Quality Seed Production Techniques

Seed and Seed Quality

Seed is a fertilized mature ovule that posses an embryonic plant, stored food material (endosperm) and a protective coat (testa), which is viable and has capacity to germinate. Seed materials includes all vegetatively propagated materials like tubers of potato, bulb of onion and garlic, rhizome of turmeric, zinger, roots of yam, cassava, sets of sugarcane, cuttings of flowers and fruits. Quality seed is defined as varietelly pure with a high germination percentage, free from disease and disease organisms, and with a proper moisture content and weight. Quality seed insures good germination, rapid emergence, and vigorous growth. These aspects translate to a good stand (whether greenhouse or field). Seed is said to be of quality if it is scientifically produced and is distinctly superior in term of physical, genetic, physiological and pathological parameters.

Characteristics of Quality Seed

Seed quality describes the potential performance of a seed lot. Trueness to variety; the presence of inert matter, seed of other crops, or weed seed; germination percentage; vigor; appearance; and freedom from disease are important aspects of seed quality. As the delivery mechanism for new plant technologies and varieties, seed is also the crux of agriculture. Quality seed is essential for growing quality crops. Products grown from seeds are critical in meeting modern consumers’ needs for the “Four F’s” – food, feed, fiber, and fuel.

A quality seed should fill following quality criteria: Physical quality Genetic quality, physiological quality, pathological and entomological quality.

A. Physical quality

• Seed should be clean and free from impurities
• Free from inert materials like stones, mud, husks, broken seed
• Free from weed seed (objectionable and noxious)
• Free from other crop seed
• Free from other variety seed

B. Genetic quality

• The variety of seed should be true to the type (same as parent material)
• There shouldn’t be any genetic deterioration in the variety

C. Physiological quality seed

• Seed should be bold and plump
• High germination percentage
• Viable and high vigor

D. Pathological and entomological quality

• Seed should be healthy
• Free from seed borne diseases: disease spores in or on the seed
• Free from egg, larvae, adult of insect
• Treated with chemicals like vitavex, thiram

Importance of Quality Seed

• Quality seed is basic input in crop production
• It has high genetic potential
• It is a carrier of new technology: Green Revolution
• It gives high quality produce: fetches high market price
• It reduces the amount of seed requirement: by about 25%
• Less chances of weed, insects and diseases: decrease cost of production
• It improves productivity of crops: by about 25%
• It helps in food self-sufficiency and security in the country.

Production Techniques of Quality Seeds

1. Selection of Soil:

For successful seed production, soil should be preferably loam. Other soils like sandy loam to clay are also good. The soil should be well fertile and free from water stagnation and have 6.5 to 7.5. Since most the crops have tendency to shatter the seeds in the field and hence, the same crop may not be selected to grow year after year to avoid contamination.

2. Raising of Seedlings:

Generally seeds of annuals are sown in controlled space for better handling owing to small size of seeds. In general, 10-15 cm raised nursery seeds of 1 m width and 2-3 m long are prepared. The soil should be well prepared by mixing 10-15 kg/m2 well rotten farm yard manure. To check the soil borne diseases in nursery, soil should be drenched with 0.2% brassicol or captan or soil can be sterilized by drench with 2% formaline and covering with polythene.

3. Direct Sowing of Seeds:

Many flowers are sown directly. For this 15-20 cm wide ridges are prepared by manual or tractors. Three to 4 seeds are sown directly by hand at 15-20 cm apart. After complete sowing light watering is done. Seeds start germinating after 4-5 days.

4. Preparation of Land and Transplanting of Seedlings:

Before laying out the field, the land should be well prepared by ploughing by harrowing and mixing 15-20 tonnes well rotten farm yard manure/acre. It has been observed that instead of flat planting raised bed method of planting is more useful. Therefore, raised beds with tractor are prepared and keeping the spread of plant seeds longs are transplanted on both sides of raised bed or in center.

5. Isolation Requirement:

Generally no isolation distance is required for strictly self-pollinated crops, whereas a distance of 25 m is beneficial. For often cross pollinated and cross pollinated crops the isolation distance of 100 and 1000 m is kept, respectively. Seed producing companies those are busy in custom seed production, select the farmers in different villages and are given a programme of seed production of one line of single type. This helps in better isolation.

6. Management of Annuals:

Annuals are quite tender and require proper attention through-out their life. Regular water supply is essential for successful raising which should be done according to the requirement of the crop. Sufficient moisture is required till harvesting of seed is done. Depending upon season and soil type frequency of irrigation is decided. In rainy season generally irrigation is not required except during dry spell. During winter season, irrigation is required at 10-12 days where during summer season it should be done at 4-5 days. Regular weeding and hoeing is essential for the development of seedling in to healthy plants.

7. Rogueing:

Seed producer should have a detective eye to observe off type or improved type in the field. He should keep constant vigil from the beginning of the crop to the maturity. It is utmost important to remove and destroy the off types whereas if any plant exhibits superior trait in terms of vigour earliness, colour, or size of flower, etc., the seed of such plant should be preserved for further testing and utilization.

8. Insects, Pests and Diseases:

The annuals are commonly attacked by Heliothis sp., aphids, leaf miner etc. Protective control measure should be taken well in advance to avoid any considerable loss. The heliothis sp. attacks mostly Antirrhinum coreopsis, carnation, dianthus, etc. and it can be controlled by spraying of 0.1% chloropyrophos at an early stage of caterpillar. Aphids commonly attack alyssum, stock, nemasia, calendula etc. Spraying of 30 EC Rogor or 25 EC metasystox @ 250 ml/200 L/acre is effective to control it.

Different fungi attack many annuals at different stages such as in nursery or in the field. Seed dressing with Bavistan (1 g/kg) or captan (3 g/kg) or drenching with the infected nursery beds with 0.2% Brassicol or Bavistan (0.1%) is quite effective. The seed virus cannot be controlled by using chemicals and effective control is destroying of the plants or by controlling the vectors by using effective insecticides.

9. Harvesting and Storage of Seeds:

The seeds are cleaned and sieved with different types of seed machine and seeds are finally cleaned by hand winnowing or using table fan to separate light seeds. In certain machines brushes are attached to remove the hairs or appendages. The seeds after proper cleaning are packed in muslin bags H.D.P.E. bags with silica gel and are stored in cool and well ventilated room.

Writer: Sandesh Paudel