bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of Prodiamine as a Preemergence Herbicide to Control Annual Bluegrass in Kentucky Bluegrass
Authors: Dernoeden Peter H.
Published: February 2019

Annual bluegrass (Poa annua L.) is an intractable weed problem on golf courses. Much has been written about annual bluegrass, but there is little documentation of regional germination period(s) and the proper timing of preemergence herbicides targeted for the control of the annual biotype (P. annua ssp. annua [L.] Timm.=AB). The objectives of this field study were to determine the optimum prodiamine rate and timing for effective AB control. The turf was a mature stand of `Kenblue' Kentucky bluegrass (Poa pratensis L.) maintained under conditions similar to those imposed for golf course roughs. Three rates of prodiamine (0.36,0.73, and 1.1 kg·ha-1) were applied on three dates in 1995 (11 Aug., 14 Sept., and 13 Oct.) and 1996 (29 Aug., 16 and 30 Sept.). All rates applied 11 Aug. or 14 Sept. 1995, and 29 Aug. or 16 Sept. 1996 effectively controlled AB. None of the rates applied 13 Oct. 1995 reduced AB cover, and the 0.36 kg·ha-1 rate applied 30 Sept. 1996 provided relatively poor AB control. Data and observations indicated that the major germination period for AB was between late September and early December. Effective AB control was achieved whenever prodiamine, regardless of rate, was applied between mid-August and mid-September. These prodiamine rates and this application window may be effective only in relatively high cut turf (i.e., >5.0 cm) in the mid-Atlantic region. Chemical names used: O,O-bis(1-methylethyl) S-{2-[(phenylsulfonyl)amino]ethyl} phosphorodithioate (bensulide); N3,N3-di-n-propyl-2,4-dinitro-6-(trifluoromethyl)-m-phenylenediamine (prodiamine).
Influence of Media Components on Efficacy of Paclobutrazol in Inhibiting Growth of Broccoli and Petunia
Authors: Million J.B. , Barrett J.E. , Nell T.A. , Clark D.G.
Published: February 2019

Three experiments were conducted to evaluate media component effects on paclobutrazol activity. In Expts. 1 and 2, a broccoli (Brassica oleracea var. botrytis L.) seedling bioassay was used to compare the activity of paclobutrazol at six concentrations (0-0.32 mg·L-1). Results from Expt. 1 indicated that an average of 4-, 5-, and 10-fold higher concentrations were required in old composted pine bark, fresh pine bark, and composted pine bark samples, respectively, to achieve the same activity observed in sphagnum peatmoss (peat) samples. Activity in coir was similar to that in peat while activity in vermiculite and perlite was greater than that in peat. Activity in a fibrous peat sample was greater than in two less-fibrous peat samples. Results from Expt. 2 indicated that paclobutrazol activity was reduced more in the fine (<2 mm) fraction of fresh and composted bark samples than in medium (2-4 mm) or coarse (>4 mm) fractions. In Expt. 3, petunia {Petunia hybrida Vilm. `Madness Red') was grown in a mixture of either 60% composted pine bark: 0% peat or 0% composted bark: 60% peat. The paclobutrazol concentration required to achieve the same size control was 14 times higher in the former mixture than in the latter. Thus, media components differ greatly in their influence on paclobutrazol activity and the bioassay procedure may serve as a useful tool for predicting media-paclobutrazol interactions. Chemical name used: (±)-(R*,R*)-β-[(4-chlorophenyl)methyl]-α-(l,l-dimethyl)-lH-l,2,4-triazole-l-ethanol (paclobutrazol).
Stagonospora convolvuli LA39 for Biocontrol of Field Bindweed Infesting Cotoneaster in a Cemetery
Authors: Guntli Daniel , Pfirter Hanspeter A. , Moënne-Loccoz Yvan , Défago Geneviève
Published: February 2019

Field bindweed (Convolvulus arvensis L.) infests roadsides, hedges, and parks, and is difficult to control with herbicides. In this work, the potential of the mycoherbicide Stagonospora convolvuli Dearness & House strain LA39 for use as a biological control of field bindweed was tested in a cemetery, where a groundcover of cotoneaster was extensively infested by the weed. Application of S. convolvuli resulted in extensive necrosis of field bindweed leaves within 20 days, and necrosis became more extensive in the 20 following days. Bindweed density decreased continuously to about half of that in the uninoculated control plots within 40 days after application. No effect on emergence of field bindweed was observed in the year following the application of S. convolvuli. In conclusion, S. convolvuli may be useful as a mycoherbicide for the control of field bindweed in amenity areas but it would need to be applied every year.
Storage Quality of Apples following Natural and Artificial Tufted Apple Bud Moth Feeding Injury
Authors: Barden Cynthia L. , Hull Larry A.
Published: February 2019

`Golden Delicious', `Delicious', and `York Imperial' apples (Malus ×domestica Borkh.) with various amounts of tufted apple bud moth (TABM) [Platynota idaeusalis (Walker)] feeding injury were evaluated for quality at harvest and following storage in air and controlled atmosphere. In addition, apples were artificially injured during two seasons to mimic TABM feeding injury. There was little or no effect of natural TABM injury on the quality of apples in many experiments. At harvest, firmness was not influenced by natural TABM injury, soluble solids concentration (SSC) was increased in three of 11 experiments, and starch levels decreased in two of 11 experiments. These results indicate a slight advancement of maturity of injured fruit. More severely injured fruit tended to have more decay after storage than fruit with less injury. Some injury, especially first brood injury, up to ≈7 to 10 mm2 surface damage, can be tolerated without compromising storage quality of processing apples. However, severe injury (>79 mm2) can increase decay. Second brood injury, whether caused by natural feeding of TABM or through artificial means, usually caused a higher incidence of decay than first brood injury. Artificial injury imposed close to harvest led to more decay in storage than did similar injury imposed earlier.
Quality and Disease Incidence of `Waimanalo Solo' Papaya following Forced-air Heat Treatments
Authors: Lay-Yee Michael , Clare Graeme K. , Petry Robert J. , Fullerton Robert A. , Gunson Anne
Published: February 2019

Papaya fruit (Carica papaya L. cv. Waimanalo Solo), at color break ripeness, were either not heated (controls) or forced-air heated to center temperatures of 47.5, 48.5, or 49.5 °C, and held at these temperatures for 20, 60, 120, or 180 minutes. Following heat treatment, fruit were hydrocooled until reaching a center temperature of 30 °C, treated or not treated with prochloraz, allowed to ripen at 26 °C and then assessed for quality. Treatment at 48.5 °C or 49.5 °C for ≥60 minutes was associated with skin scalding. No significant scald was observed in other treatments or in the controls. Both control and heat-treated fruit had relatively high levels of decay. Heat treatment increased the incidence of body rots but did not affect the incidence of stem-end rots. Prochloraz treatment significantly reduced the incidence of decay. With the inclusion of a prochloraz treatment to control postharvest decay, fruit tolerated treatments of 47.5 °C for up to 120 minutes, and 48.5 °C and 49.5 °C for 20 minutes with no significant damage. Chemical name used: 1-N-propyl-N-(2-(2,4,6-(trichlorophenoxy)ethyl)-1H-imidazole-1-carboxamide (prochloraz).
Flowering of Leucanthemum ×superbum `Snowcap' in Response to Photoperiod and Cold Treatment
Authors: Runkle Erik S. , Heins Royal D. , Cameron Arthur C. , Carlson William H.
Published: February 2019

`Snowcap' Shasta daisy [Leucanthemum ×superbum Bergmans ex. J. Ingram (syn: Chrysanthemum ×superbum, C. maximum)] was grown under various photoperiods and temperatures to determine their effects on flowering. In the first experiment, plants were held for 0 or 15 weeks at 5 °C and then were grown at 20 °C under the following photoperiods: 10, 12, 13, 14, 16, or 24 hours of continuous light or 9 hours with a 4-hour night interruption (NI) in the middle of the dark period. Without cold treatment, no plants flowered under photoperiods ≤14 hours and 65% to 95% flowered under longer photoperiods or NI. After 15 weeks at 5 °C, all plants flowered under all photoperiods and developed three to four or 10 to 11 inflorescences under photoperiods ≤14 or ≥16 hours, respectively. To determine the duration of cold treatment required for flowering under short photoperiods, a second experiment was conducted in which plants were treated for 0, 3, 6, 9, 12, or 15 weeks at 5 °C, and then grown at 20 °C under 9-hour days without or with a 4-hour NI. Under 9-hour photoperiods, 0%, 80%, or 100% of plants flowered after 0, 3, or ≥6 weeks at 5 °C, and time to flower decreased from 103 to 57 days as the time at 5 °C increased from 3 to 12 weeks. Plants that were under NI and received ≥3 weeks of cold flowered in 45 to 55 days. For complete and rapid flowering with a high flower count, we recommend cold-treating `Snowcap' for at least 6 weeks, then providing photoperiods ≥16 hours or a 4-hour NI during forcing.
Spectral Filters Affect Growth, Flowering, and Postharvest Quality of Easter Lilies
Authors: Kambalapally V.R. , Rajapakse Nihal C.
Published: February 2019

The role of light quality on growth, flowering, and postharvest characteristics of `Nellie White' Easter lilies (Lilium longiflorum Thunb.) was evaluated in two growing seasons using 4% CuSO4 and water (control) as spectral filters. The CuSO4 filter significantly reduced plant height and internode length. However, the height reduction was smaller in the 1994—95 season (9%) than in the 1995—96 growing season (32%). The number of days to flower bud appearance and flower opening, and the number and diameter of flowers were not significantly affected by the spectral filters in either season. The CuSO4 filters reduced flower longevity by 3 days in nonstored plants, and by 5 days when plants were subjected to 1 week storage at 4 °C prior to placing in the postharvest room. Results suggest that spectral filters are effective in controlling height and producing compact Easter lily plants without causing a delay in flowering or reducing number of flowers per plant but flower longevity can be adversely affected.
Performance of Transgenic Tomatoes Expressing Cucumber Mosaic Virus CP Gene under Epidemic Conditions
Authors: Murphy John F. , Sikora Edward J. , Sammons Bernard , Kaniewski Wojciech K.
Published: February 2019

Three processing tomato (Lycopersicon esculentum Mill.) lines engineered to express the cucumber mosaic virus (CMV) capsid protein (CP) gene were evaluated in the summers of 1995 and 1996 under high levels of naturally occurring CMV disease pressure. One tomato line expressed the capsid protein gene from a subgroup II isolate of CMV (line 11527), whereas two lines (12261 and 12295) expressed the capsid protein genes from a CMV subgroup I and a subgroup II isolate. Evaluation of CMV incidence based on symptomatic plants revealed that only 9% and 8% of the plants in line 11527 were infected in 1995 and 1996, respectively, 5 weeks after being transplanted. None of the plants in line 12261 developed symptoms in 1995, whereas 26% were symptomatic in 1996. There were no symptomatic plants in line 12295 in either the 1995 or the 1996 trial. In contrast to the CMV transgenic lines, 96% and 95% of the susceptible control plants were symptomatic by the 5-week rating period. CMV incidence in the CMV transgenic lines was much higher when infection was based on detection of virus by enzyme-linked immunosorbent assay (ELISA). This was particularly true in the 1996 trial where no less than 97% of the plants within a treatment were determined to be infected. Though a relatively high percentage of the transgenic plants were infected, the amount of CMV that accumulated in these plants was significantly less than in the susceptible controls, which may explain the occurrence of the attenuated symptoms. Despite CMV infection of the transgenic lines in the Alabama field trials, the performance of these lines could be of practical value to growers.
Genetics of Anthocyanin Deficiency in Sarracenia L.
Authors: Sheridan Philip M. , Mills Richard R.
Published: February 2019

Sarracenia L. is a genus of insectivorous plants confined to wetlands of the United States and Canada. Green mutants, lacking red pigmentation in the leaves, flowers, and growing point, have been found in most Sarracenia species. Controlled crosses were made using green mutants from S. rubra Walter ssp. gulfensis Schnell, S. purpurea L., S. psittacina Mich., and S. leucophylla Raf. Self-pollination of mutant green individuals in four different species resulted in green offspring, whereas reciprocal crosses with respective wild-types resulted in red offspring. Three of six self-pollinated heterozygous S. rubra ssp. gulfensis yielded offspring exhibiting a 3 red : 1 green ratio. Progeny from a testcross and two self-pollinated heterozygous plants of S. purpurea fit the expected ratios, whereas offspring from two S. purpurea crosses had significant deviations in field and laboratory sowing experiments. Offspring from testcrosses with S. rubra Walter ssp. jonesii (Wherry) Wherry met expected ratios under field conditions. Interspecific crosses between green individuals resulted in green offspring. These results suggest that anthocyanin pigmentation is controlled by two alleles at a single locus, with red dominant to green.
Potato Transformation to Combine Natural and Engineered Resistance for Controlling Tuber Moth
Authors: Douches D.S. , Westedt A.L. , Zarka K. , Schroeter B. , Grafius E.J.
Published: February 2019

Potato tuber moth (Phthorimaea operculella Zeller) is a highly destructive pest of the cultivated potato (Solanum tuberosum L.) in the tropics and subtropics and causes significant damage to both leaves and tubers. Development of host plant resistance is a central component of an integrated pest management (IPM) program for potato tuber moth. The purpose of this research was to augment natural resistance by transforming potato with a codon-modified CryV-Bt gene using Agrobacterium-mediated techniques. `Lemhi Russet' potato and two clones with different host plant resistance mechanisms, USDA8380-1 (leaf leptines) and L235-4 (glandular trichomes), were transformed with the CryV-Bt gene. Gene integration of regenerated plants was confirmed by polymerase chain reactions and Southern analyses; gene transcription was evaluated by northern analyses. Detached leaf bioassays showed that high levels of Bt expression occurred in the CryV-Bt transgenic lines (`Lemhi Russet' and L235-4), providing up to 96% control of potato tuber moth larvae, compared with 3% and 54% control in L235-4 and USDA8380-1, respectively. These transgenic lines can be used for breeding purposes to develop cultivars for (and eventual introduction into) IPM systems.
Seed Lines, Population Density, and Root Size at Harvest Affect Quality and Yield of Cut-and-peel Baby Carrots
Authors: Lazcano Carlos A. , Dainello Frank J. , Pike Leonard M. , Miller Marvin E. , Brandenberger Lynn , Baker Larry R.
Published: February 2019

Carrot (Daucus carota Mill. cv. Caropak) was studied under four population densities, and three numbers of seed lines per bed, and was harvested under three root size harvest parameters. Four phases (cutting, grading, peeling, and marketable yield) in the cut-and-peel baby carrot process were evaluated. Root length was most desirable when plots were harvested when 25% to 35% of the roots measured > 2 cm in diameter. Roots were longest (14.7 cm) in the treatments containing six seed lines per bed. The harvest criteria of 25% to 35% root diameter >2 cm also produced the highest fresh mass (48.1 t·ha-1), and the highest cut and graded mass (37.7 and 32.3 t·ha-1, respectively). A population density of 321 plants/m2 produced the highest fresh and cut mass. Percent cut waste (21.6% crowns and tips) was not affected by root size at harvest, but percent graded waste was lowest (14.2%) when plants were harvested at the greatest root size. Four seed lines per bed produced the highest graded (18.4%), and total waste (61.2%), but not cut waste. The lowest total waste, estimated at 59.7% and the highest projeced marketable yield (19.4 t·ha-1) occurred when roots were harvested using the 25% to 35% root diameter >2-cm parameter. Total waste and marketable yield were obtained using a fixed waste value of 40% in the peeling phase (peeling, polishing, and grading before packing). This percentage could vary depending on the equipment specifications and quality control of a given processing facility. Root size at harvest proved to be the main factor affecting projected marketable yield of cut-and-peel baby carrots at the population densities used in this study.
13C-nmr Spectroscopy to Monitor Sugars in Pitch of Internodes of a sh2 Corn at Developmental Stages
Authors: Russo V.M. , Williamson J. , Roberts K. , Wright J.R. , Maness N.
Published: February 2019

Sugars move through stalks to be deposited in kernels in sweet corn (Zea mays L.). Concentrations of sugars in stalks change as plants pass through developmental stages. To follow such changes, carbon-13 nuclear magnetic resonance spectroscopy (C-nmr), a technology that can measure concentrations of sugars in tissues, was compared with analysis by high-performance liquid chromatography (HPLC). A shrunken-2 hybrid (cv. Illini Gold), was monitored from mid-whorl to fresh-market maturity (R3). Internodes near the base of the stalk, just below the ear, and between an ear and the tassel were sampled at each developmental stage. Chemical shifts in C-nmr spectra were measured in parts per million hertz (ppm) down-field relative to tetramethyl silane. Through silk emergence (R1) C-nmr spectra were similar regardless of internode, having line positions between 60 and 105 ppm. Unique lines for glucose, fructose, and sucrose were at 96, 98, and 104 ppm, respectively, and mole fractions were similar to those determined by HPLC. The highest concentrations were recorded at R1 for sucrose (26.1 mg·mL-1), from tasseling (VT) through R3 for fructose (avg. 30.4 mg·mL-1), and from VT to R1 for glucose (avg. 32 mg·mL-1). Carbon-13 nuclear magnetic resonance spectroscopy can be used, with minimal sample handling, to monitor sugar concentrations in sweet corn.
Photosynthetic Photon Flux, Photoperiod, and CO2 Concentration Affect Growth and Morphology of Lettuce Plug Transplants
Authors: Kitaya Yoshiaki , Niu Genhua , Kozai Toyoki , Ohashi Maki
Published: February 2019

Lettuce (Lactuca sativa L. cv. Summer-green) plug transplants were grown for 3 weeks under 16 combinations of four levels (100, 150, 200, and 300 μmol·m-2·s-1) of photosynthetic photon flux (PPF), two photoperiods (16 and 24 h), and two levels of CO2 (400 and 800 μmol·mol-1) in growth chambers maintained at an air temperature of 20 ±2 °C. As PPF increased, dry mass (DM), percent DM, and leaf number increased, while ratio of shoot to root dry mass (S/R), ratio of leaf length to leaf width (LL/LW), specific leaf area, and hypocotyl length decreased. At the same PPF, DM was increased by 25% to 100% and 10% to 100% with extended photoperiod and elevated CO2 concentration, respectively. Dry mass, percent DM, and leaf number increased linearly with daily light integral (DLI, the product of PPF and photoperiod), while S/R, specific leaf area, LL/LW and hypocotyl length decreased as DLI increased under each CO2 concentration. Hypocotyl length was influenced by PPF and photoperiod, but not by CO2 concentration. Leaf morphology, which can be reflected by LL/LW, was substantially influenced by PPF at 100 to 200 μmol·m-2·s-1, but not at 200 to 300 μmol·m-2·s-1. At the same DLI, the longer photoperiod promoted growth under the low CO2 concentration, but not under the high CO2 concentration. Longer photoperiod and/or higher CO2 concentration compensated for a low PPF.
Sodium Chloride Concentration Affects Early Growth and Nutrient Accumulation in Taro
Authors: Hill Steven , Abaidoo Robert , Miyasaka Susan
Published: February 2019

The growth and nutrient accumulation responses of taro [Colocasia esculenta (L.) Schott, cv. Bun long] to varying sodium chloride concentrations were studied in an aerated hydroponic system. Vegetative propagules were grown at seven levels of NaCl (0, 5, 10, 20, 40, 60, and 80 mm) for 43 days. We estimated the NaCl tolerance threshold (95% of maximum growth) to be at 4.9 mm solution NaCl. Relative dry-matter yield decreased 1.6% per mm increase in solution NaCl above 4.9. These values for tolerance threshold and response slope led us to classify this taro cultivar as sensitive to salinity. As solution NaCl levels increased, Na concentration in petiole and root tissues increased, but not in lamina (leaf blade) tissues. This implies the existence of an effective mechanism for excluding excess Na, in spite of a lack of tolerance to solution NaCl in terms of growth response. Chloride concentration increased in all plant tissues with increasing solution NaCl levels; the greatest increase occurred in petiole tissue, and the lowest in lamina tissue, indicating some ability to partition Cl levels within the plant. Tissue concentrations of Ca and Mg, but not of K, were reduced by high solution NaCl levels.
Protein Productivity and Economic Feasibility of Dual-purpose Cowpea
Authors: Ahenkora K. , Adu-Dapaah H.K. , Asafo-Adjei B. , Asafu-Agyei J.N. , Adjei J. , Konadu E.Y. Oppong
Published: February 2019

The effect of leaf harvest on the total protein yield and economic viability of cowpea [Vigna unguiculata (L.) Walp.] was evaluated under tropical field conditions. Productivity was measured as edible dry weight and protein yield in kg·ha-1 dry-weight basis (dwb). Calculation of the economic feasibility of the dual-purpose cowpea (leaf and seed harvest) vs. seed-only harvest was based on the net income. Each cultivar was grown on four row plots, with rows 60 cm apart × 5 m long. Only the two central rows were harvested. Two treatments (leaf harvest and no leaf harvest) constituted the main plots, with the varieties as subplots. Leaf harvest was restricted to the most recent, fully expanded third and fourth trifoliate leaves from the apical bud, and extended from 28 days after planting until 50% flowering. Significant (P < 0.05) cultivar differences were observed for leaf yield, seed yield, maturity, and protein yield. Dual-purpose use extended mean time to maturity by 6 days. The mean seed yield across 12 cultivars was 1260 and 976 kg·ha-1 for seed-only vs. dual-purpose, respectively. Leaf harvest reduced mean seed protein yield for six cultivars by 23%. The mean gross incomes from the dual-purpose and seed-only harvests were $1092 and $912, respectively, but the protein productivity and net income for the dual-purpose system were 1.4 and 1.5 times as great, respectively, as for the seed-only harvest system. Thus, the increased protein yield associated with the dual-purpose harvest was financially warranted.
Sprouting Temperature and Growth Regulators Influence Cut Flower Quality of Sandersonia aurantiaca
Authors: Davies Lindsay J. , Brooking Ian R. , Catley Jocelyn L. , Halligan Elizabeth A.
Published: February 2019

Tubers of Sandersonia aurantiaca Hook. were soaked in 1000 mg·L-1 GA3, 20 mg·L-1 uniconazole, 200 mg·L-1 benzyladenine, or water for 2 hours and then sprouted at 12, 18, or 24 °C. The effects of these treatments on flower stem quality were then determined at forcing temperatures of 18, 24, or 30 °C. Stem length increased with sprouting temperature only at a forcing temperature of 18 °C. Floret numbers increased with sprouting temperature at all forcing temperatures, but the effect was greatest at the 18 °C forcing temperature. The 12 °C sprouting treatment reduced floret numbers at all forcing temperatures. Soaking tubers in GA3 increased stem length but drastically reduced floret numbers, while soaking in uniconazole reduced stem length but had no significant effect on floret numbers. Soaking in BA strongly promoted branching, which resulted in large increases (>30%) in floret numbers per stem with little change in stem length. Of the three growth regulators, only BA was effective in improving cut flower stem quality. Chemical names used: gibberellic acid (GA3); (E)-(+)-(S)-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ene-3 -ol (uniconazole); N6-benzylamino purine (benzyladenine; BA).
Irradiance, Temperature, and Carbon Dioxide Enrichment Affect Photosynthesis in Phalaenopsis Hybrids
Authors: Lootens P. , Heursel J.
Published: February 2019

The short-term effects of photosynthetic photon flux (PPF), day/night temperatures and CO2 concentration on CO2 exchange were determined for two Phalaenopsis hybrids. At 20 °C, the saturating PPF for photosynthesis was 180 μmol·m-2s-1. At this PPF and ambient CO2 level (380 μL·L-1), a day/night temperature of 20/15 °C resulted in the largest daily CO2 uptake. Higher night temperatures probably increased the respiration rate and lowered daily CO2 uptake in comparison with 20/15 °C. An increase in the CO2 concentration from 380 to 950 μL·L-1 increased daily CO2 uptake by 82%.
Short-term Heat Conditioning of Grapefruit to Alleviate Irradiation Injury
Authors: Miller William R. , McDonald Roy E.
Published: February 2019

`Marsh' white grapefruit (Citrus paradisi Macf.) harvested from exterior canopy positions were less tolerant of 0.5 or 1.0 kGy irradiation than were interior fruit. Irradiation at 0.0, 0.5, or 1.0 kGy resulted in 0.0%, 24.3%, and 37.5% surface pitting of fruit, respectively. Pitting was reduced 30% by temperature conditioning with vapor heat at 38 or 42 °C for 2 hours. Exterior canopy fruit had ≈2-fold more pitting, had greater weight loss, and were firmer than interior canopy fruit. Fruit weight loss increased and firmness decreased as conditioning temperature and irradiation dose increased. Total soluble solids, titratable acidity, and flavor decreased with increasing irradiation dose. The peel of exterior canopy grapefruit was damaged more by irradiation than was that of interior fruit, but irradiation damage was reduced by temperature conditioning.
Fermentative Volatile Production in Relation to Carbon Dioxide-induced Flesh Browning in `Fuji' Apple
Authors: Volz Richard K. , Biasi William V. , Mitcham Elizabeth J.
Published: February 2019

Apple (Malux ×domestica Borkh., cv. Fuji) fruit were harvested from two California orchards 190 and 210 days after full bloom and from an additional three orchards at 190 days after full bloom. Fruit were immediately exposed to 20 or 50 kPa CO2 in air at 20 °C. Area of flesh browning and tissue ethanol, acetaldehyde, and ethyl acetate concentrations for individual fruit were determined immediately before exposure and after 3 and 7 days (20 kPa) or 1 and 3 days (50 kPa) exposure to CO2. Area of flesh browning and concentrations of all compounds increased with increasing duration of exposure to high CO2, were greater in response to 50 kPa than to 20 kPa CO2, and were greater for fruit harvested later in the season. For individual orchards and for individual fruit within most orchards, greater flesh browning was associated with higher acetaldehyde concentrations after 7 days exposure to 20 kPa CO2 or 3 days exposure to 50 kPa CO2. Similarly, flesh browning was positively correlated with ethanol concentrations after 7 days at 20 kPa CO2, but was not related to tissue ethyl acetate concentrations at either CO2 partial pressure. However, higher production of ethanol, acetaldehyde, or ethyl acetate relative to flesh browning occurred during exposure to 50 kPa than to 20 kPa CO2. This suggests that the relationship between accumulation of these compounds and CO2-induced flesh browning in `Fuji' is not simply causal.
Polyembryony in Mango (Mangifera indica L.) Is Controlled by a Single Dominant Gene
Authors: Aron Y. , Gazit S. , Czosnek H. , Degani C.
Published: February 2019

The segregation pattern of individuals originating from selfing of several monoembryonic cultivars and one polyembryonic line indicated that polyembryony in mango was of genetic nature. All the plants originating from monoembryonic cultivars bore monoembryonic fruits. A one-monoembryonic to three-polyembryonic segregation pattern was observed among individuals originated from the polyembryonic line, indicating that polyembryony in mango is under the control of a single dominant gene.
1-Methylcyclopropene Can Differentially Affect the Postharvest Life of Strawberries Exposed to Ethylene
Authors: Ku V.V.V. , Wills R.B.H. , Ben-Yehoshua S.
Published: February 2019

Strawberry (Fragaria ×ananassa Duch.) fruit were fumigated for 2 hours at 20 °C with 1-mcp at concentrations from 5 to 500 nL·L-1, then held at 20 and 5 °C in air containing 0.1 μL·L-1 ethylene. Fumigation with 1-mcp at 5 to 15 nL·L-1 extended the postharvest life by ≈35% at 20 °C and 150% at 5 °C, but at higher 1-mcp concentrations there was an accelerated loss of quality with a 30% to 60% decrease in postharvest life at 500 nL·L-1 at both 20 and 5 °C. Chemical name used: 1-methylcyclopropene (1-mcp).
Bark Anthocyanin Levels Differ with Location in Cultivars of Red Maple
Authors: Sibley Jeff L. , Ruter John M. , Eakes D. Joseph
Published: February 2019

The objective of this study was to determine differences in the bulk anthocyanin content of bark tissue of container-grown red maple (Acer rubrum L. and Acer ×freemanii E. Murray) at two Georgia locations with different environmental conditions. Rooted cuttings and tissue-cultured plantlets of eight cultivars were grown in either Blairsville or Tifton, Ga. [U.S. Dept. of Agriculture (USDA) Hardiness Zones 6b and 8a; American Horticultural Society (AHS) Heat Zones 5 and 8, respectively], from June 1995 until Dec. 1996. Bark tissue from twigs of trees grown in Blairsville was visually redder and contained more total anthocyanin than did that of trees grown in Tifton. Levels of total anthocyanins were higher (P = 0.0007) at Blairsville (0.087 mg·g-1, N = 48) than at Tifton (0.068 mg·g-1, N = 47). At both locations the levels were highest in `Landsburg' (`Firedance'™), followed by `Franksred' (`Red Sunset'™) and `October Glory'. This is the first report to quantify anthocyanin differences in bark tissue of container-grown trees. Cooler nights in Blairsville might have contributed to increased coloration by reducing respiratory losses, thus leaving more carbohydrates available for pigment production.
Correlations between Leaf and Soil Mineral Concentrations and Ginsenoside Contents in American Ginseng
Authors: Li Thomas S.C. , Mazza G.
Published: February 2019

Four-year-old American ginseng (Panax quinquefolium L.) plants and soil samples were collected from nine ginseng gardens. Soil and leaf mineral contents were determined and six major ginsenosides, Rb1, Rb2, Rc, Rd, Re, and Rg1, were extracted from leaves and roots and quantified by high-performance liquid chromatography (HPLC). Correlation coefficients were more significant for soil nutrient levels vs. ginsenoside contents of leaves than of roots, suggesting that soil nutrient levels may play a major role in the synthesis of leaf ginsenosides. Minor elements in the leaf were also better correlated with ginsenoside contents of the root than that of the leaf. Iron content in the leaves exhibited highly significant correlations with the levels of Rb1, Rb2, Rc, and Rd, but calcium and copper contents were negatively correlated with Rg1 in the roots.
Seasonal Patterns of Nutrient and Dry Weight Accumulation in Freeman Maple
Authors: Rose Mary Ann , Biernacka Barbara
Published: February 2019

Seasonal patterns of N, P, and K accumulation and remobilization in Freeman maple (Acer× freemanii E. Murr. `Jeffersred') were studied to guide future improvements in fertilization efficiency. Leaves, stems, and roots of container-grown trees were harvested over a 12-month period (June to June) in each of two experiments. Plants were fertilized from June to October with three rates of soluble fertilizer (50, 100, and 200 mg·L-1 N). Fertilizer rate had linear and quadratic effects on dry weight and nutrient contents, but did not affect seasonal accumulation patterns. Whole-plant nutrient contents and dry weights increased until mid-October, prior to leaf abscission. The largest fractions of nutrients and dry weight were allocated to leaves until early September. Between September and October, the most rapid accumulation of N, P, and dry weight occurred in root tissue. Highest nitrogen recovery efficiency occurred in late summer (Expt. 2) or early fall (Expt. 1). There was no statistically significant evidence for N, P, or K resorption in the fall, but evidence of N (not of P or K) remobilization in the spring was very strong. Whole plant dry weight doubled between April and June, while ≈50% of the N stored in woody tissues was translocated to new shoots.
Prebloom Foliar Boron, Zinc, and Urea Applications Enhance Cropping of Some `Empire' and `McIntosh' Apple Orchards in New York
Authors: Stover Ed , Fargione Michael , Risio Richard , Stiles Warren , Iungerman Kevin
Published: February 2019

This study was initiated to determine if prebloom sprays of B, Zn, and urea would enhance cropping of apple (Malus×domestica Borkh.) after cold injury, hypothesizing that they may accelerate recovery of damaged vascular tissue. The following foliar nutrient treatments were applied prebloom to `McIntosh' and `Empire' trees at two sites in 1994 and 1995: 1) control; 2) B (22.8 mm) at half-inch-green; 3) Zn-EDTA (0.75 mm) at half-inch-green; 4) B and Zn-EDTA at half-inch-green; 5) B, Zn-EDTA, and urea (59.4 mm) at half-inch-green; 6) B and Zn-EDTA at half-inch-green, followed by B, Zn-EDTA, and urea at pink. In 1994, following a very severe winter that caused visible damage to vascular tissue, `Empire' at both sites cropped more heavily following all treatments that included both B and Zn; such treatments increased cropload by an average of 22% and 35% at the two test sites. Despite a mild winter preceding the 1995 season, prebloom nutrient treatments again increased cropping of `Empire'. In 1996, treatments included a control and a single foliar treatment (B + Zn-EDTA at half-inch-green followed by B, Zn-EDTA, and urea at pink) on `McIntosh' and `Empire' at seven orchard sites. Treatment enhanced cropping in `McIntosh' at three of the seven sites, but there was no effect on `Empire'. Factors influencing differences in response were not apparent from this study, although a complex of factors may be involved. Data for all years indicated that prebloom nutrients did not enhance spur leaf development or fruit set; such treatments probably enhance cropping by increasing retention of flower buds that would otherwise abscise before anthesis. Where cropping was increased, mean fruit weight was not reduced at P ≤ 0.05 but fruit weight was significantly less at P ≤ 0.10 in 1995. Chemical names used: boron (Solubor, disodium octaborate tetrahydrate); zinc (Zn-EDTA, zinc chelate).
Distribution of Nutrients in Cut-flower Roses and the Quantities of Biomass and Nutrients Removed during Harvest
Authors: Tamimi Yusuf N. , Matsuyama Dennis T. , Ison-Takata Kimberly D. , Nakano Richard T.
Published: February 2019

Pollution of the environment, especially groundwater, may be reduced by proper fertilizer management, based in part on crop removal. The weights and concentrations of nutrients in tissue components of cut-flower roses (Rosa hybrida L.) were determined to assist in developing a fertilizer management system that sustains a high level of production but also is environmentally friendly. Harvested flower stalks of the cv. Royalty were cut to 45-cm length, and sectioned into 15-cm units, from which blossom, leaf, and stem components were separated, weighed, and analyzed for nutrients. The flower represented 28.5%, leaves 46.0%, and stem 25.5% of the total weight of the stalk. Upper leaves had the highest levels (g·kg-1) of N (29.3), Ca (21.8), and Mg (3.0), and (mg·kg-1) Fe (74) and Mn (71). The flower was highest in K (18.4 g·kg-1), P (3.0 g·kg-1), Zn (29 mg·kg-1), and B (23 mg·kg-1). Annual removal of nutrients by 45-cm flower stalks totaled: 256.2, 187.5, 116.3, 30.0, 26.0, and 21.1 kg·ha-1 of N, K, Ca, P, Mg, and S, respectively. Micronutrients removed per annum totaled 700, 470, 260, 200, and 190 g·ha-1 of Fe, Mn, Zn, Cu, and B, respectively. Assuming 50% recovery of applied N and 80% of K, a total annual application of N at 512 kg·ha-1 and K at 234 kg·ha-1 may replace the amounts removed. However, actual rates of N and K, as well as other nutrients applied, should be adjusted based on soil and tissue analysis results. Removal of nutrients will be greater if stalks harvested are >45 cm in length, which may necessitate additional nutrient application, depending on soil conditions.
Potassium Application Reduces Calcium and Magnesium Levels in Bermudagrass Leaf Tissue and Soil
Authors: Miller Grady L.
Published: February 2019

High rates of potassium (K) are often applied in an attempt to increase stress tolerance of hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy] turfs. Two field-grown bermudagrass cultivars, `Tifdwarf' and `Tifway', were used to determine the influence of applied K on plant nutrient content and nutrient retention in two soils. Six rates of K ranging from 0 to 390 kg·ha-1 were applied twice per month each growing season from 1992 to 1994. The cultivars were established on both a sand-peat (9:1 by volume) and loamy sand. Potassium chloride and K2SO4 were compared as sources of K, and were applied simultaneously with N applications. Extractable soil K and leaf tissue K concentrations increased with increasing K rates. There was a critical K fertilization level (74 to 84 kg·ha-1) for each cultivar and medium combination beyond which no increase in tissue concentration was observed. Increasing K fertilization resulted in a decrease in extractable Ca and Mg in both media with corresponding decreases in tissue Ca and Mg concentrations. High K rates appear to increase the potential for Ca and Mg deficiencies in bermudagrass, indicating that rates higher than those that provide sufficient K levels for normal growth should not be used.
Intercropping Cabbage and Indian Mustard for Potential Control of Lepidopterous and Other Insects
Authors: Bender David A. , Morrison William P. , Frisbie Raymond E.
Published: February 2019

A system of intercropping cabbage (Brassica oleracea var. capitata L.) with Indian mustard [Brassica juncea (L.) Czern.] to reduce pesticide applications was evaluated over three cropping seasons. Insects were monitored in nonintercropped cabbage, cabbage plots surrounded by Indian mustard, and the Indian mustard intercrop. Insecticide applications were made to individual plots based on specific treatment thresholds for lepidopterous insects and accepted pest management practices for other insects. Intercropping had no significant effect on the number of lepidopterous larvae in cabbage. Indian mustard did not appear to preferentially attract lepidopterous insects, but was highly attractive to hemipterans, especially harlequin bugs [Murgantia histrionica (Hahn)]. In one season with heavy harlequin bug pressure, intercropping with Indian mustard eliminated two insecticide applications to cabbage. Intercropping cabbage with Indian mustard does not appear to be an economical pest management practice under normal pest pressures in West Texas.
Susceptibility of Vegetatively Propagated Petunia to Tobamovirus Infection and Its Possible Control
Authors: Cohen J. , Sikron Noga , Shuval S. , Gera A.
Published: February 2019

In this study, 18 Petunia ×hybrida Hort. Volm.-Andr. cultivars were mechanically inoculated with the tobamoviruses tobacco mosaic (TMV) or tomato mosaic virus (ToMV) (20 μg·L-1 in 0.05 m sodium phosphate buffer). One and 2 weeks post-inoculation (PI), inoculated and noninoculated upper leaves were harvested and assayed for TMV infection using enzyme-linked immunosorbent assay (ELISA). Local lesions developed on inoculated leaves of 16 cultivars 3-5 days PI. A total of 11 and 16 of the cultivars developed systemic symptoms characteristic of tobamovirus infection 2 weeks after inoculation with TMV and ToMV, respectively. All cultivars were positive in ELISA tests. Large amounts of virus were recovered from the upper, noninoculated leaves of all cultivars, including symptomless plants. Up to 95% infection by TMV occurred when a sterilized knife was passed through an infected shoot of petunia prior to its being used to remove cuttings from healthy petunia plants. Heat sterilization of knives and/or treatment with 2.8 g·L-1 sodium troclosene was very effective in controlling TMV transmission.
A Simple Pythium aphanidermatum Field Inoculation Technique for Perennial Ryegrass
Authors: Feng Yan , Dernoeden Peter H. , Grybauskas Arvydas P.
Published: February 2019

A simple field Pythium inoculation technique is needed to be able to assess cultivars for disease resistance and effectiveness of cultural practices or fungicides in the management of Pythium blight. We assessed two mixtures as inocula [i.e., an infested tall fescue (Festuca arundinacea Schreb.) seed plus wheat (Triticum aestivum L.) bran and an infested rye (Secale cereale L.) plus barley (Hordeum vulgare L.) grain mix], and three covers (black and clear plastic, and a geothermal blanket) for their ease of use and consistency in producing Pythium blight epidemics in perennial ryegrass (Lolium perenne L.) field plots. Both the fescue seed-wheat bran and rye-barley grain inocula provided good media on which to culture Pythium aphanidermatum (Edson) Fitzp. In general, the fescue-wheat bran mix applied at the high level (100 mL/0.9-m2 plots) produced greater blight ratings in perennial ryegrass than did the low level (50 mL/0.9-m2 plot). The fescue-wheat bran also was generally more effective than either rate of the rye-barley mix in blighting turf. All covers enhanced blighting, when compared to the uncovered control, by raising the relative humidity. Covering plots with black plastic following inoculation resulted in greater blight ratings than did covering with either clear plastic or the geothermal blanket.
Methyl Jasmonate Promotes Apple Fruit Degreening Independently of Ethylene Action
Authors: Fan Xuetong , Mattheis James P.
Published: February 2019

Climacteric `Fuji' apples (Malus ×domestica Borkh.) were treated with water, 0.45 mmol·m–3 1-methylcyclopropene (MCP), 2 mmol·L–1 methyl jasmonate (MJ), or both MCP and MJ. Fruit were kept at 20 °C for 17 days after treatment. Ethylene production, respiration, and color change were all inhibited following MCP treatment. Ethylene production following MJ treatment fluctuated below and above that of controls, but was representative of postclimacteric apples at all times. Rates of respiration and color change were enhanced by MJ, even when fruit were previously treated with MCP. The results indicate that MJ can enhance rate of color change and respiration in apple fruit independently of ethylene action.
Nonmelting-flesh Trait in Peaches Is Not Related to Low Ethylene Production Rates
Authors: Brovelli Ernesto A. , Brecht Jeffrey K. , Sherman Wayne B. , Sims Charles A.
Published: February 2019

The notion that ethylene production levels in nonmelting-flesh (NMF) peach (Prunus persica L.) fruit are normally lower than those in melting-flesh (MF) fruit is refuted in our study. In fact, NMF fruit (`Oro A' and FL 86-28C) usually produced higher levels of ethylene than did MF fruit (FL 90-20 and `TropicBeauty'). In both MF and NMF peaches, the rate of ethylene production, rather than the respiration rate, provided a good indication of the developmental stage of the fruit at harvest. Ethylene content in fruit on the tree followed a climacteric pattern, with the level in `Oro A' (NMF) and FL 90-20 (MF) peaking at 50 and 12 μL·L–1, respectively. The respiratory climacteric was not apparent in either `Oro A' or FL 90-20, and levels of CO2 were similar in both genotypes.
Comparison of Leaf Disk, Greenhouse, and Field Screening Procedures for Evaluation of Grape Seedlings for Downy Mildew Resistance
Authors: Brown Maurus V. , Moore James N. , Fenn Patrick , McNew Ronald W.
Published: February 2019

This research was conducted to compare an in vitro leaf disk technique with greenhouse and field evaluations for screening large populations of grape (Vitis sp.) seedlings for downy mildew (Plasmopara viticola Berk. & Curt. Berl. & de Toni) resistance. Seedlings produced by crossing resistant × resistant, resistant × susceptible, and susceptible × susceptible parents were rated for sporulation, chlorosis, and necrosis. Leaf disk sporulation ratings at the first and second rating were highly correlated with the second sporulation rating in the field. Necrosis ratings from the leaf disk evaluations were significantly correlated with field necrosis ratings, but leaf disk chlorosis ratings were not correlated with field ratings. Some correlations, including evaluations of chlorosis, between the greenhouse and field ratings were highly significant. Seedling ratings of 0 or 1 for sporulation, chlorosis, and necrosis in the leaf disk assay agreed with field evaluations 85.6% of the time vs. 80.3% agreement between greenhouse and field ratings. Sporulation was the parameter most highly correlated between leaf disk or greenhouse and field evaluation of resistance. The leaf disk procedure appeared to be a good predictor of field resistance, and is more practical than the greenhouse method for screening large populations.
091 Cytogenetics of Inland Saltgrass
Authors: Reid Scott , Harrington Judy , Hughes Harrison
Published: February 2019

Inland saltgrass, Distichlis spicata var. stricta (Torr.) Beetle, is a native western U.S. grass that has potential in turf situations. Elite clones with outstanding potential have been selected. Poor seed production appears to be the main limiting factor for its use as turf in saline conditions. In order to better understand seed set, 40 genotypes were examined for chromosome number and morphology. Chromosome numbers of root tip metaphase spreads varied with the most common being 2n = 38. However, chromosome numbers of 39, 40, 42, and 74 were also observed. Meiotic examination of anthers revealed 19 bivalents for those with 38 chromosomes while those with 42 had 20 bivalents with 2 unpaired chromosomes. The unpaired chromosomes lagged at anaphase. Crosses among genotypes of different chromosome number have resulted in good seed set. Harvested seed are germinable and plants from these crosses are being grown for further studies.
181 Strawberry Growth and Weed Control in Response to Using Corn Gluten Hydrolysate
Authors: Dilley Craig A. , Nonnecke Gail R. , Christians Nick E.
Published: February 2019

Alternative approaches to strawberry production that rely on cultural practices, biological controls, or natural products to reduce or replace off-farm chemical inputs are needed. Driving this growing interest are environmental concerns and rising production costs. Corn gluten meal (CGM), a byproduct of corn wet-milling, has weed-control properties and is a N source. The weed control properties of CGM have been identified in previous studies. The hydrolysate is a water-soluble, concentrated extract of CGM that contains between 10% to 14% N. Our objective was to investigate corn gluten hydrolysate as a weed control product and N source in `Jewel' strawberry production. The field experiment was a randomized complete block with a factorial arrangement of treatments and four replications. Treatments included application of granular CGM, CGM hydrolysate, urea, urea, and DCPA (Dacthal), and a control (no application). Granular CGM and urea were incorporated into the soil at a depth of 2.5 cm at rates of 0, 29, 59, and 88 g N/plot. Plot size was 1 × 3 m. The field experiment was conducted from 1995-1998. The source of nitrogen showed few effects for all variables measuring yield and weed control for all years. In general, the rate of nitrogen had little or no effect on total yield. However, the rate of nitrogen at 88 g N/plot showed an increase in average berry weight, leaf area, leaf dry weight, and weed control.