Phenomics of fruit shape in eggplant (Solanum melongena L.) using Tomato Analyzer software

• Tomato Analyzer is a useful software to characterize fruit shape diversity in eggplant.
• We studied 26 fruit shape traits in 21 eggplant accessions from four varietal groups.
• Significant differences among accessions and groups have been found for most traits.
• Multivariate analyses differentiate groups and classify most fruits correctly.
• This is the first phenomics study of fruit shape in eggplant.

Detailed characterization of fruit shape in eggplant (Solanum melongena) is important for horticulturists and breeders. In fact, commercial varieties are classified according to their fruit shape. However, traditional morphological descriptors provide limited information on this complex attribute. Recently, a software tool (Tomato Analyzer) for the processing of scanned images of sections of tomato fruits has been developed. Tomato Analyzer is adequate for phenomics studies of fruit shape, as it provides quantitative and objective data for a large number of fruit morphology traits. We used Tomato Analyzer for evaluating fruit shape in a collection of 21 accessions of eggplant from four varietal groups (Round, Listada de Gandía, Semi-long, and Long). For each accession we evaluated 20 fruits, for which we measured fruit weight, length, and width (manually), and 23 fruit shape parameters using the Tomato Analyzer. Significant differences among accessions have been found for all traits, except for Shoulders Height. For many traits, high values for the coefficient of genotypic variation (CVG) and broad-sense heritability (H2) have been obtained, indicating that selection will be efficient. Significant differences have also been found among varietal groups for 20 out of the 26 traits, and for six of them each of the four varietal groups differed significantly from the others. Multivariate principal components analysis (PCA) shows that accessions of each of the four varietal groups plot together and in separate areas of the PCA graph, with the exception of some overlapping between Round and Listada de Gandía accessions. Discriminant analysis resulted in 57.14% of the individual fruits being correctly assigned to their accession, and of those incorrectly classified, 21.67% were correctly classified to their varietal group. The results obtained show that the Tomato Analyzer image software tool is of great utility for phenomics studies of fruit shape in eggplant, which is of interest for characterization of germplasm and cultivars, and for selection and breeding.