VIEW ARTICLE

Resistance

New Races 5 and 6 of Phytophthora megasperma var. sojae and Differential Reactions of Soybean Cultivars for Races 1 to 6. Jerry H. Haas, Plant Pathologist, Agriculture Canada, Research Station, Harrow, Ontario, N0R 1G0, Canada, Present address: Department of Plant Pathology, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel; R. I. Buzzell, Soybean Breeder, Agriculture Canada, Research Station, Harrow, Ontario, N0R 1G0, Canada. Phytopathology 66:1361-1362. Accepted for publication 17 May 1976. Copyright © 1976 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-66-1361.

Soybean (Glycine max) hypocotyl-inoculation tests for vertical resistance were used to differentiate two new pathotypes of Phytophthora megasperma var. sojae that were different from races 1 to 4 and are proposed as races 5 and 6. Eight different soybean resistance-susceptibility combinations were identified from differential cultivar responses to the six races.