Legume Genomics and Genetics 2024, Vol.15, No.6, 291-302 http://cropscipublisher.com/index.php/lgg 292 This study summarizes the latest research advancements and technological progress in genomics, focusing on how these developments assist in identifying and utilizing effective drought-resistant markers. It analyzes the genetic diversity and key traits related to drought tolerance in soybeans, while exploring future research directions and potential strategies to enhance drought resilience. The aim is to investigate the role and contribution of marker-assisted selection (MAS) technology in breeding drought-tolerant soybean varieties. 2 Soybean and Drought Stress 2.1 Overview of soybean cultivation and its economic importance Soybean (Glycine max L.) is a globally significant crop, contributing approximately 57% of the total oilseed production worldwide (Shaheen et al., 2016). It is a major source of protein and oil, making it crucial for both human consumption and animal feed. The economic importance of soybean is underscored by its role in food security and its extensive use in various industries, including food, feed, and biofuel production (Dubey et al., 2019). The crop's adaptability to different climatic conditions and its ability to fix atmospheric nitrogen through symbiosis with rhizobia make it a valuable component of sustainable agricultural systems (Valliyodan et al., 2016). 2.2 Physiological and biochemical responses of soybean to drought stress Drought stress significantly impacts soybean growth and productivity by altering its physiological and biochemical processes. Under drought conditions, soybean plants exhibit reduced photosynthetic activity, leaf production, and water content, leading to stunted growth and lower dry matter production (Figure 1) (Arya et al., 2021). Biochemically, drought stress induces the accumulation of osmoprotectants such as proline and malondialdehyde (MDA), which help mitigate oxidative damage (Wang et al., 2022; Fatema et al., 2023). Additionally, drought stress enhances the activity of antioxidant enzymes like peroxidase (POD), catalase (CAT), and Ascorbic Acid Peroxidase (APX), which play crucial roles in protecting the plant from oxidative stress (Wang et al., 2022). High-yielding and drought-tolerant soybean varieties have been shown to maintain better root and shoot growth, higher photosynthesis rates, and greater water use efficiency under drought conditions (Buezo et al., 2018). 2.3 Challenges in breeding for drought tolerance in soybean Breeding for drought tolerance in soybean presents several challenges due to the complex nature of drought resistance traits, which are often quantitative and influenced by multiple genetic and environmental factors (Manavalan et al., 2009). Traditional breeding methods, which rely on direct selection for yield stability across multiple locations, are time-consuming and labor-intensive. The low heritability of yield under drought conditions further complicates the breeding process. Advances in genomic technologies, such as the availability of the whole soybean genome sequence and high-throughput phenotyping, have facilitated the identification of quantitative trait loci (QTLs) and candidate genes associated with drought tolerance (Xiong et al., 2020). However, integrating these genomic tools with conventional breeding approaches requires a comprehensive understanding of the physiological and molecular mechanisms underlying drought tolerance (Arya et al., 2021). Additionally, the limited genetic variability in soybean germplasm poses a significant hurdle, necessitating the exploration of diverse genetic resources to enhance drought tolerance (Valliyodan et al., 2016). Despite these challenges, the development of drought-tolerant soybean cultivars through marker-assisted selection and genetic engineering holds promise for improving soybean resilience to water-limited conditions (Shaheen et al., 2016; Dubey et al., 2019). 3 Marker-Assisted Selection: Concept and Applications 3.1 Definition and principles of marker-assisted selection Marker-assisted selection (MAS) is a process in plant breeding that uses molecular markers to select plants with desirable traits. The principle behind MAS is to identify specific DNA sequences (markers) that are linked to traits of interest, such as drought tolerance, and use these markers to guide the selection process. This allows for more precise and efficient breeding compared to traditional methods, as it enables the early identification of plants that carry the desired traits (Ribaut and Ragot, 2006; Torres et al., 2010).
RkJQdWJsaXNoZXIy MjQ4ODYzNA==