Maize Genomics and Genetics 2025, Vol.16, No.3, 129-138 http://cropscipublisher.com/index.php/mgg 129 Research Insight Open Access The Impact of High Temperature Stress on Maize Reproductive Development and the Regulation Mechanism of Heat Tolerance Zhonggang Li 1,MinliXu2 1 Tropical Specialty Crops Research Center, Hainan Institute of Tropical Agricultural Resouces, Sanya, 572025, Hainan, China 2 Hainan Provincial Key Laboratory of Crop Molecular Breeding, Sanya, 572025, Hainan, China Corresponding author: minli.xu@hitar.org Maize Genomics and Genetics, 2025, Vol.16, No.3 doi: 10.5376/mgg.2025.16.0013 Received: 07 Apr., 2025 Accepted: 18 May, 2025 Published: 10 Jun, 2025 Copyright © 2025 Li and Xu, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Li Z.G., and Xu M.L., 2025, The impact of high temperature stress on maize reproductive development and the regulation mechanism of heat tolerance, Maize Genomics and Genetics, 16(3): 129-138 (doi: 10.5376/mgg.2025.16.0013) Abstract Maize (Zeamays L.) is particularly vulnerable to heat stress during its reproductive stage, making its yield closely tied to weather conditions—an issue that's becoming more pressing as global temperatures continue to rise. This study looks at how heat stress negatively impacts both male and female reproductive parts of maize. For instance, pollen loses its viability, anthers may fail to open properly, filaments emerge late, and ovule development can be interrupted, all of which disrupt the pollination and fertilization processes. These reproductive issues are not just surface-level—they reflect deeper physiological and molecular changes. Heat stress can upset hormone balance, increase oxidative stress, and alter how certain genes behave. One clear outcome is a drop in the number of kernels formed and overall grain yield. Timing also plays a key role; when and how long the plant is exposed to high temperatures can make a big difference. This study brings together recent findings on heat-responsive genes, key QTLs, and regulatory networks. It highlights the involvement of heat shock proteins (HSPs), systems that manage reactive oxygen species (ROS), transcription factors, and non-coding RNAs in helping maize cope with high temperatures. Real-world examples also show that it's possible to breed maize varieties that are more heat-tolerant. Finally, this study suggests that combining these insights with omics tools could lead to better strategies for future crop improvement. It underlines the need to accelerate breeding programs that are prepared for climate challenges and offers a solid foundation for future work on heat tolerance in maize. Keywords High temperature stress; Maize reproductive development; Heat tolerance mechanisms; Seed setting rate; Molecular breeding 1 Introduction Maize (Zea mays L.) is an important food crop in the world and one of the main sources of food, feed and industrial raw materials. About one-third of the world's population relies on maize as their main food. Its reproductive development process plays a decisive role in the formation of crop yield because it is directly related to the formation and development of grains. The key processes in the reproductive stage, including flowering, silking and filling, are highly sensitive to environmental stress, among which high temperature stress has a particularly significant impact on maize production (Lizaso et al., 2018; Tiwari and Yadav, 2019). Temperature has a certain effect on the differentiation and development of male and female ears. Excessive temperature will inhibit the differentiation of ears. In this process, successful fertilization and grain formation are affected by physiological characteristics such as pollen vitality, stigma receptivity and fruiting rate. High temperature stress can lead to pollen sterility, decreased fruiting rate and grain abortion, resulting in a significant reduction in maize yield (Raviteja et al., 2024). Among them, the anthesis-silking interval (ASI) and the duration of pollen shedding are the key phenotypic characteristics that affect reproductive success under high temperature stress. High temperature stress promotes the shedding of stamens and pollen, prolongs the silk interval, and reduces the number and vitality of pollen shedding, but has no significant effect on the silking time, which affects the fertilization and fruiting of corn (Alam et al., 2017). High temperature stress is one of the main limiting factors in corn production, and the intensification of climate change and global warming has further exacerbated this problem. High temperature stress significantly affects the key growth stages of corn. The yield loss caused by high temperature stress in each growth stage is as follows:
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