全 文 ：Journal of Forestry Research (2010) 21(4): 487−491
DOI 10.1007/s11676-010-0103-2





Variability in growth characteristics for different genotypes of Eucalyp-
tus tereticornis (SM.)

Kumar A • Luna RK • Parveen • Kumar V




Received: 2009-05-01; Accepted: 2010-06-01
© Northeast Forestry University and Springer-Verlag Berlin Heidelberg 2010

Abstract: Eighteen clones of Eucalyptus tereticornis (Sm.) were evalu-
ated for three years by adopting randomized block design for various
growth parameters at Hoshiarpur, Punjab, India and compared with two
checks. Significant variations were recorded for height, diameter at
breast height (DBH) and clear bole height (CBH). The broad sense
heritability was low to moderate for both height and CBH. The genetic
gain for height and CBH increased substantially per se with the increase
in age of trees. The average genetic gain for three years was recorded
maximum for height (159.60%) followed by DBH (110.97%) and CBH
(70.34%). Clone 17 attained maximum DBH over other genotypes for
second and third year followed by clones 14 and 11. Clone 5 showed an
upward trend for DBH and maintained its superiority for CBH as the age
of the tree increased. Similarly, clone 11 changed its ranking from 9th to
8th to 3rd for DBH and from 9th to 4th to 2nd for CBH, respectively for
the age of one, two and three years. Nonetheless, clones 6 and 10 per-
formed poorly for all the characters studied. Clones 17, 14 and 5 were
found to be the most promising clones for commercial deployment.
Keywords: Eucalyptus tereticornis; clones; heritability; genetic advance;
genetic gain


Introduction

The genus Eucalyptus belongs to the family Myrtaceae and
comprises about 700 species (Eldridge et al. 1993), and in India
mainly two species viz. E. tereticornis and E. camaldulensis have

The online version is available at http://www.springerlink.com
A. Kumar ( ) • Parveen
Division of Genetics and Tree Propagation, Forest Research Institute,
Dehradun-248006 Uttarakhand, India. E-mail: ak_meena@yahoo.com,
ashok@icfre.org. Tel: +91-135-2224379,. Fax: +91-135-2756865.
R. K. Luna • V. Kumar
Research & Development Circle, Punjab State Forest Department,
Hoshiarpur- 146001, Punjab, India.
Responsible editor: Yu Lei

been planted extensively owing to their faster growth rate and
short rotation for various end uses including pulp, wood, sawn
timber, fencing pole, firewood and extraction of aromatic oils
(Lal 2000). Though millions of seedlings of eucalypt are being
planted every year, the productivity has not been commensurat-
ing with the expected yield mainly due to poor quality of plant-
ing stock. In fact, the requirement of various woods in India by
2010 AD has been projected to 344 million tonnes of fuel wood
and charcoal, 37 million m3 of industrial wood, 33 million m3
sawn timber, 5.7 million m3 pulp and paper wood and 1.3 million
tonnes of wood based panels (Anon 1991; Lal 2000). In fact, the
Ministry of Environment and Forests, Government of India in its
‘State of Environment Report’ indicated that India occupies
2.41% of the world’s land area, of which 39% is degraded (Kar-
thawinata et al. 2000), but has to meet the demand of 16.40% of
the world’s populations. Unsustainable land use practices have
unfortunately been contributing immensely to such high degra-
dation of available geographical land mass (Anon 2009). The
situation has been alarming and immediate steps are required to
increase the productivity of forests substantially either by en-
hancing the total forest cover or per unit area. Ironically, it may
not be feasible to increase forest cover with large population size,
and the possible option to bridge the gap is to enhance the pro-
ductivity of existing forests and plantations by adopting clonal
forestry under various afforestation programmes.
Short rotation forest tree species like eucalyptus can play a
complementary role in bridging the gap between demand and
supply. The species exhibits enormous genetic variability and
differs significantly in quantitative and qualitative traits. The
assessment of genetic variability is a key to progress in tree im-
provement (Zobel, 1981) and is a useful tool in determining the
strategies for tree improvement and breeding of an important
species like eucalyptus. The plantations established from geneti-
cally uniform material are highly venerable to major climatic
factors or epidemic particularly for insects and diseases (Aradhya
and Phillips 1993). Using the variability, significant improvement
in the productivity of eucalyptus has been achieved in many
countries through the application of various genetic tools coupled
with clonal forestry, as the transfer of both additive and
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488
non-additive characters is routinely possible. The approach is
particularly attractive in capturing gains for traits that have low
heritability (Zobel 1981) and also in the exploitation of heterosis.
Using the approach, substantially higher productivity of euca-
lyptus has been achieved in Congo and Brazil. Aracruz Florestal
Company, Brazil could achieve dramatic yield increment upto
100 m3·ha-1·a-1 in clonal plantations. Even in India, the produc-
tivity of some of the Eucalyptus clones under un-irrigated condi-
tions has been reported to about 20-25 m3·ha-1·a-1 (Lal 2000).
The present study purports to test the superiority of different
clones for various growth parameters that ultimately influence
the productivity of the species. Once the promising clones are
identified in this species, the farmers, planters and paper-based
industries could deploy these clones on commercial scale for
industrial and domestic purposes.


Material and methods

A field trial consisting of 18 clones and two checks (one from the
clonal seed orchard and one from unknown seed source) of
Eucalyptus tereticornis was established at Hoshiarpur, Punjab
(31º3136N latitude, 75º4854E longitude, 267.30 m altitude
and 1242.2 mm rainfall) in Northern India. The plantations of the
species are mostly raised either by collecting from seed from an
unknown source or from the seed orchards. Therefore, it is
inevitable to develop the clone(s) which perform better than the
existing planting stocks, so that the productivity of newer
plantations established with improved genetic material is
enhanced to popularize among the growers. It was with this
background that two checks used to understand comparative
growth and productivity pattern of different clones. The
evaluation trial was established by adopting completely
randomised block design with three replication and twenty plants
of each genotype in a block of 20 plants (5×4). The trial was
established basically with a uniform spacing of 2 m × 2 m.
The clonal plants were raised by planting single nodal coppice
cuttings treated with 2000 μL·L-1 Indole Butyric Acid (IBA) in
48 h pre-soaked vermiculite filled-in 150 mL root trainers. The
root trainers were kept in the mist chamber for 45 days where
80%−85% relative humidity was maintained all the times. After
45 days, the rooted cuttings were weaned out first to the shade
house with 75% shading and then to the open conditions gradu-
ally to harden the rooted cuttings. After 15 days of hardening, the
plants were ready for field planting. At the same time, the seeds
of the checks were also sown in 150-mL root trainers filled with
above mentioned rooting media to ensure that the age of planting
material for both clonal stock and seedling is uniform at the time
of field planting. The trial was established in the field during
2005 and measured annually for height, diameter of breast height
(DBH) and clear bole height (CBH) continuously for three years.
The observations were collected upto the age three growing
years, which were analyzed for different genetic parameters,
using SAS (version 9.1.2 software for windows).
Analysis of variance: The observations were computed for
analysis of variance (ANOVA) as per Sukhatme and Amble
(1989).
Source of
variation
Degree of
freedom
Mean square
Expectation of
mean square
Clones C – 1 MSC σ2e + Rσ2c
Replications R – 1 MSR σ2e + Cσ2r
Residual (C - 1) (R – 1) MSE σ2e
Total RC – 1 - -
where, C and R are the number of clones and replications,
respectively. Similarly σ2e, σ2c and σ2r represent variance due to
composite residual, clones and replications, respectively.
Variance: The genotypic and phenotypic components of vari-
ance were calculated from the ANOVA as described by Burton
(1952).
Genotypic variance:
recReg /))(()( 2222 σσσσ −+=
where r represents number of replications

Phenotypic variance:
egp 222 )( σσσ +=
Genotypic Coefficient of variance:
GCV =(√σ²g /mean) × 100
Phenotypic coefficient of variance:
PCV= (√σ²p/mean) x 100
Heritability: Broad sense heritability was calculated as per
Lush (1949).
pgh 222 /σσ=
Genetic Advance: The genetic advance was calculated as de-
scribed by Johnson et al. (1955).
Gs = K. h2. √σ²p
where K is the selection intensity and calculated to 2.06
Genetic gain: The expected genetic gain, in per cent of mean,
was calculated following Burton and Devane (1953).
Genetic gain = (Gs/mean) × 100


Results and discussion

The genetic parameters are very useful tools in predicting the
amount of gain expected from clonal planting stocks and im-
proved seed of clonal seed orchards. The variation among the
clones is commonly used as an estimate of total genetic variation
and used to calculate the degree of genetic control for a particu-
lar trait (Foster and Shaw 1988). Though the selection of supe-
rior trees / ortets was carried out using index method of selection
with intensive selection criteria, genetic superiority per se needs
to be determined to identify a genetically superior clones / geno-
types. The yearly data obtained was analyzed and found that the
average height of the clones ranged from 268 to 526 cm for first
year, 482 to 814 cm for second year and 572 to 1031 cm for third
Journal of Forestry Research (2010) 21(4): 487−491

489
year, with a variation of 96.27%, 68.88% and 80.24% for first,
second and third year, respectively. The DBH ranged from 1.82
to 4.39 cm for first year, 3.76 to 6.69 cm for second year and
4.64 to 8.00 cm for third year, with a variation of 141.21%,
79.36% and 72.41% for first, second and third year, respectively.
Similarly, the clear bole height (CBH) ranged from 45 to 116 cm,
158 to 335 cm and 205 to 442 cm with 157.78%, 112.03% and
115.61% variability respectively for first, second and third years
(Table 1).

Table 1. Mean values for different characters in Eucalyptus tereticornis (Sm.)
First year Second year Third year
Genotype
Height (m) DBH (cm) CBH(cm) Height (m) DBH (cm) CBH (m) Height (m) DBH (cm) CBH (m)
1 4.07±1.04 3.16±1.50 0.95±0.42 7.15±1.93 6.04±2.00 2.64±1.00 8.83±2.23 6.97±2.24 3.27±1.17
2 3.88±1.25 3.16±1.46 1.16±0.48 6.96±2.58 5.99±3.03 2.29±1.03 7.86±2.74 6.63±3.34 2.62±0.93
3 3.89±1.38 3.53±4.29 0.80±0.33 7.36±2.38 5.90±2.54 2.28±0.75 9.01±2.95 6.84±2.90 3.02±1.17
4 3.27±1.41 3.13±6.52 0.73±0.35 5.52±2.55 4.51±2.96 1.94±0.73 6.94±3.45 5.37±3.35 2.53±1.06
5 4.09±1.80 2.47±1.44 1.16±0.52 8.14±3.10 5.56±2.52 3.35±1.22 9.42±4.33 7.18±2.84 4.42±1.71
6 2.68±1.11 1.91±1.54 0.45±0.29 4.82±2.06 3.76±2.47 1.58±0.74 5.72±2.53 4.64±2.81 2.05±1.04
7 3.66±2.02 2.47±1.79 0.92±0.41 6.72±2.76 5.07±2.95 2.65±1.04 8.42±3.62 6.03±3.00 3.09±0.89
8 3.66±0.90 2.66±1.04 0.90±0.37 6.60±1.71 5.65±2.05 2.15±0.76 8.23±2.01 6.93±2.49 2.71±0.93
9 4.09±0.83 3.21±0.98 0.79±0.40 7.17±1.39 6.28±1.43 2.49±0.87 8.48±2.09 7.04±1.97 2.92±1.12
10 2.92±1.02 1.82±0.91 0.62±0.36 4.94±1.85 4.10±1.93 1.89±0.77 6.53±2.08 5.11±2.02 2.36±0.98
11 3.95±0.99 2.87±1.17 0.94±0.50 7.14±1.78 5.82±1.84 2.63±0.70 8.28±1.94 7.25±8.74 3.28±1.19
12 5.26±1.18 4.39±5.37 0.94±0.44 7.18±2.16 5.98±1.19 2.55±0.25 9.88±1.66 7.23±1.71 2.96±0.72
13 3.05±1.00 2.11±1.14 0.75±0.49 5.47±1.93 4.37±2.24 1.97±0.81 6.42±2.47 5.10±2.72 2.58±1.22
14 5.18±0.83 4.26±4.61 0.97±0.36 8.03±1.18 6.22±1.36 2.57±0.55 10.31±1.59 7.66±1.78 3.17±0.67
15 3.85±1.21 2.76±1.15 0.69±0.36 6.31±1.71 4.93±1.83 2.29±0.79 7.64±1.76 6.08±2.16 2.88±0.90
16 3.49±1.17 2.56±1.38 1.08±0.36 5.88±2.01 5.22±2.56 2.18±0.81 7.58±2.57 6.32±3.11 2.77±1.09
17 4.54±1.29 3.65±1.39 1.10±0.74 7.35±1.56 6.69±1.77 2.41±0.91 8.47±1.40 8.00±1.96 3.04±0.78
18 3.41±1.29 2.28±1.22 0.71±0.37 5.94±2.19 5.01±2.40 2.01±0.93 7.30±2.48 6.12±2.80 2.61±0.99
CSO Seedlot 4.11±1.60 2.74±1.19 0.97±0.41 7.17±2.46 5.46±2.53 2.59±0.72 9.19±3.52 6.75±3.00 3.27±1.11
Unknown Seedlot 3.67±1.35 2.58±1.72 0.82±0.41 6.95±1.91 5.30±1.95 2.51±0.75 8.51±2.19 6.28±2.23 3.19±0.89
Average 3.84 2.89 0.87 6.64 5.39 2.35 8.15 6.48 2.94
Maximum 5.26 4.39 1.16 8.14 6.69 3.35 10.31 8.00 4.42
Minimum 2.68 1.82 0.45 4.82 3.76 1.58 5.72 4.64 2.05
Std. Dev. 0.65 0.69 0.18 0.94 0.78 0.38 1.18 0.90 0.48
DBH, diameter at breast height; CBH, clear bole height

The analysis of variance (ANOVA) for different genotypes
showed that the values are highly significant for all the parame-
ters studies (Table 2). Accordingly, the variance (genetic and
phenotypic), broad sense heritability, genetic advance and ge-
netic gain for height, diameter at breast height and clear bole
height were calculated and presented in Table 3. The genotypic
and phenotypic coefficient of variation for all the characters pro-
vided evidences for existence of adequate genotypic variations.
The analyzed results showed that height was the most important
trait with maximum genotypic coefficient of variation for all
three years of study followed by DBH and CBH (Table 3). The
results thus indicate that both height and DBH are the principal
characters for field evaluation of Eucalyptus and there is consid-
erable inter genotypic variation exists for further genetic im-
provement.
The heritability expresses the degree to which a character is
influenced by heredity as compared to the environment. Estima-
tion of broad sense heritability for various characters (Table 3)
showed low to moderate heritability for height (0.27, 0.28 and
0.48), DBH (0.13, 0.22 and 0.22) and CBH (0.18, 0.42 and 0.45)
for all three years respectively. The results are in agreement with
the studies carried out by Apiolaza et al. (2005) on E. globules to
report low heritability (0.20) for DBH during field evaluation of
eight sub-races in Tasmania. Similarly, low to moderate herita-
bility was recorded in E. globules and E. nitens for different ge-
netic parameters (Raymond 2002). The broad sense heritability
for height and tree volume in E. grandis was not only low to
moderate but also varied with changing environment and age
(Osorio et al. 2001). Nelson and Tauer (1987) in poplars also
reported moderate to high broad sense heritability for juvenile
traits like height, diameter, growth and leaf size. Kumar (2007)
also reported low to moderate heritability for height (0.31), di-
ameter at ground level (0.44) and diameter at breast height (0.37),
during field evaluation of 70 clones of Gmelina arborea. None-
theless, there is a need to estimate narrow-sense heritability for
individual growth components so that additive genetic variance
associated with individual growth components is calculated.
Thus these estimates usually facilitate selection on those traits
from which a positive genetic response can be expected at rea-
sonable selection intensity. In present study, the highest genetic
Journal of Forestry Research (2010) 21(4): 487−491

490
advance was observed for height (4.44, 9.27 and 18.25) followed
by DBH (3.28, 5.60 and 7.47) and CBH (0.28, 1.82 and 2.98). In
fact, the maximum average genetic gain (159.60 %) also reported
for height followed by DBH (110.97 %) and CBH (70.34 %).
Nonetheless, the genetic gain for third year was found to be
maximum (223.62, 115.35 and 100.99) for the height, DBH and
CBH, respectively, and was positive for all the traits. The genetic
gain per se increased substantially as the age of the trees in-
creased for height and CBH (Table 3).

Table 2. Analysis of variance for different traits of 20 genotypes of Eucalyptus tereticornis
Mean sum of squares
Height Diameter at breast height Clear bole height
Source of
variation
Degrees of
freedom
First year Second year Third year First year Second year Third year First year Second year Third year
Genotypes 19 25.54** 52.91** 83.24** 28.85** 36.33** 47.89** 2.06** 8.77** 13.94**
Replications 2 37.75 103.85 107.43 34.89 75.89 39.35 1.59 8.74 7.81
Residue 38 8.84 18.05 14.64 16.51 15.25 19.79 0.99 1.91 2.74
(** indicates level of significance at 1 percent)

Table 3. Different genetic parameters calculated for 20 genotypes of Eucalyptus tereticornis for three years of growth
Characters and yearly static
Height Diameter at breast height Clear bole height Genetic parameters
First year Second year Third year First year Second year Third year First year Second year Third year
Genetic variance 3.34 6.97 13.72 2.47 4.21 5.62 0.21 1.37 2.24
Phenotypic variance 12.17 25.02 28.35 18.98 19.46 25.41 1.20 3.28 4.97
Heritability (broad sense) 0.27 0.28 0.48 0.13 0.22 0.22 0.18 0.42 0.45
Genetic advance 4.44 9.27 18.25 3.28 5.60 7.47 0.28 1.82 2.98
Genetic gain 115.75 139.44 223.62 113.58 103.98 115.35 32.71 77.32 100.99
Genotypic coefficient of variance 43.52 52.42 84.07 42.70 39.09 43.36 12.30 29.07 37.97
Phenotypic coefficient of variance 158.49 188.14 173.71 328.34 180.56 196.06 69.20 69.53 84.24

The heritability, genetic advance and genetic gain were esti-
mated from an early age (12 months) to the age of log phase (36
months) after planting. The growth rate generally enters the log
phase from third or fourth years of age, thus heritability esti-
mates carried out after this age would be more reliable. Up to the
age of 36 months, the increasing trend of heritability for all the
traits is a positive sign and can be understood as pointer com-
pared with the results expected at a later stage of the evaluation.
The comparison of present results with upcoming results will
also enable establishment of genetic and age-age correlations.
Obviously, the results of present study would perceptively de-
termine whether genetic analysis at early stage is reliable for
making future perditions. If reliable, genetic assessment for other
population could also be carried out with suitable correlations or
the extent of relationship can be determined and suitable age-age
correlations. The results of preset study show that the clone 12
attained maximum height (526 cm) and DBH (4.39 cm), whereas
clone 5 attained maximum CBH (116 cm). In the second year,
clone 5 attained maximum height (814 cm) and CBH (335),
whereas clone 17 attained maximum DBH (6.69 cm). Similarly,
in third year clone 14 was found to attain maximum height (1031
cm), clone 17 attained maximum DBH (8.00 cm) and clone 5
with maximum CBH (442 cm). Clone 6 and 10 found to be the
least performers consistently for all the traits during entire study
period. Clone 5 was therefore the best performers for all the
characters and showed consistency in growth, and improved its
performance along the age. Similar trend was recorded for clones
17 and 14. These clones performed much better than that of the
checks and could therefore play a significant role if planted on
large scale commercially. However, their superiority needs to be
tested over some more period of time to make suitable recom-
mendations.
The clones in terms of mean DBH for all the years of assess-
ment were compared for their change in ranking within them-
selves (Table 4). Clone 17 was ranked 3rd in the first year but out
performed all the clones during 2nd and 3rd year of assessment
to rank 1st. Clones 11, 5, and 18 recorded an upward trend
whereas clones 3, 4 and 6 demonstrated a decreasing trend.
Though the average increment for these clones over mean DBH
from 1st to 3rd year was 125%, the clones 11, 8, 16, 5, 18, 10
and seed from CSO reported an increment of 153%, 161%, 147%,
191%, 168%, 181% and 146% respectively. The clones 3, 4 and
6 (decreasing trend) showed increment of 94%, 72% and 143%
respectively.
While developing similar relationship for CBH, clone 5 main-
tained its superiority over all the genotypes. Clones 11, seed
from CSO and unknown source changed ranking from 9th, 6th
and 12th to 2nd, 4th and 5th positions. However, there was a
sharp decrease in the ranking of clone 2 from 2nd position in first
year to 15th in third year. The decreasing trend was also recorded
for clones 13 and 4 (Table 5). Clones 10 and 6 performed poorly
and maintained lowest positions for entire duration of field
evaluation.

Journal of Forestry Research (2010) 21(4): 487−491

491
Table 4. Change in rank for different genotypes of Eucalyptus tereticornis
on the basis of DBH
Rank First year Second year Third year
1 4.39 (12) 6.69 (17) 8.00 (17)
2 4.26 (14) 6.28 (09) 7.66 (14)
3 3.65 (17) 6.22 (14) 7.25 (11)
4 3.53 (03) 6.04 (01) 7.23 (12)
5 3.21 (09) 5.99 (02) 7.18 (05)
6 3.16 (01) 5.98 (12) 7.04 (09)
7 3.16 (02) 5.90 (03) 6.97 (01)
8 3.13 (04) 5.82 (11) 6.93 (08)
9 2.87 (11) 5.65 (08) 6.84 (03)
10 2.76 (15) 5.56 (05) 6.75 (COS)
11 2.74 (COS) 5.46 (COS) 6.63 (02)
12 2.66 (08) 5.30 (SL) 6.32 (16)
13 2.58 (SL) 5.22 (16) 6.28 (SL)
14 2.56 (16) 5.07 (07) 6.12 (18)
15 2.47 (05) 5.01 (18) 6.08 (15)
16 2.47 (07) 4.93 (15) 6.03 (07)
17 2.28 (18) 4.51 (04) 5.37 (04)
18 2.11 (13) 4.37 (13) 5.11 (10)
19 1.91 (06) 4.10 (10) 5.10 (13)
20 1.82 (10) 3.76 (06) 4.64 (06)
Mean 2.89 5.39 6.48
Figures in parenthesis are the genotypes

Table 5. Change in rank for different genotypes of Eucalyptus tereticornis
on the basis of CBH
Rank First year Second year Third year
1 1.16 (05) 3.35 (05) 4.42 (05)
2 1.16 (02) 2.65 (07) 3.28 (11)
3 1.10 (17) 2.64 (01) 3.27 (01)
4 1.08 (16) 2.63 (11) 3.27 (CSO)
5 0.97 (14) 2.59 (CSO) 3.19 (SL)
6 0.97 (COS) 2.57 (14) 3.17 (14)
7 0.95 (01) 2.55 (12) 3.09 (07)
8 0.94 (12) 2.51 (SL) 3.04 (17)
9 0.94 (11) 2.49 (09) 3.02 (03)
10 0.92 (07) 2.41 (17) 2.96 (12)
11 0.90 (08) 2.29 (02) 2.92 (09)
12 0.82 (SL) 2.29 (15) 2.88 (15)
13 0.80 (03) 2.28 (03) 2.77 (16)
14 0.79 (09) 2.18 (16) 2.71 (08)
15 0.75 (13) 2.15 (08) 2.62 (02)
16 0.73 (04) 2.01 (18) 2.61 (18)
17 0.71 (18) 1.97 (13) 2.58 (13)
18 0.69 (15) 1.94 (04) 2.53 (04)
19 0.62 (10) 1.89 (10) 2.36 (10)
20 0.45 (06) 1.58 (06) 2.05 (06)
Figures in parenthesis are the genotype

The trend in ranking of different genotypes indicates that the
field evaluation and testing of these clones needs to be carried
out for longer duration, so that elite genotypes are screened and
deployed through plantations programmes. It is also necessary to
examine the trend of all the clones over the years as to group
different clones on the basis of end uses. The early starters could
well be used to raise biomass plantations for paper industry,
whereas slow starters may be recommended for timber and fur-
niture industry. However, individual clones need to be analysed
for different wood properties before recommending their de-
ployment through plantations programmes. Nonetheless, de-
scribed results indicate clonal growth pattern of different clones
at a single location and needs to be tested for real the analysis of
adaptability through G×E interaction and superiority per se.


References

Anon. 1991. Forestry statistics today for tomorrow. Wood and wood products
1961–1989 : 2010. Food and Agriculture Organization of the United Na-
tions, Rome.
Anon. 2009. Water crisis and land degradation. Indian Environment Report,
Ministry of Environment & Forest, Government of India, New Delhi.
Apiolaza LA, Raymond CA, Yeo BJ. 2005. Genetic varation of physical and
chemical wood properties of Eucalyptus globules. Silvae Genetica, 54 (4/5):
160–166.
Aradhya KM, Phillips VD. 1993. Gentetic variability in fourteen provenances
of eucalyptus species in Hawaii. Silvae Genetica, 42 (1): 9–15.
Burton GW. 1952. Quantitative inheritance in grass. 6th International Grass-
land Congress, Part I: 277–283.
Burton GW, Devane EH. 1953. Estimating heritability in tall fecue (Festuca
arundinaceae) from replicated clonal material. Agron J, 45: 478–481.
Eldridge K, Davidson JC, Hardwood, Wyk G. 1993. Eucalyptus domestica-
tion and breeding. New York: Clarendon Press, Oxford, 288 pp.
Foster GS, Shaw DV. 1988. Using clonal replicates to explore genetic varia-
tion in a perennial plant species. Theor Appl Genet, 76: 788–794.
Johnson HK, Rabinson HF, Comstock RE. 1955. Estimates of genetic and
environmental variability in soybeans. Agron J, 47: 314–318.
Kartawinata K, Riswan S, Gintings AN, Puspitojati T. 2000. An over view of
post extraction secondary forests in Indonesia. In: Proc., Workshop on
Tropical Secondary Forests in Asia: Reality and Perspectives, 10-14 April,
2000, Centre of International Forestry Research, Bogor, Indonesia,
Kumar A. 2007. Growth performance and variability in different clones of
Gmelina arborea (Roxb.). Silvae Genetica, 56(1): 32–36.
LAL P. 2000. National forest policy and raw materials: Supply by wood
industries in India. Indian Forester, 126(4): 351–366.
Lush IL. 1949. Heritability of quantitative characters in farm animals. Heridi-
tas, 35(Supl.1): 356–387.
Nelson CD, Tauer CG. 1987. Genetic variation in juvenile characteristics of
Populus deltoides from southern Great Plains. Silvae Genetica, 36:
216–221.
Osorio LF, White TL, Huber DA. 2001. Age trends of heritability and geno-
type-by-environment interactions for growth traits and wood density for
clonal Eucalyptus grandis Hill ex Maiden. Silvae Genetica, 50(3/4):
108–117.
Raymond CA. 2002. Genetics of Eucalyptus wood properties. Annals of For-
est Sciences, 59: 525 – 531.
Sukhatme PV, Amble VN. 1989. Statistical Methods for Agricultural Workers.
New Delhi: Publication and Information Division, ICAR.
Zobel BJ. 1981. Vegetative propagation in forest management operations. In:
Proc, 16th South For Tree Improv Meet, Blacksburg, Virginia. pp.
149–159.