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Background and Aims: Viticulturists and winemakers have a considerable interest in understanding the influence of climate, soil, viticultural and winemaking practices on wine sensory outcomes—that is, understanding the terroir concept, which is important for regionality and claims of product distinctiveness. In this investigation, an empirical study of grape and wine composition, including sensory evaluations, was used to inform the delineation of subregional areas of the Barossa Zone geographical indicator (GI). Methods and Results: A spatiotemporal investigation of Shiraz was undertaken with vineyard zones selected to exemplify maximum heterogeneity within a site. Objective measures of vine performance and grape and wine composition were clustered using the k‐means approach, and up to three clusters of vineyard sites were evident within the dataset. Clusters were associated with vineyard elevation and thus growing temperatures. The most important measures of composition defining each cluster were the volatiles ethyl octanoate, diethyl succinate, 1,8‐cineole and 3‐methyl butyl acetate in grapes. Sensory attribute intensity differences were apparent for wines from some subregions, and projection of the important attributes for clusters defined in this study to key sensory differences shows a high variance in composition related to sensory features from year to year. The spatial outcomes of clusters for vineyard sites align with of some outcomes of prior clustering approaches using data‐rich sources for precision agriculture. Conclusions: Subregional zones within the Barossa can be identified where sufficient variations between vineyard elevations exist that impart grape compositional differences, which in turn translate into wine sensory attributes. Significance of the Study: This empirical study provides some evidence for regionality within the Barossa with up to three subregions identified in some vintages. [ABSTRACT FROM AUTHOR]

Author(s): Paul K. Boss [1]; Mark R. Thomas (corresponding author) The transition from vegetative to reproductive growth is an essential process in the life cycle of plants. Plant floral induction [...]

Abstract Background The composition of grapevine berry at harvest is a major determinant of wine quality. Optimal oenological maturity of berries is characterized by a high sugar/acidity ratio, high anthocyanin content in the skin, and low astringency. However, harvest time is still mostly determined empirically, based on crude biochemical composition and berry tasting. In this context, it is interesting to identify genes that are expressed/repressed specifically at the late stages of ripening and which may be used as indicators of maturity. Results Whole bunches and berries sorted by density were collected in vineyard on Chardonnay (white cultivar) grapevines for two consecutive years at three stages of ripening (7-days before harvest (TH-7), harvest (TH), and 10-days after harvest (TH+10)). Microvinification and sensory analysis indicate that the quality of the wines made from the whole bunches collected at TH-7, TH and TH+10 differed, TH providing the highest quality wines. In parallel, gene expression was studied with Qiagen/Operon microarrays using two types of samples, i.e. whole bunches and berries sorted by density. Only 12 genes were consistently up- or down-regulated in whole bunches and density sorted berries for the two years studied in Chardonnay. 52 genes were differentially expressed between the TH-7 and TH samples. In order to determine whether these genes followed a similar pattern of expression during the late stages of berry ripening in a red cultivar, nine genes were selected for RT-PCR analysis with Cabernet Sauvignon grown under two different temperature regimes affecting the precocity of ripening. The expression profiles and their relationship to ripening were confirmed in Cabernet Sauvignon for seven genes, encoding a carotenoid cleavage dioxygenase, a galactinol synthase, a late embryogenesis abundant protein, a dirigent-like protein, a histidine kinase receptor, a valencene synthase and a putative S-adenosyl-L-methionine:salicylic acid carboxyl methyltransferase. Conclusions This set of up- and down-regulated genes characterize the late stages of berry ripening in the two cultivars studied, and are indirectly linked to wine quality. They might be used directly or indirectly to design immunological, biochemical or molecular tools aimed at the determination of optimal ripening in these cultivars.