505 Chilean Effort for Improving Fruit Quality in Grapevine: A Genomic Approach to Understanding Seed Formation, Fruit Ripening and Pathogen Response Hugo Peña-Cortés, Alvaro Cuadros, Tomas Fichet, Manuel Pinto and Ingrid Ramírez and Jorge Valdés Alejandro Riquelme Universidad Técnica Universidad de Chile, Santiago Federico Santa María, Valparaíso Chile Chile Danilo González, Enrique González Patricio Hinrichsen, Humberto Prieto and Simón Ruiz and Marlene Rosales Universidad de Talca, Talca Instituto de Investigaciones Agropecuarias Chile Santiago Chile Keywords: Vitis vinifera, ‘Thompson Seedless’, ‘Carménère’, berry development, seedlessness, Botrytis cinerea, ESTs, macroarray analysis Abstract Improving fruit quality is a priority for the Chilean grape industry. A national effort has begun using the genomic approach to study problems related to seed formation, fruit ripening and the vine’s response to Botrytis cinerea infection. Seedless cultivars such as ‘Thompson Seedless’ have embryo abortion at an early stage of berry growth impairing seed formation and subsequently affecting the size of the berry. To obtain berries of commercial size, vineyards are sprayed with gibberellic acid (GA 3 ). The genes and/or biological processes controlling embryo abortion and fruit size, as well as the response of berries to GA 3 applications in this and other cultivars are unknown. On the other hand, wine grape cultivars such as ‘Carménère’ also have problems related to seed formation and berry development. Clusters containing a certain percentage of underdeveloped parthenocarpic berries can negatively affect wine quality. The causes for this are also poorly understood. Finally, berries of both ‘Thompson Seedless’ and ‘Carménère’ are affected by Botrytis cinerea. It appears that ‘Carménère’ is more tolerant to the infection than ‘Thompson Seedless’. The genes and/or biological processes regulating these responses are unknown. We have begun a functional genomics approach towards defining the changes that occur during fruit development in both cultivars. We are in the process of sequencing approximately 100,000 ESTs from flowers and fruits collected at different developmental stages, and either sprayed or not sprayed with GA 3 . The clones and sequence information generated will be used to analyze the global gene expression using macroarray analyses. Related information can be found at the web site of The Grape Functional Genomic Project–Chile (DEGECHIVID) http://www.genomicafrutos.cl. INTRODUCTION Grapevine (Vitis species) is economically the most important fruit crop globally due to both its large planted acreage and the numerous uses of its fruit in producing wine, juice, table grapes, raisins and organic compounds (Aigrain, 1999). Chile has become the main exporter of table grapes in the Southern hemisphere. According to the statistics published by the Food and Agriculture Organization (FAOSTAT-Agriculture) Chilean grape production reached 1,750,000 Mt in 2003. Table grapes accounted for 48% of Chile’s total fruit and vegetables exported during years 2003 to 2004. Similarly, wine exports from Chile are increasing reaching 394 millions L during 2003 (Chilean Association of Wine Producers). To improve grape quality and its products a national effort has been undertaken to study several of the main problems affecting grape Proc. VII th IS on Grapevine Ed. L.E. Williams Acta Hort. 689, ISHS 2005