Kernel row number (KRN) is a pivotal determinant for yield in maize breeding programs. However, the genetic basis underlying KRN remains largely elusive. To identify candidate genes regulating KRN, a population of 318 BC₄F₄ chromosomal segment substitution lines (CSSLs) was developed via backcrossing, with Baimaya (BMY) as the donor parent and B73 as the recurrent parent. Furthermore, a high-density genetic linkage map containing 2859 high-quality single-nucleotide polymorphism (SNP) markers was constructed for quantitative trait locus (QTL) mapping of KRN. Notably, 19 QTLs controlling KRN were detected across three environments and in the Best Linear Unbiased Prediction (BLUP) values; among these, a major-effect QTL (qKRN4.09-1) was consistently identified across all three environments and BLUP. Then, the integration of linkage mapping and transcriptome analysis of 5 mm immature ears from near-isogenic lines (NILs) uncovered a candidate gene, Zm00001eb205550. This gene exhibited significant downregulation in qKRN4.09-1^BMY, and two missense variants were detected between qKRN4.09-1^BMY and qKRN4.09-1^B73. Zm00001eb205550 exhibited preferential expression in developing ears. Moreover, the pyramiding of favorable alleles from the five stable QTLs significantly increased KRN in maize. These findings advance our genetic understanding of maize ear development and provide valuable genetic targets for improving KRN in maize breeding.

The NSUN family is essential for RNA 5-methylcytosine modification (m5C) in eukar-yotes. However, no NSUN genes have been identified in maize, and the characteristics of ZmNSUN genes remain unexplored. Here, we performed a comprehensive in-vestigation of NSUN genes across seven Poaceae species. Our analysis identified a total of 63 Poaceae NSUN genes, including eight ZmNSUN genes in maize. Phylogenetic and feature analyses classified the Poaceae NSUNs into six subgroups (SGs), suggest-ing that the divergence of these SGs may have occurred prior to the divergence between plants and animals. Expression profiling indicated that ZmNSUN genes are generally repressed by heat stress. Co-expression network analysis suggested potential roles of ZmNSUN genes in maize development, and expression quantitative trait locus (eQTL) analysis results demonstrated that expression levels of multiple ZmNSUN genes are significantly associated with maize agronomic traits. Collectively, these findings provide novel insights into the evolutionary dynamics of the NSUN family and highlight specific ZmNSUN genes as promising candidates for molecular breeding to improve maize yield and stress adaptability.

Trichome birefringence-like proteins function as polysaccharide O-acetyltransferases that catalyze the O-acetylation of cell wall polysaccharides and play widespread roles in regulating plant growth and stress responses. However, no TBL genes have been functionally characterized in maize, and their biological properties remain largely unexplored. Through bioinformatic analysis, we identified 74 maize TBL genes (designated ZmTBL1–ZmTBL74) among the maize genome. Comprehensive analyses of their phylogenetic relationships, basic physicochemical and sequence characteristics, putative upstream regulatory transcription factors and expression patterns were conducted. Expression profiling and qPCR analyses revealed that ZmTBLs respond widely to abiotic stresses, including heat and cold. Association analyses demonstrated that sequence variations in ZmTBL57 and ZmTBL69 correlate with maize agronomic traits. These findings elucidate the molecular characteristics and evolutionary history of maize TBL genes and underscore their roles in abiotic stress responses. In summary, the foundation established by this work will facilitate further functional characterization of TBL genes in maize.

Ear length (EL) is a critical determinant of yield in maize breeding, yet its genetic underpinnings remain poorly characterized. This study aimed to identi