Effects of Two Introgressed Disease Resistance Factors on Agronomic Characteristics and Certain Chemical Components in Burley Tobacco1
- M. T. Nielsen,
- P. D. Legg and
- C. C. Litton2
Four burley tobacco (Nicotiana tabacum L.) selections differing for resistance or susceptibility to tobacco mosaic virus (TMV) and wildfire (Pseudomonas tabaci L., Wolf and Foster, Stevens) were developed in each of three genetic backgrounds and later evaluated to determine if introgression of genetic factors for disease resistance affected any of six agronomic characteristics and three chemical components. The selections were derived from crosses between burley tobacco isolines possessing the genetic factors, transferred from N. glutinosa L. and N. longiflora Cav., for resistance to TMV and wildfire, respectively. The four selections, the two isolines, and the original susceptible parent of each of the three families were grown for 2 years at Lexington, KY. Since the selections showing susceptible reactions to both mosaic and wildfire performed essentially the same as the original susceptible cultivars, we concluded that the parental genotypes were recovered and that comparisons of the resistant selections with their corresponding isolines and parental cultivars were valid. Consistent differences between the selections and the original cultivar were noted only in one family, and the majority of those differences favored the selections. The wildfire resistant isoline in one family was significantly different from the selections and the parental cultivar. The effect of the introgressed genetic factors for TMV and wildfire resistance on the traits evaluated depended on genetic background. However, the presence of both TMV and wildfire resistance in one breeding line should be considered no obstacle to the further improvement of most other traits.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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