Sunday, 20 April 2014

Production Technology of Tuberose : Horticulture



      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

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