bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Morning and Afternoon Shade in Combination with Traffic Stress on Seashore Paspalum
Authors: Jiang Yiwei , Carrow Robert N. , Duncan Ronny R.
Published: February 2019

Turfgrasses are often exposed to different shade environments in conjunction with traffic stresses (wear and/or compaction) in athletic fields within stadiums. The objective of this study was to assess the effects of morning shade (AMS) and afternoon shade (PMS) alone and in combination with wear and wear plus soil compaction on `Sea Isle 1 seashore paspalum (Paspalum vaginatum Swartz). The study was conducted using two consecutive field trials under sports field conditions from 9 July to 10 Sept. 2001 at the Univ. of Georgia Experiment Station at Griffin. “T” shaped structures constructed of plywood on the sports field were used to provide §90% morning and afternoon shade, respectively, and were in place for 1 year prior to data accumulation. A wear device and a studded roller device simulated turfgrass wear (WD) and wear plus soil compaction (WSC), respectively, to the shaded plots. Only minor differences in turf color, density, or canopy spectral reflectance were found between AMS and PMS under no-traffic treatments in both trials. Grasses under WD generally recovered faster than those exposed to WSC across all light levels, including full sunlight (FL), AMS, and PMS. AMS combined with WD treatment had an average 9% higher rating of color, 11% higher density, and 28% less tissue injury than that of PMS with WD at 7 days after traffic treatment (DAT). Compared to PMS with WSC treatment at 7 DAT, AMS with WSC had 12% higher rating of color, 9% higher density, and 4% less tissue injury. AMS with WD treatment exhibited 11% higher normalized difference vegetation index (NDVI), 4% higher canopy water band index (CWBI), and 13% lower stress index than that of PMS with WD at 7 DAT. AMS with WSC, relative to PMS with WSC, demonstrated 8% higher NDVI, 3% higher CWBI, and 8% lower stress index at 7 DAT. Re sults indicated that AMS (i.e., afternoon sunlight) had less detrimental influences than PMS (i.e., morning sunlight) on turfgrass performance after it was subjected to wear stress or wear plus soil compaction.
Yield and Relationships among Head Traits in Cabbage as Influenced by Planting Date and Cultivar. II. Processing
Authors: Wszelaki Annette , Kleinhenz Matthew D.
Published: February 2019

This is the second of two related reports dealing with the effects of cultivar × environment interactions on cabbage (Brassica oleracea L., Capitata Group) crop traits. This study examined planting date and cultivar effects on physical head traits of processing cabbage and compared these findings to those from a similar study of fresh market cabbage. Six cultivars of processing cabbage were planted in May and June-July of 1999 and 2000 at the OARDC Vegetable Crops Research Branch in Fremont, Ohio. Marketable yield for each crop was determined, and measurements were taken of head weight, diameter, density, and volume, and core length, base width, and volume on more than 450 individual heads. Head and core volume and head density were calculated from these direct measures. Year, planting date, and cultivar significantly affected the majority of head traits. May planting led to higher marketable yield and heavier heads with larger diameters than June-July planting. The most variable trait across cultivars was head volume, which was affected by planting date in all cultivars. Differences between processing and fresh market cabbage were found. Average head polar/equatorial diameter values were affected by planting date in the fresh market but not the processing study. In contrast, head density and core volume as a percent of head volume were affected by planting date in the processing but not the fresh market study.
Ornamental Cabbage Quality Improved by Continual Fertilization through Center-head Coloration
Authors: Gibson James L. , Whipker Brian E.
Published: February 2019

Current fertilizer recommendations for ornamental cabbage (Brassica oleracea var. acephala DC.) suggest applying 150 to 300 mg·L-1 N until the initiation of color development, after which fertilization should be reduced or discontinued. Because these plants are actively growing during cool weather when coloration is initiated, nutrient deficiencies may reduce overall plant quality. The objectives of this study were to investigate N to K ratios for plant growth of ornamental cabbage and the effects of continual and discontinued fertilization during the period of coloration. Fertilizing with 150 to 200 mg·L-1 N and 150 to 200 mg·L-1 K produced high-quality plants and provided sufficient tissue concentrations of N and K. Center-head coloration was not inhibited by N concentrations as high as 250 mg·L-1. Ceasing fertilization prior to center-head coloration resulted in the rapid depletion of N, P, and K concentrations in the lower foliage, leading to the appearance of deficiency symptoms and lower leaf loss. Plants were still actively growing as measured by increased shoot mass during the early stages of coloration; therefore, growers should continue to provide a complete analysis fertilizer at N concentrations ≥150 mg·L-1 until market date.
Effects of Water Stress at Different Growth Stages on Greenhouse Tomato Yield and Quality
Authors: Nuruddin Molla Md. , Madramootoo Chandra A. , Dodds Georges T.
Published: February 2019

Tomatoes (Lycopersicon esculentum Mill. cv. Sunstart) were grown in a greenhouse during Summer 1999 and again in Winter 2000. Two available soil water (ASW) deficit thresholds, 65% and 80%, at which plants were irrigated to field capacity were factorially combined with five irrigation timing patterns: 1) no water stress; 2) stress throughout the entire growing season; 3) stress during first cluster flowering and fruit set 4) stress during first cluster fruit growth; and 5) stress during first cluster fruit ripening. Crop yields, water use efficiency, as well as maximum and minimum equatorial fruit diameters and fruit height were measured. Quality parameters of soluble solids, pH, and fruit color were also measured. Water stress throughout the growing season significantly reduced yield and fruit size, but plants stressed only during flowering showed fewer but bigger fruit than completely non-stressed plants. Consequently, on a weight basis the stressed at flowering and nonstressed plants had similar yields. Nonstressed and flowering-stressed fruit showed lower soluble solids and a lighter color of red ripe fruit than the other stress treatments. No significant differences in yield or quality were found between the two stress levels (65% vs. 80% ASW depletion before irrigation). Water stress only during flowering resulted in better yields and quality than stress at other specific developmental stages or at all times, but equal or poorer yields and water use efficiency than nonstressed plants.
Resistance of Watermelon Germplasm to the Peanut Root-knot Nematode
Authors: Thies Judy A. , Levi Amnon
Published: February 2019

Root-knot nematodes [Meloidogyne arenaria (Neal) Chitwood, Meloidogyne incognita (Kofoid & White) Chitwood, and Meloidogyne javanica (Treub) Chitwood] are serious pests of watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai var. lanatus] in the southern United States and worldwide. Watermelon cultivars with resistance to any of these nematode pests are not available. Therefore, we evaluated all accessions of Citrullus colocynthis (L.) Schrad.(21) and Citrullus lanatus (Thunb.) Matsum. & Nakai var. citroides (L.H. Bailey) Mansf.(88), and about 10% of C. lanatus var. lanatus (156) accessions from the U.S. Plant Introduction (PI) Citrullus germplasm collection for resistance to M. arenaria race 1 in greenhouse tests. Only one C. lanatus var. lanatus accession exhibited very low resistance [root gall index (GI) = 4.9] and 155 C. lanatus var. lanatus accessions were susceptible (GI ranged from 5.0 to 9.0, where 1 = no galls and 9 = ≥81% root system covered with galls). All C. colocynthis accessions were highly susceptible (GI range = 8.5 to 9.0). However, 20 of 88 C. lanatus var. citroides accessions were moderately resistant with a GI range of 3.1 to 4.0; overall GI range for the C. lanatus var. citroides accessions was 3.1 to 9.0. Resistance to M. arenaria race 1 identified in the C. lanatus var. citroides accessions was confirmed on a subset of accessions in a replicated greenhouse test. The results of our evaluations demonstrated that there is significant genetic variability within the U.S. PI Citrullus germplasm collection for resistance to M. arenaria race 1 and also identified C. lanatus var. citroides accessions as potential sources of resistance.
Photoperiod Effects upon Shoot Growth and Color of Bermudagrass Fertilized with Slow-release Nitrogen Sources
Authors: Quiroga-Garza Héctor Mario , Picchioni Geno A.
Published: February 2019

Total plant biomass, shoot growth rate, and the periodicity in shoot growth and color of hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy `Tifgreen'] in response to slow-release fertilizer N sources, rates, and application frequencies were studied in two, 120-day greenhouse studies. Plugs were planted in plastic cylinders filled with a growing medium of 93 sand: 7 peat moss (w/w). The first experiment was completed under progressively increasing photoperiod (13.1 to 14.9 hours) typical of the long-day requirements for bermudagrass growth. The second experiment occurred under progressively decreasing photoperiod (13.7 to 10.7 hours) representative of autumnal growing conditions and declining growth and N demand. Urea (URE), sulfur-coated urea (SCU), and hydroform (HYD, methylene urea polymers) were broadcast at N rates of 100 or 200 kg·ha-1 and at frequencies of 20 or 40 days. Bermudagrass was clipped at 3-day intervals and the average daily clipping growth rate (increase in shoot dry matter; DM) reached a maximum of 11.5 g·m-2 per day. Use of the least soluble source, HYD, produced the lowest total clipping DM, and at low HYD rate and frequency, leaf color intensity was frequently below the accepted standard of 7, in the scale from 1 “tan” to 9 “dark green”. A greater responsiveness of bermudagrass to N rate and application frequency (increased clipping growth rate and color intensification upon N application) occurred under increasing photoperiodic conditions as compared to decreasing photoperiodic conditions. Both clipping growth and color changed cyclically through time and mainly under long-day photoperiod (>12 hours), with greater oscillation at longer fertilization interval (40 days). With either SCU or URE, at low N rate and frequency (total N application of 0.25 g·m-2 per day), clipping growth rates were above 4 g·m-2 per day, and turf color was at or above the minimum quality standard through most of the growing period. Higher total SCU and URE application rates, previously shown to increase N leaching losses in these experimental conditions, produced significantly more clipping growth and did not appear to intensify color sufficient to warrant the increased risk of N loss.
Control of Mistletoe in Pecan Trees
Authors: Wood B.W. , Reilly C.C.
Published: February 2019

Semi-parasitic evergreen mistletoe (Phoradendron flavescens Nutt.) is an increasingly serious weed causing loss of nut yield and tree vigor in pecan [Carya illinoinensis (Wangenh.) K. Koch] orchards of the southeastern United States. Several herbicides and growth regulators were evaluated for efficacy against mistletoe. The dimethylamine salt of 2,4-D proved to be an effective control agent. Ethephon, glyphosate, paraquat dichloride, and polyborate exhibited little or no long-term efficacy. The dimethylamine salt of dicamba also killed mistletoe, but exhibited potential for harming host trees. Dormant season treatment of mistletoe clusters with 2,4-D reduced photosynthesis by about one-third soon after treatment, and by ≈90% from 6 to 16 weeks posttreatment, but clusters did not die until ≈4 months posttreatment. Host limbs, less than ≈3 cm in diameter at the site of mistletoe attachment, usually died within 12 months of 2,4-D treatment of the associated mistletoe cluster. Treatment of entire host trees with 2,4-D did not harm trees if applied prior to ≈1 week of budbreak. Spot treatment of mistletoe clusters, with 2,4-D at 1.2 to 2.4 g·L-1 a.i. (plus 2% crop oil), ≈2 to 3 weeks before budbreak, gave effective long-term control of mistletoe. The inclusion of a crop-oil in the 2,4-D spray greatly increased efficacy. Chemical names used: (2-chloroethyl) phosphonic acid (ethephon).
Response of Container-grown Apple Trees to Soil Compaction
Authors: Ferree D.C. , Streeter J.G. , Yuncong Y.
Published: February 2019

Container-grown apple (Malus ×domestica Borkh.) trees were exposed to soil compaction created by changing soil bulk density (SBD) to determine the effect of compaction levels, rootstock, and moisture stress on mineral nutrition, leaf gas exchange, and foliar carbohydrate levels. With SBD of 1.0, 1.2, and 1.4 g·cm-3, there was no interaction of rootstock and soil compaction for growth of `Melrose' trees on nine rootstocks. Trees grown in a SBD of 1.2 g·cm-3 had a greater dry weight than trees at 1.4 g·cm-3 bulk density. Increasing SBD to 1.5 g·cm-3 reduced shoot length, total leaf area, leaf size, and dry weight of leaves, shoots, and roots. The interaction between rootstock and SBD was significant and total dry weight of `B.9', `G.16', `G.30', and `M.7 EMLA' was less influenced by 1.5 g·cm-3 soil than trees on `M.26 EMLA' and `MM.106 EMLA'. Withholding moisture for 10 days at the end of a 70-day experiment caused 8% to 25% reduction in growth in a non-compacted (1.0 g·cm-3) soil with much less effect in a compacted soil. Prior to imposing the moisture stress by withholding water, net photosynthesis (Pn) was reduced 13% and transpiration (E) 19% by increasing bulk density to 1.5 g·cm-3. Following 7 days of moisture stress in non-compacted soil, Pn and E were reduced 49% and 36%, respectively, with no such reductions in the compacted soil. Increasing SBD to 1.5 g·cm-3 caused a decrease in the leaf concentration of quinic acid, myoinositol, and sucrose and an increase in fructose and glucose. Trees growing in 1.5 g·cm-3 had reduced concentrations of N, Ca, Mg, Mn, Na, and Zn, and increased P, K, B, and Fe in leaves.
Flowering, Sex Expression, and Fruiting of Pumpkin (Cucurbita sp.) Cultivars under Various Temperatures in Greenhouse and Distant Field Trials
Authors: Wien H.C. , Stapleton S.C. , Maynard D.N. , McClurg C. , Riggs D.
Published: February 2019

Field production of decorative pumpkins (Cucurbita pepo L.) in New York occasionally results in markedly delayed fruit production in spite of normal vine growth. These episodes of fruitlessness appear to be associated with periods of high temperatures. To determine the link between temperature and pumpkin flowering and fruiting, a series of multilocational field trials and confirmatory greenhouse experiments were carried out. The field trials were conducted in the summer seasons of 1996 and 1997 in Ithaca and Albany, N.Y.; Queenstown, Md.; and Bradenton, Fla.; and in Ithaca and Bradenton in 1998. Mean growing season temperatures were 20, 21, 24 and 28 °C, respectively, at the four locations in 1996 and 1997. Delay in fruit formation was indicated by the main stem node number at which the first fruit developed. In Ithaca and Albany, the six cultivars formed their first fruit at node 17, but fruit production shifted to node 24 at Queenstown, and to node 26 or more at Bradenton. The prolonged delay in fruiting at the warmest site resulted in a 74% decrease in total yield of the C. pepo cultivars in 1996 and 1997, compared to Ithaca and Queenstown. In contrast, the yields and yield components of the C. maxima cultivar Prizewinner were similar at all four sites. Greenhouse trials in which `Howden' and `Baby Bear' were grown at 32/27, 25/20, and 20/15 °C confirmed that high temperatures delay formation and anthesis of female flowers. This and other published work indicates that there are genetic differences in susceptibility to high temperature flower delay that could be exploited to improve pumpkin performance.
Leonardite Influences Zinnia and Marigold Growth
Authors: Dudley Jerry B. , Pertuit Alton J. , Toler Joe E.
Published: February 2019

The addition of leonardite may increase, or at least maintain, production quality of ornamental plants and permit reductions in fertilizer inputs. The objective of this study was to determine the effects of a Utah-mined leonardite on early stages of zinnia (Zinnia elegans Jacq. `Small World Pink') and marigold (Tagetes patula L. `Janie Yellow') growth. The Utah leonardite was characterized by comparing it to the International Humic Substances Society's leonardite standard. Zinnia and marigold seedlings and transplants were grown in sand and 1 sand: 1 peat media (by volume) with leonardite additions of 0%, 3.125%, 6.25%, and 12.5%. Both species showed positive growth responses to 3.125% leonardite in each medium compared to fertilizer alone. Plant responses to increased leonardite additions were generally quadratic, and optimal leonardite levels were estimated. For growing zinnias, optimal conditions were determined to be 7.5% leonardite in a sand medium for seedlings and 8% in a sand-peat mixture for transplants. A sand-peat medium containing 7% leonardite was determined to be optimal for growing marigold seedlings and transplants. Addition of leonardite to growing medium offers promise for reducing fertilizer use during production of some ornamental plants.
Growth Response of Hakonechloa macra (Makino) `Aureola' to Fertilizer Formulation and Concentration, and to Dolomitic Lime in the Potting Mix
Authors: Harvey Michael P. , Elliott George C. , Brand Mark H.
Published: February 2019

The shade-tolerant, variegated grass Hakonechloa macra `Aureola' is a valuable ornamental. In an experiment replicated in two growing seasons, Hakonechloa plants were fertilized at each irrigation (fertigation) with factorial combinations of three fertilizer formulations (N:P molar ratios 5:1, 10:1, and 20:1) at five N concentrations (2, 4, 8, 16, and 32 mmol·L-1), along with an unfertilized control, to determine the effect of N:P ratio and N concentration on vegetative growth and to establish fertility guidelines for production. Root dry weight and tiller bud growth increased slightly as N:P ratio increased. Fertilizer N concentration of 16 mmol·L-1 promoted the most shoot growth, whereas the number of tiller buds and root growth were greatest at 2 and 4 mmol·L-1 N. No interaction occurred between N:P ratio and fertilizer concentration. Results indicate that an N concentration of 8 mmol·L-1, with an N:P ratio of 10:1 or 20:1 is optimal for production of Hakonechloa. At this fertilizer concentration, the mean electrical conductivity of extracts obtained by a solution displacement extraction (pour-through) procedure was 2.3 ± 0.45 dS·m-1 (mean ± standard deviation). Tissue nutrient concentrations of N, P, K, Ca, and Mg were (in mg·g-1): 24.0, 2.8, 14.3, 2.1, and 2.1, respectively. In a concurrent study, Hakonechloa plants were grown in pine bark: peat: sand mix with dolomitic lime added at 0, 1.2, 3.6, and 9.5 kg·m-3 producing pH ranging from ≈4.5 to 7.2. Growth of Hakonechloa was greatest with no lime (pH 4.5) and declined markedly as the rate of lime increased. Concentrations of N, P, and K in shoot tissue were greatest at a pH between 4.5 and 5.6 (0 and 1.2 kg·m-3 dolomitic lime). These findings clearly support recommending production of Hakonechloa in soilless potting mix with pH ≈4.5 and constant fertigation with N at 8 mmol·L-1.
New Guinea Impatiens Growth Response and Nutrient Release from Controlled-release Fertilizer in a Recirculating Subirrigation and Top-watering System
Authors: Richards Daphne L. , Reed David Wm.
Published: February 2019

New Guinea impatiens (Impatiens hawkeri Bull.) `Illusion' were grown in a recirculating subirrigation system under various rates and placements of 14N-6.1P-11.6K (Osmocote; Scotts-Sierra, Marysville, Ohio) resin-coated, controlled-release fertilizer (CRF). Four CRF placements (incorporated, top-dressed, bottom, and dibble) were tested. Incorporated placement yielded slightly greater dry weights than the other placements. A rate experiment tested incorporating from 0.5 to 2 times the fertilizer manufacturer's recommended rate of 7.11 kg·m-3. All shoot growth parameters (height, leaf number, shoot, and root fresh and dry weight) exhibited a significant quadratic response, as exemplified by shoot dry weight, where shoot dry weight increased up to the 1.5× rate, after which shoot dry weight decreased. A quadratic response surface model revealed that the optimum rate response ranged from 1.16× rate for height to 1.47× rate for shoot dry weight. The lower bound of the 95% confidence interval (CI) would be the lowest rate at which one could expect maximum growth response. The lower bound of the 95% CI varied from 0.56× rate for height to 1.30× rate for shoot dry weight. Thus, the lowest rate that would be within the 95% CI for all growth parameters, and thus yield maximum growth response, would be the 1.30× rate. Electrical conductivity (EC) of the growing media increased significantly with increasing CRF rate. At all rates, EC was significantly greater in the top layer than in the middle and bottom layers. Only in the 1.75× and 2× rates did EC exceed the recommended EC levels in the middle and bottom layer. All rates >0.75× exceeded recommended EC in the top layer. Release characteristics and total nutrient balance of the CRF was compared in subirrigated and top-watered systems. There was no significant difference between top-watered and subirrigated treatments for the amount of K recovered in plant tops and released from prills. By day 84, in subirrigation, 46% of the K was still in the prills, 41% was recovered in the plant tops, and 22% was recovered in the medium. Similar results were obtained in the top-watering treatment, except that a lesser amount was recovered in the medium (9%) and a small amount (4%) was recovered in the leachate. The uptake of K by plants and release of K by the CRF were inversely proportional and linear with respect to time. Of the K released from the prills, 77% and 83% were recovered in the plant tops for subirrigation and top-watering, respectively, indicating very high fertilizer use efficiency.
Assessing the Integrated Pest Management Practices of Pennsylvania Nursery Operations
Authors: Sellmer James C. , Ostiguy Nancy , Hoover Kelli , Kelley Kathleen M.
Published: February 2019

A mail survey was conducted in 2000 to determine awareness and use of integrated pest management (IPM) practices by nurseries in Pennsylvania. Survey participants were randomly selected from the Pennsylvania Dept. of Agriculture, Bureau of Plant Industry, list of certified nurseries. Participants answered questions pertaining to awareness of common practices, frequency that IPM practices were employed, and specifics on monitoring and pest management decision-making processes. Responses were analyzed by Cluster Analysis (SPSS Inc., Chicago), which resulted in the formation of three distinct segments. The segments were labeled “IPM Savvy” (nursery managers who were more likely to employ IPM practices); “Part-time IPMers” (nursery managers who employed some IPM strategies and were interested in future adoption of IPM practices); and “Reluctant IPMers” (nursery managers who were least likely to employ IPM strategies). The “Part-time IPMers” and “Reluctant IPMers” segments represent a substantial part of the industry (51%), who continues to have concerns about the cost, efficacy, and implementation of IPM practices into their businesses. Overall, Pennsylvania growers are aware of IPM practices; however, maintaining permanent records of pests identified and pest management strategies employed remain low. Continued education is warranted to enhance pest monitoring skills and recordkeeping along with demonstrable evidence to the cost effectiveness and marketing benefits that the implementation of IPM practices offer the nursery operators.
Inheritance of Style Color in Hazelnut
Authors: Mehlenbacher Shawn A. , Thompson Maxine M.
Published: February 2019

The style color of standard hazelnut (Corylus avellana L.) cultivars ranges from pink to dark purple. Styles with an unusual yellow color were first noted in seedlings of the progeny `Goodpasture' × `Compton', and the ratio was ≈3 red: 1 yellow. Controlled crosses were made to investigate the genetic control of style color. The same 3:1 ratio was observed in four additional crosses in which both parents had red styles. Two crosses of a red and a yellow parent gave ≈50% yellow styles, while a cross of two selections with yellow styles gave only seedlings with yellow styles. These segregation ratios indicate control by a single locus, with yellow style color recessive to red. Seedlings with yellow styles have green buds and catkins and a more upright growth habit than their siblings with red styles. Inspection of the pedigrees of these progenies shows that `Daviana', `Willamette', `Butler', `Compton', `Goodpasture', and `Lansing #1' are heterozygous. `Daviana' appears to be the original source of the allele for yellow styles, as it is a known or suspected parent or ancestor of the others. Ratios in a progeny segregating simultaneously for growth habit (normal vs. contorted) and style color indicated independence of the traits. However, in a progeny segregating simultaneously for leaf color (red vs. green) and style color, no redleaf seedlings had yellow styles. The S-alleles of eight genotypes with yellow styles were determined, and indicate a possible linkage between the yellow style locus and the S locus that controls pollen-stigma incompatibility. One explanation is that the yellow style trait is conferred by an allele (ays) at the anthocyanin (A) locus that controls leaf color. A second explanation is that there is a yellow style locus closely linked to the A locus. The A locus is known to be loosely linked to the S locus.
Repeatability and Minimum Selection Time for Fatty Acid Composition in Olive Progenies
Authors: León L. , Martín L.M. , Rallo L.
Published: February 2019

Fatty acid composition has been studied in seedlings from a diallel cross (nine families) among `Arbequina', `Frantoio', and `Picual' olive (Olea europaea L.). Variance among samples within genotype, genetic and environmental (yearly) variances, and year-to-year consistency of data were estimated. A correlation analysis of the standardized data for fatty acid composition between first and second year data was also carried out to select the most interesting genotypes as early as possible. The results showed that fatty acid composition exhibit significant differences between genotypes and years. The variance component attributable to differences between genotypes represented >60% of total variance for all the fatty acids evaluated. High correlation coefficients between the first and second year data were found for oleic and linoleic acid percentage; these correlations were slightly poorer for the other fatty acids analyzed. These results may be useful for improving the efficiency of olive breeding programs in first-stage selection on whole progeny populations.
Effects of Restricted Watering and CO2 Enrichment in the Morphology and Performance after Transplanting of Nursery-grown Pinus nigra Seedlings
Authors: Biel Carme , Savé Robert , Habrouk Abdessamad , Espelta Josep Maria , Retana Javier
Published: February 2019

Extensive areas occupied by Pinus nigra forests in Spain have burned in recent years. Recovery of these forests depends upon reforestation. In this study, we analyze the combined effects of different treatments of water restriction and air enrichment with CO2 in the nursery as a means to increase hardening and vigor of P. nigra seedlings of various ages (recently germinated, 1- and 2-year-old) and their post-transplant performance in a burned area. In all cases, 2-year-old seedlings showed the highest specific leaf weight and low cuticular transpiration rates. CO2 enrichment increased total biomass, leaf biomass and leaf area of seedlings while water restriction decreased leaf area, leaf biomass, and stem biomass, without any significant interaction between both experimental factors. Younger (recently germinated and 1-year-old) seedlings showed a larger relative response to the experimental factors than 2-year-old seedlings. After transplanting, the previous CO2 and water treatments did not affect seedling survival, but 2-year-old seedlings showed the lowest mortality rates.
Effects of Tissue Phosphorus and Nitrogen in Impatiens wallerana on Western Flower Thrips (Frankliniella occidentalis) Population Levels and Plant Damage
Authors: Chen Yan , Williams Kimberly A. , Harbaugh Brent K. , Bell Michelle L.
Published: February 2019

Host-plant nutritional status may affect the incidence and development of western flower thrips (WFT; Frankliniella occidentalis Pergande). Two greenhouse experiments were conducted to determine the responses of WFT population levels on impatiens (Impatiens wallerana Hook.f.) when plants were fertilized with commercially practiced rates of nitrogen (N) and phosphorus (P). Impatiens `Dazzler Violet' were grown with nutrient treatment combinations of 2 N rates (8 and 20 mm) by 2 P rates (0.32 and 1.28 mm). Individual plants grown in thrips-proof cages were inoculated with WFT at 2 or 4 weeks after transplant, in separate experiments, representing vegetative or reproductive stages of plant growth, respectively. Plants were destructively sampled weekly for 4 weeks following inoculation. Plant tissue N and P concentrations were significantly different across treatments: 8 and 20 mm N resulted in 4.9% and 6.3% N in tissue, respectively; 0.32 and 1.28 mm P resulted in 0.37% and 0.77% P in tissue, respectively. Nitrogen rates had no effect on WFT population levels. However, 4 weeks after inoculation with adult female WFT during the vegetative growth stage, plants fertilized with 1.28 mm P had more adult WFT than those fertilized with 0.32 mm P. Feeding damage varied depending on whether plants were inoculated in the vegetative stage with adult WFT or during reproductive growth with immature WFT. Plant size and number of flowers were lower in plants inoculated during the vegetative growth stage with adult WFT but were not affected when inoculation with immature WFT occurred during the reproductive stage, as most WFT were found feeding inside the nectariferous spurs of the flowers. Tissue N was lower in WFT-inoculated plants compared to noninoculated plants in both experiments.
Water Content of a Pine-bark Growing Substrate in a Drying Mineral Soil
Authors: Hanson Anne-Marie , Harris J. Roger , Wright Robert , Niemiera Alex , Persaud Naraine
Published: February 2019

Newly transplanted container-grown landscape plants are reported to require very frequent irrigation. However, container nurseries in the U.S. commonly use growing substrates that are mostly bark, even though the contribution of bark-based growing substrates to water relations of transplanted root balls is unknown. Therefore, a field experiment was undertaken to determine water relations of a pine-bark substrate (container removed) within a drying mineral soil over a three week period. A range of common production container sizes—3.7 L (#1), 7.5 L (#2), 21.9 L (#7), 50.6 L (#15), and 104.5 L (#25)—was used. The fraction of substrate volume that is water [total volumetric water (TVW)] within the top and middle zones of substrate was compared to TVW at corresponding depths of adjacent mineral soil. The fraction of substrate and soil volume that is plant-available water [plant-available volumetric water (PAVW)] was calculated by subtracting the fraction of substrate or soil volume below where water is unavailable to most plants (measured with pressure plates) [plant-unavailable volumetric water (PUVW)] from each TVW measurement. The pine-bark substrate had a PUVW of 0.32 compared to a PUVW of 0.06 for soil. Top sections of substrate dried to near zero PAVW 6 days after irrigation for all containers. Larger container sizes maintained higher PAVW in middle sections than smaller container sizes, and PAVW was always higher in the adjacent soil than in the embedded substrate. Overall, very little PAVW is held by the embedded pine-bark growing substrate, suggesting the need for container substrates with greater water retention once transplanted to mineral soils.
Effects of Canopy and Micro-irrigation under the Trees on Spatial Variations of Soil Labile Phosphorus and Metals in a Citrus Grove
Authors: He Zhenli , Calvert David. V. , Stoffella Peter. J. , Zhang Mingkui
Published: February 2019

To evaluate effects of canopy and micro-irrigation under trees on accumulation and leaching of phosphorus (P) and heavy metals in agricultural sand soils, the horizontal and vertical variations of soil P and metals in a 408-m2 plot within a grove under grapefruit (Citrus paradisi Macf.) production near Fort Pierce, Fla., was examined. A high horizontal variation of labile soil P and metal concentrations was observed. Across the row, the highest values of pH, EC, water-soluble P, and all metals occurred in the soils under the canopies, and the lowest values occurred in the soils near the water furrow or the midway of the inter-row. Along the grapefruit row, the highest values of many measured variables occurred along the northern side of the citrus tree and close to the emitter. The downward movement of P, Cu, and Zn in the soils was more significant in the soils in open areas (near the water furrow and midway of inter-neighboring trees) than those under the canopies. The differences in labile P and metal spatial distributions in the soils were related to the location of emitter fertigation and differences in rainfall-induced leaching in the field. The results suggest that applying fertilizers to sites under the canopy rather than the spaces between the trees can minimize leaching losses of nutrients.
Feeding and Oviposition Behavior of Diaprepes abbreviatus (L.) on Peach Prunus persica L. in Puerto Rico
Authors: Delgado Alexandra , Gonzalez* Angel L. , Del C. Libran Maria
Published: February 2019

Peach cultivars are being evaluated for their adaptation to the conditions of the central region of Puerto Rico. The root weevil, Diaprepes abbreviatus (L.), a common insect pest in the area, is being previously reported on peach trees. With the purpose of evaluating the potential feeding damage that this insect might represent for future peach production, choice and no-choice tests were made with leaf discs (feeding) and leaf strips (oviposition) to determine adult feeding and oviposition behavior in comparison with `Navel' orange. Larval feeding behavior on the roots was studied on a peach rootstock and `Cleopatra' mandarin planted in 18.9-L containers. In the no-choice test, adults fed significantly more on `Navel' orange foliage than on peach foliage. In the choice test, adults preferred to feed on `Navel' orange leaf discs. Oviposition occurred on both peach cultivars tested, but more egg masses were laid on Navel orange leaf strips in the no-choice test. However, given the choice, adults preferred to oviposit on peach leaf strips while fed on `Navel' orange leaf strips. In some replications this behavior was reversed. At 90 days after infestation, larval feeding damage on the roots was severe on `Cleopatra' mandarin where most of the cortex tissue on the primary root was removed and growth of roots and foliage was reduced. Larvae bore also on peach trees, but there was no sign of growth reduction on foliage or the roots compared to the control. These preliminary results indicate that D. abbreviatus will not be a primary pest on peach.
Functional Characterization of S-adenosylmethionine Decarboxylase and Spermine Synthase Genes from Apple
Authors: Kitashiba* Hiroyasu , Hao Yu-Jin , Honda Chikako , Kita Masayuki , Moriguchi Takaya
Published: February 2019

Polyamines [putrescine (put), spermidine (spd), and spermine (spm)] are aliphatic amines that are implicated in the regulation of many basic physiological processes such as cell growth, proliferation and stress responses in organisms including plants (Walden et al. 1997). Put is metabolized to spd and spm through the successive enzymatic reactions of spd synthase (SPDS) and spm synthase (SPMS) with the use of decarboxylated S-adenosylmethionine (dcSAM) as an aminopropyl donor, which is generated by SAM decarboxylase (SAMDC). So far, two MdSAMDC (MdSAMDC1 and MdSAMDC2) homologous to SAMDC and two MdACL5 (MdACL5-1 and MdACL5-2) homologous to ACL5 encoding SPMS in Arabidopsis (Hanzawa et al. 2000) were isolated from `Orin' apple. To investigate the function of these genes, complementation analyses were carried out using yeast mutants. Each of the MdSAMDCs consists of three ORFs; tiny- and small-ORFs in the 5' regions, and main ORF like other plant SAMDC genes. Both constructs for MdSAMDC containing all ORFs (SAM-DCall) or containing only main ORF (SAMDCorf) were capable of recovering the growth of yeast SAMDC-deficient mutants (delta spe2) without supplement of spd, although the SAMDCall constructs always showed the lower growth speed than the SAMDCorf constructs. On the other hand, yeast SPMS-deficient mutant (delta spe4) introduced by MdACL5 cDNA produced significantly higher amount of spm than the delta spe4 with control vector by HPLC. Collectively, these results suggest that both MdSAMDCs are functional as a SAMDC and the tiny- and small-ORFs are negative-regulatory factor for the translation efficiency of SAMDC, and also that MdACL5 encodes a functional SPMS like as ACL5 in Arabidopsis. The first and second authors contributed equally to this work.
Differential Expression of rolC Results in Unique Plant Phenotypes
Authors: Smith* Alan G. , Gardner Nicole , Melberg Tracy A.
Published: February 2019

As residential lot sizes decrease, there is an increased demand for new, small-statured landscape plants to fit into the smaller lots. One promising method to create smaller plants is by introducing a dwarfing gene into a plant of interest. A dwarfing gene that has been identified is the rolC gene from Agrobacterium rhizogenes. Expression of rolC in plants has been shown to cause decreased height and internode length, increased branching, and modified leaf size in a several species. Although the effects of the rolC gene have been well characterized for many plant species, most research has concerned the native promoter or the CaMV 35S promoter. Less research has been done with additional promoters or comparing the results from different promoters. In this study we examined the effects of three separate gene constructs, all containing rolC driven under either the 35S promoter, the light inducible rbcs promoter, or the native rolC promoter in tobacco. Plants transformed with these constructs ranged widely for height and other phenotypic traits. Representative plants were crossed back to wild-type tobacco. Plants from this next generation, six with the 35S promoter, six with the rbcs promoter and four with the native rolC promoter, were measured for traits such as height, days to flower, number of branches and internode length. RolC RNA expression levels were also measured in roots, stems, and leaves to determine correlations between rolC expression level in specific tissues and the observed phenotype. Information about these relationships can be used to provide insight into the use of rolC in ornamental plants and the potential to modify its phenotypic effects by controlling expression level.
DNA Analyses of the Genus Dirca L. (Leatherwoods)
Authors: Schrader James A. , Graves* William R.
Published: February 2019

Long regarded as a genus of two species, Dirca L. was expanded to include a third North American shrub discovered in 1994 as one population in the Sierra Madre Oriental of Tamaulipas in northeastern Mexico. The designation of Dirca mexicana Nesom & Mayfield as a third species in the genus was based in part on geographical separation from Dirca palustris L. and Dirca occidentalis Gray, which occur farther north in eastern North America and in a small region of California, respectively. Morphologically, D. mexicana was regarded as more similar to D. occidentalis than to D. palustris. Our objectives were to obtain fruits of all species, germinate seeds, and compare the three species genetically through analyses of seedling DNA. Drupes of D. mexicana, D. palustris (from populations in Iowa), and D. occidentalis were collected as they abscised naturally from plants in native habitats in mid-May, late May to early June, and mid-June, respectively. Embryo extraction, gibberellin, and cold stratification were used to promote germination, and DNA was extracted from leaves of seedlings by using the fully automated Autogen Autogenprep 740 DNA extraction system. Genomic DNA templates were used to compare sequences of the internal transcribed spacers (ITS) and the 5.8S coding region of the nuclear ribosomal DNA repeat and to examine polymorphisms in inter-simple sequence repeats (ISSRs). These analyses reinforce the present morphologically based classification of the three Dirca species by confirming species-level divergence at the molecular level. ITS sequences and ISSR banding patterns also enabled us to reconstruct the phylogenetic relationship among the three extant species of Dirca.
Out Season Onion Production Using `Sterling' Variety in Northwestern Mexico
Authors: Macias-Duarte Ruben , Grijalva-Contreras* Raul Leonel , de Jesus Valenzuela-Ruiz Manuel , Robles-Contreras Fabian
Published: February 2019

In Northwestern Mexico, the sowing, transplant and vegetative development of onion bulb coincide with the winter and the harvest with the end of the spring. During the summer, this vegetable can't be produced because there were no varieties that develop appropriately under the high temperature and constant humidity characteristic of this time of the year. For this reason, in autumn and winter. there exists a shortage of onion in the market being increased the value of the same one. The objective of the present investigation was to evaluate and to develop a methodology to produce onion bulb in autumn. This experiment was carried out at INIFAP-CIRNO Experimental Station on. The white variety used was `Sterling' of long photoperiod. The plant establishment was on 27 Apr. 2002 (82 days after sow date) in this trial we used furrows to double row, with 1.00-m separation among them. Fertilization with nitrogen and phosphorus (180 and 80 kg·ha-1 respectively), during the growing season using drip irrigation system. Two application were applied against the fungous disease (Metalaxil + Clorotalonil). Our results indicate that the bulb obtained had a globe form with good quality and firmness. The harvest time was from 7 to 10 Sept., with means bulb weight of 214 grams and a yield of 36.5 t·ha-1.
Moisture Contents in Bottle Gourd Seeds during Dry Heat Treatment and Subsequent Germination
Authors: Lee* Seung-Hee , Kim Jin-Seok , Lee Jung-Myung
Published: February 2019

Dry heat treatment (DHT), a powerful and agrochemical-free means of inactivating seed-borne virus and other pathogens, has been extensively used for value-added vegetable seeds in Korea, Japan, and some other countries. Since seeds are treated with extremely high heat (75 °C or higher) for a long time (72 h or longer), heat-induced phytotoxicity symptoms are frequently observed. Even though various internal and external factors, such as seed maturity and vigor, maximum temperature and duration of DHT, are known to influence the severity of phytotoxicity, precise control of seed moisture contents during DHT is regarded as one of the most important factors for successful DHT. In an ideal condition using a specifically designed DTH machine, seed moisture content of bottle gourd, initially around 6.20% to 0.64% when stored in a storage room with 50% RH, decreased by 1% after 24 h at 35 °C (5.20% to 0.23%), and further decreased below 4% after 24 h pretreatment at 50 °C (3.64% to 0.37%). The seed moisture content was further reduced down to about 2% after 72 h DHT at 75 °C (2.16% to 0.28%). During the post-treatment conditioning at 50 °C and 70% RH for 24 h, the moisture contents were raised to about 6%(5.94% to 0.45%), thus approaching the initial moisture content of 6% to 7%. During the germination period, treated seeds showed slower absorption of water as compared to the intact seeds, thus suggesting that this slow absorption of initial moisture absorption may be responsible for the slow initial germination frequently observed in treated seeds. Final germination and seedling vigor were not affected by DHT.
Phytochemical Profile Changes of Tomatoes in Response to Altered Light Environments
Authors: Ellingson* Katherine A. , Rajapakse Nihal C. , Riley Melissa B.
Published: February 2019

Recent medical interest in plant antioxidants in human health has stimulated the interest in functional phytochemicals of fruits and vegetables. Numerous reports link antioxidant capacity of phytochemicals to the reduction of degenerative diseases. As a result, sales of herbal antioxidant supplements have increased tremendously although negative (or no) effects have been documented with certain supplements. There are many interactive reactions among phytochemicals. At this point, our understanding of interactions among phytochemicals is limited. Therefore, medical professionals are reluctant to prescribe supplements as a mean to boost antioxidants, but they agree that consumption of fresh fruits and vegetables is essential for a healthy life and provides a better alternative than supplements to boost antioxidant uptake. Carotenoids are receiving attention because of their pro-vitamin A activity and antioxidant properties. Two of the widely investigated carotenoids for improvement are lycopene and β-carotene. Genetic composition, cultural practices, environmental conditions, and processing can all affect carotenoid profiles. Light has been shown to affect carotenoids and we are investigating if changing the spectral composition in the growing environment can alter carotenoid levels. Preliminary results show that tomatoes grown under a high red light environment have increased lycopene and overall carotenoid contents. Nutritionally enhanced produce will benefit both growers and consumers.
Position of Source Leaf Affects Translocation and Distribution of C14 Photo-Assimilates in Tomato
Authors: Lee* Sang Gyu , Lee Chiwon W.
Published: February 2019

The relationship between source leaf position and the photo-assimilate translocation and distribution was characterized for tomato (Lycopersicon esculentum Mill.) grown in the greenhouse. Three different positions of source leaf on the stem (first node above or below the first fruit cluster and fifth node above the first fruit cluster) were tested for their influence on 14CO2 assimilation and transfer to different parts of the plant. The leaves at the fifth node above the first fruit cluster transferred the highest (57%) proportion of C14 to other plant parts, followed by leaves borne on the first node below the first fruit cluster (50%), and the first node above the first fruit cluster (39%). In all treatments, fruits served as the strongest sink for C14, followed by stem, leaf, and root tissues. The leaf borne on the fifth node above the first fruit cluster transferred the largest amount of C14 to the second fruit cluster.