Linkage Mapping and QTL Analysis of Agronomic Traits in Tetraploid Potato (Solanum tuberosum subsp tuberosum)

Potato (Solanum tuberosum L.) is one of the world's most important crops. Using a tetraploid population, we developed a linkage map using amplified fragment length polymorphism and simple sequence repeat (SSR) markers, and searched for quantitative trait loci (QTL) via interval mapping and single-marker analysis of variance. Quantitative trait loci were detected for flower color, foliage maturity, tuber skin texture, dry matter content, specific gravity, and yield. Most linkage groups were anchored to Solanum chromosomes using SSRs. The most significant QTL detected was for flower color. It was located on chromosome II and explained over 40% of the variation for this trait. This QTL most likely corresponds to the R locus for red anthocyanin production. We also confirmed the presence of QTL for foliage maturity on chromosomes III and V. For skin texture, a trait that has not been previously mapped in potato, we detected multiple QTL. One of these, found on chromosome III, explained 20% of the variation. By measuring specific gravity and dry matter independently we were able to detect QTL for these traits that did not co-locate, even though the traits are strongly correlated. Yield QTL were detected on multiple chromosomes, including a novel one on chromosome III. Many QTL could be modeled as simplex or duplex with dominant effects, but a large number displayed additive or interallelic interactive effects. The mapping and modeling of traits in this tetraploid population could be improved by the use of more codominant markers, such as single nucleotide polymorphisms.