bluuebunny/crossref_metadata_2025 huggingface dataset:
Resistance to Phytophthora Fruit Rot of Watermelon Caused by Phytophthora capsici in U.S. Plant Introductions
Authors: Kousik Chandrasekar S. , Ikerd Jennifer L. , Wechter Patrick , Harrison Howard , Levi Amnon
Published: February 2019

Phytophthora fruit rot, caused by Phytophthora capsici, is prevalent in most watermelon-producing regions of southeastern United States and is known to cause pre- and post-harvest yield losses. A non-wound inoculation technique was developed to evaluate detached mature fruit belonging to U.S. watermelon PIs for resistance to fruit rot caused by P. capsici. Mature fruit were harvested and placed on wire shelves in a walk-in humid chamber [greater than 95% relative humidity (RH), temperature 26 ± 2 °C] and inoculated with a 7-mm agar plug from an actively growing colony of P. capsici. Twenty-four PIs that exhibited resistance in a preliminary evaluation of 205 PIs belonging to the watermelon core collection in 2009 were grown in the field and greenhouse in 2010 and 2011 and evaluated in the walk-in humid chamber. Fruit rot development was rapid on fruit of susceptible controls ‘Black Diamond’, ‘Sugar Baby’, and PI 536464. Several accessions including PI 560020, PI 306782, PI 186489, and PI 595203 (all Citrullus lanatus var. lanatus) were highly resistant to fruit rot. One C. colocynthis (PI 388770) and a C. lanatus var. citroides PI (PI 189225) also showed fruit rot resistance. Fruit from PIs that were resistant also had significantly lower amounts of P. capsici DNA/gram of fruit tissue compared with the susceptible commercial cultivars Sugar Baby and Black Diamond. The sources of resistance to Phytophthora fruit rot identified in this study may prove useful in watermelon breeding programs aimed at enhancing disease resistance.
Increased Oxygen Bioavailability Improved Vigor and Germination of Aged Vegetable Seeds
Authors: Liu Guodong , Porterfield D. Marshall , Li Yuncong , Klassen Waldemar
Published: February 2019

Large and/or aged seeds are prone to hypoxic conditions during germination. Germination of selected vegetable seeds including corn (Zea mays L.), squash (Cucurbita pepo L.), and tomato (Solanum lycopersicum L.) was studied in water with different concentrations of hydrogen peroxide (H2O2) solution ranging from 0, 0.06% to 3.0% (v/v) or in aeroponics, all with 0.5 mm CaSO4. Imbibition, oxygen consumption, proton extrusion, and alcohol dehydrogenase (ADHase) activity of corn seeds were measured gravimetrically, electrochemically, and colorimetrically as appropriate. The results showed that 0.15% H2O2 provided the optimum oxygen concentration for seed germination. The germination percentage of aged corn seeds treated with H2O2 was significantly greater than those without H2O2 treatment. Corn embryo orientation in relation to a moist substrate also significantly impacted oxygen bioavailability to the embryo and hence ADHase activity. Corn seeds without H2O2 imbibed significantly more slowly than those with oxygen fortification by 0.15% H2O2. Increased oxygen bioavailability improved the metabolism of the seeds, which extruded 5-fold more protons from the embryos. Each treated embryo consumed twice the amount of oxygen as compared with the untreated one and likewise for treated and untreated endosperms. Increased oxygen bioavailability may be used to improve production of the tested crops. The results from this research imply that consideration should be given to including oxygen fortification in seed coatings for aged seeds and for large seeds regardless of age. The artificial provision of bioavailable oxygen might be effective in rescuing the germplasm in aged seeds in plant breeding and in crop production.
Abscisic Acid Effect on Improving Horse Chestnut Secondary Somatic Embryogenesis
Authors: Ćalić Dušica , Devrnja Nina , Milojević Jelena , Kostić Igor , Janošević Dušica , Budimir Snežana , Zdravković-Korać Snežana
Published: February 2019

The effect of abscisic acid on the development of primary androgenic embryo and secondary somatic embryogenesis was investigated with the aim of improving multiplication rates and secondary somatic embryo quality in horse chestnut microspore and anther culture. The early embryo stage (globular) had a better response than late stages (heart, torpedo, and cotyledonary) in both types of cultures. Also, microspore culture had a high potential for mass secondary embryo production. The number of secondary somatic embryos was three times higher on hormone-free medium than on medium enriched with 0.01 mg·L−1 abscisic acid. However, most of the embryos on hormone-free medium had abnormal morphology. For this reason, abscisic acid was added to the media to improve embryo quality. The morphology of abscisic acid treated embryos was better than abscisic acid non-treated embryos. The optimal abscisic acid concentration for secondary somatic embryo induction and production of high-quality embryos was 0.01 mg·L−1. Overall, the effect of abscisic acid on the induction of secondary somatic embryogenesis and plant regeneration of androgenic embryos of this species may be helpful for the further synthesis of secondary metabolites in vitro and their application in the pharmaceutical industry.
Ethephon and Methyl Jasmonate Affect Fruit Detachment in Rabbiteye and Southern Highbush Blueberry
Authors: Malladi Anish , Vashisth Tripti , Johnson Lisa Klima
Published: February 2019

Two abscission agents, ethephon and methyl jasmonate, were investigated in five studies to determine their potential for increasing fruit detachment during harvest in rabbiteye (Vaccinium ashei Reade) and southern highbush (hybrids based largely on Vaccinium corymbosum L. and Vaccinium darrowi Camp.) blueberry. In the first study with a rabbiteye blueberry genotype, T-451, ethephon applications up to 1000 mg·L−1 did not affect fruit drop but reduced fruit detachment force (FDF) by up to 21%. In the second study with two southern highbush blueberry genotypes, ethephon (up to 1500 mg·L−1) and methyl jasmonate (MeJa; up to 10 mm) applications resulted in significant fruit drop in ‘Star’ but neither of the growth regulators affected the fruit detachment characteristics of ‘Farthing’. In a third study with rabbiteye blueberry genotypes, MeJa applications of 10, 20, and 30 mm displayed an increasing linear trend in fruit drop in ‘Climax’ and linear and quadratic trends in fruit drop in ‘Powderblue’. In a fourth study with ‘Powderblue’, MeJa (20 mm) and ethephon (1000 mg·L−1) applications resulted in rapid and significant fruit drop. The fruit drop induced by MeJa in this study was attenuated by the coapplication of aminoethoxyvinylglycine (AVG), an ethylene biosynthesis inhibitor, suggesting that MeJa induced fruit detachment partly through its effects on ethylene biosynthesis. In another study with the southern highbush blueberry genotype, O’Neal, MeJa applications (20 mm) induced significant fruit drop but ethephon (1000 mg·L−1) applications did not affect fruit detachment. Overall, MeJa applications (20 mm or greater) generally induced rapid and extensive fruit abscission, often within 1 day after treatment. Applications of MeJa resulted in leaf yellowing and necrosis of leaf tips and margins, especially at high rates of application (20 mm or greater). Ethephon applications resulted in the abscission of mature and immature berries. Both ethephon and MeJa applications resulted in the detachment of the pedicel along with the fruit. Together, these data suggest that although ethephon and MeJa have the potential to be used as harvest aids in blueberry, the rates of application require further optimization to minimize potential phytotoxicity. Additionally, effective de-stemming of the berries may be essential if these compounds are to be used as harvest aids.
Microbiological Quality and Shelf Life of Enzyme-peeled Fresh-cut Persimmon Slices Stored in High CO2 Atmospheres
Authors: Murakami Yukari , Ozaki Yoshihiko , Izumi Hidemi
Published: February 2019

The microbiological quality and shelf life of enzyme-peeled fresh-cut persimmon slices were evaluated during storage in a high CO2 controlled atmosphere (CA) and active modified atmosphere packaging (MAP) at 10 °C. Microbial counts of the enzyme-peeled slices were lower in high CO2 atmospheres (10%, 15%, and 20%) than in air during CA storage for 6 days at 10 °C with the 20% CO2 atmosphere being most effective. High CO2 atmospheres did not affect the number of bacterial and fungal species detected in the persimmon slices. The surface color, expressed as C* values, of the peeled side of enzyme-peeled slices was lower in high CO2 than in air after 6 days of CA storage. In contrast, C* values at the cut side were higher for slices stored in 20% CO2 than in air on Day 6. High CO2 atmospheres did not affect other quality of enzyme-peeled slices such as texture, pH, sugar content, and total ascorbic acid content. Based on the optimum 20% CO2 concentration in a CA, enzyme-peeled slices were stored in a MAP flushed with either air or 20% CO2 for 4 days at 10 °C. The CO2 concentration approached an equilibrium of either 5% or 10% after 3 days of storage in packages flushed with either air or 20% CO2, respectively, and the O2 decreased to ≈10% in both packages. Adding 20% CO2 to the MAP was effective in reducing the growth of mesophiles and coliforms but not fungi in enzyme-peeled persimmon slices throughout 4 days of storage. The diversity of bacterial and fungal flora was partially similar between packages flushed with air and 20% CO2. Texture, pH, surface color, sugar content, and total ascorbic acid content of enzyme-peeled persimmon slices were unaffected by air or 20% CO2 as the flushing gas, except that C* values of the enzymatically peeled side on Day 4 were lower for slices flushed with 20% CO2 than air. A 20% CO2 atmosphere is recommended for reducing the microbial population of enzyme-peeled persimmon slices stored at 10 °C and the shelf life of persimmon slices in an active MAP with 20% CO2 is 4 days at 10 °C.
Storage Time and Amendments Affect Pine Tree Substrate Properties and Marigold Growth
Authors: Taylor Linda L. , Niemiera Alexander X. , Wright Robert D. , Harris J. Roger
Published: February 2019

Pine tree substrate (PTS) is a relatively new alternative to the commonly used pine bark and peat-based substrates for container crop production. Physical and chemical properties of freshly manufactured PTS have been studied; however, this new substrate will sometimes be manufactured and stored for later use by growers. The objective of this research was to determine how chemical and physical properties of PTS were affected by storage duration with or without amendments of limestone or peatmoss. We also studied how the growth of marigold was influenced by PTS storage time and by lime and peat amendments. Substrate properties studied were pH, cation exchange capacity (CEC), electrical conductivity (EC), carbon-to-nitrogen ratio (C:N), bulk density (BD), and particle size distribution. Pine tree substrate was manufactured by hammermilling chips of ≈15-year-old loblolly pine trees (Pinus taeda L.) through two screen sizes, 4.76 mm (PTS) and 15.9 mm [amended with peat (PTSP)]. Pine tree substrate and PTSP were amended with lime at five rates and a peat–perlite mix (PL) served as a control treatment. Substrates were prepared, placed in plastic storage bags, and stored on shelves in an open shed in Blacksburg, VA. Substrates were subsampled at 1, 42, 84, 168, 270, and 365 days after storage. At each subsampling day, twelve 1-L containers were filled with a subsample of each treatment. Six of the 12 were left fallow and six were planted with 14-day-old marigold (Tagetes erecta L. ‘Inca Gold’) seedlings. Substrate was also collected for analysis of CEC, C:N, BD, and particle size distribution. The pH of non-limed PTS decreased during storage, and at least 1 kg·m−3 lime was needed to maintain PTS pH 5.4 or greater over the 365-day storage period (Day 1 pH = 5.8) and 2 to 4 kg·m−3 was needed to maintain PTSP pH 5.4 or greater for 365 days (Day 1 pH = 5.2). EC measurements were highest at Day 1 (1.02 to 1.21 dS·m−1) in all treatments and decreased by Day 42. Cation exchange capacity decreased over time in non-limed PTS and PTSP. Carbon-to-nitrogen ratio and BD remained the same over time for all treatments. There were minor changes in particle size distribution for limed PTS. Marigold growth in all limed PTS and PTSP treatments was equal to or greater than in PL, except at Day 1; the lower growth in PTS and PTSP at Day 1 compared with PL suggests that freshly manufactured PTS may contain a phytotoxic substance that was not present in PTS by Day 42. Pine tree substrate and PTSP are relatively stable when stored as described previously, except for a pH decrease that can be prevented with additions of lime before storage.
Chilades pandava Damage among 85 Cycas Species in a Common Garden Setting
Authors: Marler Thomas E. , Lindström Anders J. , Terry L. Irene
Published: February 2019

The extent of Chilades pandava Horsfield herbivory among 85 Cycadaceae species was determined by three evaluators in a common garden setting in Thailand to identify patterns that may improve horticultural and conservation management practices. The significant differences in herbivory damage from this invasive lepidopteran pest ranged 8.7-fold among the species. Phylogenetic sections of this monogeneric cycad family did not correspond to the relative differences among the species, and country of nativity was also not informative for this purpose. We suggest the Cycas L. species that share native habitat with this butterfly or the closely related Theclinesthes onycha Hewitson are among the least damaged taxa when they are comingled with other Cycas species in a common landscape. Grouping the most damaged Cycas species together in a managed landscape may reduce costs associated with plant protection. The inclusion of non-native Cycas plants in gardens nearby native Cycas habitats carries the potential of disrupting the delicate specialist relationship that native butterfly populations have with host Cycas species.
Soaking Temperature of Dried Tuberous Roots Influences Hydration Kinetics and Growth of Ranunculus asiaticus (L.)
Authors: Cerveny Christopher B. , Miller William B. , Björkman Thomas , Mattson Neil S.
Published: February 2019

The published literature is inconsistent with recommendations for hydrating Ranunculus asiaticus (L.) dried tuberous roots, a common practice in commercial production systems for this ornamental geophyte. Imbibition rate increased with hydration temperature but to lower equilibrium moisture content than when hydrated at cooler temperatures. In the greenhouse, survival was predicted to be greatest when tubers were hydrated at 20 °C. Plant height, visual quality, and foliar dry weight followed a similar trend 4 weeks after planting. These results demonstrate that a hydration temperature between 15 and 25 °C is required to obtain good quality when growing R. asiaticus from its dried tuberous roots.
Roller Type and Operating Speed Effects on Rye Termination Rates, Soil Moisture, and Yield of Sweet Corn in a No-till System
Authors: Kornecki Ted S. , Arriaga Francisco J. , Price Andrew J.
Published: February 2019

A field experiment was conducted in Cullman, AL, to evaluate the effects of three different rollers/crimpers on the termination of a rye (Secale cereale L) winter cover crop, soil moisture, and yield of sweet corn (Zea mays saccharata L.) in a no-till system. The following roller types were tested: a straight bar roller, a smooth roller with crimper, and a two-stage roller. These rollers were tested at operating speeds of 3.2 km·h−1 and 6.4 km·h−1. The three rollers/crimpers were compared with a smooth drum roller (no crimping bars) plus glyphosate applied at rate 1.0 kg·ha−1 used as a control. Rye termination dates were selected to be 3 weeks before the recommended sweet corn planting date, which is in the beginning of May for this region. Data indicate that at 3 weeks after rolling for all seasons (2006–2008), 100% rye termination was reached with the smooth drum roller and glyphosate. Two weeks after rolling, average rye termination rates by rollers/crimpers alone were 54.6%, 30.0%, and 50.4% in 2006, 2007, and 2008, respectively. Three weeks after rolling, rye termination rates increased only by ≈10% compared with 2 weeks after rolling. These termination levels were below the recommended rate of 90% termination necessary for planting a cash crop into the cover residue. Lower rye termination was probably caused by rolling the rye in an early growth stage (flowering stage). The rollers’ operating speed did not influence rye termination rates. Similarly, roller type did not affect soil moisture during the first and second week after rolling. Applying glyphosate with rolling did not increase yield of sweet corn in any of the three growing seasons, and in 2006, sweet corn yield was lower compared with the roller alone treatments. These results are important to vegetable organic systems, in which use of herbicides is not allowed. No significant difference in sweet corn yield was found between operating speeds of 3.2 km·h−1 vs. 6.4 km·h−1 and between the assigned treatments in all growing seasons. However, significant differences in sweet corn yield were detected between the years, most likely as a result of different weather patterns. The lowest sweet corn yield of 3513 kg·ha−1 was reported in 2007 as a result of severe drought in spring and summer of 2007. The highest yield of 15,613 kg·ha−1 was recorded in 2006. In 2008, the yield was 10,158 kg·ha−1. Although the different roller designs were not as effective in ending the rye cover crop compared with the glyphosate treatment, sweet corn yields were unaffected. Multiple rolling operations over the same area could be useful if greater rye termination levels are required without the use of a herbicide, but this recommendation should be tested experimentally in more detail.
Relative Effects of Fertilizer Nitrogen Form and Phosphate Level on Control of Bedding Plant Seedling Growth
Authors: Nelson Paul V. , Song Cheon-Young , Huang Jinsheng , Niedziela Carl E. , Swallow William H.
Published: February 2019

Fertilizers with a high proportion of nitrogen (N) in the nitrate (NO3–) form are used in the ornamental industry to promote compactness in plants. Although the common belief is that it is the high proportion of NO3– that causes compactness, these formulations also contain no or a low level of phosphate, which can also cause compactness. This study was conducted to assess the relative effects of NO3– to ammonium (NH4+) ratio and phosphate supply, as found in high NO3– fertilizers, on seedling shoot growth. A series of fertilizers was formulated in which the level of phosphate and proportion of N in the NO3– form were varied factorially. Additionally, commercial fertilizers varying in these same two nutrient components were tested to verify the results obtained using the formulated fertilizers. Test plants included gomphrena (Gomphrena globosa L.), impatiens (Impatiens wallerana Hook. F.), petunia (Petunia ×hybrida Juss.), marigold (Tagetes erecta L.), and tomato (Solanum esculentum Mill.) grown as plug seedling crops. A strong inverse relationship occurred between the supply of phosphate and extent of compactness. The relationship between proportion of N in the NO3– form and compactness was comparatively small. In most comparisons within the study, shoot size increased with increasing proportion of NO3–, contrary to common belief. These data indicate that it is the limited phosphate level in high NO3– fertilizers that accounts for compactness rather than the high proportion of N in the NO3– form.
Development of a Simple Reference Evapotranspiration Model for Irrigation of Woody Ornamentals
Authors: Beeson Richard C.
Published: February 2019

Rooted cuttings of Rhaphiolepis indica, a low slow-growing evergreen shrub, were grown outdoors in weighing lysimeters to market size in 11.4-L containers. Actual evapotranspiration (ETA) and evaporation from containers shaded with plastic foliage was determined daily. The first 60 days after transplanting, substrate evaporation accounted for most of ETA and was the major component through the first 127 days. ETA generally followed variations in reference evapotranspiration (ETo). Mean cumulative ETA to produce 90% of measured plants to market size was 101 L or 1.99-m depth per plant based on container surface area. Water need indices, similar to crop coefficients, were highly correlated with percent canopy closure using an exponential decay equation (r2 = 0.898), but a more precise estimate at higher canopy closures was achieved using a third-order inverse polynomial equation (r2 = 0.907). When combined with similar previous data from Viburnum odoratissimum and Ligustrum japonicum, the inverse polynomial equation correlation was 0.802 for all three shrubs. This implies the %Closure model provides a good general base for ETo-based irrigation of woody evergreen shrub species based on canopy size and spacing with improved precision when individual equations are derived by species.
Lavandula angustifolia Growth and Physiology Is Affected by Substrate Type and Depth When Grown under Mediterranean Semi-intensive Green Roof Conditions
Authors: Kotsiris George , Nektarios Panayiotis A. , Paraskevopoulou Angeliki T.
Published: February 2019

Green roofs have received increased interest as a result of their environmental, social, and economic benefits. The present study aims to evaluate suitable, lightweight substrates for the installation of semi-intensive-type green roofs and their effects on Lavandula angustifolia growth and physiological status under Mediterranean climatic conditions. The study was conducted in field containers (1.2 × 1.2 m), and treatments included the use of two depths (20 cm or 30 cm) and three different substrates: 1) pumice (Pum) mixed with peat (P) and zeolite (Z) in a volumetric proportion of 65:30:5 (Pum65:P30:Z5); 2) pumice mixed with compost (C) and zeolite in a volumetric proportion of 65:30:5 (Pum65:C30:Z5); and 3) sandy loam soil (S) mixed with perlite (Per) and zeolite in a volumetric proportion of 30:65:5 (S30:Per65:Z5). Each experimental plot was planted with four plants of L. angustifolia. The physical and chemical characteristics of the substrates and the in situ substrate moisture levels were determined. Plant growth was determined by the growth index and root dry weight, whereas the plant physiological status during the stressful summer period was determined by chlorophylla+b content and stomatal resistance. It was found that the bulk density of all of the substrates was less than 0.8 g·cm−3, whereas the water retention of substrate S30:Per65:Z5 was greater than the other two substrates at all tensions. Substrate depth was the most influential factor; therefore, the deeper substrates (30 cm) provided higher growth indices and root dry weight, increased total chlorophyll content, and reduced leaf stomatal resistance compared with the shallower substrate depth of 20 cm. Differences between substrate types were smaller compared with those of substrate depth. In spring, the growth index in substrate Pum65:C30:Z5 was larger but not in the summer when the growth index of substrates S30:Per65:Z5 and Pum65:P30:Z5 exceeded that of the substrate amended with compost until the end of the study. In late summer, the plant total chlorophyll content decreased in all substrates, whereas substrate Pum65:C30:Z5 exhibited increased stomatal resistance compared with the other two substrates at the same period. It was concluded that L. angustifolia could be grown successfully in semi-intensive Mediterranean green roofs at a substrate depth of 20 cm, but its growth and tolerance to the harsh summer conditions would improve at a substrate depth of 30 cm.
Influence of Harvest Intervals on Growth Responses and Fatty Acid Content of Purslane (Portulaca oleracea)
Authors: Mortley Desmond G. , Oh Jun-Hyun , Johnson Damicca S. , Bonsi Conrad K. , Hill Walter A.
Published: February 2019

A greenhouse study was conducted to evaluate the influence of harvest intervals on biomass yield and omega fatty acids of ‘Golden purslane’ (Portulaca oleracea). Nutrients were supplied as a modified full-strength Hoagland solution two to three times weekly. Plants were harvested sequentially at 20, 40, and 60 days after transplanting (DAT) corresponding to 42, 63, and 84 days after sowing. Fatty acids were determined using a gas chromatography–mass spectrometry. Harvest intervals significantly influenced foliage fresh and dry weight, leaf number and plant height, and root length and fresh weight and were greatest at 60 DAT. Fatty acid analysis verified the presence of myristate, palmitate, linoleate, and linolenate at 20 DAT and in all three harvests, whereas stearate and oleate were detected only in the last two harvests (40 and 60 DAT). Linoleate, palminate, and linolenate were the most abundant fatty acids in purslane with levels in excess of 300 mg·kg−1. Those for myristate, stearate, and oleate were in excess of 200 mg·kg−1. The ratio of omega-6/omega-3 ranged from 0.44 for Harvest 1 to 1.1 for Harvest 3, whereas ratios for harvest intervals two and three were equal to or greater than the recommended daily human requirement. Results showed qualitative and quantitative differences of harvest intervals of purslane, suggesting that an optimal ratio of omega-6 to omega-3 fatty acids can be achieved ≈20 DAT.
Quantification of Carbon Assimilation of Plants in Simulated and In Situ Interiorscapes
Authors: Pennisi Svoboda V. , van Iersel Marc W.
Published: February 2019

Interiorscape plants have many documented benefits, but their potential for carbon sequestration is not clear. This study was undertaken to quantify the amount of carbon assimilation under growth chamber conditions designed to mimic the photosynthetic photon flux (PPF) levels and temperatures of typical indoor environments and to quantify the amount of carbon assimilation in situ in a representative interiorscape composed of a variety of plant species and sizes. Quantitative data were obtained in 1) growth chambers with a typical range of PPF levels encountered indoors (≈10, 20, and 30 μmol·m−2·s−1); and 2) in situ conditions in an interiorscape. Under growth chamber conditions, most species exhibited positive dry mass accumulation and carbon sequestration but Sanseveria and Dracaena ‘Janet Craig’ exhibited consistent dry mass loss throughout the 10 weeks under simulated conditions. Carbon content was lower in herbaceous species (e.g., Scindapsus aureus, 38% of dry mass) compared with woody ones (e.g., Ficus benjamina, 43%). PPF-saturated net photosynthetic rates of plants were low, ranging from 3.4 to 7.0 μmol·m−2·s−1, whereas their light compensation points ranged from 8 to 78 μmol·m−2·s−1. In situ, plants exhibited varying dry mass gain, largely dependent on size. In general, a large plant and/or species with a higher amount of woody tissue in their above- or belowground organs (e.g., 4.6 m high arboreal plant) sequestered more carbon than small and/or herbaceous species. This study is the first to provide quantitative data of carbon sequestration in interiorscape environments.
Molecular Analysis for Conservation of Georgia Plume, a Threatened Endemic, Using Random Amplified Polymorphic DNA
Authors: Porter Justin A. , Wetzstein Hazel Y. , Berle David , Wadl Phillip A. , Trigiano Robert N.
Published: February 2019

Georgia plume, Elliottia racemosa (Ericaceae), is a small tree endemic only to the state of Georgia, where it is listed as a threatened species. Information about genetic relatedness is critical for establishing approaches for safeguarding, reintroduction, and conservation of this rare species. The genetic relationships among and within selected georgia plume populations were evaluated using random amplified polymorphic DNA (RAPD) in conjunction with site visits at which time a census and GPS survey were conducted. Populations ranged from those containing eight to over 1000 individuals with most populations containing few plants (less than 50 individuals). With one exception, small populations with less than 50 individuals had more genetic similarity than populations with greater numbers of plants. Two protected populations containing large numbers of individuals were sampled extensively. Genetic similarity of individuals was not associated with plant proximity within a population. The small number of individuals and geographic isolation characteristic of many populations were associated with high within-population genetic similarity. Conservation priorities should be given to preserving as many different populations as possible to retain the genetic diversity of the species. Whether the narrow genetic variation found in some populations may be contributing to lack of sexual reproduction in the wild is an area for further study.
Mitigation of Salt Stress in Lettuce (Lactuca sativa L. var. Crispa) by Seed and Foliar 24-epibrassinolide Treatments
Authors: Ekinci Melek , Yildirim Ertan , Dursun Atilla , Turan Metin
Published: February 2019

The objective of this study was to determine the effect of 24-epibrassinolide (24-EBL) applications on growth, chlorophyll, and mineral content of lettuce (Lactuca sativa L. var. Crispa) grown under salt stress. The study was conducted in pot experiments under greenhouse conditions. Lettuce seedlings were treated with seed and foliar 24-EBL applications at different concentrations (0, 1, 2, and 3 μM). Salinity treatments were established by adding 0, 50, and 100 mm of sodium chloride (NaCl) to a base complete nutrient solution. Results showed that salt stress negatively affected the growth and mineral content of lettuce plants. However, seed and foliar applications of 24-EBL resulted in greater shoot fresh weight, shoot dry weight, root fresh weight, and root dry weight as well as higher stem diameter than the control under salt stress. Salinity treatments induced significant increases in electrolyte leakage of plant, but foliar 24-EBL application reduced leaf electrolyte leakage and has determined lower values of leaf electrolyte leakage than non-treated ones. In regard to nutrient content, it can be inferred that 24-EBL applications increased almost all nutrient content in leaves and roots of lettuce plants under salt stress. Generally, the greatest values were obtained from 3 μM 24-EBL application. Treatments of 24-EBL alleviated the negative effect of salinity on the growth of lettuce.
Gibberellic Acid Sensitivity among Common Bean Cultivars (Phaseolus vulgaris L.)
Authors: Pavlista Alexander D. , Santra Dipak K. , Schild James A. , Hergert Gary W.
Published: February 2019

To lower seed yield loss from directly harvested common bean or dry bean, height of the lower pod-bearing nodes needs to be raised. The objective of this greenhouse study was to stimulate lower stem elongation by gibberellic acid (GA3) of dry bean cultivars. Seeds of cv. Matterhorn, erect indeterminate Type II, and cv. Poncho, prostate indeterminate Type III, were dipped in GA3 at 62.5 to 16,000 ppm and planted. After 14 d, the height of the unifoliate and first trifoliate nodes showed maximum stimulation of stem elongation by 1000 ppm GA3 for ‘Poncho’ and by 2000 ppm for ‘Matterhorn’. Application of 1 mL of GA3 at 0.031 to 2048 ppm to newly expanded unifoliate leaves showed cultivar differences. Whereas ‘Matterhorn’ was promoted at 64 ppm and reached a maximum height by 512 ppm GA3, ‘Poncho’ was promoted at 0.25 ppm and reached a maximum height by 8 ppm GA3. Flowering of ‘Matterhorn’ was unaffected by GA3; flowering of ‘Poncho’ was completely inhibited by 128 ppm. The sensitivity difference of cultivars was verified with other cultivars. Type I cultivars, which are all determinate, showed a full range of GA3 sensitivity. Dry bean cultivars may be regrouped based on the GA3 dose to which they respond. Individual response to GA3 rates of dry bean cultivars needs to be predetermined using a short-term, 2–3 weeks, greenhouse bioassay before field use of GA3.
Emerging Methods for Diagnostics and Mitigation of Crop Environmental Stress in a Changing Climate
Authors: Kim Soo-Hyung , Cregg Bert
Published: February 2019

Innovative approaches are required for improving crop productivity and quality to meet the increasing demand for providing food, energy, and other services for growing populations in a changing climate. The colloquium sponsored by the Environmental Stress Physiology (STRS) Working Group at the 2011 American Society for Horticultural Science (ASHS) annual conference served as a forum to bring together several of the emerging methods for diagnosing, monitoring, and mitigating crop environmental stress with an emphasis on horticultural, physiological, and ecological approaches. These methods are likely to be readily applicable for many research areas in specialty crops in the context of climate change. The colloquium articles in this volume provide a foundation and context to lead dialogues and initiate research themes for developing adaptive strategies to minimize climate impacts on horticultural crop production in a changing climate.
Effect of Smoke-water on Seed Germination and Seedling Growth of Papaya (Carica papaya cv. Tainung No. 2)
Authors: Chumpookam Jenjira , Lin Huey-Ling , Shiesh Ching-Chang
Published: February 2019

Smoke-water is a chemical extract used to stimulate the germination of many plant species under cultivation. This study evaluated the efficacy of smoke-water on the seed germination and seedling growth of papaya (Carica papaya cv. Tainung No. 2). Smoke-water, prepared from dry rice straw (Oryza sativa) by burning and bubbling the smoke through water, was used for germination experiments, growth experiments, and anatomical structure changes of seeds. In the germination experiments, papaya seeds were soaked with different concentrations of smoke-water (0.1%, 0.2%, 1%, 2%, 3%, 4%, 5%, 7%, or 10%, v/v) for 24 h before planting. Low concentrations of smoke-water (0.1% or 0.2%, v/v) not only promoted the maximum rate of germination, but also shortened the germination time. Analysis of longitudinal sections of seeds treated with smoke-water concentrations of 0.1% or 0.2% v/v suggested that smoke-water could overcome water impermeability barriers, because it stimulated the seedcoat to rupture and allowed the radical to elongate and emerge faster. In the growth experiments, papaya seedlings were transplanted into peatmoss-filled pots that were saturated with different concentrations of smoke-water (0%, 1%, 2%, 3%, 4%, 5%, 7%, or 10%, v/v). Results showed that all growth parameters increased significantly compared with the control. In addition, smoke-water treatments consistently and significantly increased the percentage of nitrogen in roots and shoots and significantly increased the percentage of magnesium in shoots. In these experiments, smoke-water showed potent germination promotion at low concentrations and promoted multiple growth attributes such as chlorophyll content and seedling vigor index at all concentrations in papaya seedling production.
Relationship of Black Vine Weevil Egg Density and Damage to Two Cranberry Cultivars
Authors: Miller Betsey , Bruck Denny J. , Walton Vaughn
Published: February 2019

Black vine weevil (BVW), Otiorhynchus sulcatus (Coleoptera: Curculionidae, Fabricius), is a serious pest of cranberry, Vaccinium macrocarpon Ait. Larvae feed undetected within the soil and cause damage to roots and underground vines. We correlated damage caused by feeding larvae from known BVW egg densities. Two cultivars of potted cranberry vines, ‘Stevens’ and ‘McFarlin’, were inoculated with 0, 5, 10, 20, 40, and 80 eggs per pot. Root damage and canopy health were assessed. ‘Stevens’ exceeded ‘McFarlin’ in dry shoot weight, total shoot length, total leaf area, and dry root weight before egg treatments. Damage to underground vines increased with increasing egg density and more damage was found in ‘Stevens’ than ‘McFarlin’ at the highest egg densities. In August, plant water use and total shoot length in ‘McFarlin’ were significantly greater in plants treated with 0–5 eggs per pot compared with plants treated with 40–80 eggs per pot. The effect on total shoot length was more pronounced in October. ‘Stevens’ showed no response to increasing BVW density for up to 24 weeks. Destructive measurements showed decreased root weight in ‘McFarlin’ but not ‘Stevens’. Both cultivars showed a similar decrease in dry shoot weight, total shoot length, and percent green leaf area with increasing BVW egg density. Root damage increased as BVW egg density increased and this damage resulted in reduced plant water use for ‘McFarlin’. Reduced shoot growth and leaf area was recorded for both cultivars, although these effects were more apparent in ‘McFarlin’ and at an earlier stage than in ‘Stevens’.
Effects of Distillation Time on the Pinus ponderosa Essential Oil Yield, Composition, and Antioxidant Activity
Authors: Zheljazkov Valtcho D. , Astatkie Tess , Schlegel Vicki
Published: February 2019

This study evaluated the effect of distillation time (DT; 1.25, 2.5, 5, 10, 20, 40, 80, 160, 240, and 360 min) on essential oil yield, composition, and the antioxidant activity of ponderosa pine essential oil. Pine essential oil yield increased with length of the DT and reached maximum at 160 min DT. The major oil constituents were alpha-pinene and beta-pinene, ranging from 17% to 40% and from 21% to 29%, respectively, of the total oil. Overall, the concentration of alpha-pinene and beta-pinene was high at the initial DT (5–20 min) and decreased with increasing DT. The concentration of myrcene (range, 0.9% to 1.5%) was lowest at 5 min DT, then increased at 10 min DT, and did not change with longer DT. Overall, the concentrations of most other constituents (delta-3-carene, limonene, cis-ocimene, alpha-terpinyl acetate, germacrene-D, alpha-muurolene, gamma-cadinene, delta-cadinene, and germacrene-D-4-ol) were low at the initial DT and increased with increasing DT. Total yields (a function of oil yield and the concentration of individual constituents) of all constituents were generally the lowest at 5 min DT, increased with increasing DT, and reached maximum at 160 min DT. The antioxidant capacity of the pine oil in this study varied between 7.0 and 14.5 μmole Trolox/g and was unaffected by DT. This study demonstrated that DT can significantly modify the essential oil yield and composition of ponderosa pine needles. Furthermore, DT could be used to obtain pine oil with targeted chemical profiles. This report can also be used as a reference point for comparing literature reports, in which different DTs are used to extract essential oil of ponderosa pine.
Introduction to Some Indigenous Vegetables in Japan
Authors: Fujime Yukihiro
Published: February 2019

Although Japan has a clear change of the seasons, the winter is mild, because it is surrounded by the sea. Even if it snows in the coastal area of the Japan Sea in the winter, it does not snow so heavily in the Pacific Ocean area. Because there is much rain in the summer and the air temperature and relative humidity are high, many horticultural crops are grown in the cool upland region, including the Hokkaido area. The Japanese islands are long from south to north covering north latitude 24° and 46°. Many indigenous vegetables such as water dropwort, japanese hornwort, wasabi, japanese butterbur, rakkyo, chinese chive, asatsuki, goldband lily, mioga ginger, and japanese pepper as well have been grown throughout ≈2000 years, being domesticated under selections and are now in modern Japan popular and important vegetables. Many variations have been produced under different climatic as well as soil conditions. Daikon, turnip, japanese bunching onion, komatsuna, kyona, taro, and eggplant have many variations in the growing areas. A lot of varieties are found particularly in daikon and turnip whose shape and color include small round, large round, long, and conical and white, green, and red, etc. Kyona and komatsuna belong to the same species, Brassica rapa, and also there are many useful variations as leaf vegetables in this species. Japanese bunching onion as an example has also many variations and in east Japan, the leaf sheaths are etiolated by hilling with soil during the winter and etiolated leaf sheaths are harvested in the spring, whereas in west Japan, the leaf sheaths are grown without hilling and green leaves are harvested. Those variations from indigenous vegetables are selected under every condition and various cultural methods were developed in growing areas. People have devised ways also how of cooking and using them depending on their eating habits as an established food culture.
Inheritance of the Easy-peeling Pellicle Trait of Japanese Chestnut Cultivar Porotan
Authors: Takada Norio , Nishio Sogo , Yamada Masahiko , Sawamura Yutaka , Sato Akihiko , Hirabayashi Toshio , Saito Toshihiro
Published: February 2019

‘Porotan’ is a Japanese chestnut cultivar (Castanea crenata Sieb. et Zucc.) that was selected from offspring of the cross 550-40 × ‘Tanzawa’ and released in 2006. Its nut is distinguished by a pellicle that is easy to peel after roasting; previously, all Japanese chestnut cultivars were thought to have a pellicle that was difficult to peel. Both 550-40 and ‘Tanzawa’ are Japanese chestnuts, and 550-40 is a selection descended from ‘Tanzawa’. Both 550-40 and ‘Tanzawa’ have a pellicle that is difficult to peel. Among 59 offspring of a cross of 550-40 × ‘Tanzawa’, 12 had an easy-peeling pellicle and 47 had a difficult-peeling pellicle; this ratio is not significantly different from the 1:3 expected ratio for monogenic inheritance based on a chi-square test at P = 0.05. A half-diallel cross without selfings was made among ‘Porotan’, ‘Tanzawa’, and ‘Tsukuba’. All the offspring from ‘Tanzawa’ × ‘Tsukuba’ and from ‘Tsukuba’ × ‘Porotan’ had a difficult-peeling pellicle; in contrast, 39 offspring from ‘Tanzawa’ × ‘Porotan’ segregated in a ratio of 19 difficult-peeling pellicle to 20 easy-peeling pellicle, which is not significantly different from the expected 1:1 ratio for monogenic segregation based on a chi-square test at P = 0.05. These results suggest that the easy-peeling pellicle trait of ‘Porotan’ is controlled by a major recessive gene at a single locus. We designated the pellicle peelability locus as P/p. According to this model, the ‘Tsukuba’ genotype is homozygous-dominant (PP), the ‘Tanzawa’ genotype is heterozygous (Pp), and the ‘Porotan’ genotype is homozygous-recessive (pp).
Effect of Plastic Mulch Type and Insecticide on Incidence of Tomato Spotted Wilt, Plant Growth, and Yield of Tomato
Authors: Andersen Peter C. , Olson Stephen M. , Momol M. Timur , Freeman Joshua H.
Published: February 2019

Tomato spotted wilt (TSW) is caused by a Tospovirus [tomato spotted wilt virus (TSVW)] and is vectored by thrips. TSW is a major impediment to tomato production worldwide and has been identified as the most significant limitation in the southeastern United States. The objectives of this study were to quantify the impact of polyethylene mulch type (black, metalized, Heat stripe, and Sonoco printed) and insecticide (alternating applications of spinosad and methamidophos) on midafternoon soil temperature under the mulch, reflected photosynthetic photon flux (PPF), vegetative growth, flower number, incidence of TSW, yield, and fruit quality of ‘FL-47’ tomato (Solanum lycopersicum L.). Midafternoon soil temperature during April and May (10-cm depth) averaged 2 to 4 °C higher under black mulch compared with the other mulches. The reflectance of PPF was highest for metalized mulch (up to two-thirds of PPF in full sunlight) followed by Heat stripe, Sonoco printed, and black mulch. In the presence of a full plant canopy, PPF reflectance was greatly reduced. The incidence of TSW [as determined visually and confirmed by enzyme-linked immunosorbent assay (ELISA)] was very high in 2002 and relatively low in 2003. Stem weight was significantly reduced in the black mulch treatment; however, plant height, leaf weight, or total numbers of flowers were not influenced by mulch type. For both years, the incidence of TSW on black mulch was significantly greater than that of the other mulch treatments for most sampling dates. The application of insecticides reduced percentage TSW on the last two sampling dates in both years. In 2002, but not 2003, yield per hectare was affected by mulch type. In both years, mulch type did not influence yield per plant and percentage marketable fruit, and insecticide applications increased yield per hectare, yield per plant, and percentage marketable fruit.
Ripening Development and Quality of Melting and Non-melting Flesh Peach Cultivars
Authors: Kao Ming-Wei S. , Brecht Jeffrey K. , Williamson Jeffrey G. , Huber Donald J.
Published: February 2019

Some physiological and biochemical properties of melting flesh (MF) and non-melting flesh (NMF) peaches [Prunus persica (L.) Batsch] were determined during ripening for 5 days at 20 °C. Respiration rates and ethylene production of MF ‘Flordaprince’, MF ‘TropicBeauty’, NMF ‘UFSun’, and NMF ‘Gulfking’ were measured at different harvest skin ground color-based maturity stages. The MF cultivars at harvest were mostly preclimacteric or at the onset of ripening. The NMF cultivars generally had higher ethylene production at harvest and throughout ripening than the MF cultivars; thus, the NMF fruit had started ripening on the tree before harvest. Some of the NMF fruit harvested at more advanced stages quickly became postclimacteric during the storage period. Quality determination after fruit ripening showed that MF ‘TropicBeauty’ had the highest soluble solids content (SSC), but also the highest titratable acidity (TA). The NMF cultivars had lower TA than the MF cultivars. NMF ‘Gulfking’ consistently had high SSC/TA, which was the result of it having the lowest TA. The NMF cultivars retained firmer texture than the MF cultivars during ripening. The flesh firmness of the NMF cultivars was four to five times greater than that of the MF cultivars. To investigate the reason for this significant textural difference, the activities of the cell wall modification enzymes pectin methylesterase (PME) and polygalacturonase (PG) were quantified in all four cultivars at advanced ripeness stages. PME activity appeared to be more directly related with peach fruit softening than PG activity.