Regulation of Rice Grain Quality by Exogenous Kinetin During Grain-Filling Period

Area of Science:

• Plant Physiology
• Agricultural Science
• Molecular Biology

Background:

• Cytokinins (CKs) are crucial plant hormones regulating growth, development, and stress responses.
• The specific role of CKs in modulating rice grain quality remains largely unexplored.
• Understanding CKs' impact on rice quality can lead to improved crop yields and nutritional value.

Purpose of the Study:

• To investigate the effect of exogenous kinetin (KT) on rice grain quality.
• To determine if KT application influences physiological traits and gene expression related to starch synthesis.
• To identify optimal KT concentrations for enhancing rice grain characteristics.

Main Methods:

• Exogenous application of varying kinetin (KT) concentrations to rice plants during the grain-filling stage.
• Assessment of physical grain quality parameters, including thousand-grain weight, chalkiness, and chalky grain rate.
• Evaluation of eating and cooking qualities using gel consistency (GC) and alkali spreading value (ASV).
• Analysis of the transcription levels of starch synthesis-related genes.

Main Results:

• All tested KT concentrations significantly increased thousand-grain weight.
• The 10⁻⁸ M KT treatment notably reduced chalkiness and chalky grain rate.
• 10⁻⁸ M KT significantly enhanced gel consistency (GC) and alkali spreading value (ASV).
• 10⁻⁸ M KT positively influenced the expression of specific starch synthesis genes, unlike the 10⁻⁵ M treatment.

Conclusions:

• Exogenous application of appropriate KT concentrations during grain filling improves rice grain quality.
• KT influences rice grain quality by modulating appearance quality (AQ) and eating and cooking qualities (ECQ).
• KT's effects on grain quality are linked to the regulation of starch synthesis pathways and gene expression.