INTRODUCTION
Tuberose
(Polianthes tuberosa L.) is one of the most important
tropical ornamental bulbous flowering plants cultivated for production of long lasting flower spikes. It
is popularly known as Rajanigandha or Nishigandha. It belongs to the family Amaryllidaceae and is
native of Mexico. Tuberose
is an important commercial cut as
well as loose flower crop due to pleasant
fragrance, longer vase-life of spikes,
higher returns and wide adaptability to
varied climate and soil. They are
valued much by the aesthetic world for
their beauty and fragrance. The
flowers are attractive
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| Field view of Tuberose |
and
elegant in appearance with sweet fragrance.
It has long been cherished for
the aromatic oils extracted from its
fragrant white flowers. Tuberose blooms
throughout the year and its clustered
spikes are rich in fragrance; florets
are star shaped, waxy and loosely
arranged on spike that can reach
up to 30 to 45 cm in length.The flower is very popular for its strong fragrance and its
essential oil is important
component of highgrade perfumes.
‘Single’ varieties are more
fragrant than ‘Double’ type and contain
0.08 to 0.14 percent concrete which
is used in high grade perfumes (Singh
and Uma, 1995). There is high demand
for tuberose concrete and absolute
in international markets which
fetch a very good price. Flowers
of the Single type (single row
of perianth) are commonly used for
extraction of essential oil, loose flowers,
making garland etc., while that
of Double varieties (more than two
rows of perianth) are used as cut flowers,
garden display and interior decoration.
Fragrance of flowers is very
sweet, floral and honey-like and can
help give emotional strength. It is
known to improve an individual’s capacity
for emotional depth and can stimulate
the right side of the brain and
bring serenity to the mind and heart.
The flower spike of tuberose remains
fresh for long time and finds a
distinct place in the flower markets. Due
to its immense export potential, cultivation
of tuberose is gaining momentum
day by day in our country.
Soil
Tuberose can be grown
on wide variety of soils
ranging from light, sandy loam to a clay
loam. It can also be successfully
grown as a commercial crop even
in those soils which are
affected by salinity and alkalinity
conditions if better agronomical practices
are adopted. The soil should be at
least 45 cm deep, well drained,
friable, rich in organic matter
and nutrients with plenty of moisture
in it. Tuberose should be grown
in well drained place. Crop is
sensitive to water stagnation and it
cannot tolerate water logging even
for a short period. So it is very essential
to ensure proper drainage or
else planting should be done on bund.
Fertile, loamy and sandy soils
having a pH in the
range of 6.5 to 7.5 with good
aeration and drainage are
ideal for tuberose cultivation. A place
protected from strong winds is preferable.
Cultivars
Single flower type (Rajat Rekha, Shringar,Prajwal, Mexican, Calcuttia
and local types)
Double flower type
(Swarna Rekha,Suvasini, Vaibhav, Arka Nirantara, Mexican,Calcuttia
and local).
Selection of site
Tuberose is a
sun-loving plant. For attaining good
vegetative growth and maximum yield of
flowers, a site should be chosen,
where the plants will get plenty of
sun throughout their growing period. The
soil should have sufficient moisture
holding capacity. A place protected
from strong wind, hot and cold waves is
preferable, so that there is no
damage of flower stalk. In shady
situation, the plants grow
tall and lanky and the flowering is
adversely affected. They are highly susceptible
to water stagnation and poor
drainage conditions and hence require
well drained and aerated soil.
Field or land Preparation
The land should be
ploughed deep to a good tilth, 2-3
times , to a depth of 30
- 45 cm. The first ploughing should be
done in January. The field is left exposed
to sun for at least 15 days
that destroys the
weeds and insectpests. The
second ploughing can be done
about a month before planting. At
the time of the second ploughing, well
rotten farmyard manure at the rate
of 50 tonnes per hectare should be
incorporated into the soil. Then, the
soil is brought to a fine tilth by breaking
the clods and removing the weeds.
After field preparation, plots of convenient
sizes should be prepared with
irrigation channels, ridges and furrows
at the recommended spacing.
Propagation
Tuberoses are
propagated by bulbs, bulblets and seeds.
Multiplication by bulb-segments and
in vitro micro propagation from
scale stem-sections is also practiced.
Propagation by bulbs
Most common method
practiced for
the commercial multiplication of tuberoses
is through propagation by bulbs.
The bulbs remain dormant during
the winter months in places where
the temperature is low. The
dormancy of the bulbs can be successfully
broken by dipping thebulbs in 4% Thiourea solution for one hour if early planting is desired. Ethylene chlorohydrins can also be used for breaking the dormancy of bulbs. The bulbs are separated from the clumps by rubbing off the
loose scales
and the long roots should also be
removed. Selection of suitablebulbs is very important for successful cultivation. In general, spindle-shaped bulbs free
from diseases having
diameter between 1.5 and 3.0 cm
are suitable for planting. About 1.25
- 1.5 lakh bulbs (8 to 9 tons of bulbs)
are required for planting one hectare.
Propagation by bulb segments
Propagation through
mature bulbs is expensive,
therefore, multiplication of
growing stock can be done by division
of bulbs. Large sized bulbs having
2.1 cm or more diameter are suitable
for planting purpose. If the bulbs
are very large, they are cut into
2 to 3 vertical sections, each containing
a bud and part of the basal plate.
Each of these sections is treated
with copper fungicide
and planted vertically in a
rooting medium with its tip just showing
above the surface. A moderately warm
temperature should be maintained.
New bulblets along with roots
develop from the basal plate. At this
stage, bulblets are transferred to
the ground.
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| Tuberose bulbs in clumps |
SPACING:
A bulbs
are planted at an optimum spacing of 30 x 20 cm or 20 x 20 cm. About
40,000- 50,000 bulbs are required for one acre
planting of tuberose. ie) about 1,00,000 to 2, 00,000 bulbs are required for planting one hectare of land.
Depth of planting
The depth of planting
varies from 3.0 - 7.0 cm
depending upon the diameter of the bulb
and the soil type. It should be 2.5
times more than the diameter of bulbs.
While planting, the bulbs are planted at
the recommended plant-spacing, 4-6 cm
deep on the sides of the ridges.
Planting is deeper in sandy soil as
compared to clay soil. In
sandy loam soil planting of bulbs is
done at the depth of 6.0 cm. In general,
planting is done in such a way
that the growing portion of the bulb
is kept at the ground level.
Seed / bulb treatment
Dipping the bulbs in
4% solution of thiourea can break
the resting period. Pre-plant storage of
bulbs at 10°C for a period of 30
days will improve the plant growth,
increase spike and flower yield. Pre-planting
treatment of bulbs with GA3,
etherel or thiourea promotes early
appearance of flower spike and produces
longer spikes with maximum number
of florets. The bulbs are first thoroughly cleaned
and treated with Bavistin (0.2%)
for 30 minutes. Dipping the bulbs
for about 20-30 minutes in a solution
of Emisan (0.2%), Thiram (0.3%),
Captan (0.2%) or Benlate (0.2%)
is also recommended. Dry in
shade before planting or storing. Before
planting treat bulbs in systemic
fungicide and before storing in
contact fungicide.
Nutrient management
Tuberose responds
well to the application of
organic and inorganic manures.
Apart from FYM (20 tonnes/ha), a
fertilizer dose of 100 kg
N, 50 kg P2O5 and
70 kg K2O per hectare
is recommended for tuberose production.
For achieving increased essential
oil content in flowers and
for the maximum recovery of concrete,
a fertilizer dose of 80 kg N, 60
kg P2O5 and
40 kg K2O per hectare has been recommended. Of the full recommended dose of fertilizers,
half the N, the full dose
of P and K has to be applied at the
time of planting and the remaining half of
N is given as a top-dressing after 45
days of planting.
Micronutrients
Apart from N, P and
K, calcium, magnesium, sulphur,
iron, zinc, manganese, aluminium,
boron and copper have also been
found to influence the growth
and flowering in tuberoses. Foliar
spray of ZnSO4 0.5%
+ FeSO4 0.2% + Boric acid 0.1% improves growth and flowering.
Use of Growth
regulators
Foliar application of
GA3 at
50 to 100 ppm thrice at 40,
55 and 60 days after planting is
found to be beneficial. The
application of CCC at 5000 ppm and
GA3 at
1000 ppm induces early
flowering, increased
flower stalk production and
improves the quality of flowers.
Water and Irrigation
Management
It is very essential
to irrigate before planting to provide
optimum moisture for sprouting and
further irrigation should be avoided
until the bulbs are sprouted.
Subsequent irrigation to
the crop is given, depending upon the
prevailing weather conditions.In the summer months, irrigation is recommended twice a week and during winter at 10 days
interval.
Intercultural
Operation:
Manual weeding is effective and should
be done at monthly
interval. Control of weeds by using
chemicals is also found effective. A
pre-emergent treatment of
Gramaxone (@ 3 litres /
ha) followed by three
post- emergent sprayings at
intervals of 110 days in
between the rows keeps the crop weed
free. Application of Atrazine @ 3
kg/ha in 1000 litres of water as a pre-emergent
weedicide also keeps the plots weed-free.
Atrazine @1.0-1.5 kg /ha in 1000 litres of water sprayed
immediately after planting of
bulbs, significantly reduces th weed
population. Mulching the plots with
strips of black polythene, dried grass
and chopped straw is effective in
controlling weeds. Hoeing between plants
at regular intervals is helpful in
loosening the soil and uprooting weeds. Earthing - up enables the spikes to grow erect, despite strong
winds and rains. Earthing
up to 10-15 cm height is done when
plants are 15- 20 cm high. The
flower-spikes should be supported by
stakes after about 2 1/2 months of
planting. Staking with bamboo
or wooden sticks is done in beds
and string or rope may be tied in
three rows along the plant-rows to avoid
lodging of plants.
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| Flowers are ready for harvesting |
Tuberose flowers are ready for harvesting after 100-120 days of
planting. Harvesting is done in cool hours either in the morning or evening.
Local market: Cut
flowers are harvested when lower one pair of flowers is fully open
Distant market: Lower
pair of flower buds has
just burst
Loose flowers: Fully/
half open flowers
Grading: Tuberose cut flowers
are graded according to spike length, rachis length and number of flowers per spike.Loose
flowers is graded according to flower size.
Packaging: Cut flowers are
marketed in bunches of 25, 50 or 100 and these bunches/bundles are packed in bamboo baskets, card board cartons/containers and are transported vertically.
Loose flowers are packed in bamboo baskets or gunny bags
or polythene bags lined with newspaper.
Bulb Harvesting
Harvest bulbs after 40-50 days of
flowering or
foliage start turning yellow. Treat bulbs before storing.The bulbs are graded into two sizes as
small less
than 1.5 cm in diameter and large more than 1.5 cm in diameter.Tuberose
bulbs are harvested/lifted after 2-3 years.