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 areas of the Pakistan.
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.
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.
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.
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.
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.
Propagation by bulbs
This is the most common method practice 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.
Cultivation
The various cultivation practices for the growth of
tube rose are described here.
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.
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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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 gonorrhea.
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