In the current situation, herbal remedies have enlarged universal reputation by mutually the rapeutic and commercial consequences. Allium cepa, commonly known as Onion and locally as Piyaz, Ghanda in Pakistan is an important medicinal plant whose various parts are used to cure different health problems.
Onion Scientific Classification:
Species: Allium cepa
Production Technology: Onions can be propagated from sets or by sowing seeds. Seeds are sown in holes which are about 2cm deep in soil and with 1 inch among the seeds. Spaces between the lines (rows) are about 30cm away from each other.
Soil type for cultivation of Onion: Onions are cultivated mostly in every soil from heavy clay to sandy loams. Slightly acidic ground whose pH ranges from 5.5 to 6.5 is a better pH for the cultivation of Onions.
Cultivation: Allium cepa has been grown for 5000 years or more. Onion is a cool season crop. It is cultivated throughout winter and harvested before the real hot season begins. Onion can be cultivated under a wide range of seasonal conditions. But it succeeds best in mild season/conditions without excesses of cold and heat.
Manuring or Fertilizing: To get good yield, healthy and disease free cropit is very necessary to apply essential manures/composts or commercial fertilizers on crop at proper times.Well rotten farmyardfertilizer at 10 tons per acre applied when itploughed down at least one month earlier soil preparation. Before propagating seeds or sets following manures may applied:
3 bags (Ca (H2PO4)2) super phosphate fertilizer.
1 bag ((NH4)2SO4) ammonium sulphate fertilizer which contain nitrogen and sulfur.
1 bag (K2SO4) potassium sulphate fertilizer per acre.
1 bag ((NH4)2SO4) ammonium sulphate per acre one month afterward planting seeds/sets.
1 bag ((NH4)2SO4) ammonium sulphate may be applied on the crop when the time bulb formation takes place.
Crop Irrigation: Crop first watered instantly after transplanting sets or sowing seeds and later watering must be given at 7 to 10 days interval, Irrigation should be stopped before neck fall of Onion plants.
Harvesting and curing: When 50% crop displaying neck fall then the onions picked up out of the soil, it is required3 to 4 days of dry and warm conditions of weather for field curing.
Diseases of Onion and its control
Downy mildew: It is a fungal disease. In moist climate, mildew grows as purplish or white powder above the surfaces of leaves or in dry conditions of weather, simply white spots is seenon the plant parts. It is controlled by “Dithane M-45” or by different copper (Cu) based fungicides.
Purple blotch: It is serious fungal disease of onions. This disease attacks when the range of temperature is 25 to 30 °C and relative humidity is70 to 90% in the air. In this disease flower stalks and leaves show white spots with purple color in center. It is controlled to spray/shower the crop with “Dithane M-45” at weekly interval earlier appearance of the disease and save the crop from the weeds.
The basic aim is to summarize the medicinal importance of onions. Allium cepa is highly valued for its therapeutic properties. Research indications shows that onion may help guard against various chronic diseases and disorders. Thats possibly because onions comprises of substantial quantities of the flavonoid quercetin.
Quercetin can subsidize to inhibiting damaged cells from proceeding to cancer. Flavonoids also have anti-inflammatory properties. In addition, onions contain Organo-sulfur compounds that are naturally occurring chemicals detoxify carcinogens, stopstumor cell development and prevent swellings from gaining a blood supply and help to inhibit the formation of blood clots.
Antioxidant activity of Onion: Anthocyan in pigments, determined in the external covering of red cultivar onions, are only slight ingredients of the appetizing portion. Kaempferol, though demonstrable in onion varieties, existing in much lesser amounts than quercetin. Consequently, quercetin is the chief flavonoid of attention in onions.
Anticancer activity: Numerous researchers have recommended that Onion ingestion may have a strong influence on stomach tumor inhibition. High consumption of Allium cepa more than 0.5g per day was associated with compact risk of abdominal cancer elsewhere the cardiac also high consumption of Allium cepa may reduce the risk of “Helicobacter pylori” infection, which has been related to abdominal tumor through ulcer establishment. There is likely an inhibitory effect on lung tumor risk from intake of onions, but it is mysterious if the levels desired are achievable to consume. A substantial reduction in risk of breast tumor with high ingestion more than 16 times per week of onions is reported.
Dosage of Onion: Most of the human studies that have displayed an influence from onion consumptions at least 25g per day and frequently increasing that amount 2 to 4 times. However various studies have found that cooked onions are most acceptable, many studies recommended that onion ingredients are ruined by cooking and that raw or fresh onions are perhaps most active. If a mixture, extract, syrup or oil is used, 1 tablespoon three times per day then it may be essential for some months before effects are noted.
Muhammad Parvaiz is botanist by profession and did his BS (Hons.) from University of Gujrat, Pakistan. He has published many research papers in well reputed national and international journals and also co‐author of one book published internationally entitled as “Introductory Plant Taxonomy”.
Sikandar K. Sherwani is renowned microbiologist of Pakistan. He has more than 100 research papers on his credit in the area of Clinical microbiology and medicinal plants. He has received man national and international awards for his academics and research achievements. He is a frequent writer in many scientific magazines.