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           1998 Uniform Regional Scab Nursery for Spring Wheat Parents
 
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 Robert Busch: Coordinator, USDA-ARS. Plant Science Unit, St. Paul, MN 55108
 Gary Linkert: Department of Agronomy and Plant Genetics, Univ. of Minnesota
 Leanne Matthiesen: Department of Agronomy and Plant Genetics, Univ. of Minnesota
 
 	The Uniform Regional Scab Nursery was grown for the fourth time in 1998 at 6 
 locations including St. Paul and Morris, MN; Langdon and Prosper, ND; Brookings, 
 SD; and Glenlea, Manitoba. All nurseries used were misted and inoculated with 
 Fusarium to obtain infection in the entries.
 
 A total of 33 entries were tested including 4 checks (Pioneer 2375, Wheaton, BacUp 
 and Oslo) and 29 parental lines including 4 durums. Most entries have a Chinese 
 source of resistance (Sumai#3, Ning 8331 or Ning 7840) in their pedigrees except 
 for 4 to 5 lines and the durums.
 
 All entries were planted in single rows or hill-planted with 2 to 4 replicates in 
 each location. Inoculation was conducted by scattering infected kernels and/or by 
 spraying the spikes with macroconidia spore suspension during anthesis (2 X104 to 
 10 X 104 spores/ml). A misting system was used for enhancing the disease infection 
 and spread.
 
 Visual head symptoms of scab infection and post-harvested visual scabby kernel 
 rating (or % Tombstone) based on a standard set were assessed. DON analyses were 
 also conducted. Each location's data are presented separately and entry means were 
 used for the combined location's analysis.
 
 Level of disease varied with locations. Location means for Disease Index or FHI3 
 index ranged from 18.6% at St. Paul to 63.8% at Brookings. Percent tombstone ranged 
 from 6.7% at St. Paul to 58.8% at Brookings. Entry performance varied with 
 locations. Heading date had considerable impact at Morris with earlier heading 
 entries less affected by Fusarium. Correlations among the traits, Disease index, % 
 Tombstone, and DON among the traits and between locations are given in Table 9a. 
 Langdon % Tombstone data were most closely related to Manitoba, and was not well 
 associated with either Morris or St. Paul. Yield from Brookings was well related to 
 % Tombstone from the other locations with St. Paul % Tombstone lowest (r=-0.5) to 
 Brookings % Tombstone highest (r=-0.88). Langdon test weight was related to % 
 Tombstone poorest to St. Paul % Tombstone (r=-0.3) and best to Langdon % Tombstone 
 (r=-0.67).
 
 Correlation among the means over locations indicated that DON, % Tombstone, and 
 Disease Index were highly positive with the lowest association between DON and 
 Disease Index (Table 9b). Severity was not related to any of the other traits, 
 while incidence was related to both DON and % Tombstone. Selection for Disease 
 Index and % Tombstone appear to be providing similar information for resistance. 
 DON was less well related, but this maybe mainly due to only St. Paul and Morris 
 having collected these data. A more northern site may have provided a less biased 
 relationship.