bluuebunny/crossref_metadata_2025 huggingface dataset:
Localizing Starch Reserves in Mandevilla sanderi (Hemsl.) Woodson Using a Combined Histochemical and Biochemical Approach
Authors: Boutebtoub Wahiba , Chevalier Michel , Mauget Jean-Claude , Sigogne Monique , Morel Philippe , Galopin Gilles
Published: February 2019

Mandevilla sanderi is a plant of tropical origin of great horticultural interest because of its abundant flowering and its persistent foliage. Vegetative propagation requires the removal of leafy branches on the mother plant to produce cuttings. This loss of biomass must be compensated for by the growth of new branches thanks to the mobilization of reserves within the plant. Lack of knowledge about the physiology of this species therefore makes it necessary to characterize its different organs both at the level of their anatomic organization as well as at the level of their ability to store starch. After histological characterization of the different organs (leaves, stems, and roots), starch reserves were localized by histochemical analysis and quantified by biochemical analysis. Starch grains are mainly found in the parenchymatous cortex, the parenchymatous pith and xylem parenchyma cells, in tuberous roots and stems, and in the palisade and spongy mesophyll of leaves. In 22-week-old plants, the greatest quantity of starch is found in the leaves, whereas the tuberous roots have the highest concentration. The histological description of the different organs of Mandevilla sanderi and the localization of starch reserves allow us to assess the potential role of the different organs in plant growth and development. In the particular case of mother plant management, it is hoped that this knowledge will make it possible to optimize conditions for removing leafy branches.
Crop Load Overwhelms Effects of Gibberellic Acid and Ethephon on Floral Initiation in Apple
Authors: Schmidt Tory , Elfving Don C. , McFerson James R. , Whiting Matthew D.
Published: February 2019

Potential strategies against biennial bearing in apple [Malus × sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] include promotion of return bloom with an “on”-year application of ethephon or inhibition of return bloom with an “off”-year application of gibberellic acid (GA), but the influence of initial crop load on the efficacy of these bioregulators is poorly understood. In 2004 and 2005, six total trials were initiated in which whole trees were manually adjusted shortly before anthesis to one of three levels of crop load (100%, 50%, 0%) in ‘Cameo’, ‘Honeycrisp’, and ‘Fuji’; GA4 + 7 was overlaid on trees of each crop level in four trials and ethephon in two. In all trials, initial crop load was the primary determinant of return bloom; proportional influence on flower density, fruit density, and yield was generally most pronounced at the 50% crop level. GA4 + 7 consistently reduced floral initiation, whereas ethephon promoted it. Flowering responses from a historically alternating ‘Cameo’ trial site showed greater sensitivity to ethephon and less sensitivity to GA4 + 7 than did responses from parallel trials established in an annually bearing ‘Cameo’ block, suggesting a predilection of nascent buds to a specific fate before the influence of exogenous bioregulators or gibberellins from seeds produced in developing fruit. Light crop loads and GA4 + 7 applications generally promoted shoot extension, whereas heavy crops and ethephon had the opposite effect.
Differential Susceptibility of Prunus Germplasm (Subgenus Amygdalus) to a California Isolate of Xylella fastidiosa
Authors: Ledbetter Craig A. , Rogers Elizabeth E.
Published: February 2019

Seedling peach (Prunus persica Batsch) and clonal peach–almond hybrids are popular rootstock choices for commercial almond growers in California. In this study, clonal replicates of peach and almond [P. dulcis (Mill.) D.A. Webb] rootstock germplasm and a first-generation peach–almond hybrid created from them were challenged with Xylella fastidiosa isolate M23. Clonal replicates were needle-inoculated with M23 and maintained in a greenhouse environment for a growing season. Typical almond leaf scorch disease symptoms began to develop on M23-inoculated almonds 11 weeks after inoculation. No leaf scorch symptoms were observed on M23-inoculated peach or peach–almond hybrids. Quantitative real-time polymerase chain reaction revealed consistent levels of X. fastidiosa DNA among inoculated almond replicates, whereas X. fastidiosa DNA was undetectable in replicates of peach–almond hybrids. A trace level of X. fastidiosa DNA was detected in a single peach replicate, and statistical analysis demonstrated that this level differed significantly (P < 0.001) from that detected in almond replicates. Selected almonds were further sampled sequentially along their meristematic axes to examine bacterial titer throughout the trees. Selected almond trees differed significantly (P = 0.036) in bacterial titer, but no significant differences were noted in levels of X. fastidiosa from different vertical sections of the main growth axes. The results suggest that peach and peach–almond hybrid rootstock germplasm used by commercial almond tree nurseries in California are not primary inoculum sources for X. fastidiosa-induced diseases.
Host Status of Three Transgenic Plum Lines to Mesocriconema xenoplax
Authors: Nyczepir Andrew P. , Nagel Alexis K. , Schnabel Guido
Published: February 2019

The expression of gastrodianin antifungal protein (GAFP) in a form of its VNF isoform increases tolerance to Phytophthora root rot (Phytophthora cinnamomi) and the root-knot nematode (Meloidogyne incognita) in transgenic plum lines. However, nothing is known about the potential of the GAFP lectin to confer disease resistance to the ring nematode, Mesocriconema xenoplax, in plum. Three transgenic plum lines (4I, 4J, and 5D) expressing gafp-1 under the control of CaMV 35S promoter sequence were evaluated for their response to M. xenoplax in the greenhouse. All plum lines were rated as hosts of M. xenoplax. Among the individual plum lines tested, the number of M. xenoplax per gram of dry roots was lowest in the rhizosphere of transgenic line 5D, intermediate in that of the nontransformed control line, and greatest in line 4J. The results of this study indicate that the comparisons of the final soil densities (Pf) of adult and juvenile M. xenoplax expressed as nematodes per gram of dry roots provide a better measure of the nematode carrying capacity by the tested lines than Pf values referred to as number of M. xenoplax/100 cm3 soil.
Uncoupling the Sensory Effects of 1-Methylcyclopropene and Ripening Stage on ‘Hayward’ Kiwifruit
Authors: Almeida Domingos P.F. , Gomes Maria Helena
Published: February 2019

‘Hayward’ kiwifruit were treated with 0.5 μL·L−1 of 1-methylcyclopropene (1-MCP) and stored in air at 0 °C. Treatment with 1-MCP reduced softening of kiwifruit during storage but did not affect soluble solids or titratable acidity. Sensory analyses were performed by a consumer panel and by trained panelists after 41, 77, and 161 days in storage. 1-MCP treatment negatively affected consumer preference, expressed as degree of liking. The trained panel clearly perceived 1-MCP-treated kiwifruit after 41 days in storage at 0 °C as more sour and firmer but less juicy, less sweet, and less flavorful than untreated fruit. After 161 days in storage, the perceived differences between 1-MCP-treated and untreated fruit had been reduced for sweetness and acidity, but the panel perceived 1-MCP-treated fruit as firmer and lagging behind in the ripening process. Altering the poststorage ripening rate, by placing 1-MCP-treated fruit at a higher temperature than untreated controls, allowed fruit to develop in such a way that a sensory panel was unable to distinguish between treatments. This result indicates that 1-MCP-treated fruit can be perceived by the consumer as similar to untreated fruit if adequately conditioned.
Differential Uptake, Distribution within Tissues, and Use Efficiency of Manganese, Iron, and Zinc by Olive Cultivars Kothreiki and Koroneiki
Authors: Chatzistathis Theocharis , Therios Ioannis , Alifragis Dimitrios
Published: February 2019

Three-month-old rooted olive cuttings (Olea europaea L., cvs. Koroneiki and Kothreiki of ≈20 to 25 cm in height) were grown outdoors for 140 days (from 30 May until 17 Oct.) under ambient conditions in black plastic bags containing 3 kg of soil. Three soils from different parent material (Marl, Gneiss schist., and Peridotite) and with different physicochemical properties were chosen. In all the soils, ‘Kothreiki’ produced significantly greater total plant biomass compared with ‘Koroneiki’. Furthermore, between the two cultivars studied, ‘Kothreiki’ absorbed significantly greater quantity of manganese (Mn), iron (Fe), and zinc (Zn) per plant compared with ‘Koroneiki’. In all the soils, significantly greater concentrations of Mn, Fe, and Zn were recorded in the root system of both cultivars compared with those of leaves and stems. Between the two cultivars studied, ‘Kothreiki’ had greater percentage of the total Mn content distributed in the root system (74% to 80%) than ‘Koroneiki’ (44% to 56%). That high ability of ‘Kothreiki’ to accumulate Mn in its root system could possibly be advantageous in soils with high Mn concentrations and could constitute a detoxification mechanism to olive trees, protecting the above-ground part of the tree from Mn toxicity. Furthermore, greater concentrations of magnesium (Mg) were recorded in the root system of the olive plants than in leaves and stems, whereas potassium (K) and calcium (Ca) concentrations were greater in leaves compared with those of other tissues (roots and stems). The total per plant quantity of Ca, Mg, and K was significantly greater in the cultivar Kothreiki than ‘Koroneiki’ in all the soils tested. On the other hand, ‘Kothreiki’ presented significantly lower use efficiency of Mn in Marl and Gneiss schist soils, and that of Fe and Mg in all soils, so ‘Koroneiki’ could be considered as a Mn- and Fe-efficient olive cultivar, whereas ‘Kothreiki’ was Mn- and Fe-inefficient.
Performance of a Trichoderma harzianum Bentonite–vermiculite Formulation Against Fusarium Wilt in Seedling Nursery Melon Plants
Authors: Martínez-Medina Ainhoa , Roldán Antonio , Pascual Jose A.
Published: February 2019

Practical use of Trichoderma harzianum requires feasible formulated products. The objective of this study was to investigate the survival and effectiveness of a T. harzianum bentonite–vermiculite formulation against fusarium wilt and its growth-promotion effect on melon plants under nursery conditions compared with the incorporation of this agent as a nonformulated conidia suspension. The effectiveness of the application of T. harzianum to melon plants was related directly to its formulation, as the formulation had a clear influence on its survival on peat. The formulated form maintained the inoculation level of T. harzianum colony-forming units after 8 weeks, whereas the nonformulated form reduced it by two orders of magnitude. Plants treated with the bentonite–vermiculite formulation showed a higher shoot weight and higher resistance to fusarium wilt disease.
Isolation and Characterization of Twenty-four Microsatellite Loci for Rhododendron decorum Franch. (Ericaceae)
Authors: Wang Xue-qin , Huang Yuan , Long Chun-lin
Published: February 2019

Rhododendron decorum is a common species in southwest China and northeast Myanmar, in which the flowers have been eaten as a favorite vegetable. We isolated and characterized 24 microsatellite primer pairs from this species. The number of alleles ranged from two to seven. The observed and expected heterozygosities (HO and HE) were 0.3830 to 0.7855 and 0 to 0.7917, respectively. Eleven loci were significantly deviated from Hardy-Weinberg equilibrium as a result of the heterozygote deficiency. Cross-species amplification in another eight Rhododendron species showed their potential use for evolutionary and conservation studied in this genus. These markers will be useful to reveal the genetic population structure and genetic diversity of R. decorum.
Isolation and Characterization of Microsatellite Markers in the Endangered Species Taxus wallichiana Using the FIASCO Method
Authors: Yang Jun-Bo , Li Hong-Tao , Li De-Zhu , Liu Jie , Gao Lian-Ming , Li De-Zhu , Gao Lian-Ming , Liu Jie
Published: February 2019

The Himalayan yew, Taxus wallichiana Zucc., is an endangered species with a scatted distribution in the Eastern Himalayas and southwestern China. In the present study, 10 microsatellite markers from the genome of T. wallichiana were developed using the protocol of fast isolation by amplified fragment length polymorphism of sequences containing repeats (FIASCO). Polymorphism of each locus was assessed in 28 samples from four wild populations of the Himalayan yew. The allele number of the microsatellites ranged from two to five with an average of 2.9 per allele. The observed and expected heterozygosity varied from 0.00 to 1.00 and from 0.3818 to 0.7552, respectively. Cross-species amplification in another two yew species showed eight of them holding promise for sister species. Two of the 10 loci (TG126 and TC49) significantly deviated from Hardy-Weinberg expectations. No significant linkage disequilibrium was detected between the comparisons of these loci. These polymorphic microsatellite markers would be useful tools for population genetics studies and assessing genetic variations to establish conservation strategy of this endangered species.
Transpiration and Normalized Difference Vegetation Index Response of Seashore Paspalum to Soil Drying
Authors: Johnson Georgene L. , Sinclair Thomas R. , Kenworthy Kevin
Published: February 2019

A consistent response has been observed among many plant species in their leaf gas exchange as soils are subjected to a drying cycle; except for one case, these studies have not included turfgrass species. The current study reports the change in transpiration rate of six genotypes of seashore paspalum (Paspalum vaginatum Swartz) during soil drying when grown on either an organic soil or sand. On organic soil, the response was consistent with results with other plant species in that there was no decline in transpiration rate until the fraction of transpirable soil water (FTSW) reached the range of 0.25 to 0.31. The decline in transpiration rate when plants were grown on sand occurred in the FTSW range of 0.10 to 0.17, which was also consistent with reports for other species when grown on sand. The lower FTSW for the decline in transpiration rate on sand appears to be a result of the greater retention of water in fully wetted sand in pot experiments as compared with field conditions. Because the decline in transpiration occurred at a higher FTSW in ‘SeaIsle Supreme’, ‘Aloha’, and ‘SeaIsle 1’ than in ‘SeaIsle 2000’, this is an indication that these genotypes are water-conserving and may be better suited to water-deficit conditions. Quality changes in these grasses were monitored daily during the drying cycle by reflectance measurements of their normalized difference vegetation index (NDVI). No change in NDVI was observed for grasses grown on either soil type until the soil had become very dry and transpiration had decreased to low rates.
Evaluation of Alternative Turfgrass Species for Low-input Golf Course Fairways
Authors: Watkins Eric , Hollman Andrew B. , Horgan Brian P.
Published: February 2019

As restrictions on water use, fertilization, and pesticide applications continue to increase, golf course superintendents will need to use grass species that require reduced inputs. The objective of this study was to evaluate alternative turfgrass species under low-input fairways conditions. In 2005, 17 species were established on native soil in St. Paul, MN. Each species was evaluated at three levels of traffic (zero, three, or six passes per week using a drum-type traffic simulator) and two mowing heights (1.90 and 2.54 cm). Data collected included turfgrass quality and percent living stand density. In 2006, velvet bentgrass (Agrostis canina L.), colonial bentgrass (Agrostis capillaris L.), and creeping bentgrass (Agrostis stolonifera L.) maintained acceptable quality in all treatment combinations. In 2007, Chewings fescue (Festuca rubra L. ssp. fallax) and sheep fescue (Festuca ovina L.) were the top-performing species regardless of treatment. Hard fescue (Festuca brevipila Tracey) performed poorly in Year 1 and well in Year 2. All other species did not perform at an acceptable level during the study. The results of this study indicate that sheep fescue, Chewings fescue, colonial bentgrass, and velvet bentgrass should be studied further for use on low-input golf course fairways in the northern United States.
Responses of Creeping Bentgrass to Trinexapac-ethyl and Biostimulants under Summer Stress
Authors: Xu Yan , Huang Bingru
Published: February 2019

Summer decline in turf quality and growth of cool-season grass species is a major concern in turfgrass management. The objectives of this study were to investigate whether foliar application of trinexapac-ethyl (TE) and two biostimulants (TurfVigor and CPR) containing seaweed extracts would alleviate the decline in creeping bentgrass (Agrostis stolonifera L.) growth during summer months and to examine effects of TE and the biostimulants on leaf senescence and root growth. The study was performed on a ‘Penncross’ putting green built on a sandy loam soil at Hort Farm II, North Brunswick, NJ, in 2007 and 2008. Turf was foliar-sprayed with water (control), TE (0.05 kg a.i./ha), TurfVigor (47.75 L·ha−1), or CPR (19.10 L·ha−1) from late June to early September in a 2-week interval in both years. Turf quality, density, chlorophyll content, canopy photosynthetic rate (Pn), and root growth exhibited significant decline during July and August in both 2007 and 2008, to a greater extent in each parameter for the control treatment. Foliar application of TE resulted in significant improvement in turf quality, density, chlorophyll content, and Pn on certain sampling dates from July to September in both years compared with the control. Both TurfVigor and CPR significantly improved visual quality during July and August in both years by promoting both shoot and root growth. This study suggests that proper application of TE and selected biostimulants could be effective to improve summer performance of creeping bentgrass.
Powdery Mildew Resistance in the Peach Cultivar Pamirskij 5 Is Genetically Linked with the Gr Gene for Leaf Color
Authors: Pascal Thierry , Pfeiffer Fred , Kervella Jocelyne
Published: February 2019

Peach powdery mildew (Podosphaera pannosa var. persicae) is a major disease of peach trees [Prunus persica (L.) Batsch]. Various studies on powdery mildew resistance have been conducted in peach. The present study was initiated to determine the inheritance of powdery mildew resistance found in the green leaf peach rootstock ‘Pamirskij 5’. Crosses were carried out between ‘Pamirskij 5’ and the susceptible red leaf peach rootstock ‘Rubira’®. Segregation analysis performed in F1 (1:0), F2 (3:1), and test cross (1:1) progenies indicated single dominant gene control of peach powdery mildew resistance in ‘Pamirskij 5’. Cosegregation analysis provided clear evidence that the loci for powdery mildew resistance and the leaf color trait are very closely linked in ‘Pamirskij 5’. The estimated distance between these loci was 0 ± 3.26 cM for the F2 and 0 ± 0.00 cM for the test cross populations.
Induction of Tetraploidy to Feverfew (Tanacetum parthenium Schulz-Bip.): Morphological, Physiological, Cytological, and Phytochemical Changes
Authors: Majdi Mohammad , Karimzadeh Ghasem , Malboobi Mohammad A. , Omidbaigi Reza , Mirzaghaderi Ghader
Published: February 2019

An efficient colchicine-mediated chromosome doubling of diploid feverfew followed by the morphophenological, physiological, phytochemical, and cytological changes of the obtained tetraploid plants was conducted. One-week-old seedlings of feverfew were treated with 0.05% (w/v) colchicine for 2, 4, 6, 8, and 24 h. Tetraploid plants were regenerated after 4 months, showing significant changes in stomatal size and density; sizes of seed; flower, pollen, leaf, trichome, cell, nucleus, and parthenolide content; chromosome number; ploidy level; chlorophyll content index; and quantum efficiency of photosystem II. Such characteristics of induced tetraploid feverfews can be useful in medicinal and ornamental applications, e.g., the study of flower morphogenesis, trichome differentiation, and parthenolide biosynthesis. The increase in parthenolide in tetraploids of the next generation (selfed T0 plants) showed that ploidy induction is a good breeding method for feverfew.
Ripening and Physiological Changes in the Fruit of Persea schiedeana Nees during the Postharvest Period
Authors: Del Angel-Coronel Oscar Andrés , Cruz-Castillo Juan Guillermo , De La Cruz-Medina Javier , Famiani Franco
Published: February 2019

In terms of color, firmness, respiration, and ethylene production during the postharvest period, ripening is here characterized for the first time in the fruit of Persea schiedeana Nees. The results show a respiratory peak (respiratory climacteric) and an ethylene production peak, indicating that the fruit of P. schiedeana can be classified as climacteric. The fruit ripened rapidly, and senescence effects appeared 5 days after harvest. Together with appreciable weight loss during the postharvest period, this makes the fruit very perishable. Preliminary values for quantitative ripening indices are provided (fruit firmness, color lightness, hue angle, and chroma).
Sweet Cherry Cultivars Vary in Their Susceptibility to Spring Frosts
Authors: Kappel Frank
Published: February 2019

Spring frosts can be a limiting factor for sweet cherry production and very little is known about frost susceptibility of new sweet cherry cultivars. This study reports on floral bud injury of a number of recently introduced sweet cherry cultivars after 10 spring frosts in Apr. 2008. Floral buds at the first white stage were collected from late-ripening sweet cherry cultivars that were part of a randomized and replicated evaluation block. Blossoms were selected from various positions within a tree in a 1-m band centered around 1.5 m above the ground. The blossoms were brought into the laboratory, cut open, and placed into two groups: live (green) or dead (brown or browning) pistil. ‘Staccato’ and ‘Sentennial’ were the least affected followed by ‘Lapins’ and ‘Sweetheart’. ‘Sovereign’ was most susceptible to the subfreezing temperatures in the spring of 2008. There was a reasonably good relationship between the percentage of live buds per tree in the spring and yield at harvest later in the summer.
Evaluating Cover Crop Mulches for No-till Organic Production of Onions
Authors: Vollmer Emily R. , Creamer Nancy , Reberg-Horton Chris , Hoyt Greg
Published: February 2019

Cover crops of foxtail millet ‘German Strain R’ [Setaria italica (L.) Beauv.] and cowpea ‘Iron & Clay’ [Vigna unguiculata (L.) Walp.] were grown as monocrops (MIL, COW) and mixtures and compared with a bare ground control (BG) for weed suppression and nitrogen (N) contribution when followed by organically managed no-till bulb onion (Allium cepa L.) production. Experiments in 2006–2007 and 2007–2008 were each conducted on first-year transitional land. Mixtures consisted of cowpea with high, middle, and low seeding rates of millet (MIX-70, MIX-50, MIX-30). During onion production, each cover crop treatment had three N rate subplots (0, 105, and 210 kg N/ha) of surface-applied soybean meal [Glycine max (L.) Merrill]. Cover crop treatments COW and BG had the greatest total marketable onion yield both years. Where supplemental baled millet was applied in 2006–2007, onion mortality was over 50% in MIL and MIX and was attributed to the thickness of the millet mulch. Nitrogen rates of 105 and 210 kg N/ha increased soil mineral N (NO3– and NH4+) on BG plots 2 weeks after surface application of soybean meal each year, but stopped having an effect on soil mineral N by February or March. Split applications of soybean meal could be an important improvement in N management to better meet increased demand for N uptake during bulb initiation and growth in the spring.
Consumer Color Preferences for Single-stem Cut Flowers on Calendar Holidays and Noncalendar Occasions
Authors: Yue Chengyan , Behe Bridget K.
Published: February 2019

Flower color is a dominant attribute of fresh flowers, likely playing a key role in purchase preference. Several prior studies showed flower color preference differed by gender, but other information on color preferences is sparse. Data for this study were collected by the Ipsos-National Panel Diary Group for the American Floral Endowment, which maintained an extensive panel of consumer transactions from 1992 to 2005, including floral purchases. Multinomial logit analysis of single-stem cut flower purchases showed that men and women differed in their cut flower color preferences but that flower color preference also varied with demographic characteristics and by occasion. We grouped colors into six categories: BluePurple, RedBronze, PeachPink, White, Yellow, and Other. The highest percentage of flowers purchased were RedBronze (34%), whereas the lowest percentage of flowers were Yellow (10.01%) with Other flower colors accounting for less than 5% of purchases. Although women used a more diverse color palette, both men and women were more likely to buy RedBronze flowers for an anniversary and buy PeachPink flowers for Mother's Day. Between 1992 and 2005, women were less likely to purchase PeachPink flowers and men were less likely to purchase RedBronze over time. Overall demand for BluePurple and Yellow flower colors increased over time, whereas the demand for other color categories decreased over time.
Relationship of Shoot Dieback in Pecan to Fungi and Fruiting Stress
Authors: Reilly Charles C. , Wood Bruce W. , Stevenson Katherine L.
Published: February 2019

Two shoot dieback maladies (SDM) of pecan [Carya illinoinensis (Wangenh.) C. Koch] are of unknown cause and can adversely affect tree canopy health. They occur during either early spring (SpSDM) or early summer (SuSDM). Field studies found that both maladies predominantly occur on shoots retaining peduncles from the previous crop year's fruit cluster. Isolations of transition zone (from living to dead) tissue of symptomatic shoots, of 14 cultivars, found Phomopsis sp. in 89% or greater of samples and Botryosphaeria spp. in 40% or greater of sampled shoots. Isolations occasionally found some combination of eight other apparently saprobic fungal genera with individual genera typically present in 10% or less of symptomatic shoots but were always present in association with either Phomopsis sp. or Botryosphaeria spp. when shoots exhibited either SuSDM or SpSDM. The SpSDM form was associated with 10 cm or less of the shoot's length before budbreak in early March before expanding to 30 cm or greater by late June to produce the SuSDM form, thus, providing evidence for an ongoing and expanding infection common to both SDM forms. The incidence of both “Phomopsis-associated” SDM forms was greatest on trees likely exhibiting substantial stress, some of which was crop-associated. The consistent association of these two fungi with SDM indicates a role for one or both in its development; however, further pathogenicity research is needed to determine if they are the primary cause of these shoot dieback maladies and how they interact with stress factors. Linkage of Phomopsis sp., and possibly Botryosphaeria spp., to these two SDMs raises the possibility of significant canopy damage in prolific cultivars and emphasizes the importance of management practices that minimize stress in orchard trees.
Micropropagation of Oleander (Nerium oleander L.)
Authors: Vila Inmaculada , Sales Ester , Ollero Javier , Muñoz-Bertomeu Jesús , Segura Juan , Arrillaga Isabel
Published: February 2019

Successful propagation of Nerium oleander L. (oleander) was achieved by in vitro methods. Shoot cultures were initiated from seedlings of wild-growing plants and from shoot apices of adult plants belonging to the commercial cultivars Splendens Giganteum, Revanche, and Alsace. Axillary shoot breaking from shoot tips excised from these cultures required the presence of either 6-benzylaminopurine (BA) or thidiazuron (TDZ). The higher number of axillary shoots from juvenile material was obtained by culturing shoot tips from BA-pretreated material derived from seedlings on a modified Schenk and Hildebrandt medium (SHM) supplemented with BA or TDZ (average of 3.9 shoots per explant with a mean length of 10.4 mm) and when the media were supplemented with 8.8 μM TDZ (average of 3.5 shoots per explant with a mean length of 7.3 mm) or 4.4 μM BA (average of 3.3 shoots per explant with a mean length of 12.3 mm). Among cultivars, cv. Revanche showed best shoot proliferation rates, especially when explants were cultured on Woody Plant Medium (average of 3.2 shoots per explant with a mean length of 10.2 mm). Adventitious bud differentiation from oleander leaves is also reported. Leaves excised from seedling-derived shoot cultures responded better than those from adult plant-derived shoot cultures (40% versus 5%, respectively). Bud differentiation required the presence of TDZ in the SHM medium, although shoot development was only achieved on transference of explants to media without TDZ but supplemented with BA and indoleacetic acid (IAA) or BA, kinetin, and IAA. Axillary and adventitious shoots were easily rooted (99%) and successfully (95% to 100%) transferred to soil.
Simple Sequence Repeat Identification and Endocarp Characterization of Olive Tree Accessions in a Tunisian Germplasm Collection
Authors: Fendri Mahdi , Trujillo Isabel , Trigui Ahmed , Rodríguez-García María Isabel , de Dios Alché Ramírez Juan
Published: February 2019

Most traditional olive-producing countries possess a diversified genetic patrimony in Olea europaea L. Since the emergence of modern olive growing system, the identification, classification, and conservation of autochthonous olive cultivars is a priority for these countries. In this work, a total of 84 accessions belonging to the “Boughrara”-Sfax olive germplasm collection located in Tunisia have been screened using a powerful set of eight simple sequence repeat markers (SSRs). The study revealed a high genetic variability among the collection and detected a total of 64 alleles. For better management of the mentioned germplasm bank, an improved classification of the entries, including new denominations, has been proposed. In addition, several cases of mislabeling, synonymy, and homonymy have been clarified. Genetic relationships among cultivars have been analyzed showing four major clusters. Finally, a correspondence factor analysis demonstrated that cultivars tend to cluster depending on their main use as oil or table olives. No clear clustering tendencies were observed when the geographical origin of cultivars was used as the criteria for the analysis. All results obtained by SSR screening and classification were in accordance with classification based on morphological traits of fruit endocarps.
A Model for Scheduling Flowering of a Limonium sinuatum × Limonium perezii Hybrid
Authors: Chen Jianyu , Funnell Keith A. , Morgan Ed R.
Published: February 2019

Observations of leaf number accumulation rate (LNAR) and light integrals (DLI) were used to develop a predictive model for time to flower for a novel hybrid of Limonium sinuatum (L.) Mill. × Limonium perezii (Stapf) Hubb. Plants were established in a temperature-controlled greenhouse at seven planting times from fall to late spring. Long days were maintained using daylength extension lighting. Two light regimes, full sun or 50% shade, were also used. DLI was highly correlated with the time to appearance of the first visible flower bud, explaining in excess of 80% of the variation. When combined with plant growth variables describing either LNAR or rates of increase in groundcover index, a second model was able to predict the date of first visible flowers and accounted for more variation than DLI alone. Daily average temperature (DAT) did not significantly contribute to variation in time to first visible flower because temperatures were uniform between successive plantings at 18 to 21.7 °C. However, DAT was significant for the period from visible flower through to flower harvest maturity. Growers of these hybrids for cut flowers can therefore use historical records of DLI to determine planting dates to schedule flowering. Once planting has occurred, by measuring actual DLI, DAT, and leaf number per plant, growers can use the second model to more accurately predict the dates for visible flowers and flower harvest.
Early-season Extension Using June-bearing ‘Chandler’ Strawberry in High-elevation High Tunnels
Authors: Rowley Daniel , Black Brent L. , Drost Dan , Feuz Dillon
Published: February 2019

High tunnels have been used successfully in many areas of the world to extend the growing season for numerous crops. However, very little research has been conducted to evaluate the season extension benefits offered by high tunnels for small fruit crops in high-elevation growing areas such as the Intermountain West region of the United States. The use of high tunnels was investigated in North Logan, UT (lat. 41.766 N, elev. 1405 m, 119 freeze-free days) to extend the growing season for June-bearing strawberries. Growing systems included a fall-planted annual hill system and vertical growing systems in two different orientations. Optimum planting date for each system was determined by transplanting ‘Chandler’ plugs at 2-week intervals over 10 weeks. For the second year of the study, a field planting was also included. Over two seasons, the optimum planting dates were approximately the first week of September. The vertical systems were more susceptible to winter injury likely resulting from the temperature extremes in the root zone. Where winter injury was prevented, the vertical systems had higher yields per tunnel area than the in-ground system, but yield increases did not compensate for higher construction and management costs. The production window for the in-ground high tunnel planting was ≈4 weeks earlier than the field-grown plants and increased profitability by $13/m2 of tunnel area.
Variation in Formaldehyde Removal Efficiency among Indoor Plant Species
Authors: Kim Kwang Jin , Jeong Myeong Il , Lee Dong Woo , Song Jeong Seob , Kim Hyoung Deug , Yoo Eun Ha , Jeong Sun Jin , Han Seung Won , Kays Stanley J. , Lim Young-Wook , Kim Ho-Hyun
Published: February 2019

The efficiency of volatile formaldehyde removal was assessed in 86 species of plants representing five general classes (ferns, woody foliage plants, herbaceous foliage plants, Korean native plants, and herbs). Phytoremediation potential was assessed by exposing the plants to gaseous formaldehyde (2.0 μL·L−1) in airtight chambers (1.0 m3) constructed of inert materials and measuring the rate of removal. Osmunda japonica, Selaginella tamariscina, Davallia mariesii, Polypodium formosanum, Psidium guajava, Lavandula spp., Pteris dispar, Pteris multifida, and Pelargonium spp. were the most effective species tested, removing more than 1.87 μg·m−3·cm−2 over 5 h. Ferns had the highest formaldehyde removal efficiency of the classes of plants tested with O. japonica the most effective of the 86 species (i.e., 6.64 μg·m−3·cm−2 leaf area over 5 h). The most effective species in individual classes were: ferns—Osmunda japonica, Selaginella tamariscina, and Davallia mariesii; woody foliage plants—Psidium guajava, Rhapis excels, and Zamia pumila; herbaceous foliage plants—Chlorophytum bichetii, Dieffenbachia ‘Marianne’, Tillandsia cyanea, and Anthurium andraeanum; Korean native plants—Nandina domestica; and herbs—Lavandula spp., Pelargonium spp., and Rosmarinus officinalis. The species were separated into three general groups based on their formaldehyde removal efficiency: excellent (greater than 1.2 μg·m−3 formaldehyde per cm2 of leaf area over 5 h), intermediate (1.2 or less to 0.6), and poor (less than 0.6). Species classified as excellent are considered viable phytoremediation candidates for homes and offices where volatile formaldehyde is a concern.
Effect of Insecticidal Atmospheres at High Temperature Combined with Short Cold-quarantine Treatment on Quality of ‘Valencia’ Oranges
Authors: Contreras-Oliva Adriana , Rojas-Argudo Cristina , Pérez-Gago María B.
Published: February 2019

The combination of insecticidal atmosphere (IA) with short cold exposure periods has been effective in controlling the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). In the present work, ‘Valencia’ orange quality was assessed on fruit exposed to IA (95% CO2) at 23, 28, or 33 °C for 20 h; next stored at 1 °C for 8, 16, or 24 days; and then kept at 20 °C for 7 days to simulate shelf life. Physicochemical, sensory, and nutritional quality parameters were analyzed on treated and control (air-exposed) fruit. No significant negative effects on fruit quality were observed in IA-treated ‘Valencia’ oranges. In addition, the exposure of oranges to 95% CO2 at 28 °C reduced the weight and firmness loss compared with fruit kept in air. Ethanol content increased in the fruits exposed to 95% CO2 at 28 or 33 °C, but sensory quality was not adversely affected.
Benefits of Vermicompost as a Constituent of Growing Substrates Used in the Production of Organic Greenhouse Tomatoes
Authors: Surrage Victoria Ann , Lafrenière Claudia , Dixon Mike , Zheng Youbin
Published: February 2019

Six individual growing substrate components were selected. From the individual components, 35 growing substrates were constructed. Preliminary analyses, which included pH, electrical conductivity, and macro- and micronutrient concentrations, combined with environmental and cost implications were conducted to identify which substrates had the appropriate properties for growing tomatoes. From the 35 combinations, four growing substrates were chosen as having preferred properties required for organic greenhouse tomato production. A 22-week growth experiment was performed to determine if any of the selected substrates could improve the marketable yield of tomatoes when compared with rockwool (RW) under greenhouse conditions. The greenhouse crop used for this experiment was Lycopersicon esculentum ‘beefsteak’ tomato, cultivar Matrix F1 Hybrid. Within the experiment, Forterra Royal GRO 1 (GRO 1; coconut coir/vermicompost) and Forterra Royal GRO 2 (GRO 2; aged pine bark/coconut coir/vermicompost) attained significantly higher marketable yields per plant compared with the plants grown in RW. A similar trend was seen in the incidence of Blossom End Rot (BER) with GRO 1 and GRO 2 having reduced numbers of BER incidences per plant when compared with RW. In conclusion, the addition of vermicompost to organic growing substrates is beneficial for tomato growth and yield.
Increases in Bermudagrass [Cynodon dactylon (L.) Pers.] Tissue Pigments during Post-application Recovery from Mesotrione
Authors: Kopsell Dean A. , Brosnan James T. , Armel Gregory R. , McElroy J. Scott
Published: February 2019

Mesotrione {2-[4-(methylsulfonyl)-2-nitrobensoyl]-1,3-cyclohexanedione} is a herbicide that indirectly inhibits phytoene desaturase in plant tissues, the first step in the carotenoid biosynthesis pathway. The predominant symptom of mesotrione activity is tissue whitening with subsequent plant necrosis. In the current study, ‘Riviera’ bermudagrass [Cynodon dactylon (L.) Pers.] was treated with mesotrione at 0.28 kg·ha−1 or untreated and sampled for tissue pigment concentrations at 0, 3, 7, 14, 21, 28, and 35 days after treatment (DAT). Visual tissue whitening in mesotrione-treated plants reached a maximum of 38% by 14 DAT; however, regreening of discolored tissue was observed by 21 DAT. Phytoene was only detected in mesotrione-treated plants at 3, 7, and 14 DAT. Pigments in treated plants decreased with initial tissue whitening; however, most recovered to untreated levels by 21 DAT. At 35 DAT, chlorophyll a, chlorophyll b, lutein, β-carotene, and zeaxanthin in mesotrione-treated plants had accumulated to levels exceeding untreated control plants. Results demonstrate that although mesotrione initially decreases bermudagrass pigment concentrations, treatment with this herbicide eventually results in higher concentrations of chlorophylls and carotenoids.
Effects of Frequent Shearing on Root Growth and Mycorrhizal Colonization of Two Landscape Shrubs
Authors: Martin Chris A. , Whitcomb Sean A. , Stutz Jean C.
Published: February 2019

Leucophyllum frutescens I. M. Johnst. (Texas sage) and Nerium oleander L. (oleander) shrubs grown for 2 years in the southwest United States under well-watered conditions in outdoor field plots were either sheared every 6 weeks or not pruned (control) to determine if frequent shearing had an effect on root growth and mycorrhizal colonization. During February and June of the second year after transplanting, leaf gas exchange, shoot and root growth, and arbuscular mycorrhizal fungi (AMF) colonization of shrubs were studied. Shearing reduced shrub volume of Texas sage and oleander by 84% and 82%, respectively. Leaf carbon assimilation (A) and conductance of both shrub taxa were stimulated by frequent shearing, especially during June. Shearing decreased root mass density (RMD) and root length density (RLD) of Texas sage but had no impact on RMD or RLD of oleander. Shearing decreased the length of Texas sage roots colonized by AMF but increased AMF colonization of oleander roots. Soil respiration and temperatures were less under all shrubs that were frequently sheared than those that were not pruned and were higher under all shrubs in June than in February. From these data we conclude that under well-watered conditions, the rejuvenative capacity and resilience of oleander to the practice of frequent shearing is greater than Texas sage and recommend that Texas sage shrubs not be frequently sheared in southwest landscapes.
Weighing Lysimeters for Developing Crop Coefficients and Efficient Irrigation Practices for Vegetable Crops
Authors: Bryla David R. , Trout Thomas J. , Ayars James E.
Published: February 2019

Large, precision weighing lysimeters are expensive but invaluable tools for measuring crop evapotranspiration and developing crop coefficients. Crop coefficients are used by both growers and researchers to estimate crop water use and accurately schedule irrigations. Two lysimeters of this type were installed in 2002 in central California to determine daily rates of crop and potential (grass) evapotranspiration and develop crop coefficients for better irrigation management of vegetable crops. From 2002 to 2006, the crop lysimeter was planted with broccoli, iceberg lettuce, bell pepper, and garlic. Basal crop coefficients, Kcb, defined as the ratio of crop to potential evapotranspiration when the soil surface is dry but transpiration in unlimited by soil water conditions, increased as a linear or quadratic function of the percentage of ground covered by vegetation. At midseason, when groundcover was greater than 70% to 90%, Kcb was ≈1.0 in broccoli, 0.95 in lettuce, and 1.1 in pepper, and Kcb of each remained the same until harvest. Garlic Kcb, in comparison, increased to 1.0 by the time the crop reached 80% ground cover, but with only 7% of additional coverage, Kcb continued to increase to 1.3, until irrigation was stopped to dry the crop for harvest. Three weeks after irrigation was cutoff, garlic Kcb declined rapidly to a value of 0.16 by harvest. Yields of each crop equaled or exceeded commercial averages for California with much less water in some cases than typically applied. The new crop coefficients will facilitate irrigation scheduling in the crops and help to achieve full yield potential without overirrigation.
Growth and Physiological Responses of Landscape Plants to Saline Water Irrigation: A Review
Authors: Niu Genhua , Cabrera Raul I.
Published: February 2019

Water shortages and poor water quality are critical issues in many areas of the world. With rapid increases in population and shortage of water supplies in urban areas, use of alternative water sources such as municipal reclaimed water and other sources of non-potable waters for irrigating landscapes is inevitable. A potential concern is the elevated salt levels in these alternative waters. This article briefly summarizes general information regarding alternative water sources and general responses of landscape plants to salinity stress. Methodology of screening and evaluating salt tolerance of landscape plants are discussed. Recent research results on salt tolerance of landscape plants and their physiological responses to salinity stress are reviewed. Like agricultural crops, a wide range of salt tolerance among landscape plants has been found. In addition to plant species, dominant salt type, substrate, irrigation method and management, and environmental conditions also affect plant responses to salinity stress. A number of mechanisms of salinity tolerance have been observed among landscape species, including restriction of ion uptake, selective ion uptake, and tolerance to high internal concentrations of sodium and/or chloride.
Efficient Irrigation for Optimum Fruit Quality and Yield in Apples
Authors: Fallahi Esmaeil , Neilsen Denise , Neilsen Gerry H. , Fallahi Bahar , Shafii Bahman
Published: February 2019

Use of crop evapotranspiration (ETc), when a precise crop coefficient value (Kc) is used, provides a reliable tool (irrigation scheduling) for determination of water requirement. In this process, Kc should be modified by percentage of ground shade (GS) and tree canopy maturity (M). In an experiment in Idaho with ET-based irrigation scheduling, each tree with a full microjet sprinkler system received an average of 6461.7 L (994 mm), whereas each one with a full drip system used 3996 L (614.1 mm) of irrigation water. In general, deficit drip irrigation was shown to initially increase yield as a result of induction of stress and the production of a higher number of fruit spurs. However, production declined if the extreme water deficiency was repeatedly applied to the trees over several years. Using a microjet sprinkler system, a partial root zone drying regime reduced fruit size but slightly improved fruit color. Application of water at 65% full drip rate, applied on both sides of the tree row (DD), reduced fruit size. However, when the 65% of full drip rate was applied to only one of the alternating sides of the tree every other week (PRD), fruit size was larger than those with DD treatment.
A Study of Compost Added to a Casing Technique in Agaricus bisporus Cultivation from Phase III Bulk Compost
Authors: Zied Diego Cunha , Almeida Minhoni Marli Teixeira , Pardo-González J. Emilio , Pardo-Giménez Arturo
Published: February 2019

The aim of this study was to assess the effect of the addition of different rates of colonized compost and formaldehyde treatment on production parameters (yield, biological efficiency, mushroom number, mushroom weight, and earliness) in a Dutch commercial casing using Phase III bulk compost as a base substrate for growing Agaricus bisporus. Four rates of spawn-run compost (0 g·m−2, 200 g·m−2, 400 g·m−2, and 600 g·m−2) and formaldehyde treatment (with or without) were used. The experiment was designed as a double factorial in a randomized complete block design. Each block contained six replicates per treatment (a compost bag with 20 kg). The compost added to casing (CACing) technique when applied properly and combined with the use of Phase III compost had significant benefits, including increased mushroom yield, weight, and reduced the growing cycle, especially with the rate of 600 g of spawn-run compost/m2 of casing. On the other hand, the application of formalin reduced yield with or without the CACing technique, which implies the need for an alternative treatment for disinfection. An alternative method may either be thermal or chemical treatments to the casing such as using formaldehyde before mixing the casing with spawn-run compost and before the addition of casing above the colonized compost.