| It is an important approach in rational utilizing resources ,decreasing environmental pollution and reducing inputs that exploiting plant descendible characterize and potential of water and nutrients use , cultivating or utilizing genotypewith high water and nutrition useefficiency . The field plot experiments were conducted to study on genotypic variation and physiological mechanism of 10 summer maize varieties that is typical in local agricultural production in water and nitrogen use efficiency by analyzing biological yield and grain yield,water and nitrogen use efficiency ,dry matter and nitrogen accumulation and distribution in plant after flowering, some physiological items such as leaf chlorophyll content, nitrate reduce enzyme activity and photosynthesis characteristics and so forth. So that the scientific basis will be provided for further selecting and breeding the genotypes with higher water and nitrogen use efficiency .The main results are as follows:1. There are significant differences of dry matter and grain yield and different sensitivity to nitrogen amongsummer maize cultivars tested. Under condition of high nitrogen application and no nitrogen application, variable co-efficient were 8.73%and 21.05% respectively. Under condition of no nitrogen application, grain was determined by numbers of spike of hectare, butunder condition of high nitrogen application, by the 1000-kernel-weight that was increased by nitrogen2. The tested maize varieties could be classified into four different types based on their nitrogen efficiency and two different types based on nitrogen responsiveness. There were different type of nitrogen efficiency and type of nitrogen response among maize cultivars in different nitrogen level, and there was no relationship between them3. Nitrogen accumulation couldn't reflecte the type of nitrogen efficiency, and nitrogen useefficiency could reflecte it very wellunder condition of no nitrogen application; but not under condition of medium nitrogen application and high nitrogen application. Nitrogen harvest index could reflected the type of nitrogen efficiency under condition of no nitrogen application and high nitrogen application, but not under condition of medium nitrogen... |
