the Symposium on Wheats for More Tropical Environments - cimmyt

295Storage in 20-liter biscuit or kerosenetins is very effective. They have <strong>the</strong>advantage of smaller capacity (18 kg)and lower price (US$ 1). Unlike o<strong>the</strong>rcontainers. seed can be placed in tincontainers immediately after sun drying(i.e.• without overnight cooling). Since<strong>the</strong> tin is thin and is a good heatconductor. <strong>the</strong> heat is quicklydispersed.The insertion of a double plastic baginside fertilizer or gunny sacks alsomakes <strong>the</strong>m useful for seed storage;germination of over 80% may bemaintained in <strong>the</strong>se bags. Their storagecapacity (about 37 to 74 kg) meets <strong>the</strong>requirements of <strong>the</strong> average farmer.and <strong>the</strong>y are very cheap and generallyaVailable. However. for protectionagainst rats. <strong>the</strong> bags should be keptwithin ear<strong>the</strong>n containers or onsuspended platforms (5).Wheat seed is also kept in bamboo andmud storehouses (kuti); <strong>the</strong>se are usedfor rice storage but do not adequatelyprevent dampness. Ear<strong>the</strong>n pots arealso occasionally used. but do notprevent dampness ei<strong>the</strong>r due to <strong>the</strong>irporosity. Such containers should becoated with tar and sealed for mosteffective use. If containers are relativelyairtight. <strong>the</strong>re is no need to redry <strong>the</strong>seed during <strong>the</strong> storage period;o<strong>the</strong>rwise. seed should be dried five tosix times.A survey conducted in 1982 indicatedthat about 12% of <strong>the</strong> seed samplescollected had been treated withinsecticides. Some farmers use naturalinsecticides such as nim. biskatali andtobacco leaves as insect repellants.Fur<strong>the</strong>r research is needed to determine<strong>the</strong> efficacy of natural insecticides incontrolling insects in stored seed.Seed corporation storageTaking into account <strong>the</strong> adverseenvironmental conditions for any typeof seed storage in <strong>the</strong> tropiCS. only acombination of recommended practices,well-maintained storage facilities andcareful seed packaging will guaranteethat, once harvested. high quality seedwill reach <strong>the</strong> farmer without loss ofViability. The seed processing centershould be proVided with moisture-proofseed storage. with <strong>the</strong> capacity to store<strong>the</strong> total quantity of seed produced. InBangladesh. seed is stored in gunnysacks for ease of handling but. since <strong>the</strong>duration of storage is usually sixmonths. <strong>the</strong> bagged seed is periodicallydried by forced-air drying; germinationis checked frequently.Control of pests and diseasesPests which have to be controlled instorage include rodents and insects.Specific measures should beundertaken in buildings used forstorage to prevent <strong>the</strong> entry of rats;insects are more difficult to control.Insects live in cracks and crevices ofbuildings. in old bags and may alsocome from <strong>the</strong> field with <strong>the</strong> seed.Floors and walls can be sprayed withappropriate long-term residualinsecticides for control. In Bangladesh.insecticides are not used for treatingseed. since leftover or unused seed maybe used by <strong>the</strong> farmer for consumption.Hence. fumigation by Phostoxin is doneas a regular practice.Seed DistributionDistribution by<strong>the</strong> seed corporationThe price of seed is fixed by <strong>the</strong>Bangladesh Government prior todistribution. The seed is bagged. sent todistribution points and. finally. sold togrowers. An excessively high price ofseed will discourage <strong>the</strong> farmers fromplanting wheat. while an excessivelylow price will encourage <strong>the</strong> misuse ofcostly seed for consumption and alsodiscourage on-farm preservation.,InBangladesh. <strong>the</strong> price of wheat seedsupplied by <strong>the</strong> seed corporation is