Cucurbitaceae '96/EUCARPIA VI
"Cucurbits Towards 2000"
Genetics & Breeding
The Effects of Season and Irradiation Doses on Haploid Embryo Production in Cucumber (Cucumis sativus L.)
G. Çaglar1 and K. Abak2
1Horticultural Research Institute, Erdemli, Icel, Turkey, and
2Department of Horticulture, Faculty of Agriculture, University
of Cukurova, Adana, Turkey
The effects of season and the doses of 300, 450 and 600 Gy gamma
irradiation on in situ parthenogenetic haploid embryo
induction in cucumber genotypes were investigated. Two gynoic
hybrids (Gamar F1 and Seraset F1) and two
local open pollinated cultivars (Dere and Gengelkoy) were used.
We obtained many fruits, seeds and embryos from the four
genotypes with pollination by irradiated pollen. However, the
season and irradiation does significantly affect the haploid
embryo yield. The best season was between May and September.
The maximum values were reached in June (4.52 embryo/fruit) and
in July (8.00 embryo/fruit) with the use of gamma-300 dose. The
300 Gy dose led to the highest embryo production with means of
1.66 and 2.66 embryos per fruit in two consecutive years.
Interspecific Hybridization of Cucumis sativus x
Cucumis melo, as a Potential Way to Transfer
Resistance to Pseudoperonospora cubensis
A. Lebeda1, E. Krístková2
and M. Kubaláková3
1Palacký University, Faculty of Natural
Sciences, Department of Botany, 772 36 Olomouc-Holice, Czech
Republic, 2Research Institute of Crop Production,
Praha; Gene Bank Division, 772 36 Olomouc-Holice, Czech
Republic, and 3De Montfort University, Norman
Borlaug Institute for Plant Science; Institute of
Experimental Botany, Academy of Sciences of the Czech
Republic, SokolovskA 6, 772 00 Olomouc, Czech Republic
Abstract. The aim of this work was to transfer
resistance to cucumber downy mildew (Pseudoperonospora
cubensis) from Cucumis melo to Cucumis
sativus. The attempt of overcoming the crossing
barriers resulting from different chromosome number of both
species was based on the combination of two techniques -
classic pollination of intact Cucumis sativus plants
by the pollen of C. melo followed by cultivation of
excised young seeds and embryos in vitro.
In the period 1992-1994, a set of C. sativus cvs.
Zidovická produkta, Marketmore, Bílské,
Melnické and Alert F1 and breeding lines SM-
6022, SM-6514, SM-6511, and SM-6026 were pollinated by C.
melo genotypes M 320 'Nantais oblong', M 323 (PMR 5
line), MR 1, PI 124112, PI 124111 and PI 200819 In four
cycles. During pollination, the biologically active
substances (IBA, 2,4D, BAP, 4CPA, AgNO3 and
glycine) in lanolin paste were applied on the cucumber
flower stem or stigma to promote better development of
fruits, seeds and embryos. Ten to twenty days after
pollination, the hybrid fruits were picked, measured and
examined for the presence of seeds or embryos. The excised
seeds and/or embryos were cultivated in vitro on solid MS
and E20A medium with addition of biologically active
substances (2,4D, glycine, BAP, NAA). If the embryo
developed and the cell structures were formed their hybrid
character was evaluated using isozyme analysis (peroxidase,
acid phosphatase, esterase). The enormously high polyploidy
avoid using the DNA-flowcytometry.
In the I. cycle, 21 fruits were analyzed and 23.8% of them
contained seeds but no embryo was found. In the II. cycle,
205 fruits were analyzed, 10.7% contained seeds and 2.9%
embryos. In the III. cycle, 85 fruits were analyzed and
67.1% contained seeds and 37.6% contained embryos. In cycle
IV., 77 fruits were analyzed and 75.3% of them contained
seeds and 71.44 embryos.
The crossing ability is primarily influenced by genotype of
both partners. Best results were obtained with C.
sativus lines SM-6022, SM-6514 and SM-6026 and C.
melo genotypes MR-1 and PI 200819. The application of
biologically active substances on cucumber flowers during
pollination did not positively influence the formation of
embryos. The in vitro pre-cultivation of intact
(whole) extirpated seeds on solid MS or E20E medium with an
active substances followed by a cultivation of embryos
resulted in detection of developing embryos. In four cases,
the formation and differentiation of callus was observed.
The strong tendency to polyploidize was a reason of an
undifferentiated callus formation from embryos. The hybrid
character of two embryos was verified using isozyme
analysis. For the first time, the viable interspecific
hybrid embryos were produced and initiation of their
callogenesis and partly rhizogenesis or callogenesis was
observed. In cycle IV., two embryos developed into
flowering plants. They originated from the crossing between
cucumber breeding lines and C. melo MR-1. Their
morphological and physiological characteristics are under
Genes Affecting Stem and Fruit Color
Intensity of Straightneck Squash
Harry S. Paris
Agricultural Research Organization, Newe Ya'ar Research
Center, P.O. 1021 Ramat Yishay 30095, Israel
'Early Prolific Straightneck' is a straightneck-type squash
cultivar having dark stems and fruits which are light in color
when young but intensify during development. It was crossed with
'Vegetable Spaghetti' and with other stocks of known genotype in
order to identify the genes responsible for its dark stems and
developmentally intense coloration. The results indicated that a
weaker allele of gene D, named Ds, is
responsible for the dark stems, but that this allele has no
effect on fruit coloration. Gene L-2 was found to be
responsible for the intensification of fruit color during
Evaluation of a Melon Collection for Diseases Resistances
M. Pitrat1, G. Risser1, F. Bertrand2, D. Blancard2, H. Lecoq2
INRA, Station dAmélioration des Plantes Maraîchères (1) and Station de Pathologie Végétale (2), BP 94, F-84143 Montfavet cedex (France)
The Cucumis melo collection maintained at INRA in Avignon
(France) is not representative for the complete diversity of
melon; for instance accessions from Africa and central and south
America are under-represented. A part (635 accessions) of this
collection has been evaluated with at least one of the following
Fusarium wilt has been tested in artificial inoculation with
races 1, 2 and 1-2. Resistance to race 1 (400 accessions tested)
was found mainly in accessions from Eastern and Central Asia
(resp. 56 % and 30 %). Resistance to race 2 (353 acc. tested) was
observed mainly in accessions from Central Asia, Russia and
France (resp. 46 %, 31% and 30%). Resistance to race 1-2 (271
acc. tested) was observed only in accessions from Eastern Asia.
A few accessions (58) have been tested with Pyrenochaeta
lycopersici. Most of them were moderately susceptible or
resistance except accessions from Central Asia which were highly
No high level of resistance to scab (Cladosporium
cucumerinum) has been found among 261 accessions tested.
Moderate level of resistance were found in accessions from North
America, Spain and Eastern Asia.
About 400 accessions were tested with different strains of
powdery mildew. Almost all were resistant to races 0 of
Sphaerotheca fuliginea and Erysiphe cichoracearum.
Only a few genotypes from Central Asia were susceptible to races
0. Resistances to races 1 and 2 of S. fuliginea was observed
mainly in accessions from North America, Western Asia and India.
But resistance in american or Near East genotypes is the result
of breeding programs and the original sources of resistance were
indian genotypes. Resistance to race 1 of E. cichoracearum was
very frequent in accessions from Spain, North America or India
(resp. 90, 38 and 32 %). Here again resistance in american
genotypes is the result of breeding programs conducted for a long
Among 367 accessions tested for downy mildew (Pseudoperonospora
cubensis) only 3 accessions from India and one from Eastern Asia
were highly resistant.
The only source of resistance to Zucchini Yellow Mosaic Virus
(ZYMV) was from India. Necrotic reaction with F pathotype of ZYMV
has been observed on 36 % of 531 accessions, mainly from Central
Asia and Spain (76 % and 71 % resp.). The lowest frequency was
observed in genotypes from Eastern Asia (10 %).
Resistance to Melon Necrotic Spot Virus (MNSV) has been found in
7 % of 532 tested accessions mainly from North America (29 %).
Watermelon Mosaic Virus type Morocco (WMV-M) induces on some
genotypes a necrotic reaction. This reaction was frequently
observed in accessions from Eastern Asia and France (77 and 56 %
resp). Among 341 tested accessions, resistance to this virus was
found in accessions from India and North America (19 and 17 %
In conclusion, India and Eastern Asia are very important sources
of disease resistance. Some particular accessions are highly
interesting because they are multi-resistant (for instance PI
161375, MR-1, PI 124112, PI 414723). Conversely no unique
resistance was observed in accessions from Central Asia. Only 4
out of 138 accessions tested with 7 different pathogens were
susceptible to all of them.
Performance of Tropical Pumpkin Inbreds and Hybrids
D. N. Maynard
University of Florida, Bradenton FL USA
Cucurbita moschata (Duchesne) Poir. is a pumpkin-like fruit that
is grown throughout the tropics and subtropics. This species is
also known as calabaza in Puerto Rico, auyama in the Dominican
Republic, calabash or pumpkin in the English-speaking islands,
ayote in Central America, and zapallo in South America. Plants
are monoecious, and insects, primarily honeybees and bumblebees,
are required for transfer of pollen from staminate to pistillate
flowers. Fruits are produced along trailing vines that may
spread up to 15 m from the base or crown of the plant. Each
plant commonly produces two to five fruits; however, some
selections may produce as many as nine fruits per plant. Fruit
weight ranges from 2 to 20 kg. Fruit shape varies in unimproved
types from globe, round, oval, obovate, pear, oblate and gourd,
to elliptic. Likewise, there is much variation in rind color
from green immature fruit to light-orange mature fruit and in
rind pattern from piebald (pinta) to mottled. The rind may be
smooth or warted. The fruit wall varies in color through several
shades of yellow to orange and is from 2 to 8 cm thick.
Bush/short-vine and intermediate-vine length tropical pumpkin
inbreds and hybrids have been developed and evaluated. Several
of the short-vine hybrids produce yields that are equivalent or
superior to those of the traditional long-vined inbreds. The
short-vine hybrid plants generally produce fruit which is smaller
and has thinner flesh than the long-vined inbreds so they may not
be suitable where market requirements dictate large fruit.
Soluble solids concentrations in fruit from the short-vined
hybrids is equal or superior to that in fruit from traditional
Inheritance of Peduncle Size in the Cucumber and Its Linkage
Relationships with Other Characters
N. Fanourakis1, N. Golfinopoulou1, A.
Stavrianou1, and E. Tzifaki2
1Technological Educational Institute, Heraklion
Crate. 71500 Greece; 2Institute of Viticulture,
Vegetable Crops and Floriculture, Heraklion Crete, 71110
Abstract. The fruit of cucumber is joined to the main
stem by the peduncle which, in most varieties, is extended from
one to several centimeters. Most European slicer varieties have
a long peduncle which at harvest is cut either close to the
plant, so that it accompanies the fruit to the market, or close
to the fruit so it remains on the plant. Its presence is usually
undesirable because it becomes wilted if remains on the fruit, or
it is a point of infection by some diseases through the wound if
it remains on the plant.
The way of peduncle size and its genetic relationships with some
qualitative characteristics of cucumber were investigated. Line
786 which was found to have the longest peduncle was crossed with
a local population which lacks peduncle. F1 plants
were selfed and also backcrossed to either parent so that
F2 and BC populations were generated. Parents,
F1, F2, BCP1 and BCP2
generations were evaluated for peduncle size. Plants were also
classified for sex expression, spine color and mature fruit color
for possible linkage association with the peduncle size.
Arrangement of plants in discrete classes for peduncle size in
the segregating generations was attempted to test the segregating
ratios by x2 analysis. However the resulting
phenotypic classes did not fit to known ratios of the Mendelian
inheritance. A quantitative approach could probably explain
better the inheritance of this characteristic. The observed
ratios for the characteristics of sex expression, spine color,
and mature fruit color within each class of peduncle size
generally did not indicate significant deviations from the
observed total ratio of each characteristic. Thus independent
inheritance is suggested for the peduncle size and the
characteristics of sex expression, spine color, and mature fruit
Two Independent Loci for White and White-Yellow Corolla in
Cucurbita maxima Duch.
Department of Plant Genetics, Breeding and Biotechnology,
Warsaw Agricultural University, Warsaw, Poland
Abstract. In the genus Cucurbita petals
lighter than the typical yellow-orange or orange have been
described twice. The character named light yellow corolla
was described by Scarchuk in 1974 in Cucurbita pepo
var. ovifera Alef. as a recessive trait (ly).
Cream corolla was described for the second time by Roe and
Bemis in 1977 in Cucurbita moshata cv. 'Butternut'.
Colour was introduced from C. okeechobeensis Bailey.
A two-loci hypothesis was accepted by the CGC Gene List
Committee (Hutton and Robinson, 1992). Gene cr -
cream corolla in homozygous stage cr/cr gives
cream to nearly white petals, cr/+ yellow ones and
+/+ orange. Gene i has been described as intensifier
of cr gene for cream flowers.
In this paper the occurrence of the white and white-yellow
corolla in the third species C. maxima is analysed.
The white corolla form was separated in the F5
from cross 'Ispanskaya x Emerald Squash'. The colour of the
petals according to Ostwald tables (Ostwald Ed. A. Muster
Schmidt Berlin S.W. 68) was defined as 1/VI/1ea/1. The
margins of the petals of this form were less dentate and had
tendency to curl in the upper part of the corolla.
The form white-yellow corolla was isolated in the
S3 generation from the cv. 'Rieesen-Melonen'.
The petals had a slightly different shade (according to the
Ostwald 1/VI/ga/2). In contrast to white corolla the petals
were strongly dentate.
In order to explain the mode of inheritance of the white and
white-yellow corolla traits classical genetic analysis was
performed. Each of the forms was crossed with an inbred
line (138) characterised by intensely orange petals
(according to Ostwald tables 1/XII/na/4). White and white-
yellow corolla lines were crossed to analyse independent
inheritance of both characters. These two lines were
subsequently crossed with the yellow-green leaves line
described earlier by Korzeniewska (1992). Hypothetical
segregation ratios were checked by the chi square test.
For the first time the inheritance of the characters white
corolla (wc) and white-yellow corolla (wyc) in
Cucurbita maxima Duch. was described. Both
characters are recessive. The genes which cause them occur
in distant loci. Dominant alleles of these genes complement
with each other giving orange colour. The character white
corolla and white-yellow corolla were not linked with the
character yellow-green leaves. For a better evaluation of
the character carotenoids in the petals should be analysed.
Hutton, M.G. and R.W. Robinson. 1992. Gene list for
Cucurbita spp. Cucurbit Genet. Coop. 15:102-108.
Korzeniewska, A. 1992. New genes in Cucurbita
maxima Duch. Fifth Eucarpia Cucurbitaceae Symposium,
July 27-31, 1992, Skierniewice-Warsaw, Poland, 75-78.
Roe, N.E. and W.P. Bemis. 1977. Corolla colour in
Cucurbita. J. Heredity 68:193-194.
Scarchuk, J. 1974. Inheritance of light yellow corolla and
leafy tendrils in gourd (Cucurbita pepo var.
ovifera Alef). HortScience 9:464.
Leaf Yield Components and Nutritional Quality of Zambian Pumpkin
(Cucurbita spp.: Cucurbitaceae) Landraces
C. Gwanama1 and K. Nichterlein2
1Department of Crop Science, University of Zambia,
P.O. Box 32379, Lusaka, Zambia, and 2Plant Breeding
and Genetics Section, International Atomic Energy Agency, P.O.
Box 100, A-1400, Vienna, Austria
Abstract. Cucurbita species are extensively used
for leaf consumption in Zambia. The current study had the
objective of evaluating leaf yield potential and nutritional
quality of 36 pumpkin landraces collected from the major
agroecological zones of Zambia and to establish the leading
selectable traits contributing to leaf yield. Two trials
conducted at farms near Lusaka in 1994/5 revealed significant
differences among the genotype means at p=0.05 for number of node
with first female flower, length of internode with first female
flower, length of primary vine, number of primary branches per
main vine and number of leaves per plant. Significant
correlations were obtained among leaf yield and its components,
especially length of main vine (r=0.848**) and number of primary
branches per main vine (r=0.905**). Number of primary branches
per main vine had the highest direct effect on yield (0.6883)
although length of main vine had a big contribution to yield via
number of primary branches (0.6188). In general Cucurbita
moschata landraces were more branching and leafy than C.
maxima varieties. Additionally leaf crude protein analyses
showed significant differences among genotype means. It is
concluded that genetic variation exists in the germplasm
collection and that number of primary branches per main vine is
the most important yield component. Variation also exists in
nutritional quality although commercialized cultivars are not
superior to the rest.
29-D, A Melon Inbred with Multiple Diseases Resistances
Department of LIfe Sciences, Bar-Ilan University, Ramat-Gan,
Cucumis melo PI 124111F was stabilized for resistance to
downy mildew, powder mildew race 1 and 2 and Fusarium wilt
races 0, 1, and 2. This line was crossed to a susceptible Ha'ogen
type and then backcrossed to a susceptible orange-flesh cantaloupe.
20-D was selected after 10 generations of selections and selfing.
29-D is resistant to downy mildew caused by Pseudoperonospora
cubensis, powdery mildew caused by races 1 and 2 of
Sphaerotheca fuliginea and races 0, 1, and 2 of Fusarium
oxysporum f. sp. melonis. This inbred line produces a
vigorous vine with globular, netted, sutured fruits. The fruit has
a small cavity and mild orange flesh. TSS is ca. 12%. 29-D
combines beautifully with various partners such as Ananas types,
cantaloupes and charantias. F1 hybrid plants are
resistance, under field conditions, to downy mildew, powder mildew
race 1, and Fusarium wilt. Resistance to race 2 of powdery
mildew is incomplete. F1 fruit type was strongly
affected by the partner used for crossing.