गेहूं में गुणवत्ता बीज उत्पादन तकनीक
Wheat is the major stable food it is widely grown in the world, wheat grain contains carbohydrate (60-70%), protein (10-12%), fat (1.5-2.0%), minerals (1.8%)and other essential nutrients. It is an annual, long day and self-pollinated belong to the family Poaceae.
Quality characteristics which are important for flour protein concentration, rheological properties, bread-making and milling quality. In the world third position after rice and maize in production and cultivated area.
Land requirements:
land requirement for the seed production should be free from weed, volunteer plants and other diseases contamination. It should be well drained, soil neither alkaline nor acidic, wheat crop was not sown in the previous year.
Source of seed:
Production of foundation seed require breeder’s or foundation seed and for the certified require foundation seed which obtained from a source recognised by a certification agency. Seed bag attached with labels that verify class and purity of the seed and labels are retained after sowing.
Isolation distance:
Normally wheat is a self-pollinated crop but sometimes natural out crossing 1-4% occurs. So prevention from any contamination 3 meters’ isolation distance between two fields is sufficient. In case of loose smut diseases recommended about 180 meters for foundation seed and 150 meters for certified seed.
Land preparation:
Before sowing of the wheat seed bring the soil to a fine tilth by one deep ploughing with the turning plough followed by harrowing 2-3 times. Pre-sowing soil treated with quinalphos 1.5 % at the 20-25 kg per hectare during last ploughing for well mixing in the soil, controlling diseases and insect. In the finally prepared field pre-sowing irrigation should be given for maintain soil moisture which help in better germination of the seed.
Sowing time and Seed rate:
Sowing time for long duration varieties first fortnight of November and short and medium duration varieties should be sown second fortnight of November. The recommended seed required at timely sown 85-100 kg and for late sown varieties 100-120 kg seed.
Sowing method and spacing:
Different wheat varieties seed should be kept separately check out individual bags and tags for that variety, cleaned the seed drill before putting that particular variety seed. The seed sown in rows with seed drill, depth of the seed should be kept 4-5 cm and row to row distance maintain 20-22.5 cm to intercultural operations.
Fertilisation:
For better production recommended doses of fertilisers are 120 kg nitrogen, 60 kg phosphorus and 40 kg potash per hectare. Whole phosphorus, potash and half dose of nitrogen should be given just before sowing and half dose of nitrogen at first and second irrigations, fertilisers gives better responses through band placement. The fertiliser should be dropped 5 cm away from the seed and uniformly applied into the soil.
The recommendation of soil testing should be followed if zinc deficiency noticed then 20-25 kg zinc sulphate give at before sowing. Foliar spray of urea for proper grain development at the time of seed setting.
Irrigation:
Depending on the soil, in light soil more water require than the heavy soil but for seed production 6 irrigation must be required. In the light soil two-three extra irrigations required, if there is rains at the time of irrigation, then should not give any irrigation.
| Number | Stage of irrigation | Days after sowing |
| 1 | Crown root initiation stage | 20-25 |
| 2 | Tillering stage | 40-45 |
| 3 | Late jointing stage | 70-75 |
| 4 | Flowering stage | 90-95 |
| 5 | Milking stage | 110-115 |
| 6 | Dough stage | 120-125 |
Interculture operation:
Interculture means weeding and hoeing they are essential for better growth and healthy plants. Timely done about 30-35 days after sowing first weeding and other weeding required should be done. Pre-emergence of stomp @ 1 kg ai per ha for controlling the phalaris minor and after sowing spray of isoproturon @ 1 kg ai per ha in 750 litres of water. Broad-leaved weeds are control by spray of 2-4 D at the rate of 0.5 kg ai per ha in 750 litres water after 25-30 days of sowing.
Roguing:
Seed certification standard require 2-3 roguing first roguing at flowering, remove off type plants, plants susceptible to various diseases, tall and early heading plants, loose smutted plants inseparable other crops like barley, oat and other variety of wheat on the basis of their distinguished characteristics.
Second just after flowering the ear characteristics at this stage are apparent and off types removed and third roguing at maturity objectionable weed plants such as convolvulus arvensis and phalaris minor other crop plants oats, gram should be removed at this stage.
Plant protection:
At a global scale, about 10-28 percent yield losses in wheat by diseases and pests. Reduced the losses by seed treatment and after sowing with uses of fungicides, insecticides and cultures in appropriate doses.
| No. | Diseases and Insects | Diseases symptoms | Control measures |
| 1 | Yellow rust or stripe rust | Mostly this type rust occurs in Rajasthan its first appearance yellow to orange urediniospores on leaves, leaf sheath, awns and glumes. It starts with small patches and spread out large scale in the field. | Grow rust resistant varieties, use balanced and recommended doses of fertilisers special avoid high dose of nitrogen. Seed treatment before sowing with thirum @ 2-3 g/kg seed and in standing crop spray of propiconazole @ 0.1%. |
| 2 | Powdery mildew | Appearance of this diseases in small greyish patches of white cottony growth on both side of leaves, stem and ear head. White patches turn into brownish to dull tan colour. | Spray of triadimefon 25 % WP @ 0.1% at first appearance. |
| 3 | Loose smut | The smutted spike emerged from the boot leaf earlier than healthy plants, spore mass covered by a silvery membrane it raptures before ear emergence exposing dark, brown powdery mass in place of normal spikelets. | Destroy the infected tillers, seed treatment with carbendazim 50 WP @ 2.5g/kg seed. |
| 4 | Karnal bunt | It very difficult to diagnose infield because infected plants are not identifiable it normally noticed after threshing whole grain converted into the black powder of bunt spores. | Zero tillage reducing the incidence of karnal bunt, in the infected field spray of propiconazole @ 0.1% at flowering time. |
| 5 | Termites | Termites attack the crop at various growth stages, damaged plants can be easily uprooted and dried, plants show yellowing and drying plants observed in patches. | Seed treatment with chloropyriphos 20% EC @ 4ml/kg seed in the standing crop 20 EC chloropyriphos in 2 litres water and mix in 20 kg sand then broadcast evenly in 1 ha. |
| 6 | Stem borer | Larvae of this pest attack at tillering stage due to damage tillers die and at later stage due to damage causes white dead hearts. | Infected plants are destroying avoid excess use of nitrogen, in the standing crop spray of 25% quinalphos 800-1000ml in 500 litres of water per ha. |
| 7 | Mites | Mites causes loss of chlorophyll on the infested leaves minutes’ yellowish spots plants are stunted | Spray of propargite 57 SC @ 1.5 ml/l of water per ha. |
Harvesting and Threshing:
After maturity crop should be harvested and avoid shattering and sprouting the ear due to delay in harvesting. At the time of harvesting moisture should not more than 15% it done with sickle or combiner. Combine the harvested bundles and threshing with thresher or combiner before utilization equipment should be clean ensured that not even a single grain of the previous variety and other crop seeds.
Processing:
After harvesting and threshing seed should be dried and cleaned using natural (sunlight and air) and artificial (bin driers and wagon driers) methods. The seed bags should be cleaned and threshed by dipping in 1% malathion solution for 10 minutes or fumigating them with ED/CT mixture @ 1 litre per 10 bags or dipping them in hot water for 15 minutes.
The bagged seed should be stored in dry and cool store room where proper sanitation and insulation. In the store room bags should be stacked on wooden pallets. During storage protect from insects and rodent for control of insects, fumigation of store room with any fumigants or neem seed powder 100:1 ratio for prevention from rodent using traps and poison baiting such as zinc phosphide and warfarin etc.
Seed yield:
All above the process followed properly average seed yield should be 30-40 qtls per hectare.
Purity standard of seed:
A farmer depends on the quality seed because seed is the basic inputs in agriculture. The quality of seed generally determined by their different tests like germination, purity, moisture and seed health, it can be evaluated by central and state testing laboratories. In India each state has at least one seed testing laboratory to conduct the quality/standard of seed.
| Field standard for quality seed production | |||||||||||
| Field inspection | Stage at made inspection | Isolation distance for foundation seed (m) | Isolation distance for certified seed (m) | Maximum off-type (%) permitted | Maximum inseparable Other crop seed (%) |
Seed born disease infected plant (%) | |||||
| C | D | C | D | F | C | F | C | F | C | ||
| 2 | Flowering to harvest | 3 | 150 | 3 | 150 | 0.05 | 0.3 | 0.01 | 0.05 | 0.1 | 0.5 |
Where: C=Crop, D= Diseases, F= Foundation, C=Certified
| Seed standard for quality seed production | ||
| Parameters | Foundation seed | Certified seed |
| Pure seed (minimum %) | 98 | 98 |
| Inert material (maximum %) | 2 | 2 |
| Other crop seed (maximum per kg) | 10 | 20 |
| Total weed seed (maximum per kg) | 10 | 20 |
| Other distinguishable varieties (maximum per kg) | 10 | 20 |
| Objectionable weed seed (maximum per kg) | 2 | 5 |
| Germination (minimum %) | 85 | 85 |
| Moisture (maximum %) | 12 | 12 |
(Agril. Ministry, Govt. of India, Seed Certification Standard, 1971)
Refrence: Sen and Ghosh 2010, Seed Science and Technology second edition.
Author:
Madhu Choudhary
Division of Plant Breeding and Genetics
Rajasthan Agricultural Research Institute, (SKNAU), Durgapura-302018, Jaipur
Author’s E-mail: