title: A major QTL controlling apple skin russeting maps on the linkage group 12 of 'Renetta Grigia di Torriana'.
abstract: BACKGROUND
  Russeting is a disorder developed by apple fruits that consists of cuticle cracking followed by the replacement of the epidermis by a corky layer that protects the fruit surface from water loss and pathogens. Although influenced by many environmental conditions and orchard management practices, russeting is under genetic control. The difficulty in classifying offspring and consequent variable segregation ratios have led several authors to conclude that more than one genetic determinant could be involved, although some evidence favours a major gene (Ru).
  
  
  RESULTS
  In this study we report the mapping of a major genetic russeting determinant on linkage group 12 of apple as inferred from the phenotypic observation in a segregating progeny derived from 'Renetta Grigia di Torriana', the construction of a 20 K Illumina SNP chip based genetic map, and QTL analysis. Recombination analysis in two mapping populations restricted the region of interest to approximately 400 Kb. Of the 58 genes predicted from the Golden Delicious sequence, a putative ABCG family transporter has been identified. Within a small set of russeted cultivars tested with markers of the region, only six showed the same haplotype of 'Renetta Grigia di Torriana'.
  
  
  CONCLUSIONS
  A major determinant (Ru_RGT) for russeting development putatively involved in cuticle organization is proposed as a candidate for controlling the trait. SNP and SSR markers tightly co-segregating with the Ru_RGT locus may assist the breeder selection. The observed segregations and the analysis of the 'Renetta Grigia di Torriana' haplotypic region in a panel of russeted and non-russeted cultivars may suggest the presence of other determinants for russeting in apple.
authors.affiliation: Department of Agriculture and Environmental Sciences, University of Udine, Via delle Scienze 208, 33100, Udine, Italy. luigi.falginella@uniud.it.
authors.forename: Luigi
authors.initials: L
authors.lastname: Falginella
authors.affiliation: Department of Agriculture and Environmental Sciences, University of Udine, Via delle Scienze 208, 33100, Udine, Italy. guido.cipriani@uniud.it.
authors.forename: Guido
authors.initials: G
authors.lastname: Cipriani
authors.affiliation: Department of Agriculture and Environmental Sciences, University of Udine, Via delle Scienze 208, 33100, Udine, Italy. monte.corinne@spes.uniud.it.
authors.forename: Corinne
authors.initials: C
authors.lastname: Monte
authors.affiliation: Department of Agricultural Sciences, University of Bologna, Via Fanin 44, 40127, Bologna, Italy. roberto.gregori4@unibo.it.
authors.forename: Roberto
authors.initials: R
authors.lastname: Gregori
authors.affiliation: Department of Agriculture and Environmental Sciences, University of Udine, Via delle Scienze 208, 33100, Udine, Italy. raffaele.testolin@uniud.it.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Testolin
authors.affiliation: Research and Innovation Centre - Fondazione Edmund Mach - Department of Genomics and Biology of Fruit Crop, Via E. Mach 1, 38010 S, Michele all'Adige TN, Italy. riccardo.velasco@fmach.it.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Velasco
authors.affiliation: Research and Innovation Centre - Fondazione Edmund Mach - Department of Genomics and Biology of Fruit Crop, Via E. Mach 1, 38010 S, Michele all'Adige TN, Italy. michela.troggio@fmach.it.
authors.forename: Michela
authors.initials: M
authors.lastname: Troggio
authors.affiliation: Department of Agricultural Sciences, University of Bologna, Via Fanin 44, 40127, Bologna, Italy. stefano.tartarini@unibo.it.
authors.forename: Stefano
authors.initials: S
authors.lastname: Tartarini
mesh_terms: D002874:Chromosome Mapping; D020090:Chromosome Segregation / Q000235:genetics; D032461:Chromosomes, Plant / Q000235:genetics; D003433:Crosses, Genetic; D019992:Databases as Topic; D056726:Genetic Association Studies; D008040:Genetic Linkage; D056426:Genetic Loci; D005819:Genetic Markers; D006239:Haplotypes / Q000235:genetics; D027845:Malus / Q000235:genetics*; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics*; D040641:Quantitative Trait Loci / Q000235:genetics*
chemical_list: D005819:Genetic Markers