*Corresponding author email: lodam000agricos@gail.c
Cucumber (Cucumis sativus L.) is one of the
most important and popular cucurbitaceous
vegetable crops grown extensively throughout the
tropical and subtropical region of the world.
According to De Candle (1967), India is consider as
a centre of origin of cucumber. It is grown commonly
throughout India and popularly known as Kakari
(Gujarati). The fruits are edible and very much used
as salad and used during summer as a cooling
food. Fruit is demulcent while seeds are cooling,
tonic, diuretic and anthelintic when leaves along with
cumin seeds administered (Vashista, 1974). High
degree of cross-pollination, wide range of genetic
variability in vegetative and fruit characters exist in
this crop. Concerted efforts towards its improvement
and developing new varieties are lacking and only a
few improved varieties have been developed. Thus,
it necessitates development of high yielding, better
quality varieties through efficient breeding
programmes. The success of any breeding
procedure is determined by useful gene
combination organized in the form of high combining
inbreds and heterosis in their crosses. The line x
tester analysis was adopted in the present study on
cucumber to gather information on the magnitude
of heterosis, general and specific combining abilities
and various types of gene effects involved for different
quantitative characters.
Material and Methods
An experiment was conducted during Kharif 2009
at the Experimental farm, N. M. College of Agriculture,
Navsari Agricultural University, Navsari. The
Heterosis and Combining Ability in Cucumber
(Cucumis sativus L.)
P.N. Mule, V. Khandelwal, V.A. Lodam*, D.A. Shinde, P.P. Patil and A.B. Patil
Department of Genetics and Plant Breeding,
Navsari Agricultural University, Navsari - 396 450
The present study on heterosis and combining ability for fruit yield and its components was
carried out in a set of 27 F1 hybrids of cucumber obtained from a Line x Tester method
involving twelve diverse parents at Navsari Agricultural University, Navsari 2009. The ratio of
the genetic variance was less than unity, which indicated the predominance of the non-
additive gene action in all the traits. The analysis revealed that none of the parents was found
good general combiners for all the traits consistently, however parents CCP-9, Gujarat local
and SPP-44 were good combiner for fruit yield and its contributing traits. The hybrids Pilibhit
Local x K-90 followed by Sheetal x SPP-44 and Sheetal x CC-9 have exhibited higher
heterobeltiosis for fruit yield and its components characters. These crosses involved poor
x poor and poor x good combiner parents. Further improvement in fruit yield could be possible
through the hybridization and selection in transgressive segregants.
Keys words: Heterosis, combining ability, gene action, Cucumis sativus L., line x tester
experimental materials comprised of 3 lines
(females) namely; Sheetal (L1), Gujarat Local (L2)
and Pilibhit Local (L3) and nine testers (males)
namely; SPP-44 (T1), K-90 (T2), CV-5 (T3), SPP-93
(T4), CC-9 (T5), SPP-63 (T6), DC-2 (T7), PCUC-8
(T8) and PCUC-28 (T9) and Gujarat Local-1 as an
standard check. The complete set of 27 F1s and 12
parents were grown in randomized block design
(RBD) with replications. Row to row and plant to
plant spacing were maintained at 3 m and 2 m,
respectively. All the recommended agronomic
package of practices was followed to grow a healthy
crop. In each replication, 5 plants and F1s were
marked for observation. Observations were
recorded on nine important characters, viz. node
number on which first male flower appeared, node
number on which first female flower appeared,
average fruit length (cm), average fruit diameter (cm),
number of lateral branches per vine, number of fruits
per vine, length of vine and fruit yield per vine (kg).
Combining ability analysis was done by using Model
l and Method ll of Griffing (1956). Heterosis was
calculated as the percentage of F1 performance in
the favorable direction of its better parent as
suggested by Hayes et al. (1955).
Results and Discussion
The mean sum of square due to gca and sca
were highly significant for all nine characters except
node number on which first male flower appeared,
node number on which first female flower appeared,
number of lateral branches and fruit diameter for
gca variance (Table 1). It indicated that both additive
and non-additive gene action were involved in the
421
expression of these traits. Similar results have been
reported by Prajapati (2008) and Prasad and Singh,
(1992) in cucumber. The estimates of sca variance
(σσσσσ2 sca) was higher than gca variance (σσσσσ2 gca). The
ratio of gca/sca variance (σσσσσ2 gca/σσσσσ2 sca) being lesser
than unity for all the nine traits revealed
preponderance of non additive gene effects in the
inheritance of fruit yield and its components traits.
The present findings are in congruence with the
reports of Solanki and Shah (1990), Ananthan and
Pappiah (1997), Sarkar and Sirohi (2006) in
cucumber.
The estimates of gca effects (Table 2) revealed
that the none of the parents exhibited good gca for
all the characters so it was difficult to pick good
combiners for all the characters together because
the combining ability effects were not consistent for
all the yield components, possibly because of
negative association among of the characters
(Solanki and Shah, 1990). This shows that genes
for different desirable characters would have to be
combined from different sources (Nehe et al. 2007).
Among the twelve parents, CC-9, Gujarat local and
SSP-44 were good general combiner for fruit yield
Table 1. Analysis of variance for combining ability for different characters in cucumber
Source of variation
NFM
NFF
NLB
FL
FD
AFW
VL
NFP
FYV
σσσσσ2 gca
-0.019
0.010
0.036
1.361**
-0.018
37.698*
38.966*
1.942**
0.139**
σσσσσ2 sca
0.164**
0.481**
0.575**
1.912**
0.490*
267.515**
103.94**
4.985**
0.191**
σσσσσ2 gca σσσσσ2 sca
-1.158
0.020
0.062
0.711
-0.036
0.140
0.384
0.389
0..727
NFM = Node number on which first male flower appeared, NFF= Node number on which first female flower appeared, NLB = Number of lateral branches per vine , F =Fruit length (cm), FD
= Fruit diameter (cm), AFW = Average fruit weight (g), VL = Vine length (cm), NFP = Number of fruit per vine, FYV = Fruit yield per vine (kg).
Parents
NFM
NFF
NLB
FL
FD
AFW
VL
NFP
FYV
Females
Sheetal
-0.059
0.178
0.185
-0.851**
-0.014
-3.655
-1.020
0.265
0.126
Gujarat local
-0.013
-0.290*
0.222
1.280**
0.271*
10.264**
8.640**
1.562**
0.381**
Pilibhit local
0.072
0.112
-0.407**
-0.429*
-0.257*
-6.609**
-7.619**
-1.827**
-0.507*
SPP-44
-0.337*
-0.807**
0.519*
3.065**
0.600**
19.394**
-6.453
2.006**
0.380**
K-90
0.049
0.313
0.074
1.052**
-0.006
5.816
-10.283*
-0.772
0.211
CV-5
-0.193
0.309
-0.593**
-1.224**
-0.397*
-12.984**
6.594
-1.216**
-0.107
SPP-93
0.250
0.050
0.407
-0.189
-0.102
-4.551
-8.819
0.106
-0.112
CC-9
-0.177
-0.843**
0.630*
1.442**
0.372
10.849**
1.440
2.784**
0.506**
SPP-63
0.230
0.105
-0.481*
-2.157**
-0.255
-0.173
3.263
-0.994*
-0.229
DC-2
0.114
0.535*
0.185
-1.746**
-0.080
-11.64**
5.228
-0.549
-0.334**
PCUC-8
0.280*
0.572*
-0.815**
-1.319**
-0.360
-3.720
-5.383
-2.372**
-0.462**
PCUC-28
-0.215
-0.190
0.074*
1.076**
0.227
-2.970
10.414**
1.006*
0.147
Table 2. Estimation of general combining ability (gca) effects of parents for different characters in
Cucumber
per vine. These parents also showed significant
general combining ability effects in desirable
direction for various characters, CC-9 for node
number on which first female flower appeared, days
to 50 per cent flowering (female), fruit length, average
fruit weight and number of fruit per vine, while
Gujarat local for node number on which first female
flower appeared, fruit length, fruit diameter, average
fruit weight, vine length and number of fruit per vine
and SSP-44 for node number on which first male
flower appeared, node number on which first female
flower appeared, number of lateral branches per
vine, fruit length, fruit diameter, average fruit weight
and number of fruit per vine. These parents were
superior for most of the traits, an inter mating
population involving all possible crosses among
themselves subjected to biparental mating in early
generation will be expected to offer the maximum
promise in breeding for yield and earliness. Similar
results reported by Nehe et al. (2007) in cucumber
and Niyaria and Bhalala (2001) in ridge gourd.
The estimates of specific combining ability
effects were found negatively significant in cross
combinations Pilibhit Local x K-90 (-0.83) and
Gujarat Local x DC-2 (-0.50) for Node number on
which first male flower appeared, Pilibhit Local x K-
90 (-1.17), Gujarat Local x SPP-93 (-1.14) and
Gujarat Local x PCUC-28 (-0.87) for node number
on which first female flower appeared. The highest
significantly positive specific combining ability effect
in Gujarat Local x PCUC-28 (1.22) for number of
lateral branches per vine, Pilibhit Local x K-90 (2.55)
for Fruit length, Pilibhit Local x K-90 (1.30) for Fruit
diameter, Pilibhit Local x K-90 (25.92) for average
fruit weight, Pilibhit Local x SPP-63 (21.99) for vine
length, Pilibhit Local x K-90 (4.38) for number of
fruits per vine. Hybrids viz., Pilibhit Local x K-90,
Sheetal x SPP-44 and Sheetal x CC-9 produced the
highest sca effect for the fruit yield per vine (Table 3).
Thus, sca effect of these three crosses indicates
the inclusion of atleast one good combining parent
in producing superior hybrids. However, a former
cross involved both of the parents with poor
combining abilities. This suggests that high sca
effect of any cross combination does not necessarily
422
Table 3. Estimation of specific combining ability (sca) effects of hybrids for various characters in cucumber
Crosses
NFM
NFF
NLB
FL
FD
AFW
VL
NFP
FYV
Sheetal x SPP-44
-0.22
-0.69
0.91*
-0.13
0.74*
19.01**
5.77
2.50**
0.40*
Sheetal x K-90
0.33
0.16
-0.40
-0.77
-0.47
-4.43
-12.20
-0.71
-0.43*
Sheetal x CV-5
0.32
-0.13
0.25
-0.05
0.21
10.13
-6.20
-0.93
-0.08
Sheetal x SPP-93
-0.19
0.83*
-1.07*
-0.28
-0.79*
-18.86**
4.61
-0.25
-0.09
Sheetal x CC-9
-0.53*
0.96*
0.37
1.23*
1.23**
15.99**
-3.48
0.73
0.57*
Sheetal x SPP-63
0.24
0.18
-0.18
0.51
-0.24
11.05
-6.83
-0.15
0.07
Sheetal x DC-2
0.11
0.13
1.14**
0.41
0.89*
-0.13
6.32
-0.93
0.079
Sheetal x PCUC-8
-0.25
-0.51
0.14
-0.16
-0.19
0.04
5.62
1.55
0.30
Sheetal x PCUC-28
0.03
0.56
-0.74
-0.75
-0.27
-21.17**
6.37
-1.82*
-0.40
Gujarat Local x SPP-44
-0.31
-0.34
0.44
2.06**
0.23
2.80
-5.67
0.88
0.23
Gujarat Local x K-90
0.50*
1.00*
-0.44
-1.78**
-0.82*
-21.48**
6.21
-3.67**
-0.38
Gujarat Local x CV-5
-0.33
0.53
-0.44
-0.17
-0.43
-23.08**
-14.85
-0.22
-0.20
Gujarat Local x SPP-93
0.50*
-1.14**
0.88*
1.06
1.06**
18.44**
3.45
3.11**
-0.50*
Gujarat Local x CC-9
0.30
-0.30
0.33
0.80
0.46
9.28
13.02
0.43
-0.01
Gujarat Local x SPP-63
0.20
0.20
-0.88*
-1.37*
-0.41
-9.09
-15.16
0.21
-0.11
Gujarat Local x DC-2
-0.50*
0.51
-0.88*
-1.19*
-0.77*
4.84
7.86
-0.89
0.09
Gujarat Local x PCUC-8
0.07
0.41
-0.22
-0.65
-0.02
-0.20
6.31
-1.40
-0.41*
Gujarat Local x PCUC-28
-0.43
-0.87*
1.22**
1.25*
0.70*
18.50**
-1.18
1.54
0.30
Pilibhit Local x SPP-44
0.53*
1.04*
-0.92*
-1.92**
-0.78*
-10.19
-0.10
-3.39
-0.64**
Pilibhit Local x K-90
-0.83**
-1.17**
0.85*
2.55**
1.30**
25.92**
5.99
4.38**
0.82**
depend on the gca effects of the parental lines
involved. This superiority of sca effects may be due
to complementary type of gene action or involvement
of non allelic interaction of fixable and non fixable
genetic variance (Patel and Desai, 2008 and
Purohit, 2007).
The hybrids varied in magnitude and direction of
heterosis for most of the characters (Table 4). The
significant heterobeltiosis observed for node
number on which first male flower appeared in cross
combination viz., Gujarat Local x PCUC-28 (-32.43)
and Gujarat Local x SPP-44 (29.25), node number
Pilibhit Local x CV-5
0.07
-0.39
0.18
0.22
0.22
12.95*
21.06*
1.16
0.28
Pilibhit Local x SPP-93
-0.31
0.30
0.18
-0.77
-0.27
0.42
-8.07
-2.86**
-0.40*
Pilibhit Local x CC-9
0.08
0.83*
-0.70
-2.03**
-0.77*
-25.28**
-9.54
-1.17
-0.19
Pilibhit Local x SPP-63
-0.44
-0.38
1.07*
0.86
0.65
-1.95
21.99**
-0.06
0.10
Pilibhit Local x DC-2
0.38
-0.64
-0.25
0.78
-0.12
-4.70
-14.19
1.82*
-0.17
Pilibhit Local x PCUC-8
0.18
0.09
0.07
0.82
0.22
0.16
-11.94
-0.15
0.10
Pilibhit Local x PCUC-28
0.40
0.31
-0.48
-0.50
-0.43
2.67
-5.19
0.27
0.09
Table 4. The better performing F1 over better parent for different characters in cucumber
Node number on which first male
2
Gujarat Local x PCUC-28 (-32.43) ,Gujarat Local x SPP-44 (29.25)
flower appeared
Node number on which first female
7
Gujarat Local x SPP-44 (-30.06), Gujarat Local x CC-9 (-29.94), Gujarat
flower appeared
Local x SPP-93 (-29.72)
Number of lateral branches per vine
3
Sheetal x DC-2 (41.67), Sheetal x SPP-44 (33.33), Gujarat Local x SPP-93
(30.77)
Fruit length
5
Sheetal x SPP-44 (22.35), Pilibhit Local x K-90 (15.89), Pilibhit Local x
SPP-44 (11.61)
Fruit diameter
6
Sheetal x SPP-44 (35.94), Sheetal x CC-9 (23.08), Gujarat Local x SPP-93
(22.07)
Average fruit weight
7
Pilibhit Local x K-90 (22.68), Gujarat Local x SPP-44(18.83), Sheetal x CC-
9 (18.61)
Vine length
5
Pilibhit Local x SPP-63 (21.35), Pilibhit Local x CV-5 (20.46), Gujarat Local
x CC-9 (18.33)
Number of fruit per vine
8
Sheetal x SPP-44 (66.67), Sheetal x CC-9 (75.00), Pilibhit Local x K-90
(33.33)
Fruit yield per vine
7
Pilibhit Local x K-90 (57.96), Sheetal x SPP-44 (56.60), Sheetal x CC-9
(53.89)
Three best cross combination with
heterosis value (%)
Characters
No. of crosses with
significant heterosis
on which first female flower appeared in Gujarat
Local x SPP-44 (-30.06), Gujarat Local x CC-9 (-
29.94), Gujarat Local x SPP-93 (-29.72), Sheetal x
SPP-44 (-28.85), Sheetal x CC-9 (-26.79), Gujarat
Local x PCUC-28 (-24.57) and Pilibhit Local x K-90
(-20.87). In general, heterosis for node number on
which first male flower appeared and node number
on which first female flower appeared should be in
negative direction, in order to develop early cultivars
therefore, Gujarat Local x SPP-44 can be used in
future crop improvment programme for development
for early fruit bearing hybrids. These findings are in
423
consonance with Prajapati, (2008), Patel and Desai
(2008). The character that contribute to vegetative
growth such as number of lateral branches per vine
expressed highest magnitude of heterosis in cross
combinations viz., Sheetal x DC-2 (41.67), Sheetal
x SPP-44 (33.33) and Gujarat Local x SPP-93
(30.77). Cross combinations viz., Pilibhit Local x
SPP-63 (21.35), Pilibhit Local x CV-5 (20.46) and
Gujarat Local x CC-9 (18.33) expressed positively
significant heterosis for vine length. Above findings
are in accordance with the results reported by
Prajapati, (2008) and Prasad and Singh (1992).
A desirable degree of vegetative growth is
essential for realizing high fruit yield. Regarding the
fruit length, five crosses expressed positively
significant heterosis over heterobeltiosis in cross
combination Pilibhit Local x SPP-63 (21.35), Pilibhit
Local x CV-5 (20.46) and Gujarat Local x CC-9
(18.33). However, the cross combinations namely
Sheetal x SPP-44 (35.94), Sheetal x CC-9 (23.08)
and Gujarat Local x SPP-93 (22.07) have recorded
higher heterosis for fruit diameter. For average fruit
weight the crosses viz., Pilibhit Local x K-90 (22.68),
Gujarat Local x SPP-44(18.83) and Sheetal x CC-9
(18.61) showed higher heterosis. These reports are
similarly Randhawa and Singh (1990) and Rao et
al. (2000).
Fruit characters directly played important role in
the enhancement of the yield. Cross combinations
viz., Sheetal x SPP-44 (66.67), Sheetal x CC-9
(75.00) and Pilibhit Local x K-90 (33.33) exhibited
the highest heterobeltiosis for the number of fruit
per vine. The results are in close conformity with
findings of Prajapati, (2008) and Prasad and Singh
(1992). Number of fruit per vine had direct correlation
with fruit yield per vine (Ananthan and Pappiah,
1997). The extent of heterosis for fruit yield per vine
varied greatly. The highest value of heterosis was
observed in Pilibhit Local x K-90 (57.96) followed by
Sheetal x SPP-44 (56.60) and Sheetal x CC-9
(53.89). These crosses showing desirable heterosis
for fruit yield per vine in addition to most of the yield
contributing characters studied. Thus, total yield
could be the result of combinational heterosis (Das
and Rai, 1972). Similar results were reported by
Prajapati, (2008), Bairagi, et al. (2002) and Hormuzidi
and More (1989).
Considering the overall performance in respect
of fruit yield per vine, most promising three hybrids
viz., Pilibhit Local x K-90, Sheetal x SPP-44 and
Sheetal x CC-9 exhibited high heterotic effects.
These crosses have higher sca effects due to
involvement of poor x poor and poor x good parents.
The higher sca effect observed in poor x poor general
combiners cross might be due to non-additive gene
effects and such could be exploited through the
hybridization, which is possible in the crop due to
monocieous nature of flowers. The cross involved
poor x good general combiners can produce good
transgressive segregants in later generation.
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Received: September 19, 2011; Revised: March 21, 2012; Accepted: June 4, 2012