Common Root Rot Of Wheat Research Articles

A review on common root rot of wheat and barley in Australia

AbstractCommon root rot (CRR) caused by the soilborne pathogen Bipolaris sorokiniana (teleomorph Cochliobolus sativus) is becoming increasingly prevalent worldwide. Identification of CRR is difficult and time‐consuming for human assessors due to the non‐distinctive above‐ground symptoms, with browning of subcrown internodes and roots the most distinguishing symptom of infection. CRR disease has been recognized as a significant disease for cereal crops in many countries. In 2009, CRR in Australia was estimated to cause $30 million average annual yield loss for wheat and $13 million for barley. Recent evidence indicates CRR may be more prevalent than expected in Australian wheat cropping areas due to lack of research on this disease. Low levels of B. sorokiniana survive in the soil for up to 10 years and attack plants at early stages of growth. Therefore, mitigating CRR in wheat and barley may not be practical at the late stages of infection due to lack of effective methods; however, early detection might be viable to alleviate the impact of this disease. A comprehensive overview of CRR caused by B. sorokiniana, including disease background, worldwide economic losses, management methods, potential CRR detection using multispectral and hyperspectral sensors and the research focus over the past 50 years is provided in this article. This review paper is expected to provide thorough supplemental information for current studies about CRR and proposes recommendations for whole‐of‐field disease scouting methods to farmers, enabling reduced time and cost for CRR management and increasing wheat and barley production worldwide.

A seed-endophytic bacterium NEAU-242-2: Isolation, identification, and potential as a biocontrol agent against Bipolaris sorokiniana

Currently, common root rot of wheat has caused significant yield losses worldwide. Biological control is an important method to control common root rot of wheat. An endophytic bacterium, strain NEAU-242-2 was isolated from wheat seeds, which showed the strongest inhibitory activity against Bipolaris sorokiniana (84.2%) and also had strong broad-spectrum antifungal activity, with the inhibition rates over 61.2% against all phytopathogens used in this study except for Rhizoctonia solani (44.5%), and was identified as Bacillus velezensis by 16S rRNA gene sequence and whole genome sequence and average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values. Pot experiments showed that strain NEAU-242-2 exhibited significant biocontrol effect (80.61 ± 1.22%) on common root rot of wheat in greenhouse. Furthermore, the sterile culture filtrate of strain NEAU-242-2 had strong inhibitory activity (86.96 ± 3.02%) against B. sorokiniana and the main antifungal substance was preliminarily identified as lipopeptides. The crude lipopeptide extracted from strain NEAU-242-2 showed strong antifungal activity (61.45 ± 3.45%) against B. sorokiniana with the IC50 of 25.93 µg/mL, and could cause mycelial wrinkle, fracture, and dehydrated malformation, destroy the structure of cell, and lead to cellular malformation and the disappearance of most membrane-like structures. Besides that, strain NEAU-242-2 could also conspicuously promote wheat seed germination and seedling growth. The fungistasis and plant growth-promoting activity of strain NEAU-242-2 were found to be associated with the production of IAA (19.4 ± 0.6 µg/mL), siderophores, nitrogenases, cell wall-degrading enzymes (proteases and cellulases), and other active secondary metabolites. Additionally, a large number of genes related to antifungal and plant growth-promoting traits were also identified in the whole genome of strain NEAU-242-2. These results indicated that strain NEAU-242-2 had the potential as a biocontrol agent for B. sorokiniana.

Genetics of Resistance to Common Root Rot (Spot Blotch), Fusarium Crown Rot, and Sharp Eyespot in Wheat.

Due to soil changes, high density planting, and the use of straw-returning methods, wheat common root rot (spot blotch), Fusarium crown rot (FCR), and sharp eyespot (sheath blight) have become severe threats to global wheat production. Only a few wheat genotypes show moderate resistance to these root and crown rot fungal diseases, and the genetic determinants of wheat resistance to these devastating diseases are poorly understood. This review summarizes recent results of genetic studies of wheat resistance to common root rot, Fusarium crown rot, and sharp eyespot. Wheat germplasm with relatively higher resistance are highlighted and genetic loci controlling the resistance to each disease are summarized.

Synergistic Action of Commercially Available Fungicides for Protecting Wheat from Common Root Rot Caused by Bipolaris sorokiniana in China.

Wheat (Triticum aestivum) common root rot (CRR) caused by predominant fungal pathogen Bipolaris sorokiniana occurs in all wheat-growing regions worldwide and is difficult to control. In this study, the efficacy of eight fungicides against Bipolaris sorokiniana was examined in in vitro assays, and we determined that the combined application of two fungicides significantly inhibits the growth of fungal mycelium. Half of the maximal effective concentration of a mixture containing fludioxonil and difenoconazole in the ratio 1:4 was 0.0372 mg/liter, and the cotoxicity coefficient was 160.14. Under an environmentally controlled pot assay, seed treatment with the mixture of fludioxonil and difenoconazole in the 1:4 ratio demonstrated the best control efficiency at seedling and adult stages, respectively. The best synergistic mixture on seed treatment was assessed in a 2-year field experiment at Hebei, China. The best control efficacy achieved at the seedling and adult stages was 82.65% and 68.48%, respectively. Overall, the in vitro mycelial growth inhibition assay and controlled-environment and field studies indicated that the synergistic action of a mixture of fludioxonil and difenoconazole provides effective control against wheat CRR. These findings highlight the potential application of the fungicide combination for controlling CRR and reducing the selection pressure on fungal pathogens by lessening the use of various fungicides in the field.

Molecular and pathogenic characterization of Cochliobolus anamorphs associated with common root rot of wheat in Azerbaijan

Genetic variation among the Azerbaijani isolates of anamorphs of Cochliobolus spp., the causal agents of common root rot of wheat, was evaluated using pathogenicity assessments, sequence analyses of the internal transcribed spacer (ITS) region and glyceraldehyde-3-phosphate dehydrogenase (GPDH) gene, as well as inter-simple sequence repeat (ISSR) and inter-primer binding site (iPBS) markers. Twenty-eight isolates used in this study were obtained from diseased wheat plants in cereal growing regions of Azerbaijan in 2017. Bipolaris sorokiniana, Curvularia spicifera, and Curvularia inaequalis were identified. Bipolaris sorokiniana isolates were the most virulent on wheat seedlings, followed by isolates of C. spicifera and C. inaequalis. Phylogenetic analyses of a combined dataset of the ITS and GPDH regions grouped the isolates into three clusters, each of which contained isolates of one species. The dendrogram derived from the unweighted pair-grouped method by arithmetic average (UPGMA) cluster analyses based on the data of ISSR and iPBS markers divided the isolates into three clusters in concordance to their taxonomic grouping at species level, but without correlation to their geographic origins. Population structure of isolates was estimated based on Bayesian modelling, and this showed three populations (K = 3) supporting the separation of isolates in the dendrogram with the greatest mean value of Ln likelihood (-893,8). Utilization of the markers either separately or together produced a high level of polymorphism at interspecies level, which allowed for the separation of species. Although both marker systems had similar discrimination power to reveal genetic differences among the species, ISSR markers were more informative for eliciting intraspecies polymorphisms within B. sorokiniana and C. spicifera isolates. This is the first study on genetic diversity and population structure of anamorphic stages of Cochliobolus associated with common root rot of wheat using iPBS markers.

The screening and identification of the biological control fungi Chaetomium spp. against wheat common root rot.

Bipolaris sorokiniana is a soil-borne fungal pathogen causing common root rot in wheat, and is difficult to control through chemical and agricultural means. Chaetomium spp. have been documented as potential biological control agents for plant diseases. In this study, seven Chaetomium strains were screened for their abilities to control B. sorokiniana on agar plates. Strain 22-10 significantly inhibited the growth of B. sorokiniana on potato dextrose agar plates, up to 66.7%. Its filtrate of liquid culture also inhibited the mycelial growth of B. sorokiniana, indicating that strain 22-10 produced secondary metabolites against B. sorokiniana. The incidence and disease indexes of common root rot significantly decreased in wheat after treatment with the crude extract of strain 22-10. Six active compounds were purified from crude extract of this fungus culture against B. sorokiniana. Chaetoviridin A showed the highest efficiency to inhibit the growth of B. sorokiniana. Strain 22-10 was identified as Chaetomium globosum based on phylogenetic analysis of the rDNA internal transcribed spacer region and microscopic characteristics. The high control efficiency of strain 22-10 of C. globosum against B. sorokiniana suggested it has potential to be a biocontrol agent for B. sorokiniana.

Glyphosate associations with cereal diseases caused by Fusarium spp. in the Canadian Prairies

Fusarium pathogens cause important diseases, such as root/crown rot and Fusarium head blight (FHB), in cereal crops. These diseases can be caused by similar Fusarium spp. Common root rot (CRR) is widespread in the western Canadian Prairies, whereas FHB has potential of becoming an important disease in this region. There are no commercially available cereal cultivars with good resistance to these diseases. It is therefore important to identify agronomic practices that could affect levels of Fusarium pathogens in cereals. This review deals primarily with the effects of tillage systems and glyphosate use on the development of FHB and CRR in wheat and barley in eastern Saskatchewan. Although the FHB study in 1999–2002 indicated that environment was the most important factor determining FHB development, previous glyphosate use and tillage practice were among the production factors with the greatest association with FHB. Overall, disease was highest in crops under minimum-till management. Previous glyphosate use was consistently associated with higher FHB levels caused by the most important FHB pathogens, Fusarium avenaceum and Fusarium graminearum. Cochliobolus sativus, the most common CRR pathogen, was negatively associated with previous glyphosate use, while F. avenaceum, F. graminearum, and other fungi were positively associated, suggesting that glyphosate might cause changes in fungal communities. The occurrence and isolation of F. avenaceum from cereal residues were greater under reduced-till than conventional-till while C. sativus was most common under conventional-till, and F. graminearum was lowest under zero-till. Previous glyphosate applications were again correlated positively with F. avenaceum and negatively with C. sativus. These observations agreed with results from the FHB and CRR studies. These are the first studies that established a relationship between previous glyphosate use and increased Fusarium infection of spikes and subcrown internodes of wheat and barley, or Fusarium colonization of crop residues. However, because of the close association between noncereal crops, reduced tillage and glyphosate use, it was not possible to completely separate the effects of these factors on Fusarium infections. Determining the relative contribution of these popular production trends to the development of diseases caused by Fusarium spp. are essential for devising appropriate agronomic recommendations to prevent their further spread in western Canada, and to reduce the impact that these diseases are having in areas where they are already established. The consistent association between previous glyphosate use and Fusarium infections also warrants further research to elucidate the nature of this association and the underlying mechanisms determining these effects.

Sustaining productivity of a Vertosol at Warra, Queensland, with fertilisers, no-tillage or legumes. 7. Yield, nitrogen and disease-break benefits from lucerne in a two-year lucerne - wheat rotation

Continuous cultivation and cereal cropping of southern Queensland soils previously supporting native vegetation have resulted in reduced soil nitrogen supply, and consequently decreased cereal grain yields and low grain protein. To enhance yields and protein concentrations of wheat, management practices involving N fertiliser application, with no-tillage and stubble retention, grain legumes, and legume leys were evaluated from 1987 to 1998 on a fertility-depleted Vertosol at Warra, southern Queensland. The objective of this study was to examine the effect of lucerne in a 2-year lucerne–wheat rotation for its nitrogen and disease-break benefits to subsequent grain yield and protein content of wheat as compared with continuous wheat cropping.Dry matter production and nitrogen yields of lucerne were closely correlated with the total rainfall for October–September as well as March–September rainfall. Each 100 mm of total rainfall resulted in 0.97 t/ha of dry matter and 26 kg/ha of nitrogen yield. For the March–September rainfall, the corresponding values were 1.26 t/ha of dry matter and 36 kg/ha of nitrogen yield. The latter values were 10% lower than those produced by annual medics during a similar period. Compared with wheat–wheat cropping, significant increases in total soil nitrogen were observed only in 1990, 1992 and 1994 but increases in soil mineralisable nitrogen were observed in most years following lucerne. Similarly, pre-plant nitrate nitrogen in the soil profile following lucerne was higher by 74 kg/ha (9–167 kg N/ha) than that of wheat–wheat without N fertiliser in all years except 1996. Consequently, higher wheat grain protein (7 out of 9 seasons) and grain yield (4 out of 9 seasons) were produced compared with continuous wheat. There was significant depression in grain yield in 2 (1993 and 1995) out of 9 seasons attributed to soil moisture depletion and/or low growing season rainfall. Consequently, the overall responses in yield were lower than those of 50 kg/ha of fertiliser nitrogen applied to wheat–wheat crops, 2-year medic–wheat or chickpea–wheat rotation, although grain protein concentrations were higher following lucerne.The incidence and severity of the soilborne disease, common root rot of wheat caused by Bipolaris sorokiniana, was generally higher in lucerne–wheat than in continuous wheat with no nitrogen fertiliser applications, since its severity was significantly correlated with plant available water at sowing. No significant incidence of crown rot or root lesion nematode was observed. Thus, productivity, which was mainly due to nitrogen accretion in this experiment, can be maintained where short duration lucerne leys are grown in rotations with wheat.

The Canadian Phytopathological Society Annual Meeting, Montréal, Quebec, 2003

The Canadian Phytopathological Society Annual Meeting, Montréal, Quebec, 2003

Diagnosis of Common Root Rot of Wheat and Barley

Diagnosis of common root rot of wheat and barley is discussed in detail, including its symptoms and signs, host range, taxonomy, and geographic distribution, as well as methods of isolation, identification, and storage of the common root rot pathogen. Accepted for publication 17 July 2003. Published 19 August 2003.

Abstracts, The Canadian Phytopathological Society, annual meeting, Montreacute;al, Quebec, 1999

Abstracts, The Canadian Phytopathological Society, annual meeting, Montreacute;al, Quebec, 1999

Sustaining productivity of a Vertisol at Warra, Queensland, with fertilisers, no-tillage, or legumes. 5. Wheat yields, nitrogen benefits and water-use efficiency of chickpea-wheat rotation

Summary. In this study, the benefits of chickpea–wheat rotation compared with continuous wheat cropping (wheat–wheat rotation) were evaluated for their effects on soil nitrate nitrogen, wheat grain yields and grain protein concentrations, and water-use efficiency at Warra, southern Queensland from 1988 to 1996. Benefits in terms of wheat grain yields varied, from 17% in 1993 to 61% in 1990, with a mean increase in grain yield of 40% (825 kg/ha). Wheat grain protein concentration increased from 9.4% in a wheat–wheat rotation to 10.7% in a chickpea–wheat rotation, almost a 14% increase in grain protein. There was a mean increase in soil nitrate nitrogen of 35 kg N/ha.1.2 m after 6 months of fallow following chickpea (85 kg N/ha) compared with continuous wheat cropping (50 kg N/ha). This was reflected in additional nitrogen in the wheat grain (20 kg N/ha) and above-ground plant biomass (25 kg N/ha) following chickpea. Water-use efficiency by wheat increased from a mean value of 9.2 kg grain/ha. mm in a wheat–wheat rotation to 11.7 kg grain/ha.mm in a chickpea–wheat rotation. The water-use efficiency values were closely correlated with presowing nitrate nitrogen, and showed no marked distinction between the 2 cropping sequences. Although presowing available water in soil in May was similar in both the chickpea–wheat rotation and the wheat–wheat rotation in all years except 1996, wheat in the former used about 20 mm additional water and enhanced water-use efficiency. Thus, by improving soil fertility through restorative practices such as incorporating chickpea in rotation, water-use efficiency can be enhanced and consequently water runoff losses reduced. Furthermore, beneficial effects of chickpea in rotation with cereals could be enhanced by early to mid sowing (May–mid June) of chickpea, accompanied by zero tillage practice. Wheat of ‘Prime Hard’ grade protein (≥13%) could be obtained in chickpea–wheat rotation by supplementary application of fertiliser N to wheat. In this study, incidence of crown rot of wheat caused by Fusarium graminearum was negligible, and incidence and severity of common root rot of wheat caused by Bipolaris sorokiniana were essentially similar in both cropping sequences and inversely related to the available water in soil at sowing. No other soil-borne disease was observed. Therefore, beneficial effects of chickpea on wheat yields and grain protein were primarily due to additional nitrate nitrogen following the legume crop and consequently better water-use efficiency.

Crown rot and common root rot in wheat grown under different tillage and stubble treatments in southern Queensland, Australia

In southern Queensland, crown rot caused by Fusarium graminearum Group 1 and common root rot caused by Bipolaris sorokiniana are common soilborne diseases of wheat and barley. The incidence of these diseases was measured in the susceptible wheat ( Triticum aestivum L.) cultivar, Hartog which was grown under no tillage, reduced tillage (two tillage operations plus herbicides) and where stubble was retained or removed by burning (1984–1986) or physically removed (1987–1993). Primary tillage was with blade, disc or chisel implements. The level of crown rot and common root rot was higher where stubble was retained than where it was removed. There was a significant interaction in incidence of crown rot between stubble management and some types of tillage. Where there was no tillage, incidence of crown rot was significantly higher where stubble was retained (32.2%) than where it was removed (4.7%) whereas under disc tillage, there was no significant difference in disease level between stubble treatments (12–17%). Incidence of crown rot was not affected by the type of tillage employed. The incidence of deadheads (heads without grain) caused by crown rot was lowest in the no tillage plots (4.3%) and highest in the reduced (19.3%) and conventional (12.2%) disc tillage stubble retained treatments. Available soil water (depth of 1.2 m) at sowing and anthesis was lowest in the conventional disc stubble retained plots and highest in the no tillage stubble retained plots. It is hypothesised that the high levels of deadheads were due to moderate to high levels of disease and low available soil water at planting and anthesis. Although incidence of crown rot was high under no tillage, incidence of deadheads was lower than in other treatments due to the higher availability of soil water. Severity of common root rot was lower in stubble removed, than in stubble retained, treatments and also lower in no tillage than in any of the other tillage treatments.

Role of root colonization ability of plant growth promoting fungi in the suppression of take-all and common root rot of wheat

Plant growth promoting fungal (PGPF) isolates — GS6-1, GS7-4 ( Phoma sp.) and GU23-3 (non-sporulating fungus), from zoysiagrass rhizosphere, suppressed take-all and common root rot of spring wheat caused by Gaeumannomyces graminis var. tritici (Ggt) and Cochliobolus sativus (Cs), respectively, in the greenhouse. Barley kernels colonized with pathogens (0.1%, 0.5% or 1.0% w w ) and PGPF isolates (1.0%, 1.5% or 2.0% w w ) were added to soil individually and in different combinations of pathogen and PGPF. With an increase in the rate of PGPF amendment, all three PGPF isolates suppressed take-all and common root rot ( P = 0.05), irrespective of the pathogen inoculum level. Among the PGPF isolates, GS6-1 and GS7-4 were more effective than GU23-3. When added to soil individually, PGPF isolates were recovered from 75 to 95% of root segments, and Ggt and Cs from 88–95% of root segments. Both Ggt and Cs were isolated less frequently from roots when the PGPF concentration was high (2.0%); however, the PGPF isolates were isolated from roots in high frequencies even when the pathogen inoculum level was high. Isolate GS6-1 promoted plant growth even when the pathogen inoculum rate was high, as did GS7-4, but to a lesser amount. These fungal isolates suppressed take-all and common root rot, and two of them also increased plant growth. The suppression of take-all and common root rot appeared to be due to the competitive root colonization by PGPF isolates, thus blocking sites available for infection by pathogens.

Influence of crop rotation on common root rot of wheat and barley

Influence of crop rotation on common root rot of wheat and barley

Effect of fertilizers and of liming acid soil on common root rot in wheat, and of chloride on the disease in wheat and barley

Effect of fertilizers and of liming acid soil on common root rot in wheat, and of chloride on the disease in wheat and barley

Quantification by Image Analysis of Subcrown Internode Discoloration in Wheat Caused by Common Root Rot

Common root rot of wheat, caused by Cochliobolus sativus, produces a brown to black discoloration of the subcrown internodes (SCIs). The degree of discoloration is a measure of root rot severity and is directly related to yield losses. The rating system commonly used to assess the degree of discoloration is subjective, vulnerable to inconsistencies, and limited in quantification to only four categories. This study describes an image-analysis method that reliably quantifies discoloration of SCIs. Quantification is objective, highly precise, quick, and usable with any image analyzer. Image-analysis quantifications were compared with the four-category, subjective rating system for greenhouse collections of SCIs of wheat [...]

Effect of cropping history on soil populations of Bipolaris sorokiniana and common root rot of wheat

Six winter and four summer crops, two pasture legumes and two pasture grasses, were grown in rotation with wheat in soil naturally colonized with Bipolaris sorokiniana. Soil populations of B. sorokiniana under the different rotations were measured at the beginning of winter and of summer between 1982 and 1986. Populations increased under wheat, barley and triticale, remained static under oats, safflower and chickpea, and declined under buffel grass, cocksfoot, lucerne, mung bean, snail medic, sorghum, sunflower and White French millet. Populations also declined under a fallow, and propagules of the fungus were still present after 4 years. Where populations had declined owing to cropping history, they were effectively restored to their previous levels after one wheat crop. Severity of common root rot in wheat caused by B. sorokiniana, was reduced from that occurring with continuous wheat when wheat was planted after safflower, sorghum, mung bean, snail medic, lucerne and buffel grass. Disease levels in wheat following barley, triticale, oats, chickpea, millet, sunflower, cocksfoot or a fallow were not significantly different from that of continuous wheat. When a second wheat crop was planted, severity of common root rot was high in all treatments, irrespective of the previous cropping history. The implications of these findings in developing control strategies for common root rot by crop rotation are discussed.

The effects of fumigation, rotation with lupins, and nitrogen application on plant growth and common root rot of wheat at Geraldton, Western Australia

The effects of soil fumigation (98% methyl bromide + 2% chloropicrin at 580 kg/ha) and N fertilizer (0, 12.5, 25, 50 or 100 kg N/ha) were examined in field trials on continuous wheat and wheat in rotation with lupins on the Geraldton sandplain. Fumigation increased grain yields at N fertilizer levels more or =25 kg/ha and was associated with reduced incidence and severity of common root rot (Bipolaris sorokiniana)[Cochliobolus sativus]. Grain yield was not significantly affected by rotation. Fumigation increased soil ammonium levels and decreased soil nitrate levels. Rotation of wheat and lupins increased mid-season growth at all levels of applied N but only increased grain yield where no N was applied.

Effects of Tillage on Common Root Rot of Wheat in Texas

Effects of tillage on the incidence and severity of common root rot caused by Bipolaris sorokiniana and on spore distribution were studied in continuous wheat culture at three locations in Texas. Spore populations were determined to a depth of 40 cm in 10-cm increments. The majority of spores were found in the top 10 cm of soil regardless of tillage method. Although significantly more spores were found with conventional tillage than in the no-still system, the distribution of spores in the soil profile was not significantly affected by tillage (...)