From the morphological characteristics and economic characters, generally indica rice has strong tillering ability, short first panicle node, light leaf color, more hairs on the leaves, slender seeds, short, hard and straight hairs, and the shell color is blue and white when heading, which is easy to thresh. Indica rice generally has high amylose content, high cooking expansibility and low viscosity. Generally speaking, japonica rice is inferior to indica rice in tillering ability. The first ear is long, the leaves are dark, the leaves are hairless, the grains are short and round (a few japonica rice varieties also have long grain shapes), the barnyard grass is long, messy and soft, and the shell is green when heading, which is not easy to thresh. The content of amylose in japonica rice is low, and the rice quality is sticky.
From the physiological characteristics and adaptability, indica rice generally has strong fertility and poor cold tolerance, and can germinate only when the daily average temperature is above 65438 02℃, so indica rice has good adaptability. Japonica rice has strong fertilizer tolerance, but poor fertilizer absorption, and strong cold tolerance. It can only germinate when the average daily temperature reaches 10℃, and its adaptability is poor. Under suitable temperature conditions, the photosynthetic rate of indica rice leaves is higher than that of japonica rice, with good luxuriance, easy to grow early and rapid development.
Geographically, indica rice is suitable for planting in hot and humid areas with low latitude and low altitude, such as southern China. Japonica rice is suitable for planting in high latitude and high altitude areas, such as northeast, north and northwest rice areas in China, high altitude rice areas in Yunnan-Guizhou Plateau and mixed cropping areas of single-season rice and double-season rice in the middle and lower reaches of the Yangtze River.