Maize Genomics and Genetics 2025, Vol.16, No.2, 98-107 http://cropscipublisher.com/index.php/mgg 98 Meta Analysis Open Access Meta-Analysis of Genetic Variability and Disease Resistance Traits in Maize Germplasm Against Northern Corn Leaf Blight Ming Li, Shusheng Liu, Congbiao You Tropical Microbial Resources Research Center, Hainan Institute of Tropical Agricultural Resources, Sanya, 572025, Hainan, China Corresponding author: congbiao.you@hitar.org Maize Genomics and Genetics, 2025, Vol.16, No.2 doi: 10.5376/mgg.2025.16.0010 Received: 22 Feb., 2025 Accepted: 08 Apr., 2025 Published: 23 Apr., 2025 Copyright © 2025 Li et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Li M., Liu S.S., and You C.B., 2025, Exploration and utilization of maize germplasm resources for enhanced breeding efficiency, Maize Genomics and Genetics, 16(2): 98-107 (doi: 10.5376/mgg.2025.16.0010) Abstract Northern corn leaf blight (NCLB), caused by the fungal pathogen Exserohilum turcicum, is a major foliar disease of maize that poses significant threats to yield across various agro-ecological regions worldwide. The rapid evolution and genetic diversity of the pathogen have diminished the durability of traditional qualitative resistance genes, such as Ht1, Ht2, Ht3, and Htn1. This study conducted a comprehensive meta-analysis of existing maize germplasm to evaluate genetic variability and disease resistance traits associated with NCLB. Key findings include the identification of stable quantitative trait loci (QTLs), the application of genome-wide association studies (GWAS), and high-density single nucleotide polymorphism (SNP) markers that contribute to both qualitative and quantitative resistance. This study also explored the influence of environmental factors on disease progression, dissected gene expression dynamics underlying resistance, and emphasized the importance of genetic background in phenotypic performance. Furthermore, emerging technologies such as CRISPR/Cas9 gene editing were discussed for their potential in developing broad-spectrum, durable disease-resistant maize varieties. These findings provide valuable insights and strategic directions for the enhancement of maize resistance breeding programs through integrated molecular approaches. Keywords Maize; Northern corn leaf blight; Ht genes; Genome-wide association study; Genetic diversity 1 Introduction Northern corn leaf spot (NCLB) is a foliar disease of maize (Zeamays) caused by the fungus Setosphaeria turcica (asexual form Exserohilum turcicum) that affects many regions of the world. Its most notable symptom is the appearance of long, gray spots on leaves that sometimes form a continuous patch, causing severe leaf damage, which in turn affects photosynthesis and ultimately reduces grain yield (Poland et al., 2011; Wang et al., 2018). NCLB is widespread, especially in parts of Asia and Europe, causing severe yield losses and placing considerable economic pressure on agriculture (Van Inghelandt et al., 2012; Rashid et al., 2020; Yang et al., 2021). Although various management methods have been tried, effective control remains a challenge (Chen et al., 2015; Ranganatha et al., 2021). A big problem facing corn breeders is that NCLB pathogens continue to evolve and overcome traditional disease resistance genes. For example, major resistance genes such as Ht1, Ht2, Ht3, and Htn1, which were once widely used, have become unstable as new pathogen virulent subspecies emerge (Welz and Geiger, 2000; Yang et al., 2021). Therefore, relying solely on these qualitative resistance genes is no longer enough, and there is an urgent need to find more durable and broad-spectrum resistance methods. In recent years, researchers have paid more attention to quantitative resistance loci (QTLs), trying to identify and combine these genes to breed corn varieties with more robust disease resistance (Chen et al., 2015; Wang et al., 2018; Zhu et al., 2022). This approach may solve the problem of disease resistance genes being easily overcome while ensuring yield and crop health. In conclusion, developing superior maize varieties resistant to NCLB is of great significance for ensuring food security and sustainable agriculture (Welz and Geiger, 2000; Hurni et al., 2015). This study reviewed the genetic variation associated with NCLB resistance in current maize germplasm, focusing on the key QTL and single nucleotide polymorphism (SNP) loci, evaluating the actual effects of different disease
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