bluuebunny/crossref_metadata_2025 huggingface dataset:
Cold Injury of Southern Blueberries as a Function of Germplasm and Season of Flower Bud Development
Authors: Patten Kim , Neuendorff Elizabeth , Nimr Gary , Clark John R. , Fernandez Gina
Published: February 2019

The relative tolerance of flower buds and flowers of southern highbush blueberry (Vaccinium spp.) to cold damage was compared to rabbiteye (Vaccinium ashei Reade) and highbush blueberry (Vaccinium corymbosum L.). For similar stages of floral bud development, southern highbush and highbush cultivars had less winter freeze and spring frost damage than rabbiteye cultivars. Cold damage increased linearly with stage of flower bud development. Small fruit were more sensitive to frost damage than open flowers. Rabbiteye blueberry flower buds formed during the fall growth flush were more hardy than buds formed during the spring growth flush, regardless of cultivar or stage of development.
Yield Response of Watermelon and Muskmelon to L-Tryptophan Applied to Soil
Authors: Frankenberger W.T. , Arshad M.
Published: February 2019

This study was conducted to determine the influence of l-tryptophan (l-TRP) applied to soil on the yield of two watermelon (Citrullus Lanatus L.) and one muskmelon (Cucumis melo L.) cultivars. Experiments were established in which l-TRP was applied to seedlings as a soil drench in the glasshouse ranging from 6 × 10-5 to 60 mg·kg-1 soil; the seedlings were transplanted into the field 2 weeks later. The application of l-TRP enhanced the cumulative weight of the melons 58% ('Royal Sweet' watermelon), 80% (`Royal Windsor' watermelon), and 42% (`Top Score' muskmelon) over their respective controls: the average weight per fruit was increased up to 43% for watermelon and 36% for muskmelon. No increase in yield was observed when l-TRP was applied to the seedlings directly in the field, but only when added in contained systems 2 weeks before transplanting into the field. The increase in yield was due to a physiological response rather `than a nutritional effect because of the low l-TRP concentrations applied.
Using X-ray-computed Tomography to Nondestructively Determine Maturity of Green Tomatoes
Authors: Brecht Jeffrey K. , Shewfelt Robert L. , Garner Joseph C. , Tollner E.W.
Published: February 2019

Cross-sectional X-ray-computed tomography (X-ray CT) images through the equator of tomato fruit (Lycopersicon esculentum Mill., cv. Sunny) ranging in maturity from immature (Ml) to advanced mature green (M4) revealed localized differences in X-ray absorption related to the formation of locular gel during maturation of the fruit. While maturity stage was poorly correlated with average X-ray absorbance and standard deviation or with average fruit density and water content, significant relationships' existed between maturity stage “and the number of image pixels with absorbance values >10 (Ml vs. M2 vs. M3) or 20 (M3 vs. M4) Hounsfield units. Using discriminant analysis, a relationship was developed that correctly identified the maturity class of 77% of the fruit and placed 96% of the tomatoes into the correct or an adjacent class.
Roles of Auxin and Ethylene in Adventitious Root Formation by a Flood-resistant Tomato Genotype
Authors: McNamara Steven T. , Mitchell Cary A.
Published: February 2019

The relative contributions of auxin and ethylene (C2H4) in stimulating the initiation of adventitious root primordia (ARP) and their subsequent development into adventitious roots (ARs) by flooded tomato (Lycopersicon esculentum Mill. PI 406966) seedlings were evaluated using TIBA and STS. Flooded plants treated with STS (F + STS) produced ≈ 40% as many emerged ARs as plants that were flooded only (F). Only 7% of the ARP initiated by F + STS plants developed enough to emerge through the epidermis by 120 hours of treatment compared with 95% emerged for F plants. A band of TIBA applied below the lowest leaves of flooded plants (F + TIBA) virtually eliminated AR formation. Plants with two or four leaves below the TIBA band produced 16- and 35-fold more ARs, respectively, than those with no leaves below the TIBA band. Relative to nonflooded (NF) plants, F + STS plants exhibited a nearly 40-fold increase in C2H4 evolution, while F and F + TIBA plants exhibited about a 5-fold increase in C2H4 production. These results suggest that auxin accumulation at or above the floodline is essential for ARP initiation and that auxin action is not mediated through C2H4. Ethylene may be required for elongation of flood-induced ARP leading to their emergence as ARs. Chemical names used: 2,3.5 -triiodobenzoic acid (TIBA): silver thiosulphate (STS).
Interspecific Responses of Marigold to Manganese as Influenced by Nitrogen Source
Authors: Reddy K.S. , Mills H.A.
Published: February 2019

Responses of two hydroponically grown marigold species, Tagetes erects L. `pumpkin Crush' and T. patula L. `Janie Yellow', to Mn concentrations of 0.5 mg·liter-1 or 10 mg·liter-1 with KNO3 and Ca(NO3)2 (NO3 source) or NH4N O3 as the N source were investigated. In both species, Mn uptake was enhanced with the NO3 source while reduced with NH4NO3. With Mn supplied at 0.5 mg·liter-1 and NO3 as the N source, T. erects absorbed twice the Mn per gram of dry matter as T. patula. T. erecta accumulated higher concentration of Mn in the shoot than in the root irrespective of the N source. T. patula accumulated higher concentration of Mn in the roots with the NO3 source while NH4NO3 shifted the Mn accumulation to the shoot. Growth of both species was suppressed with 10 mg Mn/liter and the suppression was greater with the NO3 source than with the NH4NO3. These results indicate an interspecific response to Mn concentration as well as an N source influence on the uptake of Mn in marigold grown under hydroponic conditions.
Silver Thiosulfate Application Influences Rooting and Budbreak of `Royalty' Rose Cuttings
Authors: Sun Wen-Quan , Bassuk Nina L.
Published: February 2019

The effects of silver thiosulfate (STS) on stored and freshly made cuttings of `Royalty' rose (Rosa hybrids) were examined in relation to rooting and subsequent budbreak. STS pretreatment at 0.5 mm during storage stimulated budbreak but decreased the percentage of cuttings that rooted and the number of roots. IBA at 4.9 to 9.8 mm inhibited budbreak but this effect was partially reversed by STS. Spraying the cuttings with 1.0 mm STS once daily during the first 5 days of the rooting period also reduced rooting but prevented IBA-induced leaf senescence. Ethephon and spermine, each applied at 0.5 mm before rooting, had no effect on rooting or budbreak. Chemical names used: (2-chloroethyl)-phosphonic acid (ethephon); indole butyric acid (IBA); N,N'-bis(3-aminopropyl) -l,4-buanediamine (spermine).
Detection of Tomato Ringspot Virus in Nectarine Trees Using ELISA and Transcribed RNA Probes
Authors: Powell C.A. , Hadidi A. , Halbrendt J.M.
Published: February 2019

The ability of 32P-labeled transcribed cRNA probes to detect tomato ringspot virus (TmRSV) RNA in nucleic acid extracts from roots, bark, and leaves of nectarine (Prunus persica [L.] Batsch) trees with the Prunus stem-pitting disease was assessed and compared with detection of TmRSV antigen by enzyme-linked immunosorbent assay (ELISA) in the same tissues. Neither TmRSV-specific nucleic acid nor antigen was detected in nectarine leaf tissue. ELISA detected TmRSV antigen in root extracts from 71% of the diseased trees, while dot hybridization detected virus-specific nucleic acid in 18% of the same samples. However, ELISA detected TmRSV antigen in only 47% of bark extracts; whereas TmRSV-specific nucleic acid was detected in 100% of the bark extracts from samples collected at or near the soil line. When nucleic acid extracts from bark were prepared from various locations on diseased trees and tested for TmRSV-specific nucleic acid by dot hybridization, there was an almost perfect correlation between the presence of stem-pitting symptoms and the detection of TmRSV nucleic acid. Detection of TmRSV RNA from the bark tissue of rootstock suckers from TmRSV-infected `Delicious'/MM.lO6 apple (Malus × domestica Borkh.) trees was unsuccessful using dot hybridization. The viral RNA, however, was usually detected in either leaf or root tissue of these same trees.
Postharvest Quality of Passion Fruit as Influenced by Harvest Time and Ethylene Treatment
Authors: Arjona Harvey E. , Matta Frank B.
Published: February 2019

Greenhouse-grown purple passion fruit (Passiflora edulis Sims) were harvested mature-green 55 or 60 days after anthesis (DAA) and stored for 10 days at 10C. After storage, half the fruit were treated with 10 μl ethylene/liter for 35 hours and then stored at 21C for 48 hours. Juice of treated and nontreated fruit was analyzed for comparison with juice of vine-ripened fruit (harvested 70 to 80 DAA). Sucrose concentration decreased and fructose and glucose concentrations increased after storage, regardless of ethylene treatment. Fruit harvested 55 or 60 DAA, with or without ethylene, had the same sugar and soluble solids concentrations and pH as vine-ripened fruit. Ethylene treatment enhanced surface purple pigmentation of fruit harvested mature-green.
Temperature of Broccoli Florets at Time of Packaging Influences Package Atmosphere and Quality
Authors: Forney Charles F. , Rij Roger E.
Published: February 2019

Warm (20C) or cold (3C) broccoli florets (Brassica oleracea L., Italica Group) were sealed in bags of two types of nonperforated flexible polyvinylchloride film, TPM 87 or RMF 61, and kept at 5C for 7 days. Temperature of the warm florets cooled to 5C in ≈ 8 hours. Warm broccoli had 40% to 50% more CO2 and 25% to 30% less O2 than cold broccoli in packages of both film types 6 hours after sealing. After 48 hours, however, concentrations of CO2 in bags of cold and warm broccoli had reached a steady state of ≈ 14.5% in TPM 87 bags and 6% in RMF 61 bags. Concentrations of O2 were more variable. After 48 hours, O2 concentrations were ≈ 2% to 4% in TPM 87 bags and 5% to 10% in RMF 61 bags. Initially, warm florets were rated lower for color, turgidity, and general appearance than initially cold ones after 7 days at 5C. Objectionable off-odors were formed from florets held in TPM 87 packages that had O2concentrations of <1.5%.
The Near Infrared Determination of Moisture in Whole Dates
Authors: Dull Gerald G. , Leffler Richard G. , Birth Gerald S. , Zaltzman Arthur , Schmilovitch Ze'ev
Published: February 2019

Whole dates (Phoenix dactylifera L.) were analyzed for moisture content using near infrared spectrophotometry in a direct transmittance geometry. In the calibration experiment using 72 samples, the correlation coefficient was 0.977 and the standard error of calibration (SEC) was 0.89%. When the calibration equation was used to predict the moisture in another set of 72 date samples, the standard error of performance (SEP) was 1.5%. When the method was used to sort these 72 dates into four industry-standard grades, 74% were correctly graded and 15% missed the grade by <1 SEC.
The Use of Zeatin to Initiate in Vitro Cultures of Vaccinium Species and Cultivars
Authors: Reed Barbara M. , Abdelnour-Esquivel Ana
Published: February 2019

Explants of mature pot-grown Vaccinium corybosum L. cultivars were tested for initiation of new shoots using two growing conditions and four cytokinin treatments. Initiation tests with 12 genotypes showed significantly higher rates of new shoot growth on modified woody plant (MWPM) medium with 4 mg zeatin/liter at 25C under low light intensity than on any other treatment. Explants at 25C in light with 10 or 15 mg 2iP/liter initiated at a moderate rate, but significantly lower rates were found for all controls and at 4C in darkness. To determine the utility of zeatin for initiation of diverse genotypes, 96 Vaccinium accessions from the National Clonal Germplasm Repository, representing 22 species and 44 cultivars, were screened using 25C and low light intensity. Initiation rates higher than 60% were achieved for 89 of 96 accessions tested. Chemical name used: N6-[2-isopentenyl] adenine (2iP), 6-[4-hydroxy-3-methylbut-2-enylamino]purine (zeatin).
Market Segmentation of Pennslyvania Floral Consumers by Purchase Volume and Primary Retail Outlet
Authors: Behe Bridget K. , Wolnick Dennis J.
Published: February 2019

Market segmentation is an, efficient method of defining consumer groups to develop new markets. The purpose of this research was to determine the viability of market segmentation strategies based on volume and location of purchase. A sample of 401 Pennsylvania floral consumers was divided into groups based on the number and the primary location of floral purchases. Two discriminant analyses were conducted to determine differences between market segments. Heavy floral consumers exhibited a higher level of floral knowledge, purchased more floral products for themselves and from nonflorist retailers, and had higher incomes than light or medium floral users. Florist customers purchased fresh flowers more frequently, bought more floral gifts, and spent a higher amount per purchase than supermarket customers. Segmentation based on volume of purchase and primary retail location are both viable alternatives for market development strategies for floral consumers.
Modification of Yield and Chlorophyll Content in Leaf Lettuce by HPS Radiation and Nitrogen Treatments
Authors: Mitchell Cary A. , Leakakos Tina , Ford Tameria L.
Published: February 2019

This study evaluated the potential of high photosynthetic photon flux (PPF) from high-pressure sodium (HPS) lamps, alone or in combination with metal halide (MH) plus quartz iodide (QI) incandescent lamps, to support lettuce growth, with or without N supplementation. Varying exposures to radiation from combined HPS, MH, and QI lamps influenced dry weight gain and photosynthetic pigment content of hydroponically grown `Black-Seeded Simpson' lettuce (Lactuca sativa L.) seedlings. Cumulative leaf dry weight declined with increasing exposure, up to 20 hours per day, to 660 μmol·m-2·s-1 of photosynthetically active radiation (PAR) from HPS lamps concomitant with constant 20 hours per day of 400 m mol·m-2·s-1 from MH + QI lamps. Leaves progressively yellowed with increasing exposure to radiation from the three-lamp combination, corresponding to lower specific chlorophyll content but not to specific carotenoid content. Lettuce grown under 20-hour photoperiods of 400, 473, or 668 μmolm·m-2·s-1 from HPS radiation alone had the highest leaf dry weight at a PPF of 473 μmol·m-2·s-1. Chlorophyll, but not carotenoid specific content, decreased with each incremental increase in PPF from HPS lamps. Doubling the level of N in nutrient solution and supplying it as a combination of NH4+ and NO3- partially ameliorated adverse effects of high PPF on growth and pigment content relative to treatments using single-strength N as NO3–.
Tomato Transplant Morphology Affected by Handling and Storage
Authors: Leskovar Daniel I. , Cantliffe Daniel J.
Published: February 2019

Shoot and root growth changes in response to handling and storage time in `Sunny' tomato (Lycopersicon esculentum Mill.) transplants were investigated. Transplants, 45 days old, were stored either in trays (nonpulled) or packed in boxes (pulled) for 0, 2, 4, 6, or 8 days at 5 and 15C. Also, 35-day-old nonpulled and pulled transplants were kept in darkness at 20/28C for 0, 1, 2, or 3 days. At SC, pulled transplants had longer and heavier stems, a higher shoot: root ratio, higher ethylene evolution, and lower root dry weight than nonpulled transplants. At 15C, pulled transplants had more shoot growth than nonpulled transplants. Nonpulled, initially 35-day-old transplants had heavier shoots and roots and higher (7.0 t·ha-1) yields of extra-large fruit than pulled transplants (4.1 t·ha-1), but there were no differences in the total yields of marketable fruits.
Forcing Irradiance, Temperature, and Fertilization Affect Quality of `Gloria' Azalea
Authors: Black Lori A. , Nell Terril A. , Barrett James E.
Published: February 2019

Dormant-budded `Gloria' azaleas (Rhododendron sp.) were used to observe the effect of forcing irradiance, temperature, and fertilization on postproduction performance after flower bud dormancy had been broken. Four experiments were conducted during forcing, the treatments for each experiment were: Expt. 1, three forcing irradiances (200,460, and 900 μmol·m-2·s-1) and three postproduction irradiances (4, 8, and 16 μmol·m-z·s-1); Expt. 2, three forcing irradiances (320, 560, and 1110 μmol·m-2s-l); Expt. 3, three controlled day/night temperatures (18/16C, 23/21C, and 29/27C); Expt. 4, fertilizer applied for 7, 14, or 28 days at either 150 or 300 mg N/liter (12% nitrate, 8% ammoniacal) 20N-4.8P-16K soluble fertilizer at every watering, control plants did not receive fertilizer. Days to harvest (time until plants had eight individual open flowers) was less at the high forcing irradiances and temperatures and when fertilizer was applied during forcing. Flower color was less intense at the low forcing irradiance levels, high temperatures, and when duration of fertilization was prolonged and concentration was high. There were more open flower inflorescences at week 2 of postproduction at high forcing irradiance levels, but their number was not affected by forcing temperature or fertilization. Postproduction longevity was shorter when forcing was at 29/27C (day/night) and when plants were fertilized for 28 days at 300 mg N/liter, but was not affected by forcing or postproduction irradiance.
Substrate Moisture Level Governs the Germination of Verbena Seed
Authors: Carpenter William J. , Maekawa Susumu
Published: February 2019

Verbena (Verbena × hybrida Voss) seed germination varied with the water content of the substrate. Total germination percentages (G) were highest when substrates were 75% to 100% saturated and progressively declined with increased free distilled water (FDW) on the blotter paper substrate. Natural differences in G among cultivars at favorable substrate moisture levels increased when free water was present. Removing the seed hilums did not increase G of `Romance Scarlet' on a substrate with FDW, but significantly increased the G of `Showtime Blaze' and `Red A'. Au inverse relationship was found between seed moisture contents and G at high substrate moisture levels. `Romance Scarlet', `Showtime Blaze', and `Red A' had 64%, 73%, and 84% seed moisture contents and G of 72%, 18%, and l0%, respectively. The period of sensitivity to excessive water during germination was day 2 for `Red A' and days 2 and 3 for `Showtime Blaze'. The G of `Romance Scarlet' seed was not reduced when placed on a substrate containing FDW for 1 day. Removal of seed hilums from `Red A' significantly increased G during day 2 for seeds on a substrate containing FDW.
Poinsettia Developmental and Postproduction Responses to Growth Retardants and Irradiance
Authors: Bailey Douglas A. , Miller William B.
Published: February 2019

Plants of Euphorbia pulcherrima Wind. `Glory' were grown under total irradiances of 13.4, 8.5, or 4.0 mol·m-2·day-1 and sprayed with water (control), 2500 mg daminozide/liter + 1500 mg chlormequat chloride/liter (D + C), 62.5 mg paclobutrazol/liter, or 4, 8, 12, or 16 mg uniconazole/liter to ascertain plant developmental and postproduction responses to treatment combinations. Anthesis was delayed for plants grown under the lowest irradiance. Anthesis was delayed by the D + C treatment, whereas other growth retardant treatments had no effect on anthesis date. Irradiance did not affect plant height at anthesis, but all growth retardant treatments decreased height over control plants. Inflorescence and bract canopy diameters were decreased at the lowest irradiance level. Growth retardants did not affect individual inflorescence diameters, but all, except paclobutrazol and 4 and 8 mg uniconazole/liter, reduced bract canopy diameter compared with control plants. Plants grown under the lowest irradiance developed fewer inflorescences per plant and fewer cyathia per inflorescence. Cyathia abscission during a 30-day postanthesis evaluation increased as irradiance was decreased; cyathia abscission was unaffected by growth retardant treatment. Leaf abscission after 30 days postanthesis was lowest for plants grown under the lowest irradiance. At 30 days postanthesis, all growth retardant treatments increased leaf abscission over controls. Results indicate that irradiance and growth retardant treatments during production can affect poinsettia crop timing, plant quality at maturity, and subsequent postproduction performance. Chemical names used: 2-chloroethyl-N,N,N-trimethylammonium chloride (chlormequat chloride); butanedioic acid mono (2,2-dimethyl hydrazide) (daminozide); β-[(4-chlorophenyl) methyl]- α -(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol), (E)-1-(p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-l-penten-3-ol (uniconazole, XE-1019).
Susceptibility of Selected Cherry Clones and Related Species to Western X-Disease
Authors: Uyemoto Jerry K. , Kirkpatrick Bruce C. , Cummins James N.
Published: February 2019

Prunus species, advanced rootstock selections, and named cherry cultivars and rootstock were bud-inoculated with the Western X-disease mycoplasma-like organism (X-MLO) and evaluated for host responses. Most accessions inoculated were susceptible to the X-MLO. Individuals from the species P. mahaleb L., P. maackii Rupr., P. serotina J.F. Ehrh., P. serrulata Lindl., and P. subhirtella Miq. did not become infected with the X-MLO despite being grafted on infected rootstock.
Vapor Phase Hydrogen Peroxide Inhibits Postharvest Decay of Table Grapes
Authors: Forney Charles F. , Rij Roger E. , Denis-Arrue Ricardo , Smilanick Joseph L.
Published: February 2019

The potential use of vapor phase hydrogen peroxide (VPHP) to prevent decay caused by Botrytis cinerea Pers. ex Fr. in table grapes (Vitis vinifera L.) was investigated. `Thompson Seedless' and `Red Globe' grapes, inoculated with Botrytis cinerea spores, were placed in polyethylene bags and flushed for 10 minutes with VPHP generated from a 30% to 35% solution of liquid hydrogen peroxide at 40C. Immediately after treatment, bags were sealed and held at 10C. Vapor phase hydrogen peroxide significantly reduced the number of terminable Botrytis spores on grapes. The number of terminable spores on `Thompson Seedless' and `Red Globe' grapes had been reduced 81% and 62%, respectively, 24 hours following treatment. The incidence of decay on inoculated `Thompson Seedless' and `Red Globe' grapes was reduced 33% and 16%, respectively, after 8 days of storage at 10C compared with control fruit. Vapor phase hydrogen peroxide reduced the decay of noninoculated `Thompson Seedless' and `Red Globe' grapes 73% and 28%, respectively, after 12 days of storage at 10C. Treatment with VPHP did not affect grape color or soluble solids content.
Brassica napus Sources of Resistance to Black Rot in Crucifers and Inheritance of Resistance
Authors: Guo H. , Dickson M.H. , Hunter J.E.
Published: February 2019

Resistance to black rot caused by the bacterium Xanthomonas campestris pv. campestris was studied in Brassica oleracea, B. campestris, and B. napus. Two accessions of B. napus, PI 199947 and PI 199949, exhibited the highest resistance so far found in cultivated Brassica spp. In B. napus, the high level of resistance was conferred by one dominant gene. In B. campestris, two Chinese cabbage accessions showed quantitative inheritance for moderate levels of resistance. Resistance was transferred to B. campestris from B. napus, but a unilateral incongruity was observed for black rot and morphology, but not for stem color or bolting. The bridge line 15 was used to transfer resistance to B. oleracea.
Evaluation of Sweetpotato Clones for Soil Insect Damage
Authors: Schalk James M. , Dukes Philip D. , Jones Alfred , Jarret Robert L.
Published: February 2019

The reactions of eight sweetpotato [Ipomoea batatas (L.) Lam.] introductions were categorized for root damage by wireworms, Diabrotica sp., Systena sp. (WDS), sweetpotato flea beetle (SPFB), and grubs. Clones were compared with resistant (`Regal') and susceptible (`SC-1149-19') entries. The number of resistant clones for the WDS, SPFB, and grubs were three, four, and one, respectively, intermediate five, four, and one, and susceptible zero, zero, and six, respectively. This test demonstrated that significant levels of soil insect resistance exist in these sweetpotato introductions for use by plant breeders.
Growth and Development of Young Asparagus Plants in Response to N Fertilization
Authors: Pitman Barbara Cohea , Sanders D.C. , Swallow W.H.
Published: February 2019

One-year-old crowns of Asparagus officinalis L. cv. Princeville were grown for up to 2 years in pots containing a mineral soil. Nitrogen concentrations ranged from O to 340 kg N/ha. Increasing N fertilizer level resulted in a decrease in total crown fructose concentration and an increase in fern growth, both leveling off at higher N levels. Crown growth was maximized at intermediate N levels. To obtain maximum crown growth and total fructose concentration, while avoiding the excessive fern growth associated with higher N fertilizer levels, ≈57 kg N/ha should be applied to asparagus during the 2nd and 3rd years of growth.
Rhizosphere pH Influences Early Root Morphology and Development of Bell Peppers
Authors: Stoffella Peter J. , DiPaola Michele Lipucci , Pardossi Alberto , Tognoni Franco
Published: February 2019

Bell peppers (Capsicum annuum L. `Early California Wonder') were seeded in glass tubes on agar-based media adjusted to pH 4.1, 5.9, or 7.3 to evaluate germination, emergence, shoot growth, and root morphology for 16-day-old seedlings. Taproot lengths were measured daily from 1 to 10 days following radicle protrusion. Time from seeding to germination (radicle protrusion) differed by only one-half day among pH treatments. Peppers in a pH 5.9 medium emerged (fully expanded cotyledons) 1 day earlier than plants grown in media at pH 4.1 or 7.3. Plants grown in a pH 5.9 medium had higher shoot and root weights and longer stems than plants grown at pH 4.1 or 7.3. Shoot: root ratios were similar regardless of medium pH. However, taproot growth rate from 1 to 10 days after radicle protrusion was faster for plants grown in a pH 5.9 than in a pH 4.1 or 7.3 medium. On average, there was one basal and one lateral root per plant and they were minimally influenced by pH. The data suggest that acidic or alkaline media adversely affect early shoot and taproot development of bell peppers, but with minimal influence on time to germination or emergence, and on subsequent lateral and basal root initiation.
Daily Tall Fescue Leaf Appearance Rate in Relation to Environmental Factors
Authors: McCarty L.B. , Haun J.R. , Miller L.C.
Published: February 2019

Methods for detecting and mathematically regressing daily tall fescue (Festuca arundinacea Schreb.) leaf appearance on environmental variables are presented. Morphological stages of leaf development were quantified and the rate of leaf appearance was linearly regressed on environmental variables. The following model was developed to predict daily tall fescue leaf appearance and was successfully tested on unrelated data: Daily leaf appearance rate = 0.016 – (2.48 × 10-4 × solar radiation) + (0.015 × precipitation 2-day lag) + (0.117 × soil moisture 3-day lag) + (8.79 × 1 0-6 × maximum air temperature × solar radiation) - (3.61 × 10-' × maximum air temperature × age) + (0.00307 × minimum air temperature × precipitation) – (4.39 × 10-4 × precipitation × age), (R2 = 0.78). Growers of tall fescue and researchers will benefit in the identification of environmental characteristics and cultural practices that significantly influence leaf appearance rate.
Container Size and Shape Influence Growth and Landscape Performance of Marigold Seedlings
Authors: Latimer Joyce G.
Published: February 2019

Seeds of marigold (Tagetes erects L. `Janie') were sown in flats of three cell sizes (inverted pyramids, Todd 080A, 100A, or 175; volume 7, 24, or 44 cm3, respectively) or in flats of different root cell configurations [Todd 100A, Grow-Tech (GT) 200, or Growing Systems (GS) 135; shaped as inverted pyramid, cylinder, or cylinder with a bottom lip, respectively]. During 2 consecutive years, plants grown in Todd 080A trays had 60% less leaf area and shoot and root dry weights than plants grown in Todd 175 trays. Plants grown in Todd 100A trays had 30% less leaf area and shoot and root dry weights than plants grown in the larger volume tray. Stem length was less affected by container size. The rate of shoot dry weight gain during the 3 weeks after transplanting in the field was greater in plants from the smaller containers (Todd 080A and Todd 100A) in 1987. Final height (7 weeks after planting) of plants from Todd 080A or Todd 100A flats was 12% and 7% less, respectively, than those of plants grown in Todd 175 flats, while final plant quality was reduced 34% and 21%, respectively, in plants from these flats in 1987. Similar, but smaller, effects were recorded in 1988. Container type had little effect on plant growth in the greenhouse and no effect on growth in the landscape. The maximum quality rating in the landscape, awarded to plants from Todd 100A flats, was 12% greater than that of plants from GT 200 flats in 1987 and 5% and 9% greater than plants from GT 200 and GS 135 flats, respectively, in 1988. Final plant performance of marigold seedlings was reduced more by root restriction or transplant size than previously reported with vegetable species.
Strawberry Responses to K Rate on a Fine Sand Soil
Authors: Albregts E.E. , Howard C.M. , Chandler C.K.
Published: February 2019

Strawberry (Fragaria × ananassa Duch.) was grown for two seasons on a fine sand soil to study the plant and fruiting response of three cultivars to K rates of O, 56, 112, 168, and 224 kg·ha-1. `Dover' total fruit yields increased linearly with rate both seasons while the maximum March yield the first season was with 170 kg K/ha. April yields increased linearly with K rate the first season. `Tufts' and `Chandler' responses to K rates were not consistent for monthly or total fruit yield. The average fruit weight of `Dover' and `Tufts' decreased linearly with increasing K rate for March and for the season in 1984, while `Dover' gave a positive linear average fruit weight response to K rate during Apr. 1986. `Dover' leaf K decreased from December to February, and K deficiency symptoms were expressed by February in treatments receiving lower rates of K. Leaf K concentrations of `Dover' correlated well with K rate.
Response of Easter Lily to Preplant Incorporation of Uniconazole into the Planting Medium
Authors: McAvoy Richard J.
Published: February 2019

Lilium longiflorum Thunb. cv. Ace grown without plant growth regulators and plants drenched with 0.5 mg a.i. ancymidol per pot following shoot emergence were compared to plants growing in a medium containing uniconazole-impregnated amendments. Uniconazole was applied at rates of 0.18, 0.018, and 0.0018 mg a.i. per pot using either impregnated rockwool (RW) or copolymer acrylamide acrylate (CA). Two other treatment groups received a uniconazole drench at potting (0.018 or 0.0018 mg a.i. per pot). Impregnated CA resulted in undesirably short lilies (i.e., plants <1.5 times the height of the pot) when 0.18 mg uniconazole per pot was incorporated into the medium; effective height control was obtained with CA at 0.018 mg/pot; no height control was observed at 0.0018 mg/pot. Similarly, final height of lilies grown in medium containing uniconazole-impregnated RW decreased as the rate of uniconazole increased. Pre-emergence potting medium drenches with uniconazole (0.018 and 0.0018 mg a.i. per pot) did not significantly affect lily growth and flowering. Ancymidol drench was less effective at retarding stem length and plant height than medium incorporation of 0.18 mg uniconazole. Flowering was not significantly affected by any treatment. Chemical names used: a-cyclopropyl-a-(4-methoxy-phenyl)-5-pyriimidine methanol(ancymidol);B-[(4-cyclophenyl)methyl]-a-(1,1-dimethylethyl)1 H-1,2,4-triazole-1-ethanol(paclobutrazol);(E)-(p-chloro-phenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol(uniconazole).
Association of the Sweetpotato Whitefly with a Silverleaf Disorder of Squash
Authors: Schuster David J. , Kring James B. , Price James F.
Published: February 2019

The sweetpotato whitefly, Bemisia tabaci (Gennadius), was associated with symptoms of a silverleaf disorder of acorn squash (Cucurbita pepo L. cvs. Table King Bush and Table Ace) in cage studies in the greenhouse. Symptoms appeared on uninfested leaves that developed after plants were infested with the whitefly. When the infested lower leaves were removed and the young leaves protected from infestation with insecticides, new growth was asymptomatic or nearly so and symptomatic leaves remained symptomatic. Symptom expression was related more to nymphal density than to adult density since the relationship between log nymph density and symptoms was linear when adult densities were equal.
Fine Structure of Apple Leaves Treated with the Sterol-inhibiting Fungicide Bitertanol
Authors: Overton S.V. , Moore L.D. , Miller O.K.
Published: February 2019

Ultrastructural observations were made of leaves of apple (Malus domestics Borkh. cv. Red Delicious) 12, 24, and 72 hours following a single foliar application of the sterol-inhibiting fungicide bitertanol. Thylakoids of chloroplasts from treated leaves were swollen and irregular and chloroplasts had lost their integrity within 12 hours after treatment. Occasionally, mitochondria looked washed out, although no other changes in membrane or organelle structures were observed. Within 24 to 72 hours, moreover, thylakoids of chloroplasts from treated leaves returned to a state similar to that of the controls. However, the numbers of starch granules in the chloroplasts of treated leaves appeared to increase throughout the 72 hours and remained somewhat higher than levels in controls. Thus, bitertanol does not appear to have a lasting effect on apple leaves. Chemical name used: ß-([1,1′-biplenyl]-4-yloxy)-α-(1,1-dimethylethyl)-1H-1,2,4-trizole-1-ethanol (bitertanol).
Interrelations of Ammonium Toxicity and Ethylene Action in Tomato
Authors: Barker Allen V. , Corey Kenneth A.
Published: February 2019

Inhibitors of ethylene synthesis and action were used to alleviate ammonium toxicity in tomato (Lycopersicon esculentum Mill. `Heinz 1350') grown on ammonium-based nutrient solutions. Aminooxyacetic acid and Ag+ were effective in reducing ammonium toxicity, whereas Co+2 and salicylic acid were not. A hypothesis was developed to integrate ammonium accumulation and ethylene biosynthesis into a mechanism for expression of plant injury from environmental stresses.
Light-emitting Diodes as a Radiation Source for Plants
Authors: Bula R.J. , Morrow R.C. , Tibbitts T.W. , Barta D.J. , Ignatius R.W. , Martin T.S.
Published: February 2019

Development of a more effective radiation source for use in plant-growing facilities would be of significant benefit for both research and commercial crop production applications. An array of light-emitting diodes (LEDs) that produce red radiation, supplemented with a photosynthetic photon flux (PPF) of 30 μmol·s-1·m-2 in the 400- to 500-nm spectral range from blue fluorescent lamps, was used effectively as a radiation source for growing plants. Growth of lettuce (Lactuca sativa L. `Grand Rapids') plants maintained under the LED irradiation system at a total PPF of 325 μmol·s-1·m-2 for 21 days was equivalent to that reported in the literature for plants grown for the same time under cool-white fluorescent and incandescent radiation sources. Characteristics of the plants, such as leaf shape, color, and texture, were not different from those found with plants grown under cool-white fluorescent lamps. Estimations of the electrical energy conversion efficiency of a LED system for plant irradiation suggest that it may be as much as twice that published for fluorescent systems.
Natural Variability in Yield of Lowbush Blueberries
Authors: Hepler Paul R. , Yarborough David E.
Published: February 2019

One hundred lowbush blueberry (Vaccinium angustifolium Ait.) clones were randomly sampled from a commercial field to estimate potential productivity. Yield data exhibited a normal distribution ranging from 300 to 17,000 kg·ha-1 with a mean of 7726 kg·ha-1. Commercial use of selected clones or improved cultivars through new plantings, interplanting into existing clones, or replacement of low-yielding clones in native stands and increasing the intensity of field management would increase the yielding potential of native lowbush blueberry fields.
Biostimulator Enhancement of Kentucky Bluegrass Sod
Authors: Goatley J.M. , Schmidt R.E.
Published: February 2019

This study was conducted to determine if foliar-applied biostimulators could enhance harvestability and transplanting of Kentucky bluegrass (Poa pratensis L.) sod. The systemic triazole fungicides propiconazole at 42 mg·m-2 and triadimefon at 150 mg·m-2 enhanced post-transplant rooting and sod strength of bluegrass. Propiconazole had the best sod enhancement effect, increasing sod tensile strength 23% and increasing transplant root lift strength 64% across three experiments. The synthetic cytokinin benzyladenine (BA) at 6 mg·m-2 and seaweed extract (SWE, a freeze-dried extract of the seaweed Ascophyllum nodosum) at 0.3 ml product/m 2 had little effect. The response to triadimefon was intermediate. Foliar applications of chelated Fe phosphate citrate at 112 mg·m-2 did not enhance sod strength or rooting of Kentucky bluegrass when applied either alone or in combination with the biostimulator materials. Chemical names used: l-(2-(2,4 -dichlorophenyl)-4-propyl-l,3-dioxo1an-2-ylmethyl)-lH-l,2,4-triazole(propiconazole);1-(4-chlorophenoxy)-3,3-dimethyl-lH-(l,2,4-triazo1-l-yl)-butanone (triadimefon);6-benzylaminopurine (BA, benzyladenine).
Germination and Morphology of Sophora secundiflora Seeds Following Scarification
Authors: Ruter John M. , Ingram Dewayne L.
Published: February 2019

Seeds of Sophora secundiflora (Ort.) Lag ex. DC. (mescal bean) were scarified with hot water or concentrated sulfuric acid to determine an optimal pretreatment for successful germination. Scanning electron micrographs indicated that the acid scarification treatment removed the seed cuticle. One-year-old seeds were successfully stored and germinated ≈2 days sooner than from the current year if both were given an acid pretreatment. Germination rate increased as acid pretreatment time increased from 30 to 120 minutes. Soaking seeds in water at room temperature or in hot water (initially 93C) for 24 hours had no effect on germination.
Evapotranspiration Rates of Eleven Zoysia Genotypes
Authors: Green R.L. , Sifers S.I. , Atkins C.E. , Beard J.B.
Published: February 2019

We compared evapotranspiration (ET) rates for 11 Zoysia genotypes, encompassing two species and their hybrid, maintained at nonlimiting soil moisture under field conditions and in an environmental chamber of high evaporative potential. ET rate relationships to leaf area [leaf extension rate (LER)], canopy resistance [shoot density (SHD)], and internal resistance [abaxial (AB) and adaxial (AD) leaf blade stomatal densities] characteristics were determined. Three-year ET rate means were not significantly different among genotypes in the field study, but ET rates among genotypes differed significantly under the higher evaporative potential of an environmental-chamber study. ET rate was not significantly correlated with LER for either the data from the field or the chamber. ET rates of both types of tests also were not significantly correlated with SHD or AB or AD leaf blade stomatal density. Data from field and environmental-chamber research suggest that differences of individual morphological traits among the 11 zoysiagrasses do not influence the ET rate when measured from minilysimeters maintained at nonlimiting soil moisture.
Zinc Deficiency Inhibits Chlorophyll Synthesis and Gas Exchange in `Stuart' Pecan
Authors: Hu Hening , Sparks Darrell
Published: February 2019

Leaves of `Stuart' pecan [Carya illinoensis (Wangenh.) C. Koch] with various levels of Zn deficiency were analyzed for physiological indicators of leaf vigor. Leaf chlorophyll content, stomatal conductance, and net photosynthesis were adversely affected by Zn deficiency. In leaves with severe Zn deficiency, each of these indicators increased 3- to 5-fold with a doubling of leaf Zn concentration, but stabilized as leaf Zn approached the sufficiency range (14 μg·g-1). High intercellular CO2 associated with low net photosynthesis indicates that stomatal aperture was not the cause of the reduction of net photosynthesis under Zn deficiency.
Quality of Carambolas Subjected to Postharvest Hot Water Immersion and Vapor Heat Treatments
Authors: Hallman Guy J.
Published: February 2019

`Arkin' carambolas (Averrhoa carambola L.) were subjected to the fruit fly quarantine treatments of hot water immersion at 43.3 to 43.6C for 55 or 70 rein, 46.0 to 46.3C for 35 or 45 rein, or 49.0 to 49.3C for 25 or 35 rein, or vapor heat at 43.3 to 43.6C for 90 to 120 rein, 46.0 to 46.3C for 60 or 90 rein, or 49.0 to 49.3C for 45 or 60 min. Marketability, color, weight loss, internal appearance, flavor, total acids, and soluble solids content were determined. The 49.0 to 49.3C treatments resulted in excessive damage to the carambolas 2 to 4 days after treatment. There were no statistically significant differences in the variables measured among the other treatments and control; however, heat-treated carambolas appeared duller in color than control fruits. Overall, fruit treated at 46.0 to 46.3C lost significantly more weight than that treated at 43.3 to 43.6C.
Cold Hardiness of Six Cultivars of Chinese Elm
Authors: Lindstrom Orville M. , Dirr Michael A.
Published: February 2019

Cold hardiness levels of six cultivars of Chinese elm (Ulmus parvifolia Jacq.), `Select 380', `Orange Ribbon 740', `Emerald Isle', `Emerald Vase', `Drake', and `King's Choice', were determined over eight sample dates from 31 Aug. 1988 to 16 May 1989 and for `Emerald Vase' and `Drake', over three dates from 14 Feb. 1988 to 25 Apr. 1988. All cultivars tested achieved a maximum cold hardiness in December and January of – 21 to – 24C, except `King's Choice', which survived exposure to at least – 30C. `Emerald Isle' and `Emerald Vase' acclimated earlier (both – 9C on 31 Aug.) and reacclimated later (– 6 and – 9C, respectively, on 16 May) than other cultivars tested. `Emerald Vase' and `Drake' exhibited similar cold hardiness levels over the two years tested.
Fruit Morphology and Fruit Strength in a Seedling Population of Red Raspberry
Authors: Robbins JoAnn , Moore Patrick P.
Published: February 2019

Weight and morphological characteristics of red raspberry (Rubus idaeus L.) fruit, including drupelets (height, diameter, number), receptacle cavities (depth, diameter), and pits (individual weight), were measured on 78 seedlings from the cross `Chief' × `Chilliwack'. Fruit strength, as measured by compression, correlated with fruit weight, drupelet number, receptacle cavity depth, and individual pit weight. Fruit weight was positively correlated with all morphological characteristics. Individual pit weight, drupelet height, and drupelet number provided the largest component contributions to fruit strength as measured by path analysis.
Improving Seedling Vigor in Sexual Seeds of Potato Under High Temperature
Authors: Pallais Noël E. , Espinola Nelly Y. , Falcon Rosario M. , Garcia Ruperto S.
Published: February 2019

Sexual seeds of potato (Solanum tuberosum L.) usually emerge poorly under high-temperature conditions (> 25 C). A seedling vigor study was conducted during the warm season (1988-89) in Lima, Peru, and the results of two representative tests. are reported. Two presowing treatments and a rinsed control were compared for seedlingstand establishment in a screenhouse with old (>18 months) and new (> 6 months) sexual seeds of three potato crosses. The treatments consisted of soaking the seed in solutions of KN03 + K3P04 at – 1.0 MPa (priming) and gibberellic acid at 1500 ppm (GA1500). Seedling vigor was lower at 34C (February test) than at 29C (November test). In both tests, overall seedling performance was highest in seed of the cross Atlantic × LT-7. Old seed was more vigorous than new seed, particularly when the crosses Atzimba × R128.6 (B2) and Serrana × LT-7 (Cl) were tested at 34C. Priming increased percentage of early (10 days) emergence over the other treatments at 34C and increased seedling dry weight in both tests. GA1500 increased percentage of final (17 days) emergence in crosses B2 and Cl, as compared to rinsing, except at 29C, where there were no significant differences in old seed. For sowing true potato seed at high temperature, a) the genotype is a crucial factor, b) sufficient seed storage (> 18 months) may be essential, and c) seed priming is more effective than the standard GA1500 treatment.
Identification of Sweetpotato Cultivars Using Isozyme Analysis
Authors: Kennedy Larry S. , Thompson Paul G.
Published: February 2019

The enzymes alcohol dehydrogenase, diaphorase, esterase, glutamate dehydrogenase, glucosephosphate isomerase, isocitrate dehydrogenase, malate dehydrogenase, malic enzyme, 6-phosphogluconate dehydrogenase, phosphoglucomutase, shikimate dehydrogenase, and xanthine dehydrogenase were analyzed by starch gel electrophoresis of leaf tissue from nine sweetpotato [Ipomoea batatas (L.) Lam.] cultivars. Bands of most enzymes were well-defined. Polymorphisms were found in nine enzymes, and cultivars were identified by comparing polymorphisms.
Family Differences in Growth and Flowering in Young Southern Magnolia
Authors: Greene Thomas A.
Published: February 2019

Height and caliper (age 3 years), and flower count (age 3.5 years) were evaluated for 36 open-pollinated families of Magnolia grandiflora L. outplanted in two genetic tests in Bexar County, Texas. Significant family differences existed for height, caliper, number of flowers per tree, and percent of trees flowering in both tests. Family heritability estimates for all traits ranged from 0.72 to 0.92. Coefficients of genetic prediction (CGP) between growth and flowering characteristics were small but positive; CGP between height and percent of trees flowering was 0.28 and 0.24 in the two tests. Early growth rate and flowering appeared to be under strong genetic control; thus, improvement through selection would be efficient. However, both traits should be evaluated since the genetic relationship between them was weak.
Growth and Boron Uptake of Five Pecan Cultivar Seedlings
Authors: Picchioni G.A. , Miyamoto S. , Storey J.B.
Published: February 2019

Growth and B uptake of five pecan [Carya illinoensis (Wangenh.) C. Koch] seedling cultivars were evaluated in two greenhouse experiments. Seedlings were exposed for 7 to 8 months to various B-containing irrigation solutions. In one study, the growth of `Apache', `Riverside', and `Burkett' seedlings declined significantly with a 5.0-mg B/liter application that provided 12.3 mg B/liter in the soil saturation extract. In the second study, B application of 2.5 mg·1iter-1 (6.4 mg·liter-1 in the saturation extract) reduced growth of `Western' and Wichita' seedlings. Seedling sources differed in susceptibility to B applications. `Apache' and `Wichita' seedlings were the more sensitive cultivars in the experiments. Leaf B concentrations increased linearly with concentrations in the saturation extract (r = 0.96 to 0.99), but did not depend on the cultivar. Boron toxicity (leaf interveinal chlorosis and tip necrosis) occurred within several weeks following B application of 1.25 to 2.5 mg·liter-1 (2.8 to 6.6 mg·liter-1 in the saturation extract, depending on cultivar). Three months later, chlorotic areas became necrotic in leaves containing >900 mg B/kg dry weight. Severe necrosis and some defoliation occurred when B concentrations were increased further. Leaves with no injury contained ≤325 mg B/kg.