Rice is divided into indica rice and japonica rice, early rice and middle and late rice, glutinous rice and non-glutinous rice according to rice type. Divided into conventional rice and hybrid rice according to the way of seed retention. There are other classifications, which are divided into rice and floating rice according to whether there is soilless culture or not; According to the life cycle, it is divided into seasonal rice and lazy rice; According to the height, it is divided into ordinary rice and giant rice about 2 meters; According to salt tolerance and alkalinity, it can be divided into common light rice and "sea rice".
Extended data:
growing environment
1. Rice likes high temperature, high humidity and short sunshine, and has low requirements for soil, but paddy soil is the best.
2. The lowest temperature of seedling germination is 10 ~ 12℃, and the optimum temperature is 28 ~ 32℃. The average daily temperature at tillering stage is above 20℃, and the optimum temperature for ear differentiation is around 30℃. Low temperature prolonged the differentiation of branches and glumes. The optimum heading temperature is 25 ~ 35℃. The optimum flowering temperature is about 30℃, lower than 20℃ or higher than 40℃, and pollination is seriously affected.
3. The relative humidity is 50 ~ 90%. The key period of fruiting is from panicle differentiation to full filling stage; The population with balanced nutritional status and high photosynthetic efficiency is of great significance to improve seed setting rate and grain weight. A lot of water and mineral nutrients are needed at heading and fruiting stage; At the same time, it is necessary to enhance the root activity and prolong the functional period of stems and leaves. It takes about 500 ~ 800 kg of water to form 1 kg of rice.