Effect of Fall or Spring Infection and Sources of Tolerance of Barley Yellow Dwarf of Winter Wheat1

Authors:
  • GCG. Cisar
    G. Cisar
  • CBC. M Brown
    C. M Brown
  • HJH. Jedlinski
    H. Jedlinski
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Abstract
Seventeen hundred‐twenty selections of winter wheat (Triticurn aestivum L. em Thell.) were screened for tolerance to the barley yellow dwarf virus (BYDV), and the effects of fall and spring BYDV infections on several traits were investigated in different years. Fall infection was more damaging than spring infection for all traits measured except kernel weight and harvest index where spring infection caused more severe reductions. Grain yield was reduced an average of 63% for fall, and 41% for spring infections. No outstanding sources of tolerance were discovered, though some entries were more tolerant than others. Several alloplold derivatives from crosses of winter wheat with tall wheatgrass [Agropyron elongatum (Host) Beauv.] were highly tolerant. A significant interaction of selections with date of inoculation indicated differential response of some entries to fall and spring infections. Some selections were tolerant regardless of the time of infection. The relationship between visual disease severity ratings and plant damage as measured by yield of infected plots as percentage of control plots was sufficiently strong (r = 0.65) to ensure genetic advance toward reduced yield loss by selection based on visual assessment of disease severity.