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In Vitro Assay for Evaluation of Phytophthora Rot on Soybean Taproots
Author(s) -
Smith M. A. L.,
Wagner R. E.,
Anderson J. S.,
Spomer L. A.
Publication year - 1991
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1991.0011183x003100050057x
Subject(s) - taproot , biology , phytophthora megasperma , cultivar , root rot , phytophthora sojae , lesion , inoculation , phytophthora , botany , horticulture , phycomycetes , pathology , medicine
Root lesions indicate soybean [ Glycine max (L.) Merr.] cultivar resistance to phytophthora rot, caused by the soilborne fungus Phytophthora megasperma Drechs. f. sp. glycinea T. Kuan & D.C. Erwin (Pmg). The type and degree of resistance to Pmg was rapidly, decisively gauged by monitoring lesion expansion and branch root proliferation in a microculture assay. ‘Williams 82’ soybean, containing the resistance gene Rps1‐k exhibited a dark, discrete lesion on taproots within 12 h after inoculation. In the absence of an effective Rps gene, light‐brown water‐soaked lesions on taproots continued to expand with time. Cultivars with different levels of rate‐reducing resistance could be distinguished by measuring lesion size and rate of expansion.