2. CUCURBITACEAE
• 117 genera and 825 species
• 30 species of nine genera are used as cultivated
plants
• Most of the cucurbits are monoecious & annual
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13. Origin
• This genus comprises of about 30 species
distributed over two distinct geographic areas
i. South East Himalayas – Asiatic group
• The important in this group is cucumber with basic
chromosome no. x = 7.
ii. African group – Africa, middle East & Central
Asia
• Musk melon is one of the important members of
this group. The basic chromosome no. x = 12.
Few tetraploids and hexaploids are also found in
this group.
17. Cucurbits
• Cucurbits form an important and a big group of
vegetable crops cultivated extensively in the sub-
tropical and tropical countries.
• Cucurbits have been used in many traditional
medicines of India different parts of the plant are
used to relieve diabetes, hypertension, as a
stomachic, laxative, antibilious, emetic, antihelmintic
agent, for the treatment of cough, respiratory
diseases, skin diseases, wounds, ulcer, gout and
rheumatism.
18. Characteristic features of cucurbits
• Long tap root system- 175-180 cm
• Viny growth habit (except summer squash)
• Annuals (except pointed gourd, ivy gourd, kakrol and
chayote)
• Frost-sensitive
• Monoecious (except pointed gourd, ivy gourd and kakrol)
• Cross pollinated- honey bees and bumble bees
• Propagated by seed (except pointed gourd, ivy gourd and
kakrol)
19. • Multi seeded fruit (except chayote- viviparous :
single seed /fruit & the seed germinates inside
the fruit)
• Mainly fruit i.e, ‘pepo’ is the edible part
(exceptions: chayote all plant parts edible,
pumpkin besides immature and mature fruit,
flower is also edible)
• Cucurbitacins- bitter principle
• The bitter flavour of bitter gourd is due to the
alkaloid momorcidine produced in fruits and
leaves
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22. Flowering:
• Majority of cucurbits start flowering 30-45 days after
sowing and follows a definite sequence
• An alternated sequence of male and female flowers
follows upto fruit set
• First 4-6 flowering nodes bear male flowers and later
female flowers
• Developing fruits in a vine determine production of
further female flowers further down in the vine
• In crops where immature fruits are harvested at tender
stage, this kind of inhibiting mechanism will not be
perceptible.
23. • But in melon, pumpkin,
ash gourd etc. even if
perfect or female
flowers are produced
in the vine, fruits may
not set or develop fully
or shed in immature
condition.
• That is why no. of
fruits / vine in a seed
crop will be less (4-5)
than in a vegetable
crop (12-15) in bottle
gourd, ash gourd and
cucumber
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25. Metaxenia
• Cucurbitacins – high in fruits, roots and less in leaves.
• Pollen grain also carries fairly good amount of bitter principles
• Common in cucumber, bottle gourd and rarely noticed in ridge
gourd and snake gourd
• When a non bitter ovule is fertilized with a bitter pollen grain,
resultant fruit is bitter and the phenomenon is known as
metaxenia
• Wild plants within a species play a major role in the transfer of
bitterness to cultivated varieties
• Adverse factors, particularly stress conditions also induce
bitterness even in a non bitter variety
Xenia is the effect of genes from the male parent on the
development of fruit or seeds.
Metaxenia is the effect of pollen on fruit shape and other fruit
characteristics.
26. Sex forms in cucurbits
1. Hermaphrodite: ‘Satputia’ cultivar of ridge gourd, cucumber
and muskmelon.
2. Monoecious: cucumber, bottle gourd, bitter gourd,
watermelon, pumpkin, squash, ash gourd, ridge gourd,
sponge gourd, snake gourd etc.
3. Andromonoecious: watermelon (in some cultivars),
muskmelon (dessert type).
4. Gynomonoecious: cucumber.
5. Gynoecious: cucumber
6. Trimonoecious or gynoandromonoecious: genetic stock of
bitter gourd
7. Androecious: pointed gourd.
8. Dioecious: pointed gourd, ivy gourd and kakrol (Momordica
dioica) among cultivated cucurbits.
27. Sex modification
• Majority of cucurbits are monoecious and sex ratio (male:
female) ranges from 25-30:1 to 15: 1
• Sex ration is influenced by environmental factors
• High N content in the soil, long days and high temp. favour
maleness
• Besides environmental factors, endogenous levels of auxins,
gibberelins, ethylene and abscisic acid also determine sex
ration and sequence of flowering.
• A primordium can form either a female or a male flower and
it can be manipulated by addition or deletion of auxins.
• Endogenoues application of plant growth regulators can
alter sex form, if applied at 2-4 leaf stage.
28. • High ethylene level induces female sex and is
suggested to increase female flowers in cucumber,
musk melon, summer squash and pumpkin.
• In cucumber, maleic hydrazide (50-100 ppm), GA3 (5-
10 ppm), ethrel (150-200 ppm), TIBA (25-50 ppm),
boron ( 3 ppm) also induce flowers
• Gibberelins promotes maleness and is antagonistic to
the action of ethylene and ABA.
• In fact gynoecious line of cucumber is maintained by
inducing male flowers through spray of GA3 (1500-
2000 ppm)
• Silver nitrate (300-400 ppm) also induces maleness
29. Snake gourd – Trichosanthes cucumerina – 2n = 24
• Habit - Trailing or climbing annual herb
tendrils.
• Root - Tap root system
• Stem - Angular, succulent herbaceous
pubescent prostrate.
• Leaf - Simple alternate large serrated margin
reticulate venation, very minute hairs are present on
lower surface 5-7 lobed.
30. • Inflorescence – Raceme
• Flower - Pedicellate – solitary
arising from the axil of leaf white
regular
• Calyx – Sepals 5, gamosepalous
imbricate aestivation
• Corolla - Petals 5, gamopetalous,
margin of each petal ends in hair
like structure special out growth are
found on the petal called papilla
• Androecium – 3 stamens united
filaments free.
• Gynoecium – Inferior ovary, parietal
placentation fruit long more than 20-
30 cm pepo tapering with white and
green patulous.
31. Bitter gourd – Momordica charantia – 2n = 22
• Habit - Climate climbs by tendrils
• Stem – herbaceous, delicate hair an present
• Leaf – Ex stipulate, pubescent upper surface is
dark green low surface is light green.
• Inflorescence – Raceme male flower arise
singly or in shorter female flower an solitary.
• Flower – Axillary epigynous, pedicellate
32. • Calyx – Green, imbricate aestivation
• Corolla – yellow imbricate aestivation inserted in
calyx tube.
• Androecium – Stamens and filament are free
• Gynoecium – Tricarpellary, separated by false septa
inferior ovary seed arrange in parietal placentation
• Fruit – Pepo pendulous
• Seeds – Numerous, seeds brown or black.
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37. Ribbed gourd – Luffa acutangula – 2n = 26
• Habit - Annual herb climber, with branched
tendril
• Root – Tap root system
• Stem – Herbaceous furrowed / angled,
pubescent, prostrate.
• Leaf – Alternate, ex stipulate, 5-7 lobed,
simple, palamately veined.
38. • Inflorescence – raceme with only male flowers
• Flower – 5 petals and 5 sepals imbricate aestivation
• Androecium – 3 stamens
• Gynoecium – Inferior ovary, female flowers are
solitary style short trifid stigma.
• Fruit – Pepo with ridges on its surface may seeded
in parietal placentation
• Seed – Numerous black in colour.
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41. Cucumber – Cucumis sativus – 2n=24
• Habit – Trailing or climbing habit, annual herb
monoecious
• Root – Extensively and largely superficial
• Stem – Poor angled, tendril unbranched
• Leaf – long petiole triangular ovate, rough 3-5 angled
or shallowly lobed with acute sinuses base cordate.
• Flower – male predominant, borne in axillary clusters
on slender pedicels, female solitary, axillary with
stout peduncle.
42. • Calyx – 5 narrow lobes, long
• Corolla long bell shaped, yellow deeply 5 partite
hairy wrinkled.
• Androecium – Stamen 3, filaments free
• Gynoecium – 3 united inferior carples simple style 3
stigma.
• Fruit – pendulous variable in shape and size merely
globular to oblong elongated flesh pale green
characteristic cucumber odour may seeded except in
parthenocarpic cultivars.
• Seed – flat white
