Field Crop 2024, Vol.7, No.1, 27-36 http://cropscipublisher.com/index.php/fc 30 plant's ability to acclimate to chilling stress by altering regulatory networks and inducing genes with protective functions indicates a genetic mechanism for improved stress tolerance (Zeng et al., 2014). The genomic analyses of a wild ancestor and a domesticated variety of cassava have revealed positive selection for genes involved in photosynthesis and starch accumulation (Figure 2), as well as negative selection for genes involved in cell wall biosynthesis and secondary metabolism, including cyanogenic glucoside formation (Wang et al., 2014). These findings suggest that cassava has genetically adapted to optimize energy production and reduce potentially harmful compounds in response to environmental pressures. Figure 2 High efficiency starch accumulation model for cassava (Wang et al., 2014) Note: The red arrow indicates the direction and intensity of carbon flux in cultivated varieties, indicating the biological processes in which carbon flux increases in cultivated varieties, such as starch synthesis; Blue arrow: indicates the carbon flux in wild varieties, which is usually weak and reflects the natural state of biological pathways in the wild environment 2.3 Genetic connections between wild and cultivated cassava ancestor species The genetic resources of wild cassava ancestral species provide valuable insights into the domestication and adaptation processes of crops. Wild ancestral species may have some unique genetic characteristics, such as stress resistance, adaptability, etc., which are of great significance for the cultivation and improvement of cassava. The genetic exchange between cultivated and wild ancestral species is an important source of genetic diversity and adaptive evolution in cassava. Through breeding methods such as hybridization and backcrossing, scientists can introduce the excellent characteristics of wild ancestral species into cultivated varieties, thereby improving the yield, quality, and stress resistance of cassava. Comparative genomic studies have identified gene models unique to wild and domesticated varieties, with millions of single nucleotide variations and high levels of heterozygosity. Wang et al. (2014) provided detailed information on single nucleotide variations (SNVs) and insertions/deletions (InDels) of cassava varieties W14, KU50, and CAS36 compared to the reference genome AM560 (Figure 3). These genetic differences are formed by natural selection and domestication, affecting traits such as starch accumulation and stress response. The genetic exchange between cultivated and wild ancestor species is evident in the unique gene model and selected genes in
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