Analysis of trait heritability in functionally partitioned rice genomes

Area of Science:

• Plant genetics
• Agronomy
• Genomics

Background:

• Understanding the genetic basis of agronomic traits in rice (Oryza sativa L.) is key for accelerating genetic improvement.
• Genome-wide association studies (GWAS) have identified single nucleotide polymorphisms (SNPs) linked to agronomic traits, but their distribution and roles in different genomic regions are unclear.

Purpose of the Study:

• To compare the genetic contributions of functionally distinct genomic regions to five key agronomic traits in rice.
• To determine whether genic or non-genic regions are more influential in trait heritability and phenotypic variation.

Main Methods:

• Analysis of a natural rice population (524 accessions) using 3,616,597 SNPs.
• Heritability analysis partitioned across functionally distinct genomic regions (genic, non-genic, regulatory, intergenic).
• Comparison of genetic effects and predictabilities of SNPs located in genic versus non-genic regions.

Main Results:

• Regulatory and intergenic regions accounted for the majority of trait heritability.
• Most trait-associated SNPs (TASs) were found in non-genic regions, exhibiting greater genetic effects than those in genic regions.
• Non-genic regions demonstrated higher predictability for agronomic traits compared to genic regions.

Conclusions:

• Non-genic regions play a more significant role than genic regions in rice trait heritability and phenotypic variation.
• Findings provide insights into the genetic architecture of rice agronomic traits and suggest a focus on non-genic regions for genomic selection.
• Results align with similar findings in humans and maize, highlighting the broad importance of non-genic regions in trait determination.