Mutations in the dwarf3 gene confer height stability in sorghum

Area of Science:

• Plant genetics
• Crop science
• Molecular biology

Background:

• Dwarfism in crops enhances lodging resistance and harvest index.
• The sorghum dw3-ref allele has an unstable tandem duplication, leading to wild-type reversion.
• Stable dwarf alleles are needed for consistent crop improvement.

Purpose of the Study:

• Identify stable alleles of the sorghum dw3 gene.
• Develop sorghum lines with improved height stability for breeding.
• Characterize new dw3 alleles for potential use in crop improvement.

Main Methods:

• Screening sorghum conversion lines using PCR for the dw3-ref tandem duplication.
• Sanger sequencing to analyze DNA sequences of non-duplication genotypes.
• Field trials to assess stability and agronomic traits of new alleles and backcrossed progeny.

Main Results:

• Identified three indel mutations (82 bp deletion, 6 bp duplication, 15 bp deletion) in the dw3 gene.
• New alleles dw3-sd3, dw3-sd4, and dw3-sd5 showed no wild-type reversion in field trials.
• Backcrossed progeny exhibited stable dwarfism with similar or improved plant height and flowering time.

Conclusions:

• The stable dw3-sd3, dw3-sd4, and dw3-sd5 alleles are valuable for breeding stable dwarf sorghum.
• These alleles offer a reliable genetic tool for enhancing crop lodging resistance and harvest index.
• The findings contribute to developing more robust and efficient sorghum varieties.