bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Ten Plant Source Origins on Field Performance of 'Sweet Charlie' Strawberry in Florida
Authors: Cady Suzanne W. , Chandler Craig K. , Legard Daniel E. , Price Jim F. , Sumler Jim C.
Published: February 2019

The objective of this study was to compare plant health and growth in Florida fruiting fields of `Sweet Charlie' plants from 10 different plant sources. Bare-root plants from Ontario, Nova Scotia, Massachusetts, Oregon, North Carolina, Alabama, and Florida and plug plants from North Carolina and Florida were compared in a RCBD of four replicates. Plants were rated for vigor, production, diseases, and pests throughout the 1995-96 season. Crown size of transplants ranged from 7 to 12 mm. Plants from northern sources exhibited angular leaf spot (Xanthomonas fragariae) and gnomonia (Gnomonia spp.) while southern-raised plants were infected with phomopsis (Phomopsis obscurans) and anthracnose (Colletoctrichum spp.). Initial ratings confirm the potential for aphids and two-spotted spider mites (Tetranychus urticae) to be introduced on transplants. Plants from northern origins flowered 10-14 days earlier than plants produced in southern regions. Total season marketable fruit production was not statistically different among the eight bare-root treatments. Monthly fruit production was significantly different among treatments for all months except February. Performance of plug plants compared to bare-root plants of the same geographic origin were inconsistent. Initial crown size, average berry size, and cull fruit production were significantly different among the plant sources. In summary, clear differences in foliar diseases and monthly fruit production were strongly associated with transplant source. A strawberry farmer may maintain more stable production throughout the year by using transplants from several geographic origins.
Effect of Three Different Planting Patterns on the Yield of Four Sweetpotato [Ipomoea batatas (L.) Lam] Cultivars
Authors: Khan V.A. , Stevens C. , Wilson M.A. , Lu J.Y. , Rhoden E.G. , Collins D.J. , Brown J.E.
Published: February 2019

In 1995 a study was conducted in split-split-plot design to determine the effect of single, double, and equilateral planting configurations with a single and double recommended rate of fertilizer (NPK), would have on the yield of four sweetpotato cultivars. TU-1892, Jewel, TU-82-155, and Georgia Jet were planted on a raised shaped bed 2 ft wide. Fertilizer was banded in the center of the bed and plants were then placed 6 inches away on both sides of this band for the double and equilateral configurations and on one side for the single configuration. Plants were spaced 12 inches apart within rows and the rate of fertilizer used for both single and double rows was the recommended rate for single rows. All plots were side dressed with an additional 80 lbs/acre of K at the time of flowering. Marketable yield data showed that by doubling the recommended rate of fertilizer yield increased for all cultivars which ranged from 26%-41% for single, 35%-88% for double, and 64%-104% for equilateral configurations, respectively. The results also indicated that net returns for TU-1892 was 217%, Jewel 136%, TU-82-155 203%, and Georgia-Jet 171%, for double and equilateral configurations, respectively, when the rate of fertilizer was doubled.
Influence of Cold Water Priming on Spinach Seed Performance
Authors: Willis Leah E. , Motes James E.
Published: February 2019

Six experiments were conducted to determine the effect of priming on spinach seed performance. Performance was determined by percent, uniformity, and speed of germination after 10 days. In Expt. 1, performance at 22 °C was improved for primed seeds compared to unprimed seeds and germination was >90% for both primed and unprimed seeds. In Expt. 2 (incubator @ 40 °C for 16 h/30 °C for 8 h), germination was reduced for both seed treatments and primed seeds had more germination, but less uniformity than unprimed seeds. In Expt. 3 (incubator @ 40 °C for 16 h/30 °C for 8 h), initial temperatures were 40 °C for 16 h, 40 °C for 8 h, or 30 °C for 8 h. There was an interaction between priming and initial temperature for percent germination, indicating that only primed seeds varied in response to initial temperature. Priming improved percent germination but reduced uniformity and did not influence speed of germination. In Expt. 4 (growth chamber @ 40 °C for 16 h/30 °C for 8 h), priming significantly improved percent seedling emergence and speed compared to unprimed seeds but did not influence uniformity. In Expt. 5 (growth chamber @ 40 °C for 16 h/30 °C for 8 h) initial temperatures were 40 °C for 16 h, 40 °C for 8 h, or 30 °C for 8 h. Priming significantly improved seedling emergence and speed and did not affect uniformity of emergence. Seedling emergence was significantly improved for seeds planted at an initial temperature of 40 °C compared to 30 °C.
Reduction of Tomato Early Blight by Combining Soil Solarization and Biological Control Strategies
Authors: Stevens C. , Khan V.A. , Ploper L.D. , Backman P. , Rodriguez-Kabana R. , Collins D.J. , Brown J.E. , Wilson M.A.
Published: February 2019

Combinations of solarized soil (SBS), bare soil control (BS), black plastic mulched soil (BM), row cover (RC), fungicide (chlorothalonil) and biological treatments (Bacillus cereus) were evaluated. SBS vs. BS treatments were main plots, mulch and row covers splitplots and foliage treatments split-splitplots. Application of either foliar treatment was superior to BS. Using a 1/2 rate of fungicide on plants from solarized soil treatments showed equal or comparable reduction of the disease when compared to tomatoes grown in BS with high rates of the fungicide. Combined treatments of solarized + BM, BM with or without RC and low rate of fungicide or biological agent, were the most effective when compared to BS + fungicide, indicating that integration of plasticulture and biological strategies can reduce early blight below the levels of commercial fungicide applied to tomatoes grown on BS.
Practical Application of PCR-based Technology to Screen Texas Onion Breeding Lines for Cytoplasmic Male Sterility
Authors: Alcala J. , Lopes J.F. , Giovannoni J.J. , Pike L.M.
Published: February 2019

Identification and production of onion male-sterile and maintainer lines by conventional breeding takes between 4 to 8 years, due in part to the biennial nature of onion. In addition, male sterile plants and maintainer genotypes occur at a very low frequency in onion populations (Pike, 1986). A significantly shorter and more efficient alternative involves the screening of breeding lines for cytoplasmic male sterility using PCR-based technology. Thirty short-day onion breeding lines from the Texas A&M onion program were screened for type of cytoplasm (normal or sterile). Specific amplification of a fragment of chloroplast genome was achieved using the polymerase chain reaction according to Havey (1991). Forty-eight individual onion plants were screened per line. Out of thirty lines evaluated, 13 showed 100% sterile cytoplasm, 6 showed 100% normal cytoplasm, and 11 showed both types of cytoplasm. Lines showing normal cytoplasm or both cytoplasmic types were kept and reanalyzed. Only plants presenting normal cytoplasm were grown to maturity to help in the identification of maintainer lines as part of the Texas A&M onion breeding program.
End-of-Day Light Quality Effects on Growth and Development of Watermelon Plants
Authors: Ranwala N.K. Damayanthi , Decoteau Dennis R.
Published: February 2019

End-of-day (EOD) red (R) or far-red (FR) light treatments were used to study phytochrome-regulated growth and dry matter distribution in 2-week-old watermelon plants. Plants were exposed to low-intensity R or FR light for 15 min at the end of photoperiod for 9 consecutive days. End-of-day FR increased the petiole elongation in the first two leaves, which was accompanied by higher dry matter partitioning to the petioles after 3 days of treatments. However, total plant dry mass (above ground) in FR-treated plants increased significantly after 6 days of treatments. This indicates EOD FR regulated dry matter compensation among plant parts at the early stages of EOD light treatments, allowing plants to better adapt to the environment. Net CO2 assimilation rate in the second leaf of FR-treated plants also increased. Phytochrome involvement in these processes is suggested, since growth and dry matter distribution patterns were reversible when plants were treated with FR immediately followed by R.
Propagation of Erect Blackberries by Floricane Stem Cuttings
Authors: Lopez-Medina Jose , Moore James N.
Published: February 2019

An experiment was carried out to investigate whether detached segments of floricanes during winter pruning of erect blackberries could be used as a source of propagating material. Portions of lateral branches from `Arapaho', `Navaho', `Choctaw', and `Shawnee' field-grown plants, subdivided according to their position on the cane (tip, middle, and base), and treated with or without 0.3% IBA in talc were stuck in peat—perlite mix under intermittent mist in greenhouse conditions. Differences in percentage of cuttings rooted occurred only for cultivars; `Arapaho' rooting the highest (99%) and `Shawnee' the lowest (83%). IBA improved volume of roots formed. Cultivar by position interaction effect was evident for volume of roots, percentage survival of cuttings after potting, percentage shoot formation, and dry weight of shoots and roots, with highest values for stem cuttings taken from the middle of canes of `Arapaho' and lowest for basal cuttings of `Shawnee'. `Choctaw' stem cuttings produced the largest shoots regardless of their position or treatment with IBA. These findings suggest that propagation of erect blackberries by floricane stem cuttings is feasible. This work might be useful to plant breeding, either for early collection of pollen or in controlled pollinations.
Effect of Selected Growth Retardants on `Arabe' Grapevines
Authors: Morales-Salazar Gonzalo , Morales-Payan Jose P. , Santos Bielinski M.
Published: February 2019

The effect of three plant growth retardants, bitertanol, tradimefon, and hexaconazole, on short-term vine regrowth of pruned `Arabe' grape (Vitis vinifera) was studied in field experiments conducted in the Dominican Republic. Individual soil drench treatments of the three retardants were applied to adult pruned `Arabe' grape plants at rates 0, 0.25, 0.50, 0.75 and 1.00 g active ingredient per plant. Three weeks after treatment, bitertanol did not have a significant effect on vegetative growth, whereas triadimefon and hexaconazole caused significant reductions on vine regrowth. The effect of triadimefon as a growth retardant was stronger than that of hexaconazole, as described by regression equations Y = 30.88 - 25.68X for triadimefon, and Y = 32.9 - 15.2X for hexaconazole.
Effect of Gibberellic Acid 3 and Nitrogen on the Seedlings of the Tropical Fruits Malpighia punicifolia, Spondias dulcis, and Melicoccus bijugatus
Authors: Morales-Payan Jose P. , Santos Bielinski M.
Published: February 2019

Container experiments were conducted in the Dominican Republic to determine the effects of gibberellic acid (GA3) and nitrogen (N) treatments on the seedling growth of Spanish lime (Melicoccus bijugatus), golden apple (Spondias dulcis), and acerola (Malpighia punicifolia). The three species responded with linearly increased height and dry weight to increasing GA3 levels. Each species responded differently to N rates. Spanish lime did not respond to N supply, whereas golden apple was highly responsive and the growth of acerola was reduced at high N rates.
Effect of Exogenous Gibberellic Acid on Papaya Ringspot Virus (PRSV)-Infected Papaya
Authors: Morales-Payan Jose P. , Morales-Salazar Gonzalo , Santos Bielinski M.
Published: February 2019

Field and container experiments were conducted in the Dominican Republic to determine the effect of gibberellic acid 3 (GA3) rates on papaya ringspot virus (PRSV)-infected seedlings and adult plants of `Cartagena Ombligua' papaya. The apical region of PRSV-infected and PRSV-uninfected plants was sprayed with GA3 aqueous solutions at rates 0, 25, 50, 75, and 100 ppm. PRSV-uninfected adult plants and seedlings produced longer internodes as GA3 rates increased. Adult PRSV-uninfected plants flowered normally at any GA3 rate. PRSV-infected seedlings and adult plants also responded to GA3 sprays, but to a lower extent. Typical symptoms of the disease were present in all the infected plants regardless of the GA3 rate applied, and adult plants did not flower at any rate. Results indicate that PRSV-infected `Cartagena Ombligua' papaya plants are responsive to exogenous GA3, although in a lesser degree than PRSV-uninfected plants. Linear regression equations described the effect of GA3 on the stem elongation of PRSV-infected and uninfected `Cartagena Ombligua' seedlings and adult plants.
Response of Young `Keitt' Mango Trees to Nitrogen and Gibberellic Acid Supply
Authors: Morales-Salazar Gonzalo , Santos Bielinski M. , Morales-Payan Jose P.
Published: February 2019

Field experiments were conducted in the Dominican Republic to determine the effect of gibberellic acid (GA) and nitrogen (N) treatments on the growth of lateral branches in young `Keitt' mango plants. Two-year-old `Keitt' mango plants were pruned and treated with combinations of gibberellic acid (0, 20, 40, 60, 80, and 100 ppm) foliar sprays and soil nitrogen fertilization (18.75, 37.50, and 56.25 g). There were no N by GA interactions. Treatments did not significantly influence days to sprouting, number of sprouts, or number of leaves per sprout. N rates did not affect sprout length, whereas increasing GA rates enhanced sprout elongation. The effect of GA was described by the linear equation Y = 14.59 + 0.27X. Results indicate that GA sprays can be used to enhance sprout elongation to promote the desired round shape in canopies of `Keitt' mango plants.
Effect of Exogenous Gibberellic Acid on the Growth of Young `Hall' and `Semil-34' Avocado Trees
Authors: Morales-Salazar Gonzalo , Morales-Payan Jose P. , Santos Bielinski M.
Published: February 2019

Field experiments were conducted in the Dominican Republic to determine the effect of gibberellic acid treatments on the elongation of the leading and lateral branches of `Hall' and `Semil-34' avocado (Persea americana) plants. The plant growth regulator was applied as a foliar spray to the leading branch at rates 0, 20, 40, 60, and 80 ppm. `Hall' avocado was not responsive to gibberellic acid treatment, whereas `Semil-34' was responsive, with higher rates inducing a more pronounced stem elongation. As an undesirable side effect, gibberellic acid treatment also stimulated the elongation of lateral branches in `Semil-34', making it unsuitable to enhance apical dominance on the leading branch.
Heat Tolerance of Annual Cultivars in Zone 8
Authors: Quinn D.M. , Behe B.K. , Kessler J.R. , Bannon J.S.
Published: February 2019

In the summer of 1995 and 1996, 245 and 400 annual plant cultivars were evaluated for heat tolerance and landscape performance. Nine transplants of each cultivar were installed in raised beds amended with controlled-release fertilizer as per soil analysis recommendations, under full-sun and overhead irrigation, at the E.V. Smith Research Center in Shorter, Ala. (lat. 32° 30′ N, long. 85° 40′ W). No mainte-nance, with the exception of one midseason pruning of petunia, was performed on any of the cultivars. Catharanthus roseus 'Blush Cooler' was the best performer in 1995 with a mean rating of 4.1 (of 5.0). Salvia farinacea `Victoria Blue' and Petunia ×milliflora `Fantasy Pink' performed well, with a mean rating of 3.5. In 1996, the cultivar with the highest mean rating was Gomphrena globosa `Lavender Lady' (4.1). Second highest was G. globosa `Strawberry Fields' (4.0). Other cultivars that performed well in 1996 and had high mean ratings were Verbena × speciosa `Imagination' (3.6) and Melampodium paludosium `Derby' and `Medallion' (3.5 and 3.5).
A Comparison of Recycled Paper as a Growth Substrate in Container Production of Azaleas
Authors: Craig Paula , Cole Janet C.
Published: February 2019

Wet Earth (WE) is a recycled paper product that may substitute for peat moss as a growth substrate. WE is available at various pH levels and may be formulated using: 1) paper production byproducts (WES), or 2) recycled corrugated cardboard (WEC). Use of WE by commercial growers would reduce demand for both landfill space and for slowly renewable resources such as peat and pine bark. Experiment objectives included: analyzing plant performance of azaleas (Rhododendron obtusum `Hino Crimson') in WE-based growth substrates at pH 3.4 and pH 6.6 and in peat-based growth substrates (Trial pH), 2) analyzing plant performance of WES, WEC, and peat moss-based growth substrates (Trial SC), and 3) determining changes, if any, in substrate physical properties from planting to harvest. Shadehouse experiments were conducted in summer of 1996. Ratios of pine bark to WE tested were 100% pine bark, 1:3, 1:1, 3: l, and 100% WE by volume. Plant heights, widths, and visual quality ratings were obtained monthly throughout the 16-week experiment. Leaf, shoot, and root dry weights and leaf nitrogen concentration were determined at harvest. Changes in volume, bulk density, porosity, and air space were also measured. Plants performed poorly in WES, pH 3.4, with mortality exceeding 90%. Peat and WEC yielded similar (and best) results. Optimum plant performance for all substrates occurred in 1: 3 and 1: 1 (WE: pine bark) mixes. At concentrations over 50%, increases in bulk density and reductions in volume and percent air space in WE substrates were severe enough to negatively impact root growth and plant quality.
The Effect of Mulch Type and Fertilizer Placement on Marigold (Tagetes erecta `Hybrid Gold') Growth in Landscape Plantings
Authors: Mirabello R.M. , Einert A.E. , Klingaman G.L.
Published: February 2019

The objective of this study was to examine the influence of mulch material and fertilizer application method on nutrient availability in a landscape situation. Beds containing four mulch materials (pine bark, cypress pulp, pine straw, and cottonseed hulls) and three fertilizer application methods (granule, liquid, and time release) were established. Fertilizer placement included application either above or below the mulch horizon. Beds with and without mulch cover and no fertilization were established as controls. Marigolds, Tagetes erecta `Hybrid Gold', were planted within the beds. Plants in unmulched or fertilized control beds had greater dry weights than plants in beds with mulch alone. Only plants grown in the cottonseed hull control demonstrated a slight improvement and cottonseed hulls demonstrated the best plant performance overall. The greater nitrogen content of cottonseed hulls may influence less immobilization of nitrogen in the soil solution during decomposition and reduce competition for nutrients between microorganisms and plants. Fertilization improved plant growth in all treatments except pine bark. Beds using pine bark showed significant reduction in plant dry matter accumulation. Potential toxicity or changes in soil chemistry by pine bark may have influenced these results and will be examined in further experiments. Fertilizer placement had no effect on plant growth.
Influence of Seed Treatments on Germination and Initial Growth of Ornamental Palms
Authors: Morales-Payan Jose P. , Santos Bielinski M.
Published: February 2019

Experiments were conducted in the Dominican Republic to determine the effect of physical and chemical treatments on the germination of the ornamental palms Roystonea hispaniolana Bailey (Royal palm), Acrocomia quisqueyana Bailey (Corozo palm), Sabal umbraculifera Mart (Cana palm), Phoenix canariensis (Canary Islands date palm), Veitchia merrillii (Becc) Bailey (Manila palm), Chrysalidocarpus lutescens Wendl (Areca palm), and Caryota urens (Fishtail palm). Treatments were seed immersion in water or gibberellic acid 3 (GA3) solution for 72 hours, immersion in concentrated nitric acid for 5 minutes, or cracking of the seed coat. Rate and percentage of emergence 90 days after treatment were measured. The best results for Roystonea, Phoenix, Veitchia, Caryota, and Chrysalidocarpus were obtained soaking the seeds in water or a 200-ppm gibberellic acid solution. Nitric acid and seed coat cracking significantly reduced the germination percentage in all the species, except Acrocomia guisqueyana and Sabal umbraculifera. Seeds of Acrocomia did not germinate as a response to any of the treatments tested. Sabal seeds germinated only after coat cracking or nitric acid treatment.
Effect of Cropping System on Residual Soil P from Poultry Litter Application
Authors: Baker M.L. , Earhart D.R. , Haby V.A.
Published: February 2019

When poultry litter (PL) is applied to meet the nitrogen (N) needed for plant growth, phosphorus (P) can accumulate, leading to non-point source pollution of surface water. This study was conducted at Overton, Texas on a Bowie fine sandy loam (fine-loamy, siliceous, thermic, Plinthic Paleudults) to investigate the use of warm- and cool-season forage legumes in rotational cropping systems to remove excess P. Cropping systems were: spring legume—fall vegetable (SL-FV), spring vegetable—fall legume (SV-FL), and spring vegetable-fall vegetable (SV-FV). Warm- and cool-season legumes were Iron and Clay cowpea and crimson clover, respectively. Poultry litter rates were 0, 1X, 2X, 4X, and commercial blend (CB) as subplots. Fertility treatments were applied to vegetable plots only. The crop, IX PL and CB rate for each season were: spring 1995—watermelon, 2.2 t·ha-1, 48.8N—12.2P—28K kg·ha-1; fall 1995—turnip, 8.3 t·ha-1, 89.6N—24.4P—28K kg·ha-1; spring 1996—tomato, 6.7 t·ha-1, 100.9N—17.1P—78.5K kg·ha-1. Soil P increased at all depths sampled (0-15, 15-30, and 30-45 cm) as PL rate increased. Residual P from CB was equal to the control. Through spring 1996, soil P concentration in the surface 0-15 cm was increased by all systems. System SV-FL reduced P accumulation by 35.6 mg·kg-1 when compared to SL-FV and 44.7 mg·kg-1 when compared to SV-FV. Residual P continued to increase as PL rate increased. Rate of increase was reduced by a system of SV-FL.
Conservation Tillage of Sweetpotato
Authors: Jett Lewis W. , Talbot Timothy P.
Published: February 2019

A cultural practice that can modify and conserve the soil environment is needed in sweetpotato [Ipomoea batatas (L.) Lam.] production. The objective of this research was to evaluate conventional and conservation tillage of sweetpotato with four cover crop species (fallow, ryegrass, rye, and wheat). The cover crops were seeded in late Oct. 1995, and the sweetpotato transplants (`Beauregard') were transplanted at two dates the following spring (May and June). Conservation tillage significantly lowered soil temperature (10 cm depth) during storage root initiation and development. Moreover, each cover crop significantly reduced weed emergence and soil erosion. The ryegrass conservation tillage treatment significantly increased marketable yield of sweetpotato in the first planting date, while rye and wheat performed equally well in the second planting date. In the second planting date, white grub (Phyllophaga ephilida Say) injury to storage roots was significantly higher in the conservation tillage treatments. However, conservation tillage seems to be a viable alternative to the conventional method of sweetpotato production.
Tolerance of `Sunrise' Papaya to Postemergence Herbicides
Authors: Santos Bielinski M. , Morales-Payan Jose P.
Published: February 2019

Trials were conducted under controlled conditions to determine the tolerance of young papaya plants (15 cm tall) to postemergence herbicides. Herbicides used were paraquat (1.68 Kg ai/Ha), MSMA (2.24 Kg ai/Ha), 2,4-D (4.26 Kg ai/Ha), bromoxynil (0.28 Kg ai/Ha), cyanazine (1.12 Kg ai/Ha), dimethenamid (1.12 Kg ai/Ha), endothal (0.56 Kg ai/Ha), imazameth (0.067 Kg ai/Ha), imazethapyr (0.028 Kg ai/Ha) lactofen (0.12 Kg ai/Ha), oxyfluorfen (0.03 Kg ai/Ha), acifluorfen (0.28 Kg ai/Ha), atrazine (2.24 Kg ai/Ha), and bentazon (1.12 Kg ai/Ha) as well as the untreated control. Atrazine, bentazon, cyanazine, imazemeth, imazethapyr, and dimethenamid did not cause phytotoxicity at the rates used and were equal to the untreated control. Other herbicides caused severe injuries followed by total death at 10 days after treatment.
Sweetpotato Plant Bed Fertilization
Authors: Main Jeff L. , Thompson Paul G. , Burdine William , Sloan R. Crofton
Published: February 2019

Seventeen plant bed fertilizer treatments including different rates of N, P, and K were evaluated for the effect on plant production and sweetpotato yield. `Beauregard' storage roots were bedded. Treatments were 0, 40, 80 lb N/ac; 0, 80, 160 lb P/ac; or 0, 75, 150, and 300 lb K/ac. Each nutrient was evaluated in a separate trial. After the first cutting, half of the N treatments and all P and K treatments had 40 lb N/ac top-dressed on the beds. For the first cutting the high rate of N (80 lb/ac) had a higher green weight than the low rate of 0 lb/ac. There wer no other differences found in the first or second cuttings for plant production or yield. Plant bed fertilization also had no effect on transplant survival.
Multiple Defense Functions of Sweetpotato Resin Glycosides
Authors: Peterson J.K. , Harrison H.F.
Published: February 2019

Sweetpotato resin glycosides were purified by HPLC methods. Most allelopathic potential could be explained by these compounds. Fifty percent inhibition (I50) of seed germination was obtained for redroot pigweed at 160 ppm, for velvetleaf at 13 ppm and for prosomillet at 11 ppm. Seed of the congeneric species I. purpurea was not sensitive. Growth of yellow nutsedge was drastically reduced, the I50 for shoot growth was 30 ppm, for number of roots 36 ppm, and for total root length 19 ppm. The glycosides accounted for approximately half of the total fungicidal activity of all extract fractions when tested on Fusarium oxysporum pv. batatae. At 2 mg per ml, the glycosides inhibited hyphal growth by 31%. This concentration is less than 10% of the glycoside concentration in dry periderm tissue of `Regal'. The purified glycosides were incorporated into a meridic diet for diamondback moth larvae. All observed antibiosis was caused by the glycosides; the LD50 was 7.2 mg per ml diet. At that concentration the surviving larvae showed a weight decrease of 46%.
Reaction of Cowpea Cultivars, Breeding Lines, and PIs to Bacterial Blight
Authors: Buckley Blair , Clark Christopher A.
Published: February 2019

Bacterial blight, incited by Xanthomonas axonopodis pv. vignicola, is a major disease of cowpea. Strong resistance has not been reported in commercial cultivars. Many cultivars released within the last ten years have not been previously screened. Thirty-eight cowpea cultivars, 60 breeding lines, and 25 PIs were screened for reaction to bacterial blight in tests conducted in a greenhouse. Inoculum was adjusted turbidimetrically (OD620nm = 0.1) to approximately 108 cfu/ml. Seedling plants were inoculated by either leaf infiltration or stem puncture methods. Ratings were on a 1-6 scale in which 1 = no symptoms, 2 = localized lesions at site of inoculation, 3 = lesions spreading slightly near site of inoculation, 4 = any symptoms on systemically infected leaves or stems, 5 = extensive wilting and/or stem collapse, 6 = dead plant. All cultivars were susceptible to the pathogen. Cream-type cultivars Bettergreen, Tender Cream, Zipper Cream, Carolina Cream, and Mississippi Cream were among the most susceptible. Breeding lines MN13, MN150, TX57069-11, TX 58048-2000, and TX 59069-11 produced hypersensitive reactions in response to leaf infiltration inoculation. However, the three TX lines were rated susceptible when inoculated by stem puncture. Eighteen PIs (including PI293467, PI293521, PI293525, PI293567, and PI293571) were highly resistant to bacterial blight.
Smooth Amaranth Interference with Watermelon and Muskmelon Production
Authors: Terry Ernest R. , Stall William M. , Shilling Donn G. , Bewick Thomas A. , Kostewicz Steven R.
Published: February 2019

Studies were conducted to determine the critical period of smooth amaranth interference in watermelon (Citrullus lunatus L.) and muskmelon (Cucumis melo L. var. reticulatus). Best-fit linear or exponential regression models were used to predict the maximum period of competition and the minimum weed-free period for 10% yield loss. The maximum period of competition and minimum weed-free period was 0.50 and 2.97 weeks after watermelon emergence, respectively, and 1.0 and 3.9 weeks after muskmelon emergence, respectively. The critical periods of smooth amaranth interference for the crops were between those intervals. In both crops, late emerging smooth amaranth had little effect on total yield. Smooth amaranth introduced at crop emergence reduced total yield. The effect of competition on yield components, i.e., fruit number per hectare and fruit mass, varied by crop. Muskmelon fruit count was more sensitive to smooth amaranth competition than was watermelon fruit count. Conversely, mass per fruit of muskmelon was less sensitive to this competition than was mass per fruit of watermelon.
The Pepino (Solarium muricatum Ait.): An Alternative Crop for Areas Affected by Moderate Salinity
Authors: Ruiz Juan José , Nuez Fernando
Published: February 2019

Three clonal hybrids of pepino and their six parental clones were grown in a greenhouse at two salinity levels, 3 and 8 dS·m-1, and two K levels, 246 and 492 mg·L-1. Nearly all the clones maintained high yields even at 8 dS·m-1. Hybrids were highly productive and were more salt-tolerant than their parental clones. In the majority of clones, salinity shortened mean time to harvest by more than 10 days. Salinity also increased organoleptic quality of pepino fruit, mainly due to the increase in soluble solids concentration (SSC). Potassium had little effect on yield and on organoleptic characteristics, although the yield of the less-productive clones appears to be affected by the high level of K (492 mg·L-1). Our results suggest that the pepino could be an alternative crop in areas where only moderately saline water is available, since it is possible to maintain crop productivity while improving its organoleptic quality—the latter being a key issue for its acceptability in European and U.S. markets.
Winter Cover Crops and Nitrogen Management in Sweet Corn and Broccoli Rotations
Authors: Burket John Z. , Hemphill Delbert D. , Dick Richard P.
Published: February 2019

Cover crops hold potential to improve soil quality, to recover residual fertilizer N in the soil after a summer crop that otherwise might leach to the groundwater, and to be a source of N for subsequently planted vegetable crops. The objective of this 5-year study was to determine the N uptake by winter cover crops and its effect on summer vegetable productivity. Winter cover crops [red clover (Trifolium pratense L.), cereal rye (Secale cereale L. var. Wheeler), a cereal rye/Austrian winter pea (Pisum sativum L.) mix, or a winter fallow control] were in a rotation with alternate years of sweet corn (Zea mays L. cv. Jubilee) and broccoli (Brassica oleracea L. Botrytis Group cv. Gem). The subplots were N rate (zero, intermediate, and as recommended for vegetable crop). Summer relay plantings of red clover or cereal rye were also used to gain early establishment of the cover crop. Cereal rye cover crops recovered residual fertilizer N at an average of 40 kg·ha-1 following the recommended N rates, but after 5 years of cropping, there was no evidence that the N conserved by the cereal rye cover crop would permit a reduction in inorganic N inputs to maintain yields. Intermediate rates of N applied to summer crops in combination with winter cover crops containing legumes produced vegetable yields similar to those with recommended rates of N in combination with winter fallow or cereal rye cover crops. There was a consistent trend (P < 0.12) for cereal rye cover crops to cause a small decrease in broccoli yields as compared to winter fallow.
Growth and Nutrition of Geraniums Grown in Media Developed From Waste Tire Components
Authors: Newman Steven E. , Panter Karen L. , Roll Michael J. , Miller Robert O.
Published: February 2019

Two cultivars of zonal geraniums (Pelargonium ×hortorum Bailey), `Danielle' and `Kim', were grown in media containing three grind sizes of rubber (2.4, 6, or 10 mm) and fiber from the fabric belting processed from waste tires in three proportions: 1 rubber or fiber: 1 peat; 1 rubber or fiber: 1 vermiculite: 2 peat; and 2 rubber or fiber: 1 vermiculite: 1 peat (by volume). Two control media were also included: 1 vermiculite: 1 peat, and 1 rockwool: 1 peat (by volume). Geranium plants were grown in media containing up to 25% waste tire products along with traditional medium components without reducing plant quality. Plant growth was best and flower count was highest in the vermiculite and peat medium, plants were smallest and flower count was lowest in media containing the rubber grinds at 2.4 or 6 mm, making up 50% of the media. The medium 1 rubber: 1 vermiculite: 2 peat, regardless of grind or fiber, produced plants equal to the rockwool and peat moss medium. All plants grown in media containing rubber by-products had elevated Zn and Cu in the foliage; however, Zn and Cu were highest in media containing 50% rubber. Foliar P: Zn ratios were less for plants grown in media containing 50% rubber and also were lower in plants grown in media with smaller rubber grind sizes.
Raised Beds and Microirrigation Influence Peach Production
Authors: Funt Richard C. , Schmittgen Mark C. , Schwab Glen O.
Published: February 2019

The performance of peach trees [Prunus persica (L.) Batsch cv. Redhaven/Siberian C.] on raised beds as compared to the conventional flat (unraised) orchard floor surface was evaluated from 1982 to 1991. The raised bed was similar to the flat bed in cation exchange capacity (CEC), Ca, P, K, Mg, B, and Zn soil levels in the 0-15 cm depth. Microirrigation, using two 3.7 L.h-1 emitters per tree vs. no irrigation, was applied to trees planted in a north-south orientation on a silt loam, noncalcareous soil. Raised beds increased trunk cross-sectional area (TCA) and yield-efficiency over 5 years. Irrigation increased fruit mass mostly in years of highest evaporation. Significant year to year variations occurred in yield, fruit mass, TCA and yield efficiency. There were significant bed × year interactions for yield and TCA. Irrigation increased leaf boron content regardless of bed type. Leaf potassium was higher in flat beds. Nonirrigated trees had the lowest tree survival on the flat bed, but the opposite was true on the raised bed.
Zinnia Seed Harvest Time Affects Germination and Plant Growth
Authors: Miyajima Daiichiro
Published: February 2019

Seeds of `Kumamotonokagayaki'(Kk), `Goldenball' (Gb), and `Purple Gem' (PG) (Zinnia violacea Cav.) were harvested at various stages of maturity and subsequent seed and plant performance were evaluated. The largest increase in ovule or embryo length and width occurred from 0 to 10 days after pollination (DAP). The seed weight was unchanged after 23, 25, and 30 DAP for Kk, Gb, and PG, respectively. The pericarp color was completely green from seeds harvested 20 DAP, while the seeds harvested from 30 to 35 DAP contained a mixture of green and brown seeds. Pericarp color change from green to brown was not a reliable index to harvest seeds. The percentage germination increased from seeds harvested from 10 to 19 DAP for all cultivars. From 20 to 40 DAP, germination was unaffected and >90%, while the rate of germination as measured by days to visible germination decreased slightly. Seeds harvested 20 to 40 DAP produced plants with similar growth and quality characteristics. Considering a 20- to 30-day difference between the first and last floret to open in a capitulum, capitula should be harvested 50 days after anthesis for good seed quality and to prevent shattering.
A Micropipette Method for Collecting Vacuolar Sap of Intact Tannin and Parenchyma Cells in Persimmon
Authors: Yonemori Keizo , Oshida Masayoshi , Fukuda Fumio , Sugiura Akira
Published: February 2019

A method for collecting the vacuolar contents of intact tannin and parenchyma cells of persimmon (Diospyros kaki Thunb.) fruit using a micropipette was developed. Thin sections of the mesocarp tissue from mature persimmon fruit, `Miyazaki-mukaku' and `Hiratanenashi', were placed on a glass slide. Using a micromanipulator and an inverted microscope, a micropipette was inserted into a vacuole and its contents were withdrawn. A 5-nL sample of vacuole sap was collected per tannin cell from `Hiratanenashi' and 7 nL from `Miyazaki-mukaku', whereas only 2 nL was withdrawn from adjacent parenchyma cells. Analyses of the vacuolar sap revealed that the tannin cells of both cultivars contained 10% to 12% (m/v) of tannin as (+)-catechin equivalents and 10% to 13% (m/v) of soluble sugars, whereas the parenchyma cells contained trace amounts of tannins and ≈20% of soluble sugars. Tannin cells contain only a slight amount of sucrose, in contrast to a relatively large amount in parenchyma cells.
Field Resistance of California Strawberries to Verticillium dahliae at Three Conidial Inoculum Concentrations
Authors: Shaw Douglas V. , Gubler W. Douglas , Hansen John
Published: February 2019

Runner plants from strawberry (Fragaria ×ananassa Duch.) genotypes previously identified as relatively susceptible, intermediate, and resistant to wilt caused by Verticillium dahliae Kreb. were inoculated with a conidial suspension containing a mixture of five isolates of V. dahliae at 104, 105, and 106 conidia/mL. Disease symptoms were scored as the number of dead or severely stunted plants per plot, or on the basis of a subjective phenotypic resistance score assigned to each plot on eight dates during the spring after planting. Overall disease symptoms increased with inoculum concentration; resistance scores for all genotypes were 4.8, 3.7, and 3.2, and the percentages of plants stunted or dead were 6.8, 32.6, and 44.9 for the three conidial concentrations, respectively. The relative resistance categories were separable at concentrations of 106 and 105, whereas no separation was obtained at 104 conidia/mL. Genotypes originally classified as intermediate in resistance performed more like susceptible types at the highest conidial concentration. Significant resistance category × conidial concentration level interactions were detected for resistance score but not for the number of dead or severely stunted plants per plot. Regression coefficients for resistance score and percentage of stunting on conidial concentrations were statistically significant only for susceptible and intermediate genotypes. Some stunting was detected within all resistance categories at the highest conidial concentration, and the practical value of the resistance developed to date will depend ultimately on realistic field inoculum levels.
Increased Suberin Accumulation in Peach × Almond Hybrids
Authors: Biggs A.R. , Scorza R.
Published: February 2019

Suberin accumulation in mechanically wounded bark tissue was determined fluorimetrically in greenhouse-grown peach [Prunus persica (L.) Batsch] and F2 progeny from peach × almond [P. amygdalus (Mill.) DA. Webb] hybrids. In general, suberin accumulation following wounding was significantly greater for progeny from almond-type than for peach-type hybrids. Hybrids from parents with almond tree type combined with peach fruit type accumulated the highest suberin levels. These data may partially explain the differences observed among peach and peach × almond hybrids in relative susceptibility to Leucostoma canker [Leucostoma persoonii Hohn. and L. cincta (Fr.) Hohn.] and injury caused by lesser peachtree borer. The association of higher suberin accumulation with specific phenotypic characteristics could simplify the selection of desirable seedlings in a breeding program that includes canker resistance as an objective.
Variation of Cold Tolerance among Open-pollinated Sweet Corn Cultivars
Authors: Hotchkiss J.R. , Revilla P. , Tracy W.F.
Published: February 2019

Cold tolerance useful for sweet corn improvement may be present in open-pollinated (OP) cultivars. Cold tolerance in sweet corn is the ability to germinate, emerge, and grow under low temperatures. The cold tolerance of 35 open-pollinated sweet corn populations and controls was measured by growing the entries under 14 °C day/10 °C night in growth chambers. The same entries were grown under warm (24 ± 2 °C) conditions in a greenhouse. Traits measured included percent and time to emergence, seedling color, and seedling root and shoot dry mass. Respective repeatability estimates calculated from mean squares were 0.08, 0.33, 0.33, 0.50, and 0.60 for these traits. Entries were ranked separately in each environment based on their performance using a rank-summation index. Differences in cold tolerance existed among the entries. Emergence ranged from 75% to 100% among the entries, with a mean of 90.9%. Time to emergence ranged from 16.2 to 21.9 d, with a mean of 18.2 d. Root and shoot mass ranged from 0.07 to 0.27 g/plot and 0.07 to 0.24 g/plot, respectively. Correlations among the traits measured were favorable, permitting simultaneous improvement. The rankings between the warm and cold environments were significantly correlated (r = 0.67***), indicating that some entries that performed well under low temperatures also performed well under warm conditions.
Growth of Dieffenbachia maculata `Camille' in Growing Media Containing Sphagnum Peat or Coconut Coir Dust
Authors: Stamps Robert H. , Evans Michael R.
Published: February 2019

A comparison was made of Canadian sphagnum peat (SP) and Philippine coconut (Cocos nucifera L.) coir dust (CD) as growing media components for Dieffenbachia maculata [(Lodd.) G. Don] `Camille' greenhouse production. Three soilless foliage plant growing mixes [Cornell, Hybrid, Univ. of Florida #2 (UF-2)] were prepared using either SP or CD and pine bark (PB), vermiculite (V), and/or perlite (P) in the following ratios (percent by volume): Cornell = 50 CD or SP:25 V:25 P, Hybrid = 40 CD or SP:30 V:30 PB, UF-2 = 50 CD or SP:50 PB. Initial CI concentrations and electrical conductivities were higher for CD-containing media (CDM) than SP-containing media (SPM). At termination, Ca, Mg, and NO3-N concentrations were higher for SPM than CDM. Bulk densities were lower for CDM than SPM for one medium, but not for the others. Water-filled pore space (W-FPS) and water-holding capacity (W-HC) were larger and air-filled pore space (A-FPS) generally was smaller for CDM than SPM. Cornell had the highest W-FPS and W-HC, lowest A-FPS and percentage of large particles, and produced the highest grade and heaviest plants. Plant top grades, fresh mass and overall mass, but not root grades and mass, were higher for CDM than SPM. Plant mass was positively correlated with initial medium W-HC but not with A-FPS. Lower K in mix UF-2 compared to the mixes containing vermiculite may have been partly responsible for the lesser growth in that mix.
Growth and Yield of Eggplants Grafted by a Newly Developed Robot
Authors: Oda Masayuki , Okada Kunihiko , Sasaki Hidekazu , Akazawa Shigeki , Sei Masahiro
Published: February 2019

Eggplant (Solanum melongena L.) at the two-leaf stage were grafted on scarlet eggplant (Solanum integrifolium Poir.) by hand or a newly developed robot. The scion and rootstock were fixed with an elastic tube for hand grafting or with an adhesive and a hardener for robotic grafting. After acclimatization, the grafted plants were planted at the three- or 11-leaf stage in a glasshouse. Plants grafted by the robot showed a higher percentage of survival, and attained the three- and 11-leaf stages 8 days earlier on average than those grafted by hand. Stems were longer, and shoot fresh mass and fruit yield of plants were higher for the three-leaf-than for the 11-leaf-stage planting, irrespective of the grafting method. Such vigorous growth and high yield by robotic grafting were absent for the 11-leaf-stage planting but obvious for the three-leaf-stage planting.
Cold Treatment and Forcing Temperature Influence Flowering of Campanula carpatica `Blue Clips'
Authors: Whitman Catherine M. , Heins Royal D. , Cameron Arthur C. , Carlson William H.
Published: February 2019

The influence of cold treatments on flowering in Campanula carpatica Jacq. `Blue Clips' was determined. Plants with 10 to 12 nodes (P1) and 12 to 16 nodes (P2), in 128-cell (10-mL cell volume) and 50-cell (85-mL cell volume) trays, respectively, were stored at 5 °C for 0, 2, 4, 6, 8, 10, 12, or 14 weeks under a 9-hour photoperiod. They then were transplanted and forced in a 20 °C greenhouse under a 9-hour photoperiod with a 4-hour night interruption (NI) (2200 to 0200 hr). Time to visible bud and to flowering in P1 decreased slightly as the duration of cold treatment increased. Flowering was hastened by ≈10 days after 14 weeks at 5 °C. Cold treatments had no significant effect on time to visible bud or flower in P2. The number of flower buds on P1 did not change significantly in response to cold treatments, while flower bud count on P2 increased by up to 60% as duration of cold treatments increased. Final height at flowering of both ages decreased 10% to 20% with increasing duration of cold exposure. To determine the relationship between forcing temperature and time to flower, three plant sizes were forced under a 9-hour photoperiod with a 4-hour NI (2200 to 0200 hr) at 15, 18, 21, 24, or 27 °C. Plants flowered more quickly at higher temperatures, but the number and diameter of flowers were reduced. Days to visible bud and flowering were converted to rates, and base temperature (Tb) and thermal time to flowering (degree-days) were calculated. Average Tb for forcing to visible bud stage was 2.1 °C; for forcing to flower, 0.0 °C. Calculated degree-days to visible bud were 455; to flower, 909.
Growth of Pelargonium ×hortorum and Euphorbia pulcherrima in Rubber-containing Substrates
Authors: Evans Michael R. , Harkess Richard L.
Published: February 2019

Geranium (Pelargonium ×hortorum L.H. Bailey) `Freckles' and poinsettia (Euphorbia pulcherrima Willd. ex Klotzch) `Freedom' were grown in six peat and shredded-rubber substrates formulated to contain 75:25:0, 50:50:0, 25:75:0, 75:0:25, 50:0:50, 25:0:75 sphagnum peat: fine-grade rubber: coarse-grade rubber (by volume). Additionally, plants were grown in a 50 peat: 30 perlite: 20 loam (by volume) control substrate. Shredded rubber-containing substrates had higher bulk densities, lower total pore space, and higher total solids than the control substrate. Fine rubber-containing substrates had lower air-filled pore space (AFP) and lower water-holding capacities (WHC) than the control substrate. Substrates containing 25% coarse rubber had lower AFP and WHC than the control, but substrates containing 50% and 75% coarse shredded rubber had higher AFP and lower WHC than the control. Shredded rubber-containing substrates had significantly higher levels of Zn than the control substrate. Plants grown in rubber-containing substrates had tissue Zn levels significantly higher than the control and at levels reported to be phytotoxic in other species. Geraniums grown in rubber-containing substrates had lower root and shoot fresh mass, were shorter, and had fewer axillary branches than those grown in the control substrate. Poinsettia plants grown in rubber-containing substrates were shorter, had lower shoot fresh mass, fewer bracts, and lower bract area as compared to plants grown in the control substrate.