bluuebunny/crossref_metadata_2025 huggingface dataset:
016 NJUS STRAWBERRY BREEDING ADVANCED SELECTIONS FOR THE ANNUAL AND MATTED-ROW PRODUCTION SYSTEMS
Authors: Fiola Joseph A. , Jelenkovic Gojko , Galletta Gene
Published: February 2019

The major objective of the NJUS Strawberry Breeding Program is the development of early ripening cultivars with excellent fruit flavor and size for production under conventional matted-row, and high density annual production systems. In the 1993 replicated Step 3 trials (1991; 1992 planted), sixteen selections had higher yield than `Earliglow' (8127, 11312 kg/Ha), ranging from 8433 kg/Ha to 13334 kg/Ha. Thirty-one had higher weighted average fruit weight (WAFW) over the season than `Earliglow' (8.8 g; 8.4 g), ranging from 9.0 g to 12.3 g.

Selection for phenotype best suited for annual stem includes: low runnering, strong vigor, earliness, and large fruit size. In 1993 harvested Step III, four selections had comparable or higher yield (range: 12,866 to 27,128 kg/Ha) than `Chandler' (12,950 kg/Ha), as well as larger primary and WAFW (range: 13.5 to 16.4 g). All selections were significantly earlier than `Chandler'. In summary, the NJUS Strawberry Breeding Program has selections for the matted-row and annual production systems which are early, with excellent fruit flavor, size, and firmness for fresh market production.
018 EFFECTS OF ANCYMIDOL, PACLOBUTRAZOL, AND UNICONAZOLE ON GROWTH AND FLOWERING OF ACHIMENES cv HILDA UNDER TWO LIGHT LEVELS
Authors: Vlahos J. C.
Published: February 2019

Plants of Achimenes cv Hilda were treated with foliar sprays of Ancymidol, Paclobutrazol and Uniconazole at 3 different concentrations each, and were placed in a greenhouse at 21°C under 2 light levels (0 and 40% light exclusion) for 12 weeks. Reduced light level decreased plant height, number of axillary shoots and flowers. The three growth retardants in any concentration, supressed development of axillary shoots and flowers. Ancymidol at 25 and 50 mg.1-1, Uniconazole at 5 mg.1-1 and Paclobutrazol at 25, 50 or 100 mg.1-1 decreased plant height and number of leaf whorls. Number of rhizomes was reduced by the 3 chemicals at the highest concentration only. Paclobutrazol was most effective than the other 2 growth retardants. Effects of treatments were more pronounced under shade rather than in full sunlight. Days to anthesis was not affected by any of the treatments except by Paclobutrazol at 100 mg.1-1. The use of these growth retardants in concentration and mode of application similar to those used in this study is not recommended for “Hilda” as height retardation significantly reduces number of flowers
020 UNICONAZOLE TREATMENT IN PROPAGATION AFFECTS ELONGATION OF CHRYSANTHEMUM CUTTINGS
Authors: Schoellhorn Richard Kent , Barrett James E. , Nell Terril A.
Published: February 2019

Treatments were cultivar, uniconazole concentrations (0, 2, 4, or 8ppm), and time between dip and placement under mist (0, 10, or 60 minutes). Unrooted chrysanthemum cuttings of cultivars `Tara' and `Boaldi' were dipped in uniconazole solutions for 10 seconds. Data were taken 16 days after treatment. A quadratic relationship was found for the interaction between concentration and cultivar. `Tara': (y = 6.7277-1.532(x) + 0.119409(x2)) and `Boaldi': (y= 6.4676-0.884(x)+0.060020(x 2). Time had no significant interaction with either cultivar or uniconazole concentration.

In a second study, with uniconazole concentrations and storage time (10 minutes or 12 hours), main effects and the cultivar concentration interaction were significant.
023 USE OF GROWTH REGULATORS TO DELAY FOLIAR CHLOROSIS ON EXCISED EASTER LILY LEAVES
Authors: Han Susan S.
Published: February 2019

Yellowing of excised Easter lily leaves was significantly delayed by foliar application of gibberellic acids (GA3) ≥ 250 mg·1-1 or benzyladenine (BA) ≥ 50 mg·1-1. Rapid development of foliar chlorosis following cold storage was delayed significantly by applying 500 mg·1-1 of GA3 or BA before storage. Post-storage treatments were less effective. Development of chlorosis was associated with rapid loss of fresh weight and was not related to the aperture of the stomates. Respiration rate of leaves treated with growth regulators were significantly lower than that of the controls. Differences in the rate of carbohydrate depletion may explain the striking effects of growth regulators on the development of foliar chlorosis.
027 MULTIPLICATION OF ROSE SPECIES IN VITRO
Authors: Ma Yan , Byrne David H. , Chen Jing , Byrne Amanda
Published: February 2019

Several rose species (Rosa rugosa, R. wichuraiana, R. setigera, R. laevigata, R. banksiae, R. roxburghii, R. odorata and hybrids) were employed to establish the appropriate nutrient media for shoot multiplication and root initiation of cultured shoots and to describe a procedure for the successful transfer to soil of plants obtained in vitro. Cultured shoot tips and lateral buds from different genotypes proliferated multiple shoots on a basal medium (MS salt, vitamins, glycine, sucrose and agar) supplemented with 0mg/l to 6mg/l 6-benzylamino purine (BA) and 0mg/l to 0.5 mg/l naphthalene acetic acid (NAA). Most rose species cultured in a modified MS medium supplemented with 2mg/l BA showed good growth and shoot proliferation. The buds nearest the apex exhibited the slowest rate of bud development. Root development was enhanced and shoot development inhibited by lowering the concentration of MS salts to quarter- and half-strength. With difficult-to-root species, rooting was improved by supplementing the media with auxin or giving them 3-7days of dark treatment.
033 INHERITANCE OF THE BLOOD FLESH TRAIT IN PEACH AND INTERACTION WITH THE RED LEAF (GR) GENE
Authors: Creller Michael A. , Chaparro Jose X. , Werner Dennis J.
Published: February 2019

Inheritance of the blood flesh (red-violet mesocarp) trait in peach [Prunus persica (L.) Batsch] was investigated. `Harrow Blood' fruit began accumulation of anthocyanin about 40 days after anthesis. The blood-fleshed trait was associated with the red-veined leaf phenotype in `Harrow Blood' and its self progeny. An approximate segregation ratio of 3:1 (red vein:green vein) was observed in a population generated by selfing `Harrow Blood'. All 112 F1 progeny from a cross of `Harrow Blood' × `Rutgers Red Leaf'-2n produced wild-type fruit. Phenotypic segregation for red leaf:green leaf deviated from the expected 3:1 ratio in two of three F2 families derived from these F1's. More red leaf segregants were observed than expected. Bed-veined, green-leafed progeny comprised about 25% of the green-leafed seedlings in the F2. Examination of fruit on a limited number of F2 segregants revealed the presence of red-leafed, blood-fleshed individual. Preliminary results suggest that the blood trait may be controlled by two loci. The red-vein phenotype was associated with reduced tree height in self progeny of `Harrow Blood'.
036 INHERITANCE AND RAPID SCREENING FOR RESISTANCE TO EASTERN FILBERT BLIGHT
Authors: Coyne Clare J. , Mehlenbacher Shawn A.
Published: February 2019

U.S. hazelnut production, concentrated in Oregon, is threatened by eastern filbert blight and all currently grown cultivars are susceptible. Resistant cultivars offer the best control method. Field screening for resistance takes 2 years for symptom expression. The goal of this study was to develop a rapid and reliable screen; to confirm that resistance in `Gasaway' is conferred by a single dominant gene: and to investigate inheritance in seedlings of the resistant cultivar `Gem'. Nine controlled crosses made in 1987 and 1988 were screened in the greenhouse in 1992 and 1993. Three trees of each genotype were inoculated and scored for presence or absence of the fungus using either stained tissue sections or ELISA within 6 to 12 months. Progenies of `Vancouver Resistant' parents (resistant progeny of `Gasaway') segregated 1 resistant: 1 susceptible and from resistant × resistant parents segregated 3 resistant:1 susceptible in agreement with the single gene hypothesis. Seedlings of `Gem' were all susceptible.
037 EVALUATION OF XYLELLA FASTIDIOSA IN PRUNUS SPP.
Authors: Norton J.D , Abrahams B.R. , Boyhan G. E. , Huang Hongwen
Published: February 2019

Forty eight cultivars, species, and their progeny including Prunus americana P. angustifolia, P. cerasifera P. munsoniona, P. salicina, P. simoni, and P. triflora were evaluated for resistance to Xylella fastidiosa based on percent of scalded leaves and tree longevity. Observations indicate that resistance is heritable and controlled by recessive genes. Further, X. fastidiosa transmission was evaluated in plum and peach by chip and slip budding. Transmission as measured by enzyme-linked immunoabsorbant assay indicated that chip budding resulted in a higher level of transmission over slip budding in plum but not in peach. Neither Lovell nor Nemaguard rootstock had an effect on transmission.
038 COLLECTION OF WILD MALUS, VITIS, AND OTHER FRUIT SPECIES GENETIC RESOURCES IN KAZAKHSTAN AND NEIGHBORING REPUBLICS
Authors: Forsline Philip L. , Dickson E.E , Djangaliev A.D.
Published: February 2019

The USDA National Plant Germplasm System (NPGS) sponsored a 1993 collection of wild Malus in Kazakhstan and Kyrgyzstan which followed a collection in 1989 from sites in Tajikistan and Uzbekistan. There is strong evidence that the domestic apple originated in the foothills of the Tian Shari mountains where Malus sieversii (Ldb.) M. Roem remains as a primary forest species. The goal of the recent expedition was to obtain additional genetic diversity of apple from some of the remote sites in that area with the assistance of the Kazakh hosts. While there, isolated pockets of other fruit in the wild (especially Vitis) were discovered and collected. Seed collections from the expedition are stored with the NPGS and seedling populations are being evaluated for valuable traits.
042 EFFECTS OF VESSEL TYPE AND SUBCULTURE DURATION ON IN VITRO MULTIPLICATION OF PONTEDERIA CORDATA L.
Authors: Zurinsky Cynthia , Kane Michael E. , Philman Nancy
Published: February 2019

Studies were completed to optimize Stage II production efficiency of Pontederia cordata, a native wetland plant. Basal shoot tips from established cultures were subcultured into 60 ml glass culture tubes, 155 ml glass baby food jars, 350 ml GA7 polypropylene vessels or 500 ml clear polypropylene tissue culture containers containing full strength Linsmaier and Skoog mineral salts and organics supplemented with 3.0% sucrose, 2.0 mg/liter benzyladenine, 1.0 mg/liter indole-3-acetic acid, 50 mg/liter citric and ascorbic acids solidified with 8 g/liter TC® agar. Shoot tip to medium volume (ml) ratio was maintained 1:10 in each culture vessel. Vessel type had no significant effect on either shoot quality or multiplication rate (9.5 shoots/shoot tip/28 days). A maximum production efficiency of 1216 shoots/ft2/28 days was achieved using GA7 vessels. Stage II shoot multiplication rate significantly decreased when the interval between subculture exceeded 28 days.
043 IMPROVING THE MICROPROPAGATION OF PISTACIA VERA L.: EFFECTS OF AUXIN, TEMPERATURE, AND METHYL JASMONATE
Authors: Claveria Elisabet , Dolcet-Sanjuan Ramon
Published: February 2019

Micropropagation of Pistacia vera L. `Mateur' was improved with the addition of methyl jasmonate (MeJA) to the multiplication and rooting media. Shoot tip cultures established from grafted trees were maintained on a modified Murashige and Skoog medium containing 5μM BA and 0.05μM IBA. Addition of 1μM MeJA improved the multiplication rate but inhibited shoot growth when present at higher concentrations. Rooting experiments comparing the effects of IAA, NAA, or IBA at 0, 1, 3.2, 10, or 31.6 μM demonstrated a significant effect of temperature on auxin root induction for shoots maintained at 25 or 28°C. At 25°C NAA was better than IAA or IBA, whereas no differences among auxins were observed at 28°C. Addition of MeJA (0, 0.3, 1, 3.2, or 10 μM) to the best rooting media significantly improved the rooting percentage and root number. Greater than 80% rooting was obtained when 1 μM MeJA was added to both the root induction medium, containing 31.6 μM NAA, and the auxin-free medium. In addition, transfer to soil and acclimation was easier for plantlets rooted in MeJA-containing medium.
045 ANTIBIOTIC SUSCEPTIBILITY OF PLANT-ASSOCIATED BACTERIA
Authors: Buckley Patricia M. , Reed Barbara M.
Published: February 2019

Most bacteria isolated from persistently contaminated micropropagated mint plants were Gram-negative rods identified as xanthomonads, pseudomonads, and agrobacteria based on their cultural characteristics. A few Gram-positive, non-sporeforming bacteria were also found. Inhibition of bacterial growth by gentamicin and streptomycin was greater at pH 6.5 and pH 7.5 than at pH 5.5. Inhibition by rifampicin and Timentin was less affected by pH change. Pseudomonads were uniformly resistant to Timentin at all pH's and at levels up to 1000 μg/ml. Streptomycin at 500 μg/ml was bactericidal for the pseudomonads and Gram-positive bacteria while 1000 μg/ml was required to kill xanthomonads and agrobacteria. Minimal bactericidal concentrations for gentamicin varied widely, even within groups, and ranged from 10 μg/ml to >80 μg/ml for agrobacteria. These results emphasize a need to acquire basic information about the identities and antibiotic susceptibilities of microbial contaminants before attempting treatment of infected plant cultures.
047 CHROMOSOME ANALYSIS IN ALSTROEMERIA SPECIES AND CULTIVARS
Authors: Stephens Janice L. , Hughes Harrison G.
Published: February 2019

Alstroemeria is an important cut flower in the U.S. due to their wide variety of colors and to their long vase life. The most commonly grown cultivars were developed in Europe and their parentage has never been fully divulged. We are attempting to determine the probable parents of many of these cultivars through karyotype analysis and giemsa banding. Although preliminary karyotype analyses are available for 10 species and 25 cultivars, detailed karyotype analyses of only A. pelegrina and A. ligtu hybrids have been completed. Detailed karyotype analyses are now complete for 7 more species of Alstroemeria as well as the related genera Leontochir and Bomarea and 23 cultivars. A comparison among species and cultivars will be presented reflecting probable parentage of the cultivars. Results of giemsa banding will also be presented to further clarify cultivar parentage and relationships. This information should facilitate the more rapid development of successful cultivars by breeders in the U.S.
050 Complex Segregation Analysis (CSA) of Gerbera Flower Color
Authors: Tourjee Kenneth R. , Harding James , Byrne Thomas G.
Published: February 2019

The frequency distribution of gerbera flower hue in the Davis Population of Gerbera appears continuous and bimodal. This suggests that a gene of large effect may be segregating in a background of polygenic variation. CSA is a statistical technique developed in genetic epidemiology for investigating such complex traits, without the need of inbred lines. The REGC program of SAGE (Elston, LSU Med. Center, New Orleans) utilizes the regressive models of G. Bonney (1984) through pedigree analysis to provide estimates of major gene parameters and residual correlations among relatives. Pedigrees obtained from generations 14, 15, and 16 indicate that a major dominant gene for hue is segregating and accounting for ∼ 0.66 of the total variation. The genotypic means are 32 degrees and 71 degrees for the aa and bb genotypes, respectively. The `a' allele is dominant to the `b' allele and has a frequency of 0.55. The residual parent-offspring correlation estimate is 0.2, and measures the genetic contribution to the remainder of the variance.
051 GENETIC ANALYSIS OF POSTHARVEST LONGEVITY IN ANTIRRHINUM MAJUS L.
Authors: Stieve Susan M. , Stimart Dennis P.
Published: February 2019

Selecting for increased postharvest longevity through use of natural variation is being investigated in Antirrhinum majus (snapdragon) in order to decrease postharvest chemical treatments for cut flowers. The postharvest longevity of eighteen white commercial inbreds was evaluated. Twelve stems of each inbred were cut to 40 cm and placed in distilled water. Stems were discarded when 50% of spike florets wilted or browned. Postharvest longevity ranged from 3.0 (Inbred 1) to 16.3 (Inbred 18) days. Crossing Inbred 18 × Inbred 1 yields commercially used Hybrid 1 (6.6 days postharvest). The F2 population averaged 9.1 days postharvest (range 1 to 21 days). F3 plants indicate short life postharvest may be conferred by a recessive gene in this germplasm. Populations for generation means analysis as well as hybrids between short, medium and long-lived inbreds were generated and evaluated for postharvest longevity.
054 RESPONSE OF STRAWBERRY TO N FERTILIZATION BY DRIP IRRIGATION
Authors: Hochmuth George J. , Albregts Earl E. , Chandler Craig K.
Published: February 2019

During the 1992-93 fruiting season, strawberries were fertigated weekly with 0.28, 0.56, 0.84, 1.12, or 1.40 kg N/ha/day from ammonium nitrate. K was applied uniformly at 0.84 kg/ha/day by fertigation. Irrigation maintained soil moisture tension in the beds between -10 and -15 kPa. Fruit yields responded positively to N fertilization with yields maximized at 0.56 kg N/ha/day. Leaf N and petiole sap nitrate N concentrations increased with N rate with leaf-N for the plants receiving 0.28 kg N/ha/day remaining below 25 g·kg-1 most of the season. Sufficiency ranges for petiole sap nitrate-N quick testing were developed.
055 FRUITING RESPONSE OF STRAWBERRY IS AFFECTED BY K RATES
Authors: Albregts Earl E. , Hochmuth George J. , Chandler C. K.
Published: February 2019

During the 1992-93 fruiting season, straw berry plants were fertigated weekly with either 0.28, 0.56, 0.84, 1.12, or 1.40 kg/ha/day of K derived from KCl. Other nutrients were applied in the plant bed before fumigation except for N which was applied at 0.84 kg/ha/day by fertigation. Soil moisture in the plant beds was maintained between 10 and 15 cbs. Initial soil K tested medium with the Mehlich I soil test. Seasonal average fruit weight and percent marketable fruit decreased with increasing K rate. Seasonal fruit yields did not increase with K rates above 0.56 kg/ha/day. Leaf K concentrations increased with increasing K rates throughout the harvest season. The leaf K concentrations in the 0.28 K treatment were below 1% during the last month of harvest. K rates did not affect fruit firmness.
059 EFFECTS OF CALCIUM SPRAYS ON HIGHBUSH BLUEBERRY QUALITY
Authors: Hanson Eric J.
Published: February 2019

The effects of multiple calcium (Ca) sprays on berry quality of mature `Bluecrop' plants was tested for two seasons. In 1992, treatments supplied a total of 0, 1.0, 1.9 or 3.8 kg Ca/ha, in five applications between 18 June and 16 July. Calcium was applied as CaCl2. Concentrations for the highest rate ranged from 0.08% Ca in the first spray to 0.2% in the last. In 1993, treatments included a control, 12.1 kg Ca/ha applied as CaCl2, 24.2 kg Ca as CaCl2, and 12.1 kg Ca as the commercial product Nutrical (CSI Chem., Bondurant, IA). Seven sprays were applied between 4 June and 16 July, using concentrations of 0.1% to 0.4% Ca. Treatments had no effect on the percentage of soft or rotten berries, berry firmness, or Ca concentrations in berries in either year. Leaf Ca levels were increased slightly by higher application rates.
060 TEACHING INTRODUCTORY HORTICULTURE
Authors: Caldwell Judith D. , Reed David W.
Published: February 2019

Introductory horticulture courses are taught in almost every 4 year and 2 year horticulture program across the country, however, purpose, content and approach can vary widely among schools. Survey results will show how different schools use their introductory course (recruiting, foundation, service), class composition, topics most commonly included, textbooks used, standard teaching techniques and new or innovative techniques that have been especially effective.
061 LEARNING PREFERENCES IN HORTICULTURE
Authors: William Ray D.
Published: February 2019

Learning style preferences contribute to predictable actions by people. Basic researchers are fundamentally different than applied researchers in horticulture. Dilemmas associated with pesticides, worker protection, water, and labor issues often are related to differences in perception by relational versus linear thinkers. A participatory discussion will focus on these differences and how they can be combined to create dynamic and creative learning around complex issues facing horticulturists and consumers during the 1990's.
062 DECISION CASES TO ENHANCE LEARNING IN PRODUCTION HORTICULTURE COURSES
Authors: Hoover Emily , Foulk Doug , Davis David
Published: February 2019

Decision cases are designed to enhance students critical thinking by engaging them in authentic problem situations. Students are assigned the role as decision maker with a dilemma to solve. In the assignment, the decision maker has to weigh the issues, identify the options, and develop strategies for solutions either individually or as a group. The authors have been writing and using decision cases in upper level undergraduate production courses in fruits and vegetables to integrate information from classes in plant pathology, entomology, and production horticulture. Decision cases dealing with weed control strategies in small fruit production and vegetable production scheduling will be discussed to illustrate the strengths and weaknesses of the case approach.
063A WRITING TO LEARN IN THE PLANT SCIENCES
Authors: Joly Robert J.
Published: February 2019

Writing is a powerful tool for thinking and for clarifying complex subjects. It's a much more physical activity than reading. It compels students to organize their thoughts and present them clearly and logically. They must continually reassess whether what they've written is really what they want to say. The focus of this presentation is on the impediments to implementing this approach in our teaching. Our objective is to seek methods for reducing the work load of instructors while maintaining the quality of learning that can occur in a writing-intensive course. Results of workshops conducted during the 1993 North Central Regional Teaching Symposium entitled “Writing to Learn in Science” will be discussed. The workshops were active, participatory sessions designed to elicit as many responses as possible to the question “How can we utilize writing, intensively, in our courses?” Five obstacles or barriers to implementation of writing were identified. These include (1) instructor anxiety, (2) students requiring individualized instruction, (3) time-consuming evaluation of student writing, (4) in-class time needed for writing instruction, and (5) lack of student motivation. A focused-discussion format was utilized in these sessions, and groups of participants were given responsibility to devise creative actions or strategies that could be utilized to meet the challenges noted above. More than forty “actions” were identified which could help to make this approach feasible in both graduate and undergraduate. courses. These are summarized within five broad strategic approaches.
065 USING THE SERVICE COURSE CONCEPT IN HORTICULTURE
Authors: Lyons Robert E.
Published: February 2019

An undergraduate “Service Course” generally presents principles of a particular discipline in an uncomplicated manner needing no prerequisites. The target audience is typically students majoring outside the service course department or undeclared majors. The primary motives behind service courses are recruitment from within the university, providing non-mjors with a broad appreciation for a discipline, and providing graduate students with classroom teaching/management experience. `The structure, dynamics, success, and adaptability of “Indoor Plants,” a Virginia Tech Horticulture service course enrolling approximately 400 students per year, will be discussed. Comparisons with other service courses will be made.
068 EFFECT OF PRUNING SEVERITY ON APPLE TREE GROWTH, YIELD AND YIELD EFFICIENCY
Authors: Robinson Terence L.
Published: February 2019

`Empire'/M.26 apple trees which were planted in 1978 and trained to a Y-trellis were pruned differentially from 1989-1993. Trees were dormant pruned by removing from 1-4 scaffold limbs. The annual increase in trunk cross-sectional area (TCA), and the number and length of shoots removed during summer pruning increased linearly as the severity of pruning increased. The number of shoots removed during summer pruning from the most severe pruning treatment was more than double that of the least severe treatment Cumulative fruit number and yield were reduced linearly with increasing severity of pruning while average fruit size was increased only slightly by severity of pruning. Light interception was reduced with increasing severity of pruning. Tree efficiency of converting light energy into fruit (g fruit/MJ PAR intercepted) was linearly reduced with increasing pruning severity. Most of the reduction in conversion efficiency appeared to be due to reduced partitioning of resources into fruit since partitioning index (g fruit/unit increase in TCA) was more highly correlated to pruning severity than to conversion efficiency. Conversion efficiency and partitioning index accounted for a greater portion of the yield variation than did light interception indicating that the influence of pruning on yield was more a function of changing internal physiology than reduced light interception.
074 IMPLEMENTING EASTER LILY DEVELOPMENT MODELS IN A COMPUTER DECISION SUPPORT SYSTEM
Authors: Fisher Paul R. , Heins Royal D. , Ehler Niels , Karlsen Poul , Brogaard Michael , Lieth J. Heinrich
Published: February 2019

Commercial production of Easter lily (Lilium longiflorum Thunb.) requires precise temperature control to ensure that the crop flowers in time for Easter sales. The objective of this project was to develop and validate a greenhouse decision-support system (DSS) for producing Easter lily to predetermined height and flower date specifications. Existing developmental models were integrated with a knowledge-based system in a DSS to provide temperature recommendations optimized for Easter lily scheduling and height control. Climate data are automatically recorded in real time by linking the DSS to a greenhouse climate control computer. Set point recommendations from the DSS can be manually set or automatically implemented in real time. Potential benefits of the project include improved crop quality and the transfer, validation, and integration of research-based models. The DSS was implemented at several research and commercial locations during the 1994 Easter lily season. DSS recommendations were compared with the strategies of experienced growers. The system design, implementation, production results, quality of recommendations, and potential are discussed.
076 COMPONENTS OF A FLOWERING MODEL IN HELICONIA ANGUSTA
Authors: Kwon Funoh , Criley Richard A.
Published: February 2019

Bright red bracts with white flowers are produced by H. angusta from Sept through Dec in Hawaii. The inflorescences are valued as cut-flowers and the species is potentially adaptable as a seasonal potted plant. Sakai et al (1990) reported the LD responsiveness of this species, but-additional detail was necessary to permit scheduling. EK's PhD thesis developed a model for flowering in which the minimum day length requirement to initiate was 13 hr for 7 wk with another 15-16 wk required for development irrespective of the day length (12-18 hr) or temperature (14-22C). As with other phozoperiodically sensitive heliconias, 3 unfurled leaves were required to respond to LD. A growing degree model was developed to determine the time necessary to reach the 3-leaf stage. A 30-year temperature record was used to estimate the latest shoot emergence date that would permit initiation, development, and flowering under Honolulu conditions. The model was validated by comparison with commercial production records. Sakai et al. 1990. Bul Heliconia Soc Intl 4(4):10-11
079 ENVIRONMENTAL ANALYSIS: AN ALTERNATIVE AND ENHANCEMENT TO ANOVA
Authors: Hoyle Burton J.
Published: February 2019

Environmental analysis (EA) is described as a simplified system for determining significant differences between individual and groups of treatments within a test plot. It is based on recognizing and using the fact that each data point comes from a different environment in the soil. So called effects of blocks, rows and columns are ignored and replicates are ranked. Ranges of treatments are compared at corresponding levels of most to least favorable environment. The magnitude of a replicate is used only to indicate equal or better of one to another treatment. Significance levels are calculated or looked up in tables. EA is hundreds of times faster than ANOVA or regression analysis; results can often be obtained quickly by hand. Examples of EA are compared to ANOVA plus LSD and regression analysis. In all cases, results obtained by EA were nearly the same for the examples discussed. The predictive value of EA appears to be superior to the other methods. Techniques are shown for atypical ranking and other characteristics.
080 PREDICTING APPLE ROOTSTOCK PERFORMANCE FROM ENVIRONMENTAL VARIABLES
Authors: Olien W.C. , Ferree D.C. , Bishop B.L.
Published: February 2019

Rootstock recommendation is complicated by performance-site interactions. The N C140 Regional Project recently completed a lo-year evaluation of 9 rootstocks in locations across North America. Based on this data, we developed stability analysis models and demonstrated significant rootstock-site interactions for cumulative yield (CY) and trunk cross-sectional-area (CSA). The models require a site index (SI) estimated from mean performance over rootstocks within site. Prediction of rootstock performance in untested sites would be possible with an independent estimate of SI. We tested prediction of SI from mean maximum temperature (T) and total moisture received (M) and divided T and M into 5 phenological periods: Dee-Jan (Dormant), Feb-Apr (Prebloom), May-Jun (fruit Set), July-Sept (fruit Growth), and Oct-Nov (Postharvest). SICSA was not predicted by any T or M variable. SICY was predicted by TSet. TGrow, and MSet, but TSet and MSet were codependent. SICY was best predicted from a linear relationship with TSet.
082 OFFSETTING EFFECTS OF REDUCED ROOT HYDRAULIC CONDUCTIVITY AND OSMOTIC ADJUSTMENTIN DROUGHT-STRESSED PEACH, OLIVE, CITRUS, AND PISTACHIO
Authors: Rieger M.
Published: February 2019

Root hydraulic conductivity (Lp) and osmotic potential (π) were measured in young, drought-stressed and non-stressed peach (Prunus persica), Olive (Olea europea), Citrumelo (Citrus paradisi x Poncirus trifoliata) and Pistachio (Pistachia integerrima) plants. Drought stress reduced Lp 2.5 to 4.2-fold, depending on species, but π was reduced only in expanded citrumelo leaves and unexpanded olive leaves by 0.34 and 1.4 MPa, respectively. A simulation model of plant water uptake and leaf water relations was constructed to quantify the offsetting effects of reduced Lp and osmotic adjustment (OA) on turgor maintenance. For olive data, a 2.5-fold reduction of Lp caused a linear decrease in turgor pressure difference between stressed and non-stressed plants, such that the effect of OA was totally offset at a leaf water potential (stressed) of ≈ -3.0 MPa. For citrumelo, because the degree of OA was lower, the water potential at which the effects of OA and reduced Lp were offsetting with respect to turgor maintenance was ≈ -0.6 MPa. The analysis suggests that some level of stomatal closure would be necessary to extend the water potential range over which stressed plants maintain higher turgor than non-stressed plants for citrumelo. Conversely, no degree of stomatal closure would be required of stressed olive plants to maintain higher turgor than non-stressed counterparts over a physiologically meaningful range of leaf water potential.
084 WATER STRESS, PHOTOPERIOD, AND DIURNAL DISTRIBUTION OF SORBITOL CARBOHYDRATES IN APPLE
Authors: Wang Zhongchun , Quebedeaux Bruno
Published: February 2019

One-year-old `Gala' apple trees which experienced either water stress (WS) or no stress (CK) were exposed to a 60-min pulse of 14CO2. The distributions of newly-fixed 14C-photosynthates and total individual carbohydrates (both labelled and non-labelled) were monitored every 2 or 4 h for a 24-h period. During the 24-h period, half the WS and CK plants received 24-h continuous light and the other half received a 12-h photoperiod (8:00 am to 8:00 PM). WS stimulated the 14C partitioning into sucrose (suc) during the first 2-4 h period while the partitioning into glucose (glu) and fructose (fru) was inhibited in mature leaves. WS significantly inhibited the partitioning of 14C into starch. At the end of the 24-h period, a greater partitioning of 14C into sorbitol (sor) was observed under WS in leaves, stems and roots. WS lowered starch levels in all plant parts and the dark cycle further stimulated starch breakdown. Starch breakdown during the dark cycle resulted in the accumulation of glu and suc but not sor whereas in light sor accumulated with higher sorbitol/starch ratios. Light and energy requirements for sor synthesis and metabolism will be discussed.
094 CROPLOAD EFFECT ON BUD COLD HARDINESS OF Vitis labruscana L. cv. CONCORD
Authors: Wample Robert L. , Mills Lynn , Wichers Anna
Published: February 2019

An increase in mechanical pruning of Concord grapevines in Washington has led to a marked increase in yield. In 1993 the average yield for the 20,000 plus acres was slightly greater than 12 ton/acre. As part of a long term study, initiated in 1987, to evaluate the effects of mechanical pruning on Concord yield and fruit quality, we have also followed bud cold hardiness and winter injury over several years. Cold hardiness was monitored using low temperature exotherm analysis of excised buds. Winter injury was evaluated by visual examination of bud and cane tissues collected from vines with different croploads. In 1990 the average yield for mechanically pruned vines was 13T/ac and for balance pruned vines about 8T/ac. Winter injury during December 1990 showed significantly less injury to mechanically pruned vines whether primary, secondary or tertiary buds were examined. During the winter of 1991-92 and 1993-94 bud cold hardiness of individual vines showed no relationship to cropload per vine.
095 ROSETTING OF LISIANTHUS INFLUENCED BY CULTIVAR, SEEDLING AGE, PHOTOPERIOD, AND TEMPERATURE
Authors: Harbaugh Brent K.
Published: February 2019

Rosetting response was determined for four lisianthus [Eustoma grandiflorum (Raf.) Shinn.] cultivars exposed to photoperiod and temperature treatments during stage 1(14 to 43 days after sowing) and stage 2 (43 to 79 days after sowing) seedling development. Stage 1 seedlings were exposed to short days (12 h photoperiod) or long days (18 h photoperiod) in combination with high (26C) or low temperatures (12C). After stage 1 treatments, stage 2 seedlings were divided and exposed to the same treatment combinations resulting in 16 treatments. Seedlings were then grown at 22C for 120 days to determine rosetting response. Cultivars responded differently to temperature and photoperiod. Short day-high temperature exposure during either stage 1 or stage 2 resulted in the greatest number of rosetted plants (50 to 100%) for `Yodel White', `HeidiPink', and `BlueLisa'. `GCREC-Blue' did not rosette with short day-high temperature. Low temperature during stage 1 did not prevent rosetting when stage 2 seedlings were subsequently exposed to high temperature, but low temperature during stage 2 decreased rosetting of seedlings exposed to high temperature in stage 1. Less rosetting occurred with long day-high temperature than with short day-low temperature, especially for `Blue Lisa'.
097 EFFECT OF EXTENDED LIGHTING ON POINSETTIA `ECKESPOINT FREEDOM'
Authors: Wilfret G. J.
Published: February 2019

Poinsettia `Eckespoint Freedom' (Euphorbia pulcherrima), grown as single pinched plants in containers in a shade house (30% light exclusion) during 1992 and 1993, were provided interrupted night lighting from 2200 to 0200 hr. to determine the effect of extended lighting on vegetative and reproductive development. Plants were moved to short days at 2 day intervals from 14 Sept to 26 Oct 92 and from 26 Sept to 26 Oct 93 and were compared to plants grown with ambient daylengths. Dates of first bract in full color for ambient-day plants were 31 Oct 92 and 04 Nov 93. Marketable dates (5 bracts in color) for ambient-day plants were 21 Nov 92 and 18 Nov 93. Bract development was delayed in direct proportion to lighting beyond 02 Oct 92 and 04 Oct 93. Number of vegetative nodes increased from 7.4 to 12.8 and from 6.3 to 12.0 when ambient-day plants were compared to plants lit to 26 Oct of 1992 and 1993, respectively. Lateral stem caliper, measured 2 cm above the axil, was significantly greater on plants lit beyond 10 Oct. Plant stature was more upright when lit beyond 16 Oct, which was 30 days from pinching.
098 ACCELERATING GROWTH OF PLUG-GROWN PANSIES WITH CARBON DIOXIDE AND LIGHT
Authors: Kaczperski Mark P. , Armitage Allan M. , Lewis Pamela M.
Published: February 2019

Seed of Viola × wittrockiana `Majestic Giant Yellow' were germinated in #406 plug trays at ambient CO2, 25 C and a light intensity of 100 μmol s-1m-2 with an 18 hr photoperiod. At emergence and at successive one week intervals, seedlings were exposed to CO2 levels of 500, 1000 or 1500 μl l-1 and irradiances of 100, 225, 350 μmol s-1m-2 for 7 to 35 days, after which seedlings were transplanted into 10 cm pots and grown to flower in the greenhouse. CO2 at 1000 μl l-1 was as effective as 1500 μl l-1 in accelerating growth in the plug stage. 500 μl l-1 at all irradiances did not accelerate growth significantly. Plants grown at 1000 μl l-1 and 225 μmol s-1m-2 intensity reached the 5 leaf stage up to 14 days earlier than the control, as well as decreasing time to flower during the growing on phase.
099 LIGHT AND TEMPERATURE AFFECT SPIKING AND FLOWERING OF THE PHALAENOPSIS ORCHID
Authors: Wane Yin-Tune
Published: February 2019

To determine the impact of light on spiking during forcing, mature pot-grown Phalaenopsis Joseph Hampton `Diane' plants were exposed to 0, 8, 60, or 160 μmol·m-2·s-1 of PPF while being subjected to 20C day/15C night (12 hr each) air temperatures for six weeks. Flower spikes emerged in an average of 27 and 33 days for plants exposed to 160 and 60 μmol·m-2·s-1 PPF, respectively. Those exposed to 8 μmol*·m-2·s-1 of PPF or kept in darkness did not spike after six weeks. In a second experiment, plants were kept in complete darkness for 2, 4, or 6 weeks at 20C day/15C night before exposed to 160 μmol·m-2·s-1 of PPF for six weeks. The average days to spiking for those kept in darkness for 2, 4, and 6 weeks were 30, 31, and 35, respectively, after lighting began. Therefore, light exceeding a certain level is required during the induction of spiking. Regression analysis of the results from a third experiment shows that, at a common day temperature of 25C, anthesis was delayed by one day for each 1C decrease in night temperature between 25C and 15C. Night temperature had no effect on flower count or size.
109 SIDE-DRESS CALCIUM FERTILIZATION INFLUENCE ON POTATO YIELD AND QUALITY
Authors: Clough George H.
Published: February 2019

Potato (Solanum tuberosum) cv. `Russet Burbank' response to source of side-dress Ca fertilization applied at 0, 28 and 56 kg·ha-1 Ca on fine sandy loam soil was evaluated. Side-dress Ca source and rate did not affect number or total weight of tubers/hill, average tuber weight, or tuber macronutrient concentrations at mid-season. Tuber B concentration was significantly greater with the 12-0-0-10.5 source as compared to the check. Tuber Fe concentration decreased linearly as 22-0-0-7 rate increased from 0 to 56 kg·ha-1 Ca. No other micronutrient concentration was affected by the applied treatments. Calcium fertilization had no effect on tuber yield, grade distribution, or specific gravity. The predominant internal defect observed was brown center, which was reduced at harvest by side-dress Ca application. Internal quality and french fry color were evaluated after storage for 4 months.
110 WATERMELON PRODUCTION AS INFLUENCED BY LIME, GYPSUM. AND POTASSIUM RATE
Authors: Locascio S. J. , Hochmuth G. J.
Published: February 2019

Watermelons [Citrullus lanatus (Thunb.) Matsum. & Nakai] were grown with three rates each of lime, gypsum, and K during two seasons to evaluate their effects on fruit production and mineral concentration. The first experimental site was a recently cleared Sparr fine sand with an initial pH of 5.4 and Mehlich I extractable K of 32 ppm (low) and 948 ppm Ca. The second site was a virgin Pomona fine sand with a pH of 4.8, 28 ppm K, and 612 ppm Ca. `Crimson Sweet' fruit yield was reduced 10% with an increase in lime rate from to 4.48 Mt·ha-1 in the first season. In the second season, lime rate had no effect on yield. In both seasons, fruit yields were reduced 14% by an increase in Ca from gypsum from 0 to 1.12 Mt·ha-1. Fruit yields were not influenced by K rates from 90 to 224 kg·ha-1. Application of lime and gypsum increased leaf tissue Ca concentrations and decreased K. An increase in K application significantly increased leaf K and decreased Mg in the first season but not significantly in the second season. Fruit firmness and soluble solid content were not consistently affected by treatment.
114 CALIBRATING PLANT SAP QUICK TESTS FOR NO, AND K+ ON WINTER SNAP BEANS
Authors: Lamberts Mary , O'Hair Stephen K. , Hochmuth George , Hanlon Edward
Published: February 2019

Seventy-five percent (75%) of U.S. produced winter snap beans are grown on limestone soils in southern Dade County, Florida Since this crop requires 60-70 days from planting to harvest, growers need information to make changes in fertilizer practices on an almost instantaneous basis. As part of a study to calibrate soil tests with yield responses to different levels of applied fertilizers, plant sap quick tests are being calibrated with laboratory analyses of whole leaf samples. Beans were grown at two locations -- in a grower's field and at the University of Florida Tropical Research & Education Center (TREC). Samples were taken simultaneously for both plant sap quick tests using petioles and for whole leaf tissue analyses. Results and how these have been extended to local growers will be presented.
121 TREE GROWTH, LEAF NITROGEN, NET GAS EXCHANGE, AND CARBON ISOTOPE DISCRIMINATION IN CITRUS
Authors: Syvertsen Jim , Lloyd J. , Farquhar G. D.
Published: February 2019

Four to six-yr-old `Red Ruby' grapefruit trees on either `Volkamer' lemon (VL) or sour orange (SO) rootstocks were fertilized with 3 rates of nitrogen (N) over a 3 year period. We studied the effects of leaf N concentration on stomatal conductance (gs), net assimilation (A) of CO2 (Li-Cor portable gas exchange system), carbon isotope discrimination (δ 13C) of tree tissues, root growth, canopy development and fruit yield. Using springtime measurements of net gas exchange during the fifth year, gs, A and leaf tissue δ 13C were positively correlated with leaf N. The faster growing trees on VL had larger canopy volumes and fruit yields but lower leaf N, A and δ 13C than those on SO. Thus δ 13C was positively correlated with A but negatively related to tree size and yield. By the sixth year, δ 13C was still related to N but tree growth had apparently obscured any rootstock effects on leaf N, water use efficiency, A and δ 13C. Leaf and trunk bark tissue δ 13C did not differ but root bark had lowest δ 13C regardless of rootstock species.
123 MOVEMENT PROTECTS CARAMBOLA LEAFLETS FROM HIGH LIGHT AND TEMPERATURE STRESS
Authors: Marler Thomas E. , Lawton Patrick J.
Published: February 2019

Leaflets of carambola were restricted to a horizontal position for 3.5-h during late morning and early afternoon on sunny days to determine the influence of natural leaflet movement on temperature and chlorophyll fluorescence. Adaxial temperature of these horizontal leaflets was 5-9 C higher than that of leaflets that were allowed to move in response to high light. Chlorophyll fluorescence was similarly affected. Leaflets that were allowed to move had a higher Fv/Fm than leaflets that were restricted in movement The results indicate that the presence of a pulvinus at the base of each leaflet of carambola leaves allows movement of the leaflet to avoid incident light. This natural leaflet movement under sunny conditions results in a lower temperature and a higher level of photochemical efficiency when compared with leaflets that are exposed to high light due to restricting their movement.
125 THE ROLE OF ETHYLENE IN THE DEVELOPMENT OF CONSTANT-LIGHT INJURY OF POTATO
Authors: Cushman K. E. , Tibbitts T. W.
Published: February 2019

Chlorosis and necrotic spotting develop on expanding leaves of particular cultivars of potato (Solanum tuberosum L.) when grown under constant light and temperature conditions. Plantlets of a constant-light sensitive cultivar, Kennebec, were planted into peat:vermiculite and established at 18C for 10 d under a 12 h light: 12 h dark photoperiod. Plants were then exposed to constant light and sprayed with 1 ml of either 0.5 mM silver thiosulfate (STS), an ethylene-action inhibitor, or water (as a control) every 2 days. Specific `target' leaflets, 5-10 mm in length at the beginning of the constant-light period, were harvested on days 5-9 of constant light, during injury development, and placed in bags made of Teflon film for IO-15 minutes to collect ethylene. Ethylene release and necrotic spotting increased as days of constant light increased for both water and STS-treated leaves, though STS-treated leaves produced slightly less ethylene and significantly less necrotic spotting than water-treated leaves. Ethylene release was correlated with extent of necrotic spotting. STS-treated plants exhibited greater dry weight and leaf area then water-treated plants. The results indicate that ethylene is not only produced by injured leaf tissue but, in addition, that ethylene may have a role in the development of constant-light injury symptoms.
127 STEM PITH TISSUE FREEZING RESISTANCE IN CABBAGE (BRASSICA OLERACEA VAR.CAPITATA)
Authors: Manley Reeser C. , Hummel Rita L.
Published: February 2019

Winter survival of cabbage seed crops is limited by the freezing resistance of the lower stem pith tissue. Both tolerance of extracellular freezing and avoidance of lethal temperatures are components of stem pith tissue freezing resistance. The avoidance mechanism involves the formation of ice within the pith tissue at relatively warm temperatures (little undercooling) and the subsequent release of heat of fusion, followed by significant slowing of the freezing rate so that stem temperatures are mitigated against ambient temperatures for several hours.
128 POLLEN CHARACTERISTICS AND IN VITRO POLLEN GERMINATION OF TOMATOES GROWN AT HIGH NIGHT TEMPERATURES
Authors: Peet Mary M. , Willits Daniel H. , Bartholomew Michael
Published: February 2019

Previous greenhouse studies in Raleigh have shown that nighttime cooling increases tomato fruit weights from 11% to 53%, depending on planting dates. The physiological mechanism was unclear, except that temperatures during fruitset were most critical. We report here on 3 experiments, 2 in greenhouses and 1 in the phytotron, comparing pollen characteristics of plants grown at differing night temperatures. In the greenhouse studies, nighttime temperatures were kept below 20°C for either the whole night or just the last half of the night. In the phytrotron studies night temperatures were 18, 22, 24 or 26°C, In both phytotron and greenhouse studies, there was considerable day-to-day variability in pollen characteristics and % germination. The most consistent effect in both types of studies was a decrease in total pollen and an increase in % abnormal pollen at high night temperatures. In the phytotron studies 20°C appeared optimal for both these characteristics.