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African Journal of Biotechnology Vol. 7 (24), pp. 4393-4399, 17 December, 2008
Available online at http://www.academicjournals.org/AJB
ISSN 1684–5315 © 2008 Academic Journals
Full Length Research Paper
Evaluation of seed production of scots pine (Pinus
sylvestris L.) clonal seed orchard with cone analysis
method
Ahmet Sivaciolu* and Sezgin Ayan
Kastamonu University, Faculty of Forestry, Department of Forest Engineering, 37200 Kastamonu, Turkey.
Accepted 21 October, 2008
This research was carried out to investigate seed production in a 13 years-old scots pine (Pinus
sylvestris L.) clonal seed orchard, including 30 clones. Eight of cone and seed traits as number of fertile
and infertile scales, cone volume, cone number, filled and empty seed number, seed efficiency and 1000
seed weight were studied. Significant differences existed between the clones in all traits. The overall
mean of fertile scale number was 30.1 with a range of 19.8 to 42.2 among the clones while infertile scale
number was 41.1 with a range of 34.1 to 51.5. Overall mean of filled seed number, empty seed number
and filled seed percentage was 11.6, 15.0 and 43.6%, respectively. The cone number and cone volume
varied 33.4 to 287.88 and 6.6 to 18.2 cm3 among the clones, respectively. The average seed efficiency
for all clones was rather low and 17.9%. The overall mean of 1000 seed weight was found 10.9 g with a
range of 8.6 to 13.2 g. As to 1000 seed weight and filled seed number values, 0.68-19.33 kg of filled
seeds per hectare varying among the clones can be produced in this orchard. The cluster dendrogram
produced two groups; 18, 27, 26, 30 numbered clones in the first group and the others.
Key words: Pinus sylvestris, seed, orchard, clone, cone.
INTRODUCTION
Scots pine (Pinus sylvestris L.) is one of the most
common and important forest tree species in Turkey due
to usefulness of its wood to many commercial uses. Pure
stands of this species occupy roughly 750 000 ha (Genç,
2004). This species is classified as one of the economi-
cally important tree species for Turkish Forestry in the
“National Tree Breeding and Seed Production Program”
(Koski and Antola, 1993). For importance of this species,
in Turkish Forestry, planning, economical and biological
success of plantation are thus important issues. Of
course big amount of reproductive material is necessary
to keep present scots pine forest stock even to continue
with increasing trend by rehabilitating the degraded
areas. Presently, the need of scots pine seeds is approxi-
*Corresponding author. E-mail: asivacioglu@kastamonu.edu.tr.
Tel: +90 3662150900. Fax: + 90 366 2152316.
mately 715 kg per year (Bilir et al., 2007).
Demand for scots pine seeds and seedlings in Turkey
is obtained mainly by domestic production, but currently
only 9.2% of the Turkish seed demand in scots pine is
supplied from current 111 ha of seed orchards (Cengiz,
2003; Bilir et al., 2007). Most of these seed orchards are
still rather young. Nevertheless, new orchards have been
established to cover the demand of improved seed for
afforestation according to the national seed and tree
breeding program (Koski and Antola, 1993). High and
genetically improved seed yield from the seed orchard is
an integral part in the success of a tree breeding
program. If high seed production is to be maintained,
yields must be monitored, causes of seed losses must be
identified in the seed orchards. So, as all over the world,
in Turkey, orchard managers need a procedure to identify
and quantify seed production losses in scots pine. In
order to manage seed orchards effectively and efficiently,
managers need simple, reliable and practical methods to
4394 Afr. J. Biotechnol.
monitor the quantity and quality of seed crops, from the
time of seed-cone pollination to cone harvest.
There are some techniques for determining seed
production/efficiency in seed orchards. The cone analysis
method which is one these methods first used for red
pine (Pinus resinosa Ait.) by Lyons (1956). The method
was modified and further developed as a procedure for
evaluating seed production and seed efficiency, seed
losses in seed orchards (Bramlett, 1972). This method
provides information which is needed to evaluate and
modify orchard management procedures so that seed
yield can be maximized.
In this study, the seed production in a scots pine clonal
seed orchard was assessed by using cone analysis
method. The information obtained is very valuable in the
management practices of the existing scots pine clonal
seed orchards and can be also used for better planning
of advanced generation clonal seed orchards in Turkey.
MATERIALS AND METHODS
This study was carried out in Tekçam clonal seed orchard, located
at Taköprü, Kastamonu (41036' N, 35005' E, 1160 m). The orchard
was established in 1995 and comprises 1987 grafts of 30 clones
derived from intensively selected trees in Araç-Dereyayla seed
stand. Grafts were 2 years old at the time of establishment and
were planted at a spacing 6 x 6 m. Commercial cone harvesting
started in the 2003 when the grafts were 10 years old. By the time
of this study (2006), the graft age is 13 years. So far, no pruning
has been done in the orchard.
In all clones, ten replications (grafts) were sampled at random
and the cones, were harvested, and counted separately by graft
(ramet). Cones were collected in autumn 2006 when the seeds
were mature. The abundance and sources of pollen were not
monitored in the orchards for 2005 spring when the time of seed-
cone pollination. Each graft was divided into three levels according
to height. 12 of cones having no external damage were collected at
random from the middle level of graft between 1/3 and 2/3 of the
height. The cones were placed in individual paper bags and kept at
4°C until analysis.
The collected cones were classified into the pots and attended to
flex open the cone scales into the indoor condition. Ten grafts of 30
clones respectively were assessed for number of fertile/infertile
scales of graft (FScN and IFScN), number of cones/graft (CoN),
cone volume/graft (CoV), filled/empty seed number of graft (FSeN
and ESeN), seed efficiency (SE) and 1000 seed weight (g)/graft
(1000SW).
After opening the scales, they were systematically removed, one
by one, with forceps to determine the number of fertile and infertile
scales and remove the seeds. Fertile scales were located 4 in the
central portion of the cone and had two well developed ovules in
the form of a mature seed for pine species (Lyons, 1956; Bramlett
et al., 1977). After removing the seed wing, extracted seeds were
floated on water during 12-16 h. After that, number of empty and
filled seeds was counted. Cone number for per graft was counted
and cone volume was determined by thinking the cones as a
geometric cone. Seed efficiency is the ratio of the total number of
filled seeds to the seed potential (Bramlett et al., 1977). Seed
potential is the maximum number of seeds that a cone can produce
(two times the number of fertile scales) (Lyons, 1956).
Data were subjected to multi-way analysis of variance. Variables
were tested for normality and homogeneity of variances and
logarithmic transformation for FScN, IFScN, FSeN, ESeN, CoN,
arcsine for SE, were made. All pair wise comparisons of individual
means were done by the least significant differences (LSD). Diffe-
rences were considered significant at P < 0.05 level. Coefficient
variation among clones (CVC) and grafts (CVG) in percent was
estimated as the ratio of standard deviation of the clones/grafts to
arithmetic means. Relationships between eight of seed related
characters were tested using correlation analyses. Moreover,
dendrograms were constructed on the basis of Euclidean distances
by the nearest neighbourhood method to analyze the similarity
between clones as to the studied characters (Zar, 1999).
RESULTS AND DISCUSSION
The analysis of variance showed that there was signifi-
cant differences among clones at 0.001 and 0.01
probability level for all cone and seed characteristics
examined (Tables 1 and 2). All clones combined, scots
pine cones had a mean of 30.1 FScN with range among
the clones from 19.8 (clone 24) to 42.2 (clone 26). Thus,
as to the combined mean of FScN (30.1), each scots pine
cone had the potential to produce about 60 seeds. The
IFScN varied among the clones from 34.1 (clone 3) to
51.5 (clone 8) with overall mean 41.1 (Table 1). The
bigger CVG values than CVC show the bigger variation
within the clones than among the clones in the orchard.
As overall mean of the clones, there were 166.1 of
cones/graft in the orchard. The biggest value (287.88) of
CoN was estimated for clone 23, while the lowest value
(33.4) for clone 1 (Table 1). The big value of standard
error for CoN shows the variation within the clones.
It was found that cone volume was under strong
genetic control (Verheggen and Farmer, 1983; Stoehr
and Farmer, 1986). In this study, CoV varied among the
clones from 6.6 (clone 15) to 18.2 cm3 (clone 30) with
overall mean of 10.7 cm3 (Table 1).
The overall mean of FSeN and ESeN per clone was
11.6 and 15.0, respectively. It was found that filled seed
number per cone 9.9 for the same orchard in 2005 (Bilir
et al., 2007). This indicates the effect of age increasing to
seed production. FSeN, varied among the clones from
3.3 (clone 7) to 22.8 (clone 18) while ESeN varied from
6.5 (clone 9) to 25.8 (clone 2) (Table 2). The FSeN
variation in this study (3.3-22.8) is in the lower range with
Yazdani et al. (1995), who reported that total seeds per
cone varied between 9.3 and 21.8 in a scots pine clonal
seed orchard. Also, overall mean of filled seeds
percentage in this study was 43.6%. This value is varied
at 21.9-66.1% interval among the clones and at 8.22-
81.33% interval within the clones. The overall mean value
(43.6 %) of filled seed percentage is in the lower range of
what (Yazdani et al., 1995) reported. They showed that
the percentage of empty seeds per cone in clonal seed
orchard of scots pine ranged from 12% to 39%. Further-
more, the result is lower than 12% in average proportion
of empty seeds (88% of filled seeds) in open pollinated
Sivaciolu and Ayan 4395
Table 1. Mean values and multiple comparisons of studied cone related characters.
Cone related characters
Clone FScN IFScN CoV CoN
1 31.1±0.71 ef2 39.1±1.3 fghi 7.4±0.2 mn 33.4±7.9 n
2 36.4±0.9 bc 42.6±1.4 bcdef 10.6±0.3 efghi 80.2±25.3 kl
3 24.9±0.8 jkl 34.1±1.0 j 10.5±0.5 efghij 152.4±31.8 cdefghij
4 26.1±0.9 hijk 39.5±1.8 fghi 10.7±0.3 efghi 161.2±34.8 cdefghij
5 27.6±1.0 fghij 37.6±1.6 ghij 10.0±0.7 ghijk 74.8±29.6 lm
6 35.9±1.0 bcd 41.9±1.5 bcdefg 9.5±0.3 ghijk 219.6±50.4 abcde
7 25.5±0.8 hijk 46.7±1.4 abcd 8.2±0.3 klmn 119.6±27.2 ghijk
8 25.0±0.9 jkl 51.5±2.5 a 9.2±0.4 ghijkl 255.6±38.8 ab
9 25.6±0.7 ijkl 35.4±1.1 ij 10.8±0.3 efgh 135.2±34.9 efghij
10 33.7±1.0 cde 39.0±1.3 fghi 12.1±0.4 cde 250.8±49.4 abc
11 29.9±1.5 fghi 41.0±1.6 cdefg 11.0±0.8 efg 192.8±56.5 bcdefghij
12 31.4±0.9 def 43.3±1.5 bcdef 11.9±0.5 cdef 145.6±39.6 efghij
13 29.0±0.6 fgh 41.3±1.6 cdefg 10.4±0.6 efghij 94.6±16.5 ijkl
14 29.2±0.7 fgh 44.7±1.4 bcde 7.7±0.2 lmn 190.0±17.4 abcdef
15 27.0±0.7 ghij 34.3±1.0 j 6.6±0.2 n 186.6±28.9 abcdefg
16 24.0±1.0 kl 41.0±1.6 cdefgh 9.1±0.3 hijklm 121.4±43.8 jkl
17 30.6±1.0 efg 40.5±2.0 efghi 10.4±0.3 efghij 106.8±24.3 hijk
18 38.6±1.2 ab 47.0±1.3 ab 13.7±0.4 bcd 112.6±15.5 fghij
19 31.0±1.0 ef 37.2±1.6 ghij 9.9±0.5 ghijk 153.6±44.3 defghij
20 27.8±0.9 fghij 41.9±1.5 bcdefg 8.9±0.2 ijklm 200.6±48.7 abcdefg
21 30.8±0.6 ef 39.2±1.1 fghi 13.8±0.4 bc 190.4±27.7 abcdefg
22 30.0±0.8 eg 41.3±1.3 cdefg 10.1±0.4 fghij 158.0±27.0 bcdefghi
23 23.0±1.2 l 40.2±1.4 efgh 8.7±0.5 jklm 287.8±64.8 a
24 19.8±0.7 m 36.6±1.7 hij 7.4±0.2 mn 250.4±60.2 abcd
25 34.3±1.4 cde 41.0±1.7 defgh 11.9±0.6 def 197.0±63.0 abcdefgh
26 42.2±0.8 a 44.3±1.6 bcdef 14.3±0.3 b 255.2±35.6 ab
27 38.2±1.1 ab 41.1±1.8 cdefg 15.0±0.4 b 105.2±16.1 hijk
28 29.2±0.8 fgh 41.7±1.2 bcdefg 12.2±0.7 cde 251.8±34.1 ab
29 29.7±0.9 efg 40.7±1.6 efgh 9.3±0.5 ghijkl 241.2±35.6 abc
30 36.1±1.1 bc 46.0±1.6 abc 18.2±0.7 a 57.8±23.3 mn
Overall Mean 30.1±0.2 41.1±0.3 10.7±0.1 166.1±5.8
F value /Clone3
14.022*** 4.262*** 1.880** 8.276***
LSD4 0.055 0.054 5.491 0.241
F value /Graft 0.003ns 0.679ns 1.521ns 0.552ns
CVG (%) 21.49 15.97 30.53 60.98
CVC (%) 16.86 9.21 24.12 40.58
1Values are the means of 10 grafts and show as mean ± standard error.
2For each character, mean values with the same letter are not significantly different at P < 0.05 level;
3 ***: significant at P < 0.001; **: significant at P < 0.01; ns: none significant; 4The values of FScN, IFScN and CoN are transformed.
Pinus sylvestris, reported by Koski (1971). However, Bilir
et al. (2007) reported that the percentage of filled seeds
increases with increasing orchard age. So, the low filled
seeds percentage in this seed orchard can be explained
with the orchard age (13 years old as of 2006). The
percentage of filled seeds per cone is of vital interest
because it reflects the effectiveness of fertilization and
thus the amount of self-fertilization. Selfing causes empty
seeds in scots pine, and selfing results more often in
empty seeds than in vital selfed seeds (Lindgren, 1975).
The average SE for all clones was 17.9%. Although,
there is no estimates for Turkish clonal seed orchards by
using cone analysis about seed efficiency, this17.9%
value is quite low in comparison to literature, especially to
4396 Afr. J. Biotechnol.
Table 2. Mean values and multiple comparisons of studied seed related characters.
Seed related characters
Clone FSeN ESeN SE 1000SW
1 8.5±0.6 def 20.0±0.7 bc 13.4±0.9 jk 8.6±0.1 m
2 11.1±0.7 cde 25.8±1.2 a 14.7±0.9 hij 10.8±0.4 ghi
3 11.5±0.9 cde 10.5±0.7 j 22.6±1.4 bcd 12.5±0.3 abc
4 10.3±0.8 cde 9.8±0.9 j 18.9±1.2 defghi 10.9±0.2 fghi
5 12.7±1.1 cde 11.3±0.7 hij 21.2±1.6 cdef 10.0±0.2 jkl
6 12.6±0.8 cde 10.4±0.5 j 17.1±1.0 fghij 11.1±0.2 efghi
7 3.3±0.3 k 12.5±0.8 ij 5.3±0.6 m 10.5±0.2 ijk
8 6.1±0.7 fgh 11.1±1.0 j 10.4±1.1 kl 8.9±0.2 lm
9 12.7±0.8 bc 6.5±0.5 k 23.9±1.3 bcd 11.8±0.2 cdef
10 18.2±0.9 ab 21.4±0.9 ab 26.4±0.9 ab 11.8±0.2 cdefg
11 13.1±1.2 cde 10.0±0.7 j 20.3±1.3 defghi 12.0±0.3 bcd
12 12.2±0.9 bcd 18.1±0.7 bcde 19.1±1.3 defghi 11.4±0.2 defgh
13 12.2±0.6 bcd 19.1±0.9 bcd 20.7±0.9 cdef 10.8±0.3 fghi
14 9.9±0.5 cde 19.0±0.9 bcd 16.9±1.0 fghij 9.2±0.4 lm
15 7.9±0.6 efg 20.5±0.9 ab 14.5±1.0 ij 8.8±0.1 m
16 5.4±0.7 hij 13.3±0.9 fghi 9.8±1.0 kl 9.1±0.3 lm
17 10.3±0.8 cde 16.4±1.1 cdef 15.5±1.2 ghij 10.3±0.2 ijk
18 22.8±1.0 a 15.6±0.7 def 29.7±1.3 a 10.3±0.2 ijk
19 8.9±0.9 efg 15.4±1.1 defg 13.5±1.2 jk 11.9±0.3 bcd
20 5.7±0.6 ghi 11.4±0.8 hij 9.4±0.9 kl 10.8±0.2 hij
21 12.8±0.6 bc 16.1±0.7 cdef 20.7±0.9 cdef 13.1±0.2 a
22 10.5±0.6 cde 21.2±1.0 ab 17.2±0.8 efghij 11.4±0.2 defgh
23 4.9±0.7 ij 13.6±1.1 fgh 7.1±0.9 lm 9.8±0.3 kl
24 3.7±0.4 j 11.0±1.1 hij 7.2±0.8 lm 9.1±0.2 lm
25 14.2±1.1 bc 16.0±1.0 def 19.9±1.0 defg 11.9±0.3 bcde
26 21.3±0.9 a 17.6±0.7 bcde 25.2±1.0 abc 12.8±0.2 ab
27 21.4±1.2 a 21.5±1.1 ab 27.5±1.3 ab 11.5±0.2 cdefgh
28 13.4±0.8 bc 7.7±0.9 k 22.5±1.2 bcd 11.7±0.2 cdefgh
29 13.5±1.0 bc 14.9±0.8 efg 22.4±1.5 bcde 10.3±0.2 ijk
30 15.5±1.3 bc 12.2±0.9 ghij 19.9±1.5 defgh 13.2±0.4 a
Overall Mean 11.6±0.2 15.0±0.9 17.9±0.3 10.9±0.1
F value /Clone
14.174*** 16.915*** 15.349*** 14.668***
LSD5 0.170 0.160 3.660 0.968
F value /Graft 0.002ns 0.685ns 0.138ns 0.003ns
CVG (%) 53.72 38.30 44.63 15.33
CVC (%) 42.72 31.75 35.59 12.02
5 The values of FSeN and ESeN are transformed.
southern pines in USA, where values of 25% for seed
orchards with no protection from insects to 70% for seed
orchards with maximum protection might be expected
(Bramlett, 1987). The studied orchard is no protection
from insects. The lowest (5.3) SE was observed in clone
7 while the highest (29.7) for clone 18 (Table 2).
Overall mean of 1000SW was found 10.9 g with range
among the clones from 8.6 g (clone 1) to 13.2 g (clone
30) (Table 2). One of the advantages with seed orchard
seed is that the seed weight normally is higher than for
seed stand (Wennstrom, 2001). This is also shown in the
study where the average seed weight per seed was 10.9
mg. In accordance with this result, Bilir et al. (2007) found
mean weight of a seed 11.1 mg for three clonal seed
orchard of scots pine in Turkey. Boydak (1977) reported
a seed weight of 9.2 mg in natural populations of P.
Sivaciolu and Ayan 4397
Table 3. Pearson correlation coefficients among eight cone and variables.
Variable 1 2 3 4 5 6 7 8
1.FScN 1.000 0.198** 0.769** 0.473** 0.544** 0.639** 0.363** -0.195
2.IFScN 1.000 0.128* 0.052ns -0.005ns 0.195** -0.061ns 0.026ns
3.FSeN 1.000 0.274** 0.925** 0.659** 0.355** -0.096ns
4.ESeN 1.000 0.139* 0.177** 0.004ns -0.266ns
5.SE 1.000 0.542** 0.325** -0.098ns
6.CoV 1.000 0.659** -0.188ns
7.1000SW 1.000 0.019ns
8. CoN 1.000
ns: Non significant, **: significant at the 0.01 level, *: significant at the 0.05 level.
sylvestris in the middle part of Turkey. Also, Turna (2003)
and evik (2005) reported 9.9 and 10.1 mg from eleven
and nine Turkish scots pine populations, respectively.
The FSeN and 1000SW per cone or clone are
important genetic characteristics for estimation of seed
harvest from seed orchards or per hectare. In this study,
the mean FSeN is varied between 3.3-22.8 among the
clones and 0-33.1 within the clones. Also, the 1000SW
values are varied in 8.6-13.2 g interval among the clones
and in 7.1-15.9 g within the clones. As to these values in
this orchard 0.68-19.33 kg of filled seeds per hectare
varied among the clones can be produced. The seed
yield value of only one clone is above 15 kg/ha. For this
reason, in the second generation seed orchards, the
clones capable to produce copious seed should be widely
used in point of seed production. Also, in the seed
orchard the higher seed production is contributed by the
fact that the density is higher, stimulating early seed
production in this orchard. Seed crop per hectare in scots
pine may surpass 30 kg under climatically optimal
conditions of Central Europe and 15 kg in northern
Sweden (Matyas, 1991). In spite of the favorable climatic
conditions when compared to those locations, the seed
production is rather low in the studied orchard. The low
seed yield in this orchard may be explained with
young age of the orchard and disharmony in syn-
chronization among the clones.
When examine the relationships among the cone and
seed traits; the FScN had a stronger positive correlation
with CoV (r = 0.639) than IFScN (r = 0.195). Similarly, the
association between CoV and FSeN (r = 0 .659) was
greater than the association between CoV and the ESeN
(r = 0.177). There was a strong correlation between the
FScN and FSeN (r = 0.769) but correlation between
FScN and IFScN was weak (r = 0.198). SE was weakly
correlated with some of the cone measures (r = -0.005 to
0.139) except the FSeN (r = 0.925) as would be expected
and FScN (r=0.544). There was no correlation between
SE and IFScN at p0.01 level. The number of ESeN was
not strongly correlated with any of the other cone traits.
The 1000SW is strongly correlated with CoV. There was
no significant correlation between CoN per clone and all
the other traits (Table 3).
The results in this study of correlations between
characters are mainly in accordance with previous stu-
dies in P. sylvestris and other species. Positive significant
correlation (r=0.95) was found between yield of filled
seed per cone and total number of seeds per cone in a
clonal seed orchard of Pinus halepensis (Matziris, 1998).
Also, positive significant correlations were reported
among seed and cone characters in Pinus contorta (Ying
et al., 1985) and Pseudotsuga menziesii (Reynolds and
El-Kassaby, 1990). Positive and significant correlation
was also found between seed-cone crop size and filled
seed yield (r=0.93) in P. menziesii (El-Kassaby and Cook,
1994). Greene and Johnson (1994) found that seed
production is highly, inversely, correlated with the mean
seed mass.
On the cluster dendrogram constructed on the basis of
Euclidean distances with the use of the nearest neigh-
bourhood method for 8 quantitative seed and cone traits,
two distinct groups can be noticed: the first composed of
clones 18, 27, 26, 30 and the others (Figure 1).
Variation in cone production within the clones (5-465) is
greater than among the clones (33.4-287.8) as it is
shown by El-Kassaby et al. (1989) for P. menziesii. Also,
El-Kassaby and Cook (1994) reported that both seed-
cone and filled-seed production were under genetic
control in that species. Clonal variation in both seed and
cone production capability will not affect genetic compo-
sition of seed orchard seeds, but also the balance
between maximizing genetic gain and maintaining seed
production capacity at the time of seed orchard rogueing
(Ying and Illingworth, 1985). In Swedish seed orchards
the percentage of filled seeds is 88 and 73% at the top
and bottom of grafts, respectively. Also, the weight of
filled seeds varied between 6.4 to 6.6 mg (Prescher et al.,
2005). In this present study, the filled seed percentage
among the clones varied between 21.9 to 66.1%. And,
also the weight of filled seeds varied from 8.6 to 13.2 mg.
In that case, orchard seeds of Prescher et al. (2005)
seem to be about half as heavy as in studied orchard of
4398 Afr. J. Biotechnol.
Figure 1. Dendrogram of 30 clones of Pinus sylvestris based on 8 seed and
cone traits.
Turkey.
The variation between clones indicates that production
and quality of seed of scots pine can be improved by
selection. The size of genetic base must not be reduced.
Also, attention must be paid to these characteristics when
management of existed or establishment of new and
second generation seed orchards are made.
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