Increased panicle nitrogen application improves rice yield by alleviating high-temperature damage during panicle...

Area of Science:

• Agronomy
• Plant Physiology
• Crop Science

Background:

• Rice grain yield is linked to spikelet fertility, which is sensitive to high temperatures.
• Nitrogen (N) is vital for rice yield formation, but its role under heat stress needs further investigation.

Purpose of the Study:

• To determine how panicle nitrogen application impacts rice yield formation under high temperatures during the critical panicle initiation stage.
• To compare the effects of heat stress and nitrogen management on heat-susceptible (Liangyoupeijiu) and heat-tolerant (Shanyou63) rice varieties.

Main Methods:

• Two rice varieties were subjected to high temperature (HT) or control temperature during panicle initiation.
• Low panicle nitrogen (LPN) and high panicle nitrogen (HPN) treatments were applied.
• Grain yield, spikelet fertility, anther and pollen development, and panicle temperature were analyzed.

Main Results:

• High temperatures significantly reduced grain yield, with greater losses at LPN compared to HPN in both varieties.
• Heat stress impaired anther development and pollen viability, leading to reduced spikelet fertility.
• High panicle nitrogen application mitigated yield loss by improving anther development, pollen viability, and spikelet fertility, especially in the heat-susceptible variety.
• HPN also led to a slight decrease in panicle temperature under heat stress due to increased evapotranspiration.

Conclusions:

• Increased panicle nitrogen application is a promising strategy to enhance rice resilience against high-temperature stress.
• Optimizing nitrogen management can improve anther and pollen development, leading to reduced yield losses in rice under heat stress conditions.
• The findings highlight the potential of targeted nitrogen application to safeguard rice production in a changing climate.