Browsing by Author "Polat, Zuhtu"

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Comparative Aggressiveness and Fungicide Sensitivity of Phytopythium vexans and P. litorale Associated with Kiwifruit Vine Decline in Turkiye
(John Wiley & Sons Ltd, 2025) Polat, Zuhtu; Gultekin, Mehmet Akif; Ozer, Goksel; Turkkan, Muharrem; Dervis, Sibel
Background: Kiwifruit vine decline syndrome (KVDS) is an economically critical disease threatening production in Turkiye. The oomycetes Phytopythium vexans and P. litorale are increasingly implicated, but their comparative roles and effective management remain poorly understood, creating an urgent need for sustainable control strategies. This study aimed to (i) compare the virulence of these two species and (ii) evaluate the in vitro versus in vivo efficacy of key fungicides to identify reliable control strategies. Results: Pathogenicity assays revealed that P. litorale was significantly more aggressive, causing severe disease (Disease Severity Index, DSI > 70%), whereas P. vexans induced only moderate symptoms (DSI < 42%). A critical disconnect was observed between laboratory and greenhouse fungicide performance. For instance, oxathiapiprolin, which was highly potent in vitro (EC50 = 0.001169-0.006158 mu g mL(-1)), provided only moderate disease control in vivo. Conversely, pyraclostrobin-based fungicides delivered superior protection against the highly aggressive P. litorale, reducing the DSI to a range of 20.83-21.88% and significantly enhancing root biomass. Conclusion: This study establishes P. litorale as a highly aggressive pathogen in KVDS etiology and demonstrates that in vitro data alone are misleading for predicting fungicide field performance. Pyraclostrobin-based fungicides are identified as the most effective candidates for managing KVDS caused by P. litorale. These findings underscore the necessity of integrating in vivo validation in screening protocols and adopting species-specific management approaches, providing a critical roadmap for developing sustainable solutions against this devastating disease. (c) 2025 Society of Chemical Industry.
Pathogen Identification And Resistance Screening Of Fusarium Basal Rot İn Taşköprü Garlic İn Türkiye
(Wiley, 2024) Polat, Zuhtu; Besirli, Gulay; Dervis, Sibel; Ozer, Goksel; Sezer, Sati Mehmet; Ipek, Mehmet; 16.01. Department of Organic Agriculture / Organik Tarım Bölümü; 16. School of Vocational Higher School of Kızıltepe/ Kızıltepe Meslek Yüksekokulu; 01. Mardin Artuklu University / Mardin Artuklu Üniversitesi
Fusarium basal rot (FBR), caused by Fusarium spp., is a significant threat to garlic production globally, including in T & uuml;rkiye, where the unique Ta & scedil;k & ouml;pr & uuml; garlic is highly valued. This study investigated the diversity and aggressiveness of 77 Fusarium isolates obtained from disease surveys of FBR in Ta & scedil;k & ouml;pr & uuml; garlic and evaluated the yield and resistance of 20 garlic accessions, including 18 local landraces, the locally developed 'Ta & scedil;k & ouml;pr & uuml; 56', and the commercial Chinese variety 'ASCG'. Molecular identification using translation elongation factor 1-alpha (TEF1) and second largest RNA polymerase II B-subunit (RPB2) genes revealed F. oxysporum (67.5%) as the dominant species, followed by F. proliferatum (15.6%), F. solani (9.1%), F. redolens (5.2%) and F. clavum (2.6%), respectively. All isolates were pathogenic, but aggressiveness varied, with F. solani being the most aggressive, followed by F. redolens and F. oxysporum. While 'ASCG' exhibited the highest yield (3.15 ton/ha), it was highly susceptible to FBR (DSI = 97.50%). Conversely, the landrace ASTK2 displayed the highest resistance (DSI = 53.13%), but lower yield. Promisingly, several Ta & scedil;k & ouml;pr & uuml; landraces, such as ASTK6 and ASTK13, demonstrated both moderate resistance and promising yield potential. Surprisingly, 'Ta & scedil;k & ouml;pr & uuml; 56', despite being a locally developed variety, exhibited high susceptibility to FBR (DSI = 93.75%) and did not outperform many landraces in terms of yield. This study provides the first reports of F. redolens and F. clavum infecting garlic in T & uuml;rkiye, and the first molecular characterisation of F. solani as a garlic pathogen in the country, highlighting the potential of local landraces for breeding FBR-resistant, high-yielding cultivars.