Image phenotyping of inbred red lettuce lines with genetic diversity regarding carotenoid levels

•High performance phenotyping enables non-destructive analysis of plants.•Image phenotyping assists indirect selection of carotenoid-rich lettuces.•Image phenotype has high correlation with the carotenoid content in lettuce.•Phenotyping by image allows to identify genetic backgrounds in germplasm.•Image phenotyping determines the level of biofortification in producing regions.