Source: UNIVERSITY OF FLORIDA submitted to
CONTROL OF INVASIVE RUELLIA SIMPLEX THROUGH INDUCED STERILIZATION AND IMPROVED MANAGEMENT IN INVADED NATURAL AREAS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
SPECIAL GRANT
Reporting Frequency
Annual
Accession No.
0222403
Grant No.
2010-34135-21100
Cumulative Award Amt.
$119,901.00
Proposal No.
2010-03016
Multistate No.
(N/A)
Project Start Date
Sep 1, 2010
Project End Date
Aug 31, 2013
Grant Year
2010
Program Code
[AH]- Tropical & Subtropical Research/T STAR
Recipient Organization
UNIVERSITY OF FLORIDA
G022 MCCARTY HALL
GAINESVILLE,FL 32611
Performing Department
Environmental Horticulture
Non Technical Summary
Ruellia simplex (syn. R. tweediana, R. brittoniana) is a popular ornamental landscape plant in Southern states. This non-indigenous species has escaped cultivation and is highly invasive in the Virgin Islands, Puerto Rico and 9 states including Florida. The wild types and cultivated forms have high female fertility and fruiting by self-pollination, and seeds have high germination rates. In this project we propose a two-pronged control approach for this invasive species involving plant breeding and ecosystem restoration. The first objective is to breed new sterile cultivars of Ruellia simplex as an alternative to invasive forms used in the landscape. Three different breeding approaches will be used to develop sterile plants: induction of mutations by use of irradiation; ploidy manipulations to develop triploids; and use of interspecific wide crosses. Mutants, triploids and hybrids will be evaluated for ornamental value, sterility, growth rate, and vegetative spread in greenhouse and multi-location field trials. Breeding lines will be evaluated and selected after 18-month trials at three Florida locations (Citra, Quincy, and Fort Pierce). Selected breeding lines will be made available under material transfer agreements to commercial floriculture companies for independent trials, following protocols developed by the UF/IFAS Office of Research Intellectual Property Office (Florida Agricultural Experimental Station and Florida Seed Producers, Inc.). Final selections will be subjected to approval by the UF/IFAS cultivar release committee prior to commercial release, and then to the UF/IFAS Assessment for non-native plants Infraspecific Taxon Protocol for an exemption on the Invasive Plants list (http://plants.ifas.ufl.edu/assessment/infraspecific_taxon_protocol.h tml). The second objective is to improve management of R. simplex populations in invaded natural areas and study the restoration of native species. We will determine optimal R. simplex control with glyphosate in a controlled field experiment in a R. simplex-invaded natural area. Factors evaluated will be timing (season) of initial application and follow up treatments. We will analyze plant community composition up to 18 months after control applications, including reinvasion of R. simplex and recolonization of native species. Finally, we will assess potential for R. simplex invasion by emergence from the seedbank in upland areas.
Animal Health Component
40%
Research Effort Categories
Basic
20%
Applied
40%
Developmental
40%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2012120108050%
2042120310020%
2062120310010%
2132120310020%
Knowledge Area
204 - Plant Product Quality and Utility (Preharvest); 206 - Basic Plant Biology; 201 - Plant Genome, Genetics, and Genetic Mechanisms; 213 - Weeds Affecting Plants;

Subject Of Investigation
2120 - Herbaceous perennials and decorative greens;

Field Of Science
1080 - Genetics; 3100 - Management;
Goals / Objectives
Ruellia simplex has formed naturalized populations in 28 counties dispersed throughout the state. Currently there are tall and dwarf cultivars available of R. tweediana in purple, pink and white flower colors. All of them are female fertile with the exception of 'Purple Showers'. New sterile Ruellia cultivars with novel flower colors and growth habits have great potential for landscape use in the Southern U.S as an alternative to the invasive wild type and fertile cultivars. Another important control approach for management of invasive R. tweediana is to promote recolonization of the native plant community following initial clearing of R. tweediana in natural areas. The broad geographic naturalization of this species and its impact on native plant communities has motivated research to control this species. Understanding the longer term influence of control treatments on both R. tweediana population dynamics and recolonization of native plant communities is the next step in determining effective management of invasive R. tweediana populations. Objectives 1. To breed new sterile cultivars of Ruellia as an alternative to invasive forms of R. simplex used in the landscape. i. Mutation breeding. ii. Ploidy manipulations. iii. Interspecific hybridizations. iv. Greenhouse and multi-location field trials of triploid progenies and mutants. 2. To improve initial control and analyze the transition to restoration of native species in R. simplex-dominated natural areas. i. Field trials to optimize glyphosate herbicide application time and follow up control measures and analyze of post control plant community composition ii. Assessment of potential R. simplex invasion by emergence from the seedbank in upland areas.We expect that a few sterile Ruellia breeding lines with desirable ornamental traits and controlled vegetative spread will be obtained using the different breeding approaches described in this project. Alternatively, we may obtain plants with low female fertility and/or inviable seed. R. simplex breeding lines with purple, pink, white and white with purple throat flower colors have been developed by classical breeding at UF over the last two years. We expect to obtain sterile forms in these four flower colors using two approaches (mutation breeding and ploidy manipulation). Additionally, we aim to obtain sterile breeding lines with novel flower colors and growth habits by use of interspecific hybridizations. As a result of the herbicide management study, we expect that one initial herbicide application time will emerge as more effective, likely due to increased translocation of glyphosate to belowground structures. Ruellia simplex control will be more effective with 2 follow up applications. We also anticipate that native species recolonization will vary with treatment and plot location, and be primarily influenced by effectiveness of R. simplex control and proximity to native species populations. We expect that R simplex seed bank density will decline with increasing distance from the R. simplex-invaded riparian zone. We also expect that seedbanks in upland areas immediately adjacent to R. simplex source populations will be substantial.
Project Methods
1. Genetic sterilization of R. tweediana: Female sterility will be evaluated through hand pollinations in the greenhouse with fertile male parents; male fertility will be assessed by observation of pollen grain staining using a microscope. Fertilization of native R. caroliniensis with R. tweediana pollen is sometimes possible (Freyre and Tripp, in preparation). Thus, male fertile R. tweediana breeding lines will be used as parents in hybridizations with R. caroliniensis to verify that the native plant species plant populations will not be at risk. Breeding lines selected for sterility will be further evaluated for landscape performance and fruiting in multi-location trials. Prior to commercial cultivar release, final selections will be subjected to approval by an IFAS cultivar release committee and the IFAS Assessment for non-native plants Infraspecific Taxon Protocol. Genetic sterilization of R. tweediana is currently in process using two approaches as described below. a. Mutation breeding using X-ray and gamma irradiation: Irradiation treatments were performed on R. tweediana in 2007 and 2008. Subsequently, over 1200 plants were obtained from irradiation treatments performed in 2008. Approximately 40 breeding lines with different flower colors and growth habits were selected due to no fruit production. All selections will be further tested to confirm female and male sterility. b. Ploidy manipulations: Polyploidization of R. tweediana plants with different flower colors was attempted in December 2008 using oryzalin as described (Jones et al., 2008). A total of 160 treated plants were grown and analyzed for ploidy level using flow cytometry, and a total of 15 presumed tetraploid plants were obtained. Cytological studies involving chromosome counts in root tips or developing pollen grains will be needed to confirm ploidy level. Initial interploidy hybridizations were initiated in September 2009. Preliminary results indicate that many developing fruit abort before the seeds are mature, therefore embryo rescue in tissue culture will be required to obtain triploid progenies. Seedlings obtained from interploidy hybridizations will be initially evaluated for ploidy level using flow cytometry. Selected triploid progenies will be further tested for sterility and landscape performance. 2. Control of invasive populations of R. tweediana In an established R. tweediana population at Paynes Prairie Preserve State Park (the subject of study for Hupp (2007)), we will apply R, tweediana control treatments in a fully replicated design, varying 1) the timing of the initial clearing herbicide application, and 2) the intensity of follow up herbicide control efforts. Plant community dynamics following control efforts will be observed, and recolonization of both the invader and native plant species will be monitored at repeated measures plots using percent cover and biomass as response variables. We will follow treatment outcomes for 18 months following initial clearing to identify management strategies that are most likely to promote restoration of native species following R. tweediana removal.

Progress 09/01/12 to 08/31/13

Outputs
Target Audience: Ornamental greenhouse and nursery growers, land managers, restoration practitioners, environmental protection agencies, environmental consulting firms. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? PhD student Christine Wiese and undergraduate students Madeline Bottenhorn andCandice Prince completed research under this project. How have the results been disseminated to communities of interest? Participation in conferences, EDIS publication. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Breeding: Three clones bred at UF were selected after multilocation trials in 2011: purple R10-102, pink R10-105 and white R10-108. R10-105 had about 6% and 5% of the number of viable seeds per plant compared to invasive R. simplex and pink cultivar ‘Chi Chi’, respectively, and it was not approved for cultivar release. Seed from R10-105 from open pollination in the three field trials was collected and germinated, obtaining 142 progenies. These progenies were transplanted to the field in Citra in 2012, and 29 pink flowering plants were selected based on ornamental value and apparent lack of or very low fruiting. They were propagated vegetatively and grown in a greenhouse in Gainesville. In 2013, 19 pink flowering plants were selected for replicated field trials in Citra and pot trials in a poly house in Gainesville. Fifteen of the selected plants were also trialed in replicated field trials in Fort Pierce. At each trial, plants were distributed in a completely randomized block design with three replications. Plants were evaluated weekly in Citra and Gainesville for 15 weeks, and every four weeks in Fort Pierce for 14 weeks for landscape performance, flowering and fruiting. Pink-flowered R10-105-Q54 was selected based on superior and consistent performance at all locations, as well as very low fruit production. Herbicide treatments: The study site is located in the cypress preserve area of Paynes Prairie State Preserve, Alachua County, Florida. The site is a bald-cypress (Taxodium distichum) dominated floodplain forest habitat with a near mono-culture of R. simplex in the herbaceous vegetation layer. A tributary to Sweetwater Branch bisects the bald-cypress preserve area and supplies storm-water run-off from near-by urban areas. Twelve 3m by 3m plots were randomly located in the bald-cypress preserve area of Paynes Prairie State Preserve. Six plots were located on both sides of a Sweetwater branch tributary where it bisects the bald-cypress preserve area. Each plot was divided into four 1.5m by 1.5m subplots designated by permanent markers. Treatments included four levels of herbicide applications (0, 1, 2 or 3 herbicide applications) and two application initiation seasons (fall or spring-initiated application). Percent cover of each species present was measured using a modified Mueller-Dombois scale before the first glyphosate application and every three months after that, with the final data collection occurring at three months after the third spring glyphosate application. Pre-treatment percent plant cover data was collected in October 2010. The first fall season herbicide application was applied immediately after. Spring pre-treatment plant cover data was collected in April 2011 and the first spring season herbicide application was applied immediately after. A 2% solution of glyphosate was applied with a compressed-air backpack sprayer at each herbicide application. Total species richness, native species richness, and Floristic Assessment Quotient for Wetlands (FAQwet index; Ervin et al., 2006) were calculated from percent cover data to assess the effect of glyphosate applications on the quality of resulting cover. FAQWet index is a calculated score used to determine overall floristic quality of wetland habitats when coefficients of conservatism are not available for the habitat or location (Ervin et al., 2006). Results from the experiment on herbicide control of the invasive Ruellia simplex have been analyzed and written for a journal article accepted for publication by Ecological Restoration. Seedbank composition Seedbank samples were collected from 24 sampling locations within the study site. A sample was collected at each of the twelve R. simplex-invaded plots randomly selected for glyphosate treatment in the bald-cypress preserve area of Paynes Prairie State Preserve. An additional twelve samples were collected from locations that were randomly selected within the bald-cypress preserve area of Paynes Prairie that had no R. simplex invasion present. Six sites were randomly selected on each side of the Sweetwater Branch tributary with no R. simplex present in aboveground cover to make up the twelve samples. Seedbank samples were collected in October 2010 (fall samples) and again in March 2011 (spring samples). Seedbank samples were collected and spread over the top of a soil layer in trays located on a ponded greenhouse bench. Four “blank” control trays were randomly located on the greenhouse bench between those trays with seedbank samples to assess any possible seed contamination. Water levels were maintained at a constant depth between 0-1 cm of the soil surface. The seedling emergence method was used to evaluate diversity and density of the seedbank. Once seedlings were large enough to survive transplant, they were transplanted into 4-in azalea pots (1 seedling per pot) containing soil mix and maintained on a ponded greenhouse bench. Once seedlings had produced reproductive material or were otherwise identifiable, they were identified to species and recorded. Both the fall and spring seedbank assays ran for six months. Total species richness, native species richness, total seed density, native seed density, and FAQWet indices (Ervin et al. 2006) were calculated for each treatment. Results from the seedbank assay of Ruellia simplex-invaded floodplain forest have been analyzed and written for a journal article which will be submitted for publication when an internal review of the manuscript is complete. Data analysis evaluating control of Ruellia simplex during the second year after herbicide application has been completed and is being written for publication.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Freyre R, A. Moseley, C. Reinhardt-Adams, A.G.W. Knox, S.B. Wilson and Z. Deng. 2013. Breeding Ruellia spp. at the University of Florida. Proc. VIIth International Symposium on New Floricultural Crops. Eds.: G. Facciuto and M.I. Sanchez. Acta Hort. 1000:423-428.
  • Type: Other Status: Awaiting Publication Year Published: 2013 Citation: Adams, C.A., C. Wiese, L.C. Lee, S.B. Wilson, A. Smith, and R. Freyre. 2013. Managing Mexican petunia (Ruellia simplex C. Wright) in the home landscape. EDIS publication, University of Florida, IFAS. ENH. (in press).
  • Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2013 Citation: Wiese, C., C. Reinhardt-Adams, and A. M. Smith. 2013. Experimental research informs control of Mexican petunia (Ruellia simplex) in natural areas and home-gardens. Proc. Fl. State Hort. Soc. 20:x-x. (in press).


Progress 09/01/10 to 08/31/13

Outputs
Target Audience: Ornamental greenhouse and nursery growers, land managers, restoration practitioners, environmental protection agencies and environmental consulting firms. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? The following students have conducted research work under this project: Adrienne Smith (PhD student) Adam Moseley (undergraduate honors student) Madeline Bottenhorn (undergraduate honors student) William Mazzota (undergraduate honors student) Candice Prince (undergraduate honors student) How have the results been disseminated to communities of interest? Through conference presentations, professional and industry publications, University of Florida internet publications, visits to ornamental plant growers. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Fifteen Ruellia hybrids bred at UF in Gainesville were selected for field trials in 2011. Plants were clonally propagated, and nine plants per line, plus the wild type and three cultivars were evaluated in southeastern, north central and northwestern FL (Fort Pierce, Citra and Quincy) using a completely randomized block design with three replications of three adjacent plants per plot in each location. Assessments were performed monthly for each plant for landscape performance, flowering and fruiting. Data were analyzed after 24 weeks of field evaluations. Three clones: purple R10-102, pink R10-105 and white R10-108 were selected because they had better landscape performance, growth habit and flowering than the commercial cultivars ‘Purple Showers’, ‘Chi Chi’ and ‘Snow White’, respectively. R10-105 had about 6% and 5% of the number of viable seeds per plant compared to invasive R. simplex and ‘Chi Chi’, respectively, and it was not approved for cultivar release. Seed from R10-105 from open pollination in the three field trials was collected and germinated, obtaining 142 progenies. These progenies were transplanted to the field in Citra in 2012, and 29 pink flowering plants were selected based on ornamental value and apparent lack of or very low fruiting. They were propagated vegetatively and grown in a greenhouse in Gainesville. In 2013, 19 plants were selected for replicated field trials in Citra and pot trials in a poly house in Gainesville. Fifteen of the selected plants were also trialed in replicated field trials in Fort Pierce. At each trial, plants were distributed in a completely randomized block design with three replications. Plants were evaluated weekly in Citra and Gainesville for 15 weeks, and every four weeks in Fort Pierce for 14 weeks. In 2012, fruitless R10-102 and R10-108 were approved for cultivar release by the UF/IFAS Invasive Plants Task Force and by the UF/IFAS Cultivar Release Committee. They were named ‘Mayan Purple’ and ‘Mayan White’, respectively and their patent applications were filed in July 2012. In 2013, ‘Mayan Purple’ and ‘Mayan White’ were commercially available in Home Depot stores in south and north central Florida. In 2013, pink-flowered R10-105-Q54 was selected based on superior and consistent performance at all locations, as well as very low fruit production. This clone was approved for cultivar release by the UF/IFAS Invasive Plants Task Force and by the UF/IFAS Cultivar Release Committee. It was named ‘Mayan Pink’ and its patent application was filed in December, 2013. As a two-pronged approach to Ruellia control, this research project also involves field experiments to eradicate invasive populations in natural areas using glyphosate treatments. Twelve 3m x 3m plots were randomly selected in an area of the cypress preserve area of Paynes Prairie State Preserve with R. simplex invasion. Treatments included four 2% glyphosate application times (0, 1, 2 or 3 herbicide applications) and 2 application seasons (fall or spring).Total species richness, native species richness, and Floristic Assessment Quotient for Wetlands (FAQwet) were calculated from percent cover data to assess the effect of glyphosate applications on the quality of resulting cover. Research suggests that land managers could achieve acceptable levels of control of R. simplex with a single application of glyphosate and that season of glyphosate application is not crucial to level of control. Long-term monitoring is in progress to determine how glyphosate applications will affect the long-term control of R. simplex and the reemergence of native vegetation. Seedbank composition was determined by collecting soil samples at each of the 12 R. simplex-invaded plots that were treated with glyphosate. Each seedbank sample was set in the greenhouse for germination during 6 months. Seedlings were identified to species and recorded. Total species richness, native species richness, total seed density, native seed density, and FAQWet indices were calculated for each treatment. More than 80% of species that germinated from the seedbank were native. Few R. simplex seedlings germinated during the study. This suggests that there is potential for restoring the native vegetation community from the seedbank if barriers to native seed germination and establishment in the field can be overcome. Acceptable levels of control of R. simplex cover in Paynes Prairie, FL was achieved with a single 2% application of glyphosate. Season of glyphosate application is not crucial to level of control. Findings suggest that there is potential for restoring the native vegetation community from the seedbank if barriers to native seed germination and establishment can be removed. Data analysis indicated acceptable control of R. simplex with glyphosate application and no differences in R. simplex control based with regard to frequency or season of application. Additionally, data indicate high native and total species richness in the intact seedbank of R. simplex-invaded floodplain forest, suggesting high potential for revegetation of the native plant community. Knowledge of Ruellia simplex response to herbicide control with glyphosate will influence managers scheduled control activities. As the data indicate that frequency of herbicide application did not increase control, managers can reduce time in the field required for additional glyphosate applications. Average Ruellia simplex cover in field plots was reduced from 78% to 14% as of the final data collection period.

Publications

  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Freyre, R., A. Moseley, S.B. Wilson and G. W. Knox. 2012. Breeding and evaluating for landscape performance and fruitlessness in Mexican Petunia (Ruellia, Acanthaceae). HortScience 47:1245-1251.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2012 Citation: Freyre, R., A. Moseley, C. Reinhardt-Adams, G. Knox, and S.B. Wilson. 2012. Limiting invasive Ruellia populations via breeding sterile cultivars and developing efficient control in natural areas. HortScience (abstract) 47:S197.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2012 Citation: Wilson, S.B., G.W. Knox, R. Freyre, and Z. Deng. 2012. Characterizing the invasive potential of ornamental plants. Proc.XXVIII Int. Hort. Cong. on Science and Horticulture for People. Acta Hort. 937:1183-1192.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2012 Citation: Mazzota, W.C., C. Reinhardt Adams, and C. Wiese. 2012. Comparing floodplain forest vegetation dynamics on Ruellia simplex (Mexican petunia; Syn. R. tweediana) invaded and un-invaded land using a seed bank study. Undergraduate Research Symposium (poster).
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Freyre, R., A. Moseley, G. W. Knox and S.B. Wilson. 2012. Fruitless Ruellia simplex R10-102 (Mayan Purple) and R10-108 (Mayan White). HortScience 47:1808-1814.
  • Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2013 Citation: Freyre, R., S.B. Wilson and G.W. Knox. 2013. Breeding Ruellia and trialing for sterility at the University of Florida. Int. Plant Prop. Southern Region Mtg. Athens, GA.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Freyre, R., S.B. Wilson and G.W. Knox. 2013. Breeding Ruellia and trialing for sterility at the University of Florida. Int. Trials Conf., Kennett Square, PA.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2012 Citation: Wiese, C., C. Reinhardt Adams, L. C. Cobb, and A. Smith. 2012. Influence of initial soil nutrients and seedbank on Ruellia simplex control and resulting native species establishment. University of Florida Water Institute Symposium (poster).
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Freyre R., A. Moseley, C. Reinhardt-Adams, A.G.W. Knox, S.B. Wilson and Z. Deng. 2013. Breeding Ruellia spp. at the University of Florida. Proc. VIIth Int. Symp. New Floricultural Crops. Eds.: G. Facciuto and M.I. Sanchez. Acta Hort. 1000:423-428.
  • Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2013 Citation: Wiese, C., C. Reinhardt-Adams, and A. M. Smith. 2013. Experimental research informs control of Mexican petunia (Ruellia simplex) in natural areas and home-gardens. Proc. Fl. State Hort. Soc. 20:x-x.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: Wiese, C., C. Reinhardt-Adams, L. C. Cobb. 2014. Effect of season and number of glyphosate applications on control of invasive Ruellia simplex. Ecological Restoration.
  • Type: Other Status: Other Year Published: 2013 Citation: Adams, C.A., C. Wiese, L.C. Lee, S.B. Wilson, A. Smith, and R. Freyre. 2013. Managing Mexican petunia (Ruellia simplex C. Wright) in the home landscape. EDIS publication, University of Florida, IFAS.
  • Type: Journal Articles Status: Accepted Year Published: 2014 Citation: Freyre, R. and S.B. Wilson. 2014. Ruellia simplex R10-105-Q54 ('Mayan Pink'). HortScience.
  • Type: Other Status: Awaiting Publication Year Published: 2014 Citation: Freyre, R. 2014. Ruellia: New colors and non-invasive cultivars for an outstanding landscape plant. AmericanHort.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: Smith, A.M., C.R. Adams and S.B. Wilson. 2014. Mexican petunia (Ruellia simplex) invasions: management challenges and research opportunities. Wildland Weeds.


Progress 09/01/11 to 08/31/12

Outputs
OUTPUTS: Patent applications for Mayan PurpleTM (R10-102) and Mayan WhiteTM (R10-108) were filed in June, 2011, and commercial licensing is in process. Acceptable levels of control of R. simplex cover in Paynes Prairie, FL was achieved with a single 2% application of glyphosate. Season of glyphosate application is not crucial to level of control. Findings suggest that there is potential for restoring the native vegetation community from the seedbank if barriers to native seed germination and establishment can be removed. PARTICIPANTS: Freyre, R., Moseley, A., Bottenhorn, M., Bell, Z. , Reinhardt-Adams, C., Wiese, C., Cobb, L. Smith, A., Mazzota, W. Environmental Horticulture Dept., UF, Gainesville, FL; Knox, G.W., Aldrich, J. NFREC, UF, Quincy, FL; Wilson, S. B., Muller, K., Frey, P. IRREC, UF, Fort Pierce, FL; Deng, Z., Jones, J. GCREC, UF, Wimauma, FL; Mellich, T.A. MFREC, UF, Apopka, FL. TARGET AUDIENCES: Commercial growers of ornamental plants, land managers, restoration practitioners, environmental protection agencies and environmental consulting firms. PROJECT MODIFICATIONS: One-year no-cost extension.

Impacts
Fifteen Ruellia plants bred at UF in Gainesville were selected for field trials in 2011. Plants were clonally propagated, and 9 plants per line, plus the wild type and 3 cultivars were evaluated in southeastern, north central and northwestern FL using a randomized block design with 3 replications of 3 adjacent plants per location. Assessments were performed monthly for each plant for landscape performance, flowering and fruiting. Data were analyzed after 24 weeks of field evaluations. Three clones: purple R10-102, pink R10-105 and white R10-108 were selected because they had better landscape performance, growth habit and flowering than the commercial cultivars Purple Showers, Chi Chi and Snow White. Fruitless R10-102 and R10-108 were approved for cultivar release by the UF/IFAS Invasive Plants Task Force and by the UF/IFAS Cultivar Release Committee. R10-105 had about 6% and 5% of the number of viable seeds per plant compared to invasive R. simplex and Chi Chi, respectively, so additional research on its progeny is necessary before its release is approved. Ruellia hybridizations performed in 2011 resulted in 217 seedlings. These were initially evaluated in the greenhouse, and 142 plants were selected for 2012 summer field trials in Citra, FL. Additionally, a second set of hybridizations resulted in 53 seedlings that are currently being evaluated in a greenhouse in Gainesville, FL. As a two-pronged approach to Ruellia control, this research project also involves field experiments to eradicate invasive populations in natural areas using glyphosate treatments.Twelve 3m x 3m plots were randomly selected in an area of the cypress preserve area of Paynes Prairie State Preserve with R. simplex invasion.Treatments included four 2% glyphosate application times (0, 1, 2 or 3 herbicide applications) and 2 application seasons (fall or spring).Total species richness, native species richness, and Floristic Assessment Quotient for Wetlands (FAQwet) were calculated from percent cover data to assess the effect of glyphosate applications on the quality of resulting cover. Research suggests that land managers could achieve acceptable levels of control of R. simplex with a single application of glyphosate and that season of glyphosate application is not crucial to level of control. Long-term monitoring is in progress to determine how glyphosate applications will affect the long-term control of R. simplex and the reemergence of native vegetation. Seedbank composition was determined by collecting soil samples at each of the 12 R. simplex-invaded plots that were treated with glyphosate.Each seedbank sample was set in the greenhouse for germination during 6 months.Seedlings were identified to species and recorded.Total species richness, native species richness, total seed density, native seed density, and FAQWet indices were calculated for each treatment.More than 80% of species that germinated from the seedbank were native.Few R. simplex seedlings germinated during the study.This suggests that there is potential for restoring the native vegetation community from the seedbank if barriers to native seed germination and establishment can be removed.

Publications

  • Freyre, R., A. Moseley, C. Reinhardt-Adams, G. W. Knox, S.B. Wilson and Z. Deng. 2012. Breeding Ruellia spp. and other ornamental plants at the University of Florida. Acta Horticulturae (in press).
  • Freyre R. and Z. Deng. 2012. Breeding Ruellia and Caladium at the University of Florida. Acta Horticulturae (in press).
  • Freyre, R., A. Moseley, G. W. Knox and S.B. Wilson. 2012. Breeding and evaluating for landscape performance and fruitlessness in Mexican Petunia (Ruellia, Acanthaceae). HortScience (in press).
  • Freyre, R., A. Moseley, S.B. Wilson and G. W. Knox. 2012. Fruitless Ruellia simplex R10-102 (Mayan Purple) and R10-108 (Mayan White). HortScience (submitted).
  • Mazzota, W.C., C. Reinhardt Adams, and C. Wiese. 2012. Comparing floodplain forest vegetation dynamics on Ruellia simplex (Mexican petunia; Syn. R. tweediana) invaded and un-invaded land using a seed bank study. Journal of Undergraduate Research (submitted).
  • Wiese, C., C. Reinhardt Adams, L. C. Cobb, and A. Smith. 2012. Influence of initial soil nutrients and seedbank on Ruellia simplex control and resulting native species establishment. University of Florida Water Institute Symposium. (poster)


Progress 09/01/10 to 08/31/11

Outputs
OUTPUTS: Fourteen Ruellia breeding lines are currently in commercial trials in Florida. Two hybrids Ruellia elegans x R. matudae and R. elegans x R. roseae have novel flower colors and are currently in commercial trials in Texas. Significant short-term reduction of invasive R. simplex cover in Paynes Prairie, FL was achieved with a single 2% glyphosate treatment with minimal negative impacts on adjacent native vegetation. PARTICIPANTS: Freyre, R.; Moseley, A.; Bottenhorn, M.; Ellison, K. Reinhardt-Adams, C. Environmental Horticulture Dept., UF, Gainesville, FL. Knox, G.W; Aldrich, J. NFREC, UF, Quincy, FL Wilson, S. B.: Muller, K. IRREC, UF, Fort Pierce, FL. Deng, Z.; Jones, J. GCREC, UF, Wimauma, FL. Mellich, T.A. MFREC, UF, Apopka, FL. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
All Ruellia seeds from hybridizations performed in 2010 between several interploidy combinations, morphotypes and different species of Ruellia, and seeds from selfing 4x individuals and mutants were sown. A total of 495 seedlings were obtained. Initially, all progenies were grown in a greenhouse at Gainesville, Florida. R. simplex breeding lines were selected for good growth habit, vigor, good flowering, and absent or reduced fruit formation. Two hundred and seventy selected Ruellia plants were grown in a preliminary field trial with one replication in early spring in Wimauma, FL. Fourteen breeding lines were selected for further replicated field trials and were clonally propagated. Nine plants per breeding line, plus the wild type and three cultivated forms (as controls) were evaluated in south eastern Florida (Fort Pierce), north central Florida (Citra) and north Florida (Quincy) using a randomized design with three replications of three adjacent plants per location. Assessments are being performed monthly for each plant for landscape performance, flowering and fruiting. Simultaneously, these lines are being trialed in a commercial setting. Data will be analyzed after 24 weeks of field evaluations. Breeding lines that have better landscape performance, growth habit and flowering than the currently existing commercial cultivars Purple Showers, Chi chi and Snow White, and that have no fruiting or significantly lower fruiting than the invasive wild type R. simplex, will be selected for cultivar release. As a two-pronged approach to Ruellia control, this research project also involves field experiments to eradicate invasive populations in natural areas using glyphosate treatments. Twelve 3m x 3m plots were randomly selected in an area of the cypress preserve area of Paynes Prairie State Preserve with R. simplex invasion. Treatments included four 2% glyphosate application times (0, 1, 2 or 3 herbicide applications) and two application seasons (fall or spring application). Significant short-term reduction in R. simplex cover was achieved with one glyphosate treatment with minimal negative impacts on adjacent native vegetation. Additional data will be collected over the next 2 years to assess long-term control. Seedbank composition was determined by collecting soil samples at each of the 12 R. simplex-invaded plots that were treated with glyphosate. As controls, 12 samples were collected from randomly selected locations with no R. simplex invasion present within the cypress preserve area of Paynes Prairie, and 12 samples from a separate cypress dominated floodplain forest site with no history of exotic species invasion. Each seedbank sample was set in the greenhouse for germination. R. simplex did not readily germinate from seedbank samples collected in either fall (October) or spring (March) under greenhouse conditions. Soil nutrient levels were determined for a total of 24 soil samples collected at the Paynes Prairie cypress preserve site. Soil analysis suggest that total species richness, native species richness as well as percent cover by R. simplex is related to soil nutrient levels, particularly, P, Mg, and soil pH.

Publications

  • No publications reported this period