Document Type : Original Article
Author
Plant Pathology Research Institute, Agricultural Research Center, 12619, Giza, Egypt
Abstract
Eleven fungal isolates were isolated from naturally infected chickpea roots collected from different locations in. New Valley governorate. The isolated fungi were purified and identified as Rhizoctonia solani (5 isolates), Fusarium solani (4 isolates) and Sclerotinia sclerotiorum (2 isolates). The isolated fungi proved their pathogenicity on cv. Giza 3. Response of chickpea cvs. Giza 1, 2, 3, 4, 88, 195 and 531 to infection by the tested fungi was significantly varied. Giza 1 was the most resistant one followed by Giza 531, while the other tested cvs. were highly susceptible. Seven biocontrol agents, namely Bacillus subtilis, B. megaterium, B. cereus, Trichoderma viride, T. harzianum, Aspergillus sp., Penicillium sp. isolated from chickpea rhizosphere, were tested for their antagonistic action against the tested pathogens. B. subtilis isolate BSMl, B. megaterium isolate TVM5, T. viride isolate TVM2 and T. harzianum isolate THM4 were the most antagonistic ones to the tested fungi in vitro, while the other isolates were moderate or weak antagonists. The most antagonistic isolates as well as the commercial biocide Rhizo-N were applied as seed treatment for controlling damping-off, root and/or stem rot diseases caused by the tested fungi under greenhouse conditions. The obtained data showed that all tested antagonistic isolates were able to cause significant reduction of damping-off, root and/or stem rot diseases in chickpea plants. T. viride (isolate TVM2) and B. megaterium (isolate BMM5) proved to be the most effective isolates for controlling the diseases. Under field conditions, these antagonistic isolates were used as seed treatment of resistant cultivar Giza 1 and sown in three sowing dates to be work of an integrated control program to reduce spread of damping-off, root and/or stem rot diseases under field conditions. The obtained data indicated that all the tested antagonistic isolates significantly reduced damping-off, root and/or stem rot. T. viride (isolate TVM2) and B. megaterium (isolate BMM5) recorded the highest reduction of damping-off, root and/or stem rot in all sowing dates. Sowing of treated seeds with bioagents in first of November gave the highest protection against root diseases in chickpea. The reduction in damping-off, root and/or stem rot severity was significantly reflected on the produced seed yield. In this respect, seeds previously treated with T. viride (TVM2) produced the highest seed yield in all sowing dates followed by seed treated with B. megaterium (TVM5). First of November was the best sowing date to reduce these diseases and to increase seed yield/fed. On the other hand, the antagonistic isolates isolated from chickpea rhizosphere, were most active than the commercial biocide Rhizo-N in reducing chickpea root diseases and increase of seed yield in greenhouse and field conditions.
Keywords
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