Maize Genomics and Genetics 2024, Vol.15, No.3, 136-146 http://cropscipublisher.com/index.php/mgg 142 Improvement Center (CIMMYT) has developed elite tropical maize germplasm with tolerance to key abiotic and biotic stresses, which has been deployed across sub-Saharan Africa, Asia, and Latin America (Prasanna et al., 2021). Crop rotation diversification has also been shown to increase maize yields and resilience to adverse growing conditions, further highlighting the importance of genetic diversity in building climate-resilient agricultural systems (Bowles et al., 2020). The integration of advanced genomic tools and breeding strategies continues to enhance the climate resilience of maize, ensuring stable production in the face of changing environmental conditions (Gedil and Menkir, 2019; Bailey-Serres et al., 2019). 6 Challenges and Future Directions 6.1 Barriers to germplasm utilization One of the primary challenges in utilizing genetic diversity for maize improvement is the limited genetic diversity within elite germplasm pools. This limitation restricts the potential for breeding new varieties that can address emerging agricultural challenges such as climate change and evolving pest pressures (Gorjanc et al., 2016; Allier et al., 2019). Additionally, the integration of diverse germplasm into breeding programs is often hampered by logistical constraints, including the management of large-scale pre-breeding programs and the accurate phenotyping of diverse genetic materials (Gorjanc et al., 2016). The complexity of polygenic traits further complicates the effective utilization of landrace diversity, necessitating advanced strategies for targeted trait improvement (Rogers et al., 2022). 6.2 Advances in genomic tools and techniques Recent advancements in genomic tools and techniques have significantly enhanced the potential for maize improvement. Genomic selection (GS) and genome-wide association studies (GWAS) have been pivotal in identifying beneficial alleles and haplotypes for complex traits (Rogers et al., 2022). The integration of doubled haploid production, genomic selection, and genome optimization represents a new model for maize breeding, facilitating the rapid incorporation of superior alleles into breeding programs (Hufford et al., 2012). These tools enable the precise mapping of trait-associated loci and the development of predictive models that can accelerate genetic gain (Hufford et al., 2012; Rogers et al., 2022). 6.3 Integrating traditional and modern breeding The integration of traditional breeding methods with modern genomic tools is essential for maximizing genetic gain in maize improvement programs. Traditional methods, such as phenotypic selection and the use of heterotic groups, remain valuable for their proven effectiveness in hybrid performance (Yu et al., 2020). However, combining these methods with genomic tools, such as marker-assisted selection and genomic prediction, can enhance the efficiency and accuracy of breeding programs (Hufford et al., 2012; Gedil and Menkir, 2019). This integrated approach allows for the systematic incorporation of diverse genetic resources, including landraces and wild relatives, into elite breeding pools (Warburton et al., 2008; Allier et al., 2019). 6.4 Policy and regulatory frameworks Effective policy and regulatory frameworks are crucial for facilitating the utilization of genetic diversity in maize breeding. Policies that support the conservation and sharing of genetic resources, such as the establishment of collaborative diversity panels, are essential for broadening the genetic base of elite germplasm (Allier et al., 2019). Additionally, regulatory frameworks that promote the adoption of advanced genomic tools and techniques can accelerate the development and dissemination of improved maize varieties (Gedil and Menkir, 2019). Ensuring that these policies are aligned with international standards and agreements will enhance global collaboration and resource sharing (Warburton et al., 2008). 6.5 International collaboration and funding International collaboration and funding are vital for the success of maize improvement programs. Collaborative projects that bring together public and private sector breeders, such as the Germplasm Enhancement of Maize (GEM) project, have demonstrated the potential for significant genetic gain through the sharing of resources and expertise (Rogers et al., 2022). Funding from international organizations and governments can support the development of innovative breeding strategies and the implementation of advanced genomic tools (Gedil and
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