the Symposium on Wheats for More Tropical Environments - cimmyt

300is unique and is not presently followedby any o<strong>the</strong>r corporation in <strong>the</strong>country. although <strong>the</strong>re is an awarenessthat such a system should be adoptedby o<strong>the</strong>rs.The grow-out test of about 20% of <strong>the</strong>certified seed lots is carried out toascertain <strong>the</strong> quality of seed marketedby <strong>the</strong> corporation. To pin-pointmistakes in production. processing andmarketing. <strong>the</strong> identity of seed ofdifferent farmers is maintained byallocating separate seed lots.StorageThe moisture content of seed is a veryimportant factor. influencing itslongevity in storage. Wheat seed isharvested during <strong>the</strong> dry part of <strong>the</strong>year (April and May). when moisturecontent is low. However. mechanicaldrying becomes necessary when seedsget wet due to rains at <strong>the</strong> maturitystage. Wheat seed is stored over <strong>the</strong>monsoon. when relative humidity ishigh. until <strong>the</strong> planting season inNovember and December. During thisperiod. seed is likely to take upmoisture. and it deteriorates if notproperly stored. Because of this fact.<strong>the</strong> corporation has chosencomparatively drier places for storage.and also uses polyethylene-lined bagsfor mOisture-proof packaging.Pests are a real threat to proper seedstorage in India. The rice weevil(Sitophilus oryzae). <strong>the</strong> lesser grainborer (Rhizopertha domtntca). <strong>the</strong>Khapra beetle (Trogoderma granarium)and <strong>the</strong> rust flour beetle (Triboltumcastaneum) infest wheat seed duringstorage. To eliminate pests. fumigationwith aluminum phosphide is carriedout once a month and spraying withpesticides once every two weeks. Whilefumigating <strong>the</strong> seed stock. precaution istaken that moisture content in <strong>the</strong> seedis below 14%. as fumigation at a highermoisture content damages <strong>the</strong> seed.Wheat seed is also invaded bypathogens during storage, <strong>the</strong> mostcommon being Aspergillus. To avoiddamage by fungi. <strong>the</strong> seed is treatedwith fungicides.To avoid moisture penetration through<strong>the</strong> floor. seed bags are stored onwooden pallets after laying a vaporbarrier. Proper ventilation andinsulation are prOVided to lower heat in<strong>the</strong> warehouses. When seed is stored inmetal bins. frequent aeration by meansof a blower is carried out to remove anyheat generated inside <strong>the</strong> seed columns.The government is currently puttinggreater emphasis on creating properstorage facilities to avoid damage toseed during storage. Under thisprogram. bulk seed storage warehouseswill be constructed withoutrefrigeration or dehumidifyingequipment: for storage of breeder andfoundation seed. such equipment isbeing planned.MarketingThe demand for wheat seed in <strong>the</strong>country is growing extremely rapidly.This increase in demand is by nomeans accidental or temporary. Since<strong>the</strong> new varieties of wheat are shorterin duration and relatively insensitive today length. many areas where wheatcultivation was Virtually unknown.West Bengal. Assam. Tripura andMeghalaya in <strong>the</strong> east and Kamatakaand Maharashtra in <strong>the</strong> south. havebecome important wheat-growing areas.The cultivation of wheat in Bangladeshhas also assumed importance.Assessment of demandUntil recently. data on seed demandhas been inadequate. Sometimesdemand has exceeded supply andsometimes seed of certain varieties hasgone unsold. Under <strong>the</strong> National SeedProgram.- <strong>the</strong> government is nowholding seed conferences well before<strong>the</strong> beginning of each new plantingseason. and <strong>the</strong> seed demand andsupply for <strong>the</strong> different states is