Genetic variability of berry size in the grapevine (Vitis viniferaL.)

Background and Aims Berry weight in the grapevine, as in the tomato, is variable, ranging from less than 1g to 10g. In the tomato, berry weight depends on cell number and volume but also on carpel number. The aim of this work was to decipher the range of variation and to propose a role for subtraits possibly underlying berry size variation in a highly diverse collection of cultivated grapevines. Methods and Results Cell division before and after anthesis and cell expansion after anthesis appeared to be the major determinants of flesh weight variation between cultivars. Carpel number varied between cultivars, with two and three carpels per ovary. This trait, however, and also the seed weight did not clearly contribute to berry size variation, although a positive correlation was found between seed weight and number and berry weight at the intragenotypic level, in agreement with previous results. Conclusions This work deciphered the main anatomical factors underlying variation in berry size in Vitis vinifera; they involved both common fleshy fruits factors but also specific vine factors. Significance of the Study Further studies of the variation in berry size of the the grape will be assisted by the anatomical factors identified in this study.