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The interactions among grain-colonizing species on wheat and their effects on incidence and severity of Fusarium head blight are usually neglected in studies. Although saprophytes can predominate over pathogenic species, studies related to the control of saprophytic mycoflora in wheat production are rare. Here we hypothesized that the infection level of Fusarium and contamination level of Alternaria spp. are significantly influenced by environmental factors and their interactions and investigated the relationship between Fusarium and Alternaria spp. under field conditions and estimate its effect on conventional wheat production, The most prevalent species associated with wheat grain were Alternaria spp. (80% in 2012 and 55% in 2013), and the second was F. graminearum (9% in 2012 and 38% in 2013). In general, varieties that are moderately resistant to Fusarium infection are less contaminated with Alternaria spp. compared to susceptible and moderately susceptible varieties. F. graminearum on Alternaria spp. had a strong antagonistic effect on moderately susceptible and susceptible varieties with P

Monitoring changes in the prevalence of Fusarium species and toxin production is an important tool for the integrated control of Fusarium head blight (FHB). However, methods for the high-throughput screening of Fusarium populations have been developed using isolates with limited geographic origins. In this study, we used species- and trichothecene-specific primers to monitor the F. graminearum species complex (FGSC) originating from Serbia. We also tested the applicability of the primers to the surveillance of FHB. We analyzed two hundred and ten isolates collected from thirty two locations and five winter wheat varieties over a three-year period. Using multiple correspondence analysis (MCA), we investigated associations between Fusarium-damaged kernels (FDK) and location, variety, members of the FGSC, and their predisposition for mycotoxin production. The results revealed that the species-specific primers were not specific for 11% of the F. graminearum population. The primer sets were 98.5%, 95.2%, and 92.4% effective in the multilocus genotyping of Tri7, Tri3, and Tri5 genes, respectively. We found that individual wheat varieties were associated with isolates that could not be characterized using species- and trichothecene-specific primers. Alternaria spp. had a significant influence (p &lt, 0.001) on grain infection with F. graminearum, indicating the necessity to further investigate its impact on the pathogenesis of the F. graminearum clade.

Transcriptomics is being increasingly applied to generate new insight into the interactions between plants and their pathogens. For the wheat yellow (stripe) rust pathogen (Puccinia striiformis f. sp. tritici, Pst) RNA-based sequencing (RNA-Seq) has proved particularly valuable, overcoming the barriers associated with its obligate biotrophic nature. This includes the application of RNA-Seq approaches to study Pst and wheat gene expression dynamics over time and the Pst population composition through the use of a novel RNA-Seq based surveillance approach called “field pathogenomics”. As a dual RNA-Seq approach, the field pathogenomics technique also provides gene expression data from the host, giving new insight into host responses. However, this has created a wealth of data for interrogation. Results: Here, we used the field pathogenomics approach to generate 538 new RNA-Seq datasets from Pst-infected field wheat samples, doubling the amount of transcriptomics data available for this important pathosystem. We then analysed these datasets alongside 66 RNA-Seq datasets from four Pst infection time-courses and 420 Pst-infected plant field and laboratory samples that were publicly available. A database of gene expression values for Pst and wheat was generated for each of these 1024 RNA-Seq datasets and incorporated into the development of the rust expression browser (http://www.rust-expression.com). This enables for the first time simultaneous ‘point-and-click’ access to gene expression profiles for Pst and its wheat host and represents the largest database of processed RNA-Seq datasets available for any of the three Puccinia wheat rust pathogens. We also demonstrated the utility of the browser through investigation of expression of putative Pst virulence genes over time and examined the host plants response to Pst infection. Conclusions: The rust expression browser offers immense value to the wider community, facilitating data sharing and transparency and the underlying database can be continually expanded as more datasets become publicly available. EEA Bordenave Fil: Adams, Thomas M.. John Innes Centre. Norwich Research Park; Reino Unido Fil: Olsson, Tjelvar S.G. John Innes Centre. Norwich Research Park; Reino Unido Fil: Ramírez-González, Ricardo H. John Innes Centre. Norwich Research Park; Reino Unido Fil: Bryant, Ruth. RAGT Seeds Ltd.; Reino Unido Fil: Bryson, Rosie. BASF SE. Agricultural Centre; Alemania Fil: Campos, Pablo Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; Argentina Fil: Fenwick, Paul. Limagrain UK Ltd.; Reino Unido Fil: Feuerhelm, David. Syngenta Seeds Ltd.; Reino Unido Fil: Hayes, Charlotte. Elsoms Wheat Ltd.; Reino Unido Fil: Henriksson, Tina. Lantmännen Lantbruk; Suecia Fil: Hubbard, Amelia. NIAB; Reino Unido Fil: Jevtić, Radivoje. Institute of Field and Vegetable Crops; Serbia Fil: Judge, Christopher. NIAB; Reino Unido Fil: Kerton, Matthew. DSV United Kingdom Ltd.; Reino Unido Fil: Lage, Jacob. KWS UK Limited; Reino Unido Fil: Lewis, Clare M. John Innes Centre. Norwich Research Park; Reino Unido Fil: Lilly, Christine. Frontier Agriculture; Reino Unido Fil: Meidan, Udi. Hazera Seeds Ltd.; Israel Fil: Novoselović, Dario. Agricultural Institute Osijek; Croacia Fil: Patrick, Colin. Masstock Arable (UK) Ltd.; Reino Unido Fil: Wanyera, Ruth. Kenya Agricultural and Livestock Research Organization; Kenia Fil: Saunders, Diane G.O. John Innes Centre. Norwich Research Park; Reino Unido

To date, studies have usually focused on the impact of abiotic factors on the distribution of plant pathogens and have built forecast models for the prediction of pathogen outbreaks. However, the impact of the combined effects of biotic and abiotic factors on the prevalence of economically important pathogens has usually been neglected. The objective of this study was to determine the relationship between powdery mildew and rusts of wheat and to examine how the combined effects of abiotic and biotic factors influence their prevalence. The study was conducted in the period 2016–2019 using the collection of 2158 genotypes of winter wheat. The most influential factors on disease indices and relationships among obligate pathogens were determined using multiple regression models and principal component analysis. The possibility of the coexistence of different rust species in the same growing season and in the same field was shown. The significant influence of fluctuations in winter temperatures on changes in the prevalence of obligate pathogens was determined. The strong impact of genotypes and their reaction on climatic elements in certain phenological stages were shown to be significant factors influencing the interactions among obligate pathogens and the predominance of one pathogen over another.

Thousand kernel weight (TKW) is a yield component associated with grain quality. It is reported in the literature that TKW is significantly influenced by varieties, agro-ecological conditions and disease indices, but the influence of their interactions on TKW loss has rarely been taken into consideration. The main objective of this study was to examine the combined effects of multiple diseases and climatic conditions on TKW losses in winter wheat. Leaf rust, powdery mildew, and Septoria tritici blotch were considered biotic predictor variables in regression models explaining TKW losses. Monthly averages of temperature, relative humidity and total rainfall in May and June in the 2006-2013 growing seasons were used as abiotic predictor variables. The results of this study indicated a significant low positive correlation between yield loss and TKW loss in the two varieties. TKW losses were less influenced by leaf rust, powdery mildew, and Septoria tritici blotch than yield losses. The significant influence of the interaction between variety and the environmental conditions on TKW loss was confirmed from the general linear model function. The results of this study indicated that factors influencing yield and yield component losses are part of the complex environment, and the relationship between them should be investigated with respect to their interactions.

The purpose of this study was to determine the influence of soil properties on the biodiversity of soil fungi. An analysis of the fungal diversity of eight different soil types with different soil texture, organic matter, carbonate content, pH, cation exchange capacity and different land uses identified a total of 38 different species grouped in 24 genera. Among all soil fungi identified, the most common were organic matter decomposers. The species most frequently identified were Aspergillus spp., Alternaria sp., Fusarium spp., Mortierella sp. and Penicillium spp. The greatest similarities between fungal communities were seen in arable land with a low or moderate cation exchange capacity and organic matter content, while the least similarities were found between forest Cambisol (CM) and garden soils. The Shannon-Wiener diversity index indicated the highest diversity in Chernozem (CH), Fluvisol (FL) and Arenosol (AR) all used as arable land or garden soil, while the lowest diversity was recorded in a Gleysol (GL) under a meadow, caused by poor aeration and a poor water regime. Canonical correlation analysis (CCA) showed the relationship of soil fungi with all soil environmental factors analysed and indicated that certain soil fungi were positively related to organic matter, sand and clay content.

Data related to genetic diversity of F. graminearum chemotypes in Serbia are limited, thus the main objective of this study was to analyze the divergence of genes associated with the trichothecene cluster. F. graminearum was shown to be the dominant Fusarium species in Serbia occurring with frequency of 65.6% in 2016/2017 growing season. Isolates of F. graminearum dominantly belonged to SCAR type 1 (104/105) producing PCR product of 420 bp, but one isolate was proven to be SCAR type 6 producing PCR product of 400 bp. This is the first report of the presence of SCAR type 6 in Southeastern Europe. Results from this study reveal that F. graminearum populations were shown to be DON-DON chemotype with respect to Tri7 and Tri13 genes. All but one of these isolates were 15-AcDON chemotypes based on Tri3 gene. One isolate carried a deletion of Tri7 and was found to be 3-AcDON by using Tri303F/R primer pair. This is the first record on the presence of a 3-AcDON isolate with the Tri7 deletion in Serbia. The Tri7F/Tri7DON primer pair was not effective if isolates carried more than four 11-bp repeats in the Tri7 gene. Primer pair GzTri7f1/r1 was proven to be more effective in comparison with Tri7F/Tri7DON. Genetic variation ranged from 57 to 80% with no significant association of Tri7 alleles with localities. Results of this study have brought new insights into the distribution and population structure of F. graminearum in Serbia.

Investigations related with factors influencing root and crown rot are rare and mainly related to farming practice and soil management. The main objective of this study was to examine broader range of factors influencing stem-base infestation of winter wheat in the field conditions. The effect of spatial distribution of infected plants on disease index (DIs) assessments was also investigated. Analysis of factors influencing DIs of crown rot of wheat demonstrated significant influence of the growing seasons (P lt 0.001) and extreme fluctuations in winter temperatures (P lt 0.001). In addition to that, localities together with their interaction with the growing season also significantly influenced DIs (P lt 0.001). Aggregation of infected plants influenced variability of DI estimations, and it was pointed out that more extensive investigation should be conducted on broad range of DI in order to establish sampling method giving uniform sampling precision. Fusarium graminearum was shown to be predominant Fusarium species in Serbia (72.6%) using sequence-characterized amplified region analysis. Interestingly F. oxysporum was isolated in higher frequencies (27.4%) than it was reported in the literature. Given that there were no reports on the diversity of Fusarium species causing crown rot of wheat in Serbia, this study presents first report on this important subject. It also indicated that more attention should be focused on combined effects of abiotic and biotic factors influencing stem-base infestation of winter wheat. This knowledge will contribute to better understanding of factors influencing root and crown rot of wheat which would ensure sustainable disease management in the future.

International audience; The areas under the field pea are constantly increasing in Bosnia and Herzegovina. However, pea is susceptible to a large number of diseases, especially to Ascochyta blight, which is considered as one of the most economically important diseases of legume crops throughout the world (Le May et al. 2014; Rubiales et al. 2018). In May 2016, characteristic Ascochyta blight symptoms were observed on stems and flowers of field pea plants (Pisum sativum L.) grown at Velika Ilova (northern Bosnia and Herzegovina).

Reports on the effectiveness of Fusarium head blight (FHB) control measures do not follow the same pattern in different regions, and the combined effects of abiotic and biotic factors on FHB are not fully understood. Consequently, the main objective of this study was to examine divergence in susceptibility reactions of winter wheat genotypes to FHB when exposed to the combined effects of cultivation practices, cultivar properties, year and the presence of interacting Fusarium spp. as an inherent whole. Analysed data originated from 633 grain samples collected from 434 localities in an eight-year period as a part of investigations related to the development of the DONcast® Europe prediction model. This study suggests that ploughing could increase the risk of the occurrence of less frequent toxigenic Fusarium species. Stubble management generated more divergent environmental factors than no-till farming, influencing greater variability in the relationship between deoxynivalenol (DON) accumulation and grain infection. The results of this study indicated differences in susceptibility reactions of varieties to FHB and suggested that more attention should be focused on the specificity of the interaction between variety and combined environmental stressors to ensure more predictive and sustainable wheat production.

Yield losses in field crops are most commonly predicted by using regression models that include either biotic or abiotic factors as predictor variables. Knowing that yield loss is a complex trait, the potential capability of regression models for predicting yield losses by using models containing both biotic and abiotic factors as predictors were estimated in this study. Biotic factors considered in regression models were: leaf rust, powdery mildew, septoria tritici blotch and tan spot occurrence on the varieties Barbee and Durumko known to have various degrees of susceptibility to obligate parasites and leaf blotch diseases. Among abiotic factors, monthly averages of temperature, relative humidity and total rainfall taken from November to June for growing seasons 2006–2013 were used as predictors. In 2014, yellow rust became the predominant pathogen over leaf rust, thus 2014 and 2015 were excluded from regression models and analyzed separately. Since a high correlation was found between abiotic and biotic factors, partial least squares regression, stepwise regression and best subsets regression were applied. Best subsets regression revealed that models consisted of both biotic and abiotic factors were more precise in estimating regression coefficients and predicting future responses. The potential yield loss predictions, conducted using these models, were regressed with actual yield losses, and high coefficients of determination (R 2 = 79% for Barbee; and R 2 = 63% for Durumko) were obtained. It was also evident that using more predictors in regression models does not necessarily mean that the model would have a higher potential in making yield loss predictions. This study confirms that the relationship between a disease scoring scale and yield loss is not straightforward and higher potentials for yield loss predictions were given due to the regression models using abiotic and biotic predictor variables.

One of the most important tasks in wheat breeding program is development of high yielding wheat cultivars by crossing the lines with good general combining ability (GCA) and selecting desirable genotypes within its segregating population for grain yield traits. The objective of this study was to estimate the combining ability and gene action involved in the expression of the traits grain weight per spike and grain weight per plant of wheat in F1 generations, in 5 × 5 half diallel cross of bread wheat varieties (Triticum aestivum L.). The results of applying combining ability analysis indicated that among the parents, genotypes Sara, Pobeda and Renesansa were found to be the best general combiners for the both investigated traits. The best specific crosses for both traits were Sara/Partizanka, Pobeda/Sara, Renesansa/Partizanka, Partizanka/Pesma and Pobeda/Pesma. Most of the specific crosses involved high × high, high × low and low × low general combiners. The results of regression analysis, as well as the analyses of components of genetic variation indicated over-dominance in the inheritance of examined traits suggested that selection in later segregating generations may lead to fairly good improvement in these characters, One of the most important tasks in a wheat breeding program is the development of high yielding wheatcultivars by crossing the parents with good general combining ability (GCA) and selecting desirable genotypeswithin its segregating generations for grain yield traits. The objective of this study was to estimate thecombining ability and gene action involved in the expression of the traits grain weight per spike and grainweight per plant of wheat in F1 generations, in 5 × 5 half diallel cross of bread wheat varieties (Triticumaestivum L.). The results of applying combining ability analysis indicated that among the parents, genotypesSara, Pobeda and Renesansa were found to be the best general combiners for the both investigated traits. Thebest specific crosses for both traits were Sara/Partizanka, Pobeda/Sara, Renesansa/Partizanka,Partizanka/Pesma and Pobeda/Pesma. Most of the specific crosses involved high × high, high × low and low ×low general combiners. The results of regression analysis, as well as the analyses of components of geneticvariation indicated over-dominance in the inheritance of examined traits suggested that selection in latersegregating generations may lead to fairly good improvement in these characters.

A field experiment was conducted at the experimental field of the Institute of Field and Vegetable Crops in Novi Sad to investigate the effect of forage winter pea and winter oat intercropping on ascochyta blight and powdery mildew infections. Seeding rations of pea and oat in Treatment 1 (50:50%) and Treatment 2 (75:25%, respectively) reduced ascochyta leaf infection by 32.5% and 12.8%, and powdery mildew infection by 12.3% and 17.5%, respectively, compared to pea monoculture used as a control (Treatment 3). The same seeding rations in Treatment 1 and 2 reduced ascochyta blight on pea plants by 37.2% and 18.3%, respectively. However, there were no significant differences between the treatments in reducing powdery mildew on plants. The effects of different treatments on the average number of pods per plant, seed per pod, shriveled pods and seed weight were analyzed using Spearman's correlation coefficient. Negative but not statistically significant effects on those measured parameters were registered in Treatments 2 and 3, while Treatment 1 showed positive effects on all parameters except shriveled pods. According to all data obtained in this research, the intercropping mixture of pea and oat at 50:50% seeding ratio had the best effect on the measured parameters while the intercropping mixture of pea and oat at 75:25% seeding ratio had low to moderate effect in comparison with pea monocrop. Poljski ogled je postavljen na oglednom polju Instituta za ratarstvo i povrtarstvo u Novom Sadu kako bi se istražio uticaj smeše ozimog stočnog graška i ozimog ovsa na pojavu antraknoze i pepelnice. Smeše graška i ovsa u Tretmanu 1 (50:50%) i Tretmanu 2 (75:25%) smanjile su antraknozu lista za 32.5% i 12.8%, a pepelnicu za 12.3% i 17.5% u odnosu na monokulturu graška, koja je uzeta za kontrolu (Tretman 3). Navedene smeše u Tretmanima 1 i 2 su smanjile pojavu antraknoze celih biljaka za 37.2% i 18.3%. Međutim, između tretmana nije uočena značajnija razlika u pojavi pepelnice na celoj biljci graška. Uticaj tretmana na prosečan broj mahuna po biljci, šturih mahuna po biljci, zrna po mahuni i mase semena analizirani su Spearman-ovim koeficijentom korelacije. Negativne ali ne statistički značajne korelacije sa merenim parametrima su registrovane u Tretmanima 2 i 3, dok je Tretman 1 imao pozitivan efekat na merene parametre sa izuzetkom šturih mahuna. Prema dobijenim rezultatima u sprovedenom istraživanju, združena setva ozimog stočnog graška i ozimog ovsa u smeši 50:50% je imala najbolji efekat na istraživane parametre dok je združeni usev graška i ovsa u smeši 75:25% imao slab do srednji uticaj u poređenju sa kontrolom, odnosno monokulturom graška.

Trichoderma species have been registered as species with important plant growth promoting potential and antagonistic effect against various phytopathogens. Trichoderma isolates originating from different soil types from the Vojvodina region (Serbia) were screened using dual culture test for their antagonistic effect against the pathogen Sclerotinia sclerotiorum. All tested isolates had high radial growth inhibition (RGI) factors of the pathogen and high colonization percentage. Growth promoting activity of Trichoderma isolates on soybean seeds was tested under glasshouse conditions. Soybean seeds were coated with suspensions of different Trichoderma isolates and seed germination percentage, root and shoot length were measured. According to data analysed in Statistica 10, using Duncan's test, there were no significant effects on shoot length among the tested isolates, compared to the control. The four tested Trichoderma isolates showed significant positive effects on germination, root length and vigour index, while two isolates exhibited no significant effect on any of the measured parameters. Vrste roda Trichoderma su poznate po svom antagonističkom efektu na veliki broj fitopatogenih organizama kao i po stimulativnom efektu za rast biljke. Izolati Trichoderma spp. testirani u ovom istraživanju su izolovani iz različitih tipova zemljišta u Vojvodini (Srbija). Test dvojnih kultura je korišćen za testiranje antagonističkog dejstva izolata na patogena Sclerotinia sclerotiorum. Svi testirani izolati su imali visok RGI (faktor inhibicije porasta micelije patogena) i visok procenat kolonizacije patogena. Stimulativni efekat rasta Trichoderma izolata na seme soje je testiran u uslovima staklenika, i sedmog dana su mereni dužina korena, izdanka i klijavost semena tretiranih suspenzijom različitih izolata Trichoderma spp. Svi podaci su analizirani primenom Duncan testa u programu Statistica 10, i ukazuju da nije bilo statistički značajne razlike u dužini izdanaka tretiranih semena i kontrole. Četiri izolata su statistički značajno uticala na povećanje dužine korena, klijavosti i vigor indeksa u odnosu na kontrolu, dok dva izolata nisu statistički značajno uticala ni na jedan od merenih parametara.