bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement of Salt Tolerance in Kentucky Bluegrass by Trinexapac-ethyl
Authors: Arghavani Masoud , Kafi Mohsen , Babalar Mesbah , Naderi Roohangiz , Hoque Md. Anamul , Murata Yoshiyoki
Published: February 2019

Trinexapac-ethyl (TE) is a popular plant growth regulator in the turfgrass industry that inhibits gibberellic acid (GA) biosynthesis and effectively reduces leaf elongation and subsequent clipping production. This greenhouse sand culture experiment was conducted to determine effects of TE application on kentucky bluegrass (Poa pratensis L.) responses to salinity stress. The five salinity levels (0, 20, 40, 60, and 80 mm NaCl) were applied in nutrient solutions and TE treatments (0, 1, and 1.7 g/100 m2) were applied twice at 4-week intervals. Under non-saline conditions and low level salinity conditions, application of TE at 1 g/100 m2 (TE1) increased turf quality (TQ), leaf total non-structural carbohydrates (TNC), and chlorophyll (Chl) content. In high salinity, TE1 alleviated the decline in TQ, antioxidant enzyme activities, leaf TNC, Chl, and K+ content. In addition, treated turf with TE at 1 g/100 m2 had lower proline, Na+, and malondialdehyde (MDA) contents. However, the adverse effects of high salinities were more pronounced when turf was treated by TE at 1.7 g/100 m2 (TE1.7), suggesting that effects of TE on salt tolerance vary with its dosages and salinity levels. We concluded that moderate inhibition of GA biosynthesis by TE enhances salt tolerance in kentucky bluegrass and suggest that enhancement is the result of the maintenance of antioxidant activities, leading to more root growth and greater levels of TNC and Chl content. Chemical names used: 4-(cyclopropyl-β-hydroxymethylene)-3, 5-dioxocyclohexanecarboxylic acid ethyl ester (trinexapac-ethyl).
Genetic Methods for Mitigating Invasiveness of Woody Ornamental Plants: Research Needs and Opportunities
Authors: Vining Kelly J. , Contreras Ryan N. , Ranik Martin , Strauss Steven H.
Published: February 2019

Because cultivation of exotic woody ornamental plants has led to establishment of a number of invasive species, there is considerable interest in breeding methods to reduce the propensity for spread. We review progress in conventional breeding and transgenic biotechnology approaches to producing sterile forms of ornamental woody plants. Conventional forms of inducing sterility, including induction of polyploidy, interspecific hybridization, and mutagenesis, are generally inexpensive and can be applied to a diversity of species at low to moderate cost. They have also been shown to be capable of producing commercially successful cultivars. In contrast, despite a variety of highly promising and rapidly developing approaches using transgenic methods, the inability to efficiently regenerate and genetically transform most ornamental species makes application of these innovations highly problematic. Moreover, because of the fragmented pattern of ornamental nursery ownership, the numerous species and varieties used, and the high regulatory cost for permits to sell most types of transgenic varieties (even when their environmental risk of spread has been reduced by sterility), application of transgenic methods is largely infeasible. A combination of fundamental regulatory reform and expanded biological research on generalized transformation and sterility methods is needed to overcome these barriers.
Broad-sense Heritability Estimates of Turfgrass Performance Characteristics in Native Prairie Junegrass Germplasm
Authors: Clark Matthew D. , Watkins Eric
Published: February 2019

Prairie junegrass [Koeleria macrantha (Ledeb.) Shultes] is a perennial, short-grass prairie species distributed throughout the Northern Hemisphere that is being evaluated for use as a low-input turf. In June 2007, 300 genotypes representing collection locations derived from Colorado, Nebraska, and Minnesota germplasm were grown and evaluated 3 years for turfgrass performance characteristics in a randomized complete block design with five clonal replications at two locations (St. Paul, MN, and Becker, MN). After establishment, plots received no supplemental irrigation or fertility and were mowed weekly to a height of 6.4 cm. Broad-sense heritability estimates were calculated on a clonal mean (Hc) and single-plant (Hsp) basis for turf quality (Hc = 0.62, Hsp = 0.13), crown density (Hc = 0.55, Hsp = 0.09), mowing quality (Hc = 0.59, Hsp = 0.09), and genetic color (Hc = 0.45, Hsp = 0.06). The heritability estimates indicate that selection for these traits should result in significant gains in germplasm improvement. Differences were observed in the means and variances among clones, collection locations, and/or collection regions for many of the traits evaluated including rust severity (Puccinia spp.), spring green-up, plant height, lateral spread, vertical regrowth, and flowering traits. The positive correlations among some of these traits and those with moderate heritability estimates should allow for multi-trait selection in cultivar development.
Predicting Flower Phenology and Viability of Highbush Blueberry
Authors: Kirk Anna K. , Isaacs Rufus
Published: February 2019

To maximize yield of pollination-dependent agricultural crops, farmers must ensure that sufficient pollinators are present when flowers are open and viable. We characterized and compared the lower development threshold temperature, bloom phenology, and flower viability of five common cultivars of highbush blueberry (Vaccinium corymbosum L.) to enable prediction of when flowers would be available for pollination. Threshold temperatures of all cultivars were found to be very similar and range between 7 and 8 °C. Logistic regression was used to characterize bloom phenology for all cultivars under field and greenhouse conditions. Bloom phenology under greenhouse conditions was delayed ≈100 growing degree-days when compared with field conditions. Average flower viability was determined daily from first flower opening until 5 days after flower opening for each cultivar. Results indicated declining flower viability with increasing flower age with most flowers unsuitable for pollination more than 4 days after opening. Implications of these results for planning pollination of highbush blueberry fields are discussed.
Vermicompost Leachate Alleviates Deficiency of Phosphorus and Potassium in Tomato Seedlings
Authors: Arthur Georgina D. , Aremu Adeyemi O. , Kulkarni Manoj G. , Van Staden Johannes
Published: February 2019

As a result of the growing concerns about the adverse effect of chemicals on the environment, agricultural practices involving organic and environmental-friendly compounds are gaining acceptance globally. Tomatoes remain one of the most popular and widely grown vegetable crops. However, their growth requires a high supplement of nitrogen–phosphorus–potassium (NPK) fertilizer. The effectiveness of vermicompost leachate (VCL) as a potential replacement for the three elements (N, P, and K) during the growth of greenhouse tomatoes was evaluated. Morphological appearance of the tomato seedlings was remarkably enhanced when Hoagland’s nutrient solution (50%) was supplemented with VCL (1:10 v/v). In the absence of both P and K, the addition of VCL significantly (P = 0.05) increased various growth parameters such as shoot length, leaf number as well as shoot and root fresh weight compared with the control tomato seedlings. The detrimental effect of N deficiency on the growth of tomato seedlings was not alleviated with the addition of VCL to the nutrient solution. The photosynthetic pigment content in P-deficient and VCL-supplemented tomato seedlings was significantly higher than the untreated control. The presence of VCL alleviated the detrimental effects caused by deficiency of P and K during the growth of the tomato seedlings. Overall, the use of VCL was beneficial with either complete nutrient solution or in the absence of P and K. Findings of this study suggest that VCL could serve as a potential substitute for P and K deficiency.
Taro (Colocasia esculenta) Transformed with a Wheat Oxalate Oxidase Gene for Improved Resistance to Taro Pathogen Phytophthora colocasiae
Authors: He Xiaoling , Miyasaka Susan C. , Fitch Maureen M.M. , Khuri Sawsan , Zhu Yun J.
Published: February 2019

Production of taro [Colocasia esculenta (L.) Schott], a tropical root crop, is declining in many areas of the world as a result of the spread of diseases such as Taro leaf blight (TLB). Taro cv. Bun Long was transformed through Agrobacterium tumefaciens with the oxalate oxidase (OxO) gene gf2.8 from wheat (Triticum aestivum). Insertion of this gene was confirmed by polymerase chain reaction (PCR) and Southern blot analysis. One independent transformed line contained one gene insertion (g5), whereas a second independent line contained four copies of the gene. Reverse transcriptase PCR (RT-PCR) confirmed the expression of this gene in line g5. Histochemical analysis of the enzyme oxalate oxidase confirmed its activity increased in the leaves of line g5. A bioassay for resistance to TLB used zoospores of Phytophthora colocasiae to inoculate tissue-cultured plantlets. Transgenic line g5 showed the complete arrest of this disease; in contrast, the pathogen killed non-transformed plants by 12 days after inoculation. A second bioassay, in which spores of P. colocasiae were inoculated onto disks of leaves of one-year-old potted plants, confirmed that transgenic line g5 had greatly increased resistance to this pathogen. This is the first report to demonstrate that genetic transformation of a crop species with an OxO gene could confer increased resistance to a pathogen (P. colocasiae) that does not secrete oxalic acid (OA).
Pungency of Red Radish Storage Roots Is Unaffected by Spent Mushroom Substrate or Yard Waste Compost Treatments Used for Field Production
Authors: Kahn Brian A. , Maness Niels O. , Chrz Donna R. , Carrier Lynda K.
Published: February 2019

Field experiments were conducted at Bixby, OK, in 2007. Four compost treatments and an unamended control were compared for field production of eight (spring) or four (fall) red radish (Raphanus sativus L.) cultivars. Treatments were either spent mushroom substrate or yard waste compost spread over plots to an average depth of 2.5 or 5 cm and preplant-incorporated ≈5 to 7 cm deep. Radishes were direct-seeded into prepared plots and subsequently grown using standard cultural practices. Samples of median-sized marketable storage roots were shredded and juice was analyzed in the laboratory for pungency as measured by isothiocyanate (ITC) concentration (primarily 4-methylthio-3-butenyl isothiocyanate). In the spring, mean ITC concentrations ranged from 28.2 to 36.8 μmol per 100 g juice in storage roots from the four compost treatments, and differences were not significant (α = 0.05). There were not enough storage roots to analyze from the unamended control plots as a result of herbicide toxicity. Cultivars differed in mean concentration of ITCs, ranging from a high of 52.9 μmol per 100 g juice for ‘Cherry Belle’ to a low of 19.2 μmol per 100 g juice for ‘Crunchy Royale’. In the fall, mean ITC concentrations ranged from 10.5 to 24.6 μmol per 100 g juice in storage roots from the four compost treatments. Differences were not significant (α = 0.05), and there were no differences from the control value of 17.5 μmol per 100 g juice. The mean ITC concentration was 19.9 μmol per 100 g juice for the four cultivars tested in the fall, and the cultivars did not differ. Results indicate that the tested compost treatments did not affect pungency of red radish storage roots as measured by concentrations of ITCs.
Studies on the Propagation of Jamaican Ackee (Blighia sapida L.) by Air-layering
Authors: Maurya Rajendra P. , Lewis Dion M. , Chandler Jeff St. A.
Published: February 2019

This study was conducted to determine the effects of indole-3-butyric acid (IBA) on the air-layering propagation of Jamaican ackee (Blighia sapida L.). Blighia sapida L. is a woody perennial, evergreen multipurpose fruit tree species native to the Guinean forests of West Africa. The fleshy arils of the ripened fruits are edible. All selected mother plants were fully grown mature, vigorous, healthy, and disease-free trees located within the landscape at The University of the West Indies, Cave Hill Campus. The experiment was laid out as a randomized block design with five different concentrations of the rooting hormone (0, 2000, 2500, 3000, and 3500 ppm) IBA and individual trees as blocks. The highest (100%) rooting success, maximum (108.0) number of roots, longest (16.0 cm) root length, and maximum (11.9 g) fresh weight and (3.7 g) dry weight of roots per stem were recorded in the treatment of 3500 ppm IBA. The results of this study can benefit fruits and nursery growers interested in propagating true-to-type Blighia sapida plants.
Above- and Belowground Microclimate of Grow Tubes in an Organic Mulch-incorporated, Raised Bed System for Blueberry
Authors: Tarara Julie M. , Chaves Bernardo , Strik Bernadine C.
Published: February 2019

Grow tubes are well established in forestry and are gaining attention in establishing some woody perennial crops. To date, microclimate descriptions have addressed the aboveground environment, but a mulched raised bed system with organic mulch-incorporated soil requires both the above- and belowground microclimate to be quantified. We measured the microclimate of commercially used, non-ventilated translucent and non-ventilated opaque grow tubes in a model crop of blueberry (Vaccinium corymbosum L.) grown on sawdust-mulch-covered raised beds formed from sawdust-incorporated tilled soil. The differences in air temperature between tubes and ambient were consistent with those reported in the literature. Air temperature in translucent tubes was up to 19.7 °C higher than ambient. Differences in vapor pressure deficit were largely a function of differences in air temperature between tubes and ambient rather than actual vapor pressure. Stem temperatures were highest outside of the tubes as a result of radiation load. The surface temperature of ambient sawdust mulch (maximum 53 °C) was up to 14 °C above that in the translucent tube and 20 °C above that in the opaque tube. The largest gradients in the bed system were between the loose dry mulch and the soil–mulch interface. The presence of a grow tube did not influence soil temperature or its daily amplitude at 15 cm below the surface—the native tilled soil. Temperatures associated with the opaque tubes were between ambient and those in the translucent tubes. The temperature data indicate that both opaque and translucent unventilated grow tubes should influence shoot and crown growth but may have little influence on root growth in this shallow-rooted plant.
Nutrient Density in Lettuce Cultivars Grown with Organic or Conventional Fertilization with Elevated Calcium Concentrations
Authors: Meagy Md J. , Eaton Touria E. , Barker Allen V.
Published: February 2019

Calcium-rich vegetables in the diet could ameliorate the potential for calcium (Ca) deficiency in human nutrition. This study investigated the prospect of increasing Ca density of lettuce (Lactuca sativa L.) through cultivar selection and nutrient management in a greenhouse. Eighteen lettuce cultivars including butterhead, romaine, and loose-leaf phenotypes of heritage and modern genetics were tested. Organic fertilizer (3N–0.7P–3.3K) and commercial conventional fertilizer (20N–4.4P–16.6K) factored with three Ca levels (50, 100, 200 mg·L−1 as CaCl2) were the fertilizer regimes. Calcium in whole shoots was analyzed by atomic absorption spectrometry of oven-ashed samples. Heritage cultivars had a significantly higher Ca concentration (1.93% dry weight) than modern cultivars (1.54%). Loose-leaf phenotypes had the highest Ca concentration (2.06%) followed by butterhead (1.66%) and romaine (1.49%). Accumulation of Ca was higher with the conventional fertilizer (1.90%) than with the organic fertilizer (1.58%). Elevated Ca level in the fertility regimes raised the Ca concentration in lettuce from 1.56% at 50 mg·L–1 to a mean of 1.82% at 100 mg·L−1 and 200 mg·L−1. Large differences in Ca concentration occurred among individual cultivars with ranges from 1.27% to 3.05%. ‘Salad Bowl’, ‘Red Deer Tongue’, ‘Buttercrunch’, and ‘Bronze Mignonette’ were the top in cultivar ranking with mean Ca concentration of 2.50%, whereas ‘Adriana’, ‘Australe’, ‘Coastal Star’, and ‘Forellenschluss’ were low accumulators with a mean of 1.33%. Head size of cultivars had no correlation with Ca concentration. This experiment indicates that selection of nutrient regimes and cultivars can be used to increase Ca accumulation in lettuce.
Thermography Study of Moderate Electrical Conductivity and Nutrient Solution Distribution System Effects on Grafted Tomato Soilless Culture
Authors: Morales Isidro , Urrestarazu Miguel
Published: February 2019

In recent decades, salinity in the culture of tomatoes has been one of the most studied parameters. This study aimed to evaluate the effect of a moderate increase in salinity, fertigation distribution, and its control using thermography on a soilless culture of grafted tomato. A tomato crop (cv. Ramyle) grafted onto tomato rootstocks (cv. Emperor) was cultivated in coir crop units at the University of Almeria from Nov. 2012 to May 2013. A plot design subdivided with four blocks was used, with salinity values of 2.0 and 2.5 dS·m−1 in the main plots and fertigation distribution systems with either one (DD1) or four (DD4) drip manifolds in the subplots. The crop productivity was measured using total crop yield, commercial value, and size. The quality parameters in the fruits were not significantly affected. Thermographies were used to aid the control of differential transpiration exerted by salinity. The difference in salinity did not significantly affect the total or commercial production. However, despite being grafted plants, there was a statistically significant effect (P ≤ 0.05) on the fruit size distribution when the electrical conductivity (EC) of the nutrient solution was increased from 2.0 to 2.5 dS·m−1, with a lower production (16%) of large fruits and an increased production of smaller fruits. The DD4 system significantly increased large tomato production (22%) compared with DD1, and the quality parameters in the fruits were not significantly affected. As a result of the improvement in tomato size, the DD4 distribution system economically offset the required higher initial expenditure compared with the DD1 system. Thermography was revealed to be a robust, simple, and quick tool for diagnosing the effect of salinity on transpiration.
Nutritive Constituents of Onion Grown from Sets as Affected by Water Supply
Authors: Ombódi Attila , Koczka Noémi , Lugasi Andrea , Daood Hussein Gehad , Berki Mária , Helyes Lajos
Published: February 2019

A 3-year experiment was conducted in central Hungary comparing the effect of an irrigation treatment on content and yield of dry matter, storage carbohydrates, vitamin C, total flavonols, and total polyphenols of onion (Allium cepa L.) grown from sets. Rain-fed plots were set as controls. Conditions during the first 40 days of the growing season had a decisive effect on yield and bulb size; warmer and dryer weather during this period resulted in lower yield. Colder and wetter weather conditions resulted in higher bulb yield, but also decreased accumulation of secondary metabolites. Dry matter content values ranged between 12% and 14% and were not influenced by the water supply. Storage carbohydrate-to-dry matter ratio was not changed by the water supply. Total flavonol contents (sum of the concentrations of nine individual flavonols) varied between 430 and 753 mg·kg−1 on a fresh weight basis. Total polyphenol values ranged between 607 and 1029 mg·kg−1 on a fresh weight basis. A statistically significant correlation was found between flavonol content and polyphenol content for the rain-fed treatment, but this was not the case for the irrigation treatment. Irrigation significantly increased total flavonol and total polyphenol concentrations during the dry years. Irrigation significantly increased the bulb yield by 33% to 160%, depending on the year. Consequently, by applying irrigation, yields of nutritive compounds became 1.5 to two times higher.
Host Resistance to Pear Psylla of Breeding Program Selections and Cultivars
Authors: Bell Richard L.
Published: February 2019

Twenty-one pear cultivars and breeders’ selections with interspecific pedigrees involving Pyrus ussuriensis Max. or P. pyrifolia (Burm.) Nakai crossed with P. communis were assessed for resistance to pear psylla (Cacopsylla pyricola Förster) using a nymphal feeding antixenosis assay. The proportion of nymphs live and present on the plants varied from 0.52 for Purdue 77-73, a P. ussuriensis × P. communis hybrid, to 0.08 for ‘Zelinka’, a P. communis cultivar from eastern Europe. Two P. ussuriensis × P. communis hybrid selections (NY 10355 and NY 10359) and the P. communis landrace cultivars, Batjarka and Zelinka, were the most resistant to nymphal feeding. NJ B9 T1 T117 may also be a useful source of resistance. The most resistant germplasm should be valuable genetic resources for the breeding of new pear cultivars with resistance to pear psylla.
Integrating Field and GIS-based Surveys to Map the Distribution and Characterize the Ecological Habitat for Conservation Management of Georgia Plume, a Rare Endemic
Authors: Porter Justin A. , Berle David , Wetzstein Hazel Y.
Published: February 2019

Accurate mapping, inventory assessment, and habitat descriptions are critically important for the development of plant conservation strategies of rare plants. Georgia plume, Elliottia racemosa (Ericaceae), is a rare threatened plant endemic only to the state of Georgia. In this study, census and distribution data were collected and the ecological habitat characterized for all known populations of georgia plume using geographic information system/global positioning system (GIS/GPS)-based methods. Causes for population losses and decline were assessed by evaluating both extant populations and historically reported but currently inactive sites. Landowner permission was obtained to visit 56% (32 of 57) of all known recorded populations. Over 40% of visited locations no longer contained georgia plume; 58% of inactive sites were associated with anthropogenic disturbances including farming and timber. Populations not visited by ground were evaluated using aerial photographs: of 29 putative populations, 66% were judged highly unlikely to contain georgia plume based on current land use. Census data verified that many populations have few individuals: 75% contained less than 45 individuals; over one-third contained 12 or fewer individuals. Over 80% of extant populations had an area of less than 0.3 ha. Field and aerial assessments of recent and historically noted populations confirm that georgia plume has disappeared from many previously reported locations and that fewer than two dozen populations may remain.
Bell Pepper (Capsicum annum L.) Crop as Affected by Shade Level: Microenvironment, Plant Growth, Leaf Gas Exchange, and Leaf Mineral Nutrient Concentration
Authors: Díaz-Pérez Juan Carlos
Published: February 2019

Use of shading nets helps ameliorate heat stress of vegetable crops. This study evaluated the effects of shade level on microenvironment, plant growth, leaf gas exchange, and mineral nutrient content of field-grown bell pepper crop. Bell pepper cultivars Camelot, Lafayette, Sirius, and Stiletto were grown at 0%, 30%, 47%, 62%, and 80% shade levels. Photosynthetically active radiation and air, leaf, and root zone temperatures decreased as shade level increased. Despite having increased plant leaf area, there was increased soil water content with increased shade level, indicating reduced soil water use. With increased shade level, the total plant leaf area, individual leaf area, and individual leaf weight increased, whereas leaf number per plant and specific leaf weight decreased. In contrast to non-normalized chlorophyll index (CI) values, CI normalized by specific leaf weight were related to leaf nitrogen (N) and increased with increased shade level. Net photosynthesis and stomatal conductance (gS) decreased and leaf transpiration increased with increased shade level, particularly above 47% shade level. Leaf concentrations of N, potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), sulfur (S), aluminum (Al), and boron (B) increased with increased shade level. Relatively few differences in plant growth, leaf gas exchange, and leaf mineral nutrient concentrations were observed among cultivars. In conclusion, morphological changes such as taller plants and thinner and larger leaves likely enhanced light capture under shaded conditions compared with unshaded plants. High shade levels reduced leaf temperature and excessive leaf transpiration but resulted in reduced leaf photosynthesis. Thus, moderate shade levels (30% and 47%) were the most favorable for bell pepper plant growth and function.
Influence of Phostrade Ca on Color Development and Anthocyanin Content of ‘Braeburn’ Apple (Malus domestica Borkh.)
Authors: Bizjak Jan , Weber Nika , Mikulic-Petkovsek Maja , Slatnar Ana , Stampar Franci , Alam Zobayer , Stich Karl , Halbwirth Heidi , Veberic Robert
Published: February 2019

The influence of two foliar applications of Phostrade Ca, which contains high concentrations of phosphorus and minor amounts of calcium and nitrogen, on color development and selected primary and secondary metabolites was investigated during advanced maturation of ‘Braeburn’ apple. Changes of hydroxycinnamic acids, flavanols, dihydrochalcones, flavonols, and anthocyanins were monitored six times during the advanced ripening until technological maturity of the fruits. Additionally, the changes in the chromatic values a*, h°, and the lightness coefficient L* were recorded weekly. The colorimetric parameters showed a significant difference in the intensity of red coloration between the treated and untreated apples. Spraying with Phostrade Ca also resulted in a significant increase in most individual sugars, total sugars, and concentration of anthocyanins and flavonols. Moreover, the amount of phosphorus (P) in the treated leaves was increased. However, the total phenolic content and accumulation of other classes of flavonoids such as hydroxycinnamic acids, flavonols, and dihydrochalcones were not influenced. Phostrade Ca treatment significantly increased dihydroflavonol 4-reductase (DFR) and slightly flavanone-3-hydroxylase (FHT) activity, which were correlated with anthocyanin synthesis but had no effect on phenylalanine ammonia lyase (PAL) and chalcone synthase/chalcone isomerase (CHS/CHI) activity. The results indicate that two foliar applications of Phostrade Ca late in the growing season represent an effective way to improve the color of ‘Braeburn’ apples at commercial harvest.
Smartphone Use and Online Search and Purchase Behavior of North Americans: Gardening and Non-gardening Information and Products
Authors: Behe Bridget K. , Campbell Benjamin L. , Hall Charles R. , Khachatryan Hayk , Dennis Jennifer H. , Yue Chengyan
Published: February 2019

Information plays a vital role in the purchase decisions of retail lawn and garden consumers. Consumers have readily adopted personal computers and Internet technology as a way of seeking information and/or making purchases online. However, the extent to which horticultural consumers specifically seek information and make purchases online is not well documented. Our interests for this project were driven by an interest in the impact of smartphone ownership and Internet search behavior on product purchasing related to gardening products and items and how search and purchase were similar to (or different from) non-gardening information and products. Given the sharp rise in the use of smartphones and mobile media use, we explored differences among online shoppers, specifically those who had searched online for gardening information with those who were online for other purposes. We found differences between those who had searched online for non-gardening information compared with those who had searched online for gardening information. Women were more likely to search online for both gardening and non-gardening information, but men were more likely to make online gardening purchases. Education level, ethnicity, and geographic location of residence had varying impacts on the likelihood of online search and purchase. Having searched online for non-gardening information increased the likelihood of an online purchase by 16%, whereas the likelihood of purchase increased to 19% for online gardening-related searches.
Effects of Duration and Temperature in Simulated Dark Shipping on the Subsequent Performance of the Nobile-type Dendrobiums
Authors: Cinantya Ariningsun P. , Chen Fure-Chyi , Alex Chang Yao-Chien
Published: February 2019

The popularity of the nobile-type dendrobium (Dendrobium nobile hybrids) has been increasing globally. More information regarding the effects of long-distance shipping, from producing countries to destination market countries, on the post-shipping plant performance is needed. In this study, two nobile-type dendrobium cultivars were subjected to simulated dark shipping (SDS) at various temperatures and durations. Changes in net CO2 uptake rate (Pn), chlorophyll fluorescence, and leaf relative water content after plants had been treated with SDS were investigated. Furthermore, shipped plants were vernalized to investigate the effect of dark shipping on the subsequent flowering quality. Dark shipping for 7 days at 15 °C did not affect the post-shipping photosynthetic performance of D. Lan Tarn Beauty. Increasing the shipping duration from 7 to 21 days increased the time required for Pn recovery from 1 to 12 days. Dendrobium Lan Tarn Beauty recovered its Pn within 4 days when shipped for 21 days at 10 °C, and this was prolonged to 11 days when the plants were shipped at 20 °C. Changes in Fv/Fm indicated that there was no marked damage to either cultivars, and the leaf relative water content was little affected by SDS. Dendrobium Lan Tarn Beauty and D. Lucky Girl shipped at 10 °C flowered 5 and 8 days earlier, respectively, compared with unshipped plants. Regardless of the shipping conditions, shipped D. Lucky Girl had a lower flower diameter and higher total flower count than unshipped plants. No differences were found in the number of nodes with flowers or the total flower count between shipped and unshipped D. Lan Tarn Beauty. Our study suggested that dark shipping for up to 21 days is possible for nobile-type dendrobiums. We recommend shipping temperatures of 10 to 15 °C to reduce the detrimental effects caused by long-term dark shipping.
Seed Germination of Arbutus unedo, A. andrachne and Their Natural Hybrid A. andrachnoides in Relation to Temperature and Period of Storage
Authors: Bertsouklis Konstantinos F. , Papafotiou Maria
Published: February 2019

Arbutus unedo L., A. andrachne L., and their natural hybrid, A. ×andrachnoides Link, are the three Arbutus species of the Eastern Mediterranean Macchia. A. unedo is used as an ornamental plant and as cut foliage, whereas the other two species have the potential to be introduced to the floricultural industry. This study was carried out to clarify whether the seeds of these Arbutus species possess dormancy to determine the temperature range for their germination and the effects of storage period on germination. Seeds of the three species, which were stored dry at 25 °C for either three or 11 months, germinated at very high percentages (82% to 99%) and in a short period of time (24 to 46 days) when incubated at 15 or 10 °C without any pretreatment proving that they do not possess dormancy; germination was faster at 15 °C. At 20 °C only seeds of A. unedo and A. andrachne stored for three months germinated (29% to 34%), whereas at 25 °C, there was practically no germination. Seeds stored for three months germinated (61% to 75%) when incubated at 5 °C, but the germination was delayed and the seedlings did not grow further than the appearance of the radicle unless transferred at a higher temperature (10 to 25 °C). After 27 months of dry storage at 25 °C, seeds did not germinate when incubated at the range of 10 to 25 °C even after pretreatment with cold stratification.
Nitrate-Nitrogen Sufficiency Ranges in Leaf Petiole Sap of Brassica oleracea L., Pac Choi Grown with Organic and Conventional Fertilizers
Authors: Altamimi May Elfar , Janke Rhonda R. , Williams Kimberly A. , Nelson Nathan O. , Murray Leigh W.
Published: February 2019

Greenhouse experiments were conducted to determine the response of Brassica oleracea L., pac choi to fertilizer rates and sources and to establish optimal soluble nitrogen (N) application rates and nitrate meter sufficiency ranges. Conventional soluble fertilizer was formulated from inorganic salts with a 4:1 NO3-N:NH4-N ratio. Phosphorus (P) was held at 1.72 mm and potassium (K) at 0.83 mm for all treatment levels. The organic soluble fertilizer, fish hydrolyzate (2N–1.72P–0.83K), was diluted to provide the same N levels as with conventional treatments. Both fertilizers were applied at N rates of 0, 32, 75, 150, 225, 300, and 450 mg·L−1. Seedlings were transplanted and fertilizer application began at 18 days. Plants were harvested at 7 weeks (5 weeks post-transplanting) after receiving 15 fertilizer applications during production. Samples of the most recently matured leaves were harvested weekly and analyzed for petiole sap NO3-N and leaf blade total N concentration. Leaf count, leaf length, and chlorophyll content were also measured weekly. Fresh and dry weights were determined on whole shoots and roots. Optimum yield was achieved at the 150-mg·L−1 fertility rate with both conventional and organic fertilizers. Field and high tunnel experiments were conducted to validate the sufficiency ranges obtained from the greenhouse studies. Sufficiency levels of NO3-N for pac choi petiole sap during Weeks 2 to 3 of production were 800 to 1500 mg·L−1 and then dropped to 600 to 1000 mg·L−1 during Weeks 4 through harvest for both conventional and organic fertilizers sources. Total N in leaf tissue was less responsive to fertilizer rate effects than petiole sap NO3-N. Chlorophyll content was not useful in evaluating pac choi N status. These guidelines will provide farmers with information for leaf petiole sap NO3-N to guide in-season N applications.
Uptake of Mn and Zn by Cucumber Grown in Closed Hydroponic Systems as Influenced by the Mn and Zn Concentrations in the Supplied Nutrient Solution
Authors: Tzerakis Constantinos , Savvas Dimitrios , Sigrimis Nick , Mavrogiannopoulos Georgios
Published: February 2019

The objective of the present experiment was to estimate the uptake of manganese (Mn) and zinc (Zn) by cucumber in closed hydroponic systems at different Mn and Zn concentrations in the recycled nutrient solution under Mediterranean climatic conditions. The obtained data might be used to manage Mn and Zn supply in closed hydroponic crops of cucumber grown in Mediterranean greenhouses and avoid their accumulation to toxic levels. Four Mn levels (10, 40, 80, 120 μM) at a standard Zn concentration (6 μM) and four Zn levels (6, 20, 40, 60 μM) at a standard Mn concentration (10 μM) in the solution supplied to compensate for nutrient and water uptake by plants were applied as experimental treatments. The actual uptake concentrations of Mn and Zn were estimated by applying two different methods. The first method was based on the removal of Mn, Zn, and water from the recycling nutrient solution, whereas the second method was based on the total quantities of Mn and Zn that were recovered in plant biomass in combination with the total water uptake. Both methods gave similar uptake concentrations for Mn in the low-Mn supply level and Zn in all Zn levels. However, in the three higher Mn supply levels, the values estimated on the basis of nutrient removal from the recirculating nutrient solution were significantly higher than those found by measuring the total Mn content in plant biomass. These discrepancies in the three high-Mn treatments were possibly caused by partial immobilization of Mn by oxidizing bacteria in the nutrient solution.
Effectiveness of Squid Hydrolysate as a Home Lawn Fertilizer
Authors: Fetter Joseph C. , Brown Rebecca N. , Amador José A.
Published: February 2019

Consumer demand for cleaned squid generates a substantial amount of waste that must be properly disposed of, creating an economic burden on processors. A potential solution to this problem involves converting squid byproducts into an organic fertilizer, for which there is growing consumer demand. Organic fertilizers are reputed to offer advantages that synthetic fertilizers cannot provide, such as increasing soil water- and nutrient-holding capacity and promoting the growth of beneficial soil organisms. To evaluate the effectiveness of hydrolyzed squid waste as an organic fertilizer, we quantified soil fertility and turfgrass quality on perennial ryegrass turf (Lolium perenne L.) amended with two types of fertilizer: squid-based (SQ) or synthetic (SY). Field plots were established on an Enfield silt loam in Kingston, RI, and liquid (L) or granular (G) fertilizer formulations of squid or synthetic fertilizers were applied at 0, 48, 146, and 292 kg nitrogen/ha/year. Soil physical, chemical, and biological properties were determined monthly and turfgrass quality was determined periodically during the growing season in 2008 and 2009. Squid hydrolysate applied as a liquid (SQL) and granular (SQG) fertilizer consistently provided high-quality, uniform turf when compared with synthetic fertilizer applied at the same rate. Soil concentrations of NO3, NH4, PO4, pH, moisture, soil organic matter, C:N ratio, and levels of trace metals were unaffected by fertilizer type, formulation, or rate throughout the two-year study. Both squid-based organic fertilizer formulations gave significantly higher microbial activity rates than their synthetic counterparts regardless of application rate. Conversion of squid processing byproducts into fertilizer has the potential to improve turfgrass quality while providing a sustainable solution to waste disposal problems in the seafood processing industry.
Spectral Effects of Three Types of White Light-emitting Diodes on Plant Growth and Development: Absolute versus Relative Amounts of Blue Light
Authors: Cope Kevin R. , Bugbee Bruce
Published: February 2019

Light-emitting diodes (LEDs) are a rapidly developing technology for plant growth lighting and have become a powerful tool for understanding the spectral effects of light on plants. Several studies have shown that some blue light is necessary for normal growth and development, but the effects of blue light appear to be species-dependent and may interact with other wavelengths of light as well as photosynthetic photon flux (PPF). We report the photobiological effects of three types of white LEDs (warm, neutral, and cool, with 11%, 19%, and 28% blue light, respectively) on the growth and development of radish, soybean, and wheat. All species were grown at two PPFs (200 and 500 μmol·m−2·s−1) under each LED type, which facilitated testing the effect of absolute (μmol photons per m−2·s−1) and relative (percent of total PPF) blue light on plant development. Root and shoot environmental conditions other than light quality were uniformly maintained among six chambers (three lamp types × two PPFs). All LEDs had similar phytochrome photoequilibria and red:far red ratios. Blue light did not affect total dry weight (DW) in any species but significantly altered plant development. Overall, the low blue light from warm white LEDs increased stem elongation and leaf expansion, whereas the high blue light from cool white LEDs resulted in more compact plants. For radish and soybean, absolute blue light was a better predictor of stem elongation than relative blue light, but relative blue light better predicted leaf area. Absolute blue light better predicted the percent leaf DW in radish and soybean and percent tiller DW in wheat. The largest percentage differences among light sources occurred in low light (200 μmol·m−2·s−1). These results confirm and extend the results of other studies indicating that light quantity and quality interact to determine plant morphology. The optimal amount of blue light likely changes with plant age because plant communities balance the need for rapid leaf expansion, which is necessary to maximize radiation capture, with prevention of excessive stem elongation. A thorough understanding of this interaction is essential to the development of light sources for optimal plant growth and development.
Compost Teas and Reused Nutrient Solution Suppress Plant Pathogens In Vitro
Authors: Tian Xiuling , Zheng Youbin
Published: February 2019

In vitro testing was conducted to evaluate the inhibition potential of three compost teas (pine bark, manure, and vermicasting), Root Rescue Landscape Powder® (a mix of mycorrhizae and other beneficial microbes), waste diatomaceous earth (DE; from beer brewing), and a greenhouse nutrient solution, which had been reused for 20 years on six plant pathogens: Fusarium foetens, Rhizoctonia solani, Sclerotinia sclerotiorum, Phytophthora cryptogea, Pythium intermedium, and P. ultimum. The test materials showed in vitro inhibition on most of the test pathogens. Pine bark tea suppressed growth of all six pathogens, and inhibition exceeded 50% after 10 days of coincubation. Vermicasting tea showed over 40% inhibition against S. sclerotiorum and F. foetens; manure tea showed 42% inhibition against F. foetens; DE showed 40% inhibition against F. foetens, S. sclerotiorum, and R. solani; whereas reused greenhouse nutrient solution showed 56.7% inhibition against R. solani and 43.4% inhibition against F. foetens; Root Rescue showed 66% inhibition against P. intermedium. The results suggest that the six test materials have potential in the control of these soil- and water-borne pathogens in plant production system.
Genetic Diversity of Species of Chrysanthemum and Related Genera and Groundcover Cultivars Assessed by Amplified Fragment Length Polymorphic Markers
Authors: Chen Xuejuan , Sun Ming , Liang Jianguo , Xue Hui , Zhang Qixiang
Published: February 2019

Chrysanthemums have beautiful flowers with high ornamental value and rich genetic diversity. Amplified fragment length polymorphism (AFLP) markers were used to detect the relationships among 12 wild accessions and 62 groundcover chrysanthemum cultivars. Nineteen EcoRI/MseI primer combinations revealed 452 informative polymorphic bands with a mean of 23.8 bands and 71.5% polymorphic rate per primer pair. Jaccard’s coefficient of similarity varied from 0.64 to 0.89, indicating much genetic variation in chrysanthemums. The 74 accessions were classified into two major groups by unweighted pair group method with the arithmetic averages (UPGMA). The dendrogram showed that AFLP variability was closely correlated with both geographic distribution and traditional classification of the wild accessions. Among all accessions, genetic relationship was the most relevant factor in AFLP-marker clustering, whereas petal type was also informative. AFLP technology could be very efficient for discriminating species of chrysanthemum and its related genera and reconstruct their genetic relatedness.
Comparing the Adequacy of Controlled-release and Water-soluble Fertilizers for Bedding Plant Production
Authors: Camberato Diane M. , Camberato James J. , Lopez Roberto G.
Published: February 2019

Four complete water-soluble fertilizer (WSF) formulations including micronutrients applied at 200 mg·L−1 nitrogen (N) at each irrigation [Peters Excel (21N–2.2P–16.5K), Daniels (10N–1.8P–2.5K), Peters Professional (15N–1.3P–20.8K), and Jack’s Professional (20N–1.3P–15.7K)] were compared with two controlled-release fertilizer (CRF) products (also containing micronutrients) substrate incorporated at transplant at a rate of 3000 g·m−3 of substrate [Osmocote Plus (15N–4P–9.9K, 90 to 120 days longevity at 21 °C) and Osmocote Bloom (12N–3.1P–15K, 60 to 90 days longevity at 21 °C)] in the greenhouse production of four commonly produced bedding plant species with high alkalinity irrigation water (pH 7.1, 280 mg·L−1 CaCO3 equivalent). Species included Argyranthemum frutescens (L.) Sch. Bip. ‘Madeira Cherry Red’ and iron-inefficient Calibrachoa Cerv. hybrid ‘Cabaret Pink Hot’, Diascia barberae Hook. f. ‘Wink Coral’, and Sutera cordata Roth ‘Abunda Giant White’. Additional treatments included a combination of 100 mg·L−1 Excel and 2100 g·m−3 Osmocote Plus and an Osmocote Plus treatment irrigated with reduced alkalinity water (acidified to pH 6.3, 92 mg·L−1 CaCO3 equivalent). Bedding plants were evaluated at the end of a finish or market stage (3 or 5 weeks depending on species) for shoot dry mass (SDM) and root dry mass (RDM), tissue nutrient concentrations, and visual quality rating (0 to 4). At 3 weeks, there were no significant differences in SDM and RDM between fertilizer treatments for any of the four species. Shoot dry mass significantly increased at 5 weeks in the WSF and combination treatments over the three CRF only treatments for Argyranthemum and over the non-acidified Osmocote Plus treatment only for Calibrachoa. At finish, 3 weeks for Sutera and Diascia and 5 weeks for Argyranthemum and Calibrachoa, visual quality rating for all species was lowest when using Osmocote Plus with or without acidified irrigation water compared with the WSF treatments, except the Daniels treatment in Argyranthemum, which also resulted in a low visual quality rating. Leaf tissue N for all species and phosphorus (P) for all except Diascia were below the recommended range for bedding plant crops in the CRF treatments, which was reflected by the lower substrate electrical conductivity (EC) for the CRF alone and combination treatments. Leaf tissue N and P were related to visual quality rating for all species, leaf tissue potassium (K) for Argyranthemum and Calibrachoa only, and leaf tissue iron (Fe) for Diascia only.
Increasing Nitrogen Availability at Veraison through Foliar Applications: Implications for Leaf Assimilation and Fruit Ripening under Source Limitation in ‘Chardonnay’ (Vitis vinifera L.) Grapevines
Authors: Tozzini Letizia , Sabbatini Paolo , Howell G. Stanley
Published: February 2019

Viticulture in Michigan is often limited by cool and humid climate conditions that impact vine growth and the achievement of adequate fruit quality at harvest. Sugars, pH, acids, and yeast available nitrogen (YAN) are indices of quality and, as such, of suitability for wine production. The aim of this study was to evaluate the efficacy of foliar nitrogen (N) fertilization applied as a 1% w/v urea solution at veraison as a method to increase canopy N availability during the fruit ripening stage. To test the effect on different source sink conditions, we imposed three levels of defoliation (0%, 33%, and 66% of leaves removed per vine) and measured net photosynthetic rate (Pn), leaf efficiency parameters, yield components, and fruit quality parameters. Apical leaf Pn was increased by the 33% defoliation (+12% from the undefoliated control) and by the urea application (+6%) 2 weeks after veraison. In basal leaves we observed a reduction in chlorophyll content (SPAD) and maximum photochemical efficiency of PSII (Fv/Fm) as a result of the defoliation treatment and secondarily by the N application, which resulted in a reduction in Pn. Therefore, mean shoot Pn was unaffected by the treatments. Although neither main nor lateral shoot growth was increased by any defoliation treatment, both percent soluble solids (%SS) and berry weight were significantly reduced by the 66% defoliation treatment. Application of urea increased yeast available amino acids by 20% but did not impact %SS or other chemical parameters indicating a different accumulation pathway for sugars and amino acids in the berry.