Genetic control of tomato fruit quality : from GWAS to breeding
Résumé
Tomato flavor has changed over the course of domestication and later during breeding although it was not a target for breeders until recently. For years consumers complained about the taste of modern varieties. Flavour and nutritional quality thus became important goals for tomato breeders. Although tomato taste is influenced by environmental and post-harvest conditions, the varieties show a large diversity for sensory traits as welle as fruit composition. We will present our recent work intended to improve tomato fruit quality. Since the availability of large numbers of SNP, genome-wide association studies (GWAS) were performed on several panels of tomato lines. We thus performed a meta-analysis of GWAS for 18 traits, combining results on 775 tomato accessions and 2,316,117 SNPs from three GWAS panels. We discovered 305 significant associations for the contents of sugars, acids, amino acids and flavor-related volatiles. We showed for instance that fruit citrate and malate contents have been impacted by selection during domestication and improvement, while sugar content has undergone less stringent selection. Volatile organic compound contents also evolved and some trends for improvement were identified. More recently we checked the inheritance of volatiles at the hybrid level in order to help the production of F1 hybrids with good quality. We will discuss how to use these data to improve tomato quality.