This document discusses hybrid seed production techniques in cucurbits such as cucumber. It notes that most cucurbits are monoecious with male and female flowers on the same plant. For hybrid seed production, male and female plants must be isolated and hand-pollinated. The female flowers are bagged before opening and rubbed with pollen from the male variety. After pollination, the bags are replaced to prevent cross-pollination. Seeds are later harvested from mature fruits. Key production steps include isolation, rouging, harvesting at maturity, and seed extraction methods like fermentation.

1. HYBRID SEED PRODUCTION
TECHNIQUES IN CUCURBITS
INCLUDING CUCUMBER
- Hridya V Rejeendran
- Ph. D Scholar
Tamil Nadu Agricultural University
Department of Seed Science & Technology
SST 801 HYBRID SEED PRODUCTION

2.  Most of the cucurbits are monoecious in character and a few are
dioecious.
 Male & female flowers borne separately in the same plant.
 Female flowers have a knob like structure below the flower.
 Flowers open early in the morning except bottle gourd and ridge
gourd wherein it opens in the evening.
 Most of the cucurbits are cross pollinated crops. Pollination is
largely done by insects (Jarnail et al., 1972).
Floral biologyFloral biology

3. Male and female should be bagged
with butter paper or polythene bags
(15x10 cm) one day before the
opening of the flower.
At the time of flower opening the
bags are removed & the pollen from
the parent are rubbed over the stigma
of the female flowers of the same
variety.
Female flowers are again bagged to
avoid contamination.
Bags should be removed one week
after pollination. Fruits are removed
when they are fully matured.
In bottle gourd, ridge gourd &
sponge gourds dried fruits are kept
for storage & the seeds are extracted
from them at the time of planting.

4.  Seeds of cucurbits are highly sensitive to soil moisture.
 Seeds can be pre – germinated before actual field sowing
by water soaking for 4hr.
 Germinated seeds can be separated daily till 6 days.
 The seed germinating after 6 days are of poor vigour.
 Germinated seeds can be sown in the pits by making
small holes and dropping the seeds in the holes.

5. Land should be free of volunteer plants. Generally the soil
should be well drained and aerated.
Land should be free of volunteer plants. Generally the soil
should be well drained and aerated.
Land Requirements
Isolation
Foundation – 1000 m Certified – 500 m
Pollination is largely done by insects. Isolation distance all around
seed field is necessary to separate the crop from field of other
varieties, fields of the same variety not conforming to varietal purity
and from wild cucurbit species.

6. Season
• June – July & February-March
Seed rate
• 2.5 kg / ha
Spacing
• Sow the seeds in the pit size of 45 x 45 x 45 cm at 2.5 x 2.0
m spacing
Female flower increase
• Spraying of ethrel 200-250 ppm at two leaf stage and after a
week of 1st spray.

7. HYBRIDS DURATION
YIELD/
ha
SALIENT FEATURES AREA
TNAU Ash
gourd
Hybrid CO 1
120-130 D 90 t/ha.
Fruits are oblong and
medium in size.
Tamil Nadu
BITTER GOURD IARI
Pusa Hybrid-1
55-60days.
first picking
200 q/ha.
Fruits are medium long,
medium thick, glossy-
green, suitable for
pickling and
dehydration.
Pusa Hybrid-2
55-60days.
first picking
190-200
q/ha.
Fruits are spindle
shaped, glossy green
skin colour without
tubercles
Karnataka,
Tamil Nadu
and Kerala

8. BOTTLE GOURD
Pusa Hybrid 3
IARI
- 425 q/ha
Fruits are green, slightly club
shaped without neck, suitable
for easy packing and long
distance transportation,
All over India
TNAU Bottle
gourd Hybrid
CO 1
- 80 t/ha.
Fruits are cylindrical, without
crook neck, medium sized
Tamil Nadu
Hybrid -Kashi
Bahar
IIVR
-
500-550
q/ha.
This is a long fruited hybrid
with green vine and vigorous
growth, fruit straight, light
green,
U.P., Punjab,
Bihar and
Jharkhand

9.  Family – Cucurbitaceae
 Origin – South Asia (India)
 Chromosome no. 2n =24
Introduction
 Summer vegetable crops
 Bitter taste of the fruit – due to tetracyclic
terpenes in seeds .
 Oil from its seed is good for the brain.
 Family – Cucurbitaceae
 Origin – South Asia (India)
 Chromosome no. 2n =24
Introduction
 Summer vegetable crops
 Bitter taste of the fruit – due to tetracyclic
terpenes in seeds .
 Oil from its seed is good for the brain.

10. Climate
 Warm season crop, it does not withstand even light frost.
 Seed does not germinate – below 11°C
 Grows best at temperatures between – 18 to 24°C.
 Female flowers are produced during the short days with cool
temperatures and low light.
Soil
 Sandy to heavy clay is the best suited.
 pH – 5.5 and 6.7.
 The soil should be well drained.
Climate
 Warm season crop, it does not withstand even light frost.
 Seed does not germinate – below 11°C
 Grows best at temperatures between – 18 to 24°C.
 Female flowers are produced during the short days with cool
temperatures and low light.
Soil
 Sandy to heavy clay is the best suited.
 pH – 5.5 and 6.7.
 The soil should be well drained.

11. The dehiscence occurs when temperature ranges from 20.5 to
21.50
c between 2.30 to 3.45 A. M. and it completes before 5
A.M.
The stigma becomes receptive 12 hours before and remains
so 24 hours after opening of flowers at moderate
temperature.

12.  Hills are prepared at proper spacing by adding well-
rotten organic manure.
 North India - kharif - June to July; summer - January
to Feb.
 South India - October to November.
 Seed rate - 1.5kg for male parent and 3.5kg for female
parent for a hectare.
 Hills are prepared at proper spacing by adding well-
rotten organic manure.
 North India - kharif - June to July; summer - January
to Feb.
 South India - October to November.
 Seed rate - 1.5kg for male parent and 3.5kg for female
parent for a hectare.

13. • Inflorescence – Cymose.
• Monoecious.
• Flowers are unisexual and actinomorphic.
• Stigma receptivity – maximum 2 hrs.
• Fruit – Pepo.
• Exalbuminous.
• Male flowers have 3 stamens with free filaments
and anthers.
• Female flowers have 3 united inferior carpels,
with a style and 3 thick stigmas.
• Inflorescence – Cymose.
• Monoecious.
• Flowers are unisexual and actinomorphic.
• Stigma receptivity – maximum 2 hrs.
• Fruit – Pepo.
• Exalbuminous.
• Male flowers have 3 stamens with free filaments
and anthers.
• Female flowers have 3 united inferior carpels,
with a style and 3 thick stigmas.

14.  Female flower :
• Produced during the short days with cool temperatures and
low light
• Usually solitary.
• The corolla is yellow, about an inch long, bell shaped, 5 petals,
wrinkly and hairy
• It is having 3 united inferior carpals, with a style and 3 thick
stigmas
 Male flower :
• These are produced in the axil of the leaf
• These are having 3 stamens with free filaments and anthers
 Female flower :
• Produced during the short days with cool temperatures and
low light
• Usually solitary.
• The corolla is yellow, about an inch long, bell shaped, 5 petals,
wrinkly and hairy
• It is having 3 united inferior carpals, with a style and 3 thick
stigmas
 Male flower :
• These are produced in the axil of the leaf
• These are having 3 stamens with free filaments and anthers

15. Hybrids Yield
Swarna sheetal 20-30 t/ha
Pusa sanyog 15 t / ha
NS 45 200 g weight.
NS 46 150 g weight

16.  Lack of standardized techniques for commercial seed
production of hybrids is one of the major reasons that restrict
the popularization of hybrid seeds.
 Production of hybrid seed of cucurbits needs some special
considerations.
 Depending on the floral biology, one of the following methods
can be followed for large scale hybrid seed production.
a. Picking of male flowers & artificial pollination
b. Picking of male flowers & insect pollination
c. Use of gynomonoecious lines (cucumber)
d. Use of male sterile lines (muskmelon, squash, pumpkin)

17. 1. Picking of male flowers and artificial pollination
In monoecious plants, emasculation is not required. Female
and pollen parent lines are planted alternately in an isolated
field.
Male flowers from the female parent are pinched before they
open. Pistillate flowers of the female parent are artificially
pollinated with the pollen of the male parent using cotton
puffs by manual labour.
2. Picking of male flowers and insect pollination
Female and pollen parent lines are planted alternatively in
an isolated field.
Male flowers from the female parent are pinched before they
open. Female flowers are left on the seed parent and
allowed to be pollinated by insects from the pollen parent.

18. 3. Use of gynoecious lines (Cucumber)

19.  The gynoecious sex form have been commercially exploited in
hybrid seed production of cucumber (Pusa Sanyog) at IARI R.S.
Katrain.
 Performance is unstable under high temperature and longer photo
period. It is not suitable for tropical regions.
 In IARI, tropical suited gynoecious lines are developed.

20. Maintenance of gynoecious lines
 In gynoecious lines, only pistillate flowers are produced and so
it requires staminate flowers for self pollination.
 For production of staminate flowers, GA3 100 ppm is sprayed
thrice at 15 days interval from 2nd
leaf stage or single foliar spray
of silver nitrate 600 ppm is done before 1st
flower open.
 It induces staminate flowers for fertilization of pistillate
flowers.
 At physiological maturity / ripening, fruits are harvested and
seeds are extracted. Such seed when sown in next generation
will produce only pistillate flower.

21.  The hybrid seed can also be produce in cucurbits by the
application of chemicals for attaining the sex of cucurbits.
 Specific chemicals are known to induce femaleness and maleness
as desired.
 The spraying of ethrel (2-choloro-ethyl-phosphonic acid) 200-300
ppm at two and four true leaf stage and another at flowering is
useful for inducing the pistilate flower successively in first few
nodes on the female in bottlegourd, pumpkin and squash for F1
seed production, Verma et al., 1985.

22. Field inspection and rouging
 Minimum of 3 field inspections
- before flowering
- during flowering and at immature fruit stage
- during mature fruit stage
 In case of hybrids, at least 4 field inspections are necessary
 Isolation, planting ratio, off-types, nicking of male buds in
the seed parent block, ascertaining accuracy in
emasculation or to check pollen shedding cymes in male
sterile lines and to verify true fruit characteristics.
 Maximum percentage of off types permitted
 foundation seed - 0.10%
 certified seeds - 0.20%

23. HARVESTINGHARVESTING
 Harvesting of the fruits at appropriate maturity stage should be
done.
 In some cases one picking for consumption/commercial as fresh
vegetable does not affect the ultimate seed yield but adds to the
farmers income.
 Fruits of bottle gourd are ready for seed beyond the edible fruit
maturity.
 Skin of bottle gourd becomes hard and colour changes to light
brown or yellow at seed maturity.
 Colour of bitter gourd and snake gourd changes yellow /
orange / red from green at maturity.
 In ash gourd white colour ashy coating and metallic sound
indicates the maturity.
 In ribbed gourd, complete drying of fruits and turning of colour
from green to brown.

24. Seed extraction
Seed separated from the pulp by
•Fermentation and repeated washings OR
•Mechanical OR
•Chemical methods OR
•Dry extraction method

25. Fermentation method
 Pulp is allowed to ferment in wooden or non-metallic barrels
for about 30 hrs with occasional stirring to prevent growth of
moulds of the seed surface.
 Separated clean seeds sink to the bottom and can be collected,
washed and dried.
 Then the seeds are separated by rubbing with hands with
excess quantity of water.

26. Mechanical method
 In the mechanical method, fruits are cut and macerated mechanically
and the pulp is squeezed forcibly for separating the seed.
Chemical method
 In the chemical method, seed is extracted with the use of an acid or
alkali.
 Eg. In ash gourd the fruits are cut into 4 pieces and the central
portion is scooped out. Then the seeds are extracted using HCL.
 1N Hydrochloric acid (50-60 ml) is thoroughly mixed with 10kg
pulp and allowed to stand for about 30 min.
 Seed is then washed thoroughly to remove the residues of acid /
alkali and dried to safe MC.

27. Dry Extraction
• Dry extraction processes are usually adopted for ribbed gourd &
bottle gourd
– In ribbed gourd the dried pods are cut opened at the distal end
and seeds are collected and cleaned
– In bottle gourd the fruits are cut opened at the proximal end and
seeds are collected
• Seed is scooped out of the fruit and sun dried. The clean seed is
then removed by rubbing over a sieve and winnowing or blowing to
separate the inert matter.
• Seeds may be washed once, if necessary and then re-dried to safe
seed MC.
• In this method machines, like Axial Flow Vegetable Seed Extractor

28. Seed recovery
Bitter gourd - 30%
Snakegourd - 15-16%
Ribbed gourd - 13-14%
Ash gourd - 1.0-1.3%
Drying
 Drying is done to reduce the MC in the seed to safe limit because
SMC affects the germination and storability.
Grading or size separation
 Various equipments such as air-screen cleaners, gravity and indented
cylinder separators, etc. are available in the market which can be
taken up as per the requirements.
 Farmer can use even hand sieves for taking up the enterprise on a very
small scale.
 Mostly 16/64” round perforated sieves are used for grading

29. Crops Seed yield (kg/ha) Test Weight (g)
1000 seedOpen pollinated Hybrid
Ash gourd 250-400 200-350 70
Bottle gourd 300-500 240-500 150
Bitter gourd 100-300 80-240 60
Ridge gourd 300-400 240-320 90
Sponge gourd 300-400 240-320 90
Muskmelon 200-300 240-320 25
Watermelon 250-400 160-240 70
Round melon 300-400 175-320 80
Long melon 200-300 240-320 30
Cucumber 300-400 160-240 23
Pumpkin 300-400 240-320 170
Summer squash 300-400 240-300 150
Winter squash 300-400 250-300 125
Snake gourd 300-400 250-300 150