Genomics and Applied Biology 2024, Vol.15, No.1, 12-21 http://bioscipublisher.com/index.php/gab 19 genes, has additive effects and is affected by the environment. The aim of this study was to identify genomic regions, including putative genes, associated with gray leaf spot resistance under natural conditions of disease occurrence. On phenotypic data consisting of 157 tropical maize inbred lines evaluated in Maringa, Brazil, 355 Genome-wide association studies were performed on 972 single nucleotide polymorphism markers. Seven single nucleotide polymorphisms were significantly associated with gray leaf spot, some of which were located in previously reported quantitative trait locus regions. Three gene models associated with relevant single nucleotide polymorphisms expressed in tissues associated with flowering time and gray leaf spot infection explained a substantial proportion of the phenotypic variation, ranging from 0.34 to 0.38. Gene model GRMZM2G073465 (bin 10.07) encodes caspase 3 protein, gene model GRMZM2G007188 (bin 1.02) expresses ribosylation factor-like protein, and gene model GRMZM2G476902 (bin 4.08) encodes armadillo repeat protein. These three proteins are associated with plant defense pathways. Once these genes are verified in subsequent studies, they will contribute to marker-assisted selection (MAS) and help improve understanding of resistance to gray leaf spot in maize (Kuki et al., 2018) (Figure 3). Figure 3 Marker-trait association analysis of the percentage of leaf area infected by gray leaf spot (Kuki et al., 2018) The successful application of MAS is not only reflected in corn disease resistance breeding, but also extends to the improvement of other important agronomic traits. For example, GWAS has also made significant progress in the fields of corn drought resistance, salt tolerance, and nutritional quality improvement. By precisely utilizing molecular markers identified by GWAS, MAS has become an indispensable technology in modern corn breeding. It is worth noting that although MAS greatly improves the efficiency of breeding, its successful implementation relies on accurate molecular markers and in-depth genetic background knowledge. Therefore, future research needs to further explore more disease resistance genes and markers and verify the effects of these markers under different genetic backgrounds and environmental conditions to ensure the widespread application and effectiveness of MAS in corn disease resistance breeding. 3.3 Future directions and challenges Genome-wide association studies (GWAS) in corn disease resistance breeding is gradually moving from theoretical research to practical application, providing strong scientific support for corn breeding. Disease resistance genes and genetic markers identified through GWAS have begun to be used to guide corn disease resistance breeding projects, accelerating the breeding and promotion of highly disease-resistant corn varieties. In the future, the application of GWAS in corn disease resistance breeding is expected to be further expanded, especially when combined with next-generation high-throughput sequencing technology and gene editing technology (such as CRISPR-Cas9), the application potential of GWAS will be greatly expanded. On the one hand,
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