bluuebunny/crossref_metadata_2025 huggingface dataset:
Elemental Sulfur Reduces to Sulfide in Black Layer Soil
Authors: Berndt William L. , Vargas Joseph M.
Published: February 2019

Black layer (BL) has reduced the quality of many putting greens since the 1980s. Initially, the nature of BL was unknown. Research established that BL was sulfide (S2−) formed in response to low redox. Its formation was linked to dissimilative sulfate reduction using labeled sulfate (35SO4
2−). The objective of this study was to see if elemental sulfur (S0) reduced to S2−. When labeled sulfur (35S0) with a specific activity of 3.7 × 104 Bq·mg−1 was added to soil from a green with BL in a reaction vessel kept at a low redox potential, it reduced at a per-minute rate of 5.3 nmol·cm−3, resulting in accrual of labeled hydrogen sulfide (H2
35S) and acid-soluble sulfide (AS35S). Nearly 32% of the 35S0 reduced to labeled sulfide (35S2–) in 24 h. Adding S0 to greens with low redox may result in rapid formation of S2– and an accelerated rate of BL development. Avoiding this requires limiting the input of S0 or encouraging high soil redox through chemical or physical means such as fertilizing with nitrate (NO3
–) and aerifying. This is the first report implicating S0 reduction as a source of BL development in putting green soil.
Vegetable Grafting: History, Use, and Current Technology Status in North America
Authors: Kubota Chieri , McClure Michael A. , Kokalis-Burelle Nancy , Bausher Michael G. , Rosskopf Erin N.
Published: February 2019

Grafting of vegetable seedlings is a unique horticultural technology practiced for many years in East Asia to overcome issues associated with intensive cultivation using limited arable land. This technology was introduced to Europe and other countries in the late 20th century along with improved grafting methods suitable for commercial production of grafted vegetable seedlings. Later, grafting was introduced to North America from Europe and it is now attracting growing interest, both from greenhouse growers and organic producers. Grafting onto specific rootstocks generally provides resistance to soilborne diseases and nematodes and increases yield. Grafting is an effective technology for use in combination with more sustainable crop production practices, including reduced rates and overall use of soil fumigants in many other countries. Currently, over 40 million grafted tomato seedlings are estimated to be used annually in North American greenhouses, and several commercial trials have been conducted for promoting use of grafted melon seedlings in open fields. Nevertheless, there are issues identified that currently limit adoption of grafted seedlings in North America. One issue unique to North America is the large number of seedlings needed in a single shipment for large-scale, open-field production systems. Semi- or fully-automated grafting robots were invented by several agricultural machine industries in the 1990s, yet the available models are limited. The lack of flexibility of the existing robots also limits their wider use. Strategies to resolve these issues are discussed, including the use of a highly controlled environment to promote the standardized seedlings suitable for automation and better storage techniques. To use this technology widely in North American fresh vegetable production, more information and locally collected scientific and technical data are needed.
Screening for Resistance to Leaf Spot Diseases of Spinach
Authors: Mou Beiquan , Koike Steven T. , du Toit Lindsey J.
Published: February 2019

The entire U.S. Department of Agriculture (USDA) spinach (Spinacia oleracea L.) germplasm collection (338 accessions) and 22 commercial cultivars were evaluated for resistance to leaf spot caused by Stemphylium botryosum in a greenhouse trial with two replications in 2004. The resistant and susceptible accessions identified as well as the 22 commercial cultivars were included in a second test in 2005 with four replications to confirm the results. No genotype was completely resistant (immune) to the disease. However, there were significant differences in disease incidence (percent of plants with leaf spot) and severity (percent diseased leaf area) among the genotypes tested. Two accessions from Turkey, PI 169685 and PI 173809, consistently had low disease incidence and severity ratings. Two Spinacia tetrandra and four Spinacia turkestanica accessions screened in these public germplasm tests were all susceptible. None of the commercial cultivars tested consistently had low disease incidence or severity. There was no significant correlation between disease incidence/severity and leaf type (smooth, semisavoy, or savoy). In addition to the public germplasm evaluated, 138 proprietary spinach genotypes (breeding lines and cultivars) were obtained from seed companies and screened along with 10 accessions from the USDA germplasm collection for resistance to Stemphylium leaf spot and Cladosporium leaf spot (caused by Cladosporium variabile) in a greenhouse in both 2004 and 2005. Significant differences in severity of leaf spot were observed among the genotypes for both diseases. For each disease, there was a significant positive correlation in severity ratings of the genotypes between the 2004 and 2005 trials. Information on the relative resistance (or susceptibility) of the spinach germplasm evaluated in this study should be useful for plant breeders to develop leaf spot-resistant cultivars.
Growth Characteristics of a Small-fruit Dwarf Mutant Arising from Bud Sport Mutation in Japanese Persimmon (Diospyros kaki Thunb.)
Authors: Yamane Hisayo , Ichiki Megumi , Tao Ryutaro , Esumi Tomoya , Yonemori Keizo , Niikawa Takeshi , Motosugi Hino
Published: February 2019

Fruit size is one of the most important traits that affect the economic value of fruit. In persimmon (Diospyros kaki Thunb.), somatic and bud-sport mutations that affect the fruit traits are frequently observed. Recently, a small-fruit mutant, ‘Totsutanenashi’ (TTN), was discovered in Japan as a bud-sport mutant of the leading cultivar Hiratanenashi (HTN). In this study, we investigated the morphological and physiological characteristics of TTN and HTN focusing on the tree architecture, fruit size, and the fruit flesh chemical composition. The objectives of the study were to evaluate the potential horticultural use of TTN and to characterize the differences between HTN and TTN. Both TTN and HTN are nonaploid plants, indicating that a difference in ploidy is not the cause of the small-fruit mutation. The vegetative growth of trees and tissue-cultured shoots of TTN was more compact than that of HTN. The floral organs of TTN appeared similar to those of HTN before flowering, but the TTN flowers opened earlier, resulting in smaller ovaries than in HTN flowers. The fruit size of TTN was consistently lower than that of HTN at all fruit developmental stages. TTN fruit had a higher sugar content and a higher proportion of sucrose to total sugars than HTN fruit. TTN fruits contained lower levels of secondary metabolites such as soluble tannins and ascorbate than HTN fruits. These results suggest that the fruit size mutation also affects the fruit biochemistry, leading to alterations in the fruit flesh composition. TTN may be a valuable genetic resource because compact trees require less labor and maintenance, and small, sweeter fruits may meet the various needs of consumers. The use of TTN in studies of the genetic control of fruit size is also discussed.
Measuring the Willingness-to-pay for a Horticulture Therapy Site Using a Contingent Valuation Method
Authors: Lee Choong-Ki , Park Sin-Ae , Mjelde James W. , Kim Tae-Kyun , Cho Jae-Hwan
Published: February 2019

Previous research has shown horticultural therapy (HT) provides both physical and mental benefits to those engaged in the gardening activities. Individuals' willingness-to-pay (WTP) for these benefits, however, is unknown because of the lack of well-defined markets for HT. As such, this study estimates individuals' mean WTP for a HT site in Busan, South Korea. Mean WTP is ≈$170/month U.S. per individual. WTP, however, shows a wide dispersion; the standard deviation of the estimated WTP is ≈$60 U.S. This study provides additional information to the policymakers of Busan concerning the issue of developing a horticultural site for its citizens. This information must be weighed against the costs of developing the site.
Plant Productivity in Response to LED Lighting
Authors: Massa Gioia D. , Kim Hyeon-Hye , Wheeler Raymond M. , Mitchell Cary A.
Published: February 2019

Light-emitting diodes (LEDs) have tremendous potential as supplemental or sole-source lighting systems for crop production both on and off earth. Their small size, durability, long operating lifetime, wavelength specificity, relatively cool emitting surfaces, and linear photon output with electrical input current make these solid-state light sources ideal for use in plant lighting designs. Because the output waveband of LEDs (single color, nonphosphor-coated) is much narrower than that of traditional sources of electric lighting used for plant growth, one challenge in designing an optimum plant lighting system is to determine wavelengths essential for specific crops. Work at NASA's Kennedy Space Center has focused on the proportion of blue light required for normal plant growth as well as the optimum wavelength of red and the red/far-red ratio. The addition of green wavelengths for improved plant growth as well as for visual monitoring of plant status has been addressed. Like with other light sources, spectral quality of LEDs can have dramatic effects on crop anatomy and morphology as well as nutrient uptake and pathogen development. Work at Purdue University has focused on geometry of light delivery to improve energy use efficiency of a crop lighting system. Additionally, foliar intumescence developing in the absence of ultraviolet light or other less understood stimuli could become a serious limitation for some crops lighted solely by narrow-band LEDs. Ways to prevent this condition are being investigated. Potential LED benefits to the controlled environment agriculture industry are numerous and more work needs to be done to position horticulture at the forefront of this promising technology.
Vegetative Characterization of Wild Grapevines (Vitis spp.) Native to Puebla, Mexico
Authors: Franco-Mora Omar , Morales-Rosales Edgar Jesús , González-Huerta Andrés , Cruz-Castillo Juan Guillermo
Published: February 2019

Thirty-four accessions of wild grapevines, native to three regions of the state of Puebla, Mexico, that is Teziutlán, Tehuacán, and Atlixco, were vegetatively characterized with 32 suggested IPGRI, UPOV, and OIV descriptors related to young shoot (YS), mature shoot (MS), young leaf (YL), mature leaf (ML), and woody shoot (WS). Excepting profile and absence of sinus teeth in ML, the remaining parameters showed variation among the accessions. After the performance of a correlation analysis among the 32 characters, only those closely correlated were used; that is, for MS: color of dorsal side of node, density of prostrate trichomes of internode; for YL: density of prostrate trichomes between veins and density of erect trichomes on main veins; and for ML: general shape of petiole sinus and the density of erect trichomes on veins in mature leaves. With those six characters, six principal components explained the total variability observed. The most closely related descriptors for principal Component 1 were the ML general shape of petiole sinus (−0.735) and the YL density of erect trichomes on main veins (0.659), whereas for principal Component 2, the MS color of the dorsal side of the node (0.677) and the density of erect trichomes in ML (0.596) were the most highly related. A cluster analysis identified four groups with a euclidean distance of 18; except for plant 183, the other six included in Group 1 were native to the regions Atlixco and Tehuacán; Group 2 was formed by plants native to the three regions, whereas Group 3 was formed by plants native to Teziutlán and Atlixco; Group 4 was formed only by Plant 36, native to Atlixco. These results show that variation among accessions occurs within and among the three states of the Puebla region.
Heat Unit Model for Predicting Bloom Dates in Rubus
Authors: Black Brent , Frisby James , Lewers Kimberly , Takeda Fumiomi , Finn Chad
Published: February 2019

‘Navaho’ and ‘Apache’ blackberry plants were maintained at 10, 15, 20, 25, 30, or 35 °C in growth chambers to determine optimum temperature for budbreak and flowering (fewest days to flowering). In a separate experiment, bloom dates were observed for a collection of 117 Rubus genotypes over four seasons. Using these phenological data, predictive linear and curvilinear models were tested using a range of cardinal temperatures. The growth chamber experiment indicated optimum temperatures for bloom were 25.6 °C for ‘Apache’ and 29.2 °C for ‘Navaho’. For the field observations, time to bloom was best defined by a linear model with base and optimum temperatures of 6 and 25 °C and a curvilinear model defined by base and optimum temperatures of 4 and 27 °C, respectively. Based on the linear growing degree hour (GDH) model, heat units to bloom varied among cultivars in the collection from 9,200 GDH for ‘Chickasaw’ to 18,900 GDH for ‘Merton Thornless’.
Gardenia jasminoides Height Control Using a Photoselective Polyethylene Film
Authors: Lykas Christos , Kittas Constantinos , Katsoulas Nikolaos , Papafotiou Maria
Published: February 2019

The use of chemical growth retardants is a standard practice for compact gardenia plant production. The aim of this study was to investigate the possibility of using a photoselective polyethylene greenhouse covering film as an alternative to chemical treatment for production of compact potted gardenia (Gardenia jasminoides Ellis) plants. Two types of experiments were carried out: 1) on gardenia cuttings rooted in rooting benches; and 2) on young potted plants grown under low tunnels. In both experiments, two types of cover materials were used: 1) a photoselective polyethylene (P-PE), filtering light within the wavelength range 600 to 750 nm; and 2) a common polyethylene film (C-PE) routinely used in greenhouse practice. Values of photosynthetically active radiation (in a wavelength of 400 to 700 nm), cover materials' spectral properties (in a wavelength range of 400 to 1100 nm), air temperature, and relative humidity were recorded inside the rooting benches and under the low tunnels. Plant growth parameters (main shoot length and leaf area and lateral shoot number, leaf area, and fresh and dry weight) were determined along the growth cycle. Cuttings rooted under the P-PE film received light with high ζn values (ratio of Rn: 655 to 665 nm to far red FRn: 725 to 735 nm) and high blue (B: 400 to 500 nm) to red (R: 600 to 700 nm) ratio (B:R) and were 68.7% shorter and had 21% lower leaf area compared with cuttings rooted under the C-PE film. Similarly, plants that were rooted and then grown under the low tunnels covered with the P-PE film, compared with plants rooted and grown under C-PE film, were 59% shorter, had 85% lower leaf area, 89% lower fresh weight, and 86% lower dry weight, whereas they did not produce lateral shoots. However, plants rooted under the C-PE film and then grown under the P-PE-covered low tunnels were 26% shorter and developed fewer laterals than plants rooted and grown under tunnels covered with C-PE film. Finally, plants rooted under the P-PE film and then grown under tunnels covered with C-PE film developed into compact, well-shaped plants, because they had a drastic reduction of height (56%) without an effect on leaf area, shoot and leaf fresh and dry weight, and the number of lateral shoots.
Electrodegradation of Root Exudates to Mitigate Autotoxicity in Hydroponically Grown Strawberry (Fragaria ×ananassa Duch.) Plants
Authors: Asao Toshiki , Kitazawa Hiroaki , Ban Takuya , Pramanik M. Habibur Rahman , Tokumasa Kenzi
Published: February 2019

Root exudates from strawberry plants are known to cause autotoxicity and benzoic acid (BA), a potent growth inhibitor, was found in the exudate. BA (400 μm) was easily decomposed by electrodegradation (ED) treatment at 10.0 V and 2.0 A after the addition of BA into nutrient solution. The growth of strawberry plantlets in nutrient solution containing BA (400 μm) or in control nutrient solution varied significantly depending on the use of ED treatment. The growth inhibition of plantlets in the BA-containing nutrient solution or in nutrient solution used for strawberry culture was significantly ameliorated by ED treatment. This growth recovery resulting from ED treatment was most pronounced in terms of the yield of strawberry fruit. These results suggest that ED treatment of the culture nutrient solution could result in the decomposition of toxic root exudates, including BA from strawberry plants, and mitigates the autotoxicity observed in closed hydroponic culture. In addition, the supplementation of Fe-EDTA is recommended after ED treatment as a result of the rapid decomposition of Fe-EDTA by ED.
Antioxidant Capacity and Phenolic Antioxidants of Midwestern Black Raspberries Grown for Direct Markets Are Influenced by Production Site
Authors: Ozgen Mustafa , Wyzgoski Faith J. , Tulio Artemio Z. , Gazula Aparna , Miller A. Raymond , Scheerens Joseph C. , Reese R. Neil , Wright Shawn R.
Published: February 2019

Black raspberries (Rubus occidentalis L.) are rich in phytonutrients that have demonstrated chemoprotective properties against certain degenerative diseases. To estimate variability in phytonutritional quality among sources of black raspberry, 19 samples representing four common midwestern cultivars obtained from eight production sites were assayed for their antioxidant capacity [2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing ability of plasma (FRAP) methods], total phenolic content (TP), total monomeric anthocyanin levels (TMA), and levels of cyanidin 3-rutinoside. The antioxidant potential among samples averaged 2.92 ± 0.29 and 4.62 ± 0.88 mmol TE·100 g−1 fresh weight by the DPPH and FRAP methods, respectively; TP, TMA, and cyanidin 3-rutinoside means averaged 449 ± 62, 336 ± 109, and 244 ± 84 mg·100 g−1 fresh weight, respectively. Levels of FRAP, TP, TMA, and cyanidin 3-rutinoside were strongly correlated (r = +0.85 to +0.96). Mean antioxidant capacities and phenolic constituent levels were similar among ‘Bristol’, ‘Jewel’, and ‘MacBlack’ samples; values for a single sample of ‘Haut’ were lower but comparable to levels found in individual samples of the other three cultivars. Black raspberry production site differences were statistically significant for FRAP, TMA, cyanidin 3-rutinoside, and titratable acidity (TA) levels. Inverse relationships (r = –0.65 to –0.74) among black raspberry samples for FRAP, TMA, or cyanidin 3-rutinoside levels versus levels of TA suggested that site differences may be partially attributable to fruit ripeness at harvest. Relationships among these parameters versus regional differences in soil temperatures were also significant but weak. Regardless of its environmental or physiological drivers, point-source variation in fruit phytonutrient contents may be a relevant concern in health-related studies or clinical applications. Moreover, it may impact the nutritional benefits to the consumer and affect the quality advantages associated with direct-marketed black raspberries.
Further Evidence of a Genetic Basis for Varied Levels of Injury to Sweet Corn Hybrids from Cytochrome P450-metabolized Herbicides Applied Postemergence
Authors: Williams Martin M. , Wax Loyd M. , Pataky Jerald K. , Meyer Michael D.
Published: February 2019

Over the last two decades, sweet corn injury from postemergence herbicides has resulted in routine screening of combinations of new and existing hybrids and herbicides. Sensitivity of sweet corn to several cytochrome P450-metabolized herbicides is simply inherited and has a common genetic basis, a single P450 locus that may account for a large amount of the variation in sweet corn injury commonly observed among screening trials. Using data from 13 hybrid-herbicide screening trials, the objective of this work was to determine the extent to which injury from P450-metabolized herbicides was associated with the genotypes of hybrids at a locus affecting herbicide sensitivity. Of the 703 hybrids evaluated in the University of Illinois sweet corn hybrid nurseries from 2002 to 2007, previous work showed that a total of 104, 70, and nine of the hybrids were known to be homozygous-tolerant, heterozygous, or homozygous-sensitive, respectively, for an allele affecting herbicide response. Nurseries from 2002 to 2007 included six trials with mesotrione, three trials with nicosulfuron, and one trial each with foramsulfuron, tembotrione, halosulfuron, and carfentrazone. When means of hybrids in genotypic classes were compared, homozygous-sensitive hybrids were consistently injured more severely than homozygous-tolerant and heterozygous hybrids. When environmental conditions favored crop injury, heterozygous hybrids had an intermediate response that was closer to homozygous-tolerant hybrids than homozygous-sensitive hybrids. These data are further evidence that the probability of injury from several P450-metabolized herbicides, including mesotrione, nicosulfuron, foramsulfuron, tembotrione, halosulfuron, and carfentrazone, is highest in homozygous-sensitive hybrids and least in homozygous-tolerant hybrids and that variability of responses among sweet corn hybrids to these P450-metabolized herbicides can be explained largely by the genotype of a hybrid at a single locus.
Nitrate-N Concentrations in the Soil Solution Below Reuse Irrigated Golf Course Fairways
Authors: Devitt Dale A. , Wright Lena , Bowman Daniel C. , Morris Robert L. , Lockett Michelle
Published: February 2019

Irrigators in arid and semiarid regions that use reuse water must maintain positive leaching fractions (LFs) to minimize salt buildup in root zones. However, with the continuous feed of NO3-N in reuse water, imposing LFs can also lead to greater downward movement of NO3-N. It is therefore essential that deep movement of NO3-N be assessed relative to nitrogen loading under such conditions. We conducted a long-term monitoring program on nine golf course fairways in southern Nevada over a 1600-d period. The fairways were predominantly bermudagrass [Cynodon Dactylon (L.) Pers.; 35 of 36 site × years] overseeded with perennial ryegrass (Lolium perenne L.; 8 of 9 courses). Courses were irrigated with fresh water, reuse water (tertiary treated municipal sewage effluent), or transitioned to reuse water during the study. Solution extraction cups were inserted at depths of 15, 45, 75, and 105 cm on fairways and sampled and analyzed for NO3-N on a monthly basis. Distribution patterns of NO3-N varied from site to site. Concentrations exceeding 100 mg·L−1 were observed at the 105-cm depth on all three long-term reuse courses. On the transitional courses, 72% of the variation in the yearly average NO3-N concentrations at the105-cm depth could be accounted for based on knowing the amount of fertilizer nitrogen (N) applied, the amount of reuse N applied, and the LF (Y = –42.5 + 0.18 fertilizer N + 0.26 reuse N –62.0 LF). Highest N fertilizer applications occurred on transition courses with little or no reduction in N applications after courses had transitioned to reuse water (pretransition courses 394 + 247 kg·ha−1 N/year versus posttransition courses 398 + 226 kg·ha−1 N/year). The results of this study indicate a need for a more scientific approach to N management on reuse irrigated courses.
Regulation of Root Distribution and Depth by Phosphorus Localization in Agrostis stolonifera
Authors: Lyons Eric M. , Snyder Robert H. , Lynch Jonathan P.
Published: February 2019

Root distribution in turfgrass systems influences drought tolerance and resource competition with undesirable species. We hypothesized that spatial localization of phosphorus (P) supply would permit manipulation of turfgrass root distribution. To test this hypothesis, creeping bentgrass (Agrostis stolonifera L.) plants were exposed to localized P supply in two experiments. The first experiment split the root zone horizontally into two different growth tubes and the second used alumina-buffered P (Al-P) to localize P availability deeper within a continuous root zone. In the horizontally split root zones, heterogeneous P availability led to no difference in shoot growth compared with uniform P availability. Root proliferation was greatest in the growth tube with available P compared with the growth tube without P. The use of Al-P, regardless of its spatial distribution, doubled root-to-shoot ratios compared with soluble P. Much of the increase in the ratio was accounted for by reduced shoot growth. Use of Al-P increased rooting deeper in the root zone, especially when the Al-P was mixed only in the lower portion of the root zone. Our results are consistent with the hypothesis that root distribution of creeping bentgrass can be manipulated by spatial localization of P supply in the root zone and indicate that relative biomass allocation to roots and shoots may be manipulated with buffered P sources.
Thai Tiger™ Series of Low-chill Peaches for the Subtropics
Authors: Byrne David H. , Boonprakob Unaroj
Published: February 2019

The Thai Tiger series of low-chill peaches are being released for use in subtropical or tropical highland regions and particularly for use in the northern highlands of Thailand to expand the harvest season of the present low-chill variety grown, ‘EarliGrande’. The Thai Tiger series are yellow-fleshed acid-sweet peach varieties that produce excellent yields of firm peaches and will allow a continuous harvest from early April until early May in the northern highlands of Thailand.
Effectiveness of Colchicine and Oryzalin at Inducing Polyploidy in Watsonia lepida N.E. Brown
Authors: Ascough Glendon D. , van Staden Johannes , Erwin John E.
Published: February 2019

Genetic modification and manipulation offers the possibility of introducing novel traits into existing plants, thereby increasing marketability. Polyploid induction has in the past produced plants that are more compact and have larger flowers, leaves, and fruit, making them more desirable to consumers. The effect of pulse treatments (0, 24, 48, and 72 h) of colchicine (25, 50, 125, and 250 μm) or oryzalin (30, 60, 90, and 120 μm) on in vitro-grown Watsonia lepida N.E. Brown shoots was investigated. Explant survival was higher and more consistent with oryzalin treatment compared with treatment with colchicine. More mixoploids than tetraploids were produced with both compounds. The optimum treatment for producing tetraploids was 120 μm oryzalin for 24 h. Of the 30% explants that survived this treatment, 33% were found to be stable tetraploids.
Effect of Potassium Nitrate Priming on Seed Germination of Seashore Paspalum
Authors: Shim Sang In , Moon Jun-Cheol , Jang Cheol Seong , Raymer Paul , Kim Wook
Published: February 2019

Germination of seashore paspalum (Paspalum vaginatum Swartz) is a critical factor influencing seedling establishment when seeded directly in fields. In this research, pregermination priming with osmotic solution was used to improve the germination percentage of seashore paspalum. The goal of this study was to develop techniques that improve the germination of a seashore paspalum cultivar (SeaSpray). Seeds were subjected to priming in petri dishes with solutions of KNO3 at 25 °C for 24, 48, and 72 h in growth chambers. Germination percentage differed by priming duration as well as concentration of priming media. Based on the germination percentage 14 days after imbibition, the most promising priming condition was the treatment with 0.2% or 0.5% KNO3 for 72 h at a constant temperature of 30 °C and 0.2% or 0.5% KNO3 for 48 to 72 h at alternating temperature of 25/35 °C. Both concentrations showed reasonable germination percentage greater than 85% at alternating temperature condition. Priming with KNO3 solution for 48 to 72 h improved not only germination percentage, but also uniformity. The increased duration of priming with KNO3 was positively correlated with an improved germination percentage. The effect of increasing concentration was the most apparent at a constant temperature (30 °C) regime with the treatment of 0.2% KNO3 priming. Germination percentage was increased from 34.3% to 68.0% 2 weeks after imbibition (WAI) as the priming duration was increased from 24 to 72 h. Priming with KNO3 for 3 days also had a modest effect on germination percentage (greater than 74.7%) at 1 WAI. Therefore, priming with 0.2% or 0.5% solution of KNO3 for 72 h is a recommended method that can be practically applied for increasing germination of paspalum under an alternating temperature (25/35 °C) condition. The regression analysis between odds of germination percentage and germination time showed that priming treatment increased internal activities during the second stage of seed germination.
Plant Performance and Nutrient Losses during Containerized Bedding Plant Production Using Composted Dairy Manure Solids as a Peat Substitute in Substrate
Authors: Shober Amy L. , Wiese Christine , Denny Geoffrey C. , Stanley Craig D. , Harbaugh Brent K. , Chen Jianjun
Published: February 2019

Recent concerns over the environmental impact of peat harvesting have led to restrictions on the production of peat in Florida and other areas. The objectives of this study were to evaluate the use of composted dairy manure solids as a substitute for sphagnum or reed-sedge peat in container substrates on the growth of Solenostemon scutellarioides L. Codd ‘Wizard Velvet’, Tagetes patula L. ‘Safari Queen’, and Begonia ×hybrida ‘Dragon Wing Red’ and to examine the nutrient content in leachate from pots. Plants were grown for 5 weeks in a greenhouse in 15-cm plastic pots with seven substrates containing various proportions of sphagnum peat (S) or reed-sedge peat (R) and composted dairy manure solids (C), each with 20% vermiculite and 20% perlite. Substrate composition had no effect on plant quality ratings, number of flowers, or root dry mass for any of the plant species evaluated. Substrate composition did not affect the growth index (GI) or shoot dry mass of S. scutellarioides ‘Wizard Velvet’ or the GI of T. patula ‘Safari Queen’. However, growth of B. ×hybrida ‘Dragon Wing Red’ (GI and shoot dry mass) and T. patula ‘Safari Queen’ (shoot dry mass only) was highest in the 3S:0R:0C substrate. The substrates containing sphagnum peat and/or composted dairy manure solids (3S:0R:0C, 2S:0R:1C and 1S:0R:2C) had the highest NH4-N losses through the first 7 d of production. The 0S:3R:0C substrate had the highest initial leachate NO3+NO2-N losses and this trend persisted throughout most of the production cycle. Significantly more dissolved reactive phosphorus was leached from substrate mixes containing composted dairy manure solids than mixes containing only sphagnum or reed-sedge peat materials through 19 d after planting. All substrates tested as part of this study appeared to be commercially acceptable for production of container-grown bedding plant species based on plant growth and quality. However, nutrient losses from the containers differed depending on the peat or peat substitute used to formulate the substrates.
A Rapid Technique for Multiple-race Disease Screening of Phytophthora Foliar Blight on Single Capsicum annuum L. Plants
Authors: Monroy-Barbosa Ariadna , Bosland Paul W.
Published: February 2019

Phytophthora blight, caused by the oomycete Phytophthora capsici Leon., is a major disease that threatens production and long-term viability of the chile pepper (Capsicum annuum L.) industry. For each phytophthora disease syndrome such as root rot, foliar blight, and stem blight separate and independent resistant systems have evolved in the host. In addition, several physiological races of the pathogen have been identified. A novel, effective, and accurate screening technique is described that allows for multiple races to be evaluated on a single plant of C. annuum. The P. capsici resistant line Criollo de Morelos-334, a susceptible cultivar, Camelot, and three New Mexico Recombinant Inbred Lines, -F, -I, -S, were used to evaluate the new technique for phytophthora foliar blight multiple-race screening. Using three P. capsici physiological races, no interaction among the physiological races was observed with this technique. This novel technique provided a rapid disease screen evaluating multiple physiological races for phytophthora foliar blight resistance in a single chile pepper plant and can assist plant breeders in selecting for disease-resistant plants.
Evaluation of Roses from the Earth-Kind® Trials: Black Spot (Diplocarpon rosae Wolf) Resistance and Ploidy
Authors: Zlesak David C. , Whitaker Vance M. , George Steve , Hokanson Stan C.
Published: February 2019

Regional, replicated cultivar trials of landscape roses are an ongoing component of the Earth-Kind® program, which was started at Texas A&M University in the 1990s to support environmental landscape stewardship. The rose trials within the Earth-Kind program identify and promote the most regionally adapted rose cultivars and are conducted without fertilizers or pesticides and greatly reduced irrigation. Black spot (caused by Diplocarpon rosae Wolf) is the most serious disease of outdoor-grown roses worldwide as a result of the potential for rapid leaf yellowing and defoliation. Earth-Kind designated cultivars for the south–central United States and roses under trial in other regions or considered for future Earth-Kind trials (n = 73 roses) and two susceptible control cultivars were challenged with North American Races 3, 8, and 9 of D. rosae, which were previously characterized at the University of Minnesota. Young expanded leaves were inoculated using detached leaf assays. Lesion length (LL) was measured for susceptible reactions and cultivar ploidy was determined using root tip squashes. Diploid, triploid, and tetraploid cultivars (n = 20, 30, and 23, respectively) were identified, and race-specific resistances and partial resistances were also identified. Race-specific resistance was generally more prevalent in newer rose cultivars and rose cultivars more recently included in Earth-Kind trials. Nine cultivars were resistant to all three races (Brite Eyes™, ‘Grouse’, Home Run®, Knock Out®, Paprika™, Peachy Cream™, Pink Knock Out®, Rainbow Knock Out®, and Yellow Submarine™). Blushing Knock Out®, a sport of Knock Out®, was susceptible to Race 8. Partial resistance rank for LL was generally consistent across races for roses susceptible to multiple races. The application of these data includes: characterizing the minimum resistance level needed for roses to warrant inclusion in Earth-Kind field trials, the identification of additional race-specific resistance genes, identifying resistance-breaking isolates of D. rosae, understanding race composition in field trials based on infection patterns of key cultivars, selection of parents for resistance breeding efforts, and continued comparisons between LL and growing bodies of Earth-Kind field resistance data.
Physiology and Growth of Containerized Coastal Douglas Fir Seedlings Given Different Durations of Short Days to Induce Dormancy
Authors: MacDonald Joanne E. , Owens John N.
Published: February 2019

We compared the effects of different durations of short days (SDs) as a dormancy-induction regime on bud development, bud endodormancy, and morphology of first-year containerized coastal douglas fir [Pseudotsuga menziesii (Mirb.) Franco var. menziesii] seedlings in the nursery together with seedling survival and growth after one growing season in a common garden. In early July, four durations of 8-h SDs were applied: 3, 4, 5, and 6 weeks. During the first week of SDs, budscale initiation started and was completed; then initiation of needles for next year's leading shoot (leader) began. Needle initiation was completed 10 weeks after the start of the regime in seedlings given 5 or 6 weeks of SDs and 13 weeks for those given 3 or 4 weeks of SDs. In early October, duration of SDs had no effect on bud endodormancy; 50% to 88% of terminal buds were endodormant. On this date, seedling height and shoot dry weight were unaffected by duration of SDs, whereas root dry weight and shoot diameter were significantly reduced in seedlings given 6 weeks of SDs compared with other durations. After one growing season, duration of SDs had no effect on seedling survival, leader length, shoot dry weight, root dry weight, or shoot diameter. We recommend the 3-week duration of SDs for coastal douglas fir crops.
Greenhouse Cucumber Growth and Yield Response to Copper Application
Authors: Zheng Youbin , Wang Linping , Cayanan Diane Feliciano , Dixon Mike
Published: February 2019

To determine the nutrient solution copper (Cu2+) level above which Cucumis sativus L. (cucumber, cv. LOGICA F1) plant growth and fruit yield will be negatively affected, plants were grown on rockwool and irrigated with nutrient solutions containing Cu2+ at 0.05, 0.55, 1.05, 1.55, and 2.05 mg·L−1. Copper treatment began when plants were 4 weeks old and lasted for 10 weeks. During this 10-week period, plants were harvested at 3 weeks (short-term) and 10 weeks (long-term) after the start of Cu2+ treatment. Neither visible leaf injury nor negative Cu2+ effect was observed on plant growth (leaf number, leaf area, leaf dry weight, and stem dry weight) after 3 weeks of continuous Cu2+ treatment. However, after 10 weeks of continuous Cu2+ application, cucumber leaf dry weight was significantly reduced by Cu2+ levels 1.05 mg·L−1 or greater; leaf number, leaf area, and stem dry weight were significantly reduced by Cu2+ levels 1.55 mg·L−1 or greater. Copper (Cu2+ levels 1.05 mg·L−1 or greater) also caused root browning. Some plants under the 2.05 mg·L−1 Cu2+ treatment started to wilt after 6 weeks of continuous Cu2+ treatment. Copper treatment did not result in any change in leaf greenness until after Week 9 from the start of the treatments. There was no sign of a negative Cu2+ effect on cucumber fruit numbers after the first 2 weeks of production, but plants under the highest Cu2+ concentration treatment (2.05 mg·L−1) gradually produced fewer cucumber fruit than the control (0.05 mg·L−1) and eventually resulted in lower cucumber yield. Nutrient solution can be treated with 1.05 mg·L−1 of Cu2+ in cucumber production greenhouses; however, it is not recommended to use Cu2+ concentrations 1.05 mg·L−1 or greater continuously long-term (more than 3 weeks). When applying Cu2+, it is suggested that cucumber roots be examined regularly because roots are a better indicator for Cu2+ toxicity than leaf injury.
Survey of Corylus Resistance to Anisogramma anomala from Different Geographic Locations
Authors: Molnar Thomas J. , Goffreda Joseph C. , Funk C. Reed
Published: February 2019

Anisogramma anomala (Peck) E. Müller is the causal agent of the disease eastern filbert blight (EFB) of hazelnuts (Corylus spp.). Little is known of its genetic diversity and pathogenic variation. Most sources of host resistance have been identified in the Pacific Northwest, a region outside the native range of A. anomala believed to have limited diversity of the fungus due to a long history of quarantine and its relatively recent inadvertent introduction. In an attempt to investigate the pathogenic variation of A. anomala, 12 hazelnut genotypes that showed complete resistance in Oregon were inoculated with 12 isolates collected from across its native range. At the conclusion of the study, ‘Grand Traverse,’ ‘Ratoli’, OSU 541.147, OSU 495.072, and OSU 526.041 remained free of disease. ‘Closca Molla’, OSU 759.007, and OSU 587.044 were infected by most isolates. ‘Gasaway’ was infected by the Michigan isolate, which was also the only one to infect its offspring ‘Zimmerman’, although the lesion lacked sporulating stromata. Interestingly, ‘VR20–11’, another offspring of ‘Gasaway’, was infected by isolates from New Jersey, Minnesota, and Michigan. The Michigan isolate also caused the only signs of infection on OSU 408.040.
Branding Awareness and Willingness-to-pay Associated with the Texas Superstar™ and Earth-Kind™ Brands in Texas
Authors: Collart Alba J. , Palma Marco A. , Hall Charles R.
Published: February 2019

The environmental horticulture industry, also known as the Green Industry, is the second most important sector in the U.S. agricultural economy in terms of economic output and one of the fastest growing segments of agriculture; however, it has shifted from an average annual growth of 13.6% in the 1970s to an annual growth of less than 3% in the 2000s, which suggests the industry is facing a maturing marketplace. As an effort to help the industry stimulate demand, Texas A&M AgriLife developed the Texas Superstar™ and Earth-Kind™ brands. The aims of these plant promotion programs are to increase the demand for selected horticultural products, raise awareness among consumers of Texas-grown plant material, promote environmental responsibility, and increase producers' profitability by providing branding price premiums. Despite the considerable investments on research and marketing done thus far, no research has investigated the effectiveness of these branding efforts in terms of consumer behavior. This article evaluates brand awareness and willingness-to-pay for these two brands in Texas. The discrete choice models used were the Logit and Probit models on brand awareness and the Tobit model on the conditional willingness-to-pay. Results from this study show that consumer awareness of Texas Superstar™ and Earth-Kind™ in Texas is low, but the level of satisfaction among consumers is high. Furthermore, profiles of the consumers' behavioral and demographic characteristics that are more likely to influence brand awareness and willingness-to-pay were identified. The findings suggest that consumers who shop weekly or monthly for ornamental plants are more likely to be aware of programs such as Texas Superstar™ and Earth-Kind™. Also, those who live in South Texas were more likely to exhibit awareness of Earth-Kind™. Consumers who shopped for self-consumption purposes were willing to pay a discounted price for Texas Superstar™ and Earth-Kind™ plants compared with unbranded plants and those who were previously aware of the brands were willing to pay more. The two brands were effective in differentiating their products and thus creating price premiums. It was estimated that the willingness-to-pay for Earth-Kind™ and Texas Superstar™ for the average respondent was 10% higher than the willingness-to-pay for an unbranded plant.
Antioxidant Activity of Fruits Produced in Northern Greece
Authors: Petridis Antonios , Koukourikou Magdalene , Sotiropoulos Thomas , Stylianidis Dimitrios
Published: February 2019

The antioxidant activities (μmol ascorbic acid equivalent/g fresh weight) of the edible part of fruits grown in northern Greece were determined using the ferric-reducing antioxidant power (FRAP) assay. Differences were observed among species as well as cultivars of the same species. Cornelian cherry had the highest FRAP value followed by jujube. Cherries, black grapes, and blackberry showed high activity followed by pears, persimmons, plums, peaches, white grapes, pomegranates, apples, nectarines, kiwifruits, quinces, figs, and apricots.
Micropropagation of Cypripedium formosanum Hayata through Axillary Buds from Mature Plants
Authors: Lee Yung-I
Published: February 2019

A micropropagation protocol for an endangered slipper orchid species, Cypripedium formosanum Hayata, through axillary buds from adult plants has been developed. The season of explant collection is crucial for the initial success of an aseptic culture. Explants collected in the middle of January gave the highest percentage of explant survival (54.2%) and shoot-forming percentage (41.7%). Of the two cytokinins tested, N6-benzyladenine (BA) was found to be superior to thidiazuron for normal shoot formation. The optimum result was obtained in quarter-strength Murashige and Skoog medium containing 22.2 or 44.4 μM BA in which the cultures produced 6.3 and 7.1 shoots per explant with 10.6 to 11.7 mm average length after 90 d of culture. Regenerated shoots rooted for 60 d in the basal medium with 1 g·L−1 activated charcoal and 20 g·L−1 potato homogenate were ready for growth in pots. This is the first report on shoot multiplication in vitro from mature plants of Cypripedium that provides a reliable method for propagating the selected elites.
Mapping for Quantitative Trait Loci and Major Genes Associated with Fresh-cut Browning in Apple
Authors: Sun Rui , Li Hui , Zhang Qiong , Chen Dongmei , Yang Fengqiu , Zhao Yongbo , Wang Yi , Han Yuepeng , Zhang Xinzhong , Han Zhenhai
Published: February 2019

Flesh browning is an important negative trait for quality preservation of fresh-cut fruits. To obtain a better understanding of the inheritance and genetic control of flesh browning in apple, the phenotype of a hybrid population derived from ‘Jonathan’ × ‘Golden Delicious’ was studied for 2 successive years. The inheritance of the flesh browning trait was analyzed by the frequency distribution of the phenotypes. Flesh browning-associated major genes were then mapped by screening genome-wide simple sequence repeat (SSR) markers. Flesh browning is inherited quantitatively and showed a clear bimodal frequency distribution, indicating that the segregation of major genes is involved in the variation. The segregation ratio of light and heavy browning was 7:1 in 2010, 2011, and 2010 + 2011, suggesting that the inheritance of the trait in apple involves three segregated loci of major genes. The heritability of the major gene effect was 72.14% and 72.76% in 2010 and 2011, respectively. SSR markers were screened from 600 pairs of SSR primers located on 17 apple linkage groups (LGs). The three major genes were mapped on LG10, 15, and 17 on the apple genome, respectively, by linkage analysis of flesh browning phenotypes and the genotypes of SSR markers. Two quantitative trait loci (QTLs) for flesh browning were mapped on LG15 of ‘Jonathan’ and LG17 of ‘Golden Delicious’, respectively, which are the same linkage groups that two major genes mapped on.
Effects of Daily Light Integral and Canopy Density on Shoot Growth and Development in a Poinsettia (Euphorbia pulcherrima Willd. ex. Klotsch) Stock Plant Canopy
Authors: Chong Joaquin A. , Samarakoon Uttara C. , Faust James E.
Published: February 2019

Poinsettia stock plants consist of a dense canopy of competing shoots, and the growth and development of these individual shoots have not been previously quantified. The effects of air temperature, daily light integral (DLI), and canopy density (CD) were investigated on poinsettia (Euphorbia pulcherrima Willd. ex. Klotsch) ‘Freedom Red’ shoot development in a stock plant canopy. Plants were grown at two constant temperatures (20.3 or 25.7 °C), five CD (43, 86, 129, 172, or 215 shoots/m2), and three DLI treatments (2.6, 4.4, or 7.7 mol·m−2.d−1 for the September planting and 4.0, 6.0, or 10.6 mol·m−2.d−1 for the January planting). Shoot position at the final data collection was used to assign shoots to different levels within the canopy; Level 1 = the four highest shoots, Level 2 = the next four highest shoots, and so forth for Levels 3, 4, and 5. Temperature did not significantly affect leaf unfolding rate (LUR), shoot fresh mass (FM), or shoot caliper, whereas DLI and CD affected shoot growth and development. LUR and FM increased as DLI increased from 2.6 to 10.6 mol·m−2.d−1, whereas LUR and FM decreased on the uppermost shoots in the canopy, e.g., Level 1 shoots, as CD increased from 43 to 129 shoots/m2. Therefore, higher CD required higher DLI to achieve similar LUR and FM. Shoot caliper on Level 1 shoots increased from 6.3 to 7.4 mm as CD decreased from 129 to 43 shoots/m2; and shoot caliper increased from 5.8 to 7.6 mm as DLI increased from 4.0 to 10.6 mol·m−2.d−1. The DLI environment needs to be managed to accommodate greater CD, to sustain growth and development of individual shoots within the canopy of poinsettia stock plants.