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Öğe Analysis of Polygalacturonase Enzyme Production in Isolates of Botrytis cinerea Sensitive to Different Fungicides Used in Vineyards(Wiley, 2010) Özer, Nuray; Köycü, Nagehan Desen; Delen, NafizReduction of mycelial growth and spore germination of Botrytis cinerea, the causal agent of grey mould, are common criteria to determine the sensitivity of this fungus to fungicides. In this article, the influence of nine different fungicides on polygalacturonase (PG) activity and mycelial dry weight (MDW) was analysed on culture filtrates from B. cinerea, obtained from grapes. All fungicides except triadimenol and tebuconazole inhibited MDW of isolates <50%. Cyprodinil + fludioxonil, myclobutanil and imazalil inhibited PG activity more than 50%. Fenhexamid had a lower inhibitory effect (<50%) on PG activity. Procymidone and pyrimethanil induced both PG activity and isoenzyme banding profile of isolates sensitive to these fungicides. This study provides a new additional tool for determining sensitivity to fungicides and monitoring the effect of fungicide resistance management policies.Öğe Batı Karadeniz bölgesi mısır ekiliş alanlarında koçan çürüklüğü etmeni Fusarium verticilloides'in zearalenone oluşturma durumu üzerinde araştırmalar(2012) Büyük, Orhan; Özer, Nuray2009-2010 yılları arasında yürütülen bu çalışmanın amacı, koçan çürüklüğüne neden olan Fusarium verticilloides etmeninin oluşturduğu zearalenone (ZEA) toksin miktarını belirlemek olmuştur. Bu amaçla, Bartın, Bolu, Düzce ve Zonguldak illeri mısır ekiliş alanlarından toplanan 70 mısır koçan örneğindeki toksin miktarları HPLC cihazı ile tespit edilmiştir. Elde edilen sonuçlara göre ZEA toksin miktarı ortalama 828.47 ppb olarak saptanmıştır. Çalışmamız sonucunda elde edilen ZEA miktarları, ülkemiz ve AB'nin ZEA için belirlediği maksimum limitlerin üzerinde bulunmuştur. Farklı illerden toplanan mısır örneklerinde tespit edilen ZEA toksin miktarları arasında herhangi bir farklılık belirlenmemiştir.Öğe Bazı Üzüm Çeşitlerinin Doğal Enfeksiyon Koşullarında Mildiyö Hastalığına Karşı Reaksiyonları(2022) Doğu, Duygu Mermer; Zobar, Damla; Doğu, Koray; Özer, Nuray; Bayraktar, HarunBağcılığının önemli sorunlarından biri Plasmopara viticola tarafından neden olunan mildiyö hastalığıdır. Bu çalışmanın amacı bazı üzüm çeşitlerinin doğal enfeksiyon koşullarında mildiyö hastalığına karşı reaksiyonlarını tespit etmektir. Bu amaçla Tekirdağ Bağcılık Araştırma Enstitüsü bağ alanlarında 2016 ve 2017 yıllarında mildiyö hastalığı şiddeti (%) dikkate alınarak 21 üzüm çeşidi değerlendirilmiştir. Çalışma sonucunda, çeşitlerin hastalık şiddetinin yıllara göre değişkenlik gösterdiği ve çeşitler arasında önemli derecede farklılıklar olduğu belirlenmiştir. Ancak değerlendirmelerin yapıldığı yıllarda çiçeklenme döneminde yeterli yağışların olmaması nedeniyle çok sayıda çeşitte hastalık şiddeti yüksek olmamıştır. 2016 ve 2017 yıllarında en yüksek hastalık şiddetleri sırasıyla %14 ve %10.25 ile 'Cabernet Sauvignon'’da görülmüştür. 'Isabella' ise en düşük hastalık şiddetini sergilemiş, söz konusu yıllarda hastalık şiddetleri sırasıyla %0 ve %0.50 olmuştur. Bu çeşidi 2016 ve 2017 yıllarında sırasıyla %0.75 ve %0.25’lik hastalık şiddetleri ile 'Semillon', %1.25 ve %1.00’lik hastalık şiddetleri ile 'Yapıncak', %0.75 ve %1.50’lik hastalık şiddetleri ile 'Reçel Üzümü' izlemiştir. Çeşitlerin tane rengi, olgunlaşma dönemi ve yaprak tüylülük durumu gibi bazı ampelografik özellikleri ile mildiyö hastalığı şiddeti arasında bir ilişki olmadığı görülmüştür. Bu çalışma 17 üzüm çeşidinin ('Sultani Çekirdeksiz', 'Çavuş', 'Müşküle', 'Barış', 'Yalova İncisi', 'Bozbey', 'Cardinal', 'Reçel Üzümü', 'Tekirdağ Çekirdeksizi', 'Güzgülü', 'Yapıncak', 'Chardonnay', 'Semillion', 'Gamay', 'Kalecik Karası', 'Papaz Karası' ve 'Cinsaut') doğal enfeksiyon koşullarında mildiyö hastalığına karşı duyarlılıkları yönünden ilk bulguları içermektedir.Öğe Biological control of onion basal rot disease using Trichoderma harzianum and induction of antifungal compounds in onion set following seed treatment(Elsevier Sci Ltd, 2008) Coşkuntuna, Arzu; Özer, NurayTrichoderma harzianum KUEN 1585 (commercial product, Sim(R)Derma) was tested to determine its effect on the mycelial growth of Fusarium oxysporum f.sp. cepae (FOC) in dual culture and its control of basal rot disease in pot- and field-grown onion sets. The abilities of T harzianum to induce the production of antifungal compounds in sets and to increase onion set diameter were also studied. In pot experiments, where the soil was inoculated with a pathogenic isolate of FOC, seeds were coated with T harzianum at the dosage of 10 g kg(-1) seed. In field experiments, seeds coated with T harzianum were sown in soil naturally infested with the pathogen. T harzianum inhibited mycelial growth of the pathogen in vitro. Seed treatment with T harzianum decreased disease incidence comparable to the imidazole fungicide, prochloraz in both pot and field experiments. It also enhanced bulb diameter of sets, especially in the pot experiment. Extracts from onion sets grown from treated seeds under both conditions were fractionated by thin-layer chromatography for their antifungal compounds. Most of the fractions obtained from the sets of T harzianum-treated seeds showed high antifungal activity against the pathogen. This study suggests the possible role of T harzianum in the induction of antifungal compounds against F. oxysporum f. sp. cepae in onion sets. (C) 2007 Elsevier Ltd. All rights reserved.Öğe Crossing of Alphonse lavallee and regent grape cultivars for downy mildew resistant genotypes. 1. seed germination and seedling growth(Centenary University, 2019) Uzun, Halil İbrahim; Özer, Nuray; Akkurt, Murat; Özer, Cengiz; Aydın, Serkan; Aktürk, BurakCrossing for disease resistance of grape cultivars is one of the main interests of grape breeding. Downy mildew is one of the destructive diseases of grapevines. V. vinifera has superior characteristics for wine or fresh consumption but mildew sensitive. Vinifera grapevines are cross with American wild grapes to obtain resistant cultivars. But some hybrid grapes have low seed germination. The main goal of this study was to develop hybrid table grape F1 offsprings with resistance to downy mildew disease and to test seed characteristics of them. Alphonse Lavalle (susceptible) and Regent (resistant) grape cultivars were crossed to obtain resistant F1 progenies. Hybrid seeds were soaked in gibberellic acid (GA3, 1 000 ppm), Benzylaminopurine (BAP, 1 000 ppm) and hydrogen peroxide (H2O2, 1 M) solutions and water (control) for 24 hours after stratification (4 months at 5oC) and then sown in Perlite: Peat moss (1:1) potting soil. Germination was carried out in the plastic boxes with constant temperature (27oC) and relative humidity (99%). Total germination ranged from 60.39% to 78.32% in the control and GA3 treated seeds respectively. Also, GA3 significantly increased total germination when compared to the other treatments. Optimization of growth chamber, greenhouse and open field conditions for seed germination and seedling growth accelerated shoot growth up to 2 m in offsprings at the first year. © 2019, Centenary University. All rights reserved.Öğe Determination of anti-mildew activity of essential oils against downy mildew of sunflower caused by Plasmopara halstedii(Springer Heidelberg, 2020) Er, Yesim; Özer, Nuray; Katırcıoğlu, Yakup ZekaiTo evaluate the anti-mildew activity of the commercial essential oils (EOs) against pathotypes '771' and '773' of P. halstediiin mineral salt medium, the EOs obtained from different parts of Greek sage, black cumin, bay, mustard, St. John's wort, French lavender, garlic, grape, and ginger plants were examined at concentrations of 0.2%, 0.4%, 0.6%, 0.8%, and 1% on leaf discs of susceptible sunflower variety '08-TR-003'. The ginger EO had the highest anti-mildew activity at a concentration of 1% and was found to be the most effective with a decrease in sporangium quantity above 90% for pathotypes '771' and '773'. The EOs of garlic, St. John's wort, and grape followed it, respectively, with a decrease in sporangium quantity above 80%.Öğe The Effects of Seed Infestation by Fusarium proliferatum on Root and Crown Rot, Plant Growth and Phenolic Compounds in Roots of Some Pumpkin (Cucurbita pepo L.) Cultivars(2023) Sevinç, Ebru; Özer, NurayThis study investigates the reactions of four summer pumpkin cultivars (cvs. Çağlayan, Mert Bey, Sena Hanım, TG38) to root and crown rot caused by Fusarium proliferatum by taking into account criteria such as disease severity, plant growth (number of leaves, height, dry and fresh weight of shoot) and the accumulation of phenolic compounds in the roots. Seeds of each cultivar were inoculated with the pathogen and left to develop for 1 month at 25oC in a controlled climate room. The content of phenolic compounds in ethanolic root extracts was determined using high- performance liquid chromatography (HPLC). Cv. Sena Hanım had the lowest disease severity (4.40%) among the cultivars, followed by cvs. Çağlayan (10.62%) and Mert Bey (11.07%). Plants developed from inoculated seeds of cvs. Çağlayan and Sena Hanım had no decrease in the number of leaves and in length, fresh and dry weight of shoots in comparison to the control (plants from non-inoculated seeds), while cv. Mert Bey demonstrated a decrease at very low rates in shoot fresh and dry weight (2.24% and 0.77%, respectively). The phenolic compound that exhibited the highest increase in root extracts of cv. Sena Hanım compared to the control among the cultivars was p- coumaric acid (6.57-fold). This study demonstrates that p-coumaric acid can play an important role in the resistance of pumpkin to seed infestation by F. proliferatum.Öğe Effects of Seed Treatment with Trichoderma harzianum (TRIC8) on Seedling Growth and, Root and Crown Rot Disease in Wheat Caused by Fusarium culmorum(Türkiye Fitopatoloji Derneği, 2022) Özdamar, Berkcan; Özer, NurayThe effects of seed treatment with Trichoderma harzianum isolate (TRIC8) on seedling development, pre-emergence damping-off, root and crown rot caused by Fusarium culmorum in wheat were determined in this study. The all tests were carried out under controlled conditions and F. culmorum was inoculated to the sterilized soil. Seeds treated with TRIC8 were sown in inoculated soil with pathogen at different periods (at the same time as the pathogen inoculation, 3 and 5 days after inoculation). The sensitive wheat cultivar Flamura 85, a virulent F. culmorum isolate FC14 and a fungicide with active ingredient of Pyraclostrobin + Triticonazole were used through the experiments. TRIC8 had not any negative effect on seedling development when it was used alone as seed treatment. The highest increases in length, fresh and dry weight of shoots were obtained in plants developed from TRIC8 treated seeds at 3 days after inoculation. The pre-emergence damping-off was inhibited at the rate of 54.55% and 53.73% in this treatment and simultaneous treatment as the pathogen, respectively, and the rate of root and crown rot was similar to that of fungicide treated seeds. The results show that TRIC8 can be use in the soils where the pathogen was at low density.Öğe Evaluation of fungal antagonists to control black mold disease under field conditions and to induce the accumulation of antifungal compounds in onion following seed and set treatment(Elsevier Ltd, 2014) Özer, Nuray; Arın, LeventThree isolates, AS3 (non-aflotoxigenic Aspergillus flavus Link), TRIC7 and TRIC8 (Trichoderma harzianum Rifai), from onion (Allium cepa L.) growing soils were recently found to control black mold disease caused by Aspergillus niger (An) van Tieghem and to increase the accumulation of antifungal compounds in pot-grown onion sets. Their ability to increase bulb diameter and total soluble solids in marketable bulbs, to control black mold and to induce the production of antifungal compounds were tested in sets and marketable bulbs raised from treated seeds and sets, respectively, in naturally An-infested field soils at two locations. These isolates significantly controlled the disease at both locations, but they did not have any enhancing effect on set or bulb diameter and soluble solids in marketable bulbs. AS3 and TRIC8 in particular led to defense reactions with accumulation of antifungal compounds in sets and marketable bulbs in both locations. Different compounds were also identified in the fractions with highly antifungal effects. © 2014 Elsevier Ltd.Öğe Evaluation of Trichoderma harzianum to control downy mildew disease in sunflower under field conditions based on changes in the metabolite profiles of roots(Springer, 2023) Özer, Nuray; Sabudak, Temine; Kılıç, Tuğba Hilal; Evci, Göksel; Yılmaz, Mehmet İbrahimTwo years of field testing were conducted in naturally Plasmopara halstedii-infested soils to assess the effectiveness of Trichoderma harzianum isolate (TRIC8) against downy mildew (P. halstedii) on sunflower (Helianthus annuus). Seed treatment with this antagonist offered protection of 73.64% in the first year. The effects of this treatment on oil content of the seeds and metabolite profiles of roots, along with disease severity, were evaluated in the second year by comparing to the fungicide treatment (Metalaxyl M). Oil content in seeds and metabolite profile in roots were studied using Nuclear Magnetic Resonance (NMR) and gas chromatography/mass spectrometry (GC/MS), respectively. TRIC8 and fungicide treatments were found to cause significantly lower disease severity when compared to that of the control, although weather conditions were more favorable for the disease in the second year than in the first year. The oil content in seeds with TRIC8 treatment was superior to that in seeds with fungicide treatment or control. The metabolites in roots from treated plants and disease severity were subjected to principal component analysis (PCA). TRIC8 treatment increased the accumulation of some alcohols [2-ethyl-2-methyltridecan-1-ol, 2-(propylamino)ethanol], aldehydes [2,5-bis(trimethylsilyloxy)benzaldehyde, dodecanal], alkanes (dotriacontane, eicosane, heneicosane, nonacosane, nonylcyclopropane, tetracontane, tetracosane), ketones [(1-hydroxycyclohexyl)-phenylmethanone, (4-methylphenyl)-phenylmethanone], an ester (6-ethyloctan-3-yl 6-bromohexanoate) and a terpene (falcarinol), which were among the metabolites that contributed over 0.70 in PC1 and were negatively correlated with disease severity. We suggest these metabolites might be involved in defense response of sunflower against P. halstedii in the field.Öğe Farklı Ayçiçeği Genotiplerinin Perikarp ve Tohumlarında Bulunan Fungal Etmenler ile Metabolitler Arasındaki İlişkiler Üzerinde Araştırmalar(2020) Özer, Nuray; Şabudak, TemineBu çalısmada, ayçiçeginde tohum kökenli fungal patojenlerle (Alternaria alternata, A. infectoria, Bipolarıs cynodontis, Cladosporium cladosporioides, Fusarium culmorum, F. oxysporum) farklı ayçiçegi genotiplerinin (mildiyö hastalıgına karsı tolerant; TTAE 1319, 13 TR009, TTAE-13-9, 11 TR015 CL, 13 TR 00 ve hassas; 2453 A, 9728 A, 9725 A, 2517 A, 9178 A) perikarp ve tohum kısımlarından üç farklı çözücü (hekzan, metanol, kloroform) ile elde edilen ekstraktlardaki bilesikler arasındaki iliskiler incelenmistir. Tüm genotiplerin tohumları perikarba göre daha yüksek miktarda metabolit içermis, kloroform en iyi çözücü olmustur. Tolerant genotiplerin tohumlarından kloroform ile elde edilen metabolik ekstraktlar tüm fungal etmenlere karsı en az bir kriter (koloni çapı, konidi çimlenmesi ve konidi çim tüpü uzunlugunda azalma, inhibisyon zonunda artıs) yönünden yüksek antifungal etki göstermistir. Etmenlerin genotip kısımlarında bulunma oranı ile en yüksek düzeyde pozitif iliski 3?- bromocholest-5-ene (steroid) ile B. cynodontis arasında gözlenmistir. 2-Dodecyl-dodecen (alken)?in miktarının artması ile A. alternata?nın çim tüpü uzunlugunda yüksek oranda azalma oldugu, octadec-9-enoic acid (yag asidi), bombykol (alkol), benzedrex (amin), hexadecanamide (amid), dodecyl cyclohexanecarboxylate (ester)in miktarının artısı ile sırasıyla A. infectoria, B. cynodontis, C. cladosporioides, F. culmorum, F. oxysporum?un konidi çimlenmesinde yüksek oranda azalma oldugu tespit edilmistir. Tüm bu bilgiler ayçiçeginde tohum kökenli fungal etmenlerin kontrolüne ve ıslah çalısmalarına katkıda bulunacaktır.Öğe First report of brown leaf spot caused by Alternaria alternata on Aronia melanocarpa in Turkey(Springer, 2020) Polat, Zühtü; Gültekin, Mehmet Akif; Bayraktar, Harun; Özer, Nuray; Palacıoğlu, Gülsüm; Akçay, Mehmet Emin[No Abstract Available]Öğe First report of Neocosmospora solani causing stem canker on Juglans regia in Turkey(Springer, 2020) Polat, Zühtü; Gültekin, Mehmet Akif; Palacıoğlu, Gülsüm; Bayraktar, Harun; Özer, Nuray; Yılmaz, Selahattin[No Abstract Available]Öğe In vivo anti-mildew activity of essential oils against downy mildew of sunflower caused by PLASMOPARA HALSTEDII(Springer, 2021) Er, Yesim; Özer, Nuray; Katırcıoğlu, Yakup ZekaiCommercial essential oils (EO) obtained from different parts of black cumin (N. sativa), mustard (S. nigra), St. John's wort (H. perforatum), garlic (A. sativum), grape (V. vinifera), and ginger (Z. officinale) plants were evaluated for in vivo anti-mildew activity against pathotypes '771' and '773' of P.halstedii. The EOs were examined at concentrations of 0.2%, 0.4%, and 0.6% in susceptible sunflower variety '08-TR-003' as seed, foliar, and seed + foliar treatments.It was concluded that seed treatments could be applicable and appropriate, due to the phytotoxic effects of foliar treatments at increasing concentrations. Moreover, it was observed that seed treatments with St. John's wort, mustard, grape, ginger, or garlic EOs at a concentration of 0.6% exhibited anti-mildew activity with a decrease in sporangium quantity above 80% for pathotypes '771' and '773'. Seed treatment with grape EO had the highest anti-mildew activity at a concentration of 0.6% and was found to be the most effective with a decrease in sporangium quantity above 90% for both pathotypes of the pathogen.Öğe Investigations on the role of cuticular wax in resistance to powdery mildew in grapevine(Springer Japan Kk, 2017) Özer, Nuray; Şabudak, Temine; Özer, Cengiz; Gindro, Katia; Schnee, Sylvain; Solak, ErhanCuticular wax on the plant epidermis inhibits or enhances prepenetration events of powdery mildew (Erysiphe necator Schwein). We examined the role of cuticular leaf and berry waxes as a resistance mechanism in four grapevine genotypes (Italia x Mercan-174, Gurcu, Isabella, A-zer KarasA +/-) resistant to powdery mildew after natural infection and inoculation. To understand cuticular wax properties, we determined the amount of wax and antifungal effects of thin layer chromatography (TLC) fractions from cuticular leaf and berry waxes, then assessed the chemical composition of fractions with different antifungal activities using gas chromatography/mass spectrometry (GC/MS). Susceptible genotypes Cabernet Sauvignon and Italia were used for comparison. Resistant and sensitive genotypes did not differ significantly in the total amount of wax on leaves and berries; however, 27 fatty acids, 26 alkanes, 6 terpenes, 4 indole derivatives and 4 ketones, and 3 amides, 3 phenols and 3 steroids were detected in fractions with high antifungal activity (ae75% inhibition of germination) in leaf and/or berry cuticular waxes of resistant genotypes only. These compounds may be evaluated as markers for powdery mildew resistance during genotype selection in a grapevine breeding program.Öğe Marker assisted selection (MAS) for downy mildew resistance in grapevines using Rpv3.1 associated markers(Univ Agr Sci & Veterinary Med Cluj-Napoca, 2022) Akkurt, Murat; Şenses, İrem; Aktürk, Burak; Tozlu, İlhami; Özer, Nuray; Uzun, Hail IbrahimPowdery mildew and downy mildew are primary fungal diseases that cause significant damage in viticulture. Therefore, breeding powdery and/or downy mildew resistance is one of the priority subjects in grapevine breeding programs. This study aims to conduct early-selection by marker assisted selection (MAS) method among 869 genotypes obtained through crossbreeding 'Alphonse Lavallee' x 'Regent' cultivars using the markers (GF18-06 and GF18-08) associated with downy mildew resistance gene region Rpv3.1 to develop new grapevine cultivars resistant to downy mildew caused by Plasmopara viticola. A total of 869 hybrid plants which were obtained after crossing 'Alphonse Lavallee' x 'Regent' in a 3-year breeding program were used in the study. The hybrid plants were scored for the resistance level based on their sporulation intensity after artificial inoculation of P. viticola. DNA samples of the hybrid plants were amplified with GF18-06 and GF1808 markers in Polymerase Chain Reaction (PCR) for MAS. The alleles which were associated to Rpv3.1 resistance locus and the results of resistance scoring were compared, and the applicability of the markers in MAS was verified. It was determined that the GF18-08/410 bp marker can be used successfully for MAS. Gf 18-06 marker 385 bp, 390 bp and 407 bp gave false positive results in our population, respectively 8.86%, 9.02% and 37.94%. Therefore, this may limit its use for MAS.Öğe Plasmopara viticola infection process and accumulation of important stilbenes in some grapevine varieties grown in Turkey and in individuals for brined leaves(Springer Science and Business Media Deutschland GmbH, 2022) Kumaşoğlu, M.F.; Özer, Nuray; Aktürk, Burak; Uzun, Halil İbrahimThe detached leaves of three Turkish grapevine varieties (cv. Karasakız, cv. Müşküle and cv. Tekirdağ Sultani) and three hybrid individuals for brined leaves (119, 154, 200) with different resistance levels to downy mildew (Plasmopara viticola) based on sporulation area (mm2) were examined for sporangia number at 7 days, progress of the pathogen and stilbene production at different times after inoculation. A significant positive correlation was determined between number of sporangia on the lesion and sporulation area. The lowest number of stomata infected by the pathogen at 48 h after inoculation (hpi) was determined in extremely resistant 200, followed by highly resistant cv. Müşküle and 154. Vesicles of the pathogen were observed in leaves of all tested plants at 15 hpi; however, in 200 the vesicle primary hypha, which developed at 72 hpi, did not elongate into intercellular spaces of the mesophyll after that time. Elongation occurred in 119 (resistant) at 48 hpi and in cv. Müşküle and 154 at 72 hpi, but development of the pathogen was restricted to 72 hpi. Pathogen mycelia covered the intercostal fields in sensitive (cv. Karasakız) and highly sensitive (cv. Tekirdağ Sultani) varieties at 72 hpi. The amount of resveratrol was found to be high in resistant types, while the highest amount of ?-viniferin was determined in 200 at 72 hpi. Cv. Müşküle and 154 contained higher amounts of pterostilbene than 119. These new results underline the role of ?-viniferin in 200 and pterostilbene in cv. Müşküle and 154 in high resistance toward P. viticola and the importance of these grapevine types in downy mildew management. © 2021, The Author(s) under exclusive licence to Deutsche Phytomedizinische Gesellschaft.Öğe Resistance assessment of grapevine leaves to downy mildew with sporulation area scoring(Springer Science and Business Media B.V., 2021) Özer, Nuray; Uzun, Halil İbrahim; Aktürk, Burak; Özer, Cengiz; Akkurt, Murat; Aydın, SerkanThe use of resistant individuals obtained through a breeding program, aimed at decreasing chemical treatments, is one of the most promising strategies for control of downy mildew caused by Plasmopara viticola in grapevine. In this study, 869 hybrid grape individuals, obtained by crossing the resistant Regent grape cultivar with sensitive Alphonse Lavallée, were tested after artificial inoculation of detached leaves by drops of the pathogen inoculum. Sporulation severity, as visual evaluation of sporulation density including necrosis, and sporulation incidence were scored to assess resistance level, then the sporulation area (mm2) was measured for each individual. The criterium of sporulation incidence could not describe all resistance levels. Sporulation area made it possible to measure the entire area in detail for how the pathogen spread at the inoculation site. Sporulation area was not fully consistent with sporulation severity. In this context, a new scale for sporulation area was developed to determine resistance level to the pathogen by taking into account the distribution of sporulation area values within those obtained from sporulation severity scales. Six categories ranging from 0 to 0.05 mm2 (extremely resistant-ER) to ?15.1 mm2 (extremely sensitive-ES) were defined. 43 of the 869 individuals tested through the three evaluation criteria, in which no sporulation was observed, and 18 additional individuals with sporulation area of <0.05 mm2 were scored in the ER group. Microscopic analysis confirmed findings for the ER group and other resistance levels. The authors suggest that the scale of sporulation area will be useful for assessment of resistance to downy mildew on grapevine leaves. © 2021, Koninklijke Nederlandse Planteziektenkundige Vereniging.Öğe Screening for fungal antagonists to control black mold disease and to induce the accumulation of antifungal compounds in onion after seed treatment(Springer, 2011) Özer, NurayTwelve isolates belonging to the genera Aspergillus, Penicillium, and Trichoderma, from onion (Allium cepa L.)-growing soils were recently found to have antagonistic features against Aspergillus niger (An) van Tieghem, the cause of black mold disease of onion, in dual culture. In the work reported in this paper, the function of these isolates applied as seed treatment on onion seed germination was investigated. In addition, isolates with no negative effect on seeds were screened for their effect on shoot length, and for their abilities to inhibit colonization of An on seeds, to control black mold disease, to increase set bulb diameter, and to induce production of antifungal compounds in pot-grown onion sets. Application of non-aflatoxigenic A. flavus Link (AS3), T. harzianum Rifai (TRIC7) and (TRIC8) to seeds led to defense reactions with accumulation of antifungal compounds in sets, combined with increased protection against the disease, although they did not enhance bulb diameter.Öğe Susceptibility to Downy Mildew (Plasmopara Viticola) and Powdery Mildew (Erysiphe Necator) of Different Vitis Cultivars and Genotypes(Estacao Vitivinicola Nacional, 2017) Atak, Arif; Akkurt, Murat; Polat, Z.; Çelik, H.; Kahraman, K. A.; Akgül, D. S.; Eibach, R.; Özer, NurayTurkey has a very old history of viticulture and also homeland of the grapevine (Vitis spp.). Vitis cultivars belonging to different species are grown in almost every region in the country. However, particularly downy mildew and powdery mildew diseases affect the cultivars belonging to Vitis vinifera. In northern of Turkey Vitis labrusca and hybrids between V. vinifera and V. labrusca are rather common. V. labrusca cultivars or genotypes exhibit generally higher degree of resistance than V. vinifera cultivars. However, resistance level can vary from cultivar to cultivar and even from clone to clone within one cultivar. In this study, different Vitis hybrids and genotypes which exhibit different downy and powdery mildew susceptibility are compared for two years. Especially some V. labrusca hybrids and genotypes appeared resistance for both diseases. On the other hand, interspecific crosses and V. vinifera cultivars were found to be more susceptible. Using resistant lines as parent in later breeding activities, it could be possible grow high quality table cultivars with much fewer pesticide applications or possibly without them.
