Rice Genomics and Genetics 2024, Vol.15, No.4, 153-163 http://cropscipublisher.com/index.php/rgg 154 This study comprehensively reveals the key yield related genes of rice and their roles in molecular breeding, summarizes the current understanding of the genetic and molecular mechanisms of yield related traits in rice, focuses on the latest progress of molecular breeding technology and its application in rice yield increase, and discusses the potential challenges and future directions in the field of rice molecular breeding. Molecular breeding provides a promising approach for achieving a significant increase in rice yield. By utilizing knowledge of key yield related genes and advanced breeding techniques, we hope to develop high-yield rice varieties that can meet future food needs and contribute to global food security, making significant contributions to global food security. 1 Key Yield-Related Genes in Rice 1.1 Grain number and size genes In the field of molecular breeding, the increase in rice yield is often closely related to the discovery and utilization of key yield related genes. These genes regulate the growth and development process of rice, thereby affecting its yield. The Gn1a gene is closely related to the number of grains in rice. Through research, it has been found that the protein encoded by Gn1a plays an important role in the development of rice meristem, affecting panicle branching and spikelet number. The mutation of Gn1a leads to higher grain count and significantly contributes to the heavy panicle phenotype of hybrid rice (Li et al., 2016; Wang et al., 2018). The GS3 gene is a key gene that controls rice grain type and weight. Research has shown that GS3 encodes a transmembrane protein, and its domain variation significantly affects the grain length, width, and weight of rice. GS3 is a major quantitative trait locus (QTL) for grain length and weight. The mutation of GS3 leads to larger grain size and weight, making it a key gene in improving grain size in rice breeding programs (Li et al., 2016; Wang et al., 2018; Mao et al., 2021). 1.2 Panicle architecture genes The DEP1 gene is an important gene that affects the structure of rice panicles. Mutations in this gene can lead to changes in the structure of rice panicles, such as an increase in grain number and a reduction in panicle length. These changes help to increase the yield of rice. DEP1 affects the structure of panicles by enhancing meristem activity, making them dense and upright with an increase in grain number. This gene is widely used in high-yield rice varieties(Huang et al.,2009; Li et al., 2016; Mao et al., 2021). In molecular breeding, rice varieties with excellent panicle structure can be cultivated by utilizing mutants of the APO1 gene, thereby achieving an increase in yield. APO1 and APO2 regulate spike size and grain number by regulating meristem activity. The LARGE2-APO1/APO2 regulatory module is crucial for controlling these traits, making it a promising target for improving rice yield (Figure 1) (Huang et al., 2021). Huang et al. (2021) revealed a genetic interaction between the LARGE2 gene and the panicle structure genes APO1 and APO2, which affect the size of rice panicles. Through mutations in the APO1 gene (APO1 cri) and LARGE2 gene (large2-3) (Figure 1), significant changes were observed in the primary and secondary branches of rice panicles, as well as the number of grains per panicle. This indicates a genetic interaction between LARGE2 and APO1, which jointly regulate spike development. This discovery is of great significance for understanding the molecular mechanism of rice yield formation and future genetic improvement. 1.3 Grain weight and quality genes GW2 is a key gene that determines the grain weight of rice, and its regulation has a significant impact on rice yield. The protein encoded by the GW2 gene plays an important role in cell division and growth. By regulating the expression of this gene, it can effectively change the grain weight of rice. The role of this gene in grain weight makes it a key goal of breeding programs aimed at improving rice yield (Singh et al., 2022). The Wx gene is related to the quality of rice, especially the content of amylose. Although the Wx gene is mainly related to the starch quality and glutinosity of rice, it also indirectly affects the yield of rice. The protein encoded by the Wx gene is a key enzyme in the starch synthesis process, and its mutation can cause changes in the starch
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