bluuebunny/crossref_metadata_2025 huggingface dataset:
Postharvest Quality of Lychee Fruit: Role of Relative Humidity and Panicle
Authors: Vilasachandran T. , Sargent Steven A.
Published: February 2019

Pericarp browning, weight loss, and the associated quality deterioration are the unsolved postharvest problems of lychee (Litchi chinensis Sonn.). Freshly harvested fruits (`Brewster') were stored ± plastic wrap (99% and 84% relative humidity, RH, respectively) and ± panicle at 5°C for 18 days to simulate commercial handling scenarios. There were no significant losses in pericarp color (L*, hue angle, chroma value), total soluble solids, and total sugars from initial values for wrapped fruits. Wrapped lychees were 100% marketable, compared to 17% for unwrapped fruits. The former retained higher weight, moisture content and total titratable acidity (TTA, pulp), and lower pulp pH. Colletotrichum sp., Cladosporium sp., and Alternaria sp. caused decay in 56% of unwrapped fruits, whereas wrapped fruits were free of decay. Fruits with panicles had significantly higher weight loss (3%) than clipped fruits for both wrapped and unwrapped fruits. Pulp TTA tended to decrease and pH to increase more in fruits with panicle. Postharvest quality of lychee fruits was significantly extended by removing the panicle and maintaining nearly saturated RH during handling and storage.
Antioxidant Potential and Strawberry Preservation
Authors: Hébert Claire , Willemot Claude
Published: February 2019

Plant antioxidants have gained considerable interest because of their importance for the preservation of produce and also because of their therapeutic properties. There is increasing evidence that these compounds protect plant tissues from stress and that they delay senescence. Seven strawberry cultivars were analyzed to investigate the possible relationship between their antioxidant potential and fruit shelf-life. The antioxidant defense systems studied were free radical scavenging enzymes (SOD, catalase, glutathione reductase, GSH, ascorbate peroxidase, ascorbate free radical reductase), ascorbic acid, and ellagic acid. Enzyme assays were performed using spectrophotometric kinetic measurements. Ascorbic acid and ellagic acid were determined by HPLC. The antioxidant potential of the tissues had an incidence on fruit quality and shelf-life. The impact of these antioxidative parameters will be discussed with respect to breeding criteria for reduced perishability of strawberries.
Determination of Maximum Maturity for Stone Fruit
Authors: Crisosto Carlos H. , Slaughter David , Johnson R. Scott , Cid Luis , Garner David
Published: February 2019

Maximum maturity indices for different packinghouse conditions based on cultivar critical bruising thresholds and bruising potentials were developed for stone fruit cultivars. The critical bruising thresholds, based on fruit firmness, and the bruising probabilities varied among stone fruit cultivars. In general, plums tolerated more physical abuse than yellow-fl esh peach, nectarine, and white-flesh peach cultivars. Impact location on the fruit was an important factor in the determination of critical bruising thresholds. Potential sources of bruising damage during fruit packing were located using an accelerometer (IS-100). A survey of different packinghouses revealed that bruising potentials varied from 21 to 206 G. Bruising potential was reduced by adding padding material to the packinglines, minimizing height differences at transfer points, synchronizing timing between components, and reducing the operating speed. Bruising probabilities for the most-susceptible California-grown cultivars at different velocities and Gs have been developed. Development of a practical sampling protocol to determine fruit firmness during maturation was studied.
Enhanced Resistance to West Indian Sweetpotato Weevil (Euscepes Postfasciatus) in Transgenic `Jewel' Sweetpotato with Cowpea Trypsin Inhibitor and Snowdrop Lectin
Authors: Golmirzaie A. , Zhang D.P. , Nopo L. , Newell C.A. , Vera A. , Cisneros F.
Published: February 2019

Euscepes postfasciatus is one of the most important sweetpotato pests in the South Pacific, Caribbean basin, and some countries of Central and South America. Development of host resistance will greatly improve the effects of integrated pest management (IPM) for this pest. Ten transgenic clones of `Jewel' sweetpotato with cowpea trypsin inhibitors and snowdrop lectin, developed by Axis Agri. Genetics, Ltd., were assayed for weevil resistance using a no-choice bioassay. A replicated experiment was conducted in the screenhouse. Five storage roots from each clone were infested with five pairs of adults. Non-transformed `Jewel' was used as a check. Resistance was assessed 60 days after infestation by estimating the percentage of internal damage and the weevil population in the storage roots. A five-grade damage index was recorded. The experiment was repeated twice. Significant enhancement of resistance was found in the transgenic clones. Clone CTI-13 with cowpea trypsin inhibitor and clone PCG-7 with both cowpea trypsin inhibitor and snowdrop lectin demonstrated moderate resistance to E. postfasciatus, whereas the non-transformed `Jewel' was susceptible. This result shows that resistance to Euscepes postfasciatus can be achieved through genetic transformation.
Effectiveness of Different Applications of Imidacloprid for the Control of Sweetpotato Whitefly and Muskmelon Yield
Authors: Farias-Larios J. , Orozco M. , Guzman S. , Gutiirrez A.
Published: February 2019

Sweetpotato whitefly (Bemisia tabaci Gennadius) is one of the serious pests on cucurbits and causes injury by sucking sap and by the transmission of virus. In Western Mexico, melon and other vegetable crops have been subjected to losses as a results of whitefly feeding and whitefly-transmitted virus infection. Traditional control is based in the Metamidophos and Endosulfan applications (more than 10 times). Recently, Imidacloprid has been reported as new alternative to whitefly control. Thus, this study was conducted to determine the effect of Imidacloprid under different applications methods on sweetpotato whitefly populations and cantaloupe yield. Ten treatments were evaluated: 1) seed + basal stem, 2) seed + soil at 8 cm, 3) seed + soil (near to seed), 4) seed + soil (seedlings emergence), 5) seed only, 6) basal stem, 7) soil (plant emerged), 8) foliage, 9) Metamidophos and Endosulfan (regional application), and 10) control, without application. These were arranged in a randomized complete-block design with four replications. Each replication had four beds 7.5 m long. Number of whitefly adults was determined weekly on 24 plants selected at random for each treatment (two leaves/plant). At 22, 39, 57, and 73 days after showing, the whitefly nymphs/cm2 were also counted. Imidacloprid applied to foliage five times showed the best whitefly control during the entire crop season, reducing injury and increasing melon yield at 1346.7 cartons/ha, while Metamidophos and Endosulfan showed an intermediate effect (1073.6 cartons/ha).
Effects of Ovipositional Preference on Distribution of the Xylophagous Leafhopper, Homalodisca coagulata (Say)
Authors: Andersen Peter C. , Brodbeck Brent V. , Mizell Russell F.
Published: February 2019

Homalodisca coagulata (Say) is a xylem-feeding leafhopper that is the principal vector of many economically important diseases resulting from infection by Xylella fastidiosa (i.e., plum leaf scald, phony peach disease). We have previously established that high abundances and high consumption rates of H. coagulata occur on host species with high amide concentrations in the xylem fluid. Several lines of research suggest that selection of “marginal hosts” (those that typically have low abundances of leafhoppers) may be influenced by ovipositional, as well as feeding, preferences. In northern Florida, Euonymus japonica consistently has the highest densities of eggs and young nymphs, but is only a marginal host for adults. Adults caged on this host feed little and have a short longevity. In contrast, young insects (second instar) caged on the host have high survivorship rates and assimilate dietary nutrients with high efficiency. H. coagulata are abundant on Prunus germplasm in northern Florida during the month of June, but only occasionally visit Prunus after this period. In a study of 10 Prunus scion/rootstock combinations, we established that abundances of H. coagulata on Prunus during the peak period were correlated to leafhopper consumption rates. During summer, when Prunus serves as a marginal host, leafhopper abundances are tightly coupled to fecundity rates. Understanding of ovipositional preference may be central to our understanding of Xylella acquisition. These preliminary experiments suggest that leafhoppers may sample xylem fluid during ovipositional selection, as they preferentially select ovipositional sites that have proper nutrient profiles for development of young nymphs (“mother knows best”). Although consumption rates are low for marginal hosts, repeated probing for ovipositional preference may contribute to the spread of diseases caused by X. fastidiosa.
Effect of Hydrogen Cyanamide on Bloom Date, Quality, and Yield of `Kerman' Pistachios on Three Different Rootstocks
Authors: Ferguson Louise
Published: February 2019

Hydrogen cyanamide (H2CN2) has been shown to effectively substitute for lack of chill in a number of species. A 2% H2CN2 solution was applied 24 Feb. 1996 to 24 female Pistacia vera cv. Kerman trees, 6 each on P. atlantica, P. integerrima, and P. atlantica × P. integerrima, hybrid after a season of inadequate chill (<600 hours < 0.5°C). The trees on Atlantica rootstocks were unaffected by the H2CN2 application. Trees on the other two rootstocks produced significantly higher yields after treatment with H2CN2. The primary effect of the H2CN2 appears to have been to significantly decrease the percentage of blank (empty) nuts.
Growth and Development Responses of Flowering Cabbage and Kale Cultivars to Four Growth Retardants
Authors: Carter Johnny , Singh B.P. , Whitehead W.
Published: February 2019

During the fall of 1993 and 1994, four commonly used growth retardants (B-nine, Cycocel, A-rest, and Bonzi) were compared for their effect on the growth and development of three ornamental flowering cabbage cultivars (white, red, and pink) and two ornamental flowering kale cultivars (frizzy red and red peacock). Two weeks after transplanting, seedlings of each cultivar were sprayed with aqueous solutions of the four growth retardants. Treatments for each cultivar were arranged in a randomized complete block design with 6 replications. Plant height, plant width, and dry weight were the parameters used to measure growth and development. Treatments for each cultivar were rated for head formation and color development. Results showed that all the growth retardants except for Cycocel significantly affected growth and development without any effect on head formation and color development. Bonzi caused the greatest growth suppression.
Chrysanthemum Cultivars Differ in Response to Photoperiod when Grown under Far-red Absorbing Filters
Authors: McMahon M.J.
Published: February 2019

Two chrysanthemum [Dendranthema × grandiflorum (Ramat) Kitamura] cultivars, Bright Golden Anne and Spears, were grown in unfiltered sunlight (control) or under filters that removed far-red (FR) light under long- or short-day photoperiods for a total of four treatments. Eight plants from each cultivar were exposed to each treatment. Tips of lateral branches were harvested every 3 days and preserved in formalin, acetic acid, 70% ethyl alcohol (5:5:90 by volume), then observed and photographed under a dissecting microscope. In `Spears', all short-day treatments developed floral primoridia at the same time and rate and the development was normal. Under long days and under FR-absorbing filters, floral primordia initiated and developed normally, but was delayed several days compared to short days. Plants under long days and control filters also developed normal primoridia, but at a slower rate than any of the other treatments. In `Bright Golden Anne', only short-day treatments developed normal floral primordia. Development was the same regardless of filter. Under long days, plants under FR-absorbing filters eventually initiated floral primordia, but development was abnormal. No floral primordia developed under long-day and control filter conditions. In all cases, `Spears' primoridia development was much more rapid than `Bright Golden Anne'.
Improving Fuchsia Cutting Performance by Grafting
Authors: Napier D.M. , McMahon M.J.
Published: February 2019

Increased sales have demonstrated a demand for certain popular cultivars of fuchsia. One of the difficulties in meeting the demand for some of these cultivars has been a low production of cuttings. Grafting was investigated as a means to improve cutting production and performance. Tip cuttings of the poor producer `Little Beauty' were grafted as scions to unrooted cuttings from the more-vigorous cultivars `Beacon' and `Dollar Princess', both known to have very well-developed root systems. `Black Prince', another poor producer with a weak root system, was likewise grafted to unrooted cuttings of the cultivar `Gartenmeister', another cultivar with a vigorous root system. The grafted cuttings were placed in a white poly tent on the greenhouse bench for 7 to 10 days for the graft union to heal and then placed under mist with bottom heat until roots formed. Controls were cuttings from ungrafted plants of the poor producers and autografts of the poor produceers. Cuttings grown from grafted plants of `Little Beauty' on `Beacon' or `Dollar Princess' were »40% larger than cuttings from autografted or nongrafted plants. In the case of `Black Prince' grafted to `Gartenmeister', the resulting cuttings were 100% larger than cuttings grown from autografted or nongrafted plants. The root systems of cuttings from grafted plants developed better than those cuttings from controls.
Characterization of Shade-avoidance in Chrysanthemum and Genetic Transformation with Phytochrome-A from Oat
Authors: Tennessen D.J. , Berlind P.S.
Published: February 2019

Shade-avoidance in plants can result in tall, spindly, and unmarketable plants. Because plant spacing and shade can signal shade avoidance, we grew chrysanthemum (Chrysanthemum grandiflora Ramat, cv. Nob Hill) under two planting densities to characterize the normal plant response to crowding. Plants grew 72 ± 4 cm and developed 17 ± 3 floral branches under 55-cm spacing, while plants grown in close proximity (15-cm centers) grew 78 ± 3 cm and developed 7 ± 1 floral branches under a 12-hour photoperiod. Because phytochrome-A overexpression is known to create dwarf plants, we were interested in transforming `Nob Hill' to alter its phenotype. Sterile leaf and stem cuttings of `Nob Hill' were transformed to express phytochrome-A (Phy-A) from oat (provided by R. Vierstra) using Agrobacterium tumefaciens. The method of Ledger et al. [Plant Cell Reports 10:195 (1991)] was improved when we used internodal segments as described by Yepes et al. [Plant Cell Reports 14:694 (1995)] for a 58% regeneration efficiency. Transformants were screened by selective media and confirmed by southern blots using monoclonal antibodies provided by R. Vierstra. Transgenic and control plants were grown in a greenhouse at 20°C day and 18°C night temperatures with a 14-hour photoperiod. At 4 weeks old, transgenic plants (11 ± 2 cm) were shorter than control plants (15 ± 3 cm). The use of this new transgenic chrysanthemum for high-density mum production is discussed.
Auxins Increase Post-transplant Growth of Vinca
Authors: van Iersel Marc
Published: February 2019

Auxins are commonly used to induce root formation during in-vitro culture of higher plants. Because transplanting is often accompanied by root damage and loss of small roots, auxins also could be beneficial in minimizing transplant shock. Vinca (Cataranthus rosea) seeds were germinated in a peat-lite growing mix and transplanted into pots (55 mL) filled with a diatomaceous earth (Isolite) 10 days after planting. Pots were then placed in a tray containing 62.5 mL of auxin solution per pot. Two different auxins [indole-acetic acid (IAA) and naphtylacetic acid (NAA)] were applied at rates ranging from 0.01 to 100 mg/L. Post-transplant growth was slow, possibly because of Fe+2-deficiencies. Both IAA (1–10 mg/L) and NAA (0.01–10 mg/L) significantly increased post-transplant root and shoot growth. As expected, NAA was effective at much lower concentrations than IAA. At 63 days after transplant, shoot dry mass of plants treated with 0.1 mg NAA/L was four times that of control plants, while 10 mg IAA/L increased shoot dry mass three-fold. High rates of both IAA (100 mg/L) and NAA (10–100 mg/L) were less effective. The highest NAA rate (100 mg/L) was phytotoxic, resulting in very poor growth and death of many plants. These results suggest that auxins may be a valuable tool in reducing transplant shock and improving plant establishment.
Efficacy of Paclobutrazol Drenches on Growth of Potted Sunflowers Grown in 16.5-cm Pots
Authors: Dasoju Shravan K. , Whipker Brian E.
Published: February 2019

Drench applications of plant growth retardant paclobutrazol were applied at 2, 4, 8, 16, or 32 mg a.i./pot, plus an untreated control to pot sunflowers (Helianthus annuus cv. `Pacino') to determine its effect as a chemical height control. All paclobutrazol concentrations applied significantly reduced plant height by »27% when compared to the untreated control, but excessively short plants were observed at 16 and 32 mg a.i./pot. Plant diameter was also significantly decreased by »16% at 2 and 4 mg a.i./pot of paclobutrazol, when compared to the untreated control. Flower diameter decreased by »4% at 2 and 4 mg a.i./pot of paclobutrazol, but only concentrations ≥4 mg a.i./pot were significantly different from the untreated control. Paclobutrazol concentrations had no effect on days from potting to flowering. Drench concentrations of 2 and 4 mg a.i./pot of paclobutrozol produced optimum height control in relation to 16.5-cm-diameter pot size used.
Tissue Specificity of `Chandler' Strawberry Peroxidase Isozymes
Authors: McComb Ellen A. , Miller A. Raymond , Scheerens Joseph C.
Published: February 2019

Peroxidase activity in extracts from freeze-dried tissue of Fragaria × ananassa Duch. cv. Chandler was highest in tissue-cultured (TC) plants, followed by field-grown (FG) and lowest in greenhouse (GH) plants. Among tissue types, activity was highest in petioles, with leaves second highest. Fruit, root, and crown tissue all exhibited low or no activity. When subjected to isoelectric focusing (IEF), petiole tissue extracts exhibited more isozymes than extracts from other organs regardless of staining substrate. Using 4-chloro-1-naphthol and H2O2 as substrates, anionic and cationic isozymes were observed in TC petiole extract with nine isozyme bands ranging in pI from 3.9 to 9.5. In TC leaf extract an isozyme at pI 7.4 was observed that was not present in other organ extracts when H2O2 and benzidine, p-phenylenediamine or 3-amino-9-ethylcarbazole were used as substrates. Specific isozymes and number of isozymes varied according to plant organ and developmental stage. Mature leaves and over-ripe fruit appeared to exhibit more activity and a larger number of isozymes than developing tissues of those plant organs.
Ploidy Levels of Hardy Actinidia Accessions in the U.S. Determined by Flow Cytometry
Authors: Start Mary Ann , Luby James , Guthrie Robert , Filler Debby
Published: February 2019

The hardy Actinidia species represent a source of genetic diversity for improving A. deliciosa (kiwifruit) as well as for creating new economically important cultivars through intra- and interspecific crosses. Attempts at breeding in Actinidia have been complicated by the existence of intraspecific as well as interspecific variation in ploidy. The haploid chromosome number in Actinidia is 29 and diploid (2n=2x=58), tetraploid (2n=4x=116), and hexaploid (2n=6x=174) levels have been identified. Because of the problems encountered when crossing parents differing in ploidy level, it is desirable to know the ploidy levels of plants to be used in breeding. We determined the ploidy levels of 61 Actinidia accessions currently available in the U.S., including primarily accessions of relatively winter-hardy species. The 61 accessions, representing eight species and three interspecific hybrids, were screened for ploidy using flow cytometry. Mitotic root tip cells from one plant from each putative ploidy level were examined microscopically to confirm the ploidy level derived from flow cytometry. There were 17 diploids, 40 tetraploids, and 4 hexaploids. Intraspecific variation was not found among accessions of the species arguta, callosa, deliciosa, kolomikta, melanandra, polygama, or purpurea. All kolomikta and polygama accessions were diploid. All arguta, callosa, melanandra, and purpurea accessions were tetraploid. Actinidia deliciosa was hexaploid. One chinensis accession was tetraploid. Two accessions (NGPR 0021.14 and 0021.3), acquired as chinensis, were hexaploid and may, in fact, be A. deliciosa based on their morphology. `Issai' (arguta × polygama) was hexaploid and `Ken's Red' and `Red Princess' (both melanandra × arguta) were tetraploid.
Healthy, Precocious, and Fertile Hybrids Obtained from Microcitrus spp. (Citrus ichangensis)
Authors: Bowman Kim D.
Published: February 2019

Microcitrus is one of five genera that are partially sexually cross-compatible with the genus Citrus. The genus Microcitrus contains seven species with characteristics that may be valuable for breeding citrus scions and rootstocks, including zygotic embryony, short juvenile period, short fruit maturation time, and resistance to nematodes and Phytophthora. However, relatively few F1 hybrids between Microcitrus and Citrus have been reported, and most of these have been pollen- and ovule-sterile. Some of these intergeneric hybrids have also been highly susceptible to cold damage. To create a genetic bridge for recombination of useful traits from Microcitrus into Citrus, two selections of Citrus ichangensis (an exceptionally cold hardy species with zygotic embryony and short juvenile period) were hybridized with Microcitrus warburgiana and two selections of Microcitrus inodora. Seed were collected from these crosses and germinated in a warm greenhouse. A total of 94 M. inodora xC. ichangensis hybrids and 34 M. warburgiana xC. ichangensis hybrids) were obtained and transplanted to 4-gallon pots in a screenhouse. At 33 months after planting the seed, 42% of the M. inodora × C. ichangensis hybrids and 67% of the M. warburgiana × C. ichangensis hybrids had flowered. Pollen germination tests on agar plates indicated that several hybrids produced large quantities of viable pollen. Numerous crosses were completed using some of these F1 hybrids as pollen and seed parents. Several F1 hybrids were confirmed to be highly fertile by recovery of healthy F2 and backcross hybrids with Microcitrus sp., Citrus sp., Poncirus trifoliata, and other Microcitrus (C. ichangensis) selections.
Nature of Resistance of Pecan Cultivars to Black Pecan Aphids
Authors: Wood Bruce W. , Reilly Charles C.
Published: February 2019

Foliar feeding by the black pecan aphid [Melanocallis caryaefoliae (Davis)] can cause tremendous economic losses. Evaluations of black aphids on pecan genotypes indicates that both antixenosis and antibiosis-like resistance mechanisms exists. Tests for antixenosis indicated that aphids possess clear preferences for certain genotypes over others and that this preference can be dependent on a water-soluble chemical component of the leaf surface. Aphids also exhibited a “conditioning preference,” in which they preferentially feed on genotypes from which they originated. Antibiosis tests indicated that pecan genotypes influence the reproductive success of aphids already possessing a feeding adaptation to those same pecan genotypes; therefore, an evaluation of 30 cultivars for antibiosis indicated that populations developed only 20% as fast on `Choctaw' and `Alley' as on `Desirable' and `Success'. No cultivar was observed to essentially prevent aphid reproduction.
Production of Interspecific Hybrids of Persimmon by Protoplast Fusion
Authors: Tamura Mihoko , Tao Ryutaro , Sugiura Akira
Published: February 2019

Interspecific hybrids between Diospyros glandulosa (2n = 2x = 30) and D. kaki cv. Jiro (2n = 6x = 90) were produced by electrofusion of protoplasts. Protoplasts were isolated from calli derived from leaf primordia, fused electrically, and cultured by agarose-bead culture using modified KM8p medium. Relative nuclear DNA contents of calli derived from fusion-treated protoplasts were determined by flow cytometry. One-hundred-forty-nine of 166 calli obtained had the nuclear DNA content of the sum of those of D. glandulosa and D. kaki cv. Jiro. RAPD analysis showed that the 149 callus lines yielded specific bands for both D. glandulosa and D. kaki cv. Jiro and they appeared to be interspecific somatic hybrid calli. Shoots were regenerated from 63 of the 149 interspecific hybrid calli. PCR-RFLP of chloroplast DNA analysis, flow cytometric determination of nuclear DNA content, and RAPD analysis revealed that the 63 interspecific hybrid shoot lines contained nuclear genome from both the parents but only chloroplast genome from D. glandulosa. Microscopic observation of root tip cells confirmed that somatic chromosome numbers of the interspecific hybrids were 2n = 8x = 120.
Unique Plant Material for Studying Woody-plant Nitrogen Metabolism
Authors: Coleman Gary D. , Black Brent L. , Fuchigami Leslie H.
Published: February 2019

Temperate woody perennials produce proteins in the stem for seasonal nitrogen (N) storage. In Populus species, this seasonal N storage occurs primarily as a 32-kDa Bark Storage Protein (BSP), which can accumulate to 50% of total bark proteins during the winter. Plants of the Populus tremula × Populus alba (clone 717) were transformed with the BSP cDNA in antisense orientation (fused to a constitutive promoter), and regenerated lines were screened. Several independent antisense-BSP (A-BSP) lines were selected, which, after 4 weeks of SD photoperiod, showed 70% to 90% reduction in total BSP accumulation compared to the wild-type (WT). A series of experiments were conducted to compare LD growth of one A-BSP line to that of the WT. A-BSP plants showed reduced growth at both 5 and 50 mM ammonium nitrate fertilization. However, the higher N rate eventually resulted in toxicity in WT, but not in A-BSP plants. A-BSP plants grown hydroponically (0.5x Hoagland1s) showed altered partitioning with reduced stem length and increased leaf area (Leaf:stem dry-weight ratios were 14.8 and 20.9 for ABSP and WT, respectively). Partitioning to the roots was not different between A-BSP and WT. Proposed functions of BSP in seasonal and LD nitrogen metabolism will be discussed.
Effect of Foliar Application of Nitrogen and Sulfur during Flower Bud Formation on Alternate-bearing of Apple Trees
Authors: Izadyar Amir B. , Malakouti Mohammad J. , Talaie Ali R. , Fallahi Esmaeil
Published: February 2019

Different concentrations of urea and ammonium sulfate were sprayed to 15-year-old `Golden Delicious' and `Redspur Delicious' “on” selected apples trees, after 8, 9, and 10 weeks of full bloom. Leaf samples were taken 1 week before and after sprays for protein analysis with Near Infrared Reflectance (NIR). Percentage of flowering and fruit lenght-to-diamater ratio (L/D) were measured in both cultivars. Number of fruit only in `Redspur Delicious' during “on” and “off” years were recorded. Spray of nitrogen and sulfur chemicals increased the leaf protein contents up to a certain extent. Leaf protein content was not significantly affected by spray concentration, time of application, or cultivars. Foliar application of these chemicals at different periods reduced flower density, but did not have a significant effect on fruit L/D ratio. Foliar sprays increased the number of fruits in `Redspur Delicious' in the “on” year, but did not affect different treatments during the “off” year. The sprays after 8, 9, and 10 weeks of full bloom intensified alternate bearing in the following “off” year.
Sugar Metabolism and Relative Enzyme Activities during Fruit Development and Ripening of Papaya
Authors: Zhou Lili , Paull Robert E.
Published: February 2019

This study examined the relationship between the activity of fruit enzymes involved in metabolizing sucrose and sugar accumulation during fruit development, to clarify the role of these key enzymes in sugar accumulation in papaya fruit. Papaya fruit (Carica papaya L. cv. Sunset) were harvested from 14 to 140 days after anthesis (DAA). Fruit dry matter persent, total soluble solids (TSS), and sugar composition and the activity of enzymes: sucrose phosphate synthetase (SPS), sucrose synthetase (SS), and acid invertase were measured. `Sunset' papaya matured 140 days after anthesis during the Hawaii summer season and in about 180 days in cool season on the same plant. Fruit flesh dry matter persent, TSS, and total sugar did not significantly increase until 30 days before harvest. Sucrose synthetase was very high 2 weeks post-anthesis, then decreased to less than one-third in 42 to 56 DAA, then remained relatively low during the rest of fruit development. Seven to 14 days before fruit maturation, SS increased about 30% at the same time as sucrose accumulation in the fruit. Acid invertase activity was very low in the young fruit and increased more than 10-fold 42 to 14 days before maturation. SPS activity remained very low throughout the fruit development and was about 40% higher in mature-green fruit. The potential roles of invertase and sucrose synthetase in sugar accumulation will be discussed.
Reproductive Development in Evergreen vs. Deciduous Blueberry Production System
Authors: Swain Peter A.W. , Darnell Rebecca L.
Published: February 2019

Two cultivars of southern highbush blueberry (Vaccinium corymbosum interspecific hybrid) were grown in containers under the traditional deciduous production system, or the dormancy-avoiding evergreen production system. In the dormancy-avoiding system, plants are maintained evergreen and do not enter dormancy in the winter. This alleviates the chilling requirement, thus extending the potential growing area of blueberries into subtropical regions. Plants in the evergreen production system were maintained in active growth through weekly or biweekly N fertilization (≈21–23 g N/ plant per year). Keeping foliage through the year lengthens the duration of the photosynthetic season of the plant and is hypothesized to improve the carbohydrate (CHO) status of the evergreen plants. This, in turn, may decrease source limitations to reproductive development and potentially increase fruit number and/or size. In both cultivars, the evergreen production system advanced the time of anthesis by 3 to 4 weeks compared to the deciduous production system. Plants in the evergreen system initiated 10% to 25% more flower buds than plants in the deciduous system, depending on cultivar. Average leaf area, leaf fresh weight, total above-ground fresh weight, bud density, and cane length were greater in the evergreen plants than deciduous. The evergreen production system increased plant fresh weight and flower bud number compared to the deciduous system, and may ultimately increase yield.
Gas Exchange and Growth of Selected Transplanted and Nontransplanted Landscape Tree Species
Authors: Montague D. Thayne , Kjelgren Roger , Rupp Larry
Published: February 2019

Gas exchange and growth of transplanted and non-transplanted Acer platanoides `Schwedleri' and Tilia cordata `Greenspire' trees were investigated. This study was conducted on trees planted in 1991 in a field nursery near Logan, Utah. In Spring 1995, three trees of each species were moved with a tree spade to a new location within the nursery and three non-transplanted trees were selected as controls. To simulate landscape conditions, all trees were watered at the time of planting and once per week during the growing season. Pre-dawn water potential, dawn-to-dusk stomatal conductance, mid-day photosynthesis, and growth data were collected over a 2-year period. Transplanted trees of each species were under more water stress (indicated by more negative pre-dawn water potential) than non-transplanted trees. However, pre-dawn water potential of transplanted A. platanoides recovered to near non-transplanted levels, while transplanted T. cordata did not. Dawn-to-dusk studies in 1995 and 1996 showed that stomatal conductance was lower throughout the day in transplanted trees. Once again, transplanted A. platanoides recovered to near non-transplanted levels, while transplanted T. cordata did not. A similar trend for mid-day photosynthesis was found for both species in 1995 and 1996. Transplanted trees of each species had less stem area increase, shoot elongation, and total leaf area than non-transplanted trees for each year. These data indicate that transplanted A. platanoides can recover to near non-transplant pre-dawn water potential and gas exchange levels earlier, and therefore establish faster, than transplanted T. cordata. However, after 2 years neither transplanted tree species were able to fully recover to non-transplanted growth rates.
Do Rhizobia Infect Roots of American Yellowwood and Japanese Pagodatree?
Authors: Foster Carol M. , Graves William R. , Horner Harry T.
Published: February 2019

Knowing whether leguminous trees have the potential to nodulate after infection by rhizobial bacteria is important for managing nitrogen (N) applications during tree production and for culture in the landscape. Although 98% of studied species in the Papilionoideae nodulate, the nodulation status of two tree species in this subfamily is uncertain. Cladrastis kentukea (Dum.-Cours.) Rudd (American yellowwood) did not form nodules during inoculation studies in 1939 and 1992. Nodules were observed on mature Sophora japonica L. (Japanese pagodatree) in Japan and Hawaii in the 1940s, but compatible rhizobia reportedly isolated in Japan are no longer held in bacterial collections. Our objective was to verify further that American yellowwood does not nodulate and to confirm reports that Japanese pagodatree does nodulate. Rhizobia that infect many plant hosts, soil samples and rhizobial isolates from other Sophora spp., and soil samples from mature American yellowwood and Japanese pagodatree were used to inoculate 5-day-old seedlings of American yellowwood, Japanese pagodatree, and control species. Soil from indigenous and introduced trees in the continental United States, Hawaii, Japan, and China was used. Inoculated and uninoculated plants were grown for 7 weeks in sterile Leonard jars or clay pots containing perlite and irrigated with sterile, N-free Hoagland's solution. No inoculation treatment elicited nodulation of American yellowwood or Japanese pagodatree. Our results provide additional evidence that American yellowwood lacks that capacity to nodulate and cast further doubt on nodulation of Japanese pagodatree.
Growth Response of Marigolds (Tagetes erecta `Hybrid Gold') in Mulched Landscape Plantings
Authors: Mirabello R.A. , Einert A.E. , Klingaman G.L.
Published: February 2019

The effects of a mulch material on nutrient availability remain questionable. As organic materials decompose, the increased activity of microorganisms immobilizes nutrients (particularly nitrogen) to preform this process. The decomposition of mulch material and the activity of microorganisms may then compete for nutrients applied to ornamental species in the landscape. To examine this question, four widely available mulch materials (pine bark, cypress pulp, pine straw, and cottonseed hulls) and three fertilizer application methods (granule, liquid, and time release), which were applied either above or below the mulch, were established. Beds with and without mulch cover and no fertilization were established as controls. Marigolds, Tagetes erecta `Hybrid Gold', were planted within the beds. Growth response was found to be greatest in beds with cottonseed hulls. Cottonseed hulls are reported to have a high nitrogen content of their own that may influence less immobilization of nitrogen for decomposition. Beds using pinebark showed significant reduction in plant growth. Fertilization application method also demonstrated significant differences in plant response. The use of a granule fertilizer produced the greatest growth response although initial plant loss was observed in beds using this method. The fast release nature of granule fertilizer and potential toxicity were the suspected reason for this observation. Growth data indicated plant performance was unaffected by fertilizer placement.
Iron Chelate Photodegradation in Fertilizer Solution Affects Foliar Iron and Manganese
Authors: Albano Joseph P. , Miller William B.
Published: February 2019

We have shown previously that Fe-chelates incorporated into soluble fertilizers are vulnerable to photodegradation, and that such solutions can cause modifications in root reductase activity. The objective of this research was to determine the effects of Fe-chelate photodegradation under commercial production conditions. Marigolds were grown in a greenhouse and transplanted stepwise from #200 plug trays to 804 packs to 11.4-cm (4.5-inch) pots. Plants were harvested at the end of each stage, and treatments consisted of either irradiated (complete loss of soluble Fe) or non-irradiated fertilizer solutions ranging from 100-400 mg/L N (0.5–2 mg/L Fe). In the plug and pack stages, foliar Fe was significantly lower and Mn significantly higher in plants treated with the irradiated than nonirradiated fertilizer solutions, averaging 97 μg·g–1 and 115 μg·g–1 Fe, and 217 μg·g–1 and 176 μg·g–1 Mn, respectively. Fe(III)-DTPA reductase activity of roots of plugs treated with the irradiated fertilizer solution was 1.4-times greater than for roots treated with the non-irradiated fertilizer solution. Leaf dry weight in the plug and pack stages was not affected by treatment, and averaged 0.1 g and 1.2 g per plant, respectively.
Onion Yield, Quality, and Storage Responses to Phosphorus and Potassium on a High-phosphorus, Low-pH Muck Soil: Maybe K, but Hold the P
Authors: Evans W.B.
Published: February 2019

The influences of preplant, broadcast P and K fertilizer on long-day yellow onion yield, quality, and storage characteristics were evaluated in 1995 and 1996 on a low-pH muck soil in north-central Ohio. Recommendations based on preseason soil tests indicated the crops would benefit from supplemental K, but not P, in 1995 and also in 1996. In both seasons, broadcast P rates were 0, 67, and 138 kg·ha–1 P2O5; K rates were 0, 168 and 336 kg·ha of K2O. The 3 × 3 factorial of P and K treatments was replicated four times. Phosphorus rate did not significantly influence yield or quality in either 1995 or 1996. Total yield, percent marketable yield, and the concentration of K in the bulbs increased linearly with K in 1995, even though the highest K application rate exceeded the rate recommended by soil testing by more than 100 kg·ha–1. Mean bulb size did not differ significantly among K rates. Potassium rate did not affect yield or quality in 1996, a drier year than 1995. After 5 months of commercial storage, onions from all nine treatments harvested in 1995 had similar amounts of rotten or sprouted bulbs, and weight loss. These results support the idea that P applications can be reduced or eliminated on high-P muck soils without reducing yield or quality. Onion response to applied K requires additional study before firm recommendations can be made.
Evaluation of the Response to Water in Olive
Authors: Fontes Adán Fimbres , Contreras Raúl Leonel Grijalva , Contreras Fabian Robles , Ainza J.A. Cristobal Navarro
Published: February 2019

The area of olives in the region of Caborca has been increasing in the past years to 4500 ha. Olives in other regions do not need the application of water, but,at Caborca, evaporation is greater than rainfall. Because of this, an experiment was conducted in 1992 in which the main objective was to determine the optimum water requirements for olives (table olives). The results indicated that the greatest yield (42.72 kg/tree) was with 35% of the available moisture (AM) in the soil and the lowest yield (24.27 kg/tree) was with 10% of the available moisture in the soil. The total water applied with the 35% of the AM was 197 cm (1.97 m).
IBA and Environment Affect Rooting of Cotoneaster Cuttings
Authors: Khatamian Houchang , van der Hoeven G.A.
Published: February 2019

Softwood cuttings of Cotoneaster multiflorus Bunge were collected on 11 June 1996 from a large specimen shrub located at Manhattan, Kan. Uniform cuttings 12 to 15 cm long were dipped in 0, 5000, 10,000, 15,000, or 20,000 ppm IBA solution for 10 sec and Hormodin™ #2. Cuttings were stuck in a rooting mix consisting of 30% Canadian sphagnum peat and 70% perlite (v/v). The experiment was conducted in a greenhouse either equipped with a fog generator (Humidifan, turbo XE 1000) or the conventional intermittent mist system. The fog generator and the mist system were operated for 12 hr/day. On 12 Aug.1996, the experiment was terminated and cuttings were evaluated for percent rooting. Cuttings treated with 5000 ppm IBA rooted 100% either under mist or with the fog system. Twelve percent of the cuttings under mist rooted when treated with no IBA or Hormodin™ #2, as compared to 50% and 40% under fog, respectively. The rooting quality under the fog system was better than the mist. Rooted cuttings were potted in 15-cm plastic containers filled with Metro Mix™ 702 and were grown under standard greenhouse environment for several weeks prior to planting outdoors.
Genetic Study of Cold Hardiness in Rhododendron Populations
Authors: Lim Chon C. , Arora Rajeev , Krebs Stephen L.
Published: February 2019

Few genetic studies have been conducted on the inheritance of cold hardiness (CH) in woody plants. An understanding of the genetic control of CH can greatly assist the breeder in reducing winter injury. This study was initiated to evaluate the distribution of CH phenotypes in segregating populations of evergreen rhododendrons. Naturally acclimated leaves from individual plants (parents, F1 and 47 F2 progeny) were subjected to controlled freeze–thaw regimes. Using slow cooling rates, leaf discs were cooled over a range of treatment temperatures from –10°C to –52°C. Freezing injury of leaf tissue was assessed by measuring ion-leakage and non-linear regression analysis (data fitted to Gompertz functions) was used to estimate Tmax, the temperature causing the maximum rate of injury. Tmax for the parent plants (R. catawbiense & R. fortunei) and the F1 cultivar Ceylon, were estimated to be –51.6°C, –30.1°C, and –40.4°C, respectively. CH estimates among F2 progeny (Ceylon, selfed) were normally distributed from –14.8°C to –41.5°C, with mean of –27.6°C. Most F2 progeny were less cold-hardy than the tender parent, R. fortunei. The apparent reduction in F2 CH may be caused by the differences in age between the parents (20-year-old mature plants) and F2 progenies (3-year-old juvenile seedlings). Currently, we are testing age-dependent CH responses in rhododendrons, and are also characterizing CH distributions in a backcross population.
Effect of Abscisic Acid on Nitrogen Mobilization, Dormancy, and Cold Acclimation in Apple Trees
Authors: Guak Sunghee , Fuchigami Leslie H.
Published: February 2019

Spring-grafted potted `Fuji'/M26 apple (Malus domestica Borkh.) trees were fertigated with Plantex (20N–10P–20K) weekly until 28 Aug., and sprayed with 1000 ppm abscisic Acid (ABA) two times at 5-day intervals in early September. Nitrogen concentrations of leaves, bark, wood, and root tissues were analyzed using near-infrared reflectance (NIR) spectroscopy at 20to 30-day intervals beginning in August. In general, during leaf senescence, the content of leaf nitrogen decreased and stem nitrogen increased. ABA enhanced leaf senescence and the mobilization of nitrogen from the leaves to the stem tissues. ABA significantly enhanced terminal bud set, endodormancy induction, and cold acclimation. Eventually, the controls attained the similar degree of nitrogen concentration in the stem, terminal bud set, endodormancy, and hardiness.
Feasibility Studies for in Vitro Grafting and Chimera Formation among Lycopersicon spp.
Authors: Stephenson Katherine Kelly , Stommel John R. , Ng Timothy J
Published: February 2019

A protocol was developed to make in vitro graft unions among Lycopercicon spp., and regenerates from cultured graft unions were evaluated for chimera formation. Young seedlings were preconditioned for 4 to 6 days in liquid 1/2-strength Murashige & Skoog (MS) basal medium supplemented with 8.9 μM benzyladenine and 1.0 μM indole-3-butyric acid. Preconditioned seedlings exhibited increased biomass and enhanced graft union survival. In particular, survival of cleft grafts increased from 37% to 95% with the seedling preconditioning. When graft unions among different genotypes were excised from apex-to-apex in vitro cleft grafts and plated on MS basal medium supplemented with 9.1 μM zeatin and 3.9 μM ancymidol, as many as 100 plantlets were regenerated from a single graft union. However, no chimeric regenerates were recovered, indicating that asymmetric responses to grafting may be a limiting factor to in vitro chimera formation.
Inheritance of Resistance to Fusarium oxysporum f. sp. radicus-lycopersici, Causal Organism of Fusarium Crown and Root Rot in Tomato from Lycopersicon pennellii LA 1277
Authors: Scott J.W. , Jones J.P.
Published: February 2019

Lycopersicon pennellii accession LA 1277 was crossed to tomato (L. esculentum) and the F1 was backcrossed to tomato. Self-pollinated seed was saved from backcross plants and seedlings derived were inoculated with Fusarium oxysporum Schlecht f.sp. radicus-lycopersici Jarvis and Shoemaker, the causal agent of Fusarium crown and root rot (FCRR). Seed was saved from resistant plants that were self-pollinated and screened until homozygous resistance was verified five generations after the backcross. Three homozygous lines were crossed to Fla. 7547, a tomato breeding line susceptible to FCRR but resistant to Fusarium wilt races 1, 2, and 3. Subsequently, backcrosses were made to each parent and F2 seed were obtained. The three homozygous FCRR-resistant lines were also crossed to Ohio 89-1, which has a dominant gene for FCRR resistance presently being used in breeding programs. F2 seed were obtained from these crosses. These generations were inoculated with the FCRR pathogen. The resistant parents, F1, and backcross to the resistant parents were all healthy. The backcross to the susceptible parent and the F2 segregated healthy to susceptible plants in 1:1 and 3:1 ratios, respectively. Thus, the resistance from LA 1277 was inherited as a single dominant gene. This gene was different than the gene from Ohio 89-1 because susceptible segregants were detected in the F2 generation derived from the two resistant sources.