Wheat (Triticum aestivum L.) is a major cereal crop grown worldwide, providing approximately 20% calorie and 25% protein intake. Wheat productivity is significantly affected by high temperatures, particularly during the grain-filling period. Heat stress accelerates leaf senescence, impairs photosynthesis, reduces starch accumulation, and alters protein synthesis, ultimately leading to a decrease in grain yield and quality. To mitigate the adverse effects of heat stress, wheat utilizes adaptation mechanisms, including the expression of heat shock proteins, activation of antioxidant defense systems, osmotic regulation, and transcription factor-mediated gene regulation. Stay-green traits also play a role in maintaining photosynthetic efficiency at high temperatures. Breeding strategies such as traditional breeding, marker-assisted selection , genomic selection , and genome editing are being explored to improve heat tolerance. Recent advances in the CRISPR-Cas9 technology enable precise gene editing, thereby enhancing the resilience of wheat to heat stress. Additionally, quantitative trait locus mapping and genome-wide association studies facilitated the identification of genetic regions associated with heat tolerance, thereby accelerating the development of climate-resilient wheat varieties. Future research should focus on integrating genetic and molecular approaches with sustainable agronomic practices and crop modeling strategies to optimize wheat productivity under rising temperatures. The integration of advanced breeding techniques and improved crop management can facilitate the development of wheat varieties that are more resilient to climate change.

Powdery mildew (Blumeria graminis f. sp. tritici) significantly affects wheat yield and flour quality. Plant resistance to powdery mildew has been investigated for decades, and numerous resistance genes and quantitative trait loci (QTLs) for molecular markers have been discovered. In Korea, powdery mildew occurs initially in spring, due to frequent rain and low temperatures, becoming severe during the harvest season. In Korea, systematic monitoring and quantitative and qualitative impact assessments of powdery mildew outbreaks have never been conducted properly. Herein, the lifecycle of powdery mildew, resistance genes, QTLs, and selection markers in wheat were examined to elucidate powdery mildew resistance, develop resistant varieties, and genetic markers suitable for the domestic environment.

As recent advances in gene editing technologies have enabled rapid and accurate modification of target genes, new varieties are being developed through the application of gene editing technologies in various crop species. In particular, the CRISPR/Cas9 system has become a tool of choice for gene editing because it is much more economical and efficient than previous tools such as ZFN and TALEN, and is being actively used to improve various breeding traits, including biotic and abiotic stress tolerance to overcome the limitations of conventional plant breeding technologies. In this review, we retrieved 210 papers describing the utilization of CRISPR/Cas9 in rice published between 2013 and 2021 and classified them according to the field of study and traits of interest. Further case studies were conducted on 21 and 12 research papers that reported the enhancement of biotic and abiotic stress tolerance, respectively. This demonstrated that CRISPR/Cas9-based gene editing can be highly effective in improving resistance to bacterial (bacterial leaf blight and bacterial leaf streak), fungal (blast, sheath blight), and viral (rice tungro spherical virus, rice black streak virus) diseases as well as various abiotic stresses, including drought, salinity, cold, and heat, in many cases, without diminishing important agronomic traits. As recent technological advances have begun to overcome the major limitations of CRISPR/Cas9 gene editing, such as low HDR efficiency and off-target effects, it is expected that more research on gene function and cultivar development will adopt CRISPR/Cas9 as a major gene editing tool in the future. To effectively apply such innovative technologies in crop improvement, much effort is required to establish more reasonable and detailed policies for regulating crops developed through new breeding technologies.