Nicotiana tabacum L., cultivated tobacco, is one of 65 species in the genusNicotiana. Over the past 30 years, varying numbers of the species have been included in tests of resistance to tobacco diseases by research workers in tobacco-producing areas throughout the world. This report summarizes these investigations in tabular form and discusses methods whereby interspecific transfer of disease resistance may be accomplished.

Crop ScienceVolume 24, Issue 6 cropsci1984.0011183X002400060067x p. 1220-1220 Registration of Germplasms Registration of LMAFC 34 Tobacco Germplasm James F. Chaplin, James F. ChaplinSearch for more papers by this authorL. G. Burk, L. G. BurkSearch for more papers by this author James F. Chaplin, James F. ChaplinSearch for more papers by this authorL. G. Burk, L. G. BurkSearch for more papers by this author First published: 01 November 1984 https://doi.org/10.2135/cropsci1984.0011183X002400060067xCitations: 11AboutPDF 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 Volume24, Issue6November–December 1984Pages 1220-1220 RelatedInformation

Total alkaloids (predominately nicotine) are important constitutents in flue-cured tobacco ( Nicotiana tabacum L .). Due to varying nicotine levels in cigarettes, it is of interest to see what effect varying alkaloid levels in tobacco have on certain agronomic and chemical characteristics of the cured leaf. Experiments were conducted at two locations to develop lines of flue-cured tobacco with different levels of total alkaloids and to evaluate these lines for agronomic, chemical, and smoke characteristics. Three flue-cured cultivars with different total alkaloid levels were chosen as recurrent parents. The parents and alkaloid levels were: 'Coker 139' (1.88%), 'NC 95' (3.28%), and 'SC 58' (4.51%). Each cultivar was crossed with a low alkaloid line (0.20%). After the initial cross, backcrosses were made in each F 2 population between a low alkaloid plant and its respective recurrent parent. BC 5 F 7 generation plants with different levels of total alkaloids were selected and advanced to the BC 5 F 7 to obtain stable lines. Also dihaploids were developed from BC 5 F 7 plants and lines with different levels of total alkaloids were selected. Both the BC 5 F 7 and dihaploid populations were evaluated. Based on these tests the line with the highest yield and grade index at each alkaloid level was further evaluated for total alkaloids, reducing sugars, yield, grade index, days to flower, plant height, and number of leaves per plant. Lines with the following levels of total alkaloids were evaluated: NC 95 family - 0.34, 1.08, 2.05, 3.11, and 3.55%; SC 58 family - 0.38, 1.59, 1.90, 2.82, 4.18, and 4.82%; and the Coker 139 family - 0.20, 0.93,1.66,1.84, and 2.17%. The 1.08% line in the NC 95 and 1.59% line in the SC 58 families were dihaploids. None of the lines converted appreciable amounts of nicotine to nornicotine. Therefore, the total alkaloid levels reflected predominantly nicotine. In most families the high alkaloid lines gave the highest grade index. Days to flower, plant height, and number of leaves per plant were not associated with total alkaloid levels in cured leaf. Cigarette smoke from the different tobacco lines was evaluated by two smoke panels. The results from Panel A indicated that it was difficult to associate any of the taste parameters with levels of total alkaloids in the leaf. The results from Panel B indicated that an increase in total alkaloids in the leaf was accompanied by an increase in flavor of the smoke.

Crop ScienceVolume 21, Issue 5 cropsci1981.0011183X002100050054x p. 802-802 Registration of Germplasm Registration of I-35 Tobacco Germplasm1 (Reg. No. GP19) J. D. Miles, J. D. Miles Research agronomist (retired). AR-SEA-USDA. Tifton, GA 31791.Search for more papers by this authorJ. F. Chaplin, J. F. ChaplinSearch for more papers by this authorL. G. Burk, L. G. BurkSearch for more papers by this authorA. H. Baumhover, A. H. Baumhover Research agronomist, research geneticist (retired) and research entomologist respectively, Tobacco Research Laboratory, AR-SEA-USDA, Oxford, NC 27565.Search for more papers by this author J. D. Miles, J. D. Miles Research agronomist (retired). AR-SEA-USDA. Tifton, GA 31791.Search for more papers by this authorJ. F. Chaplin, J. F. ChaplinSearch for more papers by this authorL. G. Burk, L. G. BurkSearch for more papers by this authorA. H. Baumhover, A. H. Baumhover Research agronomist, research geneticist (retired) and research entomologist respectively, Tobacco Research Laboratory, AR-SEA-USDA, Oxford, NC 27565.Search for more papers by this author First published: 01 September 1981 https://doi.org/10.2135/cropsci1981.0011183X002100050054xCitations: 5 1 Registered by the Crop Sci. Soc. of Am. Cooperative investigations of the Oxford Tobacco Research Laboratory, AR-SEA-USDA, Georgia Coastal Plains Exp. Sin. and the Dep. of Crop Science, Genetics and Entomology, North Carolina State University, Raleigh, NC 27650. 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 No abstract is available for this article.Citing Literature Volume21, Issue5September–October 1981Pages 802-802 RelatedInformation

Journal Article Significance of multiple shoots on haploid plantlets of tobacco Get access L. G. Burk L. G. Burk Research geneticist Tobacco Research Laboratory, AR, Science and Education Administration, U. S. Department of AgricultureOxford, NC 27565, and professor. Department of Genetics, North Carolina State UniversityRaleigh, NC 27650 Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Heredity, Volume 72, Issue 1, January 1981, Pages 67–68, https://doi.org/10.1093/oxfordjournals.jhered.a109434 Published: 01 January 1981

Numerous chromosome‐doubled haploids (dihaploids) were obtained from cultured anthers of a tobacco (Nicotiana tabacum L.) hybrid with multiple disease resistance. Field plot tests of dihaploid progenies were made in 1977 (in the absence of diseases), and some of the highyielding entries observed in 1977 were included in a 1978 planting. The selections grown in 1977 consisted of four groups based on their resistance or susceptibility to Tobacco Mosaic Virus (TMV) and Potato Virus Y (PVY).Unlike dihaploids from inbreds, some of the dihaploids from the hybrid yielded significantly more than the midparent (MP). Four yielded more than the MP 1977, and six yielded more in 1978. Most of the entries that produced high yields in 1977 were also high‐yielding in 1978. Alkaloid values were extremely variable among dihaploid lines and highly uniform within them. Values for agronomic traits, averaged among entries in the group that was susceptible to TMV but resistant to PVY, indicated that the gene for PVY resistance was associated with increased yields and high grade indexes (values). Resistance to TMV or root knot (RK), caused by Meloidogyne incognita (Kofoid and White) Chitwood, was not particularly beneficial to the groups of entries that possessed those genes. However, individual entries with the same combinations of genes for resistance/susceptibility were found to be high‐yielding; some, contrary to expectation, also had high grade indexes. This finding suggests that large numbers of dihaploid lines should be evaluated to assure identification and selection of exceptional individuals for use as breeding stocks or as varietal candidates. The occurrence of exceptional in. dividuals from a hybrid anther source, coupled with the fact that a dihaploid is a true‐breeding, homozygous diploid, obtained in a single generation, offers encouragement for progress in breeding high‐yielding, disease: resistant tobacco.

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

The productivity and leaf chemical composition of random dihaploid (DH) and single‐seed‐descent (SSD) lines of Nicotiana tabacum L. from the same F1 hybrid plant, were compared. ‘Hicks Broadleaf’ was crossed with ‘Coker 139,’ anthers from a single F1 plant were cultured, and 50 DH lines were produced for testing. The same F1 was selfed, and 50 random F8 lines were developed by the SSD procedure. Experimental lines and check cultivars were compared in three environments.The DH population yielded 10.6% less cured leaf, possessed inferior leaf quality, was later flowering, produced reduced leaf numbers, and its cured leaf was lower in total alkaloids than the SSD population. The antherculture procedure produced a DH population with greater genetic variability for leaf yields than the conventionally‐inbred population, but the suppressed DH mean overwhelmed the benefit of increased variation. Results indicate that selection in SSD populations would be preferable to selection in DH population for the identification of superior genotypes.

Abundant seeds of high germinability are obtained when Nicotiana tabacum is pollinated by Nicotiana africana . Most of the seedlings die at the cotyledonary stage. The remaining seedlings are viable F 1 hybrids or maternal haploids that can be easily distinguished. This simple method of producing Nicotiana tabacum haploids offers an alternative to anther culture.

Journal Article Interspecific hybridizations with an African tobacco, Nicotiana africana Merxm Get access D. U. GERSTEL, D. U. GERSTEL Dr. Gerstel and Ms. Bums are affiliated with the Crop Sci ence Department, North Carolina State UniversityRaleigh, NC 27650 Search for other works by this author on: Oxford Academic PubMed Google Scholar J. A. BURNS, J. A. BURNS Dr. Gerstel and Ms. Bums are affiliated with the Crop Sci ence Department, North Carolina State UniversityRaleigh, NC 27650 Search for other works by this author on: Oxford Academic PubMed Google Scholar L. G. BURK L. G. BURK Mr. Burk is a member of the Department of Genetics at the same institution and is research geneticist, USDA-SEA-AR, Oxford Tobacco Research LaboratoryOxford, NC 27565 Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Heredity, Volume 70, Issue 5, September 1979, Pages 342–344, https://doi.org/10.1093/oxfordjournals.jhered.a109270 Published: 01 September 1979

Methods are described for producing large numbers of haploid plantlets from anthers of a flue-cured tobacco hybrid with monogenic resistance to tobacco mosaic virus, (TMV), potato virus Y (PVY) and root knot (RK), respectively. Additional details are given on colchicine treatment for converting haploids to doubled haploids (DH's) and on the frequency of spontaneous DH's among untreated plantlets. Disparate genetic ratios of TMV-resistant to TMV-susceptible plants were obtained among colchicine-treated haploid plantlets, induced DH's and untreated haploids when compared with F2 and BC1 progenies. Haploids (gametes) with the gene for TMV resistance occurred more frequently than expected and plantlets with the gene for RK resistance occurred less frequenctly than expected. Transmission of the gene for PVY resistance differed only slightly from Mendelian expectations. These unexpected ratios, in addition to the frequent occurrence of plastid chimeras among anther-derived plantlets, strengthened our conviction that haploidy is somehow associated with mutation.

Previously, it was shown that a fragment chromosome, apparently derived from the Nicotiana repanda chromosomal complement, restores to normal the morphology and fertility of the abortive and feminized anthers produced by plants that possess the N. tabacum genome in cytoplasm from N. repanda. Furthermore, that restorer chromosome organizes the nucleolus and inhibits the nucleolus-forming activity of the nucleolar organizers of N. tabacum chromosomes present in the same cells, particularly in pollen mother cells. To determine whether these relations are basic or only coincidental, restorer chromosomes for other cytoplasms are now being investigated. The present paper describes a study of a chromosome, presumably derived from N. debneyi, with partial restoring power. Acting in the cytoplasm of N. debneyi, it directs formation of morphologically normal anthers, without, however, restoring pollen fertility. We find that this chromosome also has a functioning nucleolar organizer, but only slightly inhibits the nucleolus-forming capacity of N. tabacum chromosomes. The suggestion of a relationship between the nucleolar apparatus and restoration of normal anthers is thus strengthened by the observation that restorers are found on nucleolus-forming chromosomes from two very distinct Nicotiana species, as well as in several comparable cases cited from the Triticinae. The manner in which the nucleolus, or its organizer, may direct defeminization and restoration of anther morphology is not known; suggestions were offered in the preceding paper in this series (Gerstel, Burns and Burk 1978).

Dihaploid lines of tobacco (Nicotiana tabacum L.) were developed from anther cultures of two long‐term, conventionally inbred cultivars. Ten dihaploids from ‘Coker 139’ and 10 dihaploids from ‘NC 95’ were selfed and randomly crossed to produce 10 dihaploid F1's. Each F1 was selfed to produce a dihaploid F2. The conventional cultivars were crossed to produce a conventional F1, which was selfed to produce an F2. All genetic materials were evaluated for agronomic performance and chemical composition.Dihaploid lines grew more slowly, yielded approximately 15% less, and were agronomically inferior to their conventional pure‐line parents. Dihaploid F1's and F2's yielded less than the conventional F1 and F2. Enforced complete homozygosity in tobacco may not be entirely responsible for the reduction in yield of dihaploid lines developed by anther culture methods. The dihaploid technique as presently employed may be mutagenic.Reduced yields of dihaploid lines produced by the anther culture technique and the inferiority of crosses of dihaploid lines compared to conventional entries, suggest that this technique may not be suitable for a tobacco breeding program, where increased yield is of primary interest.

The cytoplasm of Nicotiana species has been shown to be the site of a sensitive or insensitive response to tentoxin, a cyclic tetrapeptide. This cytoplasmic trait can be used to identify the maternal parent in an interspecific hybrid wherever the parents have different reactions to tentoxin. Under certain circumstances it can also monitor the presence of cytoplasm of a nonrecurrent parent in successive generations of a backcross-derived line that is being substituted with the genome of another species. The tentoxin response can also be used to support hypotheses or to reexamine speculations, based on cytotaxonomic and biochemical evidence, about relation ships among extant Nicotiana species.