Genetic Determination of Vegetative Vigor in a Ramsey × Riparia GM Population

INÉS HUGALDE; SUMMAIRA RIAZ; CECILIA B. AGÜERO; MARCOS PAOLINELLI; NINA ROMERO; ANDY VIET NGUYEN; HERNÁN VILA; SEBASTIÁN GOMEZ TALQUENCA; ANDREW WALKER

Napa

Conferencia; 70th ASEV National Conference; 2019

Univeristy of California

Vigor control achieved by grafting with rootstocks is essential for viticulture, especially in the context of climate change. We studied F1 progeny from a cross between Ramsey and Riparia Gloire de Montpellier, rootstocks that confer high and low vigor, respectively. We hypothesized that vigor, defined as canopy biomass, correlates with growth rate, leaf area, biomass partitioning, and plant hydraulics, and that these variables could be associated with genomic regions. Multiple replicates of 138 F1 seedling plants were evaluated for 60 days in a greenhouse at the University of California, Davis, in 2014 and 2015. Each plant was pruned to a single shoot and watered daily. Shoot growth rate, leaf area, and dry biomass were measured for the complete population, while plant and root hydraulic conductance, stomatal conductance, and water potential were measured for a subset of 50 genotypes. Principle component analysis showed a strong role for shoot growth rate, specific leaf area, plant hydraulics, and partitioning indices for vigor determination. Significant QTLs for leaf area, specific leaf area, and partitioning indices were found on multiple chromosomes. Genes located ~700 kb from each QTL mapping position (350 genes) were interrogated for functional enrichment through the PANTHER online tool, based on the annotation information of the Vitis vinifera PN40024 gene ontology. Using a p-value threshold of 0.05 in a binomial test, key biological processes like photosynthesis, leaf development, light and radiation response, cell plasma membrane, cell wall assembly, sugar metabolism, and nitrogen compounds showed functional enrichment, reinforcing the importance of the QTLs here identified as genetic markers of vigor.