I. Introduction
Tube rose is a single species of
half-hardy, bulbous plant native to Mexico, suitable for growing in a
green-house or sometimes in sunny, sheltered positions out-doors, during
summer. The tuberose occupies a very selective and special position among the
ornamental bulbous plants for its beauty, elegance and sweet pleasant
fragrance. It has a great economic potential for cut-flower trade and essential
oil industry. Due to their great demand, it is currently cultivated in most of
the tropical and sub-tropical countries of the world.
Tuberose is a native of Mexico. In India, tuberose is
commonly known as Gulchari and Galshabbo in Hindi, Rajanigandha in Bengali,
Sukandaraji and Nelasanpengi in Telegu, Nilasompangi in Tamil and Sugandharaja
in Kannada. At present the total area under tuberose cultivation in the country
is estimated to be about 20,000 hectare.
II. Morphology and Classification
Tuberose is a half-hardy, bulbous perennial
perpetuating itself through the bulblets. Bulbs are made up of scales and leaf
bases and the stem is a condensed structure which remains concealed within
scales. Roots are mainly adventitious and shallows. The leaves are long,
narrow, linear, grass-like, light green, and arise in rosette. The flowers have
a funnel shaped perianth and are fragrant, waxy white, about 25 mm long, single
or double and borne in a spike. The terminal flower spikes arising from the
bulb produce flowers for a number of days. Stamens are six in number, anthers
dorsifixed in the middle, ovary 3 locular, ovules numerous and fruits are
capsule.
The determination of the family to which the genus
Polianthes belongs, had long been a matter of difference of opinion among taxonomists.
Ultimately ,the genus was placed in the family Amaryllidaceae.
III. Species and Cultivars
The various species and cultivars of tuberose are
mentioned here.
A.
Species .
1.
Polianthes tuberosa
It is an erect herb, 60-120 cm high with stout and
short bulbs; leaves basal, 6 to 9 in number, 30-45 cm long, about 1.3 cm wide,
linear, bright green, reddish near the base, flowers funnel shaped, waxy white,
the tube bent only near the base, filaments attached on upper part of corolla,
fragrant in long terminal racemes.
2.
Polianthes polustris
This white flowering species was described as
having bulbs which are oval to oblong, stems approximately 38 cm high, erect
and glabrous, several basal leaves, narrow with parallel veins, stems with leaves
or bracts reduced in size near the terminal end of the stem; flowers in 3 to 5
pairs arising from single bracts.
3.
Polianthes durangensis
The bulbs are small in this species and the flowers
arranged in one to six pairs are all sessile, erect at first becoming curved
and purplish with age.
4.
Polianthes montana
This is another species with white flowers. In this
species the bulbs are oblong, the stem long and tender, and possessing 12 pairs
of flowers all with pedicels. The flowers are short with lobes small, erect and
rounded.
5.
Polianthes longiflora
This is a tall species with flowers in three to five
pairs. Perianth are white tinged with purple colour.
6.
Polianthes platyphylla
In this species the flowers are white tinged with red.
The florets are arranged in four to seven pairs with tube of the floret bent at
the base and with short, rounded lobes. The presence of the red colour, the
short lobes and the curvature at the base of the penanth suggest the natural
crossIng of the wild red and white species of tuberose.
7.
Polianthes graminifolia .
The bulbs are long and tuberous. Stems are slender,
densely hairy below and glabrous above. Leaves are long and grass-like. The
flowers are in 8 to 15 pairs, the lower ones often on peduncles, deep red, bent
downward near the base and the filaments are slender and attached low down in
the tube.
8.
Polianthes geminiflora
Flowers are light orange-red in colour and arranged in
pairs of 6 or more. The Perianth is similar to that of the species P.
graminiflora and bent down sharply at the base. Lobes are short, broad and
rounded at the tip.
9.
Polianthes gracilis
This species is supposed to be Mexican and is
distinguished by slender habit and narrower leaves. Perianth tubes are long and
slender Possibly this was the original form of P. tuberosa.
10.
Polianthes pringlei
Plants of this species have small bulbs and smooth
stems. Flowers are sessile, in pairs of 3 or 4, curved, fragrant and white in
colour which changes to slightly purplish on drying.
B. Cultivars
There
are three types of tuberose:
i.
single with one row of corolla segments;
ii.
semi-double bearing flowers with 2-3 rows of segments;
iii.
double having more than three rows of corolla segments.
Sometimes
cultivar names are given after places like Calcutta Single and Calcutta Double.
Calcutta Single and Mexican Single have
been identified as promising ones for large scale cultivation.
IV. Climate
Tuberose grows in mild climate without extremes of
high or low temperatures even though it can be grown under a wide range of
climatic conditions. The commercial
cultivation of tuberose is mainly confined in warm humid areas with average
temperature range from 20o to 35oC. For its luxuriant
growth, it requires high humidity and a temperature around 30oC.
Temperature above 400C reduces the spike length and quality of the
flowers. Very low temperature and frost also damage the plants and flowers.
Tuberose grows well in sunny situation.
V. Soil
The tuberose grows in a wide range of soils. Loam and
sandy loam soils having a pH range from 6.5 to 7.5 with good aeration and
drainage are considered suitable for its cultivation. The soil should be rich
in organic matter and retain sufficient moisture for proper growth. For
cultivation in pots, a mixture of garden soil, FYM and leaf mould in the
proportion of 2:1:1 should be used.
VI. Propagation
Tuberose is mainly propagated vegetatively by means of
bulbs. Seeds, if produced, are difficult to germinate. Propagation may also be
done by the division of bulbs. To get virus-free material or for a very rapid
multiplication, the propagation is done through tissue culture.
A. Seed propagation
Under favourable climatic conditions seeds are sown in
well prepared growing medium containing leaf mould and garden soil in equal
proportion. Moisture and temperature have a marked effect on germination. The
soil temperature of 80°F (26.6°C) is supposed to be optimum. The bed for
raising seedling should thoroughly be prepared by digging and sufficient
quantity of FYM is to be mixed before sowing. The seeds are sown in rows 10 cm
apart and 1.5 cm deep in heavy soil and 2.0 cm in light soil. Moisture can be
maintained by spreading the mulch on the bed. Seeds start germinating within 10
to 15 days after sowing. After the seedlings have attained a good growth, these
are transplanted in pots or ground where they are allowed to grow.
B. Vegetative propagation
The tuberose can also be propagated vegetatively by
the following methods.
1. Propagation by bulbs
This is the most common method practised commercially
for the multiplication of tuberose. Care should be taken in the selection of
suitable bulbs. Spindle-shaped bulbs free from diseases and having an average
diameter of 1.5 cm or above should always to preferred to conical or flat
bulbs. The maximum production of bulbs can be obtained by planting the early
and to grow as late as possible.
2. Propagation by division
Another method of propagation is by using bulb
segments. The success, depends on the size of the bulbs and only the segments
from large bulbs (2 cm or more in diameter) regenerate well. Bulbs are cut into
2-3 vertical sections, each containing a bud and a part of the basal plate.
Each of these sections is treated with fungicide and planted vertically in a rooting
medium with their tips just showing above the surface. A moderately warm
temperature, slightly higher than for mature bulbs should be maintained. New
bulblets along with roots develop from the basal plate. At this time they are
transferred to the ground to continue growth.
C. Micropropagation
The conventional method of propagation through bulbs
is rather slow to meet the growing demand and, therefore, clonal propagation
through tissue culture may be utilized for rapid and large-scale
multiplication.
VII. Cultivation
The various cultivation practices for the growth of
tube rose are described here.
A. Site selection
For optimum growth and high yield of flowers it is
preferable to choose a place having plenty of sunlight. A little shade towards
the later part of the afternoon is desirable in hot summer of there is too much
shade. Tuberose is sensitive to wet feet, drainage should be good, water-
logging damages the root system and affects the growth and flowering.
B. Soil preparation
Land preparation is very important for the cultivation
of tuberose. The field should be worked deep to a good tilth and properly
manured. If the soil is not thoroughly prepared and contains soil clods or
undecomposed organic matter, bulb production is affected and it also reduces
the yield and quality of flowers. Well rotten cow dung or farmyard manure @ 50
tonnes/ha, should be incorporated with the soil about a month before planting.
Care should be taken to make the land free from weeds.
C. Bulb selection and planting
Selection of good planting material'is necessary for
obtaining higher yield and good quality of flowers.The bulbs before planting,
should be treated with fungicide, and Blitox may be used for this purpose. They
should carefully be placed upright by land and covered with soil. For pot
cultivation, 2-3 bulbs are planted in the centre of a 20 cm pot.
1.
Bulb size, depth and planting time
In general, bulbs having diameter having 2.0 to 3.0 cm
are suitable for planting. It has been observed that planting of bulbs having
2.6 to 3.0 cm recorded the highest yield of spikes (15.1 Iakhs/ha) and flowers
(30.1 tonnes/hectare).
Planting depth also influences growth and production
of flowers. It may vary from 4.0 to 7.0 cm depending on the size of the bulb. The
bigger is the bulb, the more is the depth.Planting of bulbs at greater depth
delays the appearance of shoots. In sandy loam soil, planting of bulbs at the
depth of 6.0 cm is recommended.
Tuberose is generally planted in February-March in the
plains and in April-May in the hills. On a medium fertile clay soil, the best
time for planting was reported between 14 and 29 June. Sequential planting may
be practised to obtain flowers almost throughout the year, if the temperature
is not very low in the winter months.
Replanting
is necessary after 3 years
2.
Planting distance
Plant density influences the yield and quality of
flowers and bulbs obtained per unit area. Higher plant density has been found
to produce greater yield of spikes, flowers and bulbs. The planting distance
varies in different regions
D. Irrigation
The frequency of irrigation depends upon soil type,
stage of growth and weather conditions.
The tuberose fields should be irrigated at interval of 10-15 days, if the
weather is dry.
It has been suggested that during summer months (April
to June) the crop should be irrigated at weekly interval and during winter at
10-day interval.
VIII. Manuring and Fertilization
The requirement of manures and
fertilizers for tuberose vary with climatic conditions and soil types. During
the preparation of soil a basal application of leaf mould, farmyard manure or
cattle manure @ 20 to 50 tonnes/ha.
High dose of, N and P promotes leaf and bulb formation
in tuberose. The effect of K has been less pronounced than N and P. The plants
treated with low dose of N and P shows growth inhibition and fails to flower.
The flower quality is also affected adversely. The
effect of deficiency of various elements is given below.
Effect of fertilizer deficiency
|
Sl.No
|
Fertilizer element
|
Deficiency symptom
|
|
1
|
Nitrogen
|
Reduction in number of
spikes and number of flowers per spike; typical pale green foliage
|
|
2
|
Phosphorus
|
Dark green upper leaves and
purple colouration in lower leaves;
reduction in growth and flowering
|
|
3
|
Calcium
|
Cracking of the spike, bud
rot in case of acute deficiency
|
|
4
|
Magnesium
|
Interveinal chlorosis of
older leaves
|
|
5
|
Iron
|
Interveinal chlorosis of
new leaves
|
|
6
|
Boron
|
Cracking of leaf margins,
deformed leaves and stunted inflorescence
|
|
7
|
Manganese
|
Yellowing between the veins
of lower leaves
|
IX. Growth and Flowering
In the vegetative stage the bulblets grow and attain
their maximum size. The subsequent reproductive stage includes the initiation
of flower differentiation of floral parts, elongation of the flowering shoot
and finally flowering and sometimes seed production.
Tuberose normally begins to flower in 80 to 95 days
after sprouting. It flowers profusely during summer and rains
(April-September). In the hills it flowers in May-August, while in milder
climate this flowers well throughout the year.
A. Environmental factors
The various environmental factors affecting the growth
and flowering of tuberose are mentioned here.
1.
Temperature
Temperature is the most important factor affecting
growth and initiation and subsequent flower development. High (40°C) as well as
low temperature (10°C) reduce spike length, weight and quality of tuberose
flowers. The optimum temperature range for growth and development is 20 to
30°C.
Storage temperature also influences the sprouting of
bulbs after planting and subsequent growth and flower production. Pre-plant
storage of bulbs at 10°C for a period of 30 days was found to improve the plant
growth and increase yield of spikes and flowers.
2.
Light
Although tuberose is not strictly photosensitive. A
day length of about 16 hours promoted growth and flowering.
Low light intensity adversely affects flowering,
therefore, in short-day conditions i.e. winter growing, supplementary light may
help producing better blooms.
B. Role of growth substances and other chemicals
Growth and developmental behaviour of bulbous plants
is also regulated by an interaction of
several endogenous growth hormones like gibberellin, auxin, cytokinin and
abscisic acid (ABA). They play a major role in directing the movement of
organic metabolites and in establishing sinks.
Application of certain growth substances has been
found to influence the growth and flowering of tuberose.
X. Weed Control
Weeds become serious problem in the cultivation of
tuberose. If these weeds are not removed in time, growth and productivity will
be markedly reduced. Generally, after each irrigation, weeding is done. Hoeing
between plants is also necessary to loose the soil and destroy the weeds.
Pre-plant application of Atrazine
(2-chloro-4-ethylamino- 6-isopropylamino, 1,3,5. triazine) @ 3.0kg ai./ha was
also found very useful for the reduction of weed population in tuberose field
resulting in the highest yield (10.2 tonnes/ha) of good quality flowers.
XI. Disease Control
Tuberose is hardy and there are no serious diseases
and pests posing problems for the cvItivatiqn of this crop. However, it is
attacked by some diseases and pests which are described here.
1.
Fungal diseases
The important fungal diseases affecting Tuberose
are mentioned here.
a.
Stem rot
This disease is caused by a fungal
organism known as Sclerotium rolfsii.
Symptoms
.
The disease symptom is preceded by the appearance of
prominent coarse mycelial masses on leaf surface at or near the soil level.
Soon the infected spots lose green colour due to rotting which extend and cover
the whole leaf and become detached from the plant. More or less round
sclerotia, brown in colour, are formed on and around the infected leaves. As a
result the infected plants become weak and flowering shoots in case of severe
damage.
Control
The disease can be controlled by soil application of
Brassicol (quintozene) or Zineb at 3-week interval.
b.
Botrytis spots and blight
This disease is caused by Botrylis elliptica.
This organism seriously damages the leaves. .
Control
it can be controlled by spraying the
plants with
i.
ammoniacal copper @ 2gal/l00 gal. of water,
ii.
sodium salt of O-hydroxydiphenyl, 1:200.
The
treatment should be repeated at fortnightly interval.
2.
Bacterial disease
The important bacterial diseases affecting Tuberose
are mentioned here.
a.
Flower bud rot
This disease is caused by Erwinia spp.
Symptoms
The disease appears in dry rotting of the buds with
brown scorched necrotic discolouration. At later stage, buds shrivel and become
dry.
Control
The disease can be controlled by segregation of plants
and application of corrosive sublimate (1 part in 1000).
3.
Bunchy top disease
A contagious disease known as bunchy top causes
mal-formation of the inflorescence like a ball. Control of thrips which are
associated with this disease, checks the malady.
XII. Pest Control
The important pests affecting the tuberose are
mentioned here.
1.
Grasshopper
The insects feed on young leaves and flower buds.
Control
Spraying the plants thoroughly at fortnightly interval
with 0.1 % Roger or 0.1 % Malathion keeps away these pests.
2.
Weevil
The adult weevils which become active in darkness
damage the shoots and feed on the leaves. The larvae feed on roots and tunnel
into the bulbs.
Control
Larvae can be controlled by dressing the soil with BHC
dust before planting and working it into the top few inches.
3.
Aphids
Aphids, very small in size, feed on the flower buds
and growing points.
Control
These pests may be controlled by spraying 0.1 %
Malathion at 10-day interval.
XIII. Harvesting and Yield
The bulbs reach maturity when the
flowering is over and plant growth ceases. At this stage, the old leaves become
dry before digging out the bulbs. The leaves are cut at the ground level and
bulbs are taken out of the soil.
Tuberose is harvested by cutting the spikes from the
base for table decoration or the individual flower is picked from the spike for
making garlands and other floral ornaments.
Picking of flowers should be done in cool hours of the
day either in the morning or evening. Four to five persons can harvest about 60
kg flowers in 2 to 2.5 hours.
The flower spike for table decoration should be cut
when the first pair of flowers fulIy open, with a sharp knife and placed
immediately in water.
Yield
Flower production varies with cultivars and depends
upon bulb size at planting time and density of planting and cultural practices
adopted. Flower yield of 12,000 kg/ha was recorded by using FYM alone, while
fertilization with N and P increased the yield to 29~951 kg/ha. Average yield
of 4.8 to 9.6 tons in the plant crop, 8.9-12.1 tones/ha in the first ratoon
crop and 4.2-5.4 tones/ha in the second ratoon crop, depending on the size of bulbs
were recorded.
XIV. Post. Harvest Handling and Packaging
Loose flowers are packed in bamboo baskets holding
about 10-15 kg flowers and are transported to the nearby wholesale market where
they are sold by weight. The flowers spikes are graded according to length of
spike, length of flowering zone and quality of individual flower and then
bunched in round bundles each having about 100 sticks. The stem portion of the
bundles is wrapped in wet newsprint sheets. To avoid damage of the flowers and
buds, the whole bundle should be wrapped in soft, white tissue paper or
polythene. These bundles may be packed in the card-board boxes and shipped by
air to reach the destination quickly.
XV. Vase Life
Little information is available regarding the
longevity and keeping quality of tuberose flowers. A preservative solution
containing benzimidazele, SADH, ascorbic acid, sucrose and 8-HQC in appropriate
proportion was found useful for improving the opening of flowers on tuberose
spikes and enhancing the vase-life of flowers.
XVI. Storage of Bulbs
The soil adhered to the clumps is removed and the
offsets are separated by rubbing off. Loose scales and long roots should be
removed and bulbs are graded into different groups depending upon the size of
bulbs (diameter). They are stored separately in a cool, dry and shady place.
During storage the bulbs should be stirred every few days to prevent and check
the spread of mould and rot. Storage for 4-6 weeks is necessary before the bulbs
are ready for planting.
XVII. Importance and Uses
Tuberose has gained considerable importance and it is
cultivated commercially for its varied uses.
1.
It can successfully be grown in pots, beds and borders.
2.
The flower remains fresh for a long time and stands long distance
transportation and fills a useful place in the flower market.
3.
Flowers are used for artistic garlands, floral ornaments, bouquets. The long
flower spikes are excellent as cut-flowers for table decoration.
4.
Flowers are the source of the tuberose oil.
5.
The natural flower oil of tuberose remains today one of the most expensive of
the perfumer's raw material.
6.
Fragrant flowers are added along with stimulants or sedatives to the favourite
beverage prepared from chocolate and served either hot or cold as desired.
7.
The bulbs are considered diuretic and emitic. They are rubbed with turmeric and
butter and applied as a paste over red pimples of infants. Dried tuberose bulbs
in the powdered form are used as a remedy for gonorrhoea.
XVIII. Reference
Bose,
T. K. and L. P. Yadav. 1989. Commercial Flowers. Volume-1. Naya parkas.
Calcutta. India
Presented
and prepered by:
Md. Rafiqul
Islam Shuvo
B.Sc.Ag.(Hons.)
, PSTU
MS in
Horticulture, BAU
www-agricultureinfo.blogspot.com
shuvo_ag10@yahoo.com
