Reaction of Sunflower and Safflower Germ Plasm to Verticillium dahliae. J. M. Klisiewicz, Agricultural Research Science and Education Administration, U.S. Department of Agriculture, Department of Plant Pathology, University of California, Davis 95616. Plant Dis. 65:237-239. . This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1981. DOI: 10.1094/PD-65-237.

Growing sunflower and safflower plants in a medium infested with Verticillium dahliae was an effective inoculation method in growth chamber and greenhouse tests to differentiate resistant and susceptible germ plasm. A V. dahliae isolate from sunflower (ND) induced severe disease in open-pollinated sunflower cultivars and inbred lines except the highly resistant inbred line HA 89. Most cultivars and lines had resistance to an isolate from safflower (T-1) and an isolate from cotton (SS-4). HA 89 was susceptible to T-1. Sunflower oilseed hybrids were highly resistant to T-1 and SS-4, and five hybrids were highly resistant to the sunflower isolate. Severe disease developed in most of the safflower introductions inoculated with SS-4 and T-1. Safflower cultivars and breeding lines were susceptible to SS-4 and ranged from highly susceptible to highly resistant to T-1. Reactions differentiating pathotypes were observed in sunflower and safflower.