Barley Resistance to Fusarium Head Blight
Root Rot Screening Program for Barley and Triticale Germplasm and Cultivars
Purpose
To carry-out a routine field screening of germplasm of barley and spring triticale for common root rot and to use resistant lines in the germplasm development and breeding projects.
Procedure
Lines are deep-seeded in single row plots in the nursery area, which has been heavily inoculated with common root rot. Resistant and susceptible checks are grown every 10 plots. Lines are evaluated on the basis of discoloration of the subcrown internode.
Reason for project and impact
Common root rot has been estimated to take an average of 10% from barley yields on a yearly basis. Varieties with resistance to common root rot and/or avoidance of extremely susceptible varieties by breeding programs and producers would increase crop productivity, especially under frequent cereal cultivation.
Summary of results
In 2005, approximately 976 breeding lines of barley were screened for common root rot resistance. Disease assessments of 486 test plots were also performed and included as part of the disease data package for the 1st and 2nd year Cooperative Test entries and checks of the Western Cooperative Barley Registration Test.
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Foliar Disease Resistance Screening in Barley and Triticale Germplasm
Purpose
To evaluate germplasm and advanced lines of barley for reaction to scald and net blotch; evaluate triticale for reaction to tan spot; and evaluate winter wheat for septoria and powdery mildew.
Procedure
Advanced lines will be tested in screening nurseries. Both barley and triticale will be evaluated in inoculated tests at Lacombe, Edmonton, Saskatoon, and Brandon. Natural field infections will be evaluated on field tests at Olds, Calmar, Trochu, Stettler, and Lacombe. Resistant lines that are identified by the screening process will be included in the germplasm creation project to accumulate disease resistance into adapted lines. Development of screening techniques for early generation material.
Reason for project
Cereal leaf diseases reduce crop yield and quality on an annual basis. Cereal leaf disease levels are on the increase. New varieties require improved disease resistance over check varieties in order to be registered.
Summary of results
Lines identified as having superior resistance to foliar diseases are being used in the breeding program. All of the new varieties developed since 1990 have higher levels of disease resistance. Research is being cooperatively carried out by Alberta Agriculture and Agriculture & Agri-Food Canada.
Scald screening: Large-scale hill plot nurseries to screen for resistance to scald were again conducted at both Lacombe and Edmonton. The scald screening site at Edmonton was located on plot land at the University of Alberta. AAFRD breeding lines and currently registered varieties with resistance to scald were evaluated for scald resistance on three dates during the summer of 2005 starting in early July. At Lacombe the AAFRD material had average levels of disease of 5.7 with a minimum rating of 0 and a maximum rating of 9.0 on a 0-9 scale. At the Edmonton nursery site, average levels of scald were 3.5 with a minimum rating of 0 and a maximum rating of 9.0. At Lacombe, approximately 3.6% of the breeding lines had ratings equal to 0, while 13.2% had ratings of greater than zero, but less than or equal to 3, 14.9% had ratings of greater than 3, but less than or equal to 5, while 68.4% had ratings of greater than 5. At Edmonton, approximately 23.4% of the breeding lines had ratings equal to 0, while 21.1% had ratings of greater than zero, but less than or equal to 3, 20.3% had ratings of greater than 3, but less than or equal to 5, while 35.2% had ratings of greater than 5. Lines with ratings from 0-3 are generally considered to be resistant, while lines with ratings of >5 are moderately susceptible to susceptible, and lines with ratings of 4 or 5 have intermediate levels of resistance. Check lines including AC Lacombe, CDC Earl, Harrington, Manny, Merit, Niobe, Ponoka, and Seebe had ratings of 7.2, 8.1, 7.7, 1.9, 6.5, 8.0, 4.9, and 1.6, respectively, at Lacombe; while at Edmonton ratings were 4.6, 5.9, 6.0, 0.0, 7.0, 6.5, 1.3, and 0.4, respectively.
A four-replicate trial of all commercially available cultivars with some level of scald resistance was again conducted at both screening sites to assess changes in cultivar reactions and the durability of resistance. Average levels of scald in this trial were 5.7 and 3.6 on the 0-9 scale at Lacombe and Edmonton, respectively. At Lacombe, the cultivars Jaeger, Kasota, Manny, Niobe, Ponoka, Seebe, and Trochu had ratings of 6.5, 3.8, 3.0, 7.3, 3.8, 3.0, and 7.0, while Harrington had a rating of 7.3. At Edmonton, the cultivars Jaeger, Kasota, Manny, Niobe, Ponoka, Seebe, and Trochu had ratings of 4.0, 0.0, 0.0, 6.0, 0.5, 0.8, and 3.3, while Harrington had a rating of 6.0. Scald screening data were tabulated and sent to cooperating breeding programs for their information and use regarding advancement of material and the genetics of resistance.
Barley diseases in yield, coop, regional and race variation trials: The severity of leaf disease on barley, wheat and triticale was assessed in a total of 1,666 plots from coop, yield and regional tests. Scald of barley was the major leaf disease and was generally intermediate to high in severity at Calmar and Olds screening sites, but the levels of disease also varied with individual tests. The Lacombe site showed low to intermediate levels of scald and had an intermediate level of net blotch. The Trochu site was low in scald and thus no differentiation in scald reactions was possible. Net blotch was the prevalent disease in the Regional Variety 2-row and 6-row Barley Tests (B2R2L and B6R2L tests) at Lacombe. As a result, the severity of scald was assessed in the majority of tests, while net blotch was assessed in the B2R2L and B6R2L tests using a 0-9 scale. Notes were also made on other diseases if they were severe on individual entries while the dominant disease was evaluated.
A few barley plots were moderately infected by stripe rust at the Lacombe site and some plots were severely infected at the Edmonton scald nursery. Similar to the disease reactions from previous years, scald was more severe in the coop and regional trials than in the yield trials, indicating that susceptibility of the entries resulted from the lack of genetic resistance. An example of this was demonstrated by the entries HB116-118 in the coop trial, which consistently showed relatively higher levels of scald across most test locations. Most entries in the yield trials had low to moderate levels of scald except for Vivar and Xena that were rated 6 and 5, respectively, at the Calmar site. Moderate to high levels of scald resulted in the ability to differentiate scald reactions among entries in most of the tests evaluated.
The Agricore United Cooperative Test (BFC2L) test was assessed for scald for the first time and the result showed that all entries had substantially lower levels of scald compared with cvs. Sebastian and Harrington. Scald differentials in race variation tests at Lacombe and Calmar in 2005 had slightly more severe scald compared with that in 2004. Analyses will be carried out to determine if differences among years and differentials are statistically significant. The scald straw nursery had a low to moderate level of scald when cvs. Harrington and Jackson were harvested before flowering. We are experimenting to increase the number of days to grow barley for more rapid scald development, while trying to prevent seed from setting before harvesting.
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Breeding for Resistance in Barley to True Loose Smut in Barley and the Surface-borne Smuts (Covered and False Loose Smuts)
Purpose
To evaluate germplasm and advanced lines of barley for reaction to true loose smut and the surface borne smuts and to incorporate the best resistance available into potential new cultivars.
Procedure
New cereal varieties require increased levels of disease resistance to meet the requirements for registration in the future. This program is aimed at meeting these requirements:
a. To identify breeding lines which have resistance to the prevalent pathotypes of the surface-borne smuts and to true loose smut.
b. To identify the genes which impart resistance and to incorporate these genes into new cultivars of six-row and two-row barleys for malting and feed.
Reason for project and impact
Smuts of cereal crops reduce yield and quality. Disease resistance standards for registration of new varieties are increasing. Smut resistance will reduce the need for seed treatment and increase yield and crop quality of Alberta barley.
Summary of results
Large numbers of lines are being screened annually by use of a Field Inoculation procedure. Specific attention is being given to 2-row malting lines and hulless types.
In 2005, approximately 666 barley breeding lines were inoculated with loose smut using an airbrush inoculation technique. Inoculated plant material was grown in the growth room facilities at AAFRD, Lacombe and screened for resistance to loose smut.
In 2005, approximately 283 barley lines, including checks, were inoculated with covered smut using a vacuum inoculation technique. Material was then planted in the field and screened for resistance to covered smut during the summer.
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Surveying Barley Diseases in Alberta
Purpose
To assess and evaluate the prevalence and level of the various barley diseases in central Alberta. To identify and monitor the appearance of new or more prevalent diseases that may be affecting Alberta barley crops. To assess the impact of various cropping practices on barley leaf diseases.
Reason for project and impact
To provide sustainable management of leaf diseases, barley producers, pathologists, agronomists, and breeders need an ongoing and clear indication of the changing disease situation in western Canada. Changes in pathogen virulence and prevalence will have a large impact on the management strategies used by farmers and the direction breeding programs take with regard to the development and utilization of disease resistance.
Results from ongoing barley disease surveys will be used to:
- Establish and demonstrate the importance and impact of barley leaf and root diseases in Alberta.
- Illustrate the importance of resistance for disease management.
- Identify and monitor the appearance or increased prevalence of new or changed barley pathogens.
- Assess the impact of changing cropping practices on barley disease levels.
Summary of results
A survey of diseases of barley and wheat was conducted on July 27-29, 2005 in central Alberta. Growers were contacted for permission to evaluate their fields, which were traversed in an inverted V, with visual analysis of 5 plants taking place at 3 locations. Leaf diseases were scored on a 0-9 scale, with a 4 rating equal to one percent of leaf area diseased (PLAD) on the upper leaf canopy, 5-10 PLAD on the middle canopy and 10-25 PLAD on the lower-canopy. Common root rot (CRR) was assessed on sub-crown internodes using a 0-4 scale where 1=trace and 4=severe. Other diseases were rated as a percent of the plants affected. After the survey was completed, a representative sub-sample of the diseased material collected was cultured in the laboratory for pathogen identification.
General growing conditions in central Alberta were better in 2005 than they had been for some years. A dry May was followed by a cool damp June and a warm showery July. Twenty-two barley fields were examined, only 3 of which were 6-row barley. Barley leaf disease levels were similar to 2004, with scald more common in the northern half of the region and net blotch more common in the south. Barley leaf spots, which were either the spot form of net blotch alone or in combination with Alternaria and Cladosporium species, were also more severe in the south than in the north. Septoria/Stagnospora leaf blotch levels in the 3 fields of wheat examined were similar to 2004. Common root rot of barley occurred at slightly higher ratings than in 2004, while common root rot of wheat ratings were lower than in 2004. The latter was probably related to the intermediate reaction rating of Superb, which was the cultivar in 2 of the 3 fields examined. Loose and covered smuts of cereals were rarely encountered. Stripe rust was only noted in 2 wheat fields at trace levels at this early stage. Subsequent to this survey, stripe rust was noted at very high levels on both wheat and barley in central Alberta. This disease has become more prevalent in central Alberta over the past few years and is causing concern among growers of both wheat and barley.
Fusarium head blight survey in wheat - 2005
During August 2005, cooperative surveys for the presence of fusarium head blight (FHB) in 41 wheat fields in the province were conducted by Agriculture and Agri-Food Canada (AAFC) and staff from the Battle River Research Group, Chinook Applied Research Association, Gateway Research Organization, and North Peace Applied Research Group.
The survey covered an area from the Peace River region to the Oyen area of southern Alberta. In 2005, 21 of the 41 fields had symptoms with average incidence levels of 1.3%, while individual fields ranged from 0.3 to 4.7%. Five of the 11 fields surveyed in the Peace River region had FHB symptoms with incidence levels that ranged from 1.3 to 4.7%, with an average of 2.8%. In central Alberta and the Oyen area, 53% of the fields had FHB symptoms with an average incidence of 0.9%, with a range of 0.3 to 3.0%.
The main Fusarium spp. recovered from symptoms of FHB in central Alberta/Oyen and the Peace River regions was F. avenaceum, with the number of heads per field (out of 300) affected by this pathogen ranging from 1 to 2 heads in 10 of the 21 affected fields. No Fusarium graminearum was detected from heads exhibiting suspected symptoms. F. culmorum was the sole causal agent in 1 of the 5 affected fields from the Peace River region and was recovered from 1 head.
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Barley Variety Resistance to Scald and Net Blotch
Purpose
To determine scald and net blotch reactions of barley cultivars across western Canada.
To evaluate potential sources of scald and net blotch resistance. Barley cultivars and germplasm with resistance that is effective against the most prevalent pathotypes can then be used for sources of resistance by breeding programs.
Procedure
Barley cultivars were grown in hill plots across Alberta and other provinces to evaluate scald and net blotch reactions.
Reason for project and impact
Scald of barley is prevalent in central Alberta and has caused considerable yield and quality losses in this region. Rapid changes in scald races have rendered some cultivar resistance ineffective. Net blotch is widespread in western Canada and sources of resistance are needed for breeding high levels of resistance. The present project primarily evaluated scald resistance at multiple locations and seasons in the hope of finding durable resistance that is effective against the most prevalent pathotypes. Cultivar resistance to leaf diseases like scald and net blotch can be improved by incorporating the sources of resistance determined as part of the current study.
Summary of results
Barley differentials possessing major scald resistance genes were resistant at all sites and seasons. Resistance in a few commercial cultivars such as AC Stacey, CDC Dolly, Kasota, Mahigan and Seebe held up at most sites with the majority of cultivars being intermediate to moderately susceptible. Differentiation of scald reactions provided information on the status of scald resistance in existing cultivars and sources for breeding resistance. Scald reaction of the commercial cultivars was significantly different among sites and seasons, suggesting the presence of scald races variable in virulence among locations.
In 2004, net blotch development due to Pyrenophora teres was satisfactory at Melfort, SK with an average rating of 2.4 on a 0-9 scale, with a minimum 0 and maximum of 8.0. At the Brandon, MB screening site, the average rating was 2.8, with a minimum of 1.0 and maximum of 8.3. At Charlottetown, PEI, significant powdery mildew developed and no net blotch ratings were taken. At Lacombe, the overall average rating was 1.3, with a minimum of 0 and a maximum of 7.0. Net blotch isolations have been taken from sampled leaf material and have been placed in cold storage for subsequent growth chamber/greenhouse inoculations.
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Barley Seeding Date in Relation to Foliar Disease
Purpose
To study seeding date of barley in relation to severity of scald caused by Rhynchosporium secalis and net blotch caused by Pyrenophora teres.
Procedure
The interaction of the two diseases on barley was evaluated in yield trials, each seeded in two dates in a growing season. These trials were carried out at Lacombe in 2001 and at Stettler in 2001, 2003 and 2004. Plot entries consisting of commercial cultivars and breeding lines with varying levels of resistance and susceptibility were naturally infected by scald and net blotch. Disease assessment was made at the soft dough stage of barley using a 0 - 9 scale. Difference in disease severity between two seeding dates was compared using Wilcoxon rank sum test.
Reason for project and impact
The two foliar diseases are prevalent in Alberta and have been found to infect barley in the same field and on the same plant, causing substantial yield and quality losses. Information on the interaction of the two diseases on barley cultivar will be useful in inoculum production, screening for resistance and disease management.
Summary of results
Disease assessments were made from all tests except for the 2004 season where unfavorable conditions hindered diseases from developing and thus, excluded data collection. Higher scald severity was observed on susceptible cultivars in early seeded plots in comparison to those in late seeded plots of all five trials. Similar levels of net blotch severity were found for both seeding dates. There was a weakly negative correlation in disease severity between scald and net blotch. Scald development in early seeding plots will facilitate screening for resistance. For disease management, however, early seeding of scald susceptible cultivars should be avoided in previously scald-infested fields, but the time of seeding will not significantly affect net blotch development.
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Barley Resistance to Fusarium Head Blight
Purpose
Investigate in vitro techniques for screening barley resistant to FHB and study resistance mechanism to FHB and DON accumulation.
Procedure
A series of experiments was carried out to investigate in vitro techniques for the identification of barley resistant/tolerant cultivars or germplasm to FHB. These experiments were determining pathogenicity/virulence of Fusarium graminearum and F. culmorum isolates, screening for resistance/tolerance using detached leaf method, screening for resistance/tolerance using PDA/ground leaf mixture and PDA/grain mixture method and screening barley coleptile of resistant or susceptible genotypes against deoxynivalenol (DON) mycotoxin.
Reason for project and impact
Fusarium head blight incited by F. graminearum has caused considerable quality and yield losses in wheat and barley in the eastern Prairie region of western Canada. New laboratory screening techniques are needed in Alberta where FHB has not been extensively present in the field but sources of resistance/tolerance are required for the development of resistant/tolerant cultivars to prevent FHB epidemics from occurring.
Summary of results
In vitro techniques using detached-leaf method and leaf/grain mixture method have identified resistant Chevron and Penco/Chevron and susceptible AC Lacombe. These results have been consistent with their field reactions to FHB. Ranking of other genotypes based on in vitro experiments was generally in agreement with field rating. However, inconsistent ranking was observed for Stander (S) and CI4196 (R). Some susceptible genotypes appeared to show more DON production in ground grain and detached leaves than resistance/tolerance ones. Antifungal protein analysis indicated that there was slight difference in protein profiles between resistant and susceptible genotypes. Mass spectrometer will be used to identify the proteins from barley genotypes. DON and protein analyses will be repeated using different barley populations.
An initial analysis by 1D and 2D electrophoresis of antifungal proteins present in resistant barley varieties has been completed. We are currently analyzing constitutively express proteins in seed samples utilizing the expertise of the protein laboratory of Dr. A. Murray at AAFC Lacombe.