In a lot of the viticulture guidelines and literature about shoot thinning we differentiate between count and non-count shoots. Before we get into why this matters, let’s differentiate them.
Count shoots are the shoots that arise from a node that we counted at pruning time. So if we left 50 buds, the 50 shoots that in theory arise from them are considered count shoots. Non-count shoots are shoots that come from places that we did not count at pruning.
The photo below shows the count shoots coming off of canes and the non-count coming off of older wood.
Typically it is thought that these non-count shoots have inferior quality fruit than count shoots. For this reason they are often thinned off unless they are growing in blind spots where renewal is needed.
There has not been a lot of work done with the differences in the fruit from count and non-count shoots. The only published work I found was by Wolpert, Howell and Mansfield in 1985 with Vidal (Am. J. Enol. Vitic., Vol. 34, No. 2, 1983). In this study they defined count shoots as those originating more than about a inch from the base of a cane and non-count as anything else.
What they found was that count shoots had about 60% larger clusters, ~5% higher soluble solids and a ~10% lower TA. This is generally what we might expect. The question remains is it the origin that determines the differences in ripening, or is it when they begin to grow?
If we look in the above photo we can see that the lower right non-count shoot looks to be very similar to the count shoots in age. However, the lower non-count shoot in the center of the photo is quite a bit behind in development. It makes sense that the latter would be behind in ripening compared to the count shoots, but what about the non-count that is the same age as the count? I don’t know, but my tendency is to put the emphasis on the age of the shoot (or when it started growing) rather than where it originates.