• Korean Journal Plant Pathology
• /
• v.1 no.1
• /
• pp.17-21
• /
• 1985

Microbial antagonism between virulent and avirulent isolates of Pseudomonas solanacearum was studied in relation to the control of bacterial wilt of tobacco. In nutrient broth media or in soil, the avirulent isolate of P. solanacearum grew faster than did the virulent one. Inhibitory effect of avirulent isolate against growth of virulent one was negligible in mixed culture of the two isolates. The disease severity of bacterial wilt was significantly reduced when the roots of cultivar BY 4 susceptible to bacterial wilt was dipped in suspension of an avirulent isolate for 6 hours prior to transplanting to the soil infested with virulent bacteria. When the seedlings of tobacco were poured with the suspension of an avirulent isolate onto the soil in pre-planting pots 24 hours before ransplanting, there was a significant reduction in disease severity in the field. However, the reduction was noticed until early July, but after middle of July, no difference between the avirulent isolate-treated and non-treated plants was found in severity of the bacterial wilt.

• Korean journal of applied entomology
• /
• v.23 no.2 s.59
• /
• pp.96-101
• /
• 1984

This experiment was carried out to investigate control efficacy by cultural practice and fumigation of tacterial wilt caused by Pseudomonas solancearum in resistant tobacco line NC82 at the Korea Ginseng and Tobacco Research Institute, Eumseong Experiment Station in 1982 and 1983. The bacterial wilt of tobacco occurred severely from mid-July to last August in applicable temperature and soil humidity for increasing bacteria. Disease severity appeared low and slowly at fumigation and resistant variety treatment. Incidence of bacterial wilt in tobacco line NC82 was $44.7\~55.8\%$ being compared with susceptible variety, NC2326 and $95\~99\%$ when resistant variety, NC32 was cultivated with soil fumigation treatment. Control efficacy of cultural practices appeared low with $0.8\~20\%$ and was not different from resistant variety and fumigation treatment. Control system against bacterial wilt in flue-cured tobacco was accomplished by control efficacy over $95\%$ when resistant variety(NC82) was cultured after treatment of cultural practices (Tillering after harvest and before transplanting, stalk and root destruction, early transplanting early removal of the mulching film) and soil fumigation(Cylon).

• Journal of the Korean Society of Tobacco Science
• /
• v.14 no.2
• /
• pp.97-103
• /
• 1992

KB 101 is a bacterial wilt(Pseudomonas solanaceamm E.F. Smith) and black shank (Phytophthora nicotianae Breda de Haan Var. nicotianae Waterhouse) resistant cultivar of burley tobacco (Nicotiana tabacum L.) KB 101 was developed by the Korea Ginseng&Tobacco Research Institute, and released in 1987. KB 101 was developed from a single plant selection in the F2 generation derived from the double cross, [(Burley 21X Burley 37) X (Burley 64X Ky 16)]. Burley 37 and Burley 64 were the source of resistance to bacterial wilt and black shank. Yield trials were conducted in the Fs through F6 generations at the four Exp. Stn. of Korea Ginseng &Tobacco Research Institute as JB 7705-1. On-farm yield trials were conducted in the F7 through F9 generations at the 45 locations of burley tobacco growing area from 1984 to 1986 as KB 101. KB 101 has an erect growth habit similar to that of Burley 21: plant size is larger and has more leaves than those of Burley 21. It is late maturing cultivar that flowers approximately 3 days later than Burley 21. The physical characteristics and chemical composition of KB 101 were similar to those of Burley 21.

• Journal of the Korean Society of Tobacco Science
• /
• v.11 no.2
• /
• pp.149-155
• /
• 1989

This study was conducted to obtain the breeding information for the leaf breakdown, and correlation coefficients between leaf breakdown and some agronomic characters in flue-cured tobacco at Taegu Experiment Station, Korea Ginseng & Tobacco Research Institute. NC 95 and NC 2326 were used as parents. The bulk method procedure was used from the F2 to the F4 generations, 54 plants were selected among F4, and 11 lines were selected among 54 F5 which based on high resistance to bacterial wilt compared with NC2326. The entries were composed of parents and 11 F6 advanced lines, and designed in randomized block with 3 replications. Plant seedlings were transplanted in 16 April. The number of breakdown leaf were investigated at flowering stage, 18 June. There were significant difference between NC 95 and NC 2326 for the number of breakdown leaf, number and weight of ground suckers, days to flower, yield and resistance to bacterial wilt, and similar results were appeared among lines. Estimated heritability in the broad-sense ranged from 59.3% to 87.4% for all characters. Most of genetic correlations were higher than phenotypic coefficients between characters. Number of breakdown leaf was positively correlated with days to flower, the number and weight of ground suckers, while it was negative to yield. One line among 11 had few breakdown leaf, low producted ground suckers and high resistance to bacterial wilt. Above results suggest that the number and weight of ground suckers can be use as a selection criterion for leaf breakdown even under the condition without leaf breakdown.

• Research in Plant Disease
• /
• v.13 no.1
• /
• pp.1-5
• /
• 2007

Major diseases of tobacco and farmer's control practices were surveyed in the Kyeongbuk province area from 2005 to 2006. Mosaic caused by potato virus Y and bacterial wilt caused by Ralstonia solanacearum were most severe during the harvest season. Compared with the disease occurrence of ten years ago, the damage by tobacco mosaic virus reduced but bacterial wilt increased. These changes in the disease occurrences may probably be due to releasing the resistant tobacco cultivar to the mosaic virus but susceptible to the bacterial wilt pathogen. More than thirty percentage of the farmers have misused fungicides and also have applied the continuous mono-cropping system for more than ten years, and have chosen the incorrect crops for the rotation.

• Journal of the Korean Society of Tobacco Science
• /
• v.14 no.2
• /
• pp.116-125
• /
• 1992

This experiment was conducted to examine characteristics of agronomic characters and estimate of gene effect for several mutant characters. The genetic populations were derived from cross between 83H-5 and Hicks. There were significant difference for plant height, stlk height, leaf shape and bacterial wilt disease index except leaf number, leaf length, and what is more, F3 variance is more than Bl and B2 generation from cross 83H-5 X Hicks. Gene actions for stalk height and bacterial wilt disease were estimated by 3-parameter, and by 6- parameter model for all characters except above two characters but stalk height and bacterial wilt disease index are not significant in the additive and dominance effects. Dominant$\times$dominant epitasis for plant height, dominant and dominant$\times$dominant epistasis for leaf length, additive and additive$\times$additive and dominant$\times$dominant epistasis for leaf width, and additive and additive$\times$dominant epistasis for days to flower were appeared significant in gene action.

• Research in Plant Disease
• /
• v.8 no.2
• /
• pp.78-83
• /
• 2002

Tobacco diseases have not been recorded until 1900s in Korea, where tobacco plants were introduced at early 1700s. Practical researches on the disease have been conducted since mid 1960s. Major ten tobacco diseases were mosaic caused by tobacco mosaic virus·potato virus Y·cucumber mosaic virus, bacterial wilt, hollow stalk, wild fire caused by angular leaf spot strain, black shank, brown spot, powdery mildew and fusarium wilt. But their annual occurrences were varied according to changes of tobacco varieties and their cultivating practices. As no useful chemicals, several biological tactics have been developed to control the viral or bacterial diseases that give significant economic damages on sustainable crop yield, but not practicable to field farming condition yet. Transgenic tobacco plants containing foreign disease resistant genes have been developed by current bio-technology, but not released to farmers yet. Though some disease-resistant tobacco varieties have been developed by the conventional breeding technology and currently used by farmers, their disease controlling efficacy have been diminished by occurrence of the new strain or race. Future research on tobacco diseases has been focused on technical development to produce high quality tobacco with less production cost, which leads Korean tobacco industry to keep its competence against foreign industry and decreasing overall market.

• Proceedings of the Korean Society of Tobacco Science Conference
• /
• 2004.05a
• /
• pp.25-25
• /
• 2004

• Journal of the Korean Society of Tobacco Science
• /
• v.15 no.1
• /
• pp.34-48
• /
• 1993

This experiment were conducted to investigate heterosis and combining ability for several mutant characters by analyzing dialled crosses of flue-cured tobacco. In a dialled cross of 3 flue-cured varieties and the mutant line 83H -5, the heterosis was somewhat higher in Fl than in F2. For growth character, the heterosis was 0.28-6.03% in plant height, leaf number, leaf shape index and yield, and was 43.2% for bacterial wilt disease index. The mutant line 83H-5 showed significantly negative GCA effect for plant height, leaf width and bacterial wilt disease index in Fl and F2, leaf length in F2, and positive GCA effect for total alkaloids, total nitrogen in Fl and days to flower in F2, respectively. Specific combining ability(SCA) in 83H-5 x Hicks was significant in negative effect for leaf length(F2), number of leaves(F2), leaf shape(F1, F2), bacterial wilt(F2) and alkaloids(F1), and in 83H-5 x NC 2326 in positive effect for leaf length(F1, F2) and leaf width(F2), and for 83H-5 x NC 82 in positive effect for plant height(F1, F2) and leaf width(F2), and for 83H-5 x NC 82 in Positive effect for Plant height(F1, F2), leaf length(F2) and yield(F1, F2).

• Journal of the Korean Society of Tobacco Science
• /
• v.14 no.2
• /
• pp.126-132
• /
• 1992

This experiment was conducted to examine estimates of heterosis, degree of dominance, heritability and phenotypic and genotypic correlation for several mutant characters in flue-cured tobacco variety. Significant heterosis was noted, recording 2.73 and 6.16% for leaf width, -6.86 and -4.72 for leaf shape index, 19.8 and 23.4% for bacterial wilt disease index in Fl an4 F2 generation, respectively, and -1.44 for days to flower in F2 generation. And also leaf width was appeared partial dominance in Fl, and leaf shape index in Fl and F2, Leaf width in F2 was appeared overdominance. Estimated heritabilities in the broad sense ranged from 0.77 to 0.87 for plant and stalk height and days to flower, while those of leaf number, leaf length and width, leaf shape index and bacterial wilt disease index ranged from 0.50 to 0.65. And the heritabilities in the narrow sense were appeared 0.64 and 0.72 for stalk and plant height, respectively, and the others were ranged from 0.32 to 0.47 Positive genotpic correlations appeared among plant height, stalk height, leaf length and leaf width, and between leaf shape index ands day to flower. And negative genotypic correlations appeared between leaf shape index and plant height and stalk height and leaf width, and between bacterial wilt disease index and leaf length.