Impact of mycorrhizal inoculation of ‘Monastrell’ grapevines grafted onto different conventional vs. newly breed rootstocks 

Context and purpose of the study. Climate changes pose the need to develop new grapevine varieties and rootstocks that are more tolerant to stress and diseases.

Botrytis bunch rot occurrence is the most important limitation for the wine industry in humid environments. The effect of grapevine vegetative growth on bunch rot expression results from direct effects (cluster architecture, nitrogen status among others) and indirect ones (via microclimate). Previous studies of our group showed strong differences in bunch rot incidence between floor management treatments: cover crop (CC) vs weed-free strips under the trellis with herbicide (H). We observed that in some circumstances this reduction in bunch rot incidence occurred without major vine growth differences among treatments. The aim of the present study was to test the general hypothesis that other factors unrelated to grapevine vegetative expression could be more relevant to grapevine susceptibility to bunch rot.

In a context of reducing herbicide use, the most part of French vineyards are developing permanent grass cover crops on inter-rows alleys, while under the row chemical weeding remains the general case. The setting up of a controlled grass cover crop under the vine row could be a complementary alternative to mechanical weeding – which one is very restrictive – interesting from a technical and economical point of view. The present study aimed at assessing agronomic impacts of grass cover crop under the row in different climatic conditions and production objectives.

Successful powdery mildew (PM) infection in plants relies on Mildew Resistance Locus O (MLO) genes, which encode susceptibility factors essential for fungal penetration. In Arabidopsis, loss-of-function mutations in three clade-V MLOs, AtMLO2, 6, and 12 confer complete resistance to PM infection. Since then, efforts are on to discover MLO genes contributing to PM susceptibility in many species to introduce mlo-based PM-resistance. Earlier studies in tomato and grapevine, using the RNAi approach, attributed PM susceptibility to SlMLO1, 5, and 8 and VvMLO3, 13, and 17, respectively indicating likely functional redundancy among MLOs.

The increase in temperature caused by climate change produces an earlier budbreak date that affects the vineyard, which generates a greater risk of damage by spring frosts.