Molecular Plant Breeding 2024, Vol.15, No.3, 100-111 http://genbreedpublisher.com/index.php/mpb 102 pigmentation, a complex quantitative trait (Mangino et al., 2021). The increased recombination events in MAGIC populations, as observed in tomato, lead to a higher resolution in QTL mapping compared to bi-parental populations (Pascual et al., 2015). 3.3 Benefits in terms of breeding cycle time and efficiency The MAGIC populations are not only valuable for genetic analysis but also for their direct and indirect use in breeding programs. For instance, the rice MAGIC populations have been developed with the purpose of fine mapping QTLs and using the highly recombined lines in breeding programs, thus promising breakthroughs in genetic gain (Bandillo et al., 2013). The MAGIC population in tomato has been used to develop genotypes with important agronomic traits and to perform Participatory Plant Breeding (PPB), demonstrating its utility in breeding cycles (Campanelli et al., 2019). Furthermore, the MAGIC population in winter wheat has captured a significant portion of the allelic diversity available in the breeding gene pool, which is beneficial for carrying out genetic studies for a wide range of economically important traits (Stadlmeier et al., 2018). In conclusion, MAGIC populations are instrumental in enhancing genetic diversity, improving the resolution of QTL mapping, and increasing the efficiency of breeding programs. These populations are paving the way for the development of new generations of improved crop varieties, which is crucial for meeting the increasing global agricultural demands. 4 Case Studies 4.1 Examples of successful implementation of MAGIC populations in various crops MAGIC populations have been successfully implemented in various crops, demonstrating their utility in enhancing plant breeding efficiency. For instance, in cowpea (Vigna unguiculata L. Walp.), a MAGIC population was developed from eight genetically diverse founder parents, which carried traits for abiotic and biotic stress resistance, seed quality, and agronomic traits. This population resulted in 305 F8 RILs, each carrying a mosaic of genome blocks from all founders, leading to the identification of QTLs for several parental traits (Figure 1) (Huynh et al., 2018). The study presented in Figure 1 effectively illustrates the impact of environmental conditions and genetic diversity on the phenotypic expression in cowpeas. By utilizing a MAGIC population, the research showcases a broad spectrum of phenotypic variability, which is crucial for understanding the genetic basis of trait differentiation and for enhancing crop improvement strategies. This approach not only helps in identifying specific traits that can be targeted for genetic improvement but also underscores the importance of considering environmental interactions in breeding programs. The detailed morphological observations under different conditions provide valuable insights into the adaptability and growth dynamics of cowpea, which are essential for developing resilient crop varieties suited to varying climatic conditions. In sorghum (Sorghum bicolor (L.) Moench), the first MAGIC population was created by intercrossing 19 diverse founder lines, followed by 10 generations of random mating. This led to the development of 1 000 immortal MAGIC inbred lines, which were found to be rich in allelic content and highly recombined, making them suitable for gene mapping and marker-assisted breeding (Figure 2) (Ongom and Ejeta, 2017). The case studied by Ongom and Ejeta (2017) is a significant contribution to the field of plant breeding, particularly in the development of sorghum varieties. The use of a MAGIC population approach combined with genetic male sterility represents an advanced breeding strategy that allows for the integration of a wide range of genetic diversity. This methodology is particularly useful in capturing the extensive genetic variation necessary for improving complex traits such as drought tolerance, pest resistance, and yield stability under varying environmental conditions. By employing genetic male sterility, the researchers have efficiently managed the pollination process, ensuring a higher degree of control over the breeding outcomes. The subsequent cycles of random mating and selfing, followed by the single-seed descent method, have potentially accelerated the attainment of genetic homogeneity while maintaining diversity among the lines. This approach could pave the way for more precise and efficient selection processes in crop improvement programs.
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