Construction of Rice Under Dry Cultivation Dominant Population by Interaction of Seeding Rate and Nitrogen Rate

Abstract

In order to construct the dominant population of rice under dry cultivation, the external characteristics of the population and the photosynthetic physiological characteristics of the upper three leaves were investigated. In this study, a double factor interaction method of seeding rate and nitrogen rate was used to construct the dominant population of rice under dry cultivation. We determined 195 kg·ha-1 seeding rate and 140 kg·ha-1 nitrogen rate as the appropriate configuration. To achieve high yield, high nitrogen utilization and moderate morphological characteristics by coordinating the comprehensive advantages of population spike number and spike grain number, and to increase the photosynthetic potential of the population by coordinating the reasonable distribution of light energy in the upper three leaves to construct the dominant population of rice under dry cultivation. Photosynthetic potential of 105.55m2·d/m2, light energy interception rate of 31.21% in the inverted second leaf and plant height of 101 cm at 10 days after flowering were important external characteristics of the dominant population of rice under dry cultivation. The ability of the inverted second leaf to intercept light energy is the basis for ensuring the photosynthesis of the population. The simultaneous coordination of photosynthetic enzyme activity, net photosynthetic rate and chlorophyll content in the inverted second leaf is an important physiological characteristic of the photosynthetically dominant group. The variation of photosynthetic physiological indexes in the inverted second leaf was characterized by ‘from genes to enzyme activity to net photosynthetic rate and chlorophyll, and the spatial variation was from the upper leaves to the lower leaves’. ‘ Protect the flag, promote the second, stabilize the third ’ (Maintaining photosynthetic capacity of the flag leaf , promoting photosynthetic enzyme activity in the inverted second leaf, and stabilizing photosynthetic gene expression in the inverted third leaf ) is an important tool to construct the dominant population of rice under dry cultivation. These studies have significant implications for the future construction of dominant rice under dry cultivation in different regions and provide an important basis for the study of the regulatory mechanisms of photosynthetic pathways in different leaf positions.