The influence of host plant variety on the inoculation of burley tobacco, Nicotiana tabacum (L.), with tobacco vein mottle virus (TVMV) by the tobacco aphid, Myzus nicotianae Blackman, was examined in the laboratory. Burley tobacco varieties 'Burley 21' (B21) and Tennessee 86' (T86) were used as aphid hosts, TVMV inoculum sources, and virus recipients. T86 was less susceptible to infection (mean proportion infected = 0.30) as compared with B21 (mean proportion infected = 0.52). A reduction in the percentage of plants developing TVMV infection was observed when aphids were reared on and acquired virus from one variety and then were transferred to recipient plants of the other variety. This suggests that viruliferous aphids migrating from one tobacco variety to a different variety may not be as effective vectors of TVMV as resident aphids or aphids migrating to similar varieties.

Potato virus Y (PVY), susceptible tobacco (Nicotiana tabacum L.) cultivar, McNair 944, was subjected to in vitro anther culture to determine if genetic variability for virus resistance could be induced among resulting haploids. Five hundred and forty-five haploids were produced and inoculated with a highly necrotic strain (NN) of PVY. One haploid plant survived, even though it was infected with the virus. Selfed progenies of a chromosome-doubled plant of this variant, designated NC 602, proved to be highly resistant to the necrotic effects of the virus. An investigation into the genetic nature of this variant showed the resistance mechanism to be controlled by a single gene exhibiting incomplete dominance. Cytoplasmic and maternal effects were not involved in the disease resistance reaction. The variant was challenged with ten additional strains of PVY from an international collection, and it proved to be resistant to three (VAM-B, MM, and Spanish) strains. NC 602 was evaluated for five agronomic traits and concentrations of total alkaloids as nicotine and reducing sugars in cured leaf. The gametoclonal variant differed from McNair 944 only for cured leaf yield, where an 18.4% reduction was measured.

A previously identified gametoclonal tobacco variant, NC 602, exhibits resistance to certain potato virus Y (PVY) strains. NC 602 was subjected to a second cycle of anther culture and colchicine treatment. The resulting doubled haploid lines were evaluated for back mutation to susceptibility and any additional mutation that might provide resistance to tobacco etch virus (TEV). The PVY resistance was stable in anther culture, and although no TEV resistance was found, three lines were identified with delayed symptom onset. NC 602 was crossed to breeding line NC 744, which contained the PVY resistance gene found in the Virgin A Mutante (VAM) (Tobacco Introduction line 1406). Maternal doubled haploid lines of this cross were screened for both resistance genes by using an array of PVY strains to distinguish genotypes. Results demonstrated that the two genes could be combined into a single genome with improved levels of resistance, thus indicating different loci for each resistance. NC 602 was also crossed to a root-knot nematode (Rk) resistant cultivar (Coker 209) in an effort to combine PVY and Rk resistance for protection against the MN strain of PVY in Rk resistant varieties. Plants were identified at the haploid level, which contained both PVY(NN) and Rk resistance, but when these plants were doubled and challenged with the PVY(MN) strain, all lines resistant to Rk showed susceptibility to the virus.

Crop ScienceVolume 30, Issue 1 cropsci1990.0011183X003000010071x p. 241-242 Registration of Germplasms Registration of NC-BMR 42 and NC-BMR 90 Germplasm Lines of Tobacco R. C. Rufty, Corresponding Author R. C. Rufty n/[email protected] Dep. of Crop ScienceCorresponding author.Search for more papers by this authorE. A. Wernsman, E. A. Wernsman Dep. of Crop ScienceSearch for more papers by this authorC. E. Main, C. E. Main Dep. of Crop ScienceSearch for more papers by this authorG. V. Gooding Jr., G. V. Gooding Jr. Dep. of Plant Pathology, North Carolina State University, Raleigh, NC, 27695Search for more papers by this author R. C. Rufty, Corresponding Author R. C. Rufty n/[email protected] Dep. of Crop ScienceCorresponding author.Search for more papers by this authorE. A. Wernsman, E. A. Wernsman Dep. of Crop ScienceSearch for more papers by this authorC. E. Main, C. E. Main Dep. of Crop ScienceSearch for more papers by this authorG. V. Gooding Jr., G. V. Gooding Jr. Dep. of Plant Pathology, North Carolina State University, Raleigh, NC, 27695Search for more papers by this author First published: 01 January 1990 https://doi.org/10.2135/cropsci1990.0011183X003000010071xCitations: 5AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article.Citing Literature Volume30, Issue1January–February 1990Pages 241-242 RelatedInformation

Rufty, R. C., Wernsman, E. A., and Gooding, G. V., Jr. 1987. Use of detached leaves to evaluate tobacco haploids and doubled haploids for resistance to tobacco mosaic virus, Meloidogyne incognita, and Pseudomonas syringae pv. tabaci. Phytopathology 77:60-62. Development of disease-resistant cultivars in self-pollinated crops like virus Y. Detached leaves were maintained by immersing their petioles in tobacco (Nicotiana tabacum) can be greatly accelerated by evaluating water until symptoms appeared. Symptoms in detached leaves were similar populations of haploid plants derived from F1 hybrids resistant to various to those in intact plants, and disease reactions corresponded with wholediseases. A limitation of haploid breeding is the need to assess reactions to plant determinations. The technique can also be used with doubled haploid multiple pathogens on single plants. To avoid confounding systemic or or diploid populations segregating for disease resistance. The original lethal effects from inoculations with multiple pathogens, detached leaves intact plants with identified resistance may be evaluated for other traits, were inoculated separately with tobacco mosaic virus and Pseudomonas and susceptible genotypes may be discarded. Field evaluations for syringae pv. tabaci. Resistance to Meloidogyne incognita was identified by agronomic characteristics can then be performed on a population fixed for the associated reactions of detached leaves to the MsN R strain of potato disease resistance genes.

Incidence of potato leafroll virus (PLRV) and potato virus Y (PVY) was determined in seed potatoes (Solatium tuberosum) from Canada, Maine, Minnesota, New York, North Dakota, Nebraska, Pennsylvania, and Wisconsin used to plant the North Carolina crop in 1977, 1978 and 1979. Incidence of PLRV ranged from 0–5.2% (X = 0.57%) and for PVY from 0-5.6% (X = 0.62%) from all sources (112 seed lots). All PVY isolates (177) tested from potato caused a very mild veinbanding and mottling onNicotiana tabacum cultivars NC 95 and NC 2326. No serological difference was detected between these isolates and the common strain of PVY from tobacco in North Carolina. Essentially no spread of PVY occurred in three potato fields observed each year of the study.

Crop ScienceVolume 20, Issue 5 cropsci1980.0011183X002000050054x p. 677-677 Registration of Germplasm Registration of NC 744 Tobacco Germplasm1 (Reg. No. GP18) J. F. Chaplin, J. F. ChaplinSearch for more papers by this authorL. G. Burk, L. G. Burk Research agronomist and research geneticist, Tobacco Research Laboratory, AR-SEA-USDA, Oxford, NC 27565 and professor of crop science and genetics, North Carolina State Univ., Raleigh, NC 27560, respectively.Search for more papers by this authorG. V. Gooding, G. V. GoodingSearch for more papers by this authorN. T. Powell, N. T. Powell Professor of plant pathology, North Carolina State Univ., Raleigh, NC 27650.Search for more papers by this author J. F. Chaplin, J. F. ChaplinSearch for more papers by this authorL. G. Burk, L. G. Burk Research agronomist and research geneticist, Tobacco Research Laboratory, AR-SEA-USDA, Oxford, NC 27565 and professor of crop science and genetics, North Carolina State Univ., Raleigh, NC 27560, respectively.Search for more papers by this authorG. V. Gooding, G. V. GoodingSearch for more papers by this authorN. T. Powell, N. T. Powell Professor of plant pathology, North Carolina State Univ., Raleigh, NC 27650.Search for more papers by this author First published: 01 September 1980 https://doi.org/10.2135/cropsci1980.0011183X002000050054xCitations: 12 1 Registered by the Crop Sci. Soc. of Am. Cooperative investigations of the Oxford Tobacco Research Laboratory, AR-SEA-USDA and the Dep. of Crop Science, Genetics, and Plant Pathology, North Carolina State Univ. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume20, Issue5September–October 1980Pages 677-677 RelatedInformation