Mapping and Analysis of QTL for Early Maturity Trait in Tetraploid Potato (Solanum tuberosum L.)

Abstract: Maturity is one of the important traits of potato. In order to get the genetic segment of potato early maturity trait, a tetraploid potato maturity segregation population of Zhongshu 19 × Zhongshu 3 was used for genetic analysis through the combination of high throughput simplified genome sequencing (2b-RAD) and bulked segregation analysis (BSA). A genetic segment related to the early maturity trait at the 3.7~4.2 Mb locus on the short arm of chromosome 5 was obtained and eight markers were developed based on this segment, while five of them were closely linked to the early maturity trait loci. Moreover, 42 SSR markers were developed based on the reference sequence of DM. Finally, a genetic map of chromosome 5 contained 50 markers was constructed using the Tetraploidmap software. The total map length was 172 cM with an average genetic distance of 3.44 cM. Combining with phenotypic data of the segregation population, we mapped the early maturity trait QTL with the contribution of 33.55% on the short arm of chromosome 5, located at 84cM between the flanking markers SSR5-85-1 and SCAR5-8 with the physical interval of 471kb. Gene annotation showed that there exist 34 genes in this region, 12 of them are unknown function. Among the other 22 annotated genes, E3 ubiquitin ligase gene PUB14 may be related to maturity and regulate tuber formation. Our fine mapping of the early maturity QTL made a solid foundation for cloning of the early maturity controlled gene or genes.