VIEW ARTICLE

Ecology and Epidemiology

Seed Mycoflora of Soybeans Relative to Fungal Interactions, Seedling Emergence, and Carry Over of Pathogens to Subsequent Crops. D. C. McGee, Associate professor, Department of Plant Pathology, Seed and Weed Sciences, Iowa State University, Ames 50011; C. L. Brandt(2), and J. S. Burris(3). (2)(3)Technician, and professor, respectively, Department of Plant Pathology, Seed and Weed Sciences, Iowa State University, Ames 50011. Phytopathology 70:615-617. Accepted for publication 29 November 1979. Copyright 1980 The American Phytopathological Society. DOI: 10.1094/Phyto-70-615.

Quantitative estimates were made of fungi frequently found on soybean (Glycine max) seed in 175 seed samples of the cultivars Amsoy, Corsoy, Wayne, and Hodgson grown in Iowa in 1977. The genera studied were Chaetomium, Paecilomyces, Alternaria, Fusarium, Penicillium, Aspergillus, Cladosporium, Cercospora, and Phomopsis. Significant negative correlations were obtained between the amount of seed infected by Cercospora kikuchii and that infected by Phomopsis, Fusarium, or Alternaria, and a significant positive correlation occurred between seed infection by Phomopsis and Fusarium. Phomopsis seed infection was correlated with reduction of seedling emergence in laboratory and field tests. Seed infection by Fusarium was correlated with reduction in laboratory emergence only. No one of the other fungi was associated with reduced laboratory or field emergence. Cultivars did not differ significantly with regard to relationships between fungi on the seed or between seedborne fungi and seedling emergence. Infection levels for C. kikuchii and Phomopsis on planted seed were not correlated with those on seed harvested from these plants. Statistically significant correlation coefficients obtained in the study ranged from 0.3 to 0.6.