Maize Genomics and Genetics 2024, Vol.15, No.5, 257-269 http://cropscipublisher.com/index.php/mgg 260 3.4 Epigenomics and regulatory networks Epigenetic modifications, such as DNA methylation and histone modifications, play a critical role in gene regulation in maize. Studies have mapped DNA methylation profiles across the maize genome, revealing the dynamic nature of epigenetic regulation and its impact on gene expression and phenotypic variation (Springer et al., 2018). These insights are essential for understanding how environmental factors influence gene activity and trait development. Research into the regulatory networks controlling key traits in maize has uncovered the intricate interactions between genes, transcription factors, and epigenetic modifications. For instance, the identification of open chromatin regions has highlighted the functional parts of the maize genome that are crucial for gene expression and recombination. These regions account for a significant portion of phenotypic variation in agronomic traits, underscoring their importance in crop improvement (Rodgers-Melnick et al., 2016). Understanding these regulatory networks enables the development of targeted strategies for enhancing desirable traits in maize. 4 Applications of Genomic Research in Maize 4.1 Crop improvement and breeding Genomic research has significantly transformed maize breeding programs by introducing advanced tools and methodologies such as QTL mapping, GWAS, and genomic selection. These tools have enabled breeders to identify and select for desirable traits more efficiently, leading to the development of superior maize varieties (Hou et al., 2024). For instance, genomic selection has been shown to improve prediction accuracies for drought tolerance and other agronomic traits, thereby accelerating the breeding cycle and enhancing genetic gains (Shikha et al., 2017; Benavente and Giménez, 2021; Budhlakoti et al., 2022). Additionally, the integration of transgenic and genome editing technologies has provided more direct and precise approaches for trait improvement, further boosting the effectiveness of maize breeding programs (Simmons et al., 2021). Genomic research has led to the improvement of several key traits in maize, particularly those related to abiotic stress resistance. For example, drought tolerance has been a major focus, with significant advancements achieved through the identification of drought-responsive genes and SNPs. Studies have demonstrated the potential of genomic tools to enhance traits such as water-use efficiency, nitrogen-use efficiency, and yield under drought conditions (Farfan et al., 2015; Nepolean et al., 2018; Benavente and Giménez, 2021). Specific examples include the identification of 22 validated gene leads that improve yield and drought tolerance in field-grown maize (Simmons et al., 2021), and the use of genome-wide association studies to pinpoint quantitative trait variants associated with grain yield and other important traits under drought stress (Farfan et al., 2015). 4.2 Understanding genetic diversity Genomic research has played a crucial role in uncovering the genetic diversity of maize. By employing techniques such as genome-wide association studies and high-throughput SNP genotyping, researchers have been able to map the genetic variation present in maize populations. This has provided insights into the genetic architecture of important traits and facilitated the identification of novel alleles that contribute to trait diversity (Farfan et al., 2015; Shikha et al., 2017). The use of diverse maize inbred lines from different geographical regions has further highlighted the extent of genetic diversity and its potential for improving breeding programs (Farfan et al., 2015). The conservation of genetic diversity in maize and its wild relatives is essential for maintaining the crop's adaptability and resilience to environmental changes. Genomic research has contributed to this effort by identifying and characterizing the genetic resources available in wild maize relatives. This information is critical for developing strategies to preserve these genetic resources and for incorporating beneficial alleles into cultivated maize varieties (Farfan et al., 2015; Li et al., 2023). Additionally, understanding the genetic basis of traits in wild relatives can provide valuable insights for breeding programs aimed at enhancing stress tolerance and other desirable traits in maize (Li et al., 2023). Li et al. (2023) investigated the dynamic changes in gene expression throughout the process of modern maize breeding revealed by genomic analysis. The study found that breeding selection across different eras influenced
RkJQdWJsaXNoZXIy MjQ4ODYzNQ==