Progress 09/01/10 to 08/31/15
Outputs
Target Audience:Our target audience will be policy makers making decisions about regulated sorghums and farmers in the Great Plains and world-wide that could benefit from improved sorghum production practices. Results will also inform industry representatives regarding best management practices for stewardship programs for the implementation of improved sorghums. Several policy makers from USDA, USEPA, USFDA and other organizations have been presented with our initial results. Changes/Problems:Due to the difficulty in making sufficient crosses using hand emasculation, only one shattercane population and one sorghum hybrid were used to create the shattercane x sorghum F2 population used in the 2012 fitness research. A delay in completing the experiments and the fourth objective occurred due to health issues of one of the participants. However, a modified model to predict the likelihood of resistance evolution is currently in development. What opportunities for training and professional development has the project provided?One PhD student was fully funded for a period four years. This student has since joined industry and still plans to complete his PhD. A second PhD student was funded on this project for several month. A PostDoctoral research associate was funded for a 3 month period in 2014. A small portion of the PI's salary was funded periodically throughout the granting period. Graduate students and PI's attended professional society meetings to present results of research and interact with key clientele groups (see below). How have the results been disseminated to communities of interest?Oral and poster presentations have been given at several professional society meetings, including the North Central Weed Science Society (2011, 2012, 2013, 2014), the Weed Science Society of America (2012, 2015), and the International Weed Science Congress (2012). Abstracts and peer reviewed journal articles have been published. A few extension presentations have been delivered. Several policy makers from USDA, USEPA, USFDA and other organizations were in attendance at the BRAG project directors meeting where our initial results were presented in June 2012 and 2013. We've also had several meetings with representatives of DuPont to discuss our results. What do you plan to do during the next reporting period to accomplish the goals?While this is our final report, we fully intend to publish at least three manuscripts currently in preparation from this research.
Impacts
What was accomplished under these goals?
This project provides the baseline information necessary to predict the probability of pollen-mediated gene flow from grain sorghum to shattercane and the potential for traits to become stable in the wild population. Objective 1 provided information on the likelihood that sorghum and shattercane will flower at the same time under various management practices. A two-year field experiment was conducted at two locations to quantify the synchrony of flowering of six populations of shattercane growing with three sorghum hybrids planted at three different sowing dates, with and without tillage. Sorghum and shattercane flowers were monitored weekly to assess the proportion of flowers that were dispersing pollen. This work was completed in 2012. We found that shattercane and sorghum flowering periods are nearly completely synchronous, indicating no barriers to pollen-mediated gene flow with regard to time of flowering. Objective 2 provided information on how long sorghum pollen is likely to survive in the air after release from the mother plant, which will provide information on how far it may travel before it dies. The settling velocity provides information on how quickly the pollen grains will fall to the earth resulting from gravitational pull. Laboratory experiments were conducted in 2014 to quantify the duration of sorghum pollen viability under various temperatures and relative humidity. The settling velocity of pollen grains was measured in a settling tower, which simulates an atmosphere without air flow. Results suggest that pollen grains survive within the atmosphere for up to five hours depending on temperature and humidity. Higher temperatures reduce survival time, higher humidity increases survival time. Settling velocity was comparable to that published for other sorghum and weedy species. Objective 3 provided information on the fitness of a segregating population resulting from a shattercane x sorghum cross relative to its parents. A two year field experiment was conducted at two locations to quantify the fitness of a shattercane x grain sorghum F2 population relative to grain sorghum and the wild-type shattercane population. Measurements included fecundity, seedling and seed survival, and germination. This experiment was completed in late 2013. Results indicate that the F2 population is equally as fit as either parent population, with the exception of the overwintering survival of the F2 seed in soil. Because the glumes of the F2 seed do not completely encapsulate the seed, they are more prone to mortality in soil. Results from this research and the literature are currently being used to develop a model that couples shattercane demography with pollen-mediated gene flow to predict the effects of various management practices (rotation of crop and herbicide mode of action) on the probability distribution of escape of an ALS resistant allele from ALS resistant sorghum to shattercane. Results show that development of ALS inhibiting herbicide resistance in shatttercane is far more sensitive to the extreme selection pressure from ALS inhibiting herbicides than to pollen-mediated gene flow. From a practical standpoint, results indicate that if shattercane is present in the system, maintaining its population at acceptable levels requires at least a three year rotation of herbicide modes of action.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Wortman, S. E., J. J. Schmidt and J. L. Lindquist. 2015. Weed suppressive potential of sudangrass is driven by interactions of root exudates and decomposing shoot residue. Crop Management 2014 13: 1: - doi:10.2134/CM-2013-0037-RS.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Werle, R., R. L. Martins, L. Sandell and J. L. Lindquist. 2014. ALS-inhibiting herbicide dose and plant size influence the control of ALS-resistant shattercane populations. Proceedings of the North Central Weed Science Society.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Werle, R., R. L. Martins, L. Sandell and J. L. Lindquist. 2015. Plant size and ALS-inhibiting herbicide dose influence the control of ALS-resistant shattercane populations. Proceedings of the Weed Science Society of America.
- Type:
Journal Articles
Status:
Other
Year Published:
2017
Citation:
Schmidt, J. J., J. F. Pedersen, M. L. Bernards, A. J. Lorenz. J. L. Lindquist. Flowering synchrony of grain sorghum and shattercane.
- Type:
Journal Articles
Status:
Other
Year Published:
2017
Citation:
Schmidt, J. J., S. E. Sattler, A. J. Lorenz, J. F. Pedersen and J. L. Lindquist. Fitness of sorghum, shattercane and their F2 hybrid.
- Type:
Journal Articles
Status:
Other
Year Published:
2017
Citation:
Schmidt, J. J., S. E. Sattler, A. J. Lorenz, J. F. Pedersen and J. L. Lindquist. Duration of grain sorghum pollen viability and its settling velocity.
- Type:
Other
Status:
Other
Year Published:
2013
Citation:
Schmidt, J. J., J. F. Pedersen, A. J. Lorenz, D. Pilson, S. Sattler, and J. L. Lindquist. 2013. Synchrony of flowering of 6 shattercane populations and 3 sorghum hybrids under various management practices. BRAG Project Director meeting 2013.
- Type:
Other
Status:
Other
Year Published:
2012
Citation:
Sahoo, L., J. Schmidt, M. Bernards, A. Lorenz, D. J. Lee, A. Martin, J. L. Lindquist, J. F. Pedersen, S. Sattler, R. Kaur, J. H. Wong, B. B. Buchanan, P. C. Lemaux. 2012. Pollen-mediated gene flow from sorghum to shattercane. BRAG Project Director meeting 2012.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2012
Citation:
Schmidt, J. J., S. E. Wortman and J. L. Lindquist. 2012. Allelopathy of sudangrass cover crop on green foxtail. Proceedings of the North Central Weed Science Society.
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Progress 09/01/13 to 08/31/14
Outputs
Target Audience: Our target audience will be policy makers making decisions about regulated sorghums and farmers in the Great Plains and world-wide that could benefit from improved sorghum production practices. Several policy makers from USDA, USEPA, USFDA and other organizations were in attendance at the BRAG project directors meeting where our initial results were presented in June, 2012. Changes/Problems: Due to the difficulty in making sufficient crosses using hand emasculation, only one shattercane population and one sorghum hybrid were used to create the shattercane x sorghum F2 population used in the 2012 fitness research. A delay in completing the experiments and the fourth objective occurred due to health issues of one of the participants. What opportunities for training and professional development has the project provided? Graduate students and PI's attended several professional society meetings to present results of research and interact with key clientele groups. How have the results been disseminated to communities of interest? Oral and poster presentations have been given at several professional society meetings. Abstracts and peer reviewed journal articles have been published. A few extension presentations have been delivered. Several policy makers from USDA, USEPA, USFDA and other organizations were in attendance at the BRAG project directors meeting where our initial results were presented in June 2012 and 2013. What do you plan to do during the next reporting period to accomplish the goals? The experiments required to complete the project have been completed. Our goal this year is to graduate Jared Schmidt with his PhD dissertation and submit 3-4 manuscripts to peer reviewed journals.
Impacts
What was accomplished under these goals?
This project will provide the baseline information necessary to predict the probability of pollen-mediated gene flow from grain sorghum to shattercane and the potential for traits to become stable in the wild population. Objective 1 will provide information on the likelihood that sorghum and shattercane will flower at the same time under various management practices. A two-year field experiment was conducted at two locations to quantify the synchrony of flowering of six populations of shattercane growing with three sorghum hybrids planted at three different sowing dates, with and without tillage. Sorghum and shattercane flowers were monitored weekly to assess the proportion of flowers that were dispersing pollen. This work was completed in 2012. We found that shattercane and sorghum flowering periods are nearly completely synchronous, indicating no barriers to pollen-mediated gene flow with regard to time of flowering. Objective 2 provides information on how long sorghum pollen is likely to survive in the air after release from the mother plant, which will provide information on how far it may travel before it dies. The settling velocity provides information on how quickly the pollen grains will fall to the earth resulting from gravitational pull. Laboratory experiments were conducted in 2014 to quantify the duration of sorghum pollen viability under various temperatures and relative humidity. The settling velocity of pollen grains was measured in a settling tower, which simulates an atmosphere without air flow. Results of these experiments are still being analyzed. Objective 3 provides information on the fitness of a segregating population resulting from a shattercane x sorghum cross relative to its parents. A two year field experiment was conducted at two locations to quantify the fitness of a shattercane x grain sorghum F2 population relative to grain sorghum and the wild-type shattercane population. Measurements included fecundity, seedling and seed survival, and germination. This experiment was completed in late 2013. Results indicate that the F2 population is equally as fit as either parent population, with the exception of the overwintering survival of the F2 seed in soil. Because the glumes of the F2 seed do not completely encapsulate the seed, they are more prone to mortality in soil. Results from this research and the literature are currently being used to develop a model that couples shattercane demography with pollen-mediated gene flow to predict the effects of various management practices (rotation of crop and herbicide mode of action) on the probability distribution of escape of an ALS resistant allele from ALS resistant sorghum to shattercane. Preliminary results show that development of ALS inhibiting herbicide resistance in shatttercane is far more sensitive to the extreme selection pressure from ALS inhibiting herbicides than to pollen-mediated gene flow.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Werle, R., J. Schmidt, J. Laborde, A. Tran, C. F. Creech and J. L. Lindquist. 2014. Shattercane x ALS-tolerant sorghum F1 hybrid and shattercane interference in ALS-tolerant sorghum. Journal of Agricultural Science 4:159-165.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Werle, R., J. J. Schmidt, J. Laborde, A. M. Tran, C. Creech and J. L. Lindquist. 2013. Shattercane x ALS-tolerant sorghum F1 hybrid and shattercane interference in ALS-tolerant sorghum. Proceedings of the North Central Weed Science Society.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Schmidt, J. J., S. Sattler, D. Pilson, A. J. Lorenz, J. F. Pedersen and J. L. Lindquist. 2013. Fitness of sorghum, shattercane and their F2 hybrid progeny. Proceedings of the North Central Weed Science Society.
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Progress 09/01/12 to 08/31/13
Outputs
Target Audience: Target audience for this project include the scientific community, industry, federal regulators, and potential users of grain sorghum with enhanced genetic traits. Changes/Problems: We applied for and received a one year no-cost extension to finalize the research and complete all manuscripts related to it. What opportunities for training and professional development has the project provided? One PhD student will complete his dissertation on this project in spring 2014. The PI presented results of this work and previous work at the International Weed Science Congress in Hangzhou China in 2012. Several undergraduate students have been involved and exposed to the research project. An additional PhD student working on a related project has been recruited. How have the results been disseminated to communities of interest? At this point results have primarily been disseminated through presentations at professional meetings and informally with our industry collaborators. What do you plan to do during the next reporting period to accomplish the goals? We will complete all the research objectives and begin finalizing manuscripts for submission to professional journals.
Impacts
What was accomplished under these goals?
A two year field experiment was conducted to quantify the synchrony of flowering of sorghum and shattercane and a manuscript is currently in preparation on this research. A two year field experiment was conducted to quantify the fitness of the shattercane x grain sorghum F2 population and was completed in late 2013. A manuscript is in preparation to summarize this research. Growth room experiments are currently underway to quantify the duration of sorghum pollen viability and settling velocity. A model to predict pollen-mediated gene flow and probability distribution of escape time is currently underway and should be completed by late 2014.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2012
Citation:
Schmidt, J. J., S. E. Sattler, A. J. Lorenz, J. F. Pedersen and J. L. Lindquist. 2012. Fitness of sorghum, shattercane and their F2 hybrid. Proceedings of the North Central Weed Science Society.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2012
Citation:
Lindquist, J. L. 2012. Pollen-mediated gene flow in sorghums: Implications for herbicide resistant sorghum. Proceedings of the 6th International Weed Science Congress, Hangzhou, Peoples Republic of China.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2012
Citation:
Schmidt, J. J., J. F. Pedersen, M. L. Bernards, A. J. Lorenz. J. L. Lindquist. 2012. Flowering synchrony of grain sorghum and shattercane. Proceedings of the Weed Science Society of America. 52:249.
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Progress 09/01/11 to 08/31/12
Outputs
OUTPUTS: Grain sorghum is an important food and feed crop throughout the world. The reduced digestibility of sorghum seed relative to other grains makes it a less efficient resource, even though it is highly adapted to growth in semiarid environments common to Africa, India, and the Southern and Western Great Plains of the USA. There has been considerable interest in modifying the quality traits of grain sorghum using transgenic technology to enhance its nutritional value to both humans and animals raised for human consumption. Using transgenic technology in sorghums is implicitly risky because there are several related species capable of interbreeding with sorghum, and it is not clear whether introduced traits will make weedy relatives even weedier. There has been no research conducted to determine how likely these traits will be transferred (gene flow) to the weedy relative, shattercane, or if they were transferred, how they would affect subsequent generations of the weed (potential weediness). Lack of such knowledge is an important problem because it limits our ability to assess the potential risks of introducing genetically modified grain sorghum into US agroecosystems. This research will provide regulators the information needed to make science based decisions about several issues that may arise as a result of deploying genetically modified sorghum. Specifically, the research will provide the baseline research to predict the probability of pollen-mediated gene flow from grain sorghum to shattercane and the potential for sorghum genes (traits) to become stable in the wild population. Our pollen-mediated gene flow results also will provide valuable information for identifying the appropriate isolation distance for managing the genetic purity of hybrid and elite inbred lines of grain sorghum. Finally, our results will be useful for developing good stewardship practices to minimize the escape of herbicide tolerant sorghums currently being developed using non-transgenic technologies. Our specific objectives were to: 1. Quantify the synchrony of flowering of multiple genotypes of grain sorghum and shattercane in situ, 2. Quantify duration of pollen viability and its settling velocity in several grain sorghum hybrids, 3. Quantify the fitness of the shattercane x grain sorghum F2 population relative to the wild type shattercane, 4. Utilize results from the above and our prior research in models to predict pollen-mediated gene flow and the probability distribution of escape time. To date, we are concluding the second year of field experiments at two locations to quantify the synchrony of flowering of six populations of shattercane growing with three sorghum hybrids planted at three different sowing dates. Results of this experiment will be published in the refereed literature. 2012 was the first year of a field experiment to evaluate the fitness of a shattercane x sorghum F2 population relative to the parent lines. Results of these experiments have been and will be presented at annual professional meetings in 2012. PARTICIPANTS: Professor Lindquist is the Project Director for this work. Dr. Bernards has left the University of Nebraska and will only participate peripherally. Mr. Jared Schmidt is conducting this research as part of his PhD program in Agronomy at UNL. Dr. Pedersen is providing support in crossing shattercane x sorghum in the greenhouse. Dr. Lorenz will provide quantitative genetics support. Mr. Darren Binder is a Research Technologist providing field research support for this project. TARGET AUDIENCES: Our target audience will be policy makers making decisions about regulated sorghums and farmers in the Great Plains and world-wide that could benefit from improved sorghum production practices. Several policy makers from USDA, USEPA, USFDA and other organizations were in attendance at the BRAG project directors meeting where our initial results were presented in June, 2012. PROJECT MODIFICATIONS: Due to the difficulty in making sufficient crosses using hand emasculation, only one shattercane population and one sorghum hybrid were used to create the shattercane x sorghum F2 population used in the 2012 fitness research.
Impacts
Previous research showed that synchronously flowering shattercane can receive pollen from sorghum at a distance of at least 200 m from a relatively small sized source population. Proportion of florets within a shattercane panicle receiving sorghum pollen was as high as 2.46% at that distance. Within the source, rate of hybridization was up to 16%. Both wind speed and direction were important predictors of the probability of hybridization, especially at distances greater than 60 m from the source. Results of our flowering synchrony research suggest that shattercane and sorghum flowering are nearly completely synchronous regardless of shattercane population, sorghum maturity group, or planting date.
Publications
- Lindquist, J. L. 2012. Pollen-mediated gene flow in sorghums: Implications for herbicide resistant sorghum. Proceedings of the 6th International Weed Science Congress, Hangzhou, Peoples Republic of China.
- Schmidt, J. J., J. F. Pedersen, M. L. Bernards, A. J. Lorenz. J. L. Lindquist. 2012. Flowering synchrony of grain sorghum and shattercane. Proceedings of the Weed Science Society of America. 52:249.
- Schmidt, J. J., J. F. Pedersen, M. L. Bernards, J. Lindquist and A. J. Lorenz. 2011. Synchrony of flowering in grain sorghum and shattercane. Proceedings of the North Central Weed Science Society. 66:98.
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: Grain sorghum is an important food and feed crop throughout the world. The reduced digestibility of sorghum seed relative to other grains makes it a less efficient resource, even though it is highly adapted to growth in semiarid environments common to Africa, India, and the Southern and Western Great Plains of the USA. There has been considerable interest in modifying the quality traits of grain sorghum using transgenic technology to enhance its nutritional value to both humans and animals raised for human consumption. Development of sorghums with improved digestibility traits is highly desirable, but using transgenic technology to accomplish this is implicitly risky because there are several related species capable of interbreeding with sorghum, and it is not clear whether those traits will make weedy relatives even weedier. There has been no research conducted to determine how likely these traits will be transferred (gene flow) to the weedy relative called shattercane, or if they were transferred, how they would affect subsequent generations of the weed (potential weediness). Lack of such knowledge is an important problem because it limits our fundamental understanding of gene transfer and potential hybridization between grain sorghum and shattercane. This limits our ability to assess the potential risks of introducing genetically modified grain sorghum into US agroecosystems. This research will provide regulators the information needed to make science based decisions about several issues that may arise as a result of deploying genetically modified sorghum. Specifically, the research will provide the baseline research to predict the probability of pollen-mediated gene flow from grain sorghum to shattercane and the potential for sorghum genes (traits) to become stable in the wild population. Our pollen-mediated gene flow results also will provide valuable information for identifying the appropriate isolation distance for managing the genetic purity of hybrid and elite inbred lines of grain sorghum. Finally, our results will be useful for developing good stewardship practices to minimize the escape of herbicide tolerant sorghums currently being developed using non-transgenic technologies. Our specific objectives were to: 1. Quantify the synchrony of flowering of multiple genotypes of grain sorghum and shattercane in situ, 2. Quantify duration of pollen viability and its settling velocity in several grain sorghum hybrids, 3. Quantify the fitness of the shattercane x grain sorghum F2 population relative to the wild type shattercane, 4. Utilize results from the above and our prior research in models to predict pollen-mediated gene flow and the probability distribution of escape time. To date, we have conducted one year of field experiments at two locations to quantify the synchrony of flowering of six populations of shattercane growing with three sorghum hybrids planted at three different sowing dates. This experiment will be replicated at both locations in 2012. Results of the first experiment will be presented at annual professional meetings in late 2011 and early 2012. PARTICIPANTS: Professor Lindquist is the Project Director for this work. Dr. Bernards has left the University of Nebraska and will only participate peripherally. Mr. Jared Schmidt is conducting this research as part of his PhD program in Agronomy at UNL. Dr. Pedersen is providing support in crossing shattercane x sorghum in the greenhouse. Dr. Lorenz will provide quantitative genetics support. Mr. Darren Binder is a Research Technologist providing field research support for this project. TARGET AUDIENCES: Our target audience will be policy makers making decisions about regulated sorghums and farmers in the great plains and world-wide that could benefit from improved sorghum production practices. These groups have not been engaged to date. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
In progress.
Publications
- No publications reported this period
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