selecting the most
promising provenances, families and superior individuals for further genetic improvement.
Together, these plantings now provide most of the breeding populations for genetic
improvement programs in Vietnam. Details of these plantings are discussed in Section 4.5.

2.4 The Need for a Genetic Improvement Strategy and Plan

To date the RCFTI has done an excellent job of conducting genetic improvement of key

overviews, or philosophy of the management of genetic improvement of a tree species used
in plantations. Its essential elements are:

(a) population improvement by a combination of a particular type of selection and a
particular type of mating, starting with a well adapted broad genetic base; and

(b) an efficient system for mass propagation of outstanding selected individuals either as
seed or cuttings.

Breeding plan – having decided which Breeding Strategy (particular combination of selection
and mating) will provide the greatest gain per generation at an acceptable cost for a particular
plantation program, the tree breeder can write a detailed Breeding Plan to implement the
Strategy. Typically the plan includes a set of objectives and a flow chart of what is to be done
each month or year for several years ahead and is subject to regular revision, every 2-5 years
(Eldridge et al. 1993).

3.2 Clear Objectives

Tree breeding projects should have a clear set of objectives defining the improvements
required and identifying the traits to select. These traits and the economic weights given to
the different traits for improvement should aim to improve the economic performance
(profitability) of the tree growing and processing industries (Greaves et al. 1997).

3.3 Hierarchy of Four Populations in a Breeding Strategy

As an ongoing recurrent process, a breeding strategy accumulates benefits over successive
generations through a cycle of testing, selection and mating (Figure 1). Every effective
breeding strategy for an individual tree species involves the maintenance of a hierarchy of
three major types of population which can continue to meet the demand for genetically
improved planting stock for a fourth population, the commercial plantations. These four

select trees
BASE
progeny
tests
seed
orchards/
clone banks
plantations
selection
mass
propagation
mating

In some programs two other types of populations are also employed. One is an ‘infusion
population’ which comprises additional material from the base population or elsewhere. It is
brought into the breeding population in the second or later cycles of breeding to maintain or
increase genetic diversity and provide additional superior genetic material (Harwood and
Mazanec 2001). The other is a ‘nucleus population’ or ‘elite population’, which is a small
subpopulation of the breeding population. Elite populations typically comprise less than 50
genotypes which are the focus of the most intensive breeding (Erikson and Ekberg 2001). In
the shorter term, larger gains can be provided by the smaller elite population. Gene
conservation and long-term gains are provided by the larger or main subpopulation of the
breeding population.

3.4 Selection and Mating

Selection and mating are key activities in breeding. They accumulate genes which influence
yield and adaptation, increasing over successive generations the frequency of superior trees.
Every successful breeding strategy, therefore, requires efficient methods of selecting superior
material including the progeny tests in which the selection is carried out, appropriate

known from work in Vietnam and elsewhere that good interspecific hybrid combinations can
be made among the following species of the subgenus Symphyomyrtus, all of which are
established in Vietnam: E. camaldulensis, E. exserta, E. grandis, E. pellita, E. saligna, E.
tereticornis and E. urophylla. None of these species can be crossed with Corymbia
citriodora, which is in a different subgenus.

Most successful hybrid clones are derived from crosses between pure-species parents, but
this is not always the case. Outstanding advanced-generation hybrid clones have been
produced in southern Brazil by crossing among superior hybrid individuals (T.F. Assis, pers.
comm. 2001), but inviability is frequently encountered.

The degree to which the breeding value
1
of an individual for pure species breeding correlates
with its hybrid breeding value is not yet fully understood. However, hybrid breeders
generally select superior pure-species individuals for hybrid breeding, and this approach is
sensible in the absence of detailed information obtainable from complex breeding schemes
such as reciprocal recurrent selection.

In general, interspecific eucalypt hybrids must be mass-propagated for plantations by
vegetative propagation of selected hybrid clones. This is because open-pollinated seed
collected from F
1
hybrid individuals displays segregation or hybrid breakdown, with high
variability and poor vigour F
2
progeny, making them unsuitable for plantations. It would be 1

enterprise, or the grower-processer enterprise for vertically integrated producers who use the
wood products produced in the plantations. To put it another way, genetically improved
planting stock enables production of high-value products, fetching a high price from users, at
a lower cost, through faster growth and improved product quality. In Vietnam, the main
wood products from eucalypt plantations are pulpwood, small to medium sawlogs, and poles
for scaffolding and informal construction. Small-diameter log ends, branches and offcuts are
usually used for fuelwood.
4.2 Economic Weights
“Economic weights are defined as the additional profit that may be expected from a one unit
increase in a trait X (say a cm
2
increase in sectional area of stem) relative to that from a one
unit increase in trait Y (say a 1 kg m
-3
increase in wood density)” (Cotterill and Dean 1990).

There are several approaches to determining appropriate economic weights (Cotterill and
Dean 1990). They can be derived from detailed financial analyses of the processing
industries, but this can become quite a major undertaking. Alternatively, production functions
can be used to describe the economic relationship between biological traits, as factors of
production in the case of a breeding objective and final profit of an integrated plantation and
wood processing industry (Greaves et al. 1997). Several published studies provide instructive
examples (see Ponzoni 1986, Fonseca et al.1995, and Greaves et al. 1997).
There is a need to undertake detailed analyses and studies necessary to derive the appropriate
economic weights for use in the eucalypt breeding program in the near future. These
economic weights can then be used to identify the value of each trait to the breeding program
(which can be defined as the relative improvement toward the breeding objective for a given
selection intensity when selecting for each trait individually (Greaves et al. 1997). It is no use
aiming to improve traits that are of no value! The main objective traits for kraft pulpwood
are well known – they are wood volume at rotation age, wood density and percentage pulp

vii) thin branches that shed easily (more important for solid-wood products such as
sawlogs)

It should be noted that when a large number of traits is selected simultaneously, genetic gain
in individual traits generally tends to diminish as the number of traits under selection
increases. In practice, therefore, breeders must try to minimise the number of traits under
selection.

The most important traits under selection for increased pulpwood production are volume and
basic density (Borralho et al. 1993). At present for most growers, valuable wood is that
which has high density as wood is sold on a weight basis (wood is often still sold on a
stacked volume basis in the field, but by green weight at the pulp or chipmill). Thus the target
for the growers is big, healthy, straight trees with higher density wood. Ideally, an average
wood basic density of between 500 and 550 kg m
-3
is considered desirable for pulpwood
plantations. Older trees of some high-density species (E. camaldulensis and E. tereticornis)
will actually be too dense for pulping, the upper end of the optimum range is 600 kg m
-3
.

Efficiency of selection may be improved by utilising a multi-trait selection index. Smith-
Hazel indices are often used and incorporate information on heritabilities, genetic
correlations and phenotypic correlations, but the calculations are complex (Cotterill and Dean
1990). If the key traits in the index are not strongly correlated, then simple indices such as the
primary index can work just as well for selection in first-generation breeding populations and
are far easier to calculate. At present, it is relatively easy to predict multivariate breeding
values and do multi-trait selection using multivariate ASReml. However, this is mainly
relevant to pure-species breeding, not hybrid breeding and deployment which will probably
be more important in the long run in Vietnam.

Phu Tho
Ba Vi Ha
Tay
17564 Mandiri, Flores 08 15 122 58 410 11 9
17565 Lewotobi, Flores 08 32 122 48 375 35 33
17567 Egon, Flores 08 38 122 27 450 36 36
17831 N of Ilwaki, Wetar 07 52 126 27 515 13 18
17836 SW of Uhak, NE Wetar 07 39 126 29 350 25 22
17840 Wai Kui, central Alor 08 14 124 44 540 5 5
17841 Piritumas, W Alor 08 19 124 31 355 8 9
17842 Dalaki Mtn, SE Pantar 08 31 124 05 440 5 5
17843 Baubillatung, W Pantar 08 20 124 02 285 6 7
Total 144 144
Table 2. Seedlots of E. urophylla from Indonesia and number of families represented in the
main breeding population in VietnamTable 3.
Seedlots of E. pellita and number of families represented in the main breeding
CSIRO
Seedlot No.
Provenance location
State/
country
Latitude
(S)
Longtitude
(E)
Altitude
(m)

13398 East of Kupiano PNG 10 04 148 15 25 17 10 10
13399 Oro Bay to Emo PNG 08 57 148 28 200 11 8 8
13418 Sirinumu Sogeri Plateau PNG 09 30 147 26 580 20 17 13
13442 N of Mareeba Qld 16 55 145 25 380 1 1 1
13446 N of Cardwell Qld 18 16 146 00 40 1
13661 Mount Molloy Qld 16 41 145 15 366 1 1 1
13995 SEof Dubar Qld 16 15 143 00 70 1 1 1
14115 S of Helenvale Qld 15 46 145 14 120 1 1
14212 5-12km S Helenvale Qld 15 45 145 15 500 2
14444 Helenvale Qld 15 40 145 14 180 1 1 1
14846 S of Cardwell Qld 18 28 146 06 10 1 1 1
14856 W of Mareeba Qld 16 46 145 15 380 1 1 1
14863 Helenvale Qld 15 48 145 13 160 1 1 1
15369 SSE of Helenvale Qld 15 48 145 13 160 1 1 1
15370 N of Mareeba Qld 16 46 145 15 380 1 1 1
16347 Mitchell River Qld 16 47 145 22 400 1 1 1
16348 Mt Granet Spring Ck Qld 17 41 145 05 640 1
16349 Atherton Wongabel Qld 17 19 145 28 780 1 1 1
16532 SE of Irvine Bank Qld 17 27 145 13 750 3 1 1
16538 Collins Weir Qld 17 14 145 18 550 3
16541 W-NW of Dimulah Qld 17 09 145 06 450 1
16542 Mount Molloy Qld 16 39 145 19 370 2
16543 Luster Creek Qld 16 39 145 14 390 1
16545 Holmes Creek Qld 16 32 145 07 370 3 1 1
16554 SW of Mount Garnet Qld 18 24 144 45 890 1 1
16558 Oaky Ck Spring Mount Qld 17 11 145 20 540 3 3 3
16645 Mitchell R Oaky CK Qld 16 46 145 15 380 1
16647 Holmes Ck Mt Carbine Qld 16 32 145 07 330 1
18167 Maher St Atherton Qld 17 16 145 29 780 1
18589 S Helenvale Qld 15 50 145 14 200 1 1 1

(m)
No. of
families
18694 Woondum Qld 26 18 152 49 80 5
18700 Connondale Qld 26 40 152 36 560 5
18769 Piccaninnt Ck, Windsor Qld 16 13 144 58 1160 10
19307 Finch Hatton Gorge Qld 21 04 148 37 200 5
19966 Lake Morris, Copperlode Qld 16 59 145 40 450 6
19967 Mt Spec SF Paluma Qld 18 56 146 07 850 9
19968 Tinaroo Creek Road Qld 17 05 145 34 1050 10
19969 Davies Ck, Mareeba Qld 17 03 145 37 725 9
20555 Koorlong Plantation VIC 34 19 142 04 55 5
20668 Copperlode Qld 16 58 145 40 425 13
Da Lat land race Vietnam 3
Total 80
main breeding population planted at Lang Hang, Lam Dong, Vietnam.
Qld = Queensland, Vic = VictoriaTable 6. Seedlots of E. camaldulensis from Australia and number of families represented in the
CSIRO
Seedlot No.
Provenance location State
Latitude
(S)
Longitude
(E)
Altitude
(m)
No. of

functions in the breeding program, and a large part of the breeding strategy each generation
deals with the plan that specifies the selection, breeding and management of these two
components of the breeding population.

In Vietnam, interspecific hybridisation is receiving increasing interest. The ‘Elite Population’
is the source of genetic material used for interspecific hybrid crossing, in addition to it being
one of the sources of pure-species clones for operational deployment. Therefore, the strategy
needs to place maximum emphasis on this population to ensure maximum genetic progress.
The ‘Main Population’ provides a broad genetic base that is managed less intensively to
provide for gene conservation and long-term, sustained genetic progress, by providing new
selection to the ‘Elite Population’ each generation. A diagrammatic form of the strategy is
presented in Figure 2.

Therefore, the strategy for eucalypt improvement program in Vietnam necessitates open-
pollinated management of the Main Population each generation. This is a simple, low cost
option that

(i) obviates the need for any controlled pollination among selections,
(ii) allows rapid turnover of generations, and
(iii) provides for substantial genetic progress.

For the Main Population, there is only a single type of genetic test (i.e. open-pollinated
progeny test) each generation. The families and individual trees within families are ranked
using the test data, and selections are made in these open-pollinated progeny tests both to
move up to enrich the gene pool of the Elite Population and to regenerate the next
generation’s Main Population. Thus, the overall strategy in the Main Population can be
defined as recurrent selection for general combining ability with open pollination in a
breeding population keeping family identity (Namgoong et al. 1989, Eldridge et al. 1993).

A greater emphasis is placed on the breeding, testing and selection of the Elite Population

eneration
Collect seed
for
p
lantation
Controlled crossing
(
intra & inters
p
ecific
)
Progeny trials
Clone trials
Plantation establishment
Fi
g
ure 2.
A general schematic diagram representing the basic breeding strategy.
Next gen breeding
population

5.2 Expected Genetic Gains
A significant proportion of the gains to be achieved in the first cycle is generally due to
releases from ‘neighbourhood inbreeding’. Natural stand eucalypt seed has a degree of
inbreeding due to neighbourhood inbreeding effects (Eldridge et al. 1993). Experience from
other eucalypt breeding programs indicates that usable volume gains of up to 20% per
generation can be anticipated from seed produced by the seedling seed orchards, over and
above those from provenance selection, with substantial improvement in form traits as well
(Meskimen 1983). Gains from deployment of tested clones are expected to be greater than
those from improved seed (Shelbourne 1991). Similarly, gains from tested interspecific

broaden the genetic base of the smaller Elite Population;

(iv) to provide the best individuals of the best families to establish clonal seed orchards
if that is required; and

(v) to provide a broad genetic base for gene conservation and flexibility in case of
unexpected changes in product goals or emergence of challenges such as new pests
and diseases or change in climate

RCFTI’s main populations of Eucalyptus species (see Tables 2-6) were established as open-
pollinated progeny trials using latinised row-column designs. Each trial was established using
6 -10 replicates of 4-trees plots planted at 4m x 1.5m or 2m x 3m spacing with. These designs
are still considered appropriate for any main breeding populations to be established in future.

The main breeding population of most species was established on two to three locations to
provide against catastrophic loss, increase the precision of the parental rankings, and increase
the intensity of within-family selection.
5.3.2 Structure of the Elite Population
For each of E. urophylla, E. camaldulensis, E. pellita ? The Elite Population each generation
will be created by cloning (grafting) 30 trees of the best 15 families (i.e. 2 trees per family)
screened from the Main Population after detailed assessment of growth traits. The functions
of the Elite Population are:

(i) to accelerate genetic improvement by providing the best trees each generation for
controlled crosses and development of the very best possible clones for
deployment; 22
(ii) to provide best trees from the best families for establishment of clonal seed


The first thinning was carried out at 3 years of age in 1999 at Phu Ninh and in 2000 at Ba Vi.
This was a within-plot thinning; 3 trees in each line plot were removed, keeping only the
biggest straightest tree. The current stock density at each trial is about 400/ha. All 144
families were retained at Phu Ninh, but some inferior families were removed at Ba Vi
(Nguyen Duc Kien et al. 2007).

The operation of the main breeding population is summarised diagrammatically in Figure 3.
6.1.2 Elite population and clone bank/clonal seed orchard
Activities concerning elite population and clone bank/clonal seed orchard are summarised
diagrammatically in Figure 4.
23
Box 1. Chronological summary of E. urophylla improvement activities

1996-1997 Establishment of two open-pollinated progeny trials
Purpose First cycle breeding population to obtain genetic information and make accurate
selections of outstanding trees for clone bank and advanced breeding. Convert to
seedling seed orchards after selective thinning.
Location Two trials were established at Phu Ninh in 1996 and at Ba Vi in 1997.
Material 144 open-pollinated families from natural provenances in Indonesia.
Design Randomised latinised row-column design with 8 replicates, 4-tree line plot in each
replicate, spacing 4m between row and 1.5m within rows (1666/ha).

1999/2000 First thinning
Age at 3 years of age in 1999 in Phu Ninh trial and 2000 in Ba Vi.
Selection selection was within family only, the biggest straightest tree was retained in each line
plot and 3 trees were removed. The trees to remove were selected by eye, not from

2009 Controlled crossing
Purpose to create intra- and interspecific hybrids of E. urophylla

2010/2011 Establish seedling trials of the seeds from controlled crosses
Purpose identify the best hybrid families

2012/2013 Establish clone trials
Purpose identify superior clones for deployment 24
Figure 3. Improvement strategy for
E
. urophylla
main population
Year
Base
Population
Breeding
Population
Propagation
Population
Plantation
Forests
1996/97
144 families
from natural
provenances
provenance-
progeny trials

Population
Propagation
Population
Plantation
Forests
Year
1996/97
provenance-
progeny
trials at 2
sites
g
bank for
establishment
of clonal seed
orchard and
controlled
crossing
2009
2011
2013
Figure 4. Improvement strategy for
E. urophylla
elite population/clone bank
PT1
PT2
best 30 trees
2007
clonal seed
orchard ?