Bioscience Evidence 2024, Vol.14, No.6, 270-280 http://bioscipublisher.com/index.php/be 271 which are regulated by nutrient use efficiency and photosynthetic efficiency (Figure 1) (Li et al., 2021). Advances in molecular breeding have significantly contributed to understanding these traits, enabling the development of high-yielding rice varieties (Nutan et al., 2020; Ma, 2024). Additionally, phytohormones such as gibberellins, cytokinins, and brassinosteroids play crucial roles in regulating plant height, grain number, and leaf erectness, which are essential for optimizing yield. Genetic manipulation of these hormone pathways has shown promise in enhancing rice yield potential. 2.2 Environmental factors impacting yield Environmental factors, including climate change, water availability, and soil fertility, significantly impact rice yield. Climate change poses a threat to rice production by altering temperature and precipitation patterns, which can lead to yield reductions (Nutan et al., 2020). For instance, yield potential in the Middle and Lower Reaches of the Yangtze River has declined due to climate change, necessitating adjustments in agronomic practices to mitigate these effects. Water stress is a major limiting factor in many rice-growing regions, and optimizing irrigation practices is crucial for maintaining high yields (Zhang et al., 2019). Additionally, environmental stresses such as drought and salinity adversely affect rice yield, highlighting the need for developing stress-tolerant varieties (Nutan et al., 2020). 2.3 Role of agronomic practices in yield optimization Agronomic practices play a vital role in optimizing rice yield by enhancing both genetic potential and environmental adaptability. Improved crop management techniques, such as site-specific nitrogen management and alternate wetting and drying irrigation, have been shown to significantly increase rice yields. For example, in the lower reaches of the Yangtze River, improved high-yielding cultivation practices resulted in a 26.8% increase in rice yield compared to local farmer practices (Li et al., 2012). Optimized management practices, including appropriate water and fertilizer management and dense planting, have also been effective in enhancing grain yield and nitrogen use efficiency in super hybrid rice (Deng et al., 2022). Furthermore, regular cultivar replacement and continuous adjustment of management practices have sustained high annual rice production in intensive cropping systems (Ladha et al., 2021). These findings underscore the importance of integrating agronomic improvements with genetic advancements to achieve sustainable rice yield gains (Li et al., 2019). Figure 1 A simplified representation of pathways controlling rice grain yield (Adopted from Li et al., 2021) Image caption: Rice grain yield is determined by grain weight, grain number per panicle, and effective tiller number, all of which are regulated by complex networks. Absorption and utilization of nutrients as well as photosynthetic efficiency are major physiological factors determining rice grain yield. MAPK, mitogen-activated protein kinase; N, nitrogen; P, phosphorus; K, potassium (Adopted from Li et al., 2021)
RkJQdWJsaXNoZXIy MjQ4ODYzMg==