September
2002
, Volume
86
, Number
9
Pages
971
-
980
Authors
D. D.
Hoffman
and
B. W.
Diers
,
Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana 61801
;
G. L.
Hartman
,
USDA-ARS and Department of Crop Sciences, University of Illinois
;
C. D.
Nickell
,
Department of Crop Sciences, University of Illinois
;
R. L.
Nelson
,
USDA-ARS and Department of Crop Sciences, University of Illinois
;
W. L.
Pedersen
,
Department of Crop Sciences, University of Illinois
;
E. R.
Cober
,
Eastern Cereal and Oilseed Research Center, Agriculture and Agri-Food Research Canada, Ottawa, Ontario K1A OC6, Canada
;
G. L.
Graef
,
Agronomy Department
, and
J. R.
Steadman
,
Department of Plant Pathology, University of Nebraska, Lincoln 68583
;
C. R.
Grau
,
Plant Pathology Department, University of Wisconsin, Madison 53706
;
B. D.
Nelson
and
L. E.
del Rio
,
Department of Plant Pathology
, and
T.
Helms
,
Department of Plant Sciences, North Dakota State University, Fargo 58105
;
T.
Anderson
and
V.
Poysa
,
Greenhouse and Processing Crops Research Center, Agriculture and Agri-Food Canada, Harrow, Ontario NOR 1G0, CANADA
;
I.
Rajcan
,
Department of Plant Agriculture, University of Guelph, Guelph, Ontario N1G 2W1, Canada
; and
W. C.
Stienstra
,
University of Minnesota, Minneapolis 55108
Affiliations
Go to article:
RelatedArticle
Accepted for publication 7 May 2002.
Abstract
ABSTRACT
Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a major soybean (Glycine max) disease in north-central regions of the United States and throughout the world. Current sources of resistance to Sclerotinia stem rot express partial resistance, and are limited in number within soybean germ plasm. A total of 6,520 maturity group (MG) 0 to IV plant introductions (PIs) were evaluated for Sclerotinia stem rot resistance in the United States and Canada in small plots or in the greenhouse from 1995 to 1997. Selected PIs with the most resistance were evaluated for resistance in the United States and Canada in replicated large plots from 1998 to 2000. The PIs in the MG I to III tests in Urbana, IL were evaluated for agronomic traits from 1998 to 2000. The selected PIs also were evaluated with an excised leaf inoculation and petiole inoculation technique. After the 1995 to 1997 evaluations, all but 68 PIs were eliminated because of their susceptibility to Sclerotinia stem rot. In field tests in Urbana, higher disease severity in selected MG I to III PIs was significantly (P< 0.05) associated with taller plant heights and greater canopy closure. All other agronomic traits evaluated were not associated or were inconsistently associated with disease severity. MG I to III PIs 153.282, 189.931, 196.157, 398.637, 417.201, 423.818, and 561.331 had high levels of resistance and had canopies similar to the resistant checks. The resistance ratings from the petiole inoculation technique had a high and significant (P< 0.01) correlation with disease severity in the MG I and II field tests. The partially resistant PIs identified in this study can be valuable in incorporating Sclerotinia stem rot resistance into elite germ plasm.
JnArticleKeywords
Additional keywords:
disease evaluation,
soybean germ plasm,
soybean resistance,
white mold
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ArticleCopyright
© 2002 The American Phytopathological Society
