VIEW ARTICLE
Research Inheritance of Partial Resistance to Black Root Rot in Burley Tobacco. C.
A. Wilkinson, Assistant Professor, Southern Piedmont Agricultural Experiment
Station, Virginia Polytechnic Institute and State University, Blackstone 23824;
R. C. Rufty, Associate Professor, Department of Crop Science,
Box 7620, and H. D. Shew, Associate Professor, Department of Plant Pathology, Box 7616,
North Carolina State University, Raleigh 27695. Plant Dis. 75:889-892. Accepted
for publication 11 March 1991. Copyright 1991 The American Phytopathological
Society. DOI: 10.1094/PD-75-0889. Two generation mean analyses were used to assess the inheritance of partial
resistance to black root rot in burley tobacco. A cultivar moderately resistant
to black root rot, KY 14, was crossed with a cultivar with low resistance,
Burley 21, and with a susceptible cultivar, Judy’s Pride. Five-week-old
seedlings of the parental, F1, F2, and both backcross
generations for each cross were transplanted into soil infested with 100
chlamydospores of Thielaviopsis basicola per gram of soil mixture and
grown in the greenhouse at 21 C. Percent root necrosis was estimated 3 wk after
transplanting. Dominance gene effects were significant and negative in the KY 14
× Burley 21 cross, whereas additive gene effects were significant in the KY 14 ×
Judy’s Pride cross. Epistatic effects were significant in both crosses.
Transgressive segregants were identified that may be used in a recurrent
selection program to increase levels of resistance to black root rot in burley
tobacco. |