bluuebunny/crossref_metadata_2025 huggingface dataset:
492 Health Aspect of Using Recycled Treated Wastewater in Crop Production
Authors: Al-Ghawas S. , Al-Mazeedi K.
Published: February 2019

Treated wastewater will play important role in the implementation of Kuwait National Agriculture Development Plan. As a substitute for brackish or fresh water in irrigation, treated municipal wastewater can be a practical solution. Nevertheless, special health and environmental considerations should be carefully assessed when using this water source. These considerations include potential infection with human pathogens, effects of heavy metals on the public health, and the ecological consequence on soil and water resources at large. These topics were investigated under controlled environment using a range of crops and two types of irrigation water: a tertiary treated wastewater source and fresh tap water as a control. Soil, water, and plant samples were collected at fixed intervals and were analyzed for total viable count; total Coliforms; faecal Coliforms; and faecal Streptococc, Salmonellae, Shigella, Ascaris imbricoides and pathogenic viruses. In addition, we measured for nine heavy metals (Cd, Zn, Fe, Mn, Cu, Ni, Co, Cr, and Pb). Soil salinity and build-up of sodicity in soil and ground water sources also were investigated for any changes that could indicate a potential long-term degradation effect. The results after 3 years of study indicate that the generated tertiary treated wastewater is of high quality. Its potential pathogenic content is below the guidelines recommended by WHO for using wastewater in mixed agriculture, and therefore, it had no accumulative effect on the irrigated soil or the different parts of plant tissues that were analyzed. However, treated effluent have occasionally exhibited pathogenic index higher than permitted levels reflecting the fluctuating nature of wastewater treatment. Heavy metals content of irrigation water and from the irrigated soils were negligible, and the plant tissues that were analyzed contained metallic contents below the established range in IPE. The treated water had low TDS but high sodium content with 25–35 SAR values; however, the effect on the irrigated soil was insignificant due to the calcareous nature of the soil used. This study used drip irrigation system and under similar conditions no health problems will be expected when using tertiary treated wastewater for irrigation. To minimize potential risk to the consumers, specific guidelines are recommended on the type of crops to grow and the horticulture practices to be used.
496 Consumer Preference of Edible Flower Color, Container Size, and Price
Authors: Kelley K.M. , Behe B.K. , Biernbaum J.A. , Poff K.L.
Published: February 2019

Two surveys were conducted to determine the importance of characteristics of containers of edible flower which could be sold to consumers in retail outlets. Self-selected participants at Bloomfest at Cobo Hall in Detroit, Mich., were assigned to one group that rated the importance of attributes such as edible flower color of Viola × wittrockiana `Accord Banner Clear Mixture', color combinations, container size, and price of the container. Participants assigned to a second group rated color, color combinations, and size. Flower color was allocated the most points in the purchasing decision (63% for the first group and 95% for the second group), with a mixture of all three colors (blue, yellow, and orange), proving to be the most desirable. Responses were subjected to Conjoint Analysis (SPSS Inc., Chicago), which resulted in the formation of three groups of customer segmentation. The groups were labeled “Likely Buyer” who had eaten and purchased edible flowers before and rated characteristics of edible flowers favorably; “Unlikely Consumer” who had eaten edible flowers before and had rated characteristics of edible flowers unfavorably; and “Persuadable Garnishers” who had not eaten edible flowers before, but were very likely to purchase edible flowers for a garnish for a meal.
500 Evaluating the Benefit of Cutting Flower Stems Underwater
Authors: Suzuki Ayumi , Leonard Ria T. , Nell Terril A. , Barrett Jim E. , Clark David G.
Published: February 2019

It has traditionally been recommended to cut flower stems underwater to reduce blockage and improve water uptake, although little scientific information relates this practice to vase life. The purpose of our study was to evaluate the benefit of this processing technique on quality and longevity of several cut flowers species. Stems were either cut dry or cut wet under deionized water with a stainless steel blade and placed into vases containing a commercial floral preservative. Water samples were obtained from the cutting tank over time during stem processing for bacteria counts. Stems were maintained at 2 °C at 10 μmol·m–2·s–1 (12 h/day). The results were variable from shipment to shipment, possibly due to differences in stem quality or cutting water quality. In most cases, cutting underwater had no effect on longevity of alstroemeria, chrysanthemums, gerbera daisy, roses, or snapdragons. However, in a few instances, cutting underwater improved longevity slightly. Cutting stems underwater was consistently effective in increasing longevity 2-4 days for carnations. Bacteria counts in the cutting tank water after 500 stems were processed were 6/34 × 106 propagules/mL and increased to 1.00 × 107 propagules/mL after 1000 stems. The increase in bacteria decreased leaf quality in roses and reduced the number of snapdragon flowers that opened, but did not affect longevity. In gerberas, however, longevity decreased 2 days. A high concentration of bacteria in the cutting water may effect quality and longevity of many cut flower species and may negate any benefit in cutting stems underwater.
504 Urea Uptake and Nitrogen Mobilization by Apple Leaves in Relation to Tree Nitrogen Status in the Fall
Authors: Cheng Lailiang , Dong Shufu , Fuchigami Leslie H.
Published: February 2019

Bench-grafted Fuji/M26 trees were fertigated with seven nitrogen concentrations (0, 2.5, 5.0, 7.5, 10, 15, and 20 mm) by using a modified Hoagland solution from 30 June to 1 Sept. In Mid-October, plants in each N treatment were divided into three groups. One group was destructively sampled to determine background tree N status before foliar urea application. The second group was painted with 3% 15N-urea solution twice at weekly interval on both sides of all leaves while the third group was left as controls. All the fallen leaves from both the 15N-treated and control trees were collected during the leaf senescence process and the trees were harvested after natural leaf fall. Nitrogen fertigation resulted in a wide range of tree N status in the fall. The percentage of whole tree N partitioned into the foliage in the fall increased linearly with increasing leaf N content up to 2.2 g·m–2, reaching a plateau of 50% to 55% with further rise in leaf N. 15N uptake and mobilization per unit leaf area and the percentage of 15N mobilized from leaves decreased with increasing leaf N content. Of the 15N mobilized back to the tree, the percentage of 15N partitioned into the root system decreased with increasing tree N status. Foliar 15N-urea application reduced the mobilization of existing N in the leaves regardless of leaf N status. More 15N was mobilized on a leaf area basis than that from existing N in the leaves with the low N trees showing the largest difference. On a whole-tree basis, the increase in the amount of reserve N caused by foliar urea treatment was similar. We conclude that low N trees are more effective in utilizing N from foliar urea than high N trees in the fall.
511 Diagnosis and Management Strategies for Soilborne Apple Replant Problems in New York Orchards
Authors: Merwin Ian A. , Robinson Terence L. , Hoying Steven A. , Byard Rachel R.
Published: February 2019

We are evaluating the severity of apple replant disease (ARD)-characterized by stunted tree growth in replanted orchards, attributed to root pathogens and/or edaphic conditions-and testing preplant soil treatments for control of this wide-spread problem. Soil samples were collected during 1996–98 at 17 orchards in New York's major fruit growing regions and plant-parasitic nematodes and nutrient availability were quantified. Apple seedlings and potted trees on M.9 rootstocks were grown in fumigated and non-fumigated soil samples as a diagnostic bioassay for ARD severity. Factorial combinations of metam sodium, consecutive cover crops of Brassica juncea `Forge' and Sorghum sudanense `Trudan 8', and fertilizer/lime amendments were applied as preplant treatments at each orchard, 9 to 12 months before trees were replanted. Diagnostic bioassays indicated severe ARD at more than half the sites, and nematodes were not a major factor. Responses to preplant soil treatments were highly variable across the 17 farms. The best tree growth and yields followed preplant metam sodium at some sites, Brassica juncea and Sorghum sudanense at others, or fertilizer amendments at a few others. Tree responses to combined preplant soil treatments were often additive, and greater at irrigated sites. Comparisons of preplant diagnostic bioassay results with subsequent tree responses to metam sodium at the 17 orchards indicated that diagnostic tests predicted from 7% to 75% of tree growth response to soil fumigation, varying substantially across years and sites. It appeared that ARD was variable and site specific in New York orchards, and could not be controlled effectively with a uniform preplant soil treatment across our major fruit-growing regions.
543 Effect of Calcium and Sulfur on Yield of Late-storage Cabbage
Authors: McKeown Alan , Bakker Cathy
Published: February 2019

Soil and crop management practices suggest the possibility of sulfur deficiency for cole crops in Southern Ontario. A 3-year study was conducted to evaluate rates of calcium and sulfur on yield of `Huron' late-storage cabbage. Treatments were based on CaSO4 applied at 0, 1000, 2000, and 3000 kg·ha–1 `Novacal' (Ca 27%, S 19%, Mg 2.5%, Dolomex Inc., Portage-du-Fort, Quebec, Canada), a granulated gypsum product. Potassium sulfate and calcium nitrate were used as elemental controls. Potassium and nitrogen levels were balanced with potassium chloride and ammonium nitrate. Phosphorous applications were based on soil analysis. All treatments were applied pre-plant incorporated. This trial was repeated on sand and loam soils typical of soil used for cabbage production in southern Ontario. Applications of sulfur increased yield of cabbage on sand and clay, although the optimum rate varied from year to year. Medium and high rates produced the highest yield in the first year, while low rates were more effective in the second and third seasons. Response of cabbage to calcium varied from year to year. Medium and high rates of calcium increased yield on sand, but had no effect on clay in the first year. Calcium had no effect on yield on either soil type in the second year. However, in the third year, low rates of calcium produced the highest yield on both sand and clay. Although there were no visual symptoms of deficiency, applications of sulfur, and to a lesser extent calcium, increased yield indicating that a `hidden hunger' for these elements may exist on some soils in southern Ontario.
547 Nursery Crops for Nutrient Recovery in Treatment Wetlands
Authors: Holt Thomas , Maynard Brian , Johnson William
Published: February 2019

Constructed wetlands are an effective, low-cost method of water treatment that may reduce agricultural pollutants from nursery runoff. It has been suggested that the expense of implementing such systems could be recovered by growing aquatic plants that could be sold to retail and wholesale markets. However, this demand could probably be satisfied through a few wetlands. It would be desirable if more traditional nursery crops could be incorporated into treatment wetlands. Several taxa of Cannas, Iris, and ornamental grasses are selected cultivars of wetland plants that have been used in treatment wetlands for decades. However little data exists on these cultivar's nutrient uptake rates and survivability in treatment wetlands. Nutrient uptake and growth rates of Canna × generalis cultivars `Aflame', `King Humbert', and `Pretoria', Glyceria maxima `Variegata', Iris pseudacorus, Iris versicolor, Phalaris arundinacea `Luteo-Picta', Pragmites australis `Variegata', and Spartina pectinata `Aureo-marginata' were compared to the widely used Typha latifolia. Single divisions of each were established in a constructed wetland and batch fed weekly a commercial fertilizer solution reconstituted to 100 ppm-N. Plants were harvested after 75 days and biomass and tissue nutrient content was determined. Mean biomass of Typha latifolia was 212 g/division and nitrogen and phosphorus accumulation was 4.5 and 0.8 g/division, respectively. The biomass of the other species ranged from 101 to 175 g/division and had total accumulation of nutrients ranging from 2.5 to 3.8 g nitrogen/division and 0.35 to 0.85 g phosphorus/division.
548 Antitranspirant Treatments Affect Stock Plant Growth and Rooting Percentage in Two Members of the Oleaceae Family
Authors: Switras Susan , Gillman Jeffrey
Published: February 2019

Syringa vulgaris L. `Montaigne' (French hybrid lilac) and Chionanthus virginicus L. (white fringetree) stock plants were sprayed with two film-forming antitranspirants, Clear Spray and sodium silicate, and one stomate-regulating antitranspirant, atrazine. After 30 days of growth, cuttings were taken from both species. Shoot calipers of antitranspirant-treated lilacs increased at a slower rate than the control lilacs. There were no long-term shoot length changes in lilac due to antitranspirant treatments. Shoots of Clear Spray-treated fringetrees increased in length significantly less than other treatments. Rooting was evaluated once a week from week 3 until 6 weeks after cuttings were taken for lilac and every 2 weeks from week 6 to 12 weeks after sticking for fringetree. All treatments resulted in 80% to 85% rooting in lilac after 6 weeks, but Clear Spray-treated plants rooted more quickly. Fringetree cuttings treated with Clear Spray had a significantly lower rooting percentage (15%) than the other treatments (35% to 50%).
551 Inheritance of Tomato Late Blight Resistance Derived from Lycopersicon hirsutum LA1033 and Identification of Molecular Markers
Authors: Lough Rebecca C. , Gardner R.G.
Published: February 2019

During the last century Phytophthora infestans (Mont.) de Bary, which causes the devastating disease late blight of tomato and potato, has been controlled with pesticides. Recently, the difficulty of controlling late blight has increased due to the appearance of new strains of P. infestans that are more virulent and are resistant to metalaxyl. Numerous P. infestans resistance genes exist within the Solanaceae; however, most of these are race-specific and have the potential of being overcome. To achieve durable resistance, it may be necessary to utilize multigenic resistance or gene pyramiding. The Lycopersicon hirsutum Kunth accession LA1033 is highly resistant to P. infestans. To incorporate resistance into a useful background, the L. esculentum Miller inbred line NC215E was used as a recurrent parent in backcrossing with L. hirsutum LA1033. A population of 264 BC3F1 plants derived from 11 BC2F2 families was planted at Fletcher and Waynesville, N.C., in July 1998 in a replicated field trial. BC3F2 seed were collected from a single highly resistant BC3F1 plant. The BC3F2 population was tested for resistance using a detached leaf screen. To verify growth chamber test results, BC3F3 seeds were collected from the BC3F2 individuals and were planted in a field trial at Fletcher in July 1999. The ratio of resistant to susceptible progeny fit the expected ratio for an incompletely dominant trait controlled by two loci. To identify molecular markers linked to the resistance loci, DNA was extracted from the highly resistant and susceptible BC3F2 individuals, and bulks of DNA were constructed. The resistant and susceptible bulks were screened with AFLP (amplified fragment length polymorphism) markers. Results of the AFLP study indicate marker linkage to resistance.
552 Comparison of Genetic Diversity in between Two Germplasm Banks Containing Lycopersicon esculentum Accessions
Authors: Nienhuis James , Rodriguez Julie , Phillips Wilber , Hanson Peter , Engle Liliway
Published: February 2019

Worldwide, there are cuurently more than 60 germplasm banks that contain tomato (Lycopersicon esculentum) collections ranging is size from a few dozen to several thousands of accessions. In the utilization of these genetic resources sampling from only one germplasm bank may result in limiting available genetic diversity, whereas sampling from several germplasm banks may result in unnecessary redundancy. The current lack of knowledge regarding the relative magnitudes of genetic diversity contained within different collections makes it difficult to develop a core collection that maximizes genetic diversity. Two large tomato collections are housed at the Asian Vegetable Research and Development Center (AVRDC), Sanhua, Taiwan, R.O.C., and the Centro Agronomico Tropical de Investigacion y Enseoanza (CATIE), Turrialba, Costa Rica. Ninety-six accessions from CATIE and 102 accessions from AVRDC were randomly sampled from each base collection. The total of 198 accessions were charcterized for 103 polymorphic RAPD molecular marker bands. The results indicated that the two germplam banks sampled different genetic diversity. In addition, the magnitude of genetic diversity was greater in the AVRDC collection compared to CATIE.
555 Estimation of Genetic Diversity among Citrullus Accessions using RAPD Markers
Authors: Levi Amnon , Thomas Claude E. , Keinath Anthony P. , Wehner Todd C.
Published: February 2019

Genetic relatedness was estimated among 42 U.S. plant introduction (PI) accessions of the genus Citrullus (37 PIs of which were reported to have disease resistance and five watermelon cultivars) using 30 RAPD primers. These primers produced 662 RAPD markers that could be scored with high confidence. Based on these markers, genetic similarity coefficients were calculated, and a dendrogram was constructed using the unweighted pair-group method with arithmatic average (UPGMA). The analysis delineated three major clusters. The first cluster consisted of a group of five watermelon cultivars, a group of C. lanatus var. lanatus accessions and a group of C. lanatus var. lanatus accessions that contained some C. lanatus var. citroides genes. The second cluster consisted of the C. lanatus var. citroides accessions, while the third cluster consisted of the C. colocynthis accessions. The two C. lanatus clusters differentiated from each other and from the C. colocynthis cluster at the level of 58.8% and 38.9% genetic similarity. Our results indicate that closely related Citrullus PIs may have resistances to the same diseases. Thus, molecular markers may be a useful tool in the development of core collections of Citrullus PIs with resistance to diseases.
566 Barriers Encountered in Establishing Effective Distance Education Programs
Authors: Auld D.L. , Cepica M.J. , McKenney C.B.
Published: February 2019

Distance education is an area of rapid expansion in higher education today. Unfortunately, the development of distance education efforts, like all new programming, is fraught with numerous barriers. Frequently, technological advances precede internal policies necessary to support these activities, and because of the nature of distance education, concerns over expense, workload, intellectual property, conflict of interest and teaching methodology may impede progress. Funding distance education efforts also requires long-term vision and commitment. It is essential that a clear vision, including identification of existing needs and benefits, be developed before equipment and personnel are secured. Finally, some distance education efforts by their nature involve collaboration between other institutions of higher education. These schools may view participation in these programs as opportunities for their advancement or possible encroachment on their educational market. Establishing strong relationships is essential for ultimate success. At Texas Tech Univ., the College of Agricultural Sciences and Natural Resources along with the Dept. of Plant and Soil Science have committed to the development and implementation of distance education as an educational tool providing enrichment and access to high-quality programming for its on campus and place-bound students. Some of the success stories as well as the frustrations behind these efforts will be discussed.
568 Challenges and Opportunities in Academic Advisement for Non-traditional Horticulture Students
Authors: Fitzpatrick George E. , Klock-Moore Kimberly A.
Published: February 2019

The average undergraduate horticulture major at the Univ. of Florida Academic Program at Fort Lauderdale is 38 years old. The older, non-traditional student population is quite diverse, but many individuals are motivated by a desire to change careers, and many of them have taken extensive academic course work at other institutions prior to applying for admission to the Univ. of Florida. Academic advisement of this type of student presents a substantial challenge because of the uncertainty of content and vigor of prior academic preparation. To help meet this challenge, we have developed several academic advisement checklists that indicate numbers and titles of critical preprofessional and general education courses from the academic institutions that have been most frequently attended by the highest numbers of the incoming non-traditional students. These checklists have been cross-referenced between the catalogs of the various academic institutions and the Univ. of Florida catalog. We use these documents to evaluate the academic preparation of incoming transfer students and to assist them in making correct course selections to remedy any academic deficiencies that could negatively influence their success in upper division horticulture course work.
577 The Influence of Reflective Film and ReTain on Red Skin Color and Maturity of `Gala' Apples in South Carolina
Authors: Layne Desmond R. , Jiang Zhengwang , Rushing James W.
Published: February 2019

Replicated trials were conducted in summers of 1998 and 1999 at two commercial orchards (A and B) to determine the influence of a metalized, high-density polyethylene reflective film (SonocoRF, Sonoco Products Co., Hartsville, S.C.) and ReTain (Abbott Laboratories, Inc., N. Chicago, Ill.), on fruit red skin color and maturity of `Gala' apples. There were four experimental treatments: i) Control; ii) Reflective Film (RF); iii) ReTain; and iv) RF + ReTain. RF was laid 4 weeks before anticipated first pick date by laying a 5-ft-wide strip of plastic on either side of the tree row in the middle. ReTain was applied 4 weeks before harvest at the commercial rate in one orchard (A) and at 60% the commercial rate in the other orchard (B). At harvest, two 50-fruit samples were picked from each of four replicate blocks per treatment. All fruit were sized and visually sorted for color (1 = 0% to 25%, 2 = 26% to 50%, 3 = 51% to 75%, and 4 = 76% to 100% red surface, respectively). A 10-fruit subsample was selected following color sorting and evaluated for puncture pressure, soluble solids concentration (SSC) and starch hydrolysis. ReTain delayed maturity and reduced preharvest drop of `Gala'. Fruit from RF trees had a significantly greater percent red surface than fruit from trees not treated with RF. Fruit from RF + ReTain were significantly redder and had higher SSC than fruits from trees treated with ReTain alone. There were no differences in size, puncture pressure or starch hydrolysis between RF and RF + ReTain. RF appears to be a means to ensure greater redness in `Gala' treated with ReTain in South Carolina.
579 Thinning Nectarines and Peaches at Flowering with Organosilicone Surfactants
Authors: Klein Joshua D. , Cohen Shlomo
Published: February 2019

Thinning of nectarines and peaches is largely an expensive manual task. We investigated the use of organosilicone surfactants as thinning materials that can be applied by mechanized sprayers. Of the surfactants tested, Silwet-408 (Witco) and Boost (Dow-Elanco) were the most effective thinning agents. Spray concentrations of 0.1% or 0.25% (v/v) applied at 30% and 60% full bloom, or 0.5% applied at 80% to 90% bloom, reduced by 50% the mass of fruitlets that had to be hand-thinned and increased the average weight of harvested fruit by up to 20%. When 0.75% to 1% surfactants were applied at 80% to 100% full bloom, fruit yield was reduced by up to 90%. The sprays did not affect fruitlets that had set already, nor did they cause damage to leaves or young shoots. Open flowers were more susceptible to the surfactants than were flowers at tight-bloom or balloon stage. Ion leakage from both petals and flower bases increased in proportion to concentration of surfactant applied, but there was no increase in lipid peroxidation.
581 Effect of CPPU on Fruit Development in Seedless and Seeded Grape Cultivars
Authors: Zabadal T.J. , Bukovac M.J.
Published: February 2019

The effect of CPPU [forchlorfenuron; N-(2-chloro-4-pyridinyl)-N-phenylurea] on berry development of selected seedless and seeded grape cultivars was evaluated under field conditions. A concentration response curve was initially established by spraying clusters of `Himrod' at a mean berry diameter of 5 mm with 0, 5, 10, and 15 ppm CPPU. Berry enlargement was monitored (16, 30, 44, and 59 days after treatment) during development and cluster weight, berry number/cluster, weight, firmness and °Brix were determined at harvest. Berry size was dramatically (2.3 vs. about 3.6 g/berry) increased at harvest by all concentrations of CPPU; the response being linearly related to concentration (r2 = 0.89). Cluster weight and compactness (rated) and berry firmness were significantly increased. There was no significant effect on berry number (79 to 86/cluster). °Brix and rachis necrosis (at harvest) as well as berry abscission after 30 days of refrigerated storage were significantly reduced. Effect of time of CPPU application (0, 5, and 10 ppm) was established by treatment of clusters at mean berry diameters of 4, 5, 7, and 9 mm. Response was indexed by following berry enlargement at 14, 28, 42, and 56 (maturity) days after treatment. Maximum berry enlargement for both 5 and 10 ppm was obtained from applications at 4 to 7 mm in diameter. Relative responsiveness of seedless and seeded cultivars was compared by application of CPPU at 0, 5, 10, and 15 ppm to clusters (4–6 mm berry diameter) of seedless `Himrod', `Vanessa' and `Lakemont' and seeded `Concord' and `Niagara'. Bioresponse was determined by a time course of berry enlargement and berry and cluster weight, number of berries/cluster and rating cluster compactness at maturity. CPPU at all concentrations increased seedless berry diameter significantly from the first measurement at 14 days through 56 days after maturity. Berry and cluster weight and cluster compactness were increased in the seedless cultivars, although `Lakemont' appeared less responsive than `Himrod' and `Vanessa'. CPPU did not change (`Lakemont') or decreased (`Himrod', `Vanessa') berries/cluster. In contrast, the only effect of CPPU on the seeded cultivars was an initial increase in berry diameter 14 days after application.
587 Physiological Factors Limiting Tomato Fruitset at Moderately Elevated Temperatures
Authors: Peet M.M. , Sato S.
Published: February 2019

The effects of chronic, mild heat stress on fruit set, fruit production, release of pollen grains, photosynthesis, night respiration, and anther dehiscence were ex-amined in tomatoes (Lycopersicon esculentum Mill.) differing in high temperature sensitivity. Plants were grown under three temperature regimes: 1) 28/22 or 26/22 °C (optimal temperature) 2) 32/26 °C (high temperature), and 3) 32/26 °C day/night temperatures relieved at 28/22 °C for 10 days before anthesis, then returned to 32/26 °C (relieving treatment). `FLA 7156' was the only cultivar with fruit set at 32/26 °C. All five cultivars, however, had fruit set in the relieving treatment (RT). The longer the relief, the higher was the percentage of fruit set. Longer periods of relief also increased the number of pollen grains released and linear regression analysis showed a significant relationship between the number of pollen grains released and the percentage of fruit set. Germination of pollen grains was also lowered in high-temperature-grown plants. The number of pollen grains produced, photosynthesis, and night respiration did not limit fruit set under chronic, mild heat stress, however. This suggested that cultivar differences in ability to release pollen and to produce viable pollen under heat stress are the most important factors determining their ability to set fruit.
588 Moisture Balance in Dry-heat-treated Vegetable Seeds
Authors: Lee Jung-Myung , Kim Du-Hyun
Published: February 2019

Dry-heat (DH) treatment has been extensively used for inactivation of some seed-borne virus and Fusarium disease in many vegetable crops, especially in cucurbitaceous vegetables. Strains of tobamovirus (cucumber green mottle mosaic virus; CGMMV) could be successfully inactivated by treating the infected seeds at 75 °C for 72 h. However, DH-treated seeds frequently exhibit slow and poor germination and abnormal seedling characteristics, such as distorted, white streaked, and punctured cotyledons in the seedlings. The moisture content in seed coat and inner cotyledons fell down to below 1% in DH-treated seeds when treated at 75 °C or higher. However, when the seeds were treated at 65 °C, final moisture content in the DH-treated seeds were maintained at about 2.5% to 3.5%. Seeds absorbed moisture above 20% at 100% RH, 9% to 10% at 73% RH, and 4% to 5% at 28% RH, respectively. When the intact and DH-treated seeds were exposed to conditions of varying relative humidity, DH-treated seeds absorbed atmospheric moisture at a much slower rate than the intact seeds in all tested cultivars, and this is thought to be one of the major reasons for slower germination in DH-treated seeds. The inactivation of virus, comparison of respiration of seeds, and endogenous gibberellic acid contents will also be presented.
589 Calcium Application at Preemergence and during Bulking May Improve Tuber Quality and Grade
Authors: Gunter Christopher , Ozgen Senay , Karlsson Bjorn , Palta Jiwan
Published: February 2019

An increase in calcium concentration of potato tuber tissue has been shown to reduce soft rot severity and the incidence of internal physiological defects. Higher tuber calcium also seems to increase sprout vigor and maintain apical dominance by reducing subapical necrosis and sprout tip death. Preemergent applications of calcium at a rate of 0 and 26.5 kg·ha–1 from ammonium nitrate (PreAmNit), ammonium nitrate plus calcium nitrate (PreCaN), or calcium chloride plus calcium nitrate plus urea (PreCUC). A group of post-emergent split calcium nitrate plus calcium chloride plus urea (PostCUC) applications beginning with hilling and proceeding at 3, 6, and 8 weeks after hilling were also made at a rate of 56 kg·ha–1 calcium at each application time. From visual ratings of stand quality taken 64 days after hilling, we found plants receiving a preemergent application of nutrients or PostCUC had higher stand ratings than paired control plots. Internal tuber quality ratings revealed less internal brown spot in the PostCUC application in 168–364-g tubers. Yield of 112–168-g tubers was greatest from plants treated with PreCaN or PreCUC followed by PostCUC. PreAmNit plots had higher culls than the PreCUC plots. The non-split ammonium nitrate control (all nitrogen by hilling) produced a higher number of B-sized tubers than the PostCUC treatment. Also the PreAmNit+PostCUC had more B-sized tubers than PreCaN+PostCUC. In general the PostCUC treatment produced fewer small tubers and more large tubers than other treatments. These results suggest application of a small amount of calcium prior to emergence but after the sprouts have begun to develop improves seed performance. Furthermore these data show that supplemental calcium application during the season may improve tuber grade.
595 Computer Root Image Analysis of Citrus Rootstock Seedlings
Authors: Tignor Milton E. , Stoffella Peter J.
Published: February 2019

Florida citrus has had an average annual on-tree-value of ≈1 billion dollars during the past decade in Florida. Nearly all of the 845,260 acres of citrus in Florida is produced on grafted trees consisting of a commercial scion cultivar and a rootstock selected specifically for local soil, environment, and pest pressures. With vastly different root-zone environments, ranging from deep sands to drained and cleared pine Flatwoods, a large number of different rootstocks are utilized. These rootstocks are started from seed at more than 100 commercial nurseries statewide, which currently produce an estimated 6 million trees a year. Although the optimum germination conditions, basic physiological performance, and adaptability of many rootstocks are known, there has been minimal investigation on early root development in seedling trays at the nursery. Four hundred seedlings of `Swingle' citrumelo (Citrus paradisi Macf. `Dunacn' × Poncirus trifoliata), `Smooth Flat Seville', `Volkamer' lemon (Citrus volkameriana), and `Sun Chu Sha' mandarin were seeded in a randomized block experimental design and grown at a commercial nursery. Seedling root systems (100/rootstock) were analyzed for a number of variables using the Rhizo (Regent Instruments, Inc.) software package and a dual light source scanner. Using the SAS general linear model procedure, hypothesis testing revealed rootstock selection had a significant effect on total root length, total root surface area, total root volume, number of root tips, number of root forks, root dry weight, and stem diameter. For most characteristics, rootstock genotype accounted for a greater portion of variability than samples (plant to plant variability).
597 Rootstock and Scion Interact to Affect Apple Tree Performance: Results from a 10-year Trial by the NC-140 Technical Committee
Authors: Autio Wesley R.
Published: February 2019

In 1990, trials were established at 13 sites including `Golden Delicious', `Jonagold', `Empire', and `Rome' apple cultivars in all combinations on M.9 EMLA, B.9, Mark, O.3, and M.26 EMLA rootstocks. After 10 growing seasons, rootstock and cultivar interacted significantly to affect trunk cross-sectional area and yield efficiency but not yield per tree or survival. Generally, trunk cross-sectional area was greatest for M.26 EMLA, followed by O.3, M.9 EMLA, B.9, and Mark. However, differences between B.9 and Mark and between M.9 EMLA and O.3 varied with cultivar. B.9 was 34% to 46% larger than Mark with `Golden Delicious' and `Empire,' but they were similar for `Jonagold' and `Rome.' O.3 was 27% larger than M.9 EMLA with `Golden Delicious' and `Empire,' they were similar for `Rome', and O.3 was 12% smaller than M.9 EMLA with `Jonagold'. M.26 EMLA resulted in the greatest cumulative yield per tree, followed by O.3, M.9 EMLA, B.9, and Mark. Generally, cumulative yield efficiency (1992–99) was greatest B.9 and Mark and least for M.26 EMLA. M.9 EMLA and O.3 were similar and intermediately efficient. However, differences between B.9 and Mark and between M.9 EMLA and O.3 varied with cultivar. M.9 EMLA and O.3 were similarly efficient with `Golden Delicious', `Jonagold', and `Rome,' but M.9 EMLA was 11% more efficient than O.3 with `Empire'. B.9 and Mark were similarly efficient with `Golden Delicious' and `Jonagold', but Mark was 15% more efficient and 25% less efficient than B.9 trees with `Empire' and `Rome', respectively. Site played an important role, but survival was best for B.9 and poorest for O.3. Cooperators included: J.L. Anderson, W. Autio, J. Barden, G. Brown, R. Crassweller, P. Domoto, A. Erb, D. Ferree, A. Gaus, R. Hayden, P. Hirst, F. Morrison, C. Mullins, J. Schupp, and L. Tukey.
612 The Relationship of Pollen Development and Release to Fruit and Seed Production in Tomato Cultivars Exposed to Heat Stress at Varying Humidity Levels
Authors: Peet M.M. , Clement C. , Sato S.
Published: February 2019

Starting 2 weeks before anthesis of the first flower, tomato cultivars (Lycopersicon esculentum Mill.) differing in heat tolerance were exposed to mild heat stress (31/24 vs. 28/22 °C) at three levels of relative humidity (30%, 60%, and 90%) in controlled environment chambers at the Duke Univ. Phytotron. Pollen development in the anthers was followed cytologically, pollen release was measured at anthesis, and seed production and fruit weight were measured as fruit matured. Fruit and seed development were best at 60%RH and 28/22 °C and worst at 90% RH and 31/24. Seed development was poor at 31/24 °C at all humidity levels. It was also poor at 28/22 in the 90% RH treatment. Low relative humidity had a greater negtive effect on fruit and seed production and on cytological development in plants grown at high temperature. Pollen release was also reduced at 90% RH, with virtually no pollen released at 31/24 °C. Cytological examinations revealed developmental anomolies in pollen in some, but not all cultivars at 90% and 30% RH. Plant height was also affected by the treatments, with much taller plants in the high-temperature, high-humidity treatments.
615 Colored Shade Nets can Manipulate the Vegetative Growth and Flowering Behavior of Ornamental Plants
Authors: Oren-Shamir M. , Gussakovsky E.E. , Shpiegel E. , Matan E. , Dory I. , Shahak Y.
Published: February 2019

Many green-decorative branches (“Greens”) and cut flowers are commercially grown under shade nets, for both the reduction of the natural intercepted sunlight as well as physical protection. The most commonly used are black nets, which do not affect the visible light spectrum. In the work presented here we have studied the effects of shade nets of varying optical properties on the vegetative and flowering responses of ornamental plants, searching for nets that will specifically induce a desired behavior, thus gaining benefits in addition to the mere shading. Nets of different transmittance spectra, light scattering, reflectance and thermal properties are being studied for their effect on the vegetative growth of several Greens: Pittosporum variegatum, Ruscus hypoglossum, and Leather-leaf fern. The knitting density of all nets has been adjusted to have the same percent shading in the PAR (photosynthetically active radiation) range of the spectrum for all nets investigated. Experiments were carried out in commercial plots. Data were collected for microclimate, physiological and horticultural parameters. The main results obtained so far: i) pronounced stimulation of the vegetative growth under the Red net; ii) dwarfing by the Blue net; iii) the Grey net markedly enhanced branching, yielding “bushy” plants with short side branches; iv) the reflective, thermal net (Aluminet®) enhanced side, long branching (in Pittosporum). Recently we have applied a similar approach to cut flowers such as Lupinus luteus, Lisianthus eustoma, and Dubium ornitugalum, and obtained dramatic effects of some of the nets on both the vegetative development and flowering behavior. The results to be presented, suggest that sophistication of the use of shade nets can lead to better agricultural performance.
619 Cold Pretreatment, Planting Depth, and Shade Affect Cut Stem Quality and Perennialization of Field-grown Dutch Bulbs
Authors: Cavins Todd J. , Dole John M.
Published: February 2019

Hyacinthoides hispanica (Mill.) Roth., Hyacinthus orientalis L. `Gypsy Queen', Narcissus pseudonarcissus L. `Music Hall', N. pseudonarcissus `Tahiti', Tulipa gesneriana L. `Couleur Cardinal', and T. gesneriana `White Emperor' bulbs were given 0 or 6 weeks of preplant 5 °C cold treatment and planted 15, 30, or 45 cm deep into raised ground beds under 0%, 30%, or 60% shade. Plant growth was monitored for 2 years after planting. Preplant 5 °C cold pretreatment reduced percentage of Tulipa `White Emperor' bulbs that flowered but did not affect the percentage of bulbs that flowered for the other species. Cold pretreatment also delayed anthesis in one or both years for all cultivars except Hyacinthoides hispanica. The greatest percentage of bulbs flowered when planted 15 cm deep. The 45-cm planting depth reduced bulb flowering percentage or eliminated plant emergence. Increasing planting depth increased days to anthesis for all cultivars in both years. Increasing shade increased stem lengths in year 2 for all cultivars except Hyacinthoides hispanica, but did not influence percentage of bulbs flowering for any cultivars. For all cultivars perennialization was low regardless of treatment as less than 30% of bulbs survived to the 2nd year.
622 Initiation of Flowering, Runner Formation, and Carbohydrate Distribution in Strawberry (Fragaria × ananassa Duch.) Mother and Daughter Plants Grown at Different Temperatures
Authors: Kirschbaum D. , Cantliffe D.J. , Chandler C.K. , Darnell R.L.
Published: February 2019

The present research was undertaken to examine carbohydrate composition and distribution patterns and induction of flowering and runner formation in attached and detached strawberry plants grown under varying temperature conditions. There was an interaction between attached mother and daughter plants. Daughter plants affected flowering in mother plants, and mother plants influenced vegetative growth in daughter plants. Attachment and high temperature decreased root soluble carbohydrate concentration and promoted runner formation in both mother and daughter attached plants, suggesting that changes in carbohydrate concentration in the roots may be correlated with changes in vegetative growth. According to the results of this research, high temperatures are likely to enhance vegetative growth, whereas lower temperatures are likely to enhance the floral response. Differential temperature regimes applied to the mother/daughter plant experimental system could be an alternative to photoperiod treatments as a tool to study the correlation between environmental conditions and changes in vegetative and reproductive growth in strawberry.
624 Nitrate and Iron Reductase Activities in Vaccinium Species
Authors: Poonnachit Umpika , Darnell Rebecca L.
Published: February 2019

Vaccinium corymbosum, one of the cultivated blueberry species, is not well-adapted to mineral soils, which are generally marked by high pH, the predominance of NO3-N over NH4-N, and limited iron availability. A wild species, V. arboreum, grows naturally on mineral soils, and thus may be better adapted than V. corymbosum. This adaptation may be related to the ability of V. arboreum to assimilate NO3 and/or iron more efficiently than V. corymbosum. Both species were grown in a hydroponic solution containing 5.0 mM N as (NH4)2SO4 or NaNO3, and buffered to pH 5.5. Nitrate reductase (NR) and iron reductase (FeR) activities were measured. NR activity was higher in V. arboreum compared with V. corymbosum when grown with N03-N, while no difference between species was observed when grown under NH4-N. Activity of FeR was higher in V. arboreum compared with V. corymbosum, and higher under NO3-N compared with NH4-N. After 5 months in hydroponics, Fe was removed from one-half of the solutions. The activity of NRA in both species was higher under Fe-sufficient compared with Fe-limited conditions, but in both cases, activity was higher in V. arboreum compared with V. corymbosum. FeR activity continued to be higher in V. arboreum compared with V. corymbosum, and under NO3 compared with NH4-N. Activity decreased in both species under limited Fe conditions, and there were no interactions between species and Fe. These data indicate that V. arboreum possesses higher NR and FeR activities than V. corymbosum, under both Fe-sufficient and Fe-limited conditions. This may play a role in the better adaptability of V arboreum to mineral soil conditions.
627 Harvester Adjustments Substantially Increase Fruit Yield and Quality for the Split Versus Conventional Trellis in Red Raspberry
Authors: Klauer Stephen F. , Chen Chuhe , Cameron J. Scott
Published: February 2019

In 1999, yield of the split (ST) vs. conventional trellis (CT) was again compared in “Meeker” red raspberry. Field-testing was repeated at four sites in north (Lynden) and southwest (Woodland, Ridgefield, WSUV REU) Wash. A variety of widths, crossarm styles, and machine harvesters were tested in fields with varied cultural practices. Topped and tied-over canes were compared at two locations. In previous years, estimated yield potentials have been 20% to 60% greater for ST, but actual yields have only been 10% to 13% greater because of harvester damage to laterals and premature pick of green fruit. This year, Littau Harvester suggested minor machine adjustments that addressed these problems, resulting in a 19.4% yield increase for a 51-cm ST (Lynden). Lateral damage was minimized by spreading the picking heads to begin harvest, and then moving them closer after every three harvests. Excessive green fruit was controlled by reducing beater rod speed. A rough cost/benefit analysis indicates that there would be substantial economic gain (15% more $/acre in this case, assuming $0.50/lb fruit) for ST vs CT at this level of yield increase. There was no difference in harvest efficiency between treatments at WSUV. More fruit was lost to drop in the row center for ST in Lynden. Topped canes in CT and ST had reduced yields of 11 and 19% respectively compared to their tied-over counterparts. Topped ST canes had 11% greater yield than topped CT canes. ST canopies were larger, and had more leaves than CT. No differences were seen on a leaf-area basis between treatments for leaf: CO2 assimilation, fluorescence, and chlorophyll or in primocane leaf total nitrogen. Increased ST yields were recorded for a 2nd year at two locations, which supports yield sustainability for ST.
628 Effect of Air Temperature on Growth Regulators in the Induction of Cold Hardiness in Blueberry
Authors: Panicker Girish K. , Matta Frank B. , Gerard Patrick D.
Published: February 2019

Air temperature on crop productivity is a complex topic in environmental physiology. Blueberry growers in the Southeastern United States experience major crop losses due to late spring frosts. A 2-year study was conducted on `Tifblue' rabbiteye blueberry flower flushes to determine the effect of abscisic acid (ABA) at 0, 20, 40, and 60 mg·L–1 and paclobutrazol at 0, 100, 200, and 300 mg·L–1 on cold hardiness of floral parts. Two types of flower flushes were identified in `Tifblue'. Critical freezing temperatures and the effectiveness of the treatments were determined by differential thermal analysis (DTA), electrolyte leakage (EL), oxidative browning and tetrazolium staining. Floral parts frozen to –40 °C produced only one exotherm, confirming that rabbiteye floral parts do not supercool. Both growth regulators were more efective in the induction of hardiness in floral parts at second flush than at first flush. Floral parts developed in April were more prone to freezing injury than the floral parts of March. Ovaries were the hardiest, followed by calyx, stamen, style, and corolla. Air temperature had a profound influence on cold hardiness as influenced by ABA and paclobutrazol. The sequence of exotherms of DTA and the LT50 of the viability tests were air temperature-dependent.