Maize Genomics and Genetics 2025, Vol.16, No.6, 316-324 http://cropscipublisher.com/index.php/mgg 317 This study aims to identify QTLS related to the occurrence time of filaments under high-temperature stress, thereby clarifying the genetic structure of this key trait. By combining phenotypic assessment and high-resolution genotyping under controlled high-temperature stress conditions, a QTL map related to filaments appearance and related reproductive traits is drawn. These QTLS are verified in different genetic backgrounds and environments. Provide reliable markers for breeding projects targeting heat resistance. This research is expected to promote strategic breeding of corn varieties, enabling them to better withstand rising temperatures and ensure stable yield formation in the context of climate change. 2 Genetic Regulation and Environmental Response Mechanisms of Silk Emergence 2.1 Genetic basis and major gene regulatory models for silk emergence Corn spinning is not something that can be determined by a single gene. According to current research, the regulatory mechanism involves both cis and trans elements, and the situation is not always simply linear. Transcription factors like MYB do play a key role in regulating the development, metabolism and response to environmental stress of filaments (Wang et al., 2024). However, there are also significant differences among different inbred lines. Some genes are highly expressed in one material but show mediocre performance in others. eQTL analysis has identified a large number of filament-specific expression genes, especially trans eQTL is more active in regulating these genes (McNinch et al., 2020; Chu et al., 2024). However, the time and intensity of filamentary expression are likely related to environmental conditions and the way genotypes are combined, and its dynamic changes also add a lot of difficulty to precise breeding. 2.2 Disruptive mechanisms of heat stress on flowering coordination and reproductive physiology Whether the filaments can come out on time often determines whether powder can be applied in the end. It is precisely when the temperature is high that this matter is most likely to go wrong. When the filaments are late and the pollen Withers early, the elongation of ASI naturally leads to a decline in fertilization efficiency. However, the problem is not limited to the filaments. The anthers do not crack, the pollen is inactive, and the fine structure is damaged at high temperatures. These factors are often brought down together (Wang et al., 2019). From a molecular mechanism perspective, the accumulation of ROS within filamentous cells is a major problem, as it can cause cell death and block the development of pollen tubes. Many genes related to hormones, ROS clearance and stress response pathways become unstable in expression at high temperatures (Gong et al., 2024). The time when problems are most likely to occur is not before the flowering period, but at the moment when silk production just begins and pollination is underway (Begcy et al., 2019). 2.3 Role of hormones (e.g., GA, ABA) and ROS signaling in silk emergence response When it comes to filaments and high temperatures, it is impossible to avoid plant hormones, especially GA and ABA. GA is the "engine" that drives cell elongation and pulls filaments to grow out. ABA is more like a "brake" or "regulator", and it has regulatory effects on both flowering rhythm and stress response (Waadt et al., 2022; Shah et al., 2023). However, the relationship between the two is not always opposing. Under some conditions, the delicate balance between them is the key to the smooth appearance of filaments. In addition, high-temperature stress often induces a large accumulation of ROS. Although ROS itself is a signaling molecule, once it is excessive, it is easy to cause harm. ROS and hormone signals can "crosstalk" and jointly affect gene expression and cell state (Xia et al., 2015). So, whether silk spinning can be successfully completed is not merely a matter of genes; the regulatory network behind it is much more complex. 3 Key Agronomic Factors Influencing Silk Emergence Under Heat Stress 3.1 Correlation analysis between plant height and silk elongation Under the background of high-temperature stress, the reduction of plant height is actually not uncommon, and in research, it is often accompanied by the phenomenon of delayed filaments. But whether there is always a direct connection between the two actually depends on the specific situation. For instance, the differences in expression among different genotypes are quite obvious: in some varieties, the plant height has significantly decreased, but the spikelets have not been much affected and can still extend normally. That is to say, these genotypes may have some kind of "compensation mechanism" that enables them to maintain a certain reproductive capacity even when
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