Mgaloblishvili Rpv29 and Rpv31 loci reveal new insights on downy mildew resistance sources in Vitis vinifera

Grape seeds account for around 5% of the weight of the whole grape berry, representing approximately 40%-50% of the solid by-products that the different wine industries generate during the winemaking process.

Pinking of white wine is an undesired change potentially occurring over storage, leading to the turning of color from yellow into salmon-red hue.

Bacillus velezensis and Trichoderma harzianum are relevant microorganisms used in viticulture as biocontrol agents against pathogens of trunk (e.g. Phaeoacremonium minimum), leaves (e.g. Plasmopara viticola) or fruit (e.g. Botrytis cinerea), or as biostimulants, improving the resilience of plants against biotic or abiotic stressors through different direct and non-direct interactions.
In this biotechnological approach, formulation plays a crucial role. Controlling water activity in the product, thus stabilising microbial viability is key to ensuring effective application. We present the benefits of the citrate ester CITROFOL® AI (triethyl citrate) as a novel bio-based carrier liquid in microbial formulations. CITROFOL® AI is safe for humans and the environment, thus offering a promising base for sustainable treatments in viticulture.

Making high quality but affordable Pinot noir (PN) wine is challenging in most terroirs and New Zealand’s (NZ) situation is no exception. To increase the probability of making highly typical PN wines producers choose to grow grapes in cool climates on lower fertility soils while adopting labour intensive practices. Stringent yield targets and higher input costs necessarily mean that PN wine cost is high, and profitability lower, in line-priced varietal wine ranges. To understand the reasons why higher yielding vines are perceived to produce wines of lower quality we have undertaken an extensive study of PN in NZ. Since 2018, we established a network of twelve trial sites in three NZ regions to find individual vines that produced acceptable commercial yields (above 2.5kg per vine) and wines of composition comparable to “Icon” labels. Approximately 20% of 660 grape lots (N = 135) were selected from within a narrow juice Total Soluble Solids (TSS) range and made into single vine wines under controlled conditions. Principal Component Analysis of the vine, berry, juice and wine parameters from three vintages found grape berry mass to be most effective clustering variable. As berry mass category decreased there was a systematic increase in the probability of higher berry red colour and total phenolics with a parallel increase in wine phenolics, changed aroma fraction and decreased juice amino acids. The influence of berry size on wine composition would appear stronger than the individual effects of vintage, region, vineyard or vine yield. Our observations support the hypothesis that it is possible to produce PN wines that fall within an “Icon” benchmark composition range at yields above 2.5kg per vine provided that the Leaf Area:Fruit Weight ratio is above 12cm2 per g, mean berry mass is below 1.2g and juice TSS is above 22°Brix.

One of the limitations of vineyards in warm areas is the loss of wine quality due to higher temperatures during the grape ripening period. In order to adapt the vineyards to these new climatic conditions, a possible solution is to delay the ripening process of the grapes towards periods with milder temperatures, by means of management practices and thus improve the quality of the fruit and the wine produced. The technique of severe shoot pruning (SSP) has proven useful in achieving this objective.