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Cytology and Histology

Histopathology of Soybean Seeds Infected with Alternaria alternata. Indra K. Kunwar, Visiting research associate, Department of Plant Pathology, University of Illinois at Urbana-Champaign (UIUC), Urbana 61801; J. B. Manandhar(2), and J. B. Sinclair(3). (2)(3)Graduate research assistant, and professor, respectively, Department of Plant Pathology, University of Illinois at Urbana-Champaign (UIUC), Urbana 61801. Phytopathology 76:543-546. Accepted for publication 13 January 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/Phyto-76-543.

Mature and immature soybean (Glycine max) seeds infected with Alternaria alternata were small and shrunken with light to dark brown lesions. The fungus was recovered from 100% of surface-sterilized seeds exhibiting symptoms. Hyphae and conidia of A. alternata were concentrated near the hilum region on the surface of seed coats of infected seeds. In histopathological studies, hyphae of the fungus were observed in all layers of the seed coat and endosperm. In moderately to heavily infected seeds, hyphal mats obliterated the endodermis and endosperm. A brown discoloration was observed in unstained seed coat, endosperm, and cotyledonary tissues of moderately to heavily infected seeds.