Summary: Tiller number per plant—a cardinal component of ideal plant architecture—affects grain yield potential. Thus, alleles positively affecting tillering must be mined to promote genetic improvement. Here, we report a Tiller Number 1 (TN1) protein harbouring a bromo‐adjacent homology domain and RNA recognition motifs, identified through genome‐wide association study of tiller numbers. Natural variation in TN1 affects its interaction with TIF1 (TN1 interaction factor 1) to affect DWARF14 expression and negatively regulate tiller number in rice. Further analysis of variations in TN1 among indica genotypes according to geographical distribution revealed that low‐tillering varieties with TN1‐hap^L are concentrated in Southeast Asia and East Asia, whereas high‐tillering varieties with TN1‐hap^H are concentrated in South Asia. Taken together, these results indicate that TN1 is a tillering regulatory factor whose alleles present apparent preferential utilization across geographical regions. Our findings advance the molecular understanding of tiller development.

Black spot disease, caused by Alternaria alternata, results in enormous losses in broccoli production. The current measures to prevent black spot disease mainly rely on seed disinfection and chemical control, but excellent disease-resistance resources are relatively scarce. In this study, we screened primers for black spot disease identification and conducted black spot disease resistance identification of 173 lines, including 70 hybrid lines and 103 inbred lines. Based on the phenotype, we have set five grades to present different symptoms of illness: high disease resistance, disease resistance, disease tolerance, susceptibility, and high susceptibility (the disease resistance gradually weakens). According to our phenotypic evaluations, 3, 55, 65, 45, and 5 lines were classified into high disease resistance, disease resistance, disease tolerance, susceptible, and high susceptibility, respectively. By comparing the proportion of resistant lines between hybrid and inbred lines, we noticed that the frequency of hybrid varieties with high disease resistance and disease resistance (28.57%) was lower than that in inbred lines (36.89%), indicating that the resistance resources have not yet been effectively utilized in hybrid broccoli breeding. Therefore, our results identified the resistance resources to black spot disease in broccoli, which lays the foundation for the exploration of disease resistance genes as well as the analysis of disease resistance mechanisms in the future.

Rice (Oryza sativa L.) leaf rolling enhances canopy architecture and photosynthetic efficiency, thereby improving yield potential. Through genome-wide association studies (GWAS) of 802 Xian and Geng rice accessions, we identified 32 loci associated with the leaf rolling index (LRI) and characterized OUTWARD ROLLED LEAF 4 (ORL4) as a regulatory gene from natural germplasm. CRISPR/Cas9-mediated knockout of ORL4 resulted in abaxially rolled leaves, driven by excessive bulliform cell proliferation and disrupted vascular patterning. A promoter variant (Chr04_19562737-C/T) modulates ORL4 expression by altering the binding affinity of the transcription factor RICE OUTERMOST CELL-SPECIFIC 8 (ROC8). Carriers of the ORL4C allele exhibit stronger ROC8 binding, higher ORL4 expression, and adaxially rolled or flat leaves; ORL4T carriers show the opposite phenotype. ORL4 forms a ternary complex with ROC8 and TOPLESS-RELATED PROTEIN 2(TPL2) to suppress ABAXIALLY CURLED LEAF 1(ACL1), a positive regulator of bulliform cell differentiation. Evolutionary analyses indicated that the ORL4C and ORL4T alleles originated from Oryza nivara and Oryza rufipogon, with ORL4C favored in Geng and ORL4T in Xian during domestication. Promoter editing of ORL4 in the elite cultivar “Shennong 89-366” generated lines with enhanced LRI, achieving a significant yield increase in field trials. This study elucidates the genetic and molecular basis of leaf rolling and provides a promising strategy for rice yield improvement via precise promoter editing.