Grapevine culture in trenches. 2. Reproductive characteristics and interactions with vegetative growth

Abstract

In order to assess the consequence of a strong vegetative growth on inflorescence development and berry setting, two grapevine cultivars differing in their rate of fruit set were grown for 3 years in a greenhouse under semi-controlled conditions. Merlot (low % fruit set) and Pinot noir (high % fruit set) vines produced well-developed clusters in year 3 after planting, thus allowing the study of interactions between vegetative growth and reproductive development over the third growing season. Progress in development of both cultivars was simultaneous until pea berry size and biomass production was similar throughout the season. However, biomass production was negatively correlated to flower differentiation (number of flowers/inflorescence) in Merlot whereas not in P. noir. Possible causes of this interaction are discussed.