poor digestion, so if it is overfed with fertilizer, it would suffer from diarrhea. However, after analyzing the photosynthesis of rice using an infra-red gas analysis machine which had been developed at the time by mainly Japanese biologists in IRRI, it was later clarified that the yield was poor because the rice leaves became too big, as its nutrient intake ability was actually rather better than previously thought, and the plants fell down making it difficult to bear fruit.
Another important feature of the traditional varieties in the tropics is although planting takes place in the dry season from January to February, flowers don't bloom till September/October, by which time the daylight is shorter, as its sensitivity to light is very acute. If there is enough water, rice can be produced in the dry season and a much higher yield can be expected as the solar energy is more powerful than during the rainy season, but because it takes so long to grow, eventually it has been produced in the rainy season which has sufficient water.
Also, for the traditional varieties produced in the rainy season, it used to take 160-180 days before harvesting. So for those reasons, there was usually only one crop of the traditional varieties per year.
2. Character of the Modern Varieties and its Development (3)
As a result of research by IRRI, it was established that solar energy can be better harnessed by changing the shape of the rice. In other words, if the rice form is improved so that the head (ear) is shorter and thicker, and the leaf stands more upright to receive the sunshine, and by developing a shape which strengthens an offshoot, then if it is fed more fertilizer, the yield of rice will be increased by gathering the sun's rays more effectively.
Also, if rice is planted in the dry season, high yield can be expected as the solar energy is sufficient, but irrigation facilities are needed to enable production in the dry season as much water is needed for rice. Also, if it is very light sensitive, as are the ordinary varieties, the flower doesn't bloom until September/October when the daylight becomes shorter, so if the growing period can be
