bluuebunny/crossref_metadata_2025 huggingface dataset:
(28) Productivity and Fruit Quality of Bell Pepper under Greenhouse Conditions in Northwest Mexico
Authors: Grijalva-Contreras Raul Leonel , Macias-Duarte Rubén , Robles-Contreras Fabián , de Jesus Valenzuela-Ruiz Manuel
Published: February 2019

Vegetables are important in Mexican agriculture, and production under greenhouse conditions has been increased notably during the past year. The production area is about 3500 ha. The main crop grown in greenhouses is tomatoes, but bell pepper is a potential crop due to high yield and that good quality commands a good price during the winter. The objetive of this research was to evaluate nine bell peppers with high technology for horticultural production in the greenhouse. The experiment was carried out at the Experimental Station (INIFAP-CIRNO). The greenhouse conditions are: polyethylene (8 mL), without temperature control, natural ventilation, and soil condition (electrical conductivity of 1.22 dS·m-1and pH 7.96). The planting date was on 26 Oct. 2004. Plant density used was 3.78 plants/m2. The harvest period ocurred from 3 Mar. to 11 May 2005. In this period, we made six cuttings. There were no differences in the yield among varieties. The varieties with the higher yield were Laroles, Asaia, Far-114 and Cupid, with 65.6, 63.1, 63.1, and 57.4 t·ha-1, respectively. Cadia and Parker had the lowest yield, with 78.5 and 90.0 t·ha-1, respectively. The fruit weight was good in all varieties, however, Far-114 and Asaia had higher fruit weight with 272.5 and 269.5 g, respectively. The main insect pests during this experiment were white fly (Bemissia sp.) and leafminer (Lyriomyza sp.). There were no disease problems during this trial.
(34) Energy and Capital Costs of High Tunnel Construction
Authors: Bomford Michael K. , Silvernail Anthony
Published: February 2019

Commercial vegetable growers in Kentucky have used high tunnels for year-round production for the past decade. They suggest it is a more energy-efficient and economical means of supplying off-season vegetables to the region than trucking field-grown produce from warmer regions. In 2005, we erected a 9 × 12-m high tunnel, designed to comply with National Organic Program standards, at the Kentucky State University Research Farm. We recorded the retail cost of each component, and estimated its embodied energy using published figures for common building materials. The materials used for construction were valued at $2830, and contained 59 GJ of embodied energy. The frame and plastic cladding accounted for 36% and 24% of the total capital cost, and 28% and 37% of the embodied energy, respectively, with other components accounting for the remainder. Assuming that the frame, plastic cladding and other components last 20, 4, and 10 years, respectively, the average cost of the tunnel is $328/year, and the average energy input is 8 GJ/year. The plastic cladding accounts for 50% of the annual amortized cost, and 66% of the embodied energy. If the structure is used to grow 2000 heads of lettuce each winter, and 450 kg of early market tomatoes each spring, it could generate sufficient income to recover the total cost of construction materials in its first year. Trucking this amount of produce from California to Kentucky would consume approximately 8 GJ. We conclude that there is an economic incentive for growers to adopt this technology, but no energy efficiency advantage to society. Longer tunnels, such as the 9 × 29-m models more commonly used by commercial vegetable growers in Kentucky, will be more energy- and capital-efficient.
(288) Determination of Genetic Stability of In Vitro-derived Birch Plants
Authors: Dai Wenhao , Magnusson Victoria , Swanberg Andrea
Published: February 2019

Many woody plants, including some birch species, can be cloned using such in vitro techniques as pre-existing meristem culture, organogenesis, and embryogenesis. However, clonal fidelity of in vitro-derived plants is always a big concern because somaclonal variations may be induced during the entire in vitro process. To address this issue, we used random amplified polymorphic DNA (RAPD) markers to determine the genetic stability of in vitro-propagated plants of Betula platyphylla `Fargo'. Forty-two greenhouse-grown birch plants derived from a 10-year shoot tip culture (shoot-derived) and 42 in vitro plants regenerated from leaf tissues (regenerated) were randomly selected and evaluated for their genetic fidelity by RAPD. To date, 20 primers (C1-C20, Operon Technologies) were screened for all 84 plants. Only strong bands that are conservative were scored. Each primer generated a unique set of amplification products. Most of scoreable bands are ranged from 350 to 1800 bp. A total of 3696 fragments were amplified from 42 shoot-derived plants by all 20 primers with an average of 4.4 bands per primer, in which 6 primers produced polymorphic bands, indicating some genetic variations within shoot-derived plants. Nineteen out of 20 primers yielded 2772 clear and reproducible bands (an average of 3.47 per primer) from 42 regenerated plants with no significant variations being detected. Our preliminary results showed that in vitro regenerated plants are genetically uniform. However, a long-term tissue culture might result in a few genetic variations of birch species.
(292) The Effect of Darkness and Sucrose Concentrations on the Production of Rosmarinic Acid in the Callus of Five Rosemary Genotypes
Authors: El-Naggar Hany M. , Read Paul E. , Cuppett Susan L.
Published: February 2019

Rosemary Rosmarinus officinalis is a member of the Lamiaceae. Rosmarinic acid (RA) is a very strong antioxidant produced in the chloroplast, and used to protect plant tissues against oxidative stress. A number of investigations showed that the sucrose concentration in the callus growing medium greatly influenced the production of secondary metabolites of the phenylpropanoid pathway such as RA. The aim of this study was to test the effect of elevated sucrose concentrations (2%, 3%, 4%, 5%, and 6% sucrose) and the effect of light and dark treatments on the production of RA in the callus of five different genotypes. The genotypes were Majorca, Rosmarinus officinalis, Pine Scented, Madeline Hill, and APR. It was found that the dark treatment produces more RA than the light treatment in all genotypes, and in all sucrose concentrations. The RA concentration increased with increasing the sucrose concentration from 2%—reaching the highest concentration at 4% and 5% in most genotypes. The RA concentration declined again at 6% sucrose in all genotypes. We concluded that for the extraction of RA from rosemary callus it is preferred to be produced in the dark—this will save energy and will produce more RA than the light treatment. Also it is preferred to use sucrose concentration at 4% for genotypes Rosmarinus officinalis, Pine Scented, and APR; and 3% sucrose for genotype Madeline Hill in the dark condition. While for the light condition, it is preferred to use 5% sucrose with genotypes Majorca, Rosmarinus officinalis, Pine Scented, and Madeline Hill; and 4% sucrose for genotype APR.
(296) Genetic and Molecular Characterization of Putative Ethylene Mutants in Antirrhinum majus
Authors: Heffron Leslie , Jordan Emily , Nugent Jackie , Korban Schuyler
Published: February 2019

Sixteen putative ethylene mutant Antirrhinum majus (snapdragon) lines, derived from 1-aminocyclopropane-1-carboxylic acid (ACC) screening, were crossed in a full diallel that included the wild-type line to determine allelism/complementation groups. Seeds from these crosses were screened on a tissue culture medium containing 5 μM ACC to elucidate the response to exogenous ethylene treatment. Additionally, five of the mutant lines along with an inbred control, from which the mutants were derived, were analyzed using RT-PCR to determine regulation of gene expression in vegetative (roots, shoots, leaves, and sepals) and floral (six stages of flowering, from green bud to post-pollination) tissues using six different ACC synthase (ACS) cDNA clones and two different ethylene receptor (ETR) cDNA clones, all derived from Antirrhinum majus, as probes. Differential regulation of gene expression for ACS and ETR were observed in some tissues and at different stages of floral development.
(171) Blueberry Leaf Inhibits Hepatitis C Virus RNA Replication
Authors: Akamatsu Ena , Kai Takanori , Hirabaru Hideaki , Yukizaki Chizuko , Sakai Miho , Uto Hirofumi , Tsubouchi Hirohito , Kunitake Hisato
Published: February 2019

Blueberry (Vaccinium sp.) fruits contain high concentrations of polyphenols such as anthocyanin. It is well known that polyphenols have antioxidant activity, so it is likely that the fruit has a possible preventative effect against several diseases like cancer. However, only a few reports so far have studied the human health benefits of the leaves. In this study, the antioxidant activity and antiviral effects of blueberry leaves were investigated. The leaves of three groups of blueberry, northern highbush blueberry (NHB), southern highbush blueberry (SHB), and rabbiteye blueberry (REB), were examined. These leaves were harvested in July and extracted with 80% ethanol. Samples were analyzed for antioxidant activity (DPPH radical scavenging activity) and antiviral activity against hepatitis C virus using the replicon cell assay (Lomann et al., 1999). The antioxidant activity showed significant variability between cultivars and species, with REB having about two times the activity of NHB and SHB. Antiviral activity was observed in the extracts of the leaves and the fruit, and the activity of the leaves was higher than that of the fruit. Among the cultivars and species evaluated, the antiviral activity of REB was higher than that of NHB and SHB. In addition, we discovered a positive correlation (r=0.68) between the antioxidant activity and the antiviral activity, using the leaves of hybrid seedlings of REB. Therefore, it is possible to speculate that the antiviral activity bears some relation to the antioxidant activity.
(172) Strawberries Inhibit Cancer Cell Proliferation
Authors: Wang Shiow , Lewers Kimberly , Bowman Linda , Ding Min
Published: February 2019

Representatives of three species of strawberries (Fragaria virginiana, F. chiloensis and F. ×ananassa) were evaluated for antioxidant capacity, scavenging capacity for reactive oxygen species (ROO·, ·OH, 1O2 and O2 .-), and inhibitory effect on proliferation of A549 human lung epithelial cancer cells. Differences among the strawberry genotypes were observed for all three qualities. High antioxidant and scavenging capacities were found in `CFRA 0982', `JP 95-1-1', NC 95-19-1 and RH 30. Lowest antioxidant and scavenging capacities were found in `Allstar'. There was also a relationship between scavenging capacity and the inhibition of cancer cell proliferation. The correlations (R2) between the scavenging capacities for the reactive oxygen species and the inhibition of cancer cell proliferation were 0.8074, 0.8279, 0.7862 and 0.7761 for ROO·, ·OH, 1O2 and O2.-, respectively. These results suggest that antioxidants, specifically their scavenging capacities, may play an important role in the antiproliferative activity of strawberries. This study also identified strawberry germplasm of value in developing cultivars useful for cancer prevention.
(175) Variety- and Cultivation Place-dependent Variations in Capsaicinoid Content of Red Peppers Produced in Cheongyang Area
Authors: Lee Jae-Ho , Cha Hyun-Il , Moon Sang-Mi , Cho Kyoung-Shim , Lee Young-Sang
Published: February 2019

Red pepper, as an ingredient of Kimchi, is an important horticultural crop in Korea, and capsaicinoid content is a major factor determining the pungent quality of red pepper. To clarify the factors affecting capsaicinoid content, 122 red pepper samples of 24 varieties were collected from 21 cultivation sites in Cheongyang area, South Korea, and their nordihydrocapsaicin (NDC), capsaicin (CAP), and dihydrocapsaicin (DHC) contents were evaluated by using an HPLC. The average content of NDC, CAP, and DHC were 4.8, 74.2, and 26.5 mg/100 g, respectively, and its relative composition ratios were slightly affected by variety or cultivation places. In most cultivation places, capsaicinoid contents showed significant dependence upon variety, in that cv. WangJangKum (225.5 mg/100 g) exhibited 6.2-fold higher total capsaicinoid contents when compared to cv. ChonHaTongIl (36.2 mg/100 g). Even the same cultivar (e.g., WangDaeGum) exhibited almost 2-fold variations according to cultivation places, indicating the dependence of capsaicinoid content of red peppers upon the cultivation sites. Analysis of variance revealed significant variety–cultivation place interactions in CAP, DHC, and total capsaicinoid contents, but not in NDC. This data suggests the necessity of more-careful selection of variety and cultivation place corresponding to the expected pungency of harvested red peppers.
Counter-anions Influence Greenhouse Rose (Rosa ×hybrida) Responses to Sodium-based Salinity
Authors: Solis-Perez Alma R. , Cabrera Raul I.
Published: February 2019

Greenhouse rose plants, `Bull's Eye', budded on the rootstocks Rosa manetti and R. × `Natal Briar', were grown in containers filled with a peat-based growing medium. The plants were irrigated with a 0.5× Hoagland solution salinized with a fixed 12-mM Na solution made up of seven ratios of NaCl, Na2SO4, and NaNO3 (100:0, 50:50:0, 0:100:0, 0:50:50, 0:0:100, 50:0:50, and 33:33:33). The results after four flushes of growth and flowering showed higher dry weight productivities in R. manetti plants. Salt composition (i.e., counter-anion ratios) significantly affected the dry weight yield of `Natal Briar' plants, with those irrigated with 100% Na2SO4 and NaNO3 having the highest and lowest values, respectively. While the plants budded on R. manetti did not show significant responses to salt composition, there was a strong tendency for higher dry weight yields in binary salt (anion) compositions. Leachates collected throughout the study showed similar pH (7.5) and electrical conductivities (4.7 dS/m) for all salt treatments. Leachate Cl- concentrations were linearly correlated with Cl- application, whereas leachate Na+ concentrations remained similar among treatments. Plants on R. manetti accumulated less leaf Na+ and Cl- than in R. × `Natal Briar' plants, with lower values observed, in general, in plants irrigated with solutions containing Na2SO4.
Non-irrigation in Fall and Winter Improves Florida Citrus Fruit Quality
Authors: Parsons Larry , Etxeberria Ed
Published: February 2019

Moderate water stress applied to citrus trees can increase fruit °Brix. Florida citrus growers have been required to use less irrigation as competition for water increases. The goal of this study was to see if irrigation could be eliminated in the fall and winter with few negative consequences. Water stress was imposed over a 3-year period on `Hamlin' and `Valencia' oranges (an early and late variety, respectively) by stopping irrigation in late October and restarting it in March. `Hamlin' fruit was harvested after 2 months of stress and `Valencia' fruit was harvested after 4 to 5 months of stress. In most years, °Brix was increased by water stress. Over a 3-year period, `Hamlin' yield was not affected by the water stress, but `Valencia' yield decreased slightly in the 3rd year. The increase in °Brix is beneficial economically, and, over 3 cm of irrigation water per year can be saved.
Detection and Distribution of Viruses Infecting Field-grown Sweetpotato in East Africa
Authors: Miano Douglas , LaBonte Don , Clark Christopher
Published: February 2019

Sweetpotato is an important staple food crop in Sub-Saharan Africa, with production being concentrated in East Africa, particularly around Lake Victoria. Productivity of the crop is greatly constrained by viral diseases. Four main viruses have consistently been detected from various surveys done in the region viz., sweetpotato feathery mottle virus (SPFMV), sweetpotato chlorotic stunt virus (SPCSV), sweetpotato mild mottle virus (Sp.m.MV), and sweetpotato chlorotic fleck virus (SPCFV). The most severe symptoms have been caused by co-infection with SPCSV and SPFMV, resulting in the synergistic sweetpotato virus disease (SPVD). Some local sweetpotato genotypes have been reported to recover from, or have localized distribution of SPVD, suggesting that the disease is not fully systemic. This has led to the suggestion that uninfected cuttings may be obtained from previously infected plants. Experiments were set to determine the possibility of obtaining cuttings long enough for propagation that are free from virus infection. This would form a basis for recommending to the local small-holder farmers of a way to reduce losses due to the disease. Field-grown sweetpotato vines were cut into three pieces (15, 15–30, and >30 cm from the apex) and tested for SPCSV and SPFMV. Nine genotypes were selected from a group of 21 local clones and used for this study. The two viruses were equally present in all the three sections of infected vines, indicating that it is not easy to obtain a virus-free cutting for field propagation from an infected vine. Virus assays in the past has mainly been limited to the use of serological methods. Use of PCR resulted in detection of begomoviruses infecting sweetpotatoes for the first time in the region.
Micropropagation Cultures for Genetic Transformation of Grapevine
Authors: Dutt Manjul , Gray Dennis J. , Li Zhijian T. , Dhekney Sadanand , Van Aman Marilyn M.
Published: February 2019

A major drawback to the use of embryogenic cultures for transformation of grapevine is that their ability to undergo genetic transformation is cultivar-dependent. Also, depending on cultivar, embryogenic cultures are difficult to impossible to maintain over time, reducing their utility for use in genetic transformation. An alternative to the use of embryogenic cultures for transformation of grapevine is the use of micropropagation cultures, which are easier to initiate from a wide range of grapevine cultivars and can be maintained over time without loss of function. Vitis vinifera `Thompson Seedless' was used as a model for genetic transformation using micropropagation cultures. In vitro cultures were initiated from apical meristems of actively growing vines and maintained in C2D medium containing 4 μM of 6-benzylaminopurine (C2D4B). Shoot tips and nodes were collected from proliferating in vitro cultures for transformation studies. A variety of wounding techniques, including nicking, sonication, and fragmenting of meristematic tissues was employed in order to enable Agrobacterium infection. We used a construct containing a bidirectional 35S promoter complex with a marker gene composed of a bifunctional fusion between an enhanced green fluorescent protein (EGFP) gene and a neomycin phosphotransferase (NPTII) gene in one direction and a hybrid lytic peptide gene in the other. Transgenic shoots growing in C2D4B medium containing 200 mg·L-1 each of carbenicillin and cefotaxime and 20 mg·L-1 of kanamycin were selected based on GFP fluorescence. Transgenic shoots were rooted and transferred to a greenhouse. To date, 18 transgenic lines have been generated. Details on the transformation procedure will be discussed.
Characterization of Physiological Resistance to White Mold and Search for Molecular Markers Linked to Resistance via Advanced Backcross QTL Analysis in an Interspecific Cross between Phaseolus coccineus and P. vulgaris
Authors: Haggard J. Erron , Myers James R.
Published: February 2019

White mold, caused by Sclerotinia sclerotiorum (Lib.) de Bary, causes major losses in dry and snap bean (Phaseolus vulgaris) production. With little genetic variation for white mold resistance in common bean, other potential sources for resistance must be investigated. Accessions of scarlet runner bean (P. coccineus) have been shown to have partial resistance exceeding any to be found in common bean. Resistance is quantitative with at least six QTL found in a P. coccineus intraspecific resistant × susceptible cross. Our goal is to transfer high levels of resistance from P. coccineus into commercially acceptable common bean lines. We developed interspecific advanced backcross populations for mapping and transfer of resistance QTL. 111 BC2F5 lines from a cross between OR91G and PI255956 have been tested in straw tests and oxalate tests, as well as in a field trial. The data show that the OR91G × PI255956 population carries a high level of resistance, but because of the quantitative nature of resistance, it may be necessary to intercross individuals to achieve higher levels. SSR, RAPD, and AFLP markers are being tested in the population to construct a linkage map for placement of QTL. QTL identified from each type of test (straw, oxalate, and field) may provide additional information about the genetic architecture of white mold resistance. Three other populations are from advanced backcrosses of the recurrent parents G122, OR91G, and MO162, with PI433251B as the donor parent in each. Analyses and advance of these populations will follow, the results of which should confirm QTL identified in the OR91G × PI255956 population, as well as possible additional resistance QTL from PI433251B.
Bark Splitting and Other Cold Hardiness Effects of Ornamental Herbicides
Authors: Mathers Hannah M. , Bigger Michele M.
Published: February 2019

Many nurseries within Ohio and northeastern, southeastern, and western United States, and Canada have reported severe bark splitting and scald-type problems in 2005. The amount and severity of damage seen in 2005 has been unlike anything seen before. At Ohio State University, samples from across the state started appearing in 2003–04 and increased in incidence in 2005. Growers' reports of exceeding losses of 5% of their inventory or 3000 to 4000 trees per nursery are not uncommon. At an average cost of $125 per tree and with the number of nurseries reporting problems, the stock losses in Ohio have been staggering, in excess of several million dollars. The trees that we have seen problems on in 2005 have been callery pears, yoshino cherry, kwanzan cherry, crab apples, sycamore, serviceberry, hawthorn, mountain ash, black gum, paper bark maple, japanese maples, norway maple `Emerald Queen', red maples, kousa dogwood, magnolia `Elizabeth' and the yellow magnolias such as `Butterflies', `Sawada's Cream', `Yellow Bird', and `Yellow Lantern'. It has long been observed that the actual cause of a bark crack was “preset” by a wound such as the improper removal of a basal sprout, herbicide, leaving of a branch stub, or lack of cold hardiness. Cold and frost may be contributing to the increase in bark splitting across the United States; however, new research results at Ohio State University regarding the effects of DNA preemergent herbicides in the reduction of root hardiness and regrowth potential, sprout removal and other mechanical injuries, and postemergent herbicide application will reveal these are more the causal agents.
Evaluation of Container Media and Cyclic Irrigation on Ilex ×meserveae Growth and Nutrient Concentration in Leachates
Authors: Zinati Gladis
Published: February 2019

Ilex ×meserveae `Blue Princess' plants were grown in a pot-in-pot using container media consisting of pine bark-peat-sand at 90:0:10, 75:15:10, and 60:30:10 by volume. During the summer season, plants were irrigated using a cyclic irrigation regime consisting of two and three irrigation applications and were compared to a traditional irrigation regime with one irrigation application that equaled the total volume applied in the cyclic regime. Nitrate concentrations in leachates were three times lower, whereas ortho-phosphate levels were two times lower in three irrigation application than those in one irrigation application. Increasing the percentage of bark in container media increased nitrate levels and reduced orhto-phosphate levels in leachates. There was no significant difference in growth index among treatments.
Harvest Maturity Affects Response of Beit-alpha Cucumber Fruit to Postharvest Ethylene Exposure
Authors: Hurr Brandon M. , Huber Donald J. , Talcott Stephen T.
Published: February 2019

The present study was conducted to explore the process of watersoaking seen previously in beit alpha-type cucumber fruit treated with ethylene. Fruit were harvested at four levels of maturity: Immature (4 to 8 days after anthesis, DAA), Mature (10 to 14 DAA), Breaker (16 to 20 DAA), and Yellow (35 to 40 DAA). Fruit were then stored at 13 °C in the presence of air (control) or either 10 μL·L-1 ethylene or 1300 μL·L-1 propylene for up to 12 days. The physiological response to ethylene treatment varied with fruit maturity. Immature-stage fruit treated with ethylene for 9 days had mesocarp watersoaking, epidermal sloughing, and lower hue (118°, control 124°), endocarp pH (4.4, control 5.4), and whole fruit firmness (23 N, control 46 N). Mature-stage fruit behaved similarly to Immature-stage fruit, but lacked mesocarp watersoaking. In contrast, after 9 days of ethylene exposure, the Breaker- and Yellow-stage fruit exhibited no watersoaking, accumulated beta-carotene in peel tissue (13.6 μg·g-1 F.W, control 0.35 μg·g-1 F.W.) and had a “melon”-like aroma. Ethylene exposure for all maturities increased respiration rate and decay incidence compared to air-treated fruit. Ethylene evolution was only detectable in fruit with visible decay. Decay incidence in response to ethylene treatment was inversely proportional to maturity at harvest. Watersoaking, exhibited exclusively in Immature fruit, spread inward from the epidermis starting after about 6 days of ethylene treatment. Cells in watersoaked tissue stained negatively for viability with fluorescein diacetate and cells proximal to watersoaked cells stained weakly compared to air-treated controls. Current work is focused on identifying the mechanism of cell death.
Growth of Cypripedium Orchids in Soilless Media Containing Anaerobic Digestion-derived Biosolids
Authors: Compton Michael , Zauche Timothy
Published: February 2019

Lady slipper orchids have great potential as a perennial bedding plant in temperate-zone climates Unfortunately, many gardeners fear these species because of their high cost and perceived difficulties associated with growing plants outdoors. The former factor can be addressed by improving the production of plants at the wholesale level. Growers contest that sphagnum peat and coconut coir are poor organic addenda for these species due to their natural acidity. Anaerobic digestion-derived biosolids (ADB) are not acidic like sphagnum peat or coconut coir, and may be the perfect organic addendum for the culture of ladyslipper orchids. Hence, 3-year-old plants of showy (Cypripedium reginae) and yellow ladyslipper (Cypripedium parviflorum var. pubescens) orchids were grown in soilless potting mixes containing vermiculite and perlite plus various concentrations and combinations of ADB and coconut coir. Plants were grown in the greenhouse at 70 ± 10 °F and received normal light and photoperiod during Summer 2005. Growth, as assessed by the dry weight of dormant stem tissue, of showy ladyslipper potted in media containing ADB was three- to four-times greater than those grown in media containing coconut coir. Growth was similar among yellow ladyslippers grown in media containing ADB or coconut coir due to the fact that these plants had produced all their stem growth for the season before the experiment was initiated. ADB has great potential as an organic addendum to horticultural growing media used for the culture of Cypripedium species. Use of anaerobic digester-derived biosolids in horticultural growing media is a protected intellectual property and available for license through the WiSys Technology Foundation.
Influence of Slow Release Methylene Urea Products on Tomato Yield, Quality, Nutrient Uptake, and Economics
Authors: Sanders Douglas C. , Reyes Luz M.
Published: February 2019

Two formulations of a new methylene urea product on tomato were evaluated. Applications of 150, 200, 250 lb/acre of N in eastern North Carolina and 175 and 250 lb/acre of N in western North Carolina of both liquid and dry formulation of the material were made. The liquid was applied the first 6 weeks of growth and the dry applied at planting. These treatments were compared with 200 lb/acre of N (standard) and 300 lb/acre of N, which were fertigated throughout the season. In eastern North Carolina, all rates of the liquid and high rate of dry formulations produced more yield of larger fruit than the standard. In western North Carolina, all methylene urea sources out-performed the standard. Soil and foliar nitrate was somewhat greater than the standard throughout the season, but, at end of season in the west, only the 250 dry material had more N in the soil. Methylene urea treatments took up more N than the control. All methylene urea except 200 dry produced more dollars per acre than the standard.
Effect of Root Substrates and Nutrient Solution Electrical Conductivity on Tomato Transplant Characteristics
Authors: Sambo Paolo , Sannazzaro Franco , Evans Michael
Published: February 2019

In order to evaluate alternative rooting media as a substitute to sphagnum peat in tomato transplant, fresh rice hulls (2 and 4 mm particle size), perlite, and peat were compared. In the same experiment, four nutrient solutions differing in electrical conductivity [(EC) 2.5, 3.5, 4.5 and 6.0 mS/cm], but not in nutrient content, were used. Seed of tomato (Lycopersium esculentum L.) `Brigade' (ASGROW) were sown in 55 × 35 × 6.5 cm polystyrene transplant trays containing 336 cells (15 mL) and filled with the root substrates. The trays were placed in a glass-glazed greenhouse. Trays were kept under intermittent mist for 6 days and then fertilized twice per week with 2.6 L per tray of solution. A split-plot design with three replications was used with nutrient solution serving as the main plot and root substrates serving as the subplots. During the growing cycle (once a week) and when plants were ready to transplant (16 cm tall, with an average of five to seven true leaves), stem diameter, hypocotyl length, plant height, number of true leaves, fresh shoot weight, and dry shoot weight were measured. Also at transplant, root fresh and dry weight and above- and below-ground biomass were analyzed to determine N, P, K, Ca, Mg, Fe, and Mn content. Plants grown in rice hulls were as marketable as those in peat, but showed a higher content in N, K, and Mn. Increased nutrient solution affected not only dry matter accumulation, but also stem diameter and plant hight, which were greater in plants grown with high EC.
Responsible Plant Growth Recommendations from Greenhouse-grown Bedding Plant Experiments Must Integrate Data from Postharvest Landscape Evaluations
Authors: Arnold Michael , McDonald Garry
Published: February 2019

Multiple experiments conducted over the past 5 years suggest that greenhouse-grown bedding plants, particularly fall-propagated cool-season annuals, may exhibit reductions in vegetative growth and flowering in response to plant growth regulators (PGRs) applied at rates commonly used by growers. Studies using Viola ×wittrockiana Gams as a model system indicated that paclobutrazol applied at production stages and rates reportedly used by growers could result in significant postharvest residual responses that adversely impacted landscape performance. Most of these rates were also included within the recommended ranges on the agricultural chemical labels. Multiple applications to the same plants during production increased the severity of the residual responses and decreased the rates at which residual responses were detectable in landscape plantings. Tests with additional taxa, Brassica oleracea L. var. acephala DC, Calendula officinalis L., Ipomoea carnea Jacq. subsp. fistulosa (Mart. ex Choisy) D. Austin, Lantana urticoides Hayek `L.S. Red', Lupinus texensis Hook., Plumbago auriculata Lam., Salvia greggii Gray, and Verbena canadensis Kunth `Homestead Purple', PGR formulations and at various times of the year indicate that the postharvest landscape responses to PGRs vary among taxa and seasons. These results strongly suggest that in order for researchers to make responsible recommendations on PGR use, studies must include not only greenhouse or nursery production data, but also subsequent testing for residual responses to the PGRs in landscape settings.
Studies with Crisp-textured Blueberries
Authors: Padley Les , Lyrene Paul
Published: February 2019

Over the past two decades, selections that produce crisp-textured blueberries have been noted by breeders. Research was conducted to determine how these selections differ from standard cultivars. Four blueberry clones with crisp texture were compared, using firmness, with 94 advanced selections from the University of Florida blueberry breeding program. The clones, tested for berry firmness with an Instron machine, produced a normal distribution. The crisp clones were at the high end of the distribution, but were not qualitatively different from other firm-fruited selections. Firmness was tested during final stages of berry development to determine if crisp clones softened more slowly than standard cultivars. In both 2003 and 2004, firmness decreased greatly from the white to pink stages of development, with slower loss of firmness thereafter. Crisp and commercial clones were similar in the timing of firmness loss. Berries from six crisp clones and four firm commercial cultivars were subjected to shear cell tests to see if the two groups could be distinguished. Shear cell tests from early and late harvests in the same year showed good agreement. Three of the four crisp clones were much higher in shear force than the other clones tested. A consumer sensory panel was conducted to determine if the average person could distinguish between the berries of crisp and standard cultivars. Ninety-five subjects were given two samples each of crisp and non-crisp blueberries, and asked to designate the one sample they thought the most crisp. Seventy-five subjects chose one of the two crisp clones and 20 chose one of the standard clones. This research indicates that crisp texture in blueberry exists and is recognizable and repeatable, but is difficult to objectively define.
Impact of Hurricanes on Vegetable Crops in South Florida
Authors: Cushman Kent , Ozores-Hampton Monica , Simonne Eric , McAvoy Eugene , Parmenter Darrin , Olczyk Teresa
Published: February 2019

Vegetable producers in south Florida suffered the effects of four major hurricanes during 2004 and two during 2005, causing damage to crops and farms estimated at well over 1 billion dollars each year. Producers were quick to respond by replanting or nursing damaged crops back to health. Green beans and leafy crops appeared least likely to recover or produce acceptable yields after exposure to high winds and driving rains. Young tomato plants up to the second or third string were at times completely stripped of leaf material, yet recovered surprisingly quickly. A replant study showed no benefit in replanting compared to keeping damaged plants in the field. Older tomato plants were marginal in their ability to recover with 10% to 60% reductions in yield for first and second harvests when compared to yields common in the region. As much as 100% of Palm Beach County's 2005 early fall bell pepper planting was destroyed by storms. Other peppers in the region were affected by flooding and subsequent development of root diseases such as phytophthora. Damaged eggplant recovered slowly. Research plantings located in commercial fields and at Research and Education Centers were devastated. In addition to loss of crops, costs to vegetable growers included labor to remove damaged plastic and reset stakes, installation of replacement plastic mulches, replanting, and structural damage to buildings and packing facilities. Some transplant houses and greenhouses for specialty peppers were completely destroyed. Removing plastic coverings before a storm's arrival saved structures and crops. Transplants of all crops were in short supply. Labor was lacking due to reconstruction efforts in New Orleans and the Gulf Coast. Successful and not-so-successful recovery efforts will be shown.
Phenolic Composition and Antioxidant Activity of Minimally Processed Sweetpotatoes
Authors: Padda Malkeet S. , Picha David H.
Published: February 2019

Three different style cuts of minimally processed sweetpotatoes (shredded, French-fry, and sliced) were stored at 0 °C and 5 °C for 4 and 8 days. Total phenolic content, individual phenolic acids, and free radical scavenging activity were determined using Folin-Denis reagent, reversed-phase HPLC, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods, respectively. Total phenolic content in sliced cut sweetpotatoes held at 5 °C was higher than in the shredded cut. Both sliced and French-fry cut sweetpotatoes held at 5 °C had significantly higher antioxidant activity than shredded cut sweetpotatoes. All treatments, except shredded sweetpotatoes held at 0 °C, had significantly higher total phenolic content and antioxidant activity after 4 and 8 days of storage. Minimally processed sweetpotatoes held at 5 °C accumulated more phenolic compounds and had a higher antioxidant activity than sweetpotatoes held at 0 °C. Chlorogenic acid followed by 3,5-dicaffeoylquinic acid were the predominant phenolic acids present in sweetpotatoes. The rate of increase in individual phenolic acid content with storage time was higher at 5 °C than at 0 °C. No tissue browning was observed in any of the cuts after 8 days of storage and the products were considered to be marketable.
Mango Genetic Diversity Analysis and Pedigree Inferences for Florida Cultivars using Microsatellite Markers
Authors: Schnell Raymond , Brown J. Steven , Olano Cecile , Meerow Alan , Campbell Richard , Kuhn David
Published: February 2019

Mangifera indica L. germplasm can be classified by origin with the primary groups being cultivars selected from the centers of diversity for the species, India and Southeast Asia, and those selected in Florida and other tropical and subtropical locations. Accessions have also been classified by horticultural type: cultivars that produce monoembryonic seed vs. cultivars that produce polyembryonic seed. In this study, we used 25 microsatellite loci to estimate genetic diversity among 203 accessions. The 25 microsatellite loci had an average of 6.96 alleles per locus and an average PIC value of 0.552. The total propagation error in the collection, i.e., plants that had been incorrectly labeled or grafted, was estimated to be 6.13%. When compared by origin, the Florida cultivars were more closely related to Indian than to Southeast Asian cultivars. Unbiased gene diversity (Hnb) of 0.600 and 0.582 was found for Indian and Southeast Asian cultivars, respectively, and both were higher than Hnb among Florida cultivars (0.538). When compared by horticultural type, Hnb was higher among the polyembryonic types (0.596) than in the monoembryonic types (0.571). Parentage analysis of the Florida cultivars was accomplished using a multistage process based on introduction dates of cultivars into Florida and selection dates of Florida cultivars. Microsatellite marker evidence suggests that as few as four Indian cultivars, and the land race known as `Turpentine', were involved in the early cultivar selections. Florida may not represent a secondary center of diversity; however, the Florida group is a unique set of cultivars selected under similar conditions offering production stability in a wide range of environments.
Methylation Sensitive Amplification Polymorphism in Date Palms and Their Offshoots
Authors: Fang Jinggui , Chao ChihCheng T.
Published: February 2019

DNA methylation plays an important role in the regulation of gene expression in eukaryotes. The extent and patterns of DNA methylation were assessed in the date palm (Phoenix dactylifera L.) mother plants and their offshoots using the methylation sensitive amplified polymorphism (MSAP) technique. Three types of bands were generated using 12 pairs of primers. Type I bands were present in both EcoR I + Hpa II and EcoR I + Msp I lanes; type II bands were present in EcoR I + Hpa II lanes, but not in EcoR I + Msp I lanes; and type III bands were present in EcoR I + Msp I lanes, but not in EcoR I + Hpa II lanes. The total numbers of these three types of bands were 782, 55, and 34. Among these three types of bands, the polymorphic bands were 34, 10, and 0, respectively. The distribution of polymorphic bands among mother-plants and offshoots could suggest the methylation variation occurred to the mother plants and offshoots. The methylation variation during offshoot growth of date palm was characterized as a process involving mainly of demethylation. Hypomethylation of DNA in offshoots compared with mother plants reflects the marked expression of this molecular feature, which may related to gene expression during development of offshoots. The methylation or demethylation status of specific loci in the mother plants and their offshoots might not relate their lineage but occurred randomly.
Biomass and Total Nonstructural Carbohydrate Partitioning in Relation to Nursery Digging Date, and Subsequent Growth, Development and Fruiting Pattern of Strawberry Runner Plants Propagated in California High-latitude Nurseries
Authors: Kirschbaum Daniel S. , Larson Kirk D. , Weinbaum Steven A. , DeJong Theodore M.
Published: February 2019

The pattern of total nonstructural carbohydrate [starch and soluble sugars (TNC)] accumulation in strawberry (Fragaria ×ananassa Duch.) nursery runner plants, cv. Camarosa, was determined for three growing seasons. A similar study was conducted on `Selva', but for only one year. Growth, development and fruit production patterns of plants transplanted to growth chambers (GC) or fruiting fields were also evaluated. The experiments were carried out on plants propagated in high latitude (41°50' N) nurseries in California (Siskiyou County). Plants were sampled beginning late summer through early autumn and analyzed for dry mass (DM) and TNC. Plants from different digging dates were established in GC or fruit evaluation plots in Irvine, Calif. (33°39'N). Initial TNC concentration in storage tissues at the time of nursery digging increased steadily from the second week of September to the third week of October. Crown and root TNC concentration and content were correlated positively with the accumulation of chilling units (CU = hours ≤7.2 °C) in the nursery. Root TNC concentration consistently increased from 6% to 10% DM in `Camarosa' (a short-day cultivar), and from ∼4% to 14% DM in `Selva' (a day-neutral cultivar) from mid-September to the first week of October. The root TNC content increased ∼2.5 times in `Camarosa' and ∼3.7 times in `Selva' during the same period. Transplant growth, development, and fruiting pattern were affected by digging date. Root TNC concentration and content were more sensitive to CU accumulation than crown TNC concentration and content. Therefore, root sampling appeared to be more appropriate than crown sampling for assessing the carbohydrate status and optimal digging dates of strawberry nursery runner plants early in the fall.
Summer Squash Planting Systems Following a Rye Cover Crop
Authors: Shrefler James W. , Roberts Warren , Webber Charles , Edelson Jonathan , Taylor Merritt
Published: February 2019

Commercial organic vegetable production requires using soil improvement practices and effective weed control measures. Rye (Secale cereale) cover crops are known to suppress annual weeds. Research was begun in 2004 to measure crop yield, annual weed infestation, and weed control requirements for vegetable planting systems that begin with a rye cover crop. Poultry litter was used to supply nutrients and was applied based on a soil test and commercial vegetable recommendations. Rye `Elbon' was seeded 21 Oct. 2004 on beds with 1.8-m centers. Zucchini squash (Cucurbita pepo) `Revenue' was planted the following year using three crop establishment dates, such that transplanting occurred on 6 May, 3 June, and 29 June. Planting system treatments included: conventional tillage (CT), CT and plastic mulch (P), CT with stale seedbed, mow, mow and burn-down, mow and shallow till (ST), ST and burn-down. Following field preparation, squash was transplanted in a single row at the bed center with 0.77-m plant spacing. Drip irrigation was used in all plantings. Emerging weeds were removed by hoeing. Squash was harvested from each planting over approximately 3 weeks and total marketable fruit counts were determined. Marketable yields with P were approximately double those of the CT and ST treatments in the 6 May transplanting. Yields were comparable for CT and ST in the 3 June transplanting, but were significantly lower for the P treatment. There were no significant differences among the treatments that received tillage in the 29 June planting. However, the non-tilled treatments had significantly lower yields compared to tilled treatments.
Within-crown Variation in the Development of Photosynthetic Capacity Is Proportional to Growth Temperature in Temperate Deciduous Trees
Authors: Bauerle William L. , Bowden Joseph D. , Wang Geoff G.
Published: February 2019

This study set out to test the hypothesis that the development in the capacity for the maximal rate of ribulose-1,5-bisphosphate carboxylase/oxygenase (VCmax) and the maximum regeneration rate of ribulose-1,5-bisphosphate (Jmax) per unit mass is proportional to the growth temperature under which the leaf develops and to investigate whether the capacity for photosynthetic acclimation to temperature varies genetically within a species by testing genotypes that originated from diverse thermal environments. Acer rubrum L. (red maple) genotypes were subjected to short-term and long-term temperature alteration to investigate the photosynthetic response. We minimized the variation of within-crown light gradients by growing trees in open grown field conditions and controlled temperature on a crown section basis. Thus, we singled out the temperature acclimation affects on the photosynthetic temperature optimum. In response to temperature acclimation, the genotype from the northern United States downregulated both VCmax and Jmax and had a 5 and 3 °C lower temperature optimum than the genotype native to the southern United States. The activation energy increased and was higher for Jmax than for VCmax in both genotypes. With respect to respiration, both genotypes downregulated about 0.5 μmol·m-2·s-1. Although respiration was lower, the increased energy of activation in response to growth temperature resulted in a decrease in maximum net photosynthetic rate (Amax) under saturating light and CO2. The results illustrate that the photosynthetic capacity adjusted in response to growth temperature but the temperature optimum was different among genotypes.
Variation in Leaf Anatomical Traits of Pecan Cultivars
Authors: Sagaram Madhulika , Lombardini Leonardo , Grauke Larry
Published: February 2019

An assessment of anatomical traits of pecan cultivars (`Pawnee', `Mohawk', and `Starking hardy giant') collected from three locations (Tifton, Ga.; Chetopa, Kans.; and Stillwater, Okla.) was conducted at Texas A&M University. The objective of the study was to provide an understanding of patterns of geographic variation within the natural range for anatomical (stomatal density, stomatal index, and epidermal cell density) traits. Microscopy using acetate casts was used as the means to investigate the patterns of variation in the epidermal characteristics of pecan leaf. `Starking hardy giant' had the greatest number of stomates/cm2 (46,229, 47,807, and 45,990 at Tifton, Chetopa, and Stillwater, respectively) while `Mohawk' had the least (37,397, 36,217, and 35,305). `Pawnee' had the greatest number of epidermal cells/cm2 (251,806, 250,098 and 254,883 at Tifton, Chetopa, and Stillwater, respectively) while `Starking hardy giant' had the least (141,699, 138,405, and 142,155). Differences in stomatal index were observed between the three cultivars at Tifton and Stillwater. No differences in stomatal index were observed between `Pawnee' and `Mohawk' at Chetopa. The study showed that stomatal density as well as epidermal cell density of all the tested cultivars were significantly different (P < 0.05) at a particular location but no differences were observed in a given cultivar grown at different locations.