Search Results

You are looking at 51 - 60 of 60 items for

  • Author or Editor: John M. Ruter x
  • All content x
Clear All Modify Search
Free access

Eugene K. Blythe, Jeff L. Sibley, and John M. Ruter

Stem cuttings of golden euonymus (Euonymus japonicus `Aureo-marginatus'), shore juniper (Juniperus conferta `Blue Pacific'), white indian hawthorn (Rhaphiolepis indica `Alba'), and `Red Cascade' miniature rose (Rosa `Red Cascade') were successfully rooted in plugs of a stabilized organic substrate that had been soaked in aqueous solutions of the potassium salt of indole-3-butyric acid (K-IBA) at 0 to 75 mg·L–1 before inserting the cuttings. Cuttings were rooted under intermittent mist in polyethylene-covered greenhouses with rooting periods appropriate for each species. Rooting percentages showed some increase with increasing auxin concentration with juniper cuttings, but were similar among treatments for the other three species. Number of roots per rooted cutting increased with increasing auxin concentration with cuttings of juniper, Indian hawthorn, and rose, and was greatest using around 60 mg·L-1 K-IBA for cuttings of juniper and Indian hawthorn and 30 to 45 mg·L-1 K-IBA for cuttings of rose.

Free access

Ryan N. Contreras, John M. Ruter, and David A. Knauft

American beautyberry (Callicarpa americana) is a deciduous shrub native to the southeast United States and is grown primarily for its metallic-purple fruit that develop in the fall. There are also pink- and white-fruiting and variegated forms but these traits are rare in nature and there is no information available regarding their inheritance. Also, there is confusion regarding self-compatibility and the presence of apomixis in Callicarpa L. Crosses were performed to investigate the genetics of fruit color, self-compatibility, and apomixis in american beautyberry. Test crosses between C. americana (CA) and C. americana ‘Lactea’ (CAL) suggested that white fruit is recessive to purple. White fruit appears to be controlled by a single recessive gene for which we propose the name white fruit and the gene symbol wft. Although there were only a limited number of progeny grown, crosses between CA and ‘Welch’s Pink’ suggest that purple is dominant to pink. Test crosses between CAL and ‘Welch’s Pink’ are needed to draw conclusions; however, we propose that purple, pink, and white fruit are controlled by an allelic series for which we suggest the gene symbols Wft > wft p > wft. Segregation ratios suggested that all progeny in the study developed through sexual hybridization. All genotypes used in the current study were self-compatible.

Full access

Eugene K. Blythe, Jeff L. Sibley, Ken M. Tilt, and John M. Ruter

In five experiments, singlenode cuttings of `Red Cascade' miniature rose (Rosa) were treated with a basal quick-dip (prior to insertion into the rooting substrate) or sprayed to the drip point with a single foliar application (after insertion) of Dip `N Grow [indole-3-butyric acid (IBA) + 1-naphthaleneacetic acid (NAA)], the potassium salt of indole-3-butyric acid (K-IBA), or the potassium salt of 1-naphthaleneacetic acid (K-NAA); a single foliar spray application of Dip `N Grow with and without Kinetic surfactant; or multiple foliar spray applications of Dip `N Grow. Spray treatments were compared with their respective basal quick-dip controls {4920.4 μm [1000 mg·L-1 (ppm)] IBA + 2685.2 μm (500 mg·L-1) NAA, 4144.2 μm (1000 mg·L-1) K-IBA, or 4458.3 μm (1000 mg·L-1) K-NAA}. Cuttings sprayed with 0 to 246.0 μm (50 mg·L-1) IBA + 134.3 μm (25 mg·L-1) NAA, 0 to 207.2 μm (50 mg·L-1) K-IBA, or 0 to 222.9 μm (50 mg·L-1) K-NAA resulted in rooting percentages, total root length, percent rooted cuttings with shoots, and shoot length similar to or less than control cuttings. Exceptions were cuttings sprayed with 0 to 2.23 μm

(0.5 mg·L-1) K-NAA, which exhibited shoot length greater than the control cuttings. Addition of 1.0 mL·L-1 (1000 ppm) Kinetic organosilicone surfactant to spray treatments resulted in greater total root length and shoot length. Repeated sprays (daily up to seven consecutive days) had no or negative effects on root and shoot development.

Free access

Frank Henning, Timothy J. Smalley, Orville M. Lindstrom, and John M. Ruter

On 1 May 2004, a 4 × 2 split-plot experiment was initiated in Athens, Ga., on Rhododendron ×kurume `Pink Pearl'. The four main-plot treatments were low irradiance, low irradiance May–October, low irradiance November–May, and high irradiance (high and low correspond to average daily PPF of 23.6 and 10.4 mol·m-2·d-1). The two subplot fall fertigation treatments were 75 mg·L-1 of nitrogen (N) and 125 mg·L-1 N. Plant stem tissue was harvested monthly from November to March, and analyzed for freeze resistance (LT50). Maximum quantum efficiency of PSII (Fv/Fm) was analyzed monthly with a Mini-pam photosynthesis yield analyzer. No interactions existed between fertilizer application and light intensity and the 125 mg·L-1 N fertilizer treatment reduced freeze resistance of azalea stems throughout the study. Fall fertilization had no effect on fluorescence and no interactions existed between fertilizer and irradiance treatments. In November, plants that received low irradiance May–October were less freeze-resistant than plants from the high-irradiance treatment. However, in January, plants that received low irradiance throughout the study were more freeze-resistant than plants that received the high-irradiance treatment. In November, Fv/Fm was higher in the low irradiance and low irradiance November–May treatments. In February and March, Fv/Fm was lower in the low May–November treatment that received low irradiance during summer than the low November–May treatment that received low winter irradiance. The use of shade to reduce irradiance may delay the acquisition of freeze resistance in fall. However, shade may reduce photosystem damage and increase a plants ability to acquire and maintain greater freeze resistance.

Free access

Chris A. Martin, John M. Ruter, Robert W. Roberson, and William P. Sharp

Hydration and elemental absorption of two commercially-available polyacrylamide gels (A and B) were studied in response to a 24-hr soak time in Hoagland's solution concentrations of either 2X, 1X, 0.5X, 0.25X, 0.125X or 0X (deionized water). Elemental absorption of gel specimens was observed and analyzed within the gel matrix on a Philips CM12S STEM equipped with an EDAX 9800 plus EDS unit for micro x-ray analysis. Thick sections were cut on dry glass knives using an RMC MT6000 ultramicrotome. Surface analysis of bulk specimens was made with an AMR 1000A SEM plus PGT1000 EDS unit. Overall, gel hydration decreased quadratically as solution concentration increased linearly; however, hydration for gel A was generally greater than for gel B. Surface analysis of gel samples revealed the presence Ca, K, P, S, Fe, and Zn for both gels. An analysis within the matrix of gel B revealed the presence of Ca, K, P, S, Fe, and Zn; however, an analysis within the matrix of gel A revealed the presence of Zn, and Fe only. The increased absorptive capacity of gel A appeared to be coupled to reduced migration of salts into the gel matrix.

Free access

Chris A. Martin, William P. Sharp, John M. Ruter, and Richard L. Garcia

Paclobutrazol at 0 and 750 μl·liter–1 was sprayed on shoots of Feijoa sellowiana O. Berg. and Ligustrum japonicum Thunb. grown under similar production regimes in central Arizona (subtropical desert) and southern Georgia (humid temperate). Five months after application, Feijoa and Ligustrum leaves were generally smaller and thicker in Arizona than in Georgia. Arizona leaves were thicker than those in Georgia because of more layers of palisade and spongy mesophyll cells. Compared with leaves from control plants, paclobutrazol 1) increased Feijoa leaf area in Georgia, 2) decreased Ligustrum leaf area at both locations by ≈50%, and 3) decreased leaf thickness of both species in Arizona. Arizona Feijoa leaves had trichomes on adaxial and abaxial surfaces, whereas Georgia Feijoa leaves had trichomes on abaxial surfaces only. Paclobutrazol increased trichome frequency on adaxial surfaces of Arizona Feijoa leaves. Stomatal frequency of Georgia Feijoa leaves was about doubled by paclobutrazol. Reflectance of near-infrared radiation by paclobutrazol-treated Feijoa leaves was 1.4 times higher than that of nontreated leaves in Georgia and 1.9 times in Arizona. Near-infrared reflectance by Georgia Ligustrum leaves was 1.3 times higher than by Arizona Ligustrum leaves and was not affected by paclobutrazol. Leaf reflectance of photosynthetically active radiation (PAR) by Arizona Feijoa was higher than by Georgia Feijoa. Paclobutrazol increased PAR reflectance by Arizona Feijoa leaves. In contrast, Georgia Feijoa PAR reflectance was decreased by paclobutrazol. Paclobutrazol or location did not affect Ligustrum PAR reflectance. Chemical name used: (2RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)pentan-3-ol (paclobutrazol).

Free access

Ryan N. Contreras, John M. Ruter, James S. Owen Jr., and Andy Hoegh

Japanese-cedar has been underused in landscapes of the United States until recent years. There are now over 100 cultivars, many of which are grown in the southeast of the United States. Performance of cultivars has been described from U.S. Department of Agriculture (USDA) Zone 6b to USDA Zone 7b; however, there are no reports on how cultivars perform in USDA Zone 8. The current study was conducted to measure chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid content and assign visual color ratings to determine if there was a relationship between pigment values and perceived greenness, which generally is regarded as a desirable and potentially heritable trait. Total chlorophyll (P = 0.0051), carotenoids (P = 0.0266), and the ratio of total chlorophyll to carotenoids (P = 0.0188) exhibited a positive relationship with greenness after accounting for season and tree effects. In contrast, the ratio of chlorophyll a to chlorophyll b did not have an effect on greenness. There was a linear relationship between total chlorophyll and carotenoid regardless of season (summer R 2 = 0.94; winter R 2 = 0.88) when pooled across 2 years. The observed correlation between chlorophyll and carotenoid content suggests they could be used interchangeably as predictors of greenness. There were large differences in rainfall between the 2 years that may have resulted in additional variation. Furthermore, the climate in which the evaluation was conducted differs greatly from the native distribution of japanese-cedar occurring in China and Japan.

Full access

John D. Lea-Cox, Cindy Zhao, David S. Ross, Theodore E. Bilderback, J. Roger Harris, Susan D. Day, Chuanxue Hong, Thomas H. Yeager, Richard C. Beeson Jr, William L. Bauerle, Andrew G. Ristvey, Mary Lorscheider, Sarah Dickinson, and John M. Ruter

Increasing environmental concerns and legislation in many states and in other countries require that we take a more comprehensive sustainable “best management” approach to production techniques in nursery and greenhouse operations. This is particularly important because these production facilities are typically intense users of resources that are applied to relatively small land areas. We have developed an online knowledge center to facilitate the implementation of more sustainable practices within the nursery and greenhouse industry. A web-based knowledge center provides the most cost-effective mechanism for information delivery, as our potential audiences are extremely diverse and widespread. We currently have a registered user database of over 450 educators, growers, and industry professionals, and undergraduate and graduate students. A gateway website provides an overview of the issues and the goals of the project. The associated knowledge center currently has 25 in-depth learning modules, designed in a Moodle learning management framework. These learning modules are designed to actively engage learners in topics on substrate, irrigation, surface water, and nutrient and crop health management, which are integral to formulating farm-specific strategies for more sustainable water and nutrient management practices. Additional modules provide assessment and implementation tools for irrigation audits, irrigation methods and technologies, and water and nutrient management planning. The instructional design of the learning modules was paramount because there can be multiple strategies to improve site-specific production practices, which often require an integration of knowledge from engineering, plant science, and plant pathology disciplines. The assessment and review of current practices, and the decision to change a practice, are often not linear, nor simple. All modules were designed with this process in mind, and include numerous resources [pictures, diagrams, case studies, and assessment tools (e.g., spreadsheets and example calculations)] to enable the learner to fully understand all of the options available and to think critically about his/her decisions. Sixteen of the modules were used to teach an intensive 400-level “Principles of Water and Nutrient Management” course at the University of Maryland during Spring 2008 and 2009. The water and nutrient management planning module also supports the nursery and greenhouse Farmer Training Certification program in Maryland. The Maryland Department of Agriculture provides continuing education credits for all consultants and growers who register and complete any module in the knowledge center. Although these learning resources were developed by faculty in the eastern region of the United States, much of the information is applicable to more widespread audiences.

Full access

Joyce G. Latimer, Reuben B. Beverly, Carol D. Robacker, Orville M. Lindstrom, S. Kristine Braman, Ronald D. Oetting, Denise L. Olson, Paul A. Thomas, Jerry T. Walker, Beverly Sparks, John M. Ruter, Wojciech Florkowski, Melvin P. Garber, and William G. Hudson

Optimizing growing conditions and, thereby, plant growth reduces the susceptibility of plants to many disease and insect pest problems. Educating lawn or landscape management professionals and homeowners about plant health management reduces the need for chemical intervention. Pesticides combined with N and P fertilizers contribute to water pollution problems in urban areas; thus, it is important to manage the amount, timing, and placement of chemicals and fertilizers. To educate consumers applying pesticides and fertilizers in residential gardens, we must educate the sales representatives and others who interact most closely with consumers. Evidence suggests that knowledge about the effects of chemicals is limited and that warning labels are not read or are ignored. Integrated pest management (IPM) offers alternatives to conventional chemical treatments, but such methods are not used commonly because of their relatively high cost and their uncertain impact on pests. Pest detection methods and using pest-resistant plants in landscapes are simple and, in many cases, readily available approaches to reducing the dependence on chemical use. Research on effective, low-cost IPM methods is essential if chemical use in landscape management is to decrease. Current impediments to reducing the pollution potential of chemicals used in the landscape include the limited number of easily implemented, reliable, and cost-effective alternative pest control methods; underfunding of research on development of alternative pest control measures; limited knowledge of commercial operators, chemical and nursery sales representatives, landscape architects, and the general public concerning available alternatives; reluctance of the nursery industry to produce, and of the landscape architects to specify the use of, pest-resistant plant materials; lack of economic or regulatory incentive for professionals to implement alternatives; inadequate funding for education on the benefits of decreased chemical use; and the necessity of changing consumer definition of unacceptable plant damage. We need to teach homeowners and professionals how to manage irrigation to optimize plant growth; use sound IPM practices for reducing disease, weed, and insect problems; and minimize pollution hazards from fertilizers and pesticides.

Full access

Joyce G. Latimer, Reuben B. Beverly, Carol D. Robacker, Orville M. Lindstrom, Ronald D. Oetting, Denise L. Olson, S. Kristine Braman, Paul A. Thomas, John R. Allison, Wojciech Florkowski, John M. Ruter, Jerry T. Walker, Melvin P. Garber, and William G. Hudson

Pesticides have been the primary method of pest control for years, and growers depend on them to control insect and disease-causing pests effectively and economically. However, opportunities for reducing the potential pollution arising from the use of pesticides and fertilizers in environmental horticulture are excellent. Greenhouse, nursery, and sod producers are using many of the scouting and cultural practices recommended for reducing the outbreak potential and severity of disease and insect problems. Growers are receptive to alternatives to conventional pesticides, and many already use biorational insecticides. Future research should focus on increasing the effectiveness and availability of these alternatives. Optimizing growing conditions, and thereby plant health, reduces the susceptibility of plants to many disease and insect pest problems. Impediments to reducing the use of conventional pesticides and fertilizers in the environmental horticulture industry include 1) lack of easily implemented, reliable, and cost-effective alternative pest control methods; 2) inadequate funding for research to develop alternatives; 3) lack of sufficient educational or resource information for users on the availability of alternatives; 4) insufficient funding for educating users on implementing alternatives; 5) lack of economic or regulatory incentive for growers to implement alternatives; and 6) limited consumer acceptance of aesthetic damage to plants. Research and broadly defined educational efforts will help alleviate these impediments to reducing potential pollution by the environmental horticulture industry.