bluuebunny/crossref_metadata_2025 huggingface dataset:
Season and Genotype Influence Golf Ball Roll Distance on Creeping Bentgrass
Authors: Rist A.M. , Gaussoin R.E. , Shearman R.C. , Fry J.D. , Stroup W.W.
Published: February 2019

Golfers are demanding increased ball roll distances on a daily basis, but cultural practices to achieve this often are detrimental to the green. One option for increasing ball roll distance without altering cultural practices may be to select creeping bentgrass genotypes that provide less resistance to ball roll. Studies were conducted at the John Seaton Anderson Turfgrass and Ornamental Research Facility near Ithaca, Neb., and at the Rocky Ford Turfgrass Research Facility in Manhattan, Kans., to determine genotype and seasonal influences on golf ball roll distance. Eighteen creeping bentgrass (Agrostis palustris Huds.) genotypes were evaluated. Genotype was not a significant source of variability, but the location × season interaction was. Significant seasonal differences in ball roll occurred at both locations. Ball roll distances for spring, summer, and fall were 98, 15, and 31 cm greater at the Nebraska test location than at the Kansas site. Correlations between turfgrass visual quality and ball roll distance were not significant. Therefore, the use of genotypes exhibiting high turfgrass visual quality will not necessarily result in longer ball rolls. Since there were no season × genotype or genotype × location interactions, ball roll distance on genotypes at each location changed similarly with season. Genotype selection appears to have little influence on ball roll distance under the conditions tested at these two locations.
Root-knot Nematode Resistance in Cucumis Species
Authors: Nugent Perry E. , Dukes P.D.
Published: February 2019

The southern root-knot nematode, Meloidogyne incognita [(Kofoid & White) Chitwood], causes serious economic losses to melon (Cucumis melo L.) production in the United States. The present study was conducted to determine if separable differences in nematode resistance of Cucumis melo could be found at some inoculum level. Five C. melo lines were compared with Cucumis metuliferus Naud. (C701A), a highly resistant species, for root necrosis, galling, egg mass production, and reproduction when inoculated at 0, 500, 1000, 2000, or 5000 nematode eggs per plant. Using these criteria, melon line C880 inoculated with 1000 eggs per plant was highly susceptible, while PI140471, PI 183311, and the cultivars Chilton, Georgia 47, Gulf Coast, Planters Jumbo, and Southland were less susceptible. In greenhouse tests with an inoculum level of 1000 eggs per plant, low levels of resistance were evident. A thorough screening of the available germplasm against M. incognita may identify higher levels of root-knot nematode resistance for incorporation into improved melon cultivars.
Eating Quality of `Gala' and `Fuji' Apples from Multiple Harvests and Storage Durations
Authors: Plotto Anne , Azarenko Anita N. , McDaniel Mina R. , Crockett Patrick W. , Mattheis James P.
Published: February 2019

Eating quality of `Gala' and `Fuji' apples (Malus domestica Borkh.) from multiple harvests and storage durations was assessed using an untrained consumer panel. Apples were harvested at weekly intervals for 6 weeks and stored in air. Changes due to harvest maturity and storage for overall liking (OL), sweetness, tartness, firmness, and flavor intensity were evaluated over 8 months. A multivariate factor analysis revealed multicollinearity for OL, sweetness, and flavor intensity ratings in both cultivars. These attributes had the highest loadings in the first factor, explaining 51% and 52% of the variance of `Gala' and `Fuji' data sets, respectively, and were interpreted as a quality factor. Tartness and firmness had the highest loadings in the second factor for `Gala', explaining an additional 23% of the variability and reducing that cultivar's data set to two factors. For `Fuji', however, tartness and firmness were independent and included in factors 2 and 3, respectively. Factors 2 and 3 were interpreted as maturity factors, which explained 23% and 12% of the variance. The plots of the mean factor scores provided a multivariate technique to illustrate that panelists could differentiate between the stages of maturity of apples. Canonical correlations were calculated between the sensory and instrumental data. Only firmness measurements were correlated with sensory ratings for firmness (r = 0.53 and 0.44 for `Gala' and `Fuji', respectively).
Fruit Maturity and Calcium Affect Chilling Requirements and Ripening of `d'Anjou' Pears
Authors: Gerasopoulos D. , Richardson D.G.
Published: February 2019

`D'Anjou' pear (Pyrus communis L.) trees were sprayed with zero or 32.3 mm CaCl2 during fruit development at 55, 86, 125, and 137 d from full bloom and harvested at 85% (immature), 100% (mature), and 110% (overmature) maturity stages. The fruit were stored in air at –1 °C for several periods to determine the effect of CaCl2 treatments on chilling requirement to accomplish ripening during 11 d at 20 °C. Immature or mature unsprayed fruit required 55 d, while the overmature fruit required 40 d at –1 °C to gain the capacity to produce ethylene during ripening at 20 °C. Calcium sprays increased flesh firmness at harvest by 15 N, fruit Ca concentrations by an average of 0.01 mg·g-1, fresh mass basis, and the chilling requirements by at least 15 d. Unsprayed immature fruit contained more Ca than the sprayed mature or overmature fruit, but their chilling requirement was similar. These results suggest that high Ca concentrations may increase the chilling requirement of `d'Anjou' pears in a developmentally related manner.
Evaluation of Capsicum chinense Jacq. Cultigens for Resistance to the Southern Root-knot Nematode
Authors: Fery Richard L. , Thies Judy A.
Published: February 2019

Scotch Bonnet and Habanero peppers, extremely pungent cultivar classes of Capsicum chinense Jacq., are increasing in popularity in the United States. Because the southern root-knot nematode, Meloidogyne incognita (Kofoid & White) Chitwood, is a major pest of many C. annuum cultivars, a series of greenhouse and field experiments was conducted to determine if Scotch Bonnet and Habanero peppers from available commercial and private sources also are vulnerable to the pest. In an initial greenhouse test, a collection of 59 C. chinense cultigens was evaluated for reaction to M. incognita race 3. All cultigens obtained from commercial sources were moderately susceptible or susceptible. However, four accessions obtained through Seed Savers Exchange listings exhibited high levels of resistance. Three of these cultigens (PA-353, PA-398, and PA-426) were studied in subsequent greenhouse and field plantings, and each was confirmed to have a level of resistance similar to that available in C. annuum. All three of the resistant cultigens are well-adapted and each is potentially useful in commercial production without further development. None of the Habanero cultigens was resistant to the southern root-knot nematode. The resistant Scotch Bonnet cultigens may serve as sources of resistance for development of root-knot nematode—resistant Habanero peppers.
A Versatile and High-yielding Protocol for the Preparation of Genomic DNA from Capsicum spp. (Pepper)
Authors: Prince J.P. , Zhang Y. , Radwanski E.R. , Kyle M.M.
Published: February 2019

The isolation of genomic DNA from Capsicum spp. (pepper) of the quality and quantity required for analyses based on nucleic acid hybridization and/or the polymerase chain reaction (PCR) has proven difficult. We report here a procedure that reliably yields sufficient quantities of good-quality pepper genomic DNA from a variety of Capsicum genotypes.
Preplant Cover Crops Affect Weed and Vine Growth in First-year Vineyards
Authors: Bordelon Bruce P. , Weller Stephen C.
Published: February 2019

Use of in-row cover crops for weed management in first-year vineyards was investigated in two studies. In the first study, rye (Secale cereal L. 'Wheeler') was fall-planted, overwintered, then managed by three methods before vine planting. Rye was either herbicide-desiccated with glyphosate and left on the surface as a mulch, mowed, or incorporated into the soil (cultivated). Weed density and growth of grapevines (Vitis spp.) were evaluated. Herbicide desiccation was superior to the other methods for weed suppression, with weed densities 3 to 8 times lower than for mowed or cultivated plots. Vine growth was similar among treatments, but the trend was for more shoot growth with lower weed density. In a second study, four cover crops, rye, wheat (Triticum aestivum L. 'Cardinal'), oats (Avena sativa L. 'Ogle'), and hairy vetch (Vicia villosa Roth), were compared. Wheat and rye were fall- and spring-planted, and oats and vetch were spring-planted, then desiccated with herbicides (glyphosate or sethoxydim) after vine planting and compared to weed-free and weedy control plots for weed suppression and grapevine growth. Cover crops provided 27% to 95% reduction in weed biomass compared to weedy control plots. Total vine dry mass was highest in weed-free control plots, was reduced 54% to 77% in the cover crop plots, and was reduced 81% in the weedy control. Fall-planted wheat and rye and spring-planted rye plots produced the highest vine dry mass among cover crop treatments. Spring-planted rye provided the best combination of weed suppression and vine growth. Chemical names used: N-(phosphonomethyl) glycine (glyphosate isopropylamine salt); 2-[l-(ethoxyimino)butyl]5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one (sethoxydim).
Morphological Plasticity of Dracaena sanderana `Ribbon' in Response to Four Light Intensities
Authors: Vladimirova Svoboda V. , McConnell Dennis B. , Kane Michael E. , Henley Richard W.
Published: February 2019

Effects of four shade levels on the growth of Dracaena sanderana hort Sander ex Mast. `Ribbon' were evaluated. The experiment was conducted using model structures providing four shade levels (47%, 63%, 80%, and 91%). Dracaena sanderana exhibited morphological plasticity in growth and development. Under 63% and 80% shade, plants grew faster and achieved greater biomass than those grown in 47% and 91 % shade. The lowest (47%) and the highest shade (91 %) provided supraoptimal and suboptimal light levels, respectively. More leaves with less leaf area, larger internodes, and larger root mass developed in plants grown in 63% shade. Fewer leaves with larger leaf areas, smaller internodes, and smaller root mass developed in plants grown in 80% shade. Plants grown in 47% or 63% shade were less variegated than those grown in 80% or 91 % shade. Maximum leaf variegation occurred under 91 % shade.
Chlorothalonil Fungicides Reduce Vase Life but not Yield of Leatherleaf Fern [Rumohra adiantiformis (Forst.) Ching]
Authors: Stamps Robert H. , McColley Daniel W.
Published: February 2019

Established ground beds of leatherleaf fern were sprayed repeatedly with water, a flowable formulation of thiophanate-methyl, or one of four formulations of chlorothalonil on a predominantly weekly schedule. None of the treatments produced visible phytotoxicity symptoms or had any effect on yield (frond number and total fresh mass). However, average masses of fronds from plots treated with a liquid formulation of chlorothalonil were 21% greater than those from control plots. All chlorothalonil formulations left visible residues on the fronds and reduced frond vase life compared to fronds treated with water or thiophanate-methyl. Reduced vase life was due to more rapid desiccation of chlorothalonil-treated fronds. During those months (July—Sept.) when postharvest desiccation is most common, chlorothalonil reduced vase life of fronds by 36% to 62%. Vase life of fronds was generally reduced more by dry chlorothalonil formulations than by liquid ones, probably due to slightly higher application rates of dry formulations. Determination of the mode of action could lead to an understanding of the causes of frond curl syndrome. Until a remedy is found, chlorothalonil should not be used repeatedly on leatherleaf fern. Chemical names used: tetrachlorisophthalonitrile (chlorothalonil); dimethyl [(1,2-phenylene)-bis(iminocarbonothioyl)]bis[carbamate]) (thiophanate-methyl).
Interactions of Irradiance Level and Iron Chelate Source During Shoot Tip Culture of Carica papaya L.
Authors: Castillo B. , Smith M.A.L. , Madhavi D.L. , Yadava U.L.
Published: February 2019

Interactions between irradiance levels (5–40 μmol·m-2·s-1) and iron chelate sources (FeEDTA and FeEDDHA) were observed for Carica papaya shoot tip cultures during both the establishment and proliferation stages of microculture. Reduced levels of irradiance (5 μmol·m-2·s-1) favored shoot tip establishment regardless of the source or level of iron. However, the highest percentage of successful explant establishment (100%), and significantly greater leaf length (1.16 cm; over double the size attained in any other treatment), resulted when a low concentration of FeEDTA alone was used at low irradiance. During the subsequent shoot proliferation stage, however, higher irradiance levels (30 and 40 μmol·m-2·s-1) were required, and FeEDTA failed to support culture growth when used as the sole iron source. The highest multiplication rates (3.6 shoots per explant) and leaf chlorophyll concentrations (0.22 mg/g fresh mass), and significantly improved shoot quality were achieved at 30 μmol·m-2·s-1 irradiance when both iron chelate formulations were combined (each at a 100 μM concentration) in the proliferation medium. Chemical names used: benzylamino purine (BA); ferric disodium ethylenediamine tetraacetate or FeNa2EDTA (FeEDTA); ferric monosodium ethylenediamine di(o-hydroxyphenylacetate), (FeNaEDDHA) or Sequestrene 138Fe (FeEDDHA); indoleacetic acid (IAA); 1-naphthaleneacetic acid (NAA).
Micropropagation of Centaurea macrocephala Pushk. ex Willd. by Shoot-axis Splitting
Authors: Hosoki Takashi , Kimura Daisuke
Published: February 2019

Micropropagation of Centaurea macrocephala Pushk. ex Willd. was achieved by subculturing of vertically split shoots and division of axillary buds on MS-based medium with 0.44 μm BA. A proliferation rate of 2.0 per 16-day culture period was obtained. Seventy percent of microcuttings obtained through in vitro culture could be rooted on a modified Hyponex medium with 25 μM IBA. All plantlets were readily acclimatized and grown in a greenhouse. Chemical names used: benzylaminopurine (BA); indole-3-butyric acid (IBA).
Assessing the Economic Efficiency of a Soilless Culture System for Off-season Strawberry Production
Authors: Mattas K. , Bentes M. , Paroussi G. , Tzouramani I.
Published: February 2019

The financial effectiveness of a soilless vertical bag system of hydroponics culture was evaluated for off-season strawberry (Fragaria ×ananassa Duch) production in heated greenhouses in northern Greece. Financial analysis revealed that the implementation of this soilless culture system instead of the traditional production system under plastic tunnels would not be profitable for Greek farmers due to its high initial investment and high fuel consumption. Sensitivity analysis indicated the importance of product price in affecting the magnitude of benefits, confirming the interest of farmers to produce off-season strawberries to market them when prices are likely to be higher. In addition, yield increase will have a positive effect upon farmers' income.
The Internet Forces the Scientific Community to Face its Ethical Problems
Authors: Pollock Bruce M.
Published: February 2019

Historically, ethical issues in science have disappeared behind the veil which alleges that science is self-correcting because of its reliance on secret peer review. Unfortunately, that same peer review process has closed scientific journals to scientists holding to different ethical standards, while access to the law and courts has been a prohibitively expensive mechanism to protest unethical actions. Although eager to sensationalize ethical lapses, news media have been ineffective in correcting the problems. As a result, dissension has been left exclusively to lay activists. Against this background, in the 1995 AIBS symposium, “Ethics, Science, and Public Policy,” Bella described scientific publications as “propaganda” and Mattson discussed the fact that unbiased science cannot exist within government agencies. However, with the sudden rise of the World Wide Web, scientific societies have lost control of publication, and legal confidentiality has disappeared, because the Web now provides outlets for dissenting views and the opportunity to bring corruption in science to public attention. Thus placed under public scrutiny, the scientific community must confront an urgent need to examine its ethical standards.
Source of Pollen, Distance from Pollinizer, and Time of Pollination Affect Yields in Block-type Pecan Orchards
Authors: Wood Bruce W.
Published: February 2019

Inadequate cross-pollination of pecan [Carya illinoinensis (Wangenh.) K. Koch] occurred in block-type orchards generally thought exempt from pollination-related crop losses because of an abundance of nearby potential pollinizers. “Off-genotypes” appeared to be potentially major assets in such orchards due to their role as backup pollinizers; hence, their presence insures against crop losses due to poor pollination. Fruit-set in `Desirable' main crop rows declined sigmoidally as distance from 'Stuart' pollinizer rows increased. For 15.4-m row spacings, rate of decrease was maximum between 49 and 78 m, depending on crop year. Maximum fruit-set was in rows immediately adjacent to the pollinizer. Tree age/size and spring temperature influences on the characteristics of flower maturity windows are probably primary factors contributing to pollination-related fruit-set losses in block-type orchards relying upon pollen from a single complementary pollinizer or from neighborhood trees. For example, flower maturity was earlier in older/larger trees, and higher spring temperatures accelerated catkin development relative to that of pistillate flowers. Maximum fruit-set occurred when pistillate flowers received pollen around 1 day or less after becoming receptive, whereas no fruit-set occurred when they were pollinated around four or more days after initial receptivity. These findings indicate that many block-type orchards in the southeastern United States are exhibiting pollination-related crop reductions and that future establishment of such orchards merits caution regarding the spatial and temporal distribution of pollinizers.
RAPD Markers from Perennial Ryegrass DNA Extracted from Seeds
Authors: Sweeney Patricia M. , Danneberger T. Karl
Published: February 2019

As the number of perennial ryegrass (Lolium perenne L.) cultivars increases, the development of reliable identification methods becomes more important. Randomly amplified polymorphic DNA (RAPD) markers show promise in cultivar identification. Since perennial ryegrass cultivars are composites of genotypes rather than a single genotype, finding markers that distinguish cultivars is difficult. The ideal cultivar identification procedure would use seed tissue as a DNA source and evaluate a single sample as representative of a cultivar. The objective of this research was to determine whether RAPD markers could be used to consistently distinguish bulk seed samples of perennial ryegrass cultivars. Two extraction protocols were evaluated. A quick, simple extraction resulted in the amplification of few consistent RAPD markers. The more labor-intensive extraction with hexadecyltrimethyl ammonium bromide (CTAB), however, produced more reliable RAPD markers. Eight of 11 cultivars were distinguished by using RAPD markers produced using bulk seed samples together with four of 30 primers that were screened. These results show the potential of RAPD markers to provide the turfgrass industry, breeders, and certification agencies additional options to ensure the genetic integrity of perennial ryegrass seed lots and cultivars.
Effect of Pesticide-treated Grass Clippings Used as a Mulch on Ornamental Plants
Authors: Branham B.E. , Lickfeldt D.W.
Published: February 2019

With increasing pressure to reduce disposal of yard waste in landfills, many homeowners are seeking alternative methods for grass clipping disposal. When turf is treated with pesticides, the collected grass clippings become a potential source of injury to susceptible plants that come in contact with the clippings. In this study, grass clippings were collected at 2, 7, and 14 days after pesticide treatment from a turf treated with chlorpyrifos, clopyralid, 2,4-D, flurprimidol, isoxaben, or triclopyr. The clippings were used as a mulch around Lycopersicon esculentum Mill. (tomato), Phaseolus vulgaris L. (bush bean), Petunia ×hybrida Hort. Vilm.-Andr. (petunia), and Impatiens wallerana Hook. f. (impatiens). Beans were planted 4 weeks prior to mulching, whereas the other plants were grown in the greenhouse for 6 weeks and transplanted into the field 2 weeks prior to mulching. Clippings containing residues of clopyralid, 2,4-D, or triclopyr killed tomato, bean, and petunia plants when used 2 days after pesticide treatment (DAPT) and severely injured these same species when mulched 7 and 14 DAPT. Flurprimidol injured tomato, impatiens, and bean plants when present on mulch collected 2, 7, and 14 DAPT, but was not lethal. Flurprimidol slowed plant growth, caused darker green leaf color, and reduced flowering when mulched at 2 DAPT. Isoxaben injured tomato and bean plants when present on mulch used 2, 7, and 14 DAPT but was not lethal. Injury was not as severe in the second year of the study, indicating different environmental stresses and climatic conditions make predicting pesticide injury for all growing seasons difficult; however, grass clippings from a turf treated with herbicides or plant growth regulators should not be used for mulch around sensitive plants for at least 14 DAPT. Chemical names used: 0,0-diethyl O-(3,5,6-trichloro-2-pyridinyl) phosphorothioate (chlorpyrifos); 3,6-dichloro-2-pyridinecarboxylic acid, triethylamine salt (clopyralid); 2,4-dichlorophenoxyacetic acid, dimethylamine salt (2,4-D); α-(1-methylethyl)-α-[4-(trifluromethoxy)phenyl]-5-pyrimidinemethanol (flurprimidol); N-[3-(1-ethyl-1-methylpropyl)-5-isoxazolyl]-2,6-dimethoxybenzamide and isomers (isoxaben); 3,5,6-trichloro-2-pyridinyloxy acetic acid, triethylamine salt (triclopyr).
Cryptococcus humicola Inhibits Development of Lesions in `Golden Delicious' Apples
Authors: Anderson Jeffrey A. , Filonow Alexander B. , Vishniac Helen S.
Published: February 2019

One strategy to reduce postharvest losses of fruits to pathogens is to introduce organisms with biological control capabilities. Our objective was to determine the effectiveness of two yeast isolates in inhibiting lesion development caused by Botrytis cinerea (Bc) on freshly harvested apples differing in maturity. `Golden Delicious' apples were harvested on 29 Aug., 23 Sept., and 10 Oct. 1995. Apples receiving the seven treatments [control, wound, Cryptococcus humicola (Ch), Sporobolomyces roseus (Sr), Bc, Ch + Bc, Sr + Bc] were placed in plastic boxes with damp paper towels. Each day for 7 days, ethylene production and lesion diameter at the wound were recorded. Ethylene production was not affected by treatment, and increased with later harvest date. Lesion diameter on apples treated with Bc was smaller on the first harvest than on the second and third harvests. Sr provided partial control on the second and third harvests, and Ch completely inhibited lesion development except for day 7 of the third harvest.
Enzyme Polymorphism in Cymbidium Orchid Cultivars and Inheritance of Leucine Aminopeptidase
Authors: Obara-Okeyo P. , Fujii Kouei , Kako Shunji
Published: February 2019

Seventy Cymbidium (Swartz.) cultivars were analyzed for isozyme variability in eight enzyme systems by starch gel electrophoresis. All systems studied [aspartate aminotransferase (AAT), malate dehydrogenase (MDH), alcohol dehydrogenase (ADH), phosphoglucomutase (PGM), glucose phosphate isomerase (GPI), triosephosphate isomerase (TPI), and shikimate dehydrogenase (SKDH)] showed polymorphism. When all enzyme systems were evaluated, 68 of the 70 Cymbidium cultivars could be distinguished. Isozymes could not distinguish betwen the cultivars Golden Star `Kumamoto' and Golden Star `Sunrise'. No cultivar showed a single unique pattern, but the TPI system gave one “diagnostic” pattern. Segregation ratios from controlled crosses suggested that LAP-1 is simply inherited and controlled by at least two alleles.
Effect of Water Bath Temperature and Stratification on Germination of Pecan Seed
Authors: Smith Michael W. , Cheary Becky S. , Carroll Becky L.
Published: February 2019

Parameters were defined to germinate pecan [Carya illinoinensis (Wangenh.) C. Koch] seeds in aerated water followed by container planting. Germination was not affected by the ratio of seeds to water in the germination containers. Highest germination rates with the greatest uniformity in germination were obtained with a water bath temperature of 32 °C. Stratification up to 188 days increased the rate of germination, but the largest response was between no stratification and 56 days (6.5 days vs. 2.3 days to reach 50% germination, respectively). Seeds that were germinated in a water bath, then planted in containers, achieved 50% emergence in 4.7 days compared to 12.4 days for direct-planted seed. Emergence was more uniform when seeds were germinated in water before planting compared with seeds that were directly planted in containers (7.0 days vs. 9.5 days between 10% and 90% emergence, respectively). Also, by germinating the seeds before planting, nonviable seeds were eliminated, resulting in 100% emergence compared to 76% emergence when planted directly.
Micropropagation of Satureja obovata Lag.
Authors: Arrebola M.L. , Socorro O. , Barceló-Muñoz A. , Simón-Pérez E. , Pliego-Alfaro Fernando
Published: February 2019

A micropropagation procedure for juvenile and adult savory (Satureja obovata Lag.) explants is described. Pretreatment of the nutlets with gibberellic acid (0.57 mm) did not improve in vitro germination. Optimum shoot proliferation of juvenile and adult material was obtained on medium containing 2.22 μm N6-benzyladenine. Rooting and acclimatization of juvenile shoots were accomplished in vivo, while adult shoots were rooted in vitro after 3 days of exposure to 4.92 μm indole-3-butyric acid followed by subsequent transfer to auxin-free medium. More than 95% survival of adult rooted plants was obtained during the acclimatization phase. Chemical names used: gibberellic acid (GA3); N6-benzyladenine (BA); indole-3-butyric acid (IBA); isopentenyladenine (2iP).
Broadleaf Weed Control in Field-grown Herbaceous Perennials
Authors: Pennuci Annamarie
Published: February 2019

Novel and standard herbicides were applied alone, sequentially, or tank-mixed to determine weed control efficacies and tolerances in 15 species of field-grown herbaceous perennials. Autumn applications provided excellent but short-term broadleaf (BL) and annual grass (AG) weed control. Early spring applications were equally effective and of longer duration. Mid- and late spring treatments provided moderate to poor control of AG and poor control of winter perennial BL. Single applications of prodiamine provided season-long control of AG and of spring germinating BL. Greatest number of weed species were controlled by DCPA. Increased duration occurred with tank-mixes of DCPA + pendlimethalin, DCPA + quinclorac. Quinclorac provided excellent pre/post control of AG and some BL. Crop injury was minimized with directed applications. Isoxaben provided excellent preemergent control of BL. Tank-mixes improved AG control. Treatments applied prior to, or at the same time as mulch applications increased weed control and lessened drought stress. Treatments applied over mulch were less effective, suppressed fewer weed species, were of shortened duration, and increased the likelihood of crop injury.
Zinc, Manganese, and Iron Fertilization in `Spineless Beauty' Zucchini (Cucurbita sp.)
Authors: Morales-Payan J. Pablo
Published: February 2019

Zucchini (Cucurbita sp.) fruit yield response to zinc (Zn), manganese (Mn), and iron (Fe) foliar fertilization was determined in field trials conducted in a loamy clay soil in Nigua, San Cristobal, Dominican Republic. The soil had Zn, Mn, and Fe contents of 1.2, 8, and 2 parts per million (ppm), respectively. `Spineless Beauty' zucchini was direct-seeded at a distance of 1 m between rows and 0.5 m within rows. Except for Zn, Mn, and Fe fertilization, the crop was grown according to recommended practices. Experimental units contained five plants. A randomized complete-block design with a factorial arrangement (3 × 3 × 3) with four replications was utilized. Micronutrient rates were 0, 1, and 3 kg·ha–1 for Zn; 0, 3, and 6 kg·ha–1 for Mn; and 0, 3, and 6 kg·ha–1 for Fe. Total rates were divided in two 50% rate applications, sprayed in aqueous solution to the crop leaves 15 and 30 days after emergence. Fruit harvest began 40 days after crop emergence and was performed every other day during 20 days. Resulting data was subjected to analysis of variance. There were significant Zn, Mn, and Fe interactions, and thus micronutrient combinations were considered as individual treatments. Treatment means were separated with the lsd 5% test. Zucchini plants treated with a combination of 3 kg Zn/ha, 3 kg Mn/ha, and 3 kg Fe/ha produced fruit yields 31.5% higher than control plants. Combinations including higher Mn and Fe rates failed to further increase zucchini yields.
Undergraduate Program Growth and Enhancement: The Results of Curriculum Assessment in Landscape Contracting
Authors: McGann Martin R. , Stearns Dan T. , Kuhns Larry J.
Published: February 2019

Following a recent curriculum assessment effort involving faculty, students, and industry representatives, the Dept. of Horticulture at Penn State developed a strategic action plan for future growth and evolution of its landscape contracting program. Highlights of the plan include: establishment of a landscape management option with emphasis on weed, pest, and disease management, plant establishment and plant maintenance; refinement of an internship program; continuation of collaborative and experiential learning opportunities; and development of a course that addresses current issues in the landscape profession. Additional actions resulting from the assessment process range from the addition of a Spanish course to support for the establishment of a campus arboretum.
Effects of Sucrose and Oxygen on Nitrate Reductase Activity and Growth of Kentucky Bluegrass
Authors: Jiang Zhongchun , Hull Richard J.
Published: February 2019

Nitrate reductase activity (NRA) in turfgrass roots should play an important role in the N metabolism of the whole plant because a major part of the shoots is removed by mowing. However, preliminary experiments demonstrated a lack of in vivo NRA in roots of Kentucky bluegrass grown in Hoagland's nutrient solutions, which were constantly aerated. We hypothesized that O2 inhibited NRA by oxidizing carbohydrate available for NO3– reduction in roots. To test this hypothesis, Kentucky bluegrass (Poa pratensis L.), cultivar Merit, was grown in nutrient solutions containing 0.1 mM NO3–. Grass cultures were treated with +O2 (solution aerated), –O2 (not aerated), +Suc (sucrose added to solution, final concentration = 25 mM) or –Suc (not added) for 12 days. Plants were harvested at 5:00 pm, separated into shoots and roots, and analyzed for in vivo NRA. The results partly supported the above hypothesis because the –Suc–O2 roots showed significantly higher NRA than –Suc+O2 roots. However, +Suc roots did not exhibit greater NRA than –Suc roots, possibly because of a decreased pH in the solutions. Oxygen increased root growth and hence the growth of the whole plant, while sucrose decreased leaf N content and leaf NRA but did not improve growth.
Genetic Relationships among Cultivated Species of Rhododendron L. Section Pentanthera G.Don Based on DNA Sequence Variation of the Internal Transcribed Spacer (ITS) Region
Authors: Scheiber S.M. , Jarret R.L. , Robacker C.D.
Published: February 2019

Rhododendron section Pentanthera has traditionally been viewed as a group of closely related species due to the relative lack of distinctive morphological characteristics separating species and numerous reports in the literature of artificial and natural fertile hybrids that produce fertile progeny. Significant variation within species has created difficulties in efforts to assemble these taxa into well-defined groups. Genetic relationships among cultivated specimens of the 15 currently recognized species in Rhododendron section Pentanthera were derived from sequence comparisons of the internal transcribed spacer (ITS) region. Sequences of the entire ITS region including ITS1, ITS2, and the 5.8S subunit were generated by direct sequencing of polymerase chain reaction (PCR) amplified fragments. Rhododendron vaseyi A.Gray, Rhododendron section Rhodora (L.) G.Don was used as an outgroup. Aligned sequences of the 16 taxa resulted in 690 characters. A distance matrix of sequence divergence was calculated using Kimura's two parameter model. A bootstrap analysis was performed and a phenogram was constructed using MEGA. A phenetic assay rather than a phylogenetic analysis was performed because the ITS region contained only eight (1.16%) phylogenetically informative sites. The entire ITS region contained 41 variable sites (5.94%). Five species had identical ITS sequences. Seven additional species differed only by one or two base pair substitutions and/or the addition or deletion of one or two base pairs. R. luteum Sweet, R. occidentale A. Gray, R. molle (Blume) G.Don, and the outgroup, R. vaseyi had noticeable variation (base substitutions, additions, and deletions) compared to the other species. Divergence values among the taxa were extremely low, ranging from 0.00% to 3.51%. This molecular data, and previous hybridization studies, do not support the accepted taxonomic treatment of the section.
Unknown Cultivars of Cold-hardy Grape Can Be Successfully Identified by Their Simples Sequence Repeat (SSR) Fingerprints
Authors: Lamboy Warren F. , Alpha Christopher A. , Peterson David V.
Published: February 2019

Simple sequence repeat DNA fragments (SSRs) have been suggested as the method of choice for DNA fingerprinting of grape cultivars. Nevertheless, the use of SSRs as a practical fingerprinting method is not without its pitfalls. For example, when the polymerase chain reaction is used to amplify SSR sequences, potentially confusing “stutter” bands may occur, or there may be non-template directed addition of an “A” to the end of synthesized fragments, or other artifactual amplification products may be produced. Since we would like to fingerprint our entire cold-hardy grape collection of ≈1300 cultivars, we decided to conduct a blind test to determine if SSR fingerprinting actually would be practical in our circumstances. First, SSR fingerprints were established for 45 commercially important cool-climate grape cultivars, the known standards. Then, SSR fingerprints were produced for 44 “unknown” cultivars grown in the Finger Lakes Region of New York. The identities of these were known only to the third author. To independently identity these “unknowns,” their fingerprints were compared to those of the known standards. By this means, 42 of the 44 “unknowns” were immediately correctly identified. The identity of one of the two remaining unknowns was truly not known to the vineyard owner; it was identified as Cabernet Franc, a grape commonly grown in the region. The final “unknown” was a plant of Pinot Blanc, whose fingerprint matched those of both the known and the unknown Pinot Gris and Pinot Noir plants, but did not match that of the Pinot Blanc plants used as standards. This was surprising, since all three Pinot's varieties are simply fruit color mutants of the same genotype. Further investigation revealed that the known plants of “Pinot Blanc” had been misidentified, and actually were the cultivar Melon. Thus, identification of the “unknown” Pinot Blanc as Pinot Noir or Pinot Gris was correct, as were the identifications of the 43 other `unknowns.”

This study confirmed that SSR fingerprinting is a practical method for identifying cool-climate grape cultivars.
Tomato Production on Sand with Polyethylene Mulch, Microirrigation, and Using Banded Compost as Soil Amendment
Authors: Csizinszky A.A.
Published: February 2019

Tomatoes, cv. Agriset 761, were grown in Spring and Fall 1996 at three compost rates, 0x, 1x and 2x (1x = 12 t·ha-1). Production system was the full-bed polyethylene mulch with micro- (trickle-) irrigation. The crop in each treatment received (kg·ha-1) 73 N, 34 P, and 121 K from preplant dry, and 225 N and 372 K from injected liquid fertilizers in 117 days during the spring and in 107 days in the fall. Plant growth (plant height) was best with the lx compost rate. Fruits were harvested five times in the spring and four times in the fall. Compost amendments in both seasons delayed fruit maturity. In the spring, marketable yields in the first two harvests were higher (P < 0.05) without than with compost. For the season, marketable yields (t·ha-1) were 57 with 0x, 71 with 1x, and 77 with 2x compost rate (P < 0.001). In the fall, yield differences were smaller or nonsignificant among the treatments and marketable yields for the season were highest with the 1x compost rate.
Regional Vegetable Variety Trials: Myth or Reality?
Authors: Simonne Eric , Shumack Ronald
Published: February 2019

Vegetable variety trials (VVT) are of interest to the entire vegetable industry from breeders, seed companies, growers, consultants, researchers, to Extension personnel. However, despite their importance VVT have always been given little-to-no scientific merit. In a period where resources are limited, regional VVT may provide a way for Land Grant institutions to include VTT as an entire part of their effort. This presentation will discuss the advantages (better use of resources, increased service to industry), challenges (credit given to VTT authors during tenure, timeliness of publication, uniformity of methods), and opportunities (publications in Hort Technology, regional publication, VTT web page, SR-IEG) associated with VVT. Participants will be given an opportunity to express their opinion through a questionnaire. Together with industry response, results will be used to inform the administration and work toward a regional VTT for the Southeast.
Effect of Forcing Temperature on Time to Flower of Coreopsis grandiflora, Gaillardia ×grandiflora, Leucanthemum ×superbum, and Rudbeckia fulgida
Authors: Yuan Mei , Carlson William H. , Heins Royal D. , Cameron Arthur C.
Published: February 2019

Scheduling crops to flower on specific dates requires a knowledge of the relationship between temperature and time to flower. Our objective was to quantify the effect of temperature on time to flower and plant appearance of four herbaceous perennials. Field-grown, bare-root Coreopsis grandiflora (Hogg ex Sweet.) `Sunray', Gaillardia ×grandiflora (Van Houtte) `Goblin', and Rudbeckia fulgida (Ait.) `Goldsturm', and tissue culture—propagated Leucanthemum ×superbum (Bergman ex J. Ingram) `Snowcap' plants were exposed to 5 °C for 10 weeks and then grown in greenhouse sections set at 15, 18, 21, 24, or 27 °C under 4-hour night-interruption lighting until plants reached anthesis. Days to visible bud (VB), days to anthesis (FLW), and days from VB to FLW decreased as temperature increased. The rate of progress toward FLW increased linearly with temperature, and base temperatures and degree-days of each developmental stage were calculated. For Coreopsis, Leucanthemum, and Rudbeckia, flower size, flower-bud number, and plant height decreased as temperature increased from 15 to 26 °C.
Storage and Handling Effects on a CO2-related Internal Browning Disorder of `Braeburn' Apples
Authors: Elgar H. John , Burmeister Douglas M. , Watkins Christopher B.
Published: February 2019

`Braeburn' apple (Malus ×domestica Borkh.) fruit can be susceptible to the development of an internal disorder called “`Braeburn' browning disorder” (BBD). Factors associated with development of this disorder were investigated. Susceptibility to injury was greater in fruit exposed to 2 or 5 kPa CO2 than to 0 kPa CO2 during storage. Susceptibility also increased with decreasing O2 partial pressure in the range of 5 to 1 kPa in the storage atmosphere. However, fruit stored in 1 kPa O2 remained firmer than those stored at higher partial pressures, regardless of CO2 level. BBD appeared to develop during the first 2 weeks of storage, and delays in air at 0 °C prior to controlled-atmosphere (CA) storage decreased incidence and severity of the disorder. The incidence of BBD was also reduced when the time to establish CA conditions was prolonged. We recommend that `Braeburn' apples be stored under CA conditions of ≤1.0 kPa CO2 and 3.0 kPa O2. Delayed application of CA for 2 weeks after fruit enter the coldstorage may also reduce development of BBD.
Interactions of Poultry Litter, Polyethylene Mulch, and Floating Row Covers on Triploid Watermelon
Authors: Baker J.T. , Earhart D.R. , Baker M.L. , Dainello F.J. , Haby V.A.
Published: February 2019

Triploid watermelon (Citrullus lanatus Thunb.) was grown on the same plots in 1990 and 1991 and fertilized with either poultry litter or commercial fertilizer. Additional treatments included bare soil or plots mulched with black polyethylene, and plots with or without spunbonded fabric row covers over both bare soil and mulch. Watermelon yields were unaffected by fertilizer source in 1990 but were significantly higher for poultry litter than for commercial fertilizer treatment in 1991. Polyethylene mulch significantly increased postharvest soil NO3 and leaf N concentrations in 1990 and increased yield and yield components in both years. There were no beneficial effects of row covers on yield in either year, presumably because no early-season freezes occurred.
Water Relations and Canopy Characteristics of Tall Fescue Cultivars during and after Drought Stress
Authors: Huang Bingru , Fry Jack , Wang Bin
Published: February 2019

Understanding factors associated with drought resistance and recovery from drought stress in tall fescue (Festuca arundinaces Schreb.) is important for developing resistant cultivars and effective management strategies. Our objective was to investigate water relations, photosynthetic efficiency, and canopy characteristics of tall fescue cultivars (forage-type `Kentucky-31', turf-type `Mustang', and dwarf-type `MIC18') in responses to drought stress and subsequent recovery in the field and greenhouse. During drought stress under field conditions, `MIC18' had lower turf quality, more severe leaf wilting, and higher canopy temperature than `Mustang' and `Kentucky-31', indicating that `MIC18' was more drought-sensitive. The greenhouse study comparing `K-31' and `MIC18' showed that leaf water status, chlorophyll fluorescence, canopy green leaf biomass, and lead area index of both cultivars declined as soil dried. Reductions in relative water content, leaf water potential, chlorophyll fluorescence, canopy green leaf biomass, and leaf area index were more severe and occurred sooner during dry down for `MIC18' than for `Kentucky-31'. After rewatering following 14 days of stress, leaf water deficit and turf growth recovered, to a greater degree for `Kentucky-31' than for `MIC18'. However, soil drying for 21 days caused long-term negative effects on leaf photosynthetic efficiency and canopy characteristics for both cultivars.
Surfactants Improve the Response of Grapevines to Hydrogen Cyanamide
Authors: Dokoozlian N.K. , Ebisuda N.C. , Neja R.A.
Published: February 2019

The effects of surfactants on the efficacy of hydrogen cyanamide (H2CN2) applied to `Perlette' grapevines (Vitis vinifera L.) grown in the Coachella Valley of California were examined in 1994 and 1995. Vines were pruned in mid-December in both years and treatments applied at 1000 L·ha-1 the following day to dormant spurs and cordons using a hand-held spray wand. In 1994, H2 CN2 was applied at 0.5%, 1%, or 2% by volume in combination with 0%, 0.5%, 1%, 2%, or 3% by volume of the amine-based surfactant Armobreak. In 1995, H2CN2 was applied at 0.5%, 1%, or 2% by volume in combination with Armobreak at 0% or 2% by volume. In 1994, budbreak rate was highly dependent upon H2CN2 concentration when 0 % to 1 % Armobreak was used; budbreak was generally most rapid for vines treated with 2% H2CN2 and slowest for vines treated with 0.5% H2CN2. When 2% or 3% Armobreak was used, however, little effect of H2CN2 concentration was observed. Results were similar in 1995, but the budbreak of vines treated with 2% H2CN2 + 2% Armobreak lagged behind that of vines treated with 1% H2CN2 + 2% Armobreak. The number of days after treatment required for 70% budbreak generally declined as the concentrations of H2CN2 and Armobreak were increased. A separate experiment conducted in 1995 revealed that several surfactants varying in chemical composition, Armobreak, Activator 90 and Agridex, had similar effects on H2CN2 efficacy. The results indicate that the addition of surfactants to H2CN2 solutions can significantly reduce the amount of active ingredient necessary for maximum efficacy on grapevines. Chemical names used: hydroxypolyoxyethylene polyoxypropylene ethyl alkylamine (Armobreak); alkyl polyoxyethylene ether (Activator 90); paraffin petroleum oil (Agridex).
Role of Foliar Phenolics in Host Plant Resistance of Malus Taxa to Adult Japanese Beetles
Authors: Fulcher Amy F. , Ranney Thomas G. , Burton James D. , Walgenbach James F. , Danehower David A.
Published: February 2019

Japanese beetles (JB), Popillia japonica Newman, are destructive, highly polyphagous herbivores that show a general preference for Rosaceous plants. Choice and nochoice feeding assays were conducted to determine the level of resistance among 10 taxa of Malus spp. Mill. Under no-choice conditions, M. baccata (L.) Borkh. `Jackii', M. × `Hargozam' Harvest Gold and M. transitoria (Balatin) Schneider `Schmitcutleaf' Golden Raindrops were highly resistant, with <2 cm2 leaf area consumed in 24 hours. M. × `Radiant' was highly susceptible, with 7.6 cm2 consumed, and the remaining six cultivars were intermediate. Under choice conditions, eight taxa were resistant with <10% defoliation, M. × `Red Splendor' was intermediate with 26%, and M. × `Radiant' was susceptible with 73% defoliation. Feeding responses to eight individual phenolics were tested in artificial diets over a range from 0 to 100 mm. Phloridzin, phloretin, naringenin, and catechin were all feeding deterrents, whereas quercetin and rutin were feeding stimulants. Chlorogenic acid stimulated feeding at low concentrations and deterred feeding at higher concentrations (i.e., a peak response). Kaempferol had no effect. Analysis of endogenous foliar phenolics showed considerable variation in concentrations among taxa. Stepwise multiple regression analysis identified phloridzin as the only endogenous phenolic that was significantly related to resistance under both choice and no-choice feeding conditions.
Freeze-dried Spinach Powder Inhibits Growth of Listeria Species and Strains in Tryptic Soy Broth
Authors: Babic Isabelle , Watada Alley E.
Published: February 2019

A study was undertaken to determine the inhibitory effect of freeze-dried spinach (Spinacia oleracea L.) powder and its native mesophilic aerobic microorganisms (MAM) on the growth of six strains, representing three species, of Listeria in tryptic soy broth (TSB). The cultures were incubated at 10 °C and growth was measured daily. Both spinach powder and MAM inhibited growth; maximum populations at 6 days were 8.8 Log10 colony-forming units (cfu) per mL-1 in control, 6.4 in spinach powder cultures, and 7.4 in MAM cultures. These results indicated that growth of various Listeria species/strains was affected by the bacteriostatic effect of spinach powder and competitive effect of native microorganisms.