Genetic Analysis of Tuber Sprout Elongation and Dormancy Release in Potato

This work is published in the following article:Sharma, S.K., McLean, K., Colgan, R., Rees, D., Young, S., Sønderkær, M., Terry, L., Turnbull, C., Taylor, M. & Bryan G. 2021. Combining Conventional QTL Analysis and Whole-Exome Capture-based Bulk-Segregant Analysis Provides New Genetic Insights into Tuber Sprout Elongation and Dormancy Release in a Diploid Potato Population. Heredity (In Press)Abstract:Tuber dormancy and sprouting are commercially important potato traits as long-term tuber storage is necessary to ensure year-round availability. We have performed a detailed genetic analysis of tuber sprout growth using a diploid potato population derived from two highly heterozygous parents. A dual approach employing conventional QTL analysis allied to a combined bulk-segregant analysis (BSA) using a novel potato whole-exome capture (WEC) platform was evaluated. Tubers were assessed for sprout growth in storage at six time-points over two consecutive growing seasons. Genetic analysis revealed the presence of main QTL on five chromosomes, several of which were consistent across two growing seasons. Additionally, phenotypic bulks displaying extreme sprout growth phenotypes along with the parental clones of the mapping population were subjected to WEC sequencing for performing BSA. The combined BSA and WEC approach corroborated QTL locations and served to narrow the associated genomic regions, while also identifying new QTL for further investigation. Overall, our findings reveal a very complex genetic architecture for tuber sprouting and sprout growth, which has implications both for potato and other root, bulb and tuber crops where long-term storage is essential.