Transfer of Blue Mold Resistance into F1 Tobacco Hybrids1
- C. E. Dean,
- H. E. Heggestad and
- J. J. Grosso2
Seventeen F1 hybrids resulting from crosses between tobacco (Nicotiana tabacum L.) breeding lines and varieties having different levels of blue mold (Peronospora tabacina Adam) resistance were evaluated. The parental lines were also evaluated to provide a basis for rating the hybrids. The resistance of the F1 hybrids and parental lines was determined both at the seedling stage in greenhouses and at a more mature growth stage in the field.
Seventy-two percent of the F1 hybrids were intermediate between the parental lines in terms of resistance classification. Those outside the parental limits were always slightly more susceptible rather than more resistant than the parents.
Differences in the effectiveness of lines in imparting resistance in an F1 hybrid were demonstrated. These differences were postulated to be caused by a more complementary genetic constitution containing modifiers which interact favorably with the major blue mold resistance genes. 'Dixie Shade' was a more desirable parent than was 2238.
Blue mold resistance at an effective field level can be utilized in F1 hybrids provided that careful selection of parental lines for resistance and other characteristics is practiced. Hybrids from crosses of resistant and susceptible parents should have a level of resistance sufficient for average field conditions.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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