Gmelina arborea

1. Philippine Journal of Crop Science (PJCS) April 2012, 37 (1):27-35
Copyright 2012, Crop Science Society of the Philippines
Full Paper
Root Growth Potential, Variability and Heritability of Yemane (Gmelina
arborea Roxb) in the Philippines
Onofre S. Corpuz
Cotabato Foundation of Science and Technology, Doroluman Arakan, 9417 Cotabato, Philippines;
nfr_uplb@yahoo.com
The experiment was undertaken to characterize root growth potential (RGP) and determine growth
variability and heritability of eight hundred Yemane (Gmelina arborea Roxb) based on provenance in 3
provinces in the Philippines. Significant variations of morphological characteristics of seedlings of
Yemane by seed sources were found in the study. Seed sources from Quezon and Cotabato Provinces
differed in all morphological traits compared with the seed sources from Davao del Sur. The root growth
potential in terms of the number of first order lateral roots (FOLR) was positively correlated with all
seedlings morphological characters, such as root collar diameter, primary root length, stem height, and
root:shoot ratio. The frequency distribution of FOLR revealed to be normal. The seedlings FOLR was fro m
3 to 35 with an average of 18. Three natural FOLR groupings were established such as: R1 (0–10); R2 (11–
20); and R3 (21–30+). The entire traits measured were genetically influenced by the seed sources based
on observed high heritability estimates.
Keywords: FOLR, heritability, RGP, variability
INTRODUCTION
Strategies in assessing quality of planting stocks need
to veer away from using the traditional approach of
looking only into the sound morphological
characteristics of seedlings to be planted (Grossnickle
et al. 1991). These morphological indices however,
often fail to account for difference in seedling
physiology. Hence, holistic assessment of stock
quality requires the integration of both morphological
and physiological attributes of seedlings (Carandang
1994). Consideration of both attributes provides an
effective appraisal of the fitness of seedlings for field
planting purposes.
In the Philippines, many studies on seedling attributes
dealt with morphological traits, while only few were
done in root growth in relation to field planting
performance. Lateral root development of large leaf
mahogany (Swietenia macrophylla King) (Carandang
1994), and root growth potential of narra
(Pterocarpus indicus Willd.) transplants (Gazal 1998)
were among the studies conducted in the country.
Root growth potential (RGP) is the ability of a tree
seedling to initiate and elongate roots when placed
into an environment favorable for root growth. The
magnitude of RGP is often correlated with survival and
seedling growth following outplanting (Ritchie 1984).
The RGP develops in seedlings at the nursery or
greenhouse. Following planting, the expression of
RGP or actual root growth, is affected by soil
temperature, soil moisture, and other factors (Ritchie
1984). The RGP is measured by growing seedlings for
certain period under environment favorable to
enhance root growth, before assessment for the
amount of roots developed is done. RGP is the most
reliable predictor of field performance in trees (Ritchie
1984).
Root growth potential is seldom used as a measure of
seedling quality.
Studies elsewhere were done
mainly to temperate tree species, such as: Pinus
radiata (Rook 1971); Sitka spruce (Deans et al. 1990),
Douglas-fir (Sharpe and Mason 1992; Rose et al.
1991, Haase and Rose 1994), Loblolly pines (Larsen
1986; Williams et al.1988; Feret and Krebs 1985),
Slash pine (McGrath and Duryea 1994), and
Ponderosa pine (Stone and Jenkinson 1959).
Methods of measuring RGP have been standardized
in many temperate countries, but have not been done
in the tropics including Philippines. Thus the potential
of using RGP as an indicator of seedling quality and
performance of one important tree species in the
Philippines need to be explored. This study attempts
to provide a basis for interpreting RGP and heritability
of Yemane, one of the most common exotic tree
species used for reforestation and plantation in the
country at present.
In this study, four seed sources of Yemane seeds in
three provincial locations in the Philippines were
tested for RGP, variability and heritability. The
objectives of this study were: i) to characterize the
RGP of Yemane based on provenance, ii) to test

2. whether RGP is closely related to stem and other root
morphological characteristics, and iii) to determine the
frequency distribution and family mean heritability of
first order lateral root of the species.
N
W
E
S
Quezon
North Cotabato
Davao D el Sur
Them e1.s hp
MATERIALS AND METHODS
The experiment was conducted at the Agroforestry
Nursery of Matalam Cotabato, Philippines for 2
months (6 September– 6 November, 2006). One
seedbed lined with plastic sheet at the bottom was
constructed. The bed was walled with bamboo slats
and filled with a top soil up to a height of 30.48 cm.
Eight hundred seeds (200 per provenance) from three
provincial sources (Figure 1) were sown in a seed bed
with shallow drills 3 cm apart following a Completely
Randomized Design with four replications. Seeds
from Candelaria, Quezon were purchased from
Ecosystems Research and Development Bureau,
College Laguna while seeds from Cotabato and
Davao were personally collected by the researcher 1
month before sowing.
Seedlings were grown for 60 days. Watering and
weeding operations were done to attain optimum
germination. The soils in the seedbeds with a ratio of
1:2 sand and garden soil were sterilized before
sowing the seeds. Growing plants were not applied
with fertilizer and chemicals within the 60 days
growing period.
After 60 days, the seedlings were carefully lifted from
the seedbed and washed with running water
throughout to remove excess soil particles. Number of
first order lateral roots (FOLR) (Figure 2) that
developed were counted to establish root groupings
for Yemane by seed source. Root collar diameter,
stem height and length of the primary root were also
measured. Root collar diameter, the portion of the
seedling where white pigment portion of the shoot to
root system starts, was measured using a vernier
caliper. Stem height was measured from the root
collar to the tip of the seedling, while the length of the
primary root was measured from the root collar to the
tip of the root.
Data Analysis
The initial individual family and the subsequent
consolidated datasets that were collected were
subjected to ANOVA using statistical analysis system
(SAS) version 5.
The relationship of number of lateral roots counted
with the other roots and stem morphological
characters of the species as influenced by seed
sources were determined by correlation analysis. Root
classes were set based on recognized natural
groupings by provenance. The distributions of the
28
100
0
100
200
Mile s
Figure 1. Map showing the study site Matalam and
provincial seed sources of Yemane used in
the study.
Figure 2. First order lateral roots (FOLR) of Yemane
seedlings.
number of lateral roots were examined using
Kolmogorov’s goodness of fit test. The hypothesis of
approximate
normality
was
tested
using
untransformed
data.
Seedling
morphological
characters are then subjected to ANOVA based on
the groupings established, such as: 0–10 (low) 11–20
(medium); 21–30 + (high).
Root Growth Variability and Heritability of Yemane

3. 2
h=
MS F - MSFxR
MS F
25
20
No. of FOLR
Family mean heritability of all seedlings morphological
characters were estimated based on the ANOVA of
plot means. The narrow sense heritability was
computed using the following equation derived from
ANOVA:
15
10
Where: h2 = Narrow sense heritability
MSF = Mean square value for family
MSFxR = Mean square value for family by
replication interaction
5
b
a
0
Bansalan
Dvo. Sur
Candelaria,
Quezon
Root Collar Diameter
Highly significant variation in root collar diameter was
observed among seedlings coming from various
sources. Seedlings from Kabacan, Cotabato and
Candelaria, Quezon differed in diameter with the
seedlings from Bansalan, Davao del Sur and Arakan,
Cotabato. The highest mean collar diameter was (0.36
cm) from Kabacan, Cotabato, followed by Quezon
(0.35 cm), while the lowest was found with the
seedlings from Arakan, Cotabato (0.24 cm) (Figure 5).
Length of the Primary Roots
Primary root length of seedlings from the four seed
sources varied significantly. The seedlings with the
longest primary roots were recorded from seeds
obtained in Candelaria, Quezon (20.60 cm) and
Kabacan, Cotabato (19.10 cm). Shortest primary roots
were obtained from seedlings coming from Davao del
Sur (11.52 cm) (Figure 6).
OS Corpuz
Arakan,
Cotabato
3.
Number of first order lateral roots of
Yemane from different seed sources in
the Philippines.
25
Stem Height (cm)
Stem Height
The four seed sources varied significantly in terms of
stem height. Longest shoot was observed in the
seedlings obtained from Candelaria, Quezon with an
average stem height of 23.55 cm. Seedlings from
Bansalan, Davao del Sur had the shortest mean stem
(16.17 cm) (Figure 4) but did not vary with the seeds
coming from Cotabato and Quezon Provinces.
Figure
20
15
10
5
a
b
b
b
0
Bansalan Candelaria, Kabacan,
Dvo. Sur Quezon Cotabato
Arakan,
Cotabato
SEED SOURCES
Figure 4. Stem height (cm) of Yemane from different
seed sources in the Philippines.
0.35
Root Collar Diameter
(cm)
Number of first order lateral roots (FOLR)
The different seed sources of Yemane significantly
differed in terms of number of FOLR. Seeds from
Kabacan, Cotabato and Candelaria, Quezon were
significantly different from the seeds sourced from
Arakan, Cotabato and Bansalan, Davao del Sur.
Highest average number of FOLR was found in
Kabacan, Cotabato (21.36) followed by Quezon
(19.83) but were not significantly different. The lowest
mean (12.49) was obtained from Davao del Sur
materials (Figure 3).
Kabacan,
Cotabato
SEED SOURCES
RESULTS
Variation in Morphological Characteristics of
Yemane Seedlings
a
b
0.3
0.25
0.2
0.15
0.1
0.05
a
b
b
a
0
Bansalan Candelaria, Kabacan,
Dvo. Sur
Quezon Cotabato
Arakan,
Cotabato
SEED SOURCES
Figure 5. Root collar diameter of Yemane from different
seed sources in the Philippines.
29

4. 1.0
20
15
10
5
a
b
b
a
Root/shoot Ratio
Primary Root Lenght
(cm)
25
0
Bansalan Candelaria, Kabacan,
Dvo. Sur
Quezon Cotabato
Arakan,
Cotabato
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Bansalan
Dvo. Sur
SEED SOURCES
Root:Shoot Ratio
The root:shoot ratio of seedlings from Candelaria,
Quezon differed significantly with those from
Bansalan, Davao del Sur and Arakan, Cotabato but
did not differ with those from Kabacan, Cotabato.
Highest mean root:shoot ratio (0.900) was observed in
seeds coming from Candelaria, Quezon, followed by
Kabacan, Cotabato (0.823) while the lowest was from
Arakan, Cotabato (0.712) (Figure 7).
Frequency Distribution of First Order Lateral
Roots in Seedlings of Yemane
Considering all the experimental seedlings regardless
of seed sources, the number of first order lateral roots
in 2 month-old seedlings of Yemane was found to be
normally distributed (Figure 8). Despite being a
discrete variable, a large population of 1,100
experimental seedlings caused approximation of
normal distribution. Test for approximate normality
using the untransformed values of number of FOLR
observed by Kolmogorov’s goodness of fit procedure
further affirmed the appearance of the curve. The
lowest number counted was 4, while the highest was
35. Both extreme values accounted for only a seedling
each. Seedlings with 18 FOLR were counted the
most. This findings emphasized that FOLR growth in
Yemane is not affected by population and
provenance.
Table 1 shows that greater number of seedlings fall
under Classes 2 and 3. It can be inferred that 2 month
-old seedlings of Yemane have 11- 30 first order
lateral roots. Seedlings with more than 31 FOLR are
exceptions and their occurrence under normal
conditions may not be that significant. The initial
FOLR groupings were empirically determined as low
(0 to 6), medium (7 to 12), and high (12) in northern
red oak (Quercusrubra) seedlings (Kormanik et al.
2002).
30
Candelaria,
Quezon
ab
Kabacan,
Cotabato
b
Arakan,
Cotabato
SEED SOURCES
Figure 7. Root:shoot ratio of Yemane seedlings from
different seed sources in the Philippines.
120
Cumulative Frequency
(%)
100
No. of Seedlings
Figure 6. Primary root length (cm) of Yemane from
different seed sources in the Philippines.
a
b
80
60
40
Frequency
20
0
1
3
5
7
9 11 13 15 17 19 21 23 25 27 29 31 33
Frequency/Cumulative Percent
Figure 8. Frequency distribution and cumulative percent
of FOLRs of seedlings of Yemane from
different seed sources in the Philippines.
Table 1. Categories of Yemane seedlings based on
number of FOLRs.
Class
1
2
3
Number of FOLR
0 – 10
11 – 20
21 – 30 & Up
Percent of Total
Seedlings
16.55
47.00
36.45
Variation in Seedling Morphological
Characteristics Based on FOLR Categories
It has been observed that all the morphological
characters exhibited highly significant variations
among classes of FOLR. Remarkable increase in the
length of seedling primary roots as the number of
FOLR increases was observed. The longest average
Root growth variability and heritability of Yemane

5. length of primary roots was obtained in Class 3
seedlings, having more than 30 FOLRs, while the
shortest in Class 1, having a maximum of 10 FOLRs.
Although remarkable and significant increase in stem
height and root collar diameter of seedlings were
observed among classes of FOLR, ranking of the
three root classes in terms of root:shoot ratio did not
differ (Table 2). Nonetheless, the mean shoot height
did not differ between Class 2 and Class 3, but were
significantly higher than seedlings in Class 1 (Table 2).
Table 2. Variations in the different morphological features
of Yemane seedlings based on first order lateral
roots categories.
The average collar diameter differed across the 3 root
classes. Collar diameter progressive by increased
with necessary FOLR. The highest collar diameter
seedlings belonging to the Class 3 with a mean root
collar diameter of 0.30 cm. The lowest average stem
diameter on the other hand, (0.25cm) was noted in
Class 1.
Table 3. Pearson correlation coefficient between number
of FOLR and seedling morphological characters
of Yemane.
The primary root length of Classes 1 and 3 differed
significantly, but both are statistically similar to Class
2. The longest roots (18.2 cm) in Class 3 was
significantly varied with Class 1 (15.7 cm) but
insignificantly different with Class 2 (17.0 cm) (Table 2).
**highly significant
* significant at 0.05 level
Shoot
Height
Collar
Diameter
1
2
3
19.271 a
21.943 b
22.633 b
0.2515 a
0.2836 b
0.3045 c
15.730 a
16.963 ab
18.151 b
Means with the same letters are not significantly different at p 0.05 using
LSD test.
Seedling Trait
Stem height
Root collar diameter
Root length
Root:shoot ratio
All correlations were determined to be high (0.590.89) and were statistically significant. Highest
correlation with the number of FOLR was observed on
collar diameter of seedlings (r=0.88) while the lowest
was on root:shoot ratio (R = 0.59). This implies that
with increasing FOLR, stem height, root collar
diameter, root length and root:shoot ratio increases,
thus developing a healthy and vigorous seedlings.
Family Mean Heritability Estimates for Seedling
Morphological Traits
Narrow sense heritability estimates for the various
seedling morphological characteristics of Yemane
seedlings were generally high. Highest genetic control
appears to be in FOLR (h2=0.89) followed by root
length (h2=0.87), root collar diameter (h2=0.85),
root:shoot ratio (h2=0.88) and the lowest was stem
height (h20.21) (Figure 9).
R
0.7082**
0.8838**
0.8217**
0.58599*
Prob>lRl
0.0022
0.0001
0.0001
0.0179
1
0.8
0.6
0.4
0.2
0
HERITABILITY
Correlation Between FOLR and other Seedling
Morphological Traits
The number of FOLR in the seedlings of Yemane
were positively correlated with other roots and stem
morphological characteristics (Table 3).
Root:
Shoot
Ratio
0.78002 a
0.82624 a
0.84494 a
Root
Length
Heritability Estimates
Average root:shoot ratio followed increasing trend
similar to that of the classes of lateral roots. This
finding is consistent with the findings of Carandang
(1994). Seedlings with the most desirable form ratio
belong to the highest class while seedlings with the
poorest form ratio belonged to those with less than 10
FOLRs but this observation is not significant in the
study conducted.
Root
Class
FOLR
Height
Dia.
Root L.
RSR
0.8929
0.2081
0.8458
0.8714
0.5386
SEEDLING TRAITS
Figure 9. Family mean heritability of Yemane seedlings
from four locations in the Philippines.
DISCUSSION
The ranking of the seed sources are relatively
consistent in all seedling morphological traits. It was
apparent that the seedlings from Candelaria, Quezon
and USM Kabacan, Cotabato consistently showed
superior morphological values in all parameters
measured. Either of the two location source rank first
in the five seedling morphological traits considered in
the study. The reverse is true with the seedlings
sourced from Bansalan, Davao del Sur and Arakan,
Cotabato. Either of the 2 location source ranked less
in all seedling morphological traits. Thus, among the
four seed sources studied, Quezon or Kabacan,
Cotabato would be the best choice as source of seeds
for quality seedlings.
The significant variations in seedling morphological
characters among the different seed sources of
Yemane in the Philippines is not surprising, since only
OS Corpuz
31

6. three provinces were considered in the study. Tree
species in most cases are reservoir of extensive
variations in almost all traits with the exceptions of
those in the clonal plantations as reported by
Carandang (1994). Tree species are products of long
evolutionary forces and most tree populations are still
in the wild state. Perry (1978) stated that forest
geneticists, tree breeders or tree improvement
workers are quite fortunate to be working with an
undisturbed pool of natural variability that has
developed over a long period of time.
Stands of trees within a given site may differ, much
more within different locations. This is a clear category
of variability that the present study dealt with. Usually,
the genetic differences in such stands are relatively
small, but there are times when unexplained pockets
of variation are found (Ledig and Fryer 1971). This is
especially true for form characteristics which usually
slightly differ genetically for trees on any common site
(Carandang 1994).
Individual trees of a species may also greatly vary
from one another even if grown under similar
condition. This is another type of variation
encountered in the present study using Yemane. This
is also the major type of variation that is valuable in
tree improvement works particularly in the choice of
the most appropriate selection procedure and the
development of a breeding program for a particular
tree species.
The presence of significant variations among the
sources of seeds of Yemane considered in the study
is an indication that selection for the qualify seedling
characteristics will work among the various stands of
species in the Quezon, Cotabato and Davao del Sur
provinces. Previously, Carandang (1994) found
significant differences among different seedling
morphological traits such as root length, shoot length,
stem diameter, shoot weight, total weight, and
root:shoot ratio of large leaf mahogany in Mt. Makiling
Forest Reserve. Tumaliuan (1983), also found
significant variations among parent trees of agoho
(Casuarina
equisetifolia
Forst)
in
different
provenances, in terms of seedling height, root collar
diameter and total dry weight.
The manner in which the seedlings are categorized
based on the number of first order lateral roots could
be very subjective. In the present study, more number
of categories involving narrower ranges of FOLR
number is still possible but, one has to bear in mind
that the practical usefulness of making lateral root
growth as a criterion for seedling stock assessment
should take into consideration the simplicity of
operation (Carandang 1994). Duryea and McClain
(1984) stated that the developments in forest nursery
operations must integrate a number of seedling
physiological and morphological attributes in seedling
stock assessment. Implicit therefore in the target
32
seedling concept is the development of simple grading
schemes using minimum, maximum and standard
values for as many seedling parameters as possible
(Rose et al. 1990). The three classes established in
the study are deemed appropriate for field testing. As
shown in Table 4, a comparison of unclassified and
classified seedling morphological traits revealed the
same result. Unclassified seedlings are ungrouped
seedlings in terms of root classes, while classified
seedlings are those that are grouped based on
number of
FOLRs. Variability
in
seedling
morphological characters exists among the three root
classes defined. As indicated in the result of the study,
the three root categories significantly varied among
seedlings morphological traits tested in the study.
Table 4. Comparison of significant variation in seedling
traits between unclassified and classified
seedlings according to the number of lateral
roots
Seedling
Trait
Stem height
Root collar diameter
Length of primary root
Root:shoot ratio
Unclassified
Seedlings
s
s
s
s
Classified
Seedlings
s
s
s
s
s – significant at 5% level
It should be emphasized that the root classes of
seedlings of Yemane in this study is an initial attempt
at establishing seedling quality of the species based
on RGP. The groupings made in this study based on
the number of FOLR may further be refined and or
modified when more studies are conducted to
determine the reproducibility of the scheme for
Yemane. This has been the experience of Kormanik,
Muse and Sung (1992) with loblolly pine as cited by
Carandang (1994).
Kormanik (1986) showed that, within reasonable limits
of seedling bed density, the number of first order
lateral roots was not markedly affected by common
nursery
cultural
management
techniques.
Furthermore, nursery field experiments have shown
that regardless of the phenotypic characteristics of a
sweetgum and other tree, associated progeny have a
predictable frequency distribution when seedlings are
stratified by first order lateral roots. Kormanik and
Ruehle (1986) have also made lateral root counts on
walnut (Juglans nigra L.), northern red oak, green ash
(Fraxinus pennsylvanica Marsh), and long-leaf pine
(Pinus palustris Mill.) and found relationship between
roots and other seedling traits. By combining minimum
seedling size and counts of lateral roots, they
estimated that more than 60% of the walnut and red
oak should be culled. This finding is in agreement with
the results reported by Johnson (1984) from a 7-year
field study with northern red oak. With further trials on
the consistency of variability of stem and root
characters, there is reason to believe that the initial
result of the study is reproducible.
Root growth variability and heritability of Yemane

7. The results of this study indicate that the FOLR
categories developed for seedlings of Yemane are
positively associated with the other seedling
morphological traits. Shoot length, collar diameter,
root length, and root:shoot ratio generally increased
according to increasing categories of FOLR number.
The use of the number of FOLR as an expression of
seedling quality finds merit in its positive correlations
with the other seedling morphological traits
considered in the study. All morphological features
specifically height and stem diameter, currently
provide the best estimate of seedling performance
after outplanting (Mexal and Landis 1990). Diameter is
considered to be one of the best predictor of field
survival while height seems to predict height growth in
plantation (Ritchie 1984). Root morphology is highly
correlated with both height and collar diameter which
support the earlier findings of Mexal and Landis
(1990).
Root morphology, specifically the number of FOLR is
more useful as an indicator of growth considering the
trend towards the use of root growth potential as an
indicator of early field performance and subsequent
growth (Larsen et al. 1986; Ritchie and Dunlap 1980).
As a measure of root growth potential (Stone and
Schubert 1959; Burdett 1979), the number of lateral
roots is widely adopted in physiological grading of
forest nursery seedling stocks.
The positive correlation of FOLR with stem and other
root morphological characters as observed is highly
significant. Operational experiences tend to indicate
that, other factors being equal, seedlings with large
stem diameter outperform those with smaller ones
(Chavasse 1990; Cleary et al. 1979; Sutton 1979).
When seedlings are carefully lifted as what has been
done in the study, stem diameter is closely related
with root morphological characters particularly number
of FOLR. The findings confirmed with Rowan (1986)
which stated that at harvest, large diameter seedlings
have more primary root laterals. While it is possible
that large diameter seedlings inherently have a more
fibrous root system, it is more likely that smaller
seedlings have thinner primary lateral roots that are
more easily stripped during lifting operations
(Carandang 1994). The improved field performance
ascribed to larger diameter may partially, be the result
of decreased root stripping. Blake et al. (1989) found
that the relationship between field survival and
seedling diameter was also affected by root mass
especially for smaller diameter seedlings. Seedlings
with good root mass consistently survived better than
those with poor root mass. The positive correlation of
FOLR growth with stem diameter and seedling height
has some physiological basis. Evidences from the
works of Richardson (1957; 1958) point to the fact that
lateral root initiation and growth are influenced by both
nutritional and hormonal factors derived from the
shoot.
OS Corpuz
Significance of the Family Mean Heritability
Estimates
Heritability was originally defined by Lush as the
proportion of phenotypic variance among individuals
in a population that is due to heritable genetic effects
(Nyquist 1991). It also indicates the degree to which
parents pass their characteristics along to their
offspring (Zobel and Talbert 1984). In the context of
the present study, the heritability estimates of the
different seedling morphological traits provide
information on the extent in which the said traits are
genetically controlled. High heritability values then
means that a variation among families in the particular
seedling morphological trait is largely due to the
differences in the genetic constitution of the individual
families. Estimates of family heritability in the study
are of the narrow sense (h2) which defines the ratio of
the additive genetic variance to the total variance. At
the start, it is important to know that the different traits
of seedlings of Yemane will only apply to the particular
population of the species in the three seed sources
(e.g. Quezon, Cotabato and Davao Sur). Only
Cotabato Province was replicated in terms of seed
source, such as Kabacan and Arakan, Cotabato, so
that these values are not fixed and are simply
determined to provide a general idea of the extent of
genetic control and strength of inheritance of the said
characters.
With the exception of stem height, all other seedling
morphological traits of Yemane in the four seed
sources were found to be highly controlled genetically
as shown by the high heritability estimates of all
morphological traits (Figure 6). This finding confirms
that genetically determined variation exists in root
system of plants (Street 1957). Brisette (1990)
recognized that genetics plays a critical role in
determining root system development of forest trees,
both in the nursery and in outplanting.
Kormanik (1986) contended that while stem diameter
maybe considered a better indicator of seedling vigor,
it cannot fully explain the differences in seedling
performance after outplanting. Webb (1969) earlier
cautioned against using stem diameter when
comparing early plantation performance of sweetgum
seedlings from the same family when grown at varying
seedling bed densities. This is because stem diameter
represents a seedling’s response to edaphic
conditions. Nursery cultural conditions such as
seedling bed density, fertility, moisture and
mycorrhizal conditions have been shown to affect
stem diameter. Unfortunately, the edaphic conditions
that stimulate stem diameter increases are not found
in the field. Kormanik’s study on sweetgum revealed
that the distributions of seedlings among root grades
remained relatively constant within an open pollinated
mother tree seedlot. This finding led to his
recommendation that seedling grading based on
lateral root morphology maybe a practical way to
identify the seedlings with the best potential.
33

8. CONCLUSION
Variability and strong genetic control of FOLR of
Yemane seedlings from the three provincial seed
sources were found in the study. The seedlings in the
different root classes vary in terms of morphological
traits such as stem height, collar diameter, root length,
and root:shoot ratio. Seedling stem diameter was
highly related with FOLR such that, stem diameter can
be good indicator of field performance, Candelaria,
Quezon and USM Kabacan, Cotabato are better seed
sources when establishing Yemane plantations in
Matalam, Cotabato because of their superior seedling
morphological traits.
RECOMMENDATIONS
It says that the ultimate test of the quality of seedling
is its early performance after outplanting and its
subsequent growth during the early years in
plantation. The lateral root classes established in this
study will be further tested in terms of early field
performance in the succeeding experiment. The RGP
interactions with cropping pattern, sources of seeds
and distance of planting will also be considered.
This study revealed that variations in root and stem
characteristics exist among the four locations (three
provinces in the Philippines) of seed sources of
Yemane. A study should be conducted to determine if
such variations will be evident also among the other
locations in the Philippines with consideration on
seeds coming from other municipalities within a
province. Only Cotabato province has two locations
considered in this study.
REFERENCES
Campo del AD, Carrillo RMN, Hermoso J, Ibanez AJ.
2006. Relationship between root growth potential
and field performance. Ann. Forestry Science 64
(2007) 541-548.
Burdett AN. 1979. New methods of measuring root
growth capacity: their value in assessing
Lodgepole stock quality, Canadian Journal of
Forest Research. 9: 63: 67.
Carandang WM. 1994. Lateral root development and
seedling performance of large leaf mahogany
(Swietenia macrophylla King). [Ph.D Thesis]
College, Laguna, Philippines: University of the
Philippines Los Baños. 223 p (Available at UPLB
Library).
Chavasse CGR. 1990. Planting stock quality. A
review of factors affecting performance. New
Zealand Journal of Forestry 25: 144-171.
34
Cleary BD, Greaves RD, Hermann RK. 1978.
Regenerating Oregon’s Forests. Oregon State
University Extension Center, Corvallis, Oregon.
OR. 287 p.
Corpuz OS. 2011. Root growth of four hardwood tree
species in the Philippines. The Center for
Sustainable Development. CSDi Community
http://www.csd-i.org/read-forest-trees-docs/. Nov.
5, 2011.
Corpuz OS 2011. Growth, survival and heritability of
Yemane as affected by provenance, root classes
and spatial arrangement. In: Sales EK, Editor.
Proc. Commission on Higher Education Zonal
Center for Region IX, XII, CARAGA. Proc.
National
Research
and
Development
Conference, Davao City, Philippines. 48 p.
Corpuz OS, Abas EL, Sambayon JA. 2011. Growth
and heritability of three year old Gmelina
plantation. In: Sales EK, Editor. Proc.
Commission on Higher Education Zonal Center
for Region IX, XII, CARAGA. Proc. National
Research and Development Conference, Davao
City, Philippines. 48 p.
Corpuz OS, Carandang WM, Visco RG, Lapitan RL,
Castillo ASA. 2009. Root growth potential as
affected by planting distance and provenance on
the growth and survival of Gmelina arborea.
World Agroforestry Centre. 2009. Book of
Abstracts, 2nd World Congress of Agroforestry,
Agroforestry - The Future of Global Land Use.
Nairobi: World Agroforestry Centre.
Corpuz OS, Carandang WM. 2011. RGP of selected
tropical hardwood tree species in the Philippines
as affected by root pruning. In: Sales EK, Editor.
Proc. Commission on Higher Education Zonal
Center for Region IX, XII, CARAGA. Proc.
National
Research
and
Development
Conference, Davao City, Philippines. 48 p.
Corpuz OS, Carandang WM. 2011. Effect of root
growth potential, planting distance and
provenance on the growth and survival of
Gmelina arborea Roxb. The Asian International
Journal of Life Sciences. ASIA Life Sciences 21
(1): 1-18, 2012.
Corpuz OS, Carandang WM. 2012. Root Growth
Potentials and Heritability of Gmelina arborea. 1st
ed. LAP LAMBERT Academic Publishing.
Germany. 256 p.
Duryea ML, McClain KM. 1984. Altering seedling
physiology to improve reforestation success. In:
Huryea and Brown (eds). Seedling Physiology
and Reforestation Success. MartinusNijhoff/Dr.
W. Junk Publishers. The Hague. p 77-114.
Root growth potential, variability and heritability of Yemane

9. Feret DD, Kreb RE. 1985. Seedling root growth
potential as an indicator of loblolly pine field
performance. Forest Science 31 (4): 1005-1011.
13-17, 1990. Roseburg, Oregon USDA Forest
Service. Rocky Mountain Forest and range Exp.
Sta. Gen. Tech Rep. RM 200.
Gazal RN. 1998. Effect of Soil moisture and root
growth potential of Narra (Pterocarpus indicus
Willd) transplants. M.S Thesis, UPLB, College,
Laguna. (Available at UPLB Library).
Nyquist WE. 1991. Estimation of heritability and
predictions of selection response in plant
populations. Crit. Rev. Plant Science 10:235-322.
Gazal RN, Blanchie CE, Carandang WM. 2004. Root
growth potential and seedling morphological
attributes of narra (Pterocarpus indicus Willd.)
transplants.Forest Ecology and Management 195
(2004) 259–266
Grossnickle SC, Major JE, Arnott JT, Lemay VM.
1991. Stock quality assessment through an
integrated approach. New Forests 5:77-91.
1991.
Haase DL, Rose R. 1994. Effects of soil water content
and initial root volume on the nutrient status of
2+0 Douglas-fir seedlings. New Forests 8:265277.
Johnson PS. 1984. Response of planted northern oak
to three overstorey treatments. Canadian Journal
of Forestry Research 14 (4):536-542.
Kormanik PP, Sung SS, Kass D, Samoch SJ. 2002.
Effect of Seedling Size and First-Order Lateral
Roots on Early Development of Northern Red
Oak on A Mesic Site: Eleventh-Year Results.
U.S. Department of Agriculture, Forest Service,
Southern Research Station. pp 332-337
Kormanik PP. 1986. Lateral root morphology as an
expression of sweetgum seedling quality. Forest
Science 32(3):595-604.
Kormanik PP, Muse HD. 1986. Lateral roots: a
potential indicator of nursery seedling quality.
TAPPI, 28 September-01 October 1986.
Larsen HS, South DB, Boyer JM. 1986. Root growth
potential, seedling morphology and bud
dormancy correlates with survival of Loblolly pine
seedlings planted in December in Alabama, Tree
Physiology 1:253-263.
Perry DA. 1978. Variation between and within tree
species. IUFRO Proc. Ecology of Evan-aged
plantations. p. 71-98
Ritchie GA. 1984. Assessing seedling quality. In:
Duryea ML, Landis TD, editors. Forest nursery
manual: Production of bare root seedlings.
Boston (MA) : MartinusNijhoff/Dr. W. Junk
Publishers. p. 243-260.
Ritchie GA, Tanaka Y, Meade R, Duke SD. 1993.
Field survival and early height growth of Douglasfir rooted cuttings: relationship to stem diameter
and root system quality. Forest Ecology and
Management 60:237-256.
Rook DA. 1971. Effect of undercutting and wrenching
on growth of Pinus radiata D. Don Seedlings. DA
Rook- The Journal of Applied Ecology, 1971JSTOR.
Rose R, Carlson WC, Morgan P. 1990. The Target
Seedling Concept. In: Rose, R.,Campbell, S.J.,
Landis, T.D. (Eds.), Target Seedling Symposium:
Proceedings, Combined Meeting of the Western
Forest Nursery Associations. USDA Forest
Service, Rocky Mountain Forest and Range
Experiment Station. Gen. Tech. Rep. RM-200, p.
1–8.
Rose R, Atkinson M, Gleason J, Sabin T. 1991. Root
volume as a grading criterion to improve field
performance of Douglas-fir seedlings. New
Forest Species. 195 -209.
Ruehle JL, Kormanik PP. 1986. Lateral root
morphology: a potential indicator of seedling
quality in northern red oak. Asheville (NC): USDA
Forest Service, Southeastern Forest Experiment
Station. Research Note SE-344. 6 p.
Ledig FL, Fryer JH. 1975. A pocket of variability in
Pinusrigida. Evolution 26(2):259-266.
Stone EC, Schubert GH. 1959. Root regeneration by
Ponderosa pine seedlings, lifted at different time
of the year. Forestry Science 5: 322 -332.
McGrath DA, Duryea ML. 1994. Increasing pine
survival
and early growth by planting
morphologically improved seedlings. New For. 8:
335–350.
Stone EC, Jenkinson JL. 1970. Physiological grading
of ponderosa pine nursery stock. Journal of
Forestry 69:31-33.
Mexal JG, Landis TD. 1990. Target seedling
concepts; height and diameter. Pp. 77-36. In:
Rose R, Campbell SJ, Landis TD (eds). Proc.
Target seedling symposium, combine meeting of
the Western Forest Nursery Associations, August
OS Corpuz
Sutton RF. 1979. Planting stock quality and Grading.
Forest Ecology and Management 2:123-132.
Sutton RF. 1990. Root growth capacity in coniferous
forest trees. Hort Science 25:259-266.
35