bluuebunny/crossref_metadata_2025 huggingface dataset:
Resistance of Daylily Cultivars to the Daylily Rust Pathogen, Puccinia hemerocallidis
Authors: Mueller Daren S. , Williams-Woodward Jean L. , Buck James W.
Published: February 2019

Daylilies (Hemerocallis sp.) have traditionally been considered to be pest-free. However, a rust disease caused by Puccinia hemerocallidis Thüm. has become an increasing problem in the United States since 2000. The objective of this study was to evaluate daylily cultivars for resistance to daylily rust. From a greenhouse evaluation of 84 inoculated cultivars, 14 (17%) were classified as resistant; 13 (15%) were classified as moderately resistant; 22 (26%) were classified as moderately susceptible; and 35 (42%) were classified as fully susceptible. Several cultivars displayed very high levels of resistance and may be utilized by breeders to develop cultivars with improved resistance to daylily rust. Information about the resistance and susceptibility of cultivars also will help commercial growers and gardeners select cultivars that have the potential to dramatically reduce damaging outbreaks of rust.
Applications of Potassium Silicate Decrease Black Spot Infection in Rosa hybrida `Meipelta' (Fuschia Meidiland™)
Authors: Gillman Jeffrey H. , Zlesak David C. , Smith Jason A.
Published: February 2019

Roses in nursery and landscape settings are frequently damaged by black spot, whose causal agent is the fungus Diplocarpon rosae F.A. Wolf. Potassium silicate was assessed as a media-applied treatment for decreasing the severity and incidence of black spot infection. Roses were treated with 0, 50, 100, or 150 mg·L-1 silicon as potassium silicate incorporated into irrigation water on either a weekly or daily schedule. Five weeks after treatments were initiated, plants were inoculated with D. rosae. Roses began to show visual symptoms of infection §4 days later. Roses that had 150 mg·L-1 silicon applied on a daily schedule had significantly more silicon present in their leaves than other treatments as measured by scanning electron microscopy and energy-dispersive x-ray analysis. In addition, roses that had 100 and 150 mg·L-1 silicon applied on a daily schedule had fewer black spot lesions per leaf and fewer infected leaves than any of the other treatments by the end of the experiment 7 weeks later. Although roses treated with higher levels of silicon on a daily basis fared better than roses in the other treatments, all of the roses were heavily infected with D. rosae by the end of the study. The results reported here indicate that using potassium silicate in irrigation water may be a useful component of a disease management system.
Location and Temperature Effects on Soft Scald in `Honeycrisp' Apples
Authors: Tong Cindy B.S. , Bedford David S. , Luby James J. , Propsom Faye M. , Beaudry Randolph M. , Mattheis James P. , Watkins Christopher B. , Weis Sarah A.
Published: February 2019

The effects of growing and storage locations and storage temperature on soft scald incidence of `Honeycrisp' apples were examined. In 1999 and 2000, fruits were produced at five different locations, harvested at two different times, and stored at two or five different storage locations. In 1999, fruits were stored at 0 or 2 °C. Soft scald was only observed in fruits from one growing location and primarily at 0 °C. More soft scald was observed from the second harvest than from the first. Scalded fruits were preclimacteric as determined by ethylene production rate, whereas fruits from the other locations were postclimacteric. In 2000, fruits from four of the growing locations developed soft scald, and soft scald incidence was not related to ethylene production rate. Scalded fruits had higher concentrations of phosphorus, boron, and magnesium, and lower concentrations of manganese than unaffected fruit. Development of soft scald was not related to fruit ethylene production rates, was dependent on growing location, increased with later harvest, and may be related to fruit elemental content.
Characterization of Nutritional Quality of Canola Greens
Authors: Bhardwaj Harbans L. , Hamama Anwar A. , Rangappa Muddappa
Published: February 2019

Lack of adequate processing facilities has been a major hindrance in the adoption of canola (Brassica napus L. and Brassica rapa L.) as an alternative oilseed crop in the southern United States. Therefore, development of alternative uses could be instrumental in facilitating adoption of canola by American farmers. We evaluated chemical composition of greens from four canola cultivars (`Dixie', `Falcon', `HN120-91', and `Jetton') grown during 1995-96 and 1996-97 at Petersburg, Va., to determine their potential as a food and feed source. The results indicated potential yield of ≈11 t·ha-1 of fresh greens and ≈1 t·ha-1 of dry matter. The canola greens contained 3.4% oil and 30.6% protein on a dry weight basis. Canola greens contained 0.52%, 4.14%, 0.35%, 1.59%, and 0.20% (dry weight basis) of phosphorus, potassium, magnesium, calcium, and sodium, respectively. Canola greens also contained 0.94, 2.02, 5.47, 14.65, 28.61, 0.74, and 31.92 (mg/100 g dry weight basis) of sulfur, boron, zinc, manganese, iron, copper, and aluminum, respectively. The oil in canola greens contained 18.79%, 81.14%, 15.36%, and 65.78% saturated, unsaturated, monounsaturated, and polyunsaturated fatty acids, respectively. Based on these values, canola greens compared favorably with mustard and turnip greens.
High Competence for Adventitious Regeneration in the BU-21/3 Melon Genotype Is Controlled by a Single Dominant Locus
Authors: Galperin Marjana , Zelcer Aaron , Kenigsbuch David
Published: February 2019

BU-21/3 is an inbred melon (Cucumis melo L.) genotype that exhibits superior in vitro capabilities for adventitious organogenesis. In order to characterize the inheritance of the regeneration competence in BU-21/3, this line was crossed with PMR45 or `Ananas-Yokneam'—two reticulatus cultivars virtually incompetent for organogenesis. F1, F2, and backcross generations were produced and evaluated for adventitious regeneration competence. Our results indicate that the regeneration trait in BU-21/3 is controlled by a single dominant locus, without cytoplasmic interactions. This locus may become a valuable tool for imperative improvements in future protocols for transgenic breeding of commercial melon genotypes.
Evaluation of Rubus leucodermis Populations from the Pacific Northwest
Authors: Finn Chad , Wennstrom Kirsten , Link Janessa , Ridout Jill
Published: February 2019

Sixteen western black raspberry (Rubus leucodermis Douglas ex Torrey & A. Gray) populations, collected from through out the Pacific Northwest, and `Munger', the most widely grown black raspberry (R. occidentalis L.) cultivar, were established in 1994 in a replicated trial in Corvallis, Ore. In 1996 and 1997 the seedlings were evaluated for date of budbreak, flowering date, ripening date, fruit size, and disease tolerance. Fruit within a replication were pooled for evaluation of pH, soluble solids, titratable acidity, and anthocyanin content. The plants were vigorous and had produced solid hedges by the time evaluation commenced. The populations were significantly different within each year for all traits except for anthocyanin content in 1996. Rubusleucodermis populations were identified that broke bud and ripened fruit earlier or later than `Munger'; however, all flowered with or sooner than `Munger'. Despite the fact that R. occidentalis is native to eastern North America and R. leucodermis to the West, `Munger' was much less affected by foliar and cane diseases than the R. leucodermis populations. Several populations were as vigorous as `Munger'. `Munger' had fruit that were 30% larger than the mean for any R. leucodermis population. Generally, R. leucodermis had higher pH and lower titratable acidity than `Munger', but many populations had similar soluble solids; lower acidity may partly explain the blandness of R. leucodermis fruit compared with `Munger'. Despite the lighter appearance of R. leucodermis, the anthocyanin levels of some populations were higher than `Munger'. Rubusleucodermis may be a source of earlier fruiting, later budbreak, and vigor when used in breeding but careful selection for fruit size (for the fresh market), acidity (for the processing market), and disease resistance must be done. Rubus leucodermis may also be an excellent source of raspberry bushy dwarf virus (RBDV) resistance in black and red raspberry breeding programs.
Characterization of 11 Juglandaceae Genotypes Based on Morphology, cpDNA, and RAPD
Authors: Orel G. , Marchant A.D. , McLeod J.A. , Richards G.D.
Published: February 2019

The interspecific and intergeneric relationships of eight species of Juglans (walnuts) and three other members of Juglandaceae were investigated. The following species were included: the American J. australis Griseb., J. neotropica Diels., J. olanchana Standl. et L.O. Williams, J. nigra L., and Carya illinoensis (Wang.) K. Koch.; two Juglans from South China, namely, J. sigillata Dode and an unidentified J. sp; an Engelhardia also from China and the Asian J. ailantifolia Carr., Pterocarya stenoptera var. tonkinensis Franchet and the Eurasian J. regia L. Cladistic analysis of 27 multistate morphological characters showed that the juvenile J. ailantifolia possessed similar physical traits to that of the juvenile American Juglans species. The chloroplast DNA in the trnL-trnF region indicated a close relationship between Juglans species. Pterocarya put the root of the cpDNA network among the American species. RAPD analysis was performed using eight primers. A total of 138 fragments were generated but only 78 clearly defined bands were used in the analysis. All the DNA data grouped the tropical/subtropical American Juglans with J. nigra, and the two new Asian species with J. ailantifolia and J. regia. The American species were closely related, more so than their Asian counter parts. The closeness of the investigated species predicts interspecific graft compatibility not only within the Asian and American groups, but also between them.
Germination, Emergence, and Seedling Growth of Tomato and Impatiens in Response to Seed Treatment with Paclobutrazol
Authors: Still Jennifer R. , Pill Wallace G.
Published: February 2019

Seed treatments with paclobutrazol (PB), a triazole growth retardant, were examined for seedling growth suppression without exerting a deleterious effect on germination or emergence. Seeds of `Salmon Picotee impatiens (Impatiens wallerana Hook f.) and `Marglobe tomato (Lycopersicon esculentum Mill.) were soaked for 24 or 48 hours at 22 °C in 0, 50, 500, or 1000 mg·L-1 PB or were primed in polyethylene glycol 8000 or grade 5 exfoliated vermiculite (both at -1.0 MPa for 7 days at 22 °C) containing these PB solutions. Any PB seed treatment of impatiens (including a series of lower concentrations up to 50 mg·L-1 PB) that elicited seedling growth suppression also reduced germination and emergence. For tomato, soaking seeds for 24 hours in up to 1000 mg·L-1 PB had little or no effect on germination or emergence, and yet shoot height or dry weight was not decreased further by exceeding 50 mg·L-1 PB. At any PB concentration, soaking seeds for 48 hours or priming seeds resulted in lower percentage of germination or emergence than soaking seeds for 24 hours. Soaking tomato seeds in 50 mg·L-1 PB for 24 hours resulted in similar shoot growth suppression until at least 31 days after planting as a growth medium drench (1 mg·L-1 PB) or as a shoot spray (10 mg·L-1 PB), both applied at 14 days after planting. Beyond 31 days after planting, however, the latter two treatments gave greater shoot growth suppression than the PB seed soak treatment, which had lost its growth suppressive effect. Chemical name used: (+)-(R*,R*)-[(4-chlorophenyl)methyl]- -(1,1,-dimethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).
Effect of Water Conditioners and Surfactants on Vegetative Growth Control and Fruit Cracking of `Empire' Apple Caused by Prohexadione-calcium
Authors: Schupp J.R. , Robinson T.L. , Cowgill W.P. , Compton J.M.
Published: February 2019

Three experiments were conducted on `Empire' apple (Malus ×domestica Borkh.) to evaluate the effects of hard water, calcium chloride (CaCl2), water conditioners, surfactants, and captan fungicide on the growth reduction and fruit cracking caused by prohexadione-calcium (PC). Two applications of 63 mg·L-1 PC provided season-long growth control in two studies. Adding a water conditioner to PC reduced shoot growth more than an application of PC in hard or soft water in one New York study. Ammonium sulfate (AMS) and Choice were equally effective water conditioners. PC provided no growth control of water sprouts and had no effect on fruit set or yield. PC applied at 250 mg·L-1 reduced fruit size. `Empire' fruit cracking and corking was severe, despite the use of only 63 mg·L-1 PC in two of the three experiments. This damage was exacerbated by the addition of a water conditioner, however AMS applied with a surfactant but without PC had little or no effect on either the severity or extent of fruit injury. In a third experiment, the addition of surfactants, CaCl2, or captan to 250 mg·L-1 PC plus a water conditioner had no effect on the severity of fruit damage. Fruit cracking caused by PC increased preharvest drop in two of three experiments, and increased postharvest rot in the Geneva, N.Y., experiment where fruit were stored prior to grading. Application of PC plus a water conditioner reduced estimated gross return per hectare for `Empire. We conclude that the fruit injury is caused by the formulated PC product itself under certain environmental conditions, and that this product should not be used on `Empire. Chemical name used: calcium 3-oxido-4-proprionyl-5-oxo-3-cyclohexine-carboxylate [prohexadione-calcium (PC)].
Mixtures of Buffalograss and Fine Fescue or Streambank Wheatgrass as a Low-maintenance Turf
Authors: Johnson P.G.
Published: February 2019

We investigated mixtures of buffalograss [Buchloë dactyloides (Nutt.) Engelm. `Texoka' and `Cody'] and fine fescue species (Festuca rubra ssp. rubra L. `Vista', F. ovina var. glauca Lam. `Minotaur', F. rubra ssp. commutata Gaud. `Jamestown II') or stream-bank wheatgrass [Agropyron riparium Scribn. & Smith `Sodar'; syn. Elymus lanceolatus (Scribn. & Smith) Gould subsp. lanceolatus] as a low-maintenance turf with low irrigation requirements and season-long green color and growth. Buffalograss plots in Logan, Utah, were overseeded with fine fescue and streambank wheatgrass at two seeding rates. Plots of fine fescue, wheatgrass, or buffalograss alone were also established. At 50% evapotranspiration (ETo) replacement, fine fescues dominated the mixtures with no differences due to seeding rates. Wheatgrass mixture plots were unacceptable in quality. Buffalograss control plots and mixtures were similar for turfgrass quality in August, and fine fescue controls and mixtures were similar in spring and fall. The mixtures performed well in the low-maintenance turf situation, but dominance of fine fescue over the buffalograss limits the potential of these specific mixtures.
Cultivation and Topdressing Requirements for Thatch Management in A and G Bentgrasses and Creeping Bluegrass
Authors: Stier John C. , Hollman Andrew B.
Published: February 2019

Empirical observations suggest certain new cultivars of creeping bentgrass (Agrostis stolonifera L.) with high shoot density require more intensive topdressing and core aeration to control thatch compared to less dense cultivars such as `Penncross. In addition, a variety of Poa annua var. reptans Hausskn., `DW-184, has recently been released for putting green use but management requirements are undocumented. The objective of our project was to determine the core aeration and topdressing requirements for thatch management of creeping bentgrass cultivars `A-4, `G-2, and `Penncross as compared to `DW-184. Plots were established on a sand-based root zone and maintained as putting green turf for 3 years. A factorial treatment arrangement was used to assess the effects of core aeration and topdressing on thatch, topdressing removal, turf quality, and disease. Both `A-4 and `G-2 produced more organic matter as (thatch/mat) than `Penncross and `DW-184. Grass type, core aeration frequency, and topdressing regime affected the amount of topdressing removed by mowing. An interaction between grass type and topdressing regime showed biweekly topdressing with verticutting resulted in less topdressing removal from all grasses except `G-2 compared to monthly topdressing without verticutting. Since no more than 3% of the topdressing applied was removed from any single treatment, however, the overall impact of grass type, core aeration frequency, or topdressing regime are unlikely to affect turf response. Both `A-4 and `G-2 provided consistently better quality turf than `Penncross or `DW-184 at 3.2 mm mowing height, though `A-4 was more susceptible to dollar spot disease (Sclerotinia homeocarpa F.T. Bennett) than `Penncross or `G-2. Cultivation and topdressing methods for management of `A-4 and `G-2 bentgrasses do not differ substantially from `Penncross or `DW-184 creeping bluegrass.
New Options for Annual Bluegrass Control in Overseeded Bermudagrass Putting Greens
Authors: Toler Joe E. , McCarty Lambert B. , Higingbottom Jason K.
Published: February 2019

Annual bluegrass (Poa annua L.) continues to be a problem in bermudagrass golf greens overseeded with roughstalk bluegrass (Poa trivialis L. `Sabre) due to weed encroachment from adjacent fairways, lack of selective herbicide options, and weed diversity. A 2-year study was conducted on an overseeded `Tifgreen bermudagrass putting green to evaluate effects of herbicide treatments on overseeding and annual bluegrass control. Excellent annual bluegrass control (≥90%) and acceptable turfgrass cover (§70%) was achieved with oxadiazon at 2.2 kg·ha-1 a.i. applied 60 days before overseeding (DBO). Fenarimol (AS) at 4.1 kg·ha-1 a.i. (30 + 15 DBO) followed by 1.4 kg·ha-1 a.i. 60 days after overseeding (DAO) and dithiopyr at 0.6 kg·ha-1 a.i. (60 DBO + 120 DAO) also provided acceptable results. Dithiopyr at 0.4 kg·ha-1 a.i. (30 DBO + 120 DAO), dithiopyr at 0.3 kg·ha-1 a.i. (30 DBO + 30 + 120 DAO), and fenarimol (G) at 2.0 kg·ha-1 a.i. (45 + 30 DBO) followed by 0.8 kg·ha-1 a.i. 60 DAO provided inconsistent annual bluegrass control (55% to 75% in 1999 and 87% to 95% in 2000), but offered acceptable turfgrass cover (§70%) each year. The remaining treatments were generally ineffective and provided <50% annual bluegrass control one or both years. Oxadiazon applied 60 DBO at 2.2 kg·ha-1 a.i. provides an excellent option for annual bluegrass control in overseeded bermudagrass putting greens.
Hydrological Properties of Cork Container Media
Authors: Carmona E. , Ordovás J. , Moreno M.T. , Avilés M. , Aguado M.T. , Ortega M.C.
Published: February 2019

Static hydrological properties [aeration capacity, easily available water, reserve water, water release curves: θv(Ψm), and specific humidity curves] and dynamic hydrological properties (saturated and unsaturated hydraulic conductivity) of sub strates based on industrial cork residue (the bark of Quercus suber L.) and cork compost were studied. Samples of similar granulometry have been used to establish the effect of cork composting on the afore mentioned physical properties. Different models were tested to describe the mechanism of water release from these materials. Van Genuchtens model (Van Genuchten, 1978) was the best fit and produced specific humidity curves that revealed slight differences in the ratio of water capacity function. When cork residues were composted for 7 months, important changes occurred in hydrological properties of the material as it became more wettable. Water retention significantly increased from 45% to 54%, at a potential of 5 kPa, although this did not necessarily result in increased water available to plants. A study of the unsaturated hydraulic conductivity (Kunsat) of these materials revealed a significant de crease in the Kunsat water potential at 0-5 kPa, which corresponds to the range in which the irrigation with these substrates was usually carried out. The long composting process resulted in increased Kunsat between 4 and 5 times that of uncomposted material, which would improve the water supply to the plant.
Using Near Infrared Reflectance Spectroscopy to Evaluate Phosphorus, Potassium, Calcium, and Magnesium Concentrations in Bermudagrass
Authors: Miller Grady L. , Thomas Adam
Published: February 2019

Application of nutrients to correct nutrient deficiencies in turfgrasses are often based on tissue analysis. Previous research has indicated that near infrared reflectance spectroscopy (NIRS) may be useful in tissue nutrient concentration determination since it requires minimum sample preparation and has been a reliable predictor of N concentration. The objective of this study was to evaluate the reliability of NIRS in determining P, K, Ca, and Mg concentrations in bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy]. Tissue samples were collected from Florida golf courses, representing different cultivars grown under various conditions and fertilizer regimes. Tissue samples were analyzed using NIRS and traditional wet chemistry (Mehlich-1 extracts analyzed using inductively coupled argon spectrophotometer) before results were statistically compared. Results from wet chemistry analysis averaged 15% lower than those obtained from NIRS. Although results for certain cultivars and elements were positively correlated (`Tifdwarf' Ca, r2 = 0.72; P < 0.01), precision across all cultivars and nutrients was not sufficient (accounted for only 26% of variability) to indicate that NIRS would be an effective management tool for the elements evaluated in this study.
Yield and Relationships among Head Traits in Cabbage as Influenced by Planting Date and Cultivar. I. Fresh Market
Authors: Kleinhenz Matthew D. , Wszelaki Annette
Published: February 2019

Yield and relationships among head traits were recorded in order to better understand the effects of planting date and cultivar selection on crop quality characteristics and to help increase the efficiency of cultivar development, evaluation, and selection. A total of seven cultivars of fresh market-type cabbage (Brassica oleracea L., Capitata Group) were planted in May and June of 1999 and 2000 at the OARDC Vegetable Crops Research Branch in Fremont, Ohio. Total and marketable yield, head traits (e.g., size, weight, density), and core dimensions were recorded at harvest. Main effects of year (Y), planting date (PD), and cultivar (C) and the Y × C interaction significantly affected seven to 10 of 10 head and core traits. However, the PD × C interaction was significant for head density, the ratio of head polar and equatorial diameter, and core base width. The Y × PD interaction was significant for six of 10 head and core traits. May planting tended to result in greater yield and larger, heavier heads with greater polar/equatorial diameter values relative to June planting. However, head density was unaffected by planting date. The number of head and core traits affected by planting date differed among cultivars. For example, six of 10 head and core traits were significantly affected by planting date in `Cheers' and `DPSX315' while one trait was affected by planting date in `SuperElite Hybrid'. The weight of numerous, individual, market-ready, trimmed heads showed a strong (avg. R2 value = 0.92) quadratic relationship to average head diameter. These data suggest that large-scale germplasm evaluations may benefit by including multiple plantings, as head weight, volume, diameter, and shape were affected by planting date, possibly due to variation in temperature and rainfall patterns. The data also suggest that routine measurement of numerous head traits in the same evaluations may be unnecessary, as selected traits (e.g., diameter and weight, head volume, and core volume) were strongly related.
Plant Canopy Affects Sprinkler Irrigation Application Efficiency of Container-grown Ornamentals
Authors: Beeson Richard C. , Yeager Thomas H.
Published: February 2019

Marketable size plants of sweet viburnum (Viburnum odoratissimum Ker-Gawl.), waxleaf ligustrum (Ligustrum japonicum Thunb.), and azalea (Rhododendron spp. L. `Southern Charm') grown in 11.4-L containers were irrigated with overhead impact sprinklers at container spacings ranging from 0 to 51 cm apart. Water reaching the substrate surface was quantified and the percentage of that applied calculated as percent capture (% capture). Percent capture is defined as the percentage of water falling above the plant within a projected vertical cylinder of a container that reaches the substrate surface. For all species, % capture increased linearly with the decline in adjacent canopy interaction, which results from canopies extending beyond the diameter of a container. Increases in total leaf area or leaf area outside the cylinder of a container, in conjunction with increasing distance between containers, were significantly (P < 0.05) correlated with increases in % capture for ligustrum and viburnum. Increases in % capture partially compensated for decreases in percentage of production area occupied by viburnum containers as distances between containers increased, but not for the other two species. Under commercial conditions, optimal irrigation efficiency would be achieved when plants are grown at the minimum spacing required for commercial quality. This spacing should not extend beyond the point where canopies become isolated.
A Scanner-based Root Image Acquisition Technique for Measuring Roots on a Rhizotron Window
Authors: Dong Shufu , Neilsen Denise , Neilsen Gerry H. , Weis Michael
Published: February 2019

A simple flatbed-scanner-based image acquisition system was developed for the measurement of `Gala'/M9 (Malus ×domestica Borkh.) apple tree root growth in rhizoboxes with a transparent acrylic sheet on one side. A tree was planted in the center of each rhizobox, and a modified flatbed scanner was periodically used to directly capture high-resolution digital images of roots growing against the transparent wall. Total root length in the images was either measured manually, or by computer mouse tracing, or automatically with a computer image analysis system. Correlations were made among the different measurements. High quality root images were obtained with the adapted scanner system. Significant linear relationships were found between manual and computer traced root length measurements (r = 0.99), traced and automatic measurements (r = 0.76) and manual and automatic measurements (r = 0.75). Apple roots appeared on the transparent wall 34 days after transplanting, and grew rapidly thereafter, reaching a maximum on the transparent wall 59 days after transplanting. Our results showed that the use of a flatbed scanner for the acquisition of root images combined with computer analysis is a promising technique to speed data acquisition in root growth investigations.
Response of Bell Pepper Cultivars Near-isogenic for the N Gene to Meloidogyne incognita in Field Trials
Authors: Thies Judy A. , Fery Richard L. , Mueller John D. , Miller Gilbert , Varne Joseph
Published: February 2019

Resistance of two sets of bell pepper [(Capsicum annuum L. var. annuum (Grossum Group)] cultivars near-isogenic for the N gene that conditions resistance to root-knot nematodes [Meloidogyne incognita (Chitwood) Kofoid and White, M. arenaria (Neal) Chitwood races 1 and 2, and M. javanica (Treub) Chitwood] was evaluated in field tests at Blackville, S.C. and Charleston, S.C. The isogenic bell pepper sets were `Charleston Belle' (NN) and `Keystone Resistant Giant' (nn), and `Carolina Wonder' (NN) and `Yolo Wonder B' (nn). The resistant cultivars Charleston Belle and Carolina Wonder were highly resistant; root galling was minimal for both cultivars at both test sites. The susceptible cultivars Keystone Resistant Giant and Yolo Wonder B were highly susceptible; root galling was severe at both test sites. `Charleston Belle' had 96.9% fewer eggs per g fresh root than `Keystone Resistant Giant', and `Carolina Wonder' had 98.3% fewer eggs per g fresh root than `Yolo Wonder B' (averaged over both test sites). `Charleston Belle' and `Carolina Wonder' exhibited a high level of resistance in field studies at both sites. These results demonstrate that resistance conferred by the N gene for root-knot nematode resistance is effective in field-planted bell pepper. Root-knot nematode resistant bell peppers should provide economical and environmentally compatible alternatives to methyl bromide and other nematicides for managing M. incognita.
Filter Paper Type Affects the Morphogenic Programs and Buffers the Phytotoxic Effect of Antibiotics in Chrysanthemum and Tobacco Thin Cell Layers
Authors: da Silva Jaime A.Teixeira
Published: February 2019

Filter paper types significantly affected the growth, development and differentiation of chrysanthemum and tobacco stem thin cell layers (TCLs) from in vitro plantlets. Three different filter paper types, normally with varied uses in plant biology, showed varying morphogenic-altering and antibiotic-buffering capacities. Advantec #2 and Whatman #1 significantly stimulated root, shoot and callus formation while Whatman #3 inhibited them, as compared to TCLs placed directly on agar. Filter paper buffered the phytotoxic effect of antibiotics kanamycin and cefotaxime, substances commonly used in genetic transformation experiments, up to as much as 50%, independent of species or genotype. In both `Lineker' and `Shuhou-no-chikara' chrysanthemum cultivars, Advantec #2 and Whatman #1 filter papers stimulated embryogenesis but in tobacco all three filter paper types significantly reduced embryogenesis and explant survival.
Volatile Differences of Pitted and Non-pitted `Fallglo' Tangerine and White `Marsh' Grapefruit
Authors: Dou Huating
Published: February 2019

Postharvest pitting, which has severely affected citrus quality, can be caused by wax application and high temperature storage. Internal volatile composition of waxed and non-waxed fruit could be an indicator of fruit susceptibility to postharvest pitting. In this study, volatile composition was compared between pitted and non-pitted `Fallglo' tangerines [Bower citrus hybrid (citrus reticulata Blanco × C. reticulata Blanco × C. paradisi Macf.) × Temple (C. reticulata Blanco × C. sinensis L.)], as well as in white `Marsh' grapefruit (C. paradisi Macf.). Pitted fruit had a higher volatile concentration than non-pitted `Fallglo' tangerines or white `Marsh' grapefruit. Concentrations of camphene, ethyl hexanoate, alpha-phellandrene, 3-carene, alpha-terpinene, p-cymene, and limonene were higher in pitted white `Marsh' grapefruit than in those of non-pitted fruit. In `Fallglo' tangerines, higher concentrations of limonene and citronellal were found in pitted fruits than in non-pitted fruit. In peel samples of grapefruit, seven different volatiles (methanol, ocimene, citronellyl acetate, alpha-copaene, trans-caryophyllene, alpha-humulene and valencene) were significantly higher in pitted peel than in non-pitted grapefruit peel. Volatiles, such as limonene could be used to predict peel disorders of white `Marsh' grapefruit and `Fallglo' tangerines during storage.
Influence of Time and Concentration of 1-MCP Application on the Shelf Life of Pear `La France' Fruit
Authors: Kubo Yasutaka , Hiwasa Kyoko , Owino Willis Omondi , Nakano Ryohei , Inaba Akitsugu
Published: February 2019

`La France' pear (Pyrus communis L.) fruit were exposed to chilling temperature (-1 °C) for a week to induce ethylene biosynthesis before they were transferred to 20 °C to allow ripening. On 1, 4, or 7 days after the transfer to room temperature, fruit were treated with 20 μL·L-1 1-MCP for 12 hours. The 1-MCP treatments suppressed ethylene and carbon dioxide production significantly and slowed fruit softening. The shelf life period of fruit with desirable firmness treated with 1-MCP on day 4 was twice that of untreated fruit, with firmness of 1-MCP treated fruit on day 1 being higher than desirable while that of fruit treated on day 7 was lower than desirable. To determine the optimum 1-MCP concentration for treatment, fruit were exposed to 0.01 to 100 μL·L-1 1-MCP 3 days after the transfer to 20 °C. The fruit treated with 1 μL·L-1 1-MCP and less ripened similarly to untreated fruit, having a shelf life of a week. 1-MCP treatments of 10 and 100 μL·L-1 inhibited ethylene and carbon dioxide production, and delayed fruit softening and occurrence of senescent break down. The flesh firmness of these fruit maintained suitable eating quality for more than 3 weeks. Our results indicate that 1-MCP treatment of 10 μL·L-1 at 20 °C 3 to 4 days after initiation of ripening can extend the shelf life of `La France' pear fruit. Chemical name used: 1-methylcyclopropene (1-MCP).
Caging Single Avocado Trees with a Beehive Does Not Guarantee Exclusive Formation of Selfed Progeny
Authors: Degani C. , Lahav E. , El-Batsri R. , Gazit S.
Published: February 2019

Single trees of several avocado (Persea americana Mill.) cultivars were caged with a beehive for the production of selfed progeny. Isozyme analysis was used to identify undesirable outcrosses in the planted progenies. Outcrossing rates were found to be highly variable, ranging from 0 to 0.86. Short accidental breaches in the net's integrity were suspected to be the main cause for the haphazard appearance of hybrids. Indeed, when `Tova', which consistently had progenies with a high rate of hybrids (averaging 0.58) was caged very meticulously, outcrossing rate was consistently low, averaging only 0.07. Apparently, short periods of accidental exposure to open pollination can result in a high percentage of outcrossed progeny, due to the higher survival rate of outcrossed fruitlets compared to selfed ones. The residual low outcrossing rate found with meticulous caging probably occurred through the penetration of floating foreign pollen from adjacent trees. Thus, the production of pure selfed progeny in avocado requires meticulous caging and the absence of foreign cultivars around the caged trees. In general, the fact that net caging was not fully effective in excluding foreign pollen should encourage the performance of parentage analysis to confirm the purity of progenies produced in net cages.
Winter Survival of St. Augustinegrass Cultivars
Authors: Busey Philip
Published: February 2019

St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] has low freezing tolerance and suffers winter injury in the southeastern United States. Laboratory methods have determined that the lethal cold temperature of St. Augustinegrass stolons and buds is between -4.5 °C and -7.7 °C. The field survival of St. Augustinegrass to winter freezing is poorly known because most field reports have been based on a single location experiencing a single winter minimum air temperature. The objective of the study was to assess the winter survival of St. Augustinegrass cultivars across a range of winter minimum air temperatures occurring in experimental plantings at 24 Florida counties, following a severe Arctic cold front that moved through Florida beginning 21 Dec. 1989. Except for two counties, the limit for St. Augustinegrass winter survival was a minimum air temperature between -6 °C and -9 °C. Based on a nonlinear estimate using a 3-parameter sigmoidal model (r2 = 0.70, P < 0.0001), 50% survival of St. Augustinegrass would be predicted at -7.9 °C. Time since planting had no relationship with survival. Differences among St. Augustinegrass cultivars were observed at only two counties.
Prohexadione-calcium Suppression of Apple Tree Shoot Growth as Affected by Spray Additives
Authors: Byers R.E. , Carbaugh D.H. , Combs L.D.
Published: February 2019

Technical grade prohexadione-calcium (93.2% a.i. P-Ca) applied to `Fuji'/M.9 trees in three applications in deionized water reduced shoot growth by 25%, but the addition of (NH4)2SO4 to P-Ca suppressed shoot growth by 47%. If P-Ca was mixed in well water (high in calcium salts), P-Ca did not suppress shoot growth at all. The commercially formulated prohexadione-calcium [Apogee: 27.5% P-Ca + 56.1% (NH4)2SO4 + 16.4% other proprietary additives] + Regulaid in well water (high calcium) was not as effective (reduced growth by 30%) as when additional (NH4)2SO4 was added (reduced growth by 53%), and if CaCl2 (used to control corking) was tank mixed with Apogee + Regulaid, the Ca++ interfered with the growth suppression of P-Ca. If (NH4)2SO4 was added at the same rate as CaCl2 (w/w), the Apogee growth suppression was completely restored (reduced growth by 50%). Choice (a commercial water conditioner that has (NH4)2SO4 in the formulation, among other ingredients) + Li-700, or (NH4)2SO4 + Silwet L-77, or (NH4)2SO4 + Silwet L-77 + Oil were among the most effective adjuvant combinations with Apogee. The addition of ethephon at 270 mg·L-1 improved the growth suppression of Apogee + (NH4)2SO4 + Regulaid. Solubor compromised the effectiveness of Apogee + Regulaid. Adjusting the pH of the Apogee + (NH4)2SO4+ Regulaid spray to either pH = 4 or pH = 9 did not affect efficacy. The combination of Apogee + (NH4)2SO4 + Regulaid caused increased fruit cracking of `Empire' fruit as compared to the control (7%), presumably due to increased absorption of P-Ca. Chemical names used: Prohexadione-calcium (P-Ca, 3-oxido-4-propionyl-5-oxo-3cyclohexenecarboxylate) formulated as BAS-125 (10% P-Ca); Apogee (27.5% P-Ca), or Technical 93.5% P-Ca); Regulaid (polyoxyethylenepolypropoxy-propanol, alkyl 2-ethoxethanol, and dihydroxy propane); Silwet L-77 (polyalkyleneoxide modified heptametyltrisiloxane, silicon surfactant), LI-700 (80%, phosphatidylcholine, methylacetic acid and alkyl polyoxyethylene ether); Superior Oil (Drexel Damoil 70-second delayed dormant spray oil); ethephon (2-chloroethyl phosphonic acid); Solubor (20.5%, Boron equivalent); captan (N-Trichloromethylthio-4-cyclohenene-1,2-dicarboximide).
Host Status of Lisianthus `Mariachi Lime Green' for Three Species of Root-knot Nematodes
Authors: Schochow Martin , Tjosvold Steven A. , Ploeg Antoon T.
Published: February 2019

Lisianthus [Eustoma grandiflorum (Raf.) Shinn.] plants were grown in soil infested with increasing densities of Meloidogyne hapla Chitwood, M. incognita (Kofoid & White) Chitwood, or M. javanica (Treub) Chitwood, root-knot nematodes. Compared to tomato plants grown in soil with the same nematode numbers and species, lisianthus had less severe root symptoms, suffered less damage, and resulted in lower nematode multiplication rates. Lisianthus was a better host for M. javanica than for M. incognita, and a poor host for M. hapla. Lisianthus shoot weights were significantly reduced after inoculation with M. javanica or M. hapla, but not after M. incognita inoculation. The number of flowers produced per lisianthus plant was reduced by all three nematode species. The results show that the root-knot nematode species that are most common in California may cause significant damage in the cut-flower production of lisianthus.
Capsaicin Content of West Indies Hot Pepper Cultivars Using Colorimetric and Chromatographic Techniques
Authors: Gibbs Harold A.A. , O'Garro Leonard W.
Published: February 2019

Colorimetric and chromatographic methods were used to assess capsaicinoid levels in a pungent Caribbean-grown pepper collection comprising 28 accessions of Capsicum chinense and one each of C. annuum and C. frutescens. Two colorimetric methods, one commonly used and attributed to Bajaj (1980) and a modification of the Bajaj method were also compared for congruity and ease of use. Capsaicin content of the cultivars ranged from 37.6 to 497.0 mg/100 g in ripe fruits and 27.8 to 404.5 mg/100 g in green fruit, as determined by Bajaj's method. The corresponding Scoville units of pungency varied from 15,000 to 300,000 for ripe fruit and 7,500 to 270,000 for green fruit. Levels of capsaicin assessed by the modified Bajaj method varied from 15.0 to 402.4 mg/100 g and 13.7 to 356.4 mg/100 g in ripe and green fruit, respectively. On the basis of capsaicin levels assessed by each colorimetric method, the pepper cultivars were differentiated into seven distinct pungency groups. For each method, similar groupings of cultivars were observed for ripe and green fruit and groups of the same numerical designation were mainly comprised of common assessions. These results indicate that the two colorimetric methods generally agree. In contrast, the modified colorimetric method was more efficient than Bajaj's procedure, which required pretreatment of pepper extracts to remove the extracting solvent by evaporation and interfering chromogenic pigments by column chromatography. Phase separation of capsaicin and interfering pigments in pepper extracts by use of dilute acid was the only pretreatment required in the modified Bajaj method before colorimetry. High performance liquid chromatography performed on fruit extracts of the cultivars revealed the presence of the capsaicinoids capsaicin, homocapsaicin, dihydrocapsaicin, nordihydrocapsaicin, and homodihydrocapsaicin. Capsaicin and homocapsaicin were detected in greater abundance than dihydrocapsaicin and nordihydrocapsaicin in fruit of all cultivars. Homodihydrocapsaicin was the least abundant of the capsaicinoids and was generally absent in ripe fruit.
Effect of Low Levels of Ethylene on Sprouting of Potatoes in Storage
Authors: Wills R.B.H. , Warton M.A. , Kim J.K.
Published: February 2019

Potato tubers (Solanum tuberosum cv. Sebago) were stored at 20 °C in air containing ethylene at <0.005, 0.01, 0.1, 1.0, or 10 μL·L-1 and the level of sprouting was measured over 35 days. The time for tubers to develop an average of one sprout per tuber was found to linearly increase as the log10 ethylene concentration decreased with the effect present over the whole range of concentration. After 35 days of storage, the number of sprouts/tuber was inversely related to the ethylene concentration, but the weight of sprouts was only lower for tubers held in <0.005 μL·L-1 ethylene. The more numerous sprouts on tubers held in 10 μL·L-1 ethylene were short and thick, while the less numerous sprouts on tubers in 0.01-1.0 μL·L-1 were long, thin, and branched, and resulted in no significant difference in total sprout weight between these concentrations. Reducing the concentration of ethylene in the atmosphere around stored potatoes thus reduced sprouting, but levels <0.01 μL·L-1 are required to minimize both sprout emergence and sprout growth.
Morphology, Turf Quality, and Heat Tolerance of Intermediate Ryegrass
Authors: Richardson M.D.
Published: February 2019

Bermudagrass (Cynodon spp.) turf is often overseeded with a cool-season species such as perennial ryegrass (Lolium perenne L.) to provide an improved winter surface for activities such as golf or athletic events. Perennial ryegrass can become a persistent weed in overseeded turf due to the heat and disease tolerance of improved cultivars. Intermediate ryegrass is a relatively new turfgrass that is a hybrid between perennial and annual ryegrass (L. multiflorum Lam.). Very little information is available on intermediate ryegrass as an overseeding turf. Greenhouse, field, and growth chamber studies were designed to compare two cultivars of intermediate ryegrass (`Transist' and `Froghair') with three cultivars of perennial ryegrass (`Jiffie', `Racer', and `Calypso II') and two cultivars of annual ryegrass (`Gulf' and `TAM-90'). In a greenhouse study, the perennial ryegrass cultivars had finer leaf texture (2.9-3.2 mm), shorter collar height (24.7-57.0 mm), and lower weight/tiller (29-39 mg) than the intermediate and annual cultivars. In the field studies, the intermediate cultivar Transist exhibited improved turfgrass quality (6.1-7.1) over the annual cultivars (4.5-5.8) and the other intermediate cultivar Froghair (5.4-5.7). However, neither of the intermediate cultivars had quality equal to the perennial ryegrass cultivars (7.0-7.9). The perennial ryegrass cultivars exhibited slow transition back to the bermudagrass compared to the annual and intermediate ryegrass cultivars. In the growth chamber study, the annual and intermediate cultivars all showed increased high-temperature stress under increasing temperatures compared to the perennial cultivars, which did not show stress until air temperature exceeded 40 °C. Collectively, these studies indicate that the intermediate ryegrass cultivar Transist may have promise as an overseeding turfgrass due to its improved quality compared to annual types and a lack of heat tolerance relative to perennial cultivars, but with transition qualities similar to perennial ryegrass.
Juice Quality of `Valencia' Sweet Oranges Borne on Different Inflorescence Types
Authors: Barry Graham H. , Castle William S. , Davies Frederick S.
Published: February 2019

The objectives of this study were to determine whether juice quality of `Valencia' sweet orange [C. sinensis (L.) Osb.] is affected by the type of inflorescence on which fruit are borne, and to determine the contribution of inflorescence type to within-tree variation in juice quality. During the 1998-99 and 1999-2000 seasons, fruit size and juice quality [soluble solids concentration (SSC) and titratable acidity (TA)] of fruit from `Valencia' sweet orange trees on Carrizo citrange rootstock [Poncirus trifoliata (L.) Raf. × C. sinensis (L.) Osb.] planted in 1987 at Howey-in-the-Hills, Fla., were measured. A 2×2 factorial design (inflorescence type × canopy position) with leafy and leafless inflorescence types, and southwest top and northeast bottom canopy positions was used. The type of inflorescence on which fruit were borne had a minor effect on juice quality, and inflorescence type and juice quality were not directly associated. Rather, juice SSC was associated with the effect of inflorescence type on fruit size, as small fruit tended to have higher SSC than large fruit, regardless of the type of inflorescence on which fruit were borne. The relatively small difference in SSC between fruit borne on leafy and leafless inflorescences (≈3% of mean SSC) was an indirect result of fruit size. Therefore, fruit borne on leafy inflorescences, which tend to be of larger size compared with fruit borne on leafless inflorescences, tended to have marginally lower SSC. Acid content and ratio of SSC: TA were not related to inflorescence type. In addition, the type of inflorescence on which fruit were borne made only a nominal contribution to variability in juice SSC, in contrast to the major contribution of canopy position to within-tree variation in juice SSC. Factors other than inflorescence type are important components of within-tree variation in juice SSC.
Shading Affects Morphology, Dry-matter Partitioning, and Photosynthetic Response of Greenhouse-grown `Chardonnay' Grapevines
Authors: Heuvel Justine E. Vanden , Proctor John T.A. , Fisher K. Helen , Sullivan J. Alan
Published: February 2019

In order to gain an understanding of the capacity of severely shaded leaves to be productive in dense canopies, the effects of increased shading on morphology, dry-matter partitioning, and whole-plant net carbon exchange rate (NCER) were investigated on greenhouse-grown Vitis vinifera L. `Chardonnay' grapevines. Vines were subjected to whole-plant shading levels of 0%, 54%, 90%, and 99% of direct sun 3 weeks after potting. Data were collected 8 to 10 weeks after potting. Nonlinear regression was used to investigate the relationship of leaf morphological traits and organ dry weights to increased shading. Leaf size was maintained with increased shading to approximately the 90% shading level, while leaf fresh weight, volume, density, and thickness were immediately reduced with increased shading. Root dry weight was most affected by increased shading, and root to shoot ratio was reduced. When nonlinear regressions were produced for light response curves, light compensation point was reduced by approximately 49% by moderate shading, and 61% by severe shading. Shaded leaves approached the asymptote of the light response curve more quickly, and had reduced dark respiration rates, indicating that the morphological compensation responses by the vine allow shaded leaves to use available light more efficiently. However, the long-term ramifications of reduced root growth in the current year on vines with shaded leaves may be significant.