bluuebunny/crossref_metadata_2025 huggingface dataset:
Nutrition Affects Pre- and Posttransplant Growth of Impatiens and Petunia Plugs
Authors: van Iersel M.W. , Thomas P.A. , Beverly R.B. , Latimer J.G. , Mills H.A.
Published: February 2019

Pre- and posttransplant growth of plug seedlings is affected by the nutrition of the plants. The effects of weekly applications of nutrient solution with different N (8—32 mM) or P and K (0.25—1.0 mM) levels on the growth and nutrient composition of impatiens (Impatiens wallerana Hook. f.) and petunia (Petunia ×hybrida hort. Vilm.-Andr.) plug seedlings were quantified. Impatiens and petunia pretransplant seedling growth was most rapid with a NO3- concentration of 24 or 32 mM (N at 336 and 448 mg·L-1), while P and K had little effect. Increasing the N concentration in the fertilizer also increased shoot tissue N levels of both impatiens and petunia and decreased shoot P level of impatiens and K level of petunia. Posttransplant growth was most rapid in plants that received N at 16 to 32 mM. Decreasing P and K from 1 to 0.25 mM in the pretransplant fertilizer reduced posttransplant growth. Shoot P level of impatiens 15 d after transplanting decreased from 6.9 to 4.8 mg·g-1 as the pretransplant fertilizer N concentration increased from 8 to 32 mM, while N level increased from 18 to 28 mg·g-1 as P and K fertilizer concentrations increased from 0.25 to 1 mM. Using posttransplant growth as a quantitative norm for plug quality, the sufficiency ranges for tissue N level are 28 to 40 mg·g-1 for impatiens and 30 to 43 mg·g-1 for petunia plugs. These results indicate that fertilization programs for high-quality plug production should focus on N nutrition, and that plugs can be grown with greatly reduced levels of P and K.
Comparison of Two Visual Scales for Estimating European Corn Borer Ear Damage in Maize
Authors: Warnock Daniel F. , Davis David W.
Published: February 2019

Some scales combine quantitative and qualitative components that inadvertently may skew damage estimates and eliminate potentially useful germplasm. Two visual evaluation scales to estimate European corn borer feeding damage were compared for their effectiveness in classifying sweet corn germplasm. Both the traditional 1 to 9 scale, combining ear feeding damage and damage location, and the alternative 1 to 5 scale, based solely on ear feeding damage, consistently separated sweet corn genotypes into resistant, marginally resistant, and susceptible classes. Inbred MN 3002, Hybrid MN 3004, `Apache', and `More' were classified as having marginally acceptable resistance levels. Inbred Mn 3003, Inbred W182E, and `Jubilee' were susceptible to European corn borer. Individual genotype rankings varied by scale, but genotype classifications were consistent with regard to the degree of commercial acceptability. The combination of quantitative and qualitative components did not compromise genotypic characterization, as the previously untested hybrid, MN 3004, was placed in the marginally acceptable class by both scales. Plant breeders should carefully evaluate the efficacy of individual visual scales before incorporating them into a selection program.
Somatic Hybridization, an Integral Component of Citrus Cultivar Improvement: I. Scion Improvement
Authors: Grosser J.W. , Jiang J. , Mourao-Fo F.A.A. , Louzada E.S. , Baergen K. , Chandler J.L. , Gmitter F.G.
Published: February 2019

Seedlessness is an important breeding objective of most citrus scion improvement programs, but production of quality seedless triploid citrus via interploid crosses has historically been limited by the low quality of available tetraploid parents. Production of tetraploid hybrid parents from elite diploid scion cultivars via protoplast fusion is now a practical strategy, and numerous hybrids can be produced on a timely basis from a wide range of parents. Such hybrids can be used as pollen parents in interploid crosses to generate improved seedless triploid fresh fruit cultivars. Herein we report the production of 15 such hybrids from 17 different parents, including sweet orange [Citrus sinensis (L.) Osbeck], mandarin/tangerine (C. reticulata Blanco), grapefruit (C. paradisi Macf.), pummelo [C. grandis (L.) Osbeck], tangor (C. reticulata × C. sinensis), and tangelo (C. reticulata × C. paradisi) germplasm. All hybrids were confirmed by cytological and RAPD analyses, and have been budded to selected rootstocks to expedite flowering.
Comparison of Cabbage Seedling Growth in Four Transplant Production Systems
Authors: Frantz Jonathan M. , Welbaum Gregory E. , Shen Zhengxing , Morse Ron
Published: February 2019

“Float-bed” (FB) is a simple hydroponic system used by the tobacco industry for transplant production. “Ebb-and-flood” (EF) is a modified FB system with periodic draining of the bed to limit water availability and control plant growth. Field-bed cabbage (Brassica oleracea L. gp. Capitata) transplant production was compared with FB, EF, and overhead-irrigated plug-tray greenhouse systems. Plants were produced in May and June and transplanted in a field near Blacksburg, Va., in June and July of 1994 and 1995, respectively. Beds for FB and EF production consisted of galvanized metal troughs (3.3 × 0.8 × 0.3 m) lined with a double layer of 0.075-mm-thick black plastic film. In 1994, both EF and FB seedlings were not hardened before transplanting, were severely stressed after transplanting, and had higher seedling mortality compared with plants from other systems. Plug-tray transplants showed the greatest increase in leaf area following transplanting and matured earlier than seedlings produced in other systems. In 1995, EF- and FB-grown cabbage plants were hardened by withholding water before transplanting, and seedlings had greater fresh mass and leaf area than plug-tray or field-bed seedlings 3.5 weeks after transplanting. Less succulent cabbage transplants were grown in EF and FB systems containing 66 mg·L-1 N (40% by nitrate) and 83 mg·L-1 K. Compared with the FB system, the EF system allowed control of water availability, which slowed plant growth, and increased oxygen concentration in the root zone. Both EF and FB systems are suitable for cabbage transplant production.
Using Defoliation to Estimate Yield Losses in Cauliflower: Application in Hail Damage Assessment
Authors: Muro Julio , Irigoyen Ignacio , Lamsfus Carmen
Published: February 2019

Experiments were designed to assess the effects of defoliation and bending back petioles on the head mass of cauliflower (Brassica oleracea L. var. botrytis Alef. subvar. cauliflora, cv. Matra) in the Central Ebro Valley of Spain. Treatments were applied at seven different stages during the growth cycle. Defoliation reduced final head mass, the amount of the reduction increasing with level of defoliation. Bending back the petioles produced a loss in head mass intermediate between that caused by 33% and 66% defoliation. In all four trials, mass loss was highest when defoliation occurred at a head diameter between 20 and 38 mm. Neither defoliation nor bending of the petioles appeared to influence head induction or length of the production cycle. Maximum loss of head mass (85.4% to 64.9%) occurred when cauliflower was totally defoliated at a head diameter of 20—25 mm.
Acetaldehyde, Ethanol, and Carbohydrate Concentrations in Developing Muskmelon Fruit (Cucumis melo L. cv. Andesu) Are Affected by Short-term Shading
Authors: Nishizawa Takashi , Taira Satoshi , Nakanishi Masanori , Ito Masanori , Togashi Masahiro , Motomura Yoshie
Published: February 2019

Acetaldehyde and ethanol production by muskmelon fruit were promoted by short-term shading of the plants for 5 days from 10 to 15 days prior to fruit maturation. Sucrose concentrations in the fruit flesh were reduced by shading, while fructose and glucose concentrations did not differ. Shading also accelerated the development of a “water-soaked” appearance in the flesh.
Phases of Development to Flowering in Opium Poppy (Papaver somniferum L.) under Various Inductive Photoperiods
Authors: Wang Zhongchun , Acock Mary C. , Acock Basil
Published: February 2019

Four phases of development from emergence to anthesis of the opium poppy (Papaver somniferum L.) are recognized based on transfer studies using 9- and 16-hour photoperiods: a photoperiod-insensitive juvenile phase (JP), a photoperiod-sensitive inductive phase (PSP), a photoperiod-sensitive postinductive phase (PSPP), and a photoperiod-insensitive postinductive phase (PIPP). The objective of this experiment was to determine how the durations of the photoperiod-sensitive phases changed when the plants were exposed to different photoperiods. Plants were grown in lamplit growth chambers with a 12-hour thermoperiod of 25 °C day/20 °C night. They were transferred from a noninductive 9-h to an inductive 12-, 14-, or 16-hour photoperiod or vice versa at 1- to 4-day intervals to determine the durations of the four phases. The average number of days to flower by plants grown continuously in a 16-hour photoperiod was 32 days. Days to flower were delayed by 10 days in the 14-hour photoperiod and by 36 days in the 12-hour photoperiod. The durations of the four phases were not equally affected by photoperiod. The first three phases were photoperiod-dependent, the photoperiod effect being nonlinear. The durations of JP, PSP, and PSPP were 3, 5, and 17 days in the 16-hour; 4, 8, and 23 days in the 14-hour; and 7, 14, and 40 days in the 12-hour photoperiod, respectively. The final phase was not sensitive to photoperiod (i.e., PIPP lasted 7 days regardless of photoperiod). Based on these results, we conclude that the so-called juvenile phase cannot be regarded as photoperiod-insensitive. To model the development of opium poppy under field conditions, a knowledge of daylength as early as seedling emergence may be necessary. The number of inductive cycles needed for floral induction and the rate of floral development largely depend on the photoperiod experienced.
Cytological Examination of Scilla peruviana L. during a 20-month Cycle of Growth and Development
Authors: Azizbekova Naza Sh. , Butland Stefanie L. , Ellis Brian E. , Roberts Christia M.
Published: February 2019

The growth cycle of Scilla peruviana L. involved the development of two generations of daughter bulbs enclosed within each mother bulb. Flower initiation of the primary daughter bulb took place in June as the mother bulb apparently entered dormancy. Floral differentiation was complete by late October, by which time the apical meristem of the secondary daughter bulb had developed for 3 months inside the primary daughter bulb. The complete cycle of ontogenesis, from meristem initiation to flowering, occurred without interruption and required 20 months. Small zones of meristematic cells detected at the bases of bulb scales may be the origin of adventitious bulblets in this species. This detailed cytological study enabled the development of an effective commercial forcing program for S. peruviana.
Marigold Cultivars Vary in Susceptibility to Iron Toxicity
Authors: Albano Joseph P. , Miller William B.
Published: February 2019

The susceptibility of seven African marigold (Tagetes erecta L.) cultivars to iron toxicity was assessed. Plants were grown in a greenhouse in a soilless medium and Fe-DTPA was incorporated into the nutrient solution at either 0.018 mmol·L-1 (low) or 0.36 mmol·L-1 (high). Symptoms of Fe toxicity (bronze speckle disorder in marigold characterized by chlorotic and necrotic speckling and downward leaf cupping and curling) developed only in the high-Fe treatment. The concentration of Fe in leaves in the high-Fe treatment was 5.6 and 1.7 times as great as in the low-Fe treatment for `Orange Jubilee' and `Discovery Orange', respectively. Based upon the percentage of plants affected and leaf symptom severity, relative cultivar susceptibility to Fe toxicity was Orange Jubilee > First Lady > Orange Lady > Yellow Galore > Gold Lady > Marvel Gold > Discovery Orange. Chemical names used: ferric diethylenetriaminepentaacetic acid, disodium salt dihydrate (Fe-DTPA).
Three-dimensional Models Represent Seed Moisture Content as a Function of Relative Humidity and Temperature
Authors: Fang Jian , Moore Frank , Roos Eric , Walters Christina
Published: February 2019

Seed moisture content (MC) has been considered the most important factor controlling physiological reactions in seeds, and MC changes with relative humidity (RH) and temperature (T). This relationship is revealed by studying the interaction of RH and T at equilibrium. Cucumber (Cucumis sativus L.), lettuce (Lactuca sativa L.), maize (Zea mays L.), onion (Allium cepa L.), pea (Pisum sativum L.), and watermelon (Citrullus lanatus M. & N.) seeds were equilibrated over sulfuric acid (1% RH) and various saturated salt solutions (5.5% to 93% RH) at temperatures from 5 to 50 °C. Best-fit subset models were selected from the complete third-order model MC = β0 + β1*RH + β2*T + β3*RH2 + β4*T2 + β5*RH*T + β6*RH3 + β7*T3 + β8*RH*T2 + β9*RH2*T, using Mallows' minimum Cp as the selection criterion. All six best subset models (R2, 0.98 to 0.99) had the same functional form, MC = β0 + β1*RH + β2*T + β3*RH2 + β5*RH*T + β6*RH3 + β9*RH2*T. Coefficients had essentially the same respective values among all species except onion and pea, for which some coefficients were statistically different from those of the other species (P ≤ 0.05). All models indicated that seed MC increased as RH increased and decreased as T increased; but RH had the greater influence. The inverse relationship between seed MC and T, although slight, was evident in the response surfaces. The interaction effect of RH and T on MC was significant at P ≤0.001. These results suggest that orthodox seed species respond similarly to T and RH. This in turn suggests that a common model could be developed and used for optimizing seed storage environments.
Auxins Affect Posttransplant Shoot and Root Growth of Vinca Seedlings
Authors: van Iersel Marc
Published: February 2019

Transplanting often causes root damage, and rapid root growth following transplanting may help to minimize the effects of transplant shock. The objective of this study was to determine the effects of NAA and IAA on posttransplant growth of vinca (Catharanthus roseus L.). Bare-root seedlings were germinated in a peat-based growing mix and transplanted into diatomaceous earth 10 days after seeding. Immediately after transplanting, seedlings were drenched with several concentrations of IAA or NAA (62.5 mL/plant). Both auxins increased posttransplant root and shoot growth, but the response was dose-dependent. The maximum growth occurred at concentrations of 10 mg·L-1 (IAA) or 0.1 mg·L-1 (NAA). The growth-stimulating effect of these auxins decreased at higher rates and NAA was highly toxic at 100 mg·L-1, killing most of the plants. Unlike the growth of bare-root seedlings, plug seedling growth was not stimulated by drenching with NAA solutions. These results show that auxins have the ability to stimulate posttransplant growth of vinca, but their effects may depend on the application method, rate, and timing, and transplanting method. Chemical names used: 1-naphthaleneacetic acid (NAA); 1-indole-3-acetic acid (IAA).
Low-temperature Storage Elicits Ethylene Production in Nonclimacteric Lychee (Litchi chinensis Sonn.) Fruit
Authors: Chan Yee Kwan , Yang Yung Hua , Li Ning
Published: February 2019

Lychee (Litchi chinensis Sonn.) fruit were harvested at green, pink, and red developmental stages. The fruit of each group were used to determine developmentally and environmentally (chilling) regulated ethylene production. The rate of ethylene production in the fruit was green > pink > red. Storage at either 4 or 10 °C increased C2H4 production as much as 8.6-fold compared with control fruit stored at 25 °C. The green fruit were most responsive to chilling in terms of ethylene production.
Rate and Synchrony of Seed Germination Influence Growth of Hydroponic Lettuce
Authors: Korkmaz Ahmet , Pill Wallace G. , Cobb Bruce B.
Published: February 2019

The effect of seed germination rate, or of seedling emergence rate, was studied in relation to subsequent plant growth of `Cortina' lettuce (Lactuca sativa L.). Seedling growth response to selection by time of germination was assessed by imbibing seeds at 5 °C to increase the time range for germination. Germinated seeds were removed daily and transferred to “slants” (germination paper held at 20° from vertical) at 15 °C. Five days after each transfer, root and hypocotyl lengths were measured. As days required for germination increased, root lengths decreased and hypocotyl lengths increased, resulting in no change in total seedling length. The relation between rate of seedling emergence from raw or pelleted seeds of the same lot and shoot fresh weight was examined using commercially practiced hydroponic techniques. Shoot fresh weight at 10 and 21 days after planting was related inversely and linearly to the day of emergence for both seed treatments. In the same study, the coefficient of variation of shoot fresh weight was positively related to time of seedling emergence only at 10 days. Germinated seeds were selected after 1 and 2 days of imbibition; subsequent seedling emergence rate and shoot fresh weight at 25 days were recorded. First-day germinated seeds had faster and more synchronous emergence, and produced heavier and more uniform shoots. Discarding slow-to-germinate seeds should enhance seedling emergence and growth.
Seasonal Reproductive and Vegetative Growth Patterns and Resource Allocation during Cactus Pear Fruit Growth
Authors: Inglese P. , Barbera G. , La Mantia T.
Published: February 2019

Flowers and stems (cladodes) of cactus pear [Opuntia ficus-indica (L.) Mill.] appear simultaneously in spring, and a second vegetative and reproductive flush can be obtained in early summer by completely removing flowers and cladodes of the spring flush at bloom time. The seasonal growth patterns of cactus pear fruits and cladodes were examined in terms of dry-weight accumulation and cladode extension (surface area) to determine if cladodes are competitive sinks during fruit development. Thermal time was calculated in terms of growing degree hours (GDH) accumulated from bud burst until fruit harvest. Fruits of the spring flush had a 25% lower dry weight and a shorter development period than the summer flush fruits, and, particularly, a shorter duration and a lower growth rate at the stage when most of the core development occurred. The duration of the fruit development period was better explained in terms of thermal rather than chronological time. The number of days required to reach commercial harvest maturity changed with the time of bud burst, but the thermal time (40 × 103 GDH) did not. Newly developing cladodes may become competitive sinks for resource allocation during most of fruit growth, as indicated by the cladode's higher absolute growth rate, and the fruit had the highest growth rate during the final swell of the core, corresponding to a consistent reduction in cladode growth rate. Cladode surface area extension in the first flush ceased at the time of summer fruit harvest (20 Aug.), while cladodes continued to increase in dry weight and thickness until the end of the growing season (November), and, eventually, during winter. The growth of fruit and cladodes of the summer flush occurred simultaneously over the course of the season; the cladodes had a similar surface area and a lower (25%) dry-weight accumulation and thickness than did first flush cladodes. The proportion of annual aboveground dry matter allocated to the fruits was 35% for the spring flush and 46% for the summer flush, being similar to harvest increment values reported for other fruit crops, such as peach [Prunus persica (L.) Batsch.]. Summer cladode pruning and fruit thinning should be accomplished early in the season to avoid resource-limited growth conditions that could reduce fruit and cladode growth potential.
Low Temperature Tolerance of Zoysiagrasses
Authors: Dunn J.H. , Bughrara S.S. , Warmund M.R. , Fresenburg B.F.
Published: February 2019

Rhizomes of zoysiagrass (Zoysia spp.) were subjected to controlled freezing tests in Jan. and Mar. 1993 and 1994 to determine their low-temperature tolerance. In 1994, `Belair', `Korean `Common', `Meyer', and `TGS-W10' rhizomes survived temperatures as low as -18 °C, while rhizomes of `Sunburst' survived -14 °C. `Cavalier', `Crowne', `Palisades', `Emerald', and `El Toro' were killed at -10 °C or warmer temperatures. Entries surviving exposure to -14 to -18 °C in 1994 controlled freezing tests received post-winter survival ratings in the field of 6.7 to 8.7 (9 = 100% green). Entries killed at higher freezing test temperatures were slower to recover after winter in the field, with ratings of 2.0 to 3.0. Shoot number produced after freezing was a better measurement for assessing low temperature tolerance than was shoot mass. Controlled freezing tests, using regrowth as a measure of hardiness, appear to be useful for identifying low temperature tolerance of zoysiagrasses in the early years of a field study.
Factors Influencing Water Split of Pecan Fruit
Authors: Wood Bruce W. , Reilly Charles C.
Published: February 2019

Water stage fruit split (WS) is an erratic and complex problem often causing major crop losses to susceptible pecan [Carya illinoinensis (Wangenh.) K. Koch] cultivars. This study identified two episodes of WS for `Wichita' pecan—a highly susceptible cultivar. The previously recognized precipitation-induced fruit splitting is the major episode; however, a previously unrecognized precipitation-independent, minor episode can also occured before the major episode. This minor episode was associated with the low solar irradiance and high relative humidity—conditions commonly associated with August rains. The crop characteristics of affected trees also influenced WS in that WS increased as crop load per tree increased. Fruits were also more likely to exhibit WS if located within the lower tree canopy. Treatment of foliage with an antitranspirant immediately before split-inducing conditions increased WS. Maintenance of moist soils for ≈2 weeks before WS-inducing conditions substantially reduced WS-related crop losses. These findings help to explain the erratic nature of WS and indicate that maintenance of trees in a well-watered state for ≈2 weeks before the initiation of shell hardening may substantially reduce WS-related crop losses in certain years.
Gooseberry Mite Infestation Decreases the Cold Hardiness of Dormant Black Currant Flower Buds
Authors: Carter John , Hummer Kim E.
Published: February 2019

Black currant (Ribes nigrum L.) cultivars with heavy, light, and no gooseberry mite (Cecidophyopsis grossulariae Collinge) infestation levels (MIL) were tested for cold hardiness by visually determining the bud injury rating (BIR) after laboratory freezing in Jan. 1998. Lightly mite-infested cvs. Blackdown and Risager, usually thought of as less cold hardy than Nordic cultivars, survived -35 °C, while mite-infested buds of the Finnish cv. Brödtorp were injured at -35 °C. Heavily mite-infested buds of the Swedish R. nigrum L. cv. StorKlas from Corvallis, Ore., were injured at -20 °C while lightly infested buds were injured to -25 °C. Noninfested `StorKlas' buds from Pennsylvania and British Columbia survived laboratory freezing to -35 °C. Heavy mite infestation lowered the bud cold hardiness of `Brödtorp' and `StorKlas' by 10 °C, as estimated by a modified Spearman-Karber T50, relative to the hardiness of lightly mite-infested buds of these cultivars. Heavily mite-infested buds contained unusual tissues forming what appeared to be spherical blisters or eruptions, ≈100 μ in diameter. Other tissues in the region of heavy mite infestation appeared to be more turgid than their noninfested counterparts. Abiotic and biotic stresses can have a combined impact on field-grown black currants.
Chitosan Treatment Affects Plant Growth and Flower Quality in Eustoma grandiflorum
Authors: Ohta K. , Taniguchi A. , Konishi N. , Hosoki T.
Published: February 2019

The effects of chitosan treatment on plant growth and flower quality of Eustoma grandiflorum (Raf.) Shinn. were investigated. The application of a soil mix of chitosan (1%, w/w) at sowing time remarkably enhanced growth, whereas coating seed with 0.1% chitosan in lactate was ineffective. Plants grown in the chitosan-treated soil flowered 15 days earlier than did control plants, and the number and weight of cut flowers produced were greater than for control plants or plants from chitosan-treated seed. Chemical name used: poly-(1→4)-β-D-glucoseamine (chitosan).
Rate and Time of Boron Application Increase Almond Productivity and Tissue Boron Concentration
Authors: Nyomora Agnes M.S. , Brown Patrick H. , Krueger Bill
Published: February 2019

Previous studies with tree species have demonstrated that foliar boron (B) promotes flowering, fruit set, and yield. However, for most species the optimum time for foliar B application has not been determined. This investigation was undertaken to study the effects of time and rate of B application on almond [Prunus dulcis (Mill D.A. Webb)] tissue B concentration, fruit set, and yield. Solubor (Na2B8O13.4H2O), a commercial product containing 20.5% B, was applied with a handgun sprayer either in September (3 weeks postharvest), December (dormancy), or February (budbreak) at rates of 0, 0.8, and 1.7 kg·ha-1 B to almond cv. Butte at one site (Parlier, Fresno County, Calif.), and of 0, 0.8, 1.25, 1.7, and 2.1 kg·ha-1 B on the same cultivar in August, September, or February at a second site (Orland, Glenn County, Calif.) using Borosol, a polyboronated commercial product containing 10% B. At site 1, September application was more effective in increasing tissue B concentration, fruit set, and yield than were December or February applications. The optimal rate was 0.8 to 1.7 kg·ha-1 B when applied in September. At site 2, application in 1996 and 1997 increased tissue B concentration almost linearly, especially when applied in August and February. Application at the highest rate (2.1 kg·ha-1 B) in September produced the greatest final fruit set and yield in 1996. February applications increased initial fruit set at both sites but were less effective than September applications in increasing yield. Application of B did not affect any yield variable in 1997. These results suggest that B should be applied immediately postharvest (September) for optimal effect on tissue B concentration, fruit set, and yield in almond.
Relationships of Nitrogenous Compounds in Petiole Sap of Tomato to Nitrogen Fertilization and the Value of these Compounds as a Predictor of Yield
Authors: Andersen Peter C. , Rhoads Fred M. , Olson Steven M. , Brodbeck Brent V.
Published: February 2019

`Colonial' tomato (Lycopersicon esculentum Mill.) plants were grown on raised beds with black polyethylene mulch, drip irrigation, and preplant-N rates of 0, 67, 134, 202, or 269 kg·ha-1. Petiole sap was collected 7 and 13 weeks after transplanting. Concentrations of NO3-N, free amino acids, total amino acids, and total-N (the sum of NO3-N and amino acid-N) were examined as functions of the rate of N fertilization. Also, each of these compounds was used as an independent variable as a predictor of fruit yield. Seven weeks after planting, the concentrations of NO3-N and 15 of 18 of the free amino acids were correlated with the rate of N fertilization, but concentrations of bound or total amino acids were not. The amount of NO3-N accounted for 37% of the total-N in the 0 kg·ha-1 treatment, and up to 83% in the 202 kg·ha-1 treatment. NO3-N was highly correlated with total-N for both nonhydrolyzed and hydrolyzed sap (R2 = 0.98). Thirteen weeks after transplanting, neither the concentration of NO3-N nor that of amino acids, other than asparagine, glutamine, and proline, were significantly related to the rate of N fertilization. On both dates, concentrations of glutamine plus glutamic acid were correlated with rate of N fertilization whether expressed as absolute values or as percentage values. N fertilization rate and the concentration of NO3-N or total-N were related to total fruit yield (R2 = 0.69 to 0.74), and marketable fruit yield (R2 = 0.78 to 0.82). N-fertilization rate and petiole sap concentrations of NO3-N or total-N were also correlated with the N contained in total or marketable yield. Petiole sap variables measured 13 weeks after transplanting were not significantly correlated with fruit yield or the quantity of N contained in the fruit. Free, bound, or total amino acids in petiole sap were not as well correlated with fruit yield parameters as were N-fertilization rate, NO3-N, or total-N in petiole sap.
Wheat Gluten Meal Inhibits Germination and Growth of Broadleaf and Grassy Weeds
Authors: Gough R.E. , Carlstrom R.
Published: February 2019

The herbicidal activity of wheat gluten meal (WGM) was evaluated on 17 species of monocotyledons and dicotyledons. Treatments included WGM at 0, 1, 2, 3, 4, 6, and 9 g·dm-2. Germination, shoot and root lengths, and root numbers were recorded. Treatments reduced germination and root extension in nearly all species. Leafy spurge (Euphorbia esula L.), redroot pigweed (Amaranthus retroflexus L.), shepherd's purse [Capsella bursa-pastoris (L.) Medik.], henbit (Lamium amplexicaule L.), quackgrass [Agropyron repens (L.) Beauv.], annual bluegrass (Poa annua L.), Canada thistle [Cirsium arvense (L.) Scop.], orchardgrass (Dactylis glomerata L.), purslane (Portulaca oleracea L.), annual ryegrass (Lolium multiflorum Lam.), and snap bean (Phaseolus vulgaris L.) were particularly sensitive. Germination of curly dock (Rumex crispus L.) and common lambsquarters (Chenopodium album L.) was suppressed at the higher rates. Germination of black medic (Medicago lupulina L.), spotted knapweed (Centaurea maculosa Lam.), mustard (Brassica sp.), and corn (Zea mays L.) were not substantially affected at any rate. Shoot growth of all species was inhibited at rates >2 g·dm-2, and at the highest rates no shoots developed. In nine species, shoot extension was stimulated at 1 g·dm-2 WGM. The herbicidal activity of WGM was not due to a “mulching” effect, since growth characteristics were also altered in bean seeds barely covered by the treatments.
Digital Video Technology as an Aid for Quantifying Root Rot
Authors: Pasian C.C. , Ramirez F. Varela , Nameth S.
Published: February 2019

Evaluation of disease severity in root systems is usually subjective, based on observation and categorization into an arbitrary scale of several categories. Results obtained using this approach can vary according to the observer's experience. A new, simple method for evaluating and quantifying the root severity index (RSI) was developed. This method consists of surrounding the root pan with a transparent film and tracing all roots with a marker. On a second transparency, only healthy roots are traced. Lengths of both healthy and diseased roots are measured with a root length/area meter (Dias II). The method of peripheral root-ball root tracings was evaluated with poinsettias infected with Pythium ultimum (Trow.). Results indicated that it was as effective as the traditional method of determining RSI for total and peripheral roots.
Nondestructive Analysis of Sweet Corn Maturity Using NMR
Authors: Ruan R. Roger , Chen Paul L. , Almaer Simon
Published: February 2019

This paper describes the relationship between the maturity stages and nuclear magnetic resonance (NMR) characteristics of sweet corn (Zea mays L.). The NMR parameter T2, which is the spin–spin relaxation time constant, and two conventional maturity parameters, moisture content and alcohol insoluble solids (AIS), of sweet corn samples during maturation, were determined and correlated with reference maturity indices, namely, heat units and sensory maturity scores. The relationships between T2 and the heat unit and sensory maturity score of the samples were linear, suggesting that T2 can be used to establish mathematical models for the prediction of sweet corn maturity to determine harvest time. The major advantages of using NMR are the nondestructive nature, the speed, and the simplicity of the method.
002 Effects of Hungavit® Liquid Bio-fertilizer on Leaf Chlorophyll Content, Disease Incidence, and Yield of Tomato, Pepper, and Potato
Authors: Soltani Nader , Lazarovits George , Brown Arran
Published: February 2019

Hungavit® products contain extracts of earthworm castings and are marketed by BioLife Ltd. as liquid Bio-leaf fertilizer and plant conditioner. Three experimental plots were set up on the AAFC-SCPFRC research farm to evaluate Hungavit®UR, Hungavit®P, and a preparation containing the equivalent amount of N, P, K fertilizer. In Spring 1998, four replicate plots/treatment of tomato, pepper, and potato were set up in a randomized block design. Each plot received the following treatments: untreated control, Hungavit®UR for tomato and pepper or Hungavit®P for potato, and the fertilizer equivalent of Hungavit®UR or P without the organic components. Tomato and pepper plants were treated three times by foliar application at the rate of 5 L/ha using 300 L of water/ha carrier. Leaf chlorophyll contents were measured at 2, 4, and 6 weeks after initial treatment application. Early and total yield were determined. Tomato fruit were evaluated for symptoms of bacterial spot, early blight, anthracnose, and blossom end rot; pepper fruit for bacterial spot; and potato tubers for potato scab. Both Hungavit® and its equivalent fertilizer application increased the chlorophyll readings significantly in at least one measurement for tomato, pepper, and potato plants. Although there were 40% to 55% fewer diseased tomato and pepper fruit in fertilizer and Hungavit® UR treatments, this was not statistically significant from the control treatments. Fertilizer treatment also reduced scab incidence in tubers by 50%, but the overall scab level was very low even in untreated plots. Hungavit® and its fertilizer equivalent had no significant effect on the early or total yield of tomato, pepper, or potato plants.
004 Root Application of Potassium Silicate Reduce Feeding Damage to Sargent Crabapple Leaf Tissues by Adult Japanese Beetles
Authors: Shirazi A.M. , Miller F.D.
Published: February 2019

Research on silicon nutrition has shown an increase in plant disease resistance to powdery mildew and pythium in some species, such as roses and cucumbers. However, the role of silicon for protecting plants from other stresses e.g., heat, drought, insects, etc., are not known. Two-year-old Sargent Crabapple Malus sargentii seedlings were subjected to 4 continuous days of 100 ml root application of potassium silicate at the rate of 0, 100, 200, and 400 ppm in Aug. 1998. After 3 days post-treatment, three detached leaves were placed in each of three petri dishes along with one adult female Japanese beetle (n = 3/concentrations) for 7 days. Potassium silicate at 100 ppm concentration significantly reduced percent leaf tissue eaten by adult Japanese beetles. There was not any statistical difference between control, 200, and 400 ppm application. The ion leakage of stem tissues of 100 and 200 ppm-treated plants were significantly lower than the control and 400 ppm. These lower ion leakage effects were also observed with red-osier dogwood stem tissues at 100 ppm. In a companion study fall webworm larvae were also exposed to the same above concentrations and treatments. There was not a significant effect of potassium pilicate on percent leaf tissue eaten by fall webworm larvae, suggesting that there may be differences between major groups of leaf-feeding insects. Leaf and root tissue analysis for Ca, K, Mg, Na, and Si will be reported.
005 Investigations Into the Cause of Gold Flecking on the Surface of Ripe Tomato Fruit
Authors: Davis Jeanine M.
Published: February 2019

In recent years there has been an increase in the incidence of “gold flecking,” which develops on the surface of ripe tomato fruit. Gold flecking looks like a light sprinkling of gold on the skin of the fruit. There are no lesions and the interior of the fruit is not affected. Usually, gold flecking is barely noticeable. In 1998, however, gold flecking was severe enough in some cases to cause economic losses. It has been suggested that gold flecking is due to use of the insecticide Asana or it may be a genetic disorder. The objective here was to determine if gold flecking is caused by Asana and/or is cultivar-dependent. Treatments consisted of three cultivars (Mountain Fresh, Celebrity, and Mountain Pride) and four insecticides (Asana XL, Karate 1 EC, Thiodan 50 WP, and a water control). There were two plantings. Only red fruit was harvested. For both plantings, there was more gold flecking in the control than any of the insecticide treatments. There were no differences among the insecticides. For the early planting, `Mountain Fresh' had more gold fleck than the other cultivars. In the late planting, there were no differences between cultivars. This study demonstrates that Asana was not responsible for gold flecking and actually reduced it compared to the control. These results also suggest that insects may play a role in gold flecking.
011 Reflective Mulches and Yellow Sticky Tape Control Whiteflies in Greenhouse Poinsettia (Euphorbia pulcherrima)
Authors: Rice Robert P. , Baird Shelly , Gatlin Linzy
Published: February 2019

Greenhouse Whitefly (Trialeurodes vaporariorum) and Silverleaf Whitefly (Bemisia argentifolii) are the most serious insect pests of poinsettia. Most growers rely on the use of foliar insecticide applications before bract coloring and an application of a single soil application of imidicloprid (Marathon) subsequently. This research was undertaken to investigate the use of reflective mulches or bench covers, which have been shown to be effective in outdoor applications for control of whitefly in the greenhouse. In an early trial, silver painted pot spacers and silver polyethylene mulch were placed between pots and both nymphs on leaves and adults caught on yellow sticky cards were monitored. Nymph populations were reduced by ≈35% and adults caught on sticky cards increased by ≈40% when compared with the control. In a subsequent trial, reflective bench covers were combined with the use of yellow sticky tape placed above the canopy of the crop and compared with sticky tape alone, reflective mulch alone, and no treatment. The combination of sticky tape and reflective mulch significantly reduced whitefly populations after 6 weeks and performed better than either of the other treatments alone.
024 IPM Practices Reduce Pesticide Levels in Runoff Water at a Container Nursery
Authors: Briggs Jeanne , Whitwell Ted , Riley Melissa B. , Fernandez Tom
Published: February 2019

This study investigated effects of two pesticide applications regimes, Integrated Pest Management (IPM), in which pesticides were only applied to affected plants when damage was noticed, and Traditional, in which pesticide applications were made on a scheduled and preventative basis, on growth and health of container grown plants. Field research was conducted at a large wholesale nursery in the piedmont region of South Carolina. An isolated portion of the nursery contained eight beds that housed 25 species of woody and herbaceous ornamentals. IPM beds were subjected to weekly in-depth scouting of indicator species, and all other plant materials in both treatments were visually checked for problems on a weekly basis. The study began in June 1998 with weekly scouting ending in late October. Monthly scouting continued through the winter of 1999. Runoff water was collected from the treatments after all pesticide applications and analyzed to determine concentrations of chemicals. Plant health was rated at study's end to allow comparison between treatments. Amounts of isoxaben detected in runoff water were 7.9 g for the traditional treatment and 0.9 g for the IPM treatment. Amounts of thiophanate-methyl and chlorothalinol were similarly lower for the IPM treatment. Preliminary results indicate that plant growth was similar for both treatments.
028 Selecting Sweetpotato Genotypes Tolerant to Chilling Stress
Authors: Izekor Ehiorobo , Garner J.O. , Matta F.B.
Published: February 2019

A procedure to determined selection of sweetpotato (Ipomoea batatas L. Lam.) genotypes tolerant to chilling injury was initiated by crossing two resistance lines and two susceptible lines. Experimental design on the F1 progeny was a completely randomized design (CRD) with two groups, tolerant and sensitive genotypes, and 90 lines in each group. Four plants per lines were selected and each plant represented a replication. The rating of plants according to the degree of chilling injury was recorded at 36 h after chilling temperature of 5 °C with 85% relative humidity. Significance of the analysis was based on the number of plants tolerant to chilling injury from both the resistant and the sensitive groups. Results from the statistical analysis based on visual rating of the F1 progeny plants for 36 h, indicated that higher populations of resistant plants could be produced when two resistant lines were crossed in a control pollination process. Evaluations to be continued are chlorophyll fluorescence, leakage of cell content, structural changes of the cell, and peroxidase content, before and after chilling stress. These assays will be used to further determine the similarities among the chilling-tolerant genotypes. Findings will aid in elucidating mechanism of chilling injury in fruit and vegetables.
031 Rate of Natural Outcrossing in Cucumber Isolation Blocks
Authors: Wehner Todd C.
Published: February 2019

Cucumber (Cucumis sativus L.) populations often are intercrossed after each selection cycle using bees in isolation blocks. Previous research showed the rate of natural outcrossing in monoecious cucumber inbreds was 36%. The objective of this experiment was to determine whether the rate of natural outcrossing could be increased using hormones, plot size, and node of fruit for seed harvest. The experiment was run with 2 years (1997, 1998), two hormones (treated, none), two plot sizes (hills, small plots), two nodes of harvest (2, 8), and four replications. Each treatment combination consisted of four plots or hills planted in 1.5-m rows in one isolation block. Plots or hills were planted to white-spined `Sumter', and were surrounded by rows of black-spined `Wis. SMR 18'. Treatment combinations receiving hormones were sprayed at the cotyledon stage and 1 week later. Plots or hills received ethrel to make them gynoecious, and surrounding rows received silver nitrate to make them androecious. Unsprayed isolation blocks remained monoecious. At maturity, fruit were harvested from nodes 2 or 8 from the white-spined plants in each isolation block. Node of harvest had no effect on outcrossing rate. However, hormones and plot size had a significant effect. Sprayed plots, sprayed hills, and unsprayed hills had high outcrossing rates relative to unsprayed plots. Therefore, if families are to be intercrossed in isolation blocks, they should be sprayed with hormones for maximum outcrossing among families.
044 Selection for Floret Glucoraphanin Concentration Among Inbred Broccoli
Authors: Farnham Mark W. , Fahey Jed W. , Stephenson Katherine K.
Published: February 2019

Broccoli (Brassica oleracea L. Italica Group) is a rich source of the aliphatic glucosinolate glucoraphanin. The glucoraphanin breakdown product, sulforaphane, has been shown to induce Phase II detoxication enzymes (e.g., Quinone Reductase) and has attracted attention as a potential chemoprotector against cancer. The objectives of this research were to evaluate the concentration of glucoraphanin in an array of diverse broccoli inbreds (doubled-haploids) largely derived from commercial germplasm and to determine if expression of glucoraphanin level in this initial evaluation is correlated with expression in a subsequent environment. In 1996, individual florets from single broccoli heads were sampled from 75 inbred lines grown in the field at Charleston, S.C., and glucoraphanin concentration was assayed. In this test, concentrations ranged from 0.04 to 2.94 μmol glucoraphanin per g fresh weight of florets and the mean concentration was 0.86. In 1997, a subset of 22 inbreds analyzed the first year were grown again in a replicated field trial. This inbred subset was made up of lines with diverse pedigrees and with high, low, or intermediate glucoraphanin concentrations. In this second year, glucoraphanin concentration had a range from 0.24 to 2.99 μmol per g fresh weight of florets and a mean of 1.37. Correlation of entry mean glucoraphanin concentration in 1997 with that in 1996 was positive (r = 0.79) and highly significant (P < 0.001) indicating that floret glucoraphanin concentration was relatively consistent between years. These observations provide evidence that floret glucoraphanin concentration has a significant genetic component.
045 Carotenoid Antioxidant Levels in Spinach
Authors: Kirkpatrick J.A. , Murphy J.B. , Morelock T.E.
Published: February 2019

Interest in the health benefits of vegetables prompted an investigation of the levels of carotenoids in commercial varieties and UA breeding lines of spinach. Plant carotenoids perform a critical function as antioxidants, providing protection against a variety of reactive oxygen species generated primarily during photosynthesis. When ingested by humans, these compounds maintain their antioxidant activities and are receiving considerable attention in relation to multiple health benefits, including cancer prevention. While the best-known and most-studied carotenoid is beta-carotene, other carotenoids are now receiving attention due to their higher antioxidant activity compared to beta-carotene. Most dark-green leafy vegetables, such as spinach and kale, are relatively high in carotenoids, especially lutein. In this study, significant differences in average content of both lutein and beta-carotene were found between genetic lines of spinach. Some lines exhibited considerable variation between plants, while others were highly uniform. There was a very high correlation (r2 = 0.96) between lutein content and betacarotene content. The significant difference between spinach lines suggests that improvement of general carotenoid antioxidants and lutein could be obtained through a breeding program.
049 Development of Molecular Markers Linked to High Pigment (hp) and Dark Green (dg) Loci in Tomato
Authors: Zhang Yiping , Stommel John R.
Published: February 2019

The carotenoids have an important influence on tomato fruit quality and enhance the fruit contribution to human nutrition. Expression of the high pigment (hp) locus in tomato results in increased total carotenoids and increased efficiency of utilization of the polyenes. A similar mutant, dark green (dg), contains higher level of chlorophyll in immature fruit and results in darker red pigmentation, both externally and internally in ripe fruit. Random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) analyses were performed using two pairs of near isogenic lines (NILs) designed to be isogenic at the hp and dg loci. Sixty-four AFLP primer pairs and more than 1000 RAPD 10-mer primers were screened for polymorphism between each pair of the NILs. One RAPD marker was identified to be linked to the hp gene, and two AFLP primer pairs showed polymorphic fragments which distinguished the dg NILs. The markers identified in this study will be converted to allele specific SCAR (sequence characterized amplified region) markers, which are more useful in marker-assisted selection breeding programs.