Directory UMM :Data Elmu:jurnal:S:Scientia Horticulturae:Vol83.Issue3-4.March2000:
Scientia Horticulturae 83 (2000) 353±362
Response of squash (Cucurbita spp.) as rootstock
for melon (Cucumis melo L.)
Ekaterini Traka-Mavronaa,*, Metaxia Koutsika-Sotirioub,
Theodora Pritsaa
a
National Agricultural Research Foundation (N.AG.RE.F.), Agricultural Research Center of
Macedonia-Thrace, 570 01 Thermi, Thessaloniki, Greece
b
Aristotelian University of Thessaloniki, Department of Agriculture, Laboratory of Genetics and
Plant Breeding, 540 06 Thessaloniki, Greece
Accepted 7 July 1999
Abstract
The effects of different Cucurbita spp. rootstocks on melon cultivars belonging to different
horticultural groups were studied by comparing grafted plants with non-grafted ones under
greenhouse and open ®eld growing conditions. Winter melons (Cucumis melo L.) of the Inodorus
group, cvs. `Thraki', `Peplo' and `Lefko Amynteou', and a summer melon of the Cantalupensis
group, cv. `Kokkini Banana', were used as scions. The commercial hybrids of Cucurbita spp. `TZ148' and `Mamouth' and the landrace of winter squash (C. moschata L.) `Kalkabaki' were used as
rootstocks. The commercial rootstocks were compatible with all scion cultivars tested, while the
landrace was compatible with the three cultivars but with lower survival ratios. Generally,
differences in stem diameter between Cucurbita and Cucumis reduced the survival ratio of grafts.
Fruit yield was not affected by any rootstock. Descriptive and qualitative characteristics of the fruit
of the grafted plants were similar to those of the intact ones, except for taste and texture, which
showed a remarkable deterioration in some of the stock/scion combinations tried. The deterioration
was more severe under protection. However, all Cucurbita spp. rootstocks were found acceptable
for honeydew melons (cv. `Lefko Amynteou'), with C. moschata (cv. `Kalkabaki') being the best.
The landrace of C. moschata is recommended as a source of breeding material for rootstocks of
honeydew melons. # 2000 Elsevier Science B.V. All rights reserved.
Keywords: Cucumis melo; Cucurbita moschata; Cucurbita spp.; Melon; Grafting; Rootstock; Scion
*
Corresponding author. Tel.: 30-31-473433; fax: 30-31-471209.
E-mail address: tpritsa@agro.auth.gr (E. Traka-Mavrona).
0304-4238/00/$ ± see front matter # 2000 Elsevier Science B.V. All rights reserved.
PII: S 0 3 0 4 - 4 2 3 8 ( 9 9 ) 0 0 0 8 8 - 6
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E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
1. Introduction
The wide cultivation of unimproved local populations of melons, combined
with injury by soil-borne diseases (Fusarium wilt., etc.) because of continuous
cropping, resulted in a 20% decrease of the cultivated area in Greece in the last 10
years. Combined breeding programs could be applied to prevent the occurrence of
soil-borne diseases (McCreight et al., 1993). However, breeding new cultivars,
resistant to diseases, is time consuming and enhances the danger of the resistant
cultivars becoming susceptible to new races of pathogens. On the other hand,
grafting onto resistant rootstocks may enable the control of soil-borne diseases
(Lee, 1994; Oda, 1995).
According to Lee (1994) and Oda (1995), grafting is an important technique for
the sustainable production of fruit-bearing vegetables in Korea, Japan, and some
Asian and European countries, where land use is very intensive and continuous
cropping is common. In Greece, grafting is highly popular, especially in southern
areas, where early cropping of watermelons and melons under low tunnels is
practiced. The ratio of the production area using grafted plants to the total
production area, amounts to almost 90±100% for watermelons and 40±50% for
melons in the southern part of Greece. Cucumbers are grafted at a ratio of 5±10%,
while eggplants and tomatoes at 2±3%. In northern Greece, growing grafted fruitbearing vegetables is a rare practice.
Melons of all kinds are grafted to control Fusarium wilt and to increase low
temperature tolerance (Oda, 1995). For this purpose, melons are grafted onto the
same species (Cucumis melo L.), but very rarely onto pumpkin (Cucurbita spp.,
Cucurbita moschata Cucurbita maxima hybrids) and white gourd (Benincasa
hispida) rootstocks, since fruit shape and the taste of plants grafted onto pumpkin,
show a remarkable deterioration. Thus, inter-generic grafting is mainly applied to
oriental melon (Lee, 1994). Generally, the following problems are commonly
associated with grafting and cultivating grafted plants (Lee, 1994; Papadopoulos,
1994; Oda, 1995): Grafting requires time, space, materials and high expertise.
Depending on the combination of scions and rootstocks, graft incompatibility and
a decrease in the quality of fruits may appear. Also, the grafted plants often
require improved cultivation methods and intensive postgraft care. The effects of
rootstocks on fruit quality are often detrimental, except for fruit size, and,
therefore, most newly devised growing recommendations are aimed at
minimizing these effects (Lee, 1994). However, the grafting of vegetables is
extremely popular in many countries, and the demand for successfully grafted
seedlings is growing rapidly in commercial vegetable culture.
Today, a large number of Cucurbita spp. cultivars have been bred and released
as rootstocks for practical use in melon production. In the present study, we
investigated the response of `TZ-148' and `Mamouth', commercial hybrids of
Cucurbita spp., and of the landrace of winter squash (C. moschata L.)
E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
355
`Kalkabaki', as rootstocks for Greek melon cultivars of C. melo L. group
Inodorus and C. melo L. group Cantalupensis. It is the ®rst time that local, well
adapted, cultivars of melons are tried as scions of Cucurbita spp. rootstocks, the
last including an experimental rootstock of a traditional winter squash landrace.
2. Materials and methods
2.1. Plant material
The experiments were conducted in a plastic greenhouse during 1996
(Experiment 1) and in the open ®eld during 1998 (Experiment 2), at the
Agricultural Research Center of Macedonia and Thrace farm, Thessaloniki. The
cultivars used as scions, were `Thraki' and `Kokkini Banana' in Experiment 1 and
`Thraki', `Kokkini Banana', `Peplo' and `Lefko Amynteou' in Experiment 2.
`TZ-148' and `Mamouth' (Geoponiko Spiti, Greece), commercial hybrids of
Cucurbita spp., were used as rootstocks. In Experiment 2, an experimental
rootstock, the winter squash (C. moschata L.) cv. `Kalkabaki', was added.
`Kalkabaki' is a traditional cultivar grown to maturity for use as a sweet pie
ingredient. The fruit has a deep orange ®ne-textured ¯esh, with high sweetness
and taste. It was the ®rst time that it was tried as a rootstock.
The cultivars `Thraki', `Peplo' and `Lefko Amynteou' belong to the C. melo L.
Inodorus group, the winter melons. They are late maturing, with ®rm ¯esh,
usually white or green, sweet, with a cucumber like aroma and are long-keeping.
Traditionally, they are grown in the open ®eld for local consumption or longdistance transport to markets in autumn±winter months. The cultivar `Kokkini
Banana' belongs to the C. melo L. Cantalupensis group, the muskmelon or
cantaloupe. It is adapted to grow early, but has relatively poor shipping and
storage characteristics. The fruit is spherical, deeply ridged, with soft ¯esh
texture, usually white to green, and with a strong aroma.
2.2. Evaluation tests
In Experiment 1, the seeds of scions and rootstocks were sown on 22 and 29
April 1996, respectively, to ensure uniformity in hypocotyl diameter of both the
scion and rootstock. Seedlings were grafted by the tongue approach grafting
(Fig. 1) on 10 May, and the grafted plants were planted on 30 May in a steel and
plastic greenhouse, equipped with shading net. In Experiment 2, seeds of scions
and rootstocks were sown on 2 and 10 April 1998, respectively. The seedlings
were grafted by the same method on 25 April, and were planted in the open ®eld
on 26 May. Grafted plants were hand planted at a 100 cm row spacing, with a 5 m
row length, spaced 50 cm apart, and grown vertically in the greenhouse. In the
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E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
Fig. 1. Grafting procedure adopted.
open ®eld, distances of 150 cm within rows and 200 cm between rows were
applied. Normal cultural practices for each experiment were followed for
irrigation, fertilizer and pesticide application. A randomized complete block
design was adopted with three replications, each consisting of 10 plants. In
detail, the treatments applied with each cultivar were: grafting onto `Kalkabaki',
`TZ-148' and `Mamouth', and an ungrafted control. Experiments were terminated
on 15 September 1996 and 22 September 1998.
The following measurements were recorded: (a) number of plants which
survived until the transplanting date (in Experiment 2); (b) stem diameter at
hypocotyl and ®rst internode of both grafted and non-grafted plants, 25 days after
transplantation (Experiment 1); (c) fruit yield (kg/plant); (d) fruit size (kg/fruit);
(e) fruit shape (Dequatorial/Dpolar); (f) thickness of mesocarp (cm); (g) total
soluble solids (%); (h) ¯esh taste following a 1±5 scale (where 1 very bad,
2 bad, 3 medium, 4 good, 5 very good) and (i) ¯esh texture following a
1±5 scale (where 1 very spongy, 2 spongy, 3 medium, 4 ®ne, 5 very
®ne). Yield measurements were recorded on ripe fruits which were gently handharvested and transported to the laboratory, where they were counted and
weighed. Reported data on descriptive and qualitative characteristics were taken
from 10 fruits of each replication. Calipers were used to measure the polar (Dp)
E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
357
and the equatorial (De) diameter of each fruit. Shape index was calculated by De/
Dp. Each fruit was cut in half along the polar plane, and the thickness of the
mesocarp was measured. Flesh taste and texture were measured in two sections of
the edible tissue, cut from opposite equatorial zones of the halved fruit, and 3±5
tests per section were recorded. The soluble solids were determined with the use
of an Atago PR-100 hand refractometer on the juice taken from the two pieces of
mesocarp tissue, which was cut from opposite equatorial zones of the halved fruit.
2.3. Data analysis
Analyses of variance and tests of signi®cance for all traits were performed to
determine whether there were signi®cant differences among grafted and nongrafted plants of the same cultivar.
3. Results
Survival ratios of melon transplants grafted onto `TZ-148' and `Mamouth'
commercial rootstocks were 42±91% (Fig. 2). The survival ratio of plants grafted
onto `Kalkabaki' rootstock was zero in cv. `Thraki' and 8±52% in cvs. `Lefko
Amynteou', `Kokkini Banana' and `Peplo'.
Stem diameter at the hypocotyl of the two commercial rootstocks was
signi®cantly higher than that of the intact melon cultivars. Thus, it resulted in a
proportional decrease in the quotient of the scion diameter at the ®rst internode to
the rootstock diameter at the hypocotyl (Table 1). The corresponding quotient of
the intact plants (controls) was equal to 1.
Fig. 2. Survival ratio of plants of `Thraki', `Peplo', `Lefko Amynteou' and `Kokkini Banana'
melon cultivars grafted onto `Kalkabaki', `TZ-148' and `Mamouth' rootstocks (Experiment 2).
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E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
Table 1
Stem diameter at hypocotyl and ®rst internode of both grafted and non-grafted plants, 25 days after
transplantation in the greenhouse (Experiment 1)
Treatment
Hypocotyl (D1) (cm)a
1st internode (D2) (cm)a
Quotient (D2/D1)a
Thraki/TZ-148
Thraki/Mamouth
Thraki (control)
K. Banana/TZ-148
K. Banana/Mamouth
K. Banana (control)
1.49
1.52
1.26
1.44
1.34
1.17
1.16 a
1.30 a
1.26 a
1.13 a
1.08 a
1.17a
0.78
0.85
1.00
0.78
0.81
1.00
CV(%)
7
8
5
ab
a
cd
ab
bc
d
b
b
a
b
b
a
a
Same letter indicates the absence of signi®cant differences at p 0.05 by Duncan's multiple
range test.
Fruit yield of all melon cultivars was not signi®cantly affected by grafting onto
`TZ-148' or `Kalkabaki' rootstock (Tables 2 and 3). The use of `Mamouth'
rootstock caused a signi®cant decrease in yield per plant of cv. `Thraki', grown
under greenhouse conditions (Table 2). The mean fruit weight was also not
signi®cantly affected by grafting onto any rootstock (Tables 2 and 3). Similarly,
non-signi®cant differences in fruit shape were found (Tables 2 and 3). The effect
of grafting on the thickness of the mesocarp of fruits, grown under protection,
was not signi®cant (Table 4), while in the open ®eld, the cv. `Thraki' was
favoured by grafting onto `Mamouth' rootstock (Table 5). In the case of soluble
solids (%), a signi®cant difference in open ®eld growing conditions was noticed,
with cv. `Peplo' being inferior after grafting onto `Mamouth' rootstock (Table 5).
The consumer's perception of quality was signi®cantly affected by grafting in
some applied combinations (Tables 4 and 5). Particularly, both fruit taste and
Table 2
Fruit yield (Kg/plant), fruit size (Kg/fruit) and fruit shape (Dequatorial/Dpolar) of grafted and nongrafted plants grown in the greenhouse (Experiment 1)
Treatment
Thraki/TZ-148
Thraki/Mamouth
Thraki (control)
K. Banana/TZ-148
K. Banana/Mamouth
K. Banana (control)
CV(%)
a
Fruit yield (Kg/plant)a
2.69
2.51
3.23
2.41
2.48
2.02
14
ab
b
a
b
b
b
Fruit size (Kg/fruit)a
1.92
1.86
2.39
1.83
2.11
1.69
13
a
a
a
a
a
a
Fruit shape (De/Dp)a
0.92
0.90
0.90
0.96
1.08
0.98
b
b
b
ab
a
ab
6
Same letter indicates the absence of signi®cant differences at p 0.05 by Duncan's multiple
range test.
359
E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
Table 3
Fruit yield (Kg/plant), fruit size (Kg/fruit) and fruit shape (Dequatorial/Dpolar) of grafted and nongrafted plants grown in the open ®eld (Experiment 2)
Treatment
Thraki/Kalkabaki
Thraki/TZ-148
Thraki/Mamouth
Thraki (control)
Peplo/Kalkabaki
Peplo/TZ-148
Peplo/Mamouth
Peplo (control)
L. Amynteou/Kalkabaki
L. Amynteou/TZ-148
L. Amynteou/Mamouth
L. Amynteou (control)
K. Banana/Kalkabaki
K. Banana/TZ-148
K. Banana/Mamouth
K. Banana (control)
CV(%)
Fruit yield (Kg/plant)a
±
4.49
6.26
5.95
2.40
3.52
2.61
3.91
5.47
3.39
3.96
5.69
2.47
3.31
3.00
4.13
Fruit size (Kg/fruit)a
±
1.57
1.82
1.35
0.80
1.28
1.07
1.14
1.74
1.48
1.51
1.57
0.71
1.51
1.62
1.52
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
29
Fruit shape (De/Dp)a
±
0.87
0.91
0.84
0.60
0.59
0.58
0.59
0.90
0.88
0.88
0.90
1.01
1.06
1.03
1.01
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
17
b
b
b
c
c
c
c
b
b
b
b
a
a
a
a
5
a
Same letter indicates the absence of signi®cant differences at p 0.05 by Duncan's multiple
range test.
texture of the grafted melons were inferior compared to those of the plants grown
on their own roots, especially under greenhouse conditions. In open ®eld
conditions, ¯esh texture was signi®cantly affected by grafting in cvs. `Thraki'
Table 4
Thickness (cm), total soluble solids (TSS%), taste and texture of ¯esh of grafted and non-grafted
plants grown in the greenhouse (Experiment 1)
Treatment
Thickness (cm)c
Thraki/TZ-148
Thraki/Mamouth
Thraki (control)
K. Banana/TZ-148
K. Banana/Mamouth
K. Banana (control)
3.77
3.48
4.01
3.78
3.92
3.98
CV(%)
8
a
a
a
a
a
a
a
TSS (%)c
4.98
4.89
5.43
6.11
5.53
5.77
11
a
a
a
a
a
a
Tastea,c
1.97
2.42
3.54
2.20
1.72
3.56
11
b
ab
a
ab
b
a
Textureb,c
3.67
3.80
5.00
3.41
3.69
4.52
bc
bc
a
c
bc
ab
11
Flesh taste, in a scale 1±5 (1 very bad, 2 bad, 3 medium, 4 good, 5 very good).
Flesh texture, in a scale 1±5 (1 very spongy, 2 spongy, 3 medium, 4 ®ne, 5 very
®ne).
c
Same letter indicates the absence of signi®cant differences at p 0.05 by Duncan's multiple
range test.
b
360
E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
Table 5
Thickness (cm), total soluble solids (TSS%), taste and texture of ¯esh of grafted and non-grafted
plants grown in the open ®eld (Experiment 2)
Treatment
Thraki/Kalkabaki
Thraki/TZ-148
Thraki/Mamouth
Thraki (control)
Peplo/Kalkabaki
Peplo/TZ-148
Peplo/Mamouth
Peplo (control)
L. Amynteou/Kalkabaki
L. Amynteou/TZ-148
L. Amynteou/Mamouth
L. Amynteou (control)
K. Banana/Kalkabaki
K. Banana/TZ-148
K. Banana/Mamouth
K. Banana (control)
CV(%)
Thickness (cm)c
±
3.03
3.41
2.57
2.27
2.45
2.27
2.47
2.40
2.56
2.42
2.42
2.77
2.71
2.55
2.61
14
ab
a
bc
c
bc
c
bc
bc
bc
bc
bc
bc
bc
bc
bc
TSS (%)c
±
8.66
8.84
9.87
8.89
9.15
7.85
9.99
10.35
10.02
10.11
10.35
9.72
9.67
9.66
10.29
7
cd
bcd
abc
bcd
abcd
d
abc
a
abc
ab
a
abc
abc
abc
a
Tastea,c
±
1.83
1.83
3.83
2.06
2.49
2.10
3.40
3.90
3.51
3.57
3.99
2.36
3.40
2.96
3.00
21
d
d
a
d
bcd
d
abc
a
abc
ab
a
cd
abc
abcd
abcd
Textureb,c
±
2.13
2.30
4.17
2.22
2.44
2.06
2.80
3.90
3.47
2.86
4.03
2.56
3.63
3.27
3.57
e
de
a
e
de
e
bcde
a
abc
bcde
a
cde
ab
abcd
ab
17
a
Flesh taste, in a scale 1±5 (1 very bad, 2 bad, 3 medium, 4 good, 5 very good).
Flesh texture, in a scale 1±5 (1 very spongy, 2 spongy, 3 medium, 4 ®ne, 5 very
®ne).
c
Same letter indicates the absence of signi®cant differences at p 0.05 by Duncan's multiple
range test.
b
grafted onto `TZ-148' and `Mamouth', `Lefko Amynteou' onto `Mamouth' and
`Kokkini Banana' onto `Kalkabaki'. Flesh taste was affected in cvs. `Thraki'
grafted onto `TZ-148' and `Mamouth', and `Peplo' onto `Kalkabaki' and
`Mamouth'. `Kalkabaki' rootstock contributed to producing fruits of equal quality
to those from intact plants of cv. `Lefko Amynteou'.
4. Discussion
From the results obtained on scion-rootstock compatibility, it was found that
the landrace `Kalkabaki' (C. moschata L.) as rootstock gave a satisfactory
survival ratio of grafts (52%) only in cv. `Lefko Amynteou'. `Thraki' was not
compatible (100% mortality), while cvs. `Kokkini Banana' and `Peplo' survived
at a ratio of 14% and 8%, respectively. Particularly, the leaves of the noncompatible unions turned yellow and cupped, and the plants died. This is a
characteristic of graft-rootstock incompatibility, which contributes to poor
vascular connections that possess connecting sieve tubes, cambium and xylem
E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
361
in the heterografts Cucumis/Cucurbita (Tiedermann, 1989). Even in the case of
`TZ-148' and `Mamouth' commercial rootstocks, the survival ratio of grafts was
high only in cv. `Thraki' (92%). Other cultivars survived at a ratio of 42±83%.
This could be possibly attributed to the differences in stem diameter between
Cucurbita and Cucumis, which reduced the chance of scion vascular bundles
meeting stock bundles, thus resulting in less sites with vascular and phloem
connections. Tiedermann (1989) found different numbers of connecting sieve
tubes between Cucumis/Cucurbita and Cucumis/Cucumis connections because of
differences in stem anatomy, Cucurbita having a large pith cavity.
The results of the effect of the three rootstocks on the agronomic and
qualitative characteristics of the four melon cultivars, allow a series of
considerations on the feasibility of this technique in the cultivars tested. Contrary
to Leoni et al. (1990); Lee (1994) and Oda (1995), there was no clear interaction
between rootstocks and varieties, resulting in a fruit yield enhancement. This
indicates the importance of the rapid development of phloem and xylem
connections, resulting in growth promotion and yield increases.
In agreement with Leoni et al. (1990), fruit descriptive and qualitative
characteristics were not signi®cantly affected by grafting in most combinations
applied. Even the fruit size was not affected, after grafting onto rootstocks with a
vigorous root system. However, in some combinations, deterioration of the
consumer's perception of quality was noticed, mainly with respect to ¯esh taste
and texture. This was more severe under greenhouse conditions, where fertigation
was more ef®cient. Both, `TZ-148' and `Mamouth' Cucurbita spp. commercial
rootstocks caused poor taste and texture in cv. `Thraki' (casaba melons, ovoid
shaped). `Mamouth' and `Kalkabaki' (C. moschata L.) caused a signi®cant
deterioration in taste of cv. `Peplo' (casaba melons, elongated ovoid shaped). All
Cucurbita spp. rootstocks were found suitable for cv. `Lefko Amynteou'
(honeydew melons, spherical shaped), producing fruits of equal taste and texture
to those of the intact plants, with cv. `Kalkabaki' being the best. Both commercial
rootstocks were suitable for `Kokkini Banana' (muskmelons), grown in the open
®eld, but not for the same cultivar under protection. The landrace of C. moschata
caused a remarkable deterioration of texture.
These results, compared with previous information ± which shows that
Cucurbita spp. rootstocks cause a remarkable deterioration in taste of melons,
even though the same cultural treatments, such as fertilizer application and
irrigation, are practiced (Lee, 1994; Oda, 1995) ± indicate that the agents
associated with fruit quality are translocated to the scion through the xylem. This
is the reason why Lee (1994) suggests Cucumis melo is a suitable rootstock for
melon. There are many reports concerning the translocation of agents from
rootstock to scion. Some permanent changes, induced by transmissible agents
from the rootstock, take place in the scion (Ohta and Chuong, 1975; Yagishita et
al., 1985; Dole and Wilkins, 1992). Fusarium-tolerance substances of the stock
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E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
are synthesized in the root and are translocated to the scion through the xylem
(Biles et al., 1989). Sex expression in cucurbitaceous crops may be in¯uenced by
the rootstock (Friedlander et al., 1977; Takahashi et al., 1981). Fruit quality
characteristics, such as fruit shape, skin colour, skin or rind smoothness, ¯esh
texture and color, rind thickness, soluble solids concentration, etc. are in¯uenced
by the rootstock (Lee, 1994). However, honeydew melons (cv. `Lefko
Amynteou') were very well adapted to Cucurbita spp. rootstocks. Additionally,
this cultivar showed the highest survival ratio of grafts onto the landrace of
Cucurbita moschata rootstock, producing fruits of equal quality to that of the
intact plants. The landrace is recommended as a source of breeding material for
rootstocks of honeydew melons.
References
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Friedlander, M., Atamon, D., Galun, E., 1977. The effect of grafting on sex expression in cucumber.
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Lee, J.M., 1994. Cultivation of grafted vegetables. I. Current status, grafting methods, and bene®ts.
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rootstocks on some melon hybrids and a cultivar in greenhouse. Acta Hort. 287, 127±134.
McCreight, J.D., Nerson, H., Grumet, R., 1993. Melon (Cucumis melo L.). In: Kallo, G., Bergh,
B.O. (Eds), Genetic Improvement of Vegetable Crops. Pergamon Press Ltd., pp. 267±283.
Oda, M., 1995. New grafting methods for fruit-bearing vegetables in Japan. Jarq 29, 187±194.
Ohta, Y., Chuong, R.V., 1975. Hereditary changes in Capsicum annuum L. induced by ordinary
grafting. Euphytica 24, 355±368.
Papadopoulos, A., 1994. Growing greenhouse seedless cucumbers in soil and in soilless media.
Agriculture and Agri-Food, Canada, Publication 1902/E, 126 p.
Takahashi, H., Saito, T., Suge, H., 1981. Intergeneria translocation of ¯oral stimulus across a graft
union in monoecious Cucurbitaceae with special reference to the sex expression in cucumber.
Plant and Cell Physiol. 23(1), 1±9.
Tiedermann, R., 1989. Graft union development and symplastic phloem contact in the heterograft
Cucumis sativus on Cucurbita ®cifolia. Plant Physiol. 134(4), 427±440.
Yagishita, S., Hirata, Y., Okochi, J., Kimura, K., Miukami, H., Ohashi, H., 1985. Characterization of
graft-induced change in capsaicin contents of Capsicum annuum L. Euphytica 34, 297±301.
Response of squash (Cucurbita spp.) as rootstock
for melon (Cucumis melo L.)
Ekaterini Traka-Mavronaa,*, Metaxia Koutsika-Sotirioub,
Theodora Pritsaa
a
National Agricultural Research Foundation (N.AG.RE.F.), Agricultural Research Center of
Macedonia-Thrace, 570 01 Thermi, Thessaloniki, Greece
b
Aristotelian University of Thessaloniki, Department of Agriculture, Laboratory of Genetics and
Plant Breeding, 540 06 Thessaloniki, Greece
Accepted 7 July 1999
Abstract
The effects of different Cucurbita spp. rootstocks on melon cultivars belonging to different
horticultural groups were studied by comparing grafted plants with non-grafted ones under
greenhouse and open ®eld growing conditions. Winter melons (Cucumis melo L.) of the Inodorus
group, cvs. `Thraki', `Peplo' and `Lefko Amynteou', and a summer melon of the Cantalupensis
group, cv. `Kokkini Banana', were used as scions. The commercial hybrids of Cucurbita spp. `TZ148' and `Mamouth' and the landrace of winter squash (C. moschata L.) `Kalkabaki' were used as
rootstocks. The commercial rootstocks were compatible with all scion cultivars tested, while the
landrace was compatible with the three cultivars but with lower survival ratios. Generally,
differences in stem diameter between Cucurbita and Cucumis reduced the survival ratio of grafts.
Fruit yield was not affected by any rootstock. Descriptive and qualitative characteristics of the fruit
of the grafted plants were similar to those of the intact ones, except for taste and texture, which
showed a remarkable deterioration in some of the stock/scion combinations tried. The deterioration
was more severe under protection. However, all Cucurbita spp. rootstocks were found acceptable
for honeydew melons (cv. `Lefko Amynteou'), with C. moschata (cv. `Kalkabaki') being the best.
The landrace of C. moschata is recommended as a source of breeding material for rootstocks of
honeydew melons. # 2000 Elsevier Science B.V. All rights reserved.
Keywords: Cucumis melo; Cucurbita moschata; Cucurbita spp.; Melon; Grafting; Rootstock; Scion
*
Corresponding author. Tel.: 30-31-473433; fax: 30-31-471209.
E-mail address: tpritsa@agro.auth.gr (E. Traka-Mavrona).
0304-4238/00/$ ± see front matter # 2000 Elsevier Science B.V. All rights reserved.
PII: S 0 3 0 4 - 4 2 3 8 ( 9 9 ) 0 0 0 8 8 - 6
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E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
1. Introduction
The wide cultivation of unimproved local populations of melons, combined
with injury by soil-borne diseases (Fusarium wilt., etc.) because of continuous
cropping, resulted in a 20% decrease of the cultivated area in Greece in the last 10
years. Combined breeding programs could be applied to prevent the occurrence of
soil-borne diseases (McCreight et al., 1993). However, breeding new cultivars,
resistant to diseases, is time consuming and enhances the danger of the resistant
cultivars becoming susceptible to new races of pathogens. On the other hand,
grafting onto resistant rootstocks may enable the control of soil-borne diseases
(Lee, 1994; Oda, 1995).
According to Lee (1994) and Oda (1995), grafting is an important technique for
the sustainable production of fruit-bearing vegetables in Korea, Japan, and some
Asian and European countries, where land use is very intensive and continuous
cropping is common. In Greece, grafting is highly popular, especially in southern
areas, where early cropping of watermelons and melons under low tunnels is
practiced. The ratio of the production area using grafted plants to the total
production area, amounts to almost 90±100% for watermelons and 40±50% for
melons in the southern part of Greece. Cucumbers are grafted at a ratio of 5±10%,
while eggplants and tomatoes at 2±3%. In northern Greece, growing grafted fruitbearing vegetables is a rare practice.
Melons of all kinds are grafted to control Fusarium wilt and to increase low
temperature tolerance (Oda, 1995). For this purpose, melons are grafted onto the
same species (Cucumis melo L.), but very rarely onto pumpkin (Cucurbita spp.,
Cucurbita moschata Cucurbita maxima hybrids) and white gourd (Benincasa
hispida) rootstocks, since fruit shape and the taste of plants grafted onto pumpkin,
show a remarkable deterioration. Thus, inter-generic grafting is mainly applied to
oriental melon (Lee, 1994). Generally, the following problems are commonly
associated with grafting and cultivating grafted plants (Lee, 1994; Papadopoulos,
1994; Oda, 1995): Grafting requires time, space, materials and high expertise.
Depending on the combination of scions and rootstocks, graft incompatibility and
a decrease in the quality of fruits may appear. Also, the grafted plants often
require improved cultivation methods and intensive postgraft care. The effects of
rootstocks on fruit quality are often detrimental, except for fruit size, and,
therefore, most newly devised growing recommendations are aimed at
minimizing these effects (Lee, 1994). However, the grafting of vegetables is
extremely popular in many countries, and the demand for successfully grafted
seedlings is growing rapidly in commercial vegetable culture.
Today, a large number of Cucurbita spp. cultivars have been bred and released
as rootstocks for practical use in melon production. In the present study, we
investigated the response of `TZ-148' and `Mamouth', commercial hybrids of
Cucurbita spp., and of the landrace of winter squash (C. moschata L.)
E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
355
`Kalkabaki', as rootstocks for Greek melon cultivars of C. melo L. group
Inodorus and C. melo L. group Cantalupensis. It is the ®rst time that local, well
adapted, cultivars of melons are tried as scions of Cucurbita spp. rootstocks, the
last including an experimental rootstock of a traditional winter squash landrace.
2. Materials and methods
2.1. Plant material
The experiments were conducted in a plastic greenhouse during 1996
(Experiment 1) and in the open ®eld during 1998 (Experiment 2), at the
Agricultural Research Center of Macedonia and Thrace farm, Thessaloniki. The
cultivars used as scions, were `Thraki' and `Kokkini Banana' in Experiment 1 and
`Thraki', `Kokkini Banana', `Peplo' and `Lefko Amynteou' in Experiment 2.
`TZ-148' and `Mamouth' (Geoponiko Spiti, Greece), commercial hybrids of
Cucurbita spp., were used as rootstocks. In Experiment 2, an experimental
rootstock, the winter squash (C. moschata L.) cv. `Kalkabaki', was added.
`Kalkabaki' is a traditional cultivar grown to maturity for use as a sweet pie
ingredient. The fruit has a deep orange ®ne-textured ¯esh, with high sweetness
and taste. It was the ®rst time that it was tried as a rootstock.
The cultivars `Thraki', `Peplo' and `Lefko Amynteou' belong to the C. melo L.
Inodorus group, the winter melons. They are late maturing, with ®rm ¯esh,
usually white or green, sweet, with a cucumber like aroma and are long-keeping.
Traditionally, they are grown in the open ®eld for local consumption or longdistance transport to markets in autumn±winter months. The cultivar `Kokkini
Banana' belongs to the C. melo L. Cantalupensis group, the muskmelon or
cantaloupe. It is adapted to grow early, but has relatively poor shipping and
storage characteristics. The fruit is spherical, deeply ridged, with soft ¯esh
texture, usually white to green, and with a strong aroma.
2.2. Evaluation tests
In Experiment 1, the seeds of scions and rootstocks were sown on 22 and 29
April 1996, respectively, to ensure uniformity in hypocotyl diameter of both the
scion and rootstock. Seedlings were grafted by the tongue approach grafting
(Fig. 1) on 10 May, and the grafted plants were planted on 30 May in a steel and
plastic greenhouse, equipped with shading net. In Experiment 2, seeds of scions
and rootstocks were sown on 2 and 10 April 1998, respectively. The seedlings
were grafted by the same method on 25 April, and were planted in the open ®eld
on 26 May. Grafted plants were hand planted at a 100 cm row spacing, with a 5 m
row length, spaced 50 cm apart, and grown vertically in the greenhouse. In the
356
E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
Fig. 1. Grafting procedure adopted.
open ®eld, distances of 150 cm within rows and 200 cm between rows were
applied. Normal cultural practices for each experiment were followed for
irrigation, fertilizer and pesticide application. A randomized complete block
design was adopted with three replications, each consisting of 10 plants. In
detail, the treatments applied with each cultivar were: grafting onto `Kalkabaki',
`TZ-148' and `Mamouth', and an ungrafted control. Experiments were terminated
on 15 September 1996 and 22 September 1998.
The following measurements were recorded: (a) number of plants which
survived until the transplanting date (in Experiment 2); (b) stem diameter at
hypocotyl and ®rst internode of both grafted and non-grafted plants, 25 days after
transplantation (Experiment 1); (c) fruit yield (kg/plant); (d) fruit size (kg/fruit);
(e) fruit shape (Dequatorial/Dpolar); (f) thickness of mesocarp (cm); (g) total
soluble solids (%); (h) ¯esh taste following a 1±5 scale (where 1 very bad,
2 bad, 3 medium, 4 good, 5 very good) and (i) ¯esh texture following a
1±5 scale (where 1 very spongy, 2 spongy, 3 medium, 4 ®ne, 5 very
®ne). Yield measurements were recorded on ripe fruits which were gently handharvested and transported to the laboratory, where they were counted and
weighed. Reported data on descriptive and qualitative characteristics were taken
from 10 fruits of each replication. Calipers were used to measure the polar (Dp)
E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
357
and the equatorial (De) diameter of each fruit. Shape index was calculated by De/
Dp. Each fruit was cut in half along the polar plane, and the thickness of the
mesocarp was measured. Flesh taste and texture were measured in two sections of
the edible tissue, cut from opposite equatorial zones of the halved fruit, and 3±5
tests per section were recorded. The soluble solids were determined with the use
of an Atago PR-100 hand refractometer on the juice taken from the two pieces of
mesocarp tissue, which was cut from opposite equatorial zones of the halved fruit.
2.3. Data analysis
Analyses of variance and tests of signi®cance for all traits were performed to
determine whether there were signi®cant differences among grafted and nongrafted plants of the same cultivar.
3. Results
Survival ratios of melon transplants grafted onto `TZ-148' and `Mamouth'
commercial rootstocks were 42±91% (Fig. 2). The survival ratio of plants grafted
onto `Kalkabaki' rootstock was zero in cv. `Thraki' and 8±52% in cvs. `Lefko
Amynteou', `Kokkini Banana' and `Peplo'.
Stem diameter at the hypocotyl of the two commercial rootstocks was
signi®cantly higher than that of the intact melon cultivars. Thus, it resulted in a
proportional decrease in the quotient of the scion diameter at the ®rst internode to
the rootstock diameter at the hypocotyl (Table 1). The corresponding quotient of
the intact plants (controls) was equal to 1.
Fig. 2. Survival ratio of plants of `Thraki', `Peplo', `Lefko Amynteou' and `Kokkini Banana'
melon cultivars grafted onto `Kalkabaki', `TZ-148' and `Mamouth' rootstocks (Experiment 2).
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E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
Table 1
Stem diameter at hypocotyl and ®rst internode of both grafted and non-grafted plants, 25 days after
transplantation in the greenhouse (Experiment 1)
Treatment
Hypocotyl (D1) (cm)a
1st internode (D2) (cm)a
Quotient (D2/D1)a
Thraki/TZ-148
Thraki/Mamouth
Thraki (control)
K. Banana/TZ-148
K. Banana/Mamouth
K. Banana (control)
1.49
1.52
1.26
1.44
1.34
1.17
1.16 a
1.30 a
1.26 a
1.13 a
1.08 a
1.17a
0.78
0.85
1.00
0.78
0.81
1.00
CV(%)
7
8
5
ab
a
cd
ab
bc
d
b
b
a
b
b
a
a
Same letter indicates the absence of signi®cant differences at p 0.05 by Duncan's multiple
range test.
Fruit yield of all melon cultivars was not signi®cantly affected by grafting onto
`TZ-148' or `Kalkabaki' rootstock (Tables 2 and 3). The use of `Mamouth'
rootstock caused a signi®cant decrease in yield per plant of cv. `Thraki', grown
under greenhouse conditions (Table 2). The mean fruit weight was also not
signi®cantly affected by grafting onto any rootstock (Tables 2 and 3). Similarly,
non-signi®cant differences in fruit shape were found (Tables 2 and 3). The effect
of grafting on the thickness of the mesocarp of fruits, grown under protection,
was not signi®cant (Table 4), while in the open ®eld, the cv. `Thraki' was
favoured by grafting onto `Mamouth' rootstock (Table 5). In the case of soluble
solids (%), a signi®cant difference in open ®eld growing conditions was noticed,
with cv. `Peplo' being inferior after grafting onto `Mamouth' rootstock (Table 5).
The consumer's perception of quality was signi®cantly affected by grafting in
some applied combinations (Tables 4 and 5). Particularly, both fruit taste and
Table 2
Fruit yield (Kg/plant), fruit size (Kg/fruit) and fruit shape (Dequatorial/Dpolar) of grafted and nongrafted plants grown in the greenhouse (Experiment 1)
Treatment
Thraki/TZ-148
Thraki/Mamouth
Thraki (control)
K. Banana/TZ-148
K. Banana/Mamouth
K. Banana (control)
CV(%)
a
Fruit yield (Kg/plant)a
2.69
2.51
3.23
2.41
2.48
2.02
14
ab
b
a
b
b
b
Fruit size (Kg/fruit)a
1.92
1.86
2.39
1.83
2.11
1.69
13
a
a
a
a
a
a
Fruit shape (De/Dp)a
0.92
0.90
0.90
0.96
1.08
0.98
b
b
b
ab
a
ab
6
Same letter indicates the absence of signi®cant differences at p 0.05 by Duncan's multiple
range test.
359
E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
Table 3
Fruit yield (Kg/plant), fruit size (Kg/fruit) and fruit shape (Dequatorial/Dpolar) of grafted and nongrafted plants grown in the open ®eld (Experiment 2)
Treatment
Thraki/Kalkabaki
Thraki/TZ-148
Thraki/Mamouth
Thraki (control)
Peplo/Kalkabaki
Peplo/TZ-148
Peplo/Mamouth
Peplo (control)
L. Amynteou/Kalkabaki
L. Amynteou/TZ-148
L. Amynteou/Mamouth
L. Amynteou (control)
K. Banana/Kalkabaki
K. Banana/TZ-148
K. Banana/Mamouth
K. Banana (control)
CV(%)
Fruit yield (Kg/plant)a
±
4.49
6.26
5.95
2.40
3.52
2.61
3.91
5.47
3.39
3.96
5.69
2.47
3.31
3.00
4.13
Fruit size (Kg/fruit)a
±
1.57
1.82
1.35
0.80
1.28
1.07
1.14
1.74
1.48
1.51
1.57
0.71
1.51
1.62
1.52
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
29
Fruit shape (De/Dp)a
±
0.87
0.91
0.84
0.60
0.59
0.58
0.59
0.90
0.88
0.88
0.90
1.01
1.06
1.03
1.01
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
17
b
b
b
c
c
c
c
b
b
b
b
a
a
a
a
5
a
Same letter indicates the absence of signi®cant differences at p 0.05 by Duncan's multiple
range test.
texture of the grafted melons were inferior compared to those of the plants grown
on their own roots, especially under greenhouse conditions. In open ®eld
conditions, ¯esh texture was signi®cantly affected by grafting in cvs. `Thraki'
Table 4
Thickness (cm), total soluble solids (TSS%), taste and texture of ¯esh of grafted and non-grafted
plants grown in the greenhouse (Experiment 1)
Treatment
Thickness (cm)c
Thraki/TZ-148
Thraki/Mamouth
Thraki (control)
K. Banana/TZ-148
K. Banana/Mamouth
K. Banana (control)
3.77
3.48
4.01
3.78
3.92
3.98
CV(%)
8
a
a
a
a
a
a
a
TSS (%)c
4.98
4.89
5.43
6.11
5.53
5.77
11
a
a
a
a
a
a
Tastea,c
1.97
2.42
3.54
2.20
1.72
3.56
11
b
ab
a
ab
b
a
Textureb,c
3.67
3.80
5.00
3.41
3.69
4.52
bc
bc
a
c
bc
ab
11
Flesh taste, in a scale 1±5 (1 very bad, 2 bad, 3 medium, 4 good, 5 very good).
Flesh texture, in a scale 1±5 (1 very spongy, 2 spongy, 3 medium, 4 ®ne, 5 very
®ne).
c
Same letter indicates the absence of signi®cant differences at p 0.05 by Duncan's multiple
range test.
b
360
E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
Table 5
Thickness (cm), total soluble solids (TSS%), taste and texture of ¯esh of grafted and non-grafted
plants grown in the open ®eld (Experiment 2)
Treatment
Thraki/Kalkabaki
Thraki/TZ-148
Thraki/Mamouth
Thraki (control)
Peplo/Kalkabaki
Peplo/TZ-148
Peplo/Mamouth
Peplo (control)
L. Amynteou/Kalkabaki
L. Amynteou/TZ-148
L. Amynteou/Mamouth
L. Amynteou (control)
K. Banana/Kalkabaki
K. Banana/TZ-148
K. Banana/Mamouth
K. Banana (control)
CV(%)
Thickness (cm)c
±
3.03
3.41
2.57
2.27
2.45
2.27
2.47
2.40
2.56
2.42
2.42
2.77
2.71
2.55
2.61
14
ab
a
bc
c
bc
c
bc
bc
bc
bc
bc
bc
bc
bc
bc
TSS (%)c
±
8.66
8.84
9.87
8.89
9.15
7.85
9.99
10.35
10.02
10.11
10.35
9.72
9.67
9.66
10.29
7
cd
bcd
abc
bcd
abcd
d
abc
a
abc
ab
a
abc
abc
abc
a
Tastea,c
±
1.83
1.83
3.83
2.06
2.49
2.10
3.40
3.90
3.51
3.57
3.99
2.36
3.40
2.96
3.00
21
d
d
a
d
bcd
d
abc
a
abc
ab
a
cd
abc
abcd
abcd
Textureb,c
±
2.13
2.30
4.17
2.22
2.44
2.06
2.80
3.90
3.47
2.86
4.03
2.56
3.63
3.27
3.57
e
de
a
e
de
e
bcde
a
abc
bcde
a
cde
ab
abcd
ab
17
a
Flesh taste, in a scale 1±5 (1 very bad, 2 bad, 3 medium, 4 good, 5 very good).
Flesh texture, in a scale 1±5 (1 very spongy, 2 spongy, 3 medium, 4 ®ne, 5 very
®ne).
c
Same letter indicates the absence of signi®cant differences at p 0.05 by Duncan's multiple
range test.
b
grafted onto `TZ-148' and `Mamouth', `Lefko Amynteou' onto `Mamouth' and
`Kokkini Banana' onto `Kalkabaki'. Flesh taste was affected in cvs. `Thraki'
grafted onto `TZ-148' and `Mamouth', and `Peplo' onto `Kalkabaki' and
`Mamouth'. `Kalkabaki' rootstock contributed to producing fruits of equal quality
to those from intact plants of cv. `Lefko Amynteou'.
4. Discussion
From the results obtained on scion-rootstock compatibility, it was found that
the landrace `Kalkabaki' (C. moschata L.) as rootstock gave a satisfactory
survival ratio of grafts (52%) only in cv. `Lefko Amynteou'. `Thraki' was not
compatible (100% mortality), while cvs. `Kokkini Banana' and `Peplo' survived
at a ratio of 14% and 8%, respectively. Particularly, the leaves of the noncompatible unions turned yellow and cupped, and the plants died. This is a
characteristic of graft-rootstock incompatibility, which contributes to poor
vascular connections that possess connecting sieve tubes, cambium and xylem
E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
361
in the heterografts Cucumis/Cucurbita (Tiedermann, 1989). Even in the case of
`TZ-148' and `Mamouth' commercial rootstocks, the survival ratio of grafts was
high only in cv. `Thraki' (92%). Other cultivars survived at a ratio of 42±83%.
This could be possibly attributed to the differences in stem diameter between
Cucurbita and Cucumis, which reduced the chance of scion vascular bundles
meeting stock bundles, thus resulting in less sites with vascular and phloem
connections. Tiedermann (1989) found different numbers of connecting sieve
tubes between Cucumis/Cucurbita and Cucumis/Cucumis connections because of
differences in stem anatomy, Cucurbita having a large pith cavity.
The results of the effect of the three rootstocks on the agronomic and
qualitative characteristics of the four melon cultivars, allow a series of
considerations on the feasibility of this technique in the cultivars tested. Contrary
to Leoni et al. (1990); Lee (1994) and Oda (1995), there was no clear interaction
between rootstocks and varieties, resulting in a fruit yield enhancement. This
indicates the importance of the rapid development of phloem and xylem
connections, resulting in growth promotion and yield increases.
In agreement with Leoni et al. (1990), fruit descriptive and qualitative
characteristics were not signi®cantly affected by grafting in most combinations
applied. Even the fruit size was not affected, after grafting onto rootstocks with a
vigorous root system. However, in some combinations, deterioration of the
consumer's perception of quality was noticed, mainly with respect to ¯esh taste
and texture. This was more severe under greenhouse conditions, where fertigation
was more ef®cient. Both, `TZ-148' and `Mamouth' Cucurbita spp. commercial
rootstocks caused poor taste and texture in cv. `Thraki' (casaba melons, ovoid
shaped). `Mamouth' and `Kalkabaki' (C. moschata L.) caused a signi®cant
deterioration in taste of cv. `Peplo' (casaba melons, elongated ovoid shaped). All
Cucurbita spp. rootstocks were found suitable for cv. `Lefko Amynteou'
(honeydew melons, spherical shaped), producing fruits of equal taste and texture
to those of the intact plants, with cv. `Kalkabaki' being the best. Both commercial
rootstocks were suitable for `Kokkini Banana' (muskmelons), grown in the open
®eld, but not for the same cultivar under protection. The landrace of C. moschata
caused a remarkable deterioration of texture.
These results, compared with previous information ± which shows that
Cucurbita spp. rootstocks cause a remarkable deterioration in taste of melons,
even though the same cultural treatments, such as fertilizer application and
irrigation, are practiced (Lee, 1994; Oda, 1995) ± indicate that the agents
associated with fruit quality are translocated to the scion through the xylem. This
is the reason why Lee (1994) suggests Cucumis melo is a suitable rootstock for
melon. There are many reports concerning the translocation of agents from
rootstock to scion. Some permanent changes, induced by transmissible agents
from the rootstock, take place in the scion (Ohta and Chuong, 1975; Yagishita et
al., 1985; Dole and Wilkins, 1992). Fusarium-tolerance substances of the stock
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E. Traka-Mavrona et al. / Scientia Horticulturae 83 (2000) 353±362
are synthesized in the root and are translocated to the scion through the xylem
(Biles et al., 1989). Sex expression in cucurbitaceous crops may be in¯uenced by
the rootstock (Friedlander et al., 1977; Takahashi et al., 1981). Fruit quality
characteristics, such as fruit shape, skin colour, skin or rind smoothness, ¯esh
texture and color, rind thickness, soluble solids concentration, etc. are in¯uenced
by the rootstock (Lee, 1994). However, honeydew melons (cv. `Lefko
Amynteou') were very well adapted to Cucurbita spp. rootstocks. Additionally,
this cultivar showed the highest survival ratio of grafts onto the landrace of
Cucurbita moschata rootstock, producing fruits of equal quality to that of the
intact plants. The landrace is recommended as a source of breeding material for
rootstocks of honeydew melons.
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