Cultivation of TUBEROSE (Polianthes tuberosa)

Botanical Characteristics:

• Scientific Name: Polianthes tuberosa L.
• Common Name: Tuberose, Rajnigandha, Gule Shabbo
• Family: Amaryllidaceae
• Chromosome Number: 2n = 30 (diploid)
• Plant Type: Herbaceous perennial
• Origin: Native to Mexico
• Importance: Tuberose is a popular fragrant flower cultivated under open conditions for loose flowers and cut flowers.

Morphology:

• Bulbs: Underground, tunicated, rounded, ~2–5 cm in diameter
• Leaves: Long, linear, grass-like, basal, green
• Inflorescence: Spike, terminal, erect
• Flowers:
  • Waxy, white (sometimes tinged)
  • Intensely fragrant
  • Mostly night-blooming
  • Sessile, bisexual, tubular
• Flower Structure: 6 lobed perianth, superior ovary

Important Varieties and Types:

Single Type: Single Mexican: 2–3 rows of petals, preferred for loose flowers and essential oil extraction

Double Type: Suvasini, Pearl Double, Vaibhav, Kalyani Double, Hyderabad Double. >3 rows of petals, mostly for cut flower purpose

Variegated Type: Rajat Rekha (silver-striped leaves), Swarna Rekha (gold-striped leaves) Used as ornamental plants for gardens

Climate and Seasonality:

• Photoperiod: Day-neutral plant
• Ideal Temperature: 26–30°C
• Not frost-tolerant
• High humidity promotes vegetative growth and spike elongation
• Season for Maximum Yield: July–August planting results in maximum flower yield

Soil Requirements:

• Texture: Loamy, sandy loam
• Drainage: Excellent drainage is essential (avoids bulb rotting)
• pH Range: 6.5–7.5
• Avoid: Heavy clay soils, waterlogging conditions

• Season: Can be grown throughout the year. Best yield from July-planted crop
• Spacing: Between rows: 30–20 cm, Between plants: 20–10 cm

Propagation Methods:

• Main Method: By bulbs
• Bulb Size: 2–3 cm diameter for propagation
• Resting Period: 6–8 weeks; overcome with:
  • Thiourea 4% dip
  • Cold storage (10°C for 30 days)
• Alternative propagation: Micropropagation (in vitro culture using shoot tips or meristem)

Planting and Flowering Schedule:

Yield Potential:

• Bulbs mature after flowering ceases and leaves turn yellow and dry
• Harvest 40 quintals of bulbs/acre
• Bulbs mature 40–50 days after flowering

• Loose Flowers (Single type): 20–25 quintals/acre
• Spikes (Double type): 1.0–1.2 lakhs/acre
• Ratooning: Up to 3–4 ratoon crops from a single planting

Essential Oil Extraction:

• Uses: High-value essential oil for perfumes and cosmetics
• Extraction Method: Enfleurage or solvent extraction (not steam distillation as it’s heat-sensitive)
• Oil Content: 0.08–0.11% in fresh flowers
• Active Compounds: Geraniol, eugenol, nerol, benzyl alcohol

 Post-Harvest Handling:

• Storage of Cut Spikes: Place in cold water, Store at 10°C for up to 5 days
• Packaging:
  • Loose flowers: Bamboo baskets with cloth
  • Spikes: Graded, bundled (50–100), wrapped in newspaper
• Grading Criteria: Spike length, rachis length, flower size and quality

Crop Management:

Manuring and Fertilization:

• FYM: 20–25 t/ha before planting
• NPK Dose (kg/ha): 200:150:150 (split in 3 doses)
• Micronutrients: Zn and B improve flower quality

Irrigation: At weekly intervals during dry period, Avoid over-irrigation

Weed Control: Manual weeding or pre-emergence application of pendimethalin @ 1.0 kg/ha

Ratooning:

• After harvesting, flower stalks are cut to the base
• Plots are manured and irrigated
• 3–4 ratoon crops can be obtained from one planting

Storage of Flowers:

• Storage temperature: 10°C
• Duration: Up to 5 days

 Plant Protection:

Pests:

• Thrips:
  • Affects leaves, flower stalks, and flowers
  • Suck sap from plant parts
  • Control:
    • Spray endosulfan twice at 10-day intervals
    • Or spray dimethoate @ 2 ml/litre

Diseases:

• Stem Rot / Basal Rot (Sclerotium rolfsii):
  • Soil-borne
  • Symptoms: Coarse mycelial masses at or near the soil level on leaves
  • Control: Burn infected plants immediately

• Flower and Bud Rot / Flower Blight (Botrytis elliptica):
  • Bacterial disease
  • Symptoms:
    • Dry rotting of young flower buds
    • Brown, scorched, necrotic discoloration of peduncles
    • Shriveling and drying of buds
  • Control:
    • Burn infected plant debris

Spray carbendazim @ 1 gm/litre

Economic Importance:

• Used in:
  • Perfume industry (highly valuable oil)
  • Religious functions, garlands
  • Cut flower trade (domestic and international markets)
  • Landscape and ornamental horticulture

Recent Trends:

• Use of tissue culture for mass propagation
• Application of growth regulators like GA₃ to increase spike length
• Export potential in Middle East, USA, and European markets