bluuebunny/crossref_metadata_2025 huggingface dataset:
In Vitro Fungicidal Activity of Calcium and Potassium Salts on Several Commercially Significant Plant Pathogens
Authors: Kaiser Clive , Hamm Philip B. , Gieck Stacy , David Nicholas , Long Lynn , Meland Mekjell , Christensen J. Mark
Published: February 2019

In vitro dose responses of several calcium and potassium salts were determined on some commercially significant plant pathogens, including: Helminthosporium solani, Fusarium oxysporum f. sp. pisi race 2, Colletotricum coccodes, Phytophthora cactorum, Phytophthora cinnamomi, Phytophthora erythroseptica, Phytophthora infestans, Phytophthora megasperma, Pythium ultimum, and Venturia inaequalis. Mycelial growth inhibition was both salt-specific and dose-related. Pythium ultimum was completely inhibited by 75 mg·L−1 or greater calcium propionate, but needed 300 mg·L−1 or greater of calcium acetate and 40 mL·L−1 or greater of potassium silicate for complete inhibition. Phytophthora infestans was completely inhibited by 150 mg·L−1 or greater calcium acetate, 150 mg·L−1 or greater calcium propionate, or 5 mL·L−1 or greater potassium silicate. Phytophthora cactorum was completely inhibited by 300 mg·L−1 or greater calcium propionate, but required 600 mg·L−1 or greater calcium acetate and 10 mL·L−1 or greater potassium silicate for complete inhibition. Phytophthora cinnamomi was completely inhibited by calcium propionate at 600 mg·L−1 or greater or by 10 mL·L−1 or greater potassium silicate. Only potassium silicate inhibited Phytophthora megasperma, Phytophthora erthroseptica, V. inequalis, and H. solani at concentrations of 5 mL·L−1 or greater, 20 mL·L−1 or greater, 40 mL·L−1 or greater, or 80 mL·L−1 or greater, respectively. Potassium acetate did not completely inhibit any of the pathogens in this study when tested at concentrations 1200 mg·L−1 or less.
Influence of Packaging on Quality Retention of Longans (Dimocarpus longan) Under Constant and Fluctuating Postharvest Temperatures
Authors: Wall Marisa M. , Nishijima Kate A. , Keith Lisa M. , Nagao Mike A.
Published: February 2019

Longan (Dimocarpus longan) fruit production and global exports are rapidly expanding. Consumer acceptance of this high value crop requires that fruit arrive in excellent condition. Pericarp browning and fungal diseases are the main postharvest problems for longans. Research was conducted to establish optimum storage temperatures and packaging systems to retain fruit quality of ‘Biew Kiew’ longans. Average respiration rates for longans stored at 20 °C (61.6 mg CO2/kg/h) were about twice the rate as those stored at 10 °C (32.7 mg CO2/kg/h) and triple the rate for those stored at 5 °C (21.1 mg CO2/kg/h). Ethylene rates were below 0.4 μg·kg−1·h−1. Fruit quality and shelf life were greatest when stored at 10 °C. Longans held at 20 °C were unmarketable after 10 d, and fruit stored at 5 °C exhibited chilling injury (CI). After storage at 10 °C, longans packaged in microperforated (MP) bags, clamshell (CL) containers, or Peakfresh® film (PF) had the highest visual quality ratings, lowest disease incidences, and longest shelf life when compared with fruit in Lifespan® film (LS) or fiberboard boxes. The most promising packages (MP, CL, PF) were evaluated further under constant 10 °C or simulated shipping (SS) conditions with fluctuating temperatures (22 °C/10 °C/22 °C). Longans in CL containers had the highest visual quality and lowest disease incidence when stored at 10 °C, but there were no differences among package treatments under SS conditions. Also, sensory ratings were greatest for fruit packed in CL or PF when stored at 10 °C but all sensory scores decreased under SS temperatures. When longans were stored under fluctuating temperatures, aril texture and flavor ratings were highest for CL packages. CL, PF, and MP are suitable packages for longans stored under optimal temperatures. However, for longans stored under SS conditions, sensory quality was highest when packaged in CL containers.
Estimation of Certain Physical and Chemical Fruit Characteristics of Various Cherry Laurel (Laurocerasus officinalis Roem.) Genotypes
Authors: Celik Ferit , Ercisli Sezai , Yilmaz Suzan O. , Hegedus Attila
Published: February 2019

Fruits of 11 cherry laurel (Laurocerasus officinalis L.) genotypes grown in a single location, Rize province, were analyzed for their fruit characteristics. Both physical and chemical characteristics of cherry laurel fruits were significantly influenced by genotypes. Fruit weight, the number of fruits per cluster, and flesh per seed ratio ranged between 1.87 and 4.01 g; 9.21 and 21.05, and 5.54 and 9.33, respectively. The genotypes R06 and R09 had the highest total anthocyanin [205 and 202 mg/100 g fresh weight (FW), respectively] and R06 and R11 had the highest total phenolic contents (503 and 481 mg/100 g FW, respectively). Total carotenoid and vitamin C contents ranged from 207 to 278 mg/100 g FW and 2.1 to 4.1 mg/100 g FW, respectively. Soluble solid content (SSC), crude fiber, crude protein, pectin, ash, and pH of genotypes fell between 9.64% and 17.10%; 0.44% and 0.85%; 1.44% and 2.09%; 0.20% and 0.47%; 0.25% and 0.71%, and 4.30 and 4.93, respectively. Data demonstrated that the great variations observed in the physical and chemical characteristics of individual cherry laurel genotypes might be explained by genotypic effect because all genotypes grew under the same ecological conditions. The investigated genotypes seemed to be perspective in health promotion.
Application of the Abscission Agent 5-Chloro-3-methyl-4-nitro-1H-pyrazole Does Not Affect Peel Integrity or Postharvest Decay of Mechanically Harvested Late-season Fruit of ‘Valencia’ Orange during the Normal Commercial Harvest-to-processing Period
Authors: Spann Timothy M. , Pozo Luis V. , Kostenyuk Igor , Burns Jacqueline K.
Published: February 2019

In Florida, the combined use of mechanical harvesters and the abscission agent 5-chloro-3-methyl-4-nitro-1H-pyrazole (CMNP) for late-season harvesting (May to June) of fruit of ‘Valencia’ orange is effective at removing mature fruit with minimal adverse effects on the subsequent season's crop. However, CMNP can cause fruit peel scarring, and no data were available on how this affects peel integrity and potential losses resulting from fruit crushing and/or decay before processing. In this study, two late-season harvest dates were tested in commercial orchards during 2009 and 2010. Harvesting treatments consisted of combinations of two mechanical harvester ground speeds (0.8 and 1.6 km·h−1), two harvester shaker head frequencies (185 and 220 cycles/min), and CMNP foliar applications (4 days before harvesting) at 250 and 300 mg·L−1 in a spray volume of 2810 L·ha−1 plus mechanically-harvested and hand-picked controls. After harvesting, fruit samples were randomly collected from each block for peel resistance and postharvest decay evaluations. Peel resistance was determined by measuring both peel puncture force and fruit crush force. Fruit used to study postharvest decay were stored at 27 °C and 50% relative humidity or ambient conditions and evaluated daily for 8 days. Peel resistance was unaffected by mechanical harvesting combinations or CMNP application. No significant effects on postharvest decay were found among treatments for at least 3 days after harvest. However, a significant increase in postharvest decay between CMNP-treated and untreated fruit began between 4 and 6 days after harvest such that by 8 days after harvest, decay was as high as 25% in CMNP-treated fruit. The results indicate that CMNP can be safely used in combination with late-season mechanical harvesting under the conditions described in this study without losses resulting from fruit crushing or decay for at least 3 days, a time period well within the normal commercial harvest-to-processing time of ≈36 h.
Micropropagation of Mahonia ‘Soft Caress’
Authors: Rounsaville Todd J. , Touchell Darren H. , Ranney Thomas G. , Blazich Frank A.
Published: February 2019

Mahonia ‘Soft Caress’ is a unique new cultivar exhibiting a compact form and delicate evergreen leaves. Protocols for micropropagation of M. ‘Soft Caress’ were developed to expedite multiplication and serve as a foundation for future work with other taxa of Mahonia Nutt. Combinations of sucrose at 30 or 45 g·L−1 in conjunction with Gamborg B5 (B5), Quoirin and Lepoivre (QL), and Murashige and Skoog (MS) basal media as well as other selected growth regulator treatments were evaluated as multiplication media. Rooting of microcuttings was conducted in vitro using combinations of indole-3-butyric acid (IBA) at 0, 2, 4, 8, or 16 μM under either light or dark. Quick dip treatments with aqueous solutions of the potassium (K) salt (K-salt) of IBA at 0, 5.2, 10.4, 20.7, or 41.4 μM were tested in a second experiment for ex vitro rooting. Media containing B5 basal salts and vitamins supplemented with sucrose at 30 g·L−1, 5 μM 6-benzylaminopurine, 5 μM kinetin, 0.5 μM indole-3-acetic acid, and 2.5 μM gibberellic acid yielded 2.80 ± 0.14 microshoots with a mean length of 14.76 ± 0.63 mm over a 6-week culture period and was an optimal multiplication media. Light treatment and IBA concentration had a significant effect on rooting percentages. Microcuttings treated with 8 μM IBA and maintained in the dark resulted in the best rooting (70%) and ex vitro establishment.
Evaluation of Salinity Tolerance of Prairie Junegrass, a Potential Low-maintenance Turfgrass Species
Authors: Wang Sheng , Zhang Qi , Watkins Eric
Published: February 2019

Prairie junegrass (Koeleria macrantha) is a perennial, cool-season, native grass that has shown potential for use as a turfgrass species in the northern Great Plains; however, limited information is available on its salt tolerance. In this study, salinity tolerance of four junegrass populations from North America (Colorado, Minnesota, Nebraska, and North Dakota) and two improved turf-type cultivars from Europe (‘Barleria’ and ‘Barkoel’) was evaluated and compared with kentucky bluegrass (Poa pratensis), perennial ryegrass (Lolium perenne), sheep fescue (Festuca ovina), hard fescue (F. brevipila), and tall fescue (F. arundinacea). Salinity tolerance was determined based on the predicted salinity level causing 50% reduction of final germination rate (PSLF) and daily germination rate (PSLD) as well as electrolyte leakage (EL), tissue dry weight (DW), and visual quality (VQ) of mature plants. All populations of prairie junegrass showed similar salt tolerance with an average of PSLF and PSLD being 7.1 and 5.3 g·L−1 NaCl, respectively, comparable to kentucky bluegrass and hard and sheep fescue but lower than tall fescue and perennial ryegrass. Larger variations were observed in VQ in the junegrasses compared with EL and DW, in which ‘Barleria’ from the European population showed the highest VQ, following two salt-tolerant grasses, tall fescue and sheep fescue. Nebraska population was the least salt-tolerant within the species but still exhibited similar or higher tolerance than kentucky bluegrass and perennial ryegrass cv. Arctic Green. Overall, junegrass was more salt-sensitive during germination but more tolerant to salinity when mature. Salinity tolerance of junegrass may be further improved through turfgrass breeding because salinity tolerance varied in different populations.
Colonization of Citrus and Citrus-related Germplasm by Diaphorina citri (Hemiptera: Psyllidae)
Authors: Westbrook Catherine J. , Hall David G. , Stover Ed , Duan Yong Ping , Lee Richard F.
Published: February 2019

Huanglongbing (HLB) is a serious and devastating disease of citrus caused by Candidatus Liberibacter spp. and vectored by the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). The disease has the potential to greatly limit the production of citrus in Florida and other citrus-growing regions worldwide. Current control of D. citri and HLB is inadequate, but the identification and incorporation of D. citri resistance traits from uncultivated Citrus spp. and Citrus relatives is seen as a potential disease management strategy. In this study, seedlings of 87 Rutaceae seed-source genotypes, primarily in the orange subfamily Aurantioideae, were assessed in the field for their propensity in a free-choice situation for infestations of natural south Florida populations of D. citri. The majority of test populations surveyed hosted all three life stages of D. citri; however, there were significant differences among the test populations in the mean ranks for D. citri eggs (F = 3.13, df = 86, P < 0.0001), nymphs (F = 9.01, df = 86, P < 0.0001), and adults (F = 4.21, df = 86, P < 0.0001). The only sampled test population that was completely avoided by all life stages of D. citri was seedlings of Casimiroa edulis Llave et Lex, commonly known as white sapote, which was one of the few plants included in the study belonging to the Rutaceae subfamily Toddalioideae. Although not completely avoided, very low levels of D. citri were found on two surveyed test populations of Poncirus trifoliata (L.) Raf, seedlings of ‘Simmon's trifoliate’ and ‘Little-Leaf’. Poncirus trifoliata, the trifoliate orange, readily forms hybrids with Citrus spp., is commonly incorporated into rootstock varieties, and has been used in breeding-advanced scion material. The identification of partial resistance in P. trifoliata to D. citri could prove useful in future citrus breeding efforts aimed at reducing the incidence and spread of HLB. Determining if there is true resistance to D. citri in this and other germplasm sources with a low propensity for infestations in free-choice situations will require no-choice experiments.
Fertilizer Composition, Concentration, and Irrigation Method Affect Growth and Development of Oxalis regnellii and O. triangularis
Authors: Miller Chad T. , Mattson Neil S. , Miller William B.
Published: February 2019

Oxalis regnellii, the shamrock plant, and O. triangularis are niche ornamental greenhouse crops produced and marketed primarily for their foliage; thus, it is imperative to produce the fullest, most colorful, and blemish-free plants as possible. An experiment was conducted using O. regnellii, comparing two irrigation methods, overhead (drip) irrigation versus subirrigation, in addition to varying 20N–2.2P–16.6K fertilizer concentrations, 50, 100, 200, 300, and 500 mg·L−1 nitrogen (N). Overhead irrigation produced larger plants with increased root mass as compared with subirrigation. Low or high fertilizer concentration (50 mg·L−1 N and 500 mg·L−1 N, respectively) led to reductions in the fresh and dry weight of overhead-irrigated plants compared with intermediate fertilizer rates. At the highest fertilizer treatment, plant height was decreased. Chlorophyll index (based on SPAD readings) increased linearly and quadratically for subirrigated and overhead-irrigated plants, respectively. A second study analyzed the effects of seven different fertilizer formulations on growth of O. regnellii and O. triangularis. The fertilizers used in this study were Jack's LX All Purpose (21N–2.2P–16.6K), Peter's Professional (20N–8.8P–16.6K), Jacks Poinsettia FeED Ca-Mg (15N–1.7P–12.5K), Jack's Petunia FeED Mg (20N–1.3P–15.7K), Peter's Professional Peat-Lite Dark Weather Feed (15N–0P–12.5K), Peter's Excel Cal-Mag (15N–2.2P–12.5K), and the slow-release fertilizer Osmocote® (14N–4.2P–11.6K). Growth of both species was significantly reduced by fertilizers that contained little or no phosphorus (P). Current water-soluble fertilizer recommendations of 21N–2.2P–16.6K or slow-release granule fertilizer of 14N–4.2P–11.6K (Osmocote®) produced acceptable, marketable plants, whereas the best O. regnellii and O. triangularis plants were produced using 15N–2.2P–12.5K and 20N–1.3P–15.7K formulations, likely as a result of the additional calcium (Ca), magnesium (Mg), and iron (Fe) in the mixtures.
Early Navel Orange Fruit Yield, Quality, and Maturity in Response to Late-season Water Stress
Authors: Kallsen Craig E. , Sanden Blake , Arpaia Mary Lu
Published: February 2019

The objective of this study was to measure effects of late-season water stress on fruit yield, size, quality, and color of an early-maturing navel orange cultivar, Citrus sinensis (L.) Osbeck ‘Beck-Earli’. Three irrigation regimes were initiated in August in the southern San Joaquin Valley of California in 2006, 2007, and 2008. Increasing levels of water stress resulted in decreasing midday shaded leaf water potential (SLWP) ranging from –1.4 MPa in early September to a minimum of –2.5 MPa at harvest. Generally, over the course of the 3 years, late-season water stress decreased fruit grade and increased soluble solids concentration (SSC), titratable acidity (TA), the BrimA index, and orange color. Fruit juiciness and SSC:TA ratios were unaffected by late-season water stress. The intensity of the water stress in 2007 decreased fruit yield by number and weight and decreased the percentage of large fruit. When trees exposed to 2 years of late-season water stress were fully irrigated the next year, fruit yield and quality were similar to trees that had not experienced late-season water stress for the 3 years of the study.
Long-term Effects of Four Groundcover Management Systems in an Apple Orchard
Authors: Atucha Amaya , Merwin Ian A. , Brown Michael G.
Published: February 2019

Groundcover management systems (GMSs) are essential for fruit production, but very few long-term studies have evaluated orchard GMS sustainability. We evaluated four GMSs—pre-emergence soil-active herbicides (PreHerb), post-emergence herbicide (PostHerb), a turfgrass cover crop (Sod), and hardwood bark mulch (Mulch)—in an apple (Malus domestica Borkh.) orchard over 16 years of continuous observation. There were no consistent long-term trends in fruit yields among GMSs, although during the first 5 years, yields were lower in trees on Sod. Tree growth was greater in PostHerb and Mulch than in Sod during the first 5 years, and during the next decade, trees in Mulch plots were consistently larger than in other GMSs. Total soil nitrogen (N) and carbon (C) content, C-to-N ratios, and essential plant nutrients were much greater in the Mulch soil after 16 years of treatments. Long-term responses of trees to groundcover vegetation indicated that apple trees respond adaptively to compensate for weed and grass competition. Year-round elimination of surface vegetation with residual soil active herbicides may be unnecessary or even detrimental for orchard productivity and soil fertility in established orchards. Post-emergence herbicides that reduce weed competition primarily during the summer months may offer an optimal combination of weed suppression and soil conservation.
Nitrogen Dynamics and Nutrient Budgets in Four Orchard Groundcover Management Systems
Authors: Atucha Amaya , Merwin Ian A. , Purohit Chandra K. , Brown Michael G.
Published: February 2019

Excessive nitrogen (N) applications can increase surface and water contamination, and leaching losses may occur when N fertilizer rates are too high relative to crop demands and soil N availability. Quantifying nutrient inputs, cycling, and outputs from orchards provides a method to measure surplus of nutrients, particularly N, that may leach or runoff. We conducted a long-term study to develop N budgets based on observed nutrient dynamics under four groundcover management systems (GMSs) with and without N fertilization. Four GMS treatments were randomly assigned to 12 plots and maintained since 1992 in 2-m-wide strips within tree rows: pre-emergence residual herbicide (PreHerb), post-emergence herbicide (PostHerb), mowed-sod (Sod), and hardwood bark mulch (Mulch). We measured system N inputs in fertilizer, mulch biomass, rain, and irrigation water; N outputs in harvested fruit, surface runoff, and subsurface leaching; and internal N cycling from surface vegetation, soil mineralization, leaf fall, and pruned wood. For the year with N fertilizer (2005), the overall N balance was positive (inputs exceeded outputs) in all GMSs but greater in the PostHerb and Mulch treatments. In the year without N fertilizer (2007), the overall N balance was negative for PreHerb and PostHerb and positive for Mulch and Sod treatments. Soil mineralization and recycling groundcover biomass accounted for greater than 60% of internal N fluxes, and harvested fruit represented greater than 70% of N outputs from the system during both years. During the year with N fertilizer, N losses were 1% to 4% and 18% to 22% through surface runoff and subsurface leaching, respectively. During the year without fertilizer, surface runoff N losses were twice the subsurface leaching N losses in all GMSs.
Evaluating Winter-sown Onion Entries for Iris yellow spot virus Susceptibility
Authors: Mohseni-Moghadam Mohsen , Cramer Christopher S. , Steiner Robert L. , Creamer Rebecca
Published: February 2019

Iris yellow spot virus (IYSV) causes a foliar disease in onion (Allium cepa L.) that results in a reduction in bulb size. Currently, no IYSV-tolerant or -resistant cultivar exists and a genetic source for tolerance or resistance has not been identified. Because other disease control methods are limited, host plant resistance offers the best hope to combat this disease. In this study, 13 winter-sown onion entries were screened for iris yellow spot (IYS) symptoms during the 2007 and 2008 cropping seasons. Twenty plants from each plot were observed and rated weekly during the growing seasons for straw-colored, necrotic lesions, typical of IYSV infection. Collected plant samples were assayed for IYSV by enzyme-linked immunosorbent assay (ELISA) and reverse-transcription polymerase chain reaction (RT-PCR). Visual rating was done using a scale of 1 to 9 with 1 representing no symptomatic tissue and 9 representing more than 50% tissue damage. Two different plant sampling methods were used in disease rating to determine their effect on mean severity and to correlate disease severity with absorbance values. Of the entries tested, plants of NMSU 05-33-1 exhibited a delay in symptom expression and lower IYSV levels relative to plants of other entries. Plants of ‘Denali’ and ‘Gelma’ appeared to be more susceptible to IYSV than plants of other entries. Plant selection within the plot over time did not influence disease rating values. When the same plants were rated and sampled for IYSV using ELISA, there was a strong, positive correlation between rating and absorbance values.
May Soil Solarization Reduce the Juvenile Period in Olive?
Authors: El Riachy Milad , Rallo Luis , de la Rosa Raúl , León Lorenzo
Published: February 2019

The duration of the juvenile period (JP) before the seedlings reach the adult phase (AP) and begin flowering is the major impediment for fruit breeding in olive. In this work, the effect of soil solarization on the growth and duration of the JP of olive seedlings was studied. Seedlings obtained from open pollination of ‘Manzanilla de Sevilla’ and from crosses between ‘Arbequina’ × ‘Arbosana’ and ‘Picual’ × ‘Koroneiki’ were tested. Solarization treatment consisted on covering the soil around the trees for 3 years by black plastic film in a split-plot design with the three progenies as the main factor and solarization/not solarization as the secondary factor. Solarization resulted in both higher soil temperature and soil moisture in solarized plots with respect to non-solarized. Significant differences between crosses were found for plant vigor and flowering measurements throughout the experiment. Soil solarization increased trunk diameter and the number of seedlings reaching AP in ‘Manzanilla’ open progeny. A positive effect of solarization on flowering index was also observed in ‘Picual’ × ‘Koroneiki’ progenies. These results suggest that soil solarization may be recommended as a tool for shortening the duration of the JP and thus accelerating the selection process in olive breeding programs.
Foliar Application of Abscisic Acid Induces Dormancy Responses in Greenhouse-grown Grapevines
Authors: Zhang Yi , Mechlin Tracey , Dami Imed
Published: February 2019

The purpose of this study was to investigate the influence of foliar application of abscisic acid (ABA) on grapevine dormancy, specifically to: 1) determine the optimum foliar application concentration of ABA and 2) evaluate the morphological and physiological changes of greenhouse-grown grapevines in response to exogenous ABA application. Vitis vinifera ‘Cabernet Franc’ and Vitis spp. ‘Chambourcin’ with different leaf ages (40, 50, 80, 100, 110, and 120 days) were subjected to foliar ABA application at different concentrations (0, 100, 200, 400, 600, 800, 1600, and 3200 mg·L−1) and to a cold-acclimated regime. Concentrations of 800 mg·L−1 or higher were phytotoxic and the optimum concentrations were between 400 and 600 mg·L−1. Optimum concentrations of ABA inhibited shoot growth and advanced growth cessation, periderm formation, and leaf senescence, which led to advanced dormancy in both cultivars. In this study, it was concluded that exogenous ABA induced endodormancy because single cuttings (not paradormant) under favorable growing conditions (not ecodormant) were used. Furthermore, grapevine response to ABA was influenced by leaf age and cold treatment. ABA was effective in inhibiting shoot growth and increasing periderm formation in the young vines with 40- to 50-day old leaves and the old grapevines with 80- to 120-day old leaves. However, ABA was effective in inducing early shoot cessation, leaf senescence and abscission, and dormancy in old vines with 100- to 120-day old leaves only. The advanced morphological and physiological changes induced by exogenous ABA mimicked those triggered by environmental cues during the cold acclimation process. It was suggested that advancing the cold acclimation process using foliar ABA application may be beneficial for long-season grape cultivars grown in regions with short growing seasons and early fall frost events.
Rabbiteye Blueberry Postharvest Fruit Quality and Stimulation of Ethylene Production by 1-Methylcyclopropene
Authors: MacLean Dan D. , Scott NeSmith D.
Published: February 2019

A postharvest 1-methylcyclopropene (1-MCP) treatment was evaluated for its ability to maintain firmness and delay the ripening of rabbiteye blueberries. Three cultivars, Austin, Brightwell, and Premier, were harvested by hand from the UGA Alapaha Blueberry Farm and treated overnight with 1 μL·L−1 1-MCP as field heat was being removed [0 to 1 °C, 90% to 95% relative humidity (RH)]. Fruit were evaluated for firmness, total soluble solids (TSS), total acidity (TA), ethylene production, and other quality attributes at 0, 1, and 2 weeks after harvest as well as 1 or 4 days post-removal evaluations at room temperature (≈21 °C). In general, the 1-MCP treatment resulted in the stimulation of ethylene production in all three cultivars but had minimal effect on TSS and TA content. Furthermore, the treatment resulted in an accelerated loss of firmness in ‘Brightwell’. The lack of inhibition of fruit ripening likely related to the fact that blueberries were harvested, and subsequently treated with 1-MCP, at a post-climacteric stage of development. Based on current results, more information is required regarding ethylene production during rabbiteye blueberry fruit maturation before establishing a 1-MCP treatment recommendation for use by the rabbiteye blueberry industry.
A Laboratory Device for Continual Measurement of Water Retention and Shrink/Swell Properties during Drying/Wetting Cycles
Authors: Qi Guifang , Michel Jean-Charles , Boivin Pascal , Charpentier Sylvain
Published: February 2019

The precise measurement of the water retention and shrink/swell properties of growing media or soil over time is important for the effective management of irrigation and fertilization. A new apparatus was developed for simultaneously and continuously measuring the water retention and shrink/swell properties of growing media during several drying/wetting cycles with varying intensities (0↔–5 kPa, 0↔–10 kPa, 0↔–32 kPa). The measurements on slightly decomposed Sphagnum peat showed encouraging results. Regardless of the intensity of drying, water retention and shrink/swell properties are mainly modified after the first drying process, resulting in degradation of density and water retention, whereas these properties are unaffected by the other cycles, even if hysteresis phenomena are always shown to take place. Variations in drying intensity reveal different physical behaviors with an inflection point observed (i.e., a change in physical behavior) for the shrink/swell and water retention curves for the highest intensity tested (from –20 kPa).
Effects of Wastewater Sludge Topdressing on Color, Quality, and Clipping Yield of a Turfgrass Mixture
Authors: Bilgili Ugur , Olcay Topac-Sagban F. , Surer Irfan , Caliskan Nejla , Uzun Pervin , Acikgoz Esvet
Published: February 2019

The objectives of the present study were to determine the effects of the rate and timing of the application of sun-dried wastewater sludge from a food processing company's wastewater system on turfgrass growth and quality. The results were compared with those obtained with ammonium nitrate, and changes in the concentration of heavy metals and the presence of fecal coliform in turf soils after sun-dried wastewater sludge application were determined. The rate and the timing of sun-dried wastewater sludge and ammonium nitrate applications affected the turf color, quality, and clipping yield. Monthly fertilization resulted in a more uniform color and turf quality than infrequent spring and fall fertilization. Compared with the background values of base soils, heavy metals did not accumulate in sun-dried wastewater sludge-amended soils over the test period. Fecal coliform was not detected in sludge-amended soil samples, indicating that bacteria regrowth did not occur during the study period.
Physiological Responses of Turfgrass Species to Drought Stress under High Desert Conditions
Authors: Leksungnoen Nisa , Johnson Paul G. , Kjelgren Roger K.
Published: February 2019

Broad concerns over water shortages and drought where irrigated urban landscapes are common in high desert regions have focused attention on drought tolerance of turfgrass species. We investigated the physiological responses of kentucky bluegrass (KBG) and tall fescue (TF) under a prolonged drought under high desert conditions. The experimental design was a split plot with three replicates. Two irrigation treatments as a whole plot—well-watered and no water—were applied to subplots of ‘Midnight’ KBG and ‘Gazelle’ TF. Stomatal conductance (gS), canopy temperature, and predawn leaf water potential were measured over two seasons. KBG gS and leaf water potential decreased faster and to a greater extent than TF in response to soil drying, and KBG was in complete dormancy and brown within 5 weeks after cessation of irrigation. By contrast, TF maintained a green canopy throughout the drought periods. In the no-water plots, TF appeared to consume water from the deepest measured soil profiles (80- to 100-cm depth), whereas KBG used most of the water in the 50- to 60-cm depths. When watered for recovery in late summer, KBG plots were mostly green within 3 weeks after rewatering. The surface temperature of the well-watered plots was 6–13 °C cooler than the no-water plots and TF showed 5–7 °C lower temperature than KBG in no-water plots. TF is suitable for deep soil, exploiting a larger volume of water to avoid drought, whereas KBG's rapid drought avoidance would likely perform better in shallow landscape soils under drought.
Implementation of Bar-code Technology in a Tree Fruit Breeding Program
Authors: Evans Kate M. , Brutcher Lisa J. , Konishi Bonnie S.
Published: February 2019

Inventory control of trees and fruit samples in the Washington State University apple breeding program has been simplified by the use of bar codes. Tree labels incorporate individual bar-coded identities that can be scanned in the field when taking measurements or collecting samples. Bar codes on fruit sample labels also simplify data recording as well as improve the efficiency of the program by greatly reducing the risk of errors. The interface of bar-code identities with data organization and statistical software makes data analysis more straightforward.
Germination In Vitro, Micropropagation, and Cryogenic Storage for Three Rare Pitcher Plants: Sarracenia oreophila (Kearney) Wherry (Federally Endangered), S. leucophylla Raf., and S. purpurea spp. venosa (Raf.) Wherry
Authors: Northcutt Cameron , Davies Daniel , Gagliardo Ron , Bucalo Kylie , Determann Ron O. , Cruse-Sanders Jennifer M. , Pullman Gerald S.
Published: February 2019

The genus Sarracenia forms a group of carnivorous pitcher plants native to North America. Habitat destruction and overcollection have caused pitcher plants to become rare, including U.S. federally endangered S. oreophila as well as S. leucophylla and S. purpurea spp. venosa (Raf.) Wherry, both listed as endangered in several states. Protocols for in vitro germination, sustainable shoot micropropagation, shoot establishment in soil, and seed cryopreservation are presented. Six-min sulfuric acid scarification treatments coupled with appropriate tissue culture media resulted in germination in vitro within 3 weeks, often reaching greater than 50%. Best germination for S. leucophylla and S. purpurea occurred on one-third strength Murashige and Skoog (MS) salts, whereas S. oreophila germinated best on one-sixth strength MS salts. Adjustment of pH to 4.5 to simulate a bog environment further increased germination for S. leucophylla. Shoot multiplication occurred at optimal levels when explants were placed on media in the presence of a cytokinin without auxin with greatest multiplication on 6-benzylaminopurine (BAP) or trans-zeatin and best shoot quality on trans-zeatin. Plant establishment in soil required both an in vitro rooting treatment and use of shoot clusters resulting in greater than 80% survival in soil. Seed cryopreservation tests with all three species suggest storage in liquid N2 followed by in vitro micropropagation and plant establishment can be used to preserve material long term.
Regeneration of Anthurium andraeanum from Leaf Explants and Evaluation of Microcutting Rooting and Growth under Different Light Qualities
Authors: Gu Aisu , Liu Wenfang , Ma Chao , Cui Jin , Henny Richard J. , Chen Jianjun
Published: February 2019

This study established a new method for regenerating Anthurium andraeanum Lind. and evaluated effects of different wavelengths from light-emitting diodes (LEDs) on rooting and growth of adventitious shoots. Callus occurred in leaf explants of A. andraeanum ‘Alabama’ and ‘Sierra’ cultured on a modified Murashige and Skoog (MS) basal medium supplemented with four concentrations of N-phenyl-N′-1,2,3-thiadiazol-5-ylurea (TDZ). Adventitious shoots were induced from callus pieces (≈1 cm3) cultured on the modified MS medium containing 6-benzyladenine (BA) with kinetin (KN), BA, and/or KN with 3-indolebutyric acid (IBA) or α-naphthalene acetic acid (NAA). Results showed that 1.82 μM TDZ induced 83.3% and 77.8% of leaf explants of ‘Alabama’ and ‘Sierra’ to produce callus and 24.9 and 24.7 adventitious shoots were produced per callus piece of ‘Alabama’ and ‘Sierra’ cultured on the modified MS medium containing 0.89 μM BA, 2.32 μM KN, and 0.98 μM IBA, respectively. Adventitious shoots were cut and rooted in the modified MS medium containing 0.98 μM IBA and grown under the same light level but with different light qualities. All adventitious shoots rooted; root numbers, root lengths, root fresh and dry weights, and leaf area of plantlets grown under red plus blue light were comparable to those grown under conventional fluorescent white light. Shoot height was the greatest in monochromic blue light followed by red light. Shoot fresh and dry weights of plantlets grown under red plus blue light, however, were significantly greater than those grown under the other light qualities. Plantlets grown under red plus blue light had 22.7% greater total dry weight and more balanced root-to-shoot ratio than those grown under fluorescent white light. These results suggested the use of complex of red plus blue LED could be an option for improving growth of A. andraeanum plantlets in vitro.
A Hard Nut to Crack: Macadamia in Hawaii
Authors: Rietow David
Published: February 2019

The macadamia nut (Macadamia integrifolia) was introduced to Kapulena on the Hamakua Coast of Hawaii from Australia in 1881 by William Purvis. The first commercial plantation was established in Oahu but the commercial industry moved to Hawaii, the Big Island. By 1950, the largest producer was the Honakaa Sugar Company with 450 acres (182 ha). The development of new technology, including the selection of cultivars on grafted trees, resulted in an expansion of the industry. The Mauna Loa Company is now the world’s largest grower, processor, and marketer of macadamia nuts with over 10,000 acres (4047 ha). The industry now consists of ≈500 to 600 growers that are connected by ownership or contract to the two largest processor/marketers, Mauna Loa and Mac Farms. The Hawaiian macadamia industry is now relatively static. Crop area peaked in 1990 at 22,600 acres (9146 ha) and then gradually dropped to 17,000 acres (6880 ha) in 2006 where it has remained. In-shell nut production during the same period ranged from a low of 40 million pounds (18,148 t) in this past crop year (2010–11) to a high of 58 million pounds (26,315 t) in 2006–07. Competition among Hawaii, Australia, and Africa is now intense.
Yield of Japanese Tomato Cultivars Has Been Hampered by a Breeding Focus on Flavor
Authors: Higashide Tadahisa , Yasuba Ken-ichiro , Suzuki Katsumi , Nakano Akimasa , Ohmori Hiromi
Published: February 2019

The yield of greenhouse tomatoes in Japan has not increased since the 1980s and remains much less than 30 kg·m−2 per year. To investigate the cause of this low yield, we compared six Japanese tomato cultivars that were commonly grown or released during the past 80 years to see whether fruit yield (fruit fresh weight per area) and dry matter (DM) content per fruit improved under current cultivation conditions. Fruit yield in ‘Momotaro’ (released in 1985) was lower than that in older cultivars. Total DM was determined mainly by light use efficiency and photosynthetic rate, and light use efficiency was correlated with maximum photosynthetic rate. The more modern cultivars did not show improved DM content per fruit. The DM content per fruit was strongly correlated with the soluble solids content in fruits except in ‘Momotaro’ and ‘Momotaro colt’, but soluble solids in fruits of the ‘Momotaro’-type cultivars were higher than in other cultivars for a given DM content per fruit. Thus, tomato breeding in Japan appears to have focused on fruit soluble solids content per unit DM rather than fruit yield or DM content; as a result, only the former parameter has improved greatly.
Nutrient Solution Concentration Affects Growth, Mineral Composition, Phenolic Acids, and Flavonoids in Leaves of Artichoke and Cardoon
Authors: Rouphael Youssef , Cardarelli Mariateresa , Lucini Luigi , Rea Elvira , Colla Giuseppe
Published: February 2019

A greenhouse experiment was conducted in Summer and Fall 2011 at the experimental farm of Tuscia University, central Italy, to study the effect of nutrient solution concentration (4, 20, 36, 52, or 68 mequiv·L−1) on biomass production, mineral composition, and concentrations of the major polyphenols in ‘Romolo’ artichoke and ‘Bianco Avorio’ cardoon grown in a floating system. Leaf dry biomass, leaf number, and macroelement concentrations (nitrogen, potassium, calcium, and magnesium) of artichoke and cardoon increased in response to an increase in the nutrient solution concentration, whereas an opposite trend was observed for the total polyphenols, phenolic acids (chlorogenic acid, cynarin, and caffeic acid), and the flavonoid luteolin. Artichoke and cardoon gave maximum biomass production and leaf number at 45 and 54 mequiv·L−1, respectively. Cardoon showed higher biomass and leaf number (average 1.13 kg·m−2 and 14.0 n./plant, respectively) than those observed in artichoke (average 1.07 kg·m−2 and 12.7 n./plant, respectively). The chlorogenic acid, cynarin, caffeic acid, and luteolin concentrations were higher by 204%, 462%, 580%, and 445% in cardoon leaf tissue than in that of artichoke. An improvement of leaf quality (total polyphenols, phenolic acids, and flavonoids) was obtained at the expense of leaf yield through the use of lower fertilizer concentrations in the nutrient solution.
Titers of ‘Ca. Liberibacter asiaticus’ in Murraya paniculata and Murraya-reared Diaphorina citri Are Much Lower than in Citrus and Citrus-reared Psyllids
Authors: Walter Abigail J. , Duan YongPing , Hall David G.
Published: February 2019

Huanglongbing, one of the most devastating diseases of citrus, is associated with the bacterium ‘Candidatus Liberibacter asiaticus’ vectored by the Asian citrus psyllid, Diaphorina citri, in North America. Murraya paniculata is a common ornamental plant that is an alternate host of both the psyllid and bacterium. We tested M. paniculata and Citrus sinensis grown together in the same field for their titer of ‘Ca. L. asiaticus’. We found the bacterium in both M. paniculata and C. sinensis, but the titer was four orders of magnitude lower in M. paniculata. We also assayed D. citri from laboratory colonies reared on either ‘Ca. L. asiaticus’-infected M. paniculata or infected Citrus spp. Psyllids reared on infected M. paniculata also carried bacterial titers five orders of magnitude lower than psyllids reared on infected Citrus spp. These observations imply resistance to huanglongbing in M. paniculata.
Hot Water Treatment Maintains Normal Ripening and Cell Wall Metabolism in Mango (Mangifera indica L.) Fruit
Authors: Zhang Zhengke , Gao Zhaoyin , Li Min , Hu Meijiao , Gao Hui , Yang Dongping , Yang Bo
Published: February 2019

‘Tainong 1’ mango fruit were treated with hot water for 10 minutes at 55 °C and then stored at 5 °C for 3 weeks. After removal from low-temperature storage, the effects of hot water treatment (HWT) on chilling injury (CI), ripening and cell wall metabolism during storage (20 °C, 5 days) were investigated. HWT reduced the CI development of the fruit as manifested by firmer texture, external browning, and fungal lesions. A more rapid ripening process, as indicated by changes in firmness, respiration rate, and ethylene production, occurred in heated fruit after exposure to low temperature as compared with non-heated fruit. At the same time, the cell wall components in heated fruit contained more water-soluble pectin and less 1,2-cyclohexylenedinitrilotetraactic acid (CDTA)-soluble pectin than those in non-heated fruit. HWT also maintained higher polygalacturonase [enzyme classification (EC) 3.2.1.15] and β-galactosidase (EC 3.2.1.23) activities as well as lower pectin methylesterase (EC 3.1.1.11) activity. In general, the changes of ripening and cell wall metabolism parameters in the heated fruit after low-temperature storage exhibited a comparable pattern to that of non-cold-stored fruit.
Effects of Different Application Methods of Controlled-release Fertilizers on Capillary Wick Culture of Tomato
Authors: Kinoshita Takafumi , Masuda Masaharu
Published: February 2019

Application of controlled-release fertilizer (CRF) to root-proof capillary-wick irrigation systems (a type of subirrigation method) has both economic and environmental benefits because it does not require any equipment for fertigation and minimizes water leaching. In this study, we compared three CRF fertilization methods: 1) mixed with the substrate completely [“mixed-fertilization” (MF)]; 2) packed in bags and placed on the wick [“packed bag-fertilization” (PF)]; and 3) supplied in the water reserve tank [“tank-fertilization” (TF)] in tomato cultivation using the root-proof capillary-wick irrigation system. We also refined the TF method to simplify and reduce labor requirements for fertilization of CRF and reuse of substrate. Fruit yield was lower in PF and TF than in MF because of high incidence of blossom-end rot (BER) in PF and TF during both cultivation periods, spring−summer and fall−winter. However, promotion of nitrification in TF by supplying nitrogen through the addition of bark compost and aeration of the water reserve tank increased fruit yield to the same level as that observed in MF as a result of a decrease in BER incidence. Nutrient residue in the substrate was lower in TF than in MF. On the basis of the analysis of nitrogen concentration in xylem exudates, the uptake ratio of NH4-N/NO3-N was thought to be lower in MF than in PF and TF. The high NH4-N uptake in PF and TF could be the cause of calcium (Ca) deficiency and increased incidence of BER. Thus, the use of “tank fertilization” of CRF in the root-proof capillary-wick irrigation system for tomato production is possible by promoting nitrification in the water reserve tank.
Application Timing of Aminocyclopyrachlor, Fluroxypyr, and Triclopyr Influences Swinecress Control in Tall Fescue
Authors: Reed Thomas V. , McCullough Patrick E.
Published: February 2019

Swinecress [Coronopus didymus (L.) Sm.] is a problematic weed in newly seeded tall fescue (Festuca arundinacea Schreb.) and often warrants control with herbicides. The objective of this research was to investigate the influence of application timing on efficacy of aminocyclopyrachlor, fluroxypyr, and triclopyr for swinecress control compared with dichlorophenoxyacetic acid (2,4-D) + 3,6-dichloro-o-anisic acid (dicamba) + methylchlorophenoxypropionic acid (MCPP). Aminocyclopyrachlor at 0.05 and 0.10 kg a.i./ha provided less than 35% control from February applications, but both rates averaged greater than 90% control with April applications. Fluroxypyr at 0.26 and 0.52 kg a.i./ha provided poor (less than 70%) control from February applications but control increased to 71% and 90% from April treatments, respectively. Triclopyr at 0.56 and 1.12 kg a.i./ha provided greater than 90% swinecress control at both application timings and was comparable to 2,4-D + dicamba + MCPP. Overall, aminocyclopyrachlor and fluroxypyr were only effective for controlling swinecress in April, whereas triclopyr provided excellent control with February and April applications.
Incidence of Misshapen Fruits in Strawberry Plants Grown under Tunnels Is Affected by Cultivar, Planting Date, Pollination, and Low Temperatures
Authors: Ariza María Teresa , Soria Carmen , Medina-Mínguez Juan Jesús , Martínez-Ferri Elsa
Published: February 2019

Misshapen fruit represent a significant problem for strawberry (Fragaria ×ananassa Duch.) producers around the world. We investigated the effect of cultivar and different cropping practices on the productivity of strawberry plants growing in tunnels at Huelva (Spain) over three years. In the first experiment, ‘Camarosa’, ‘Ventana’, and ‘Medina’ were planted on 10 or 22 Oct. at standard (30 × 25 cm), wide (35 × 25 cm), or narrow (25 × 25 cm) spacings. In the second experiment, ‘Camarosa’ was grown in macro- or microtunnels with and without bees. There was no effect of plant density. Planting time resulted in higher early yields in ‘Ventana’ and higher misshapen fruit in ‘Camarosa’ with an early compared with a late planting. ‘Camarosa’ had the lowest yields and the highest incidence of misshapen fruit. More of the early crop was misshaped and this was related to low temperatures in the 7 weeks before harvest. Pollination reduced the incidence of misshapen fruit and increased yield. Plants grown in macrotunnels were only more productive than those grown in microtunnels when they were pollinated by bees. These results demonstrate that the productivity of strawberry plants growing in tunnels can be enhanced by the selection of the appropriate cultivar, planting date, tunnel system, and pollination protocol. The use of macrotunnels with supplementary pollination results in better economic returns by increasing yield and decreasing the incidence of misshapen fruit. In addition, in some cultivars this profit can be enhanced by early planting, which enables early arrival of fruits into the markets at better prices for growers.