تأثیر دو جدایه Trichoderma harzianum بر پارامترهای رشدی و تغذیه ای دو پایه پسته آلوده به پوسیدگی فیتوفتورایی ریشه

Pistachio Phytophthora root rot caused by Phytophthora drechsleri is one of the most important diseases of pistachio trees. One of the procedures to control this disease is to use Trichoderma species. In the present research, the effects of Trichoderma harzianum-136 and Trichoderma harzianum-8279 were evaluated on Phytophthora root rot on two pistachio rootstocks , Sarakhs and Badami-Zarand. The Trichoderma isolates highly inhibited from the growth of P. drechsleri in the laboratory tests. The results revealed that impregenation with both isolates of Trichoderma in absent of P. drechsleri increased shoot and root dry weight, stem diameter, height and leaf area of leaves compared to thecontrol.The influence of T. harzianum-8279 was greater than T. harzianum-136 in the most of the traits. In Sarakhs pistachio, the inoculation with P. drechsleri alone caused 48, 60, 27, 22, 31 and 37 percent reduction of above criteria compared to the control, while the reduction of the above traits in Badami-Zarand pistachio was 14, 28, 13, 10 and 4%. respectively, indicating a higher tolerance of Badami-Zarand rootstock to P. drechsleri. The interaction of Trichoderma isolates and P. drechsleri in Sarakhs pistachio significantly increased the traits compared to inoculation with P. drechsleri alone. While in Badami-Zarand pitachio, only shoot and root dry weights showed a significant difference in comparison with inoculation with P. drechsleri alone. Trichoderma harzianum-8279 was more effective than T. harzianum-136 on the above parametres. Phytophthora drechsleri could colonize Sarakhs pistachio seedlings up to 85%, while in the present of T. harzianum-136 and T. harzianum-8279 isolates its colonization percentage decreased to 60 and 51%., which showed a decrease of 29% and 40%, respectively. impregenation of pistachio seedlings with Trichoderma isolates increased the concentration of P, K, Ca, Mg, Fe, Cu, Zn and Mn in pistachio rootstocks and the effect of T. harzianum-8279 was higher than T. harzianum-136. Inoculation of pistachio seedlinds with P. drechsleri decreased the concentration of mineral nutreints which this reduction was significant in Sarakhs pistachio. In general, the results of the present research showed that impregenation of pistachio seedlings with Trichoderma isolatesdecreased the severity of Phytophthora root rot of pistachio seedlings, especially in sensitive rootstocks, by improving the growth and nutritional parameters and decreasing the colonization percentage of the pathogen in the roots.