Petiole phosphorus concentration is controlled by the rootstock genetic background in grapevine: is this a key for understanding rootstock conferred vigour?

Abstract

Context and purpose of the study – Grapevine, Vitis vinifera, requires grafting on Phylloxera tolerant rootstocks of American origin in most viticultural areas of the world. The most commonly used species in rootstock creation are V. berlandieri, V. riparia and V. rupestris. Rootstocks not only provide tolerance to Phylloxera but assure the supply of water and mineral nutrients to the scion. The objective of this work was to determine to what extent rootstocks of different parentages alter the mineral composition of petioles of grapevine.

Material and methods – Vitis vinifera cv. Cabernet Sauvignon clone 169 was grafted onto 13 rootstock genotypes and planted in 2015 in an experimental plot named GreffAdapt. The rootstocks were: Riparia Gloire de Montpellier, 101-14MGt, 3309C, 420A, SO4, 44-53M, Gravesac, Freedom, Dog Ridge, 41B, Rupestris du Lot, 1103P et 110R. The concentration of the following 13 mineral elements was determined in the petioles at veraison (berry softening, 14/08/2017): Nitrogen, Phosphorus, Potassium, Sulphur, Magnesium, Calcium, Sodium, Bore, Zinc, Manganese, Iron, Cupper and Aluminium. Four petioles were harvested from near the clusters from 2 plants for each block (n = 4 per rootstock genotype) and were dried (in an oven at 60°C until they reached a constant mass). Nitrogen content was determined using a Leco FP-528 instrument (LECO, St. Joseph, MI, USA). Other element contents were determined by digesting the plant sample with nitric acid and hydrochloric acid in a CEM Mars5 microwave digester (CEM, Matthews, NC, USA), elemental concentration was determined by reading the solutions on an ICP-OES MS 730-ES (Varian, Palo Alto, CA, USA). Cane pruning weight was also measured for each vine.

Results – The parentage of rootstocks has a significant effect on petiole mineral composition. Rootstocks with at least one V. riparia parent reduced the concentration of P and increased the concentration of Mg and S in the petiole of Cabernet Sauvignon.

Conclusions – Rootstocks with a V. riparia parent generally confer low scion vigour and we have shown that they also confer low petiole P concentration; this could suggest that P uptake and use is related to rootstock conferred vigour in grapevine. These results will be discussed in the context of previous work we have undertaken to understand the genetic architecture of root growth traits in grapevine. This is the first study to demonstrate a significant link between the genetic origin of a rootstock genotype and its ability to regulation scion P content.