A Novel Variation in the () Gene Promoter Improves Grain Number and Yield in Rice.

Secondary branch number per panicle plays a crucial role in regulating grain number and yield in rice. Here, we report the positional cloning and functional characterization for (), a quantitative trait locus affecting secondary branch per panicle and grain number. Our research revealed that the causative variants of are located in the distal promoter region of (), a gene previously associated with the repression of axillary meristem development in rice spikelets. is a novel allele of that causes an ∼56% decrease in its transcriptional level, leading to increased secondary branch and grain number, and reduced grain length. Field evaluations showed that increased grain yield by 10.9% in a variety, TN13, likely due to its positive effect on sink capacity. Our findings suggest that incorporation of can increase yield potential and improve the breeding of elite rice varieties.