Outline analysis of the grapevine (Vitis vinifera L.) berry shape by elliptic Fourier descriptors

Grapevine berry morphology is one of the most important features in table grape production. In this study, berry samples of 46 grapevine accessions were investigated for 3 consecutive years with elliptic Fourier descriptors (EFD) to evaluate shape diversity. Ten reference shapes obtained from the OIV descriptor list were involved and principal component (PC) scores summarizing the EFD's were statistically evaluated with Two way ANOVA and discriminant analysis. The cummulative contribution of the five principal components was 96.83 %. Two way ANOVA revealed that berry shape had high variability within the accessions and years. Based on the linear discriminant analysis, reference shapes were compared to those of the accessions and graphic reconstruction was carried out. OIV references were considered as unknown samples and grouped into the accession classes. Overall correct classification of the accessions into their group was 13.88 %. Our results showed that EFD together with reference shapes are a powerful method to discribe berry shape and possibly give the future basis of uvometric evaluation of grapevine cultivars.