Developing a model system to identify the main mechanisms involved in nitrogen growth responses of grafted grapevines

In grafted grapevines, the growth potential (vigor) of the scion results from the three-way interaction between the environment, the scion genotype, and the rootstock genotype.
Since nitrogen (N) availability is a major driver of grapevine growth, understanding N metabolism regulation by both grafted partners could lead to the development of new practices aimed at controlling plant vigor.
We are developing a model system to study N regulation by evaluating the responses to N supply among six scion/rootstock (S/R) combinations with known differences in vigor for both partners.
The primary objective is to understand the influence of scion and rootstock separately on growth parameters and resource allocation.
We measured stem growth during two seasons and biomass, carbon (C) and N allocation patterns in tissues (leaves, stem, trunk and roots) of four plants at the end of the first season.
Preliminary results supported the expected vigor behavior of the three ‘Pinot noir’ scions grafted to the same rootstock.
This was not true for the four rootstocks grafted to the same scion.
High N treatment increases C and N allocation in perennial plant parts.
During the second year, N-starvation treatment of the same plants revealed differences in the capacity of rootstocks to remobilize reserves to sustain scion growth.
This experiment is the first step in a broad range project that will evaluate the interaction response of scions and rootstocks to N supply.

XII International Conference on Grapevine Breeding and Genetics

L. Rossdeutsch, P. Schreiner, P. Skinkis, L.G. Deluc

‘Pinot noir’, clonal variability, rootstock, resource allocation, mass allocation, C/N reserves

https://doi.org/10.17660/ActaHortic.2019.1248.52