Maize Genomics and Genetics 2024, Vol.15, No.4, 171-181 http://cropscipublisher.com/index.php/mgg 173 maize, exhibits a significantly different phenotype compared to modern maize, despite their genetic similarities (Zobrist et al., 2021). Initial genetic studies revealed that a small number of major loci could explain a large portion of the phenotypic changes observed during maize domestication (Liu et al., 2019). These findings supported the hypothesis that selective breeding and domestication led to the remarkable transformation of teosinte into modern maize. 3.2 Archeological evidence Archeological evidence has played a crucial role in understanding the domestication process of maize from teosinte. Fossil records and ancient maize cobs found in archeological sites provide insights into the early stages of maize domestication. These records indicate that teosinte was first domesticated around 10 000 years ago in the Balsas River Valley of southern Mexico (Adhikari et al., 2021). The archeological findings suggest that early agricultural communities selectively bred teosinte for desirable traits, leading to the gradual transformation into maize. This evidence underscores the importance of teosinte as a genetic reservoir that contributed to the development of modern maize varieties. 3.3 Molecular evidence Molecular studies have further elucidated the genetic relationship between teosinte and maize. Advances in genomic technologies have allowed researchers to identify specific genes and quantitative trait loci (QTLs) that differentiate teosinte from maize. For instance, single-molecule long-read sequencing has revealed extensive genomic and transcriptomic variation between maize and its wild relative teosinte (Li et al., 2021). This study identified 70 044 nonredundant transcript isoforms and constructed a draft genome of teosinte, providing a valuable resource for maize breeding programs. Additionally, molecular evidence has shown that teosinte harbors unique alleles that can enhance modern maize varieties. For example, the UPA2 allele, which reduces leaf angle and improves high-density maize yields, originated from teosinte but was lost during domestication. Introgressing such wild alleles into modern maize hybrids can enhance agronomic traits and yield potentia (Tian et al., 2019). Overall, the integration of archeological and molecular evidence has significantly advanced our understanding of the teosinte-maize relationship, highlighting the potential of teosinte as a valuable genetic resource for maize improvement. 4 Genetic Contributions of Teosinte to Maize 4.1 Genetic loci associated with domestication Teosinte, the wild ancestor of maize, has played a crucial role in the domestication and genetic enhancement of maize. The genetic architecture of teosinte and maize has been extensively studied to understand the loci associated with domestication. One significant locus is the teosinte branched1 (tb1) gene, which has been shown to have large effects on plant architecture and ear morphology. The tb1 gene is involved in the plant's response to environmental conditions, influencing the development of long or short branches, which was a key factor in maize domestication (Figure 2) (Studer et al., 2012). Additionally, other loci such as UPA1 and UPA2, which regulate plant architecture, have been identified. These loci contribute to the upright plant architecture that facilitates dense planting, a trait beneficial for modern agriculture (Tian et al., 2019). 4.2 Traits inherited from teosinte Several important traits have been inherited from teosinte, contributing to the genetic diversity and adaptability of modern maize. For instance, teosinte harbors stronger alleles for kernel composition traits, including starch, protein, and oil content, which can be exploited for the improvement of these traits in maize (Karn et al., 2017). Another inherited trait is the narrow plant architecture conferred by the UPA2 allele, which enhances high-density maize yield (Figure 3) (Tian et al., 2019). Furthermore, teosinte has contributed to the morphological diversification of maize, with traits such as ear structure and shattering being influenced by genes like ramosa1 (ra1) and zagl1 (Weber et al., 2008). These traits have been crucial in the adaptation and improvement of maize for various agricultural practices..
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