The discovery of gene variants that increase rice grain length and quality is reported in two independent papers published online this week in Nature Genetics. Rice breeders may be able to use the desirable version of this gene in combination with other gene variants known to affect rice grain length, quality, and yield to breed improved strains of rice.
Higher quality rice typically has lower chalkiness and is enriched for other desirable characteristics, within a given market, such as those related to cooking time, texture, and color. While many genes have been identified that can increase grain yield, there are far fewer genes known that breeders can use to control other aspects of rice quality. Two groups, working independently, have now discovered mutations in a gene known as LOC_ Os07g41200 that produce longer, more slender grains with less chalkiness. This increase in quality did not come at the expense of yield.
Xiangdong Fu and colleagues crossed two varieties of rice, one considered to be of mediocre quality and one of excellent quality, to locate the genes responsible for better quality. They found that the gene variant from the “excellent” variety was expressed at higher levels, and this correlated to more slender grains.
In a separate study, Jiayang Li and colleagues used a similar approach with different rice varieties to locate the gene for improved quality. In their study, a duplication within the gene caused higher gene expression, leading to longer grains and reduced chalkiness.
Both studies demonstrated that other gene variants known to improve yield or other traits affecting quality could be combined with the high quality LOC_ Os07g41200 variant to produce new elite varieties of rice.