Response of Source-Sink Characteristics and Rice Quality to High Natural Field Temperature During Reproductive Stage...

Area of Science:

• Agronomy
• Plant Physiology
• Food Science

Background:

• Global warming impacts rice development and quality.
• The specific effects of high temperatures during the reproductive stage on rice quality are not well understood.

Purpose of the Study:

• To compare grain filling dynamics, source-sink characteristics, and quality traits under normal (low temperature) and hot (high temperature) conditions during rice's reproductive stage.

Main Methods:

• Comparison of rice growth under two contrasting temperature regimes: normal (low temperature) and hot (high temperature) growth seasons.
• Analysis of grain filling dynamics, source-sink relationships (leaf area index, specific leaf weight, leaf-sink ratio, stem-sink ratio), and quality-related traits (chalkiness, protein content, starch content, pasting properties).

Main Results:

• High temperature significantly increased chalky grain rate and level, protein content, pasting temperature, setback, and consistency.
• High temperature decreased total starch content, leaf area index, specific leaf weight, and source-sink ratios.
• High temperature shortened the active grain filling period and reduced dry matter translocation to grains.

Conclusions:

• High temperatures during the reproductive stage reduce rice quality by impairing assimilate translocation, shortening grain filling duration, and increasing chalkiness.
• Source-sink characteristics are modulated by high temperatures, leading to poor rice quality (high chalkiness, inferior eating and cooking quality).
• Findings provide a reference for selecting heat-tolerant varieties and managing rice quality under high-temperature stress.