Research on nematodes on onion in Karaman in Turkey

A study was estabilished for investigation of nematodes in onion growing areas in Karaman province in Turkey by support of the Turkish Scientific and Technical Research Foundation in 2011 for three years. The first step of the study was to investigate the distribution of the nematodes in onion growing areas in Karaman province where has an important role in onion production in Turkey. Ditylenchus spp. (Filipjev 1936) (Tylenchida: Anguinidae) were in 15% of plants and 61% of soils. Other widespread plant parasitic genera were Paratylenchus (Micoletzky 1922) (Tylenchida: Paratylenchidae) (56%) and Tylenchus (Bastian 1865) (Tylenchida: Tylenchidae) (49%). Besides fungivorous and bacterivorous nematode genera were also abundantly found. Second objective of the study was to estabilish the yield loss by stem and bulb nematode found in a farmer field. Study was inferred up to 40% yield loss duo to the stem and bulb nematode. The most suitable and less labored method to keep the nematode populations under damage level is use of the resistant cultivars. Resistance reaction of commercially produced onion cultivars and breeding material in Turkey was investigated under controlled conditions. The cultivars of Imrali Kirmasi, Karaca, Banka, Mor Sogan Tohumu, Aki and Kirşehir local population (Gen Bank No: TR69450) were found hope giving for resistance against D. dipsaci

Resistance of Iranian landrace wheat to the cereal cyst nematode, Heterodera filipjevi

The cereal cyst nematode (CCN), Heterodera filipjevi,has a global distribution and can reduce wheat yields by up to 32 %. Plant genetic resistance can effectively manage H. filipjevi populations, so 31 Iranian wheat landrace accessions were screened for H. filipjevi resistance under greenhouse conditions. PI628144 (syn. AUS28321) was resistant and five other accessions moderately resistant to H. filipjevi and may provide novel CCN-resistance for plant breeders to exploit. © 2016, Australasian Plant Pathology Society Inc

Molecular characterization of Ditylenchus dipsaci on garlic in Turkey

Garlic plant, which has an important place in the world economy as well as in human nutrition, is grown extensively in Turkey. The stem and bulb nematode, Ditylenchus dipsaci (Kühn) is one of the most important biotic stresses and is under quarantine as it significantly interrupts garlic production wherever it emerges. Thus, being up to date regarding the distribution and population of the stem and bulb nematode, which is locally found in garlic cultivation areas, identification of the races found on the garlic plant at the molecular level and knowing the host spectrum of the races found at the region are of great importance. The objective of this study is to perform species diagnosis using the species-specific molecular markers at ITS-rDNA regions of the stem and bulb nematode isolates collected from the garlic cultivation areas in Turkey in 2016 and 2017. In the study, molecular screening data of the nematodes isolated from the plant and soil samples were analyzed phylogenetically. In this study, upon molecular screening using 9 different species-specific SSR and SCAR primers, it was found that 34 nematode samples of 53 are D. dipsaci. Nematode samples were from the garlic fields in Kastamonu, Amasya, Aksaray, Tekirdağ, Tokat, Balıkesir, Bursa, Hatay, Gaziantep, Kahramanmaraş, Adıyaman, and Kırklareli provinces. Identification of stem and bulb nematodes found in the areas of garlic cultivation with this study will be useful for conscious and efficient control applications to this nematode. © 2019, Deutsche Phytomedizinische Gesellschaft.215O468This research was funded by Turkish Scientific and Technical Research Council (TUBITAK) (Project No.: 215O468). Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations

Screening for resistance to Heterodera filipjevi (Madzhidov) Stelter (Tylenchida: Heteroderidae) and Pratylenchus thornei (Sher &allen) (Tylenchida: Pratylenchidae) sister lines of spring wheat

Breeding for resistance to the cereal cyst nematodes (CCN) Heterodera filipjevi (Madzhidov,) Stelter, and H. avenae (Wollenweber) and to the root lesion nematode (RLN) Pratylenchus thornei (Sher &Allen) is presently being undertaken by breeding programs at research institutions in Turkey. This study was carried out to screen for nematode resistance in an advanced spring bread wheat breeding population, 42 lines (F9) developed at CIMMYT in Mexico, by crossing resistant parent the Middle-Eastern landrace AUS4930 7.2 and susceptible parent, the widely adapted, high yielding CIMMYT line, Pastor. The results demonstrate that 31 lines are resistant to P. thornei and 5 lines are resistant to H. filipjevi. Only 4 of these lines (2, 7, 23 and 41) are resistant to both nematodes. Lines 2, 7 and 41 also contain the known resistance gene, Cre1. Although some lines carry the Cre1 gene, they are susceptible to either both or one of these nematodes. There is no association among H. filipjevi, P. thornei and Cre1 resistance due to differences in the resistance region in the plant genome

Occurrence and abundance of nematodes on onion in Turkey and their relationship with soil physicochemical properties

The distribution of plant-feeding and free-living nematodes in large scale onion production areas in five geographical regions in Turkey was investigated in 2016 and 2017. Ditylenchus spp. and Tylenchus spp. were widely distributed. The stem and bulb nematode, Ditylenchus dipsaci, was found in 48 locations from 13 provinces. Other plant-feeding nematode genera were Pratylenchus, Paratylenchus and Pratylenchoides. Pratylenchus thornei was the most widely distributed root-lesion nematode species in onion fields in 11 locations from seven provinces. Pratylenchus neglectus was present in three locations and P. vulnus was in four locations. Aphelenchus spp. and Aphelenchoides spp. were the principal fungal-feeding nematodes in onion-growing areas. The most abundant bacterial-feeding nematode genera were Acrobeloides, Cephalobus, Eucephalobus and Rhabditis. Acrobeles and Wilsonema genera were low in occurrence and abundance. Nematodes from Dorylaimida and predator nematodes, Mononchus spp., were also found. The numbers of Ditylenchus from plant samples were significantly correlated positively to silt content, and significantly correlated negatively to organic matter and calcium content. © 2019 Copyright 2019 by Koninklijke Brill NV, Leiden, The Netherlands.215O468This research has been financially supported by Turkish Scientific and Technical Research Council (TUBITAK) (Project no: 215O468)

Distribution, frequency and occurrence of cereal nematodes on the Central Anatolian Plateau in Turkey and their relationship with soil physicochemical properties

The distribution of important plant-parasitic and free-living nematodes in the cereal production areas of the Central Anatolian Plateau (CAP) of Turkey was investigated with systematic surveys. Two important plant-parasitic nematode groups were found widely distributed; cereal-cyst nematodes (78.3%) and root-lesion nematodes (42.6%). Cereal cyst nematodes (CCN) were identified as Heterodera filipjevi in 18 provinces. Heterodera latipons was found in only one province. Pratylenchus thornei and P. neglectus were the most widely distributed species of root-lesion nematodes. Other frequently recorded plant-parasitic nematodes belonged to the genera Geocenamus (52.4%), Pratylenchoides (35.6%), Helicotylenchus (29.7%) and Paratylenchus (19.2%). Konya on the southern CAP had a significantly high incidence of P. neglectus as well as free-living nematodes. The incidence of CCN was greatest in areas of sandy soils on the CAP, with densities of up to 95 cysts (100 g soil)-1. Population densities of Geocenamus, Pratylenchus and Pratylenchoides were high in some locations. Soil physicochemical properties were investigated for their relationship to nematode distribution. There was a slight positive correlation of P. thornei and clay content; conversely, there was a significant negative correlation of P. neglectus with clay and a positive correlation with sand. Electrical conductivity (EC) was positively correlated with P. neglectus. Nematodes in the genera Helicotylenchus, Paratylenchus, Trophurus and Tylenchorhynchus were only recorded at low population densities in the sampled area. By contrast, nematodes in the genera Aphelenchus, Aphelenchoides, Ditylenchus, Dorylaimus, Tylenchus and bacterivorous genera had relatively high populations. Total free-living nematodes were positively correlated with EC and zinc (Zn) concentration. The Zn content of soil was generally at a level deficient for plant growth. Copyright © Koninklijke Brill NV, Leiden, 2012

The importance and management strategies of cereal cyst nematodes, Heterodera spp., in Turkey

Cereal cyst nematodes (CCNs) can cause significant economic yield losses alone or in combination with other biotic and abiotic factors. The damage caused by these nematodes can be enormous when they occur in a disease complex, particularly in areas subject to water stress. Of the 12 valid CCN species, Heterodera avenae, H. filipjevi, and H. latipons are considered the most economically important in different parts of the world. This paper reviews current approaches to managing CCNs via genetic resistance, biological agents, cultural practices, and chemical strategies. Recent research within the soil borne pathogen program of the International Maize and Wheat Improvement Center has focused on germplasm screening, the potential of this germplasm as sources of resistance, and how to incorporate new sources of resistance into breeding programs. Breeding for resistance is particularly complicated and difficult when different species and pathotypes coexist in nature. A lack of expertise and recognition of CCNs as a factor limiting wheat production potential, combined with inappropriate breeding strategies and slow screening processes limit genetic gains for resistance to CCNs. © 2014, Springer Science+Business Media Dordrecht