bluuebunny/crossref_metadata_2025 huggingface dataset:
(224) In Situ N Monitoring for Safe Leafy Vegetables using Quick and Advanced Tools
Authors: Ma Chin H. , Palada Manuel C.
Published: February 2019

High levels of N fertilizers are generally applied in intensive leafy vegetable production in the peri-urban agriculture of Southeast Asia. This study was conducted to develop a simple and rapid method of determining nitrate-N accumulation in selected leafy vegetables. Five leafy vegetables, including amaranth (Amaranthus tricolor), kangkong (Ipomoea aquatica), Ethiopian kale (Brassica carinata), choysum (Brassica campestris sp. parachinensis), and leafy lettuce (Lactuca sativa) were grown on raised beds in 32-mesh nethouse in randomized complete-block design with four replications. The crops were fertilized with eight N levels: 0, 50, 100, 150, 200, 250, 300, and 350 kg·ha-1 in three splits. At harvest, nitrate contents were determined in tissue sap of fully expanded leaf blades, petioles and whole plant using a Cardy nitrate meter. Chlorophyll content readings were also measured on the same leaf using a chlorophyll meter. Nitrate accumulations varied with vegetable species. Significant correlations (P< 0.001) existed between N fertilizer rate and nitrate content as well as leaf chlorophyll and yield. Using N application rate of 200 kg·ha-1, nitrate accumulation in Ethiopian kale was highest (7000 ppm), followed by kangkong (4000 ppm), amaranth (3500 ppm), and leafy lettuce (1200 ppm). The correlation between leaf chlorophyll meter reading (LCMR) and nitrate content was also significant (P< 0.001), suggesting the feasibility of using Cardy nitrate meter test and LCMR for monitoring production of low-nitrate and safe vegetables. The Cardy meter was also sensitive in detecting soil nitrate-N below 20 ppm and is a rapid and reliable alternative to conventional distillation method.
(437) Application of Differential Thermal Analysis to Study Freezing Behavior and Supercooling in Plants
Authors: Shirazi A.M. , Thierry M.V.
Published: February 2019

Survival of temperate plants is often dependent upon their resistance or ability to tolerate low temperatures. Differential thermal analysis (DTA) has been employed to explore the freezing characteristics of plants and other organisms. However, there appears to be a need for further studies to better understand the physiology of freezing and its significance as related to supercooling. Methods employing thermocouples, differential wiring, and digital data acquisition boards allow detection of very small exothermic responses (about 0.025 °C). This study reports on techniques and apparatus for using DTA as well as results obtained on various plant tissues. When Fagus grandifolia (American beech) was compared to Fagus sylvatica (European beech), it exhibited both a lower high temperature (HT) and low temperature (LT) exotherm that correlated with lower stem tissue water content during September to May. The DTA on Acer pseudosieboldianum (Korean maple) from a higher elevation showed lower LT exotherm in stem tissues when compared to lower elevation samples. Incubation of Cornus amomum, Cornus obliqua, and Larix gmelinii var. olgensis stem tissue with d-H20 for 20 hours resulted in an induction of LT exotherm at a significantly higher temperature than a normal LT exotherm. This phenomenon was attributed to the bark tissue in Larix gmelinii var. olgensis. Sucrose and glycerol exotherm profiles exhibited lower exotherm temperatures. In a companion study, we used thermal analysis (non-differential) to study supercooling in [Homadaula anisocentra(Mimosa webworm)] and a single exotherm event was detected. New technology provides a great deal of flexibility in the method of evaluation of exothermic responses in plants and other organisms.
(285) DNA Fingerprinting of Flowering Dogwood Cultivars
Authors: Smith Naomi R. , Trigiano Robert N.
Published: February 2019

Flowering dogwood (Cornus florida L.) is an important tree of forests and urban landscapes in the eastern United States. Currently, there are over 100 cultivars of flowering dogwood commercially available. An identification process based on genotype would be of use to researchers, breeders, and nurserymen, as many cultivars are similar phenotypically. Molecular markers offer a promising way of definitively identifying flowering dogwood cultivars. Amplified fragment length polymorphism (AFLP) is a technique that can be used to generate DNA fingerprints. DNA was isolated from leaves of 17 common cultivars of dogwood and AFLP fingerprints were generated by a Beckman Coulter CEQ™ 8000. Fingerprints were converted to binary data and verified manually. Two drafts of a cultivar identification key were generated based on the corrected, verified binary data and cultivar-specific peaks. Six primer combinations were used to construct all keys and were tested with seven unknown dogwood cultivar samples. Six unknown samples were correctly identified using the keys. Only one unknown, `Cherokee Brave', was unidentifiable with any key. In all cases, some intracultivar variation was observed. A similarity index was calculated and visualized with a tree of genetic relatedness using NTSYSpc. Intracultivar variation was observed in the similarity index as well. This database for cultivar-specific molecular markers will serve as a starting point to which other cultivars can be added and also can be used in breeding applications, patent application and other projects, such as mapping the C. florida genome.
(290) Increased Tolerance to Dark, Cold Storage in Double Transgenic Plants Expressing FAD7 and IPT Genes under the Control of a Cold-inducible Promoter
Authors: Khodakovskaya Mariya , McAvoy Richard , Wu Hao , Peters Jeanne , Li Yi
Published: February 2019

Chill injury and leaf senescence occur in plants held in prolonged cold, dark storage. To increase tolerance to these conditions, Nicotiana alata and N. tabacum were transformed with either the FAD7 or IPT genes under the control of a cold-inducible promoter (cor15a). FAD7 encodes for omega-3-fatty acid desaturase and was used to resist cold-stress. IPT encodes the cytokinin-pathway enzyme isopentenyl transferase and was used to delay senescence. Independent FAD7 and IPT lines were crossed to produce double transgenic seed. Seedlings from single transgenic (cor15a-IPT or cor15a-FAD7) lines, double transgenic lines, and the wild-type were exposed to prolonged cold, dark conditions. After 3 months in the dark at 2 °C, survival of independent double transgenic N. tabacum lines ranged up to 80% to 90%. However only 40% of FAD7 seedlings survived, 10% of IPT seedlings survived, and no wild-type plants survived. Double transgenic N. alata seedlings average 90% survival under similar conditions and RT-PCR revealed expression of both the IPT and FAD7 genes. Omega-3-FAD enzyme activity increases desaturation in chloroplast membrane fatty acids. When exposed to prolonged cold, the molecular fraction of polyunsaturated fatty acids (18:3 and 16:3) in leaves of wild-type N. alata decreased while monounsaturated (16:1 and 18:1) and saturated fatty acid species (16:0 and 18:0) increased dramatically. In double transgenic N. alata lines exposed to prolonged cold, the molecular fraction of 18:3 and 16:3 increased, while the 16:0 and 18:0 species decreased dramatically compared to nonchilled double transgenic plants.
(441) Evaluation of Three Grafting Methods for Propagating Soursop (Annona muricata L.) in the Dry Tropic Region of Mexico
Authors: Gonzalez Juan Manuel González , Juarez Francisco Radillo , Tene Marcelino Bazan , Ramos Juan Carlos González
Published: February 2019

Soursop (Annonamuricata L.) is reproduced by seeds from `Criollo' cultivars in Mexico. The replication of desirable agronomic traits is difficult when selected plants are from sexual reproduction. The heterogeneity of plants is observed as taller trees, irregular fresh fruit yield, variable fruit quality, different insect pests, disease susceptibilities, and lower number of plants per hectare. There is an extended time period for recovering investments and commericialization problems due to fruit quality and price. Vegetative propagation is an alternative for reducing the heterogeneity of soursop trees. Three grafting methods were evaluated for propagating soursop in the dry tropic region of Colima, Mexico: 1) splice side graft; 2) wedge graft; and 3) bud graft. The experiment was carried out on the Tecoman Campus of the Universidad de Colima. Rootstocks were from 8-month-old healthy plants, 1-m tall and 1-cm diameter, obtained from `Criollo' seedlings, and the scions were obtained from a healthy 10-year-old `Sin Fibra' donor tree. This donor tree was selected for its excellent agronomic traits and fruit yield. Vigorous and terminal scions were used, disinfected with fungicide, and used the same day of excision. The experiment was distributed under a completely randomized design. Splice side grafting had 67% success after 60 days, while wedge grafting and bud grafting had 0% success.
(443) International Conference on Vegetables: ICV–2002
Authors: Nath Prem , Velu Sundari
Published: February 2019

In a world that produces enough food for everyone, about 800 million people in the developing world do not have enough to eat. The important challenge facing agriculture in the new millennium is to eliminate chronic hunger. Safe and better quality food is equally important to ensure that people not only have sufficient energy but also the nutrients necessary for adequate productive lives. In order to release the pressure on cereals as well as to improve human nutrition through consumption of the other nutritious crops, diversification in cropping patterns provides better options, and horticultural crops, including vegetables with their wide adoption and providers of important nutrients, offer promise for the future. In this spirit and in the wake of the present global call for eliminating food and nutritional insecurity, the technologists, entrepreneurs, policy-makers and those interested in agriculture were invited to participate and contribute to fruitful discussion at the International Conference on Vegetables (ICV–2002), which was held 11–14 Nov. 2002 in Bangalore, India. About 700 participants from 37 countries across the globe participated in the conference, and a total of 621 papers were presented. The ICV–2002 addressed 13 theme areas, which included vegetable improvement in production, protection, underutilized vegetables, postharvest management, developmental policies and programs, marketing and trade including WTO policies and programs, and, finally, technical cooperation among developing countries. The salient recommendations of the ICV–2002 will be presented.
(125) Response of Six Begonia Species to Different Substrate pH
Authors: Jeong Ka Yeon , Pasian Claudio , Tay David
Published: February 2019

Substrate pH of soilless media directly affects nutrient availability. Limited information about the effect of substrate pH on growth of begonia species (not cultivated hybrids) was found in the literature. The objective of this study was to evaluate the effect of substrate pH on the growth and quality of six begonia species grown from June to Aug. 2004. The targeted pH ranges (<4.5, 4.5∼5.0, 5.0∼5.5, 5.5∼6.0, 6.0∼6.5, 6.5∼7.0, and over 7.0) of the peat-based substrates were obtained by adding seven different amounts of dolomitic hydrated lime: 0, 1.0, 1.3, 1.6, 2.0, 2.4, and 2.6 kg·m3. Begonia albopicta, B. cucullata var. cucullata, B. echinosepala var. elongatifolia, B. holtonis, B. fuchsioides (red), and B. fuchsioides (pink), were propagated by stem cuttings, and then transplanted into plastic containers. This experiment was a factorial experiment arranged in a randomized complete-block design. The pH was monitored weekly using the pour-through method and adjusted accordingly by adding flowable lime or a mild sulfuric acid solution. The pH values were averaged for each treatment of each species. There were significant differences between species in the inflorescence number and SPAD readings, but no interaction between species and substrate pH was found. Stem length, leaf area, and dry weight of each plant were significantly affected by species and substrate pH. B. albopicta performed best at substrate pH of 5.6 and 6.0, showing no symptoms of phytotoxicity. B. cucullata, above substrate pH 6.0, and B. holtonis at pH 5.0 and 5.6 had the highest vegetative growth and plant quality. Plant mortality was observed for B. cucullata and B. fuchsioides (red) at pH below 4.4 and 5.3, respectively.
(133) Influence of Two Types of Fertilizers on the Growth and Development of Tissue-cultured Daylilies Transferred to the Greenhouse
Authors: Carter Johnny , Palmer Diondre , Chen Lianghong
Published: February 2019

During Summer 2004, a study was conducted to determine the effect of two types of fertilizers on the growth and development of tissue-cultured daylilies transferred to the greenhouse. Peters 20–20–20 water-soluble fertilizer and a slow-release fertilizer were the two fertilizers evaluated. Peters 20–20–20 fertilizer was used at 0 (control), 50, 100, and 200 mg·L–1 rates. The slow release fertilizer was used at 2.5 g per 10.2 cm pot. Each treatment was replicated four times in a randomized complete-block design. After 6 weeks of growth, the results showed that, when compared to the control, all treatments except for 200 mg·L–1 caused a significant increase in root growth. Shoot growth was significantly increased by the 100 mg·L–1 treatment, while the 200 mg·L–1 and slow-release treatments suppressed shoot growth. Similar to root and shoot growth, the 100 mg·L–1 treatment caused a significant increase in fresh weight, while the 200 mg·L–1 and slow-release treatments caused a reduction. These results imply that the 100 mg·L–1 Peters 20–20–20 fertilizer treatment is the best treatment for maximum growth and development of tissue-cultured daylilies transferred to the greenhouse.
(254) Molecular Characterization of Doubled Haploid and Conventional Onion Lines using AFLPs and SSRs
Authors: Walker Ryan , Pike Leonard , Menz Monica , Yoo Kil Sun , Kim Sung Gil
Published: February 2019

Onions suffer from severe inbreeding depression, which has prevented the creation of homozygous inbreds in breeding programs. The creation of doubled haploid (DH) lines in onion is an anomaly, and provides a unique opportunity to study both how these lines would perform in a breeding program and why they do not exhibit more inbreeding depression. Seven DH lines were developed at Texas A&M University from five different short-day F1 and F2 populations. Five equivalent conventional inbred lines, breeding lines developed from the same parents as the DH lines, have been identified from the onion-breeding program. The DH lines, the conventional inbred lines, and their parents have been analyzed using SSR and AFLP markers. SSR markers yielded a polymorphism rate of 55% vs. 3% with the AFLPs. Analysis has shown remnant heterozygosity both in the parental lines and in the conventional inbreds and has confirmed the uniformity of the DH lines. Genetic similarity estimates have been calculated using the molecular data to determine the suitability of comparing the yield heterosis of crosses between the conventional lines and the DH lines in a diallele analysis.
(256) Evaluation of 25 Varieties of Race 3 Bacterial Spot Resistant Bell Peppers
Authors: Nagata Russell T. , Pernezny Kenneth L. , Parmenter Darrin M. , McAvoy Eugene , Cushman Kent E.
Published: February 2019

Twenty-five varieties of bell peppers (Capsicum annuum) were transplanted in commercial pepper fields in Immokalee and Delray Beach, Fla., to evaluate horticultural characteristics and resistance to race 3 bacterial spot of peppers caused by Xanthomonascampestris pv. vesicatoria. All cultural and management procedures were based on commercial best management practices. Eighty to 90% of marketable fruits had three or four lobes. Total marketable fruit yield from three harvests ranged from 4596 to 7089 kg·ha-1 and marketable fruit number ranged from 20,571 to 31,224 fruit/ha. Most fruit were slightly elongated with length to diameter ratios between 1.1 and 1.2. Seminis 7602 had a ratio of one, while lines ACR 252, PRO2R-3, and PR99R-16 had ratios of 1.40, 1.36, and 1.28, respectively. Significant differences were observed for fruit wall thickness, with those grown in Delray Beach having thicker fruit walls that averaged 7.5 mm vs. 5.3 mm for the Immokalee site. Bacterial spot infection at both sites did not affect yield, due to late natural infection of the field. Susceptible control `Jupiter' had a mean foliage disease incident rating of 26% after the final harvest and was surpassed only by 7682 and 8328 from Enza. The most resistant lines with disease ratings of <3% were 5776, 7141, and 8302 from Seminis, and Telstar from Hazera.
(466) Comparison of Autumnberry and Cornelian Cherry Antioxidant Potential with that of Well-known Fruit Crops
Authors: Ozgen Mustafa , Tulio Artemio Z. , Gazula Aparna , Scheerens Joseph C. , Reese R. Neil , Miller A. Raymond , Wright Shawn R. , Black Brent L. , Fordham Ingrid M.
Published: February 2019

Autumnberry (Elaeagnus umbellata, “A”) and cornelian cherry (Cornusmas, “CC”) genotypes were examined for mineral composition, anthocyanin, phenolic and tannin contents, antioxidant characteristics and levels of individual phenolic compounds via GC-MS. Values were compared with those of 58 cultivars of blackberries (“B”), black raspberries (“BR”), cranberries (“C”), elderberries (“E”), grapes (“G”), red raspberries (“RR”) and strawberries (“S”). The phenolic content of “CC” (6955 μg·gfw-1) was greater than 2× that of “B”, “BR” and “E”. Phenolic contents of “A” samples (1058-1776 μg·gfw-1) were similar to those of “RR”, red “G” and “S”. Anthocyanin levels in “CC” (270 μg·gfw-1) resembled those in “C”. “A” did not contain anthocyanins. Fruit of “CC” and “A” possessed high tannin levels (9291 μg·gfw-1 and 1410–5403 μg·gfw-1, respectively) and exhibited high antioxidant potential (μmol·gfw-1 trolox equiv.). DPPH and FRAP values of “CC” (72.1 and 94.9, respectively) were greater than 2× those of “BR”. DPPH values of “A” (23.9–56.2) were ≥ values for “BR”, whereas “A” FRAP values (13.3–34.0) were similar to those of “B” and “RR”. However, the lipid-soluble antioxidant potential of lycopene-rich “A” was substantial. Levels of individual compounds varied among cultivars. Ca and Mg contents of “A” were less than those found in “CC” and “BR”. Other mineral levels were comparable.
(471) Application of Mustard and Hop Extract Agents Mixed with Sucrose Fatty Acid Esters as a Food Preservative for Fresh-cut Vegetables
Authors: Hamanaka Daisuke , Watakabe Takashi , Kitano Kazuyuki , Izumi Hidemi
Published: February 2019

Cabbage shreds and cucumber slices were dipped in water or solutions of mustard extract agent (WASAOURO®, Mitsubishi-Kagaku Foods Corp.) and hop extract agent (HOPREX®, Mitsubishi-Kagaku Foods Corp.) with or without sucrose fatty acid esters (SE; Mitsubishi-Kagaku Foods Corp.) and stored in MA packaging at 10 °C. With cabbage shreds, treatment with mustard extract agent reduced the depletion of O2 and accumulation of CO2 and ethylene in MA packaging and the reduction was greater when mixed with SE. Treatment with the combination of mustard and hop extract agents with SE also had suppressing effects on respiration and ethylene production of cabbage shreds throughout the MA storage period. Counts of mesophilic aerobic bacteria and coliforms were 0.3 to 0.7 logs lower in cabbage shreds treated with mustard extract agent with or without SE than with the water-dipped control for the first 2 days of storage at 10 °C. However, mustard extract agent stimulated the growth of lactic acid bacteria. When hop extract agent was combined with mustard extract agent with SE, counts of mesophilic aerobic bacteria, coliforms, and lactic acid bacteria on treated cabbage shreds were reduced by 0.8, 1.6, and 2.6 logs, respectively, relative to control samples after 5 days of storage. Cucumber slices treated with mustard extract agent with or without SE accelerated respiration and ethylene production and did not retard any bacterial growth during MA storage at 10 °C.
Weed Control in Organic Vegetable Production: The Use of Sweet Corn Transplants and Vinegar
Authors: Markhart Albert H. , Harr Milton J. , Burkhouse Paul
Published: February 2019

Weed control in organic vegetable production is a major challenge. During Summer 2004, we conducted field trials to manage weeds in organic sweet corn, carrots and onions. In sweet corn, we evaluated the efficacy of transplanting greenhouse-grown sweet corn seedlings. In carrots and onions, we tested vinegar and several concentrations of acetic acid. Studies were conducted in southwestern Minnesota at the Lamberton Research and Outreach Center and in eastern Minnesota at Foxtail Farm in Shaefer. Ten-day-old corn transplants were effective at both locations. Stand establishment was greater, less tillage was needed, and yield was greater than in the seeded plots. Straight vinegar was not very effective in controlling weed populations. Although there was greater damage to broadleaf weeds than grasses, straight vinegar did not reduce the need for tillage. Although 10% to 20% acetic acid did provide better weed control, it significantly damaged carrot and onion seedlings. These results suggest that using sweet corn transplants is time and cost effective for small acreage sweet corn production such as CSAs. Vinegar and acetic acid are problematic. Nonselectivity, potential danger in handling, and poor control at low concentrations were all considered significant disadvantages.
Deficit Irrigation and Plant Population Effects on Leaf Quality and Yield of Spinach
Authors: Leskovar Daniel I. , Piccinni Giovanni , Moore Darrin
Published: February 2019

A two-year experiment was conducted to determine yield, water use efficiency, and leaf quality responses to deficit irrigation and plant population of spinach (Spinacia oleracea L.). Three irrigation regimes were imposed with a center pivot system, 100%, 75%, and 50% crop evapotranspiration rates (ETc). Spinach seeds were planted on 11 Nov. 2003 at three plant populations: 494 (P-1), 618 (P-2), and 741 (P-3) thousand seeds/ha on cvs. DMC 16 and ASR 157, and on 15 Oct. 2004 at four plant populations: 655, 815, 988, and 1149 thousand seeds/ha on cv. DMC 16. Harvests were done on 3 Mar. 2004 and 26 Jan. 2005. In the first season, marketable yield was not reduced by deficit irrigation, but water use efficiency was significantly higher for 50% ETc compared to 100% ETc. The cv. DMC 16 had a significantly lower percentage of stem weight than ASR 157 (8.3 vs. 16.4%). The cv. ASR 157 had an excess of stem weight at 100% and 75% ETc compared to 50% ETc at P-1, but similar at P-2 and P-3. The cv. DMC 16 had a trend of reduced stem weight for P3 at 50% ETc. In the second season, marketable yield was reduced by deficit irrigation. However, water use efficiency was significantly higher for 50% ETc compared to 100% ETc, but similar to 75% ETc. Deficit irrigation also decreased the percentage of stem weight. Despite a slight increase in the percentage of of yellow leaves, but not in percentage of of stem weight, marketable yield and water use efficiency were significantly higher at 1149 thousand seeds/ha. This study showed that deficit irrigation in combination with increased plant population has the potential to increase yield and water savings, without adversely affecting leaf quality.
In Situ Probes for Direct Measurement of Substrate Soluble Salts: Effects of Substrate Moisture Content and Fertilizer Concentration
Authors: Scoggins Holly L. , van Iersel Marc W.
Published: February 2019

Several probes have been been recently developed that can be inserted directly into the growing medium of container-grown crops to get electrical conductivity (EC) or pH measurements. However, for many floriculture and greenhouse crops, EC interpretation ranges are based on substrate solution extraction methods such as the 1:2 v/v dilution, saturated media extract (SME), and more recently, the pour-through. We tested the sensitivity and accuracy of four in situ EC probes at a range of substrate moisture content and fertilizer concentrations. We also compared results from in situ probes with currently used methods of EC measurement. Concerning the effects of substrate volumetric water content (VWC) on the in situ probes, our results indicate little differences exist among probes when VWC exceeds 0.50, though drier substrates yielded differences depending on the measurement method. The SigmaProbe and W.E.T Probe measure the EC of the pore water specifically and show a decrease in EC with increasing water content, as the fertilizer ions in the pore water becomes more diluted as VWC increases. Results with the Hanna and FieldScout probes increased with increasing water content as the added water helps conduct the current of these meters. The EC measured with the various in situ probes differed slightly among the probes, but was highly and positively correlated with all three of the solution extraction methods over the range of fertilizer concentrations. It would be possible to convert substrate EC guidelines that have been established for any of the laboratory methods for use with the in situ probes, though our results indicate the substrate VMC must be above 0.35 for the interpretation to be valid.
Selenium Concentration of Broccoli Inbreds and Hybrids Is Largely Influenced by Environment
Authors: Hale Anna L. , Farnham Mark W. , Grusak Michael A. , Finley John W.
Published: February 2019

Broccoli(Brassica oleracea L. Italica Group) can contain high levels of selenium (Se) in the form of selenium methyl selenocystine. This is a relatively unique Se compound that is found in certain plant species that accumulate this element. Several recent studies have shown that high Se broccoli can inhibit the development of certain cancers (e.g., colon and mammary) in rodents and this has led to increasing interest in broccoli as a vegetable that confers chemoprotective effects. The objective of this research was to determine the relative importance of genotype vs. environment in the expression of Se concentration in broccoli heads. A set of 15 broccoli inbreds and a set of 20 hybrids were evaluated in three different environments. Mature heads were harvested from plots, heads were dried and ground, and Se concentration was determined on a dry weight basis. Overall, Se levels measured in this study were low to moderate, typically ranging from about 20 to more than 100 ng/gdw of Se per head. For both inbreds and hybrids, the effect of environment on Se head concentration was highly significant and more than 10 times greater than the effect of genotype. When analyzed across all three environments, the genotypic effect on Se concentration was significant for hybrids only. However, when assessed for individual environments, the genotypic effect was significant in just one of three of the test environments with both inbreds and hybrids. Results indicate that genetic modification of broccoli to increase selenium concentration of heads will likely be difficult to achieve.
Temperature Regulates Flowering of Two Odontioda Orchid Hybrids
Authors: Blanchard Matthew G. , Runkle Erik S.
Published: February 2019

The production value of potted orchids has increased by 155% in the past decade, and they are now the second-most valuable potted flowering plant in the United States. Scheduling orchids to flower on specific dates requires knowledge of the environmental parameters that regulate flower induction. However, the flowering requirements of the vast majority of orchid species and hybrids have not been well described. Odontioda is a cool-growing, epiphytic genus originating from the Andes Mountains of South America, and several hybrids are commercially grown for their bright-colored flowers and compact habit. We quantified the promotion of inflorescence initiation and time from visible inflorescence (VI) to anthesis at constant and fluctuating day/night temperatures. Odontioda George McMahon `Fortuna' and Lovely Penguin `Emperor' were grown at constant temperatures of 14, 17, 20, 23, 26, or 29 °C, and day/night (12 h/12 h) temperatures of 20/14, 23/17, 26/14, 26/20, 29/23, or 29/17 °C. Plants were grown in glass greenhouses under a 12-h photoperiod, and shading was provided so that the maximum instantaneous irradiance was ≤300 μmol·m-2·s-1. After 6 weeks at the various temperature setpoints, heat stress symptoms were observed on plants grown at 26, 29, 26/14, 26/20, 29/23, and 29/17 °C. After 14 weeks, ≥60% of both hybrids had VI when grown at 14, 17, 20, or 20/14 °C. Data for time from VI to anthesis were converted to a rate and a thermal-time model relating temperature with inflorescence development was developed. This information could be used by commercial orchid growers to schedule flowering Odontioda orchids for specific market dates.
Inheritance of Flowering without Vernalization in Seed-propagated Lilium formosanum Wallace
Authors: Zlesak David C. , Anderson Neil O.
Published: February 2019

A majority of commercial Lilium hybrids and species do not flower the first year from seed or scales due to an obligate vernalization requirement. The Formosa lily (L. formosanum) is a unique species within the genus Lilium because some genotypes flower from seed the first year without vernalization. The objective of this study is to determine the inheritance of stem emergence, which culminates in flowering, in seed-propagated families without vernalization. Nine L. formosanum genotypes, selected from six populations for obligate or non-obligate vernalization for flowering, were intermated to generate 23 families with 104 seedlings per family. Families were grown in a randomized complete-block design at 21 °C (day/night) and data collected were seedling mortality, stem emergence or rosetting without vernalization, and weeks to emergence. At the end of 44 weeks, rosetted genotypes were vernalized for 8 weeks (4 °C); 100% emerged. We propose this trait is controlled by two genes. For flowering without vernalization to occur, there needs to be at least one dominant allele at one of the loci. Locus Ver2 has less penetrance than Ver1. Families segregating for dominant alleles at both Ver1 and Ver2 emerged sooner (34.2 weeks) than those segregating for a dominant allele at only Ver1 (36.1 weeks) or Ver2 (37.6 weeks). Identification of these genes can aid in the development of uniform, fast-flowering L. formosanum hybrids as well as aid in the introgression of this trait into standard commercial lily classes.
Comparison of Gamete Selection for Heat Stress and Cool Temperature Tolerance in Phalaenopsis
Authors: Blischak Leslie A. , Veilleux Richard E.
Published: February 2019

Gamete selection was examined as a breeding tool in developing Phalaenopsis hybrids that are more extreme temperature tolerant. Four pairs of hybrid cultivars were cross-pollinated, and then exposed to two temperature extremes, 30 °C/25 °C and 14 °C/9 °C, during initial pollen tube growth. One of each pollinated orchid cultivar was placed in either of two growth chambers and exposed to an 11-hour photoperiod with an irradiance of 180 mmol·m-2·s-1 and a relative humidity of 70% for 3–7 days. The capsules were collected after 150 days. Protocorm development was evaluated after 73 days on a thermogradient table ranging from 10 to 30 °C. For cold-pollinated seeds, protocorm development was optimum at 22 and 28 °C (means of 290 and 250 protocorms per plate, respectively), whereas the greatest protocorm development for warm-pollinated seeds occurred at 20 °C (103 protocorms/plate). Protocorms were evaluated for leaf and root formation 125 days after initial plating. Transfer to warm or cold incubators occurred as seedlings matured. One year after the initial plating, seedlings were evaluated on the following criteria: weight, number of leaves, leaf width, leaf length, leaf area, number of roots, and root length. The pollination treatment significantly affected the number of roots per seedling, whereas table position during germination significantly affected weight. The weight, number of leaves, and average root length were significantly affected by the pollination treatment and incubator interaction. The interaction between pollination treatment and table position significantly affected weight, number of roots, and average root length. Additional replication is required to confirm the greater germinability of cold-pollinated seed at higher temperatures.
Transgenic Grapevines Resistant to Pierce's Disease
Authors: Gray D. J. , Li Z. T. , Hopkins D. L. , Dutt M. , Dhekney S. A. , Van Aman M. M. , Tattersall J. , Kelley K. T.
Published: February 2019

Pierce's disease (PD), caused by the xylem-limited bacterium Xylella fastidiosa, is endemic to the coastal plain of the southeastern United States. Although native southern grapevines are tolerant to X. fastidiosa, all varieties of Vitisvinifera grown in the region will succumb to PD. Genetic transformation to add disease resistance genes, while not disturbing desirable phenotypic characters, holds promise for expanding the southeastern U.S. grape industry by allowing use of established fruit and wine varieties. We utilize embryogenic cell cultures and Agrobacterium strain EHA105 to refine transformation systems for Vitis species and hybrids. V. vinifera`Thompson Seedless' is employed as a model variety to test various transgenes for disease resistance, since as many as 150 independent transgenic plant lines routinely are produced from 1 g of embryogenic culture material. Transgenic plants are stringently screened for PD resistance in greenhouses by mechanical inoculation with X. fastidiosa. Transgenic plants are compared with both susceptible and resistant control plants by assessing typical PD symptom development and by assaying bacterial populations in xylem sap over time. Using these procedures, nine putative PD resistance genes have been inserted into grapevine and over 900 unique transgenic lines have been evaluated. A range of susceptible-to-resistant responses has been catalogued. Thus far, the best construct for PD resistance contains a grape codon-optimized hybrid lytic peptide gene in a high-performance bi-directional 35S promoter complex. Certain transgenic plant lines containing this construct exhibit better resistance than that of resistant control vines.
DNA Methylation Polymorphisms in Somaclonal-derived Cultivars of Ornamental Aroids
Authors: Fang Jinggui , Chao Chih Cheng , Henny Richard J. , Chen Jianjun
Published: February 2019

Plant tissue culture can induce a variety of genetic and epigenetic changes in regenerated plantlets, a phenomenon known as somaclonal variation. Such variation has been widely used in the ornamental foliage plant industry as a source for selection of new cultivars. In ornamental aroids alone, at least 63 somaclonal-derived cultivars have been released. In addition to morphological differences, many somaclonal aroid cultivars can be distinguished by amplified fragment length polymorphism (AFLP) analysis. However, a few cultivars have no detectable polymorphisms with their parents or close relatives by AFLP fingerprints. It is postulated that DNA methylation may be involved in the morphological changes of these cultivars. In this study, methylation-sensitive amplification polymorphism (MSAP) technique was used to study DNA methylation in selected somaclonal cultivars of Alocasia, Aglaonema, Anthurium, Dieffenbachia, Philodendron, and Syngonium. Results showed that polymorphisms were detected in the somaclonal cultivars, suggesting that DNA methylation polymorphisms may associate with tissue culture-induced mutation in ornamental aroids. This is the first study of methylation variation in somaclonal variants of ornamental foliage plants. The results clearly demonstrate that the MSAP technique is highly efficient in detecting DNA methylation events in somaclonal-derived cultivars.
Miscanthus sinensis and Panicum virgatum Competition Study
Authors: Meyer Mary Hockenberry , Paul Joe
Published: February 2019

Many different vegetatively propagated cultivars of Miscanthus sinensis Anderss. are popular ornamental grasses sold at garden centers and nurseries. Large stands of the “wild type” or species (not ornamental cultivars) of this grass have self-seeded near Asheville, N.C.; Valley Forge, Pa.; and Washington, D.C. In order to document the competitive ability of this self-seeded naturalized species, a greenhouse competition study was conducted with Panicum virgatum L. `Forestburg' (P), switchgrass, and several non-native, naturalized biotypes of Miscanthus sinensis (M) grown from seed collected from the above locations. Seedlings were transplanted into #1 (2.88 L) containers in nine different planting arrangements: 2M; 4M; 8M; 2M2P; 4M4P; 8M8P; 2P; 4P; 8P, and grown for 15 weeks. Growth measurements were taken during the 15 weeks. At harvest, shoot and root dry weights were calculated. Panicum had significantly larger root (0.50 g vs. 6.00 g) and shoot (6.96 g vs. 2.3 g) biomass, respectively, than Miscanthus. Intraspecific competition in monocultures was significantly higher for Panicum than Miscanthus. Panicum showed higher competitive ability than all Miscanthus biotypes, with one exception: root dry weights of one Pennsylvania biotype. Panicum increased in dry weight at the expense of Miscanthus. Panicum dominated Miscanthus during the 15 weeks and, in this study, proved to be a better competitor than Miscanthus. Miscanthus and Panicum did not fully share the common limiting resources and they showed partial resource complementarity. Miscanthus biotype variation was evident; the highest dry weights were from a Pennsylvania biotype and the smallest weights were from a Washington, D.C., biotype.
Exploratory Factorial for Nutrient and Water Use in Liquid Culture Micropropagation of Diploid and Tetraploid Daylily (Hemerocallis sp.)
Authors: Adelberg Jeffrey , Delgado Maria , Tomkins Jeffery
Published: February 2019

Two tetraploid and two diploid varieties of daylily were micropropagated on a shaker in MS liquid medium containing high and low sugar levels (3% and 6% sucrose), 2 BA levels (0.32 and 3.2 μm), at two densities (57 and 171 explants/L), in the presence (0.32 μm) and absence of ancymidol. Biomass and media use were partitioned for the four genotypes and 32 cultural conditions with three replications (4 × 2 × 2 × 2 × 2 × 3). Genotype greatly effected f resh weight, dry weight, media, sugar and water use, but ploidy had little effect. Vessels at high density (171 explants/L) produced 1.8× more fresh weight, 1.4× more dry weight, used 1.6× more media and sugar than low density (57 explants/L). Plants from low density were 1.7× larger, 2× greater dry weight, and used 2× more sugar and media, than from high-density culture (per explant). Doubling the initial sugar level increased dry weight and sugar use 1.3×. There was a linear relation between sugar residual and percentage of dry weight (R2 = 0.55, P < 0.0001), where a 1% increase in °Brix raised percentage of dry weight 1.8 units over the range of 9% to 22%. Ancymidol and BA had less effect on plant size, sugar and media use than genotype or plant density. Greenhouse survival was reduced by including ancymidol (90% to 30%) and increased BA concentration (85% to 35%). Lab plant density and initial sugar concentration had no apparent effect on greenhouse growth. `Barbara Mitchell' had greatest mass, used more sugar and media than the other varieties, yet had least greenhouse growth. Nutrient use with `Barbara Mitchell' was linearly correlated (R2>80%) to lab growth for seven of 12 ions. P and Fe supply was inadequate to support optimal growth, as indicated by low residual in media (>1% of MS formulation).
Differential Response of Cushaw Squash (Cucurbita argyrosperma Huber) Lines, Hybrids, and Landraces in Spring versus Fall Culture in Sonora, Mexico
Authors: Nunez-Grajeda Heli Cain , Garza-Ortega Sergio
Published: February 2019

Cushaw squash is cultivated in northwest Mexico mainly during the fall and to a lesser degree in the spring season, in which a lack of fruit production in experimental and commercial materials has been observed. This work was done to test 12 lines, 16 hybrids and six landraces regarding fruit and seed weight, flesh color, and soluble solids content (SSC) in both spring and fall seasons in year 2002. Estimates of fruit and seed yield were done. The crop was established by direct seeding at 0.5-m spacing between plants, on both sides of furrow-irrigated beds measuring 15 m long and 4 m wide. In the spring, fruit weight changed from 2.7 to 4.7 kg and seed weight from 17 to 118 g/fruit; fruit yield varied from 3.2 to 38.8 t·ha-1 and seed yield from 18 to 1131 kg·ha-1. Thirty-two percent of the genotypes, including lines and hybrids, but not landraces, were fruitless. SSC and flesh color had values from 4% to 7.5% and from 5.22 to 6.94 Y, respectively. For the fall culture all the genotypes showed good fruit set. Fruit weight in this season changed from 0.8 to 3 kg and seed weight from 22.3 to 97 g/fruit; fruit and seed yield varied from 4 to 28 t·ha-1 and from 135 to 923 kg·ha-1, respectively. All of the landraces were severely infected with squash leaf curl virus and had very low yields. SSC and flesh color, in this season, had values from 3.6% to 10.4% and from 5.1 to 7.94 Y, respectively.
Deployment of Molecular Markers and Marker-assisted Selection in Tomato Breeding
Authors: Foolad Majid R.
Published: February 2019

In tomato, Lycopersi conesculentum Mill., currently there are >285 known morphological, physiological and disease resistance markers, 36 isozymes, and >1000 RFLPs, which have been mapped onto the 12 tomato chromosomes. In addition, currently there are >162,000 ESTs, of which ∼3.2% have been mapped. Several tomato genetic maps have been developed, mainly based on interspecific crosses between the cultivated tomato and its related wild species. The markers and maps have been used to locate and tag genes or QTLs for disease resistance and other horticultural characteristics. Such information can be used for various purposes, including marker-assisted selection (MAS) and map-based cloning of desirable genes or QTLs. Many seed companies have adopted using MAS for manipulating genes for a few simple morphological characteristics and several vertical disease resistance traits in tomato. However, MAS is not yet a routine procedure in seed companies for manipulating QTLs although it has been tried for a few complex disease resistance and fruit quality characteristics. In comparison, the use of MAS is less common in public tomato breeding programs, although attempts have been made to transfer QTLs for resistances to a few complex diseases. The potential benefits of marker deployment to plant breeding are undisputed, in particular for pyramiding disease resistance genes. It is expected that in the near future MAS will be routine in many breeding programs, taking advantage of high-resolution markers such as SNPs. For quantitative traits, QTLs must be sought for components of genetic variation before they are applicable to marker-assisted breeding. However, MAS will not be a “silver bullet” solution to every breeding problem or for every crop species.
Genotype Analysis of Fruit Color using a Molecular Marker in Watermelon [Citrul luslanatus (Thunb.) Matsum & Nakai]
Authors: Bang Haejeen , Kim Sunggil , Leskovar Daniel I. , King Stephen
Published: February 2019

Fruit color and carotenoid composition are important traits in watermelon. Watermelon fruit color inheritance has revealed that several genes are involved in color determination. Carotenoids are known to have various functions in plants and animals, such as providing antioxidant activity and other health benefits for humans, and UV protection and pigmentation for plants. Differential gene activity in the carotenoid biosynthetic pathway may result in different color determination of mature fruit. Eight genes encoding enzymes involved in the pathway were isolated and their structures were characterized. While obtaining full-length cDNA of these enzymes, two single-nucleotide polymorphisms were detected in a coding region of lycopene β-cyclase (LCYB). These SNP markers showed cosegregation with red and canary yellow fruit color based on the genotyping of two segregating populations. This will lead to development of a codominant molecular marker for the selection of LCYB allele, which may allow breeders to distinguish between red and canary yellow watermelon fruit colors at the seedling stage.
Salinity Tolerance of Cleopatra Mandarin and Carrizo Citrange Rootstock Seedlings Is Affected by Higher Growth and Lower Water Use under CO2 Enrichment
Authors: Syvertsen Jim , Garcia-Sanchez Francisco
Published: February 2019

Two-month-old citrus rootstock seedlings of Cleopatra mandarin (CM) and Carrizo citrange (CC) were fertilized with nutrient solution, with or without additional 50 mM NaCl, and grown under either ambient CO2 (aCO2, 360 ppm) or elevated CO2 (eCO2, 720 ppm) for 8 weeks. Elevated CO2 increased plant growth, shoot: root ratio, net assimilation of CO2, leaf chlorophyll, and water use efficiency (WUE), but decreased plant water use. Salinity decreased growth, shoot: root ratio, net gas exchange and water use. Neither salinity nor eCO2 affected leaf chlorophyll fluorescence (Fv/Fm), but CC had higher Fv/Fm, leaf gas exchange, chlorophyll, N and Ca than CM. Although salinity increased leaf Cl and Na in both genotypes, CC had higher leaf Cl, but lower Na than CM. Salinity-induced decreases in leaf osmotic potential increased leaf turgor, especially at eCO2. There were no interacting effects of eCO2 and salinity on plant growth, but salinity decreased WUE more at eCO2 than at aCO2 in CM; but not in CC. Elevated CO2 decreased leaf Cl and Na in CC, but tended to increase both ions in CM leaves. Patterns of Cl and Na responses in roots generally were in opposite direction to their respective responses in leaves. Thus, the modifications of citrus seedling responses to salinity by higher growth and lower water use at eCO2 were not only species dependent, but also involved whole plant allocations of Na and Cl.
Coriander (Coriandrum sativum) Seed Yield as Affected by Selected Growth Stimulators
Authors: Morales-Payan J. Pablo , Stall William M.
Published: February 2019

Experiments were conducted to quantify the effect of various rates of a triterpenic-rich extract from Siberian fir (Abiessibirica) (TTA), acetylthioproline (AP), a seaweed (Ascophyllum nodosum) extract (CSE), gibberellic acid 3 (GA), and a glycine-rich commercial mixture of amino acids and short-chain peptides (APC) on coriander (Coriandrum sativum) seed yield. Aqueous solutions of GA, TTA, CSE, APC, and AP were sprayed on the crop leaves at 21 and 35 days after crop emergence. GA did not increase coriander seed yield as compared to the control. At the rate of 300 mg·L-1, TTA increased seed yield by about 9%. The highest seed yield increase was found in plants treated with CSE (60 mg·L-1), AP (250 mg·L-1), and APC (1200 mg·L-1), in which seed yield increased by about 14%. These results indicate that APC, AP, TTA, and CSE, but not GA, may be useful in increasing coriander seed yield.