Advanced Backcross Quantitative Trait Loci (QTL) Analysis of Oil Concentration and Oil Quality Traits in Peanut (Arachis hypogaea L.)

Peanut seed oil is an important commodity worldwide and breeding efforts have been to improve both the quality and quantity of oil produced. Identifying sources of variation and elucidating the genetics of oil concentration and quality in peanut is essential to advancing the development of improved genotypes. The objective of this study was to discover QTLs for oil traits in an advanced backcross population derived from a cross between a wild-species derived amphidiploid, TxAG-6, and a cultivated genotype, Florunner. A BC1F1 population was developed for genetic mapping and an advanced backcross BC3F6 population was phenotyped in three environments and genotyped using SSR markers. Composite interval mapping results identified three genomic regions associated with oil concentration in a combined analysis. Marker PM36, associated with oil concentration and multiple fatty acids in this study, mapped directly to a HD-ZIP transcription factor in diploid Arachis genome sequences. For fatty acid concentrations, results suggested 17 QTLs identified in two or more environments, 15 of which were present across environments. Fourteen genomic regions on 13 linkage groups contained significant QTLs for more than one trait, suggesting that same genes or gene families are responsible for multiple phenotypes. QTLs and the genes identified in this study could be effective tools in marker-assisted breeding targeted at pyramiding seed oil alleles from wild-species while minimizing introgression of non-target chromatin.