تعيين مشخصات بيولوژيكي و بيمارگري عامل پوسيدگي خشك غده سيب زميني در اصفهان

چكيده انگليسي :

Biological and Pathological Characterization of Causal Agent of Potato Tuber Dry Rot in Isfahan Seyed Amir Taha Beheshti Amir beheshti48@yahoo com January 11 2014 Department of Plant Protection Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiM Bahar Professor Mbahar@cc iut ac irAbstractPotato Solanum tuberosum L belongs to solanaceae is one of the most important sources of human food Itranks fifth in world production after wheat rice maize and barley and has become an important vegetable cropin Iran recently Among the potato diseases Fusarium dry rot is the most destructive disorder in storage whichcauses 10 20 crop losses nationwide including Isfahan Therefore obtaining appropriate information about themost common Fusarium species causing potato dry rot mode of its pathogenisity in storage conditions and thepossibility of disease control using fungicides are required for efficient disease management The mainobjectives of this study were to identify the species of Fusarium sp currently cause potato dry rot in Isfahan determination the appropriate conditions for development of the disease and find a way to control the dry rotprogress during potato storage The potato tubers showing Fusarium dry rot symptoms were collected fromdifferent suppliers in Isfahan and cultured on Potato Dextrose Agar PDA In total 61 Fusarium isolates wereobtained from the symptomatic tubers examined Based on morphological characteristics 30 isolates wereidentified as F solani 18 as F oxysporum 8 as F chlamydosporum and 3 as F semitectum of which F solaniwas the most common species in Isfahan PCR reactions were performed to validate speciation of the candidateisolates Molecular identification of F solani and F oxysporum was confirmed using specific primer pairsS3R S3F 491 bp and Clox2 R Clox1 F 534 bp respectively The universal primers ITS4 ITS5 were used toamplify rDNA internal transcribed spacers ITS regions for detection of F chlamydosporum and F semitectum Mixed infection of F solani and F oxysporum was also confirmed using Duplex PCR method in some infectedtubers The pathogenicity tests of the isolates on wounded tubers showed a great similarity among the symptomsinduced by the Fusarium species Both dry rot and soft rot symptoms were produced in the inoculated tubers byF solani Fusarium oxysporum and F semitectum although F chlamydosporum caused solely dry rot Thedegree of rot development in potato cultivars inoculated with the Fusarium species was various in differenttemperatures conditions Among the Fusarium species tested F solani was evaluated as the most aggressivespecies while F chlamydosporum had low potential to develop tuber rot According to the results varietiesMarfona and Agria were the most sensitive and tolerant cultivars against Fusarium species respectively Allfour Fusarium species were sensitive to fungicides namely Carbendazim and Benomyl The fungicidesensitivity tests demonstrated that Carbendazim was the most effective fungicide against F solani andF oxysporum while Benomyl was more efficient to control F chlamydosporum and F semitectum growth Theresults of this study showed that occurrence of potato dry rot has a direct relevance with storage temperature thefungal species and the variety of potato Presence of wound on tuber surface also plays an important role ininfection Considering these results it seems that use of low temperature in warehouse tolerant cultivars such asAgria and pre treatment of tubers with mixture of Benomyl and Carbendazim can be an effective strategy todecrease Fusarium dry rot losses of stored potatoes Key words Potato Fusarium dry rot Primers Fungicide

بهشتي، اميرطه

تعيين مشخصات بيولوژيكي و بيمارگري عامل پوسيدگي خشك غده سيب زميني در اصفهان

پوسيدگي خشك فوزاريومي , آغازگرها , قارچكش