The influence of pruning on the germinability of pollen and the set of berries in Vitis vinifera

Abstract does not appear. First page follows.

In the progress of an investigation at the California Experiment Station of the effect of pruning on capacity, vigor, and bearing of Vinifera grapes,⁽¹²⁾ it was observed that the type of pruning influenced the germinability of the pollen and the setting of the fruit.

So far as I have been able to find, no account of the influence of pruning on the germination of pollen has been published. This is also true with reference to the set of fruit, unless we except the many reports of larger yields resulting from the less severe or so-called “long” pruning in deciduous fruits. In this case, however, the larger yields which accrue from the development of a larger number of fruits may be the result of a larger bloom without any change in the quality of the flower parts, since the less severe pruning leaves a larger number of fruit buds on the tree.

Though there are no printed records of an increase in the set of fruits as a result of the long pruning of deciduous trees, the beneficial effect of blossom thinning on set has been indicated by Miss Bradbury.⁽¹⁾ She reports that during the one season of her tests, 1924, the set of fruits on sour cherry trees was increased from 24 per cent on the unthinned branches to 42 per cent on the branches on which the blossom buds of the spurs were thinned as early as practicable to one blossom to a bud.