Tuberose

Tuberose is famous cut flower. Botanically it is called Polianthes tuberosa L and belongs to family Asparagaceae. The origin of tuberose is Mexico from there it spread to other parts of world during the 16th century. Tuberose has occupied a special position to flower loving people because of its prettiness, elegance and sweet pleasant fragrance. In essential oil industry and cut flower trade tuberose has great economic potential Tuberose flower remains fresh for longer time and has got useful place in the flower market.  The long vase life of tuberose is used for cut flower purpose it is grown in subtropical areas

Tuberose flower is spike type and its floret is funnel shaped. It has waxy appearance. Flowers are white in color usually bloom in mid-summer to winter. Flower blooming start from bottom to top on spike. Flowers consist of 6 petals 6 stamens 6 ovaries. Tuberose extract used in perfume. There are up to 30 florets in one spike and the length of spike varies between 14 and 28 cm, depending upon the corm size when planted. The spikes are best for vase and other floral decorations. The spikes last long in vase for 10-15 days

Tuberose grows better in temperature range of 20-30°C with no shading or supporting structures for the plant. Flowering of tuberose vary according to the temperature range. The rate of first floret emergence is directly influenced by the more air temperature. Tuberose can be grown in wide range of soils. Loam and sandy loam soil is best having pH range from 6.5 to 7.5, proper aeration and drainage is essential for better production of cut flowers and corms. The soil must retain sufficient moisture    

Warm temperature promotes flower initiation while water increase quality and yield to maximum level, hence irrigation is required for best quality flowers. In water stress situations the flowering period, flower quality and yield of corms reduced                               

In case of weed control hand weeding is practiced by farmers, but pre and post emergence herbicides can also be used. Number of pests including nematodes, rodents attack tuberose. In summer season insects such as aphids, spider mites and thrips affect tuberose. Under cool, moist growing conditions fungal and bacterial diseases become common and it is recommended to treat bulbs and drench the soil with fungicides at planting

As tuberose is a delicate flower and sellers and consumers are interested in extending its vase-life, this necessitates improving its postharvest life. Tuberose cut flowers are sensitive to ethylene that reduces the postharvest life. As tuberose is very important for perfume industry so more researches have been done on the species Polianthes tuberosa L. Various studies conducted on tuberose postharvest life, the study showed that bacterial contamination is one of the most important factors in reducing postharvest life of cut flowers with the negative impact on process of respiration, photosynthesis and water uptake. With increasing evaporation water imbalance occur and indirectly stimulates ethylene synthesis and finally shortens postharvest life of tuberoses. By using antimicrobial compounds, such as aluminum sulfate to increase postharvest life of cut flowers like tuberose. It has been shown that the use of calcium, aluminum, boron, copper, nickel and zinc salts extends the vase life of cut flowers

Plant spacing is important factor that affect growth and production of tuberose. Tuberose is bulbous plant and for its commercial production it is propagated through mother corms and daughter corms. Corms spacing depends upon types of soil and irrigation method. Wider spacing is required in case of sandy soil than heavier soils. Also close planting causes competition for nutrients and light that ultimately reduces growth, yield and quality. Micro-organisms growth also encouraged by close planting and thus results in pathogenic diseases. In addition,  maximum obstruction in field during cultural practices like weeding, hoeing harvesting flowers for cut flower marketing are also caused by close planting. Consequently, the cost of production will be increased

Corm size is another important factor considered for maximum production of tuberose on commercial scale. Small sized corms are economic but they may not fulfill the present demand of cut flowers and corm production as they may have low emergence percentage due to insufficient carbohydrates. While large sized corms have economic problems. So wider spacing and large sized corms both factors results in loss of inputs like soil, nutrients and water

Description

Tuberose is half-hardy, perennial, bulbous plant. Bulbs are made of scales and leaf bases and stem remains concealed within scales. Roots are mainly adventitious and shallow.The tuberose grows 18-24 inches in height with lots of long bright green slender leaves clustered at the base of the plant that taper towards the top, and smaller sized leaves that grow on the flower's stalks. The flowers grow on elongated spikes up to 18-20 inches in height, producing clusters of fragrant waxy white flowers that bloom successively from the bottom towards the top of the spike. Each spike easily contains more than 50-60 flower buds. The flowers emit a strong scent that gets stronger during nighttime. The flowers are primarily night blooming, but bloom under the hot sun too.. Flowers have a funnel shaped perianth and are fragrant, waxy white, about 25 mm long. Stamens are six in number, ovary 3 locular, ovules numerous and fruits are capsule.

Propagation

Tube roses are easy to grow and can be easily propagated through bulbs and division of rhizomes

  Importance

They are used for making artistic garlands, floral ornaments, bouquets and buttonholes. The long flower spikes are excellent as cut flowers for table decoration.

The flowers emit a delightful fragrance and are the source of tuberose oil which is used in high value perfumes and cosmetic products. Furthermore, fragrant flowers are added along with stimulants or sedatives to the favourite beverage prepared from chocolate and served either cold or hot as desired. The bulbs are reported to contain an alkaloid lycorine, which causes vomiting. The bulbs 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. In Java, the flowers are eaten along with the juices of the vegetables

Climatic Requirement

In India, commercial cultivation of tuberose is confined to warm humid areas with average temperature ranging from 16° to 30°C. Tuberose is also grown in hilly areas up to 1200 to 1500 meter height. Moist or humid and temperature are the two main factors responsible for the increasing or decreasing the production. Temperature over 40°C leads to decrease the length of spike and quality of flowers. Likewise, fall in temperature or incidence of frost damages the plant and the flowers. It prefers sunny situation and should not be grown on shady or semi-shady situation which drastically reduces the flower yield.

Tuberose although not strictly photosensitive, long-day exposure promotes vegetative growth as well as early emergence of the first flower spike and also increases the length of flower spike. A day length of 16 hours promoted growth and flowering.

Soil Requirement

Tuberose should be grown in well-drained place, as it cannot tolerate water logging even for a short period. Tuberose is grown in wide range of soils from light sandy to clay soils including those affected by salinity and alkalinity conditions. Fertile loamy and sandy having pH range from 6.5 to 7.5 with good aeration and drainage are ideal for tuberose cultivation.

Field Preparation and Sowing

            The land was first open by ploughing with power tiller and then it kept open to sun for seven days. Then it was prepared by cross ploughing and laddering. The weed and stubble removed after each laddering. All the clods were broken and the soil was brought in good conditions. Recommended dose of fertilizer was added during the final land preparation. The nitrogen was applied in two split doses.

Planting of bulbs

Corms of tuberose were purchased from store and were planted on 18th February 2013 at the following four spacing of 5cm, 10cm, 15cm and 20 cm. Three different corm sizes i.e. small size corm with 1.5-2.5 cm, medium size corm 2.6-3.5 cm and large size corm of 3.6-4.5 cm diameter were used. The experiment was conducted in University of Agriculture, Horticulture research farm. Corms were planted at a depth of 10 cm and the row spacing was 20 cm.

Seed treatment

These bulbs are first thoroughly cleaned and treated with Bavistin (0.2%) for 30 minutes. 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 to improve the plant growth, increased spike and flower yield. Pre-planting treatment of bulbs with GA3, etherel or thiourea promoted early appearance of flower and produced highest number of longer spikes with maximum number of florets. Season: Planting done in the month of March-April in plains and April-May in hills.

Nutrient Management

In general, a basal dose consisting of FYM @ 10 kg/sq m, single super phosphate and murate of potash each @ 80 g/sq m, 10-15 days prior to the planting of bulbs is recommended. Nitrogen @ 15 g/sq m should be applied in three split doses. First one-third dose is given at the time of planting of bulbs, second at 60 days after planting and the third when flowering starts.

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. During summer, irrigation should be given at weekly interval or even earlier in case soil dries out and during winter at 10 days interval.

Weed Management

Manual weeding is effective and should be done at monthly interval.

For chemical weed control, Atrazine @1.0-1.5 kg /ha in 1000 litres of water is sprayed immediately after planting of bulbs.

Pest Management

The important insects are thrips, aphids and weevil. Thrips and aphids are controlled by the spray of Rogor or Metasystox @ 1.75 to 2.0 ml/litre. The weevils can be controlled by the spray of Thiodon @ 2.0 mg/litre.

Bud borer (Helicoverpa armigera) This can be controlled by the spray of endosulfan (0.2%), monocrotophos (0.2%) or Thiodan (0.5-0.8%).

Harvesting

Flowering of tuberose starts 80 to 100 days after planting and flowering time is July onwards. Tuberose flowers all the year round. Spikes are harvested at bud-burst stage preferably in the morning before sunrise or late in the evening by clipping with a sharp knife or secateurs that gives a clean cut. About 4-6 cm basal portion has to be left to allow the growth of bulb. The lower portion of the cut spikes immediately after harvest, are to be immersed in water for prolonging life of spikes. For loose flower purpose individual flowers are plucked early in the morning.

                                                                                   Lifting, Curing, and Storage of Bulbs

Bulbs reach maturity at the cessation of flowering when the leaves become yellow and dry during winter (February-March) in North India. At this stage, irrigation is withheld and the soil is allowed to dry. The leaves are cut off at the ground level and the bulbs are dug out. After digging, the bulbs are lifted out and the adhering earth shaken off neatly and thoroughly. The offsets are then separated out by hand, which are used as seed-stock for the next season.

The bulbs are the graded based on the size into mature (> 1.5 cm diameter) and immature (< 1.5 cm diameter). Cleaned and graded bulbs are placed on sheives to dry or cure. To hasten curing, artificial heat of 27o to 35o C may be applied. The bulbs must be stirred or have their position changed every few days to prevent fungal attack and rotting

Post Harvest Activities

Grading

• The flower spikes are graded according to the stalk length, length of rachis, number of flowers per spike and weight of spikes.

• Straight and strong stem of uniform length and uniform stage of development are preferred.

• Flowers should be free from bruises and diseases and pests.

• Florets are graded according to their size for loose flowers.
Packing and Transport

For room decoration, long spikes are preferred and are sold in bundles. Each bundle contain 100 spikes. To avoid damage of the flowers and buds, the whole bundle should be wrapped in soft, white tissue paper or polythene. These bundles are packed in rectangular bamboo baskets lined with Hessian cloth.

For long distance transport, they are packed in square boxes or airy baskets but packing in cardboard boxes is more suitable which can be easily transported by rail, bus or by truck. Loose flowers are packed in bamboo baskets holding about 10-15 kg flowers and the baskets are covered with muslin cloth and are transported to the nearby wholesale market where they are sold by weight.

Extraction of Oil and Quality Control

The flower oil is extracted by effleurage and solvent extraction with petroleum ether. Freshly picked flowers, before they open are effleuraged. About 150 kg of flowers yield 1 kg of absolute of enfleurage which contains 11-15% of steam volatile oil. Extraction of tuberose flowers with petroleum ether yield 0.08 – 0.14 per cent of concrete. The concrete contains 3 – 5 per cent of a steam volatile oil. Out of the approximate total yield of 30,000 kg of loose flowers from one hectare, in three years, 27.5 kg of ‘concrete’ could be obtained. This concrete in turn will yield about 5.50 kg of absolute. One hectare of tuberose plantation may yield upto 12 kg of concret