The Genetic Architecture of Grapevine Leaf Morphology

The vast complexity of plant leaf shape and form add beauty to the world around us.  However, leaf shape also plays important roles in water use, canopy structure, and physiological tolerances to abiotic stresses.  All of these traits are important for the future development and sustainability of grapevine cultivation.  Ampelography, the study of leaf shape in grapes, has been used historically to differentiate Vitis species and cultivars based on finite leaf attributes.  However, these individual measurements do not comprehensively illustrate the entirety of leaf shape.  We paired a seventeen-point landmark survey with a Generalized Procrustes Analysis (GPA) to reconstruct grapevine leaves digitally from five interspecific hybrid mapping families.  Using the reconstructed leaves, we identified significant shape variation via Principal Components Analysis (PCA).   Next, we performed Quantitative Trait Loci (QTL) analyses by integrating the PCA dataset with high-resolution linkage maps of each family to determine the underlying genetic architecture that defines leaf shape.  We plan to develop molecular markers based on the results for marker-assisted breeding of leaf morphology and to provide a genetic-based tool to differentiate Vitis species.