Supplementary Material for Lamon et al., 2026

Although peanut (<i>Arachis hypogaea</i>) mainly shows disomic pairing, its segmental allotetraploid genome can occasionally form multivalents, allowing double reduction to occur. We detected double reduction using a backcross population between cultivated peanut and the neoallotetraploid [<i>A. magna</i> × <i>A. stenosperma</i>]^4x (MagSten) and a high-density phased linkage map containing 9,717 SNP markers.

Initial mapping artifacts were traced to progenies with unbalanced chromosomal compositions caused by homoeologous exchange; removing these individuals resolved the artifacts. Double reduction was detected in 12% of progenies. This deposit contains the supplementary tables and figures supporting the analysis.</p><p dir="ltr">Contents:</p><p dir="ltr">Supplementary Table 1 – Supplementary Table 4 — SNP dosage scores, the final marker set with map positions, pericentromere boundaries, and a summary of DR events by individual and linkage group.</p><p dir="ltr">Supplementary Figure 1 – Supplementary Figure 12 — Marker filtering and dosage-type distributions, concordance between genotype-calling phase and linkage-map phase, the genome-wide distribution of interspersed genotyping patterns, step-by-step construction of pseudo-integrated linkage maps across chromosomes via centromere alignment, heatmaps of cross-linkage-group LOD scores, and Hidden Markov Model analyses, including genotyping error-rate diagnostics and posterior identity-by-descent probability visualizations, used to independently evaluate candidate DR and homoeologous exchange events.</p><p dir="ltr">Supplementary Figure Legends — full legends for Supplementary Figure 1 – Supplementary Figure 12.</p>