bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Biochar Type on Macronutrient Retention and Release from Soilless Substrate
Authors: Altland James E. , Locke James C.
Published: February 2019

A series of column studies were conducted to determine the influence of three different biochar types on nitrate, phosphate, and potassium retention and leaching in a typical greenhouse soilless substrate. A commercial substrate composed of 85 sphagnum peatmoss : 15 perlite (v:v) was amended with 10% by volume of three different biochar types including: gasified rice hull biochar (GRHB), sawdust biochar (SDB), and a bark and wood biochar (BWB). The non-amended control substrate, along with substrates amended with one of three biochar materials, were each packed into three columns. Columns were drenched with nutrient solution and leached to determine the impact of biochar on nutrient retention and leaching. Nitrate release curves were exponential and peaked lower, at later leaching events, and had higher residual nitrate release over time with each biochar amendment. The impact of biochar amendment on phosphate retention and release was more variable within and across the two experiments. In both experiments, the GRHB was a net source of phosphate, providing more phosphate to the system than the fertilizer application and hence obscuring any retention and release effect it might have. Potassium release varied by amendment type within each experiment, but within each amendment type was relatively consistent across the two experiments. All biochar types were a source of potassium, with GRHB providing more than SDB, but both providing far more potassium than the fertilizer event. The BWB amendment resulted in more leached potassium than the control substrate, but relatively little compared with GRHB and SDB amendments.
Discovery and Characterization of a Turf-type Triploid Seashore Paspalum
Authors: Schwartz Brian M. , Contreras Ryan N. , Harris-Shultz Karen R. , Heckart Douglas L. , Peake Jason B. , Raymer Paul L.
Published: February 2019

Seashore paspalum is a salt tolerant, predominately diploid (2n = 2x = 20) species that is well adapted to coastal regions in tropical and subtropical environments. Because a majority of the available cultivars are propagated vegetatively and most genotypes are cross-fertile, a sterile cultivar that does not produce segregating seedlings would benefit sod growers and turfgrass managers who demand uniformity for certification and performance. Therefore, an experiment was conducted to create a colchicine-induced polyploid seashore paspalum. One triploid (2n = 3x = 30) genotype (11-TSP-1) was identified and remains stable. Although there is a possibility that this event was triggered by the colchicine treatment, a more likely explanation is that it resulted from the union of a reduced and an unreduced gamete. Pollen shed was observed from 11-TSP-1 in 2011, but individual pollen grains stained with iodine–potassium iodide were irregularly shaped and typically had lower starch content than pollen from several diploid cultivars. The leaf width of 11-TSP-1 was statistically equal to that of the seashore paspalum cultivar SeaStar, indicating its potential for use as a fine turf. 11-TSP-1 had both superior visual color and a dark green color index when compared with ‘SeaStar’. Future study of the reproductive fertility and more extensive field testing of this genotype should be carried out to determine its turfgrass potential. Chemical names used: 4′, 6-diamidino-2-phenylindole (DAPI), dimethyl sulfoxide (DMSO), iodine-potassium iodide (I2-KI), propidium iodide (PI).
Genetic Relationships of Wild Roses, Old Garden Roses, and Modern Roses Based on Internal Transcribed Spacers and matK Sequences
Authors: Qiu Xianqin , Zhang Hao , Jian Hongying , Wang Qigang , Zhou Ningning , Yan Huijun , Zhang Ting , Tang Kaixue
Published: February 2019

Roses are one of the economically most important groups of ornamental plants. The internal transcribed spacers (ITS) of the nuclear ribosomal DNA and the chloroplast gene matK were used to investigate the genetic diversity and genetic relationships among Rosa germplasm including 39 wild species, 21 old garden roses, and 29 modern cultivars. Three dendrograms based on ITS and matK clustering data indicated that 1) 39 wild genotypes were consistent with their classification into botanical sections with only a few exceptions; 2) most of the wild genotypes were separated from rose cultivars. However, three sections, Synstylae, Chinenses, and Rosa, that contributed to the modern roses generally gathered together with almost all old garden and modern roses on the molecular level; and 3) the relationships between cultivated roses as inferred by ITS and matK sequences do not correlate with horticultural groups. Results demonstrated that both sequence techniques can contribute to clarifying the genetic relationships of rose accessions and germplasm conservation to enhance the ornamental and economic value of rose.
Blueberry Floral Attributes and Their Effect on the Pollination Efficiency of an Oligolectic Bee, Osmia ribifloris Cockerell (Megachilidae: Apoidea)
Authors: Sampson Blair J. , Stringer Stephen J. , Marshall Donna A.
Published: February 2019

We evaluated relationships between floral traits of 23 genotypes of southern blueberries and indices of pollination efficiency (fruit set, fruit abortion, seed number, and berry size) for Osmia ribifloris Cockerell, a manageable solitary bee. Flower size in Vaccinium and presumably ovary size were proportional to berry size, except for the tiny blooms of one V. tenellum clone (NC7808), which produce large commercial-sized berries of ≈2 g. Longer-styled blueberry flowers visited by O. ribifloris produced the heaviest berries with the most seeds. Osmia ribifloris reliably pollinated ‘Climax’ and ‘Tifblue’ rabbiteye blueberries. However, the peculiarly misshapen blooms of ‘Premier’ rabbiteye blueberry receive less pollination from O. ribifloris and yield berries containing 25% fewer seeds. Fruit set for these misshapen ‘Premier’ flowers was equivalent to that of intact flowers indicating that this floral polymorphism would not greatly alter cultivar performance. For seven Vaccinium species, wild and cultivated alike, 80% to 100% of a plant’s fruit production depends on efficient cross-pollination by bees such as O. ribifloris.
Potential Sources of Resistance in U.S. Cucumis melo PIs to Crown Rot Caused by Phytophthora capsici
Authors: Donahoo Ryan S. , Turechek William W. , Thies Judy A. , Kousik Chandrasekar S.
Published: February 2019

Phytophthora capsici is an aggressive pathogen that is distributed worldwide with a broad host range infecting solanaceous, fabaceous, and cucurbitaceous crops. Over the past two decades, increased incidence of Phytophthora blight, particularly in eastern states, has threatened production of many vegetable crops. Cucumis melo L. (honeydew and muskmelon), although especially susceptible to fruit rot, is also highly susceptible to crown rot. Currently, little is known about host resistance to P. capsici in C. melo. To assess crown rot resistance in C. melo seedlings, 308 U.S. PIs, and two commercial cultivars (Athena and Dinero) were grown under greenhouse conditions. Seedlings with three to four true leaves were inoculated with a five-isolate zoospore suspension (1 × 104 zoospores per seedling) at the crown and monitored for 6 weeks. All the susceptible control plants of Athena died within 7 days post-inoculation. The majority of the PIs (281 of 308) were highly susceptible to crown rot and succumbed to the disease rapidly and had less than 20% of the plants survive. Several PIs (PI 181748, PI 182964, and PI 273438) succumbed to crown rot earlier than the susceptible melon cultivars. Eighty-seven PIs selected on the basis of the first screen were re-evaluated and of these PIs, 44 were less susceptible than cultivars Athena and Dinero. Twenty-five of the 87 PIs were evaluated again and of these six PI, greater than 80% of the plants survived in the two evaluations. Disease development was significantly slower on these PIs compared with the susceptible checks. High levels of resistance in S1 plants of PI 420180, PI 176936, and PI 176940 were observed, which suggests that development of resistant germplasm for use in breeding programs can be accomplished. Further screening and careful selection within each of these PIs can provide a framework for the development of resistant germplasm for use in breeding programs.
Horticultural Research and Education Opportunities in Indonesia
Authors: Davis Tim D. , Hariyadi Purwiyatno
Published: February 2019

Indonesia is one of the most populated countries in the world and is rich in plant biodiversity. The country’s hot humid climate is conducive to the production of many tropical horticultural crops. There are many plant species indigenous to Indonesia that have potential as horticultural crops but which have not been fully evaluated and therefore remain underused. Many of these plants have market potential and may have value for human health and nutrition. Furthermore, horticulture has been identified as one of the priority areas for collaboration between U.S. and Indonesian universities and for Indonesian agricultural development. Accordingly, we are presently working with three Indonesian universities to facilitate agricultural development related to horticulture by: 1) strengthening their curriculum related to plant biodiversity; 2) conducting research aimed at identifying bioactive compounds in underused plants that may have benefit to human health; 3) establishing university-led outreach education programs that lead to a better understanding of plant biodiversity and use; and 4) fostering enterprise based on underused Indonesian plant species. Other untapped agricultural research and development opportunities exist in the postharvest handling of tropical fruits and vegetables. Overall, the climate for collaboration between U.S. and Indonesian academic institutions is quite favorable from both a political and a scientific perspective.
Development of New World Crops by Indigenous Americans
Authors: Janick Jules
Published: February 2019

Advanced agricultural and horticultural systems are a feature of pre-Columbian civilizations of the Americas. Practically all of the crops that originated in the New World were domesticated before European incursions. Thus, the New World crops currently grown in Asia, Africa, Europe, and Oceania should be considered as a contribution of indigenous cultures of the Americas to humanity. The history of these indigenous crops can be found in the written post-Columbian record of explorers, correspondents, travelers, and botanists. It can also be traced in the iconographic record derived from pre-Columbian artifacts, illustrated manuscripts, herbals, paintings, and sculpture. This information is particularly useful for such fields as taxonomy, genetics, crop domestication, crop evolution, and genetic diversity. Major New World crops to be reviewed include grains and pseudograins (amaranth, maize, quinoa), legumes (common bean, lima beans, peanut), cucurbits (chayote, pumpkins, squash), solanaceous fruits (capsicum peppers, husk tomato, pepino, tomato), starchy roots and tubers (cassava, potato, sweetpotato), fruit and nuts (blueberry, brambles, cactus pear, cashew, papaya, pineapple, strawberry), beverage crops (cacao, mate), ornamentals (dahlia, fuchsia, sunflower), and industrial crops (cotton, Pará rubber, tobacco).
Cuttings of Impatiens, Pelargonium, and Petunia Propagated under Light-emitting Diodes and High-pressure Sodium Lamps Have Comparable Growth, Morphology, Gas Exchange, and Post-transplant Performance
Authors: Currey Christopher J. , Lopez Roberto G.
Published: February 2019

Increasing photosynthetic daily light integral (DLI) by supplementing with high-pressure sodium (HPS) lamps during propagation has been shown to enhance photosynthesis and biomass accumulation of cuttings. The development of high-intensity light-emitting diodes (LEDs) is a promising technology with potential as a greenhouse supplemental lighting source. Our objective was to quantify the impact of narrow spectra supplemental lighting from LEDs on growth, morphology, and gas exchange of cuttings compared with traditional HPS supplemental lighting. Cuttings of Impatiens hawkeri W. Bull ‘Celebrette Frost’, Pelargonium ×hortorum L.H. Bailey ‘Designer Bright Red’, and Petunia ×hybrida Vilm. ‘Suncatcher Midnight Blue’ were received from a commercial propagator and propagated in a glass-glazed greenhouse at 23 °C air and substrate temperature set points. After callusing (≈5 mol·m−2·d−1 for 7 days), cuttings were placed under 70 μmol·m−2·s−1 delivered from HPS lamps or LED arrays with varying proportions (%) of red:blue light (100:0, 85:15, or 70:30). After 14 days under supplemental lighting treatments, growth, morphology, and gas exchange of rooted cuttings were measured. There were no significant differences among Impatiens and Pelargonium cuttings grown under different supplemental light sources. However, compared with cuttings propagated under HPS lamps, stem length of Petunia cuttings grown under 100:0 red:blue LEDs was 11% shorter, whereas leaf dry mass, root dry mass, root mass ratios, and root:shoot ratio of cuttings grown under 70:30 red:blue LEDs were 15%, 36%, 17%, and 24% higher, respectively. Supplemental light source had minimal impact on plants after transplant. Our data suggest that LEDs are suitable replacements for HPS lamps as supplemental light sources during cutting propagation.
Optimal Growing Substrate pH for Five Sedum Species
Authors: Zheng Youbin , Clark Mary Jane
Published: February 2019

To determine the optimal growing substrate pH values for Sedum plants, Sedum album, Sedum reflexum ‘Blue Spruce’, Sedum spurium ‘Dragon’s Blood’, Sedum hybridum ‘Immergrunchen’, and Sedum sexangulare were grown in containers using peatmoss and perlite-based substrates at five target pH levels (i.e., 4.5, 5.5, 6.5, 7.5, and 8.5). Optimal pH levels, calculated from dry weight regression models, were 6.32, 6.43, 5.71, 6.25, and 5.91 for S. album, S. reflexum, S. spurium, S. hybridum, and S. sexangulare, respectively, and 5.95 overall. Sedum spurium dry weight varied the most among pH treatments (i.e., 9.5 times greater at pH 6.3 vs. 8.3), whereas S. reflexum varied the least (i.e., 1.3 times greater at pH 6.3 vs. 4.4), indicating species-specific growth responses to growing substrate pH. These findings identified a narrow range of optimal growing substrate pH levels within a wider pH range tolerated by five Sedum spp. Therefore, by adjusting substrate pH to optimal levels, Sedum growth can be maximized.
Analytical Determination of the Lag Phase in Grapes by Remote Measurement of Trellis Tension
Authors: Tarara Julie M. , Chaves Bernardo , Sanchez Luis A. , Dokoozlian Nick K.
Published: February 2019

The lag phase (L) of grape berry growth is used to determine the timing of hand sampling for yield estimation. In commercial practice, growers apply scalars to measurements of berry of cluster masses under the assumption that fruit was assessed during L, which is the short period of slowest increase in fruit mass that occurs between the first and second sigmoid curves that describe growth in fleshy fruits. To estimate L, we used an automated remote system that indirectly detects increases in vegetative and fruit mass in grapevines by monitoring the tension (T) in the main load-bearing wire of the trellis. We fitted logistic curves to the change in T (ΔT) such that the parameters could be interpreted biologically, particularly the onset of L: the asymptotic deceleration of growth. Curves fit the data well [root mean square error (RMSE) 4.2 to 14.9] in three disparate years and two vineyards. The onset of L was most sensitive to the inflection point of the first logistic curve but relatively insensitive to its shape parameter. The analytical solution of the second derivative of the first logistic curve for its minimum predicted the apparent onset of L with a range of 3 to 5 days among replicates. The roots of the third derivative allowed analytical solutions for the onset of the first rapid growth phase and L, consistently predicting the onset of L 2 to 15 days earlier than was identified by trained observers who examined ΔT curves. Remote sensing of ΔT could better time field sampling and decrease current reliance on visual and tactile assessment to identify the onset of L, thus improving yield estimation in grapes.
Past, Present, and Future of Jujubes—Chinese Dates in the United States
Authors: Yao Shengrui
Published: February 2019

This article summarizes jujube importation and culture history and current jujube cultivars in the United States. Described within are jujube taxonomy, biology, adaptation, fruit nutrition, pests and diseases, propagation, and research conducted in the United States. It also discusses the current issues with jujubes in the United States and possible solutions to them. Jujube adapted and grew well in the southern and southwestern United States, and it could become a valuable industry in the United States within 15 to 20 years.
Variation among Highbush Blueberry Cultivars for Frost Tolerance of Open Flowers
Authors: Rowland Lisa J. , Ogden Elizabeth L. , Takeda Fumiomi , Glenn David Michael , Ehlenfeldt Mark K. , Vinyard Bryan T.
Published: February 2019

Injury of open flowers often occurs in fruit crops by late winter or early spring frosts and can result in significant reduction in yield. In this study, freezing tolerance of open flowers of five highbush blueberry cultivars, Bluecrop, Elliott, Hannah’s Choice, Murphy, and Weymouth, was determined using two freezing methods. Methods involved either placing whole plants in a radiation frost chamber or detached shoots in a glycol-freezing bath. In both methods, plants (or excised shoots) with opening flowers were exposed to temperatures ranging from –2 to –10 °C. After freeze treatments, several flower parts were evaluated for damage and the lethal temperature50 (LT50) determined. In order, from the most sensitive flower part to the least sensitive on average, were the corolla, filament, anther, style, exterior ovary, stigma, ovules, interior ovary, and placenta. A two-way analysis of variance (ANOVA) found no significant effect of the freezing method on the calculated freeze damage to most of the various flower parts. However, a significant genotype effect was found on freeze damage to the style, filament, anthers, and exterior ovary. Overall, ‘Bluecrop’ was the most sensitive to freezing, whereas ‘Hannah’s Choice’ and ‘Murphy’ were the most freezing-tolerant. In conclusion, genotypic variability in frost tolerance of open highbush blueberry flowers was detected, which can be exploited in breeding for more frost-tolerant cultivars.
Responses to Root-zone Water Content of Shrub Congeners from Eastern North America and Mediterranean California
Authors: Peterson Bryan J. , Graves William R.
Published: February 2019

Numerous genera of plants are distributed in both eastern North America and in portions of California with the dry summers of Mediterranean climates. We compared effects of flooding and drought on relative growth rate (RGR), photosynthesis, and biomass of seedlings of two genera, Sambucus L. and Ptelea L., with congeners in both regions. Ptelea crenulata Greene and Sambucus nigra ssp. cerulea (Raf.) R. Bolli from the San Francisco Bay area and Ptelea trifoliata L. and Sambucus nigra ssp. canadensis (L.) R. Bolli from mesic, deciduous forests in eastern North America were studied. Potted seedlings were subjected to six treatments, three extents of root-zone inundation and three severities of drought (irrigation when soil moisture by volume decreased to 5%, 10%, and 20%). After 5 weeks, deleterious effects of inundation were more pronounced among plants from the West than among their eastern congeners. For example, RGR of western and eastern Sambucus with completely inundated root zones was reduced 116% and 25%, respectively. All western and eastern Ptelea died when root zones were completely inundated, but inundating the lower half of the root zone killed all western plants but only reduced RGR among eastern plants. Photosynthesis of Sambucus from the West was lowest with complete inundation and was similar across the remaining treatments. In contrast, photosynthesis of eastern Sambucus was lowest during severe drought but otherwise similar. Photosynthesis of Ptelea was sensitive to both drought and flooding, and moderate root-zone water content led to the highest rates for both western and eastern plants. For both genera, maximal photosynthesis per unit leaf area was greater among western than eastern plants, but eastern plants had greater total leaf area and biomass. Root-to-shoot ratios of western Sambucus were greater than ratios of plants from the East after all treatments, whereas western Ptelea had greater root-to-shoot ratios than eastern Ptelea only under severe drought. Although comparative sensitivity to drought of plants from California and eastern North America varied in these genera, Mediterranean Sambucus and Ptelea both showed greater sensitivity to root-zone inundation than did their eastern congeners.
Pecan Orchard Renewal: Influence of Established Trees and Remaining Stumps on Transplant Growth and Crown Gall Infection
Authors: Smith Michael W. , Goff William D. , Wells M. Lenny
Published: February 2019

The productive life of a pecan [Carya illinoinensis (Wangenh.) K. Koch] orchard frequently spans two or more generations, but eventually orchards require renewal. Weather events damage tree canopies, pests affect tree health and productivity, and new cultivars offer greater yield potential or better nut quality. A popular method of orchard renewal is selective tree removal combined with interplanting new trees. Many old pecan orchards in the southeastern United States are infected with crown gall [Agrobacterium tumefaciens (Smith and Townsend) Conn.], potentially a problem for interplanted trees. Two tree types, nursery-grafted trees and seedling trees that were grafted 3 years after transplanting, were evaluated 6 years after transplanting. Transplanted trees varied in distances from established 80-year-old trees or residual stumps after tree removal. Ten trees near the study site, located 3.6 m from crown gall-infected stumps, were excavated to determine disease incidence. No crown gall was observed on any of the 87 trees in the study or the excavated trees. Trunk diameters of interplanted trees increased as distance from the nearest stump decreased and distance from the nearest established tree increased. Leaf elemental concentrations of the 6-year-old transplants were not related to observed growth differences. Conclusions include 1) stumps promoted rapid transplant growth; 2) crown gall infections of transplanted trees were unlikely even when crown gall symptoms were obvious on adjacent trees and stumps; and 3) transplant growth was suppressed by established trees.
Induced Variation in Tetraploid Rudbeckia subtomentosa ‘Henry Eilers’ Regenerated from Gamma-irradiated Callus
Authors: Oates Kelly M. , Touchell Darren H. , Ranney Thomas G.
Published: February 2019

Rudbeckia subtomentosa ‘Henry Eilers’ is an adaptable and popular garden plant; however, reduction in height and increased novelty in flower color would be desirable. The effect of gamma radiation dose on in vitro survival and development, and ex vitro fertility, phenology, and morphology of tetraploid Rudbeckia subtomentosa ‘Henry Eilers’ was investigated. In vitro embryogenic callus was treated with gamma radiation (0, 5, 10, 20, or 40 Gy). Rooted microshoots were established ex vitro and evaluated for morphology (plant height, number of flowers, diameter of the terminal flowers, diameter of the secondary flowers, number of stems, number of nodes, and internode length), date of first anthesis, winter survival, and pollen fertility on mature, second-year plants. Callus survival had no response to dose 2 months after treatment; however, microshoot number was significantly reduced with increasing dose. In vitro microshoot survival continued to decline at higher doses up to 4 months after treatment. Plant height, average stem height, number of flowers, flower diameter, percent winter survival, and pollen viability were all reduced with increasing radiation dose. Date of first anthesis was also delayed with increased radiation dose. Several off phenotypes were recorded including increased apical splitting of the ray florets in several plants. Gamma radiation was somewhat effective for reducing the height of R. subtomentosa ‘Henry Eilers,’ but flower morphology, flower number, and plant overwintering survival were often negatively affected with increasing radiation dose. Treating callus with low levels of gamma radiation (5–10 Gy) resulted in relatively high in vitro and field survival while inducing a range of other mutations that could be selected.
Regeneration of Plants from Fraxinus nigra Marsh. Hypocotyls
Authors: Beasley Rochelle R. , Pijut Paula M.
Published: February 2019

Fraxinus nigra Marsh. (black ash) is a native North American hardwood tree species that is ecologically important and has ethnobotanical significance to American Indian communities of the eastern United States. Black ash has immature embryos at seed set, combined with complex stratification requirements, making natural regeneration difficult. This, combined with the threat and devastation being caused by the emerald ash borer, makes an in vitro adventitious shoot regeneration and rooting protocol imperative for mass propagation, conservation, and genetic improvement of this species. Hypocotyls were cultured for 4 weeks on a modified Murashige and Skoog (MS) medium containing 13.3 μM 6-benzylaminopurine (BA) and 4.5 μM thidiazuron for adventitious shoot induction. Shoots continued to regenerate when explants were then cultured on MS medium supplemented with Gamborg B5 vitamins plus 0.2 g·L−1 glycine (B5G), 6.7 μM BA, 1 μM indole-3-butryic acid (IBA), and 0.29 μM gibberellic acid (GA3) for 4 weeks, followed by transfer to MSB5G medium with 13.3 μM BA, 1 μM IBA, and 0.29 μM GA3 for shoot elongation. Once elongated, the microshoots were continuously micropropagated through nodal sectioning, and cultured on MSB5G medium supplemented with 13.3 μM BA, 1 μM IBA, 0.29 μM GA3, and 0.2 g·L−1 casein hydrolysate. Rooting of elongated microshoots was successful using woody plant medium supplemented with 4.9 μM IBA and 5.7 μM indole-3-acetic acid with a 10-day initial dark culture for root induction followed by culture under a 16-h photoperiod. Rooted plantlets were successfully acclimatized to the greenhouse with 100% survival.
Plant Growth Stimulation and Root Colonization Potential of In Vivo versus In Vitro Arbuscular Mycorrhizal Inocula
Authors: Calvet Cinta , Camprubi Amelia , Pérez-Hernández Ana , Lovato Paulo Emilio
Published: February 2019

Inoculum of arbuscular mycorrhizal fungi, with growing use in horticulture, is produced mainly in two technically different cultivation systems: in vivo culture in symbiosis with living host plants or in vitro culture in which the fungus life cycle develops in association with transformed roots. To evaluate the effectiveness and the infectivity of a defined isolate obtained by both production methods, a replicated comparative evaluation experiment was designed using different propagules of Rhizophagus irregularis produced in vivo on leek plants or in vitro in monoxenic culture on transformed carrot roots. The size of the spores obtained under both cultivation methods was first assessed and bulk inoculum, spores, sievings, and mycorrhizal root fragments were used to inoculate leek plantlets. Spores produced in vitro were significantly smaller than those produced in vivo. Although all mycorrhizal propagules used as a source of inoculum were able to colonize plants, in all cases, leek plants inoculated with propagules obtained in vivo achieved significantly higher mycorrhizal colonization rates than plants inoculated with in vitro inocula. Inoculation with in vivo bulk inoculum and in vivo mycorrhizal root fragments were the only treatments increasing plant growth. These results indicate that the production system of arbuscular mycorrhizal fungi itself can have implications in the stimulation of plant growth and in experimental results.
Plant Growth, Fruit Yield and Quality, and Tolerance to Verticillium Wilt of Grafted Watermelon and Tomato in Field Production in the Pacific Northwest
Authors: Buller Sacha , Inglis Debra , Miles Carol
Published: February 2019

Growth, fruit yield and quality, and potential tolerance to verticillium wilt (Verticillium dahliae) were compared among non-grafted, self-grafted, and grafted triploid watermelon (Citrullus lanatus Thunb., ‘Crisp’n Sweet’) and heirloom tomato (Solanum lycopersicum, ‘Cherokee Purple’). Rootstocks for watermelon were ‘Emphasis’ bottle gourd (Lagenaria sicerarea) and ‘Strong Tosa’ interspecific squash hybrid (Cucurbita maxima × Cucurbita moschata), and rootstocks for tomato were ‘Beaufort’ and ‘Maxifort’ interspecific tomato (Solanum lycopersicum × Solanum habrochaites). Field trials were carried out in 2010 and 2011 at Hermiston and Eltopia (eastern Oregon and Washington, respectively) and Mount Vernon (western Washington). Grafted watermelon had significantly larger stem diameter than non-grafted and self-grafted plants both years at Mount Vernon, whereas there were no differences at Hermiston or Eltopia. Grafted tomato in 2011 had significantly larger stem diameter than non-grafted and self-grafted plants at Eltopia and Mount Vernon, and ‘Beaufort’-grafted plants were significantly taller than other treatments at Mount Vernon. Grafting did not impact watermelon or tomato fruit yield or quality at any location either year. Foliar symptoms of verticillium were not observed on ‘Crisp’n Sweet’ watermelon at the eastern locations either year; however, at Mount Vernon, ‘Emphasis’ and ‘Strong Tosa’-grafted plants had significantly lower verticillium wilt severity than non-grafted and self-grafted plants both years. Microsclerotia were observed in all recovered watermelon stems sampled at Eltopia and Mount Vernon. V. dahliae was isolated from non-grafted and ‘Emphasis’-grafted ‘Crisp’n Sweet’ stems at Eltopia and non-grafted, self-grafted, and ‘Strong Tosa’-grafted stems at Mount Vernon. Foliar symptoms of verticillium wilt and microsclerotia in stems were not observed on ‘Cherokee Purple’ plants at either location both years despite site histories of the disease. Grafting with ‘Emphasis’ and ‘Strong Tosa’ rootstocks may be an effective strategy for managing verticillium wilt on watermelon in western Washington; however, grafting ‘Cherokee Purple’ onto ‘Beaufort’ and ‘Maxifort’ did not provide any advantages for tomato under the field conditions of this study.
Crop and Soil Nitrogen Dynamics in Annual Strawberry Production in California
Authors: Bottoms Thomas G. , Hartz Timothy K. , Cahn Michael D. , Farrara Barry F.
Published: February 2019

The impact of strawberry production on nitrate contamination of groundwater is of major concern in the central coast region of California. Nitrogen (N) fertilization and irrigation management practices were monitored in a total of 26 fall-planted annual strawberry (Fragaria ×ananassa Duch.) fields in 2010 and 2011. Soil mineral N (SMN, top 30 cm depth) was determined monthly. Irrigation applied was monitored, and crop evapotranspiration (ETc) was estimated. Growers were surveyed regarding their N fertilization practices. Aboveground biomass N accumulation was estimated by monthly plant sampling in seven fields. The effect of preplant controlled-release fertilizer (CRF) rate on fruit yield was investigated in three fields. The growers’ CRF application rate (121 or 86 kg·ha−1 N as 18N–3.5P–10.8K, 7- to 9-month release rating) was compared with a half rate (all fields) and no CRF in one field. The rate of N release from this CRF product was evaluated using a buried bag technique. Median CRF N and total seasonal N application (CRF + in-season fertigation through drip irrigation) were 101 and 260 kg·ha−1, respectively, with total seasonal N application varying among fields from 141 to 485 kg·ha−1. Biomass N accumulation was slow through March (less than 25 kg·ha−1) and then increased by ≈1.1 kg·ha−1·d−1 from April through mid-September. Mean seasonal biomass N accumulation was estimated at 225 kg·ha−1 by 15 Sept. Approximately 70% of CRF N was released before 1 Apr. Biomass N accumulation between planting and April was much lower than the combined amount of CRF N release and SMN decline over that period, suggesting substantial winter N loss. Conversely, N loss during the summer harvest season (May through August) appeared limited in most fields. Median SMN was maintained below 10 mg·kg−1, and median irrigation was 113% of estimated ETc during this period. Reduction in CRF rate did not affect marketable fruit yield in two of three trials; an 8% yield reduction was observed in the remaining trial when the CRF rate was reduced, but the decline may have been affected by spring irrigation and fertigation practices.
Developmental Response of St. Augustinegrass Cultivars and Experimental Lines in Moderate and Heavy Shade
Authors: Wherley Ben , Chandra Ambika , Genovesi Anthony , Kearns Mason , Pepper Tim , Thomas Jim
Published: February 2019

St. augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] is considered to be one of the most shade-tolerant warm-season turfgrasses, yet information is lacking on intraspecies developmental responses and performance in shade. This greenhouse study was conducted to 1) compare quality, development, and physiological responses of 10 commercial and experimental lines of st. augustinegrass in moderate and heavy [32% and 15% photosynthetic photon flux (PPF), respectively] shade environments’ and 2) evaluate physiological and morphological indicators that could be used in rapid screening for shade tolerance among st. augustinegrass progeny from a segregating population. A range of shade tolerance was observed between the entries, as noted by quality and percent green cover after 10 weeks of imposed shade conditions. In moderate shade, most entries maintained acceptable (6 or greater) quality and greater than 50% green cover. However, in heavy shade, only ‘Captiva’, ‘Amerishade’, and ‘PI 600734’ maintained acceptable quality, with only PI 600734 and Captiva maintaining greater than 50% cover. ‘TAES 5732-6’, an embryo rescue-derived hybrid from ‘Floratam’, exhibited the least shade tolerance of the group in both shade environments. Neither chlorophyll content nor total nonstructural carbohydrates related well to observed shade quality differences between the entries. A strong correlation existed between shoot elongation rate of a cultivar and its corresponding final percent green cover in moderate shade (R2 = 0.66) but not in heavy shade (R2 = 0.19), suggesting that moderate shade may be the better environment for discriminating genetic differences among st. augustinegrass germplasm for shade tolerance.
Observation of the Disomic Inheritance of Four Allelic Pairs in the Octoploid Cultivated Strawberry
Authors: Honjo Masanori , Yui Susumu , Kunihisa Miyuki
Published: February 2019

Although recent genetic studies suggest that octoploid cultivated strawberry, Fragaria ×ananassa Duch., is highly diploidized, there have been no reports that directly and clearly described the behavior of four allelic pairs. In this study, we demonstrated the disomic inheritance of four allelic pairs in F. ×ananassa by using two highly polymorphic simple sequence repeat markers. By genotyping the offspring of ‘Summer-princess’ (containing eight distinct alleles of marker FxaHGA02P13) × ‘Dekoruju’ (containing another four distinct alleles for this marker), four allelic pairs could be identified in ‘Summer-princess’. In a similar way, four allelic pairs could be identified for cultivar Ohishi-shikinari and marker EMFvi136. The results of this study provide direct evidence that at least part of the octoploid strawberry genome is fully diploidized and that the genome composition hypothesis AAA′A′BBB′B′ is possible as suggested by other recent genetic studies.
Chlorophyll Fluorescence Sorting Method to Improve Quality of Capsicum Pepper Seed Lots Produced from Different Maturity Fruits
Authors: Kenanoglu Burcu Begüm , Demir Ibrahim , Jalink Henk
Published: February 2019

This work was conducted to investigate the efficacy of chlorophyll fluorescence (CF) sorting to improve seed germination, seedling emergence, and vigor of seeds produced from different maturity fruits of four different cultivars. Four harvest dates from each cultivar were evaluated by harvesting orange (immature), bright red (half-mature), dark red (mature), and dark red and soft (overmature) fruits. Seeds were either sorted or nonsorted after harvesting and standard laboratory germination, seedling emergence, and controlled deterioration tests were conducted. CF sorting significantly increased laboratory germination, seedling emergence, and seed vigor. Maximum improvements were obtained from seeds harvested from half-mature and mature stages. Mean germination improvement among cultivars between CF-sorted and nonsorted seeds were 14% in the immature seeds, 11% in half-mature seeds, 6% in mature seeds, and 9% in overmature seeds. Improvements in seedling emergence were 21%, 17%, 9%, and 10% and 4%, 11%, 10%, 14% for seed vigor (CD germination) in the all maturity stages of seed lots, respectively. CF has the potential to upgrade seed quality in pepper lots as a non-destructive sorting technology.
Leaf Shape, Growth, and Antioxidant Phenolic Compounds of Two Lettuce Cultivars Grown under Various Combinations of Blue and Red Light-emitting Diodes
Authors: Son Ki-Ho , Oh Myung-Min
Published: February 2019

Light-emitting diodes (LEDs) of short wavelength ranges are being developed as light sources in closed-type plant production systems. Among the various wavelengths, red and blue lights are known to be effective for enhancing plant photosynthesis. In this study, we determined the effects of blue and red LED ratios on leaf shape, plant growth, and the accumulation of antioxidant phenolic compounds of a red leaf lettuce (Lactuca sativa L. ‘Sunmang’) and a green leaf lettuce (Lactuca sativa L. ‘Grand Rapid TBR’). Lettuce seedlings grown under normal growth conditions (20 °C, fluorescent lamp + high-pressure sodium lamp 177 ± 5 μmol·m−2·s−1, 12-hour photoperiod) for 18 days were transferred into growth chambers that were set at 20 °C and equipped with various combinations of blue (456 nm) and red (655 nm) LEDs [blue:red = 0:100 (0 B), 13:87 (13 B), 26:74 (26 B), 35:65 (35 B), 47:53 (47 B) or 59:41 (59 B)] under the same light intensity and photoperiod (171 ± 7 μmol·m−2·s−1, 12-hour photoperiod). Leaf width, leaf length, leaf area, fresh and dry weights of shoots and roots, chlorophyll content (SPAD value), total phenolic concentration, total flavonoid concentration, and antioxidant capacity were measured at 2 and 4 weeks after the onset of LED treatment. The leaf shape indices (leaf length/leaf width) of the two lettuce cultivars subjected to blue LEDs treatment were similar to the control, regardless of the blue-to-red ratio during the entire growth stage. However, 0 B (100% red LED) induced a significantly higher leaf shape index, which represents elongated leaf shape, compared with the other treatments. Increasing blue LED levels negatively affected lettuce growth. Most growth characteristics (such as the fresh and dry weights of shoots and leaf area) were highest under 0 B for both cultivars compared with all other LED treatments. For red and green leaf lettuce cultivar plants, shoot fresh weight under 0 B was 4.3 and 4.1 times higher compared with that under 59 B after 4 weeks of LED treatment, respectively. In contrast, the accumulation of chlorophyll, phenolics (including flavonoids), and antioxidants in both red and green leaf lettuce showed an opposite trend compared with that observed for growth. The SPAD value (chlorophyll content), total phenolic concentration, total flavonoid concentration, and antioxidant capacity of lettuces grown under high ratios of blue LED (such as 59 B, 47 B, and 35 B) were significantly higher compared with 0 B or control conditions. Thus, this study indicates that the ratio of blue to red LEDs is important for the morphology, growth, and phenolic compounds with antioxidant properties in the two lettuce cultivars tested.
Iron-induced Nickel Deficiency in Pecan
Authors: Wood Bruce W.
Published: February 2019

Economic loss resulting from nickel (Ni) deficiency can occur in horticultural and agronomic crops. This study assesses whether excessive iron (Fe) can induce Ni deficiency. Both chelated Fe and diethylenetriaminepentaacetic acid (DPTA; a commonly used Fe-chelant) induces Ni deficiency in pecan [Carya illinoinensis (Wangenh.) K. Koch]. Foliar sprays of Fe [Fe-DPTA (1.1995 g·L−1)] during early post-budbreak shoot growth can trigger, or increase in severity, Ni deficiency symptoms in the emerging pecan canopy. Deficiency is also inducible in greenhouse-grown ‘Desirable’ seedlings at budbreak by Fe-DPTA application to soil and to a much lesser extent by DPTA alone. Endogenous Fe, just after budbreak, triggers Ni deficiency-associated distortions in pecan seedling leaf growth and morphology when the Fe:Ni is ≈150 or greater with subsequent severity being proportional to the Fe:Ni ratio and Fe:Ni ≈1200 or greater triggering extreme dwarfing of canopy organs. Timely treatment of symptomatic organs with foliar-applied Ni-sulfate restores normal growth, whereas foliar treatment with salts of other transition metals (titanium, vanadium, chromium, cobalt, copper, zinc, and molybdenum) of possible metabolic significance is ineffective. Results indicate that excessive endogenous Fe, and DPTA to a lesser extent, in organs and tissues during early post-budbreak growth can trigger Ni deficiency. A similar Fe on Ni antagonism may also occur with the Ni-associated nutritional physiology of other crops; thus, excessive exposure to chelated Fe not only triggers Ni deficiency in pecan, but may also occur in other horticultural and agronomic crops.
Nitric Oxide Alleviates the Inhibition of Salinity Stress on Seed Germination and Seedling Growth of Cynanchum bungei Decne (Asclepiadaceae)
Authors: Zhang Haiyan
Published: February 2019

As a rare, endemic, important, and salt-sensitive medicinal plant species in China, Cynanchum bungei Decne seeds were treated to germinate with distilled water (control) or NaCl solutions in the presence or absence of nitric oxide (NO) donor sodium nitroprusside (SNP) to investigate the effects of exogenous NO on seed germination, seedling growth, and antioxidant enzyme activities under salt stress. Sixty mm NaCl significantly inhibited the germination and seedling growth of C. bungei. Exogenous SNP alleviated salt stress in a dose-dependent manner, as indicated by accelerating the seed germination, increasing germination index (GI), vigor index (VI), germination velocity (GV), shoot height (SH), taproot length (TL), shoot biomass (SB), root biomass (RB) as well as shortening mean germination time (MGT), and 0.1 mm SNP was the optimal concentration. SNP at 0.1 mm greatly increased the activities of superoxide dismutase (SOD) and catalase (CAT) under salt stress, which contributed to alleviate the oxidative stress induced by salt stress in C. bungei seeds. It is concluded that NO treatment is an effective practice to improve C. bungei seed germination under saline condition.
Luther Burbank’s Contributions to Walnuts
Authors: Preece John E. , McGranahan Gale
Published: February 2019

Luther Burbank began making controlled crosses between walnut species in the late 19th century after hearing about a “supposed natural European hybrid walnut.” He crossed Juglans hindsii (northern California black walnut) × J. regia (Persian walnut) and produced progeny that he named ‘Paradox’ because of its extremely fast growth and other “anomalies.” He also crossed two American species, J. hindsii × J. nigra (eastern black walnut), producing ‘Royal’ walnut progeny that were fast-growing and prolific nut producers. A third interspecific hybrid was a cross between J. ailantifolia (Japanese walnut) × J. regia that resulted in extremely vigorous progeny but was not named. He observed segregation in the F2 populations and described giants and dwarfs as reversions to ancestral forms. Luther Burbank also made selections for walnut scion cultivars and was especially interested in thin-shelled nuts. He collected seeds from a J. regia growing in San Francisco because it produced regularly and had very high-quality nuts with relatively thin but poorly sealed shells. He selected one of its seedlings as ‘Santa Rosa Soft-Shell’ and described it as bearing large crops of nuts that were nearly white with thin shells and delicious white meat. Burbank’s contributions to the walnut industry endure to this day, especially through the widespread use of seedling and clonal ‘Paradox’ walnut rootstocks.
Rising Plate Meter Calibrations for Forage Mass of Wheat and Rye
Authors: Cho Whoi , Brorsen B. Wade , Biermacher Jon T. , Rogers James K.
Published: February 2019

Core Ideas

The rising plate meter was useful in predicting forage mass.

A quadratic functional form is favored for predicting forage mass using the rising plate meter.

Relationships differed by species, season, and tillage

Estimating forage availability is important in optimizing livestock stocking rates. The rising plate meter was developed to estimate forage availability. It needs a calibration equation to convert its measurement to a prediction of forage mass, and predictions can vary across crops, seasons, and locations. Our research objective was to derive new calibration equations for wheat (Triticum aestivum L.) and rye (Secale cereale L.). Most past literature used a linear model, but recent literature has suggested that using a quadratic model without an intercept could improve predictions. A non‐nested test was used to test among these two non‐nested models for wheat and rye calibration equations. The results favored the more encompassing model of a quadratic with an intercept; however, with wheat the quadratic with no intercept was not rejected. A pooling test indicated different equations were needed for species, seasonality (winter and non‐winter), and tillage type (tilled or no‐till).
Ta’wil: in Practices of Light
Authors: Mirza Narjis
Published: February 2019

This research is situated within an Islamic philosophical paradigm, with a series of experiments in studio art practice. In my investigation of Mulla Sadrā’s theory of systematic intensification, I was led towards Ta’wil, a unique method of interpretation, that is primarily used for interpreting the verses of the Quran. I extract this traditional Quranic method of interpretation, Ta’wil and translate it into a visual and collective dialogue, for a practice-oriented research. Keeping in view the traditional association of the method of Ta’wil towards the Quran, I suggest there is evidence that Ta’wil is a method that can be practised outside the interpretation of the text. It is a unique method of interpretation that performs in both physical and metaphysical worlds. Ta’wil is both a noun, as an object or happening in the physical, and a process of carrying a perceptible image (for example text of the Quran) towards higher and deeper understandings. I start my writing with a brief overview of my research area, moving towards Ta’wil in creative art practice.