International Journal of Molecular Evolution and Biodiversity, 2025, Vol.15, No.2, 84-98 http://ecoevopublisher.com/index.php/ijmeb 93 maintained higher antioxidant enzyme activity under stress and could effectively regulate the cell osmotic state, thus showing significant advantages in cell homeostasis and metabolic balance (Batool et al., 2022). In contrast, genotypes with weaker drought tolerance accumulated more reactive oxygen products such as H₂O₂ and MDA in the body, showing obvious oxidative damage characteristics, and their growth potential and physiological activity were severely inhibited (Khan et al., 2019). Figure 3 Comparative morphophysiological analysis of drought-tolerant and drought-sensitive rapeseed cultivars under drought stress (Adapted from Batool et al., 2022) These observations highlight the wide variation in the response mechanism of drought resistance traits under different environments, and further illustrate that varieties with strong adaptability should be selected according to specific ecological zones to achieve the maximum balance between yield and stress resistance. In actual field conditions, different climate zones also have a significant impact on rapeseed yield and drought resistance. Studies have shown that in temperate regions, the overall yield level of rapeseed is higher than that in tropical or arid climate zones. Under full irrigation, Hyola401 (a mid-maturing variety) achieved the highest yield. Under water-limited conditions, RGS003 had the smallest yield decrease due to its strong drought tolerance (Rahimi-Moghaddam et al., 2021). These results emphasize the importance of environment-genotype interactions, and also suggest that in actual breeding, the most suitable variety type should be selected according to the climatic characteristics of the target ecological zone to balance drought resistance and high yield potential. 8 Challenges and Future Prospects 8.1 Limitations of current breeding and biotechnological approaches There is still a gap in the understanding of the mechanism of action of the core regulatory factors of drought resistance. Taking the BnA.JAZ5 gene as an example, although it is known to be involved in the cross-regulation of the ABA and JA signaling pathways (Cao et al., 2022), the specific downstream target gene network and regulatory cascade still need to be further analyzed. The transcriptional heterogeneity of different genotypes under drought stress (Schiessl et al., 2020) has brought challenges to the development of universal molecular markers. To establish a stable and reliable drought resistance evaluation system, large-scale multi-environment experiments combined with rigorous molecular verification are required. There are obvious technical bottlenecks in the current drought-resistant breeding methods. Most studies focus on the improvement of a single trait or gene, which is difficult to cope with the multidimensional regulatory characteristics of the complex trait of drought resistance. Although relevant functional genes such as ROS
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