The researchers studied how different rice varieties respond to different levels of nitrogen fertilizer. They found that applying nitrogen fertilizer can increase rice yield by improving the number of effective panicles and filled grains per panicle. One variety, OM052, showed the highest grain yield and nitrogen use efficiency, making it a high-efficiency variety. Nitrogen application also affected rice quality, increasing amylose and protein content while reducing chalkiness. Overall, proper nitrogen application can boost rice yield, improve quality, and ensure high productivity and quality together.