pnut pnut Peanut Science 0095-3679 0095-3679 American Peanut Research and Education Society 10.3146/i0095-3679-2-1-6 Articles Differences in Plant and Pod Reaction of Peanut Lines to Infection by Diplodia gossypina1 D. M. Porter and R. O. Hammons 2 Plant Pathologist and Research Geneticist, respectively, ARS, USDA, Tidewater Research and Continuing Education Center, Holland Station, Suffolk, Va 23437 and Georgia Coastal Plain Experiment Station, Tifton, Ga. 31794

1Cooperative investigations of the Agricultural Research Service, U. S. Department of Agriculture, and The Research Division, Virginia Polytechnic Institute and State University. Contribution No. 285, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061.

 1 1975 1 1975 2 1 23 25 American Peanut Research and Education Society 1975 American Peanut Research and Education Society Abstract

In greenhouse inoculation tests we screened peanut (Arachis hypogaea) cultivars Florigiant and Florispan Runner and breeding lines Tifton 8, F393–9–5–1–2–3, F420–100 and F334A-B-14 for resistance to Diplodia gossypina, using a low and a high level of inoculum. Thirty days after inoculation at the low inoculum level, all of the F393–9–5–1–2–3 and 50% of the Florigiant plants were infected. Thirty days after inoculation at the high inoculum level, all plants of F393–9–5–1–2–3, F420–100, Florigiant, and Tifton 8 were infected. Sixty days after inoculation, 50% of the Florispan Runner plants were infected. Ninety days after inoculation, 60% and 35% of Florispan Runner and F334A-B-14 plants, respectively, were infected. Pods of F393–9–5–1–2–3, F420–100, Tifton 8, and Florigiant were severely rotted 30 days after inoculation. During this time, only 3% of the Florispan Runner pods were rotted, whereas pods of F334A-B-14 remained free of rot. D. gossypina was isolated from all seed from nonrotted pods of F393–9–5–1–2–3, F420–100, Florigiant, and Tifton 8 after inoculation. Only 10% of Florispan Runner seed yielded isolates of this fungus. D. gossypina was not isolated from F334A-B-14 seed.

 Additional index words Diplodia collar rot; , Arachis hypogaea; , resistance; , soil-borne fungi