Progress 10/01/04 to 09/30/09
Outputs
OUTPUTS: Etiology and Epidemiology of Plant Viruses in South Dakota focused on providing diagnosis, evaluation, analysis, and management for plant viruses affecting wheat, soybeans, legumes, and other hosts in South Dakota. Wheat streak mosaic virus (Genus: Tritimovirus; Family: Potyviridae) (WSMV) is the most important viral disease of wheat in South Dakota. This project utilized high pressure inoculation (552 kPa) spray to evaluate winter wheat lines for their reaction to a South Dakota WSMV isolate by inoculation of a split plot (4 rows; 5 m length) using 1:10 (weight:volume) maceration of WSMV-infected Arapaho wheat and 0.02 M potassium phosphate buffer (pH 7.0) with 1% silica carbide added. Plants were inoculated at Feekes stage 2 and were rated for symptom development and severity. Heights and yields were also measured. During the period of this project, 347 winter wheat lines from the AYT-CPT Nurseries and 328 lines from the Northern/Southern Winter Wheat Regional Nurseries were evaluated. The evaluation of these 725 lines contributed to the release of four winter wheat varieties: Alice, Darrell, Expedition, and Wendy. WSMV affects spring wheat in areas where the spatial and temporal separation has been broken by growing spring and winter wheat in close proximity. Twelve lines of spring wheat were evaluated using the same protocol as for winter wheat except for the utilization of eight row split plots. All spring wheat lines tested demonstrated greater than 50% yield loss indicating that spring wheat should be evaluated for WSMV resistance if lines will be recommended for use in close proximity to winter wheat or as fill for areas of winter kill in winter wheat. Bean pod mottle virus (Genus: Comovirus; Family: Comoviridae) (BPMV) is a major viral disease affecting soybeans in South Dakota. A high pressure inoculation method (similar to the protocol used for WSMV) was developed for field evaluation of soybean lines in an eight row split plot. BPMV caused yield losses up to 54%, a loss of approximately one pod per node, and an average of 0.7 seed per pod. BPMV also affected the disease severity, height, and nodes per plant in all soybean lines evaluated. Additionally, it also significantly decreased (P < 0.0075) the percentage of oil in seed from inoculated plants of ten soybean lines. Surveys during 2006-2008 for soybean mosaic virus (Family: Potyviridae; Genus: Potyvirus) (SMV) in South Dakota were conducted. Fifty random samples were collected in a W pattern (1 m intervals) from the soybean fields in each county. Each sample consisted of the upper two fully expanded leaves from every selected soybean plant. Samples were held on ice for transport to freezer storage (-20 C). Frozen leaves were processed to extract sap and assayed for SMV by ELISA. SMV was detected in all counties included in the survey. Surveys for legume viruses and development of materials for the Legume IPM PIPE website were an active output of this project. PARTICIPANTS: Individuals: Marie A. C. Langham served this project as principal investigator and research director. In 2009, Pat Wieland served this project as senior agricultural technician for eight months and was in charge of daily greenhouse care, collecting agronomic traits for field research, and laboratory assays. Tomi Walking Stick served as temporary technician with the same duties for four months. Robert Johnson, Vedbar Khadka, Manasa Sadineni, Adam Johnson-Ahmed, and Ashok Rijal served this project as student research assistants doing laboratory, field, and greenhouse procedures. Partner Organizations: The following provided funding for research projects that contributed to the goals of this project: South Dakota Wheat Commission, South Dakota Soybean Research and Promotion Council, North Central Soybean Research Program, and Legume ipm-PIPE. Collaborators and Contacts: During this period, this project had collaborative relationships with William Berzonsky (Winter Wheat Breeding Project), Karl Glover (Spring Wheat Breeding Project), and the Soybean Breeding Project for evaluation of plant materials. Interaction with the Legume PIPE and its participants also advanced the virus management and education goals of this project. Additionally, interaction and contact between this project and NCERA 200 scientists and other participants advanced the research of this project. Training or Professional Development: This project provided a training webinar on plant viruses for Great Plains diagnosticians, interaction with the undergraduate and graduate teaching program at South Dakota State University, diagnostic assistance the South Dakota State Plant Diagnostic Clinic, and consulting with producers. TARGET AUDIENCES: Target Audiences: Principal target audiences of this project include fellow scientists, industry researchers, extension educators, diagnosticians, producers, and other stakeholders. Presentations and publications for peer scientific groups have been presented at national and regional meetings and in peer publications. South Dakota producers and stakeholders have also been provided presentations. This project contributes to the Legume ipm-PIPE, a nationally available website for legume producers, stakeholders, and scientists. Both electronic and hard copy publications for producers, stakeholders, and the Risk Management Agency have been a part of the Legume PIPE as well as coordination, training and stakeholder meetings. A training webinar on plant viruses was provided for Great Plains diagnosticians. Graduate and undergraduate students were provided opportunities to work with virus infected plants during laboratories concentrating on plant viruses. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Plant viral diseases have a fundamental impact on South Dakota agriculture and stakeholders. Winter wheat demonstrated significant yield losses when infected with wheat streak mosaic virus (Genus: Tritimovirus; Family: Potyviridae) (WSMV). Height, heading dated, and test weight were all significantly impacted by WSMV. Evaluation of winter wheat lines demonstrated variability in the response of wheat lines to WSMV infection. This variability was utilized to produce improved winter wheat varieties. Winter wheat yield loss data provided producers with the information to make informed choices in varietal selections. Additionally, evaluation of spring wheat lines demonstrated that more research on the interaction of overlapping spring and winter wheat crops is needed due to the significant impact on spring wheat yield and growth. Bean pod mottle virus (Genus: Comovirus; Family: Comoviridae) (BPMV) dramatically reduced the yield of soybeans while also impacting their agronomic traits. Reduced growth and reduced branching can promote the development of other pathogens. Early infection by BPMV was demonstrated to cause significantly greater losses in soybean. Soybean mosaic virus (Family: Potyviridae; Genus: Potyvirus) (SMV) was identified in surveys of fifteen South Dakota counties and is now known to have a wide range in Eastern South Dakota. The occurrence of both BPMV and SMV in South Dakota presents a potential additional impact for the producers due to the synergistic reactions found in soybeans when these two viruses occur in double infection. Other soybean and legume viruses that cause potential impacts on these crops were identified for future research.
Publications
- Schwartz, H.F., Langham, M.A.C., Golod, J., Tolin, S. A., LaForest, J., and Cardwell, K.F. 2009. Legume ipmPIPE: The next evolution of web-based interactive tools for disease management and extension outreach. APS Net, Feature Article, May 2009. American Phytopathological Society. http://www.apsnet.org/online/feature/ipmPIPE/.
- Langham, M.A.C., Schwartz, H.F., Tolin, S.A., Sutula, C., Ratcliffe, S., and Cardwell, K.F. 2009. Legume ipmPIPE-A tool for disease management and education in legumes. The Bean Improvement Cooperative, Twelfth Biennial Meeting Program and Abstract Book, Fort Collins, CO. October 25-29, 2009.
- Tolin, S. A., and Langham, M. A. C. 2009. Virus surveillance in beans using tissue blot immunoassay: Three years experience of the Legume ipm-PIPE. The Bean Improvement Cooperative, Twelveth Biennel Meeting Program and Abstract Book, Fort Collins, CO. October 25-29, 2009.
- Tolin, S. A., and Langham, M. A. C. 2009. Aphid-transmitted viruses. Legume ipm-PIPE Pocket Diagnostic Series. Legume ipm-PIPE. USDA Integrated Pest Management-Pest Information Platform for Extension and Education. (Available in hard copy or on http://legume.ipmpipe.org/cgi-bin/sbr/public.cgi).
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Etiology and Epidemiology of Plant Viruses in South Dakota is a varied project with outputs that address the major plant viral diseases in the state. Included in these activities and services is research to ameliorate the impact of these viruses on crop losses in South Dakota. Plant viruses affect SD agriculture through yield losses, delayed maturity, stunting, sterility, reduced flower set, reduced seed/kernel size and number, and seed effects. Bean pod mottle virus (BPMV) (Genus: Comovirus; Family: Comoviridae) is the major virus affecting soybean in South Dakota. One of the research projects during 2008 was to evaluate the performance of five soybean cultivars in field conditions when infected with BPMV. The cultivars included in this study are 1161RR/SCN, 3219R, LD05-16137, SDXR-017-52, and SDXR-020-18. The plots utilized in this study were 8 row split plots with one of the split plots being inoculated with BPMV-infected sap extract (1:10 BPMV-infected Phaseolus vulgaris cv. Provider : 0.02 M Na and K phosphate buffer, pH 7.2) by high pressure inoculation. Data collected for these plots included: Disease severity ratings, Height measurements, Node counts, Seed and pod counts, yield and test weights, ELISA analysis, and Maturity dates and lodging. BPMV and soybean mosaic virus (SMV)(Genus: Potyvirus; Family: Potyviridae) have a synergistic effect when they infect the same soybean plant. Synergistic effects cause greater damage to the host than when the damages caused by either virus alone are combined. It has been shown to cause up to 100% yield loss in infected soybean lines from late maturity groups, such as Hutchinson. However, less is known about damage levels in early maturity groups. Research was designed to explore the effects of dual infection on early maturity groups and to analyze mixed infection as a tool for multiple adversity resistance screening. An advantage of this method if it is applicable for large scale screenings is obtaining information on two viruses simultaneously. Greenhouse plants are inoculated with SMV and BPMV in three sequences, repeated in a completely randomized block pattern. Plants are rated for symptom expression, growth, and virus titer. Wheat streak mosaic virus (WSMV) (Family: Potyviridae; Genus: Tritimovirus) causes the most economically important viral disease affecting winter wheat in South Dakota. Studies have shown that winter wheat losses due to WSMV range from 2.5-5 million bushels annually with greater losses than this occurring in epidemic years. Sixty-three winter wheat lines entered in the AYT-CPT trials were planted in the 2008 WSMV winter wheat evaluation nursery. Winter wheat lines were planted in four row plots in three replications, and half the plot was inoculated using a high-pressure (80 psi) air compressor. Plants were inoculated in the field during October at Feekes stage 2 with a mixture of 1:10 infected plant tissue and potassium phosphate buffer (KPB), pH 7.0, with 1% of silica carbide powder (600 mesh) added. Plants were rated for symptom development and severity. Heights and yields were also measured. PARTICIPANTS: Individuals: Marie A. C. Langham served this project as principal investigator and research director; Pat Wieland served this project as senior agricultural technician and was in charge of daily greenhouse care, collecting agronomic traits for field research, and laboratory assays; Indu Gurun, Khem Phuyal, and Devendra Dahal served this project as student research assistants doing laboratory, field, and greenhouse procedures. Partner Organizations: The following provided funding for research projects that contributed to the goals of this project: South Dakota Wheat Commission, South Dakota Soybean Research and Promotion Council, and North Central Soybean Research Program. Collaborators and Contacts: During this period, this project had collaborative relationships with SDSU Winter Wheat Breeding Project, Karl Glover, and Roy Scott (SDSU, Plant Science) for evaluation of plant materials. Interaction with the Legume PIPE and its participants also advanced the virus management and education goals of this project. Additionally, interaction and contact between this project and NCERA 200 scientists and other participants advanced the research of this project. Training or Professional Development: In 2008, this project provided a training webinar on plant viruses for Great Plains diagnosticians, interaction with the undergraduate and graduate teaching program at South Dakota State University, diagnostic assistance the South Dakota State Plant Diagnostic Clinic, and consulting with producers. TARGET AUDIENCES: Target Audiences: During 2008, the principal target audiences of this project have been producers and extension educators and diagnosticians. A training webinar on plant viruses was provided for Great Plains diagnosticians. Graduate and undergraduate students were provided opportunities to work with virus infected plants during laboratories concentrating on plant viruses. PROJECT MODIFICATIONS: There have been no major changes in this project during 2008.
Impacts
Yield losses due to plant viruses continue to cause heavy impacts on South Dakota agriculture. Bean pod mottle virus (BPMV) (Genus: Comovirus; Family: Comoviridae) continues to be the major virus affecting soybean production in South Dakota. Development of new cultivars that are suitable for South Dakota needs to include assessment of BPMV's impact on the soybean lines. Variability within soybean germplasm tested in BPMV evaluations has shown that improvement of soybean cultivars' response to BPMV is possible and can contribute to cultivar improvement. Field screening provides good methodology for cultivars that are in the later stages of development; however, it limits the number of lines which can be evaluated. Greenhouse screening methods for early generations provides the possibility to increase the numbers of lines which can be evaluated. Utilizing the synergistic properties of BPMV and soybean mosaic virus (SMV) (Genus: Potyvirus; Family: Potyviridae) has the potential to develop into a multiple adversity evaluation technique. Additionally, wheat streak mosaic virus (WSMV) (Family: Potyviridae; Genus: Tritimovirus) is the most important virus affecting wheat in South Dakota. Sixty-eight lines were evaluated in split plot field studies. Evaluations displayed a diversity of genetic reactions that can be used in selecting these lines for future work.
Publications
- Schwartz, H.F., and Langham, M.A.C. (2008). PIPE: Pest information platform for extension and education. Bean Improvement Cooperative Annual Report 51: 4-6.
- Langham, M.A.C., Tolin, S.A., Sutula, C., Schwartz, H., Wisler, G., Karasev, A., Hershman, D., Giesler, L., Golod, J., Ratcliffe, S.T., and Cardwell, K.F. (2008). LegumePIPE: A new tool for disease management in legumes. Bean Improvement Cooperative Annual Report 51:60.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Viruses of concern in South Dakota include not only viruses that have been previously found, such as bean pod mottle virus (BPMV) (Family: Comoviridae; Genus: Comovirus) or wheat streak mosaic virus (WSMV) (Family: Potyviridae; Genus: Tritimovirus), but also, viruses whose epidemic or endemic range expands into South Dakota. During 2006, a survey began in ten counties to determine whether or not soybean mosaic virus (SMV) (Family: Potyviridae; Genus: Potyvirus) was present in South Dakota. Fifty random samples were collected in a W pattern (1 m intervals) from the soybean fields in each county. Each sample consisted of the upper two fully expanded leaves from every selected soybean (Glycine max) plant. Samples were held on ice for transport to freezer storage (-20 C). Frozen leaves were processed to extract sap and assayed for SMV by ELISA during early 2007. SMV was detected in all counties included in the survey with the following average incidence of infected plants for
the county: Bon Homme (11.6%), Brookings (3.6 %), Clark (4.0%), Clay (4.8%), Codington (1.6%), Hutchinson (8.8%), Lincoln (4.8%), Turner (7.2%), Union (4.4%), and Yankton (2.8%). Sample collection for this survey continued during the 2007 growing season with 50 random samples collected from five soybean producers' fields in 15 counties. Counties sampled in 2007 included Bon Homme, Brown, Brookings, Clark, Clay, Codington, Hutchinson, Kingsbury, Lincoln, Minnehaha, Roberts, Spink, Turner, Union, and Yankton. Analysis of 2007 samples is in progress. Effects of WSMV on winter wheat (Triticum aestivum L.) were assessed on wheat lines from the South Dakota winter wheat breeding, crop performance testing, and regional evaluation nurseries. Lines were planted in 4-row plots (5 m length), and half of the plot was inoculated by high pressure (552 kPa) spray with a South Dakota isolate of WSMV using a 1:10 (weight:volume) maceration of WSMV-infected Arapaho wheat and 0.02 M potassium phosphate
buffer (pH 7.0) with 1% silica carbide added. Winter wheat lines with greater than 20% yield loss included Alliance, AP02T4342, BC97ROM-50W, CO960293, Dawn, HV9W02-942R, HV9W96-1383W, KS00F5-14-7, KS00F5-20-3-2, KS970197-8-9, Jagalene, NE01604, NE2528, NE03490, NH03609, NH03614, NI03418, NI03427, NW03681, OK01420, SD00265-3, SD01W064, SD01W070-3, SD01058, SD02279, SD02286, SD02480, SD03188, SD98W175-1, T151, T153, TX01A7326, TX01V5314, TX01V6008,TX99A0153-1, Vista, Wesley, and 98X0435. WSMV evaluation of winter wheat lines continued during Summer 2007, and data analysis is in progress. Evaluations of WSMV on spring wheat and of BPMV on soybean also continued during 2007.
PARTICIPANTS: Individuals: Marie A. C. Langham served this project as principal investigator and research director; Pat Wieland served this project as senior agricultural technician and was in charge of daily greenhouse care, collecting agronomic traits for field research, and laboratory assays; Smita Shrivastav served this project as a student research assistant doing laboratory, field, and greenhouse procedures. Partner Organizations: The following provided funding for research projects that contributed to the goals of this project: South Dakota Wheat Commission, South Dakota Soybean Research and Promotion Council, and North Central Soybean Research Program. Collaborators and Contacts: During this period, this project had collaborative relationships with Drs. Amir Ibrahim, Karl Glover, and Roy Scott (SDSU, Plant Science) for evaluation of plant materials. Dr. Louis Hesler (USDA-ARS, NCARL, Brookings, SD) also collaborated with this project on cereal and soybean aphid interactions.
Interaction with the Legume PIPE and its participants also advanced the virus management and education goals of this project. Additionally, interaction and contact between this project and NCERA 200 scientists and other participants advanced the research of this project. Training or Professional Development: In 2007, this project provided a training session on plant viruses for extension educators, interaction with the undergraduate and graduate teaching program at South Dakota State University, diagnostic assistance the South Dakota State Plant Diagnostic Clinic, and consulting with producers.
TARGET AUDIENCES: Target Audiences: During 2007, the principal target audiences of this project have been producers and extension educators. Producers cooperating with the soybean mosaic virus (SMV) survey were provided the opportunity for meetings during the sample collection visits to discuss the effects of SMV and bean pod mottle virus (BPMV) and were given sheets of information describing these problems. Extension educators were taught the effects of legume viruses during a training seminar. Graduate and undergraduate students were provided opportunities to work with virus infected plants during laboratories concentrating on plant viruses.
PROJECT MODIFICATIONS: There have been no major project modifications during 2007.
Impacts
Plant viruses cause dramatic impacts on South Dakota agriculture through disease effects and the resulting yield losses. Plant virus research in this project strives to increase the productivity of South Dakota producers through improved identification, knowledge, and management of plant viruses affecting soybeans, wheat, and other South Dakota commodities. Soybean mosaic virus (SMV) (Family: Potyviridae; Genus: Potyvirus) was found to be present in South Dakota. Damage caused by SMV will be increased by its synergistic relationship with bean pod mottle virus (BPMV) (Family: Comoviridae; Genus: Comovirus) and by the presence of the soybean aphid (Aphis glycines) which colonizes soybean. Management strategies for soybean should be amended to reflect this development. Evaluation of the impact of bean pod mottle virus (BPMV) (Family: Comoviridae; Genus: Comovirus) on soybean lines continues to demonstrate dramatic yield losses in infected lines and to reiterate the need
for the development of resistant soybeans. In evaluation of the impact of wheat streak mosaic virus (WSMV) (Family: Potyviridae; Genus: Tritimovirus) on spring wheat (Triticum aestivum L.), spring wheat lines inoculated with WSMV were rapidly infected and displayed severe symptoms. Yield in infected plots was significantly reduced (P<0.0001) in response to WSMV infection. All other factors (height, test weight, heading date, and virus incidence) were also affected by WSMV infection. Some lines evaluated in this research, such as Oxen and Ingot, were strongly affected in several characteristics. Other lines, such as Briggs, SD3540, and SD3720, were less affected; however, the impact of WSMV on all lines was greater than anticipated. The effects of WSMV may be mitigated by avoiding infection with temporal or spatial separation from winter wheat; however, the impact of WSMV on evaluated spring wheat lines indicates that care should be utilized in electing to plant spring wheat near
winter wheat. Evaluation of winter wheat lines for their reactions to WSMV is also an essential element of breeding for winter wheat lines that will have maximum performance in South Dakota. Yield losses of winter wheat varieties ranged widely (0.071%-38.21%). Selection of improved germplasm will reduce the impact of WSMV on winter wheat production in South Dakota. Also, WSMV infects many gramineous hosts and may be an important factor in the success or failure of the introduction of new grass crops in the Midwest. Improved winter wheat varieties will reduce the endemic level of WSMV that may act as inoculum for these new crops.
Publications
- Hesler, L.S., and Langham, M.A.C. 2007. Book review: Disease and Insect Resistance in Plants, D.P. Singh and A. Singh (2005). J. Econ. Entomol. 100:1496-1497.
- Ibrahim, A.M.H., Haley, S.D., Baenziger, P. S., Jin, Y., Langham, M.A.C., Rickertsen, J., Kalsbeck, S., Little, R., Ingemansen, J., Chung, O.K., Seabourn, B.W ., Bai,G.H., Chen, M-S., and McVey, D.V. 2008. Registration of 'Alice' wheat. Journal of Plant Registrations (Accepted).
- Langham, M. A. C. 2008. Plant pathogenic viruses. Chapter 4 In R. N. Triagiano, M. T. Windham, and A. S. Windham (eds.) Plant Pathology: Concepts and Laboratory Exercises. CRC Press. Boca Raton, FL. p. 21-34. (In Press and Early Release).
- Langham, M. A. C. 2008. Mechanical inoculation of plant viruses. Chapter 5 In R. N. Triagiano, M. T. Windham, and A. S. Windham (eds.) Plant Pathology: Concepts and Laboratory Exercises. CRC Press. Boca Raton, FL. p. 35-44. (In Press and Early Release).
- Langham, M., and Glover, K. 2007. Evaluation of wheat streak mosaic virus (Genus: Tritimovirus; Family: Potyviridae) on spring wheat yield and agronomic traits. (Abstract). Phytopathology 97:S61.
- Langham, M. A. C., Tolin, S. A., Sutula, C., Schwartz, H., Wisler, G., Karasev, A., Hershman, D., Giesler, L., Golod, J., Ratcliffe, S.T., and Cardwell, K. F. 2007. Legume/Virus PIPE: A new tool for disease management in legumes. (Abstract). Phytopathology 97:S61.
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Progress 01/01/06 to 12/31/06
Outputs
Wheat streak mosaic virus (WSMV) (genus Tritimovirus; family Potyviridae) causes the most important viral disease of winter wheat in the Great Plains resulting in annual losses due to endemic infection. During 2006, 67 winter wheat lines from the Advanced Yield Trials and the Crop Performance Trials were evaluated for their disease severity, stunting, yield loss, and reduction in test weight when infected with WSMV by high-pressure spray inoculation at Brookings, SD. An additional 81 lines from the Northern and Southern Regional Nurseries were also evaluated. Losses in spring wheat have been considered to be less severe due to spatial and temporal interruptions of the disease cycle. Losses were typically limited to spring wheat replanted in areas of winter wheat lost due to winter kill. Changes in South Dakota wheat production have resulted in increasing spatial and temporal overlaps of spring and winter wheat production and an increased WSMV incidence in spring
wheat. To address this problem, a study of the effects produced by WSMV on twelve spring wheat lines (Briggs, Granger, Ingot, Oxen, SD3540, SD3618, SD3623, SD3641, SD3720, SD3746, SD3827, and Walworth) continued this year. Four replications of completely randomized 8-row split plots of each wheat line were grown in Brookings. Half of the split plot was inoculated by high pressure (552 kPa) spray with a South Dakota isolate of WSMV using a 1:10 (weight:volume) maceration of WSMV-infected Arapaho wheat and 0.02 M potassium phosphate buffer (pH 7.0) with 1% silica carbide added. The second half was inoculated with only buffer and silica. Preliminary results from the first two years of this study indicate that WSMV infection significantly reduced yield (P < 0.0001), test weight (P < 0.0001), and height (P < 0.0001); however, seed protein was significantly increased (P < 0.0001). In other studies, bean pod mottle virus (BPMV) (genus Comovirus; family Comoviridae) was evaluated on ten
soybean cultivars and five cultivars from a multistate trial for its effects on disease severity, stunting, yield, test weight, node number, pod number, and seeds per pod. Reduction in yield, test weight, node number, pod number and seeds per pod were observed during 2006. Additionally, fifty sites from producer's soybean fields were surveyed for soybean mosaic virus (SMV) (genus Potyvirus; family Potyviridae). In each field, the upper two leaves from fifty random soybeans were collected in a W pattern with a minimum of four feet between each sample. Preliminary testing has indicated the presence of SMV which had not been detected previously in SD. The presence of SMV in SD will complicate the problem of the soybean aphid which is a vector for SMV.
Impacts
Wheat streak mosaic virus (WSMV) causes significant reductions in the yield, test weight, and heights of winter and spring wheat lines. The impact of WSMV on spring wheat is less documented than its impact on winter wheat. However, this research indicates major impacts on both types of wheat and that care should be utilized in electing to plant spring wheat near winter wheat and when overlapping spring and winter wheat in rotations. Bean pod mottle virus (BPMV) causes reductions in yield, pod number, seed per pod, and height when infecting soybean lines. This indicates the severe effects that BPMV has on soybean lines and the need for resistant varieties. Preliminary detection of soybean mosaic virus (SMV) increases the viral threat to soybean production in South Dakota. The presence of SMV will increase the impact of the soybean aphid, and synergistic interactions in plants dually infected with BPMV and SMV will increase the impact of viral diseases on soybean.
Publications
- No publications reported this period
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Progress 01/01/05 to 12/31/05
Outputs
Wheat streak mosaic virus (WSMV) (genus Tritimovirus; family Potyviridae) causes one of the most important winter wheat diseases in the Great Plains resulting in severe losses annually. However, losses in spring wheat have been considered to be less severe due to spatial and temporal interruptions of the disease cycle with losses typically limited to spring wheat replanted in areas of winter wheat lost due to winter kill. Today, changes in South Dakota wheat production have resulted in increasing overlaps of spring and winter wheat production and an increased WSMV incidence in spring wheat. To address this problem, a study of the effects produced by WSMV on twelve spring wheat lines (Briggs, Granger, Ingot, Oxen, SD3540, SD3618, SD3623, SD3641, SD3720, SD3746, SD3827, and Walworth) was initiated. Four replications of completely randomized 8-row split plots of each wheat line were grown in Brookings. Half of the split plot was inoculated by high pressure (552 kPa)
spray with a South Dakota isolate of WSMV using a 1:10 (weight:volume) macerate of WSMV-infected Arapaho wheat and 0.02 M potassium phosphate buffer (pH 7.0) with 1% silica carbide added. The second half was inoculated with only buffer and silica. Preliminary results indicate that WSMV infection significantly reduced yield (P < 0.0001), test weight (P < 0.0001), and height (P < 0.0001); however, seed protein was significantly increased (P < 0.0001). The preliminary yield losses include: Briggs 45.0%, Granger 52.5%, Ingot 57.0%, Oxen 61.4%, SD 3540 43.7%, SD 3628 51.1%, SD 3720 44.4%, SD 3746 60.1%, SD 3827 44.8%, and Walworth 46.5%. Losses in test weight ranged from 12.7% in Granger to 51.9% in Ingot. Stunting in spring wheat plants ranged from 25.3% in Briggs to 43.4% in Oxen. Increases in seed protein ranged from 0.2 % (Briggs) to 18.5% (Ingot) greater than the total protein percentage in seed from the buffer inoculation. Evaluations of the annual WSMV Winter Wheat nurseries were
also accomplished with analysis of the yield, test weight, stunting, and disease severity. In other studies, bean pod mottle virus (BPMV) (genus Comovirus; family Comoviridae) significantly decreased (P < 0.0075) the percentage of oil in seed from inoculated plants of ten soybean cultivars and experimental lines. BPMV also significantly increased (P < 0.05) the percentage of protein in these seed. The significant increase in protein percentage may be an effect of decreasing the amount of oil present in the seeds rather than a direct increase in the total amount of protein present in the seed. However, increases in seed protein occur when host plants are infected with other viruses (as observed in spring wheat).
Impacts
Wheat streak mosaic virus (WSMV) caused significant reductions in the yield, test weight, and heights of twelve spring wheat lines in preliminary data indicating that WSMV causes important disease impacts on spring wheat when infected. WSMV also increased the percentage of protein in the seed. The impact of WSMV on these spring wheat lines indicates that care should be utilized in electing to plant spring wheat near winter wheat and when overlapping spring and winter wheat in rotations. Additionally, bean pod mottle virus (BPMV) causes significant losses to the oil percentage in seed from infected plants. It also increases the protein percentage; however, this increase may be more a reflection of the decrease in oil than a true increase in protein. The impact of this reduction on soybean in addition to the reductions in yield, pod number, seed per pod, and height demonstrated in previous research indicates the severe effects that BPMV has on soybean lines and the need
for resistant varieties.
Publications
- Langham, M. A. C., Cihlar-Strunk, C. L., and Hoberg, A. E. 2005. Evaluation of high pressure spray inoculation of bean pod mottle virus on yield and test weight of soybean. (Abstr.) Phytopathology 95:S164.
- Strunk, Connie. 2005. BPMV Effects on ten experimental soybean lines and cultivars. MS. Thesis. July, 2005. South Dakota State University.
- Hesler, L. S., Riedell, W. E., Langham, M. A. C., and Osborne, S. 2005. Insect infestations, incidence of viral plant diseases, and yield of winter wheat in relation to planting date in the Northern Great Plains. Journal of Economic Entomology 98:2020-2027.
- Langham, M. A. C., and Glover, K. 2005. Effects of wheat streak mosaic virus (genus: Tritimovirus; family: Potyviridae) on spring wheat. (Abstr.) Phytopathology 95: S56.
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Progress 10/01/04 to 12/31/04
Outputs
Effects of bean pod mottle virus (BPMV) on the pod number and the seed number per pod of ten experimental soybean lines and cultivars demonstrated significant reductions. Analysis of the number of pods per plant and the number of seeds per pod when taken from the central five nodes demonstrated that pod number is significantly reduced (P < 0.0001) by BPMV infection. Reductions in the average number of pods ranged from 9.35% to 27.5% with the average loss ranging from 2-5 pods per all five nodes. The number of seeds per pod was also significantly (P < 0.0001) affected by BPMV. Reduction in the number of seeds per pod ranged from 8.23% to 26.21% with the greatest observed reduction being equivalent to a loss of 0.7 seed per pod. Thus, these two factors represent major contributions to observed yield reductions that were not explained by loss in test weight. Significant variations in the cultivar or experimental line responses to these two factors indicate that breeding
for improved varieties should include analysis of these two factors in performance. Node data indicated that there was no relationship between node position and pod and seed reduction over the range of nodes counted in this study. Evaluation of ten commercial and public cultivars, evaluation of insecticide treatments for control of BPMV, and multistate comparison of seed mottling as an index method for BPMV are in progress. Evaluations of wheat streak mosaic virus in winter wheat and in spring wheat are also in progress.
Impacts
Yield losses in soybean due to bean pod mottle virus (BPMV) are due in large part to reduction in pod numbers and in the number of seed per pod. Breeding for resistance to BPMV in soybean should include an analysis of these characters in order to minimize losses. Evaluation of the effects of wheat streak mosaic virus in winter and spring wheat lines is also in progress.
Publications
- No publications reported this period
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