bluuebunny/crossref_metadata_2025 huggingface dataset:
(172) The Influence of Environment, Media, and Zerotol on Forcing and In Vitro Establishment of Softwood Shoots from Large Stem Segments of Acer saccharinum and Fraxinus pennsylvanica
Authors: Aftab Faheem , Mansouri Katayoun , Preece John E.
Published: February 2019

The objectives of this research were to study the effects of three environments (lab, mist, or fog), four media treatments [perlite, vermiculte, 1 perlite: 1 vermiculite (by volume), or a control (empty flats)] and zerotol treatments on shoot forcing and subsequent transfer of explants to in vitro conditions. Stem segments from field-grown trees were cut to 40-cm lengths before being placed in flats with the media treatments. Half of the flats under mist and fog were drenched weekly with zerotol (0.18% H2O2). In a separate study, silver maple was forced under mist and drenched weekly with zerotol at 0%, 0.09%, 0.108%, 0.135%, 0.18%, 0.27%, or 0.54% H2O2. Shoots (≥5 cm) were harvested and nodal and shoot tip explants were surface disinfested and placed in vitro on DKW medium with 10-8 M thidiazuron plus 1.0 μM indolebutyric acid. Species did not interact with environment, media, or zerotol treatment, and silver maple produced a mean of 6 shoots per stem segment, while green ash produced a mean of 1.2 shoots. There was a significant interaction among perlite, vermiculite and environment, with the most shoots (6.7/stem segment) produced under mist in the perlite: vermiculite mix. Silver maple explants from the lab had only 4% microbial contamination, whereas 68% of explants from fog and 92.2% of explants from mist were contaminated. When forcing was under fog, in perlite, and drenched with zerotol, explants had a 43% rate of contamination. In a separate study, when silver maple stems were placed under mist and drenched weekly with 0.18% H2O2, 46% (18 of 39 explants) established cleanly in vitro. Contamination was higher with misted explants that were drenched with higher or lower concentrations of zerotol.
(240) Mode of Inheritance for Leaf Shape and Main Vein Color in Caladium
Authors: Deng Zhanao , Harbaugh Brent
Published: February 2019

Caladiums (Caladium×hortulanum) are ornamental aroids often forced in containers or grown in the landscape for their colorful leaves. The aesthetic value of caladium plants is largely determined by their leaf characteristics. Caladium breeding can be traced back to the mid-1800s when Gregor Mendel conducted his plant hybridization experiments, but information on the inheritance of caladium traits has been rather scant. To understand the mode of inheritance for three typical leaf shapes and three main vein colors in caladium, controlled crosses were made among commercial cultivars and breeding lines, and segregation of leaf shape and/or main vein color in the progeny was analyzed. The observed segregation ratios indicated that a single locus with three alleles seemed to determine the main vein color in caladium. The white vein allele was dominant over the green vein allele, but recessive to the red vein allele, which was dominant over both white and green vein alleles. The three leaf shapes (fancy, lance, and strap) in caladium seemed to be controlled by two co-dominant alleles at one locus. Leaf shape segregation was skewed in some crosses, which might imply the existence of other factors involved in caladium leaf shape development. Chi-square tests revealed that leaf shape and main vein color were inherited independently in caladium.
(30) Edaphic Factors on Crack Development of Cut and Peel Carrots
Authors: Joy Phillip , Lada Rajasekaran , Fullerton Cameron , Williams Brian , Ells Angus
Published: February 2019

The quick-frozen (QF) cut and peel processing industry is growing and has significant economical importance. Crack development formation (CDF) and enhancement is a major obstacle in QF carrot processing since it lowers product quality, profitability and consumer preference. Studies were initiated to determine the role of edaphic factors on crack development. Carrot samples (var. Sugarsnax) were collected from nine different fields before processing, after processing, and after 8 weeks of -8 °C freezer storage. Samples were tested for the percent cracked; the length, width, and depth of cracks; and membrane stability using electrical conductivity per gram (EC/g). Membrane injury index (MII) was also analyzed on freezer-stored samples. Very few cracks and low EC readings were observed in treatments prior to processing, with the exception of field VC38. Samples taken at the end of the processing line had a higher percentage of visual cracks and significant differences were found between fields in EC/g and length, but not in width or depth of cracks. Freezer-stored samples had significant differences in all parameters, including EC/g, MII, crack length, width, and depth, indicating that the length of freezer storage time can increase the potential for crack development. Samples from V49 cracked heavily during 8 weeks in freezer storage compared to the samples from other fields. A significant interaction between field and time was also observed in processed samples, indicating that CDF is dependent on both field parameters and freezer storage time. Significant differences were observed among different fields in terms of crack morphology, especially after 8 weeks in freezer storage.
(307) NFT versus Subirrigation: II. Tomato Fruit Quality Grown in Closed Soilless Systems under Salinity or Water Stress
Authors: Montesano Francesco , Ferulli Cristina , Parente Angelo , Serio Francesco , Santamaria Pietro
Published: February 2019

Nutrient solutions (NS) containing moderate to high concentrations of salts are frequently supplied to improve the taste of tomato fruits grown in soilless systems. The aim of this study was to determine whether salinity and water stress affect the tomato fruit quality similarly. The research was conducted in Mola di Bari, Italy, during Autumn 2004, and compared the nutrient film technique (NFT) with the trough-bench technique [Subirrigation (SUB)] in terms of tomato (Lycopersicon esculentum Mill. cv. Kabiria) fruit quality. In the NFT, the plants were grown with two electrical conductivity (EC) levels (2–4 and 6–8 dS·m-1) of NS. The highest EC was obtained by increasing all the ions in the NS. In the SUB system, two water tensions (-4 and -8 kPa) of substrate (perlite) were examinated. At harvest, in each cluster (six/plant), fruit dry matter (DM) and total soluble solids (TSS) were determinated. In the fourth and sixth cluster, vitamin C content and titratable acidity were determined. Total yield was not influenced by either soilless system, while the average weight of the fruit was lower in the SUB. The DM and TTS were influenced by soilless system (on average, 6.6 vs 7.3 g/100 g of fresh matter and 5.3 vs. 5.9 °Brix, with NFT and SUB, respectively). Both of the stresses resulted in the increase of DM and TSS, principally in SUB (water stress) in respect to NFT (salinity stress), while vitamin C and titratable acidity were not influenced by soilless system or water/salinity stress (25.2 mg/100 g fresh matter and 0.45 g/100 mL of citric acid juice, respectively). Results of NFT with the highest EC of NS exceeded 9 dS·m-1, without any stress symptoms in the plants, while EC in the SUB system remained unchanged (about 2.5 dS·m-1).
(66) Modeling Flower Bud Development of Impatiens hawkeri and I. walleriana
Authors: Faust James E. , Lewis Kelly P.
Published: February 2019

Three cultivars of New Guinea impatiens (Impatiens hawkeri) and two cultivars of double impatiens (I. walleriana) were grown in greenhouses maintained at 15, 20, and 25 °C. Bud diameter was measured twice weekly on five plants per cultivar from the time of visible bud to open flower. The experiment was repeated twice. For New Guinea impatiens, the time from visible bud (1-mm diameter) to open flower was 31, 43, and 72 days at 25, 20 and 15 °C, respectively. Flower bud diameter increased linearly as the bud expanded from 1 to 9 mm. For double impatiens, the time from visible bud (1-mm diameter) to open flower was 25, 30, and 58 days at 25, 20 and 15 °C, respectively. Flower bud diameter increased at an increasing rate (curvilinear response) as the bud expanded from 1 to 8 mm. These models are currently in commercial use to aid greenhouse growers in accurately timing crops for specific market dates.
(271) Expression of the NRT1 Gene in Cornus and Rhododendron
Authors: Sandrock David R. , Azarenko Anita N. , Martin Ruth M. , Bassil Nahla V.
Published: February 2019

The NRT1gene family encodes transport proteins with dual or low affinity for nitrate. The objectives of this experiment were to develop a system that could be used to compare the expression of the NRT1genes between species. This was accomplished by comparing sequences of NRT1homologues from various species and designing degenerate primers in regions of high homology. These primers were used to amplify a region of the NRT1gene from species of interest. A 635 bp PCR product was amplified from each species using the MD2-1 (5' ATGTTACCAAYWTGGGCMAC-3') and MD2-2 (5'-GCCAMWARCCARTAGAAAT-3') primers. The PCR products were cloned and sequenced. At the nucleotide level, CornussericeaL. `Kelseyi' and RhododendronL. `Unique' were 79.52% identical. Species-specific primers were designed and used for RT-PCR to compare NRT1expression in roots of hydroponically grown C. sericea, C. sericea `Kelseyi', and Rhododendron`Unique'. The relative levels of NRT1expression, normalized using 18S rRNA as a standard, were ≈3.2 to 1.7 to 1.0 for C. sericea, C. sericea `Kelseyi', and Rhododendron`Unique', respectively. This approach may eventually be used to examine nitrate uptake potential in different taxa of plants at different times during the growing season.
(272) DNA Markers Linked to the Resistance Gene of Scab in Oriental Pear (Pyrus sp.)
Authors: Cho Kang-Hee , Shin Il-Sheob , Hong Seong-Sig , Kim Ki-Taek , Song Hwa-Suk , Kang Sang-Jo , Mok Il Gin
Published: February 2019

Pear scab caused by Venturianashicolais one of the most important diseases of oriental pear. Breeding a variety resistant to scab can be improved through marker-assisted selection (MAS). Bulked segregant analysis (BSA) and amplified fragment length polymorphic (AFLP) analysis were performed to identify DNA markers linked to the scab-resistant gene (Vn) using a population from a cross between PS2-93-3-98 (resistant parent) and Yali (susceptible parent). A total of 480 EcoR I/MseI primer combinations were used to identify markers specific to PS2-93-3-98 and resistant pool. Three AFLP markers linked to Vn, E-AGT/M-CCA245, E-ATT/M-CCG300, and E-GGT/M-TCT225, were selected. Linkage analysis between the selected markers and Vn locus was conducted with 51 individual plants. The selected markers, E-AGT/M-CCA245, E-ATT/M-CCG300, and E-GGT/M-TCT225, were located at 3.9, 3.8, and 1.2 cm away from Vn, respectively. For practical application, we are currently converting selected markers to simple PCR-based markers. The markers could be used to increase selection efficiency in pear-breeding programs for scab resistance.
(424) Vigor Testson Lettuce Seeds and Their Correlation with Emergence
Authors: Contreras Samuel , Barros Margarita
Published: February 2019

The main objective of this study was to evaluate some of the available seed vigor tests to predict lettuce (Lactuca sativa L.) seedling emergence. Eight lettuce seed lots were evaluated by the following laboratory vigor tests: germination (GT); accelerated aging (AA); saturated salt accelerated aging (SSAA); conductivity (EC); and seed vigor imaging system (SVIS). Also evaluated were the percentage (EP) and speed (ES) of the seed lots' emergence under three conditions: seedling trays (ST) filled with a mixture of peat (80%) and perlite (20%); boxes with a clay loam soil (BS); and boxes with a mixture of clay loam soil (66%) and sand [34% (BSS)]. Correlation coefficients among the laboratory and emergence test results were calculated and significant differences were found. The correlation coefficients between EC results and each emergence parameter were nonsignificant, while AA results were only significantly correlated with the emergence percentage for BSS. GT values and emergence results were significantly correlated in all cases. SSAA results were equally or more positively correlated than GT results with the EP and, for the three sowing conditions, they were more correlated with the ES than GT values. Vigor index results from the SVIS were significantly correlated with both emergence parameters, and its correlation with emergence on ST (EP and ES) was greater than GT values. The results of this study showed that SSAA and SVIS were the best laboratory tests for lettuce seed vigor evaluation, especially for seed lots to be used for plug seedling production.
(429)“Artificial Exosperm” Development Using Antistress, Antioxidant Compounds for Promoting and Synchronizing Seedling Emergence at Limiting Low Temperature and Moisture Conditions in Carrot
Authors: Briscoe Rowan , Lada Rajasekaran , Caldwell Claude , Sibley Kevin , Pettipas Christine , Stiles Azure
Published: February 2019

Producing carrots with optimal root grades is the most critical aspect of carrot production for maximizing profits. Desired root grades can be optimized by maintaining optimal plant population. While precision seeding helps to seed required seeding rate, obtaining optimum seed germination and uniform emergence, especially in mineral soils and under cold and dry climates, have been great challenges to carrot producers around the world. Therefore, stand establishment is critical for optimizing yield and quality in carrots. Experiments were conducted to identify suitable germination and emergence promoters (GEPs) that will promote early and uniform emergence under temperatures of 5 °C and 20 °C and under 20% FC and 40% FC combinations. GEPs, belonging to both natural and synthetic antistress, antioxidant groups of compounds, and mineral salts were used. Carrot seeds of cv. Oranza were used in this study. Seeds were preconditioned with various GEPs, then submerged into laponite RD gel that was used as a potential “artificial exosperm” for carrot seeds. Data on emergence was collected and emergence and vigor value was calculated. Under ideal conditions, that is, at the 20 °C and 40% FC combination, there was no significant difference between treated seeds and untreated control. Germination was delayed at the 5 °C and 20% FC combination. However, seeds preconditioned with GEP-PN1.5%, GEP-LU at 1 mg·L-1, GEP-CA at 10 mg·L-1, GEP-AA at 100 mg·L-1 and GEP-SD at 10 mg·L-1 all promoted emergence resulting in the highest number of seedlings emerged at 5 °C and at 20% FC. Enhanced emergence under low temperature and low moisture may perhaps be due to synthesis of specific proteins.
(359) Production of the Print-on-dem and Publication Weeds of Guam
Authors: McConnell James , Marutani Mari , Schlub Robert , Raulerson Lynn , Gutierrez Lauren , Perez Gregoiro
Published: February 2019

This publication was produced with the goal of printing the booklet on demand. The photographs were from multiple sources: scanned film, digital photographs (camera), and digital photographs (flatbed scanner). Fifty-six plants were included. Each plant was allocated four half-letter-size pages (one double-sided letter). These four pages include text descriptions of the plants and about nine images to give the user information on habit, seed, fruit, inflorescence, flower, stem characteristics, leaf pattern, pest damage, and other unique characteristics. Magnified images were used as necessary. The original digital images were in either TIFF or RAW format. The final images were in either TIFF or PSD format. Images were edited in Adobe Photoshop and various plug-ins used to enhance the images to optimize color and information that could be obtained from the printed image.
(361) Public Domain Computer Programs for Quantifying Size and Shape in Horticultural Research
Authors: Villordon Arthur , Franklin Jason
Published: February 2019

Shape measurements in horticultural research have generally been expressed as ratios or indexes. Computer-based image analysis enables the objective quantification and statistical analysis of two-dimensional sample shape variability. In addition, the availability of public domain software facilitates the inexpensive but accurate quantification of object shape in horticultural research. We describe the procedures for measuring sample shape using the following publicly available software: ImageJ, ImageTool, and SHAPE. Using U.S. #1 sweetpotato storage root samples from plots subjected to various weed control treatments, we detected significant differences in elongation, compactness, as well as shape attributes. We also measured size and shape variability from representative fruit, leaf, and floral organ samples. The results demonstrate that, where possible, measurement of two-dimensional samples can be undertaken inexpensively and accurately using public domain software applications.
(42) Sun Exposures Impact the Postharvest Quality and Firmness of Harvested Bell Peppers
Authors: Muy-Rangel Maria Dolores , Cantwell Marita
Published: February 2019

Temperature management of fresh products begins with proper handling at harvest. Inadvertent abuses, such as lengthy delays to cool or exposure of harvested product to the sun, can detrimentally impact postharvest quality. We used mature-green bell peppers to determine the periods of sun exposure (midday during August in Davis, Calif.) necessary to affect quality attributes (visual appearance, gloss, weight loss, and firmness). Peppers were evaluated after cooling, storage at 7.5 °C for 3 or 7 days, and storage plus 2 days at 20 °C. The impacts of sun exposure, although sometimes barely detectable after cooling, became more noticeable once the peppers were stored. The additional transfer period to 20 °C after storage further accentuated the impact of the exposure. Depending on the experiment, sun-exposed areas reached 45 to 55 °C within 1 hour. Peppers typically lost 0.4% to 0.5% and 1.0% to 1.3% weight during 1- and 2-hour exposures, respectively. Changes in gloss and firmness (whole fruit compression and pulp penetration) were preceded by changes in visual appearance. Exposure to the sun for 0.5 hour did not impact postharvest quality of peppers. Exposures from 1 to 1.5 hours usually resulted in changes apparent only after the storage period. Such exposures are problematic in commercial situations because these peppers are unlikely to be eliminated during sorting on the packingline. Exposures of 1.5 to 2 hours usually resulted in an immediate change in appearance (pitting, blistering, color change).
(187) Zucchini and Yellow Squash Variety Evaluation Results
Authors: Infante-Casella Michelle L. , Henninger Mel
Published: February 2019

Zucchini and straightneck yellow squash are important crops for vegetable farmers. Variety choices change from year to year, based on breeding programs that try to find disease tolerance or resistance by developing new lines. A study was conducted at the Rutgers Agricultural Research and Extension Center in Bridgeton, N.J., to determine yield and quality of 14 zucchini, 6 yellow squash, and 5 specialty squash varieties. Squash were seeded on 17 May 2004, at 30 inches between holes into black plastic mulch on high raised beds. Rows were spaced 60 inches apart. Drip irrigation was used for supplying water and fertigation. Prefar4E at a rate of 5 qt/acre applied on the soil surface just before laying plastic was used for preemergent weed control. Five days after planting, Sandea75WF at a rate of 1 oz/acre and Gramoxone Max 3SC at a rate of 1.5 pt/acre were applied with a backpack sprayer between the rows for added weed control. Admire was applied in the seed hole at a rate of 24 oz/acre after planting using a backpack sprayer for control of aphids and cucumber beetle. Harvests began on 22 June 2004, and were continued 3 times weekly for 5 weeks for a total of 15 harvests. Zucchini varieties `Revenue', `Cashflow', `Justice III', `Spineless Beauty', `Senator', `HMX-2724', and `EXT 04629728' had statistically higher yields than did `Radiant', `Wildcat', `Payroll', `HMX-2723', `Lynx', `Tigress', and `Independence II'. Varieties are listed in values from highest yielding to lowest yielding, respectively. All yellow squash varieties had statistically similar yield values. These included `General Patton', `Cougar', `Sunray', `XPT1832', `Goldbar', `Sunbar'. Specialty varieties evaluated included `Zephyr', `Starship', `Magda', `Flying Saucer', and `Costata Romanesco'
(457) An Approach-grafted, Split-rooted Apple System to Evaluate the Effects of Partial Rootzone Drying and Deficit Irrigation on Tree Water Relations
Authors: Einhorn Todd C. , Caspari Horst W. , Green Steve , Litus Greg
Published: February 2019

One-year-old `Gala'/M7 apple trees were potted into 30-L containers and approach-grafted about 45 cm above the graft union in late Spring 2003. Trees were grown with both tops for the remainder of the 2003 season in a greenhouse. In Apr. 2004, one of the tops was removed. Trees were fully watered by an overhead irrigation system until July 2004, when trees were subjected to one of four irrigation regimes: control received >100% of ETc applied evenly to the two pots; PRD100 received >100% ETc applied to one pot only; and two regimes received 50% ETc applied to either one (PRD50) or both pots (DI50). Both gravimetric (tripod) and volumetric (time-domain reflectometry) soil moisture measurements were taken daily prior to and after irrigations. In addition, heavy isotope H2O (18O) was applied to one of the two root compartments and analyzed in the leaves to further determine the validity of the model. Sap flow was monitored in six split-rooted trees using miniaturized heat-pulse probes inserted into the stem above the graft union and into each of the two root systems below the graft union. Under fully irrigated conditions, root sap flow was proportional to root trunk cross-sectional area, and was not a function of root system origin (i.e., roots of mother plant with original top remaining or roots of daughter plant with original top detached). Water uptake from a previously dried root zone was rapid when the irrigated side was switched, but much more gradual when the other side was maintained wet. Interactions between soil moisture and sap flow in relation to factors governing canopy demand will be presented.
(325) Soil Solarization and Methyl Bromide Fumigation Alter Fine Root Dynamics at a Peach Replant Site
Authors: Tanner Shann , Wells Christina , Reighard Gregory
Published: February 2019

The effectiveness of soil solarization as an alternative to methyl bromide (MBr) fumigation in replanted peach orchards was investigated at the Musser Fruit Research Farm near Clemson, S.C. A split plot experimental design was used, with soil treatment as the whole-plot factor and rootstock as the sub-plot factor. In Spring 2002, preexisting trees were removed from the study site, and six orchard rows were cultivated and subsoiled. In June, two rows were covered with clear polyethylene sheeting and solarized for the remainder of the summer. In November, two additional rows were treated with MBr (474.3 kg·ha-1), while the two remaining control rows received no soil sterilization treatment. In Jan. 2003, 36 `Redglobe' peach trees budded on Guardian™ or Lovell rootstock were transplanted to the site, and one minirhizotron was installed beneath each tree. Minirhizotron observations were made every 14–21 days from Feb. through Oct. 2003, and stem caliper measurements were taken on four dates during this interval. Trees grew significantly larger in the MBr and solarized rows than in the control rows (P< 0.1; Tukey's hsd), but there were no differences in stem caliper growth between MBr and solarization-treated trees. Reduced aboveground growth in control trees may have been related to greater carbon expenditure belowground: in the absence of soil sterilization, fine root median life spans were reduced by 27–28 days (P< 0.0001; proportional hazards regression) and rates of root production and mortality were significantly higher (P< 0.1; repeated measures ANOVA). Solarization and MBr fumigation appeared to provide similar benefits in reducing root turnover and improving aboveground growth at this site.
(13) Comparative Mapping of Early Blight Resistance QTLs and Candidate Resistance Genes in F2, F3, F4 and a RIL Population of Tomato
Authors: Ashrafi Hamid , Sharma Arun , Niño-Liu David , Zhang Liping , Foolad Majid
Published: February 2019

Most cultivars of tomato (Lycopersiconesculentum) are susceptible to early blight (EB), a devastating fungal (Alternariasolani) disease of tomato in the northeast and eastern part of the U.S. The most economic and durable measure of disease control is by using genetic resistance. There is limited EB resistance within the cultivated tomato. However, genetic sources of resistance exist within the tomato-related wild species L. hirsutum and L. pimpinellifolium. Early blight resistance does not follow the gene-for-gene model of host–pathogen interaction. Mapping QTLs conferring horizontal resistance is an effective approach for studying complex resistance traits such as EB. We have developed F2, F3, F4, and an F2:7 derived RIL population of a L. esculentum× L. pimpinellifolium cross and evaluated them for EB resistance under field conditions. Genetic maps were constructed based on the F2 (including 256 RFLP, EST and RGA markers) as well as the RIL population (including over 220 RFLP and EST markers). In each of the F2, F3, and F4 population, an average of seven QTLs were identified for resistance, which were highly consistent across populations. Mapping of EB resistance QTLs in the RILs is underway. Co-localizations of QTLs with several ESTs and RGAs were observed, suggesting potential involvement of the latter markers with EB resistance. Furthermore, co-localizations were observed among QTLs, ESTs, and RGAs and several known tomato vertical disease resistance genes. Possible occurrence of such co-localization in the RIL population will be reported. It is speculated that candidate-gene approach is an effective way of identifying and mapping new R genes in tomato. This study may lead to the identification of genes underlying EB resistance in tomato.
(81) Fine Fescues and Shade Tolerance
Authors: Paranick Tara E. , Lang N. Suzanne
Published: February 2019

Shaded environments present major obstacles for establishing high quality, persistent, and resistant turfs. Exogenous fructose applications are being examined as a potential method to counteract the effects of shade on turf. This work examines the effectiveness of fructose applications under different light levels on two fine leaf fescue cultivars: chewings fescue (Festucarubra var. commutata) `SR5100' and creeping red fescue (Festucarubra var. rubra) `Dawson'. The experiment was conducted at Michigan State University, East Lansing, inside a simulated dome environment. The experiment was a randomized complete-block design that began 21 Oct. 2004 with two main factors: light and fructose. There were three light treatments: ambient light (shaded); supplemental high light; and supplemental low light. Fructose (0% or 1.25% weight/volume), dissolved in water with an organosilicone adjuvant, was applied once per week. Quality and color ratings, clippings, core samples, density, and leaf reflectance were recorded. In addition, light response curves (LRC) were taken inside an Econoair®

growth chamber using a LI-COR-6400® on the fine fescues, kentucky bluegrass (Poa pratensis) `Cynthia', and bermudagrass (Cyondon dactylon) `Princess'. Preliminary results show that fructose had no significant effect in each light treatment for turf quality and color. However, fructose had a significant impact on clipping weights and density. The LRC specified the required and potential carbon needs as well as indicated the threshold levels, respectively, by species. The impact of fructose alone and in combination with supplemental light on photosynthesis efficiency will be presented.
(147) In the English Landscape
Authors: Dana Michael N. , Siciliano Paul C. , Larson John L.
Published: February 2019

International travel and study courses for undergraduate students can be significant academic learning experiences if there is a well-defined curriculum and high expectations for student performance on homework exercises, class discussions and evaluation instruments. An interdisciplinary perspective serves to broaden students' understanding. “In the English Landscape” is a three-credit, 4-week undergraduate course in-residence, primarily in Corsham, Wiltshire, U.K. Students explore the history of English landscapes and gardens in the context of post-medieval British history. The course is team-taught every other year by Purdue faculty from the Horticulture, History and Landscape Architecture programs. Excursions to landscape, garden and cultural sites provide the primary basis for student discovery. Pretravel readings and lectures prepare students for in-country, site-specific worksheets and class discussions. Course philosophy, content, structure, logistics, and instructional materials, which may be useful as a basis for course development by educators at other institutions, are presented.
(104) Green Ash (Fraxinus pennsylvanica) Response to Nitrogen Rate and Timing in a Field Nursery
Authors: Neal Catherine
Published: February 2019

Bare-root, 4-ft whips of green ash (Fraxinus pennsylvanica `Marshall's Seedless') were planted in June 2001 in a randomized complete-block design with three trees per plot. An incomplete factorial design was used to test whether annual fertilizer rate and/or application dates affected growth. Treatments were fertilized from 0 to 4 times per year in mid-April, mid-June, mid-August, and/or mid-October. A rate of 1 lb of nitrogen (N)/1000 sq ft was used whenever fertilizer was applied to a plot. Each treatment received 0, 2, 3, or 4 lbs N/1000 sq ft/year depending on the number of applications. Caliper, height, and terminal growth were measured annually for three growing seasons. At the end of seasons 2 and 3, one plant per plot was destructively harvested and processed to obtain dry weights of shoots and roots, and the shoot to root ratio was calculated. Data were analyzed by analysis of variance with least square means contrasts. Treatment effects on top weights, root weights, and shoot to root ratios were nonsignificant. There were significant treatment differences for caliper and terminal growth in years 1 and 2, but not 3. A set of orthogonal contrasts was used to determine that the effect was due primarily to growth differences in plants receiving 2 vs. 3 or 4 lbs N/1000 sq ft/year, but that 3 vs. 4 lbs made no difference. Another set of planned, but nonorthogonal contrasts was used to compare application date effects. Plants fertilized in June were greater in caliper and terminal growth in the first 2 years than plants not fertilized in June. There were nonsignificant effects of fertilizing vs. not fertilizing in late fall or early spring.
(281) Effects of Colchicine and Oryzalin on Callus and Adventitious Shoot Formation of Euphorbia pulcherrima `Winter Rose'™
Authors: Pickens Kimberly A. , Cheng (Max) Zong-Ming , Kania Stephen A.
Published: February 2019

Poinsettia, Euphorbia pulcherrima, is an important holiday symbol and is the number one flowering potted plant in the United States. The technique of chromosome doubling has been utilized to increase size of flowers, stems, and leaves of many species, and has been used in poinsettia breeding to obtain new cultivars. Application of colchicine or oryzalin to in vitro tissues may be used to enlarge the inflorescences and brackets and reduce the height of `Winter Rose'™ poinsettias, reduce the likelihood of chimeric tetraploids, and provide a rapid means for producing many tetraploid plants. The purpose of this research was to evaluate the effect of colchicine and oryzalin on callus and adventitious shoot formation of `Winter Rose'™ poinsettia with in vitro grown leaf tissues and its potential for tetraploid induction. In vitro grown leaf midvein sections were placed on various media supplemented with either colchicine or oryzalin at various concentrations for 1–4 days. Colchicine was least damaging to leaf tissues at concentrations of 0.25 or 250.4 μm. A large amount of callus, as well as adventitious shoots, were produced. Regenerated shoots were found to be diploid, determined by flow cytometry. On media with oryzalin (28.9–144 μm), leaf tissues produced callus, but not adventitious shoots. Calluses produced on oryzalin-containing media were tested using the flow cytometer and were found to be diploid.
(200) Influence of Planting Density on Yield and Quality of Confectionery Seed Pumpkins
Authors: Lee Sung Eun , Pak Chun Ho , Lee Yong Beom , Hatterman-Valenti Harlene , Lee Chiwon W.
Published: February 2019

Afield study evaluated the influence of planting density on the yield and quality of confectionery seed pumpkins grown near Hatton, N.D. An open-pollinated selection of Chinese snow-white seeds (CS) and a hull-less (HL) seed cultivar (`Takai', Johnny's Selected Seeds) were grown at three different planting densities (1-, 2-, or 3-ft plant spacing on rows 5 ft apart) from 5 May to 7 Oct. The total number of plants at high, medium, and low densities was 8712, 4356, and 2904 per acre (21,529, 10,764, and 7176 plants per ha, respectively). The average number of fruits harvested at high, medium, and low densities, respectively, was 0.93, 1.2, and 1.4 per plant for CS and 1.2, 1.7, and 2.5 per plant for HL. Total seed yields were estimated at 1011, 599, and 466 kg/acre (2498, 1480, and 1151 kg·ha-1) for CS and 661, 500, and 498 kg/acre (1633, 1235, and 1231 kg·ha-1) for HL, respectively, at high, medium, and low planting densities. While the average weight of fruits decreased as planting density increased, the total number and weight of seeds produced per fruit were unaffected by changing plant density in either cultivar.
(210) Effect of Shading on the Germination and Vegetative Development of `Jalapeño' Hot Pepper (Capsicum annuum L.)
Authors: Tene Marcelino Bazan , Gonzalez Juan Manuel González , Juarez Francisco Radillo , Corner Jorge Pahul Covarrubias , Gonzalez Salvador Guzman
Published: February 2019

The hot pepper (Capsicum annuum L.) is a plant domesticated in Mesoamerica. Hot pepper is currently widespread worldwide, and its uses are varied, such as for flavoring, pigment base, and as a nutritional food resource. Mexico produces about 623,238 tons/year of fresh fruits in 136,398 ha; the State of Colima produced 17,181 tons in 676 ha, with a mean of 27 t·ha-1. The culture of hot pepper in Colima faces certain limitations to its productive potential, such as lack of fertile and well-drained soils, constant soil moisture, and being free of weeds during the first weeks after transplanting; and maintaining plant uniformity in transplantation. This last practice is carried out in the side bed, but there is a lack of scientific evidence about the requirements of luminosity in the seed nursery in order to accelerate improvement of plant quality for transplanting, and the impact on fruit yield. The aim of this study was to evaluate the effect of different levels of shading on germination and vegetative development of `Jalapeño' hot pepper under greenhouse conditions. Four levels of luminosity were evaluated using mesh fabrics in order to produce 90%, 75%, and 50% shade, and control (0%) without shading on the seed beds. A completely randomized design with four treatments and four replications was used. The shading treatments reduced the germination period in about 2 days; increased the percentage of germination with a range between 1.6% and 3.7%; increased the plant height 2.3, 4.8, 7.72, and 10.1 cm at 3, 7, 13, and 18 days postemergence; increased the root biomass about 7.1 g/plant, and 5.4 g of fresh foliage with the 90% shade treatment in comparison with control. Overall, a better agronomic performance of the `Jalapeño' hot pepper was obtained with 90% shading.
(370) In-row Plant Spacing Affects Early Season Fruit Yield of Strawberry Grown in a Winter, Annual Hill Production System
Authors: Chandler Craig K. , Legard Daniel E. , Xiao Chang-Lin , Mertely James C.
Published: February 2019

On standard two-row black polyethylene covered beds, `Camarosa', `Rosa Linda', and `Sweet Charlie' strawberry plants were grown at 23, 31, 38, or 46 cm within-row spacing during the 1997–98 and 1998–99 seasons at Dover, Fla. Ripe fruit were harvested twice weekly from December through March. The first 8 weeks of harvest was considered the early period; the late period consisted of all harvests after the first 8 weeks. The effect of spacing on early marketable yield was consistent across seasons and cultivars. The 23-cm spacing resulted in the highest marketable yield per unit area, followed by the 31-, 38-, and 46-cm spacing. The percentage of fruit that were small (unmarketable) was higher at the 23-cm spacing than at the wider spacings (40% vs. 35% or 36%), but spacing did not affect the percentage of fruit that were misshapen. For the late harvest period, a spacing effect on marketable yield occurred in 1998–99, but not in 1997–98. The 23-, 31-, and 38-cm spacings in 1998–99 resulted in similar late period yields, which were 15% to 21% higher than the yield resulting from the 46-cm spacing. These results indicate that marketable yields per plant during the late period were higher at the wider spacings.
(376) Carbon Mobilization and Yield Components in Raspberry
Authors: Alvarado Horacio E. , Darnell Rebecca L. , Williamson Jeffrey G.
Published: February 2019

Raspberry root growth during fruiting appears to be a strong sink for assimilates, and may decrease carbon availability for fruits and, consequently, cane yield. Both floricanes and primocanes may contribute to root carbon supply in raspberry during fruiting. To test this, `Tulameen' raspberry canes were grown outdoors in containers filled with perlite and peat (1:1). One-half of the plants were girdled and the rest were nongirdled. Within each girdling treatment, either 0 or 3 primocanes were allowed to grow. Treatments were applied at early bloom (10 May), and 50% fruit harvest occurred the first week in June. Fruit number and yield per plant decreased in girdled plants and plants without primocanes compared with nongirdled plants and plants with primocanes. Individual fruit fresh weight was not affected by treatments, but individual fruit dry weight and the dry weight to fresh weight ratio was higher in girdled plants without primocanes than in the other treatments. Neither girdling nor the presence of primocanes affected dry weight allocation to primocanes or floricanes. Root dry weight was higher in girdled plants with primocanes than in nongirdled plants without primocanes. It appears that primocanes supply carbon to roots during fruiting, and subsequently, roots mobilize carbon to floricanes. Thus, roots appear to serve primarily as a translocation pathway for carbon from primocanes to floricanes. However, when primocane growth is suppressed, root carbon is mobilized to support floricane development. If carbon flow from roots to floricanes is restricted, fruit number and yield is significantly decreased.
(351) Production of Rhododendron delavayi Franch.
Authors: Zhanying Gu , Xun Chen , Huamei Wu
Published: February 2019

Rhododendrondelavayi Franch. is an evergreen tree up to 5 m tall. Since few tree rhododendron are available in the market, the demand for this plant is high. Unfortunately, the supply is limited due to production difficulty. Under natural conditions (control), seed germination rates were 3% to 5%. When a special propagation bed was set up with mixed media of humus, loess, and sand, the germination rate reached 75% if the temperature was set from 20–25 °C, humidity was 80% to 90%, and irrigation water pH was 6–-6.5. In growing Rhododendrondelavayi, medium pH, water-holding capacity, aeration, and organic matter were considered. The medium, mixed with cinder, loess, humus, and perlite, yielded a 95% survival rate and the tallest plants. To produce aesthetically pleasing plants with flowers, apical dominance was removed and the growth of lateral buds was promoted by pinching the terminal buds of the seedlings in their second year. Also, 3N–1P–1K fertilizer should be used to increase seedling growth. With proper pruning, the seedlings were flowering and ready for market in 3–4 years (instead of 8 years under natural conditions). The acceptable germination rate, better growing conditions, and feasible cultural practices should enable growers to produce quality plants, which ultimately enhance the popularity of Rhododendrondelavayi.
(330) Growth and Nutritional Response of Six Citrus Rootstocks to Increasing Levels of Copper
Authors: Albano Joseph , Bowman Kim
Published: February 2019

Nutrient disorders related to excessive levels of copper in soils are common in Florida citrus groves that have been under production for many years, mainly due to the continual use of copper-containing pesticides. The objectives of the study were to investigate the growth and nutritional response of six citrus rootstocks (nonbudded) grown in 4-L containers in sand to increasing concentrations of copper. The rootstocks included: Swingle citrumelo (Citrusparadisi Macf. × Poncirus trifoliata [L.] Raf.), Volkamer lemon (C. volkameriana Ten. and Pasq.), Cleopatra mandarin (Citrusreticulata Blanco), Flying Dragon (P. trifoliata); and two new USDA series rootstocks, US-812 (Sunki mandarin × P. trifoliata released in 2001), and US-897 (a hybrid of Cleopatra × Flying Dragon not yet released). Copper was supplied at 0.05, 0.25, 1.00, and 2.00 mg·L-1 CuEDTA incorporated into a modified Hoagland's nutrient solution. As a mean of all Cu treatments, whole plant Cu levels (μg·g-1) were: Flying Dragon, 17.33; US-897, 21.68; Cleopatra, 27.33; US-812, 28.84; Swingle, 29.74; and Volkamer, 34.05. As a mean of all Cu treatments, foliar Cu levels (μg·g-1) were greatest and least in US-812 (7.74) and Cleopatra (4.05), respectively; and root Cu levels (μg·g-1) were greatest and least in Volkamer (61.08) and Flying Dragon (30.08), respectively.
(332) Fabric Cover Effects on Soil Fertility and Plant Nutrition of Sweet Cherry
Authors: Yin Xinhua , Turner Janet , Seavert Clark , Nunez-Elisea Roberto , Cahn Helen
Published: February 2019

Theinfluences of a synthetic fabric cover in the row area of sweet cherry trees on soil fertility and plant nutrition are largely unknown. A field trial has been conducted on young `Regina' sweet cherry on a sandy loam soil at the Mid-Columbia Agricultural Research and Extension Center, Hood River, Ore., since 2001. The difference in soil NO -3, P, K, Ca, Mg, S, B, Zn, Mn, Cu, pH, or organic matter was nonsignificant between the covered and non-covered treatments in any year. Leaf N content was 11% to 16% greater with the covered treatment compared with the non-covered treatment in 2002 and 2003, but leaf N was similar for the two treatments in 2001. Leaf P content was similar for the two treatments in 2001, but was about 36% less with the covered treatment than the non-covered treatment in 2002 and 2003. Leaf Ca content was decreased by 11% to 17% due to a synthetic fabric cover in 2002 and 2003. Leaf Mg content was 13% to 24% less with the covered treatment than the non-covered treatment in 2002 and 2003. However, the decreased leaf P, Ca, and Mg contents with the covered trees were due to the dilute effects of increased tree growth. The effects of a fabric cover on leaf K, S, B, Zn, Mn, and Cu contents were primarily nonsignificant. Our results suggest that although nutrient availability in the soil is not reduced by a wide synthetic fabric cover, higher rates of fertilizers may be needed for the covered sweet cherry trees due to the elevated tree growth and fruit production from a long-term perspective.
(16) Fruit Quality of the USDA Opuntia sp. Germplasm Collection
Authors: Jenderek Maria M. , Hellier Barbara
Published: February 2019

The fruit of several Opuntia species (prickly pear) are a good source of calcium, potassium, and ascorbic acid and are consumed fresh or processed as juices or preserves. Plants of Opuntia may be grown in arid and semiarid environments on marginal soils. Various cultivars, particularly in the species Opuntiaficus-indica, are grown commercially in the United States, Israel, Italy, Mexico, and South Africa. There is a need for new sources of genetic diversity and subsequent germplasm evaluation, and until recently, no publicly maintained germplasm collection of Opuntia existed in the United States. The purpose of this study was to evaluate fruit quality of 25 Opuntia accessions, originating from six countries, and maintained at the USDA collection at the National Arid Land Plant Genetic Resource Unit, Parlier, Calif. The largest fruits were harvested from plants of accessions PARL 201, 202, and 228 (227.6, 247.3, and 231.3 g/fruit, respectively). The hardest peel was on fruits of PARL 225 and 234 (both 3.7 kg), and fruit pulp of the same two accessions had the highest firmness (2.3 and 2.4 kg, respectively). Soluble solids in mature fruit varied from 6.1% (PARL 231) to 15.0% (PARL 254). The fruit color ranged from light yellow through orange, pink to dark purple. These characteristics and other traits such as fruit acidity, presence of spines, and seed mass/fruit indicated that the material represents a diverse germplasm collection, usable for future cultivar development.
(378) Weed Management in Organic Grapes
Authors: Delate Kathleen , McKern Andrea , Kirkland Michelle
Published: February 2019

Iowa was the sixth largest producer of grapes in the United States in the early 1900s, with 24,000 ha under production. The rapid expansion of petrochemicals post-World War II and grape's sensitivity to 2,4-D herbicides reduced vineyard size in Iowa to 28 ha in 2001. Recent state governmental support for organic fruit research and viticulture in general has led to the expansion of the grape and wine industry in Iowa. As of 2001, 5883 ha of organic grapes were produced in the United States. Challenges to organic grape production in the Midwest include diseases and weeds. The cultivation of American grape cultivars is essential in organic viticulture in the Midwest, including cultivars that are relatively cold hardy and disease tolerant. From 2003 to 2004, we experimented on-farm at Kirkland Vineyards, Norwalk, Iowa, with methods of organically approved weed management. Three replications of plots consisting of five vines each of `Marechal Foch' were laid out in 2003 in a completely randomized design in a 1-year-old vineyard. Treatments consisted of wood chips, wood chips plus vinegar herbicide (All-Down™, Summer Set Co., Chaska, Minn.), and mowing when weeds and groundcover reached 15 cm. Wood chips decreased weed load significantly over mowing alone, but wood chips plus vinegar herbicide provided the most control over 2 years of the experiment. There was a trend toward greater plant height in the wood chip treatment, but no significant differences in plant height were observed among treatments.