Rice Genomics and Genetics 2024, Vol.15, No.6, 277-286 http://cropscipublisher.com/index.php/rgg 277 Feature Review Open Access Adaptation Advancements in Hybrid Rice Varieties: Integrating Intersubspecific Heterosis and High-Yield Traits Xinguang Cai, Qiangsheng Qian Modern Agricultural Research Center, Cuixi Academy of Biotechnology, Zhuji, 311800, Zhejiang, China Corresponding email: qiangsheng.qian@cuixi.org Rice Genomics and Genetics, 2024, Vol.15, No.6 doi: 10.5376/rgg.2024.15.0027 Received: 27 Oct., 2024 Accepted: 26 Nov., 2024 Published: 03 Dec., 2024 Copyright © 2024 Cai and Qian, This is an open access article published under the terms of the creative commons attribution licensse, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Cai X.G., and Qian Q.S., 2024, Adaptation advancements in hybrid rice varieties: integrating intersubspecific heterosis and high-yield traits, Rice Genomics and Genetics, 15(6): 277-286 (doi: 10.5376/rgg.2024.15.0027) Abstract The development of hybrid rice varieties has significantly contributed to global food security by enhancing yield and quality traits. Recent advancements in hybrid rice breeding have focused on integrating intersubspecific heterosis and high-yield traits through rational design and genomic approaches. Studies have demonstrated that the exploitation of wide-cross compatibility and the identification of heterosis-associated genes, such as qSS7 and qHD8, are crucial for achieving high yield in hybrid rice varieties. Additionally, the integration of genomic, phenomic, and transcriptomic analyses has uncovered multiple quantitative trait loci (QTLs) that cumulatively drive yield heterosis, highlighting the importance of superior alleles and their dominance effects. Despite the progress, challenges such as poor grain-filling and low seed-setting rates in super hybrid rice remain, necessitating further research to optimize these traits. This study proved that the recent advancements in hybrid rice breeding, emphasizing the integration of intersubspecific heterosis and high-yield traits to develop superior hybrid rice varieties. Keywords Hybrid rice; Intersubspecific heterosis; High-yield traits; Genomic analysis; Quantitative trait loci (QTLs) 1 Introduction The quest for increasing rice yield has been a pivotal focus in agricultural research, driven by the need to ensure global food security amidst a growing population and diminishing arable land. Hybrid rice, which leverages the phenomenon of heterosis or hybrid vigor, has emerged as a significant breakthrough in this endeavor. Heterosis refers to the superior performance of hybrid offspring compared to their parents, particularly in terms of yield and other agronomic traits (Huang et al., 2016; Gaballah et al., 2022). The integration of intersubspecific heterosis, which involves crossing different subspecies of rice, has shown promise in further enhancing the yield potential of hybrid rice varieties (Li et al., 2016; Qian et al., 2016). This study aims to explore the advancements in hybrid rice breeding by integrating intersubspecific heterosis with high-yield traits, thereby contributing to the development of superior hybrid rice varieties. Hybrid rice has played a crucial role in addressing global food security challenges. Since its introduction, hybrid rice has significantly increased rice production, particularly in countries like China, where it has been extensively adopted (Cheng et al., 2001; Zhou et al., 2022). The ability of hybrid rice to produce higher yields compared to conventional varieties makes it a vital component in the strategy to meet the rising food demands. The exploitation of heterosis in hybrid rice has not only improved yield but also enhanced other important traits such as disease resistance and stress tolerance, further contributing to its importance in sustainable agriculture (Wu, 2009; Huang et al., 2015). The continuous improvement and adoption of hybrid rice are essential to ensure a stable and sufficient food supply for the growing global population. Recent research has focused on understanding the genetic and molecular mechanisms underlying heterosis to optimize hybrid rice breeding. Studies have identified numerous quantitative trait loci (QTLs) and specific genes associated with yield heterosis, providing insights into the genetic architecture of hybrid vigor. The integration of intersubspecific heterosis, which involves crossing indica and japonica subspecies, has been partially exploited to develop high-yielding hybrid rice varieties. This approach has led to the identification of favorable alleles and the
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