Influencia da Cultivar e do Ambiente na Maturacao da Uva e na Produtividade da Videira (Vitis vinifera L.)

The aim of the present research is the study of genetics and environmental factors on yield and quality of Vitis vinifera L.. The influence of grapevine and rootstock varieties and their interactions over grapevine productivity and ripening, were studied in an experiment, settled at Dois Portos (Portugal). The results showed that grapevine variety and the year factors have a more important influence comparing to rootstock factor. This search points out to the high genetic potential and ability of adaptation of 'Periquita' cv., that permits to obtain a higher yield without quality losses. Concerning to the rootstocks, the 140 Ru presents a good vigor, high yield and quality independent of the grapevine grafted over it and showed the major adaptation ability to water stress conditions. An elevated correlation factor predawn leaf water potential and photosynthetic rates measured by daily course, was also verified. The comparative study of different 'Periquita' clones shows the existence of important genetic and sanitary variability. The grapevine 'Vital' presents in water stress conditions, an important decrease of yield and vigor, as also a slower storage of sugar in the berries. The acid-base balance of must, namely pH, is strongly influenced by malic acid/K ratioAvailable from Fundacao para a Ciencia e a Tecnologia, Servico de Informacao e Documentacao, Av. D. Carlos I, 126, 1200 Lisboa / FCT - Fundação para o Ciência e a TecnologiaSIGLEPTPortuga