Novel Allelic Mutations in Dw3 Gene That Affect the Height of Sorghum Plants

Breeding for dwarfing traits in sorghum is crucial. However, only three genes (<i>Dw1</i>-<i>Dw3</i>) that control plant height have been mapped. In this study, 634 sorghum cultivars were collected to investigate plant height and genotypes. Four were genotyped <i>Dw1DW2Dw3</i> (wild type) but with different plant heights, and they were selected to construct two populations and map new dwarf genes. Bulked segregant analysis with whole-genome resequencing of the two populations identified the candidate gene in one same genomic region-on chromosome 7. Then, it was narrowed down to a region containing nine genes. Amino acid and DNA sequence analysis of the parent and offspring plants revealed that two novel allelic mutations in the <i>Dw3</i> gene play a role in reducing the plant height-8R262 or 8R417, including 1 bp substitution and 2 bp deletions. Furthermore, we sequenced 19 cultivars that primarily exhibited a "one-dwarf" hybrid or wild-type and presumed another allelic mutation via the amino acid alignment of 8R019, 8R100, and 8R402, which was another one-base substitution. These results indicate that multiple types of allelic mutations in the <i>Dw3</i> gene should be considered when identified or applied.