bluuebunny/crossref_metadata_2025 huggingface dataset:
Response of Hazelnut Accessions to Greenhouse Inoculation with Anisogramma anomala
Authors: Sathuvalli Vidyasagar R. , Mehlenbacher Shawn A. , Smith David C.
Published: February 2019

Eastern filbert blight (EFB), caused by the pyrenomycete Anisogramma anomala (Peck) E. Müller, is a devastating disease of European hazelnut (Corylus avellana L.) in the Pacific Northwest. Host genetic resistance from ‘Gasaway’ has been used extensively for breeding hazelnuts at Oregon State University. Concern over the durability of this single-gene resistance prompted a search for new sources of resistance. In this study, 86 accessions from 11 countries were evaluated for their response to greenhouse inoculation with the pathogen. Nine accessions showed complete resistance, including one from Chile (‘Amarillo Tardio’), two from Serbia (‘Crvenje’ and ‘Uebov’), one from southern Russia (OSU 495.072) and five from Moscow, Russia. These new sources of EFB resistance have geographically diverse origins and will broaden the genetic base of EFB-resistant hazelnut germplasm. The previously reported resistance of ‘Grand Traverse’ from Michigan and the susceptibility of ‘Closca Molla’ from Spain were confirmed.
Poinsettia ‘Prestige™ Red’ (Euphorbia pulcherrima) In Vitro Propagation
Authors: Perera Dinum , Trader Brian W.
Published: February 2019

Slow growth rate of plantlets, few micro-shoots per explant, and slow root growth rate are restrictions of in vitro propagation of poinsettia (Euphorbia pulcherrima Willd. ex Koltz). The purpose of this research was to develop an efficient in vitro proliferation technique for poinsettia ‘Prestige™ Red’. Explants (apical buds and axillary buds) placed on Murashige and Skoog (MS) basal medium containing only 6-benzylaminopurine (BA) and combinations of BA and indole-3-acetic acid (IAA) mostly produced red callus, which is productive and some white and gray–green calluses at the base of plantlets after 1 month, whereas explants in a medium without plant growth regulators (PGRs) produced no callus. Addition of IAA into the rooting medium increased rooting efficiency; plantlets grown in half-strength MS salts and vitamins with 28.5 μM IAA initiated rooting 11 days earlier than the plantlets grown with no PGRs. Optimization of PGR concentrations during poinsettia micropropagation helped resolve previous restrictions of in vitro poinsettia proliferation. Chemical names used: 6-benzylaminopurine (BA); indole-3-acetic acid (IAA)
Development of a Prototype Bayesian Network Model Representing the Relationship between Fresh Market Yield and Some Agroclimatic Variables Known to Influence Storage Root Initiation in Sweetpotato
Authors: Villordon Arthur , Solis Julio , LaBonte Don , Clark Christopher
Published: February 2019

A prototype phenology-driven Bayesian belief network (BBN) model, named BxNET, was developed to represent the relationship between fresh market yield (U.S. #1 grade) and agroclimatic variables known to influence the critical storage root initiation stages in ‘Beauregard’ sweetpotato. This data-driven model was developed from experimental data collected over 3 years of field trials in which management variables were kept as uniform as possible. The BBN was developed assuming that soil moisture measured at the 15-cm depth was not a limiting variable during the first 20 days after transplanting, during which the onset of storage root initiation determined the majority of storage root yield at harvest. The absence of influence from weeds, disease, insect pests, and chemical injury was also assumed. Accuracy of the fully parameterized working prototype was estimated through leave-one-out cross-validation (14% error rate), validation on an independent test data set (20% error rate), and area under the receiving operator characteristic curve (0.59) analysis. As a result of its empirical nature, BxNET is only applicable to the cultivar, location, and the limited set of environmental (air temperature, soil temperature, relative humidity, solar radiation) and management variables as defined in the 3-year study. This beta-level model can serve as a foundation for the development of a final working model through further testing and validation. Additional validation data may require revision of the current model structure and conditional probabilities. These validation studies will also allow the model to be used in other locations. BxNET can be expanded to include other causal variables such as weed incidence, disease presence, insects, and chemical injury. Such an expansion can lead to the development of a model-based decision support system for sweetpotato production. Such a system can help model alternative management scenarios and determine the most reasonable management interventions to achieve optimum yield outcomes under different agroclimatic conditions.
Rapid Screening for Relative Salt Tolerance among Chile Pepper Genotypes
Authors: Niu Genhua , Rodriguez Denise S. , Crosby Kevin , Leskovar Daniel , Jifon John
Published: February 2019

Chile peppers are economically important crops in southern regions of the United States. Limited information is available on irrigation management with low-quality water or on salt-affected soils. The objective of this study was to determine the relative salt tolerance of 20 genotypes of chile peppers. In Expt. 1, seeds of selected pepper types (Anaheim, Ancho, Cayenne, Paprika, Jalapeño, Habanero, and Serrano) were germinated in potting mix and seedlings were grown in 2.6-L pots. Six weeks after sowing, salinity treatments were initiated by irrigating plants with nutrient solutions of different electrical conductivities (ECs): 1.4 (control), 3.0, or 6.0 dS·m−1. After 1 month of initiating treatments, shoots were harvested and dry weights were determined. All plants survived and no visual salt injury was observed regardless of pepper variety and treatment. There were no statistical differences between control and saline solution treatments in final height and shoot dry weight of Habanero 1, ‘Early Jalapeño’, ‘AZ-20’, ‘NuMex Joe E. Parker’, and ‘NuMex Sandia’. In Expt. 2, seeds of 20 genotypes were directly sown in 2.6-L containers filled with loamy sand. Saline water irrigation was initiated 37 days after sowing by irrigating plants either with saline (nutrient solution based, similar to Expt. 1) or nutrient solution (control). More than half the genotypes did not have 100% survival in the salinity treatment. Ancho 1, Ancho 2, Cayenne 1, ‘Early Jalapeño’, and ‘AZ-20’ had 100% survival regardless of salinity treatment. No plants of ‘TAM Mild Habanero’ survived when irrigated with saline water and less than half of the plants survived in the control. The relative tolerance of chile genotypes to salinity varied with substrate in some genotypes. From the combined results of the two experiments, the 20 pepper genotypes were ranked for salt tolerance based on seedling survival, visual quality, and growth. ‘Early Jalapeño’ and ‘AZ-20’ were relatively tolerant to salinity among the 20 genotypes, whereas ‘TAM Mild Habanero’ and ‘Ben Villalon’ were sensitive. Ancho 1, Ancho 2, Cayenne 1, and Cayenne 2 also had relatively high tolerance based on survival and visual quality, although shoot growth was reduced significantly.
Cross-amplification and Characterization of Microsatellite Loci for the Genus Rhododendron
Authors: Wang Xue-qin , Huang Yuan , Long Chun-lin
Published: February 2019

To assess cross-species amplification, we tested 38 microsatellite loci previously developed for Rhododendron delavayi Franch. and R. decorum Franch. in eight species representative of the genus Rhododendron. Sixteen pairs can be amplified successfully in all species, whereas two failed amplification in all species. Nine loci were polymorphic across six examined species with one to 11 alleles per locus. The observed and expected heterozygosity per locus varied from 0.07 to 0.65 and 0.44 to 0.81, respectively. Cross-application of these microsatellite loci will provide a potentially useful tool to investigate the genetic structure, gene flow, and evolutionary relationships in genus Rhododendron.
Water Relation Parameters of the Cortex Tissue of Fresh ‘Fuji’ Apple Fruit Determined by Centrifugation
Authors: Hou Xue-Min , Wang Zi-Hua , Deng Xi-Min , Li Guo-Hui
Published: February 2019

This experiment was carried out to obtain a pressure–volume (P-V) curve and Höfler diagram of the cortex tissue of fresh ‘Fuji’ apple fruit (Malus ×domestica Borkh.) with a novel centrifuge method. Based on the P-V curve and Höfler diagram, several water relation parameters of cortex tissue were determined and the interrelationship of these parameters was established. Turgor loss point (TLP) occurred at –1.74 MPa and 73.7% of relative water content (R*). At full hydration, osmotic potential (ψS) was –1.30 MPa and symplastic water accounted for 86.8% of R*. Bulk elastic modulus decreased linearly by 28% as pressure potential declined from 1.30 MPa at full hydration to zero at the TLP. This centrifuge technique can provide a simple and efficient way to determine water relation parameters of fleshy fruits.
Use of Combinations of Commercially Relevant O2 and CO2 Partial Pressures to Evaluate the Sensitivity of Nine Highbush Blueberry Fruit Cultivars to Controlled Atmospheres
Authors: Alsmairat Nihad , Contreras Carolina , Hancock James , Callow Pete , Beaudry Randolph
Published: February 2019

We tested the impact of storage atmospheres in which the CO2 and O2 percentages sum to 21% on highbush blueberry (Vaccinium corymbosum L.) fruit condition and quality. The CO2 and O2 combinations, in percent composition, were 19%/2%, 18%/3%, 16.5%/4.5%, 15%/6%, 13.5%/7.5%, 12%/9%, 6%/15%, and 0%/21% for CO2/O2, respectively. Nine blueberry cultivars were evaluated (Duke, Toro, Brigitta, Ozarkblue, Nelson, Liberty, Elliott, Legacy, and Jersey) after 8 weeks of controlled atmosphere (CA) storage at 0 °C. Surface mold, berry decay, skin reddening (associated with fruit pulp browning), fruit firmness, pulp discoloration, and the content of ethanol and acetaldehyde were assessed. Fruit firmness, skin reddening, and decay declined and the proportion of fruit with severe internal discoloration tended to increase as CO2 concentrations increased. Ethanol and acetaldehyde accumulation was minimal, indicating fermentation was not induced by the atmospheric conditions applied. Cultivar effects were far more pronounced than atmosphere effects. Some cultivars such as Duke, Toro, Brigitta, Liberty, and Legacy appear to be well suited to extended CA storage, whereas other cultivars such as Elliott stored moderately well, and Ozarkblue, Nelson, and Jersey stored poorly. The data indicate that responses to high levels of CO2, while O2 is maintained at its maximum level practicable, can, in a cultivar-dependent manner, include significant negative effects on quality while achieving the desired suppression of decay.
The Use of Soil Amendments to Improve Survival of Roadside Grasses
Authors: Brown Rebecca Nelson , Gorres Josef H.
Published: February 2019

Highway rights-of-way are routinely planted with turfgrasses to prevent erosion, filter runoff, and improve aesthetics. However, the roadside is a harsh environment, and perennial grasses often die within the first year, leading to bare ground and annual weeds, which do not prevent erosion during the winter. To improve the survival of perennial vegetation on the roadside, it is necessary to identify the factors limiting vegetation growth and then to either identify plants that can tolerate those factors or identify ways to ameliorate the stresses while still maintaining safety. This study was designed to evaluate the effects of improved cultivars, salt tolerance, and organic matter amendments on perennial grass survival along two highways in Rhode Island. The amendments tested were processed biosolids and composted yard waste, each applied in a 50:50 mixture by volume with existing roadside soil; plain soil was included as a control. We tested 20 improved turfgrass cultivars and one seed mixture with common creeping red fescue (Festuca rubra L.) as the standard. Turfgrass species tested were perennial ryegrass (Lolium perenne L.), tall fescue (Festuca arundinacea Schreb.), red fescue, alkali grass [Puccinellia distans (Jacq.) Parl.], idaho bentgrass (Agrostis idahoensis Nash), tufted hairgrass [Deschampsia cespitosa (L.) P. Beauv.], and kentucky bluegrass (Poa pratensis L.). We found that soil amendment was more effective than either improved genetics or salt tolerance. Establishment, vertical growth, and persistence of vegetation cover were significantly improved by amendment with organic matter, particularly biosolids. In Summer 2009 (the second growing season), turf cover exceeded 50% in the biosolids plots but was below 20% in the plain soil plots with complete loss of cover in the plain soil plots at one location. Kentucky bluegrass, tall fescue, red fescue, and idaho bentgrass showed the best persistence at the species level, and there were no consistent differences among cultivars.
From Villous Strawberry Shams to Hairy Huckleberries: The Wild Side of Berry Exploration
Authors: Hummer Kim E.
Published: February 2019

The U.S. Department of Agriculture (USDA), Agricultural Research Service, National Clonal Germplasm Repository in Corvallis was established as the U.S. National Plant Germplasm System's berry genebank in 1981. Since then, the USDA has sponsored numerous explorations throughout the United States and foreign countries to obtain berry plant genetic resources. Species of Fragaria L. (strawberries), Ribes L. (currants and gooseberries), Rubus L. (raspberries and blackberries), and Vaccinium L. (blueberries and cranberries) are native to both domestic and international localities. With limited gene pools for cultivated strawberries, raspberries, and blackberries, expeditions have provided a wealth of genetic resources to expand opportunities for breeders to develop new cultivars. Particularly given the diverse species inherent in the development of cultivated blueberries, these trips have discovered unusual new blueberry relatives and forms available for expanding the range of production, increasing plant yields, and improving fruit antioxidant content. Along the way, new fruit species and new uses for known species were observed. Gathering the bounty of the world's berries resulted in encounters with diverse fauna, from snakes, bears, and bison to butterflies, mosquitoes, ticks, and chiggers. Avenging Toxicodendron species have added their mark on intrepid explorers. Remote sites with nothing but clear night stars and the satellite markers on the global positioning system offer radiant beauty and an abiding hope for the conservation of plant genetic diversity for all people for all time.
Evaluation of a Subset of the Solanum lycopersicum var. cerasiforme Core Collection for Horticultural Quality and Fruit Phenolic Content
Authors: Boches Peter , Peterschmidt Brooke , Myers James R.
Published: February 2019

One hundred S. l. var. cerasiforme (Dunal) accessions from the ‘Tanksley’ designated core collection were evaluated for horticultural quality under greenhouse conditions. Fourteen selected accessions were grown under field conditions in a replicated trial to evaluate the fruit for phenolic content. Total fruit phenolics ranged from 44 to 82 mg/100 g gallic acid equivalents (GAE) fresh weight (FW) as measured by Folin-Ciocalteau assay (F-C), and 12 to 108 mg/100 g FW as measured by high-performance liquid chromatography (HPLC). Five accessions (LA1712, LA1455, LA2633, LA1668, and LA2632) had significantly higher total phenolics (F-C) than cultivars (P ≤ 0.05). These five accessions also possessed interesting phenolics profiles, including high levels of caffeoylquinic acids (LA1620, LA1455, and LA2633) and rutin (LA2633).
Study on Shrimp Waste Water and Vermicompost as a Nutrient Source for Bell Peppers
Authors: Zheljazkov Valtcho D. , Horgan Thomas E. , Astatkie Tess , Fratesi Dolores , Mischke Charles C.
Published: February 2019

The aquaculture industry generates significant nutrient-rich wastewater that is released into streams and rivers causing environmental concern. The objective of this controlled environment study was to evaluate the effect of waste shrimp water (SW), vermicompost (VC), at rates of 10%, 20%, 40%, and 80% by volume alone or in combination with SW, controlled-release fertilizer (CRF), and water-soluble fertilizer (WSF) on bell peppers (Capsicum annuum L.) cv. X3R Red Knight. Application of VC at 80% or SW alone increased yields relative to unfertilized control. Combined applications of VC and SW increased yields compared with VC alone. Overall, total yields were greatest in the chemical fertilizer treatments (CRF and WSF) and least in the unfertilized control. SW and VC increased growth medium pH relative to the unfertilized control or to the chemical fertilizer treatments. In pepper fruits, the greatest nitrogen (N) content was found in the CRF treatment, although it was not different from VC at high rates or WSF treatments. Phosphorus concentration in peppers was greatest in the CRF treatment, less in all VC or SW treatments, but not different from unfertilized control or WSF treatment. Iron, magnesium (Mg), and zinc concentrations in peppers were greatest in CRF treatment but not different from control or WSF treatments. Overall, N accumulation in peppers was negatively correlated to growth medium pH and calcium (Ca); phosphorus (P) in peppers was negatively correlated to growth medium pH, Ca, and sodium (Na), whereas potassium (K) in peppers was negatively correlated to growth medium P, Mg, and Na. Results indicated: 1) SW may not be a viable pepper nutrient source; (2) SW can provide a similar nutrient supply as VC; and (3) chemical fertilizers can provide higher pepper yields compared with SW or VC alone or in combination.
Screening Bermudagrass Germplasm Accessions for Tolerance to Sting Nematodes
Authors: Pang Wenjing , Luc John E. , Crow William T. , Kenworthy Kevin E. , McSorley Robert , Giblin-Davis Robin M.
Published: February 2019

Breeding and improvement of new bermudagrass (Cynodon spp.) cultivars with superior nematode tolerance are essential because sting nematode (Belonolaimus longicaudatus Rau) is a major limitation for use of bermudagrass in the sandy coastal soils of the southeastern United States. The screening of both African (Cynodon transvaalensis) and common (C. dactylon) bermudagrass is necessary to develop triploid hybrid cultivars. Five commercial cultivars and 46 germplasm accessions of bermudagrass were tested for nematode responses in two greenhouse trials in 2009. Turfgrass was grown in sand-filled plastic conetainers and inoculated with 50 sting nematodes per conetainer. Nematode and root samples were collected 90 d after nematode inoculation. Fifteen bermudagrass accessions did not have measurable root loss from inoculation with sting nematode. Seven bermudagrass accessions, including ‘Celebration’, produced longer roots in sting nematode-infested soil than the standard ‘Tifway’. Differences in final nematode numbers were identified among the genotypes, and different relative responses were identified in variable ploidy levels and origins. This could aid a turfgrass breeding program by elucidating the genetic diversity available for breeding future bermudagrass cultivars for golf course cultivation.
Storage Temperature and Moisture Content Affect Respiration and Survival of Ranunculus asiaticus Dry Tuberous Roots
Authors: Cerveny Christopher B. , Miller William B. , Taylor Alan G.
Published: February 2019

Ranunculus asiaticus (L.) is an ornamental geophyte with some commercial production challenges presumed to be related to the storage of its desiccation tolerant tuberous roots (TRs). We investigated the influence of temperature and relative humidity during storage on viability of R. asiaticus TRs. The TRs were stored in specialized chambers for controlling relative humidity under flow-through or closed systems. In the flow-through system, air was bubbled through glycerol–water solutions to create relative humidities of 20%, 40%, 60%, 80%, or 100% and then passed through storage chambers held at 5, 20, or 35 °C for up to 20 weeks. In closed storage, tissue was equilibrated to a given moisture content (fresh basis) at 15 °C by suspending TRs over glycerol–water solutions (35%, 60%, or 85% relative humidity) with fans to circulate air. These containers were closed for 4 weeks and then tissue was transferred to sealed jars for up to 17 weeks at 5 or 25 °C. In both systems, TRs held with elevated temperature and relative humidity had the largest decrease in percent survival when planted after storage. Flow-through storage gave greater variability in TRs moisture content than closed storage. Tuberous roots at 25 °C had higher respiration rates than at 5 °C under closed storage; elevated moisture content also led to increased respiration. From these results it can be concluded that R. asiaticus dry TRs should be stored cool and dry for long-term viability.
Low-temperature Nitrogen Uptake and Use of Three Cool-season Turfgrasses under Controlled Environments
Authors: Lloyd Daniel T. , Soldat Douglas J. , Stier John C.
Published: February 2019

Fall fertilization of turfgrass in northern climates is often considered to be agronomically beneficial, although research on nitrogen (N) uptake during cold temperatures is sparse and environmental concerns exist regarding nitrate leaching. Therefore, the objective of this study was to evaluate N uptake potential, use, and plant metabolic response in a climate-controlled environment evaluating the responses of various cool-season turfgrass species to variable N rates and temperature regimens. Creeping bentgrass (Agrostis stolonifera L.), kentucky bluegrass (Poa pratensis L.), and annual bluegrass (Poa annua var. reptans L.) were seeded and grown for 3 months and then acclimated in a growth chamber to one of three climate regimens corresponding to 15 Sept., 15 Oct., and 15 Nov. in Madison, WI. Grasses were fertilized at 0, 25, 49, or 98 kg·ha−1 N with 15N-labeled ammonium sulfate (10 atom % 15N) by applying a liquid solution of 75 mL per pot (1 cm of solution in depth). Data collected included verdure biomass, root mass, net canopy photosynthesis, and 15N fertilizer uptake. For all turfgrass species, shoot growth increased in response to N application in the September regimen, but not in October or November regimens. N uptake was significantly lower in the November regimen compared with September with an average of 73% of fertilizer recovery in September compared with 57% and 38% in October and November, respectively. Root mass and net canopy photosynthesis were greatest in the November treatments, although these responses were generally unaffected by N application rate. The results of this study indicate that N uptake capacity is greatly reduced as average daily temperatures approach 0 °C. Nitrogen application rates should be adjusted downward to maximize uptake efficiency in cold temperatures.
Genetic Resistance in Melon PI 313970 to Cucurbit yellow stunting disorder virus
Authors: McCreight James D. , Wintermantel William M.
Published: February 2019

Melon (Cucumis melo L.) is a fresh vegetable and dessert fruit that may also be cooked or dried, processed for juice and flavoring, and the seeds of which are a source of high-quality cooking oil and high protein seed meal. Melon production throughout many parts of the world is now threatened by the crinivirus Cucurbit yellow stunting disorder virus (CYSDV) in tropical and subtropical areas favorable to its whitefly vector. CYSDV is transmitted by the sweetpotato whitefly, Bemisia tabaci Gennadius, biotypes A, B, and Q. CYSDV first appeared on melon in the 1980s in the United Arab Emirates and emerged on melon in the Yuma, AZ, and Imperial Valley, CA, regions and western Mexico during the Fall season of 2006 followed by Florida in 2007. PI 313970, C. melo var. acidulus Naudin, a salad-type melon from India, expressed high-level resistance to CYSDV in Yuma and Imperial Valley in Fall 2006, but it was not immune; the virus was detected in asymptomatic plants. Inheritance of resistance to CYSDV in PI 313970 was studied in three naturally infected, replicated field tests in Imperial Valley during the Fall seasons of 2007 and 2008 and the Spring season of 2009. Resistance in PI 313970 was recessive: all F1 PI 313970 (PI) × susceptible ‘Top Mark’ (TM) and BCTM individuals were susceptible, and the F2 and BCPI segregated 3:1 and 1:1 susceptible to resistance, respectively. Frequency distributions of CYSDV symptom severity ratings suggested a single recessive gene in PI 313970 for resistance to CYSDV. PI 313970 was, however, observed to be variable for resistance; a few plants in each test expressed distinct symptoms of CYSDV infection and its frequency distributions overlapped those of ‘Top Mark’. This variation may represent genetic variation selectable for uniform reaction to infection by CYSDV or phenotypic variation in the resistant reaction. The genetic relationship between the genes for resistance to CYSDV in PI 313970 (recessive) and TGR-1551 (dominant) is not known.
In Vitro Selection of a Salt-tolerant Embryogenic Line in Habanero Pepper (Capsicum chinense Jacq.)
Authors: Solís-Marroquín Daniela , Lecona-Guzmán Carlos Alberto , Canto-Flick Adriana , Bello-Bello Jericó Jabín , Santana-Buzzy Nancy , Iglesias-Andreu Lourdes
Published: February 2019

The effect of NaCI salinity on growth and development of somatic embryos of Habanero pepper was examined. Addition of 75 and 100 mm NaCI into the medium greatly increased the growth and development of somatic embryos and both of these concentrations favored the proliferation of somatic embryos. However, supplementation of 200 and 300 mm NaCI to the medium showed a negative effect on the growth and development of somatic embryos. Concentration increases of NaCl provoked a significant reduction of the embryos survival rate with the average lethal dose (46%) being registered in the treatment of 100 mm. Furthermore, a lower tolerance to salt stress (NaCl) was observed in deformed somatic embryos. Concentrations of 200 and 300 mm NaCl significantly delayed development in the surviving embryos in both treatments. These embryos remained at the globular stage throughout culture time. At 75 mm NaCl, most of the embryos were observed in the torpedo stage. However, the embryos exposed to 100 mm NaCl were observed mainly in globular and cotiledonar stages. It is quite likely that the transition from one intermediate stage of development to another occurs rapidly. With the exception of the concentration at 300 mm NaCl, salt stress stimulated embryonic germination, particularly at 100 mm NaCl. The content of proline in somatic embryos increased substantially in response to salinization. The results suggest that somatic embryos of C. chinense can tolerate concentrations of NaCl up to 100 mm without their development being affected. Moreover, they have sufficient cellular mechanisms to tolerate salinity at relatively higher levels.
Calla Lily Growth and Development Under Saline Irrigation
Authors: Veatch-Blohm Maren E. , Morningstar Lindsay
Published: February 2019

Salinity is a problem for crop production worldwide, which can affect not only the yield of ornamental plants, but also their quality. Calla lilies (Zantedeschia K. Koch) are a popular cut flower and landscape plant. In this study we examined how salinity applied either pre- or post-emergence altered shoot growth and flower production compared with standard growth conditions. Salinity applied post-emergence did not significantly affect shoot growth in either the 25- or 50-mm NaCl treatments; however, irrigation with a 50-mm NaCl solution did significantly reduce dry weight and flower production compared with the control. The most drastic effect on flower production was observed when the 50-mm treatment was applied pre-emergence. Although flowering time did not vary among treatments, in the spring, flowering success was less than 50% in the 50-mm treatment, which was significantly less than the other treatments. The plants in all treatments had good visual quality and high relative water content although the shoots of the salt-stressed plants had a Na+ content two to five times greater than the control. We hypothesize that the maintenance of visual quality may in part be the result of increased Ca2+ concentration (up to four times the amount in the control) in the shoots of the salt-stressed plants, which may have helped maintain turgor and cell membrane integrity under saline conditions. Our results indicate that use of irrigation water salinized by NaCl with an electrical conductivity (EC) more than twice as high as that recommended for optimal calla growth (1.5 dS·m−1 compared with 3.4 dS·m−1) can be used without a loss in plant quality, thereby increasing irrigation options for calla lilies, particularly in areas where high-quality water is scarce.
Performance of Apple (Malus ×domestica Borkh.) Cultivars Grown in Different Chilean Regions on a Six-year Trial, Part I: Vegetative Growth, Yield, and Phenology
Authors: Yuri Jose A. , Moggia Claudia , Torres Carolina A. , Sepulveda Alvaro , Lepe Valeria , Vasquez Jose L.
Published: February 2019

Performance of seven apple (Malus ×domestica Borkh.) cultivars (‘Brookfield®Gala’, ‘Galaxy’, ‘Super Chief’, ‘Granny Smith’, ‘Fuji Raku Raku’, ‘Cripp's Pink’, and ‘Braeburn’) on M.M.106 and M.9 EMLA rootstocks during their first 6 years was evaluated on a multisite trial in Chile. Second-leaf trees were planted in experimental blocks inside commercial orchards located in five major apple-producing areas in Chile (Graneros, San Clemente, Chillan, Angol, and Temuco). Tree height and volume, trunk cross-sectional area (TCA), fruit yield and size distribution, crop load, and tree phenology were assessed annually. In general, tree growth rates by the end of the third year, when they reached the desired height, were similar in all block locations. M.9 EMLA rootstock reduced tree height by ≈20% in ‘Brookfield® Gala’, ‘Fuji’, ‘Galaxy’, and ‘Granny Smith’. This rootstock also had 50% smaller TCAs than M.M.106’s at Year 6 in most cultivars. The highest productions in ‘Brookfield®Gala’, ‘Galaxy’, ‘Granny Smith’, ‘Cripp's Pink’, and ‘Super Chief’, regardless of rootstock, were obtained in San Clemente and Chillan's blocks. Although M.M. 106 trees delivered higher yields per plant, M.9 EMLA yield efficiency (no. fruit/cm2 TCA) was significantly higher. In general, the higher the latitude (toward south), the later budbreak, full bloom, and harvest occurred.
Reduced Nitrogen, Phosphorus, and Potassium Rates for Intermediate-day Onion in Paddy Soil with Incorporated Rice Straw plus Manure
Authors: Lee Jongtae , Moon Jinseong , Kim Heedae , Ha Injong , Lee Sangdae
Published: February 2019

The effect of nitrogen (N), phosphorus (P), and potassium (K) supply on the growth and nutrient uptake of intermediate-day onions (Allium cepa L.) was investigated in a double cropping system of rice and onion in which rice straw had been annually applied. The experiment consisted of three sets of treatments: N (0, 120, 240, 360 kg·ha−1 N), P (0, 18, 35, 52 kg·ha−1), and K (0, 67, 133, 200 kg·ha−1) with the addition of 8.0 t·ha−1 of decomposed pig manure. The rice straw was incorporated with tillage after harvest. Foliage weight of the onion plant was affected by N rate on 21 Apr. and on 23 May. Bulb weight was also influenced by N rate on 23 May and at harvest. The only difference (P ≤ 0.05) in onion yield was observed between the zero N rate and all the other N levels. Soil pH was correlated with rate of N fertilization. Soil NO3-N for 240 and 360 kg·ha−1 N rates ranged from 36.6 to 113.7 and 49.9 to 148.6 mg·kg−1, respectively, which was at least twice as high as that at 120 kg·ha−1 N rate. The highest fertilizer use efficiency of nitrogen was 36.0% at 120 kg·ha−1 followed by 240 kg·ha−1 at 28.0% and 360 kg·ha−1 at 20.6%. There was no clear effect of P or K rates on P or K concentration in the onion bulbs. K concentration and uptake in the onion leaf tissue increased with higher K rates. In conclusion, compost and rice straw provided sufficient P and K to grow onions without additional P and K fertilizer, and under these conditions, the fertilizer level of 120 kg·ha−1 N produced as much onion bulb yield as higher N levels.
Using a Scanner-based Minirhizotron System to Characterize Sweetpotato Adventitious Root Development during the Initial Storage Root Bulking Stage
Authors: Villordon Arthur , LaBonte Don , Solis Julio
Published: February 2019

A scanner-based minirhizotron (MR) system detected initial adventitious root (AR) development associated with transplant establishment. The system also documented the transition of ARs into pencil roots (PRs) and, in some cases, storage roots (SRs). In general, the MR system underestimated destructive sampling-based (DS) estimates of newly initiated AR (NAR), PR, and SR counts. Angled or vertical single sampling tubes underestimated NAR count by 85% and 79%, respectively. Regardless of installation position, single tube-based measurements underestimated PR and SR count by 83% and 95%, respectively. However, it was found that two vertically installed tubes underestimated NAR count by only 48%. The potential ability of paired sampling tubes to discriminate NAR count differences in response to experimental treatments was confirmed in a simple rain shelter experiment. The paired MR and DS systems detected 83% and 56% reduction in NAR count among plots with rain shelters, respectively. However, it appeared that the presence of tubes interfered with SR formation of monitored AR segments. Despite this limitation, the results show the potential for incorporating MR systems in ongoing and future studies that aim to qualitatively and quantitatively document sweetpotato AR system response to agroclimatic variables and management interventions during the initial SR bulking stage.
Growth and Ion Distribution Is Affected by Irrigation with Saline Water in Selected Landscape Species Grown in Two Consecutive Growing Seasons: Spring–summer and Fall–winter
Authors: Valdez-Aguilar Luis A. , Grieve Catherine M. , Razak-Mahar Abdul , McGiffen Milton E. , Merhaut Donald J.
Published: February 2019

Landscape irrigation is the second largest user of reclaimed water in industrialized countries; however, its high concentration of soluble salts, especially Na+ and Cl–, may induce growth reduction and leaf necrosis or bronzing in ornamental species. The present study was conducted to determine the growth and quality responses and nutritional ion imbalances of selected landscape species during the container production phase when subjected to irrigation with water of increasing NaCl + CaCl2 concentrations. Plants of boxwood [Buxus microphylla var. japonica (Mull. Arg. ex Miq) Rehder & E.H. Wilson], escallonia (Escallonia ×exoniensis hort. Veich ex Bean), hawthorn [Raphiolepis indica (L.) Lind. Ex Ker Gawl. × ‘Montic’], hibiscus (Hibiscus rosa-sinensis L.), and juniper (Juniperus chinensis L.) were grown in a greenhouse in the Spring–Summer and in the Fall–Winter in separate experiments. Saline irrigation consisted of solutions with electrical conductivities (ECiw) of 0.6, 2, 4, 6, and 8 dS·m−1 in the Spring–Summer experiment and 0.6, 4, 6, 8, and 12 dS·m−1 in the Fall–Winter. Growth of the five species decreased when irrigated with saline waters. Leaf growth was highly sensitive to salinity and the average decrease in leaf dry weight was the criterion used to rank the tolerance of the species. In the Spring–Summer experiment, the ranking was (higher tolerance to lower tolerance): juniper ∼ boxwood > escallonia > hawthorn > hibiscus, whereas in Fall–Winter, the ranking was: juniper ∼ boxwood > hibiscus > escallonia > hawthorn. The species were ranked according to their visual attractiveness in the Spring–Summer experiment. The threshold ECiw at which visual attractiveness was affected gave the following ranking (higher to lower tolerance): hibiscus > juniper > escallonia > hawthorn > boxwood. Estimating the EC of drainage water from threshold ECiw, boxwood was classified as sensitive, hawthorn as moderately sensitive, escallonia as moderately tolerant, and hibiscus and juniper as highly tolerant. Tolerance of juniper was ascribed to Na+ and Cl– retention in the roots observed in both growing seasons and to the higher root biomass that allowed a higher accumulation of salts in this organ, preventing translocation to the leaves. Although boxwood exhibited acceptable tolerance in terms of growth, visual quality severely decreased; in contrast, growth of hibiscus was the most severely reduced but was rated as the most tolerant species in terms of visual quality. This opposite response may be the result of an excellent capacity to compartmentalize salts in hibiscus, whereas in boxwood, this mechanism may be absent.
Variation in the Breeding System of Prunella vulgaris L.
Authors: Qu Luping , Widrlechner Mark P.
Published: February 2019

Prunella vulgaris (Lamiaceae), commonly known as selfheal, is a perennial herb with a long history of use in traditional medicine. Recent studies have found that P. vulgaris possesses anti-inflammatory, antiviral, and antibacterial properties, and it is likely that this will lead to increased commercial demand for this species. To date, research publications on P. vulgaris cultivation and genetics are scarce. Using accessions originally collected from different geographical regions, we investigated the breeding system of this species by observing variation in floral morphology, time of pollen release, and selfed-seed set in bagged flowers and isolated plants. Two types of floral morphology, one with exerted styles, extending past open corollas when viewed from above, and the other with shorter, inserted styles, were found among 30 accessions. Two accessions originally collected from Asia uniformly displayed exerted styles, and 27 accessions had inserted styles. One accession from Oregon displayed variation in this trait among individual plants. Microscopic observation of seven accessions, including ones with both exerted and inserted styles, revealed that they all release pollen to some degree before the flowers open. Using bagged flowers, we found that selfed-seed set varied widely among eight accessions, ranging from 6% to 94%. However, bagging may underestimate seed set for some accessions. The two accessions with the lowest rates when using bagged flowers increased in seed set by 350% and 158%, respectively, when we evaluated single, unbagged plants in isolation cages. The accession with 6% selfed-seed set when bagged also had exerted styles. These findings suggest that mating systems in P. vulgaris may be in the process of evolutionary change and that understanding breeding-system variation should be useful in developing efficient seed-regeneration protocols and breeding and selection strategies for this species.
Changes in Endogenous Auxin Concentration in Cultivars of Tomato Seedlings under Artificial Light
Authors: Almansa Eva María , Espín Antonio , Chica Rosa María , Lao María Teresa
Published: February 2019

In this work, we present the study of the behavior of 15 tomato cultivars under different grow lights to evaluate the quality of seedlings in the production system. The lamps used are: compact fluorescent, high-efficiency fluorescent, fluorescent, and pure blue light-emitting diodes (B-LEDs). The trial was carried out in a culture chamber with the temperature and relative humidity continuously controlled. Spectral radiation was measured at the canopy level. The following were quantified: fresh, dry biomass partitioning organs (leaves, stems, and roots), the total dry weight/total fresh weight relationship, shoot/root ratio, and indole acetic acid. We found high-efficiency fluorescent light treatment has a very interesting spectral quality for all cultivar applications as a result of it having the lowest photosynthetically active radiation (PAR):near infrared (NIR), blue:red (B:R), blue:far red (B:FR), and red:far red (R:FR) ratios; ‘Conquista’, ‘Velasco’, and ‘Lynna’ are cultivars that show sensitivity to special wavebands (ultraviolet, B, R, and FR). ‘Ikram’, ‘Saladar’, and ‘Delizia’ tolerate the lack of minimum energy and spectral quality.
Field Survey and Fungicide Screening of Fungal Pathogens of Rambutan (Nephelium lappaceum) Fruit Rot in Hawaii
Authors: Keith Lisa , Matsumoto Tracie , Nishijima Kate , Wall Marisa , Nagao Mike
Published: February 2019

Rambutan (Nephelium lappaceum Linn.) is a tropical fruit in Hawaii that has increased in value in the niche market of exotic fruits. The primary limitation to preharvest and postharvest quality is the occurrence of fungal diseases of the fruit. A survey of rambutan disease was conducted at orchards 9.7 km south and 29.0 km north of Hilo, HI, to determine the main fungal pathogens affecting preharvest fruit quality. Pericarp of rambutan fruit revealed brown to black lesions that progressed to blackening and drying of the fruit with some fruits becoming totally mummified. Four fungi consistently isolated from symptomatic fruit included Lasmenia, Pestalotiopsis, Phomopsis, and Colletotrichum spp. Over the 2-year sampling period, disease incidence from more than 300 fruits sampled was 84.6%. Nine rambutan cultivars were evaluated for disease incidence under field conditions. Disease incidence was greater than 90% for ‘Sitangku’ and ‘R167’ but less than 60% for ‘Chompoo’. Twelve fungal isolates from infected fruit were selected for further characterization (six Lasmenia isolates and two isolates each of Pestalotiopsis, Phomopsis, and Colletotrichum). Morphology, colony characteristics, and pathogenicity of the isolates were examined. The optimum growth temperature for all fungal isolates ranged between 22 and 28 °C. Molecular methods were used to confirm the identity of the fungi. The fungal isolates were evaluated for in vitro baseline sensitivities for mycelial growth for fungicides registered for use in Hawaii (Abound® and Trilogy®). Abound® was more effective at inhibiting fungal growth than was Trilogy®; however, efficacy appeared to be influenced by fungal genera. Inhibition of fungal growth by Abound® ranged from a 76% reduction for Lasmenia to a 23% reduction for Phomopsis isolates.
People–plant Relationships in an Office Workplace: Perceived Benefits for the Workplace and Employees
Authors: Thomsen Jane Dyrhauge , Sønderstrup-Andersen Hans K.H. , Müller Renate
Published: February 2019

The study presented in this article represents an initial attempt to generate in-depth information about how ornamental plants in real-life office workplaces interact with workplace characteristics, thus influencing working environment and well-being of the employees. Using a qualitative, explorative, and inductive case-study design, the study provides an example of how a cross-disciplinary unit engaged in administrative office work at a Danish institution applied ornamental plants. The results document that ornamental plants are an integrated part of the workplace. The employees used ornamental plants in numerous ways to either actively manipulate different aspects of the surroundings or more passively cope with demands from the surroundings. Furthermore, the use of the ornamental plants was structured by a number of factors: culture and traditions, provisional orders, organizational structures, practices, values and history, company policies, and characteristics of the indoor architectural environment. Ornamental plants were perceived as affecting many aspects of the working environment (e.g., the physical surroundings, the social climate, image of the workplace, etc.), the individual's well-being (e.g., mood, general well-being, emotions, self confidence, etc.), and to some degree the workplace's competitiveness. However, the actual effects were the results of a complex interaction among the way the ornamental plants were applied, characteristics of the present ornamental plants (e.g., size, species and condition), and characteristics of the individual employee (e.g., personal experiences, preferences, and values).
Cardinal Temperatures and Thermal Time for Seed Germination of Brunonia australis (Goodeniaceae) and Calandrinia sp. (Portulacaceae)
Authors: Cave Robyn L. , Birch Colin J. , Hammer Graeme L. , Erwin John E. , Johnston Margaret E.
Published: February 2019

Seed germination of Brunonia australis Sm. ex R.Br. and Calandrinia sp. (Mt. Clere: not yet fully classified) was investigated using a thermogradient plate set at different constant temperatures to determine seed propagation requirements of these potential floriculture species. Germination responses were tested at 3, 7, 11, 15, 18, 22, 25, 29, 34, and 38 °C. Germination data were modeled using the cumulative distribution function of the inverse normal, which provides information on lag, rate, and maximum seed germination for each temperature regime. To determine cardinal temperatures, the reciprocal time to median germination (1/t50) and percentage germination per day were calculated and regressed against temperature. Base temperature estimates for B. australis were 4.9 and 5.5 °C and optimum temperatures were 21.4 and 21.9 °C, whereas maximum temperatures were 35.9 and 103.5 °C, with the latter being clearly overestimated using the 1/t50 index. Base temperatures for Calandrinia sp. were 5.8 and 7.9 °C, whereas optimum and maximum temperature estimates of 22.5 and 42.7 °C, respectively, were reported using the percentage germination per day index. Maximum seed germination of 0.8 to 0.9, expressed as the probability of a seed germinating, occurred at 11 to 25 °C for B. australis, whereas maximum germination for Calandrinia sp. was 0.5 to 0.7 at 18 to 25 °C. Thermal time, the accumulation of daily mean temperate above a base temperature, was calculated for different germination percentages. Estimates of thermal time (°Cd) for 50% seed germination were 54 and 90 °Cd for B. australis and Calandrinia sp., respectively.
Water and Nutrient Uptake and Use Efficiency with Partial Saturation Ebb and Flow Watering
Authors: Gent Martin P.N. , McAvoy Richard J.
Published: February 2019

Subirrigation for production of potted ornamental plants reduces the waste of water and fertilizer inherent to conventional overhead watering systems used in greenhouses. Ebb and flow watering systems for flooded floors typically operate slowly so that the substrate takes up water to near effective water-holding capacity during each irrigation event. We used a system that rapidly delivered water to and removed water from the production surface to restrict the water provided to the plants. We examined several parameters that vary between this fast-cycle ebb and flow watering on a flooded floor compared with slow-cycle watering. Water and fertilizer use was reduced by 20% to 30% with fast- compared with slow-cycle watering. Biomass and stem height at bloom were also reduced by 10% to 20% under fast-cycle saturation. This watering method did not affect the rate of flower development or plant nutrient composition. Volumetric water content of the substrate was the only measure that was affected by location on the flooded floor. Despite the fast ebb and flow on pitched floors, none of the aspects of plant growth was affected by location on the floor. This method of watering shows promise as a means to produce uniform crops of container-grown plants while conserving water and fertilizer.