Quantitative trait loci analysis of potato tuber greening

A conversion of amyloplasts into chloroplasts in the potato tuber after light exposure is known as tuber greening and is one of the major causes of tuber loss. We report here the first mapping of the factors affecting tuber greening in potato. We used an F1 mapping population of diploid potatoes and DArTseq™ markers to construct a genetic map. The individuals of the mapping population, parents and standards were phenotyped for two tuber greening parameters: external tuber greening and internal greening depth on 0-5 scales in three years 2015, 2016 and 2018. The results were used for the analysis of Quantitative Trait Loci (QTLs) by an interval QTL mapping. Two most important QTLs were covering large regions of chromosomes VII and X and had the strongest effect on both greening parameters in data sets obtained in particular years and in the mean data set. Variance observed in the mean tuber greening could be ascribed in 16.9% to the QTL on chromosome VII and in 23.4% to the QTL on chromosome X. The QTL on chromosome VII explained 13.1%, while the QTL on chromosome X explained up to 17.7% of the variance in the mean tuber greening depth. Additional, minor QTLs were year- and/or trait-specific. The QTLs on chromosomes VII and X determine big parts of the observed tuber greening variation and should be investigated further in order to identify the genes underlying their effects but also should be taken into account when selecting non-greening potato lines in the breeding process.