Influence of retained node number on Sauvignon Blanc grapevine phenology in a cool climate

Abstract

Background and Aims In Marlborough's cool climate, slow ripening grapes often do not reach ripeness. This study determined the effect of crop load, achieved via different levels of retained node number, on Sauvignon Blanc phenology and ripening. Methods and Results Two to six canes, each single cane unit having 12 nodes, were laid down and from these vines phenological development was recorded and growth curves were calculated for budburst, flowering, veraison and ripening over 4 years, from 2007 to 2010. The different crop loads, obtained through these pruning treatments, had little influence on vine phenology until after veraison when the retained node number had a significant influence on the rate of accumulation of total soluble solids during the ripening period. Target ripeness was delayed by up to 41 days when 72 nodes were retained, compared with 24 nodes. Simple modelling with generalised logistic functions accurately described phenological changes in the plant and improved the reliability of statistical comparison of time courses between the different treatments. Conclusion For all 4 years of the study, differences in retained nodes per vine had little influence on the phenology of the vine up to veraison, but had a strong effect on the rate of ripening because of subsequent differences in crop load. After the first year of the trial, the influence of the retained nodes on yield gradually diminished and as a consequence so did the influence on the rate of ripening. Significance of the Study A clear demonstration of the strong influence of crop load on the rate of ripening of Marlborough Sauvignon Blanc, together with the capacity of the vines to adjust their source/sink balance over time, with the direction of the adjustment determined by the node number.

Effect of Postharvest Defoliation on Carbon and Nitrogen Resources of High-Yielding Sauvignon blanc Grapevines

“…It is therefore essential to avoid yields above which a target Brix maturity value (measuring the TSS content) is unlikely to be achieved (Greven et al 2015). In 2009, as a consequence of the greater productivity of the 72-node vines, there was a small delay in fruit reaching the targeted maturity, evident from the significantly lower TSS at harvest.…”

“…Loss of photosynthetically active leaf area or excessive crop loads may deplete storage reserves (Candolfi-Vasconcelos et al 1994b). High crop loads may reduce the amount of accumulated vine reserves before harvest and the delayed fruit maturation may shorten the postharvest period (Greven et al 2015). These effects reduce the vine's capacity to accumulate CHO for the following season.…”

Efeito da carga de gemas da videira ‘Cabernet Franc’ na interceptação da radiação solar e na fertilidade de gemas

“…Pesquisas pioneiras realizadas na Nova Zelândia por JACKSON & LOMBARD (1993) descreveram que o número de gemas variando de 40 a 150 por plantas, em cinco cultivares, incluindo a Sauvignon Blanc, apresenta um comportamento curvilíneo, onde o aumento de 43 para 86 gemas por planta dobrou a produção, no entanto, ao aumentar o número de gemas para 150 por planta, o aumento da produção foi de apenas 12% em relação a 86 gemas por planta. Conforme trabalho realizado por GREVEN et al (2015), o aumento de 24 para 72 gemas por planta resultou em aumento da produtividade de 4,8 para 12,7 ton/ha. No entanto, deve ser considerado ainda que o manejo da copa em função do tipo e intensidade da poda exerce efeito sobre a produção no ciclo seguinte, devido ao seu impacto sobre o conteúdo de reserva acumulado e à fertilidade das gemas (VASCONCELOS et al 2009, PELLEGRINO et al 2014.…”

Fenologia e maturação da videira ‘Cabernet Franc’ em função de diferentes cargas de gemas em região de elevada altitude de Santa Catarina

“…Há algumas evidências que a poda com maior número de gemas pode atrasar a floração e diminuir a taxa de floração (DIXON 2009). Já em estudo realizado por GREVEN et al (2015), também realizado Nova Zelândia, com a e mesma variedade, observou-se que o aumento da carga de gemas não apresentou efeito na duração de cada estádio fenológica da videira (brotação, floração e verásion).…”