The grape (Vitis vinifera) is one of the earliest domesticated fruit crops and, since antiquity, it has been widely cultivated and prized for its fruit. The aim of this investigation was to characterize grape germplasm that have been under cultivation in Iran for a long time. Sixteen fruit parameters were studied in 23 grape cultivars. A high variability was found in the evaluated grape cultivars, and significant differences were found between them in all fruit attributes. Fruit yield, cluster size, berry size, total soluble solids (TSS), and titratable acidity (TA) showed a wide variation. Most cultivars had a relatively medium berry size; three had a berry weight higher than 3.50 g. Very diverse berry skin color were observed, white to black, while the dominant color of berry was yellowish green. There were high positive correlations between cluster and berry traits (weight and dimensions) and also negative correlation between TSS and TA. Cluster and principal component analyses showed a considerable fruit diversity in the studied grape germplasm. Parameters with high discriminating values were those related to berry size. The wide range in fruit trait characteristics of Iranian grapes might be considered as characterizing the large gene pool that contributed to the domestication process of grape. Also, clonal selection and conservation of the highly diverse autochthonous grapes are recommended.
