2001 Uniform Regional Scab Nursery for Spring Wheat Parents
 
 
       Coordinators:  David F. Garvin and Robert W. Busch
 (Retired).
                  USDA-ARS, Plant Science Research Unit
                  411 Borlaug Hall, University of Minnesota
                  1991 Upper Buford Circle, St. Paul, MN 55108
        
 
      The  Uniform Regional Scab Nursery was grown for the seventh
 year  in  2001.   Seven locations were included in  the  nursery,
 including  Ames,  Iowa, Brookings, South  Dakota,  St.  Paul  and
 Crookston,  MN,  Prosper and Langdon, ND, and Glenlea,  Manitoba,
 Canada.  Data were obtained from all locations.
      A  total of 45 entries were included in the nursery in 2001.
 This  included the resistant checks 2375, BacUp, and ND2710,  and
 the  susceptible checks Wheaton and Oslo.  The other  40  entries
 were  contributed  by the University of Minnesota,  North  Dakota
 State University, South Dakota State University, Agriculture  and
 Agri-Food  Canada, Western Plant Breeders, and Agripro.   Six  of
 these  40  entries  were  durums, and are  denoted  as  genotypes
 beginning  with  a "D" in the entry list.  Five  other  genotypes
 from South Dakota (PI entries) represent possible new sources  of
 scab resistance were included in the nursery.
      The field data collected at each location varied, but a core
 set  of  traits  evaluated on entries at all  locations  included
 incidence  of  scab  (expressed as  %  infected  heads),  disease
 severity (expressed as % of diseased florets on infected  heads),
 and  disease  index  (incidence  x severity/100).   Additionally,
 several  locations  provided post-harvest  evaluation  data  that
 included   visual  scabby  kernel  ratings  (VSK,  =  tombstone),
 expressed as % kernels in a grain sample (5 locations), and grain
 DON  concentration,  expressed  as  ppm  in  a  grain  sample  (4
 locations).   Other various data were gathered at  the  different
 locations,  and are presented in the individual location  tables.
 A final table reporting overall entry means for parameters across
 locations is included at the end of the report.
      Disease  pressure varied greatly from location to  location.
 Extremely  light  disease  pressure  was  observed  at  the  Ames
 location,  and as such these data were excluded from calculations
 of overall means.  At the other locations, mean disease incidence
 ranged  from  a low of 58.5% for Langdon to a high  of  99.9%  at
 Brookings.  Mean location severities ranged from 8% at Langdon to
 63.3%  at Brookings, while mean disease index ranged from  6%  at
 Langdon, to 63.3% at Brookings.
      Mean VSK ranged from 15.2% at the St. Paul location, to  63%
 at  Brookings.  It should be noted that the nursery locations  in
 Minnesota do not record VSK ratings if they exceed 50%, and  thus
 the  VSK  means at these locations will be biased towards  values
 lower  than  the  true means.  Mean location  DON  concentrations
 ranged from 4.7 ppm at Prosper, to 11.2 ppm at Crookston.
      Correlation  coefficients  were calculated  between  disease
 index,  VSK,  and  DON, using overall means calculated  from  the
 three  locations at which each of these parameters  was  measured
 (St. Paul, Crookston, and Prosper).  The correlations among these
 parameters  were in each instance positive and significant.   The
 correlation between disease index and VSK was 0.79, while disease
 index  and DON exhibited a correlation of 0.66.  Lastly, VSK  and
 DON also exhibited a significant correlation (0.76).
 Cooperators  for  2001 Uniform Regional Scab Nursery  for  Spring
 Wheat Parents