Efficient algorithms for the automatic classification of flue-cured tovacco ripeness and grading have been developed The ripeness of the tobacco was classified into 4 levels vased on the color. The lab-built simple RGB color measuring system was utilized for detecting the light reflectance of the tobacco leaves. The measured data were used far training the artificial neural network The performance of the trained network was also tested far the untrained samples. The spectrophotometer was used to detect the light reflectance and absorption of the graded tobacco leaves in the frequency ranges of the visible light The measured data and the statistical analysis was performed to investigate the light characteristics of the graded samples. The measured data were obtained from samples of 5 different grades directly without considering the leaf positions. Those data were used far training the artificial neural network The performance of the trained network was also tested far the untrained samples. The neural network based sensor information processing showed successful results for grading of tobacco leaves.

This study was made of the effects from exposure to air temperature and amount of solar radiation during the wilting period on the sunburn of burley tobacco. Tobacco stalks were cult with one hour interval from 8:00 to 16:00, and were left on the field to expose to weather, and tobacco single leaf placed under 4 temperatures regimes in indoor. Sun-burn of the leaves was occurred when the leaves were exposed to temperature higher than 33$^{\circ}C$, and to solar radiation more than 800w/$m^2$ between 11:00-15:00 in a day during the curing season. The leaf temperature was increased until 52$^{\circ}C$ under the weather condition. The tobacco leaves were also burned without solar radiation when the leaves were exposed to high temperature until 5$0^{\circ}C$ of leaf temperature. Sun-bum was increased at upper leaves and at higher moisture content of leaf.

This study was carried out to obtain the basic data which include the change of the photosynthetic rate and protein content according to growth stage in the process of senescence of tobacco plant The photosynthetic rate was the maximum with 26.31$\mu$mol.CO2/m2.sec and stomatal resistance was the minimum with 0.2552cm/sec at 15th days after leaf emergence. However, after 50 days the photosynthesis was very little occurred. During leaf developments the number of chloroplast was increased and reached at the maximum at 25th days after emergence of leaf, thereafter, it was decreased gradually. The content of protein increased continuously and showed the highest value at 15th days after leaf emergence. The degradation rate of soluble protein was more rapid than that of insoluble protein at early stage of senescence. The range of decrement in the insoluble protein was low at late stage of senescence. The content of Rubisco, the key enzyme of photoamthesis, corresponded to about 50% of soluble protein and reached to the maximum at 150 days after leaf emergence. As the senescence progressed, the content of large subunit(UV) of Rubisco showed a tendency to decrease more rapidly than that of small subunit(SSU). The total amount of amino acids was the highest at 15th days after leaf emergence.

A new flue-cured tobacco mutant line BU 8832-85 was developed at Taegu Experiment Station, Korea Ginseng and Tobacco Research Institute in 1994. KF 8832-85 was resulted from a cross of flue-cured cultivars NC 95$\times$NC 2326, and developed by a pedigree system of breeding ; initial selection was made by plant type and resistance to bacterial wilt(BW) disease(heudomonas solanaceamm) in the F2 generation under the natural field conditions infested with the pathogen. One white flowered plant was occurred by spontaneous mutation in a certain line among the F3 generatioin while the others were pink. Six plants from the seeds by selfing were selected at the field infested with the pathogen among 240 populations with white flowering in the F4, KF 8832-85 was selected based on yield and leaf quality trials among 6 lines in Fs generation. BCF 8832-85 was compared with its Parent for certain agronomic and chemical characteristics at Taegu Experiment Station in 1993 and 1994. The results showed that KF 8832-85 have white flower, the stalk height was approximately that of NC 2326 but averaged about loom taller than NC 95. It produced ground suckers as much as NC 95, and did not breakdown leaf at the same as WC 2326. KF 8832-85 have high resistance to bacterial wilt disease. Yield of KF 8832-85 was 10 and 18% higher then that of NC 2326 and WC 95, respectively. Price per Kg was equal to that of NC 2326. The contents of nicotine and reducing sugar did not differ significantly from NC 95, while total nitrogen was significantly lower than NC 95. Therefore, the new mutant line is genetically stable for agronomic and chemical characteristics and provides a source of bacterial wilt disease resistance for use in breeding resistant flue-cured cultivars. Key words : Mutant line, White flower, Spontaneous mutation.

Structures of the adventitious root meristem induced from callus culture of tobaco (Nicotiana tabacum cv. NC 82) leaves were investigated by light and transmission electron microscopy. Structural differences between in vitro root and callus cells were also examined by the microscopy. The submicroscopic features of the in vitro root cells were as follows. Intercellular spaces were not developed and nuclei with two nucleoli were observed occasionally. Plasmodesmate were found in groups or sing1y on transverse and longitudinal walls. Amyloplast solely filled with starch grains, with one to five electron - dense bands, was surrounded by single membrane. in the callus cells, vacuolization of central part in the cytoplasm having mitochondria with swollen cristae and starch grains like those of in vitro root cells was a distinct feature. Vesicles which were found between cell wall and plasma membrane may be arisen by a process of protoplasmic invagination. By comparing of ultrastructures between the cells of callus and in vitro roots we found that the distinct differences lied on thickened cell walls and hypertrophed vacuoles in the former, and less thickened cell walls and several small vacuoles in the later.

Tobacco mosaic virus (TMV), TMV-common strain, causes severe damage on flue-cured tobacco in Korea. As the results, breeding programs were conducted to transfer the TMV resistance from NC567 to other cultivars. Advantage of F1, hybrid may not lie only in their heterotic value but also in directly combining of valuable dominant traits, e.g. for disease resistance, either in pairs or as groups already assembled in the two parents. A new TMV resistant flue-cured tobacco variety KF114 was developed from a cross as maternal parent MSNC567 and NC82 at the Suwon Experiment Station. KF114 was more vigorous growth characteristics in early stage than that of NC82, standard variety in Korea, and other characters were similar to those of NC82. It os high resistance to TMV, but bacterial wilt(Pseudomonas solanacerum) and black shank (Phytophthora parasitica var. nicotianae) is comparable to NC82. It should adapt well to the flue-cured production area and can reduce premature flowering under unfavorable weather conditions. Yield of KF114 is 1% to 5% higher, and nearly equal in value per KG compared with NC82. This variety, F1 hybrid, met acceptable standards for chemical and physical characteristics of cured leaf and high ranked good smoking taste by panel members in Korea Ginseng and Tobacco Research Institute.

Morphology, chromosome and transmission of potato virus Y(PVY) of the green peach aphid populations collected from tobacco fields were examined. Based on the morphological characteristics, especially values of linear discriminant functions and length of ultimate rostral segment, 8 green peach aphid clones with different color morphs could be divided into two groups, namely Myzus persicae and M. nicotianae, according to the proposal by Blackman in 1987. The red (RED)-, Brown (BRN)- and green-colored (GR1, GR2) aphid clones belonged to the M. nicotianae type, while the pale green (PG1, PG2, PG3) and dark brown (DBR) clones to the M. persicae type. The karyotype of the pale green-colored clone (PG1, M. persicae type) appeared normal and was 2n=12 with no indication of chromosomal translocation. On the contrary, in the green-colored aphid clone (GR1, M. nicotianae type), translocation and dissociation of autosome 3 were often found, having karyotype of 2n=13. Both of the above aphid clones transmitted PVY-VN to tabacco plants (cv. Burley 21), but the GR1 clone had higher transmissibility than the PG1 clone.

Black shank(Phytophthora parasitira roar. nicotianae) resistant burley tobacco (Nicotiana tabacum L.) germplasms, KB 104 and KB 106, were developed by Korea Ginseng & Tobacco Research Institute. KB 104 was developed from the single cross of Burley 21$\times$Newton 77, using a modified pedigree method. KB 104 was highly resistant to black shank, and its agronomic characteristics and chemical contents were comparable to those of Burley 21, and value per 10a was slightly higher than Burley 21, KB 106 is a maternally derived doubled haploid made by N. africana method from the single cross of Burley 21$\times$ Va 509. KB 106 was also highly resistant to black shank, had two more harvestable leaves per plant and flowered three days later than Burley 21 did. Total alkaloid and nicotine contents of KB 106 were significantly lower than those of Burley 21. But its nornicotine content was higher than Burley 21 5. Key wads : Burley tobacco germplasm, Black shank resistance.

Deliveries of tar, nicotine and carbon monoxide in mainstream smoke decreased with increment of exogenous potassium content of tobacco. Potassium malate was more effective than potassium nitrate, potassium carbonate, potassium citrate and potassium oxalate for the reduction of carbon monoxide, but potassium nitrate was more effective than potassium palate, potassium carbonat, potassium citrate and potassium oxalate for the reduction of carbon in the case of nicotine. Puff count and burning rate were slightly changed with added potassium salts.

A study of expanding tobacco includes the steps of adjusting the moisture content of cut tobacco, without the use of exogenous impregnants by contacting the filler with a high velocity gaseous medium at elevated temperature such that heat is rapidly and substantially uniformly transferred from the medium to the filler for a total contact time sufficient to expand the tobacco leaves. Study is disclosed for drying and expanding cut tobacco by introducing the tobacco into an elongated tubular shaped conduit through which steam high temperature 150-35$0^{\circ}C$ and high velocity above the 18m1sec, super steam is recycled. moisture content of shreded tobacco leaves, immediately before treatment within the range of from 10% to 24% and, most preferably, within the range of from 18% to 21%. Expanding rate showed 70% in NC -82(B.3) and 42% in Burley -21(B.1) which is produced in 1993 under this condition. When expanding tobacco expanded tobacco did not change significally, but they were decreased at 27$0^{\circ}C$ very largely. The curtailment of cost price and physical and chemical properties of various items were improved in cigarettes. Key words : Expanding tobacco, Super steam tobacco expansion, Fast drying tobacco, High temperature treat tobacco, Puffing tobacco.

On the basis of the literature, which is at present still scientific information improvable, the results of research done so far into the occurrence and analytical methodology of major markers of environmental tobacco smoke(ETS) have been summarized. Key areas addressed are: differences in physicochemical composition between mainstream smoke, sidestream smoke and ETS: techniques for field measurement of ETS: relationship between indoor air quality with ETS and its distribution view of US EPA and its problems: biological effects and concerning estimation of ETS exposure.