Progress 10/01/08 to 09/30/11
Outputs
OUTPUTS: Obj. 1) Multiple attempts to inoculate leaf buds of lowbush blueberry plants in the laboratory were unsuccessful due to low concentrations of ascospores. Preliminary data indicated that the fungus extensively colonizes the vascular system of the leaves before symptoms develop. Obj. 2) Three EST primers were chosen for their ability to differentiate among lowbush blueberry clones. To determine if there is variation of EST profiles within a clone, 19 stems from one clone and 4 or 5 stems from 3 other clones were profiled and found to vary among stems within a clone possibly due to variation in DNA purity. Variation was also found among five clones from one field. A MS student is completing work on the population genetics of Mvc from conventional and organic fields and unmanaged areas. Obj. 3) Fungicide efficacy trials were used to determine the importance of specific leaf spot diseases by determining the effect of controlling the disease on yield compared to untreated controls. In 2008 in two prune fields, a fungicide trial to control powdery mildew found the percentage of leaves with the disease ranged from 8 to 18%, but there was no significant difference between the fungicide treatments and controls. In 2011, there was a high prevalence of powdery mildew which appeared to cause leaf loss in September and was negatively correlated to yield in crop fields. Significant control of leaf drop due to leaf rust with fungicides (27% to 34% compared to untreated controls of 52%) in in prune fields had no significant effect on yield in the following crop year. Trials to determine the efficacy of fungicide and fertilizer treatments for control of Septoria leaf spot were conducted in crop and prune fields in multiple years. The percentage of dropped leaves was significantly decreased with one fungicide (4 to 12%) compared to the controls (10 to 22%), and in one field, also produced a significantly higher yield than the control. Fungicide treatments to prune fields in 2008 did not have a significant effect on leaf drop in 2008 or yield in 2009. In 2009, some fungicides significantly decreased this disease (6 to 8%) compared to the controls (11.5 to 21%), but had no effect on yield. In 2010, there were good conditions for Septoria disease with wet conditions during bloom and very dry conditions in July and August. None of the fungicide treatments affected leaf drop compared to the controls (30 to 38%). Septoria leaf spot does appear to be a disease that affects yield and whose control in the crop year will benefit growers. Valdensinia leaf spot was found in Maine in the summer of 2009 in 12 commercial lowbush fields and 4 plantings of lowbush blueberry and 2 highbush blueberry plantings in backyards. In 2010, two and, in 2011, 3 additional fields were found to have the disease. Burning of diseased areas to eliminate all leaf litter was effective at eradicating the disease from some fields. Untreated fields still had the disease and the severity of Valdensinia leaf spot ranged from only the lower leaves dropping off with leaf spots on surviving leaves to complete leaf loss on heavily infected plants. PARTICIPANTS: S.L. Annis (principal investigator) coordinated all experiments in the laboratory and field, wrote all publications, conducted all presentations to growers or other groups. Kristen McGovern is a research associate paid from grants who has had training in disease identification, and statistical analysis due to this project. Russell Clark (Sept. 2009 to Aug. 2010), Rafael Garcia (February 2010 to Sept. 2011), Lauren McPherson (Sept. 2010 to Sept. 2011), and Gregory Melcher (May 2011 to Sept. 2011) are undergraduate students who were trained and worked during the school year and the summer on isolating and maintaining fungal cultures, extracting DNA, and collecting field data. Ashley Thompson is a Masters graduate student who started in Sept. 2009 and has been trained on fungal maintenance, field work and manipulation of fungal DNA. Blueberry growers have been trained in the Monilinia disease cycle and how to effectively control mummy berry blight using the mummy berry forecast system and how to identify and control various blueberry diseases including Valdensinia leaf spot. Partners to this project include the Wild Blueberry Commission of Maine and the wild blueberry commercial growers of Oxford Foods, Cherryfield, ME, Wyman's Deblois, ME, Allen's Blueberries, Ellsworth, ME, and Cary Nash Blueberries, Union, ME. Collaborators at University of Maine include D. Yarborough, F.A. Drummond, A. Bushway, M. Camire, V. Wu, E. Mallory, J. Smagula, G. Criner, K. McGovern, and personnel at the Blueberry Hill Farm, Jonesboro, ME. Out of state collaborators include S. Schloemann Mass. Cooperative Extension, B. Grube NH Cooperative Extension, P. Hildebrand, Agriculture and Agri-Food Canada, Kentville, NS, Canada. TARGET AUDIENCES: The target audience for information produced by this project is the commercial lowbush blueberry growers and field managers of Maine, NH and Mass. and the general public living near blueberry fields, growing patches of blueberries, or interested in blueberries. Information to growers on the disease cycle of mummy berry disease, and other diseases including Valdensinia leaf spot and methods to use for control were presented at Growers meetings in three locations around the state in March and at twilight meetings in three locatios around the state in April and May of 2009, 2010 and 2011. Information on using the Mummy berry forcasting method and results from field experiments was also presented to growers at the Wild Blueberry field day, mid July each year and provided on the www.wildblueberries.maine.edu website and on the blog associated with this website. Presentations of results were made at the Wild Blueberry Researcher and Extension Workers meeting in 2009, 2010 and 2011 and at the North American Blueberry research and extension workers meeting in 2010. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Monilinia vaccinii-corymbosi (Mvc) causes mummy berry disease in all blueberry species. The initial leaf and bud infection is the critical stage that can significantly affect yield in lowbush blueberries. Determining how the fungus infects the leaves provides information useful for identifying characteristics in lowbush and other blueberries that are involved in resistance to the initial infection by Mvc. Preliminary data suggested that the fungus extensively colonizes the vascular system of the leaves before symptoms develop, and further research into preliminary infection stages is continuing. Lowbush blueberries have been proposed to have a high degree of genetic variability, and knowledge of the genetics of clones of lowbush blueberries varying in susceptibility to Mvc will aid in breeding of blueberries for resistance and provide basic knowledge for future studies in disease resistance processes. Preliminary data indicates that there is variation among clones in a field, but more clones of varying disease resistance need to be tested. Ongoing research is also examining the population genetics of Mvc isolates from fields managed by fungicide applications, organically managed fields, and unmanaged areas. Leaf spots that cause early leaf drop are of great concern for growers since leaf drop may decrease flower bud production and yield. For lowbush blueberry growers in Maine, a high priority is the determination of the effects of leaf spot diseases on yield and the development of control strategies for these damaging diseases. Fungicide efficacy trials were used to determine the effect of controlling specific diseases on yield. Powdery mildew and leaf rust occur mainly on plants in the prune year and while causing leaf drop do not significantly affect yield in the next year's crop. Septoria leaf spot affects both prune and crop fields, but only control of this disease in crop fields had an effect upon yield. Previously, fungicides were found to significantly decrease Septoria leaf spot severity and increase yield. In 2010, none of the fungicides tested significantly decreased disease presumable from the high disease pressure due to good weather conditions for Septoria infection. From 2009, Valdensinia leaf spot, which can cause complete defoliation of heavily infected plants, has been found in Maine in 17 commercial blueberry fields and 6 lowbush or highbush blueberry plantings. Grower meetings since 2009 have educated growers about the differences between Septoria, "false Valdensinia" and Valdensinia leaf spots and their control measures. There has been an increase in the awareness and knowledge of Valdensinia leaf spot throughout the blueberry growing areas of the state. Due to the identification of Valdensinia leaf spot, growers became more aware of the disease and its effects on lowbush blueberry. Researchers and some blueberry growers are enacting methods to limit the spread of this disease by screening for contamination of equipment and personnel before moving between fields.
Publications
- Drummond, F.A., J. Smagula, D. Yarborough, and S. Annis. 2011. Organic wild blueberry research and extension in Maine, International Journal of Fruit Science, accepted.
- Drummond, F., S. Annis, J. M. Smagula and D.E. Yarborough. 2009. Organic Production of Wild Blueberries. I. Insects and Disease. Acta Hort. 810: 275-286.
- Smagula, J.M., D.E. Yarborough, F.A. Drummond, and S. Annis. 2009. Organic Production of Wild Blueberries II. Fertility and Weed Management. . Acta Hort. 810: 673-684.
- Yarborough, D.E., J.M. Smagula, F.A. Drummond, and S. Annis. 2009. Organic Production of Wild Blueberries III. Fruit Quality. Acta Hort. 810: 847-852.
- S. Annis. 2009. Valdensinia leaf spot, NEW Disease in Maine Blueberry Fields http://wildblueberries.maine.edu/PDF/Disease/Valdensinia0809.pdf
- S. Annis. 2009. Sanitation to Protect Fields from Valdensinia leaf drop Disease http://wildblueberries.maine.edu/factsheets/Disease/valdensiniasanita tionmethods.html
- S. Annis. 2009. Forecasting Mummyberry Fungus Infection 2009 http://wildblueberries.maine.edu/PDF/Disease/mummyberry-forecasting-h andout.pdf
- S. Annis. 2009. Mummy berry disease forecasting method, presentation put up on the web http://wildblueberries.maine.edu/Mummyberry/mummyberryforecastingmeth od.pdf
- S. Annis. 2009. Valdensinia leaf spot on Wild Blueberries, presentation published on web http://wildblueberries.maine.edu/PDF/Disease/Valdensinia0809.pdf
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Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: Objective 1. Attempts to inoculate leaf buds of lowbush blueberry plants in the laboratory were unsuccessful due to low concentrations of ascospores. Low numbers of ascospores were produced by overwintered pseudosclerotia in 2010. Preliminary data from previously infected tissue indicates that the fungus extensively colonizes the vascular system. Objective 2. This objective is incomplete but research is ongoing. Three EST primers were used to determine if there is variation of EST profiles within a clone. 19 stems from one clone and 4 or 5 stems from 3 other clones were profiled and found to vary among stems within a clone possibly due to variation in DNA purity. Different methods of DNA clean-up are being tested. Variation was also found among five clones from one field, but this data will be re-evaluated once the level of variation within a clone is determined. A Masters graduate student started in Sept. 2009 and is working on the population genetics of Monilinia vaccinii-corymbosi from conventional and organic fields and unmanaged areas. We have collected isolates from 3 fields of each management type and are in the process of testing microsatellite primers for use in determining the genetic diversity of these fungal populations. Objective 3. Trials to determine the efficacy of fungicide treatments for control of Septoria leaf spot were conducted in crop fields in 2010. There were good conditions for Septoria disease with wet conditions during bloom and very dry conditions in July and August. None of the fungicide treatments affected leaf drop compared to the controls (30 to 38%). Septoria leaf spot does appear to be a disease that affects yield and whose control in the crop year will benefit growers. Valdensinia leaf spot was found in 12 commercial fields, (8 prune and 4 crop) and 4 plantings of lowbush blueberry and 2 highbush blueberry plantings in backyards in 2009. In 2010, two additional commercial fields were found to have the diseases. Growers who performed "hard burns" of their fields were able to eradicate the disease. Untreated fields still had the disease and the severity of Valdensinia leaf spot ranged from only the lower leaves dropping off with leaf spots on surviving leaves to complete leaf loss on heavily infected plants. There was also high prevalence of a large brown leaf spot, "false Valdensinia" found in Maine blueberry fields. Information on mummy berry disease and leaf spots was presented at growers meetings in March (30 to 60 growers at each) and at twilight meetings (10 to 30 growers at each) in April, May and June around Maine. Results of studies were presented to growers and other researchers at Blueberry Hill Farm Field day in July (about 200 people attended), and the NABREW and WildBREW meetings for blueberry researchers. PARTICIPANTS: S.L. Annis (principal investigator) coordinated all experiments in the laboratory and field, wrote all publications, conducted all presentations to growers or other groups. Kristen McGovern is a research associate paid from grants who has had training in disease identification, and statistical analysis due to this project. Russell Clark (Sept. 2009 to Aug. 2010) and Rafael Garcia (February 2001 to Dec. 2010) are undergraduate students who were trained and worked during the school year and the summer on isolating and maintaining fungal cultures, extracting DNA, and collecting field data. Ashley Thompson is a Masters graduate student who started in Sept. 2009 and has been trained on fungal maintenance, field work and manipulation of fungal DNA. Blueberry growers have been trained in the Monilinia disease cycle and how to effectively control mummy berry blight using the mummy berry forecast system and how to identify and control various blueberry diseases including Valdensinia leaf spot. Partners to this project include the Wild Blueberry Commission of Maine and the wild blueberry commercial growers of Oxford Foods, Cherryfield, ME, Wyman's Deblois, ME, Allen's Blueberries, Ellsworth, ME, and Cary Nash Blueberries, Union, ME. Collaborators at University of Maine include D. Yarborough, F.A. Drummond, A. Bushway, M. Camire, V. Wu, E. Mallory, J. Smagula, G. Criner, K. McGovern, and personnel at the Blueberry Hill Farm, Jonesboro, ME. Out of state collaborators include S. Schloemann Mass. Cooperative Extension, B. Grube NH Cooperative Extension, P. Hildebrand, Agriculture and Agri-Food Canada, Kentville, NS, Canada. TARGET AUDIENCES: The target audience for information produced by this project is the commercial lowbush blueberry growers and field managers of Maine, NH and Mass. and the general public living near blueberry fields, growing patches of blueberries, or interested in blueberries. Information to growers on the disease cycle of mummy berry disease, and other diseases including Valdensinia leaf spot and methods to use for control were presented at Growers meetings around the state on March 17, 18 and 20th 2010 and at twilight meetings on April 27, 28, 29, May 25, 26 and 27th, 2010. Information on using the Mummy berry forcasting method and results from field experiments was also presented to growers at the Wild Blueberry field day, July 21st 2010, and provided on the www.wildblueberries.maine.edu website and on the blog associated with this website. Presentations of results on organically acceptable fungicides was presented the North American Blueberry research and extension workers meeting July 26 to 28, 2010 and at the Wild blueberry research and extension workers meeting in Quebec City, Canada, Oct. 21, 2010. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Monilinia vaccinii-corymbosi causes mummy berry disease in all blueberry species. The initial leaf and bud infection is the critical stage that can significantly affect yield in lowbush blueberries, but in rabbiteye and highbush blueberries the number of mummified fruit affects yield. Determining how the fungus infects the leaves provides information useful for identifying characteristics in lowbush and other blueberries that are involved in resistance to the initial infection by M. vaccinii-corymbosi. Preliminary data suggests that the fungus extensively colonizes the vascular system of the leaves before symptoms develop, and further research into preliminary infection stages is continuing. Lowbush blueberries have been proposed to have a high degree of genetic variability, and knowledge of the genetics of clones of lowbush blueberries varying in susceptibility to M. vaccinii-corymbosi will aid in breeding of blueberries for resistance and provide basic knowledge for future studies in disease resistance processes. Preliminary data indicates that there is variation among clones in a field, but more clones of varying disease resistance need to be tested. Ongoing research is examining the population genetics of M. vaccinii-corymbosi using microsatellite markers in conventional and organic fields, and unmanaged areas. Leaf spots that cause early leaf drop are of great concern for growers since leaf drop may decrease flower bud production and yield. For lowbush blueberry growers in Maine, a high priority is the determination of the effects of leaf spot diseases on yield and the development of control strategies for these damaging diseases. Fungicide efficacy trials were used to determine the effect of controlling specific diseases on yield. Powdery mildew and leaf rust occur mainly on plants in the prune year and while causing leaf drop do not significantly affect yield in the next year's crop. Septoria leaf spot affects both prune and crop fields, but only control of this disease in crop fields had an effect upon yield. Previously, fungicides were found to significantly decrease Septoria leaf spot severity and increase yield. In 2010, none of the fungicides tested significantly decreased disease presumable from the high disease pressure due to good weather conditions for Septoria infection. In 2009 and 2010, Valdensinia leaf spot, which can cause complete defoliation of heavily infected plants, was found in Maine in 14 commercial blueberry fields and 6 lowbush or highbush blueberry plantings. Grower meetings in 2010 educated growers about the differences between Septoria, "false Valdensinia" and Valdensinia leaf spots and their control measures. There has been an increase in the awareness and knowledge of Valdensinia leaf spot throughout the blueberry growing areas of the state. Due to the identification of Valdensinia leaf spot, growers became more aware of the disease and its effects on lowbush blueberry. Researchers and some blueberry growers are enacting methods to limit the spread of this disease by screening for contamination of equipment and personnel before moving between fields.
Publications
- McGovern, K., S. Annis and D. Yarborough, 2011 pending. Efficacy of organically acceptable materials for control of mummy berry disease on wild blueberries in Maine. Journal article. Acta Horticulturae
- McGovern, K., S. Annis and D. Yarborough, 2010. Efficacy of organically acceptable materials for control of mummy berry disease on wild blueberries in Maine. Abstract. North American Blueberry Researchers and Extension Workshop, Kalamazoo, MI, July 25-28, 2010.
- Drummond, F.A., J. Smagula, D. Yarborough, and S. Annis, 2010, Organic wild blueberry research and extension in Maine. Abstract. North American Blueberry Researchers and Extension Workshop, Kalamazoo, MI, July 25-28, 2010.
- S. L. Annis, D. Yarborough, K. McGovern , J. D'Appollonio. 2009. Maine Wild Blueberry fungicide evaluation trials 2009-2010. Technical Report. USDA/CREES and Wild Blueberry Commission.
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Objective 1: Examine the infection process of Monilinia vaccinii-corymbosi, the causal agent of mummy berry blight, in lowbush blueberry leaves. Attempts to inoculate leaf buds of lowbush blueberry plants in the laboratory were unsuccessful due to a low concentration of ascospores. Higher numbers of mummy berries were set up to overwinter to harvest for ascospores in spring 2010. The aniline blue staining method was tested and found to work for tracing fungal hyphae in infected leaves. Information to growers on the disease cycle of mummy berry disease and methods to decrease fungicide use for control were presented at Growers meetings around the state on March 18, 19 and 21, 2009 and at twilight meetings on April 28, 29, and 30th and May 26, 27 and 28th. Information on using the Mummy berry forcasting method was provided on the www.wildblueberries.maine.edu website and on the blog associated with this website. A presentation on the mummy berry forecasting method was given on Oct. 29th at the Wildbrew meeting in Bangor, ME. Objective 2) Determine the genetic variability among lowbush blueberry clones differing in susceptibility to infection by Monilinia vaccinii-corymbosi from different areas of Maine. Three EST primers were chosen for their ability to differentiate among lowbush blueberry clones. The EST profiles from one primer for 20 stems per clone for 3 clones in a field are being completed. Analysis of the profiles will determine the number of stems to be fingerprinted per clone in the next round of PCR amplifications. Four microsatellite primers were identified that produced different banding patterns amongst Monilinia vaccinii-corymbosi isolates from one field. Objective 3) Determine which fungi are causing leaf spots that result in early leaf drop in Maine, their effect on yield, and develop control strategies for these fungi. The fungus, Valdensinia heterodoxa, causal agent of Valdensinia leaf spot, was found in Maine in the summer of 2009. Patches of leaf drop caused by this disease were found in 12, 8 prune and 4 crop, commercial lowbush blueberry fields. The disease was also identified in 4 lowbush blueberry stands or plantings and 2 highbush blueberry plantings in backyards. Isolates were collected from infected leaves from infected sites in Maine. These isolates will be used to further study the disease by inoculation trials, DNA fingerprinting and testing of control methods. A presentation on identifying this disease and methods to control its spread were given to growers at the Wild Blueberry field day, July 15th, and then subsequent informal meetings were conducted with groups of growers on July 28, July 29th, July 30th , July 31st,and Aug 4th. Information on identifying and controlling Valdensinia leaf spot disease was also posted on the www.wildblueberries.maine.edu website. PARTICIPANTS: S.L. Annis (principal investigator) coordinated all experiments in the laboratory and field, wrote all publications, conducted all presentations to growers or other groups, except the fungicide results talk at the Wildbrew meeting in October that was presented by K. McGovern. Kristen McGovern is a research associate paid from grants who has had training in disease identification, and statistical analysis due to this project. Wayne Sowers is an undergraduate student who has been trained and has worked during the school year and the summer on extracting DNA, DNA fingerprinting stems of lowbush blueberry, and collecting field data. Russell Clark is an undergraduate student who has been trained and then worked during the school year on culturing and maintaining Monilinia vaccinii-corymbosi isolates. Amanda Stevens is an undergraduate student who has been trained and who has worked part of the school year on maintaining fungal cultures and general lab maintenance. Partners to this project include the Wild Blueberry Commission of Maine and the wild blueberry commercial growers of Oxford Foods, Cherryfield, ME and Allen's Blueberries, Ellsworth, ME. Collaborators at University of Maine include D. Yarborough, F.A. Drummond, A. Bushway, M. Camire, V. Wu, E. Mallory, J. Smagula, G. Criner, K. McGovern, and personnel at the Blueberry Hill Farm, Jonesboro, ME. Out of state collaborators include S. Schloemann Mass. Cooperative Extension, B. Grube NH Cooperative Extension, P. Hildebrand, Agriculture and Agri-Food Canada, Kentville, NS, Canada. TARGET AUDIENCES: The target audience for information produced by this project is the commercial lowbush blueberry growers and field managers of Maine, NH and Mass. and the general public living near blueberry fields, growing patches of blueberries, or interested in blueberries. Information to growers on the disease cycle of mummy berry disease and methods to decrease fungicide use for control were presented at Growers meetings around the state on March 18, 19 and 21, 2009 and at twilight meetings on April 28, 29, and 30th and May 26, 27 and 28th. Information on using the Mummy berry forcasting method was provided on the www.wildblueberries.maine.edu website and on the blog associated with this website. A presentation on the mummy berry forecasting method was given on Oct. 29th at the Wildbrew meeting in Bangor, ME. A presentation on identifying Valdnesinia leaf spot disease and methods to control its spread were given to growers at the Wild Blueberry field day, July 15th, and then subsequent informal meetings were conducted with groups of growers and interested public on July 28, July 29th, July 30th , July 31st,and Aug 4th, 2009. Information on identifying and controlling Valdensinia leaf spot disease was also posted on the www.wildblueberries.maine.edu website. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Approximately 80 growers attended the March growers meetings and approximately 50 growers attended the twilight meetings and increased their knowledge about the mummy berry forecasting method, and how to identify and control this disease. An informal poll showed that 6 growers had made mummy berry plots in their fields to track the fungus's progress in the spring. Approximately 80 to 110 blueberry growers and workers attended informal meetings about Valdensinia leaf spot in July and August and obtained information about identifying this disease and methods to eradicate the disease from their fields. The nine lowbush blueberry growers or field managers with Valdensinia leaf spot in their fields, burned the diseased areas after learning that this has a good chance of eradicating the fungus from their fields. In the laboratory, 4 undergraduate students learned and improved their skills in fungi isolation and culture, DNA extraction for fungi and plants and evaluation of disease samples.
Publications
- S. L. Annis, D. Yarborough, J. DAppollonio, K. McGovern. 2009. Maine Wild Blueberry fungicide evaluation trial 2009. Wild Blueberry Commission.
- S.L. Annis and K. McGovern. 2009. Research on Wild Blueberry Diseases for 2009. Wild Blueberry Commission.
- S. Annis 2009. Valdensinia leaf spot: a report on a new disease in Maine. Abstract and Presentation. Wildbrew meeting, Bangor, ME Oct. 29th, 2009
- S.L. Annis, K. McGovern, and D. Yarborough. 2009. Fungicide trials for control of Mummy berry and Septoria leaf spot in Maine. Abstract and Presentation. Wildbrew meeting, Bangor, ME Oct. 29th, 2009
- S.L. Annis. 2009. Valdensinia Leaf Spot Disease. Factsheet http://wildblueberries.maine.edu/factsheets.html#disease
- S.L. Annis. 2009. Sanitation Protocol for Valdensinia leaf drop Disease. Factsheet. http://wildblueberries.maine.edu/factsheets.html#disease
- Drummond, F., S. Annis, J. M. Smagula and D.E. Yarborough. 2009. Organic Production of Wild Blueberries. I. Insects and Disease. Acta Hort. 810: 275-286.
- Smagula, J.M., D.E. Yarborough, F.A. Drummond, and S. Annis. 2009. Organic Production of Wild Blueberries II. Fertility and Weed Management. . Acta Hort. 810: 673-684.
- Yarborough, D.E., J.M. Smagula, F.A. Drummond, and S. Annis. 2009. Organic Production of Wild Blueberries III. Fruit Quality. Acta Hort. 810: 847-852.
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