The effect of postponing nitrogen application on grain yield and the panicle-grain structure in mid-season hybrid rice in southwest China Regional yield variations and optimized application amounts of nitrogen of mid-season hybrid rice in Southwest China Effects of High Temperature during Flowering Period on Seed Setting Rate and Its Relationship with Sink to Source Ratios and Flowering Habit of Mid-season Hybrid Rice Relationship between the Efficient Amount of Nitrogen Application for Grain Filling and the SPAD Value at Full Panicle Stage in Mid-Season Hybrid Rice Correlation of Ratooning Ability with Its Main Crop Agronomic Traits in Mid-season Hybrid Rice Adaptation of Mid-season Hybrid Rice to the Intensive Cultivate System in Winter Water-logged Field Characteristics of Nutrient Uptake and Utilization of Mid-Season Hybrid Rice under Different Nitrogen Application Rates in Different Locations of Southwest China