This article throws light upon the top nine seed production techniques. The techniques are: 1. Selection of Soil 2. Raising of Seedlings 3. Direct Sowing of Seeds 4. Preparation of Land and Transplanting of Seedlings 5. Isolation Requirement 6. Management of Annuals 7. Rogueing 8. Insects, Pests and Diseases 9. Harvesting and Storage of Seeds.
Technique # 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.
Technique # 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.
For better handling of small seeds, these are mixed with bulk material like sand or ash. Seeds are sown by hand in line 5-6 cm apart and .5 cm deep. The depth can be increased with the increase in size of seed. A seed sowing machine has been developed by Beauscape Farms, Sangrur. The seeds sown from this machine are sown at uniform depth and distance.
After sowing seeds are covered with well sieved mixture of farm yard manure and soil. Watering should be done twice or thrice a day or use sprinkler system. The seeds are covered with newspapers or bed sheet to create darkness which helps in better germination. The seeds start germinating within 2-3 days and covering is removed.
It takes about one month to grow the seedling sufficiently and is ready for transplanting when seedlings have 3-4 true leaves. For raising one acre nursery 8-10 beds of 5 × 1 m are required. The quantity of seed for raising in nursery will depend upon size and weight of seeds.
Following amongst of seed is required for raising seedlings for keeping 3 seeds required for raising one seedling: Marigold (African)—400-500 g, Petunia—200 g; Island Poppy—150 g; Oenothera—200 g; Nemophylla—500 g; Eschscholtzia californica—200 g; Bellis perernnis—100 g.
Technique # 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.
Technique # 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.
In general 50 kg urea, 250 kg of single super phosphate and 60 kg of muriate of potash should be well incorporated in the soil. The application of remaining 100 kg urea should be applied in to two equal splits i.e. one and two months of transplanting of seedlings. It is advised that before transplanting light irrigation should be applied which helps in better establishment of seedlings.
The distance for tall annuals like helichrysum; delphinium; gaillardia is kept 60 × 45 cm, whereas for medium annual, (petunia, verbena, phlox, eschscholtzia, etc.) 45 × 45 cm and for dwarf annuals (pansy, mesembryanthemum, alyssum, daisy) 25 × 25 cm is kept, The seedling should be transplanted in cool hours of evening and should be watered lightly immediately.
Technique # 5. Isolation Requirement:
To produce genetically pure seeds, crop should be isolated with other varieties of same crop. (Table 13.2)
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.
Technique # 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.
Technique # 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.
Technique # 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.
Technique # 9. Harvesting and Storage of Seeds:
After vegetative phase, flowering occurs in succession which may last 30-60 days or even more resulting in maturity of individual flowers in succession. Therefore pods are harvested individually before the splitting occurs.
Whereas in many cases to save labour single harvesting with sickle is done at the cost of seed yield e.g. nasturtium, mesembryanthemum, Coreopsis tinctoria, Verbena tennusecta Phlox, Oenonenthra, Clarkia, etc. The seeds of Nasturtium are very bold and thus it is collected by booming the field.
Similarly the seeds of Chrysanthemum paludosum are collected by shaking the plant over sheet of cloth. The harvested seeds are spread over the tarpauline under shade or in ventilated room for week but reshuffled daily. In many cases seed along flower stock is plucked which provides moisture and nutrient to maturing seed e.g. daisy. Many big seed producers use green netlon 12′ high to provide shade for drying the 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.