Morphology, Physiology and Analysis Techniques of Grapevine Bud Fruitfulness: A Review

Abstract

Grapevine reproductive development extends over two growing seasons (vegetative cycles), for the complete formation of inflorescences and clusters. Induction and floral differentiation, the mechanism that leads to the formation of reproductive structures inside dormant buds, is a complex process divided into three well-defined stages (formation of anlagen, inflorescence primordia and flowers). This sequence of stages comprises morphological, biochemical, and physiological events, influenced by a set of environmental and endogenous factors. Inflorescence primordia formation determines the potential number of clusters that will be formed in the following growing season. Thus, during bud dormancy, viticulturists and winemakers can obtain a first yield prediction through the determination of bud fruitfulness. This information allows adjustments to be made to bud load, promoting balanced yield and fruit quality and higher commercial value. The present review describes the morphology and physiology of the formation of inflorescence primordia, as well as discusses the main abiotic and biotic factors involved, including a physiological disorder known as primary bud necrosis. In the same way, we intend to approach the more used techniques of analysis of fruitfulness and its importance for a robust yield forecasting.