bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the β-subunit Protein on Pericarp Softening, Cell Wall Hydrolysis, and Ultrastructural Changes in Ripening Tomato Fruit
Authors: Chun Jong-Pil , Huber Donald J.
Published: January 2019

The function of the β-subunit protein in the cell wall metabolism of ripening tomato fruit is unknown. We examined pericarp softening, and polygalacturonase isozyme 2-mediated cell wall and pericarp tissue hydrolysis using tomato fruit (`Ailsa Craig') expessing an antisense gene for the cell wall-subunit protein. Softening of pericarp tissue was accelerated in the β-subunit-deficient compared with wild-type fruits, decreasing from an average of 22 N at the mature-green stage (both lines) to 9 N (12.7, wild) at the turning-pink stage to 2.5 N (5.1, wild) at the ripe stage. Pectin solubilization was enhanced significantly in the antisense line compared with the wild type, but differences in depolymerization patterns were minimal. Scanning electron microscopy of pericarp tissue revealed no differences in the tomato lines at the mature-green stage. During ripening, the pericarp tissue of the antisense fruit exhibited a more extensive loss in cell wall rigidity evident from the collapsed appearance of cell walls. Application of purified PG2 to the cut surface of mature-green pericarp tissue induced ultrastructural changes paralleling those observed during ripening of the two fruit lines. Refracture of PG2-treated, mature-green pericarp tissue showed that enzyme activity was confined to the tissue surface in wild type fruit, but penetrated at least several cell layers in the antisense line. Although some workers have suggested that the role of the β-subunit is not related to PG1(PG2+subunit) formation, we conclude that the protein influences pericarp tissue softening and cell wall hydrolysis by limiting the mobility and catalytic capacity of PG2.
Protective Border Plantings for Ag/Urban Interfaces
Authors: Schrader Wayne L. , Robb Karen L. , Mellano Valerie J.
Published: January 2019

Protective border barriers were established at three sites in commercial floriculture, and strawberry fields in San Diego County, Calif. These border plantings were used to provide a physical barrier between agricultural fields and adjacent urban development, and to evaluate the effects of border plantings on insect populations, spray drift, and crop/barrier interactions. Border plantings consisted of native plants with overlapping flowering periods to provide nectar and pollen to beneficial insects throughout the year. Yellow sticky traps were used to monitor insect populations, and water sensitive paper was used to evaluate the reduction of spray drift by the border plantings. Results indicate that protective border plantings: 1) can be used to form attractive physical barriers that reduce visual pollution and spray drift; 2) provide habitat for pests as well as beneficial insects; 3) support beneficial insects that may help reduce the population peaks of pest insects during spring and summer months; and 4) have little effect on adjacent crop fields.
Foliar Application of Ethephon Decreases Apical Dominance in `Orchid' Petunia (Petunia × hybrida Vilm.-Andr.)
Authors: Haver Darren L. , Schuch Ursula K.
Published: January 2019

Ethephon was applied as a foliar spray to 36-day-old petunia seedlings to determine its effectiveness at reducing apical dominance by increasing lateral shoot development. Ethephon application at rates of 125, 250 and 500 mg·L–1 to whole shoots of Petunia × hybrida `Orchid' decreased apical dominance compared to the control. The average length of a lateral shoot increased 56% as ethephon application rates increased from 0 to 500 mg·L–1. In Expt. I, ethephon-treated plants had a greater number of laterals than control plants. The number of nodes produced before the first flower bud was initiated increased from 15 to 21 as rates of ethephon increased from 0 to 500 mg·L–1. Ethephon delayed anthesis up to 10 days when applied at 500 mg·L–1 and up to 8 days when applied at 250 mg·L–1. The number of visible flower buds increased in all ethephon-treated plants compared to the control. Ethephon at 250 mg·L–1, increased shoot and root dry mass 37.9% and 20.4%, respectively, compared to untreated controls. Roots appeared healthy in both experiments, but phytotoxicity (mild chlorosis) occurred in Expt. II on plants treated with 500 mg·L–1. The experiment was repeated twice with similar results.
The Introduction, Evaluation, Escape from Cultivation, and Ongoing Range Expansion of Ligustrum spp. On and Around the Texas A&M University Campus
Authors: McWilliams Edward , Rector Gretchen
Published: January 2019

For decades, the Texas A&M Univ. campus has been a center for USDA ornamental plant introductions. Historically, horticultural nurseries on the Texas A&M Univ. campus have served as foci from which exotic plants have dispersed and colonized surrounding areas. Pistachia chinensis, Ulmus parvifolia, Ligustrum quihoui, Ligustrum lucidum, and Sapium sebiferum have all established themselves on or near the campus and can be traced back to early introductions. Many Ligustrum taxa including selections of L. quihoui were screened at Texas A&M College in the 1930s. Clones of this species varied greatly in their ability to naturalize. The invasion lag phase and range of expansion varied with both clone and species. It is suggested that potential exotic ornamental plant introductions be carefully evaluated for their potential to become non-native invasive species as well as for their ornamental characteristics.
Effect of Ethephon on Tabasco Fruit Ripening
Authors: Mao Cailiang , Motsenbocker Carl E.
Published: January 2019

The effect of ethephon on fruit maturity in tabasco pepper (Capsicum frutescens L) was investigated in greenhouse studies. Two lines of tabasco pepper (`McIhenny Select' and `Hard Pick') that differ in ease of separation at the calyx-pedicel separation zone were used. Individual flowers were tagged at anthesis and intact fruit were treated with ethephon (500, 1000 μL) 29, 32, 35, and 38 days after anthesis. Untreated fruit were used as controls. The normal development from anthesis to mature red is 45 to 47 days for both lines. Ethephon treatment to tabasco fruit of both lines at 29 and 32 days after anthesis was effective in enhancing ripening by 3 to 7 days. `Mclhenny Select' ethephon treated fruit 35 days after anthesis were not affected. In contrast, `Hard Pick' fruit treated with ethephon at the high rate (1000 μL) 35 and 38 days after anthesis resulted in enhanced ripening compared to that of the control. These results indicate that the two tabasco lines differ in response to ethephon.
Soil Nitrogen Movement under Sustainable Vegetable Production Systems
Authors: Johnson Amy M. , Hoyt Greg D.
Published: January 2019

An experiment was established to determine the effect of different tillage practices, vegetable crop rotations, and pest management strategies on crop yield, plant diseases, pest and beneficial arthropods, weed species changes over time, and soil environmental consequences. This poster describes nitrogen movement from the various treatments over a 3-year rotation. The treatments are: 1) conventional tillage with chemically based IPM; 2) conventional tillage with biologically based IPM; 3) conservation tillage with chemically based IPM; 4) conservation tillage with biologically based IPM; and 5) conventional tillage with no fertilizer or pest management. Mid-season soil analyses with depth showed chemical-fertilized plowed and conservation-tilled treatments with more soil available nitrogen at most depths compared to the biological-based IPM systems (soybean meal was used as a nitrogen source). However, the biological-based systems did supply enough soil nitrogen to produce similar yield results as the chemical-based systems. Less soil nitrate was measured in the 30- to 90-cm depths at harvest from the biological-based systems than chemical-based systems. Conservation-tilled systems had greater nitrate with depth compared to conventional-tilled systems.
Conservation Tillage of Winter Broccoli in a Semi-arid Subtropical Environment
Authors: Makus D.J.
Published: January 2019

Winter broccoli (Brassica oleracea, L. Botrytis Group) production was evaluated under three tillage systems, conventional (CT), minimum tillage (MT), and no-till (NT), which were established in Aug. 1994. Cotton, followed by a legume, preceded broccoli in the yearly rotation. After three growing seasons, marketable broccoli yields were similar among tillage systems, but plant densities at harvest were lower in the NT system compared to the CT-grown broccoli plants. No-till-grown broccoli heads compensated for stand differences by producing slightly larger heads (P = 0.17). The percent marketable yield was not affected by tillage practice. Floret NO3, chlorophyll, and carotenoid concentrations were reduced when broccoli was grown by conservation tillage (MT and NT). At the end of the third growing season, the amount of germinable weed seeds in the upper 0-5 cm of soil was highest in the NT soil. Total plant weed populations were higher in conservation tilled soil. Total N, K, and Mg concentrations in the upper 30-cm soil profile were highest in the NT system. Total N, C, K, Mg, and P nutrient gradients were greatest in NT soil, whereas Na concentrations were greatest in CT soils. Min. tillage responses were generally intermediate to those of CT and NT.
Fruit Removal and Continual Defoliation Altered Papaya Fruit Production and Quality
Authors: Zhou Lili , Christopher David , Paull Robert E.
Published: January 2019

The source size and sink strength were modified by continual defoliation and fruit removal in `Sunset' papaya. Flower and fruit set, mature fruit mass, and TSS was recorded weekly. Fruit at four different stages of development were harvested at the end of the experiment. Fruit mass, respiration, sugar content, and sucrose phosphate synthase (SPS), sucrose synthase (SS), and invertase enzyme activities were compared. Continual defoliation resulted in lower new fruit set (25% of control), smaller fruit size (77% of control), and lower TSS (85% of control) in the 24-week experimental period. In contrast, there were 52% and 100% more new fruit when fruit were removed than in the control within the first 8 weeks and 24 weeks, respectively. Larger fruit size, earlier fruit development, lower respiration, and higher sugar contents were observed when fruit were removed at 140, 154, and 175 days from anthesis. No significant difference was found in TSS level in the mature fruit compared to the control. Fruit removal plus defoliation gave the same number and mass of new fruit as the control and slightly lower TSS in mature fruit than in the control. Fruit sugar was higher with increased fruit invertase activity and fruit age. Data confirmed that source–sink balance was critical for fruit set, development, and sugar accumulation in papaya.
Citrus Carbohydrate Levels were Related to Irrigation Frequency but Not Arbuscular Mycorrhizal Fungal (AMF) Inoculum
Authors: Fidelibus Matthew W. , Martin Chris A.
Published: January 2019

Sugar and starch concentrations in leaves and roots of Citrus volkameriana Tan and Pasq were measured in response to irrigation frequency and AMF inoculum. Non-mycorrhizal seedlings were treated with a soil inoculum from one of five different communities of AMF; two AMF communities from Arizona citrus orchard soils, and three communities from undisturbed desert soils. Plants were assigned to frequent (soil water tension > –0.01 MPa) or infrequent (soil water tension > –0.06 MPa) irrigation cycles and were container-grown in a glasshouse for 4 months before tissues were analyzed. Fungal inoculum source did not affect shoot or root carbohydrate levels. Plants grown under high irrigation frequency had increased leaf and root starch levels and increased root sugar levels compared with those under low irrigation frequencies. High irrigation frequency also increased shoot mass.
Development of Five Tropically Adapted Disease Resistant Dry Bean Varieties
Authors: Santana E.A. , Godoy-Lutz G. , Nin J.C. , Saladin F. , Beaver J.S. , Coyne D.P. , Steadman J.R.
Published: January 2019

Diseases are a primary constraint affecting yield and seed quality of dry beans (Phaseolus vulgaris) in the Dominican Republic. A collaborative dry bean breeding program to develop resistance to one or more diseases in different dry bean types was conducted in the Dominican Republic (DR) under a US-AID Title XII Bean/Cowpea CRSP involving breeders and pathologists in the Ministry of Agriculture, DR, Univ. of Nebraska, Lincoln, and the Univ. of Puerto Rico, Mayaguez. The origin and some characteristics of the five new dry bean varieties released in 1988 are described here. The black seeded `Arroyo Loro Negro' (MUS-N-4-H) (Type II a growth habit) was derived from the cross H-270 (MSU/UPR) X XAN-223 and has resistance to web blight and rust. The pedigree of the white seeded `Anacaona' (L-8020) (Type II a growth habit) is (2b-5-1/2 × NEP-2/Black Turtle Soup) X BON 355 (MSU). `Anacaona' is moderately resistant to web blight. The three red-mottled determinate Pompadour varieties were developed from the following crosses; `Saladin-97' (PC-21-SME) and `CIAS-95' (PC-21-SMA) from `PC-50'(DR) X BAT 1274 (CIAT) and `JB-178' (PR-JB-178) from `Jose Beta' (DR) X C1308 in Puerto Rico. These new high yielding Pompadour varieties have a higher level of field resistance to Andean pathotypes of rust in the DR than does `PC-50' the predominate variety.
Genome Mapping in Citrullus Populations Segregating for Fusarium Wilt Resistance
Authors: Hawkins Leigh K. , Dane Fenny , Rhodes Billy
Published: January 2019

Fusarium wilt, caused by the soilborne fungus Fusarium oxysporum f.sp.niveum(FON), is one of the most economically important diseases of watermelon (Citrullus lanatus) worldwide. FON has been divided into three races (races 0, 1, and 2) determined by differential pathogenicity assays. Most commercial cultivars are resistant to races 0 and 1; whereas none are resistant to race 2. Few morphological and isozyme variations are seen in the cultivated watermelon, but molecular markers, such as random amplified polymorphic DNA (RAPD), amplified fragment length polymorphisms (AFLPs) and simple sequence repeats (SSRs), have been shown to generate several polymorphisms. Segregating populations, derived from a cross between watermelon cultivar New Hampshire Midget, susceptible to all three races of FON and the resistant C. lanatus plant introduction PI 296341, were used to detect molecular markers linked to Fusarium wilt resistance. In a preliminary experiment, more than 180 10-mer primers were screened against the parents and the F1. Informative RAPD primers were identified and used in conjunction with AFLP and SSR markers to generate a genome map.
Influence of Selected Endomycorrhizae from the Sonoran Desert and Glomus intraradices on Growth Response and Gas Exchange of Hibiscus rosa-sinensis L. cv. Leprechaun
Authors: Egilla Jonathan N. , Davies Fred T.
Published: January 2019

Six endomycorrhiza isolates from the Sonoran Desert of Mexico [Desert-14(18)1, 15(9)1, 15(15)1, Palo Fierro, Sonoran, and G. geosporum] were evaluated with a pure isolate of Glomus intraradices for their effect on the growth and gas exchange of Hibiscus rosa-sinensis L. cv. Leprechaun under low phosphorus fertility (11 mg P/L). Rooted cuttings of Hibiscus plants were inoculated with the seven mycorrhiza isolates and grown for 122 days. Gas exchange measurements were made on days 26, 88, and 122 after inoculation, and plants were harvested on day 123 for growth analysis. Plants inoculated with the seven isolates had 70% to 80% root colonization at harvest. Plants inoculated with G. intraradices had significantly higher leaf, shoot and root dry matter (DM), leaf DM/area (P ≤ 0.05) than those inoculated with any of the six isolates, and greater leaf area (LA) than Desert-15(9)1 and 15(15)1. Uninoculated plants had significantly lower leaf, shoot, root DM, leaf DM/area and LA (P ≤ 0.05) than the inoculated plants. There were no differences among the seven isolates in any of the gas exchange parameters measured [photosynthesis (A) stomatal conductance (gs), the ratio of intercellular to external CO2 (ci/ca), A to transpiration (E) ratio (A/E)]. The relationship between inoculated and uninoculated plants in these gas exchange parameters were variable on day 122 after inoculation.
Rooting Softwood Cuttings from Forced Stem Segments of Adult White Ash
Authors: Van Sambeek J.W. , Navarrete Nadia E. , Preece John E.
Published: January 2019

On 10 Apr. 1997, the smaller branch on forked Fraxinus americana L. (white ash) trees in an 8-year-old clonal plantation were removed, cut into 25-cm-long stem sections, and placed horizontally in perlite under seven different forcing regimes. Sprouts from latent buds were excised 67 and 99 days later and trimmed to retain the apical pair of leaves and terminal bud. The basal 2 cm of each cuttings was set for 30 to 60 min in one of six aqueous dilutions made from a stock solution of 1% IBA and 0.5% NAA (Dip `n Grow) before placing in a 1 perlite: 1 vermiculite medium. Eight weeks after treating, cuttings data were collected. Most cuttings treated with 3200 mg/L IBA plus 1600 mg/L NAA quickly died. Survival (85%) and rooting percentage (86%) were similar for the remaining auxin-treated cuttings and controls with water only. Cuttings treated with 1600 mg/L IBA plus 800 mg/L NAA produced the most adventitious roots (6.2 roots), the longest adventitious root (22 cm), and longest combined sum of all adventitious roots (51 cm); however, these rooted cuttings died when transplanted to soil. Cuttings treated with 100 mg/L IBA plus 50 mg/L NAA or 400 mg/L IBA plus 200 mg/L NAA had more adventitious roots (3.2 roots) and total length of adventitious roots (370 mm/cutting) than cuttings treated with 40 mg/L IBA plus 20 mg/L NAA or controls with water only (2.2 roots, 220 mm long). Results indicate softwood cuttings forced on stem segments of adult white ash readily root under mist following a brief soak in a 400 mg/L IBA plus 200 mg/L NAA solution.
Lime and Lavender: The Ornamental Sweetpotato Wins Respect in the Landscape
Authors: McLaurin Wayne J. , Wade Gary L.
Published: January 2019

Impressive its first several seasons on the market, the ornamental sweetpotato (Ipomoea batatas) provides nearly carefree cascades of fade-proof yellow-green, purple, or variegated foliage that looks equally good on banks, in beds, or in hanging baskets. A foil for both bright and subdued flowering plants, such as abelmoschus or petunias, ornamental sweetpotatoes add both dramatic color contrasts and dimension to plantings of all kinds. As demonstrated at the 1996 Summer Olympics, large containers filled with ornamental sweetpotatoes, such as `Margarite' and `Blackie', and the muted greys, greens, purples, and golds of artemesia, fountain grass, and lantana create an unusual and dependable planting that holds up to heat and humidity and is generally pest-free. Cultivation requirements are minimal. Ipomea performs best in full sun with good drainage and regular garden soil. However, it will tolerate poor soil, dry conditions, even semi-shade as well. In spite of its horticultural and aesthetic qualitites, Ipomea has still to be utilized fully in home and commercial plantings. As new varieties are introduced and the spectrum of color increases, Ipomea should become a true mainstay of the ornamental industry.
Quantifying the Effect of Canopy Closure on Poinsettia Stem Elongation
Authors: Faust James E. , Klein Rob , Will Elizabeth
Published: January 2019

The rate of poinsettia stem elongation is affected by several factors, including light quality, i.e., specific wavelengths of irradiance. As the plants grow and the canopy closes, the red to far-red ratio is reduced and stem elongation is promoted. The objective of this project was to quantify the effect of canopy closure on the stem elongation rate of pinched `Freedom' poinsettias. In the first experiment, individual plants received 413, 645, 929, 1264, or 2580 cm2 of growing area at the time of pinch. The maximum rate of stem elongation for the five spacing treatments was 2.9, 3.8, 4.3, 5.6, or 7.5 mm/day, respectively. In the second experiment, plants were grown at a “tight” or a “wide” spacing as defined by the percentage of PPF transmission measured between plants. The “wide” spacing treatments allowed 50% PPF transmission, while the “tight” spacing treatment allowed 10% PPF transmission. A constant degree of closure was maintained by weekly adjusting plant spacing based on the PPF transmission measurements. The maximum rate of stem elongation of the “tight” spacing was 4.6 mm/day compared to 3.1 mm/day for the “wide” spacing treatment.
Breaking the Vegetative Cycle of Plant Materials Lectures
Authors: Arnold Michael A.
Published: January 2019

Routine lectures, even in topics as inherently appealing to students as plant materials classes, can become monotonous. Educational games can be effective mechanisms for breaking the classroom routine, stimulating student interaction, and reviewing key concepts in an alternative teaching/learning style. Three plant materials games that can be tailored to apply specifically to regional/local classes were developed based on popular television game shows. Basing the formats on games with which the students are familiar allows minimal time and effort to learn the rules and permits students to immediately participate in the activity. The names of the games are “Plant Pictionary”, “Plant Taboo”, and “Name That Plant”. A brief game of each can be completed within 15 to 20 min. The games were developed using plant morphology, taxonomy, aesthetic characteristics, and/or site requirement terminology introduced for general concepts or specific taxa covered in the course. Based on student evaluations, these activities were well received when periodically inserted into the lecture sessions. Participation and enthusiasm for the activities was greatest during the later half of the semester, likely due to the greater base of knowledge that could be incorporated into the games. The games worked best as group activities, particularly fostering good natured competition among laboratory sections. The general concepts of the games should be transferable to other subject matter areas.
IPM—A Problem-based Learning Approach
Authors: Rice Robert P.
Published: January 2019

The Cal Poly philosophy of “Learn and Understand by Doing” has been integrated with problem-based learning and the use of the latest technology to produce a class that closely simulates real-life pest control situations. Goals of the class, Disease and Pest Control Systems for Ornamental Plants, are to teach students pest monitoring, control and problem solving techniques, the use of resources including the internet and journals, and the use of the latest pest control equipment and application techniques. Students are shown pest situations and then work in groups to diagnose the problem, investigate management strategies, apply control measures, and monitor results. Weekly class presentations inform the class of the various projects and help to teach the class organization and presentation skills. Student evaluations and test performance have demonstrated that students achieve class objectives substantially better with the problem-based learning approach than with the previous lecture-based approach to the class.
Comparisons of Field-dependent and -independent Student Learning Preferences in an Ornamental Horticulture Class with an Emphasis on Computer-assisted Instruction
Authors: Kahtz Anthony W. , Kling Gary J.
Published: January 2019

Learning Preference differences and similarities of field-dependent/-independent students were investigated with an emphasis on the usage of a computer-assisted instruction (CAI) program designed for a woody plant identification class. Qualitative interviews further investigated each participant's cognitive learning style after administration of the Group Embedded Figures Test instrument. The findings were congruent with the theory of field dependency. In addition, results indicated that field independent students felt that using CAI was beneficial, but may prove to be more advantageous with provided structure. In contrast, field-dependent students did not feel there was any benefit in using a CAI program, but, with provided structure, benefits may occur. However, both field-dependent/-independent students would prefer a greater usage of visuals in this CAI program.
Fertilizer Placement Effects on Growing Medium Nutrient Distribution and Root Growth of Roses
Authors: Cabrera Raul I. , Perdomo Pedro
Published: January 2019

The effect of localized controlled-release fertilizer (CRF) topdressing applications on medium nutrient distribution and root growth was evaluated in containerized roses (20-L pots with peat-based medium). Small samplers were used to monitor the soil solution nutrient status in four vertically oriented quadrants of the medium profile. Average electrical conductivity (EC) and nitrogen concentrations ([N]) found in quadrants beneath the localized CRF supplies were significantly higher (from 1.6 up to 5.8 times) than in the rest of the quadrants. Nutrient distribution patterns in pots receiving evenly distributed CRF applications were affected by the placement of irrigation spray-stakes, with higher EC and [N] in quadrants receiving the least water. After a 12 week experimental period no significant differences in average new root mass and length densities were observed for pots receiving either localized or evenly distributed CRF applications. Reductions in root growth parameters were, however, observed in those quadrants farther away from the irrigation spray-stakes. Results from pots irrigated with a Hoagland nutrient solution applied with either a 360-degree spray-stakes or localized drippers showed a more prominent effect of water and nutrient localization on root growth.
Influence of Planting Stock Clove Size, Nitrogen Rate, and Planting Method on Elephant Garlic Production
Authors: Davis Jeanine M.
Published: January 2019

To produce large elephant garlic (Allium ampeloprasum L.) bulbs in the southeastern United States, stock cloves must be planted in the fall. During extremely cold winters, however, winter survival rates can be very low. A 2-year study was undertaken to examine practices to increase winter survival rates. Two clove sizes (≤20 g or >20 g), three nitrogen rates (112, 224, and 336 kg/ha), and three planting methods (flat, mulched, and hilled) were tested in a RCB design with four replications. For all planting methods, cloves were set in a shallow trench and covered with soil to ground level. This was also the flat treatment. For the mulched treatment, 7 cm of straw was spread on top. For the hilled treatment, soil was mounded 10 to 15 cm high over the ground level. Cloves were planted in early October and harvested in mid-June. Use of large planting stock cloves increased winter survival rates during the harsh winter, but had no effect during the mild winter. Both years, winter survival was reduced with the flat treatment. Yields of marketable bulbs were 4 to 5 times higher when >20 g cloves were planted than when ≤20 g cloves were used. Nitrogen rate and planting method had no effect on yields. The >20 g cloves also produced larger bulbs than the smaller cloves. Of the three planting methods, the flat treatment produced the smallest bulbs. Bulbs were much larger following the mild winter than the harsh winter.
under Organic Cultivation
Authors: Letchamo W. , Krutilina V.S. , Kireeva T.
Published: January 2019

St. John's Wort (Hypericum perforatum L.), a perennial from Hypericaceae, is one of the highly esteemed medicinal plants since ancient times. The tops are used for its soothing, calming antidepressant effects, wound healing, antispasmodic, and antiviral effects. Recently it has been found to be a natural substitute for “PROZAC™”. So far, most of the commercial supply of St. John's Wort originates from wild collections. Five different cultivars of Hypericum perforatum originating from Germany (`Due-1', `Due2') Canada (`Quebec'), United States (`TLF-1'), and Russia (`Russia') were grown under commercial organic cultivation. H. perforatum of Canadian origin (Quebec) and `TLF-1' from the United States (Washington and Oregon) were of a recent selection, while the German (Due-1, Due-2) and Russian cultivars were selected for higher yield and better concentration of the active constituents (essential oil, hypericin, and other related flavonoids). Seeds obtained from these cultivars were directly sown in the field, using animal manure, in Trout Lake Farm, Wash. There was a significant difference among the cultivars in morphology, flowering period, yield, and content of the essential oil. Cultivars Due-1, Due-2, and Russia showed an erect growth, with uniform flowering time and pattern, indicating the suitability of these cultivars for mechanical harvesting and better exposure of the flowers to sunlight. The highest herb yield was obtained from `TLF-1', while the lowest was obtained from `Quebec'. Cultivar TLF-1 came to flowering the latest, while `Due-1' was recorded to flower earliest and had the lowest shoot yield. The essential oil content of `Due-1', `Due-2' and `Russia' was significantly higher than `Quebec' and `TLF-1' cultivars.
Developmental Variations in the Content of Active Substances and Nutrients in Echinacea purpurea
Authors: Letchamo W. , Krutilina V.S.
Published: January 2019

Echinace from the Asteracea family has been among the top 10 marketed herbs in North America and Europe. So far, only a limited amount of Echinace originate from commercial cultivation. Echinacea purpurea has been commercially cultivated in the United States since the mid 1970s, in Russia since 1935, while in Europe since the 1960s. However, there has been no published information in the English language on methods of cultivation, expected yields, limiting factors, nutrient requirements, and the optimum plant development stage to obtain maximum yield and concentration of the biologically active substances for pharmaceutical and cosmetic processing. The objective of this investigation was, therefore, to study the general distribution of major nutrients and biologically active substances and the relationship between the two groups, and the pattern of the accumulation of cichoric acid, echnacoside, isobutylamides (tetraenes) and essential oil in commercially cultivated Echinacea purpurea. There was a significant variation in the content of essential oil, cichoric acid, and isobutylamides (tetraenes) in different organs and stages of the plant development. Similarly, the difference in the distribution of N, P, K, Ca, Mg, and Fe in different organs and developmental stages is demonstrated. The correlation between the content of the active substances and nutrients is demonstrated, while recommendations for an optimum harvesting stage and date are made.
Response of Plant Tissue Cultures to Various Light Spectra and Ultra-high Levels of Carbon Dioxide
Authors: Tisserat Brent
Published: January 2019

Growing plant tissue cultures under specific light quality treatments (e.g., white, red, blue, yellow, or orange light) has been conducted to study altered morphogenesis. Characteristic differences in leaf shape, rooting, axillary shooting and fresh weights may be obtained depending on the light quality treatments employed. However, light quality treatments also results in a reduction of available light intensity provided to the culture which can be detrimental. Long-term treatments (i.e., 8 weeks) with certain light treatments may result in severe stunting in growth or even culture death. This situation can be corrected by increasing the light intensity for each light quality treatment employed or reducing the time of treatment exposure. As an alternative, this study was conducted to determine if coupling colored light treatments with enhanced ultra-high CO2 levels (e.g., 10,000 Lμliter–1 CO2) could result in growth rates comparable to that occurring in white light treatments. The growth results of employing several species (i.e. lettuce, thyme, citrus) shoot cultures under various light quality treatments with and without ultra-high CO2 levels are presented. Ultra-high CO2 levels enhanced culture growth regardless of the light treatment employed. In some cases, cultures that were given ultra-high CO2 levels with several light treatments exhibited growth rates that exceeded that obtained from white light treatments. Based on these results, ultra-high CO2 levels may play a role in testing and obtaining a beneficial effect from light quality treatments on plant tissue cultures.
Variability of Clonal Selections of Poinsettia `Eckespoint Monet'
Authors: Wilfret Gary J.
Published: January 2019

The introduction of poinsettia (Euphorbia pulcherrima) cultivar Eckespoint Monet in 1994 provided a novelty bract color that promised to be a welcome addition to the array of poinsettia colors available. The light tan bracts of `Monet' are splashed with flecks of medium rose, with the flecks concentrated on the margins. In warm growing areas, the bracts' base color appears faded and the rose flecks are not intense, which delays time to market and reduces consumer acceptance. Plants with darker rose flecks were observed in 1994 and clonal selections were saved that had a range of very light to very dark rose flecks. Further selections within these clones were made in 1995 based on bract color and consistency. A cultivar trial in 1996 evaluated 26 of these clones compared to the true `Monet' and a `Dark Monet' from the Ecke Ranch. Single plants were grown in 20-cm containers and pruned twice. Data were recorded on plant height and diameter, days to first bract color, marketable, and anthesis, the percentage of mutant laterals, and bract color. Plant height and diameter and days to anthesis were not significantly different among the selections but the clones with darker bracts were marketable up to 5 days earlier than `Monet'. Selections with darkest rose flecks occasionally mutated to solid red but these laterals could be easily rogued in propagation beds by using the dark red petioles as a selection criterion. These selections can be too dark when grown in cool climatic areas but are more intense and acceptable in warm regions of the United States.
The Effect of Rhizosphere Competence on Colonization of Sweet Corn Roots by Biocontrol Fungi in Differing Soils
Authors: Björkman Thomas , Blanchard Lisa , Harman Gary E
Published: January 2019

To be effective, biocontrol agents, fungi need to colonize roots under a wide range of conditions. The ability do so is called rhizosphere competence. A common beneficial fungus, Trichoderma harzianum, has been bred to produce a new strain, T-22, that has exceptionally high rhizosphere competence. In field experiments, we have demonstrated that T-22 was resistant to edaphic conditions that reduce colonization by indigenous Trichoderma species, so that it can provide protection against root pathogens. Well-drained sand, stone or gravel soils supported lower populations of wild Trichoderma than did loams (100.5 vs 10 3.3 cfu/g), but populations of T-22 were high in all soils (>104 cfu/g). In a multivariate analysis of soil characteristics affecting colonization, only soils with low Ca and low pH had reduced populations. No other measured soil characteristics were correlated with colonization. When sown in the field at different initial soil temperatures ranging from 10 to 27 °C, T-22 populations were unaffected by temperature, having a population from 104.6 to 105.4 cfu/g. Indigenous strains were 103 in cold soils, peaked at 104 at 15 °C, declining in later sowings due to higher biological competition. Differences in microbial competition had little effect. Roots were equally colonized in the differing soil microflora in three management systems at the Rodale Farming Systems Trial. Invading an existing soil microbial community is the most difficult thing to achieve with a biocontrol organism. These data show that T-22 is the first to consistently do so.
A Phenotypic and Molecular Evaluation of Field-grown Trees Derived from Somatic Embryogenic Cultures
Authors: Vendrame Wagner A. , Sparks Darrell , Kochert Gary D. , Wetzstein Hazel Y.
Published: January 2019

Somatic embryogenic protocols have been developed for pecan, Carya illinoinensis (Wangenh.) C. Koch, in which high multiplication rates and efficient plant regeneration can be obtained. Regenerated plants were transferred into the field in 1995. Phenotypic and genetic comparisons were made of trees from two tissue culture lines to assess if plants derived from somatic embryogenic cultures maintain clonal fidelity and exhibit true-to-type characteristics. Genetic changes were examined using AFLP (Amplified Fragment Length Polymorphism) analyses. Shoot growth, leaf morphology, and the occurrence of scab (Cladosporium caryigenum) lesions and Phylloxera galls were evaluated. AFLP could readily detect differences between the tissue culture lines, which exhibited a higher number of polymorphic loci relative to comparisons within culture lines. Phenotypic characteristics differed between lines, but were generally consistent in trees within a culture line.
Implementing a Tomato Disease Forecast System in Northern New Jersey
Authors: Maletta M.H. , Cowgill W.P. , Tietjen W. , Johnston S.A. , Manning T. , Nitzsche P.
Published: January 2019

After 4 years of research trials with TOM-CAST, an early blight and anthracnose forecaster for tomatoes, forecast information was made available to northern New Jersey growers in 1997. Rutgers Cooperative Extension provided 20 tomato growers with information and training on using TOM-CAST to schedule fungicide applications. Rutgers Cooperative Extension set up and maintained six weather stations in a three-county area. Rutgers personnel downloaded weather data twice weekly from May to late October and generated and published disease severity values (DSV) by phone and fax. Growers obtained DSVs for their site from the nearest weather station(s) and used them to determine their spray schedule. A survey to determine grower use of and attitudes about the system were mailed in Oct.1997. Four growers used the system to schedule fungicide applications. Growers reported the following perceived advantages of using TOM-CAST: cost savings and savings to environment; disease forecasting being “the future” of disease management; knowing for sure when to spray. Growers reported the following perceived disadvantages: risk to crop; inconvenience of an irregular spray schedule; concern about other diseases. Growers who did not use the system in 1997 were queried about the reasons they did not use it and whether they would consider using TOM-CAST in 1998.
Evaluating Transgenic Apple for Resistance or Tolerance to Apple Replant Disease
Authors: Isutsa Dorcas , Merwin Ian , Brodie Bill
Published: January 2019

Apple replant disease (ARD) causes serious problems in most fruit-growing regions worldwide. It is associated with nematodes, fungi, bacteria, and other deleterious factors. Its symptoms range from severe stunting to death of replants in old orchards. We evaluated effects of antibacterial (cecropin-, attacin- and hen egg white lysozyme-encoding) and antifungal (chitinase-encoding) transgenics, obtained from the apple-rootstock breeding program at Geneva, N.Y., on ARD. Transgenics were tested in a composite soil collected from New York orchards with known replant problems. The ARD-infested field soil (FS) had ≈675 Pratylenchus penetrans (root-lesion nematodes, RLN) and ≈75 Xiphinema americanum (dagger nematodes) per liter pot; soil for controls was steam-pasteurized. Height, biomass, nematode vermiforms and eggs were recorded after ≈60 days under optimal growing conditions in the greenhouse. There was significant variation in growth and Pratylenchus counts among transgenics (P < 0.00), most of which were susceptible to ARD. However, endoparasitic RLN accounted for <50% of the variation in biomass, suggesting that other factors were important in affecting plants. Conversely, RLN significantly increased root necrosis (P < 0.00; R2

= 80%). Eggs were observed in diseased chitinase-encoding lines, probably because of low-gene expression. There was no significant difference in eggs among the lines (P ≤ 0.3). Apparently, good growth was inconsistent and due to confounding factors such as mild ARD. These results suggest that single-gene therapy and low-gene expression may not protect apple against ARD complex, instead gene-pyramiding and high-gene expression should be tested.
Effect of the Stages of Floral Development and Postharvest Temperatures to Flowering of Eremurus in Israel
Authors: Kamenetsky Rina
Published: January 2019

The influence of postharvest temperature on the flowering response of Eremurus was studied. The plants were harvested at four different stages of development and were separated into three groups. The first group was immediately exposed to 2 °C, the second group to 20 °C followed by 2 °C, and the third group to 20 °C followed by 32 °C and, subsequently, 2 °C. Scanning electron microscopy (SEM) was used for concurrent morphological analysis of floral development. Application of 2 °C to the plants in the initial stage of floral development caused plant destruction and death, while the same treatment applied at the stage of full differentiation promoted normal flowering. Temperatures of 20 °C and, especially, 32 °C, significantly improved flowering of the plants harvested in the early stages of florogenesis, whereas the same treatment applied to the plants harvested at the end of flower differentiation did not affect the flowering process. A developmental disorder, which we term “Interrupted Floral Development” (IFD), was observed only in the plants harvested when the racemes were fully differentiated. This was probably caused by the very high air and soil temperatures that prevail in Israel during the summer. The extent of floral differentiation has a determinant role in subsequent scape elongation and flowering.
Calcium Oxalate Cuticular Crystals in the Epidermis of Dracaena—A Taxonomic Feature of the Genus
Authors: Pennisi Svoboda V. , McConnell Dennis B.
Published: January 2019

The genus Dracaena has been placed in Agavaceae by most taxonomists. Recent work, however, has justified the placement in a separate family, Dracaenaceae. This study was initiated to examine the extracellular crystalline deposits in Dracaena and the possibility of this feature as a taxonomic trait of the genus. Fresh epidermal peels of five Dracaena species were observed under polarized light. Extracellular epidermal crystals were evident in all of them. The deposits were found between the cuticle and the outer primary epidermal cell wall. The crystal size varied from less than 1 μm to 5 μm along the long crystal axis. The size and quantity of the deposits varied between the species with largest and most numerous crystals in the cuticle of D. marginata and D. sanderiana. Dracaena deremensis, D. fragrans, and D. surculosa had smaller and less numerous crystals. The optical properties of the crystals were indicative of calcium oxalate monohydrate form which exhibited interference colors of second and third order. For comparison species of three members of Agavaceae were examined -Cordyline terminalis, Sansevieria trifasciata, and Yucca sp. No extracellular crystal deposits in the proximity of the epidermal wall were detected. Based on our observations, the genus Dracaena possessed an anatomical feature which could be used for identification. The existence of calcium oxalate crystals embedded in the cuticle was readily observable in fresh epidermal peels under polarized light.
Chill Requirements to Break Dormancy of Wisconsin Cranberry: Conventional Models may Not be Applicable
Authors: Workmaster Beth Ann A. , Palta Jiwan P.
Published: January 2019

Conventional chilling models developed primarily for deciduous fruit crops such as apple and peach are based on the accumulation of optimal chilling temperatures between ≈4 and 7 °C. Cranberry (Vaccinium macrocarpon) is a perennial evergreen woody vine that requires chilling temperatures to overcome its dormancy. Periodic collections of budded stems (uprights) from cranberry beds (cv. Stevens) in central Wisconsin throughout the fall and early winter were forced to determine when dormancy requirements were met in the field. For this purpose excised uprights were placed in deionized water in test tubes at 24 °C and 16-h day (cool-white fluorescent). In both 1996 and 1997 it was observed that uprights were able to break bud and grow in late fall and early winter only after experiencing (in addition to chilling) a prolonged period of temperatures slightly below freezing. As an evergreen plant, cranberry may be receiving critical environmental cues at its leaves. Additionally, the existence of the native cranberry plant in harsh winter environments may have resulted in the need for freezing temperatures during dormancy to ensure survival.
Ripening Stages of Cranberry Fruit Have a Dramatic Influence on Its Postharvest Shelflife: Physiological and Morphological Explanation
Authors: Özgen Mustafa , Smith Jonathan D. , Workmaster Beth Ann A. , Palta Jiwan P.
Published: January 2019

Cranberries ripen in late fall. The fruit develops color in the outer two cell layers in response to low temperatures and incident light. Berries at the top of the canopy generally develop full red color, whereas fruits lower in the canopy (especially under dense canopies) can remain white even at harvest time. This is especially true for Wisconsin-grown cranberries. Wet-harvested cranberries are stored for 1 to 2 months and sold at Thanksgiving and Christmas time. We investigated if the storage quality of fruit is dependent on ripening state. Wet-harvested fruits were sorted into four different ripening stages and rated for quality after 4 and 7 weeks of storage. In addition, fruit CO2 and ethylene production, as well as anthocyanin content, were measured after 4 weeks of storage. The amount of rotten fruit among red, light red, blush, and white were 12%, 14%, 23%, 38% respectively. Thus, white fruits had three times greater incidence of rot than the red fruits. Although the ethylene production by various categories of fruit was nearly same, white fruits had 70% higher respiration than red fruits. We also found that as the fruit developed color cuticle thickness increased. For example, cuticle thickness averaged 1.6 μm for white fruit and 2.3 μm for red fruit. In addition, the calyx end opening of red fruit was impregnated with more wax than white fruit. Furthermore, a compact cell layer accumulated anthocyanin under the calyx opening in red fruit only. Our studies suggest that white berries have poor shelf-life as compare to red fruit because: i) white fruits have higher respiration rates, ii) thicker cuticle and wax accumulation (especially at the calyx end) on red fruits retard the entry of microorganisms into the fruits during wet harvest.