Progress 10/01/12 to 09/30/13
Outputs
Progress Report Objectives (from AD-416): 1. Evaluate potential biologically active control measures in controlled conditions and the field. 2. Monitor the location-specific variation in scab resistance of potato breeding material and newly released cultivars by field testing (national trials). Approach (from AD-416): Potato seed pieces of 3 popular but scab-susceptible varieties (Yukon Gold, Ranger Russet and Atlantic) will be treated with several individual non-pathogenic isolates of Streptomyces, and planted in Pennsylvania and Michigan fields with high common scab pressure. Treatments will be planted in 4 replicates in a randomized block design, and evaluated at harvest for incidence and severity of common scab. Field test varieties for scab resistance in multiple locations. A total of 20 newly-released potato cultivars and advanced breeding selections plus four popular cultivars as checks (Atlantic, Ranger Russet, Russet Burbank and Superior) will be tested in common scab nurseries in 4 locations, embodying a range of environmental conditions and different pathogen populations. Locations are in Aberdeen, ID, Becker, MN, E. Lansing, MI and University Park, PA. A randomized complete block with three replications of 4 hills will be planted for each clone. At harvest, each tuber will be rated for percent surface area covered with lesions and type of lesion. Data from cooperating sites will be analyzed. The resulting comparison and ranking of susceptibility to predominant Streptomyces isolates will be made available to growers to help them select the most scab-resistant cultivars for their region. Potato common scab is one of the most important potato diseases in the upper Midwest and northeastern United States, because it seriously reduces potato marketability, in both fresh-market sales and in chip and French fry processing. There are no effective chemical or cultural controls for common scab. The most effective control is use of potato varieties resistant to the disease, and potato breeders routinely test their newly developed lines in field trials to establish levels of susceptibility or resistance to the disease. We received notice that the project was funded too late in the spring of 2012 (late May) to repeat the previous 2 years field biocontrol experiments, but we have submitted for publication the results of two years� repetition of the experiment, in which we observed a general decrease in common scab by the biocontrol strains. Responses varied by potato variety, location and year, but some variety-biocontrol strain combinations could be useful for reducing common scab severity. Twenty-four potato varieties selected by potato breeders from 6 breeding programs in the US were tested for common scab in 4 field locations (one field each in Pennsylvania, Michigan, Minnesota, and Idaho). The 4 sites differ in soil and environmental conditions and in the Streptomyces bacteria responsible for the disease. Statistical analysis of the data from 3 locations is ongoing, but quick comparisons of the tested potato breeding lines with resistant and susceptible standard check varieties show that some breeders� selections are more scab-resistant than the susceptible check varieties in all locations. The final results of field-testing potato varieties for their common scab resistance will be used by potato growers to choose the most common-scab resistant varieties for their areas, and will be made available on our USDA website. Some results of common scab field and greenhouse tests are now posted at http://www.ars.usda.gov/pandp/docs.htm?docid=22336.
Impacts
(N/A)
Publications
|
Progress 10/01/11 to 09/30/12
Outputs
Progress Report Objectives (from AD-416): 1. Evaluate potential biologically active control measures in controlled conditions and the field. 2. Monitor the location-specific variation in scab resistance of potato breeding material and newly released cultivars by field testing (national trials). Approach (from AD-416): Potato seed pieces of 3 popular but scab-susceptible varieties (Yukon Gold, Ranger Russet and Atlantic) will be treated with several individual non-pathogenic isolates of Streptomyces, and planted in Pennsylvania and Michigan fields with high common scab pressure. Treatments will be planted in 4 replicates in a randomized block design, and evaluated at harvest for incidence and severity of common scab. Field test varieties for scab resistance in multiple locations. A total of 20 newly-released potato cultivars and advanced breeding selections plus four popular cultivars as checks (Atlantic, Ranger Russet, Russet Burbank and Superior) will be tested in common scab nurseries in 4 locations, embodying a range of environmental conditions and different pathogen populations. Locations are in Aberdeen, ID, Becker, MN, E. Lansing, MI and University Park, PA. A randomized complete block with three replications of 4 hills will be planted for each clone. At harvest, each tuber will be rated for percent surface area covered with lesions and type of lesion. Data from cooperating sites will be analyzed. The resulting comparison and ranking of susceptibility to predominant Streptomyces isolates will be made available to growers to help them select the most scab-resistant cultivars for their region. Potato common scab is one of the most important potato diseases in the upper Midwest and northeastern United States, because it seriously reduces potato marketability, in both fresh-market sales and in chip and French fry processing. There are no effective chemical or cultural controls for common scab. The most effective control is use of potato varieties resistant to the disease, and potato breeders routinely test their newly developed lines in field trials to establish levels of susceptibility or resistance to the disease. We were unable to implement a 3rd year of field-testing biocontrol strains in 2011(Objective 1). We did monitor the location-specific variation in scab resistance of potato breeding material and newly released cultivars by field testing (national trials). We were able to test 27 potato varieties selected by potato breeders from 6 breeding programs in the U.S. for common scab in 4 field locations (one field each in Pennsylvania, Michigan, Minnesota, and Idaho) . The 4 sites differ in soil and environmental conditions and in the Streptomyces bacteria responsible for the disease. Statistical analysis of the data from 3 locations is ongoing, but quick comparisons of the tested potato breeding lines with resistant and susceptible standard check varieties show that breeders� selections are more scab-resistant than the susceptible check varieties in all locations. Data for the field in Michigan were lost. The final results of these field tests will be made available on our USDA Web site; some of the results of common scab field and greenhouse tests are posted at http://www.ars.usda. gov/pandp/docs.htm?docid=22336.
Impacts
(N/A)
Publications
|
Progress 10/01/10 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) 1. Evaluate potential biologically active control measures in controlled conditions and the field. 2. Monitor the location-specific variation in scab resistance of potato breeding material and newly released cultivars by field testing (national trials). Approach (from AD-416) Potato seed pieces of 3 popular but scab-susceptible varieties (Yukon Gold, Ranger Russet and Atlantic) will be treated with several individual non-pathogenic isolates of Streptomyces, and planted in Pennsylvania and Michigan fields with high common scab pressure. Treatments will be planted in 4 replicates in a randomized block design, and evaluated at harvest for incidence and severity of common scab. Field test varieties for scab resistance in multiple locations. A total of 20 newly-released potato cultivars and advanced breeding selections plus four popular cultivars as checks (Atlantic, Ranger Russet, Russet Burbank and Superior) will be tested in common scab nurseries in 4 locations, embodying a range of environmental conditions and different pathogen populations. Locations are in Aberdeen, ID, Becker, MN, E. Lansing, MI and University Park, PA. A randomized complete block with three replications of 4 hills will be planted for each clone. At harvest, each tuber will be rated for percent surface area covered with lesions and type of lesion. Data from cooperating sites will be analyzed. The resulting comparison and ranking of susceptibility to predominant Streptomyces isolates will be made available to growers to help them select the most scab-resistant cultivars for their region. Potato common scab seriously reduces potato marketability, especially in the upper Midwest and northeastern regions of the U.S., and there are no effective chemical controls for the disease. We examined the impact on common scab disease incidence and severity in potato varieties planted in fields with high disease pressure when non-disease-causing (biocontrol) strains of bacteria were added at the time of planting. In Michigan, the proportion of tubers with no scab was increased and the severity of the scab present was reduced by treatment with at least one of the three biocontrol strains in three potato varieties, though results were modest. The results suggest that biocontrol strains could offer a new method for reducing common scab. The most effective control for potato common scab is the use of potato varieties resistant to the disease, and potato breeders routinely test their newly developed lines in field trials to establish levels of susceptibility or resistance to the disease. In 2010, 22 potato varieties selected by potato breeders from 6 breeding programs in the U.S. were tested for common scab in 4 field locations which differ in soil and environmental conditions and in the bacteria responsible for the disease. Statistical analysis of the data from the tests is ongoing, but quick comparison of the tested potato breeding lines with resistant and susceptible standard check varieties shows that breeders selections are more scab-resistant than the susceptible varieties in all locations. Common scab is one of the most important potato diseases in the upper Midwest and northeastern United States, and the results of field-testing common scab resistance will be used to by potato growers to choose common- scab resistant varieties. Progress by Michigan State collaborators was monitored by regular telephone calls, exchange of e-mails, and receipt of a preliminary written report containing experimental results.
Impacts
(N/A)
Publications
|
Progress 10/01/09 to 09/30/10
Outputs
Progress Report Objectives (from AD-416) 1. Evaluate potential biologically active control measures in controlled conditions and the field. 2. Monitor the location-specific variation in scab resistance of potato breeding material and newly released cultivars by field testing (national trials). Approach (from AD-416) Potato seed pieces of 3 popular but scab-susceptible varieties (Yukon Gold, Ranger Russet and Atlantic) will be treated with several individual non-pathogenic isolates of Streptomyces, and planted in Pennsylvania and Michigan fields with high common scab pressure. Treatments will be planted in 4 replicates in a randomized block design, and evaluated at harvest for incidence and severity of common scab. Field test varieties for scab resistance in multiple locations. A total of 20 newly-released potato cultivars and advanced breeding selections plus four popular cultivars as checks (Atlantic, Ranger Russet, Russet Burbank and Superior) will be tested in common scab nurseries in 4 locations, embodying a range of environmental conditions and different pathogen populations. Locations are in Aberdeen, ID, Becker, MN, E. Lansing, MI and University Park, PA. A randomized complete block with three replications of 4 hills will be planted for each clone. At harvest, each tuber will be rated for percent surface area covered with lesions and type of lesion. Data from cooperating sites will be analyzed. The resulting comparison and ranking of susceptibility to predominant Streptomyces isolates will be made available to growers to help them select the most scab-resistant cultivars for their region. No reliable methods of controlling common scab are currently available. Research was conducted in summer 2009 to investigate whether several non- pathogenic strains of Streptomyces that were originally isolated from potatoes might work to counter-act pathogenic Streptomyces strains that cause potato common scab. Five potential biocontrol strains were tested in triplicate hills of three potato cultivars that are highly susceptible to common scab were planted in common scab nurseries (fields with high natural common scab disease pressure) in Michigan and Pennsylvania. All 5 strains decreased the severity of common scab in at least one of the three potato cultivars in Michigan, where natural common scab disease pressure was low. Four of the 5 strains decreased common scab severity on at least one cultivar in Pennsylvania, where the natural disease pressure was very high. These tests are being repeated in the summer of 2010. The best method of limiting common scab damage to potatoes would be the use of resistant cultivars. To identify potato lines with stable resistance to common scab and to determine the importance of genotype x environment interactions on the expression of scab resistance, we conducted field tests at four locations that have different environmental conditions and pathogen populations. Four standard check cultivars and 21 cultivars and breeding lines were tested in Aberdeen, ID, Becker, MN, E. Lansing, MI, and University Park, PA. Data from the 2009 locations are being analyzed, and 20 new varieties, together with check cultivars, are being tested in the same four locations in the 2010 summer field season. Comparisons and common scab susceptibility rankings will be made available to growers to help them select the most scab-resistant cultivars for their region. The impact of this research is that it provides much-needed new information on controlling potato common scab. A new biocontrol method of controlling common scab disease is being evaluated at two locations, and 20 potato cultivars or breeding lines are being evaluated for common scab resistance in multiple locations each year. Progress was monitored by regular telephone calls, exchange of e-mails, and receipt of a preliminary written report containing experimental results.
Impacts
(N/A)
Publications
|
|