Methyl jasmonate versus nano-methyl jasmonate. Effect on the tannin composition of monastrell grapes and wines

We analyze the effects of climate (temperature and pluviometry) on the phenologic stages of the vine (débourrement, flowering, ripening and grape harvest). We rebuilt time series starting from the beginning of the XIXth century for the Medoc and the area of Bordeaux, data very seldom mobilized by researchers.

To study the copigmentation between different wine flavonols (myricetin, quercetin, kaempferol, isorhamnetin and syringetin 3-O-glucosides) and malvidin

Herbicides are commonly sprayed in the vine row to prevent competition with vines for water and minerals and to keep weeds from growing into the bunch zone. Sprays are applied before budbreak and reapplied multiple times during the season to keep the undervine bare. There is growing concern about the negative effects of herbicides on humans and the environment, and weeds in New Zealand have developed resistance to herbicides. Therefore, it is imperative that we reduce our reliance on herbicides in viticulture and incorporate methods that do not engender resistance.

Changes in bioclimatic indices in wine-growing region of Serbia are analyzed under the RCP 8.5 IPCC scenario.

High concentration of sugars in grapes and alcohol in wines is one of the consequences of climate change on viticulture production in several wine-growing regions. In order to investigate the possibilities of adaptation of vineyard management practices aimed to reduce the accumulation of sugar during the maturation phase without reducing the accumulation of anthocyanins in grapes, a study with severe shoot trimming, shoot thinning, cluster thinning and date of harvest was conducted on Merlot variety in Istria region (Croatia), under the Mediterranean climate. Four factors which may affect grape maturation and its composition at harvest were investigated in a two-years experiment; severe shoot trimming applied at veraison when >80% of berries changed colour (in comparison to untreated control), shoot thinning (0 and 30%), cluster thinning (0 and 30%), and the date of harvest (early and standard harvest dates). Shoot thinning had no significant impact on berry composition, despite the obtained reduction in yield per vine. Lower Brix in grapes were obtained with earlier harvest date and if no cluster thinning was applied, although at the same time a reduction in the concentration of anthocyanins in berries was observed in these treatments. On the other hand, if severe shoot trimming was applied when >80% of berries changed colour, a reduction of Brix was obtained without a negative impact on berry anthocyanins concentration. We conclude that in cases when undesirably high sugar concentrations at harvest are expected, severe shoot trimming at 80% veraison may effectively be used in order to obtain moderate sugar concentration in berries together with the adequate phenolic composition.