bluuebunny/crossref_metadata_2025 huggingface dataset:
High Application Rates of Reclaimed Water Benefit Citrus Tree Growth and Fruit Production
Authors: Parsons Lawrence R. , Wheaton T. Adair , Castle William S.
Published: February 2019

Conversion of wastewater to reclaimed water for crop irrigation conserves water and is an effective way to handle a growing urban problem: the disposal of wastewater. Water Conserv II is a large reclaimed water project developed by Orlando and Orange County, Fla., that presently irrigates ≈1900 ha of citrus. The project includes a research component to evaluate the response of citrus to irrigation using reclaimed water. Citrus trees in an experimental planting responded well to very high application rates of reclaimed water. Irrigation treatments included annual applications of 400 mm of well water, and 400, 1250, and 2500 mm of reclaimed water. The 2500-mm rate is excessive, and since disposal was of interest, this rate was used to determine if citrus could tolerate such high rates of irrigation. The effects of these treatments were compared on `Hamlin' orange [Citrus sinensis (L.) Osb.] and `Orlando' tangelo (C. paradisi Macf. × C. reticulata Blanco) combined with four rootstocks: Carrizo citrange [Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.], Cleopatra mandarin (C. reticulata Blanco), sour orange (C. aurantium L.), and Swingle citrumelo (C. paradisi × P. trifoliata). Growth and fruit production were greatest at the highest irrigation rate. Concentration of soluble solids in the juice was usually lowered by the highest irrigation rate, but total soluble solids per hectare were 15.5% higher compared to the 400-mm rate, due to the greater fruit production. While fruit soluble solids were usually lowered by higher irrigation, the reduction in fruit soluble solids observed on three of the rootstocks did not occur in trees on Carrizo citrange. Fruit peel color score was lower but juice color score was higher at the highest irrigation rate. Crop efficiency (fruit production per unit of canopy volume) was usually lower at the 2500-mm rate and declined as trees grew older. Weed cover increased with increasing irrigation rate, but was controllable. Irrigation with high rates of reclaimed water provided a satisfactory disposal method for treated effluent, benefited growth and production of citrus, and eliminated the need for other sources of irrigation water. Reclaimed water, once believed to be a disposal problem in Florida, is now considered to be one way to meet irrigation demands.
Enhancement of In Vitro Conidia Production in Monilinia vaccinii-corymbosi (Reade) Honey by Cellulose Acetate Membranes
Authors: Stretch A.W. , Ehlenfeldt M.K. , Brewster V.
Published: February 2019

In vitro conidia production by Monilinia vaccinii-corymbosi (Reade) Honey, the cause of mummy berry disease in blueberry, was significantly enhanced by cellulose acetate membranes placed on the surface of V-8 juice agar for most of the pathogen isolates tested, compared to V-8 juice agar alone. Temperature and light affected conidia production, but the effects were not consistent. Higher temperature (22 vs. 15 °C) yielded better sporulation, but the effects of light environment were variable. When 55 isolates from various sources were rated visually for sporulation on cellulose acetate membranes at 22 °C under ambient light/dark cycles, a wide range of conidium production was observed, and three of 55 isolates (6%) were identified as having very high conidia production.
NAA and 3,5,6-TPA Control Mature Fruit Drop in California Citrus
Authors: Anthony Michael F. , Coggins Charles W.
Published: February 2019

The synthetic auxins NAA and 3,5,6-TPA were investigated for reducing abscission of mature citrus fruit in California (CA). NAA was investigated on navel orange trees in San Joaquin Valley and southern CA locations. Of the seven NAA experiments presented, five had substantial fruit drop. In these five experiments, a treatment of NAA reduced drop by 31% to 88% compared to the untreated control. Although NAA treatments as low as 25 mg·L-1 (acid equivalent) reduced drop, the greatest reductions in drop were obtained by spray concentrations in the 100 to 400 mg·L-1 range. 3,5,6-TPA was investigated for fruit drop control properties on navel orange and grapefruit grown in various CA locations. The untreated control in seven of the ten 3,5,6-TPA experiments had substantial fruit drop. In each of these cases, a treatment of 10, 15 or 20 mg·L-1 (acid equivalent) of 3,5,6-TPA reduced drop 69% to 96% compared to the untreated control. A strong linear response from 3,5,6-TPA in these seven experiments indicates maximum fruit drop reduction from the highest rate investigated. On an acid equivalent basis 3,5,6-TPA seems to be comparable to 2,4-D. Both NAA and 3,5,6-TPA were effective in controlling preharvest fruit drop in citrus under CA conditions. Both materials provided fruit holding late into the harvest season. NAA, and in particular 3,5,6-TPA, offer the potential to provide a substitute for 2,4-D which is commonly used for controlling fruit drop in many countries. Chemical names used: naphthaleneacetic acid (NAA); 3,5,6-trichloro-2-pyridinyloxyacetic acid (3,5,6-TPA, triclopyr); 2,4-dichlorophenoxyacetic acid (2,4-D).
Earthworm Castings as a Substrate for Poinsettia Production
Authors: Hidalgo Pablo R. , Harkess Richard L.
Published: February 2019

Experiments were conducted to evaluate earthworm castings (vermicompost) as a substrate for poinsettia (Euphorbia pulcherrima Willd.) `Freedom Red' production. Vermicomposts produced from sheep, cattle, or horse manures were mixed at different ratios with 70 peatmoss: 30 perlite (v/v) to create 13 substrates. Chemical and physical properties were measured on all substrates used. Growth index, foliar and bract area, and dry weight were greater on plants grown in substrates with castings from sheep or cattle manure. These castings had greater initial nutrient content than the castings from horse manure. Mixtures of castings and peat produced better plant responses than castings alone. Better plant responses were sometimes associated with values outside the recommended pH and electrical conductivity levels for poinsettia production. The highest values obtained for growth index, foliar and bract area, dry weight, and root development were produced in the substrates with moderate pore space or water holding capacity. Substrates with greater air space produced plants with greater dry weight and root development than substrates with less air space. The highest quality plants were grown in substrates with 25% castings from sheep or cattle manures.
High ß-carotene and Capsaicinoid Contents in Seedless Fruits of `Shishitoh' Pepper
Authors: Ishikawa Keiko , Sasaki Shiho , Matsufuji Hiroshi , Nunomura Osamu
Published: February 2019

In order to evaluate the advantages of parthenocarpy in the breeding of Capsicum, we investigated the percentage of fruit set after emasculation or excision of styles, fruit size, and amounts of ß-carotene, capsaicinoids, and ascorbic acids of the seedless fruits of Capsicum annuum L. `Shishiroh' no. 562. Seedless fruits were induced from ≈80% of flower buds after emasculation or excision of styles. The levels of ß-carotene (44.07 μg·g-1), capsaicin (1.73 mg·g-1), and dihydrocapsaicin (1.12 mg·g-1) of mature seedless fruits were 10 times higher than those of seeded fruits. The amount of ascorbic acid, however, was at the same level (≈230 mg/100 g). The length of the seedless fruit was ≈50% smaller than that of the seeded fruit at 2 weeks after the flowering and decreased to 44% at mature stage.
Screening for Powdery Mildew Resistance in Pulmonaria
Authors: Krahl Kimberly H.
Published: February 2019

A screening technique was developed for studying resistance to powdery mildew disease in 25 diverse Pulmonaria L. species and cultivars. Healthy Pulmonaria plants were inoculated by drawing naturally infected leaves of P. angustifolia `Blaues Meer' across the abaxial surface of three healthy, mature leaves per test plant. Inoculated leaves were rated for powdery mildew infection using a scale of 0-5, where 0 = no visible sign of infection, 1 = 1% to 20%; 2 = 20% to 40%; 3 = 40% to 60%; 4 = 60% to 80%; 5 = 80% to 100% of leaf surface covered with white mycelial growth. Each genotype was inoculated and evaluated four times. The data revealed a wide and continuous range of variability for powdery mildew disease incidence in the 25 lungwort genotypes that may be indicative of quantitative resistance. The majority of lungwort genotypes exhibited low levels of resistance to powdery mildew. Four cultivars (P. hybrid `Spilled Milk', P. hybrid `Excaliber', P. rubra `Redstart', and P. rubra `David Ward') and one selection (P. longifolia ssp. cevennensis) exhibited high levels of resistance to powdery mildew. Since Pulmonaria species intercross readily, these genotypes may be useful in the future development of new powdery mildew resistant Pulmonaria cultivars.
Effective Pollination Period in Almond Cultivars
Authors: Ortega E. , Egea J. , Dicenta F.
Published: February 2019

In almond [Prunus dulcis (Mill.) D.A. Webb], a high flower density and fruit set rate is important, because yield increases with higher fruit set ratio. Furthermore, because the ovule of some cultivars mature at anthesis, rapid pollination and pollen tube growth along the style are essential to ensure fertilization of a viable ovule. In this work, we studied the effective pollination period (EPP) of four almond cultivars of different bloom time by studying pollen tube growth and fruit set. EPP in almond was longer than in other fruit trees, and its duration was determined by stigma receptivity, which decreased with high temperature. An acceptable fruit set for all cultivars was obtained following pollination from day 0 to day 4 after emasculation.
Irrigation Method and Temperature of Water Affect Height of Potted Easter Lilies
Authors: Blom Theo , Kerec David , Brown Wayne , Kristie Dave
Published: February 2019

Potted greenhouse-forced `Nellie White' Easter lilies (Lilium longiflorum Thunb.) were irrigated from emergence with water at 2, 5, 8, 11, or 15 °C either onto the shoot apex (overhead) or onto the substrate for a 0, 2-, 4-, 6-, 8-, 10-, or 12-week period. Control treatment was at 18 °C, either overhead or on substrate. When irrigation water was applied overhead for the entire period between emergence and flowering (12 weeks), plant height increased linearly with the temperature of irrigation water (1.75 cm/°C). As the period of application with cold water increased from 0 to 12 weeks, plant height decreased both in a linear and a quadratic manner. Forcing time was negatively correlated with height with the shortest plants delayed by 3 to 6 days. Water temperature did not affect bud abortion or the number of yellow leaves. Irrigation water temperature had no effect on plant parameters when applied directly on the substrate.
Efficacy of Exogenous Calcium Applications for Reducing Upper Leaf Necrosis in Lilium `Star Gazer'
Authors: Chang Yao-Chien , Grace-Martin Karen , Miller William B.
Published: February 2019

Upper leaf necrosis (ULN) on Lilium `Star Gazer' is a calcium deficiency disorder. In this study, we evaluated the efficacy of foliar Ca sprays and bulb Ca dipping on reducing ULN. Necrosis severity of a single leaf was determined by an index from 0 (healthy) to 5, based on symptom progression and necrosed leaf area. Single leaf severity was then summed for all leaves to yield a whole-plant severity rating. Single daily applications of 25 mm calcium chloride or calcium nitrate sprays for 14 days significantly suppressed the degree of symptom expression; whole-plant severity was reduced from 18 (severely necrosed) to below 3 (essentially unnoticeable). Five single applications at 3.5-day intervals were not effective, even at concentrations up to 150 mm. At concentrations of 100 and 150 mm, 14 daily sprays of calcium chloride or calcium nitrate were toxic and caused leaf tip yellowing; calcium chloride caused more severe phytotoxicity than did calcium nitrate. For effectiveness of foliar Ca sprays, it was necessary to have the Ca solution reach the enclosed, young, expanding leaves. Preplant bulb immersion in calcium chloride was not effective even at concentrations as high as 400 mm for up to 16 hours.
Multispectral Radiometer Signatures for Stress Evaluation in Compacted Bermudagrass Turf
Authors: Guertal E.A. , Shaw J.N.
Published: February 2019

A 3-year study was conducted in Auburn, Ala., on an established hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy `Tifway'] stand maintained at a 2.54-cm mowing height. Treatments were level of soil traffic applied via a weighted golf cart to produce turf and soil that received varying amounts of traffic. Dormant bermudagrass was overseeded with perennial ryegrass (Lolium perenne L.) each October, which remained until May of each year. Spectral data were collected monthly using a multispectral radiometer. Percent reflectance data were acquired over 512 discrete wavelengths in visible (VIS) and near-infrared (NIR) ranges. Quarterly data collection included soil penetrometer and bulk density measurements to a depth of 15 cm. After 2 years of traffic, both soil penetrometer and bulk density data indicated statistically significant increases in soil compaction. In general, as traffic increased there were also increases in percent reflectance in the VIS range. Data were subject to temporal variation, however, as values changed with the date of sample collection. The NIR reflectance data provided little consistent correlation to measurements of soil compaction. Use of NIR and VIS radiometry to evaluate turf stress showed some potential, but temporal variation must be considered.
Coal Combustion By-product (CCB) Utilization in Turfgrass Sod Production
Authors: Schlossberg Maxim J. , Miller William P.
Published: February 2019

Coal combustion by-products (CCB) are produced nationwide, generating 108 Mg of waste annually. Though varied, the majority of CCB are crystalline alumino-silicate minerals. Both disposal costs of CCB and interest in alternative horticultural/agricultural production systems have increased recently. Field studies assessed the benefit of CCB and organic waste/product mixtures as supplemental soil/growth media for production of hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy] sod. Growth media were applied at depths of 2 to 4 cm (200 to 400 m3·ha-1) and vegetatively established by sprigging. Cultural practices typical of commercial methods were employed over 99- or 114-day growth periods. Sod was monitored during these propagation cycles, then harvested, evaluated, and installed offsite in a typical lawn-establishment method. Results showed mixtures of CCB and biosolids as growth media increased yield of biomass, with both media and tissue having greater nutrient content than the control media. Volumetric water content of CCB-containing media significantly exceeded that of control media and soil included with a purchased bermudagrass sod. Once installed, sod grown on CCB-media did not differ in rooting strength from control or purchased sod. When applied as described, physicochemical characteristics of CCB-media are favorable and pose little environmental risk to soil or water resources.
Airblast Application of Copper Fungicide to Grapefruit Does Not Affect Windscar
Authors: Stover Ed , Hebb Jack , Sonoda Ron , Salyani Masoud
Published: February 2019

Wind-induced blemishing known as windscar and lesions from the disease melanose (caused by Diaporthe citri) are two of the most important causes of fresh grapefruit (Citrus paradisi) cullage in Florida. Copper hydroxide fungicides are the primary means of controlling melanose, but high air velocities from passing sprayers have been suspected of increasing windscar. In 1998 and 1999, airblast applications of Cu(OH)2 (1.7 kg·ha-1 Cu) were made at a range of early fruit development stages to a fresh grapefruit orchard in the Indian River region of Florida. These applications supplemented aerial sprays of Cu(OH)2 that were made uniformly across the entire experimental site at biweekly intervals beginning near full bloom. During the commercial harvest period fruit were sampled from three regions (interior, upper exterior, and lower exterior) of each treatment tree and were evaluated for percentage of fruit surface covered by windscar and severity of melanose. Airblast applications did not affect windscar in either year, but windscar was significantly greater from the upper exterior of the canopy, which is likely to experience the highest natural wind velocities. From these data, it appears unlikely that airblast applications significantly contribute to windscar of Indian River grapefruit. In 1998, no trees receiving airblast applications had significantly lower melanose incidence than the trees sprayed only via aircraft; however, trees receiving four airblast applications were scored as having higher apparent melanose on exterior samples than trees receiving most other treatments. This is consistent with high levels of Cu injury on these fruit which can superficially resemble melanose. Following treatment in 1999, trees receiving four airblast applications of Cu(OH)2 had significantly lower melanose scores than trees receiving either no or only early airblast applications, but were not significantly different from trees receiving a single spray 5.5 weeks postbloom. A computer model, which estimates Cu levels on fruit based on fruit growth, rainfall, and application parameters, indicated exterior fruit receiving four airblast sprays had >3 μg·cm-2 [Cu] for 40 days in 1998 but only 10 days in 1999, which reflects increased probability of Cu damage in 1998. It appears that aerial application supplemented by airblast merits further study as an economical means of melanose control.
Control of Citrus Nematode with Ditera WDG, a Biological Nematicide, Applied through Minisprinkler Irrigation
Authors: Ray* Daniel E. , McNeil Robert J.
Published: February 2019

The objectives of the study were to measure the effectiveness of Ditera WDG, a biological nematicide derived from the fermentation of a nematode-parasitic isolate of the Myrothecium species, in controlling citrus nematode numbers and the effects on tree growth, fruit yield, and fruit size as applied through minisprinkler irrigation. Nematode-infested trees utilized for the study included three different blocks of sweet oranges: 1) 20-year-old `Valencia' orange trees on Troyer citrange rootstock; 2) 15-year-old Washington navel orange trees on Troyer citrange rootstock; and 3) 8-year-old Washington navel orange trees on three citrange rootstocks (Troyer, Carizzo, and C-35). Three treatments were utilized within each orchard block: 1) 28.01 kg of active ingredient per hectare (25 lb per acre); 2) 56.02 kg of active ingredient per hectare (50 lb per acre); and 3) an untreated control. Treatments 1 and 2 were split into early spring and early fall applications for three seasons. Chemical was injected through minisprinkler irrigation in a 3.41 m (11.2 ft.) diameter under each tree. There was a positive trend toward reduction of nematode numbers for the high rate of Ditera in all three treatment blocks and for the low rate in one block. Effects on tree growth, fruit yield, and fruit size will also be presented.
Factors Affecting Transient Gene Expression in Mango Tissue Using Particle Bombardment
Authors: Agrez* Vaughan , Singh Zora , Gill Mis
Published: February 2019

Particle bombardment seems to be a promising method for genetic transformation of mango and the information on various factors affecting transient gene expression is inconclusive. Pro-embryonic masses (PEMs) of mango (Mangifera indica L. cv. Kensington Pride) used for particle bombardment were established and maintained in vitro using various liquid and semisolid media containing 2,4-D. Various factors affecting the biolistic transformation efficiency in mango and subsequent transient gene expression were optimized using β-glucuronidase (GUS) as a reporter gene driven by CaMV 35S promoter. Our results show that bombardment pressure significantly affects transient gene expression with the best results obtained from PEMs bombarded at 1200 kPa of helium pressure under vacuum. The application of osmoticum pre and post-bombardment also significantly increased the transient gene expression in the PEMs as compared to the controls. Mannitol (0.2 m) proved to be the best osmoticum in improving transient GUS expression as compared to sorbitol. The duration of exposure of PEMs to mannitol (0.2 m) both pre and post-bombardment also played a significant role in improving transient gene expression. The transient GUS expression was significantly highest with a pre-treatment of 0.2 m mannitol for 4 hours as compared to 0, 8 and 12 hours. The post-bombardment treatment of 0.2 m mannitol for 16 hours resulted in significantly highest transient gene expression as compared to 0, 4, 8, 12, 20 and 24 hours. In conclusion, PEMs of `Kensington Pride' mango bombarded at 1200 kPa, which were exposed to mannitol (0.2 m) for 4 and 16 hours pre and post bombardment respectively, resulted in the highest transient GUS expression (25.1 GUS foci/mg PEMs).
Evaluation of 48 Rose Cultivars for Low Maintenance Landscapes in Oklahoma
Authors: Anella* Louis B. , Reed Keith , Erickson P.I. , Cole Janet C.
Published: February 2019

Although roses have long been an important landscape plant, there is a growing interest in the use of low-maintenance roses that do not require heavy pruning or spraying. Poulsen Roser Pacific, Inc. of Central Point, Oregon, provided three plants of 48 cultivars for a trial in Stillwater, Oklahoma. The plants were produced in Oregon by grafting cultivars on seedling Rosa multiflora rootstock. Two-year-old plants were shipped bare-root to Stillwater, Oklahoma where they were planted in the field in early April, 2001. The plants were placed in three randomized complete blocks (rows) with 90 cm spacing between plants and 240 cm spacing between rows. The plants were drip irrigated as needed. During the 2002 growing season the roses were evaluated weekly for flower number, black spot, and overall quality. Four rose cultivars from Poulsen's Town and Country® series of landscape roses, Martha's Vineyard™ (`Poulans'), followed by Madison™ (`Poulrijk'), Kent™ (`Poulcov'), and Tumbling Waters™ (`Poultumb'), had the highest average flower number. Martha's Vineyard™, Kent™, and Tumbling Waters™ also rated highest among the cultivars tested for overall plant quality and black spot resistance. Other roses in the top grouping (Waller-Duncan K-ratio t test) for black spot resistance and overall quality were: Ragtime™ (`Poultieme', a climber from the Courtyard® series), Sophia Renaissance® (`Poulen002', Renaissance® series), Nashville™ (`Poulbico', Town and Country® series), Redwood™ (`Poultry', National Parks® series), Julia Renaissance® (`Poulheart', Renaissance® series), Santa Barbara™ (`Pouloesy', Town and Country® series), and Everglades™ (`Poulege', National Parks® series).
Effect of Shade on Quality of Greenhouse Tomato
Authors: Gent* Martin P.N.
Published: February 2019

Shading a greenhouse increased the fraction of tomatoes that were marketable, and the marketable yield, in a comparison of greenhouse tomato yields across years, in some of which the greenhouses were shaded. In 2003, the yield and quality of greenhouse tomatoes were compared directly when grown in spring and summer in Connecticut in identical greenhouses that differed only in the degree of shade. Each half of four greenhouses was either unshaded or shaded using reflective aluminized shade cloth rated to reduced light transmission by 15%, 30%, or 50%. Each shade treatment was repeated in two houses. Tomatoes were germinated in February and transplanted in March The houses were shaded when fruit began to ripen in early June. Picking continued through August. The effect of shade on total yield developed gradually. Yields in June were unaffected by shade, but in August yield under no shade was about 30% higher than under 50% shade. In contrast, there was an immediate effect of shade on fruit size. Fruit picked in June from plants under 50% shade was 16% smaller than from plants grown under no shade. This difference declined later in the season, to 6 and 9%, in July and August respectively. The highest yield of marketable fruit in 2003 was picked from houses under no shade, but this was only 10% more than picked from the houses under 50% shade. Shade increased the fraction of marketable fruit, from 54% under no shade to 63% under 50% shade. Certain defects were decreased by shade. For instance the fraction of fruit with cracked skin was decreased from 33% to 25%. In general, effects on fruit quality varied linearly with the degree of applied shade.
Examining the Vascular Transport System in Grafted Prunus avium L. on Dwarfing Rootstocks
Authors: Olmstead Mercy A. , Lang* N. Suzanne , Ewers Frank W. , Owens Shirley A.
Published: February 2019

Dwarfing rootstocks in sweet cherry (Prunus avium L.) have been planted worldwide. No single theory has emerged to answer why scion dwarfing occurs in fruit trees. This research examines the vascular pathway in a dwarfing cherry system to determine if physical limitations alter water transport as a possible dwarfing mechanism. Second-leaf `Lapins' trees grafted onto Gisela 5 (Gi5; dwarfing) and Colt (vigorous) rootstocks were field-grown in East Lansing, Mich. During maximum shoot elongation, trees were dug, placed into containers with safranin dye solution (0.1% w/v) for 6 hours and then removed for division (3-5 cm in length) based on location in scion, graft union, and rootstock tissue. Tissues were sectioned using a sliding microtome (120 μm) for examination with a laser confocal microscope (Zeiss LSM Pascal). Mean stem area and vessel diameter were measured; and mean hydraulic diameter was calculated for vessels in the area of dye translocation. Overall, Lapins/Gi5 stem area in the graft union was larger compared to Lapins/Colt; however dye translocation in Lapins/Gi5 was reduced compared to other tissues in the tree. Confocal microscopy indicated dye uptake through the grafted region was more uniformly distributed in Lapins/Colt than in Lapins/Gi5, with dye accumulation in areas of maximum translocation. Vessel diameter did not differ in these areas of translocation. However, in both combinations there was a reduction in mean hydraulic diameter of graft union sections, suggesting a reduction in vessel efficiency to translocate water in this region. Vascular system anomalies were more frequent in Lapins/Gi5, disrupting acropetal dye translocation. This suggests the greatest reduction in vascular transport is in Lapins/Gi5.
Water Use and Stomatal Behavior of Sweetgum (Liquidambar styraciflua) Relative to Reference Evapotranspiration in Three Contrasting Regions
Authors: Kjelgren* Roger , Montague Thayne , Beeson Richard
Published: February 2019

We investigated water use and a water needs index multiplier relative to reference evapotranspiration for a sweetgum cultivar (Liquidambar styraciflua `Moraine') in Logan, Utah, Lubbock, Texas, and Orlando Fla. Three individual trees with ≈80-mm trunk diameter, were potted in to large containers with organic media at each location. Sweetgum water use (Tsw) was measured over the season at each location with load cells and dataloggers, concurrent with measurement of reference evapotranspiration (ETo) from adjacent weather stations. Dawn-to-dusk stomatal conductance (Gs) was measured several times during the season at all locations. Trees were watered daily. At the end of the season, total tree leaf area was collected and used to normalize volumetric water use data to depth units. Tsw was highest in Florida, up to 4 mm/day, as was maximum daily Gs. Tsw only reached 2.5 mm/day in Texas and Utah due in part to stomatal sensitivity to high vapor pressure deficits that moderated transpiration. There was no relationship between Tsw and ETo at ETo levels above 4 mm/day in Texas and Utah, resulting in substantial scatter in the water needs index multiplier relative to ETo that centered on 0.3 in Texas and 0.4 in Utah. Tsw in Florida showed an upper boundary relationship with ETo, under which it varied considerably, resulting in a values relative to ETo centered on 0.6. During a partial dry down in Utah, morning Gs was unaffected while afternoon Gs declined progressively under mild water stress, resulting multiplier values of 0.15-2. The study shows that regional climate affects tree water use independent of effects measured in ETo, increasing the uncertainty of sweetgum water use estimated as a function of ETo.
Glomus intraradices Enhances Growth and Gas Exchange of Lolium perenne Seedlings in Petroleum-contaminated Soil
Authors: Alarcon* Alejandro , Davies Frederick T. , Reed David Wm. , Autenrieth Robin L. , Zuberer David A.
Published: February 2019

Arbuscular mycorhizal fungi (AMF) have been used in phytoremediation and can increase tolerance and growth of plants in contaminated environments. However, little is known about the influence AMF on plant growth to organic contaminants in soils. A greenhouse experiment was conducted to study the response of seedlings of annual ryegrass (Lolium perenne L.) var. Passerel Plus inoculated with Glomus intraradices Schenck & Smith in soil contaminated with sweet Arabian median crude oil. Inoculated (AMF) and non-inoculated (Non-AMF) plants were established in an pasteurized and artificially contaminated sandy loam soil with 0; 3000; 15,000; or 45,000 mg of petroleum kg-1 soil (n = 20). Plants were inoculated with 500 spores of G. intraradices (Mycorise® ASP, PremierTech Biotechnologies, Canada). After 90 days, plant growth of AMF or Non-AMF plants, was drastically affected at all petroleum concentrations. However, G. intraradices enhanced plant growth, chlorophyll content, and gas exchange of plants grown at 3,000 mg kg-1 compared to Non-AMF plants. Total leaf area, chlorophyll, and net photosynthesis were also higher (+380%, +63%, and +81%, respectively) at this concentration. Water use efficiency (net photosynthesis/stomatal conductance) of AMF-plants was three times greater than Non-AMF at 3,000 mg·kg-1. At concentrations of 15,000 and 45,000 mg kg-1 AMF did not have effect, but colonization was observed (11.8% and 18.6%, respectively). These values of colonization were significantly lower than those observed in AMF-plants at 0 (42.5%) and 3,000 mg·kg-1 (55.6%). Studies are currently being conducted to understand the physiological role of AMF on plants exposed to organic contaminants.
Growth and Gas Exchange Responses of Olive Tree Cuttings to Elevated CO2 Concentration under Saline Conditions
Authors: Melgar J.C. , Dunlop J. , Syvertsen* J.P. , García-Sánchez F.
Published: February 2019

Physiological responses of olive cuttings of `Koroneiki' and `Picual' (Olea europaea L.) to zero or high salinity (NaCl 100 mmol·L-1) and to ambient CO2 (380 ppm) or elevated (700 ppm) CO2 concentration were studied in sand culture in greenhouses. Growth parameters, net gas exchange of leaves and leaf chloride concentration were measured after two months of treatment. `Koroneiki' had significantly greater shoot growth and net assimilation of CO2 (Ac) at elevated CO2 than at ambient CO2 but this difference disappeared under salt stress. Growth and Ac of `Picual' did not respond to elevated CO2 regardless of salinity treatment. Stomatal conductance and leaf transpiration were lower at elevated CO2 such that leaf water use efficiency increased at elevated CO2 in both cultivars regardless of saline treatment. The saline treatment increased leaf chloride (Cl) concentration and reduced growth and net gas exchange responses in both cultivars. There was no difference in leaf Cl accumulation between the two varieties. At high salinity, elevated CO2 had little effect on leaf Cl implying that at least in `Koroneiki', Cl accumulation was not closely linked to water uptake.
Utility of BoCAL-a and BoAP1-a Genotypes in Identifying Broccoli and Cauliflower Accessions
Authors: Labate Joanne A. , Robertson Larry D. , Bjorkman* Thomas
Published: February 2019

Broccoli and cauliflower are different botanical varieties of Brassica oleracea. Mutant alleles at the loci BoCAL and BoAP1 can cause arrest at curding that is characteristic of cauliflower. These genes control early floral differentiation, necessary for the progression from a cauliflower-like inflorescence to the flower buds of broccoli. To what extent is the cauliflower-to-broccoli variation within the USDA-PGRU collection determined by mutant alleles of these genes? We surveyed the broccoli collection to examine the correlation between genotype and phenotype. Earlier work showed that BoCAL alone was not an effective predictor of cauliflower phenotype in this collection. The redundant function of BoCAL and BoAP1 in determining inflorescence arrest raises the possibilty that the combined genotype can explain the phenotypic variation. We found that not to be the case. Two accessions varied in phenotype and segregated at both loci, but the combined genotypes were not associated with the expected phenotypes. Two additional accesssion varied in phenotype and segregated at one locus, but with no association between genotype and phenotype. One line varying widely in phenotype was fixed for both loci. One line that was a stable intermediate phenotype segregated for BoCAL. A commercial broccoli cultivar had the cauliflower allele at both loci. The genetic basis of the cauliflower phenotype in the USDA B. oleracea collection is due more to alleles of genes affecting the expression of BoAP1 adn BoCAL than to variation in these alleles of the genes themselves.
Inheritance and Characteristics of a New Dwarf and Seedless Mutant in Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai]
Authors: Huh Yun-Chan , Cheong Seung-Ryong , Lee* Jung-Myung
Published: February 2019

Common watermelons have an indeterminate growth habit with normal internode length, thus allowing the vine to grow indefinitely under the normal conditions. Watermelon breeders have identified four dwarf genes (dw-1, dw-1s, dw-2, dw-3) and used these for developing dwarf watermelon cultivars. We discovered a naturally occurring new dwarf and seedless mutant (NDSM) from a landrace cv. Mudungsan that had been cultivated in the Mountain Mudung area nearby Gwangju City in Korea. The progenies of this mutant segregated in a ratio of 3 vine to 1 dwarf indicating a single recessive gene nature. Morphological characteristics of the NDSM were markedly different from those of the four known dwarf genotypes. NDSM plants grow shorter than 1 m in length with fan-shaped leaves and have fewer leaf lobes than normal plants, which could be clearly distinguished at 2 or 3 true leaf stage. Male and female flowers have just one petal and failed to open completely even at the anthesis. Even though there were some fertile pollen grains, the fruits of NDSM had no seed after fertilization. The F2 progenies, obtained from crossing `920533' (normal vine type) and NDSM, segregated in a ratio of 3 vine to 1 dwarf. All F1 plants from crosses between 2 dwarf types, `Sugar Bush' (dw-1dw-1) and `NH 9' (dw-2dw-2), and NDSM were normal, while F2 showed 9 vines, 3 dw-1 or dw-2 types, 3 NDSM types, and 1 double dwarf. The backcross generation segregated in a ratio of 1 vine to 1 dwarf. These results indicate that the genes for the NDSM and 2 dwarf types are non-allelic. We named this new dwarf genotype (NDSM) as dw-4 in addition to four dwarf genes previously identified.
Genetic Linkage Map of Garlic (Allium sativum)
Authors: Zewdie Yayeh , Havey Michael J. , Prince James P. , Jenderek* Maria M.
Published: February 2019

Garlic has been propagated exclusively by asexual means since time immemorial. The recent discovery of male fertile garlic accessions allowed studies on genetics and garlic improvement. Single nucleotide polymorphism (SNP) and random amplified polymorphic DNA (RAPD) based genetic linkage map was developed for garlic using a segregating population derived from one plant of PI 540316. Progenies segregated for male fertility and other morphological characters. Distortion of segregation was observed for most of the markers. This was expected due to the segregation of recessive deleterious alleles present in the garlic genome. The map contained 23 loci distributed on five linkage groups. It covered 319 cM with the average of 18 cM between loci. Linkage with the male fertility (Mf) locus was established with SNP marker AOB155 (26.7 cM).
Effect of Neutralizing Irrigation Water Alkalinity with Acid on Nutritional Status and Growth of Thryallis (Galphimia glauca Cav.)
Authors: Albano* Joseph P. , Wilson P. Chris , Wilson Sandra B.
Published: February 2019

Sources of irrigation water in South Florida typically contain high levels of dissolved carbonates and bicarbonates. Repeated application of high alkalinity water can cause substrate-solution pH to rise, thereby altering nutrient availability, and possibly leading to the development of nutrient disorders and a reduction in plant growth. The objectives of the current study were to determine the effects of neutralizing alkalinity of irrigation water on the nutritional status and growth of Thryallis (Galphimia glauca Cav.). Plants were grown in 11.4-L containers in a 5 peat: 4 pine bark: 1sand (v:v:v) mix. Treatments were prepared with water collected from a commercial nursery with inherent calcium carbonate levels in excess of 260 mg·L-1 and pH above 7.3. Treatments consisted of 0% (control), 40%, or 80% alkalinity neutralized with sulfuric acid. At harvest, 51 weeks after initiating treatments, foliar levels of Fe were 28% greater, Mn 55% greater, and Zn 27% greater in the 80% than 0% neutralized alkalinity treatment. Growth indices and leaf greenness averaged over the course of the study were significantly greater in the 40% than in the 0% or 80% alkalinity neutralized treatments. Over the course of the study, leachate pH averaged 7.5, 6.8, and 5.3; and electrical conductivity (EC) averaged 1.4, 1.9, and 2.2 dS·m-1 in the 0%, 40%, and 80% alkalinity neutralized treatments, respectively.
The Influence of Mulching with Straw on the Field Microclimate and Ginger Growth
Authors: Xu* Kun , Wang Xiufeng , Wang Fang
Published: February 2019

Mulching with straw increase soil water content, air relative humidity and air temperature, but decreased soil temperature. Though mulching with straw didn't change light intensity, ginger growth and yield were the same as shading. The growth and yield under shading and mulching with straw were both higher than that of naked soil.
Can Pawpaw Fruit be Cold-stored for Extended Periods?
Authors: Galli* Federica , Archbold Douglas D. , Pomper Kirk W. , Hamilton-Kemp Thomas R. , Collins Randall W.
Published: February 2019

Pawpaw [Asimina triloba (L.) Dunal] is a highly perishable climacteric fruit, softening rapidly once ripening commences which may limit its marketability. In studies to determine the optimum cold storage temperature and maximum storage life of the fruit, pawpaw fruit were stored at -2, 2, and 6 °C for 1, 2, 4, 8, and 12 weeks, and then ripened upon removal to ambient temperature. Through 4 weeks, fruit exhibited adequate firmness upon removal from cold storage, but at 8 and 12 weeks fruit held at 2 and 6 °C were very soft. Irrespective of storage temperature, at 8 weeks fruit showed a delay in a climacteric-like respiratory increase, and by 12 weeks a respiratory climacteric was not apparent. An ethylene climacteric was evident after all temperature and storage periods except those held at 6 °C for 12 weeks. Significant symptoms of cold injury were found by 8 weeks of 2 °C cold storage. In addition to a delayed respiratory climacteric, pawpaw fruit stored for 8 and 12 weeks exhibited flesh browning within 48 h of moving to ambient temperature. A change in fruit aroma volatile profile suggested injury might have been developing by 4 weeks of cold storage even though other symptoms were not evident. Immediately after harvest, methyl octanoate was the dominant volatile ester followed by methyl hexanoate. By 4 weeks of postharvest cold storage, ethyl hexanoate was the dominant ester followed by ethyl octanoate, but methyl octanoate production was still substantial. At 8 weeks, volatile ester production was generally lower with ethyl hexanoate the major volatile followed by ethyl octanoate. These symptoms indicate that pawpaw fruit can suffer cold injury during extended periods of cold storage.
Inducing Optimal Ripening Capacity of 1-MCP-treated `Bartlett' Pears after Regular Air or Controlled Atmosphere Storage
Authors: Bai* Jinhe , Chen Paul , Baldwin Elizabeth , Mattheis James
Published: February 2019

`Bartlett' pears were treated with 300 nL·L-1 1-MCP at 20°C for 24 h shortly after harvest, and were stored at -1 °C in either regular atmosphere (RA) or controlled atmosphere (CA: 1.5 kPa O2 / 0.5 kPa CO2). After 2 and 4 months of RA storage, or 4 months of CA storage, fruit were pre-conditioned at 10 °C, 15 °C or 20 °C for 5, 10, or 20 days, respectively. Pre-conditioned fruit were then held at 20 °C for 14 days to simulate marketing conditions. Flesh firmness (FF) and extractable juice (EJ) were monitored during the marketing period. The optimal stage of ripeness for `Bartlett' pears was defined to be when FF decreases to 27 N and EJ decreases to 55 mL/100 g. The proper pre-conditioning combinations of temperature and duration were 15 °C or 20 °C for 10 d or 10 °C for 20 d if the fruit had been stored in RA for 2 months, 10 °C or 15 °C for 5 d if the fruit had been in RA for 4 months, and 20 °C for 10 d or 10°C for 20 d if the fruit had been in CA for 4 months, for which combinations the fruit ripened within a week and maintained quality for 14 days at 20 °C. The treatment combinations of lower temperature and/or shorter duration times in pre-conditioning delayed the ripening response of the fruit, and combinations of higher temperature and/or longer duration times in pre-conditioning resulted in a shorter marketing life because of senescence breakdown, in comparison the optimal combinations mentioned above. These results indicate that pre-conditioning regimes for 1-MCP treated `Bartlett' pears are storage atmosphere and time dependent. Generally, CA stored fruit needed more preconditioning (in terms of higher temperature and/or longer duration) than did RA stored fruit.
The Idaho Master Gardener Program—Diverse, Different, and Meeting Local Needs
Authors: Robbins* Jo Ann , Bell Susan , Davis Tim , Laughlin Kevin
Published: February 2019

Master Gardener training was first offered in Idaho in 1976. Univ. of Idaho (U of I) Master Gardener trainings are held in various counties and organized by county extension faculty. The number of Master Gardeners in Idaho is estimated at 1800. In 1993, U of I published the first edition of the Idaho Master Gardener Handbook. This 23-chapter state-specific handbook is revised annually. The first chapter outlines the Idaho Master Gardener guidelines. These were the first statewide guidelines. The Idaho program requires a minimum of 30 hours of classes and 30 hours of practicum/hands-on training (the volunteer commitment). Certification is received after these requirements are met and is good for one year. Annual recertification is provided through participation in Advanced Master Gardener trainings and activities. These recertification programs differ; depending on wants and needs within Idaho. The U of I Horticulture Programming Topic Team loosely organizes all county efforts, but there is no statewide Master Gardener program in Idaho. Each region and county brings a unique framework to the title Master Gardener. Hands-on training in many counties includes problem solving services to phone and office visiting clients. Other horticultural community and extension projects are the balance of the hands on hours. Idaho Master Gardeners also serve as uniquely qualified educators in a state as geographically diverse as Idaho. In 2001, the Idaho Junior Master Gardener Program began in cooperation with Idaho Master Gardeners and Texas A&M Univ.. Over 2000 youth and 200 adults have been involved in Idaho.
Compatibility of Radish, Lettuce, and Bunching Onions Grown Hydroponically in a Mixed-crop System
Authors: Yorio Neil C. , Richards Jeff T. , Edney Sharon L. , Wilkinson Joel O. , Stutte* Gary W. , Wheeler Raymond M.
Published: February 2019

The effects of using mixed cropping strategies for reducing overall mass and increasing system efficiency was examined as part of NASA's mission to study minimally-processed or “salad” crops as dietary supplements on long-duration space missions. To test interspecific compatibility, radish (Raphanus sativus L. cv. Cherry Bomb II), lettuce (Lactuca sativa L. cv. Flandria), and bunching onion (Allium fistulosum L. cv. Kinka) were grown hydroponically as either monoculture (control) or mixed-crop within a walk-in growth chamber maintained at 25 °C, 50% relative humidity, 300 μmol·m-2·s-1 PPF, and a 16-h light/8-h dark photoperiod under cool-white fluorescent lamps. Weekly time-course harvests were taken over 28 days of growth. Results showed that none of the species showed any negative growth effects when grown together under mixed-crop compared to monoculture growth conditions. However, radish showed significant increases in edible mass when grown under mixed-crop compared to monoculture conditions. The observed increases in growth are likely attributable to increased light interception due to a decreased guard row effect as well as a faster canopy development for radish.
Effect of Nitrogen Rate and Residual Soil Nitrogen on Yield and Quality of Carrots
Authors: Westerveld Sean M. , McKeown Alan W. , McDonald* Mary Ruth
Published: February 2019

Residual nitrogen (N) in agricultural soils is an environmental concern. Nitrogen requirements for carrots were examined over a two-year period in Ontario, Canada. Carrots, cvs. `Idaho' and `Fontana' were seeded into organic and mineral soil in 2002 and 2003 in the same plots. In 2002, N was applied at 0%, 50%, 100%, 150%, and 200% of current Ontario recommendations. Each experimental unit was split in half in 2003 with one half getting the same N rate as in 2002, and the second half getting no applied N. At harvest, total and marketable yield, weight per root, and quality were assessed. Yield and quality were unaffected by N rate in both mineral soil in 2002 and organic soil in both years. On mineral soil in 2003 there was a linear increase in total and marketable yield and weight per root with increasing N rate, with total yield ranging between 36 and 55 t/ha. However, in the treatments given no N in 2003, yield also increased from 36 to 47 t/ha between the 2002 no N and high N treatments. Consequently, a large portion of the increase in yield in 2003 on mineral soil was due to residual N from the previous season. Carrots are capable of taking up very high amounts of N from the soil over a growing season, but may only require additional N for maximum total yield if soil N content is low due to low mineralization rates or depletion by a previous crop. However, low N rates can reduce the ability to harvest the crop due to increased carrot leaf blight severity even when yield is unaffected.