A recent study by Wang et al., published in BMC Plant Biology, examines the genetics of rice grain shape, a trait which effects both the yield and quality of rice. Researchers used a genome-wide association study with 265 rice accessions that were grown over two years to analyze over 4.4 million genetic markers to identify genes that influence grain length, grain width, and the grain length-to-width ratio.
The researchers found 61 genetic regions that influence variation (quantitative trait loci) associated with grain shape, including multiple that appeared with consistency in both study years. Three were linked to grain length, one to grain width, and eleven to grain shape ratio. They also identified three candidate genes:
- LOC_Os03g39710, a monosaccharide transporter linked to grain length
- LOC_Os05g09480, an auxin-responsive gene (OsIAA16) linked to grain width
- LOC_Os09g36350, a glycoside hydrolase associated with the grain length-width ratio
The phenotypic variety in the studied rice was wide, which confirms there is strong genetic diversity to allow for breeding analysis. Results suggest that the identified genes control the shape of the grain, opening up the ability to attempt genetic engineering for precision selection of high yield, high quality rice varieties. The genes identified in the study may help breeders design rice plants with optimized grain size and shape, improving both market value and food security as global rice demand continues to rise.