MetaQTL analysis provides a compendium of genomic loci controlling fruit quality traits in apple

Fruit quality represents an important aspect of any fruit species, due to its economical importance and direct impact on consumers' appreciation. In order to generate a compendium about the genomic intervals putatively involved in the control of the several fruit quality components, a Meta-quantitative trait loci (QTL) analysis was performed starting from a QTL mapping survey individually conducted on four full-sib populations. These progenies were simultaneously genotyped with 1289 SNP markers, of which 52 % were in common for at least two maps. The combination of the genotypic and phenotypic datasets allowed the identification of 56 QTLs, which were subsequently projected into a consensus map, reducing the total number of genomic intervals to 27 MetaQTLs. The majority of these regions, associated to fruit quality traits such as fruit skin color and flesh firmness, resulted also consistent with previous reports presented to date to the scientific community. This MetaQTL overview would represents a valuable source for genome anchoring and data mining investigation, suitable for a further in silico identification of relevant causal genes. As example is reported the case of Md-PG1, a gene known to control fruit firmness in apple and retrieved within the confidence interval of a MetaQTL associated to fruit firmness.