Maize Genomics and Genetics 2024, Vol.15, No.1, 36-48 http://cropscipublisher.com/index.php/mgg 41 The introgression of favorable alleles from teosinte into modern maize has also been instrumental in improving yield. Studies have shown that teosinte harbors alleles that can enhance kernel composition traits, such as protein, oil, and starch content. For instance, genetic analysis of teosinte near-isogenic lines (NILs) has identified alleles that significantly increase kernel oil content, which is crucial for both nutritional value and industrial uses (Karn et al., 2017). 5.2 Stress tolerance and disease resistance One of the major challenges in agriculture is the ability to develop crops that can withstand various environmental stresses and resist diseases. Teosinte, being a wild relative, has adapted to a range of environmental conditions and exhibits a broader genetic diversity compared to cultivated maize. This diversity includes alleles that confer resistance to biotic and abiotic stresses. For example, the genetic diversity found in teosinte has been shown to include alleles for enhanced drought tolerance. The introgression of these alleles into maize has led to the development of drought-resistant maize varieties that can maintain yield under water-limited conditions. Similarly, alleles from teosinte have been used to improve maize's resistance to pests and diseases. The maize-teosinte introgression populations have shown increased resistance to common pests like the corn borer and diseases such as northern corn leaf blight (Hufford et al., 2012). Teosinte also exhibits a rich metabolic profile, including higher concentrations of secondary metabolites like phenolic compounds, which play a crucial role in plant defense mechanisms. Screening teosinte populations for phenolic content has identified specific compounds that contribute to enhanced antioxidant activity, which can be leveraged to improve the health benefits and stress tolerance of maize (Zavala-López et al., 2018). 5.3 Nutritional enhancements The nutritional quality of maize is a critical aspect of its value as a staple food crop. Teosinte, despite its smaller kernel size, contains higher protein content compared to modern maize. Studies on the genetic basis of kernel composition have shown that teosinte alleles can enhance the protein content of maize kernels, making them more nutritious. For instance, teosinte has been found to have a higher average alpha zein content, a type of storage protein, which is essential for the nutritional quality of the grain (Flint-Garcia et al., 2009). Moreover, the genetic introgression from teosinte has also been utilized to improve the oil content in maize kernels. Higher oil content not only increases the caloric value of maize but also provides essential fatty acids that are beneficial for human health. The identification of QTLs associated with high oil content in teosinte has enabled breeders to enhance this trait in maize through selective breeding programs (Karn et al., 2017) . In addition to protein and oil content, the genetic diversity of teosinte has been explored to enhance other nutritional aspects of maize. For example, teosinte has been found to possess unique metabolites with potential health benefits. The diversity in phenolic compounds and their antioxidant properties in teosinte can be utilized to develop maize varieties with improved nutritional and health-promoting properties (Figure 2) (Zavala-López et al., 2018). The comparative genomics of teosinte and maize has significantly impacted agricultural practices by enhancing yield and productivity, improving stress tolerance and disease resistance, and enhancing the nutritional quality of maize. The continued exploration and utilization of teosinte genetic resources hold promise for the future improvement of maize, ensuring its resilience and nutritional value in the face of changing environmental conditions and growing global food demand. 6 Biotechnological Applications 6.1 Genetic engineering and CRISPR technologies The application of genetic engineering and CRISPR technologies in maize has revolutionized the ability to manipulate its genome with precision. One of the most significant advancements has been the use of CRISPR/Cas9 to target specific genes associated with desirable traits. CRISPR technology allows for precise editing of the maize genome, enabling the introduction of beneficial traits from teosinte or the correction of deleterious mutations. For example, the teosinte branched1 (tb1) gene, which plays a critical role in the plant's architecture, can be modified to enhance maize's yield and adaptability (Doebley et al., 1995).
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