Chapter 1

Annual Growth Cycle of the Grapevine

Flower Cluster Initiation

As the shoot grows the formation of uncommitted primordia takes place within the compound buds (which are not dormant at this early developmental stage) in the leaf axils of the current seasonís shoots. The primordia are described as uncommitted at this point because they can develop into either flower clusters or tendrils, depending on environmental and growing conditions. In other words, bud fruitfulness is determined in the early stages following bud break. At some point during the early part of the growing season the primordia become committed to a flower cluster or a tendril. The period at which flower cluster primordia begin to form on the rudimentary shoot is called flower cluster initiation. Those primordial committed to becoming a flower cluster represent the fruiting potential of the vine for the next season.

Click on the following topics for more information on the annual growth cycle of the grapevine.