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Pruning strategy and Shoot Counts at Clayton

by Tim Martinson

When we pruned our Marquette and Frontenac training system trial at Clayton in April, we knew there was the potential for winter injury.  So we left extra buds, in the hopes that the extra buds would compensate for bud injury.  Here’s how that worked out:

1.  Frontenac.   We left extra long spurs, 6-9 buds long in the Top Wire Cordon (TWC) and Vertical Shoot Positioned (VSP) plots, and extra canes in the cane-pruned Umbrella Kniffen plots (example in photo below). Front few shoots-suckers

How well did that work?  Table below shows total nodes (the number of ‘count buds’ we left) and total shoots (number of shoots that pushed), and the adjusted shoot number (number of shoots per vine after shoot thinning in late May) in both 2013 and 2014.

Note that in 2013 we left around 48-50 buds per vine, while in 2014 we left 76-90 buds (larger number on cane-pruned UK). Almost double the number of retained buds.   Out of those buds we got 52-58 shoots in 2013, and 40-55 shoots in 2014.  So by this measure, the compensation ‘worked’.  We then thinned shoots (both years) down to a target of 35-40 shoots per vine (7 ft spacing).

Note that the ‘shoots per retained node’  declined from about 1.2 in 2013 to 0.5-0.7 in 2014.

 2. Marquette:  We left slightly more nodes in the Marquette in 2014 (77-81) than in the frontenac,  but ended up with a similar number of shoots – except for in the VSP treatment (33 shoots/vine.).  Again in 2013 we had 1-1.1 shoots per retained node, while in 2014 we had 0.4-0.7 shoots/node.  After adjustment, we came up with more shoots per vine in 2014 (except for VSP).

Bottom line: By leaving extra buds, we were able to end up with about the same shoot number as last year.  The next question:  How much fruit are those shoots carrying, compared to 2013?  Answer (see next post):  Not nearly as much.


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