Triticeae Genomics and Genetics, 2024, Vol.15, No.5, 244-254 http://cropscipublisher.com/index.php/tgg 250 6 Applications of Polyploidy inTriticeae Crop Breeding 6.1 Case studies of successful breeding improvements through polyploidy Polyploidy has been instrumental in the breeding of various Triticeae crops, leading to significant improvements in yield, quality, and stress resistance. For instance, synthetic polyploids have been used to enhance specific traits in crop varieties, such as environmental adaptation and yield, by modifying certain plant phenotypes while maintaining fundamental characteristics (Ruiz et al., 2020). In wheat, the use of hexaploid varieties has facilitated the identification of homoeologous relationships between chromosomes, aiding in the transfer of valuable agronomic traits from related species (Naranjo, 2019). Additionally, polyploidy has been employed to overcome the non-viability and infertility of interspecific hybrids, resulting in the development of seedless polyploid cultivars and increased resistance to biotic and abiotic factors (Trojak-Goluch et al., 2021). 6.2 Technical challenges and solutions in incorporating polyploidy into breeding programs Incorporating polyploidy into breeding programs presents several technical challenges, including the complexities of genome assembly and the potential for undesired phenotypic effects. The genome-wide analysis of polyploid crops has historically lagged behind that of diploid crops due to difficulties in genome assembly, which arise from the combination of evolutionarily diverged genomes into a single nucleus and the significant size of polyploid genomes (Renny-Byfield and Wendel, 2014). However, advancements in next-generation sequencing and other molecular tools have begun to address these challenges, enabling better understanding and manipulation of polyploid genomes (Renny-Byfield and Wendel, 2014; Kyriakidou et al., 2018). Additionally, the use of antimitotic agents such as colchicine, oryzalin, and trifluralin has been effective in inducing polyploidy, although the efficiency of genome duplication can vary based on species, cultivar, genotype, and tissue type (Trojak-Goluch et al., 2021). 6.3 Future potential of polyploid crops in breeding programs The future potential of polyploid crops in breeding programs is vast, particularly in the context of climate change and the need for crops that can withstand biotic and abiotic stresses. Polyploidy offers the potential for increased allelic diversity, heterozygosity, and novel phenotypic variation, which are crucial for crop improvement (Udall and Wendel, 2006). The generation of synthetic polyploids as a breeding strategy has already led to the development of new and improved cultivars, and ongoing research aims to further explore the mechanisms underlying polyploidy-induced novelty (Iannicelli et al., 2020). As our understanding of polyploid genomes continues to grow, particularly through the use of modern genomic technologies, the ability to harness the benefits of polyploidy for crop breeding will likely expand, offering new opportunities for the development of resilient and high-yielding Triticeae crops (Bharadwaj, 2015; Heslop-Harrison et al., 2022). 7 Challenges in Managing Polyploidy inTriticeae Breeding Programs 7.1 Difficulties in mapping complex traits in polyploid genomes Mapping complex traits in polyploid genomes presents significant challenges due to the intricate nature of polyploid inheritance and the presence of multiple homologous chromosomes. Polyploid organisms, such as those in the Triticeae tribe, often exhibit complex genetic interactions that complicate the identification and mapping of quantitative trait loci (QTL). The presence of multiple gene copies and structural variations, such as homeologous exchanges, further complicates genetic mapping efforts (Bourke et al., 2018; Schiessl et al., 2019). Advanced genomic tools and techniques, including genome-wide association studies (GWAS) and quantitative trait analysis, are essential to overcome these challenges and facilitate the accurate mapping of complex traits in polyploid Triticeae species (Bourke et al., 2018). 7.2 Breeding barriers due to complex inheritance patterns in polyploid species Polyploid species exhibit complex inheritance patterns that pose significant barriers to breeding programs. The presence of multiple sets of chromosomes can lead to genome instabilities, chromosome imbalances, and regulatory incompatibilities, which in turn affect reproductive success and fertility (Comai, 2005; Chen, 2007). Additionally, the intricate interactions between redundant genes and the potential for non-Mendelian inheritance patterns further complicate breeding efforts (Wendel, 2004). These challenges necessitate the development of
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