Grapevine rootstocks affect growth-related scion phenotypes

Abstract

19Grape growers use rootstocks to provide protection against pests and pathogens and to modulate 20 viticulture performance such as shoot growth. Our study examined two grapevine varieties 21 ('Chardonnay' and 'Cabernet Sauvignon') grafted to 15 different rootstocks and determined the 22 effect of rootstocks on eight traits important to viticulture. We assessed the vines across five 23 years and identified both year and variety as contributing strongly to trait variation. However, the 24 effect of rootstock was relatively consistent across years and varieties, explaining between 9% 25 and 10% of the variation in growth-related traits including yield, pruning weight, berry weight, 26 and Ravaz index (yield to pruning weight ratio). Increases in yield due to rootstock were 27 generally the result of increases in berry weight, likely due to increased water uptake by vines 28 grafted to a particular rootstock. We determined that it is possible to achieve an over 50% 29 increase in yield, pruning weight, and Ravaz index by choosing the optimal rootstock, indicating 30 that rootstock choice is crucial for grape growers looking to improve vine performance. 31 32 157 158

Rootstock‐conferred traits affect the water use efficiency of fruit production in Shiraz

“…Nevertheless, a broad relationship between rootstock conferred vigour and vine yield might be expected, and indeed, Jones et al (2009) found a strong correlation between the two across 60 rootstocks with Shiraz as the scion. In contrast, Migicovsky et al (2021) found no correlation across 30 rootstock : scion combinations, although the vines in that study were shoot thinned and underwent leaf removal in the fruiting zone.…”

X-ray imaging of 30 year old wine grape wood reveals cumulative impacts of rootstocks on scion secondary growth and harvest index

“…Vegetative growth can indicate water availability (Tyree & Ewers, 1991; Munitz et al , 2017), and from this perspective it is not surprising that some of the most correlated traits with rootstock-induced changes in scion trunk radii are related to growth ( Figures 3-5 ). Indeed, a previous study of this vineyard suggested that the 1998 reduction in yield observed may be due to a dry 1997 dormant season (Migicovsky et al , 2021). The cumulative precipitation for 1997 was 2,533 inches.…”

“…A complete history of the vineyard sampled in this study is available in Migicovsky et al (2021), reprinted here for convenience. In 1991 rootstocks were planted near Lodi in San Joaquin County, California, before scionwood was whip-grafted to the planted rootstock in 1992.…”

“…Historical data across 8 traits and all 15 rootstocks were collected for 5 years, from 1995 to 1999, and described in Migicovsky et al (2021). These traits were: soluble solids content, titratable acidity, pH, berry weight, cluster number, yield, pruning weight, and Razav index (a measurement of crop load calculated by dividing yield by pruning weight from the following dormant season).…”

“…However, in some cases, a Ravaz index may be too high, indicating that the vine is overcropped and often resulting in reduced fruit quality and reduced vine size (Bravdo et al , 1984). Grapevine rootstocks modulate both components of Ravaz index, yield and vigor (McCarthy & Cirami, 1990; Ezzahouani & Williams, 1995; Jones et al , 2009; Migicovsky et al , 2021). Water and nutrient uptake are two of the principal means by which rootstocks affect reproductive and vegetative growth, consequently also influencing berry composition (Keller, 2020).…”