Onion seed production


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Onion seed production

  1. 1. 1
  2. 2. INTRODUCTION Onion (Allium cepa L.) is a major bulbous crop among the cultivated vegetable crops and it is of global importance. Top 3rd vegetable with production of 1.064 mT 15.118mha. India needs around 7000 tonns of seeds annually.
  3. 3. Anthesis occurs in early morning (6-7 hrs). Anther dehiscence is between 7.00 and 17.00 hr and on next day also with peak between 9.30 and 17.00 hr. Pollen fertility is highest on the days of anthesis. Stigma receptivity is also high on the day of anthesis (Jones, 1933). The duration of anthesis is approximately 4 weeks on individual umbel. . FLORAL BIOLOGY
  4. 4. FLORAL BIOLOGY The anthesis begins from outer flowers and goes centrally in succession The flower is protandrous in nature and stigma becomes receptive when shedding of pollen is over.
  5. 5. Onion is cross- pollinated in nature and bees, flies and other insects do pollination. It is essential to ensure that there is sufficient population of pollinating insects to achieve the full potential of onion seed. It is also possible in some situation to encourage the development of increased blowfly population by distributing suitable carrier or dried fish among the flowering crop (Currah and Proctor, 1990). POLLINATION
  6. 6. LAND REQUIREMENT Land to be used for seed production of onion should be free from volunteer plants. Although onion can be grown nearly in all types of soil from sandy loam to loam. heavy clay soil should be avoided, but unless they are satisfactory well supplied with humus to lighten them. The soils pH should preferably be 6.0-6.8.
  7. 7. CLIMATE & SEASON It is being a short day favored crop it is advised to grow during rabi season for seed production. Desai et al reported that temperature around 21.1°c favours vegetative growth, where as lower temperature around 12.8°c are continue to seed stalk formation and shortday condition also favours to seed production.
  8. 8. METHODS OF SEED PRODUCTION There are two methods of seed production. Seed to seed method Bulbs to seed method Both the methods are in use in onion seed production. But bulb to seed method is most commonly used method of seed production.
  9. 9. SEED TO SEED METHOD In this method seedlings are transplanted in first week of October and allow over-wintering at the same place and allowing bolting (flowering). The seed are threshed from the mature umbel. This method does not allow to examine the mature bulb characters and field is rogued for off-types. Seed to seed method is not popular, since all the variety are not suitable for annual seed production due to poor bolting habit and lower seed yield.
  10. 10. SEED TO SEED METHOD CONTINUED… The seed produced in this method is not suitable for further multiplication. The seeds produced from this method having low genetic purity, But advantage here is low cost of seed production compared to bulb to seed method.
  11. 11. BULB TO SEED METHOD Here in first season bulbs are produced, which after maturity are harvested and bulbs which are true to type are sorted and stored. The rabi and late kharif varities are stored for next season and kharif varities are given rest for 15-30 days. The stored bulbs are planted in the next season to produce seeds. Top 1/3 portion of the bulb is cut to examine the number of axis of growing center preferably single centered and medium to large sized bulbs should be chosen and soaked in Ig/litre bavistin & corbosulphon 1m/litre.
  12. 12. This method is widely practised it allows us to examine the bulb characteristics and rouging of undesirable bulbs hence genetic purity is high in this method of seed production One hectare of bulbs from the first year will plant 3-5 ha for the seed production. The bulbs selected for seed production and usually referred to as mothers bulbs. 4-6 cm size bulbs are selected for getting good crop (Pandey 1996). BULB TO SEED METHOD CONTINUE…
  13. 13. FERTILIZERS FYM @ 25 tons/ha, NPK @ 100:50:50 kg/ha apply 50:50:50 kg/ha NPK at the time of planting & remaining nitrogen in 2 splits, one at 30 days and 2nd at 45-60 days after planting. Give 1% spray of Poly feed (19:19:19, NPK) at 30 & 60 days after planting & one spray of multi K (0:0:50) after 60 days of planting.
  14. 14. ISOLATION For mother bulb production 5 m isolation should be maintained. Since onion is cross pollinated through insect (entomophilous) two varieties have to be well isolated from each other. An isolation distance of 1000 m for foundation seed and 500 m for certified seed shall be provided all round a seedfield to separate it from fields of other varieties, fields of the same variety not confirming to varietal purity requirement for certification.
  15. 15. SOWING SEASON The seeds are sown in may-June for harvesting of bulbs in October- November. Selected bulbs are planted in November-December to produce seed in April-may for use in the next season. Oct.-Nov. planting is the best time for tropical types. Dharm Singh and Ranjeet Singh (1991)stated that the best time for bulb planting is 3rd week of October. Malik et al. (1999) reported that highest yield and quality of seed was recorded for 15th October planting. Bulbs must be stored in well-ventilated storage structure with temperature 25-30°C and RH 65- 71%.
  16. 16. SEED RATE & SOWING Spacing: 15 x 10 cm bulb production. 45 x 30 cm, 60 x 20 cm (on drip) Bulb Rate Total of 25-30 quintal bulbs are needed for one ha. depending on the size of the bulb (Pandey, et al.) Weed Management: Spray Goal @ 1.5 mI/L after planting of bulbs and one weeding after 45 to 60 day after planting should be done. Weedicides like pendimethalin at 2.5-3.5 litlha or oxyflorofen at 0.15-0.25 liters ha with one hand weeding at 45 days given good control of weeds.
  17. 17. IRRIGATION AND AFTERCARE • Irrigation is given at 7-10 days interval depending on types of soil and season. • Earthing is done 2 months after transplanting to avoid lodging. Weeding and hoeing are done as per requirement.
  18. 18. FIELD INSPECTION A. Mother bulb production stage • First inspection shall be made after transplanting of seedlings in order to determine isolation, volunteer plants, off-types including bolters and other relevant factors. • The second inspection shall be made after the bulbs have been lifted to verify the true characteristics of bulbs.
  19. 19. FIELD INSPECTION B. Seed production stage • The first inspection should be made before flowering in order to determine isolation, off types including bolters and relevant factors. • The second and third inspection shall be made during flowering to check isolation, off types and other relevant factors. • The forth inspection shall be made at maturity to verify the true nature of the plant and other relevant factors.
  20. 20. ROGUEING Plot should be visited regularly. Yellow and lanky plants should be removed before flowering. Plants with differential umbel height should be removed before opening of flowers. Plants affected by aster yellow and stemphyllium blight should be removed before seed harvest.
  21. 21. MEASURE TO IMPROVE POLLINATION Following points should be taken care of for improving the pollination. • Bee colonies should be kept in field . • Irrigation should be given more frequently at the time of flowering and seed setting. • Only safer insecticides should be sprayed during flowering. • In case of high wind, sometimes bees do not sit on the flowers. To avoid this plant wind breakers all round the field.
  22. 22. MATURITY, HARVESTING AND CURING All seed heads do not mature simultaneously, therefore, harvesting is done in installments. When seed inside capsules become black and 20-25% black seeds are exposed the umbels should be cut with 10-15 cm stem attached. The umbels are spread on ground or canvas to avoid attack of mould for drying. When seed inside capsules become black and 20 - 25% black seeds are exposed, the umbels are cut with 10 – 15 cm of stems attached. • The optimum moisture content is 10 to 15 per cent at the time of harvesting (Khurana and Mehra, 1986; Brewster 1994)·. • The heads are spread on ground or canvas to avoid attack of mould and obtain uniform drying.
  23. 23. PESTS AND DISEASES Pests: Thrips Disease: Purple blotch White rot Stemphylium blight
  24. 24. POST HARVEST MANAGEMENT Cleaning • Onion seed can be cleaned using any regular screening and fanning mill, after which it is separated by employing gravity separators. • For safe storage, seeds are dried to a level of about 6% moisture and then packed in aluminium foils or tins. • Then it is stored in air conditioned and dehumidified store having a temperature of 20-25ºC and relative humidity of 30-40%. • In hot and humid climate, viability of onion seed is lost within an year. • Onion seed if dried to 6.0% moisture level and stored in sealed containers, its life may be prolonged to 3-4 years without evident loss in seed germination.
  25. 25. Seed yield: 500 - 800 kg seed/ha, in best management and climatic conditions 1000 to 1200 kg seed can be obtained. Grading Seeds are size graded using BSS10 X10 wire mesh sieve and the seeds retained by this sieve alone is recommended for sowing/storage.
  26. 26. CERTIFICATION STANDARDS-FIELD STANDARDS Contaminant Isolation distance (m) Mother bulbs production Seed production Foundation Seed Certified Seed Foundation Seed Certified Seed (A) General requirements Field of other variety 5 5 1000 500 Field of the same variety notconforming to varietal purity requirement for certification 5 5 1000 500 (B) Specific requirements Bulbs not confirming to the varietal characteristics 0.10% (by number) 0.20% ( by number **Off-types 0.10% 0.20%
  27. 27. SEED STANDARDS Factor Maximum permitted limit Foundation Seed Certified Seed Pure seed (min) 98.0% 98.0% Genetic purity (min) 98.0% 98.0% Insert matter (max) 2.0% 2.0% Other crop seed (max) 5.0/kg 10.0/kg Weed seeds (max) 5.0/kg 10.0/kg Germination (min) 70.0/kg 70.0/kg Moisture (max) 8.0% 8.0% For vapour-proof containers (max) 6.0% 6.0%
  29. 29. HYBRID SEED PRODUCTION I.Hand emasculation and pollination : Flowers are very small, androgynous, very few seeds/ cross. It is time and labour combursum, so, it is not economical. Not followed also. II. Use of Male sterile lines-4F:1M a) CMS :commonly used b) CGMS : also used but high cost of production.
  30. 30. USE OF MALE STERILE LINES In onion the use of male-sterile lines is common to produce seeds of F1 hybrids. The male sterility in onion is due to the interaction of cytoplasm and nuclear gene The nuclear gene is single recessive msms while its dominant allele MsMs is for male fertility.
  31. 31. PARENTAL LINES Three parental lines, namely A, B and C, are used for hybrid seed production. The line A, known as the female parent, is male sterile having the genetic constitution Smsms, which produces hybrid seeds, The line B with the geno-type Nmsms is the male-fertile counterpart for the maintenance of male sterility of line A The line C is the fertile pollen parent or inbred which is genetically diverse from the lines A and B.
  32. 32. PROCEDURE The hybrid seed is produced in the open in an isolated field. The bulbs of A (male sterile) and C (pollen parent) lines are planted alternately in a ratio of 4 rows of the A line to 1 row of the C line. Sometimes 8 rows of the A line are alternated with 2 rows of the C line. The flowering in the lines A and C must synchronize. If it does not, it can be accomplished by adjusting planting dates of the lines A and C. Daily rogueing of pollen-bearing plants and other off-types in the line A in the morning before the anthers dehisce is essential. When the seed of the line C is not to be saved its flower stalks may be cut and destroyed as soon as the pollination is completed.
  33. 33. Thank you