The influence of root restriction, soil texture and lateral growth on vine balance and ripening of Pinot noir

Abstract

Understanding vine balance is essential to develop tools that can potentially assist growers enhance yield without compromising the quality of Pinot noir production. The aim of this research was to examine the effect of pot volume and soil texture on Pinot noir vine balance and berry composition through manipulating the environment in which roots grow (competing sinks). A potted vine model system was set up over two growing seasons where the competing sinks (roots) of Pinot noir were manipulated via pot volume (7.5 L and 4 L pot) and soil texture (0% gravel or 50% gravel) in a controlled environment glasshouse. The influence of laterals as competing source and sinks in combination with root volume was also evaluated. This study showed that increasing pot volume increased the competing sink size of roots in the presence of laterals. However, neither soil texture nor pot volume alterations led to an increase in yield. Moreover, in 50% gravel soil and 4 L volume pots, an increase in vegetative growth occurred, primarily attributed to lateral growth. In the absence of laterals, the competing sinks of roots attained a larger proportion of carbohydrates and therefore responded as a vigorous sink in response to increased pot volume (7.5 L) and potting mix volume (0% gravel). This study demonstrate that vine balance is likely to be modified according to planting density, soil volume and texture, suggesting that in the long term these management aspects may provide tools to adjust the yield-quality seesaw.