Impact of Hull thickness, seed weight, and total sound mature kernels on generation of loose shelled kernels during peanut harvest

Abstract Generation of loose shelled kernels (LSK) during peanut harvest increases the probability of seed exposure to aflatoxin‐producing Aspergillus spp. fungi; therefore, LSK are a risk factor for aflatoxin contamination. This study investigated the impact of various genotypic pod and seed physical characteristics on generation of LSK. During 2022 and 2023 in Marianna, FL, a randomized complete block design with a split plot treatment arrangement evaluated nine advanced genotypes, which varied in hull thickness and pod/seed size, and harvest timing. LSK percentage and seed and hull characteristics were measured after harvest, and a subsample was collected for grading. In general, genotypes with thicker hulls and smaller seeds produced fewer LSK. However, genotypes with thicker hulls alone and independent of seed size had lower LSK compared to genotypes with thinner hulls. Similarly, genotypes with seed weight of around 62 g per 100 seed or less had lower LSK than genotypes with larger seed. The genotype that combined small seed with thick hulls had the lowest LSK of all genotypes. Thin hull is a prerequisite for higher grades in peanut, and grade determines the market value of the crop. Therefore, breeding for genotypes with thicker hulls would require a change in how the peanut crop is valued with a clear tradeoff in the value gained due to reduction in aflatoxin risk from lower LSK and the value lost in grade caused by a higher proportion of hulls versus edible peanuts (total sound mature kernels). Correlation and regression analyses were conducted to explore this tradeoff biologically and to help inform breeding efforts to select genotypes that minimize LSK risk.