Vitis vinifera cluster's wing-related structural characteristics and their associations with yield and berry composition

The hypotheses considered in this article concern the basic question, besides bearing a wing, in what ways do wing-bearing and non-wing-bearing clusters differ? Vines sampled at midseason were again selected at harvest. Each weight of a Vitis vinifera cluster sampled at midseason was multiplied by the number of clusters on the vine from which the cluster had been selected. Correlation coefficients between this quantity and the sampled vine's yield at harvest differed significantly in the sense that coefficients determined solely from the subset of sampled clusters on which a wing (a lateral arm originating from the peduncle and separate from the main body of the cluster) was present were found to be larger than coefficients determined from all sampled clusters. To shed light on distinguishing characteristics of clusters that bore wings, the weights of clusters that had been sampled at midseason were studied. Despite being weighed after the removal of their wings, clusters that had wings were found to be significantly heavier than clusters (sampled at the same midseason date) that had never had wings. Box and whisker plots were constructed to assess this finding as well to study the relationships between a Vitis vinifera rachis' (a cluster's principal axis) weight, length, and diameter and wing absence or presence. For each of the five vineyard blocks that we studied, the median rachis midseason diameters of wing-bearing clusters exceeded the median rachis diameters of non-wing-bearing clusters. Concerning ‘Cabernet Sauvignon’ Vitis vinifera clusters that had wings, it was also found that the late-season differences between the median soluble solids concentrations (°Brix) of wing-borne berries and the median °Brix of non-wing-borne berries were inappreciable.