CHAPTER ONE
1.0    INTRODUCTION
1.1 BACKGROUND INFORMATION
          Onions is a vegetable crop and ancient in nature if is through to have been domesticated in the central Asia. It is one of the oldest vegetable cultivated by man for food. In the world onion buld are found in ancient Egypt, India, China and Europe during the middle ages, and in the late sixteenth or early seventeenths centuries, it spread to the new world by the Spaniards. The crop is now wide spread in both temperate and tropical regions with Europe as the largest producers (cobley and Steele, 1976).
          In the tropic most onions are grown with irrigation during the relatively cool dry season in semi arid region, they are not good crop for hot wet tropic. Onions can be grown under a wide range of climatic condition but they succeed best in a mild climate without excessive rainfall or great extremes of heat and cold. They are not suitable to regions with heavy rainfall in the lowland humid tropics. Cool conditions with an adequate moisture supply are most suitable for early growth followed by warm drier condition for maturation, harvesting and curing. They can be grown on a variety of soils, but the soil should be retentive of water, non – packing and rich in nutrient, a good fertile loam usually gives the best result. They may be grown successfully on peat soils. The soil optimum pH is about 6.0 – 7.0 (alkaline) (carl and Hall, 1986).
          In storage a specific environment must be provided for the onions, if a high quality product is to result. Storage losses are a function of storage environment as well as the condition and cultural practices used during the growing season. Proper control of storage environment can however, significantly extend the storage season from that which would result from storage environment that were not matched to the condition of the onions when placed in storage (carl & Hall, 1986).
          Onions may be stored in bulk or may be placed in palletised bins that are stacked in a storage structure. The use of bins may make handling of onions convenient but it does make ventilation of the onions more difficult. Improved bins design may alleviate the ventilation problems in future (cobley and Steele, 1976).
          Onions are packed locally by using basket and jute bags these packaging material come locally from palm; bamboo and fibrous jute trees, also they have different sorts and sizes. These packaging materials have the function for transportation and storability of the onions. Again these packaging material are locally available and relatively cheap. Apart from these few advantages mentioned they have no barrier to dust, not suitable for measuring weight and can easily be crushed which might lead to damage of the onions.