Inheritance of Resistance to Tobacco Cyst Nematode in Flue-Cured Tobacco
- Barbara J. Crowdera,
- Carol A. Wilkinson *a,
- Charles S. Johnsonb and
- Jon D. Eisenbachc
- a Dep. of Crop and Soil Environmental Science, Southern Piedmont Agricultural Research and Extension Center, 2375 Darvills Road, Blackstone, VA 23824
b Dep. of Plant Pathology, Physiology, & Weed Science, Southern Piedmont Agricultural Research and Extension Center, 2375 Darvills Road, Blackstone, VA 23824
c Dep. of Plant Pathology, Physiology, & Weed Science, Virginia Polytechnic Institute and State Univ., 103 Price Hall, Blacksburg, VA 24061
The tobacco cyst nematode [Globodera tabacum solanacearum (Miller and Gray) Behrens] is an important pathogen affecting flue-cured tobacco (Nicotiana tabacum L.) in Virginia and North Carolina and type 32 tobacco in Maryland. The objective of this study was to determine the mode of inheritance of resistance to G. t. solanacearum in the flue-cured tobacco cultivars Coker 371 Gold and Kutsaga 110. Each cultivar was crossed to the susceptible cultivar K 326 and F1 progeny were backcrossed to each parent. Plants from each parent and F1, F2, BC1Ps, and BC1Pr progeny were evaluated for G. t. solanacearum resistance in the greenhouse. Six-week-old transplants were inoculated with 6000 G. t. solanacearum eggs from crushed cysts. Eight weeks after inoculation, a 1-g sample of fibrous root was stained and vermiform, swollen, pyriform, and adult nematodes were counted. The number of cysts and eggs per 400 000 mm3 of soil were counted from each transplant. Generation means analyses were performed. Additive and dominance gene action play an important role in resistance to G. t. solanacearum in Coker 371 Gold and Kutsaga 110. F2 progeny data from the Coker 371 Gold cross fit a 3:1 (resistant:susceptible) segregation ratio and BC1Ps generation data fit a 1:1 segregation ratio, indicating that resistance to G. t. solanacearum is conferred by a single dominant gene. A continuous range of variation was observed among the F2 progeny for the K 326 × Kutsaga 110 cross, indicating resistance in Kutsaga 110 is quantitative. Globodera tabacum solanacearum resistance in Coker 371 Gold and Kutsaga 110 may be derived from different sources.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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