Identification of fungal causal agents of damping off in cucurbits in Sistan and their control by rhizosphere antagonist

Noori, M. (2013) Identification of fungal causal agents of damping off in cucurbits in Sistan and their control by rhizosphere antagonist. Masters thesis, University of Zabol.

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Abstract

The melon (Cucumis melo) is cultivation in different regions of Iran. Vine decline disease is a destructive soilborne disease of melon. Vine decline is a generic term applied to a group of diseases with similar symptoms but different causal agents. Different methods were used to decrease the disease. In addition to plant management, researches were performed on biocontrol agant to control vine decline diseases in cucurbitaceae and other plants. To identify fungi associated with root and vine decline of melon and isolation of antagomistic agents to control thiese fungi in commercial fields in different regions of Sistan sampled were collected during growing season of 2011-2012. Suspected samples were collected and transported to the laboratory. To isolate the fungi, discolored segments of roots and crowns were surface sterilized in 1% sodium hypochlorite for 1-3 min and cultured on Potato Dextrose Agar. The plates were incubated for 3 to 5 days, hyphal tips or spores of the fungi were transferred to new PDA plates and were identified based on morphological characteristics. The pathogencity test was performed using inoculum of fungal isolates. The test was done in the greenhouse. In the study, Rhizoctonia solani, Macrophomina phaseolina, Monosporascus cannonballus, Fusarium proliferatum and Fusarium solani were identified as fungal causal agents of damping off in melon in Sistan. In the second step, the soil sampeles from the rhizosphere of infected and non-infected melon were plated on Nutrient Agar and McFadden & Sutton’s RB-S-F. Bacillus sp and Trichoderma sp were separated. In the third step, Dual culture was used to study the antagonist effects of the T. harzianum, isolates of Bacillus subtilis and Bacillus tequilensis on mycelial growth of R. solani, M. phaseolina, M. cannonballus, F. proliferatum and F. solani in vitro. The ability of the isolate of B. subtilis and T. harzianum in reduction of the incidence of melon crown and root rot in a glasshouse was proven. Analysis of variance was performed and the means were compared using Duncan’s multiple Range Test at p<0.05. The greenhouse results revealed that T. harzianum decreased incidence of melon crown and root rot that were infected with R. solani, F. proliferatum, F. solani, M. phaseolina and M. cannonballus to 18/3, 42, 30/3, 18/3 and 20 percent while B. subtilis B1 and, B. subtilis B8 infected with R. solani, F. proliferatum, F. solani, M. phaseolina and M. cannonballus the disease was decreased to 0 and 1/6, 29 and 34/7, 17 and 26/3, 20 and 18/3 and 13/3 and 16/6 percent respectively.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Antagonists, damping off, melon, vine crops
Subjects: Q Science > QK Botany
Depositing User: admin admin1 admin2
Date Deposited: 26 Oct 2016 10:26
Last Modified: 26 Oct 2016 10:26
URI: http://eprints.uoz.ac.ir/id/eprint/924

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