Increasing planting early crops on the wetland is an effective measure to fully utilize the spring season resources of temperature or light and raise multiplecrop index.
攀西地区下湿田增种早春作物，是充分利用春季光温资源，提高复种指数的有效措施。
2
A study of the rice genome suggests that the crop was domesticated only once, rather than at multiple times in different places.