Jamali, S. (2016) Biological control of Phytophthora root and crown rot of Pistachio using Trichoderma spp. and investigation of some biocontrol mechanisms. Masters thesis, University of Zabol.
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Abstract
Phytophthora root and crown rot is a serious disease of pistachio trees that causes economic loss to pistachio orchards. Biological control of the disease by fungal biocontrol agents is effective method for disease control. In present study, the effect of 16 isolates of T. harzianum, T. aureoviride, T. asperellum, T. koningii, T. virens, T. longibrachiatum and T. crassum were studied on radial growth and zoospore production of Phytophthora drechsleri (the causal agent of Phytophthora root rot of pistachio). The concentration of 20 and 30 % of culture filtrate showed the highest inhibitory effect on radial growth of P. drechsleri (Pd). T. harzianum 136 (Th-136) and T. harzianum 8279 (Th-8279) with 85 and 88 % respectively, had the highest inhibitory effect on radial growth of Pd. Ten percent concentration of culture filtrates of Th-136 and Th-8279 isolates, inhibited of zoospore production completely (100%). In volatile metabolites test, Th-8279 with 93% of inhibitory effect, showed the highest effect on radial growth. Using of Phytophthora –hyphe in medium as carbon source, increased activity of β 1,3 glucanase and cellulase in all isolates compared with glycerol. Th-8279 showed the highest activity of two enzymes with significant difference compared with other isolates. In laboratory studies, Th-8279 and Th-136 had the highest effect on Pd growth. In greenhouse tests, effect of Th-8279 and Th-136 were assessed on Phytophthora root rot of Sarakhs and Badmai zarand (susceptible and tolerant of pistachio rootstocks to Phytophthora). Trichoderma isolates were inoculated on pistachio rootstocks roots before the pathogen. The results showed that inoculation of two Trichoderma isolates can increase shoot and root dry weight, stem diameter and height, leaf area and content of chlorophyll compared with the control. Th-8279 and Pd interaction treatment increased level of the above criteria compared with Pd treatment. Root colonization by Pd reduced in presence of Trichoderma isolates especially in Th-8279. Mixture of two Trichoderma isolates had no significant effect of root colonization by the pathogen. Inoculation of Trichoderma isolates alone or with Pd, increased activity of β 1,3 glucanase and cellulase in pistachio rootstocks. The highest and lowest activity of the enzymes was observed in Th-8279 and isolates mixture treatments, respectively. Concentration of P, K, Ca, Mg, Fe, Cu, Zn and Mn increased in Trichoderma and its interaction with Pd treatments. Th-8279 showed the highest effect on shoot and root concentration of nutrient elements. Overally, results of the present study showed that inoculation of Th-8279 and Th-136 can control the Phytophthora root rot of pistachio by positive changes in growth, nutrition and biochemical criteria.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Soil born disease, Hydrolytic enzymes, Gummuosis |
| Subjects: | Q Science > QK Botany |
| Depositing User: | admin admin1 admin2 |
| Date Deposited: | 06 May 2017 08:25 |
| Last Modified: | 06 May 2017 08:25 |
| URI: | http://eprints.uoz.ac.ir/id/eprint/1279 |
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