• Korean journal of applied entomology
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• v.39 no.3
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• pp.157-163
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• 2000

In a previous report, 50 potato cultivars were screened for infestation levels by the coppery click beetle (Selatosomus puncticollis Motschulsky) in the field. Subsequently, we selected 10 potato cultivars (Anco, Atlantic, Bintje, Dejima, Denali, Jopung, Irish Cobbler, Namsuh, Shepody, and Superior) to evaluate feeding preferences by wireworms, and to analyze some factors associated with resistance. The injury rates and number of holes in potato tubers damaged by larvae of S. puncticollis were checked in the field and laboratory. Additionally, some of their chemical characters (contents of glycoalkaloids, total-nitrogen, Ca, K, Mg, sugars, and starch) were quantified. And finally correlation analysis was conducted to see whether there is a possible relationship between these characteristics and the damage level. The tuber injury rates by S. puncticollis larvae were generally high showing 19% to 73% of damage level. The highest number of tuber hole damaged by S. puncticollis larvae was found on cv. Namsuh, but generally fewer on cvs. Anco, Atlantic, Bintje, Denali and Superior. No activities for $\alpha$-chaconine, $\alpha$-solanine and $\alpha$-tomatine at a concentration of 2,500 ppm were found to S. puncticollis larvae. The contents of glycoalkaloids in tuber were different depending on cultivars. In tubers, cv. Superior contained the highest level of 18.8 mg%, but cv. Irish Cobbler had the lowest level of 6.39 mg%. Concentrations of reducing sugars and total free sugars in tubers of cv. Namsuh were 0.71 % and 2.95%, but 0.26% and 1.77% in those of cv. Dejima, respectively. For the content of potato starch, cvs. Bintje, Dejima and Irish Cobbler showed higher level, but cvs. Jopung and Shepody lower. The highest contents of total nitrogen, Ca, K and Mg in tuber were found on cvs. Anco, Atlantic, Anco and Jopung, respectively. From correlation analyses, injury rate by S. puncticollis larvae was correlated with total nitrogen content (r = -0.71435*) and total sugar content in tuber (r = 0.78018*). Such information will become essential in developing integrated pest management programs and also in breeding new potato cultivars resistant to the wireworms.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.3
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• pp.250-254
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• 2011

The study was carried out to evaluate the affect of proton beam radiation on production of bulbil and tuber including change of endogenous gibberellins, of Dioscorea opposita Thunb. The yield of bulbils and tubers from non- and irradiated D. opposita Thunb at doses of 5, 10, 15 and 20 Gy were determined. Endogenous gibberellins were also quantified by GC/MS analysis. D. opposita tubers irradiated at 15 Gy produced higher bulbil production than non-irradiated plants. Enlarged bulbil (above size diameter 4 mm) was significantly increased at 15 Gy. Bioactive endogenous $GA_4$ was dominant in bulbils and tubers irradiated with proton beam rather than $GA_1$. Major gibberellins biosynthetic pathways in bulbils and tubers of D. opposita plants were non C-13 hydroxylation route. From the results of this study, 15 Gy proton beam radiation was suggested as an optimal dose that can produce high amounts of bulbil for mass production of D. opposita plant.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.8 no.1
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• pp.83-89
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• 1970

Investigation was made to know the effects of the time of transplanting and harvesting, fertilizer, soil texture and period of storage on tuber yield and starch content of sweet potato. Variety used was Shin-mi, one or the leading varieties in Korea. Late transplanting, early harvesting, and balanced application of nitrogen, phosphorous and potassium, and loam and coarse sandy loam were more effective in increasing starch content than early planting, late harvesting, and more application of potassium and none application of phosphorous, and light clay respectively. Long storage period resulted in reducing starch content.

• Research in Plant Disease
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• v.11 no.2
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• pp.122-127
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• 2005

Late blight of potato caused by Phtophthora infestans is one of the most destructive disease in organic farming as well as in the conventional cultivation in Korea. Incidence and progress of the disease largely depend on climatic conditions around the fields. However, the disease completely destroys whole leaves of the plant within two weeks in organic farming fields. While, potato leaves in conventional farming fields remain healthy for 5 weeks after the first symptom appearance, because fungicides were applied four times in average to control the disease. Area under disease progress curve (AUDPC) of organic farming fields ranged from 2314 to 2421 and quickly expanded compare to that of conventional farming fields. The tuber yield in the organic farming fields ranged from 0.96 ton per 10a to 1.5 ton per 10a, while it was 2.7 ton per 10a in conventional farming fields. Tuber yields were reduced to $42\~63\%$ by the infection of late blight and the reduction rate was closely related with the time of first occurrence of the disease in organic farming fields. Physiological races of the pathogen were diversified with R0,1,3,4,5,7,10,11 in organic farming fields at Hongchun area. Pathogen races were distributed with similar pattern at different areas of organic farming fields.

• Korean Journal of Medicinal Crop Science
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• v.4 no.4
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• pp.340-344
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• 1996

This experiment was conducted for the production of alismatis rhizoma (Alisma plan­tago-aquatica var. orientale Samuelsson) with high root tuber yield and alisol-B monoacetate content by treatment of different fertilizers levels. The results obtained were as follows: Shoot growth tended to in­crease as the fertilizers levels increased. Root tuber yield increased by 25% and 20% with 20-10-20 and 30-15-30 treatment, respectively. Alisol-B monoacetate contents increased as fertilizers levels increased, being the highest in 30-15-30 treatment.

• Korean Journal of Medicinal Crop Science
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• v.26 no.4
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• pp.296-301
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• 2018

Background: The objective of this study was to investigate the effect of packaging material on the growth of rootstock of Liriope platyphylla. Methods and Results: This study examined the effects of two types of packaging material, LDPE (low density polyethylene) and functional film on the growth of the tubers of L. platyphylla, at $5^{\circ}C$. During the 16-weeks of storage period, the ratio of loss and decay of the tubers was examined at intervals of 4, 8, and 16 weeks to detect the quality of the plant. After 16 weeks of storage, the treated tubers were own. Subsequently, plant height and the number of leaves were recorded. The results revealed that functional film at $5^{\circ}C$ was the ideal material for the storage of L. platyphylla tubers. The rate of loss was the highest (57.42%) with a onion net and the lowest (22.12%) with a functional film. Similarly, the rate of tuber decay was highest (8.20%) using onion net and the least (4.60%) when the functional film was used. Conclusions: Thus, the use of the functional film proved to be the most effective in the storage of L. platyphylla tubers when compared with the LDPE.

• Korean Journal of Medicinal Crop Science
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• v.26 no.5
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• pp.445-445
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• 2018

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.1
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• pp.54-62
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• 2015

To analysis of virus free sweetpotato effect, 5 virus free sweetpotato and virus normal sweetpotato varieties were planted in 5 different regions at 2010 year. The average yields of virus free sweetpotato are showed different results according to regions. Sinjami which cultivated at Iksan were increased maximum 68% compare to normal. However, Sinjami which cultivated in Hamyang were decreased yield 11% compare to normal. Analysis of tuber formation ratio of Sinjami, Yenhwangmi, Singeonmi which cultivated in Nonsan were decreased tuber number compare to normal. However, 3 varieties were all increased on Average storage root weight and yield of marketable storage root. In the results of analysis of marketable storage root according to cultivated regions and varieties, all varieties except Sinjami which cultivated in Hamyang were increased yield. Also, quality of virus free sweetpotato were enhanced 7 to 9 compare to virus infected sweet potato which showing average 3. Contents of starch between virus free and virus infected sweetpotato were not affected by virus. Virus free sweetpotato were more increased starch products according to increased total production yield. Also, $Brix^{\circ}$(%) was not showing difference between virus free and virus infected sweetpotatoes. In this experiment, Virus free sweetpotato are enhanced production yields and quality. Therefore, we suggested that virus free sweetpotato is one of the methods to reduce damage by sweetpotato virus.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.2
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• pp.146-154
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• 2021

This study was conducted to determine the degree of reduction in the yield of sweetpotato subjected to different shading treatments according to the growing season of the typical viscous sweetpotato 'Hogammi' and the powdery sweetpotato 'Jinyulmi'. Shading was provided using commercially available shading nets (55% and 75% shading level), and the treatments were applied at the following stages of storage root growth: SFS: the storage root formation stage (planting-50^th day), SSS: the storage root swelling stage (50-90^th day), and SAS: the storage root actively swelling Stage (90-120^th day). The growth characteristics according to shading treatments during each growth period, the number of tubers obtained at harvest, and sugar contents were investigated. For both assessed cultivars, there was no significant difference between the control group and the 55% shading treated group with respect to the maximum quantum yield (Fv/Fm) of photosystem II under different shading treatments, whereas the 75% shading group showed slightly higher values than the control group. In both cultivars, the contents of chlorophyll a and b tended to increase in plants subjected to shading treatments compared with the control plants, particularly that of chlorophyll b. Compared with the control group, the chlorophyll b content of 'Hogammi' subjected to 55% and 75% shading increased by 47% and 41%, respectively, whereas that of 'Jinyulmi' increased by 39% and 34%, respectively. We also detected reductions in the dry weights of the above- and belowground parts of the two varieties in response to shading compared with the control, with the reduction in the dry weight of belowground parts being significant. Furthermore, in both varieties, the T/R rate tended to increase in response to shading treatment. Owing to the lack of sunlight, both cultivars tended to suppress the formation and enlargement of tuber roots. Consequently, post-harvest yield analysis revealed that under shading treatments, both cultivars were characterized by poor tuber root growth according to growing season, with the yield of 'Hogammi' showing a greater reduction compared with that of 'Jinyulmi'. In addition, we found that the higher shading level also significantly reduced yields. Compared with the storage root formation and storage root actively swelling stages, shading treatments during the storage root swelling stage significantly affected yield reduction in both varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.3
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• pp.254-261
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• 2012

To reduce the injury by continuous cropping of sweet potato (Ipomoea batatas (L.) Lam.), the farmer's plant and virus-free plant were cultivated with the density of $70{\times}25cm$ (June 10, 2011) in continuous cropping soil (CCS) and subsoiling reversion soil (SRS). Fertilizer was applied at the rates of 55-63-156 $kg\;ha^{-1}$ ($N-P_2O_5-K_2O$) and 10 $ton\;ha^{-1}$ of cattle manure in CCS, and it was applied the 50% increased cattle manure compost and nitrogen in DRS. Symptoms of viral infection were revealed in the farmer's plant at 30 days after planting, but there were no symptoms in virus-free plant. The yield of virus-free plant was more increased 15% and 10.5% than that of farmer's plant in DRS and CCS, respectively. The yield of sweetpotato in SRS was more increased 8.8% and 3.2% in farmer's plant and virus-free plant compared to CCS, respectively. In DRS, the rate of marketable tuber of virus-free plant was increased by 80% compared to the farmer's plant (60.1%). The virus-free plant was produced the tuber with more brilliant peel color and well-formed shape compared to the farmer's plant. The increased yield of virus-free plant and in SRS soil condition showed a positive relationship (p=0.05) with the number of leaf per plant at 30 days and the number of branch per plant at 120 days after planting. The results showed that the early growth after planting was very important for the development of storage root. Therefore, the deep-subsoil reversion and cultivation of virus-free plant could be reduced the injury by continuous cropping of sweet potato, and increased farm income.