Genetic Analysis of the Awn Length Gene in the Rice Chromosome Segment Substitution Line CSSL29

Area of Science:

• Plant genetics
• Agronomy
• Crop science

Background:

• Awn length is a crucial agronomic trait in rice, influencing yield and quality.
• Understanding the genetic basis of awn length is essential for rice breeding programs.

Purpose of the Study:

• To investigate the genetic mechanisms underlying awn length variation in rice.
• To identify quantitative trait loci (QTLs) and candidate genes controlling awn length in a specific chromosome segment substitution line (CSSL29).

Main Methods:

• Construction of an F2 segregated population from a cross between 9311 and CSSL29.
• Quantitative trait loci sequencing (QTL-seq) for major QTL identification.
• Yeast two-hybrid assays to analyze gene interactions.
• Analysis of rice population databases (3k and 10k).

Main Results:

• A major QTL, qAWN4, associated with rice awn length was identified on chromosome 4, containing the gene An-2.
• The awn length gene An-1 was also found in the CSSL29 substitution segment.
• Both An-1 and An-2 genes demonstrated an additive effect on the long-awn phenotype, with no direct protein interaction.
• Population genetic analysis revealed artificial selection of the An-2 allele during rice domestication.

Conclusions:

• Multiple genes, including An-1 and An-2, contribute to rice awn length regulation through additive effects.
• The findings provide insights into the genetic control of awn length and its role in rice domestication.
• This research lays the foundation for future studies on awn development and breeding strategies for long-awned rice varieties.