Optimizing panicle fertilizer application based on amylose content for balancing yield and quality of japonica rice

Panicle nitrogen application is a key agronomic practice for regulating rice yield and quality, yet its effects are highly dependent on genetic background, especially the amylose content of japonica rice varieties.

This study systematically examined the differential responses to panicle nitrogen fertilizer (0, 60, 120 kg N ha^-1) in yield formation, grain quality, and starch properties among representative japonica rice genotypes differing in amylose content (normal vs. low).

Results revealed variety-specific regulatory patterns: normal-amylose content (NAC) varieties showed a stronger yield response, with a 27.27% increase under the N120 treatment, largely attributable to higher panicle number per unit area. However, these varieties also exhibited significant deterioration in appearance quality, such as increased chalkiness. In contrast, low-amylose content (LAC) varieties demonstrated a greater improvement in milling quality-head rice rate increased by 10.13% under N120-but a more pronounced decline in cooking/eating quality, evidenced by reduced peak viscosity, breakdown value, and taste score. These findings highlight the need for amylose-based differential nitrogen management strategies to simultaneously achieve high yield and superior quality, providing a theoretical foundation for precision rice production oriented toward "variety-specific cultivation and quality-targeted fertilization."