Legume Genomics and Genetics 2024, Vol.15, No.5, 232-243 http://cropscipublisher.com/index.php/lgg 233 wild species and synthetic polyploids in introducing genetic variation and enhancing peanut stress resistance, highlighting the promising prospects of these resources in improving the resilience of peanut crops to environmental challenges. 2 Genetic Diversity in Peanuts 2.1 Understanding genetic diversity Genetic diversity refers to the total number of genetic characteristics in the genetic makeup of a species. In peanuts (Arachis hypogaea L.), genetic diversity is crucial for breeding programs aimed at improving crop performance, disease resistance, and adaptability to various environmental conditions. The genetic architecture of peanuts, including its polyploid nature and self-pollination tendencies, has historically limited the genetic diversity within cultivated varieties (Pandey et al., 2012; Tawanna, 2024). 2.2 Sources of genetic variation in peanuts Wild relatives of peanuts, such as Arachis cardenasii and other species within the genus Arachis, are invaluable sources of genetic variation. These wild species harbor alleles that can confer resistance to biotic and abiotic stresses, which are often absent in cultivated varieties. For instance, the introduction of A. cardenasii into peanut breeding programs has led to the development of disease-resistant cultivars that have significantly improved food security and reduced fungicide use globally (Figure 1) (Bertioli et al., 2021). Additionally, wild species-derived induced allotetraploids have been used to introduce new traits, such as disease resistance and improved agronomic characteristics, into cultivated peanuts (Suassuna et al., 2020; Ballén-Taborda et al., 2023). Induced mutations and the development of advanced breeding lines are other critical sources of genetic variation. Techniques such as genotyping-by-sequencing (GBS) and the use of molecular markers have facilitated the identification of single nucleotide polymorphisms (SNPs) and quantitative trait loci (QTLs) associated with desirable traits. For example, advanced backcross populations have been used to map QTLs for traits like pod constriction and yield components, revealing the potential of wild alleles to enhance peanut productivity and adaptation (Fonceka et al., 2012; Brown et al., 2021; Yang, 2024). Figure 1 Global dispersal of A. cardenasii GKP 10017 and its genetic contribution to the peanut crop (Adopted from Bertioli et al., 2021) Image caption: Counts are of cultivars and lines, which are registered and/or publicly available and do not include lineages that are confined to a single breeding program or lineages from segregating populations (Adopted from Bertioli et al., 2021)
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