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THE tuberose, a native to Mexico, belongs to the family Amaryllis and is commonly known as lily. It has long been cherished for aromatic oils extracted from its fragrant white flowers.
It is a popular cut flower, not only for use in arrangements, but also for individual florets that can provide fragrance to bouquets and boutonnieres. Among flowers, lily occupies a selective position because of its beauty, elegance and sweet, pleasant fragrance.
Lily blossoms at night and is recognised by its captivating smell. Besides oil extraction, the flowers are also used in making garland bouquets.
It has gained considerable importance among growers of tropical regions of Southeast Asia. It is now-a-days, being commercially grown in big areas. It has great economic potential in the cut flower market and in essential oil industry. It grows in elongated spikes that produce clusters of white flowers that are 5-6 cm long and have a characteristic bending. The flower spikes are up to two feet in height. Tuberose flowers bloom from the bottom toward the top of the spike. The flowers remain fresh for a long time and are suitable for long distance transportation.
Climate: The plant is tropical to semi-tropical. Basically, it needs warmth, sunshine, high relative humidity, well-drained soil, and even moisture. The commercial cultivation of tuberose is mainly confined to warm, humid areas with average temperature ranging between 18 to32 degrees C. The ideal temperature for plant growth ranges between 26 and 30 degrees C. The tuberose needs a long growing period in order to blossom in early to late fall. The spike production, along with the quality of flowers declines to a great extent during December –January except in “double varieties” of tuberose.
Soil type: The plant can be successfully grown on a wide range of soils, even in soils affected by acidity or alkalinity to some extent. The plant is very sensitive to water-logging which damages the root system and affects the plant growth. Loam and sand loam soil having pH range of 6.5 to 7.5 with proper aeration and drainage are considered best for tuberose cultivation. The soil should be rich in organic matter and retain sufficient moisture for proper growth. The soil should be thoroughly prepared for achieving desired results. Deep ploughing is necessary for bringing to a good tilth and for the eradication of weeds. About 12-15 tones of FYM/ha should be incorporated into soil three weeks before planting.
Planting time: Tuberose can be commercially grown throughout the year but highest yield is obtained from February through October. However, best time for planting is from second to last week of March, where as April-May is the appropriate time for hilly areas.
Propagation: Propagation of the plant can be done by means of seeds and bulbs. Vegetative propagation is commonly practiced and is desirable too, because such plants produce better flowers within a short period after planting. Vegetative propagation is done by means of bulbs. The bulbs of 2-3 cm wide are suitable for propagation. Planting of fresh bulbs produce less number of flowers hence, bulbs should always be kept in store for a month or more to ensure better production of flowers. Larger bulbs result in early flowering and higher yields. The bulbs are cut vertically in to 2-3 sections in such a away that each segment contains a bud for germination. The bulbs should be planted 4-5 cm deep in beds and soil moisture should be maintained after planting of bulbs before monsoon starts.
Varieties: The main varieties are ‘single’ with one row of corolla segments and ‘semi double’ with two to three rows of segments. The commercial varieties of single tuberose are Calcutta Single, Mexican Single, and Royal Rehab etc.
Requirement: During preparation of the soil, a basal application of farm yard manure (FYM) at the rate of 12 to 15 tones per hectare should be done to ensure better growth and flowering. Besides, application of FYM in tuberose requires good quality of major and micronutrients. A fertiliser mixture containing six gms of urea, 16gms each of single super phosphate (SSP) and muriate of potash per square meter gives satisfactory growth and flowering. The above mixture should be applied in two equal doses – the first dose should be applied before plantation and the second one, four weeks after sprouting of the bulb. The foliar feeding of K and N produces more number of flowers with better quality.
Weeding: Weeding is carried out after a fortnight, especially in the initial stage of the bulb sprouting and the growth of plants. Hand weeding is eco-friendly but extensive. For chemical control; Atrazine can be applied.
Mulching: It is primarily carried out for conserving soil moisture and checking weeds in the field. Black polythene and gliricidia leaves are most suitable mulches for tuberose cultivation. About 5kg green leaves of gliricidia are sufficient for 1m x 1m plot to harvest a bumper yield and quality of flowers and spikes. Paddy straw can also be used for mulching in tuberose to conserve soil moisture and to reduce the weed population.
Water management: Soil moisture is an important factor affecting the growth, flowering and bulb yield of tuberose. Field should be irrigated before planting of bulbs and further irrigation should be avoided until the sprouting of bulbs. The crop should be irrigated at weekly interval in the absence of rainfall. Mulching reduces the water requirement by minimising the evaporation losses. However, irrigation should be avoided at the maturity stage of bulbs during December-January.
Diseases and insect Pests
Stem rot: The soil borne diseases can be identified with symptoms like appearance of prominent coarse mycelial masses on the leaf surface at or near the soil level. Infected leaves loose green colour due to rotting, which extends to the whole leaf and detaches the affected leaves from the plant. The infected plants should be burnt immediately to check further infection.
Flower bud rot: It is also a bacterial disease. The disease appears mainly on young flower buds and results in dry rotting with brown scorched necrotic discolouration of peduncles. In the advanced stage, buds become shrivel and dry. This disease is mainly spread by thrips. Destroy or burn the infected plant debris to check further infection and adopt remedial measures to control the thrips.
Thrips: Thrips feed on leaves, flower stalk and flowers. They suck sap from these parts and ultimately damage the whole plant. Some times they are associated with a contagious disease known as bunchy top where the inflorescence is malformed. Thrips can be managed by spraying endosulfan twice at 10 days interval.
Harvesting and packaging: Tuberose is harvested by cutting off the spikes from the base for decoration or the individual flower is picked from the spike for making garlands. Tuberose flowers are very sensitive to the stresses of storage and transportation, particularly at warm temperatures. The picking of flowers should be done in the morning; harvesting of flowers in the evening and marketing them next morning. The flower spike should be cut off and placed immediately in cold water. Loose flowers are packed in bamboo baskets, covered by cloth. The spikes are graded as per length of the spike, length of the flowering zone and quality of individual flowers. To avoid any loss during transition, the flower bundle should be wrapped in soft tissue paper, polyethylene or card board boxes. Preservative can be used to increase the longevity and the keeping quality of tuberose flowers.
Flower yield: Flower yield varies with variety, plant density and bulb size at planting time and crop, management. A two-year experiment with the ‘single’ variety of tuberose recorded a flower yield of 3, 75,000-5, 50,000 spikes/ha during the first year.
Harvesting and yield of bulbs: Harvesting of tuberose bulbs at the proper stage of maturity is important for storage of bulbs and their growth. The bulbs reach maturity when the flower is over and the plant growth ceases. At this stage, the old leaves become dry, plant growth ceases and bulbs are almost dried. About 100 quintal of bulbs can be harvested from one hectare of land.
