High-Density SNP-Based Genetic Map for Identification of Fruit Quality-Related QTLs in Table Grape

Genetic analyses in grapevine were mainly focused in quality for wine and resistance to major fungal diseases. Table grape breeding programs are currently using molecular markers for resistance but barely for fruit quality related traits, mainly because identified QTLs explain only a small portion of the variability or are not reproducible among progenies or through the years. Poor QTL detection is caused by the lack of large progenies to perform association analyses. With the aim to reveal the genetic architecture of table grape quality traits we recently developed one the largest experimental progenies for the specie, more than a thousand unique genotypes, derived from the cross of Muscat of Alexandria and Crimson Seedless, were established. A reference genetic map was developed with the genotyping of a more than 600 genotypes with the Illumina 18K chip. More than 1,800 non-redundant markers were mapped in each parental genotype and more than 2,100 in the integrated map achieving an average density of less than a centimorgan between SNPs. Maps were aligned and corrected with the scaffolds of the V. vinifera reference genome sequence (V2) prior to perform QTL analysis. QTLs for berry size (berry weight, polar and equatorial diameter), firmness, acidity, seedlessness, flowering time, bud basal fertility were detected. Other traits related to aroma, texture and ripening date are being also analyzed. This progeny provides a valuable resource for further genetic studies and the development of marker assisted breeding for table grape.

Financed by FONDEF G09i1007 and FONDECYT 1120532