bluuebunny/crossref_metadata_2025 huggingface dataset:
Dry Matter Allocation and Loss in Jerusalem Artichoke (Helanthus tuberosus, L.) during Growth and Field Storage
Authors: McLaurin Wayne J. , Kays Stanley J.
Published: February 2019

Jerusalem artichokes are one of a small number of crops that store carbon predominately in the form of inulin, a straight chain fructosan. There has been a tremendous increase in interest in inulin due to its dietary health benefits for humans and calorie replacement potential in processed foods. We measured the allocation of dry matter within the crop (cv. Sunckoke) during an entire growth cycle by harvesting plants over a 40-week period (2-week intervals) from initial planting through field storage. Plant characters assessed were: no. of basal stems, leaves, branches, flowers, and tubers; the dry weight of leaves, branches, flowers, tubers, and fibrous roots; and date of flowering. Total dry weight of above-ground plant parts increased until 18 weeks after planting (22 Aug.) and then progressively decreased thereafter. Tuber dry weight began to increase rapidly ≈4 weeks (19 Sept.) after the peak in above-ground dry weight, suggesting that dry matter within the aerial portion of the plant was being recycled into the storage organs. Tuber dry weight continued to increase during the latter part of the growing season, even after the first frost. Final tuber yield was 13.6 MT of dry matter/ha.
Manual Onion Grading Equipment for Research and Commercial Applications in Developing Countries
Authors: Kline Wesley L. , Kline Shirley T.
Published: February 2019

Obtaining equipment for research in developing countries can be difficult, but it is possible to build some simple equipment with local materials. Onion varietal testing for the export market from Central America has been a major emphasis for the Honduran Agricultural Research Foundation. They have been carrying out evaluations since their inception in 1985, but did not have a good way to consistently grade large quantities of onions. To evaluate the yields, simple low-cost, and easily transportable grading equipment was constructed from materials readily available in the domestic market. Grading equipment must give uniform and repeatable results. Two grading systems were designed to provide that consistency. The first was the use of PVC (polyvinylchloride) tubing to construct 3and 4-inch grading rings. Yellow and sweet onions for export are divided into two classes—jumbo (3-4 inches with 65% 3-1/2 or larger in diameter) and colossal (larger than 4 inches in diameter). Rings were constructed by cutting 1-inch cross-sections of tubing and putting one inside the other until the desired diameter was reached. The rings were functional for small plots, but were not appropriate for large trials. A compact, collapsible grader, easily carried in the back of a small truck or van, was constructed for use on large trials. Local wood and steel bars were used for the section table and sizers. At the same time, growers were looking for a grading system that could be used in areas where there was no electricity. The grader was redesigned for commercial use, but was still portable. The designs for and cost effectiveness of the grading equipment will be discussed.
From Agronomy to Horticulture: The Diversification of Hawaii's Agriculture
Authors: Bevacqua Robert F.
Published: February 2019

Sugar cane and pineapple have dominated agriculture in Hawaii for more than 100 years. The plantation system that produced these agronomic crops is now in sharp decline, and a search is underway for horticultural crops, such as macadamia nut, papaya, and potted foliage plants, with which to diversify island agriculture. This paper, using the case study of potatoes and melons, describes the constraints encountered in establishing a 1000-acre farm enterprise on lands made available by the closing of Oahu Sugar Plantation in 1994. The major constraints were 1) a short-term lease with a clause for immediate revocation, 2) the reallocation of irrigation water from agricultural to conservation use, 3) the available plantation work force was ill-prepared for the varied tasks of horticultural production, 4) an irrigation infrastructure not compatible with vegetable production, 5) difficulty in expanding pesticide labels for local use, and 6) the absence of an institution to provide policy and technical assistance in addressing the above constraints.
Factors that Affect Teachers' Use of School Gardening in the Elementary School Curriculum
Authors: DeMarco Laurie W. , Relf P. Diane , McDaniel Alan
Published: February 2019

A national survey was conducted of teachers who use school gardening and horticulture as a teaching strategy to enhance student learning within a educational curriculum. The surveyed teachers are employed by schools that were recipients of a Youth Gardening Grant from the National Gardening Assn. in the 1994–95 and 1995–96 school years. The intent of this survey was to define the factors that are crucial to the successful implementation of school gardening into the elementary school curriculum as determined by educators who have already implemented such a program. The survey also described the characteristics of school gardening experiences at these elementary schools. Personal interviews with experienced school gardening educators in Virginia and Maryland verified survey results. Educators reported that the factors most responsible for school gardening success were a person responsible for school gardening activities, a growing site, and funding. Support of the principal and the availability of gardening equipment were also highly rated as success factors. Teachers indicated that, although these factors are important, they are not necessarily available at their individual schools. Responses also included an enormous listing of resources used by teachers to meet their school gardening needs. The survey overwhelmingly indicated that experienced educators view school gardening as a successful teaching strategy to enhance student learning. However, educators rely primarily on their personal knowledge of gardening to implement learning experiences with their students. Teachers feel that although their personal gardening knowledge is adequate, they are greatly interested in continued education in the use of school gardening and horticulture, either as in-service training, Master Gardener training, or for continuing education credit.
The Effects of the Green Brigade Program on Horticultural Knowledge, Attitudes, and Behavioral Changes of Juvenile Offenders
Authors: Dawson Carol , Zajicek J.M.
Published: February 2019

The Green Brigade, organized by the Bexar County Agricultural Extension Service in San Antonio, Texas, is a community-based horticultural program for juvenile offenders based on the earn while learning philosophy. This study determined if participation in the Green Brigade Program improved self-esteem, locus of control, interpersonal relationships, and attitudes toward school, toward gardening and toward the environment as well as decreased recidivism of juvenile offenders. To measure psychological variables, a pre-test, post-test design was implemented using the Self-Report of Personality from The Behavior Assessment System for Children (BASC). A questionnaire, developed by the researchers, measured environmental attitudes as well as basic horticultural knowledge. Youths participating in the Green Brigade were pre-tested on the first day of the session and post-tested on the final day of the 6-month session. Comparisons were made between children based on age, ethnic background, gender, and session of the Green Brigade in which they participated. Results determined the relationship between participation in the Green Brigade and the dependent variables mentioned previously.
Transplant Container Shape and Strawberry Transplant Growth
Authors: Bish Eric B. , Cantliffe Daniel J. , Chandler Craig K.
Published: February 2019

Bare-root strawberry transplants have been conventionally used for establishment of strawberry fruiting fields. These bare-root transplants have variability in vegetative vigor that results in irregular flowering patterns. We have been experimenting with a containerized transplant system to produce uniform transplants. Increasing transplant container volume by increasing perimeter, rather than depth, has resulted in increased plant size, but also increases transplant production costs. This study evaluated three container perimeters (17, 25, 32 cm) and three container shapes (circular, elliptical, and biconvex) such that different cell perimeters had the same greatest diameter. All containers had a depth of 3.5 cm. Root imaging analysis (MacRHIZOTM) was used to measure root growth in the container as well as root growth 3 and 6 weeks after transplanting. Increasing container perimeter led to increased plant growth before and after transplanting, but did not affect fruit production. Transplant container shape did not significantly alter plant growth or fruit production. Biconvex and elliptical containers required 25% and 15% less surface area, respectively. Therefore, a biconvex shaped container can be used to increase plant density during transplant propagation, decreasing surface area needed and reducing production costs.
ReTain™, A New Harvest Management Tool for Apple Production
Authors: Shafer Warren E. , Clarke Gregory , Fritts Robert , Woolard Derek
Published: February 2019

ReTain™ is an organic, water-soluble formulation that contains 15% (w/w) of aminoethoxy-vinylglycine (AVG). AVG, a naturally occurring plant growth regulator, competitively inhibits ACC (1-aminocyclopropane-1-carboxylic acid) synthase, the enzyme responsible for the conversion of S-adenosylmethionine (SAM) to ACC, the immediate precursor of ethylene in plants. ReTain has been under commercial development for the past 6 years, which includes U.S. EPA-approved Experimental Use Permit (EUP) programs in 1995 (Shafer et al., 1996, Proc 23rd Annu. PGRSA Mtg., p. 233–234) and 1996. Under the 1996 EUP, ReTain was tested on nearly 4000 acres of apples in 18 states. When used according to label directions (i.e., 50 g AVG/acre applied 4 weeks before anticipated harvest) with a nonionic surfactant, ReTain effectively reduced preharvest drop and generally resulted in fruit of higher quality than untreated (control) or naphthaleneacetic acid (NAA) -treated fruit. ReTain can delay fruit maturity (as indexed by starch conversion) by ≈7 to 10 days. ReTain-treated fruit were typically firmer (by 0.5 to 1.0 lb), produced significantly less ethylene, and maintained notably greater firmness through storage. The incidence and severity of watercore in `Delicious' was significantly reduced by ReTain, as was the frequency of fruit cracking in `Fuji' and `Gala' in several trials. Based on this benefit profile, ReTain can be an effective harvest management tool for apple growers. U.S. EPA approval for the commercial registration of ReTain is anticipated prior to the 1997 use season.
Physioecological Characteristics of Hanabusaya asiatica
Authors: Kim Won Bae , Choi Kwan Soon , Om Young Hyun , Lim Hak Tae
Published: February 2019

In an attempt to obtain the basic data for the development of Hanabusaya asiatica as horticultural plants, studies were conducted on the habitat environment, ecological characteristics, various treatments for breaking seed dormancy, and morphological and flowering characteristics of H. asiatica at different growth stages. Hanabusaya asiatica was distributed around areas of 850–1400 m above sea level with an inclination of 5–43°. The vegetation structure of H. asiatica was represented in groups as Quercus mongolica and H. asiatica. In a subgroup, Symplocos chinensis v. leucocarpa for. pilosa, Magnolia sieboldii, and Acer mono were included. Indication species of Quercus mongolica and H. asiatica were Quercus mongolica (B1 layer), Tilia amurensis (B2 layer), Rhododendron schlippenbachii (S layer), Ainsliaea acerifolia v. subapoda, Athyrium nipponicum, Spuriopimpinella brachycarpa, and Carex siderostica (K layer). Soil pH was about 5.4, and soil fertility was relatively in a good condition. The optimum conditions for seed germination was at 25Y.
Ornamental Landscape Potential of Several Ribes Species
Authors: Hummer Kim E.
Published: February 2019

Several species of Ribes have ornamental qualities worthy of consideration in residential and commercial temperate zone landscape plantings. Ribes sanguineum Pursh has been selected and cultivated throughout the Pacific Northwest, and boasts of early spring flowers of white, pink, or red. The two species of golden currants, R. aureum Pursh and R. odoratum Wendl. f., have brilliant yellow-fl owered racemes. Ribes species exhibit a broad diversity of plant habit and texture ranging from the upright 2.5 m, vigorous, and fully armed Menzieís Gooseberry, R. menziesii Pursh, to the prostrate shade-loving Crater Lake currant, R. erythrocarpum Coville & Leiberg. R. viburnifolium A. Gray remains evergreen in mild climates throughout the year. The foliage of some selections of R. americanum Miller and R. cynosbati L. brighten to a brilliant crimson red in the fall. The fall foliage of other species, such as R. hirsuta L., develop a continuum of color on their branches, from bright red at the apex, through orange and yellow to green towards the base. Spring bloom data and ratings of fall color for species in the Corvallis Repository collection will be described.
The Influence of Vegetation on UHIs, MUHIs, and Microclimate of Selected Southern Cities
Authors: Harp Derald A. , McWilliams Edward L.
Published: February 2019

Urban areas have average annual temperatures 2–3°C warmer than surrounding rural areas, with daily differences of 5–6°C common. A suggested reason for this temperature difference is the extensive use of concrete, asphalt, and other building materials in the urban environment. Vegetation can moderate these temperatures by intercepting incoming radiation. The influence of vegetation patterns on the magnitude of urban and micro-urban “heat islands” (UHI and MUHI, respectively) is compared for several cities including Houston, Austin, College Station, and Ft. Worth, Texas; Huntsville, Ala.; and Gainesville, Fla. Temperatures for all cities studied were greatest in the built-up areas and dropped off in suburban areas and adjacent rural areas. In Houston, surrounding rice fields were 3–5°C cooler than urban areas. Heavily built-up areas of Austin were 2–4°C warmer than parks and fields outside of the city. In all of the cities, large parks were typically 2–3°C cooler than adjacent built-up areas. Large shopping malls varied in nocturnal winter and summer temperature, with winter temperatures near door openings 2–3°C warmer, and summer daytime temperatures as much as 17°C cooler beneath trees. This effect seemed to persist at the microclimatic scale. Areas beneath evergreen trees and shrubs were warmer in the winter than surrounding grass covered areas. Video thermography indicated that the lower surfaces of limbs in deciduous trees were warmer than the upper surfaces. Overall, vegetation played a significant role, both at the local and microscale, in temperature moderation.
Growth Regulator Effects on Development of Three Bedding Plant Plugs
Authors: Wieland C.E. , Barrett J.E. , Bartuska C.A. , Clark D.G. , Nell T.A.
Published: February 2019

Salvia (Salvia splendens F.), vinca (Catharanthus roseus L.), and pansy (Viola × wittrockiana Gams.) were examined to determine efficacy of growth retardants for inhibiting stem elongation of seedlings in the plug stage and after transplanting to 10-cm pots. Studies on salvia showed plugs sprayed with single applications of ancymidol at 10 or 20 ppm, paclobutrazol at 30 or 60 ppm, or daminozide/chlormequat tank mix at 2500/1500 ppm inhibited plug elongation by 17% to 22%. Pansy plugs were sprayed either once or twice with ancymidol at 5, 10, or 15 ppm. Number of applications was statistically significant with two applications reducing elongation by an average of 35%, whereas a single application resulted in a 23% average reduction. Ancymidol concentration was significant in reducing stem elongation with increasing rates in pansy; however, the concentration and application time interaction was not significant. In both pansy and salvia, plant size at flowering was similar to controls after transplanting. Vinca plugs were sprayed with ancymidol at 5, 10, or 15 ppm either the 3rd week, 4th week, or both weeks after sowing. As ancymidol concentrations increased, plug height decreased, and the concentration effect was greater week 3 than at week 4. Two applications of ancymidol was most effective in retarding stem elongation (36%) followed by one spray the 3rd week (29%) and one spray during week 4 (20%).
Application of Growth Retardants in Subirrigation Water
Authors: Million J. , Barrett J. , Clark D. , Nell T.
Published: February 2019

Trials involving growth retardants applied in subirrigation water were conducted to evaluate the potential for this method of application and to determine critical concentrations for production of several floriculture crops. Eight concentrations of paclobutrazol or ancymidol ranging from 0 to 0.1 mg·liter–1 were applied continuously (from planting) to five crops. Based upon regression equations, paclobutrazol concentrations resulting in 20% size reduction were 0.005, 0.024, 0.017, >0.1, and >0.1 mg·liter–1 for begonia, chrysanthemum, impatiens, petunia, and salvia, respectively; for ancymidol, respective concentrations were 0.003, 0.01, 0.10, >0.1, and 0.058 mg·liter–1. A second set of trials compared the efficacy of a one-time vs. continuous application of paclobutrazol via subirrigation starting at 2 to 3 weeks after planting. For begonia, a one-time subirrigation application of 0.01 mg·liter–1 paclobutrazol resulted in 30% size reduction, while 0.003 mg·liter–1 applied continuously resulted in 20% size reduction. For impatiens, a one-time subirrigation application of 0.1 mg·liter–1 paclobutrazol resulted in 31% size reduction while 0.03 mg·liter–1 applied continuously resulted in 40% size reduction.
Chemical Regulation of Growth of Perennial Bedding Plants
Authors: Thomas Paul A. , Latimer Joyce G.
Published: February 2019

Perennial growers experience marketing difficulty when the stem length, or height of their perennial stock is excessive. Both wholesale and retail outlets desire to keep height to a minimum, while still promoting the production of flowers. The objective of this study was to screen containerized, spring-planted perennials for response to the growth retardants Sumagic, Bonzi, and B-Nine. Each perennial variety used was treated with B-Nine (Daminozide at 5000 ppm Bonzi (paclobutrazol) at 240 ppm, and Sumagic (uniconizole-P) at the following rates: 0, 40, 80, 120, and 160 ppm.Pre-cooled plugs of cultivars were selected from the genera Achillea, Coreopsis, Echinaceae, Digitalis, Gaillardia, Phlox, Rudbeckia, Alcea, Veronica, and Monarda. A randomized complete block design was implemented. Eight of the nine cultivars were responsive to Sumagic, with a 12% to 79% range of reduction in height. Seven cultivars were responsive to Bonzi with a 20% to 61% range of reduction. Only one cultivar was responsive to B-Nine, requiring two applications of 5000 ppm, to yield a 22% reduction in height at 4WAT. Based upon growers' desire for up to 50% height reduction, a 30% height reduction assessment point was established as a minimum rate for production, and a 50% to 60% reduction was established as the maximum landscape rate (based upon in-landscape persistence).
Expression of SolubleInvertase in Carrot (Daucus carota)
Authors: Yau Yuan-Yeu , Simon Philipp
Published: February 2019

The β-fructofuranosidases (invertases) cleave sucrose and related sugars into fructose and glucose. The enzyme is present in most plant tissues in multiple forms. Carrots contain an insoluble β-fructofuranosidase, which is ionically bound to the cell wall and soluble β-fructofuranosidases. The Rs locus in carrot conditions the accumulation of sucrose, fructose, and glucose. The inbred B493 is homozygous for the recessive allele (rs/rs) and accumulates high levels of sucrose, while most carrots accumulate glucose and fructose (Rs/Rs). Increased consumer interest in sweeter carrots require greater understanding of sucrose metabolism and its biochemistry. We established gene transformation systems for carrots using Agrobacterium-mediated and particle bombardment-mediated methods. Intact soluble invertase cDNA was synthesized from B493 and other carrots as measured by RT-PCR. The cDNA fragment was cloned into pBI121 and into a sequencing vector. B493 callus was transformed by Agrobacterium containing the pBI121 vector with invertase driven by the 35S promoter. Invertase expression was compared in rs/rs and Rs/Rs transformed carrots (with invertase overexpression) and non-transformed carrots. These results improve our understanding of the role of soluble invertase in sucrose metabolism of carrot.
Toward Characterization of and Breeder-friendly Molecular Markers for Genes Affecting Carotene accumulation in Carrot (Daucus carota)
Authors: Bradeen James M. , Simon Philipp
Published: February 2019

The Y2 locus conditions α- and β-carotene accumulation in the xylem (core) of carrot roots. The dominant allele suppresses carotene, but not xanthophyll accumulation, resulting in yellow-cored roots. Individuals homozygous for the recessive allele are rich in carotenes and are therefore orange-cored. Increased consumer interest in high carotene produce requires improved understanding of carotene biosynthesis and color development and more-efficient breeding techniques. We examined 103 F2 individuals generated from inbred populations differing in core carotene content. Bulked segregant analysis identified AFLP bands putatively linked to Y2. Linkage was confirmed for some bands by mapping. Linked bands were excised from gels, re-amplified, cloned into pGEM vectors, and sequenced. Cloned fragments and sequence information were used to characterize larger genomic regions to identify codominant markers. Currently we are developing codominant, PCR-based markers that can be used to rapidly genotype individuals in breeding programs, to characterize wild, feral, and cultivated populations for diversity and evolution studies, and to examine the role of Y2 in carotene accumulation.
Estimation of Genetic Variation in Grapes Based on RAPD and Isozyme Analysis
Authors: Lu J. , Liu Z. , Zheng Y.
Published: February 2019

Genetic relationships among 42 grape accession of at least 15 species were estimated and compared using RAPD and isozyme techniques. These accessions were either hybrids or wild collections of the Asiatic species, the American species, the European grape (V. vinifera), and muscadine grape (V. rotundifolia). A total of 196 RAPD fragments were generated from twenty 10-mer primers. The pairwise similarities among the accession ranged from 0.46 to 0.94. A dendrogram was generated based on the RAPD similarity coefficients. Species/accessions were basically grouped together in accordance with their geographic origins. The similarities and dendrogram resulted from the RAPD analysis were consistent with the ones generated from the isozyme data, and also consistent with the known taxonomic information. This result suggest that the RAPD method, like isozyme, is an useful tool for studying grape genetic relationship/diversity and origination.
Evaluation of RAPDs for Identification of Selfed Progeny in Cultivated Cranberry
Authors: Polashock James J. , Vorsa Nicholi
Published: February 2019

Most varieties of the American cranberry (Vaccinium macrocarpon) cultivated today were selected from native selections or breeding progeny between the late 1800s and mid-1900s. We have previously shown using RAPDs that contamination, i.e., a mixture of genotypes, is common in commercial bogs. One source of contamination could be establishment of selfed progeny. The purpose of this study was to determine how effective RAPDs would be in distinguishing selfed progeny from the parent. Results suggest that the number of scorable polymorphic bands is low compared to outcrossed or unrelated progeny. Thus, five to nine primers were used as compared to the three primers normally required to separate outcrossed and unrelated clones. Segregation of some RAPD bands was not consistent with expected mendelian ratios. However, using 9 to 12 polymorphic bands, only 3% to 5% of the selfed progeny had fingerprints identical to the parent. Additional primers should further reduce this percentage. It was also noted that certain cultivars exhibited a large number of non-parental bands. The origin of the non-parental bands has not yet been determined.
Seasonal Expression of a 700–800-Base Pair Transcript in Bark Tissues of Peach (Prunus persica)
Authors: Wisniewski Michael , Artlip Tim , Bassett Carole , Callahan Ann
Published: February 2019

Cold acclimation in temperate, woody plants involves distinct changes in gene activity and protein expression. We have been identifying proteins and genes that are associated with seasonal changes in cold hardiness. Seasonal changes in a 60-kDa dehydrin and its corresponding transcript have been identified, as well as seasonal changes in 16- and 19-kDa storage proteins. Further screening of a cDNA library, constructed from cold-acclimated bark tissues collected in December, identified a 700–800-bp clone that was seasonally expressed in Northern blots. The transcript began to accumulate in October, reached a peak in November–December, and then began to decline. By April, the transcript was no longer present in bark tissues. The transcript size indicates that this gene my be related to either the 16- or 19-kDa storage proteins previously identified; however, an amino acid sequence of the protein for comparison has not yet been obtained. Interestingly, the transcript is also expressed during the early stages of peach fruit development. A similar pattern between seasonal expression and fruit development has been observed for a peach dehydrin transcript. Analysis of a partial sequence of the clone has indicated a similarity to genes encoding proteinase inhibitors and thionins (a class of biocidal proteins). More definitive characterization of the gene and identification of its corresponding protein are in progress.
Determination of Nuclear DNA Content and Ploidy Level in Rubus by Flow Cytometry
Authors: Meng Rengong , Finn Chad E. , Doss Robert P.
Published: February 2019

Knowledge of the chromosome number in Rubus would be valuable when planning crosses and identifying plants, etc., however, preparation of tissue for microscopic evaluation and chromosome counting is difficult and time-consuming. Flow cytometry offers a more-efficient approach to this task. DNA flow cytometry was used to determine the nuclear DNA content in 22 Rubus genotypes. The genotypes represented a range of reported chromosome numbers from 2x to 12x. Six of the genotypes were representatives of Rubus ursinus, which is reported to have both 8x and 12x forms. Samples of nuclei were prepared from leaf discs of newly emerged and mature leaves following published protocols with some modifications. The DNA content was estimated by comparison of the fluorescence of Rubus nuclei with an internal DNA standard. There was an increase in nuclear DNA content concurrent with the increase in chromosome number. In these studies DNA flow cytometry could differentiate genotypes that differed by 2x, such as 6x and 8x, but could not reliably distinguish genotypes that differed by 1x, such as 7x vs. 8x or 6x. Aneuploids cannot be differentiated at this time.
Stylar Proteins Associated with Gametophytic Self-incompatibility in the Prunus
Authors: Tao R. , Yamane H. , Sassa H. , Mori H. , Murayama H. , Gradziel T.M. , Dandekar A.M. , Sugiura A.
Published: February 2019

Stylar proteins of four Prunus species, P. avium, P. dulcis, P. mume, and P. salicina, were surveyed by 2D-PAGE combined with immunoblot and N-terminal amino acid sequence analyses to identify S-proteins associated with gametophytic SI in the Prunus. All four S-allelic products tested for P. dulcis could be identified in the highly basic zone of the gel. These S-proteins had Mr of about 28–30 kDa and reacted with the anti-S4-serum prepared from Japanese pear (Pyrus serotina). Two of six S-allelic products tested for P. avium could be also identified in the 2D-PAGE profiles, with roughly the same pI and Mr as those of S-proteins of P. dulcis. Putative S-proteins for P. mume and P. salicina were found in the same area of 2D-PAGE as the area where S-proteins of P. avium and P. dulcis were located. N-terminal amino acid sequence analysis of these proteins revealed that they were similar to S-RNases reported previously.
Influence of Seedling Pretreatment and Explant Type on Watermelon Shoot Organogenesis
Authors: Compton Michael E.
Published: February 2019

Several methods have been published on shoot regeneration from watermelon cotyledon explants. The major differences in regeneration protocols include the light environment in which seeds are germinated and the cotyledon region used. The purpose of these experiments was to compare the two main protocols for plant regeneration and develop one general procedure. To fulfill this objective, seeds were germinated in vitro in darkness or 16-hr light photoperiod for 7 days. Cotyledon explants from four watermelon cultivars (`Crimson Sweet', `Minilee', `Sweet Gem', and `Yellow Doll') were prepared from both dark- and light-grown seedlings. Apical and basal halves were obtained by making a cut across the cotyledon width. Apical and basal quarters were made, for comparison, by cutting apical and basal halves longitudinally. All explants were incubated on shoot regeneration medium for 6 weeks followed by a 3-week cycle on shoot elonga-tion medium. The percentage of cotyledons with shoots was 1.7-fold greater for cotyledons derived from seedings incubated in darkness than those germinated in light. Shoot formation was about 10-fold greater for explants from cotyledon basal halves and quarters than apical halves and quarters. According to these results, the best watermelon regeneration protocol should consists of basal explants from in vitro-germinated seedlings incubated in the dark for 7 days.
Interaction of Culture Vessel Size, Medium Volume, and Carbon Dioxide Levels on the Growth of Various Plants in Vitro
Authors: Tisserat Brent , Silman Robert , Ray Karen
Published: February 2019

Ultra-high levels of CO2, i.e., >10,000 ppm, enhance tissue culture growth and offers a relatively simple and inexpensive method to improve plant productivity in vitro. Growth responses employing ultra-high CO2 levels differ considerably in the literature. Unfortunately, various culture vessels and systems have been employed, making comparisons difficult. In this study, the influence of the vessel container size, medium volume, and various CO2 concentrations (0 to 50,000 ppm) was studied on the growth obtained from lettuce and spearmint cultures. All three of these factors influence growth responses from plants cultured in vitro. Vessel types tested included: culture tubes, Magenta containers, 1-quart jars, 0.5-gallon jars, and 1-gallon jars having culture volumes of 55, 365, 925, 1850, and 3700 ml, respectively. Increasing the size of the culture vessel resulted in an increase growth regardless of the CO2 level tested. For example, fresh weight of spearmint increases of >250% can be obtained in by employing a 1-quart jar compared to using a culture tube. Increasing medium volume using various vessel types, especially using high concentrations of CO2, resulted in dramatic growth increases. For example, a >100% increase in fresh weight could be obtained by increasing the medium volume from 50 ml to 100 ml within a 1-quart jar. These studies suggest that plant growth promoted by supplemental CO2 is limited by the culture vessel size and medium volume. Differences in growth responses obtained in past CO2 studies could be related to vessel type and medium volume as well as the CO2 levels employed. Future in vitro studies should consider these factors in the evaluation of the influence of Ultra-high CO2 levels on plant growth. Peculiar growth responses, especially pertaining to rooting and shooting exhibited by cultures grown in ultra-high CO2 levels will also be discussed.
Photoautotrophic Micropropagation of Tomato Plantlets
Authors: Kubota C. , Abe N. , Kozai T. , Kasahara K. , Nemoto J.
Published: February 2019

`HanaQueen' tomato plantlets were cultured under conditions with different levels of sugar, photosynthetic photon flux, CO2 concentration, and number of air exchanges of the vessel. Effects of medium substrates (Gelrite or vermiculite) and explant preparation (with or without leaves) on growth of the plantlets were also examined. After 20 days in culture, photoautotrophically cultured plantlets with leafy explants, under increased PPF, CO2, and ventilation rate of the vessel had twice as much dry weight as those cultured conventionally with non-leafy explants under low PPF, CO2, and ventilation rate of the vessel. Dry weight of the plantlets was significantly greater when cultured with leafy than non-leafy explants. Net photosynthetic rate of the plantlets increased linearly as culture period when cultured without sugar, and remained almost zero when cultured with sugar, regardless of other culture conditions. Results obtained in this experiment have shown that tomato plantlets can be grown photoautotrophically, and the net photosynthetic rate was greater under photoautotrophic than under conventional photomixotrophic conditions.
Previous Cropping and Light History Influence Early Season Vegetative Development of Grapevines
Authors: McArtney Steven J. , Ferree David C.
Published: February 2019

Early season vegetative development of grapevines was studied in the year after imposing three cropping levels to mature `Seyval' vines in the field or establishing two light levels to potted `DeChaunac' vines growing in the greenhouse. Heavily cropped `Seyval' vines (averaging 90 buds, 15.8 kg fruit per vine over the previous two growing seasons) had 85% fewer count buds and 31% fewer non-count (latent) buds than lightly cropped vines (averaging 25 buds, 9.7 kg fruit per vine). The rate of leaf area expansion was reduced on heavily cropped vines. Covering `DeChaunac' vines in the greenhouse with 80% shade from bloom onwards reduced the leaf area per shoot in the year after treatment by reducing both the rate of leaf appearance and the rate of leaf expansion. The leaf at node four from the base of the shoot had the greatest area on both shaded and control vines; however, the area was reduced 33% on shaded vines. Data from the greenhouse experiment were used to model the effect of leaf size at the transition from sink to source on total source leaf area per shoot. Prior to bloom the total source leaf area per shoot was increased when individual leaves became sources earlier, i.e., at a lower percent of their final size. Whether a leaf became a source at either 30%, 50%, or 80% of its final size had little effect on total source leaf area per shoot after bloom. The proportion of source to sink leaf area at bloom was greater than 90% for both slow- and rapidly growing shoots (those on shaded and control vines, respectively). Expansion of grapevine leaves was reduced by heavy cropping and low light levels in the previous year, greatly reducing the source leaf area per shoot.
The Effects of Growth Regulators on Shoot Propagation and Rooting of Vitis Following in Vitro Axillary Bud and Shoot Apex Culture
Authors: Büyükdemirci Handan , Read Paul E.
Published: February 2019

Axillary buds of `Valiant' grapevine (Vitis spp.) grown in vitro were transferred onto Murashige and Skoog (MS) medium supplemented with different cytokinin and auxin combinations and concentrations. It was found that culture medium caused statistically important differences in number of nodes, number of fully expanded leaves, number of multiple shoots, number of roots, and length of shoots. MS medium supplemented with 1.0 mg BA/liter in combination with 0.01 mg NAA/L was found to be the best medium for shoot growth and callus production. MS medium supplemented with the combination of 0.5 mg BA/L and 0.01 mg NAA/L was the best medium for explant rooting. The medium containing BA and NAA encouraged better shoot growth than those containing BA alone. When the concentration of BA in the medium was increased, multiple shoot proliferation and teratological structures of explants increased, but the number of small leaves and length of internode decreased. Axillary bud culture led to better shoot growth than was found for shoot apex culture. The presence of leaves positively affected shoot growth from axillary buds. Also placing the axillary buds horizontally onto the medium gave better shoot proliferation and growth than placing them vertically.
Effect of Postharvest Temperature and Storage Duration on Growth and Flowering of the Phalaenopsis Orchid
Authors: Wang Yin-Tung
Published: February 2019

On 6 Sept. 1996, container-grown vegetatively propagated Phalaenopsis Atien Kaala `TSC22' plants were harvested and individually weighed. The bare-root plants were packed in cartons with shredded newspaper and placed in incubators at 15, 20, 25, or 30°C air temperature. Control plants were undisturbed. After 4, 7, or 14 days, one-third of the plants were removed from each temperature treatment, weighed, planted in pots, and then placed in a greenhouse. Mass loss (primarily water) increased with increasing air temperature and duration in storage. Symptoms of chilling injury (yellow blotches on leaves) were inversely related to 15 and 20°C storage temperatures. Chilling injury became more severe as storage duration increased. Plants had little or no chilling injury at 25 and 30°C, regardless of storage duration. Leaf loss was most severe on plants stored at 15°C for 7 or 14 days or at 30°C for 14 days. Increased storage duration up to 14 days did not affect the time of spiking (appearance of the flowering shoot) for plants stored between 15 and 25°C. Those kept at 30°C, regardless of the duration, spiked 5 to 8 days after the control. The results suggest that vegetative Phalaenopsis plants harvested in late summer should be stored and shipped at 25°C. Under such conditions, plants could lose 20% of the fresh mass between harvesting and planting without adversely affecting subsequent performance.
Uptake and Translocation of Fall- and Spring-applied Zinc in Bearing Apple Trees
Authors: Sanchez Enrique , Righetti Tim
Published: February 2019

A zinc timing study was carried out in `Jonagold'/EM26 trees using labeled zinc chloride (98.8 atom% Zn-68). In the fall, five spurs with strong flower buds on each of five trees were labeled with a micropipet with a solution of 1000 ppm Zn at the rate of 240 μg of Zn per leaf. Almost all the Zn-68 applied was recovered in the fallen leaves. Next spring, leaves and flowers clusters sampled from the treated spurs showed that only 3% of their total Zn was fertilizer-derived. A spring application was performed on five spurs and young terminal shoots of each of five trees. The developing leaves were labeled with 500 ppm Zn-68 solution at petal fall. Two weeks later, the entire spurs and the treated shoots were sampled. Zinc remained in the treated areas and it was not transported below or above the application zone. The study supports the contention that Zn is highly immobile in the tree and, if needed, it should be applied in early spring in order to promote rapid leaf and shoot growth. Fall applications of Zn-68 were absorbed but not transported from the treated leaves to the surrounding tissues. Therefore, Zn was not recycled for the next year's growth.
Emitter Placement and Calcium Plus Boron Solution Affect Elemental Content of Spur `Delicious' Apples
Authors: Funt Richard C. , Biggs M. Scott , Schmittgen Mark C.
Published: February 2019

Physiological disorders of apples, such as cork spot and bitter pit, are a result of low soil calcium, low or excessive soil moisture, large fruit size, and environmental conditions. We report on the effect of microirrigation treatments on apple fruit when irrigation is applied as water alone or water plus a calcium (Ca)/boron (B) solution with applications applied over the tree canopy or under the tree canopy. Apples were harvested from trees in their 4th to 7th leaf and the number of fruit and size of fruit varied from year to year. In most years, there were no significant differences among treatments for fruit Ca. Fruit B was significantly higher in treatments where B was applied through the irrigation. Fruit N/Ca levels were lower when the fruit size was smaller, which was due to a higher number of fruit per tree. Year to year variations in fruit Ca levels also were likely to temperature, humidity, rainfall, fruit size, and shoot growth.
The Methodological Study of Under-soil Heating System (USHS) for Warm-season Grass
Authors: Miwa Takashi , Kihara  , Tonogi
Published: February 2019

Recently, full-green turf on the sports fields in a winter period is highly required. The negative factor for warm-season grass pitch is its winter dormancy. Winter overseeding (WOS) is one of the successful methods to make them seem green. However, maintenance cost for winter overseeded turf is relatively expensive, and WOS itself involves some difficulties. On the other hand, under-soil heating (USHS) has been used only for cool-season grass pitch, but for warm-season grass pitch for the purpose to make them full green in a winter term. The objectives of this study are: 1) to confirm USHS's effectiveness for warm-season grass, 2) to make the specified system itself, and 3) to estimate the approximate heat demand. The results indicate that USHS can make warm-season grass green and maintain much higher turf quality, even in a severe winter period. The parameters needed to create the system are obtained. Those includes: heating pipe's spacing and depth, initial media temperature, and required soil temperature. In addition, USHS needs plastic cover for insulation, which light, air and water can pass through. Compared with WOS, this method can reduce maintenance fee and procedures such as preparation for WOS in a fall and transition in a spring. Thus, it can prolong total playing period. Moreover, it is easy to maintain the turf quality higher and maintenance cost can be less than WOS. The future subjects are to assess weed invasion, pests and diseases levels induced by USHS or by excess humidity, and to create a special maintenance program for this method.
Effect of Salinity on Blossom-end Rot of Tomato in the Closed Insulated Pallet System
Authors: Albahou M.S. , Green J.L.
Published: February 2019

Incidence of blossom-end rot (BER) of tomato is known to increase with increasing salinity in hydroponics and field tomato crops due to osmotic stress and imbalanced ionic ratio in the media solution. The present investigation evaluated salinity effects on the occurrence of BER of tomato in a completely closed root environment known as the closed insulated pallet system (CIPS). The CIPS is a continuous sub-irrigation capillary system with water moving from reservoir to rootzone in response to plant uptake and loss through transpiration and growth. In CIPS, fertilizer reserve is placed at the top surface of the root matrix, so fertilizer ions move downward by diffusion. Various tomato genotypes were seeded directly into CIPS in Spring. The experiment was terminated at a 100-day growing period. The incidence of BER was calculated as percent affected fruits. Salinity treatments consisted of five concentrations ranging from 0 to 10 g/L NaCl. One salinity treatment was 1 g/L CaCl2. In CIPS, the salt gradient created by uptake of saline water had lowest concentration at the top of root compartment where fertilizer was placed. Therefore, there was minimal ionic interactions between fertilizer ions and ions from the saline water. The uptake of water and plant growth decreased with increasing salinity concentration. The addition of Ca in the sub-irrigation water had no effect on the occurrence of BER. The incidence of BER correlated negatively with salinity level and plant growth in the CIPS.
The Effects of Different Ratios and Concentrations of Benzyladenin and GA4+7 on Fruit Size and Yield of Apple Trees
Authors: Clark Thomas E. , Robinson Terence L. , Lakso Alan N. , Stiles Warren C.
Published: February 2019

In 1996, benzyladenine, or GA4+7, or different ratios of BA: GA4+7 (100:1, 10:1 and 1:1) were applied to 10-year-old `Empire' apple trees on M.9 at 10-mm fruit size and 19-year-old `Redchief Delicious' apple trees on M.9 or M.9/MM.111 at 7.6-mm fruit size. Each chemical or combination of BA and GA was applied at three rates (50, 100, or 150 ppm) and at 75 ppm with 1.25 ml of carbaryl/L. At harvest, fruits were sampled from each treatment to determine fruit shape, firmness, color, total cell number, average cell size, and percentage of intercellular space. The positive rate response on fruit size and negative rate response on crop load of `Empire' became less significant for each formulation as the amount of GA4+7 in the formulation increased. The same was true for `Delicious', but less pronounced. At low rates of BA, formulations containing GA resulted in more thinning than BA alone. However, at higher rates of BA, formulations containing GA caused significantly less thinning than BA alone. For treatments combined with carbaryl, crop load increased linearly in `Empire' with increasing amounts of GA4+7 in the formulation. The treatment that provided the largest fruit size for `Empire' was BA@150 ppm, while for `Delicious' it was BA@75 ppm + carbaryl. Both varieties showed the greatest reduction in crop load with the 100:1@75 ppm+ carbaryl treatment when compared to the controls. These data suggest that GA4+7 in formulation with BA may inhibit the thinning action of BA at moderate and high rates.
Deficit Irrigation during Fruit Set Influences Fruit Number of Watermelons
Authors: Leskovar D.I. , Ward J.C. , Meiri A.
Published: February 2019

Reductions in the supply of high-quality irrigation water from underground aquifers is affecting production and irrigation management in the Winter Garden of southwestern Texas. This study was conducted to determine how growth, yield, and quality of watermelons [Citrullus lanatus (Thunb.) Matsum. & Nakai] grown with subsurface drip are affected by synchronizing irrigation with specific growth stages. In 1995 irrigation rates were: 1.0 evapotranspiration (ET) throughout the entire growth period (T1); 1.0ET until fruit set followed by 0.6ET until final harvest (T2); 1.0ET until fruit set followed by 0.6ET until first fruit maturity followed by 0.4ET until final harvest (T3); 1.0ET until fruit set followed by 0.6ET until first fruit maturity followed by 0.2ET until final harvest (T4). In 1996, two irrigation rates were constant 1.0ET (T1) and 0.5ET (T4), and two with varying ET rates throughout the entire growth period. Varying irrigation rates with specific growth stages had more influence on fruit set and early yield than on leaf and vine growth. Total marketable fruit yield ranged from 94.4 to 71.8 Mg·ha–1 when 569 mm (T1) and 371 mm (T4) of irrigation water, respectively, were applied in Spring 1995, and from 90.3 to 80.9 Mg·ha–1 when 881 mm (T1) and 577 mm (T4) of irrigation water, respectively, were applied in Spring 1996. However, plants irrigated with constant 0.5ET demonstrated greater water use efficiency than those with 1.0ET. Information on water use will assist farmers in designing management strategies that minimize risks due to uncertainties in weather and water supplies.