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The cereal cyst nematode (Heterodera latipons) is becoming an economically important species in global cereal production as it is being identified in many new cereal cultivated areas and causes significant losses. Consequently, understanding its biology becomes crucial for researchers in identifying its vulnerabilities and implementing effective control measures. In the current study, different morphological and biochemical changes of H. latipons cysts containing eggs with infective juveniles from a barley field in Jordan were studied during the summer of 2021, at two sample dates. The first, at the harvest of the cereal crop (June 2021), when the infective second-stage juveniles (J2s) were initiating diapause, and the second, before planting the sequent cereal crop (late October 2021), when the J2s were ending diapause. The studied population was characterized morphologically and molecularly, showing 98.4% molecular similarity to both JOD from Jordan and Syrian "300" isolates of H. latipons. The obtained results and observations revealed that there were dramatic changes in all the investigated features of the cysts and eggs they contained. Morphological changes such as cyst color, sub-crystalline layer, and thickness of the rigid eggshell wall were observed. A slight change in the emergence time of J2s from cysts was observed without any difference in the number of emerged J2s. The results of biochemical changes showed that the total contents of carbohydrates, glycogen, trehalose, glycerol, and protein were higher in cysts collected in October when compared to those cysts collected in June. The SDS-PAGE pattern indicated the presence of a protein with the size of ca. 100 kDa in both sampling dates, whereas another protein (ca. 20 kDa) was present only in the cysts of October. Furthermore, the expression of trehalase (tre) gene was detected only in H. latipons collected in October. The outcomes of this study provide new helpful information that elucidates diapause in H. latipons and may be used for the implementation of new management strategies of cyst nematodes. [ABSTRACT FROM AUTHOR]

Heterodera schachtii (Schmidt, 1871) (Nematoda: Heteroderidae) is one of the most widespread plant-parasitic nematodes (PPNs) associated with cabbages, which cause severe yield losses in cruciferous vegetables. This study aimed to improve the current understanding of the prevalence and detection of H. schachtii in the cabbage-growing areas of Niğde Province, Türkiye. Field surveys were conducted between November and December 2021, and 100 soil samples were collected immediately after cabbage harvesting. Heterodera schachtii populations were identified by morphological and morphometric methods along with Internal Transcribed Spacer of the ribosomal region (ITS-rDNA) and Cytochrome Oxidase Subunit (COI-mtDNA) sequencing. The mean body length of H. schachtii was 463 ± 7 μm, while stylet and hyaline length ranged between 20.7–27.8 μm and 20.1–32.1 μm, respectively. Nearly half of the surveyed areas were infested with H. schachtii with a 41% incidence rate. However, the Merkez District had the highest proportion of infested fields with an over 51% incidence rate. The population density was determined in 41 samples with a mean of 79.5 cysts per 250 g of soil. These results will help to determine the control and management strategies of H. schachtii. [ABSTRACT FROM AUTHOR]

The effects of the seed gall nematode 'Anguina tritici' (Steinbuch, 1799) on the agronomic characteristics of some bread wheat cultivars were investigated at the Trakya Agricultural Research Institute, Türkiye. An experiment was carried out in two different locations in Edirne in the 2019–2020 growing season. A total of 19 winter bread wheat cultivars were evaluated to assess infected grain number, healthy grain number, infected grain rate and yield. According to the results of the combined variance analysis, a statistically significant difference (p ≤.01) was found in terms of yield from the application of inoculum. Compared to the control in wheat cultivars, there was a 52.15% decrease in the yield of infected parcels due to the damage of wheat seed gall nematode. The highest yield loss in infected parcels occurred in cv. Damla with 64.22% loss, while the least yield loss occurred in cv. Yüksel cultivar with 19%. Pathological symptoms, curling and twisting of the leaves, were not observed on green plants of cv. Yüksel cultivated in the field. [ABSTRACT FROM AUTHOR]

Nematodes attack cereal crops resulting in significant yield losses, estimated at 10%. The plant parasitic nematodes of the genus Heterodera attack cereals, particularly wheat, causing costly financial losses due to impact on yield. The soil borne pathogens program at the International Maize and Wheat Improvement Center (CIMMYT) in Turkey has focused on screening wheat germplasm to identify sources of Heterodera resistant varieties for almost 20 years. The aim of this current study was to validate the finding that resistant lines demonstrate resistant reactions under controlled conditions and to test whether they present tolerant reactions when challenged with cyst nematodes under two different locations in field conditions. The results of this study, including the check lines, indicated that 27 and 28 lines maintained their reactions to H. filipjevi in Eskisehir and Yozgat field, respectively, and 23 lines were the same in both locations. In terms of tolerance, 3 and 13 lines proven to be tolerant and moderately tolerant to H. filipjevi in Yozgat field. In Eskisehir field, 13 and 14 lines were tolerant and moderately tolerant. In both locations, L7 showed tolerance reaction, although it was susceptible. The majority of the resistant germplasm (60%, 14 lines) of screened lines from the Turkey CIMMYT–ICARDA (TCI) nursery were found to be resistant to both H. filipjevi populations including L1, L3, L6, L15, L21, L26, and L34, whereas 17% (four lines) from the USA had the same reaction. L32 showed a high level of resistance and tolerance in both locations and could prove to be promising lines in the breeding programs. The International Winter Wheat Improvement Program (IWWIP) formerly used these resistant lines in the crossing block and subsequently distributed them to more than 150 international collaborators. Regression analysis revealed a negative correlation between yield and RF of H. filipjevi in both nematode populations, which describes the negative impact of this pest on winter wheat. The results of this study are very important for breeding programs especially for the IWWIP, a joint program between the Turkish Ministry of Agriculture and Forestry, CIMMYT, and the International Centre for Agricultural Research in the Dry Areas (ICARDA).

Morphological and molecular diversity among 11 populations of cereal cyst nematodes from different wheat production areas in Morocco was investigated using light microscopy, species-specific primers, complemented by the ITS-rDNA sequences. Morphometrics of cysts and second-stage juveniles (J2s) were generally within the expected ranges for Heterodera avenae; only the isolate from Aïn Jmaa showed morphometrics conforming to those of H. latipons. When using species-specific primers for H. avenae and H. latipons, the specific bands of 109 bp and 204 bp, respectively, confirmed the morphological identification. In addition, the internal transcribed spacer (ITS) regions were sequenced to study the diversity of the 11 populations. These sequences were compared with those of Heterodera species available in the GenBank database (www.ncbi.nlm.nih.gov) and confirmed again the identity of the species. Ten sequences of the ITS-rDNA were similar (99–100%) to the sequences of H. avenae published in GenBank and three sequences, corresponding with one population, were similar (97–99%) to H. latipons.

Summary: Plant-parasitic nematodes are among the most influential soil organisms worldwide and have a detrimental impact on wheat productivity; they also play a major role in maintaining soil diversity. However, limited information is available on the biodiversity of nematodes associated with wheat cropping systems in Turkey. To address this knowledge gap, 45 wheat fields in the Afyonkarahisar Province of Turkey were sampled in 2021 in order to extract and identify nematodes. A total of 14 genera and 44 species of these nematodes were identified based on their physical traits and ITS DNA sequences examination. Shannon diversity index was used to determine the prevalence and biodiversity features of these nematodes. This study represents the first comprehensive research on plant-parasitic nematodes from wheat-growing regions in the Afyonkarahisar Province. The genera Helicotylenchus , Heterodera , Merlinius , Pratylenchoides and Pratylenchus dominated with a high relative abundance percentage >60%, and were extremely common (>90% for each). The average Shannon index of nematode species in the wheat fields was 2.20, with an evenness value of 0.81, indicating moderate diversification and good nematode evenness. This study also revealed a significant correlation between nematode genus biodiversity and edaphic, climatic and geographical factors. Finally, this research demonstrated a remarkable diversity of soil nematodes associated with wheat crops and they have the potential to be useful tools for extensive soil bio-study. [ABSTRACT FROM AUTHOR]