Introduction to Tomato Seed Production
- Tomato (Solanum lycopersicum) is a major solanaceous vegetable crop.
- Native to the Peruvian-Mexican region; introduced to India by Portuguese travelers.
- Valued for its nutritional content, including vitamins C, A, and B.
- Widely cultivated for fresh consumption and processing industries.
Botanical Description and Plant Characteristics
- Scientific name: Solanum lycopersicum
- Family: Solanaceae
- Chromosome number: 2n=24
- Annual, terrestrial plant with compound, alternately arranged leaves.
- Inflorescence is a cyme; flowers are yellow, perfect, and hypogynous.
- Fruit is a fleshy berry with 2–9 locules, usually red, orange, or yellow when ripe.
Importance and Uses of Tomato
- Consumed as a vegetable and in processed forms (soup, ketchup, sauce, paste, juice).
- Rich in minerals: potassium, calcium, magnesium, phosphorus, boron.
- Medicinal uses: promotes gastric secretion, acts as blood purifier, intestinal antiseptic.
- Tomato seed oil is used in salad dressings and margarine production.
Major Tomato Varieties in India
- IARI, New Delhi: Pusa Early Dwarf, Pusa Ruby, Pusa Red Plum
- IIHR, Bangalore: Arka Saurabh, Arka Vikas, Arka Alok, Arka Vishal
- PAU, Ludhiana: Punjab Tropic, S-12, Punjab NR-7
- Private sector: Mangala, Sheetal, Vaishali, Rupali, Rashmi, Naveen
Floral Biology of Tomato
- Inflorescence: Cymes, flowers borne in clusters.
- Anthesis: Begins at 6 a.m., peaks 7–8 a.m.; anther dehiscence peaks 9–11 a.m.
- Stigma receptive 16 hours before anthesis, remains receptive 2–3 days after.
- Optimum pollination temperature: ~21°C; pollen viability: 7–10 days at 20°C, 70% RH.
Climate and Soil Requirements
- Warm-season crop; optimal temperature: 20–28°C.
- Cannot tolerate frost; temperatures below 15°C or above 39°C affect fruit set.
- Prefers well-drained, fertile, organic-rich soils with pH 6–7.
- Moderately tolerant to acidic soils (pH as low as 5.5); lime recommended for low pH.
Propagation and Nursery Management
- Propagated by seeds; nursery beds should be porous and fertile.
- Seeds sown in lines 5 cm apart, covered with sand, and watered gently.
- Dry grass cover for 3–5 days promotes early germination.
- Seedlings ready for transplanting at 25–30 days, 10–15 cm tall.
Seed Rate and Seed Treatment
- Seed rate: 500–800 g/ha; ~300 seeds per gram.
- Seed treatment with IAA in talc powder enhances germination and vigor.
- Seeds may be treated with fungicides (e.g., captan or thiram) before sowing.
Nutrient Management
- Tomato is a heavy feeder of N, P, and K.
- Irrigated: 250:250:250 kg NPK/ha; Rainfed: 60:50:30 kg NPK/ha.
- Apply 35 t/ha FYM before planting.
- Micronutrients (Ca, B, Zn) applied via foliar sprays.
Fertilizer Application Methods
- Organic manures incorporated before final ploughing.
- N applied in 2–3 splits: after transplanting, at flowering, and at fruiting.
- Full P and K applied at planting, mixed into soil near rows.
Transplanting and Spacing
- Seedlings transplanted at 3–4 weeks, 10–15 cm tall.
- Spacing: 60 × 30 cm; ridges preferred in heavy soils.
- Transplant in the evening; irrigate immediately after planting.
Irrigation, Interculture, and Weed Management
- First irrigation after transplanting, second on day 3, then at 7-day intervals.
- Weekly irrigation in hot season; irrigate during frost risk in winter.
- First weeding at 25 days, earthing up at 45 days after planting.
- Pre-plant herbicide application can aid weed control.
Pest and Disease Management
Major Insect Pests:
- Fruit borer, jassids, tobacco caterpillar, whitefly, root-knot nematodes.
- Control: Hand picking, crop rotation, insecticides, resistant varieties.
Major Diseases:
- Damping off, buckeye rot, Fusarium wilt, early blight, late blight, bacterial canker, leaf curl virus.
Physiological Disorders:
- Blossom end rot, cat face, fruit cracking.
Training, Pruning, and Roguing
- Plants supported with stakes to prevent lodging and fruit-soil contact.
- Roguing removes off-types and diseased plants at pre-flowering, flowering, and fruiting stages.
- Ensures genetic purity and seed quality.
Harvesting and Seed Yield
- Fruits harvested at pink to red ripe stage for seed extraction.
- Hybrid seed yield: 40–50 kg/ha under optimal conditions.
Seed Extraction Methods
Fermentation Method:
- Crushed ripe fruits fermented until pulp separates from seeds.
- Seeds washed and sun-dried.
Alkali Treatment:
- Pulp treated with alkali, left overnight; seeds settle and are washed.
Acid Treatment:
- Pulp mixed with 5–6 ml/kg HCl, stirred, washed after 30 min, seeds dried.
Seed Washing, Drying, and Grading
- Seeds washed thoroughly to remove pulp and mucilage.
- Dried rapidly to 8% moisture on trays or cloth in sun.
- Graded using sieves (0.6–0.8 mm); larger seeds preferred for quality.
Seed Packing and Storage
- Seeds treated with captan or thiram (2 g/kg seed) before storage.
- Packed in moisture-proof containers at 8–10% moisture content.
- Viability maintained for 25–30 months under proper storage.
F1 Hybrid Seed Production in Tomato
- Requires separate male and female parent lines (ratio 1:5).
- Emasculation of female flowers at late bud stage; anthers removed.
- Pollen from male parent applied to stigma of emasculated flowers.
- Bagging prevents unwanted cross-pollination; tagged for identification.
Field and Seed Standards for Tomato
Field Standards:
| Factor | Foundation Seed | Certified Seed |
|---|
| Isolation Distance | 50 m | 25 m |
| Off-types (max %) | 0.1 | 0.2 |
| Other Crop Plants | None | None |
| Diseased Plants (max %) | 0.1 | 0.5 |
Seed Standards:
| Standard | Foundation Seed | Certified Seed |
|---|
| Pure Seed (min %) | 98 | 98 |
| Inert Matter (max %) | 2 | 2 |
| Other Crop Seeds (max/kg) | 5 | 10 |
| Weed Seeds | None | None |
| Germination (min %) | 70 | 70 |
| Moisture (max %) | 8 | 8 |
| Moisture (vapour-proof, max %) | 6 | 6 |