• The Korean Journal of Mycology
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• v.41 no.3
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• pp.142-148
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• 2013

Sorghum (Sorghum bicolor Moench) was traditionally grown on a small scale, however, at present its cultivation is getting momentum in terms of food and animal feed crop throughtout the Korea. Grain mold symptoms of the plant were frequently observed during disease surveys in Korea from 2007 to 2009. The symptoms were highly variable. Severely infected grain was fully covered with mold and partially infected grain may look normal or discolored. Ninety isolates of Fusarium species were obtained from the diseased plants collected from several locations in the country. Among the collected Fusarium isolates, 41 were identified as Fusarium thapsinum, 23 as F. proliferatum, 12 as F. graminearum, 5 as F. incarnatum, and 3 as F. equiseti based on their morphological and cultural characteristics. Elongation factor 1 alpha gene sequences of the isolates were used for phylogenetic analysis. Analyses of the sequences revealed that the isolates were confirmed to be identical with related species of NCBI GenBank. Pathogenicity tests showed that three dominant species, F. thapsinum, F. proliferatum and F. graminearum were strongly virulent to grains of sorghum. This study is the first report of sorghum grain mold caused by Fusarium species in Korea.

• Research in Plant Disease
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• v.11 no.1
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• pp.43-47
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• 2005

To investigate control efficacy of flusulfamide GR (granule) on Chinese cabbage clubroot caused by Plasmodiophora brassicae, experiment was accomplished in field located in Gangneungshi alpine area contaminated by P. brassicae. Flusulfamide GR provided control value of 84.6% and that was statistically significant difference from standard fungicides containing untreated control. To investigate ratio of reduction of resting spore according to fungicide treatment, soil of Chinese cabbage field before and after fungicide treatment were sampled and investigated density of resting spore. Resting spore density was not uniform in soil before fungicide treatment. Therefore, to investigate control efficacy of fungicide against clubroot, investigation on resting spore density was conducted before experiment and reflected in experimental design. Flusulfamide GR and DP (dust powder) provided 64.2% and 63.7% of reduction of resting spore on field soil after fungicide treatments. This result indicated that control efficacy of the fungicides was correlated with reduction of resting spore of P. brassicae. The increasing rate in fresh weight of above-ground part of Chinese cabbage by flusulfamide DP and GR, fluazinam DP and trifloxystrobin SC (suspension concentrate) was 14.3%, 13.0%, 13.8% and 3.8%, respectively. From above result, flusulmide GR have outstanding control efficacy against clubroot of Chinese cabbage and is effectively decreasing of resting spore density in soil.

• Research in Plant Disease
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• v.12 no.2
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• pp.108-114
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• 2006

This study was conducted to elucidate the interactions among soil microorganisms in a special field where one, two or three of N, P, K fertilizers were continuously not applied for 29 years. Crop yield (barley, soybean), soil chemical properties and microflora and microfauna including nematodes, nematophagous fungi, actinomycetes, bacteria, and fungi were examined for two years. Tylenchorhynchus sp. was the most important plant-parasitic nematode (range $11{\sim}642/300 cm^3$ soil) followed by Pratylenchus sp. and Helicotylenchus sp. Among nematophagous fungi, Monacrosporium spp. was the most frequently found followed by Harposporium sp. and Cystopage sp. In general, plots treated with phosphate fertilizer yielded more, had more nematodes, bacteria and actinomycetes. In contrast, total fungal population densities including nematophagous fungi, Cystopage sp. and Harposporium sp. were in reverse; they were more abundant in the plots with lower phosphate contents. Phosphate and pH are positively correlated and two most important determining factors for the population density of soil organisms under investigation. According to correlation analysis, Ca, Mg, and $SiO_2$ contents in soil and population densities of Tylenchorhynchus sp., saprophitic nematodes, actinomycetes, and bacteria were positively correlated with pH, but were negatively correlated with fungal population densities. We hope that the study will add an additional knowledges to understand our mysterious underworld.

• Korean Journal of Plant Tissue Culture
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• v.24 no.3
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• pp.153-160
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• 1997

Cucumber mosaic virus (CMV) leads to a cause of poor crop productivity and quality. To solve this problem, we attempted to develop a virus-resistance tobacco plants by using viral coat protein (CP) gene. Transgenic tobacco plants expressing CMV CP gene were analysed by the resistance upon CMV infection. The virus-resistance was measured in $\textrm{T}_{1}$, generation by the inhibition of plant growth and the expression of the mosaic symptoms infected with CMV. The transgenic lines were divided into four groups: highly resistant, resistant, moderate and susceptible based on their growth and symptom severity. Out of 39 transgenic lines, 16 lines showed significant virus-resistance. And of resistant lines, 2 lines were designated highly resistant based on the facts that they achieved similar plant height to that of non-infected tobacco plants and showed lower disease symptom than that of other lines. The steady state level of CP RNA and coat protein level were measured by northern blot and immunoblot analysis. The CP RNA was highly accumulated in most resistant and moderate lines but barely detected in susceptible lines. The coat protein was detected in most lines regardless of their resistance to CMV. from this result, virus-resistance appeared to correlate more with CP RNA level than the level of coat protein. However, in two highly resistant lines, CP RNA level was unexpectedly low. This unexpected phenomenon need to be further investigated.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.1
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• pp.19-22
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• 2016

'Lucky one' is a new orchardgrass (Dactylis glomerata L.) variety developed by the National Institute of Animal Science (NIAS) in 2014. Four superior clones were selected and polycrossed for seed production to develope this new variety of orchardgrass. The agronomic growth characteristics and forage productivity of 'Lucky one' were examined at Cheonan from 2010 to 2011. Regional adaption trials were conducted in Cheonan, Hoengseong, Jinju, and Jeju from 2012 to 2014. 'Lucky one' showed growth habit of medium type in fall and spring. It has short flag leaf length with long upper internode. Plant height of 'Lucky one' was 3 cm more than that of control variety, 'Amba'. Its heading date was 2 days later than that of control variety 'Amba'. Characteristics such as waterlogging and disease resistance of 'Lucky one' were stronger or better than those of control variety, 'Amba', Especially, dry matter yield of 'Lucky one' (16,191 kg/ha) was increased 38% compared to that of control variety, 'Amba'(11,778 kg/ha). Nutritive feed values of 'Lucky one' appeared to be similar to those of control variety 'Amba' except in Vitro dry matter digestibility (IVDMD) and crude protein content.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.1
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• pp.15-18
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• 2016

'Onnuri 2ho' is a new orchardgrass (Dactylis glomerata L.) variety developed by the National Institute of Animal Science (NIAS) in 2014. Four superior clones were selected and polycrossed for seed production to develop this new variety of orchardgrass. The agronomic growth characteristics and forage productivity of 'Onnuri 2ho' were examined at Cheonan from 2010 to 2011. Regional adaptation trials were conducted in Cheonan, Hoengseong, Jinju and Jeju from 2012 to 2014. 'Onnuri 2ho' showed growth habit of medium type in fall and spring. It is long in length of flag leaf with medium upper internode. Plant height of 'Onnuri 2ho' was 4 cm more than that of control variety, 'Amba'. Its heading date was 4 days later than compared to control variety, 'Amba'. Characteristics such as waterlogging and disease resistance of 'Onnuri 2ho' were stronger or better than those of control variety, 'Amba', Especially, the dry matter yield of 'Onnuri 2ho' (15,814 kg/ha) was increased 34 % compared to that of control variety, Amba (11,778 kg/ha). Nutritive feed values of 'Onnuri 2ho' appeared to be similar to that of control variety 'Amba' except in Vitro dry matter digestibility (IVDMD).

• Horticultural Science & Technology
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• v.34 no.3
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• pp.355-362
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• 2016

This study was carried out to investigate the effects of rain-shelter types on growth, and fruit quality of red pepper (Capsicum annuum, 'Kemmaru') cultured in paddy. Applied rain-shelter types were outfield (control), simple rain-shelter plastic house with 2 rows (2R), simple rain-shelter plastic house with 4 rows (4R), and perfect plastic house (House). The plant height was the highest in Houses treatment. There was no difference in leaf length and width among the rain-shelter treatments. The fresh and dry weight of red pepper was high in order of House > 4R > 2R > Control. The ASTA value is irregular tendency among the treatments. Hunter's color value 'a' and 'b' was not different from among the treatments. Phytophthora blight, powdery mildew, bacterial spot were not occurred in all of treatments, and Anthracnose was only occurred in control. Mite, Microcephalothrips abdominalis, and Bemisia tabaci were not occurred in all of treatments, and aphid, Helicoverpa assulta, and virus were occurred all of treatments as same degree. Our results will provide rain-shelter cultivation of red pepper can be increase dry yield and decrease disease and insects.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.319-323
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• 2009

Strawberry is an out-crossed crop that is relatively sensitive to inbreeding, and as a result, most of breeding programmes in strawberry have been based on selection breeding where elite parents are selected from intercrossing. Also, pedigree breeding has been successfully employed in a number of instances to concentrate genes of interest. Therefore, in order to obtain inbred line having the genotype of excellent combining ability by selfing and incrossing to improve breeding efficiency of strawberry, elite varieties were self-pollinated. From the selfing line of "Benihoppe" cultivar, we selected "Wongyo 3111" having excellent horticultural traits such as plant vigor, sugar content and fruit hardness among these progenies. "Wongyo 3111" shows erect plant type, vigorous growth habit, early flower bud differentiation with 16~17 flowers per cluster. Fruits of "Wongyo 3111" are conical type having a bright red skin color, and 17.2 g in an average weight. Also that have a relatively more high sugar/acid ratio and firmness than check cultivars as sugar content of 11.3oBx, acidity of 0.50% and firmness of 21.7 g/$mm^2$. But although yield of "Wongyo 3111" is not significantly different from check cultivars, its marketable yield is remarkably lower than that of check cultivars because of poor fruit-setting under low temperature. Disease and pest reactions of "Wongyo 3111" are more sensitive to powery mildew, anthracnose and spotted spider mites than check cultivars. Therefore, "Wongyo 3111" is suitable for intermediate parent line better than as a cultivation cultivar.

• Research in Plant Disease
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• v.27 no.3
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• pp.120-127
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• 2021

Plant viruses cause significant yield losses, continuously compromising crop production and thus representing a serious threat to global food security. Tomato spotted wilt virus (TSWV) is the most harmful plant virus that mainly infects horticultural crops and has a wide host range. Reverse-transcription quantitative real-time PCR (RT-qPCR) has been widely used for detecting TSWV with high sensitivity, but its application is limited owing to the lack of standardization. Therefore, in this study, a sensitive and accurate reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) method was established for TSWV detection. Additionally, we compared the sensitivities of RT-qPCR and RT-ddPCR for TSWV detection. Specificity analysis of RT-ddPCR for TSWV showed no amplification for main pepper viruses and negative control. TSWV transcripts levels measured by RT-ddPCR and RT-qPCR showed a high degree of linearity; however, the former yielded results that were at least 10-fold more sensitive and detected lower TSWV copy numbers than the latter. Collectively, our findings show that RT-ddPCR provides improved analytical sensitivity and specificity for TSWV detection, making it suitable for identifying low TSWV concentrations in field samples.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.7-14
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• 2021

Tomato crops are highly affected by tomato diseases, and if not prevented, a disease can cause severe losses for the agricultural economy. Therefore, there is a need for a system that quickly and accurately diagnoses various tomato diseases. In this paper, we propose a system that classifies nine diseases as well as healthy tomato plants by applying various pretrained deep learning-based CNN models trained on an ImageNet dataset. The tomato leaf image dataset obtained from PlantVillage is provided as input to ResNet, Xception, and DenseNet, which have deep learning-based CNN architectures. The proposed models were constructed by adding a top-level classifier to the basic CNN model, and they were trained by applying a 5-fold cross-validation strategy. All three of the proposed models were trained in two stages: transfer learning (which freezes the layers of the basic CNN model and then trains only the top-level classifiers), and fine-tuned learning (which sets the learning rate to a very small number and trains after unfreezing basic CNN layers). SGD, RMSprop, and Adam were applied as optimization algorithms. The experimental results show that the DenseNet CNN model to which the RMSprop algorithm was applied output the best results, with 98.63% accuracy.