Seed Technology and Planting Material
What this domain tests
Seed quality attributes, the seed certification chain, testing methods, seed treatment, seed-rate calculation, seed storage and the planting material used for vegetatively propagated crops.
Core rules
- Four quality pillars: genetic (trueness to type), physical (purity and freedom from inert matter and weed seed), physiological (germination and vigour) and sanitary (free from seed-borne pathogens and insects).
- Seed classes in sequence: nucleus → breeder → foundation → certified → truthfully labelled (TL). Certified seed carries a certification tag; TL seed is sold on the producer's own declaration of quality.
- Standard tests: germination in rolled towels or petri dishes, physical purity, moisture by oven or moisture meter, 1000-grain weight, and tetrazolium for viability of dormant seed.
- Seed treatment: thiram or carbendazim for seed-borne fungi, Rhizobium and phosphate-solubilising bacteria for legumes, imidacloprid for early sucking pests. Treat before sowing; never send treated seed to the kitchen.
- Seed rate depends on test weight, germination percentage, purity percentage and expected field establishment.
- Vegetative material: three-bud sugarcane setts, potato tubers, mango and citrus grafts and budlings, hardwood and softwood cuttings, rhizomes, suckers and tissue-culture plantlets.
Worked example
Target population 4,00,000 plants per hectare; test weight 25 g per 1000 grains; germination 90%; purity 98%; field establishment 90%. Reasoning: viable fraction = 0.90 × 0.98 × 0.90 = 0.794. Seeds to sow = 4,00,000 / 0.794 ≈ 5,03,900. Mass = 5,03,900 × 0.025 g ≈ 12,600 g, so about 12.6 kg/ha.
Traps
Giving a seed rate without test weight and germination; confusing foundation seed with certified seed; saving seed from a hybrid crop; and applying the germination percentage without allowing for field establishment losses.