Rice Genomics and Genetics 2025, Vol.16, No.2, 71-85 http://cropscipublisher.com/index.php/rgg 71 Feature Review Open Access Optimizing Planting Density to Enhance Rice Productivity Xiaoying Zhu1,2 1 Deqing Xinshi Changlin Family Farm, Deqing, 313201, Zhejiang, China 2 Zhejiang Agronomist College, Hangzhou, 310021, Zhejiang, China Corresponding email: 181833674@qq.com Rice Genomics and Genetics, 2025, Vol.16, No.2 doi: 10.5376/rgg.2025.16.0007 Received: 20 Jan., 2025 Accepted: 28 Feb., 2025 Published: 10 Mar., 2025 Copyright © 2025 Zhu, 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: Zhu X.Y., 2025, Optimizing planting density to enhance rice productivity, Rice Genomics and Genetics, 16(2): 71-85 (doi: 10.5376/rgg.2025.16.0007) Abstract Improving rice yield is of great significance to food security. Under limited arable land conditions, improving yield per unit area by optimizing cultivation measures is a key strategy. Planting density is an important factor affecting rice population growth, yield formation and resource utilization efficiency. This study systematically analyzes the theoretical basis and mechanism of optimizing planting density to improve rice productivity, including the impact on plant growth and development, yield composition, rice quality and economic benefits, and discusses it in combination with practical cases in Nanchang, Jiangxi and Leshan, Sichuan. Studies have shown that a reasonable increase in planting density can increase the number of effective panicles and the number of panicles per unit area, thereby significantly increasing rice yield, but too high density will lead to intensified individual competition, a decrease in the number of panicles, a decrease in the fruiting rate, and an increase in the risk of lodging and disease, which will ultimately be counterproductive. The optimal density varies under different ecological regions and cultivation methods, and should be optimized according to local conditions such as variety characteristics, nitrogen fertilizer management and climatic conditions. The Nanchang Plain double-season rice area has achieved good results by appropriately reducing the sowing density to enhance individual lodging resistance, while the Leshan hilly area has achieved group yield increase through close planting combined with machine transplanting. In general, optimizing planting density requires balancing the relationship between group and individual, source of production and source of storage, to achieve high yield and high efficiency and stable yield and increase income. The comprehensive analysis of this article can provide a scientific basis for high-yield rice cultivation. Keywords Rice; Planting density; Group growth; Yield composition; Economic benefits; Regional practice 1 Introduction Rice is the staple food crop for nearly half of the world's population, and improving rice productivity is crucial to ensuring food security. Against the backdrop of limited arable land resources and intensified climate change challenges, how to achieve continuous improvement in rice yield per unit area by optimizing agronomic measures has become a research hotspot and a practical need (Guo et al., 2024). As an important parameter of rice cultivation, planting density (planting density) directly affects population structure and individual development, and plays a key role in the final yield formation. Traditional cultivation often relies on experience to determine density, but there are differences in the optimal density under different varieties and habitat conditions; too sparse planting leads to the failure to fully utilize the production potential of the population, while too dense planting causes individual competition and the risk of lodging and yield reduction. In recent years, with the development of super rice breeding and mechanized cultivation, the theory of achieving high yield through "moderate dense planting" has been proposed. For example, hybrid rice breeding experts in China pointed out that high-yield cultivation not only depends on the genetic potential of the variety, but also requires the coordination of reasonable basic seedlings and population structure (Jiang et al., 2025). Studies have shown that increasing the basic seedling density in combination with single-plant planting is expected to make full use of space resources, promote the construction of large rice populations, and achieve increased yields (Tian et al., 2022). At the same time, the emphasis on density optimization under different ecological conditions is different. For example, double-season rice areas often face the problems of high temperature and high humidity, and plants are prone to excessive growth and lodging. It is necessary to control the basic seedlings to improve the stable yield of the group, while dryland cultivation or direct seeding cultivation often requires increasing the sowing amount to
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