Progress 07/01/23 to 06/30/24
Outputs
Target Audience:During this reporting period, a global network of collaborators was successfully assembled to collect and exportParthenium hysterophorus(parthenium weed) seed for the research project via APHIS guidelines. The proposal stated parthenium weed seed would be imported with the help of collaborators from 3 countries, but with the aid of the global network of parthenium weed experts, wesuccessfully imported 7 global biotypesfromAustralia, Israel, Pakistan, South Africa, Vietnam, Mexico, Argentina, as well as two Texas, USbiotypes. Through this global network, the impact of the research was boosted as well as the breadth of the target audience. Expanding the target audience and the parthenium weed biotypes to be evaluated to encompass the major countries withdiverse habitat and climate types will increase the significanceof the ecological datasets from this research. The core of this global network of parthenium weed experts is Dr. Steve Adkins at the University of Queensland, Australia, Dr. Asad Shabbir with the New South Wales Department of Primary Industries in NSW, Australia, Dr. Maor Matzrafi at the Volcani Institute in Ramat-Yishay, Israel, Dr. Heiki Vibrans at the College of Mexico in Mexico City, Mexico, Dr. Guillermo Chantre at the National University of the Southin Bahia Blanca, Argentina. The sharing of these ecological datasets of global parthenium weed biotypes through scientific publications will help connect global weed scientists who have previously been limited to studying biotypes from their home country. From the global and collaborative nature of this project, this can foster a broader audience of academics, researchers, and practitioners around the world. Delivering science-based knowledge in global newsletters, like the Asian and Pacific Weed Science Society (APWSS) newsletter, and webinars on platforms of our global collaborators can help reach groups in parts of Asia and Africa that desperately need this knowledge to manage parthenium weed in their farming communities when this weed out-competing crops hasled to loss of cropland and food shortages. During the project period, a resourceful panel of stakeholders comprised of US and global researchers was assembled and regularly consulted to provide advice and input to ensure the hypothesis and methodologies of each experiment were optimized and to ensure the project milestones are met in a timely fashion. From Clemson University, Dr. Matthew Cutulle, anExtension Vegetable Weed ScienceSpecialistwas added as a field site collaborator inthe 'common garden experiment' to evaluate the growth of global parthenium weed populations under 3 nitrogen ratesin Charleston, SC, which isa newly invaded range in the US. Parthenium weed is also a major problem in vegetable crops, allowingthis collaboration with Dr. Cutulle to reach a broader audience of vegetable producers. Additionally, Dr. Liberty Galvin, an Extension Weed Science Specialist atOklahoma State University wasadded as a field site collaborator inthe 'common garden experiment' as Oklahoma is on the northern range of parthenium weed's current range and can reach a different audience of small grains commodity groups. The third field site collaborator isDr. Muthukumar Bagavathiannan, Research Weed Scientistat Texas A&M University asparthenium weed management is becoming a major problem in cotton production systems. Additionally,Dr. Joshua McGinty, an Extension Cropping Systems Specialist located in Corpus Christi, TX, was also consulted for their expensive experience with parthenium management in cotton in the Texas Gulf coast and South Texas.From thestakeholder advisory panel we will assemble with the diverse crop systemnetworks at Clemson University, Oklahoma State University, Texas A&M University, and Cornell University, this project will be able to reach a larger audience of US producers,commodity groups, industry professionals, and extension professionals to share the important linkages between weed-crop competition and climate change. For the second major experiment evaluating stress-induced changes across the global parthenium weed biotypesin a high-throughput phenotyping center, two plant stress physiologists at Cornell University, Dr. Tim Setter and Dr. Magdalena Julkowska, have joined as collaborators. We aimuncover the physiological switch between the C3-C4 intermediate nature of this highly adaptable weed species. The target audience with this physiology-level experiment greatly expands to encompass all disciplines ofplant scientists, particularly those interested in improving C3 pathways in crops, and offers a novel approach to studying weed physiology with the use of a high-throughput phenotyping center. In the classroom at Cornell University, the postdoctoral fellow, Dr. Kezar.created new, interactive, lecture materials for a more engaging way to teachintegrative weed management in the upper-level weed science course. Within the research lab, Dr. Kezar mentors and leads a team of 4 undergraduate students to help the lab carry out a variety research tasks. From this mentorship, two of these undergraduate students signed to conduct their senior thesis projects under the guidance of Dr. Kezar. These two students are from different backgrounds, one being a farm girl from central New York while the other student was raised in Beijing, China, bringing a great opportunity to teach and encourage the next generation ofagriculturalists. Changes/Problems:Objective 1. The treatment structure for Objective 1 has been modified to exclude the factor of competition against C3 and C4 crops. The competition with C3 and C4 crops was of interest to study because parthenium weed is a C3-C4 intermediate species and may either take advantage of or be limited by the combined effects of average versus hightemperatures, drought stress or well-watered conditions, and ambient (420 ppm) versus elevated (700 ppm)CO2 concentrations. A much bigger question that this project may address is determining the capacity for the C4 pathway and if/when there is a 'switch' that parthenium weed utilizes to tolerate abiotic stress conditions and ifthis 'switch' differs between native and invasive biotypes.Physiologists have identified that it is a true C3-C4 intermediate through carbon isotope labeling, but all stress physiology studies to-date have been limited to 1 biotype and a few observation periods, making the 'switch' point from C3- to C4-dominant or vice versa unclear within or across biotypes. Starting in August 2024, we will use a novel approach to evaluate 8 global biotypes in a high-throughput phenotyping center, with the aid of two Cornell plant stress physiologists Dr. Tim Setter and Dr. Magdalena Julkowska, who run the high-throughput phenotyping center at Cornell. Thus, with the novel approach of using the high-throughput phenotyping center, we can no longer keep the crop competition component because having more than one plant per potwould interfere with theimagery. Updated methodology: For 14 days, aligned with the critical growth period from the 6-8 leaf rosette stage to the bolting stage, parthenium weed will be automatically watered to control (75% FC) levels or drought stress conditions (20% FC) using an automated plant transport and imaging system.Transpiration rate data will be acquired daily from the weight of pots before and after watering, with thisdata also beingused to model the relationship to water potential and water holding capacity.Three types of image data, near-infrared (NIR), visible (color), and fluorescence (FLUO) images will be acquired daily from different views (top view and side view) in the phenotyping system for the classification of phenotypic traits (Berger et al. 2010; Chen et al. 2014; Granier and Vile 2014; Khanna et al. 2014).Color imaging will assessrelative growth rate, nutritional status, and health status.Multi-spectral imaging measuringvarious pigments involved in photosynthesis willprovidea more comprehensive understanding of photosynthetic efficiency.Infrared thermography (IRT) will measurethe leaf or canopy temperature whileNIR imaging will providea measure related to plant water contentand NDVI. Parameters such as Fv/Fm (the maximum quantum yield of photosystem II), NPQ (non-photochemical quenching), and qP (photochemical quenching- a measure of stress), chlorophyll index, and anthocyanin index can be measured using fluorescence imaging and used to track changes in photosynthetic activity daily. Additionally, we will measure ABA levels and starch content in the leaves at 7- and 14-days after the initiation of drought stress and 7 days after recovery from the drought stress period. The data will be collected between August 2024 and December 2024 and will still be completed on time. The researchers have previously contacted Dr. Christopher Phillips about the proposed updates. Objective 2. The treatment structure for Objective 2has been slightly modified for logistical reasons because it was not possible to have global field locations import multiple global populations of parthenium weed and have those plants in a field environment due to strict regulations in India and Australia, in particular. Instead, the common garden experiment now featuresUS-based collaborators and field locations in Ithaca, NY (Cornell University), College Station, TX (Texas A&M University), Stillwater, OK (Oklahoma State University), and Charleston, SC (Clemson University). Additionally, the researchers determined evaluating drought as a factor in this experiment would be too complicated logistically and instead will reflect naturalrainfall conditions of each field locations. Instead, the impact of soil Nitrogen levels in the 4 field environments will be evaluated as a treatment factor. The level of soil Nitrogen is of interest because soil fertility is hypothesized to promote parthenium weed invasion and establishment indiverse regions around the globe and we are wondering if high soil fertility levels in agricultural settings may further promote the risk of invasion and establishmentof parthenium weed.The researchers have previously contacted Dr. Christopher Phillips about the proposed updates. What opportunities for training and professional development has the project provided?Training of Dr. Kezar, the postdoctoral fellow, has included one-on-one mentorship withscientists of various disciplines to develop new skills in modeling in CLIMEX andmap generation in ARCGIS (collaboration with Dr. Asad Shabbir), microbial assays (collaboration with Dr. Jenny Kao-Kniffin),interpreting high-throughput imagery data (collaboration with Dr.Magdalena Julkowska), and leaf tissue assays (collaboration with Dr. Tim Setter). Professional development activities have included participation inCornell DEI workshop program asa NextGen Faculty Fellow, and a Cornell writing workshop for developing a faculty application packet. Additionally, Dr. Kezar leads and coordinates the undergraduate helpers in the DiTommaso lab and is mentoring two undergraduate students in their Senior Thesis projects. How have the results been disseminated to communities of interest?Oral presentations at the Weed Science Society of America and North Eastern Weed Science Society conferences have communicated the modeling work of 'Parthenium hysterophorus(L.) in the Americas: Predicting suitable habitats beyond its native range under future climatic conditions'with the weed science community. The larger plant science community will soon be reached with the accepted review 'Biology of Invasive Plants 5.Parthenium hysterophorus(L.)' in the Invasive Plant Scienceand Management journal. Dr. Kezar was brought into the review paper effort by 4 other global parthenium weed expert and she wrote major sections covering the distribution, habitat, invasion risk, and population dynamics of this weed of global significance. What do you plan to do during the next reporting period to accomplish the goals?Objective 1. Using high-throughput phenotyping to understand environmental by genotypic drivers of Parthenium hysterophorus(L.) photosynthesis and phenotypic plasticity Collect data between August 2024 and December 2024. Analyze results and present results in the 2025 Weed Science Society meetings. Publish in early Spring 2025. Objective 2. Common garden approach to evaluate globally invasiveParthenium hysterophorus(L.) at the edges of its native range Finish year 1 data collection across all 4 field sites in late August 2024. Run year 1 data analysis and present results at the 2024 ASA-CSA-SSSA Annual Meeting andthe 2025 Weed Science Society meetings. Establish the year 2 field locations by May 2025 and have a succession plan in place for the Ithaca, NY location in case the postdoctoral fellow leaves for a new position in mid-summer 2025 at the conclusion of this NIFA-AFRI Postdoctoral Fellowship. Objective 3.Parthenium hysterophorus(L.) in the Americas: Predicting suitable habitats beyond its native range under future climatic conditions Finish writing manuscript draft by August2024, rounds of editing with global collaborators, and publish thereafter in Fall 2024.
Impacts
What was accomplished under these goals?
Objective 1.The treatment structure for Objective 1 has been slightly modified to target a larger research questions (See: Changes/Problem). Now, the experiment asks a larger question of the capacity for the C4 pathway in this C3-C4 intermediate species and if/when there is a 'switch' that parthenium weed utilizes to tolerate abiotic stress conditions and ifthis 'switch' differs between native and invasive biotypes underthe combined effects oftemperature stress, drought stress, and ambient (420 ppm) versus elevated (700 ppm)CO2 concentrations.Physiologists have identifiedparthenium weeda true C3-C4 intermediate through carbon isotope labeling, but physiology studies to-date have been limited to 1 biotype and a few observation periods, making the 'switch' point from C3- to C4-dominant relatively unknown. The growth and phenotypic responses captured by daily imagery will create a robust model to compare against various crop species and inform future research directions. The data will be collected between August 2024 and December 2024. If we can ask these larger questions of plant stress physiology of thisC3-C4 intermediate species and potential differences across biotypes and climate conditions this could reach a much larger target audience of the plant science community. Objective 2.The treatment structure for Objective 2has been slightly modified for logistical reasons(See: Changes/Problem). The experiment is now centered onUS-based collaborators and field locations in Ithaca, NY (Cornell University), College Station, TX (Texas A&M University), Stillwater, OK (Oklahoma State University), and Charleston, SC (Clemson University). The problem this project addresses is, for the first time, understanding if parthenium weed biotypes from 5 different global regions exhibiting various life history traits across different environments, or within the same growing environment, could aid demographic success across various agronomic regions and environments. Additionally, if the soil-Nitrogen level influences the invasive growth potential of any biotypes when grown without competition or when in competition with the native flora. This spring, parthenium weed seed was overseeded in greenhouse flats for emergence ratesto be observed without the risk of parthenium weed seed entering the field environment. Before transplanting, the field environment received 3 levels of Nitrogen addition (none added, N rate for200 bu corn, half of the N rate for 200 bu corn). Currently in-field observations of growth, phenology, and NDVI, are being recorded. Mid-season soil samples will be taken at each location to measure extracellular enzyme activity to inform us about microbial activity in response to N additions and interactions with the parthenium weed biotypes grown alone and in competition with the native flora.Plants will be terminated at flowering so there is no risk of weed seed entering the soil seedbank. The experiment will be repeated once more in summer 2025 for a total of 8 site years. From evaluating5 global biotypes in 4 different growing regions of the US, we can better understand the emergence and growth dynamics along with the thermal/rainfall requirements of the global populations. This data willbe fitted as a model to predict differences in biotypes, risk of range expansion or niche shifts, and weed management timings, such as the most optimal times for herbicide applications. The microbial activity dataset will help answer a largely unknown question of the below-ground interactions that are hypothesized to aid parthenium weed invasion and establishment in a wide variety of habitats. Additionally, at Cornell we are conducting a herbicide screening of all 8 global populations as a side objective to help weed scientists, producers, and policy makers understandthe chemicalmanagement options for parthenium weed. The resistance status of parthenium weed has only been reportedin croplands or orchards inTexas,Florida, the Dominican Republic, Cuba, Columbia, and Brazil. We willevaluate the efficacy of selected POST herbicides (0. 0.5, and 1X rate) commonlyused in cultivated areas for control of global populations of parthenium weed at 2 growth stages (4-6 leaf rosette, bolting) and thereafter confirm and characterize the level of resistance, if/when occurring via a dose response assay. This experiment has already been started,is set to be completed in October 2024, andwill yield an additional publication. Objective 3. The southern US is the northernmost part of the native range of parthenium weed, but as of recently, something has spurred increased occurrences of parthenium weed in more northern latitudes in South Carolina and more western regions, particularly in southern California. As prevention is the best way to tackle invasive plants, it is critical to understand where parthenium weed could complete a life cycle in the current climate as well as the potential for establishment in irrigated environments when water is not a limiting factor, in a climate change scenario of +3C, and the combined effects of +3C temperatures and irrigated conditions. Plant localities were taken from GBIF (2024), REMIB Database (2024), and various literature and newsletter sources. Locality data were refined by (1) correcting coordinate errors, where possible, (2) removing duplicate records, (3) removing instances with a locational error or an artificial cultivation of parthenium weed (e.g., university campuses, botanical gardens), and (4) coordinates older than 50 year and/or with no additional locations near them were considered transient and removed. Then, we developed a CLIMEX distribution model of parthenium weed in the Americas. The CLIMEX parameter values for temperature and moisture indices were adjusted to fit the climates of North America, Mexico, Central America, and South America. An irrigation scenario (winter, 0.5 mm day-1, and summer, 1.0 mm day-1) was added to the basic CLIMEX model and was used to develop a predictive distribution model for parthenium weed under the current climate and under climate change scenarios. All CLIMEX model data output files were imported into the ArcMap version 10 program (ESRI, Environmental Systems Resource Institute, Redlands, CA, USA) using relevant shapefiles, and from this, all the maps were developed. Based on CLIMEX models, it appears that parthenium weed has the capacity to spread into the midwestern and coastal regions in the USA and further into the central region of South America (Kriticos et al. 2015), but there are no specific studies in its native range to understand the extent of natural competition and enemies keeping populations in check. Within its native range in the USA, isolated weed populations in the semi-arid west and southwest are at risk of expanding along the west coast and into parts of the Midwest, with these important agronomic systems commonly under irrigation being particularly at risk due to increased soil moisture availability (Kriticos et al. 2015; Shabbir et al. 2023). As prevention is the best way to handle weed invasions, it is critical to understand where parthenium weed could complete a life cycle in the current climate as well as future climate scenarios. The target audience for this work are weed scientists,stakeholders, producers, and policy makers that may better understand regions of the United States and other regions of the Americas that have croplands orcritical habitats at risk of invasion of this troublesome weed species.
Publications
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2024
Citation:
Shabbir, A., Bajwa, A. A., Mao, R., Kezar, S., Dorji, S., Adkins, S.W. (2024) Biology of Invasive Plants 5. Parthenium hysterophorus (L.). Invasive Plant Science and Management.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2024
Citation:
Kezar, S., Shabbir, A., Adkins, S., DiTommaso, A. (2024). Parthenium hysterophorus�L. in the Americas: Predicting suitable habitats beyond its native range under future climatic conditions. Oral presentation at: the Weed Science Society of America Annual Meeting. San Antonio, TX. 28 January. (accepted).
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2024
Citation:
Kezar, S., Shabbir, A., Adkins, S., DiTommaso, A. (2024). Parthenium hysterophorus L. in the Americas: Predicting suitable habitats beyond its native range under future climatic conditions. Oral presentation at: the North Eastern Weed Science Society Annual Meeting. Boston, MS. 10 January. (accepted).
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