bluuebunny/crossref_metadata_2025 huggingface dataset:
The Relationship of Knowledge, Attitudes, and Perceptions Regarding Non-native Texas Invasive Plant Species
Authors: Frey Sharon , Robinson Carolyn
Published: February 2019

Plants have been introduced into the United States intentionally as well as unintentionally as seeds and weeds. Technological advances, a mobile society, and our curiosity and desire to improve our landscapes have led to an ever-increasing invasive movement. These alien plants can jeopardize native populations, alter ecosystems, alter fire and water regimes, change the nutrient status, modify habitats, and cause significant economic harm. Today's public is unaware of the danger some non-native plants species pose to natural areas, thereby contributing to the lack of control for non-native invasive plants. This study looked at the knowledge and attitudes of Texas Master Gardeners as related to invasive species commonly used in landscaping. A web survey was made available to all Texas Master Gardeners that included pictures of plants along with their common and scientific names. Participants were asked to identify which they thought were invasive and contribute information regarding their knowledge of non-native invasive plants. Each of the invasive plants shown is on both the federal and the Texas Invasive Plant lists. Inquires were made concerning the occurrence of these plants in the participants' personal landscape and communities and their perceptions of each plant as an invasive threat. The purpose of the study is to determine if a relationship exists between knowledge, attitudes and perceptions of the participant and the occurrence of non-native invasive plants in the landscape. The results of this study will help determine factors that contribute to the lack of control for non-native invasive plants.
Light, Fertilizer, and CO2 Interact in Petunia ×hybrida Nutrient Uptake and Partitioning
Authors: Frantz Jonathan , Ling Peter
Published: February 2019

Bedding plant petunia (Petunia ×hybrida) is often produced with high nutrient concentrations as a cool-season crop. How a plant uses the nutrients supplied will depend in large part on the environmental factors influencing growth rate, such as light and CO2. Since more growers are considering using supplemental CO2 to improve energy efficiency for plant production, it is important to understand light and fertilizer levels needed for efficient production of high-quality plants. Using a multi-chamber controlled environment system, petunia plants were grown from seed for 6–8 weeks after transplanting into different light and CO2 environments and fed with either a low (7.1 mM N) or high (21.3 mM N) fertilizer regime. Plants were evaluated for appearance, harvested periodically, and separated into flower, stem, and leaf biomass. Biomass was then dried and analyzed with ICP-OES for essential macro- and micronutrients. Low-fertilizer-grown plants had consistently earlier and more flowers, but showed symptoms of nutrient deficiencies in the final few weeks of production at all light and CO2 levels. There were significant interactions between light and fertilizer treatments for different nutrients. Calcium uptake was greatly influenced by light level, Fe, P, and K were influenced by the fertilizer supply, and Mg and B were inversely influenced by fertilizer supply at high light. These data suggest new management strategies are needed to improve fertilizer use efficiency in different environments.
Impact of Low Iron and Phosphorus Stresses on Acidification of Nutrient Solution by Geranium
Authors: Taylor Matthew D. , Nelson Paul V. , Frantz Jonathan M.
Published: February 2019

The cause of sudden substrate pH decline by geranium is unknown. Low Fe and low P have been shown to cause many plant species to acidify the substrate. Research was done to determine if low Fe or P stresses caused four geranium (Pelargonium ×hortorum Bailey) cultivars to acidify nutrient solution. Two cultivars were susceptible and two resistant to substrate acidification based on a grower survey. Rooted geranium cuttings were transferred to 4-L containers containing modified Hoagland's solution with N supplied as 15% NH4 and 85% NO3. The plants were grown in a greenhouse for 44 days. Treatments consisted of a complete nutrient solution and two similar solutions devoid of either Fe or P. Solutions pH was set at 5.8, changed weekly, and tested 3 and 6 days after each change. Because all cultivars showed similar responses, results were combined. Twenty days after transplanting (DAT), plants in all treatments, including control, caused solution pH to fall below 5. At 37 DAT, the solution pH levels for control, minus Fe, and minus P treatments were 4.1, 3.7, and 3.6, respectively. Results indicated that geranium is an acidifying plant when N is supplied as 15% NH4 and 85% NO3. Additionally, low Fe and low P stresses increase the acidification rate. Total dry weights of minus-P plants were about half that of minus-Fe plants. This indicated that plants under P stress had a higher specific rate of acidification than plants under Fe stress.
Pre-emergence Weed Control in No-tillage Pumpkin Production
Authors: Walters S. Alan , Young Bryan G. , Krausz Ronald F.
Published: February 2019

A field study was conducted in 2002, 2003, and 2004 to evaluate various pre-emergence herbicides (ethafluralin & clomazone, ethafluralin & clomazone + halosulfuron, and ethafluralin & clomazone + imazamox) with or without a winter rye (Secale cereale L.) cover crop in tillage and no-tillage `Appalachian' pumpkin (Cucurbita pepo L.) production. All herbicides were applied within two days of seeding, and no injury was observed with any of the herbicides evaluated at any time during the three growing seasons. Early- and late-season control of all weed species [giant foxtail (Setaria faberi Herrm.), common cocklebur (Xanthium strumarium L.), redroot pigweed (Amaranthus retroflexus L.), and common waterhemp (Amaranthus rudis Sauer)] were highly correlated (0.47 ≤ r ≥ 0.86, P ≤ 0.01) with pumpkin yield and fruit size. The winter rye + no-tillage system provided greater weed control compared to the tillage systems and the no cover crop + no-tillage production system. Although winter rye alone had little influence on pumpkin yield, the no-tillage system improved pumpkin yield and fruit size compared to the tillage system. The two herbicide combinations (ethafluralin & clomazone + halosulfuron and ethafluralin & clomazone + imazamox) improved weed control and pumpkin yields compared to only ethafluralin & clomazone. Although this study indicated that the use of a high-residue winter rye cover crop in no-tillage pumpkin production will provide some weed control, the choice of pre-emergence herbicides is critical to maximize pumpkin productivity. No-tillage pumpkin production is feasible with proper herbicide use and timing, although current herbicide options will not provide optimal weed control.
Optimization of the RAPD Marker Techniques in Camellia
Authors: Chen Lianghong , Nelson Mack
Published: February 2019

Randomly amplified polymorphic DNA (RAPD) technique is based on DNA amplification by polymerase chain reaction (PCR) of random DNA segments using single arbitrary nucleotide sequences. It has been widely used for genetic mapping, plant and animal breeding programs, and DNA fingerprinting. However, there is no single set of RAPD-PCR conditions that can be applied to all situations. In order to adjust reaction component concentrations within suggested ranges for efficient amplification during the use of RAPD in detection of genetic variation of genus Camellia, crucial factors, such as concentrations of MgCl2 and DNA, annealing temperature (37 to 44 °C), and the use of an AmpliTaq® DNA polymerase and Stoffel fragment were examined. Five camellia cultivars, `Winter's Beauty', `Pink Icicle', `Polar Ice', `Winter's Hope', and `Snow Flurry', were under investigation. Clear and reproducible amplification products were produced with 3.0 μM MgCl2 and 30 ng template DNA/25 μL reaction mixer at annealing temperature 37 °C and 40 °C, compared with MgCl2 at 1.5, 2.0, and 2.5 μM. When annealing temperature increased, the RAPD-PCR stringency was increased, as expected. Stoffel fragment was found to provide highly reproducible results.
Increasing Teaching Effectiveness through Collaborative Learning Activities
Authors: Sanchez Elsa , Craig Richard
Published: February 2019

The Plant Systematics course at Penn State University was reformatted in 1995 based on a three-dimensional model. It now includes several collaborative learning activities: a learning fair hosted by the enrolled students for elementary school students; applied laboratory exercises; and applied laboratory examinations. Each activity has a specific objective and was constructed to strengthen teaching effectiveness and to aid students in developing useful skills for future employment. A survey was administered to students enrolled in the course from 2003 through 2005 in part to assess the collaborative learning activities. Most students “strongly agreed” or “agreed” that they liked working in collaborative groups and learned from other group members. Students preferred working in groups for laboratory examinations more than for the Asteraceae Fair and learned more from their peers while completing the laboratory exercises than in laboratory examinations. Student participation in the lecture portion of the course increased as collaborative learning activities were completed. Camaraderie with peers through group work may have created an atmosphere conducive to participation and/or involvement during lectures. Organization and planning were vital to the success of these activities, as were using small groups and providing adequate incentives for completing activities. These activities engaged students to become active participants in the teaching and learning process.
Assessing a Garden-based Curriculum for First Graders in Iowa: Parental Perceptions of Change
Authors: Haynes Cynthia , Hilgers Kimberly , Olson Joanne
Published: February 2019

The interest, use, and recognized benefits of gardens as educational tools for youth has increased in recent decades and has prompted the development of garden-based curricula for use in schools. Iowa State University Extension developed Growing in the Garden (GITG), a curriculum designed for use in kindergarten through third grade classrooms. This study examined the impact of the GITG curriculum on the awareness and interest of first graders in the areas of science, nutrition, and the environment. A survey was used to determine parental perceptions of their child's interest and awareness after experiencing three lessons from the GITG curriculum. Forty-seven parents (60.2% response rate) of first graders from four classrooms in Iowa completed the survey. A significant number of parents surveyed noted an increased awareness and interest of their children in the areas of science and the environment. Factors such as socio-economic status, ethnicity, and gender did not influence the outcomes.
Hurricanes Rita and Katrina: Impact on Louisiana's Green Industry Professionals
Authors: Owings Allen , Fortson Ginger , Bush Edward , Kuehny Jeff
Published: February 2019

Hurricane Katrina (Aug. 2005) and Hurricane Rita (Sept. 2005) were devastating to the central U.S. Gulf Coast region. Hurricane Katrina caused an estimated $10–11 million in wholesale nursery crop damage in Louisiana, while Hurricane Rita caused an estimated $5 million in damages. Average wholesale nursery crop sales in Louisiana account for about $120 million annually. 317 wholesale growers in Louisiana (49% of the state total) suffered damages due to Hurricane Katrina, while 158 wholesale growers (24% of the state total) suffered damages due to Hurricane Rita. Louisiana's retail plant dealers affected by Hurricane Katrina numbered 367 (28% of the state total). Louisiana's retail plant dealers affected by Hurricane Rita numbered 329 (24% of the state total). Retail plant dealers accounted for $511 million in sales in 2002, the year for which figures are most recently available. In the landscape and horticultural services segment of Louisiana's green industry, 703 (36%) were impacted by Hurricane Katrina and 450 (23%) were impacted by Hurricane Rita. While growers and retailers experienced economic hardships ranging from 1 month to permanent, most landscape contractors and horticultural service providers rebounded quickly and were actively involved in storm cleanup and recovery. Some, however, lost equipment, office structures, storage buildings, and vehicles. It is estimated that at least 20,000 of the 56,600 green industry employees in Louisiana were affected by Hurricanes Katrina and/or Rita to some degree. Louisiana's green industry overall provides about $2.2 billion in economic contributions annually.
Manipulating Light Intensity and Fall Fertilization to Influence Photosynthesis and Freeze Resistance of Azaleas
Authors: Henning Frank , Smalley Timothy J. , Lindstrom Orville M. , Ruter John M.
Published: February 2019

On 1 May 2004, a 4 × 2 split-plot experiment was initiated in Athens, Ga., on Rhododendron ×kurume `Pink Pearl'. The four main-plot treatments were low irradiance, low irradiance May–October, low irradiance November–May, and high irradiance (high and low correspond to average daily PPF of 23.6 and 10.4 mol·m-2·d-1). The two subplot fall fertigation treatments were 75 mg·L-1 of nitrogen (N) and 125 mg·L-1 N. Plant stem tissue was harvested monthly from November to March, and analyzed for freeze resistance (LT50). Maximum quantum efficiency of PSII (Fv/Fm) was analyzed monthly with a Mini-pam photosynthesis yield analyzer. No interactions existed between fertilizer application and light intensity and the 125 mg·L-1 N fertilizer treatment reduced freeze resistance of azalea stems throughout the study. Fall fertilization had no effect on fluorescence and no interactions existed between fertilizer and irradiance treatments. In November, plants that received low irradiance May–October were less freeze-resistant than plants from the high-irradiance treatment. However, in January, plants that received low irradiance throughout the study were more freeze-resistant than plants that received the high-irradiance treatment. In November, Fv/Fm was higher in the low irradiance and low irradiance November–May treatments. In February and March, Fv/Fm was lower in the low May–November treatment that received low irradiance during summer than the low November–May treatment that received low winter irradiance. The use of shade to reduce irradiance may delay the acquisition of freeze resistance in fall. However, shade may reduce photosystem damage and increase a plants ability to acquire and maintain greater freeze resistance.
1-Methylcyclopropene, CO2, and Diphenylamine Interactions with External CO2 Injury of `Empire' Apples
Authors: Razafimbelo Fanjaniaina , Nock Jacqueline F. , Watkins Chris B.
Published: February 2019

The `Empire' apple cultivar is susceptible to external CO2 injury, a physiological disorder that is expressed as tan-colored, smooth, watersoaked areas that become irregularly shaped, rough, depressed, and wrinkled. 1-Methylcyclopropene (1-MCP) may increase susceptibility of fruit to external CO2 injury during controlled atmosphere (CA) storage. We have investigated the effects of 1-MCP on external CO2 injury of `Empire' apple using several approaches. 1) Fruit were treated with 1%, 2.5%, and 5% CO2 during storage. Higher injury levels were associated with exposure to higher CO2 concentrations. 2) Fruit were exposed to 2.5% or 5% CO2 for 3-week periods throughout storage, otherwise being kept at 1% CO2. Most injury occurred in fruit treated with elevated CO2 during the first 3 weeks of storage, and 1-MCP did not extend the period of susceptibility to injury. 3) Exposure of fruit to CA with 5% CO2 after harvest was delayed for up to 14 days. Susceptibility to injury remained high during the delay in 1-MCP-treated fruit in contrast to untreated fruit. 4) Fruit were treated with 250, 500, and 1000 μL·L-1 diphenylamine (DPA), an antioxidant applied for control of superficial scald that is known to prevent susceptibility of fruit to CO2 injury at 1000 μL·L-1. The DPA eliminated injury in 1-MCP treated fruit, even at 250 μL·L-1. Our data show that 1-MCP increases susceptibility of `Empire' apples to external CO2 injury and extra care is therefore required to avoid fruit losses. Nonchemical means may reduce losses, but only DPA application has been shown to eliminate risk of injury.
Effect of Potassium Concentration on a Hybrid Phalaenopsis Grown in a Bark Mix or Sphagnum Moss
Authors: Wang Yin-Tung , Tsai Amy Ching-Jung
Published: February 2019

Vegetatively propagated plants (15-cm in leaf spread) of a white-flowered Phalaenopsis Taisuco Kaaladian clone were imported bare-root in late May and planted in a mix consisting of three parts of medium-grade fir bark and one part each of perlite and coarse Canadian peat (by volume) or in Chilean sphagnum moss. All plants were given 200 mg·L-1 each of N and P, 100 mg·L-1 Ca, and 50 mg·L-1 Mg. K concentrations were 0, 50, 100, 200, 300, 400, and 500 mg·L-1. After 7 months, plants grown in moss produced an average of two more leaves than those in the bark mix (4 to 5 vs. 2 to 3 leaves), regardless of K rates. In any given medium, K rate did not alter the rate of leaf production. The K rate did not affect the size of the top leaves when grown in the bark mix. However, plants grown in moss had increasingly longer and wider top leaves as K rate increased. The lower leaves on plants in the bark mix receiving no K showed deficiency symptoms of purple tinting, yellowing, necrosis, and even death. Yellowing and necrosis started from the leaf tip and progressed basipetally. The K at 50 mg·L-1 reduced and 100 mg·L-1 completely alleviated the symptoms of K deficiency. Plants grown in moss and receiving no K showed limited signs of K deficiency. Flowering stems started to emerge (spiking) from plants in the bark mix up to 4 weeks earlier than those planted in sphagnum moss. For plants receiving no K, all plants in the bark mix bloomed, whereas none planted in sphagnum moss produced flowering stems. Overall, at least 200 mg·L-1 K (∼250 mg·L-1 K2O) is recommended to produce quality plants with maximum leaf growth and early spiking.
Interaction Between Water and Nitrogen Application on Yields and Water-use Efficiency of Tomato and Pepper in Sandy Soil
Authors: Zotarelli Lincoln , Scholberg Johannes , Dukes Michael , Snyder Hannah , Munoz-Carpena Rafael , Simonne Eric
Published: February 2019

Several practices have been adopted to minimize water use and potential N leaching of vegetable production systems, including use of drip irrigation, plastic mulch, and fertigation. However, these practices may not be adequate on sandy soils with poor water and nutrient retention capacities. The objectives of this study were to evaluate the interactive effects of irrigation practices and fertilizer rates on yield, fertilizer requirements, and N-leaching of pepper and tomato production systems. Bell pepper and tomato were planted on plastic mulched to evaluate the effects of three nitrogen (N) fertilizer rates (154, 192, 288 kg·ha -1 N for pepper vs. 166, 208, and 312 kg·ha-1 N for tomato) and three irrigation scheduling methods were evaluated. Depending on sensor readings, soil moisture sensor (SMS) irrigation treatments allowed up to five watering events per day where as for the fixed duration treatment irrigation was applied once a day. For tomato, the effect of subsurface drip irrigation (SDI) was also evaluated. Compared to TIME, use of SMS control system reduced water use by 29& to 44% and 37% to 66% for tomato and pepper, respectively. Tomato yield was significantly higher on SMS and SDI treatments compared to TIME treatments. For pepper yield and biomass accumulation were not affected by irrigation treatments. The average yields were 24.6 and 27.8 Mg·ha-1 of fresh marketable fruits for pepper and tomato, respectively. Nitrogen rate did not affect yield and optimal yield N rate did not affect yield for either crop. On average, SMS treatments increased irrigation water use efficiency 2–3 times compared to TIME treatments for both tomato and pepper.
Irrigation and Rootstocks Affect Water Use, Growth, Nutrition, Yield, and Fruit Quality of `Fuji' and `Gala' Apples
Authors: Fallahi Esmaeil , McFerson James R. , Fallahi Bahar
Published: February 2019

Many fruit growers in the Pacific Northwest region prefer to use a sprinkler system to produce high-quality fruit and to establish a cover crop in the orchard. However, water shortage mandates the use of more efficient methods of irrigation, such as drip. In this long-term experiment, the effects of seven irrigation systems for `Fuji' and two irrigation systems for `Gala' on five rootstocks on tree growth, water use, fruit quality, and mineral nutrients were studied. All forms of drip systems used less water than full micro-sprinkler (SP). Partial root drying sprinkler (PS) used 50% less water than SP. Trees with partial root drying drip and deficit drip had to receive 65% of full drip to survive. Each `Fuji' tree with SP used about 5397 L of water in 2004 and 5833 L in 2005, while each tree with full drip used 2403 L in 2004 and 3438 L in 2005. Thus, trees with full drip used 41% to 55% less water than those with SP system without any reduction in fruit quality. This leads to a major savings in the cost of fruit production. Fruit weight in trees with full drip was always greater than those with PS or deficit drip. Fruits with SP system had lower soluble solids than those with PS. Fruits from trees with partial drip had a higher starch degradation than those with other systems. Leaf minerals, particularly N and K, were affected by irrigation systems. `Pacific Gala' trees on B.9 rootstock were more precocious than those on Supporter-4 rootstock. In general, `Pacific Gala' on RN-29 had better tree performance and fruit quality than those on other rootstocks. The calculation of water requirements on a tree-use basis provided an excellent guide for drip irrigation.
Growth and Yield Improvement of Newly Planted `Honeycrisp' Apple Trees with Preplant Soil Amendments and Rootstocks
Authors: Moran Renae
Published: February 2019

Preplant soil-incorporated compost, mycorrhyzal innoculation (MI) at planting, and the combination of the two were tested for growth and yield increase of `Honeycrisp' apple trees on two rootstocks, M.26 and G.16. Compost was added at a rate of 0.51 m3 per tree. Within each main plot of compost or no compost were planted four trees with two on each rootstock. Noncompost plots were fertilized with N in year 1 and N, K, and Mg in year 4. The MI had no effect on growth until the third and fourth years after planting when annual trunk growth and tree height were greater than the untreated control. Compost increased trunk growth in the third and fourth years, but decreased growth in the fourth year when combined with MI. G.16 had greater trunk growth and tree height than M.26 in years 3 and 4. Fruiting was delayed by pruning at planting, so trees fruited for the first time in the fourth year. Bloom and yield were not increased by MI. There was more bloom and yield on G.16 than on M.26. Yield of G.16 was increased by compost from 0.08 to 1.2 kg/tree. The combination of MI and compost increased bloom compared to the control, but not yield, which was 0.3 kg/tree. Compost increased bloom but not yield of M.26, since this rootstock had low yield when planted in compost, 0.2 kg/tree, and none when planted without compost.
The Effects of Several Key Factors on the Efficacy of Paclobutrazol Liner Dips for the Control of Stem Elongation in Bedding Plants
Authors: Schnelle Rebecca A. , Barrett James E.
Published: February 2019

The paclobutrazol liner dip is a plant growth regulator application technique that is becoming widespread in the commercial bedding plant industry. This technique, in which plug trays are dipped in a solution of paclobutrazol before transplant, is an efficient method for applying this growth regulator to a large number of plants. In previous studies, significant variability in size control was documented following liner dip treatments with identical solution concentrations. To elucidate the causes of this variability, three bedding plant species with varying levels of paclobutrazol sensitivity (Petunia ×hybrida, Impatiens wallerana, and Scaevola aemula) were treated with paclobutrazol liner dips under various conditions. Four factors identified in previous studies that may impact the efficacy of paclobutrazol liner dips were evaluated in this study. The age of the cuttings at the time of treatment ranged from 2 to 4 weeks after propagation. The light intensity incident to the plants from 2 h before through 2 h following the time of treatment ranged from about 1000 μmol·m-2·s-1 in a greenhouse to 5 μmol·m-2·s-1 indoors. The relative moisture content of the plug media before the treatment was saturated or at 25%, 50%, or 80% dry down by weight, based on air-dried media. The amount of time the plug media remained in the paclobutrazol solution was 10 s, 30 s, or 2 min. Data were collected on stem elongation 3 weeks after transplanting and again 2 weeks later. The results confirm that all four factors tested interact with the concentration of paclobutrazol in the dip solution to determine the control in stem elongation achieved by the treatment.
The Influence of Plant Growth Regulators on Budbreak and Shoot Growth from Large Stem Segments of Acer saccharinum L.
Authors: Mansouri Katayoun , Preece John E.
Published: February 2019

A factorial combination of gibberellic acid (GA3) and benzyladenine (BA) was applied in 20% white exterior latex paint to large (40 cm long, >2.5 cm diameter) stem segments of Acer saccharinum L. (silver maple) to determine the effects on forcing new softwood shoots in the greenhouse or laboratory and the subsequent growth of these new shoots in vitro. Stem segments were harvested from 10-year-old field-grown coppice shoots. The GA3/BA-paint mixes were applied to the entire stem segments that were forced in plastic flats filled with 1 perlite: 1 vermiculite (by volume) and watered with care so as not to wet the new softwood shoots. The flats and stem segments were drenched weekly with Zerotol (0.18% H2O2). The softwood shoots were harvested when they were at least 3 cm long. After disinfesting and rinsing, the nodal and shoot tip explants were established aseptically in vitro on DKW medium with no cytokinin or with 10-8M thidiazuron. Coppice shoots were harvested, cut, and painted on 9 Sept., 28 Oct., and 12 Dec. 2005. Although there were no significant differences in shoot production among stem segments painted with various combinations of GA3/BA, stems treated with plant growth regulators produced a mean of 2.7, 1.8, or 0.5 shoots for the three harvest dates compared to 0.5, 0.0, or 0.25 shoots on control stem segments. It is well-known that shoot forcing is poor from September through January; however, use of GA3/BA resulted in growth of dormant epicormic shoots. Shoot tip explants produced the most shoots in vitro after 8 weeks if they were harvested from stem segments treated with 0.03 mM GA3, whereas nodal explants produced the most shoots if harvested from segments that had been treated with 0.01 mM GA3.
Response of Seed Potato (Solanum tuberosum) Cultivars to Glyphosate
Authors: Hatterman-Valenti Harlene M. , Auwarter Collin P. , Mayland Paul G.
Published: February 2019

Field trials were initiated during 2004 at a dryland site near Prosper, N.D., to evaluate the effects of simulated drift from glyphosate to `Russet Burbank' and `Red Lasoda' seed potato during the early senescence stage. Glyphosate was applied at rates 1/3, 1/6, 1/12, 1/24, and 1/48 the use rate for spring wheat desiccation on 10 Sept. 2004 with a CO2 pressurized sprayer operated at 280 L/ha and 276 kPa. The amount of a.m.S added to the spray solution was also reduced accordingly. Following harvest, samples from each plot were placed into cold storage until the following March. A subsample from each plot was slowly warmed to initiate sprout formation. Remaining samples were cut into 57-g pieces, dusted with a seed piece treatment, and stored at 18 °C with about 90% RH until planted. Plots consisted of two 3-m rows at 91 cm-row spacing with a border row on each side and three spacer plants between plots. The trial was arranged as a randomized complete block with four replications. Plots were desiccated on 12 and 19 Sept. and harvested 11 Oct. Tubers were hand-graded shortly after harvest. Results indicated that glyphosate at 70 g ae/ha or more inhibited tuber budbreak by 75% or more compared to untreated. In the field, injury was observed as delayed emergence and, in several instances, no plants emerged. Total yield for `Red Lasoda' was 34.8 Mg/ha for the untreated, which was significantly greater than glyphosate treatments of 280, 140, and 70 g ae/ha. `Russet Burbank' total yield was considerably less at 23.5 Mg/ha for the untreated. Both the untreated and glyphosate at 18 g ae/ha had significantly greater total yields compared with glyphosate treatments of 280, 140, and 70 g ae/ha.
Integrating Root Interception Capacity and Crop Nitrogen Demand into BMPs for Vegetable Crops
Authors: Scholberg Johannes , Morgan Kelly , Zotarelli Lincoln , Simonne Eric , Dukes Michael
Published: February 2019

Most strategies used to determine crop N fertilizer recommendations do not address potential environmental issues associated with agricul-tural production. Thus, a more holistic approach is required to reduce N loading associated with vegetable crops production on soils that are prone to N leaching. By linking fertilizer N uptake efficiency (FUE) with irrigation management, root interception capacity, and N uptake dynamics, we aim to improve FUE. Nitrogen uptake for peppers, tomato, potato, and sweet corn followed a logistic N accumulation patterns. Up to 80-85% of N uptake occurred between 4 to 7 weeks (sweet corn) vs. 6 to 12 weeks (other crops), while N uptake during initial growth and crop maturation was relatively low. Maximum daily N accumulation rates occurred at 5 weeks (sweet corn) vs. 8-10 weeks (other crops) and maximum daily N uptake rates were 4-8 kg N/ha. Overall FUE for most vegetables may range between 23% and 71%, depending on production practices, soil type, and environmental conditions. Maximum root interception capacity was typically attained 3 to 5 weeks prior to crop maturity. It is concluded that, during initial growth, root interception may the most limiting factor for efficient N use. Although recent uptake studies have shown that FUE may be highest toward the end of the growing season, this may not coincide with the greatest crop demand for N, which occurs during the onset of the linear growth phase. As a result, yield responses to N applied later in the season may be limited. Integration of these results into best management practices and expert systems for vegetable production can minimize the externalities associated with commercial vegetable production on vulnerable soils in the southeastern United States.
Some Biochemical Changes in Carrot Roots Induced by Erwinia carotovora var. carotovora
Authors: Kumaresan Parthiban Valnaickenpalayam , Velappan Prakasam , Kuppusami Prabakar , Muthu Thangaraju
Published: February 2019

Carrot is a rich source of nutrients. Carrots contains carotene and lycopene, which gives bright color to the roots. The quality of the carrots was assessed based on the carotene, lycopene, and other biochemical constituents such as sugars, starch, and protein. To study the effect of various isolates of the Erwinia carotovora var. carotovora on the above biochemical constituents, the pathogens were inoculated and the contents were analyzed separately at 1, 2, 3, 4, and 5 days after inoculation. The contents of ß-carotene increased significantly due to all the three isolates of the pathogen and the Coimbatore isolate recorded highest of 36.03%. The same trend was also observed in the lycopene content, with 93.55% increase over control. The contents of total and reducing sugars were found to significantly increase due to inoculation with the pathogen. The starch content showed a decreasing trend in all the isolates tested. The maximum reduction of 62.98% was observed in the roots inoculated with Coimbatore isolate. The protein content showed a decreasing trend up to 5th day of inoculation, and further reduction of about 25.45% was recorded with Coimbatore isolate on the 5th day. The total phenol content in the roots of carrot decreased significantly, and reached the least on 5th day due to the infection by all the three isolates and the maximum reduction of 22.79% was observed in roots treated with Coimbatore isolate.
Encapsulation of Naturally Occurring Antifungal Compound into ß-cyclodextrins: A New Technology for Reducing Postharvest Losses
Authors: Almenar Eva , Auras Rafael , Rubino Maria , Harte Bruce
Published: February 2019

The United States is the world's largest producer of blueberries and strawberries. Successful marketing for both of them requires fruit of the highest quality and appearance. However, these fruits have a relatively short postharvest life, mostly due to the incidence of molds such as Colletrotrichum acutatum, Alternaria alternata, and Botrytis cinerea. At present, several natural occurring plant volatiles have been shown to be effective against fungal growth, but, even so, those compounds could not be maintained at constant concentration during the whole postharvest period due to their volatility. In this work, two naturally occurring aldehydes (acetaldehyde and hexanal) were tested and compared against the growth of the above mentioned fungi at 23 °C. After that, the most effective antifungal compound for each fungus was encapsulated in ß-cyclodextrins (ß-CD) and tested during storage period. Both aldehydes were effective in reducing and avoiding fungal proliferation depending on concentration. Fungal proliferation depended on daily, and not initial, volatile concentrations. Volatiles encapsulated in ß-CD showed higher antifungal activity compared to that obtained using the pure volatile during storage. Tested volatiles showed both fungicidal and fungistatic capacities after storage of fungal cultures in air. Results suggested ß-CD-acetaldehyde and ß-CD-hexanal complexes can be used as a new technology to release a naturally occurring antifungal compound during storage against several fungal diseases.
The Inheritance of Bacterial Soft Rot Tolerance through Stem Scar Water Infiltration in Tomato
Authors: Smith Sarah M. , Scott John W. , Bartz Jerry A.
Published: February 2019

When tomato (Lycopersicon esculentum Mill.) fruit come in contact with water at the packing house dump tanks, they can infiltrate water through the stem scar. If the water is infested with Erwinia carotovora, the fruit can infiltrate the bacteria, which will later develop into bacterial soft rot. To determine the inheritance of low water infiltration and thus tolerance to soft rot, a complete diallel was produced using six parents that infiltrate different amounts of water. The parents and hybrids were grown in a completely randomized block design with three blocks and 10 plants per block. The amount of water infiltrated by the fruit was measured by the change in weight after the fruit were immersed in water in a pressure cooker for 2 min. Both general combining ability (GCA) and specific combining ability (SCA) were significant, with GCA having a higher significance than SCA. There appeared to be a cytoplasmic effect on water uptake, where less water was taken up when the low-uptake parent was used as a female. When orthogonal contrasts were performed on reciprocal hybrids from parents that were significantly different, 33% of them were significantly different.
Variation for Tipburn Resistance in Lettuce
Authors: Hayes Ryan
Published: February 2019

Tipburn (TB) is a physiological disorder that results in necrosis along the margins of lettuce leaves. The disorder is objectionable to consumers and reduces the shelf life of whole and minimally processed lettuce. The objectives were to 1) determine the variation for tipburn resistance in iceberg, romaine, green leaf, and red leaf cultivars; and 2) determine the genotype × location interaction for tipburn resistance. Tipburn incidence was recorded on 10 plants in each of three repetitions in Salinas, Calif., and Yuma, Ariz., trials with 20 iceberg, 21 romaine, 11 green leaf, and six red leaf cultivars. Data were analyzed using analysis of variance type statistics of ranked data. Variation for TB resistance was found in all lettuce types at both locations, although iceberg cultivars (average percentage of TB = 31% Salinas; 77% Yuma) had significantly (P < 0.01) higher levels of resistance at both location than romaine (58% Salinas, 81% Yuma), green leaf (52% Salinas; 88% Yuma), and red leaf (43% Salinas, 89% Yuma). The Yuma, Ariz., trial was more conducive for TB, and had less variation (range of percentage of TB = 33% to 100% Yuma, 0% to 100% Salinas). Four iceberg, one green leaf, and one red leaf genotype with industry acceptable levels of TB (<5%) were identified in the Salinas environment. Genotype × location interaction was present (P < 0.01), and included rank order changes within all lettuce types. The correlation between the locations was low, 0.26, but significant (P = 0.045). A need exists for romaine, green leaf, and red leaf germplasm with improved TB resistance, particularly in the Yuma environment. The presence of variation within each lettuce type and genotype × location indicates that genetic improvement should be possible using within type crosses followed by selection in the Yuma or Salinas target environment.
Response of Lowbush Blueberry to Several Organic Fertilizers
Authors: Smagula John M. , Fastook Ilse W.
Published: February 2019

Four organic fertilizers were evaluated in a commercial lowbush blueberry field with a history of N and P deficiency. In nonorganic production, diammonium phosphate (DAP) is the standard fertilizer for correcting N and P deficiency. Nitrogen a rate of 67 kg·ha-1 [Renaissance (8-2-6), ProHolly (4-6-4), Pro Grow (5-3-4), Nutri-Wave (4-1-2), or DAP (18-46-0)] was applied preemergent to 1.8-m × 15-m treatment plots. Leaf N and P were deficient (<1.6% and 0.125%, for N and P, respectively) in the unfertilized plots that served as controls. DAP and Pro-Holly raised leaf N to satisfactory levels (>1.6%). Only DAP raised leaf P concentrations (0.144%), compared to controls (0.122%). Leaf K was not deficient, but was raised by Pro-Holly. Soil pH was slightly lowered by Renaissance (4.2) and raised by Pro-Holly (4.4), compared to the control (4.3). Soil P concentrations were raised by DAP and soil S by Pro-Holly. Soil K was raised by all fertilizers except DAP, compared to the control. Pro-Holly and DAP were equally effective in increasing stem height, branching, branch length, flower bud formation, and yield, compared to the control and the other organic fertilizers. Pro-Holly could effectively substitute for DAP in organic wild blueberry production.
Genotypic Variability of Iron and Zinc in Sweetpotato
Authors: Courtney Michael W. , La Bonte Don
Published: February 2019

Sweetpotato [Ipomœa batatas (L.) Lam.] is a major subsistence crop in southern Africa, where iron and zinc deficiency in humans is an important health problem. A cultivar of sweetpotato that is suited for subsistence farming in this region and that is high in iron and zinc could be an important means of combatting these deficiencies. As part of a program of the HarvestPlus program, under the auspices of the International Potato Center (CIP) to develop such a cultivar, we are working to identify the high and low range of iron and zinc in sweetpotato cultivars grown throughout the world by testing a number of cultivars for these nutrients. Subsidiary objects include determining the heritability of iron and zinc levels and surveying the variability in the levels of these nutrients from root to root on the same plant, from plant to plant of the same cultivar, from the proximal to the distal end of a given root, and from cambium to cortex. For the roughly 80 cultivars in the genotypic variability study, results showed a three-fold difference between the high- and low-yielding cultivars on a fresh weight basis and a two-fold difference on a dry weight basis, for both iron and zinc.
Wool and Hair Waste as Nutrient Source for High-value Crops
Authors: Zheljazkov (Jeliazkov) Valtcho , Jeliazkova Ekaterina , Nedkov Nedko
Published: February 2019

Container and field experiments were conducted to evaluate sheep wool wastes and human hair wastes as soil amendments and nutrient sources for high-value crops. Overall, wool-waste or hair-waste additions to soil increased yields from basil, garden sage, peppermint, valerian, thorn apple, marigold, foxglove, and swiss chard; increased the amount of secondary metabolites (such as essential oils and alkaloids); increased NH4-N and NO3-N in the soil; and increased total N (and protein) content in plant tissue. The wool-waste or hair-waste additions did not affect soil microbial biomass, but decreased mycorrhizae colonization of plant roots. Scanning electron microscopy (SEM) and Energy Dispersive X-ray (EDX) analyses indicated that some of the wool and hair in soil from the container and field experiments (after two field seasons and several harvests) retained its original structure, a significant amount of S, some N, and was not fully decomposed. Results from this study suggest that wool and hair wastes can be used as soil amendment and nutrient source for high-value container or field crops.
Chemical Blossom Thinining on Prunus in New York
Authors: Osborne Jason L. , Robinson Terence L.
Published: February 2019

In 2004, we conducted a chemical thinning field study in Appleton, N.Y., on 5-year-old `Rising Star' peach trees on Lovell rootstock. Treatments included soybean oil or petroleum oil applied at 8% about 30 days before budbreak. Ammonium thio-sulfate (ATS) 3.5 gal/acre, ATS 5.0 gal/acre, lime sulfur (1%, 3%) plus Crockers fish oil 2 gal/acre, and Wilthin 6 pt/acre were applied at FB; and the grower standard hand-thinning treatment at 45 DAFB. Trees treated with thinning agents were not given supplemental hand thinning. The high rate of ATS, 5.0 gal/acre and Wilthin 6 pt/acre had the greatest thinning effect and reduced fruit set by 55% and 61%, respectively, compared to the untreated control. The high rate of ATS also increased fruit size 25%, but reduced yield by 45%. Soybean and petroleum oil treatments did not significantly reduce fruit set. Lime sulfur plus fish oil treatments 1% and 3% also did not significantly reduce fruit set. Although a significant reduction in yield was observed in the high rate ATS and Wilthin treatments, a greater proportion of the crop was in the larger size categories. In 2005, treatments included soybean oil 8% plus Latron B 1956 applied 18 days and 25 days before FB, Lime sulfur (2%, 4%) plus Crockers fish oil (2%) applied at FB, Ammonium thio-sulfate (ATS) 3.5%, 5.0%, Wilthin 1.9, 2.8 L (Entek, Inc.), plus Regulaid 473 mL per 935 L/ha applied at FB, Entry 1.5, 3.0%, Tergitol TMN-6 0.75, 1.5%, hand-thin flowers to a crop load of seven fruits per cm2 at FB and hand-thin fruit to 7 fruits per cm2 applied 45 days after FB.
Selective Summer Pruning as a Tool to Develop Compact `Sweetheart' Sweet Cherry Trees on Mazzard Rootstock
Authors: Nunez-Elisea Roberto , Caldeira Lilia
Published: February 2019

We tested two severities and four timings of summer pruning in 2-year-old `Sweetheart' (P. avium L.) trees on seedling mazzard (P. avium L.) rootstock to evaluate growth and precocity responses. Trees were planted at 3.6 m × 5.6 m (497 trees/ha). Canopies consisted of three to four scaffolds and about 20 current-season shoots. All shoots on summer-pruned trees (n=6) were either headed or tipped on 24 June, 9 July, 26 July, or 9 Aug. 2004. Control trees were trained as steep leaders, with comparative current season shoots left intact. Trees had no bloom in 2004 and negligible bloom or fruiting in 2005. All 2005 shoots were headed in late July, except for controls, where only leaders were headed. By late Fall 2005, controls were 3.4 m tall with a canopy diameter of 3 m, while headed and tipped trees were about 65% and 75% the size of controls, respectively. Growth modules consisting of the original shoot and subsequent growth showed distinct responses to summer pruning treatments. Control shoots did not branch in 2004 and modules had an average of 17 spurs. Headed shoots branched in 2004 (except those headed 9 Aug.) and produced compact modules with a similar amount (24 June) or about 25% fewer (later heading treatments) spurs than controls. Shoots tipped in 24 June or 9 July branched in 2004 and produced modules with about 50% more spurs than controls. Shoots tipped in 26 July or 9 Aug. produced no new growth in 2004 and modules had about 30% the spurs of controls. Selective summer pruning produced compact trees which are expected (based on spur number) to yield at least 15 kg of fruit in 2006 (4th year) and appear suitable for densities of about 750 trees/ha. Yields, fruit quality, and future canopy management will be discussed.
The Changing Needs with Time for Mineral Nutrition of an Organic Stone Fruit Orchard Under Mediterranean Conditions
Authors: Raviv Michael , Aviani Ido , Laor Yael
Published: February 2019

Fruit growers apply fertilizer at high rates with soil organic matter (SOM) below 2.0%. As organically certified fertilizers are costly, our objective was to compare the effects of two modes of organic nitrogen nutrition to conventional control on plum tree yield and soil properties. The orchard is located on a Vertisol soil, and planted to plums in 1998. The tested treatments were: A) conventional control, receiving an average of 350 kg of N/ha per year; B) fertilization using cattle manure compost (15 tons/ha per year) + feather meal (1 ton/ha per year); and C) a combination of the same amount of compost + 500 kg of feather meal/ha per year + leguminous cover crop (alfalfa, Medicago sativa cv. Gilboa). By 2003, the SOM of treatment A remained stable and that of treatments B and C increased by 36% and 91%, respectively. As a result, soil bulk density of treatments B and C declined with no change in A. During the first year, levels of soil nutrients were lower in treatments B and C than those in A, but they became higher after 2 to 3 years. Nitrification capacity of the soils of treatments B and C was higher than that of treatment A. This enabled a drastic reduction of the application rates of organic amendments without resulting a decline in the soil's nutrient content in the organic treatments over the next 3 years, due to continued mineralization of the SOM pool. Various soil microbial characteristics (microbial counts, total hydrolytic activity, functional richness, and diversity) were determined. In all these parameters the organic treatments showed higher levels than treatment A. Stem circumferences and yields were similar for all treatments. It can be concluded that soil productivity is affected by SOM, so that after achieving a threshold level of SOM, fertilization needs are reduced considerably.