Blueberry genetics: germplasm evaluation and QTL mapping

Cultivation and consumption of highbush blueberry (V. corymbosum ) have been greatly increased in the last years with most of the breeding programs particularly focusing on fruit quality and plant adaptability to more extreme environmental conditions. Thus, there is the urgent need to exploit the genetic diversity present in the blueberry germplasm and to delve deeper into the genetic determination of several key traits to generate robust markers for MAB (Marker Assisted Breeding). The present research aimed to genetically characterize the FEM Vaccinium spp. germplasm and to dissect the genetics of phenology related traits and fruit quality (texture, VOCs, soluble solids , etc.) at harvest and postharvest by QTL mapping. One hundred ten accessions have been genotyped with 13 SSR markers and could be separated in clusters reflecting species/ploidy and plant attitude (northern highbush –NHB- and southern highbush –SHB-). The F1 mapping population generated from a cross between two tetraploid cultivars: the NHB “Draper” and the SHB “Biloxi”. Two sets of 96-plex GBS libraries from the two parents and 186 individuals of the progeny were single-end sequenced for 100 bp. Finally, 5977 SNP markers were located in an integrated genetic map of 12 linkage groups (LGs) with 43 and 44 out of 48 expected homologues found for Draper and Biloxi respectively. Suggestive QTLs have been found and together with the above mentioned results represent a pivotal step towards providing the framework for MAB in blueberry