A novel introgression line collection to unravel the genetics of climacteric ripening and fruit quality in melon

Introgression lines are valuable germplasm for scientists and breeders, since they ease genetic studies such as QTL interactions and positional cloning as well as the introduction of favorable alleles into elite varieties. We developed a novel introgression line collection in melon using two commercial European varieties with different ripening behavior, the climacteric cantalupensis ‘Védrantais’ as recurrent parent and the non-climacteric inodorus ‘Piel de Sapo’ as donor parent. The collection contains 34 introgression lines, covering 99% of the donor genome. The mean introgression size is 18.16 Mb and ~ 3 lines were obtained per chromosome, on average. The high segregation of these lines for multiple fruit quality traits allowed us to identify 27 QTLs that modified sugar content, altered fruit morphology or were involved in climacteric ripening. In addition, we confirmed the genomic location of five major genes previously described, which control mainly fruit appearance, such as mottled rind and external color. Most of the QTLs had been reported before in other populations sharing parental lines, while three QTLs (EAROQP11.3, ECDQP11.2 and FIRQP4.1) were newly detected in our work. These introgression lines would be useful to perform additional genetic studies, as fine mapping and gene pyramiding, especially for important complex traits such as fruit weight and climacteric ripening.This work was supported by the Spanish Ministry of Economy and Competitiveness Grants AGL2015-64625-C2-1-R and RTI2018-097665-B-C2, Severo Ochoa Programme for Centres of Excellence in R&D 2016–2010 (SEV-2015-0533) and the CERCA Programme/Generalitat de Catalunya to J.G.-M. L.P., L.V. and M.S.D. were supported by a FPI grant from the Spanish Ministry of Economy and Competitiveness, and CM was supported by 2019 FI_B 00124 project from the Secretaria d'Universitats i Recerca del Departament d'Empresa i Coneixement de la Generalitat de Catalunya and the co-funding of the European Social Fund (ESF—“ESF is investing in your future”) from the European Union.Peer reviewe