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Controlled Pollination in Black Walnut

Controlled pollination of black walnut ( Juglans nigra L.) has been accomplished at Purdue University. Six different bagging materials have been tested over a five year period and of these only "Terylene" and "Pollen Tector" bags have produced seed set. However, low seed yields are a continuing problem. Only 908 controlpollinated seeds have been obtained from 3782 flowers pollinated or 24 percent success. Excessive pollination (i.e., large quantities of pollen per pollination) was found to be detrimental since only 8 percent of flowers receiving large quantities of pollen developed nuts vs. 66 percent for the controls. Pollen dilution might increase seed set in the future. Methods of identifying control-pollinated nuts after they fell from the tree were investigated. Of the five techniques attempted, husk chipping with a pocket knife was superior.

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Author(s): Walter F. Beineke, Charles J. Masters

Publication: Tree Improvement and Genetics - Central States Forest Tree Improvement Conference - 1976