Four years data from California show that Cytokin can be used as a management tool to promote boll set and retention to increase cotton yields. Treatment of cotton with 8 oz Cytokin per acre at first bloom and again two weeks later provided significant increases in mature bolls at the first and second fruiting position on the fruiting branch and also increased total boll set. Total mature bolls were increased by 21 percent, first position bolls increased by 21 percent and yields were increased by an average of 32 percent. Cytokin treated plots matured earlier. (1)