Black Point Disease Research Articles

Assessment of avoidable yield losses due to insect pests and diseases in wheat (Triticum aestivum)

Biotic stress, including insect pests and diseases, poses a significant constraint to the cultivation of food grain crops including wheat (Triticum aestivum L.) which is affected by several pests. Therefore, the present study was carried out during winter (rabi) seasons of 2020–21 and 2021–22 at the research farm of ICAR-Indian Agricultural Research Institute, New Delhi to assess the yield loss due to multiple pests in a holistic manner with wheat variety HD 3086 (Pusa Gautami). Estimated avoidable yield loss due to higher aphid infestation and minimum disease incidences of Karnal bunt and black point disease during both the seasons (2020–21 and 2021–22) was 7.79% and 6.10%, respectively. Meanwhile, in treatment with a lower aphid infestation and minimum disease incidence of Karnal bunt and black point diseases, yield losses were 4.80% and 6.90% in 2020–21 and 2021–22, respectively. Incidences of the diseases were found to be minimal in both the seasons, thus the estimated avoidable losses attributed to aphids to a large extent.

Incidence of Black Point on Wheat Seeds in Different Location of Uttarakhand, India

An experiment was conducted to determine the incidence of black point disease in wheat varieties with different locations caused by A. alternata fungal pathogens of wheat grain. Fresh seeds of popularly cultivated wheat varieties, preferably viz., GW 366, GW 496, Lok 1, and GW 1, were collected after harvesting season from the farmers’ fields of wheat growing areas of middle Uttarakhand viz., Sahaspur, Roorkee, Haridwar, and Dehradun. At least 50 samples were collected from each of the districts. Five primary samples were collected and mixed from the harvested seed lot to have composite samples. Working samples were prepared from composite samples by repeated halving method. The black point disease incidence might be due to the inherent boldness of the seeds. Florets remain more open in bold-seeded varieties, enhancing the chances of more seed infection during seed development. Moreover, low night temperatures during the flowering period, severe dew at the seed maturation stage, frequent and heavy crop irrigation, and excessive application of nitrogenous fertilizers may lead to a higher incidence of the black point disease. Besides, infected seeds reveal seed rot, necrosis, and shriveling. High humidity due to prolonged rainfall or heavy dew deposition during seed maturation favors the black point. As our research findings varied, GW366 is significantly the highest incidence of black point disease.

Occurrence of Karnal bunt and black point disease of wheat in northern part of Haryana

Karnal bunt and black point are major issues in Haryana's seed production programmes, reducing the quality of wheat seed. During the rabi season of 2021-22, a survey was conducted to determine the status of Karnal bunt and black point in major wheat growing regions covering 11 districts of northern Haryana, viz., Hisar, Yamunanagar, Sirsa, Fatehabad, Ambala, Jind, Kurukshetra, Kaithal, Karnal, Panipat, and Sonipat. A total of 849 wheat grain/seed samples were collected from 49 grain markets and seed producers as part of the survey. The results revealed that range of Karnal bunt and black point infection was between 0.05–0.40 and 0.05-2.25 per cent respectively in these districts which was exceeding the permissible limit of Indian Minimum Seed Certification Standards (0.25%) for quality wheat seed production. For Karnal bunt, the infected samples were 281 (33.09%) and rejected samples were 4 (0.47%) having infection more than 0.25 per cent. While the infected samples for black point were 740 (87.16%). The maximum average infection of Karnal bunt was found in Karnal (0.413%), Hisar (0.278%) and Kurukshetra (0.273%) and the minimum was recorded in Sirsa (0.012%), Ambala (0.077%) and Fatehabad (0.104%). Maximum average infection of black point was found in Sonipat (0.218%) followed by Fatehabad (0.189%) and lowest was found in Ambala (0.042%) followed by Kurukshetra (0.082%).

Genome-Wide Association Study of Kernel Black Point Resistance in Chinese Wheat Landraces.

Black point (BP) disease of wheat has become a noticeable problem in China. The symptoms are spots that are brown to black in color around the wheat kernel embryo or in the endosperm, resulting in a significant reduction of wheat grain quality. Here, we evaluated 272 Chinese wheat landraces for BP reaction and performed a genome-wide association study to identify BP resistance quantitative trait loci (QTLs) in five field environments without artificial inoculation. The BP incidence data showed continuous distributions and had low to moderate correlations between environments (r = 0.094 to 0.314). Among the 272 landraces, 11 had 0.1 to 4.9%, 144 had 5 to 14.9%, 100 had 15 to 29.9%, and 17 had >30% incidence. We found three resistant accessions: WH094 (3.33%), AS661463 (2.67%), and AS661231 (2.67%), which can be used in breeding programs to enhance BP resistance. We identified 11 QTLs, which explained 8.22 to 10.99% phenotypic BP variation, and mapped them to eight wheat chromosomes. Three of the QTLs were novel. The molecular markers for the BP resistance could facilitate molecular breeding for developing BP-resistant cultivars.

In vitro antagonistic activity of Trichoderma spp. against fungal pathogens causing black point disease of wheat

Black point disease of wheat contributes to high economic losses every year. The overuse of fungicides resulted in pathogenic fungal resistance, health and environmental hazards that necessitate the formulation of safe biocontrol agents. Dual cultural assay of Trichoderma viride and Trichoderma harzianum strains proved their highest efficiency against Alternaria alternata with inhibition percentages of 75.04 and 67.83%, while the lowest activity was detected against Drechslera halodes with growth inhibition of 51.54 and 43.92%, respectively. Alternaria alternata and D. halodes strains exhibited carbendazim resistance, while Fusarium proliferatum was the most susceptible one. Chemical analysis of T. harzianum and T. viride extracts using gas chromatography-mass spectrometry indicated that 6-pentyl-α-pyrone and cyclooctanol compounds were the main active constituents representing about 26.43 and 32.74% respectively. The tested bioagents were highly effective against the fungal strains causing black point disease of wheat so that these biocontrol agents could be used in formulation of natural fungicides avoiding the harmful impact of the synthetic fungicides. Abbreviations: FCZ; Fluconazole Antifungal agent, GC-MS; Gas chromatography-Mass spectrometry, MIC; Minimum inhibitory concentration, MFC; Minimum fungicidal concentration, PDA; Potato dextrose agar, T.H; Trichoderma harzianum, 1. T. V; Trichoderma viride

SNP-based identification of QTL for resistance to black point caused by Bipolaris sorokiniana in bread wheat

Black point disease caused by Bipolaris sorokiniana is a problem in wheat production worldwide. We aimed to identify major quantitative trait loci (QTL) for resistance to black point and develop molecular markers for marker-assisted selection (MAS). A recombinant inbred line (RIL) population derived from a cross between Wanyuanbai 1 (susceptible) and SN4143 (resistant) was evaluated for black point response at three locations during two years under artificial inoculation with B. sorokiniana, providing data for six environments. Thirty resistant and 30 susceptible RILs were selected to form resistant and susceptible bulks, respectively, that were genotyped by the wheat 660K SNP array; 685 single-nucleotide polymorphisms (SNPs) were identified, among which 385 (56.2%) and 115 (16.8%) were located on chromosomes 4A and 2B, respectively. Bulked segregant RNA-Seq analysis identified candidate regions on chromosomes 4A (4.60–40.28 Mb) and 5A (1.22–48.47 Mb). Genetic linkage maps were constructed for chromosomes 2B, 4A, and 5A using 59 polymorphic dCAPS and SSR markers. Finally, two QTL, designated QBB.hau-4A and QBB.hau-5A, were detected on chromosomes 4A and 5A, respectively. The resistance allele of QBB.hau-4A was derived from SN4143, and that of QBB.hau-5A came from Wanyuanbai 1. QBB.hau-4A with a large and consistent effect (15.1%) is likely to be a new locus for black point resistance. The markers linked to QBB.hau-4A and QBB.hau-5A have potential application in MAS-based breeding.

Advances in genetic studies of black point disease in wheat

Black point disease seriously affects wheat production around the world. Because the incidence of black point is influenced by both pathogens and the environments, selecting resistant wheat lines and then breeding resistant cultivars under natural field conditions are not reliable, and assessment of disease resistance through inoculation of pathogens under controlled environments is time-consuming and laborious. One effective method to develop wheat cultivars resistant to black point is through molecular marker-assisted selection (MAS). Wheat resistance against black point is determined by quantitative trait loci (QTL) with broad-sense heritabilities of black point incidence in a range of 0.52–0.78. One hundred and ten loci for black point resistance have been identified on all wheat chromosomes. Among them, homoeologous groups 2 and 5 chromosomes contain the most loci, with 21 and 19, respectively, and homoeologous group 6 chromosomes have the fewest loci (11). The A, B, and D genomes contain 34, 41, and 35 loci, respectively. Although many loci for black point resistance have been reported, the effects of major loci are not clear. Further, because of the lack of molecular markers and resistant germplasms screened by pathogen inoculation under controlled conditions, breeding wheat cultivars resistant to black point is still difficult. In this review, these major problems were examined, and suggestions on identifying pathogens and using accurate assessment technology are proposed. It will be conducive to develop molecular markers closely linked to major loci and create resistant germplasms through MAS, which will promote the progress in resistance breeding and the control of black point in wheat.

Bipolaris sorokiniana-Induced Black Point, Common Root Rot, and Spot Blotch Diseases of Wheat: A Review.

Wheat is among the ten top and most widely grown crops in the world. Several diseases cause losses in wheat production in different parts of the world. Bipolaris sorokiniana (teleomorph, Cochliobolus sativus) is one of the wheat pathogens that can attack all wheat parts, including seeds, roots, shoots, and leaves. Black point, root rot, crown rot and spot blotch are the main diseases caused by B. sorokiniana in wheat. Seed infection by B. sorokiniana can result in black point disease, reducing seed quality and seed germination and is considered a main source of inoculum for diseases such as common root rot and spot blotch. Root rot and crown rot diseases, which result from soil-borne or seed-borne inoculum, can result in yield losses in wheat. Spot blotch disease affects wheat in different parts of the world and cause significant losses in grain yield. This review paper summarizes the latest findings on B. sorokiniana, with a specific emphasis on management using genetic, chemical, cultural, and biological control measures.

Recognizing black point in wheat kernels and determining its extent using multidimensional feature extraction and a naive Bayes classifier

Accurately identifying black point disease in wheat kernels from random samples within digital images is a fundamental and challenging task in disease identification. The performance of traditional methods is satisfactory in homogeneous environments, but their performance decreases when they are applied to images acquired in dynamic ones. In this paper, a multifeature-based machine learning method is proposed to identify and evaluate the incidence of black point disease. Ten wheat cultivars with different resistances to disease were selected to verify the accuracy of the method. First, a marker-based watershed algorithm was used to separate wheat kernels from the background to accomplish the coarse segmentation. After patches were generated from the coarse segmentation results, the patches were labeled manually and divided into two categories: black point areas and healthy areas. Gabor and Canny operators were used for texture and shape features respectively to build a feature matrix. Then, a classification model based on a naive Bayes classifier was trained to recognize the differences between the two types of patches by their features. The proposed model finally achieved the correct classification of each pixel from the testing sample and output the results in the form of a binary image, thus accomplishing the segmentation of the image. Finally, the severity of the disease was calculated according to the proportion of minimum circumscribed areas of the disease and the total area of the wheat kernel. Through the above operations, the incidence of black point disease in random samples can be determined. Five indicators, Qseg, Sr, Precision, Recall, and F-measure, were used to evaluate the segmentation effects. The average accuracy of segmentation results for the testing samples were 0.85, 0.89, 0.87, 0.86, and 83% respectively. Compared with other segmentation approaches, including the excess green method, the excess green minus excess red method, the color index of vegetation extraction, and two traditional threshold segmentation methods known as Otsu and maximum entropy threshold, the proposed algorithm had greater segmentation accuracy. Moreover, this method was demonstrated to be robust enough to be used for different illumination conditions, shooting angles, and image resolutions.

RESEARCH REGARDING THE IDENTIFICATION OF THE FUNGUS“BLACK POINT” IN SEVERAL WHEAT VARIETIES CULTIVATED IN WESTERN ROMANIA (CASE STUDY)

The wheat grains can be infected in the favourable years by fungi that are producing the disease named black point. The conditions from the climatic year 2019 in western Romania have favoured this disease, a great rateof the grains being infected. Thus, the quality of the cereals in the year 2019 was highly decreased due to the fungal infections from the genus Fusariumconnected with Alternaria. The mentioned fungi are very dangerous for the health because they are producing mycotoxins. The purpose of this research was to identify the fungi associated with black pointin four wheat varieties cultivated in near Timișoara and the setting of the frequency of the diseased grains. The analysed varieties were Exotic, Rubisco,Glosa și Lovrin 6x. The identification of the fungi implied in the black point disease was realised by laboratory analyses that were consisted in the placing of the previously sterilised wheat grains on the culture medium of agar. The samples prepared in this way were incubated at a temperature of 24 oC for 18 days. There were collected data by visual and microscopy observations at two intervals of time. Identification of the fungal growth on the grains affected by black point was done at the microscope. There were evidenced fungi from the genera Alternaria and Fusarium.The higher black point frequencies were registered in the varieties Glosa (13.51%) and Exotic (10%). In the variety Lovrin 6x, the frequency of the black point diseased grains was 9.03%. The lowest black point frequency was registered in the variety Rubisco (6.10%). The great fungal contamination rate was comprised between 88.23% inthe variety Rubisco and 100% in the variety Lovrin 6x. The wheat grains were contaminated in a high rate with the fungus Fusarium graminearumin the climatic conditions of the year 2019 that was favourable for the infection.

Natural occurrence of Alternaria mycotoxins in wheat and potential of reducing associated risks using magnolol.

Wheat is one of three major food crops in China. Alternaria species can cause spoilage of wheat with consequent mycotoxin accumulation. Alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA) are the most common and frequently studied mycotoxins. There are limited regulations placed on Alternaria mycotoxin concentrations worldwide due to the lack of toxicity data available. More data on the levels of mycotoxin contamination are also needed. It is also important to reduce the risks of Alternaria mycotoxins. One hundred and thirty-two wheat samples were collected from Hebei Province, China, and analyzed for AOH, AME, and TeA. Tenuazonic acid was found to be the predominant Alternaria mycotoxin, especially in flour samples. Studying Alternaria species that cause black-point disease of wheat indicated that Alternaria alternata and Alternaria tenuissima were the dominant species. Most of the Alternaria strains studied produced more than one mycotoxin and TeA was produced at the highest concentration, which may have resulted in the high level of TeA contamination in the wheat samples. Furthermore, magnolol displayed obvious antifungal and antimycotoxigenic activity against Alternaria. This is the first report on the antimycotoxigenic activity of magnolol against Alternaria species. The Alternaria mycotoxin contamination levels in wheat and wheat products from Hebei Province, China, were correlated with the toxigenic capacity of the Alternaria strains colonizing the wheat. Considering its safety, magnolol could be developed as a natural fungicide in wheat, or as a natural alternative food preservative based on its strong antifungal and antimycotoxigenic activity against Alternaria strains. © 2020 Society of Chemical Industry.

Assessing Genetic Resistance in Wheat to Black Point Caused by Six Fungal Species in the Yellow and Huai Wheat Area of China.

The most effective and environmentally sustainable method for controlling black point disease of wheat (Triticum aestivum L.) is to plant resistant cultivars. To identify sources of resistance to black point, 165 selected cultivars/lines were inoculated with isolates of six fungal species (Bipolaris sorokiniana, Alternaria alternata, Fusarium equiseti, Exserohilum rostratum, Epicoccum sorghinum, and Curvularia spicifera) known to cause black point in wheat using spore suspensions under controlled field conditions in 2016 and 2017. Inoculation of the isolates significantly increased the incidence of black point in the cultivars/lines compared with those grown under natural field conditions (NFC). The disease incidence of plants inoculated with B. sorokiniana and E. rostratum was 15.5% and 18.8% in 2016, and 20.4% and 23.0% in 2017, whereas those under NFC were 5.7% (2016) and 1.5% (2017), respectively. Furthermore, disease symptoms varied with pathogen. Among the 165 cultivars/lines tested, 3.6%, 50.9%, 60.0%, 1.8%, 47.3%, and 58.8% were resistant to B. sorokiniana, A. alternata, F. equiseti, E. rostratum, E. sorghinum, and C. spicifera, respectively. In addition, we identified one line ('SN530070') resistant to black point caused by all six pathogens. This is the first study to assess resistance to wheat black point caused by six fungal species under controlled conditions. The black point-resistant cultivars/lines could be useful in breeding and also in research on the mechanisms of resistance to black point.

Effect of treatment of common spring wheat crops with supramolecular complexes of tebuconazole on seed quality

The effect of treatment of crops with supramolecular complexes of tebuconazole with plant polysaccharides on the infection and germination of spring wheat grain of a new harvest was studied. The experiment (2018, 2019) was conducted on the crops of varieties Novosibirskaya 31 and Obskaya 2 in the forest-steppe zone of Western Siberia. Crops were treated in the earing phase with tebuconazole mechanocomplexes with licorice root extract (ratio 1: 5, 1:10) and arabinogalactan (1:10) with a flow rate of 0.5 kg/ha. There was a decrease in the development of spike septoria in Novosibirskaya 31 by 97.6-98.5%, in Obskaya 2 by 78.6-98.9%. The biological effectiveness of the application of commercial fungicide Folicur, CE (active ingredient tebuconazole, 250 g/l, consumption rate 1 l/ha) was at a comparable level – 98.5 and 96.8-99.6%, respectively. Tebuconazole complexes with plant polysaccharides proved to be effective in inhibiting black point disease of wheat. Annually, the number of affected wheat caryopses was 1.54 and 1.50 times lower in Novosibirskaya 31 variety and 1.4-1.2 times lower in Obskaya 2 variety in the crops protected by tebuconazole with arabinogalactan compared to the treatment with Folicur, CE. Treatment with mechanocomplexes contributed to the reduction of seed contamination with phytopathogens. Complexes of tebuconazole with licorice root extract and arabinogalactan reduced the rate of infection with helminthosporiasis by 3.8 and 1.7 times (Folicur, CE – 5.5 times). Annually, seed contamination with Fusarium spp. was 8.3 and 3.7 times lower than in the control due to crop protection measures ensured by tebuconazole with arabinogalactan and licorice root extract. In the variants with the use of mechanocomplexes, seed infection with Penicillium spp. decreased. The biological effectiveness of tebuconazole with licorice root extract (1 : 5) was 69.9%, with arabinogalactan (1 : 10) – 58.1%, Folicur, CE – 67.7%. The best germination rate (95.0 and 89%), exceeding that of the standard, was obtained when both wheat varieties were treated with a complex of tebuconazole with licorice root extract (1 : 5). The complexes of tebuconazole with licorice root extract and arabinogalactan created by the mechanochemical method aiming to protect wheat plants from leaf diseases can have a significant healing effect on the emerging grain, improving its sowing qualities

Genetic diversity of Alternaria species associated with black point in wheat grains.

The genus Alternaria is a widely distributed major plant pathogen that can act as a saprophyte in plant debris. Fungi of this genus frequently infect cereal crops and cause such diseases as black point and wheat leaf blight, which decrease the yield and quality of cereal products. A total of 25 Alternaria sp. isolates were collected from germ grains of various wheat cultivars from different geographic regions in Kazakhstan. We investigated the genetic relationships of the main Alternaria species related to black point disease of wheat in Kazakhstan, using the inter-primer binding site (iPBS) DNA profiling technique. We used 25 retrotransposon-based iPBS primers to identify the differences among and within Alternaria species populations, and analyzed the variation using clustering (UPGMA) and statistical approaches (AMOVA). Isolates of Alternaria species clustered into two main genetic groups, with species of A.alternata and A.tennuissima forming one cluster, and isolates of A. infectoria forming another. The genetic diversity found using retrotransposon profiles was strongly correlated with geographic data. Overall, the iPBS fingerprinting technique is highly informative and useful for the evaluation of genetic diversity and relationships of Alternaria species.

The relationship between black point disease and Total Grain Weight (TGW) in some winter wheat (bread wheat) cultivars

The relationship between black point disease and Total Grain Weight (TGW) in some winter wheat (bread wheat) cultivars

EFFECT OF SEED DRESSING CHEMICALS ON EMERGENCE, YIELD AND AGAINST SOIL & SEED BORN DISEASES OF WHEAT

Field studies were carried out at Adaptive Research Farm, Sheikhupura Punjab, Pakistan having rice- wheat cropping system to evaluate the efficacy of three different fungicides against seed or soil borne wheat diseases (Root rot, Loose smut & Black Point disease) during two successive seasons 2015-16 & 2016-17.The fungicides were Thiophenate methyl, compound fungicides i.e. Tubeconzol+ imidachloprid and Difenoconazol + cypnoconazol used as seed treatment at the rate of 2.5 g , 4 ml & 1 ml per kg of seed respectively. Incidence of root rot, loose smut & black point disease was recorded by selecting 15 plants, 100 plants & 100 seeds randomly of each treatment from each plot respectively in comparison with untreated control. All the fungicides significantly increased the seedling emergence per square meter about 15 percent as compared to untreated plot. Tubeconzol+ imidachloprid and Difenoconasol +cypnoconazol were the most effective seed dressing fungicide and reduced the number of rotted roots , loose smut infected spikes and black point infested seeds. Maximum number of productive tillers per square meter, healthy grains per spike and yield kg per hectare were recorded with compound fungicide Tubeconzol+ Imidachloprid followed by Difenoconazol + Cypnoconazol treated plots as compared to untreated plot.

Isolation and identification of the fungus Alternaria alternata from some wheat fields and the investigation of some of produced the toxins

This study was conducted for the purpose of isolating and Identifing the fungus Alternaria alternata isolation from some wheat fields and investigating some of the toxins produced by the fungus A. alternata . The results of some field survey of Najaf province revealed that the incidence of black point disease on the wheat caused by the fungus A. alternata ranged between 13 - 70% .The study showed identification of a new isolate of the fungus A.alternata that has been registered in the National Center for Biotechnology Information (NCBI), under the name: Najaf and under the accession number KX350052.1. The results of the toxicity test using HPLC and GC-MAS showed that the Najaf isolate is able to produce three types of toxins:namely alteratoxin II (ATX II), alternariol (AOH) and alternariol mono methyl ether (AME).

DURUM WHEAT RESISTANCE TO BLACK POINT

The search for effective sources of wheat immunity to common diseases in the Altai Region and the inclusion of the most valuable donors in breeding programs are the most important components of a strategy to create new varieties resistant to pathogens. The black point disease causing the darkening the grain germ is found in all regions where Triticum durum Desf. is cultivated. We studied 58 varieties and lines of spring durum wheat of different geographic origin for resistance to black point in the Priobskaya (the Ob River) forest-steppe of the Altai Region. A wide range of genotypes on the resistance to the disease was revealed. Growing season conditions were comparable with genotype contribution to the manifestation of black point: the proportion of the influence of "genotype" and "growing conditions" factors accounted for 45.8 and 41.1%, respectively. Interaction of the factors was 13.1%. Accessions with the lowest development of infection have been identified. Varieties from Altai Research Institute of Agriculture, Orenburg Research Institute of Agriculture, Donۥs Zonal Research Institute of Agriculture, Siberian Research Institute of Agriculture are characterized by a low level of black point damage (5.84 – 7.36%). The sources of resistance, according to the economic and biological evaluation have no negative characteristics and properties that prevent their using in programs for resistance to black point.

Identification of cyclic lipopeptides produced by Bacillus vallismortis R2 and their antifungal activity against Alternaria alternata.

To identify the different antifungal biomolecules produced by isolate Bacillus vallismortis R2 and analyse their effect on Alternaria alternata, a common pathogen causing black point disease of wheat. The different antifungal molecules produced by isolate R2 were purified by column chromatography. The liquid chromatography-mass spectrometry of purified fractions confirmed the ability of R2 to produce biomolecules putatively similar to three different families of cyclic lipopeptides (CLPs) viz. surfactins, iturins and fengycins. The synergistic interaction among CLPs was evident from significant increase in the antifungal activity of mixture of purified fractions as compared to that of the individual fractions by agar well diffusion assay. The evaluation of antifungal activity of purified fractions by 96-well microtitre plate assay showed that the fengycin-like molecules supported significantly higher antifungal activity against A.alternata than iturin A and no antifungal activity was supported by surfactin. The isolate R2, producing different CLPs, can be used as an environmental friendly alternative to chemical fungicides. Among the three different CLPs viz. surfactin, iturin A and fengycin produced by R2, the fengycins were the most active lipopeptides. This is the first report on co-production of three different types of CLPs by the cells of B.vallismortis.

Biological control of pathogens associated with kernel black point disease of wheat

Pathogens associated with wheat kernel black-point disease were recovered from symptomatic grains and identified as Cochliobolus sativus, Alternaria alternata and Fusarium graminearum. A total of twenty-five microbial isolates obtained from the surface of healthy grains of wheat were screened for antagonism against the isolated pathogens. The most effective antagonistic isolates were Bacillus megaterium (B5), B. amyloliquefaciens (B28), Trichoderma harzianum (T37) and Epicoccum sp. (E52). In pots, treating of wheat grains with strains B5, B28, T37 and E52 significantly improved germination and seedling growth naturally infected with the black-point pathogens. Bacillus amyloliquefaciens (strain B28) was the most efficient biocontrol agent in terms of germination, length of roots and shoots which increased by 103.2, 55.3 and 43.91%, respectively. In field trials, the antagonistic isolates improved germination and tillering of black-pointed wheat grains. Spraying wheat plants with the antagonistic isolates significantly decreased the incidence of leaf-spots and kernel black-point down to 18.7 and 2.86, respectively, with B. amyloliquefaciens (B28). In addition, grain yield was significantly increased. Strain B28 (B. amyloliquefaciens) increased the weight of 1000-kernels by 16.77% and was as effective as the fungicide Sumi-8.