Analysis of water consumption of various grapevine cultivars

The efficiency of water use (transpiration ratio) was investigated in various cultivars of grapevine by gravimetric and gasometric methods. Results of gravimetric measurements showed positive correlation between water use efficiency and vigor. Regression lines of the transpiration ratio on the final dry weight differed significantly in their curves and their distance from the coordinate axes. Statistical analysis showed that the quantitative effect of vigor on the water use efficiency was smaller in the cultivar Muscat Hamburg than in Sultanina and Queen of the Vineyards. Covariance analysis showed that Sultanina was a less efficient water user than Queen of the Vineyards for plants with the same vigor. Gasometric methods did not reveal any significant differences between the cultivars, probably due to the elimination of interference and boundary layer resistance effect

Iso-geraniol (3,7-dimethyl-3,6-octadien-1-ol): A novel monoterpene in Vitis vinifera L. cv. Muscat Roy

Isogeraniol (3,7-Dimethyl-3,6-octadien-1-ol): Ein neues Monoterpen bei der Sorte Muscat Roy (Vitis vinifera L.)Der Monoterpengehalt im Most der Neuzüchtung Vitis vinifera L. cv. Muscat Roy und ihrer Elternsorten Muscat Frontignan und Dabuki wurde untersucht. Das Monoterpenprofil von Muscat Roy ist dem von Muscat Frontignan sehr ähnlich. Trotzdem enthält es wesentlich höhere Konzentrationen an Geraniol und α-Terpineol. Im Most von Muscat Roy wurde ein neuer Monoterpenalkohol, 3,7-Dimethyl-3,6-octadien-1-ol (Isogeraniol) identifiziert; im Most der Elternsorten ist jedoch kein Isogeraniol nachweisbar

Intensidades da poda seca e do desbaste de cacho na composição da uva Cabernet Sauvignon.

A pesquisa foi realizada durante quatro anos, num vinhedo de Cabernet Sauvignon (Vitis vinifera L.), em Bento Gonçalves-RS. O objetivo foi determinar o efeito das intensidades da poda seca e do desbaste de cacho em variáveis relacionadas aos componentes de produção da videira e à composição do mosto de uva. Os tratamentos consistiram em dois níveis de poda seca - curta e longa - e quatro de desbaste de cacho (%) - 0; 25; 50 e 75 -; com cinco repetições. O delineamento experimental foi o em blocos casualizados, com os tratamentos em parcelas subdivididas. Os resultados mostram que a poda seca e o desbaste de cacho tiveram efeito altamente significativo na produtividade do vinhedo que, na média dos quatro anos, variou de 10.971 kg/ha ? poda curta, 75% de desbaste ? a 32.819 kg/ha ? poda longa, 0% de desbaste. Houve, também, efeito significativo na produtividade por gema, peso de ramos podados por gema e por hectare, área foliar/peso fresco do fruto e produtividade/peso de ramos podados. Entretanto, o efeito nas variáveis relacionadas a açúcar e acidez do mosto da uva foi pouco expressivo. O componente 1 da análise de componentes principais discriminou o tratamento poda curta a 75% de desbaste de cacho dos tratamentos poda longa-0% de desbaste e poda longa-25% de desbaste

The effects of applied water at various fractions of measured evapotranspiration on reproductive growth and water productivity of Thompson Seedless grapevines

The reproductive growth and water productivity (WPb) of Thompson Seedless grapevines were measured as a function of applied water amounts at various fractions of measured grapevine ETc for a total of eight irrigation treatments. Shoots were harvested numerous times during the growing season to calculate water productivity. Berry weight was maximized at the 0.6–0.8 applied water treatments across years. As applied water amounts increased soluble solids decreased. Berry weight measured at veraison and harvest was a linear function of the mean midday leaf water potential measured between anthesis and veraison and anthesis and harvest, respectively. As applied water amounts increased up to the 0.6–0.8 irrigation treatments there was a significant linear increase in yield. Yields at greater applied water amounts either leveled off or decreased. The reduction in yield on either side of the yearly maximum was due to fewer numbers of clusters per vine. Maximum yield occurred at an ETc ranging from 550 to 700 mm. Yield per unit applied water and WPb increased as applied water decreased. The results from this study demonstrated that Thompson Seedless grapevines can be deficit irrigated, increasing water use efficiency while maximizing yields