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Abstract :

In the context of climate change, with an increase of temperature and a rarefaction of rainfall, the sustainability of grapevine is threatened. Genetic diversity is a potential lever to identify alleles involved in adaptation to abiotic constraints and in turn better adapted varieties. My PhD project aims at understanding the genetic variability and determinism of hydric and carbon functioning at the leaf level in response to water deficit. A diversity panel of 250 genotypes was studied under three hydric condition (Well-Watered, Moderate Water Deficit, Severate Water Deficit) in the PhenoARCH platform in 2022 in order to evaluate the response of grapevine to water deficit for multiple traits. Some were simple to acquire such as SPAD data (correlated with chlorophyll content), Water Content (WC) and Leaf Mass Area (LMA). Looking at the row data distributions, we can already see variability for these traits and a difference between water conditions. Other traits are destructive or take time to phenotype. To tackle this issue, a subset of 120 plants was chosen to be phenotyped with low throughput devices while the entire panel was phenotyped at high-throughput using NIRs (Near-InfraRed spectroscopy) and a porometer/fluorometer. Prediction models will be built to predict the traits of interest on the whole panel, and study their genetic variability in response to the water scenario applied. The genetic analysis will involve an association study between genotype and phenotype to identify QTLs (Quantitative Traits Loci) involved in water and carbon functioning. The identification of extreme alleles will further be studied in the vineyard in order to validate their effect and potential for grapevine adaptation to water deficit.

Keywords: genome-wide association genetics, ecophysiology, water deficit, high-throughput phenotyping, grapevine