• Title/Summary/Keyword: rotted onion

Search Result 3, Processing Time 0.015 seconds

Characterization of Bacteria Isolated from Rotted Onions (Allium cepa) (양파 부패병변에서 분리한 세균의 특성)

  • Lee Chan-Jung;Lim Si-Kyu;Kim Byung-Chun;Park Wan
    • Microbiology and Biotechnology Letters
    • /
    • v.33 no.4
    • /
    • pp.248-254
    • /
    • 2005
  • One hundred thirty nine bacteria were isolated from rotten onions collected from main producing districts, Chang-Nyung, Eui-Ryung, and Ham-Yang in Korea. The $18\%$ (25 strains) of bacterial isolates have carboxymethylcellulase (CMCase) activity and the $53\%$ (74 strains) have polygalacturonase (PGase) activity. Thirty one among randomly selected 45 strains of PGase producing bacteria have pathogenicity to onions. The isolates were classified into Pseudomonas sp. (18 strains), Bacillus sp. (11 strains), Yers-inia sp. (7 strains), and others (9 strains) on the basis of FAMEs patterns. Eighteen strains of Pseudomonas sp. were mainly divided into three cluster in the dendrogram and only the two clusters of them showed pathogenicity to onions. CMCase and PGase activities of Pseudomonas sp. weaker than those of Bacillus sp.. However, the pathogenicity of pseudomonas sp. to soften onions was stronger than that of Bacillus sp. Inoculation of $10^{2}$ cfu of Pseudomonas sp. gives rise to softening of onions. Pseudomonas sp. was identified as Pseudomonas gladioli by biochemical and physiological characteristics. P. gladioli is the first reported bacterium as a pathogen of onion in Korea. In low temperature, P. gladioli showed better growth and higher PGase activity than those of Bacillus sp. identified as Bacillus subtilis. And pH 9.0 is optimal pH for PGase activity of B. subtilis while that of P. gladioli is pH $5.0\∼6.0$ which is the acidity of onions. Taken together, P. gladioli may be a main pathogene of onion rot during the cold storage condition.

Effect of Paddy and Upland Conditions on Yield and Storage of Onion Bulbs (논밭 재배지 조건에 따른 양파 채종용 모구의 수량 및 저장력 변화)

  • Cho Sang-Kyun;Lee Eul-Tai;Oh Young-Jin;Choi In-Hu;Kim Young-Jin;Kim Jung-Gon
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.51 no.5
    • /
    • pp.401-407
    • /
    • 2006
  • This study was conducted to investigate the effect of onion cultivation under paddy and upland condition on the yield and storage of onion bulbs. In comparison of soil conditions, nitrogen, phosphate, potassium content and average temperature in upland condition were higher than those of paddy condition, but calcium, magnesium, sodium and water content in paddy condition were higher than those of upland condition. The growth of aerial part was better in upland cultivated condition. It showed that bulb formation in paddy cultivated condition was faster during in early growth stage, but was slower during in late growth stage. Average bulb size and weight were higher in upland cultivated condition, but dry weight per 100 g fresh weight and bulb hardness were higher in paddy cultivated condition. Sugar contents, inorganic compounds, nitrogen, phosphate and potassium content of onion were higher in upland cultivated condition, but calcium, magnesium and sodium content of onion were higher in paddy cultivated condition. In distribution of onion bulb size, most of large sized onions were produced in upland cultivated condition. Average bulb production for seed harvesting were $63{\sim}70%$ higher in paddy cultivated condition than that of upland cultivated condition. The rotted rate of onion was about $27.2{\sim}34.6%$ in paddy, $37.5{\sim}51.4%$ in upland cultivated condition respectively, showed favorable result as the difference of $8.7{\sim}24.2%$ in paddy cultivated condition.

Sclerotium Rot of Onion Caused by Sclerotium rolfsii (Sclerotium rolfsii에 의한 양파 흰비단병)

  • Kwon, Jin-Hyeuk;Kim, Hee-Dae;Choi, Ok-Hee;Kwak, Youn-Sig;Lee, Yong-Hwan;Shim, Hong-Sik
    • Research in Plant Disease
    • /
    • v.17 no.2
    • /
    • pp.222-224
    • /
    • 2011
  • The sclerotium rot of onion (Allium cepa L.) was occurred sporadically in the farmer's fields at Daehap, Changnyeong in Korea. The typical symptom was water-soaking on the bulb, stem and leaves and then rotting, wilting, blighting and the infected plants eventually were rotted and died. The sclerotia were globoid, 1-3 mm, and white to brown. The optimum temperature for mycelial growth and sclerotial formation on PDA was $30^{\circ}C$. The hyphal width was 4-9 ${\mu}m$. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. On the basis of mycological characteristics, ITS rDNA sequence analysis, and pathogenicity, this fungus was identified as Sclerotium rolfsii Saccardo. To our knowledges, this is the first report of sclerotium rot on onion caused by S. rolfsii in Korea.