Abstract
In peanut, limited genetic variation for disease resistance is available in breeding programs necessitating the identification of stable resistance sources for use in cultivar development. ‘Tifrunner’ is a runner cultivar while ‘GT-C20’ is a Spanish-type breeding line with resistance to aflatoxin contamination. We screened a RIL population generated from Tifrunner × GT-C20 for aflatoxin contamination resistance using a laboratory kernel screening assay. We scored visible fungal growth on kernels, and aflatoxin content using a fast methanol extraction method and a fluorometer (verified by TLC and ELISA). This phenotypic screening was repeated three times, each with three biological replicates. We found that surface sporulation ratings were normally distributed across the population. Aflatoxin levels varied among the RILs with a distribution skewed toward lower aflatoxin levels. Quantitative trait locus (QTL) analysis for all replicates identified a total of 16 QTLs, five QTLs for aflatoxin contamination and eleven for fungal growth. Of these, five QTLs were major QTLs with more than 10% phenotypic variation explained (PVE). From these five major QTLs, one was found for aflatoxin contamination with 10.14% PVE, and three QTLs for the fungal growth (PVE = 13.23%, 11.21% and 14.17%, respectively). These novel QTLs will be compared with recently released peanut diploid genome to identify putative resistance genes, and validated for potential applications in breeding.