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5.3.2. Preparing the land Before plowing, tall grasses, stubbles, and thorny weeds in the field have to be removed. They may injure the plowman and interfere with plowing. After plowing once, the plowed field should be harrowed 2-3 times. plowing, harrowing 참조

5.3.1. Selecting the appropriate location The seedbed should be conveniently located for irrigation and drainage. It should be safe from flood. The seedbed should be fertile, exposed to full sunlight, and accessible to the farmers. The seedbed site should be far from fields infected with several diseases. It should not be lighted at night to avoid attracting insects. 가운데 야자수 없애..

5.2. Methods of raising seedlings The major methods of raising seedlings are the wetbed and the drybed. The wetbed method is most often used by farmers. The drybed method is preferred for rainfed lowland areas where the frequency and amount of rainfall during the planting season are unpredictable.

5.1.3. Incubating Incubating is the second of two steps in pregerminating seeds. The soaked seeds are washed with fresh water to remove odor. The seeds in cloth bag or gunny sack are placed in an appropriate container. At normal room temperature 27℃, the incubation time of seeds intended for wetbed or direct seeding must be 24 hours. For a dapog seedbed, the time must be 36-..

5.1.2. Soaking Soaking is the first of two steps in pregerminating seeds. pregerminated seeds are less affected by pests in the fields because they start to grow quickly. Seeds are soaked in fresh water in a bucket or drum at temperature 27℃ for 24 hours, 25℃ for 48 hours, and 22℃ for 72 hours. The water should be changed every 5-6 hours during soaking period. Remove and discard unfilled ..

5.1.1. Breaking dormancy Dormancy of rice seeds can be broken by heat or nitric acid treatments. Before treatment, the rice seeds should be dried and cleaned to remove unfilled spikelets, straw, and other foreign matters. The rice seeds are placed in a oven maintaining the temperature at 49 to 50℃. Moderately dormant varieties require 4-5 days while strongly dormant varieties may require 7-10..

3.7.5. Causes of empty spikelets Many factors can affect the filling of spikelets. Lodging, low light intensity, drying of the leaves, disease, or insect damage can cause a lack of starch. High temperature or dry winds can cause the stigma to dry and no fertilization to occur. Too much nitrogen at panicle formation can prevent normal spikelet devellopment. Low temperature or high humidity at fl..

3.7.4. Stages of grain formation Buildup of starch inside the spikelet begins after part of the male cell unites with the egg cell in the ovary which is called " fertilization". The milky grain pops when pressed between fingers and leaves white liquid. The milky grain turns into soft dough and later into hard dough. The spikelet reaches maximum weight 21 days after fertilization.

3.7.3. Flowering order of a panicle As the lemma and palea open and the anthers protrude, the shedding of the pollen grains immediately follows. It takes about 7 days for all of the spikelets in a panicle to open. The upper spikelets ( number 1 ) open first. The lower spikelets open last. They usually do not completely fill in large panicle. Modern varieties have 100-120 spikelets per panicle.

3.7.2. The opening of spikelet Some anthers begine to open one day after the panicle comes out. When the spikelet opens, the anthers inside the spikelet will also open. Low temperature delays the opening of the anthers. The pollen, Which is male cells like a fine dust, comes from the anthers. It must reach the stigma and unite with the egg inside the ovary before a grain can develop. A grain is..