التفاصيل البيبلوغرافية
| العنوان: |
Comparative Survival of Sclerotia of Sclerotinia minor and S. sclerotiorum. |
| المؤلفون: |
Wu, B. M.1, Subbarao, K. V.1 kvsubbarao@ucdavis.edu, Liu, Y.-B.2 |
| المصدر: |
Phytopathology. Jun2008, Vol. 98 Issue 6, p659-665. 7p. |
| مصطلحات موضوعية: |
*SCLEROTINIA minor, *SCLEROTINIA sclerotiorum, *SOIL moisture, *VALLEYS, *LETTUCE, *DATA analysis |
| مصطلحات جغرافية: |
SAN Joaquin Valley (Calif.), CALIFORNIA |
| مستخلص: |
Survival of sclerotia of Sclerotinia minor and S. sclerotiorum was compared in irrigated fields during the summer in two major lettuce production areas in California. More than 50% sclerotia of S. sclerotiorum compared with 4 and 35% of S. minor remained viable after 24 weeks of burial at 15 and 5 cm depths, respectively, in the San Joaquin Valley while >80% of sclerotia survived in the Salinas Valley for both species. The results explain in part the lower infections from S. minor in the San Joaquin Valley. To identify factors that contribute to the rapid decline in the viability of sclerotia, the effects of soil moisture, temperature, and oxygen levels were studied in laboratory. More than 90% of scierotia of both species survived for at least 3 months in sterilized dry soils at temperatures between 15 and 40°C. Soil moisture did not affect survival at 15 and 25°C. At 35°C, however, survival rates were significantly lower at high (-0.3 to -0.01 MPa) water potential than at low (<-1.0 MPa) water potential. Incubation under ultralow oxygen concentration (0.01%) significantly reduced survival of sclerotia in nonautoclaved moist soils at 25°C, with less than 2% sclcrotia surviving over 4 weeks compared with about 45% sclerotia surviving at the ambient oxygen level (2 1%). The combination of high temperature, high soil moisture, and reduced oxygen in irrigated fields contribute to the lower survival of both Scierotinia species and the responses of the two species to these conditions shape their relative geographical distribution. [ABSTRACT FROM AUTHOR] |
| قاعدة البيانات: |
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