Abstract
The excised pistil technique was used to study effects of pollen treatments on self-incompatibility in red clover. Pollen was treated directly with infrared or ultraviolet radiation, and indirectly with chemicals that were applied to the stigmas before pollination. The chemicals (boric acid, calcium nitrate, colchicine, cyclohexamide, gibberellic acid, glycine, and indole butyric acid) were each used at five concentrations. High dosage rates of most treatments inhibited pollen growth in styles that were genetically compatible, but none of the treatments had a specific effect on the self-incompatibility mechanism.