Screening and QTL mapping for mechanical shelling damage related traits in peanut

To further identify agronomic traits influencing mechanical shelling quality in peanut and explore their genetic basis, this study evaluated 63 advanced-generation lines and focused on three pod- or kernel-related traits: shelling percentage, pod crushing force, and kernel crushing force. Correlation analysis revealed that only kernel crushing force was significantly associated with the damaged kernel rate. Two lines (D9 and E10) with low damaged kernel rates (&lt; 2.50%) were identified. Additionally, a recombinant inbred line (RIL) population of 181 individuals derived from a cross between cultivars Huayu 36 and 6-13 was used for QTL mapping of the kernel crushing force trait. Phenotypic data were collected from 2020 to 2023 across four locations: Yantai, Weihai, Dongying, and Qingdao. The trait exhibited continuous variation and transgressive segregation in the RIL population, with a broad-sense heritability of 0.88. Using a previously published high-density genetic map, eight additive QTLs associated with kernel crushing force were identified, explaining 6.04% to 28.30% of the phenotypic variation. Among them, two major QTLs, <italic>qKCF7</italic> and <italic>qKCF16.1</italic>, were stably expressed across multiple environments, with favorable alleles derived from Huayu 36. In addition, 12 pairs of epistatic QTLs involving 24 SNP intervals were detected, explaining 1.55% to 4.01% of the phenotypic variation. These findings provide valuable genetic targets and germplasm resources for the future genetic improvement of traits related to mechanical shelling quality in peanut.