Plant Gene and Traits 2024, Vol.15, No.4, 195-206 http://genbreedpublisher.com/index.php/pgt 199 This method is particularly advantageous for complex traits controlled by multiple genes with small effects, such as disease resistance in legumes (Budhlakoti et al., 2022). The application of GS in legume breeding has been bolstered by advances in next-generation sequencing and genotyping technologies, which have enabled the development of dense genetic maps and comprehensive genomic resources (Varshney et al., 2013). 6.2 Advantages of GS over traditional breeding methods GS offers several advantages over traditional breeding methods. Firstly, it increases the accuracy of selection by using genome-wide markers, which capture more genetic variation than a few selected markers. This leads to more precise predictions of breeding values and, consequently, more effective selection of superior genotypes (Crossa et al., 2017). Secondly, GS accelerates the breeding cycle by allowing early selection of individuals based on their genomic estimated breeding values (GEBVs), thus reducing the need for extensive phenotyping (Budhlakoti et al., 2022). This is particularly beneficial for traits that are difficult to measure or are influenced by environmental factors, such as disease resistance (Carpenter et al., 2018). Additionally, GS can be integrated with other modern breeding approaches, such as marker-assisted backcrossing and genomic-enabled prediction, to further enhance the efficiency of breeding programs (Varshney et al., 2013; Bekele et al., 2019). 6.3 Genomic selection for pest and disease resistance in legumes: recent advancements Recent advancements in GS have significantly improved the breeding of legumes for pest and disease resistance. For instance, GS has been successfully applied to improve resistance to ascochyta blight in pea, a disease that is challenging to assay due to its environmental dependency and the involvement of multiple pathogens. The use of GS models, such as genomic best linear unbiased prediction (GBLUP) and Bayesian methods, has shown promising results in predicting disease resistance with high accuracy (Carpenter et al., 2018). Similarly, GS has been employed to enhance resistance to Fusarium wilt and Ascochyta blight in chickpea, and late leaf spot and leaf rust in groundnut, demonstrating its potential to develop superior cultivars with enhanced tolerance to various diseases (Varshney et al., 2013). Moreover, the integration of GS with other genomic tools, such as genome-wide association studies (GWAS) and high-throughput phenotyping, has further refined the selection process. For example, the combination of GS with hyperspectral imaging technology has been proposed to improve the accuracy of genomic predictions and accelerate the breeding cycle (Crossa et al., 2017). These advancements underscore the transformative potential of GS in legume breeding, paving the way for the development of disease-resistant varieties that can thrive in diverse and challenging environments (Kankanala et al., 2019; Jha et al., 2022). 7 Genetic Engineering and CRISPR-Cas9 in Resistance Breeding 7.1 Introduction to transgenic approaches and CRISPR-Cas9 technology Genetic engineering has revolutionized the field of plant breeding, offering precise and efficient methods to enhance pest and disease resistance in crops. Traditional transgenic approaches involve the introduction of foreign genes into a plant's genome to confer desired traits. However, these methods often face regulatory hurdles and public resistance due to concerns over genetically modified organisms (GMOs). The advent of CRISPR-Cas9 technology has marked a significant advancement in genetic engineering. CRISPR-Cas9 allows for targeted genome editing by creating double-strand breaks at specific locations in the DNA, which are then repaired by the cell's natural mechanisms, leading to precise modifications. This technology is not only more efficient and cost-effective but also enables the development of transgene-free plants, addressing some of the concerns associated with traditional transgenic methods (Borrelli et al., 2018; Ahmad et al., 2020; Nascimento et al., 2023). 7.2 Engineering pest and disease resistance genes in legumes The application of CRISPR-Cas9 in legumes has shown promising results in enhancing resistance to various pests and diseases. By targeting specific genes associated with susceptibility, researchers can create mutations that confer resistance. For instance, the CRISPR-Cas9 system has been used to disrupt the function of genes that facilitate viral infections, thereby developing virus-resistant plants (Chandrasekaran et al., 2016; Borrelli et al., 2018). In legumes, specific genes related to pest and disease resistance have been identified and targeted using CRISPR-Cas9. For example, the UDP-glycosyltransferase (UGT) gene in soybeans has been edited to enhance
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