Wheat individual grain-size variance originates from crop development and from specific genetic determinism

Area of Science:

• Plant Science
• Agricultural Science
• Genetics

Background:

• Wheat grain yield is typically analyzed through components like spike number and thousand kernel weight (TKW).
• Climate change and abiotic stresses increasingly impact TKW, making it a key breeding target.
• Current analyses of TKW overlook the significant variation in individual grain mass within genotypes.

Purpose of the Study:

• To investigate the factors determining the variance of individual grain size in wheat.
• To explore the genetic basis and environmental influences on individual grain size variation.
• To identify potential targets for wheat breeding aimed at improving grain yield stability.

Main Methods:

• Measured yield components and individual grain size variance in two diverse wheat panels across two environments.
• Conducted a genome-wide association study (GWAS) using a dense SNP array.
• Analyzed correlations between canopy structure, spike number, and grain size variance.

Main Results:

• Individual grain size variance is partly influenced by pre-flowering yield components, particularly canopy structure and spike density.
• A specific genetic basis for grain size variance was identified, independent of other yield components.
• Genome-wide analysis revealed significant quantitative trait loci (QTL) affecting individual grain size variance.

Conclusions:

• Manipulating canopy structure can influence individual grain size variance.
• Specific chromosomal regions harbor genes that control grain size variance, offering novel breeding avenues.
• Focusing on individual grain size variance, alongside TKW, can enhance wheat breeding strategies for climate resilience.