bluuebunny/crossref_metadata_2025 huggingface dataset:
Cold Tolerance of Blueberry Genotypes Throughout the Dormant Period from Acclimation to Deacclimation
Authors: Rowland Lisa J. , Ogden Elizabeth L. , Ehlenfeldt Mark K. , Arora Rajeev
Published: February 2019

Cold hardiness in woody perennials is determined by complex interacting factors: the timing and rate of cold acclimation; the maximum level of cold tolerance attained; the maintenance of cold tolerance during the winter; and the rate of loss of cold tolerance or deacclimation on resumption of spring growth. For highbush blueberry, the degree of winter freezing tolerance and susceptibility to spring frosts have been identified as the most important genetic limitations of current cultivars. Depending on the winter and the location, both winter freezes and spring frosts can cause damage to floral buds or flowers resulting in substantial losses in yield. To identify genotypes that are particularly slow or late to deacclimate and thus may be useful in breeding for spring frost-tolerant cultivars, we compared deacclimation kinetics under controlled laboratory and field conditions among several blueberry genotypes with diverse genetic backgrounds. Clear genotypic differences in timing and rate of deacclimation were found. In the field study, the species Vaccinium constablaei Gray was identified as particularly late to deacclimate, and ‘Little Giant’ (50:50 hybrid of V. constablaei and V. ashei Reade) was nearly as late to deacclimate as 100% V. constablaei. Recently, we extended our cold tolerance measurements from October through midwinter comparing acclimation kinetics and maximum cold tolerance levels among genotypes. Although all genotypes appeared to reach maximum cold tolerance about mid-December under the study conditions, genotypic differences were detected in other aspects, including initial cold tolerance, rate of acclimation, maximum cold tolerance, and length of the plateau. ‘Little Giant’ and ‘Northsky’ (75:25 hybrid of V. corymbosum L. and V. angustifolium Ait.) were very early to acclimate and were hardier than the other genotypes both initially and when maximum cold tolerance was reached. Understanding how cold tolerance levels change throughout the dormant period should help us to develop cultivars better suited to their environments.
Evaluation of Cucurbita pepo Accessions for Crown Rot Resistance to Isolates of Phytophthora capsici
Authors: Padley Les D. , Kabelka Eileen A. , Roberts Pamela D. , French Ronald
Published: February 2019

Phytophthora capsici causes several disease syndromes on Cucurbita pepo L. (squash, pumpkin, and gourd), including crown rot, foliar blight, and fruit rot, which can lead up to 100% crop loss. Currently, there are no C. pepo cultivars resistant or tolerant to this pathogen, which can aid in disease management strategies. The objective of this study was to evaluate a select group of C. pepo accessions for resistance to the crown rot syndrome of P. capsici. One hundred fifteen C. pepo accessions, from 24 countries, were evaluated for their disease response to inoculation with a suspension of three highly virulent P. capsici isolates from Florida. Replications of each accession, including susceptible controls, were planted in the greenhouse using a randomized complete block design. At the second to third true leaf stage, each seedling was inoculated at their crown with a 5-mL P. capsici suspension of 2 × 104 zoospores/mL. Fourteen days after inoculation, the plants were visually rated on a scale ranging from 0 (no symptoms) to 5 (plant death). Mean disease rating scores (DRS) and sds were calculated for each accession and ranged from 1.3 to 5.0 and 0 to 2.0, respectively. Eight accessions with the lowest mean DRS were rescreened. Results paralleled those of the initial study with one accession, PI 181761, exhibiting the lowest mean DRS at 0.5. Further screening and selection of accessions from the C. pepo germplasm collection should aid in the development of breeding lines and cultivars with resistance to crown rot caused by P. capsici.
Injury on White Oak Seedlings from Herbicide Exposure Simulating Drift
Authors: Samtani Jayesh B. , Masiunas John B. , Appleby James E.
Published: February 2019

Herbicide drift to landscape and woodland trees is a particular concern in midwestern United States where the topography is relatively flat, large-scale agriculture relies on herbicides, and housing developments and woodlands are intermingled with agricultural fields. Recently, leaf abnormalities (called leaf tatters) have been reported on white oak (Quercus alba L.). We evaluated the effects of field corn herbicides on white oak at the swollen bud, leaf unfolding, and expanded leaf stages. Container-grown white oak seedlings were treated with 1%, 10%, and 25% standard field use rates of 2,4-D isooctyl ester, glyphosate, 2,4-D isooctyl ester + glyphosate, dicamba, acetochlor + atrazine, and metolachlor. Loss of interveinal tissues (leaf tatters) occurred after treatment with the chloroacetanilide herbicides, acetochlor (+ atrazine) and metolachlor, only when oaks were in the leaf unfolding stage. No other herbicide caused tatter-like symptoms. Dicamba and 2,4-D ester applied at the leaf unfolding stage caused leaf cupping, downward rolling of leaf margins, elongation of leaf tips, leaf strapping with parallel veination, and initial leaf cupping followed by death of the growing point. Glyphosate applied at either the leaf unfolding or expanded leaf stage caused leaf chlorosis and necrosis, leaf tip browning, and curling of leaves. Herbicide applications near white oak should be timed before leaf unfolding or after the expanded leaf stages.
Rooting and Overwintering Stem Cuttings of Stewartia pseudocamellia Maxim. Relevant to Hormone, Media, and Temperature
Authors: Nair Ajay , Zhang Donglin , Smagula John , Hu Dongyan
Published: February 2019

Stewartia pseudocamellia Maxim. (Japanese Stewartia), a member of Theaceae (tea family), is an excellent garden plant with ornamental features for all four seasons. Reproduction difficulty, however, limits its popularity. We conducted three experiments to ascertain the optimum conditions needed for rooting and subsequent overwintering of semihardwood Stewartia pseudocamellia cuttings. Cuttings were collected in July and prepared for rooting using two types of hormones (KIBA quick dip and Hormodin powder) and three media (Perlite + ProMix, Perlite + Perennial Mix, or Perlite + ProMix + Perennial Mix). Rooted cuttings were overwintered at four different temperatures. The best overwintering temperature was 5 °C, at which 65.6% of newly rooted cuttings survived. Temperatures lower than –12.2 °C were detrimental to the plants. Without cold treatment, only 21.9% of the rooted cuttings survived, which was three times lower than those that received 5 °C treatments. Plants rooted in Perlite + Perennial Mix had 61.8% overwintering survival, which is significantly higher than Perlite + ProMix. The quality of roots, indicated by total root length per cutting, was higher (104.3 cm) with Perlite + Perennial Mix, but not statistically significant. Cuttings treated with rooting hormones had higher rooting percentages (71.9% to 93.6%) as compared with the control (53%). For the same concentration (8000 mg·L−1), liquid (KIBA) and liquid + powder (KIBA + indole-3-butyric acid) rooting hormones resulted in better rooting percentages than powder (Hormodin) alone, although there was no statistical difference in rooting percentages among rooting hormone treatments. The best hormone for subsequent overwintering survival was the combination of quick dip (5000 mg·L−1 KIBA) and Hormodin #2 (0.3% a. i.; equivalent to 3000 mg·L−1). It resulted in 64.2% survival, significantly higher than for KIBA quick dip (8000 mg·L−1 a.i.) or Hormodin #3 (0.8% a. i.; equivalent to 8000 mg·L−1) alone. Our results suggest that reproduction (rooting and overwintering) of Stewartia was affected by many factors. We recommend rooting Stewartia in media that has good aeration and moderate water-holding capacity and overwintering them at ≈5 °C.
Therapeutic Influences of Plants in Hospital Rooms on Surgical Recovery
Authors: Park Seong-Hyun , Mattson Richard H.
Published: February 2019

Medical and psychological measurements of surgical patients were tested to determine the influence of plants and flowers within hospital rooms. Eighty female patients recovering from a thyroidectomy were randomly assigned to either control or plant rooms. Patients in the plant room viewed 12 foliage and flowering plants during their postoperative recovery periods. Data collected for each patient included length of hospitalization, analgesics used for postoperative pain control, vital signs, ratings of pain intensity, pain distress, anxiety and fatigue, the State-Trait Anxiety Inventory Form Y-1, the Environmental Assessment Scale, and the Patient's Room Satisfaction Questionnaire. Patients in hospital rooms with plants and flowers had significantly shorter hospitalizations, fewer intakes of analgesics, lower ratings of pain, anxiety, and fatigue, and more positive feelings and higher satisfaction about their rooms when compared with patients in the control group. Findings of this research suggest the therapeutic value of plants in the hospital environment as an effective complementary medicine for surgical patients.
Effects of Seed Moisture Content, Cooking Time, and Chamber Temperature on Nuña Bean (Phaseolus vulgaris L.) Popping
Authors: Vorwald Jesse , Nienhuis James
Published: February 2019

Nuña beans are a type of common bean (Phaseolus vulgaris L.) native to the Andean region of South America that possess the unusual property of popping; however, little is known regarding postharvest environmental effects on popping. Seed of a photoperiod-insensitive, temperate-adapted nuña bean breeding line, ‘PB24’, was produced at the Arlington Agricultural Research Station, Arlington, WI, and evaluated in a hot air popper. The experimental design was a factorial with three levels of popping time (60, 90, and 120 s), five levels of chamber temperature (101, 146, 208, 244, and 268 °C), and eight levels of seed moisture (2.5%, 3.2%, 5.2%, 6.6%, 8.3%, 12.0%, 15.3%, and 20%). Percentage of popped seed, sufficiently expanded to shed the seedcoat, was calculated. A curvilinear decrease in popping percentage was observed with increasing seed moisture content. In contrast, a curvilinear increase in popping percentage was observed with increasing chamber temperature and popping time. Larger mean squares were observed for main effects and first-order interactions associated with seed moisture content and chamber temperature compared with popping time. A combination of seed moisture below 5%, popping chamber temperature of 244 °C, and popping time of 90 s resulted in popping percentages greater than 90%.
Application of Two Microbial Teas Did Not Affect Collard or Spinach Yield
Authors: Knewtson Sharon J.B. , Griffin Jason J. , Carey Edward E.
Published: February 2019

Microbial tea from a commercial source and a homemade manure tea were evaluated for 2 years under organic and conventional fertility regimens. Testing with different fertility regimens allowed broader assessment of tea efficacy. Collard green (Brassica oleracea L. var. acephala cv. Top Bunch) yield and soil microbial activity were measured after microbial tea applications were made in three fertility treatments (conventional, organic, or no fertilizer amendment) on a previously unfertilized sandy loam soil. Spinach (Spinacia oleracea L. cv. Hellcat) and collard green yields were determined after commercial microbial tea application to a silt loam soil previously managed with organic or conventional vegetable crops in open fields and under high tunnels. Results indicated that nutrient additions influenced crop yields, even doubling yield. This demonstrated that improved nutrient availability would affect yield at the chosen locations. However, microbial tea applications did not affect crop yield. These results did not support the hypothesis that microbial tea improves plant nutrient uptake. Additionally, soil microbial respiration and biomass were unaffected after two or three tea applications.
Light-emitting Diodes for Manipulating the Phytochrome Apparatus
Authors: Stutte Gary W.
Published: February 2019

Light-emitting diodes (LEDs) are solid-state, long-lived, durable sources of narrow-band light output that can be used in a range of horticultural and photobiological applications. LED technology is rapidly developing and high-quality, high-output LEDs are becoming commercially available at an affordable cost. LEDs provide the opportunity to optimize the spectra for a given plant response, but consideration must be given to both photosynthetic and photomorphogenic effects of light while making those selections. A discussion of basic phytochrome response and data necessary to select narrow-band LEDs to achieve a specific photostationary state is provided. The use of LEDs to alter spectral quality, and phytochrome equilibrium, to regulate anthocyanin formation in red leaf lettuce and to regulate flowering of short-day strawberry are discussed.
Microenvironmental Variations within the High Tunnel
Authors: Wien Hans Christian
Published: February 2019

Simple unheated greenhouses covered with clear polyethylene, also known as high tunnels, in which plants are typically grown in the ground have become popular for extending the growing season for high-value horticultural crops. Although they are used principally to produce annual crops such as vegetables and cut flowers, increasing interest has focused on their use for perennial crops such as raspberries, blackberries, and ornamentals. Studies of temperature variation within the tunnel during the growing season have emphasized the rapid rise in air day temperature above ambient during the day and an equally rapid decrease at night. Spatial variation in temperature within the tunnel were much less marked, however, with air temperatures at the edge of a 10-m wide tunnel only ≈2 °C lower than in the center. For perennial crops, tunnel conditions during the off-season are also an important factor. In winter, air temperatures in the tunnel during sunny days rose above freezing even when ambient air temperatures stayed below freezing. Soil temperatures during the day and night fluctuated much less both inside and outside the tunnel and were significantly higher in the tunnel. Studies with nursery plants overwintered in similar structures indicate that spatial variation is again dwarfed by the overall air temperature fluctuation in these structures.
High Tunnel and Organic Horticulture: Compost, Food Safety, and Crop Quality
Authors: Millner Patricia , Reynolds Sara , Nou Xiangwu , Krizek Donald
Published: February 2019

High tunnels and protected horticultural structures provide organic and conventional growers with an economic means for extending the harvest season of fresh fruits and vegetables in a wide range of climate zones in North America and elsewhere. This report focuses on benefits associated with high tunnel production of fresh organic produce, including recent data on phytonutrient quality. In addition, this report discusses concerns and knowledge gaps associated with the use of composts and manures relative to food safety of fresh produce and survival of enteric pathogens in the moist, cool, reduced ultraviolet conditions often prevalent in high tunnels during cool-season production. The role of preplant and production elements of Good Agricultural Practices and Good Handling Practices applicable to high tunnel systems is provided.
Classification and Inheritance of Morphological and Agronomic Characteristics in Kentucky Bluegrass (Poa pratensis L.)
Authors: Shortell Robert R. , Meyer William A. , Bonos Stacy A.
Published: February 2019

The apomictic breeding behavior of Kentucky bluegrass (Poa pratensis L.) results in many unique cultivars. A classification system was previously developed to characterize the large number of Kentucky bluegrass cultivars into different types. However, many new cultivars have been released since the last refinement of the classification system. The objectives of this study were to determine differences in morphological and agronomic characteristics among select Kentucky bluegrass cultivars representing the major classification types and to determine broad-sense heritability estimates for important morphological (plant height, panicle length, flag leaf height, and flag leaf length and width) and agronomic (rhizome spread) traits in Kentucky bluegrass. A spaced-plant nursery trial was established in the spring of 2003 at Adelphia, NJ. One hundred seventy-three cultivars and selections were planted in a randomized complete block design with three replications. The morphological and agronomic traits listed were measured on spaced plants. High Density type cultivars (formerly the Aggressive type cultivars) had the most prostrate growth habit with plant heights of 33 and 43 cm in 2004 and 2005, respectively. Mid-Atlantic and Texas × Kentucky bluegrass hybrids had the widest rhizome spread (Mid-Atlantic = 73 and 121 cm; Texas × Kentucky bluegrass hybrids = 72 and 122 cm) in 2004 and 2005, respectively. Broad-sense heritability estimates were high for plant height (H = 0.84), panicle length (H = 0.88), flag leaf height (H = 0.85), and rhizome spread (H = 0.85); moderate for flag leaf length (H = 0.71); and low for flag leaf width (H = 0.11). This study characterizes new cultivars into respective groups and identifies the genetic inheritance of important morphological and agronomic traits in Kentucky bluegrass.
Rootstock Effects on Leaf Photosynthesis in ‘Navelina’ Trees Grown in Calcareous Soil
Authors: González-Mas M. Carmen , Llosa M. José , Quijano Antonio , Forner-Giner M. Angeles
Published: February 2019

Citrus crops in the Mediterranean region are often grown in high pH calcareous soils, which promote nutrient imbalances, especially iron deficiency. ‘Navelina’ trees grafted on eight different citrus rootstocks were assessed in terms of their relative tolerance to these soils. To do so, leaf gas exchange and chlorophyll a fluorescence parameters were measured for 2 consecutive years in leaves without visible injury symptoms. Trees were grown on the rootstocks Carrizo citrange, hybrids of Cleopatra mandarin × Poncirus trifoliata no. 5 (F-A 5), 13 (F-A 13), and 16 (030116), Troyer citrange × common mandarin no. 18 (F-A 418), King mandarin × P. trifoliata no. 7 (F-A 517), 020324 (Troyer citrange × Cleopatra mandarin), and Volkamer lemon × P. trifoliata no. 64 (230164). gS and transpiration rate were clearly lower in leaves of shoots grafted on Carrizo citrange than in those on the other rootstocks assayed, but net photosynthetic flux did not differ. However, leaves of shoots on Carrizo citrange displayed a decline in their maximum quantum yield of PSII photochemistry [variable fluorescence/maximum fluorescence (Fv/Fm) ratio] and other chlorophyll parameters in the steady state such as photochemical quenching (qP) and the quantum efficiency of PSII photochemistry (ΦPSII) as well as an increase in nonphotochemical quenching (qN). Other rootstocks such as 030116, F-A 517 and, especially, F-A 5 showed the highest ΦPSII and Fv/Fm values, whereas F-A 5 had the lowest qN in the steady state. The photosynthetic characteristics observed in leaves on Carrizo citrange showed them to be the least tolerant to these calcareous conditions, whereas photosynthesis of ‘Navelina’ trees budded on F-A 5 were the most tolerant.
Broad-sense Heritability and Stability Analysis of Brown Patch Resistance in Tall Fescue
Authors: Bokmeyer Jonathan M. , Bonos Stacy A. , Meyer William A.
Published: February 2019

Brown patch, caused by Rhizoctonia solani Kühn, is a devastating disease of tall fescue (Festuca arundinacea Schreb.). Developing genetic resistance is a viable long-term control strategy; however, the genetic mechanism of brown patch resistance in tall fescue is not known. The objectives of this study were to determine the broad-sense heritability and stability analysis of brown patch resistance in tall fescue. To complete these objectives, 230 tall fescue genotypes were arranged in a randomized complete block design with six clonal replications at two locations and evaluated for brown patch resistance over 2 years. Two isolates of R. solani were used to inoculate both field trials at a rate of 0.8 g·m−2 of prepared inoculum. The lack of complete resistance and the observation of a continuous distribution of phenotypes suggest that brown patch resistance is quantitatively inherited. The broad-sense heritability estimates (0.25 on a single plant basis and 0.74 on 12-plant clonal mean basis) indicate that resistance is influenced by the genotype and also illustrate the importance of replication in selecting for brown patch resistance in tall fescue. Stability analysis resulted in the identification of tall fescue genotypes that were stable over multiple environments for brown patch resistance.
Variation in Low-temperature Exotherms of Pecan Cultivar Dormant Twigs
Authors: Volk Gayle M. , Waddell John , Towill Leigh , Grauke L.J.
Published: February 2019

Pecan [Carya illinoinensis (Wangenh.) K. Koch] trees native to northern regions are more cold-tolerant than those native to and grown in the southern United States. To identify a possible assay for cold hardiness, dormant winter twigs from 112 diverse pecan cultivars grown in Texas were surveyed using differential thermal analyses (DTA). The low temperature exotherm (LTE) from DTA was identifiable when twigs were stored at –3 °C for up to 120 d after harvest. Thirty-nine percent of the southern pecan cultivars lacked an obvious LTE, and the remaining southern cultivars had an average LTE of –32.9 °C. In contrast, only 11% of the northern pecan cultivars lacked the LTE and the remaining cultivars had a significantly lower LTE of –35.4 °C. Because twig samples were collected from trees grown in the same Texas orchard, it is suggested that there is a genetic component that affects the temperature of the LTE. Budbreak generally occurred earlier in southern cultivars than those that originated in the north. Both budbreak and LTE data can be correlated with regional origin; timing of budbreak may be preferred over DTA to predict relative cold hardiness in pecan.
Competition Between Vegetative and Reproductive Growth in Cranberry
Authors: Vanden Heuvel Justine E. , DeMoranville Carolyn J.
Published: February 2019

Competition between reproductive and vegetative growth has not been studied in cranberry. The objective of this research was to assess the growth patterns of leaves and fruit in three cranberry cultivars to determine whether vegetative and reproductive growth compete for resources. ‘Stevens’, ‘Howes’, and ‘Early Black’ uprights and fruit were collected on a weekly basis in 2002 and on a biweekly basis in 2003 and 2004 from a research bog in Massachusetts. Although growth was affected by cultivar and year, data indicated a general shifting of resource allocation from leaf area and dry weight accumulation to fruit growth at ≈1500 growing degree days (GDD, base 4.4 °C), when the initial surge of fruit growth began. Leaf area and dry weight accumulation resumed at ≈2300 GDD, resulting in a competition for resources with the developing fruit until after 3000 GDD. A lag phase in fruit diameter and dry weight accumulation was noted in some years and some cultivars and may be partially the result of the resumption of leaf growth at 2300 GDD. Fruit and shoot growth appear to compete for resources in late July through early August in Massachusetts, when carbohydrate concentration of uprights and roots is extremely low.
Modeling Seasonal Dynamics of Canopy and Fruit Growth in Grapevine for Application in Trellis Tension Monitoring
Authors: Tarara Julie M. , Blom Paul E. , Shafii Bahman , Price William J. , Olmstead Mercy A.
Published: February 2019

Estimates of canopy and fruit fresh mass are useful for more accurate interpretation of data from the Trellis Tension Monitor, a tool for real-time monitoring of plant growth and predicting yield in trellised crops. In grapevines (Vitis labruscana Bailey), measurements of shoot and fruit fresh mass were collected at frequent intervals (14 to 21 days) over 5 years, and these data were correlated with variables that could be obtained nondestructively: shoot length, number of leaves per shoot, and number of clusters per shoot. Shoot length provided a good estimator of shoot fresh mass in all years. Nonlinear logistic regression models described the dynamics of canopy growth from bloom to the early stages of ripening, which often is poorly represented by simple linear regression approaches to seasonal data. A generalized function indicated a lower bound of ≈600 degree-days, after which an increase in shoot fresh mass could be considered on average to contribute only slightly to further increases in trellis wire tension. The dynamics of fruit mass were captured adequately by a nonlinear function, but not as well as vegetative mass because of larger variances in fruit mass. The number of clusters per shoot was associated with fruit mass only after the accumulation of ≈550 degree-days or, equivalently, the time at which fruit mass exceeded ≈25 g per shoot. Seasonal dynamics of the ratio of fruit to vegetative fresh mass were not sufficiently discernable by the logistic models because of the dominance of fruit mass and its large interannual variation.
Naphthaleneacetic Acid Reduces Leader Growth of Fraser Fir Christmas Trees
Authors: Rutledge M. Elizabeth , Frampton John , Blank Gary , Hinesley L. Eric
Published: February 2019

Two methods of application, the Danish Easy Roller and the German Sprühsystem, were tested to evaluate the effectiveness of naphthaleneacetic acid (NAA) at reducing leader growth (tips of primary axes) of fraser fir [Abies fraseri (Pursh) Poir.] Christmas trees. A commercial product, Sucker-Stopper RTU (1.15% ethyl 1-NAA), was applied to leaders at concentrations of 0 to 500 mL·L−1 when leaders were 8 to 15 cm long. As the concentration increased, leader elongation decreased. The Easy Roller reduced leader growth the most, but leader mortality was unacceptable at concentrations 20 mL·L−1 or greater. Although less effective than the Easy Roller, the Sprühsystem caused negligible mortality of leaders. Applying 40 mL·L−1 with the Easy Roller yielded ≈50% of leaders with target lengths of 20 to 36 cm with little mortality. The Sprühsystem gave similar results at 250 mL·L−1. NAA might be useful for producing dense trees with minimal shearing or for producing more natural, open trees during shorter rotations.
Seed Meals from Brassicaceae Oilseed Crops as Soil Amendments: Influence on Carrot Growth, Microbial Biomass Nitrogen, and Nitrogen Mineralization
Authors: Snyder André , Morra Matthew J. , Johnson-Maynard Jodi , Thill Donald C.
Published: February 2019

Brassicaceae seed meals (BSMs) average 6% nitrogen (N) by weight and contain glucosinolates (GLSs) that produce biologically active compounds. A two-season field study was initiated to determine how Brassica juncea L., Brassica napus L., and Sinapis alba L. seed meals, each with different glucosinolate profiles, alter carrot (Daucus carota L. subsp. sativus) growth, microbial biomass N (MBN), and soil N mineralization. BSM applications of 1 and 2 t·ha−1 36 days before planting did not influence carrot emergence, whereas carrot emergence decreased up to 40% in S. alba treatments seeded 15 days after BSM application. Crop quality was unaffected by BSM treatments and total fresh market yields were equal to or higher than the unamended controls in both years. At 4 and 8 days after seed meal application, MBN in the high-GLS B. juncea and S. alba treatments was 48% to 67% lower than in the low-GLS B. napus treatment. Seasonal apparent net N mineralized expressed as a percentage of the total N applied in the seed meals was unaffected by glucosinolate concentration and ranged from 30% to 81% across both years. BSMs can be used to increase soil inorganic N and carrot yields, but crop phytotoxicity is possible depending on the meal and its respective glucosinolate content. GLS degradation products inhibit microbial N uptake in the short term, but longer-term N availability is not compromised.
Genetic Diversity of Chinese Bayberry (Myrica rubra Sieb. et Zucc.) Accessions Revealed by Amplified Fragment Length Polymorphism
Authors: Zhang Shuiming , Gao Zhongshan , Xu Changjie , Chen Kunsong , Wang Guoyun , Zheng Jintu , Lu Ting
Published: February 2019

Amplified fragment length polymorphism (AFLP) was used to analyze genetic diversity of 100 accessions of Chinese bayberry (Myrica rubra Sieb. et Zucc.), one of the widely cultivated fruit tree crops in southern China. Six E-NN/M-NNN primer combinations were selected and a total of 236 bands were obtained, of which 177 were polymorphic (75.01%). An unweighted pair-group method of the arithmetic averages (UPGMA) was used to analyze the genetic relationships. The Dice's similarity coefficient among the Chinese bayberry accessions ranged from 0.75 to 1.00 and was 0.49 between Chinese bayberry and wax myrtle (M. cerifera L.). The 100 accessions of Chinese bayberry were clustered into two groups and seven subgroups. Subgrouping of Chinese bayberry was not related to the sex of the plant and color or size of the ripe fruit, but to some extent the region where the accession originated. However, the accessions from the same region did not necessarily belong to the same group or subgroup, which suggested the presence of extensive gene flow among different regions. Furthermore, close relationships between some morphologically similar accessions were found.
Effect of Cultivar and Growing Location on the Mineral Composition of Canola Sprouts
Authors: Bhardwaj Harbans L. , Hamama Anwar A.
Published: February 2019

Sprouts from seeds of cruciferous plants, such as brussels sprouts, broccoli, and cauliflower (Brassica sp.) are considered desirable for human diets. However, no information is available about sprouts made from seeds of canola (Brassica napus L.), a cruciferous crop that is increasing in acreage in the United States and is considered a source of healthful, edible oil. This study reports contents of aluminum (Al), boron (B), calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), phosphorus (P), sulfur (S), and zinc (Zn) in sprouts made from seeds of four canola cultivars (Banjo, KS 8200, KS 8227, and Virginia) grown at three locations (Orange, Petersburg, and Suffolk) in Virginia during two crop seasons (2001–02 and 2002–03). The contents of protein, oil, P, K, Ca, Mg, S, and Na (expressed as percent on a dry weight basis) in canola sprouts were 27.33, 25.1, 0.61, 0.43, 0.43, 0.31, 0.57, and 0.01, respectively. The contents of B, Cu, Fe, Mn, and Zn (expressed as mg·kg−1) in canola sprouts were 12.35, 5.69, 88.46, 45.44, and 48.98, respectively. Contents of various minerals in canola sprouts were greater than those in sprouts of alfalfa, brussels sprouts, mungbean, and radish reported in the literature. It was concluded that canola sprouts are a potential component of diets for superior human nutrition.
Timed Release of Flurprimidol from a Granular Formulation in Mulches and Sand
Authors: Grey Timothy L. , Czarnota Mark , Potter Thomas , Bunnell B. Todd
Published: February 2019

Flurprimidol is a plant growth regulator that can be applied as a granular formulation. Understanding flurprimidol release from a granular formulation and movement in various mediums will impact how it is used. Dissipation of flurprimidol from a granular formulation and movement through organic media and sand were evaluated in a greenhouse and laboratory experiment. Experimental variables included media type, depth, and irrigation event. Dissipation isotherms were determined by applying nonlinear regression. Mobility was evaluated using columns filled with media, which was surface-spiked with the granular formulation and then irrigated once daily for 22 consecutive days. Leachate was collected and analyzed by high-performance liquid chromatography–mass spectroscopy. Half-life (DT50), defined as time to 50% reduction, varied among sand, media, and media depth. Flurprimidol dissipation was rapid through sand with DT50 of 6 days. DT50 increased with increasing media depth from 5 to 10 cm for pine bark plus sand, 18 and 35 days, and hardwood bark plus sand, 77 and 173 days, respectively. Maximum flurprimidol leaching was a cumulative 71% of applied amounts over 22 irrigation events through the sand. Hardwood and pine bark media allowed less than 25% of flurprimidol to escape through the column. Data for all media indicated that flurprimidol was mobile through the substrates but exhibited hysteresis with pine bark and hard wood bark media. An initial pulse of flurprimidol will release slowly from this formulation over time. These results indicate that flurprimidol will dissipate from a granular formulation over time and that it will have movement through sand soil and pine bark and hardwood bark media to reach the roots of growing plants.
Estimation of Chilling and Heat Requirements of Some Persian Walnut Cultivars and Genotypes
Authors: Aslamarz Asadolah Aslani , Vahdati Kourosh , Rahemi Majid , Hassani Darab
Published: February 2019

The objective of this work was to determine the chilling and heat requirements of Persian walnut cultivars and genotypes using excised twigs. The experiment was carried out from Nov. 2006 and 2007 to Mar. 2007 and 2008. One-year-old twigs were prepared from four cultivars and four domestic genotypes of Juglans regia L. After leaf fall, the twigs were taken and placed in plastic bags and kept at 4 ± 1 °C to stimulate 400 to 1500 chilling hours. After chilling, the excised twigs were transferred to the greenhouse with a natural photoperiod and a temperature from 18 to 27 °C. The evaluation of budbreak was made three times a week and the number of accumulated growing degree hours (°C) was determined until the buds reached the balloon or green tip stage. The chilling requirements were lowest (400 h) for catkins and highest (1000 h) for lateral buds. The Serr cultivar and ‘Z30’ genotype had the lowest chilling requirements (650 and 650 h). ‘Lara’, ‘Z63’, ‘Z53’, ‘Pedro’, and ‘Z67’ showed intermediate chilling requirements with values of 900, 900, 800, 750, and 750 h, respectively. Finally, ‘Hartley’ completed its dormancy after an accumulation of 1000 h, being the walnut cultivar with the highest chilling requirement in our study. As the final result, the cultivars and genotypes were classified into three groups based on their heat requirements: low requirement (‘Z30’ and ‘Serr’), medium requirement (‘Z53’, ‘Z67’, ‘Lara’, and ‘Pedro’), and high requirement (‘Hartley’ and ‘Z63’).
Growth and Photosynthetic Capability of Momordica grosvenori Plantlets Grown Photoautotrophically in Response to Light Intensity
Authors: Zhang Meijun , Zhao Duanduan , Ma Zengqiang , Li Xuedong , Xiao Yulan
Published: February 2019

Momordica grosvenori plantlets were cultured in vitro for 26 d on sucrose- and hormone-free Murashige and Skoog (MS) medium with four levels of photosynthetic photon flux density (PPFD), namely 25, 50, 100, or 200 μmol·m−2·s−1, and a CO2 concentration of 1000 μmol·mol−1 in the culture room [i.e., photoautotrophic micropropagation (PA) treatments]. The control treatment was a photomixotrophic culture using MS medium containing sucrose and NAA with a CO2 concentration of 400 μmol·mol−1 in the culture room and a PPFD of 25 μmol·m−2·s−1. Based on the results, a second experiment was conducted to investigate the effects of α-naphthaleneacetic acid (NAA) and sucrose on callus formation. For this, plantlets were grown in the absence and presence of either NAA or sucrose. Compared with the control, the PA plantlet had a well-developed rooting system, better shoot, greater chlorophyll content, and higher electron transport rate and the ex vitro survival percentage was increased by 31%. Both sucrose and NAA stimulated callus formation on the shoot bases of control plantlets, whereas calluses did not form on the plantlets grown in sucrose- and hormone-free medium. The stronger light intensities increased the fresh and dry weight of plantlets. A PPFD of 100 μmol·m−2·s−1 was more suitable for the growth of M. grosvenori plantlets. Therefore, photoautotrophic plantlets grown at high light intensities would be better suited to the intense irradiance found in sunlight.
The Effect of Physical and Hydraulic Properties of Peatmoss and Pumice on Douglas Fir Bark Based Soilless Substrates
Authors: Gabriel Magdalena Zazirska , Altland James E. , Owen James S.
Published: February 2019

Douglas fir [Pseudotsuga menziesii Mirb. (Franco)] bark (DFB), sphagnum peatmoss, and pumice are the most common substrate components used in the Oregon nursery industry. The objective of this study was to document the effect of peat and pumice addition on the physical and hydrological properties of DFB soilless substrates. A secondary objective was to determine if measured properties of mixed soilless substrates can be accurately predicted from the known properties of the individual components. Treatment design was a 3 × 3 factorial with three rates each of sphagnum peatmoss and pumice (0%, 15%, and 30% by vol.) added to DFB. The resulting nine substrates were measured for total porosity, air space, container capacity, and bulk density using porometers. Moisture characteristic curves were generated by measuring water content along a continuous column. Adding pumice to DFB decreased total porosity, container capacity, available water, and water-buffering capacity but increased bulk density. Adding peatmoss to DFB increased total porosity, container capacity, and available water but decreased air space and bulk density. Comparison of predicted values against measured values indicated that bulk density could be predicted reliably; however, all other physical properties could not be accurately predicted.
Evaluation of a Cider Apple Germplasm Collection of Local Cultivars from Spain for Resistance to Fire Blight (Erwinia amylovora) Using a Combination of Inoculation Assays on Leaves and Shoots
Authors: Martínez-Bilbao Alejandro , Ortiz-Barredo Amaya , Montesinos Emilio , Murillo Jesús
Published: February 2019

Fire blight, caused by the bacterium Erwinia amylovora, is among the three most important diseases of apple. A major effective method for its integrated management is the reduction of the susceptibility of the host. Cider apple production in Spain is based on local apple cultivars with minimum crop management and phytosanitary control. After the entry of fire blight in Spain, the selection and planting of cultivars with low susceptibility to this disease has thus become of paramount importance. In consequence, and as part of a wider characterization effort, we undertook the evaluation of an apple germplasm collection of local apple cultivars from Spain for susceptibility to fire blight. Because of the quarantine status of E. amylovora in Europe, we evaluated the use of a detached leaf inoculation assay in combination with a traditional shoot inoculation assay to reduce the amount of plant material to evaluate and to minimize pathogen manipulation. Comparison of the susceptibility values for 78 apple cultivars indicated a low but significant correlation (r = 0.56; α = 0.01) between the leaf and shoot inoculation methods. Although the detached leaf assay was not reliable for the direct selection of cultivars with low susceptibility, it was useful to optimize resources and limit the potential dispersal of the pathogen by allowing the exclusion of medium and highly susceptible cultivars from further evaluation. Shoot inoculation of 103 apple cultivars allowed the identification of 48 cultivars with high levels of resistance to fire blight, which could serve as starting material both for apple production and for breeding programs.
Growth and Flowering of Petunia and Impatiens: Effects of Competition and Reduced Water Content Within a Container
Authors: Blanusa Tijana , Vysini Eleni , Cameron Ross W.F.
Published: February 2019

The primary objective of this research was to determine how the presence of more than one plant and more than one species in a container influence plant quality, particularly when the volume of water given to the container is reduced. Petunia ×hybrida ‘Hurrah White’ and Impatiens ‘Cajun Violet’ were chosen as typical bedding plant species. Plants were grown in 2 l containers either under “100% ETp” (i.e., replacing all the water lost by evapotranspiration in the previous 24 h) or under a moisture-restrictive regime of “25% ETp,” in which plants received 25% of the “100% ETp” value. An ancillary experiment investigated whether low watering resulted in floral buds being aborted. Results demonstrated that watering requirements of Petunia under “100% ETp” (i.e., replacing all the water lost by evapotranspiration in the previous 24 h) were on average 30% greater than those of Impatiens. However, when two Petunia plants were growing in the same container, the volume of water required to maintain soil moisture content at container capacity was on average only 10% greater than for a single plant. Under a “25% ETp” regime in which plants received 25% of the “100% ETp” value, flower number, plant height, and flower size were reduced by 50%, 33%, and 13%, respectively, in Petunia compared with “100% ETp.” For example, flower numbers decreased from an average of 71 to 33 flowers per plant in “100% ETp” and “25% ETp,” respectively. Petunia plants in the “25% ETp” regime, however, were more efficient at producing both biomass and flowers in relation to the volume of water applied. Petunia plants that experienced both competition from other plants in the container and lower irrigation rates had enhanced efficiency of flower production (i.e., more flowers per unit biomass). For Impatiens, however, the growing of single plants at “25% ETp” was plausible, but the addition of a Petunia plant at “25% ETp” was detrimental to plant quality (Impatiens flower numbers reduced by 75%).
Potential of Methyl Jasmonate as a Harvest Aid for ‘Thompson Seedless’ Grapes: Concentration and Time Needed for Consistent Berry Loosening
Authors: González-Herranz Raquel , Cathline Kimberley A. , Fidelibus Matthew W. , Burns Jacqueline K.
Published: February 2019

The application of methyl jasmonate (MeJA) to grapes (Vitis vinifera L.) may decrease fruit detachment force (FDF) and promote the development of dry stem scars on the berries, both of which could improve the quality of machine-harvested raisin grapes. However, treatment with MeJA also promotes preharvest fruit drop, which is undesirable. Thus, experiments were conducted to determine how the concentration of MeJA applied and time after treatment affect FDF and abscission of grapes. Mature ‘Thompson Seedless’ grapevines were treated with one of five different solutions containing 0, 0.2, 2, 10, or 20 mm MeJA, and FDF and fruit abscission were monitored for ≈2 weeks. Treatment with 2 mm or less MeJA had inconsistent effects on FDF and did not promote abscission, whereas treatment with 10 to 20 mm MeJA reduced FDF within 2 to 3 days after treatment (DAT) and promoted abscission, which began on ≈3 DAT and persisted for ≈8 DAT. Thus, to optimize the use of MeJA as a harvest aid for ‘Thompson Seedless’ may require application of between 2 and 10 mm MeJA followed by harvest within 3 DAT.
Seed Development in Lesquerella fendleri (L.)
Authors: Chen Grace Q. , Vang Louisa , Lin Jiann-Tsyh
Published: February 2019

The morphological, physiological, and biochemical changes during seed development of Lesquerella fendleri were investigated from 7 days after pollination (DAP) to desiccation. The entire course of seed development lasted ≈49 days and it can be divided into seven sequential stages (I to VII). During the early stages (I to III, 7 to 21 DAP), seed grew rapidly, showing a dramatic increase in size and fresh weight. They contained ≈75% water. During midmaturation stages (IV to V, 28 to 35 DAP), storage lipids, proteins, and other components of dry weights accumulated at maximum rates. The accumulation curves followed a sigmoidal pattern during seed development. As a result of water loss, fresh weight dropped significantly when seed progressed to late-maturation/desiccation stages (VI to VII, 42 to 49 DAP). The size of the seed decreased slightly and the color changed from green to orange–brown. Seed proteins were also analyzed using SDS-PAGE. Proteins with high molecular weights were prominent in developing seed at early stages (I to III). At Stage IV (28 DAP), proteins with low molecular weight appeared, whereas the high-molecular-weight proteins decreased in proportion. These low-molecular-weight proteins became predominant throughout the remaining stages of seed development. Forty-seven percent of freshly harvested seed at 35 DAP were able to germinate after 7 days incubation. The germination percentage increased to a maximum of 95% at 42 DAP after 7 days incubation. The relationships among seed morphology, reserve synthesis, and germination are discussed.
A Convenient Method for Exposing Shoot Apical Meristems Using Compressed Air
Authors: Suzue Hisanao , Hosokawa Munetaka , Yazawa Susumu
Published: February 2019

Exposing the shoot apical meristem (SAM) is necessary in horticultural practices such as shoot tip culture, colchicine treatment, gene transfer, and so on. However, ordinary methods of exposing SAMs require extensive training and are labor-intensive. We developed equipment to expose SAMs quickly and easily by blowing compressed air on the shoot tips. Using this equipment allowed SAMs to be exposed more rapidly than the ordinary methods. Exposure time was shortened from 27.8 s to 7.4 s, 15.7 s to 7.9 s, and 59.7 s to 6.8 s in chrysanthemum (Chrysanthemum morifolium), dahlia (Dahlia spp.), and Lilium leichtlinii, respectively. To determine whether blowing compressed air caused injury to SAMs, we used shoots in which the SAMs had been already exposed and observed resin sections of SAMs that had been subjected to the additional compressed air treatment for several seconds. Results showed that blowing additional compressed air for as long as 9 s did not injure SAMs. Using this equipment, we can expose SAMs without using a stereomicroscope by blowing compressed air to the top of shoots for several seconds. Over 70% of SAMs could be exposed in a 7- to 13-s blowing treatment without injury. We could successfully use this equipment in shoot tip culture and leaf primordia-free SAM culture.
The Effects of Surfactants, Nozzle Types, Spray Volumes, and Simulated Rain on 1-Methylcyclopropene Efficacy on Tomato Plants
Authors: MacKinnon Daniel K. , Shaner Dale , Nissen Scott , Westra Phil
Published: February 2019

A study was conducted with a wettable powder formulation of 1-methylcyclopropene (1-MCP) to determine the effects of surfactants, spray volume, nozzle type, and rain fastness on the efficacy of 1-MCP to protect tomato plants from the epinastic effects of ethephon. 1-MCP at 25 and 50 g·ha−1 protected tomato plants from 250 and 500 g·ha−1 of ethephon. Of the three best surfactants tested, two (Dyne-Amic and Silwet L-77) contained silicone and one (Herbimax) an emulsified petroleum oil. The efficacy of 1-MCP increased with an increase in spray volume from 150 L·ha−1 to 400 L·ha−1, suggesting that an increase in leaf coverage leads to greater protection and that the translocation of 1-MCP is limited within tomato plants. There was no significant effect of spray nozzle type on 1-MCP activity. 1-MCP appeared to be rainfast within 15 min after application.