Natural Resources, 2012, 3, 66-70
http://dx.doi.org/10.4236/nr.2012.32010 Published Online June 2012 (http://www.SciRP.org/journal/nr)
Study on Varieties Combination Suitable for Mutual
Pollination of Yan Mountain Chestnut*
Qian Wang, Shuchai Su#, Di Zhao, Yanru Kou
Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing Forestry University, Beijing, China.
Received February 29th, 2012; revised March 25th, 2012; accepted April 8th, 2012
ABSTRACT
In order to improve the yield and quality of new varieties Castanea mollissima cv. “Zipo”, Castanea mollissima cv.
“Zunyu” and traditional Yan Mountain cultivars Castanea mollissima cv. “Duanci”, Castanea mollissima cv.
“Yanhong”, Castanea mollissima cv. “Dong lin gmingzhu ”, an experiment was carried out to study varieties combination
that was suitable for their pollination. Fruiting rate and seed-setting rate were used to decide which the most suitable
configuration was. The result indicated that: Castanea mollissima cv. “Zunyu” was the best pollination tree for
Castanea mollissima cv. “Yanhong”, Castanea mollissima cv. “Zipo” and Castanea mollissima cv. “Duanci”; C astanea
mollissima cv. “Duanci” was regarded as the best pollination tree for Castanea mollissima cv. “Zunyu”; the best variety to
comply with Castanea mollissima cv. “Donglingmingzhu” was Castanea mollissima “Zunyu” and Castanea mollissima cv.
“Duanci”; Castanea mollissima cv. “Zunyu” and Castanea mollissima cv. “Duanci” complied with each other best.
Appropriate configuration of pollination varieties turned out to be one of the key measures to improve the yield and
quality of chestnu t, while irrational combination may even bring the reduction of output.
Keywords: Castanea Mollissimabl; Conf iguration; Fruiting Rate; Seed-Setting Rate
1. Introduction
Chestnut (Castanea mollissi m a) was considered as one of
Chinese endemic species and the nutrient-rich nuts have
unique flavor, with great economic value [1]. Yan Moun-
tain chestnuts mainly grow in Qianxi, Zunhua, Xinglong,
Kuancheng, Qinglong counties, Hebei province and
Huairou, Miyun, Pinggu and Changping in Beijing. All
of the chestnuts here have exquisite shape, delicate meat
with high sugar content. The nuts are famous for fried
with the trade name “Tianjin Sweet Chestnut” or “Jing-
Dong Chestnuts.” The varieties mainly cultivated in Yan
Mountain region are Yanghong, YanChang, YanMing,
Timazhenzhu, Zipo, Zunyu, Huai Huang, Huaijiu, Zun-
huaduanci and so on. Castanea mollissima is a typical kind
of cross-pollination plants and its self-pollination seed-
setting rate is very low which reached only 10% to 40%
[2].
A number of related studies had been done by many
scholars. Such as Mokay, he has already proven that the
phenomenon self-infertility on some chestnut seedling
trees was due to incompatibility between male gametes
and female gametes [3]. In addition, the stigma of pistil
has strong selectivity on pollen, as a result, affinity among
pollination combinations of different species are different.
The test cross exp eriments on combinations o f pollinati on
varieties conducted by Wenbang Fan and other experts
showed that fruiting rate was low when self-pollination
and became high when cross-pollination [4].
Seedlings occupied the majority in all original chestnut
parks. Therefore, each tree differs from others genoty-
pically and they can be interactive with each other when
pollination. However, with improvement of commercial
value of chestnut, the fine varieties are vigorously promot-
ed and all breeding varieties became almost the same
genotype. Due to large-scale cultivation involving the
exclusive use of the same species, high empty shell rate
and low seed-setting rate increasingly appeared. Cross-
pollination should be fully considered and pollination
varieties should be well arranged in chestnut cultivation,
otherwise production will be greatly reduced [5]. There-
fore, to make clear of pollination and fruiting characteris-
tics and appropriate combination of pollination varieties
is one of the key measures to improve the yield and qua-
lity of chestnut. Although some research about cross-
pollination effect on fruiting rate has been done, they
have not been applied to production. And almost no stud y
*The study was funded by “Public Welfare Project of Forestry Industry
(201204401)” and “National Science and Technology Supported Pro-
gram (2006BAD01A1703-1)”.
#Corresponding author.

Study on Varieties Combination Suitable for Mutual Pollination of Yan Mountain Chestnut 67
on combination of pollination trees about chestnuts has
been reported till now.
In this experiment, new varieties Castanea mollissima
cv. “Zipo”, Castanea mollissima cv. “Zunyu” which were
bred during “The Eleventh Five-year Plan” in China and
the traditional Yan Mountain cultivars Castanea mollis-
sima cv. “Duanci”, Castanea mollissima cv. “Yanhong”,
Castanea mollissima cv. “Donglingmingzhu” were chosen
as materials for the study of varieties combination which
is suitable for their pollination. In addition, fruiting rate
and seed-setting rate of female parents were used to
decide which the most suitable configuration was. The
last purpose of this paper is to provide a theoretical basis
for scientific combination of the pollination varieties for
new chestnut orchard.
2. Materials and Methods
2.1. Varieties Selection and Combinations
According to research objectives, new varieties Castanea
mollissima cv. “Zipo”, Castanea mollissima cv. “Zunyu”,
which were bred during “The Eleventh Five-Year Plan” in
China and the traditional Yan Mountain cultivars Casta-
nea mollissima cv. “Duanci”, Castanea mollissima cv.
“Yanhong”, Castanea mollissima cv. “Donglingmingzhu”
were selected for mutual pollination on the basis of
germplasm resources survey. Pollens of all 5 varieties
were respectively collected for reciprocal pollination.
Each variety was pollinated with the other four varieties
and there were totally 20 combin ations. Variet ies selectio n
and pollination combinations design are as followed in
Table 1.
2.2. Test Site
The po llination exp eriment was carried out in the chestnut
breeding base in Zunhua City, Hebei Province which is
located at 40˚11'50"N latitude and 117˚58'30"E longi-
tude. It is in the north of Tangshan City and belongs to
warm temperate semi-humid monsoon climate and has
four distinct seasons. The annual average sunshine hours
is 2608.2 hours, annual average temperature is 10.9˚C, and
lowest temperature is –25.7˚C. Frost-free period reaches
182 days and its precipitation is 724.7 millimeters. This
chestnut breeding base was selected as the test site was
because Zunhua is one of the main chestnut production
bases in north China.
Zunhua Chestnut mainly distributed in northern and
western mountains areas along the Great Wall which is
rich in gneiss. Weathered gneiss soils which contains large
number of iron, managanese, sulfur, boron and other
inorganic nutrients, coupled with low temperatures, larg e
temperature difference and abundant rainfall here, make
it suitable for growth of chestnut.
2.3. Test Method and Process
The research materials were healthy chestnut trees which
were 20-year-old, non-pest, well-managed and in similar
growth situations. 15 trees of Castanea mollissima cv.
“Yanhong”, “Zunyu”, “Zipo”, “Donglingmingzhu” and
“Duanci” were respectively and randomly selected as
female parents. 7 - 8 similar female flowers in the east,
west, north and south of each tree (totally 30) were picked
out for pollination.
Chestnut flowers follow the leaves, appearing in mid-
dle of May and reached its full flowering stage onto late
May. As a consequence, the pollination experiment was
carried out during May and the follow-up testing was
respectively conducted in June when all th e male flowers
withered and September when chestnut matured.
May 8, 2010-May 13, 2010: Ziplock bags were applied
to bag the female flowers before their stigmas’s appearing.
May 15, 2010-May 24, 2010: It was the most appropriate
season for pollination when the angle between stigma and
stigma became 30˚ - 45˚ and most anther of male inflo-
rescence turned yellow from green at this time. Ziplock
bags were removed before pollens of inflorescence were
directly applied to female stigmas. Then they were put on
to the female flowers again immediately after the
pollination. The job was repeated 3 da ys later.
June 15, 2010: All male flowers have withered and
bags were taken off from the female flowers. Tags were
hanged to branches to indicate male parents and fruiting
rates were calculated.
September 17, 2010-September 27, 2010: Gather chest-
nut and investigate their empty shell rate, seed-setting
rate after the chestnut was harvested.
Table 1. Pollination combinations design.
female
male A (“Yanhong”) B (“Zunyu”) C (“Zipo”) D (“Dongling mingzhu”) E(“Duanci”)
A (“Yanhong”) - A × B A × C A × D A × E
B (“Zunyu”) B × A - B × C B × D B × E
C (“Zipo”) C × A C × B - C × D C × E
D (“Dongling mingzhu”) D × A D × B D × C - D × E
E (“Duanci”) E × A E × B E × C E × D -

Study on Varieties Combination Suitable for Mutual Pollination of Yan Mountain Chestnut 68
2.4. Statistics
The numbers of female inflorescence was recorded when
pollinating. The fruiting condition was written down
while ziplock bags were removed after all male flowers
had withered and the numbers of empty shell were re-
corded when chestnuts were collected.
The experimental data, in which self-pollination com-
binations were considered as the CK, were analyzed by
average method and One-way ANOVA, applying mean
square error test method by spss17.0 statistical software.
3. Result
3.1. Affect from Different Combinations on
Fruiting Rate and Seed-Setting Rate
Empty shell of chestnut, commonly known as no fruit,
means nuts in shells did not develop or just leave the seed
coat [6-8]. It is considered as no empty shell even when
there is only one seed in it. To some extent, the level of
seed-setting rate can be used as indicator for strength of
pollinator affinity. That is, the higher the seed-setting rate
is, the stronger the affinity will be and it could be consid-
ered as a good combination [9].
The fruiting rate and seed-setting rate of 5 varieties
Castanea mollissima cv. “Yanhong” (A), Castanea mollis-
sima cv. “Zunyu” (B), Castanea mollissima cv. “Zipo” (C),
Castanea mollissima cv. “Donglingmingzhu” (D), Ca sta nea
mollissima cv. “Duanci” (E) are followed as Figures 1-5.
It can be seen from Figure 1 that: Seed-setting rate of
E × A, which reached 94.59%, was the highest in 4 com-
binations, but its fruiting rate was low, only 47.52%, in-
dicating that fruiting rate and seed-setting rate is not so
consistent with each other. In contrast, both fruiting rate
(84.95%) and seed-setting rate (79.43%) of B × A were
very high. Seed-setting rate of D × A was 90.00%, while
fruiting rate which was 72.37% was lower than that of B
c
a
b
aa
aa
bb
a
40
60
80
100
120
g rate an d see d -
ttin g r ate/%
0
20
B
Fru
× AC × AD × AE × ACK
Combina erent male parents
itin
se
tions of Yanhong (A) with diff
fruiting rate seed-setting rate
differences in 5% level. Letters in bold de-
ed differences among seed-setting rate and those letters
not in bold showedting rate.)
Figure 1. Fruiting conditions of Yanhong (A) under differ-
ent pollinations. (a: From Figures 1-5 small letters on the
ost indicatep
scrib differences among frui
b
c
a
e
d
a
bb
80
100
ed-
aa
60
rate a
g rate/%
0
A × BC × BD × BE × BCK
Combin ations of Zunyu(B) with different male parents
Fr
20
40
uiting
settin nd se
fruiting rate seed-setting rate
Figure 2. Fruiting conditions of Zunyu (B) under different
pollinations.
b
d
c
e
a
a
ab
ab
b
ab
0
20
40
60
80
100
A × C
F ru itin g rate an d se ed -
se ttin g ra te/%
B × CD × CE × CCK
Combinations of Zipo (C) with d i fferent male parents
fruiting rate seed-setting rate
Figure 3. Fruiting conditions of Zipo (C) under different
pollinations.
c
d
a
d
bab
a
cbc
a
40
60
80
100
tin g rate an d se ed -
etting rate/%
0
20
A × DB × DC × DE ×DCK
Combinations of Donglingmingzhu (D) with d i fferent male
parents
Fr s
fruiting rate seed-setting rate
u i
Figure 4. Fruiting conditions of Donglingmingzhu (D) under
different pollinations.
a
a
a
c
bc
c
b
c
b
60
80
100
ate and seed-
rate/%
0
20
40
A × EB × EC × ED × ECK
Combinations of Duanci (E) with different male parents
Fruiting r
setting
fruiting rate seed-setting rate
Figure 5. Fruiting conditions of Duanci (E) under different
pollinations.

Study on Varieties Combination Suitable for Mutual Pollination of Yan Mountain Chestnut 69
× A. Fruiting rate and seed-setting rate of Castanea
mollissima cv. “Yanhong” (A) who had been under natu-
ra l pollinat ion were 53.4 5% and 7 7.78%. As a result, Cas-
tanea mollissima cv. “Zunyu” (B) was the best pollina tion
Ae 2: Fruiting rate of E × B,
a mollissima cv.
to be the best pollination tree for
cv. “Duanci” (E).
nd
g Conditions
What’s more, fruiting conditions of cross combination
fferent
withre
anci” (E) was Cas-
ing rate and
6%. Conse-
eties. Conse-
qu
tree for Castanea mollissima cv. “Yanhong” (A).
s we can see from Figur
which reached 83.33%, was significantly higher than that
of the other 3 combinations. Seed-setting rate of E × B
was 81.60%, although lower than combination D × B,
whose seed-setting rate was 90.54%, significantly higher
than its fruiting rate 38.95%. Fruiting rate of Castanea
mollissima cv. “Zunyu” (B), who had been in natural pol-
lination, was only 71.27%, far below fruiting rate of E ×
B. Thus, Castanea mollissima cv. “Duanci” (E) was re-
garded as the best pollination tree for Castan ea mollissima
cv. “Zunyu” (B).
It can be seen from Figure 3 that fruiting rate and
seed-setting rate of combination B × C were 86.61% and
87.33%, both of which were significantly higher than
that of other 3 combinations. Fruiting rate and seed-set-
ting rate of Castanea mollissima cv. “zipo” (C) were
51.34% and 80.65% in natural pollination, and they re-
spectively increased significantly by 35.27% and 7.08%
after pollinated by Castanea mollissima cv. “zunyu” (B).
So the result presented here indicated that the best variety
to comply with Castanea mollissima cv. “zipo” (C) is Cas-
tanea mollissima cv. “zunyu” (B).
It can be observed from Figure 4 that seed-setting rate
of C × D is significantly higher than that of other 3 com-
binations, who reached 87.21%, but fruiting rate was low,
only 57.33%. Both fruiting rate and seed-setting rate of A
× D became lower than that of B × D. In contrast, fruit-
ing conditions of B × D and E × D showed significant
advantages than that of Castanea mollissima cv. “Dong-
lingmingzhu” (D) under natural pollination for fruiting
rate and seed-setting rate of B × D achiev ed 80.86% and
86.96%, and E × D reached 83.15%, 81.65%. Thus, the
best variety to comply with Castanea mollissima cv.
“Dong-lingmingzhu” (D) were Castanea mollissima cv.
“Zunyu” (B) and Castanea m oll i ssi ma cv. “Duanci” (E).
Figure 5 showed that fruiting condition of B × E was
obviously better than that of A × E, C × E and D × E,
whose fruiting rate got to 79.00% and seed-setting rate
reached 89.45%. Though seed-setting rate of D × E be-
came the highest of the 4 combinations, its fruiting rate
was very low, only 44.50%, significantly lower than that
of Castanea mollissima cv. “Donglingmingzhu” (D) under
natural pollination. As a result, Castane
“Zunyu” (B) turned out
Castanea mollissima
3.2. Relationship between Cross-Pollination a
Fruitin
Fruiting conditions of 20 hybrid combinations and 5 fe-
male parents pollinated under natural conditions were
analyzed through variance analysis, applying Duncan
comparison test method, and the data come to the top of
each post. The data presented above indicate that sig-
nificant differences were brought into fruiting rate and
seed-setting rate between hybrid combinations and female
parent. Moreover, much variation appeared in fruiting rate
and seed-setting rate between different hybrids. From
Figure 1 we can see that fruiting condition of chestnut has
been greatly affected by cross-pollination. However, be-
cause affinity among different pollination combinations
vary widely, fruiting conditions of cross-pollin ation trees
may become worse than the trees pollinated under natu-
ral conditions. Such as fruiting rates of combination s A ×
B, D × B, C × D even became significantly lower than
the female parent pollinated under natural condition. So,
appropriate configuration of pollination varieties would
become one of the key measures to improve the yield and
quality of chestnut, while irrational configuration may
even bring the reducti o n of o u t put .
and inverse cross combination were significantly di
each other. Such as fruiting rate of D × B, C × E we
38.91% and 45.02%, while B × D, E × C became 80.87%
and 75.33%; seed-setting rate of E × A was 94.56%, but
A × E only turned out to be 72.24%. Different varieties
could comply with each other well when both fruiting
conditions of cross combination and inverse cross com-
bination go very high. From the second group of Figure 1
we can see Castanea mollissima cv. “Duanci” (E) was re-
garded as the best pollination tree for Castanea mollissima
cv. “Zunyu” (B) with fruiting rate and seed-setting rate
respectively coming to 84.33% and 81.76%; moreover, the
last group of Figure 1 showed the best variety to comply
with Castanea mollissima cv. “Du
tanea mollissima cv. “Zunyu” (B) with fruit
seed-setting rate getting to 79.07% and 85.4
quently, Castanea mollissima cv. “Duanci” (E) and Cas-
tanea mollissima cv. “Zunyu” (B) could comply with
each other quite well for configuration.
4. Discussion
4.1. The Best Configurations for Pollination
Trees
The artificial pollination experiment which has been done
by Renxue Xia and other expert s on chest nut tree i ndi cat e d
that: empty shell rate of self-pollination tree was higher
than that of cross-pollination tree and the number of nut
decreased by 0.74 per shell [10]. Female flower has
strong selectivity on pollen of different vari
ently, to make clear of pollination and fruiting charac-
teristics and appropriate combination of pollination varie-
ties is crucial to improve fruiting condition of chestnut.

Study on Varieties Combination Suitable for Mutual Pollination of Yan Mountain Chestnut 70
Castanea mollissima cv. “Zunyu” (B) was
the best pollination tree for Castanea mollissima cv.
llissima cv. “Zipo” (C)
” (E) complied with each other best.
4.2. Assessment on Relationship between
ntly different between hybrid combina-
ral conditions. So,
ppropriate configuration of pollination varieties would
ecome one of the key measures to improve the yield and
quality of chestnut, while irrational combination may
even bring the reducti o n of o u t put .
4.3. Actual Significance of the Results
One of the main reasons of low yield and low economic
benefit of chestnut has been poor fruiting rate and seed-
setting rate. Hence, more attention should be paid to pol-
lination tree assignment. However, disadvantages such as
no pollination trees, mess of mixed species and low yield
per unit area are standing problems in Zunhua chestnut.
What is more, no study on chestnuts pollination trees has
been done in this region. Therefore, the best configure-
tions above could help local planters avoid low fruiting
rate and seed-setting rate problems. Meanwhile, assess-
ment on relationship between cross-pollination and fruit-
ing conditions highlighted irrational cross-pollination
should be avoided, which corrected the long-terms errors
that all the cross-pollination are beneficial.
All in all, it resolved the pollination tree problem
which would increasingly improve chestnut yield in
Zunhua District
r her painstaking support, encouragement, su-
ience,
Vol. 41, No. 7, 1942, pp. 156-160.
[4] B. W. Fa n and S. J. Luo, “A Study on the Percenta ges of
Fertile Fruit of Different Cross Combinations of Chestnut
Varieties,” Journal of Jiangxi Agricultural University,
Vol. 15, No. 4, 1993, pp. 371-375.
[5] Z. F. Xie, S. C. Zeng and Z. S. Xie, “Study on Selection
of Paternal Cultivars for Nongda No. 1 Chestnut,” Jour-
nal of Nanjing Forestry University (Natural Sciences Edi-
tion), Vol. 29, No. 5, 2005, pp. 94-96.
[6] C. C. Zhao, “Empty Shell Causes and the Pre vention Tech-
niques of Chestnut,” Hebei Fruit s, Vol. 18, No. 4, 2008, p.
52.
[7] M. Y. Yao, “Empty Shell Causes and the Contr ol Measures
of Chestnut,” China Forestry, Vol. 54, No. 9, 2008, p. 62.
[8] W. P. Zhu, “Empty Shell Causes and the Countermea-
sures of Chestnut,” Modern Agricultural Science and
Technology, Vol. 30, No. 17, 2009, p. 119.
[9] Z. F. Xie and J. X. Chen, “Chestnut Cultivation for Early
Fruiting and Fertility,” Guangdong Science and Tech-
nology Press, Guangzhou, 2000.
[10] R. X. Xia and M. T. Ma, “Study on the Forming of
Chestnut Empty-Shell: Factor of the Effect to Empty
Shell from Fertilization,” Journal of Huazhong Agricul-
tural University, Vol. 8, No. 3, 1989, pp. 242-247.
The cross-pollination experiment on 5 chestnut varieties
indicated that:
fut
“Yanhong” (A), Castanea mo and 5. Acknowledgements
This study was supported by Silviculture and Conserva-
tion, Ministry of Education and Hebei
Castanea mollissima cv. “Duanci” (E); Castanea mollis-
sima cv. “Duanci” (E) was regarded as the best pollina-
tion tree for Castanea mollissima cv. “Zunyu” (B); the best
variety to comply with Castanea mollissima cv. “Do ng-
lingmingzhu” (D) was Castanea mollissima cv. “Zunyu”
(B) and Castanea mollissima cv. “Duanci” (E); Castanea
mollissima cv. “Zunyu” (B) and Castanea mollissima cv.
“Duanci
Cross-Pollination and Fruiting Conditions
The results presented here indicated that fruiting condi-
tions were significa
[1]
tions and parents. What is more, fruiting rate, seed-setting
also differ obviously among different hybrids. There- rate
fore cross-pollination influenced fruiting rate, seed-set-
ting rate a lot. What’s more, fruiting conditions may be-
ome worse than that of under natuc
a
b
ure in this area, as well as provided a theoretical basis
for scientific pollination tree assignment for new chestnut
orchard here.
Chestnut Experimental Station. Wang Qian, Zhao Di and
Kou Yanru would like to express profound gratitude to
advisor fo
pervision, and useful suggestions throughout this re-
search.
REFERENCES
Y. H. Zhang, L. Liu and W. J. Liang, “The Fruit Index of
China (Vol. Chestnut, Hazelnut),” China Forestry Press,
Beijing, 2005.
[2] G. G. Jiang, “Early-Yield Cultivation Techniques of
Chestnut,” China Forestry Press, Beijing, 1995.
[3] J. W. MoKay, “Self-Sterility in the Chinese Chestnut,”
Proceedings of the American Society for Floret Sc