• Research in Plant Disease
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• v.9 no.2
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• pp.57-63
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• 2003

Clubroot disease of curcifer crops caused by Plasmodiophora brassicae had been first reported in 1928 in Korea, and maintained mild occurrence until 1980s. Since 1990s the disease has become severe in alpine areas of Kyonggi and Kangwon, gradually spread to plain fields throughout the country, and remains as the great-est limiting factor for its production. Researches on the disease has begun in late 1990s after experiencing severe epidemics. Survey of occurrence and etiological studies have been carried out, particularly, on the pathogen physiology, race identification, quantification of soil pathogen population, and host spectrum of the pathogen. Ecology of gall formation and its decay, yield loss assessment associated with time of infection, and relationships between crop rotation and the disease incidence was also studied during late 1990s. In studies of its control, more than 200 crucifer cultivars were evaluated for their resistance to the disease. Lime applica-tion to field soil was also attempted to reduce the disease incidence. Resistant radish and welsh onion were recommended as rotation crops with crucifers after 3-year field experiments. However, so for, most studies on clubroot disease in Korea have been focused on chemical control. Two fungicides, fluazinam and flusulfamide, were selected and extensively studied on their application technologies and combination effects with lime application or other soil treatment. To develop environmentally-friendly control methods, solar-disinfection of soil, phosphoric acid as a nontoxic compound, and root-parasiting endophytes as biocontrol agents were examined for their effects on the disease in fields. In the future, more researches are needed to be done on development of resistant varieties effective to several races of the pathogen, establishment of economically-sound crop rotation system, and improvement of soil-disinfection technique applicable to Korean field condi-tion, and development of methodology of pretreatment of fungicides onto seeds and seedbeds.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.1
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• pp.72-76
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• 1983

Absorption pattern and sensitivity of radishes to boron were compared with different boron treatment: soil application, foliar spray and no boron application. Six radish cultivars were planted on April 7 and harvested on June 23. Borax 1.5 Kg per 10 a was applied to soil before seeding and the 150 litters of 0.5 ppm solution with bolic acid was sprayed on leaves 3 times during the growing period. Boron content in plant was markedly increased by the soil application but no significant difference in boron contents in plants was observed between foliar spray and no application, presumably because of the insufficient dose of foliar spray. The darkening rot in root, a boron deficiency, was negligible in radishes grown in soil application plots whereas a relatively higher percentage of boron deficient plant was found from foliar spray or no application plots. The appearance of root darkening rot occurred at the rapid root enlargement stage, apparently from 55 days to 65 days after seeding. The boron contents in plants of soil application plots slightly increased at this stage while those of no boron application and foliar spray decreased. This obviously verified that boron deficiency should cause root rots showing highly significant relationship.

• Korean Journal of Environmental Agriculture
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• v.2 no.1
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• pp.13-17
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• 1983

The influence of planting time and age of reclaimed fields on the contents of heavy metals in vegetable crops in suburban areas was investigated. Investigated crops were 4 radish cultivars, Chinese cabbage, spinach, Garland chrisanthemum, and Welsh onion. Cd, Pb, Cu, and Zn were analyzed. The results obtained were as follows. 1) For radishes except Altari-mu and Welsh onion, the highest concentrations of heavy metals were recorded in roots whereas, for Chinese cabbage and Garland chrisanthemum, the highest concentration was appeared in leaves. 2) For lettuce, radishes, and spinach, the lowest concentrations of heavy metals were recorded in winter and the concentrations were the same between spring and autumn. 3) In lettuce difference of concentrations of heavy metals were not appeared between field age after reclamation with sewege sludge. 4) The concentrations of heavy metals observed was not harmful to human health.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.415-423
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• 2018

The aim of this study was to evaluate the individual glucosinolate (GSL), total phenol, total flavonoid, and vitamin C content, and antioxidant activity under various light quality condition, mainly focusing on red (R) to far-red (FR) light ratios in three Brassica sprouts (radish, Chinese cabbage, and broccoli). Three R/FR ratio of 0.6, 1.3, and 2.0 were exposed to 5-day old sprouts for 48 h in a controlled environment, and the targeted phytochemical contents and antioxidant activities were compared with three separate control plot of dark, fluorescent, and red:blue 8:2 conditions. Total GSL content was highest in broccoli among the cultivars throughout the respective treatments, and increased with the increasing of R/FR ratio in the broccoli sprouts, while the content showed non-significant results in the Chinese cabbage sprouts. The progoitrin, a major GSL in Chinese Cabbage and broccoli, content decreased by upto 38% and 69%, respectively, with decreasing the R/FR ratio compared to the control plots (fluorescent, red:blue 8:2, and dark condition). The contents of phenol, flavonoid, and vitamin C were lowest in dark condition in all the three Brassica sprouts. The total phenol content and antioxidant activities increased with decreasing the R/FR ratio in all the Brassica sprouts, while total flavonoid and vitamin C content showed different patterns depending upon the Brassica sprouts. These results suggest that additional use of FR is expected to improve the functional quality of Brassica sprouts in different ways.

• Research in Plant Disease
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• v.29 no.4
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• pp.363-376
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• 2023

Alternaria black spots or blights in cruciferous crops have been devastating diseases worldwide and led to economic losses in broccoli, Chinese cabbage, kale, radish, rapeseed, etc. These diseases are caused by different Alternaria spp., including A. brassicae, A. brassicicola and A. raphani transmitted from infected seeds or insect vectors. Efforts to excavate disease resistance traits of cruciferous crops against Alternaria black spots or blights have been demonstrated. Genetic resource of disease resistance was investigated in the wild relatives of cruciferous crops, and different cultivars were screened under different inoculation conditions. Development of the disease-resistant lines against Alternaria black spots or blights was also tried via genetic transformation of the cruciferous crops using diverse plant defence-associated genes. Plant immunity activated by pre-treatment with chemicals, i. e. β-amino-n-butyric acid and melatonin, was suggested for reducing Alternaria black spots or blights in cruciferous crops. The disease resistance traits have also been evaluated in model plant Arabidopsis originating from different habitats. Various plant immunity-related mutants showing different disease responses from wild-type Arabidopsis provided valuable information for managing Alternaria black spots or blights in cruciferous crops. In particular, redox regulation and antioxidant responses altered in the Alternaria-infected mutants were discussed in this review.