bluuebunny/crossref_metadata_2025 huggingface dataset:
412 Organic Mulch Improves Yield and Economic Returns From Chive Production
Authors: Palada Manuel C. , Crossman Stafford M.A. , Davis Allison M.
Published: February 2019

Chive (Allium schoenoprasum) is one of the most popular culinary herbs in the Virgin Islands, and local demand is always high throughout the year. However, local production is not sufficient to meet increasing demands. Chive production is constrained by insect pests, weeds, and high cost of irrigation water. A study was conducted to compare the influence of organic and synthetic mulches on yield and economic returns from chive production. The study also evaluated the effect of mulch on weeds and water use. Chives were planted in plots consisting of three rows 3.6 m long. Plants were spaced 20 cm within rows 41 cm apart. The plots were mulched with grass straw, wood chips, shredded paper, and white plastic. A control plot (no mulch) was also planted for comparison. Plots were arranged in randomized complete-block design with four replications. All plots were drip-irrigated and soil moisture tension maintaned at 30 kPa. Chives grown with grass straw mulch produced taller plants and higher number of tillers (slips) than all other mulch treatments. Total fresh yield of plots with grass straw mulch was superior to all other mulch treatments including the control. On the average, plots with grass straw mulch produced 1203 g/m2 of fresh chives. All mulches resulted in reduced weed population compared to the control (no mulch). Due to high rainfall during the growing season, differences in irrigation water use were not significant. Economic comparison indicated that the net return above mulch costs was 50% higher with grass straw than with other mulch treatments. To improve production and income, herb growers should consider using grass straw and realize other benefits, including weed control and improved soil fertility.
416 An Update on Taxonomic Name Changes in Some Tropical Ornamental Plants
Authors: Criley Richard A. , Staples George W.
Published: February 2019

A new name for an old plant is not necessarily welcome in the horticultural trades or in plant identification classes, but some name changes have been in existence long enough that textbooks and trade publications should have caught up with them. The objective of this poster is to call attention to some of these changes for horticultural plant identification courses. Traditional references such as Hortus Third (1976) and Exotica 8 (Graf, 1976) have been superseded by the second edition of The Plant Book (Mabberly, 1997) and The Index of Garden Plants (Griffiths, 1994), while some recent works (The Tropical Look, Riffle, 1998) have chosen to retain old names. The taxonomic research underlying a new book, Tropical Garden Flora (Staples and Herbst, in press), based on the second edition of In Gardens of Hawaii (Neal, 1965), has produced an abundance of name changes. This poster will illustrate and report genera and species name changes that have occurred for selected ornamentals in the Acanthaceae, Agavaceae, Araceae, Araliaceae, Arecaceae, Commelinaceae, and Moraceae families plus a few others.
427 Inheritance of the Albino Trait in Daylily
Authors: Wharton Keith , Ching Alejandro
Published: February 2019

The albino genetic characteristic is a lethal condition in the post-seedling stage in plants. Although, it is an undesirable genetic characteristic, it is however an interesting genetic condition that can be utilized as a good practical genetic exercise for plant genetic and breeding courses. In this study, four commercial hybrid varieties of Hemerocallis were crossed as followed: A) “Stella D'ora” (with light orange flower) × “Happy Return” (with yellow flower); B) “Dark-eyed Magic” (purple with pink/cream variegated flower) × “Stella D'ora” (yellow flower). The seeds from these crosses were harvested and germinated in a plastic flat containing metromix 500 soil medium and placed under greenhouse condition. The germination of the seeds from each of the crosses resulted in the expression of green and albino seedlings in the F2; showing the typical Mendelian segregation of a dihybrid cross. Green was found to be dominant to albino. All the albino seedlings withered and died 2 weeks after germination. All four commercial hybrid varieties are carrier of the albino recessive gene.
442 Evaluation of Fungicide Treatments for Disease Protection of Zantedeschia elliotiana `Flame' in Florida Calla Lily Production
Authors: Reiser Ramona A. , McGovern Robert J.
Published: February 2019

Zantedeschia elliotiana `Flame' is a yellow calla with unique rust-colored blush, which is prone to a fungal/bacterial disease complex. Keeping calla rhizomes healthy and free of weakening by the most common fungal organisms Fusarium and Rhizoctonia, which minimizes secondary invasion and toppling by Erwinia carotova soft rot, the most prevalent cause of calla loss in production. Rhizomes were treated by pre-plant bulb dip or post plant drench either with fungicide or bactericide alone or in combination. Pot loss totaled with plants showing a lack of vigor resulted in 8%, 12%, and 14% loss in the most effective three treatments, which were: 1) the common commercial pretreatment (Champ II, Dithane, and Agtrol) 2) control plants and 3) RootShield (Trichoderma harzianum T-22). Upper (leaf and stem) plant fresh weights corresponded having heaviest weights of 47.8, 53.4, and 51.1 g and lower (bulb and root) with 129.5, 135.8, and 127.7 g/plant. The three least-effective treatments were streptomycin sulfate, Kocide 101, and ammonium bicarbonate, which showed losses of 26%, 30%, and 36%. Fresh weights coincided at 30.5, 39.9, and 36.7 g/upper portion and 117.1, 116.5, and 113.1 g/lower portion, lightest of all treatments. The remaining four fungicides with streptomycin sulfate, in order of effectiveness at 16%, 16%, 18%, and 20% loss, were Consyst, Banrot, Medallion, and Heritage. When loss exceeded 20%, flower number/plant also declined. Because plant survival and vigor were not increased with trial chemicals, the common commercial pretreatment or no treatment at all is recommended. Continued research might reveal beneficial optimum rates for other chemicals.
453 Evaluation of a Phosphate-charged Soil Material as a Source of Phosphorus for Soilless Root Media
Authors: Oh Young-Mi , Nelson Paul V. , Hesterberg Dean L.
Published: February 2019

A soil material high in metal oxides collected from the Bw horizon of a Hemcross soil in the state of Oregon was charged with phosphate, added to a soilless root medium, and evaluated for its potential to supply phosphate at a low, stable concentration during 14 weeks of tomato cropping (three successive crops). Three rates of phosphate were charged on the soil material, 0, 2.2, and 6.5 m P/g soil material and the soil material was incorporated into a 3 peatmoss: 1 perlite (v:v) medium at 5 % (40 g) and 10 % (80 g) of the volume of a 13.6-cm pot (1.0 L of medium). Uncharged soil material incorporated into soilless root medium at 5% and 10% reduced soil solution phosphate to deficient levels for 2 and 7 weeks, respectively. Phosphate was adequately supplied for 7, 10, 12, and more than 14 weeks in the 2.2P-5%, 2.2P-10%, 6.5P-5%, and 6.5P-10% treatment, respectively, as determined by symptoms of P deficiency. Phosphate and K levels in soil solution were highest at the beginning of crop 1 and tended to decline thereafter. Incorporation of soil material into soilless root medium improved pH stability whether it was charged with phosphate or not. The loss of the phosphate-charged soil material was negligible, 0.3% for the 6.5P-5% treatment and 1.2% for the 6.5P-10% treatment. The minimum critical concentration of soil solution phosphate for tomato in a 3 peatmoss: 1 perlite (v:v) medium as determined by the pour-through extraction procedure was found to be 0.3 mg·L–1 or slightly less.
461 Multimedia Dissemination On and Off Campus of Two Landscape Horticulture Courses
Authors: Kjelgren Roger , Rupp Larry
Published: February 2019

We developed two courses, sustainable landscaping and landscape water conservation, to meet time-constrained students on campus and place-bound students off campus. Lecture material consisting of text, slides, drawings, and some video were assembled digitally using presentation software. Each course was broken into nine to10 units by topic matter, and each unit consisted of 50 to 100 individual “slides” containing visuals, text, and audio narration. The lecture material was then packaged for student consumption onto videotape and CD-ROM, and on the Web (without audio) and as hard copy. Students taking the course received a course reader of the lecture material in hard copy and CD format. Contact with the instructor was through e-mail and a threaded newsgroup on the Web. All testing was with take-home quizzes and an exam. These courses had 700 to 800 slides averaging 1 min of narration per slide, equaling 12 to 14 h of audio. Assembly time for 1 h of narration, or about 60 slides, was 20 to 30 h. These courses are taught live in a classroom, where the presentation time is doubled compared to audio narration, alternate years, and have been available every term on an arranged basis. Survey results of 40 students to date taking the course on an arranged basis, obtaining lecture material mainly through CD-ROM, showed that by a 6:1 margin, their learning experience was overall positive. However, by a 19:1 margin, students would have preferred to have taken the course with live classroom instruction. Developing digital courses such as these is only feasible if a faculty member has unequivocal and ample administrative and financial support, and is only cost-effective if there is sufficient student demand outside of conventional scheduling.
473 Effect of Panicle Pruning and Bioregulators on Fruit Size in `Kohala' Longan
Authors: Núñez-Elisea R. , Crane J.H. , Caldeira M.L.
Published: February 2019

Panicles of `Kohala' longan (Dimocarpus longan Lour.) trees often retain more than 250 fruit, which results in small fruit (<10 g) of reduced market value. During 1997 and 1998, we conducted experiments to increase fruit size in commercial groves. Trees flowered and fruited normally in 1997, but very scarcely and late in 1998. In 1997, treatments consisted of panicle pruning (clipping off half of the panicle) and/or removal of entire panicles (50% per tree) when young fruits were 5 or 10 mm in diameter. Control trees were left intact. The number of fruit per panicle varied greatly within trees. Panicles (pruned or intact) with <125 fruit generally developed fruit >15 g (32–33 mm equatorial diameter). Total soluble solid content of mature fruit generally decreased with increasing fruit size. Removing whole panicles did not increase average fruit size in remaining intact panicles, suggesting that panicles were fed primarily by leaves within the same branch. In 1998, treatments consisted of applications of GA3 and/or CPPU (a synthetic cytokinin) when fruits were 6 to 9 mm in diameter. Panicles were not pruned since they generally had <150 fruit. Control panicles were not sprayed. There was no consistent effect of treatments on average fruit weight, and no treatment significantly increased fruit size in relation to controls. These preliminary results indicate that other factors besides current fruit set, such as previous fruit load of a branch, branch position (exposure to sunlight and/or wind, and proximity to major limbs), and the amount/age of leaves, may influence the fruiting potential of individual branches.
478 Characteristics of Fruit Flesh Pithiness Symptoms in `Yumyeong' Peach [Prunus persica (L.) Batsch]
Authors: Cho Myong-Dong , Kim Yong-Koo , Park Hee-Seung
Published: February 2019

`Yumyeong' peach has the desirable characteristics of long shelf-life and specific non-melting nature with a long harvest period. However, some fruits harvested too late show fruit pithiness symptoms or internal breakdown. This study was conducted to analyze the differences between fruit flesh pithiness and internal breakdown symptoms and to find out the source of flesh pithiness in `Yumyeong' peach. The rate of flesh pithiness was higher in fruit harvested late in the season. Sugar and malic acid contents showed no differences between the normal and flesh pithiness fruits, but the acidity was significantly lower and was affected by low citric acid content in flesh pithiness fruit. In flesh pithiness fruits, calcium contents were low both in skin and flesh. Occurrence of flesh pithiness fruits was high in the years with low precipitation and high temperature for 2 months before harvest. In observations on morphological characteristics, the parts showing flesh pithiness consisted of smaller cells than the normal parts. Tonoplasts disintegrated and the number of dead cells was high in internal breakdown fruits, while the tonoplasts were intact, with contracted vacuoles, in flesh pithiness fruits. Tylosises were observed in vascular tissues around the flesh pithiness; therefore, it was assumed that those tylosises restrict flesh tissue development, resulting in flesh pithiness. Other varieties (`Fantasia', `Wolmi' and `Hakuto') also showed tylosis, and smaller cells were observed in the flesh tissue of these cultivars, indicating abnormal growth of the flesh part. These results suggest the possibility of the occurrence of pithiness-like symptoms in other peach varieties.
487 Strategies to Enhance Production of Annual Globe Artichoke
Authors: Rangarajan Anusuya , Ingall Betsy A.
Published: February 2019

Annual production of globe artichokes (Cynara scolymus L.) requires vernalization of the plants, either through cold treatment of transplants or from natural temperature conditions in the spring. Studies were conducted in upstate New York to determine if artificial vernalization treatments could be achieved by earlier planting dates. Initial trials evaluated two cultivars used for annual production in other parts of the country—'Imperial Star' and `Green Globe Improved'. Transplants were set in the field with or without a vernalizing cool treatment, to determine the extent of natural vernalization achieved under New York conditions. `Imperial Star' produced slightly higher marketable yields than `Green Globe Improved' in 2 years of trials. Vernalization treatment increased the number of plants producing buds and the marketable yields, when transplants were set after 15 May. Natural vernalization was achieved and cold treatment prior to transplanting did not improve yields of plants established in early May. At later planting dates, vernalizing transplants increased the number of plants producing apical buds (largest) by about 20%, yet, >57% of non-vernalized plants of each variety produced buds within the season. Average bud sizes did not vary with vernalization treatment. A similar number of days from transplanting to first bud harvest (69 to 75) was noted regardless of planting date and size of transplant.
509 Defoliation Affects Return Bloom, Fruit Set, and Fruit Quality of Three Apple Cultivars
Authors: Davis David E. , Barden John A. , Byers Ross E.
Published: February 2019

In 1997 and 1998, we determined the effects of defoliation on return bloom and fruit set following a light cropping year. In one study, `Braeburn' trees were hand-thinned to a crop density (CD) of 3 fruit/cm 2 trunk cross sectional area (TCSA) in late May 1997, and then either completely defoliated or half of the tree defoliated by hand on one of five dates between June and Sept. 1997. Compared to a nondefoliated control, both whole and half-tree defoliation on all dates reduced fruit count and yield efficiency (kilograms per square centimeter of TCSA) and affected fruit weight, starch, firmness, and soluble solids in 1997. In 1998, return bloom and fruit set were reduced by most 1997 defoliation treatments. Compared to other dates, defoliation on 3 July caused the greatest reduction in return bloom in both whole and half-defoliated trees. In another study, `Braeburn' trees were hand-thinned to a CD of 5 in late May 1998; complete defoliation by hand on 1, 15, or 29 July reduced return bloom and fruit set in 1999; the 1 July treatment resulted in zero return bloom. `Golden Delicious' and `York' trees were thinned to a CD of 3 in late May 1998 and were hand-defoliated on 21 July or 12 August by removing every other leaf or removing three of every four leaves over the entire tree. In 1999, return bloom and spur and lateral fruit set were reduced by all defoliation treatments. Fruit set was most reduced by the 12 Aug. treatment. Fruit set for `York' was lower than for `Golden Delicious' in all cases.
512 Comparison of Freezing Protectant Sprays Applied to Avocado Trees
Authors: McNeil Robert J. , Medders David O. , Guzman Ramiro
Published: February 2019

Six freezing protectant products were sprayed at label rates on 1-year-old `Hass' avocado trees. Control trees were sprayed with water. Treatments were applied three times at monthly intervals, 20 Dec., 20 Jan., and 20 Feb. The products tested were Copper Count-N, Champ, Frostguard, Frost Shield, Anti Stress 550, and Insulate. Two separate orchard areas were treated, one with additional freezing protection by a wind machine and the other with no wind machine. Freezing temperatures and subsequent leaf damage occurred on 4 Jan., which was 2 weeks after the first treatment. The wind machine protected area experienced 2 h at or below 30 °F, with a minimum temperature of 29 °F, while the area without a wind machine experienced 5.5 h at or below 30 °F with a minimum temperature of 27.9 °F. One hundred mature leaves per tree were rated as to any freezing damage, slight damage (1% to 33%), moderate damage (33% to 66%), or severe damage (66% to 100%). All six freezing protectant products consistently reduced the percentage of leaves with freezing damage below that of the water-treated control trees, except in one instance, for all four categories of leaf freezing damage evaluated in both orchard areas—that with and that without a wind machine. Damage was reduced by approximately half for some of the treatments as compared to control trees. Data for some or all freezing protectant products was statistically different (less) than the control in two freezing damage categories (slight and moderate) in the area without a wind machine, however, data was not statistically different between freezing protectant products.
514 Influence of Storage and Sanitizing Protocols on the Physiology of Fresh-cut Watermelon
Authors: Fonseca Jorge M. , Rushing James W. , Testin Robert F.
Published: February 2019

Fresh-cut watermelon cubes stored at selected temperatures within the range of 1.1 to 14.5 °C had decreasing quality shelf life corresponding with increasing temperature. At lower temperatures there was a random occurrence of chilling injury symptoms in some cubes that was associated with the section of watermelon from which the cubes were cut. Cubes removed from the top side of the intact watermelon fruit were more susceptible to chilling injury than cubes from other sectors of the fruit. Sanitizing cubes with chlorine (40 ul/l) or ozone (0.04 μL/L) solutions caused an initial reduction in microbial count, but, during storage, the effect diminished and became insignificant compared to controls. Overall quality was lower in cubes receiving aqueous sanitizing treatments, possibly due to mechanical injury occurring during centrifugation to remove excess solution. Overall quality of cubes exposed to UV light (≈250 nm for 1 to 5 min) was better than cubes receiving aqueous sanitizing treatment. The effectiveness of UV treatment in reducing microbial load was dependent on the amount of cube surface exposed to the light. The results emphasize the importance of preventing microbial contamination during processing of fresh-cut watermelon.
519 Apoplastic Levels of Pectins and Free Galactose in Ripening and Chill-injured Tomato Fruit
Authors: Almeida Domingos P. F. , Huber Donald J.
Published: February 2019

Pectin solubility in ripening tomato fruit is typically studied in vitro, employing isolated cell walls; however, it is unknown whether in vitro studies address the actual changes in the status of pectins in the fruit in situ. In vivo pectin solubilization was examined in a pressure-extracted apoplastic fluid obtained from ripening and chill-injured tomato fruit with down-regulated polygalacturonase (PG) activity and untransformed wild-type. Pectin levels in apoplastic fluid increased 3-fold during ripening and were not affected by PG levels. In contrast, PG strongly affected pectin levels in bulk, enzymically active pericarp fluid. There was a 14-fold increase in bulk pectin levels during ripening of PG-antisense fruit and a 36-fold increase in wild-type fruit. Pectin levels in the apoplastic fluid of fruit stored at 5 °C for 14 days were 40% lower than that of freshly harvested mature-green fruit, but increased significantly upon transfer of fruit to 15 °C. Monomeric galactose in the apoplastic fluid increased from 41 mg·mL–1 at the mature-green stage to 67 mg·mL–1 in ripe fruit. Bulk levels of galactose were 3- to 4-fold higher than apoplastic levels. After low-temperature storage galactose levels were 50% and 20% lower than in freshly harvested fruit for the bulk and apoplastic fluids, respectively. These results indicate that in vivo pectin solubilization is restricted and largely independent of PG. Low-temperature storage reduces in vivo pectin solubilization, an effect that is reversed upon transfer of fruit to higher temperature following cold storage.
534 Use of Infrared Thermal Imagery for Ground-based and Real-time Detection of Water Deficit in Fruit Trees
Authors: Giuliani Rita , Flore James A.
Published: February 2019

Ground-based infrared thermal imagery was applied for early detection of plant water deficit, i.e., before photosynthetic activity is depressed and before growth processes are negatively affected by water shortage. Remote and real-time sensing of radiative canopy surface temperature was performed in Michigan in Summer 1999 on peach and apple orchards, using a digital IR imaging radiometer. Still images and videos were acquired on single canopies of well-watered plants and plants subjected to water depletion. Atmospheric parameters were monitored simultaneously. On apple trees, the apparent canopy temperature showed a wider thermal dispersion [10 °C], compared to peach tree canopies [2–5 °C]. Central tendency and shape parameters describing the canopy thermal distribution could identify, even for apple canopies, the thermal signal [1–2 °C] of plant water deficit, before changes in leaf net photosynthetic rate and fruit diameter were observed. The results of this study support the application of digital infrared thermal imagery and image processing for early recognition of plant water deficit. The decrease of the cost of available thermographic cameras makes their use feasible.
535 Oxygen Radical Absorbance Capacity (ORAC), Phenolic, and Anthocyanin Concentrations in Fruit and Leaf Tissue of Highbush Blueberry
Authors: Ehlenfeldt Mark , Prior Ronald L.
Published: February 2019

Antioxidant capacity as measured by ORAC, total phenolic, and total anthocyanin concentrations were evaluated in leaf tissue of the same 86 highbush blueberry cultivars, and ORAC and phenolic levels evaluated in leaf tissue of the same materials. Average values for ORAC, phenolics, and anthocyanins in fruit were 15.9 ORAC units (1 unit = 1 μmol Trolox Equivalent), 1.79 mg/g (gallic acid equivalents), and 0.95 mg/g (cyanidin-3-glucoside equivalents), respectively. `Rubel' had the highest ORAC values, at 31.1 units. Values for ORAC and phenolics in leaf tissue were significantly higher than fruit tissue, with mean values of 490.4 ORAC units and 44.8 mg/g in leaf tissue, respectively. No significant correlations were found between fruit ORAC and leaf ORAC, or between fruit ORAC and leaf phenolics. Investigation of ORAC values in a family of 44 `Rubel' × `Duke' seedlings showed negative epistatis for ORAC values. However, an analysis of ORAC values vs. pedigree in plants from the 86 cultivar groups suggested that, across cultivars, ORAC inheritance in generally additive.
542 Sulfur Source, Rate, and Method of Application for Polyethylene-mulched Tomato
Authors: Susila Anas D. , Locascio Sal J.
Published: February 2019

Tomato (Lycopersicon esculentum L.) was grown with polyethylene mulch and drip irrigation on a Millhopper fine sandy soil testing very high in P and low in organic matter during two season to evaluate the effect of S source, rate, and application methods on plant growth and yield of fruit. S rates of 34 and 68 kg S/ha were applied preplant (broadcast in the bed), by drip (10 weekly drip application), and by split applications (40% preplant and 60% drip). In split applications, S sources evaluated were ammonium sulfate and ammonium thiosulfate. Plant height was increased with S application from 0 to 68 kg S/ha in both studies. However, response on plant dry weight only occurred in Spring 1999. Total marketable yield was 17.9 tons/ha with 0 kg S/ha and was increased quadraticaly to 48.1 tons/ha with application of 68 kg S/ha in Spring 1999, but no response to S was obtained in the Spring 1998 study. Measured variable were not affected by S source and methods of application. Increasing S application from 0 to 68 kg S/ha reduced leaf and plant tissue P concentration 14% and 12% at mid season and 26% and 25% at late-season sampling, respectively. Application of 68 kg S/ha reduced soil pH ≈0.3 unit at the end of the season in both studies.
554 Mapping of QTL for Seed Size and Shape Traits in Common Bean
Authors: Park Soon O. , Coyne Dermot P. , Jung Geunhwa , Skroch Paul W. , Arnaud-Santana E. , Steadman James R.
Published: February 2019

Our objective was to identify QTL for seed weight (SW), length, and height segregating in a recombinant inbred line (RIL) population from the cross `PC-50' (Larger SW) × XAN-159 (Smaller SW). The parents and RILs were grown in two separate greenhouse experiments in Nebraska, and in field plots in the Dominican Republic and Wisconsin. Data analysis was done for individual environments separately and on the mean over all environments. A simple linear regression analysis of all data indicated that most QTL appeared to be detected in the mean environment. Composite interval mapping (CIM) analysis was then applied to the means over environments. Eight QTL for SW were detected on common bean linkage groups (LGs) 3, 4, 5, 6, 7, and 8. All eight markers associated with these QTL were significant in a multiple regression analysis (MRA), where the full model explained 63% of the variation among SW means. Six QTL for seed length were detected on LGs 2, 3, 4, 8, and 11 using CIM. The markers associated with the three seed length QTL on LGs 2, 8, and 11 were significant in a MRA with the full model explaining 48% of the variation among seed length means. Three QTL for seed height on LGs 4, 6, and 11 explained 36% of the phenotypic variation for trait means. Four of the six QTL for seed length and two of three QTL for seed height also appeared to correspond to QTL for SW.
556 In Vitro Anther Culture of Cucumber (Cucumis sativus L.)
Authors: Aboul-Nasr M.H. , Ahmed M.A.
Published: February 2019

This experiment was performed at the Tissue Culture Laboratory of the Horticulture Dept. of the Faculty of Agriculture at Assiut Univ., Egypt. After several attempts to determine the proper stage of buds for collection of pollen, we determined that the tetrad stage was most suitable. The pollen was cultured on either MS or B5 liquid or solid media (7% agar). Both media were used as basic salts or supplemented with growth regulators. The four growth substances were BA, NAA, K, and 2,4-D. Each growth substance was added to the medium separately as follow: BA, NAA at 15, 10, or 5 ppm; K at 0.1, 1, 2, or 5 ppm; and 2,4-D at 0.5, 1, or 5 ppm. The solidified medium was superior to the liquid medium at all the treatments that were used for callus formation. Using B5 medium did not result in any callus. The highest value of callus formation was obtained when MS medium supplemented with BA at 5 ppm. Moreover, the callus that was grown on the MS medium that had BA at 5 or 10 ppm developed a merstim tip. The control treatment produced calluses but did not develop any meristem tips. This process can be used to develop haploid plants.
567 Teaching Techniques and Course Modifications used to Enhance Horticulture Courses Utilizing Interactive Video Conferencing
Authors: McKenney C.B. , Auld D.L. , Cepica M.J. , Storey J.B.
Published: February 2019

Interactive video conferencing provides a useful medium for distance education. Due to the highly visual nature of many horticulture courses, the multimedia techniques utilized in video conferencing provide a rich platform from which to conduct many aspects of these efforts. Video conferencing also requires an overall evaluation of which common teaching techniques work and what possible modifications may be necessary to accomplish the desired teaching goals. Some of the topics for consideration in utilizing interactive video conferencing include encouraging participation of remote students, overcoming the feeling of viewing television, identifying the desired level of involvement by the students with the technology, considering alternative methods to reach desired course objectives, coordinating evaluation and testing, implementing classroom management techniques, and adding high touch to the high tech medium. Texas Tech and Texas A&M Universities have utilized interactive video conferencing at both the undergraduate and graduate levels. Some of the successful techniques as well as identification of a few of the pitfalls will be discussed.
576 Effects of NAA-800 and Retain on Fruit Retention and Quality of `Rome Beauty' and `Delicious' Apples
Authors: Fallahi Esmaeil , Greene Duane W.
Published: February 2019

Effects of various combinations of NAA-800 and Retain on fruit retention, yield, and harvest and post-storage fruit quality of `Rome Beauty' and `Delicious' apples were studied over one to three seasons. Retain and NAA-800 often reduced preharvest fruit drop as compared to control. Fruit from trees that received Retain at 123.6 g a.i./ha, or 61.8 g a.i./ha plus NAA-800 showed lower starch degradation pattern (SDP) at harvest and higher firmness. Retain treated fruit had lower evolved ethylene and respiration. Application of Retain at 61.8 g a.i./ha plus NAA-800 delayed fruit maturity, and the effects on fruit quality at harvest was comparable to the effects of this chemical at 123.6 g. a.i./ha. However, after storage, fruits from trees receiving Retain at 123.6 g a.i./ha often were firmer. Split applications of NAA-800 did not show major improvement in delaying fruit maturity over a single application. Application of NAA-800 at 585 mL/ha tended to reduce fruit firmness and increase fruit SDP. These fruits some times tended to have better color. Results on fruit color varied from year to year.
586 Cell Wall Protein Differences in Fruits of Two Tabasco Pepper Lines
Authors: Arancibia Ramon A. , Motsenbocker Carl E.
Published: February 2019

`McIlhenny Select' (easy detachment) and `Hard Pick' are two lines of tabasco pepper (Capsicum frutescens L.) that differ in the fruit detachment characteristics. Cellulase (Cx) and polygalacturonase (PG) activity, extracted from the fruit abscission zone, correlated inversely with the force needed to separate the fruit from the pedicel. A trend of higher Cx and PG is associated with the lower detachment force in the McIlhenny Select line. Differences in the fruit cell wall protein profile between both lines occurred during ripening. Two bands of 23 kDa and 40 kDa were higher in `McIlhenny Select'. A band of approximately 30 kDa was higher in `Hard Pick', while a band of ≈70 kDa increased in both lines. Isolation and characterization of these bands as well as Cx and PG is needed to understand the factors affecting fruit detachment in tabasco pepper.
594 Citrus Rootstocks Affect Scion Nutrition, Fruit Quality, Growth, Yield, and Economical Return
Authors: Zekri Mongi
Published: February 2019

Since the environmental conditions and cultural practices are unique in southwest Florida, a study was performed to determine the horticultural adaptability and performance of `Valencia' orange trees on four commercial rootstocks grown in a high-density planting. The trees were planted in 1991 on a flatwoods soil in a commercial grove at a density of 627 trees/ha. Leaf mineral concentration, growth, and fruit production and quality were measured 4 and 7 years after planting. Compared to Florida citrus leaf standards, leaf mineral concentration values were within the optimum to the high range. Yield efficiency expressed as kilograms of solids per cubed meter of canopy and juice quality in terms of juice content, soluble solids concentration, and kilograms of solids per box increased with tree age. Tree and fruit size were the highest for Volkamer lemon (Volk) and the lowest for Cleopatra mandarin (Cleo). Fruit yield was the highest for Volk. However, yield expressed in kilograms of solids per hectare was not significantly different between Volk and `Swingle' citrumelo (Swi) due to the higher solids per box for Swi. Yield efficiency was also higher for Swi than for Volk. Juice content and soluble solids in the fruit were higher for Swi and Cleo than for the lemon rootstocks. Financial analysis showed that at high-density planting, trees on Swi were the most profitable. On noncalcareous flatwoods soil, Swi is the best suited rootstock for high-density planting.
596 Location and Rootstock Effects on Sheepnosing in Grapefruit
Authors: Patil Bhimanagouda S.
Published: February 2019

Two-year field studies at three sites in the Lower Rio Grande Valley of Texas were conducted to evaluate the effects of location, rootstock, and irrigation on sheepnosing of `Rio Red' grapefruit (Citrus paradisi Macf.,) on sour orange (Citrus aurantium L.) rootstock. Based on the equatorial/polar diameter ratio, grapefruit grown in Weslaco had significantly higher percentage of sheepnosed fruits (62.66) than fruit grown in Mission (57.32), while Bayview had a negligible percentage of sheepnosed fruit (4.07). In a second study, `Rio Red' grapefruit grown on Carrizo [C. sinensis (L.) Osbeck × Poncirus trifoliate (L.) Raf.] had significantly higher percentage of sheepnosed fruit (59.46), compared to `Rio Red' grown on Swingle (C. paradisi × P. trifoliata) (47.83). In a third experiment, grapefruit with microjet irrigation had a significantly higher percentage of sheepnosed fruit (53.40), compared to flood irrigation (42.68). Although sheepnosed fruit had significantly greater peel thickness and a lower juice content, fruit quality was better because of higher soluble solids: titratable acidity ratio compared to normal shaped fruits. While significant, the irrigation and rootstock appear have a minor effect on sheepnosing less than growing location.
601 Development of Cultural Methods for Beach Plum (Prunus maritima Marsh.) Fruit Production
Authors: Uva Richard H. , Whitlow Thomas H. , Clark William F.
Published: February 2019

Beach plum is a shrub native to Atlantic coastal sand dunes from Maine to Maryland, where it is subject to drought and low nutrient and water holding soil. Since colonial times beach plum fruit has been collected from the wild for the production of preserves, an activity that endures today as a cultural tradition and cottage industry. Currently, the supply of fruit from wild stands does not meet the market's demand; hence, beach plum could be a new crop for many growers in the Northeastern U.S. For the past 4 years, a partnership of growers, Univ. of Massachusetts Extension, and Cornell Univ. has experimented with standard orchard cultural methods for beach plum production in coastal Massachusetts. During Aug. 1999, we harvested the first crop from our experimental orchard. The factorial experiment evaluates the effects of irrigation, mulch, and fertilizer on growth and yield of beach plum. Basal and axial growth were strongly correlated and were greater in fertilized than unfertilized treatments. Within fertilizer regime irrigation and mulch had less effect on growth than fertilizer. Fruit yield (dry weight and fresh weight) was greater in fertilized plots. Irrigation had no positive influence on yield. Average fruit diameter and °Brix were greater in the fertilized and unirrigated treatments.
607 Modulation of Heat Shock Proteins in Potato Leaves by Rhizospheric Calcium: Mitigation of Heat Stress Effect
Authors: Park Sookhee , Palta Jiwan P.
Published: February 2019

High temperature effects potato production by reducing overall growth and partitioning of photosynthate to tubers. Recent studies from our laboratory demonstrated that these effects can be reduced by increasing rhizospheric calcium. This present study was conducted to determine if this mitigation of heat stress effect on potato is due to modulation of heat shock protein by calcium during stress. An inert medium and nutrient delivery system capable of maintaining precise rhizospheric calcium levels were used. Biomass was measured and protein samples were collected from potato leaves. Using electroblotting, heat shock proteins were detected by antibodies to Hsp21 and Hsp70 (obtained from Dr. Elizabeth Vierling). Injury by prolonged heat stress was mitigated at calcium concentration >5 ppm. The calcium concentration of leaf and stem tissues were twice as high in 25 ppm calcium-treated plant compared to 1 ppm calcium-treated plants. Total foliage fresh weight was 33% higher and dry weight 20% higher in plants supplied with 25 ppm of calcium than supplied with 1 ppm of calcium. HSP21 was expressed only at high temperature and at greater concentrations in 25 ppm calcium treatment. HSP70 was expressed in both control, 20 °C/15 °C (day/night) and heat-stressed tissue, 35 °C/25 °C (day/night) under various calcium treatments (1 to 25 ppm). Also, there were some differences in HSPs expression patterns between young and mature leaves. Young tissue responded immediately to the heat stress and started to express HSP21 within 1 day. Mature tissue started to express HSP21 after 2 days. HSP21 of young tissue disappeared sooner than mature tissue when heat stress-treated plants were returned to normal conditions. These results support our earlier studies indicating that an increase in rhizospheric calcium mitigate heat stress effects on the potato plant. Furthermore these results suggest that this mitigation may be due to modulation of HSP21by rhizospheric calcium during heat stress.
609 Effects of CO2 Concentration and Photoperiod on Growth of Lettuce under High Humidity Conditions
Authors: Kitaya Yoshiaki , Moriya Tsutomu , Kiyota Makoto
Published: February 2019

Supplemental lighting and CO2 enrichment have been employed to promote plant growth in commercial plant production in greenhouses. In a semi-closed plant production system with a large number of plants at a high density, the relative humidity in the air around growing plants could be in excess of 80%. This research was initiated to determine the effects of CO2 concentration and photoperiod on the growth of plants under relatively high humidity conditions. In the experiment, lettuce plants were grown for 13 days under eight combinations of two CO2 levels (CO2, 0.38 and 0.76 mmol·mol-1), two photoperiods (PP, 16 and 24 h/day), and two relative humidity levels (RH, 80% and 90%) in growth chambers. The air temperature was 25 °C. Plants were illuminated with fluorescent lamps at a photosynthetic photon flux of 0.23 mmol·m-2·s-1. The dry mass of lettuce shoots (leaves and stems) grown in 0.76 mmol·mol-1 CO2, 24 h/day PP, and 80% to 90% RH was greatest in all treatments and was five times the least value obtained in 0.38 mmol·mol-1 CO2, 16 h/day PP and 90% RH. The dry mass of lettuce shoots decreased to 40% as RH increased from 80% to 90 % under 0.38-0.76 mmol·mol-1 CO2 and 16 h/day PP. Growth suppression by excess humidity was less significant in longer PP and higher CO2. Supplemental lighting and CO2 enrichment would be more effective for promoting growth of plants grown under higher humidity conditions.
625 Early Fall Defoliation of Southern Highbush Blueberry Inhibits Flower Bud Initiation and Retards Flower Bud Development
Authors: Williamson Jeffrey G. , Miller E.P.
Published: February 2019

In 1998, representative canes of mature, field-grown, `Misty' and `Sharpblue' southern highbush blueberry were hand-defoliated on 4 Sept., 2 Oct., 6 Nov., 7 Dec., or not defoliated. The experiment was repeated in 1999. Randomized complete-block designs with 11 (1998) or 10 (1999) replications were used. The early defoliation treatments (4 Sept. and 2 Oct.) resulted in reduced flower bud number per unit length of cane for `Misty', but not for `Sharpblue', when compared with later defoliation treatments or controls. A similar response to early defoliation was found both years for both cultivars. The later defoliation treatments (6 Nov. and 7 Dec.) had no significant effect on flower bud number compared to controls. Early defoliation had a negative effect on flower bud development for both cultivars. Flower buds that developed on canes defoliated on 4 Sept. or on 2 Oct. had smaller diameters than flower buds on canes defoliated on 6 Nov., 7 Dec., or on non-defoliated canes. Fruit fresh weight per unit cane length was less for the September and October defoliation treatments than for the December defoliation treatment or controls. These results support the need for summer pruning and a effective summer spray program to control leaf spot diseases that often result in early fall defoliation of southern highbush blueberries grown in the southeastern United States.
631 Photocontrol of Flowering and Stem Extension of the Intermediate-day Plant Echinacea purpurea Moench.
Authors: Runkle Erik S. , Heins Royal D. , Cameron Arthur C. , Carlson William H.
Published: February 2019

Intermediate-day plants (IDP) flower most rapidly and completely under intermediate photoperiods (e.g., 12 to 14 h of light), but few species have been identified and their flowering responses are not well understood. A variety of experiments was conducted to determine how light controls flowering and stem extension of Echinacea purpurea `Bravado' and `Magnus'. Both cultivars flowered most completely (79%) and rapidly and at the youngest physiological age under intermediate photoperiods of 13 to 15 h. Few (14%) plants flowered under 10- or 24-h photoperiods, indicating E. purpurea is a qualitative IDP. Plants were also induced to flower when 15-h dark periods were interrupted with as few as 7.5 min of low-intensity lighting (night interruption, NI). Flowering was progressively earlier as the NI increased to 1 h, but was delayed when the NI was extended to 4 h. Stem length increased by 230% as the photoperiod or NI duration increased, until plants received a saturating duration (at 14 h or 1 h, respectively). At macroscopic visible bud, transferring plants from long days to short days reduced stem extension by up to 30%. Flowering was inhibited when the entire photoperiod was deficient in blue or red light and was promoted in a far-red deficient environment, suggesting that phytochrome and cryptochrome control flowering of E. purpurea. Because of our results, we propose the flowering behavior of IDP such as E. purpurea is composed of two mechanisms: a dark-dependent response in which flowering is promoted by a short night, and a light-dependent response in which flowering is inhibited by a long day.
633 The Influence of Temperature, Irradiance, and Photoperiod on Crop Growth and Flowering of Angelonia angustifolia
Authors: Miller Amanda M. , Garner James M. , Armitage Allan M.
Published: February 2019

Five cultivars of the Angel Mist series of Angelonia angustifolia L. were evaluated in the Univ. of Georgia New Crop Program to determine the influence of temperature, irradiance, and photoperiod on crop growth and flowering. When the temperature was increased from 15 to 30 °C, days to visible bud and days to flower significantly decreased while height of flowers, vegetative height, and total height significantly increased. As irradiance increased, plant growth increased but little influence on flowering time was observed. Angelonia angustifolia appears to be a day-neutral plant with respect to flowering. The influence on growth regulators will also be discussed.
635 Sequential Testing to Determine Optimum Compost Maturity Levels
Authors: Klock-Moore Kimberly A. , Fitzpatrick George E.
Published: February 2019

Analytical determination and confirmation of minimum compost processing times and minimum curing times can aid commercial growers in selecting compost materials that should give them more reliable and consistent results in their operations. Five-cubic-yard volumes of yard-trimmings were assembled into three 1.25-cubic-yard compost piles at 60-day intervals. At the conclusion of the experiment, there were three piles each of compost of the following ages: 10 months, 8 months, 6 months, and 2 months. Compost was collected from each pile and screened through a 0.75-inch screen. Bulk density, water-holding capacity, air-filled porosity, carbon to nitrogen ratio, electrical conductivity, and ATPase activity were determined on samples from each reference compost pile. A bioassay using beans also was performed. These data will be presented.
638 Intercropping Buckwheat and Sweet Corn: Competition and Management Factors
Authors: Treadwell Danielle D. , Creamer Nancy G.
Published: February 2019

Row intercropping sweet corn (Zea mays L.) with a living mulch of buckwheat (Fagopyrum esculentum Moench) may reduce weed competition without reducing sweet corn yields. The objective of this experiment was to examine competition for nutrients, crop water use, and plant growth between weeds, buckwheat, and organically grown sweet corn, and examine the impact of buckwheat on weed densities and corn yields. In 1999, `Bodacious' (sehybrid) sweet corn was planted to 41,000 plants/ha stand and the following treatments were applied: 1) `Manor' buckwheat planted at 0 kg·ha–1, 56 kg·ha kg·ha–1, and 112 kg·ha–1, 2) buckwheat planted at three times: planting corn, at four-leaf corn and eight-leaf corn stage. A RCB design with four replications including a weedy/weed-free split was used. Above ground biomass of buckwheat was measured within a 1/2-m2 quadrat 8WAP and analyzed for C and N. Weed densities were taken within a 1/2-m2 quadrat 4WAP and 8WAP following each buckwheat planting. Buckwheat and corn tissue samples were analyzed for total nutrient content 8WAP. Soil samples were taken in corn and buckwheat interrows at emergence, 4 WAP, 8 WAP, and at harvest, and evaluated for inorganic nitrogen and soil moisture. Within rate treatments, yield was highest in weed and buckwheat-free (16.3 MT·ha–1) and lowest in weed-free 112 kg·ha–1 buckwheat (8.5 MT·ha–1). Within buckwheat timing treatments, yield was highest in 8 leaf (18.2 MT·ha–1) relative to at plant buckwheat. Weed densities were highest in no buckwheat (281 no/m2) and lowest in 56 kg·ha–1 buckwheat (28 no/m2) compared to the controls. These findings indicate buckwheat rate influences yield and weed density more than timing of buckwheat plant.