Sustainable yield management through fruitfulness and bunch architecture manipulation

Abstract

Context and purpose of the study ‐ Vineyards are highly variable and this variation is largely driven by environmental conditions and seasonal variation. For example, warm temperatures and sunny days during bud initiation generally result in high yields in the next season while cold periods during flowering and fruitset can reduce yield. As such, this variation in yield and potentially quality is difficult to predict and therefore manage. Early and more accurate assessments of fruitfulness and bunch architecture may improve these predictions. Vineyard management can be used to manage this variation and limit negative impacts on production. This study summarises research that; (1) investigated different methods for the assessment of bud fertility and bunch architecture and (2) assessed the impact of different management techniques on fruitfulness, bunch architecture and resultant yield.

Material and methods – Vineyard management trials were carried out in South‐eastern Australia during the last 4 years and were performed on Syrah, Cabernet Sauvignon, Semillon, Riesling, Grenache, Tempranillo, Merlot and Sauvignon Blanc. Management strategies investigated include; winter pruning, shoot thinning, shoot leaf removal, and bunch thinning. Bud dissection and image analysis was used to assess bud fertility and the size of inflorescence primordia. Image analysis during the growing season and at harvest was used to assess bunch architecture and bunch volume. Bunch weight and yield were determined at harvest to assess yield performance and validate early predictions.

Results – Bud dissection using image analysis was an effective method for early prediction of fruitfulness and bunch weight (R2=0.79). Similarly, assessing bunch volume at veraison correlated with bunch weight 2 at harvest (R =0.78). Assessment methods used in these studies have the potential to be used commercially for yield prediction and management. Management strategies applied in different experimental trials varied in their impact on both bud fertility and bunch architecture (in the current and future seasons). Not surprisingly, timing, extent of application as well as variety had an impact on the final outcome. Understanding how different vineyard management approaches can manipulate components of yield can help producers to manage their vineyards to desired yield and quality outcomes.