It’s time to Tulip
Dr. A.V.D Dorajee Rao
R. Poornachaitanya
INTRODUCTION
Tulips are one of the most popular and widely grown flowering plants. It flowers abundantly in the vivid and vibrant spectrum and colours. It is first among bulbous ornamentals due to its attractive colours and exquisite flowers. The tulip is the national flower of Turkey. Tulips are widely cultivated for cut flower production worldwide and also grown for pot culture, in beds, borders, and formal and informal locations. They are suitable for growing in orchards, lawns, rockeries and wild gardens.
The word tulip industry is dominated by Dutch tulip growers. There is 10,000 hectare of tulip bulbs grown in the Netherlands. In India, tulips are gaining popularity among flower growers owing to the congenial climate in hilly areas. Particularly in the Kashmir valley, the production of cut flowers is increasing. Some area has been increased in Himachal Pradesh. It can also be grown successfully in other hilly parts of the country like Uttaranchal between 1300 to 3000 meters above mean sea level.
Varieties of Tulips:
There are many improved cultivars (varieties) grown throughout the world. However, there are three classes of tulips; early flowering, midseason and late-flowering types. In India, the main varieties of early flowering Tulips are; Single Early, Double Early, Duc van Tol and mid-season tulips are; Triumph, and Mendel. The late-season Tulip varieties are; Breeders, Lily flowered, Rembrandt, Bijbloemen, Double Late, Parrots, Darwin, and Darwin hybrids. Tulipa stellata and T. aitchisonii are growing wild in Himalaya regions.
ORIGIN AND DISTRIBUTION
The scientific name of this plant is Tulipa which was assigned by Linnaeus. The name tulip is derived from the Persian word toliban meaning turban, which is an apt term to describe the flower shape of certain tulips. Tulips were first seen in Turkey. One species of tulip i.e. Tulipa stellata is found wild in the mid and high hills of Himachal Pradesh and T. aitchinsonii is native to Himalayas.
CLIMATE
Tulip requires a cooler climate for cultivation. Tulip is planted in hills where night and day temperature ranges between 5-10°C and 20-25°C, respectively. Generally, 7°C night and 14°C day temperatures are optimum. The ideal temperature for floral initiation and development is between 17-20°C. Hence, tulip grows well in the hilly areas of Himachal Pradesh and Kashmir. In Kashmir, they are left on the ground year-round and the chilling requirement is itself fulfilled in the outdoors.
SOIL
Tulip flourishes in well-drained, fertile, sandy loam soil having a pH of 6-7. Soil should be low in soluble salts. Tulip cannot tolerate standing water. Bulb rot may occur in poorly drained soil. Heavy and clay soil requires the addition of sand to increase drainage.
PROPAGATION
Sexual: Seeds are sown in February in light sandy soil under warmth. These plants flower after 5 to 6 years. Seeds collected from open field conditions produce different shades of flowers.
Asexual/Vegetative:
Bulblets: The vegetative propagation is based on the production of daughter bulb offsets from the vegetative axillary buds in the axils of truncated scales. The average rate of bulblets production is 2-3 annually. After separation from parent bulbs, these bulblets are planted 7-8 cm deep in the light, rich soil on a sunny site during November.
New bulbs: Tulip plant produces 1 or 2 bulbs capable of flowering the following year while the mother bulb remains intact.
Stolons: Triploid tulips have swellings at their base which do not turn into actual bulbs but make an elongated tubular growth at the end of which a tiny bulb forms. This stolon may form in some species of tulip-like Tulipa saxatilis and T. sylvestris.
Tulip bulbs require specific low-temperature exposure for a certain duration.
LAND PREPARATION
Good depth of soil with adequate drainage is very important for its cultivation. Soil should be dug out upto 30 cm in depth. It is advisable to use well rotten compost. Botrytis blight disease may develop as a result of the use of animal manure and hence it is not recommended. If the use of manure is essential, it should be well sterilized. Compost should be properly mixed on the top soil and turned under deeply with a spade or garden fork. After proper levelling of the field, beds should be prepared by providing good drainage facilities.
MANURE AND FERTILIZERS
Low nutrition and medium EC are acceptable for tulip cultivation. Farmyard manure at 50-100 tons/ha, nitrogen at 140-150, phosphorus at 40-50, and potassium at 110-120 along with calcium at 100 kg/ha is required for tulip crop.
PLANTING
Planting time for tulips in mid-hills (1000-1800 m above mean sea level) is from October to December. In high hills (1800 m above mean sea level), it is planted from November-December to February. Planting in mid-November was found most suitable to hasten the flowering of tulips to catch up with the early market in Kashmir valley. The staggered planting at 15 days intervals ensures a regular supply of cut flowers. The bulbs having 10-12 cm circumference should be planted for cut flower production after treating them in bavistin in 0.2 per cent solution. In general, a density of 50-68 bulbs/m² is followed. Planting is done on raised beds or in-ground with a spacing of 15×15, 15×10 or 10×10 cm. About 8-9 tonnes of bulbs are required for a one-hectare area. As a general rule, planting depth should be two to three times the greatest diameter of the bulb. Larger bulbs are planted at a depth of 20 cm and smaller ones at 10 cm.
IRRIGATION
Soil media should be watered thoroughly after planting bulbs. Monitoring of moisture level of media during the rooting phase of bulbs is necessary. After leaves begin to expand, it is to be seen that the leaves do not get wet, hence overhead watering is to be avoided. It will be helpful to check the botrytis disease. Watering in glasshouse every alternate day is beneficial. In open areas irrigation should be done at weekly intervals.
CULTURAL OPERATIONS
Weed control: Crop should be kept free from weeds. Herbicides like carfentrazone, sulfentrazone and fluminoxazin reduce weed population upto 85% in tulip crops.
FORCING
Few cultivars are suitable for forcing. The bulbs are planted and allowed to root at 9°C and are then stored at -2 to -3°C for 7-8 months. On removal, they must be thawed slowly, they take 14 to 18 days to force. Such tulips are expensive because of the cost of the treatment. The storage temperature is lowered step wise from 23°C in mid-September to 17°C before starting cooling at 9°C from mid-October to mid-December. The bulbs are then planted or packed in peat in polythene covered boxes and frozen at -2°C until removed for forcing in greenhouses at 11-18°C.
SPECIAL PRE-COOLING OF TULIP BULBS
Cold treatment during greenhouse of forcing is done in the Netherlands. After flower buds have been fully formed, they are subjected to pre-cooling. Bulbs must be pre-cooled at 5°C for 12-13 weeks. The bulbs must be planted in the greenhouse directly into 20 cm raised benches or ground beds for forcing. The 5°C forced bulbs flower within 45-60 days depending upon the cultivar and species. Special precooked tulips can be made to flower on Indian plains during winter months and at present, some professional growers are producing flowers for markets. Precooling of dry tulip bulbs at -1°C may be advantageous compared with precooling at 5°C. Increasing the duration of precooling enhanced the growth of the shoots after planting, improves flower quality and reduced the number of days to flower.
DISEASES
Fungal
Fire disease: It is caused by Botrytis tulipae. The leaves prior to emergence get infected. They became stunted, malformed, distorted and fail to unroll.The bulb should be dipped prior to planting in benomyl, thiabendazole or 2 per cent formalin for 30 minutes to reduce the carryover of inoculum and subsequent production of fireheads.
Fusarium bulb rot or basal rot: The disease is caused by Fusarium oxysporumSchlenhtend ex Fr f. sptulipae Apt. The first visible signs of infection on the bulbs are small, pale brown or grey sunken flecks on the outermost fleshy scales that become dark brown with age and enlarge in size. A satisfactory control is achieved by dipping bulbs for 2 hours in a 0.5% formalin solution.
Viral:
Tulip breaking Virus: This is the most commonly seen virus disease in tulips. It causes colour breaking or streaking of the flower colour in pink, purple and red-flowered tulips. The disease is spread by several aphid species (Myzuspersicae, Macrosiphum euphorbia andAplusfahar). Infected bulbs should be removed and destroyed. Planting of tulips near the lilies should be avoided.
INSECTS AND PESTS
Tulip Bulb Aphid: This aphid Dysaphistulipae also attacks iris, freesia, gladiolus and crocus. It is grey with a waxy appearance and clusters under bulb coats. Dipping of bulbs in diazinon is required to control.
PHYSIOLOGICAL DISORDER
Topple: It is called wet stem or water neck, when flower stem collapses and falls over late in the flower development or after the flowers picked are on the way to market. It is due to high temperature and localized calcium deficiency in the stem.
Blind flower: In case of blind flowers, though flower initiation occurs normally but it fails to complete development and aborts at some stage after initiation. The abortion of a flower may involve the flower alone or part of the flower.
HARVESTING
Flower: Tulip flowers are ready to harvest during February-April in the mid-hills, whereas in the high hills they flower from April-June. Flowers are harvested when the entire bud is coloured but still closed.
Bulb: Bulbs are harvested when leaves start turning yellow. It takes about 40 45 days after flowering. Bulbs must be lifted every year.
YIELD
The yield of flowers varies according to plant density, size of bulbs, cultural practices adopted and prevailing climatic conditions. If planted at a density of 50-60 bulbs/m², approximately 4-5 lakh cut flowers/ha can be obtained.
