bluuebunny/crossref_metadata_2025 huggingface dataset:
MANAGEMENT AND CULTURAL PRACTICES OF IRISH POTATO AND SWEET POTATO AND THEIR EFFECT ON SOIL LOSS
Authors: Cole-Crosby Iris , Harness Jesse , Igbokwe Patrick
Published: February 2019

The cultural and management practices for Irish Potato and Sweet Potato were monitored, along with various plant growth parameters. Data was collected on row width, plant spacing, irrigation, root mass, plant population, vegetative dry matter, canopy height, yeild, above ground biomass, root depth, canopy cover, leaf area index, and stem diameter. Climatic parameters such as rainfall, average daily temperatures, and growing degree days. The data was imputed into the erosion prediction model WEPP (Water Erosion Prediction Project) and the annual soil loss was compared between the crops. Results suggest that Irish Potato is better crop for conserving soil.
EFFECTS OF HYDROPHILIC POLYMERS AND ORGANIC AMENDMENTS ON ESTABLISHMENT OF KENTUCKY BLUEGRASS.
Authors: Downer A. James , Faber Ben , White Richard
Published: February 2019

Three polymers (a polyacrylamide, polyacrylate and a propenoate-propenamide copolymer) and three organic amendments (peat moss, wood shavings, and composted yardwaste) were incorporated at five rates in a sandy soil to 15cm depth. Soil moisture content was determined by time domain reflectometry and gravimetrically. Only the highest polymer rates (2928kg/ha [60#/1000sq.ft.]) produced significant increases in soil moisture content and reductions of soil bulk density. Peat moss and yardwaste increased soil water content while shavings decreased water content. Turf quality scores were not affected by polymers but were initially reduced by yardwaste and shavings.
A MODEL SYSTEM FOR DETERMINING CHEMICAL MOVEMENT THROUGH GOLF COURSE GREENS
Authors: Smith Albert E. , Corley Will
Published: February 2019

Lysimeters were developed in the greenhouse for simulating golf course greens with `Tifdwarf' bermudagrass and `Penncross' bentgrass overlying USGA specified rooting substratum. The lysimeters were constructed by subtending wooden flats containing turfgrass (38 × 38 × 14 cm deep) with polyvinyl chloride tubes (15 cm diam. × 52 cm deep) containing USGA-recommended rooting mixture for each turfgrass. The base of the tubes was capped with a closure containing an exit port for collecting the effluent drainage. An automatic irrigation system was developed by mounting flat fan nozzles on a cable driven roller 55 cm above the grass sod. The automatic water system is calibrated to irrigate at a rate of 0.1 cm min-1 for predetermined time-periods and volumes. The water flow through the lysimeters is uniform with a coefficient of variation less than 10% for 36 lysimeters. Data on chemical movement following treatment with three herbicides and weekly applications of fertilizer will be presented.
OPPORTUNITIES FOR OPTIMISM: GLOBAL HORTICULTURE
Authors: Cathey H. M.
Published: February 2019

Horticulture has entered the 90's with a different set of priorities and opportunities for its crops and knowledge. We no longer pursue science solely for the knowledge acquired and published, we are now permitted to receive compensation for our intellectual properties. Unique plants and processes thus have potential for marketing internationally. These shifts in professionalism will affect the decisions as to which crops and disciplines our scientists select to follow. Applications of the new technology must be redefined to avoid whimsical use of the techniques. Our programs must be directed toward products which are truly exceptional with high quality and performance. Until horticulturists have the information relating to the consumer preferences in new markets, plants cannot be created, exported and marketed successfully overseas. The U. S. industries have climate, transportation, and skilled technicians available to support our global export of our horticultural excellence. I will discuss a specific program under review for florist and nursery agriculture.
NEW ZEALAND HORTICULTURAL EXPORTS
Authors: Turner D. H.
Published: February 2019

New Zealand horticultural exports expanded rapidly during 1970-1990. These increases did not occur without some difficulties. Details of the export expansion including main products and major markets (such as the U. S. and Pacific Rim Countries) will be discussed. Key factors such as: 1) marketing strategies of the past, present, and future; 2) the impact of new marketing technology; and 3) importance of New Zealand image will be detailed. The role of education and technology and the skill level of New Zealand horticulture will be reviewed. This will include the New Zealand tertiary education system as well as relevant examples of how universities can assist.
HORTICULTURE AND THE GLOBAL MARKET
Authors: Gomez Ricardo E.
Published: February 2019

The future competitiveness of any nation, including its agriculture, is inextricably tied to understanding and effectively participating in global markets. Major opportunities exist for farmers to produce, process, and export agricultural products, especially value added products, if they had knowledge of global opportunities. Most of the information and services are available for them to achieve this objective. The Cooperative Extension System (CES) can provide a mechanism to deliver educational programs on global marketing opportunities and training on procedures for capitalizing on these opportunities. County agents from Virginia and California working with their mushroom producers helped them respond to a year round shitake order from the United Kingdom. This has resulted in an ongoing market for these producers. Other similar examples in horticulture will be discussed.
EVALUATION OF OWN-ROOTED AND JUNE-BUDDED 'REDHAVEN' PEACH TREES AT TWO HEADING HEIGHTS
Authors: Wolfe Dwight , Brown Gerald
Published: February 2019

`Redhaven' peach [Purnus persica (L.) Batsch] trees which were either own-rooted (OR) or June-budded (JB) the previous year were headed back at planting to either (1) 70-85 cm above the soil surface (CH, conventional heading) or (2) the first bud 20-30 cm above the soil surface (LH, low heading). Propagation method had no effect on fruit yield in 1988 or trunk cross-sectional area; however, total yield in 1987, and the cululative yield for 1987 and 1988 were significantly greater for JB trees than for OR trees. LH reduced survival of OR trees, but not the JB ones. Cold injury was greater for the OR trees than for the JB ones. Neither propagation nor heading height influenced bloom density, fruit set in 1987, or fruit size in 1988. However, OR trees which were conventionally headed produced larger fruits in 1987 than did JB trees the same year.
SUGAR METABOLIZING ENZYMES IN CARROT ROOTS FROM POPULATIONS VARYING IN SUGAR TYPE AND CONCENTRATION
Authors: Simon Philipp W.
Published: February 2019

Four carrot populations with low total sugar/low reducing sugar concentration, low total sugar/high reducing sugar concentration, high total sugar/low reducing sugar concentration, and high total sugar/high reducing sugar concentration were compared for pH 4.5 invertase, pH 7.5 invertase, sucrose synthase, and sucrose phosphate synthase activity. Invertase activities correlated well with reducing sugar concentration. Sucrose synthase and sucrose phosphate synthase activities were low in all populations. Total sugar level was not well-correlated with the activity of any enzyme measured. Developmental analysis indicated some reduction in enzyme activity as roots grew.
ROOT RESTRICTION AND SHADING EFFECTS ON SUMMER SQUASH
Authors: NeSmith D. Scott
Published: February 2019

Summer squash (Cucurbita pepo L.) was grown under greenhouse conditions in 0.35, 2.00, or 7.60 liter containers with full light or with 50% full light to determine the effects of root restriction and reduced light on crop growth and development. Leaf area was determined nondestructively over the course of the experiment, and destructive plant samples were taken weekly to determine dry matter accumulation and partitioning. The experiment was repeated to validate results. There was a decline in production of plant leaf area and dry matter accumulation in response to increased root restriction under full light conditions. However, under 50% light, root restriction had less impact on plant growth when comparing the 2.00 and 7.60 liter container plants. Under the most severe root restricting conditions, light level had little impact on leaf area production and dry matter accumulation. There were no consistent differences in leaf chlorophyll attributable to root restriction or reduced light; however, there was a trend for decreased leaf weight per unit of leaf area under low light conditions. Fruit dry matter production was notably diminished under severe root restriction in full light, and under all root environments under 50% light.
ROOT AND SHOOT GROWTH AS INFLUENCED BY OVERHEAD AND FLOATATION IRRIGATION IN JALAPENO PEPPER TRANSPLANTS
Authors: Leskovar Daniel I. , Heineman Ronald R.
Published: February 2019

This study was conducted to investigate how irrigation systems alter root elongation, root morphology, shoot growth characteristics and yield of `TAM-M' jalapeno pepper seedlings. Transplants were grown in containerized trays (18 cm3/cell) for 6 weeks in a greenhouse in Spring 1991. Irrigation systems were: a) floatation (FI), b) 4-week floatation plus 2-week overhead (FI+OI); c) alternate floatation and overhead (FI/OI), and d) overhead (OI). The growing media was maintained between 50 and 20% of its water holding capacity. Between 20 and 41 days after seeding (DAS), FI and FI/OI transplants maintained a constant lateral root length increase. In both FI+OI and OI transplants, lateral root elongation response tended to a `plateau' at ≈ 31 DAS. However, between 31 and 41 DAS, OI transplants had a root growth compensation, increasing the number and length (33%) of basal roots. In FI+OI transplants, basal root growth compensation occurred later in the field. At planting, OI transplants had higher shoot/root ratio (S:R=5) and maintained a higher shoot water potential (ψ= -0.58 MPa) than FI transplants (S:R=3; ψ= -0.69 MPa), respectively. Overhead-irrigated transplants had higher early fruit yields than floatation-irrigated transplants, but total yields were unaffected.
DETERMINATION OF LOW OXYGEN TOLERANCE LIMITS FOR SEVERAL APPLE CULTIVARS
Authors: Gran Christopher D. , Beaudry Randolph M.
Published: February 2019

The oxygen partial pressure associated with the respiratory quotient (RQ) breakpoint (ie., lower oxygen limit) was determined for fruits of several apple cultivars stored at 0°C. Fruits were sealed in low density polyethylene pouches of various thicknesses and known permeability to determine O2 uptake, CO2 production, and respiratory quotients (RQ) at various O2 partial pressures. There were differences in the shape of O2 uptake versus steady state O2 curves between cultivars. While some cultivars showed steady declines in respiration rate from 8 kPa O2 to < 1 kPa, other cultivars showed no decline in respiration until O2 levels fell below 3 to 4 kPa. Fruits having elevated RQ values had greater levels of headspace ethanol in the polyethylene pouches, which confirmed anaerobic respiration. The lower oxygen limit ranged from a low of approximately 0.75 kPa for cultivars Northern Spy and Law Rome to high of 1.5 kPa for McIntosh.
FOLIAR POTASSIUM SPRAY TIMING EFFECTS ON SEASONAL LEAF POTASSIUM AND PRODUCTIVITY OF FRENCH PRUNE (PRUNUS DOMESTICA)
Authors: Southwick S.M. , Olson W. , Yeager J.
Published: February 2019

Soil applied potassium (K) may not alleviate K deficiency in fine textured California soils when high numbers of prunes per tree are produced leading to leaf necrosis and limb death. Because K demand is increased by fruit, K nitrate (KN) sprays appear to be a corrective option for growers in this situation. Our objectives were to determine best seasonal KN spray liming strategies to minimize K deficiency, quantify K uptake into leaves after spray and to evaluate spray effects on productivity. Results indicated that regardless of spray timing leaf K was increased by approximately 0.3% and three weeks later decreased 0.2%. Average leaf K in sprayed trees was 0.7% higher than untreated trees at harvest. Fruit fresh to dry weight ratios were lower (better) from summer sprayed trees than spring. Summer KN sprayed trees had yield efficiencies equal to those having soil applied K. Fruit size was similar regardless of K application method. Foliar KN sprays may be a viable K augmentation to soil application in heavy crop years on fine textured soils.
EFFECTS OF NITROGEN RATE AND APPLICATION DATE ON GROWTH, YIELD, AND MINERAL COMPOSITION OF NECTARINE LEAVES AND FRUIT
Authors: Marangoni B. , Scudellari D. , Toselli M.
Published: February 2019

Mature trees of Stark Redgold nectarines grown in silt loam soil in the Po Valley were tested at five fertilization regimes and compared to untreated control: N1 (100 kg N/ha), N1 (100 kg N/ha, split 60% in spring and 40%. in postharvest), N2 (200 kg N/ha), N1 (100 kg N/ha) + K (150 kg K2 0/ha), N2 (200 kg N/ha) + K (150 kg K2 O/ha). The annual distribution in spring was equally split before full bloom and at fruit set.

The data collected over the three trial years show no differences as compared to control in yield and fruit size. N2 delayed ripening and decreased fruit quality. Leaf mineral composition was affected by potassium; maximun N induced leaf accumulation of N-NH4 The high concentration of K in leaf tissues was correlated to the yellow color of the leaf blade. Total leaf chlorophyll content was measured by an Spad-502 chlorophyll meter (Minolta Corp.) and compared to that measured by conventional technique (Arnon method). The overall findings suggest the amount of N used in peach fertilization can be reduced.
FERTILIZER EFFECTS ON EARLY GROWTH AND YIELD OF 'HAMLIN' ORANGE TREES
Authors: Obreza Thomas A. , Rouse Robert E.
Published: February 2019

The growth response of newly-planted 'Hamlin' orange (“Citrus sinensis L. Osbeck) on Carrizo citrange (C. sinensis × Poncirus trifoliata L. Raf.) trees to N-P-K fertilizer rates was studied to determine the minimum fertilizer required to bring trees into maximum early production. The highest fertilizer rate applied was 2.72, 5.45, and 8.17 kg·tree-1 of an 8-1.8-6.6 N-P-K fertilizer in 1989, 1990, and 1991, respectively. Additional fertilizer treatments equalled 50, 25, or 13% of the maximum rate. The response of trunk cross-sectional area, tree canopy volume, and fruit yield to fertilizer rate was described by a linear plateau model. The model predicted a fruit yield of 22.6 kg·tree-1 at the estimated critical rate of 48% of maximum. Fruit yield at 50% of maximum rate averaged 21.2 kg·tree. As fertilizer rate increased, total soluble solids (TSS) in juice and ratio (TSS:acid) decreased, but weight per fruit and TSS per tree increased. A fruit yield above 21 kg·tree-1 from 31-month-old trees was indicative of vigorous growth.
FLOODWATER OXYGEN CONTENT, ETHYLENE PRODUCTION AND LENTICEL HYPERTROPHY IN FLOODED MANGO TREES
Authors: Larson Kirk D. , Schaffer. Bruce , Davies Frederick S.
Published: February 2019

The influence of floodwater dissolved O2 content on stem lenticel hypertrophy and endogenous ethylene evolution from mango trees, and the influence of exogenous ethylene on mango stem lenticel hypertrophy was examined. In general, floodwater O2 contents of 1-7 ppm resulted in lenticel hypertrophy within about 6 days of flooding, whereas floodwater O2 contents of 15 ppm delayed hypertrophy until about day 9. After 14 days of flooding, there were more than twice the number of hypertrophied lenticels per tree with floodwater O2 contents of 1-7 ppm than with O2 contents of 15 ppm. Ethylene evolution from aerobic stem tissue increased 4- to 8-fold in trees exposed to floodwater with 1-2 ppm O2, increased 2-fold for trees exposed to 6-7 ppm O2, but remained constant with 15 ppm floodwater dissolved O2 content. During a 10-day flooding period, trees in floodwater with 15 ppm dissolved O2 content, and given exogenous ethylene, developed extensive stem lenticel hypertrophy, whereas no hypertrophy developed on stems of trees receiving no exogenous ethylene and maintained in floodwater with 15 ppm O2. These data suggest that ethylene plays a role in promoting stem lenticel hypertrophy in flooded mango trees.
MITIGATION OF HEAT STRESS EFFECTS ON POTATO GROWTH BY CALCIUM AND NITROGEN APPLICATION DURING STRESS
Authors: Tawfik Ahmed A. , Palta Jiwan P.
Published: February 2019

The optimum temperature regime for Solanum tuberosum cv. Russet Burbank is usually 20/15°C day/night. We studied the impact of heat stress (30/25°C, day/night) on the growth of this heat sensitive cultivar under controlled conditions (UW-Biotron). Plants were grown in sandy-loam soil which tested at 1500 Kg/ha Ca. Plants were at the maximum temperature for 6h during the middle of the day with a photoperiod of 14 hrs. All pots received identical amounts of total N (rate: 225 Kg N ha1.). The treatments were: (1) NSN: non-split N (N application 1/2 emergence, 1/2 two wks later): (2) SPN: split-N (1/2 emergence 1/6 at 2, 5 and 8 wks later); (3) SPN+Ca: Split-N+Ca (Ca at 2, 5 and 8 wks after emergence, total Ca from CaNO3 was 113 Kg ha1). Total leaf FWT and DWT was significantly reduced in NS treatment by heat stress at 13 wks as compared to optimum conditions. However, this was not reduced in SPN and SPN+Ca. Under heat stress: (a) SPN + Ca gave the highest leaf FWT and DWT, stomatal conductance, transpiration rate, and leaflet tissue Ca content; (b) Young expanding leaflets gave higher growth rate with SPN and SPN + Ca than NSN; (c) Ca content of mature leaflet decreased progressively in both NSN and SPN but not in SPN + Ca. Our results show that application of Ca and N during heat stress can mitigate stress effects and that maintenance of a certain level of calcium in leaf tissue is important under heat stress.
EFFECTS OF PHOTOPERIOD ON ALLIUM CEPA SEEDLINGS
Authors: Randle William , Lindstrom Orville , Warnock Daniel
Published: February 2019

The onion crop in Georgia is often damaged by suboptimal winter temperatures. Proper acclimation of seedlings is a way of limiting freeze damage. Because photoperiod is among the factors involved in plant acclimation, the effects of photoperiod on the acclimation of short-day Allium cepa seedlings was investigated. A single short-day cultivar, 'Granex 33', was greenhouse grown under an eleven hour photoperiod. After ten weeks of growth, four photoperiod treatments (8, 11, 14, and 24 hrs.) were administered during a two week hardening period at 3* C. Plants were then frozen in an ethylene glycol bath. Degree of acclimation was determined based on regrowth and visual observation. Acclimation of seedlings was completely inhibited by the 24 hour photoperiod. Varying degrees of acclimation were achieved with the other photoperiod treatments.
RESPONSE OF DATE PALM (PHOENIX DACTYLIFERA I.) SEEDLINGS TO SODIUM CHLORIDE IN IRRIGATION WATER
Authors: Aljuburi Hameed Jasim
Published: February 2019

The study was carried out at the Experimental Station of Agric. Sci. College at Al-oha region. Eight hundred seedlings (7 months old) were chosen for each following cultivars, Lulu, Boman, Barhee and Khalas. The seedings for each cultivars were irrigated weekly with 0, 6, 12, 18 g I.-1 Nacl solution.

The results revealed fresh weight of stems, roots and number of leaves/plant of Lulul, Barhee and Khalas cultivars progressively reduced with increasing Nacl concentration in irrigation water, while dry matter percentage of stems and roots increased and increasing salinity in irrigation water. The results also declared that the seedlings of four date palm cultivars has similar behavior, when exposed to high Nacl concentration in irrigation water during long term.
QUANTITATIVE MEASUREMENT OF CLUSTER COMPACTNESS IN SEVERAL TABLE GRAPE CULTIVARS.
Authors: Zabadal Thomas J. , Dittmer Thomas W.
Published: February 2019

Cluster compactness can affect fruit quality by influencing pesticide spray penetration into clusters and by predisposing berries to cracking and subsequent decay. Compactness of clusters can be altered through gibberellic acid sprays, flower cluster thinning and pruning severity. Assessment of cluster compactness has often been performed using a visual rating system which may not provide adequate quantitative measurement. Evaluation of cluster compactness by insertion of wedges between randomly chosen pairs of berries on a cluster revealed a high correlation with a visual rating system and a more sensitive measure of cluster compactness than the visual rating system. Several pruning severity treatments were applied to table grape cultivars to determine their influence on cluster compactness. It was possible to measure statistically significant differences in cluster compactness among these treatment using this wedge measurement technique.
SUPERABSORBENT POLYMER-AMENDED MEDIA FOR CONTAINER-GROWN WOODY ORNAMENTAL CROPS
Authors: Dehgan B. , Almira F. C. , Yeager T. H.
Published: February 2019

Rooted cuttings of Photinia X fraseri and Podocarpus macrophyllus were grown in Metro-mix 500 amended with 0.0, 0.25, 0.50, 0.75, or 1.0% (w/w) Stockosorb 300, a K-based superabsorbent polymer. All 3-liter containers were irrigated with 500 ml of 100, 200, 300, or 400 ppm 20N-8.7P-16.72K Peters fertilizer solution once every 3, 6, 9, or 12 days, respectively. In comparison with the unamended media, P. X fraseri had equal or better growth (shoot and root fresh and dry weights, increased height, and branch and leaf numbers) with 3, 6, and 9 day irrigation in all but the 1 % amended medium. Growth of P. macrophyllus was not noticeably affected by the polymer amendment. This is not unexpected since P. X fraseri is a broad-leaf plant while P. macrophyllus is a slow growing, narrow-leaf conifer. Nitrogen, P, and K tissue levels for Photinia and Podocarpus decreased for the 12 day irrigation treatment regardless of amendment rate. Except for Fe, which was highest at nine day irrigation intervals, micronutrients remained more or less constant in both species. The amended media had a greater water holding capacity at termination of the project (144 and 192 days for Photinia and Podocarpus, respectively) than at the start. Thus, K-based superabsorbents may be used successfully to reduce irrigation frequency.
DESIGN AND TESTING OF A NURSERY BLOCK FOR WATER RUNOFF RESEARCH
Authors: Cole Janet C. , Dole John M. , Stamback Vicki L.
Published: February 2019

Water quality has become a significant issue in the nursery industry. Local testing of runoff contamination from nursery production is, however, of little value to other growers because of the variation in management practices and nursery layouts. Two nursery blocks have been designed and constructed to test runoff from production with sprinkler and drip irrigation systems in combination with constant liquid fertilization and controlled release fertilizers. Management practices using various combinations of irrigation systems with fertilizer application rates are being tested in a small area with reasonable control of inputs. Preliminary data has shown no difference in plant response to irrigation method, but runoff was significantly reduced with drip irrigation. Plant quality was better with controlled release fertilizer, which generally yielded less N and P contamination in runoff, than constant liquid fertilization except during extremely hot weather.
COMPARISON OF ALTERNATIVE IRRIGATION SYSTEMS FOR CONTAINER NURSERY STOCK PRODUCTION
Authors: Calkins James B. , Swanson Bert T. , Krueger Daniel G. , Lundquist Karin R.
Published: February 2019

A study was designed to ascertain the efficacy, water use efficiency, runoff potential, and cost effectiveness of four container irrigation systems: overhead sprinkler irrigation, in-line trickle irrigation, capillary mat with leaky hose, and sub-irrigation. Results were species dependent. Plant growth was best under capillary mat and trickle irrigation treatments, however, differences in plant growth and performance between irrigation treatments were minimal. Differences in water use, however, were quite significant. Overhead irrigation was inefficient regarding water use while capillary mat and trickle systems used much lower volumes of water. Conservative irrigation systems which maintain acceptable plant growth using less water and reduce runoff from container production areas can clearly benefit growers by reducing production and environmental costs.
THE CACTACEAE FAMILY — A POTENTIAL CANDIDATE FOR THE EXOTIC FRUIT INDUSTRY
Authors: Mizrahi Yosef , Nerd Avinoam
Published: February 2019

Numerous species of cacti were introduced in an attempt to diversify the types of fruit trees cultivable under the conditions of the Israeli Negev Desert. The new species were tested in five introduction orchards varying in type of soil, climate and irrigation water. Fruits of the Hylocereus genus, which must be grown on a trellis system under netting, were found to be of an attractive shape, color, appearance and taste. Cereus peruvianus, which grows outdoors, produced beautiful tasty fruits which varied in color from yellow to deep red. Fruits of these species are of the nonclimacteric type and are capable of withstanding long-distance transportation. Some have to be cross-pollinated while others can be self-pollinated. They flower twice or three times a year, bearing fruits from June to November. These types are characterized by a CAM photosynthetic pathway, pointing to high water use efficiency.
A CONTAINERIZED METHOD OF SCREENING FOR RESISTANCE TO ROOT ROT CAUSED BY PHYMATOTRICHUM OMNIVORUM
Authors: Nesbitt Monte L. , Storey J.B. , Lyda S.D. , Grauke L.J.
Published: February 2019

Phymatotrichum Root Rot, caused by Phymatotrichum omnivorum (Shear) Duggar, imposes severe losses upon dicotyledonous horticultural crops in the southwestern United States and northern Mexico. Rootstock resistance could benefit pecan (Carya illinoensis) production in affected growing areas; however, erratic growth habit of this pathogen and site variability prevents effective field screening. We have developed a containerized screening method for horticultural crops, using a commercial soilless growing medium. In sterile cultures, 2.5 × 60 cm glass tubes containing Metro Mix 500 yielded more grams of P. omnivorum sclerotia than cultures grown in Houston Black Clay, a traditional medium for cotton research. Preliminary screening with Okra (Abelmoschus esculentus) in non-sterile Metro-Mix 500 resulted in 75% mortality of inoculated plants in 30-35 days. Preliminary screening with 12-week-old, open-pollinated `Apache' and `Moore' pecan rootstocks has resulted in 25% mortality of inoculated plants in 150 days. Pecan seedlings with visible taproot infection appear to delay mortality by adventitious root formation.
THE IMPACT OF ROSE BLOOM DISEASE (Exobasidium oxycocci) ON THE PHOTOSYNTHETIC BIOLOGY OF CRANBERRY
Authors: Cameron J. Scott , Bristow Peter R.
Published: February 2019

Gas exchange measurements were made on healthy and rose bloom infected branches of cranberry on 31 May 1991 during the middle of the sporing period. CO2 assimilation rates of infected branches were reduced 89% on a leaf area basis and 95% on a dry weight basis compared to healthy tissue. Stomatal conductance was 12× higher in infected tissue, while mesophyll conductance was reduced by 92%. Transpiration was 4× higher in diseased tissue reducing water use efficiency by 96%.

Total chlorophyll content of diseased tissue was 81% less than that of healthy tissue but chlorophyll a/b was unchanged. Fourth derivative profiles of chlorophyll action spectra were altered in diseased tissue. Rose bloom leaves were found to lack stomata and have no discernable mesophyll layer.
TRANSPORTATION ROUTES FOR LATIN AMERICAN PRODUCE IMPORTS INTO THE UNITED STATES
Authors: Picha David H. , Hinson Roger A.
Published: February 2019

The origin and distribution of counter-seasonal fresh fruit and vegetable imports from Latin America into the U.S. was evaluated. Infrastructure comparisons were made among various U.S. ports of entry capable of receiving perishables. Economic comparisons were made utilizing different transportation routes. Market boundary analyses indicated significant cost savings would result from changing existing transportation routes to certain final U.S. destinations. Currently the port of Philadelphia receives the majority of South American fruit which is mostly shipped break bulk or palletized. South Florida ports (Miami and Port Everglades) receive the majority of Central American and Caribbean fruits and vegetables which are mostly shipped containerized. Interest exists among Latin American exporters to diversify their U.S. ports of entry in order to avoid distribution bottlenecks. Future trade routes will likely see an increased utilization of more economical U.S. Gulf of Mexico ports.
STONY HARD GENE OF PEACH ALTERS ETHYLENE BIOSYNTHESIS, RESPIRATION, AND OTHER RIPENING-RELATED CHARACTERISTICS
Authors: Goffreda Joseph C.
Published: February 2019

The stony hard gene in peach is a recessive gene which increases fruit firmness and shelf-life. Five progenies segregating for the stony hard trait were scored for several ripening-related characteristics. Fruit from stony hard segregants produced little or no ethylene, had lower respiration rates, and tended to ripen later than `normal' fruit. Stony hard fruit also had a lower percentage red overcolor in three of the five progenies. Stony hard fruit, harvested when firm-ripe, maintained their firmness after five days storage at 20°C. Firmness of stony hard fruit decreased significantly if the fruit were sprayed with ethephon (2-chloroethylphosphonic acid) at 250 ppm prior to storage. Fruit firmness of `normal' freestone or clingstone varieties was not significantly affected by the application of ethephon. The conversion of ethylene precursors to ethylene in stony hard fruit will also be discussed.
SEASONAL VARIATION IN LOW-TEMPERATURE TOLERANCE OF FRUIT-BUDS OF VACCINIUM ANGUSTIFOLIUM.
Authors: Cappiello Paul E.
Published: February 2019

Lowbush blueberry (Vaccinium angustifolium) is a major fruit crop in costal, Northern New England and Atlantic Canada. One of the factors affecting production is low temperature damage of flower primordia. In addition to mid-winter damage, much of the damage occurs in spring due to late frosts. A study was designed to examine the seasonal variation in the LT50 of fruit buds and to determine the location of the tissue damage.

Field-collected stems were exposed to controlled temperature drops and examined for damage. Three types of damage were identified; destruction of flower primordia, browning of vascular tissue within the fruit-bud, and browning of stem tissue at the base of the bud. The seasonal variation of the occurrence of this damage will be discussed.
PHYSICAL AND BIOCHEMICAL STUDIES OF DORMANCY IN APPLE BUDS
Authors: Liu Dehua , Faust Miklos , Norman Helen A. , Millard Merle , Stutte Garry W.
Published: February 2019

Membrane lipids and cellular water states were studied in endodormant and paradormant apple buds. Paradormancy was overcome by thidiazuron while endodormant buds were forced to break after a certain period of chilling. Nuclear magnetic resonance imaging was used to determine water states in buds of different stages of dormancy. In endodormant buds, the changes in water states from a more tightly-bound to a more free form were correlated with changes in membrane fatty acid composition. The ratio of saturated/unsaturated fatty acids decreased with chilling, especially in C18:l/C18:3 molecular species of phosphatidylcholine and phosphatidylethanolamine. Bud lipase activity, which was assayed by in vitro hydrolysis of triglycerides, showed an abrupt increase after chilling treatments.
NITROGEN, POTASSIUM, AND CARBOHYDRATE PARTITIONING IN FIELD-GROWN GRAPEVINES OVER A TWO-YEAR PERIOD
Authors: Williams Larry E.
Published: February 2019

Entire Thompson Seedless grapevines (to include the root system) were harvested at regular intervals over a two year period. Dry matter, soluble carbohydrates, N and K were quantified on an individual organ basis for each date. The pattern of dry matter partitioning to the roots and trunk were similar from one year to the next. Decreases in dry weight in the roots and trunk were accompained by decreases in soluble carbohydrates. The concentration of K in the roots remained almost constant over the two year period while that of N fluctuated from less than 1% (dry wt basis) to more than 2.5% depending on the time of the year. The dynamics of N and K within the trunk on a concentration or content (g vine-1) basis were similar to one another. N and K were remobilized from the trunk early in the growing while only N was remobilized from the root system. Remobilization of N from the roots took place from berry set until harvest.
SAP NITRATE TESTING FOR IMPROVED NITROGEN MANAGEMENT ON POTATOES
Authors: Vitosh Maurice L. , Silva George H. , Leep Richard D. , Douches David S.
Published: February 2019

A procedure for rapid determination of nitrate in the fresh petiole sap using an ion specific electrode was developed. A highly significant correlation (R2-0.92) was obtained between the nitrate measured by the sap test and the conventional oven-dried tissue method.

The effects of five nitrogen(N) rates ranging from 0 to 268 kg ha-1, and five dates of sampling dates beginning at tuber initiation, on the sap nitrate concentration were investigated. The nitrate level increased in proportion to N fertilizer rate. The nitrate level was generally higher at tuber initiation and decreased as the season progressed. The rate of decrease was related to the N supply in the soil. At N rates of 0 and 67 Kg ha-1, the average weekly decrease in the nitrate level was greater than 100 ppm. Based on yield response, the nitrate levels were partitioned as deficient adequate and excessive, and a critical nutrient range was established. The sap test offers a tactical approach for corrective in-season fertilization and a means to increase the efficiency of both fertilizer and available soil N.
THE CAUSE AND CURE OF LEAF CRISPING IN CUT ROSE STEMS
Authors: Markhart Albert H. , Harper Mark
Published: February 2019

Roses are grown in Minnesota in the winter in closed greenhouses with the aid of HID lamps, and carbon dioxide enrichment. Although productivity is good, consumers often complain of a rapid dehydration or crisping of the leaves. Through a series of experiments using controlled environment chambers and known vase solutions we have determined that the crisping is due to the deposition of high levels of sucrose in the leaf cell walls due to transpiration from the leaves. The sucrose dehydrates the cell protoplast causing cell collapse and tissue death. Crisping is reduced by lowering the sucrose in the vase solution or reducing transpiration from the leaves. Abscisic acid added to the vase solution effectively reduced transpiration and crisping.
PROTEA LEAF BLACKENING
Authors: Dai Jinqwei , Paull R. E.
Published: February 2019

Leaf blackening in Protea neriifolia R. Br. is influenced by sink demand and nectar production. Maximum nectar production occurred when the flower was in the cylindrical shape. C14-sucrose applied to a postharvest flower stem leaf moved preferentially into the nectar (65%). Darkness increased the rate of leaf blackening. Covering an individual leaf on a postharvest flower stem with aluminum foil lead to leaf blackening in 3 days while removing the inflorescence or girdling the stem just below the inflorescence prevented this leaf blackening. Girdling the stem around a leaf base and covering this leaf with foil resulted in leaf blackening in 5 days, but removal of the inflorescence influence did not prevent blackening. Sucrose 2.5% (w/v) in the vase solution prevented leaf blackening in both girdled and non-girdled leaves covered with foil. Polyphenol oxidase apparently plays an important role in protea leaf blackening. Leucospermum, another genera in the family of Proteaceae, did not show any PPO activity and did not blacken in the dark, while high PPO activity was detected in leaf extract of P. neriifolia.
INFLORESCENCE SINK DEMAND AND LEAF BLACKENING IN PROTEA NERIIFOLIA.
Authors: McConchie Robyn , Lang N.Suzanne
Published: February 2019

A major postharvest problem of Protea neriifolia is premature leaf blackening. Carbohydrate stress, due to floral sink demand, may lead to cellular disorganization and leaf blackening. Leaf blackening, nonstructural carbohydrates, ethylene, carbon exchange rates, stomatal conductance and lipid peroxidation were measured on leaves of vegetative and floral stems preharvest, and during a 7 day dark postharvest period. Postharvest treatments were: 0 or 0.5% sucrose in the vase solution, 20% sucrose pulse, or floral decapitation. Leaf blackening was significantly reduced in vegetative stems and floral stems in the 20% pulse treatment, in comparison to all other treatments. Ethylene production and lipid peroxidation were not associated with leaf blackening in any treatment and leaf respiration rates declined for all treatments over time. The magnitude and rate of leaf blackening was inversely related to leaf starch concentrations, with greatest carbohydrate depletion occurring within 24 h of harvest (by 75-85%). Leaf starch from the 20% pulse treatment increased by 300%, in contrast to declining starch concentrations in all other treatments. The data suggest that the flowerhead functions as the major sink for carbohydrate depletion leading to subsequent leaf blackening.
PROTOPLAST REGENERATION OF IPOMOEA CORDATOTRILOBA, A SPECIES CLOSELY RELATED TO SWEETPOTATO.
Authors: Kobayashi Ruth S. , Bouwkamp John C. , Sinden Stephen L.
Published: February 2019

The use of wild Ipomoea species in sweetpotato improvement may be facilitated by the use of in vitro techniques such as somatic hybridization. Plant regeneration from callus cultures is essential to the successful application of these in vitro techniques. This is the first report of plant regeneration of I. cordatotriloba from protoplast derived calli. Protoplasts isolated from petiole and stem tissues of in vitro grown I. cordatotriloba were initially cultured on KM8p media. All calli cultured regenerated roots after 1 month on regeneration media. Approximately 13% and 19%, respectively, of the calli cultured regenerated shoots after 2 months on media containing 10 and 100 uM parachlorophenoxy isobutyric acid (PCIB). Regenerated shoots developed into whole plants when transferred to MS media without hormones. The regenerated plants closely resembled the parent's morphology.
HYPOCOTYL ORIENTATION AND HORMONE INFLUENCE IN VITRO REGENERATION OF ROOT AND SHOOT OF CAULIFLOWER (BRASSICA OLERACEA L. VAR. BOTRYTIS) `PUAKEA'.
Authors: Sukamto L. Agus
Published: February 2019

Hypocotyl sections of cauliflower were cultured in horizontal, upright or inverted positions on Murashige and Skoog medium with different concentrations of 6-benzylaminopurine (BAP) and α-naphthylacetic acid (NAA). Inverted position gave the highest differentiated score and greatest fresh weight of the two month-old tissues, followed by upright and horizontal positions respectively. Combination BAP and NAA caused synergistic effect on tissues. The best treatment for getting callus was combination of 5 mg/liter BAP, 2 mg/liter NAA and upright position, whereas for getting tissue differentiation was combination of 5 mg/liter BAP, 1 mg/liter NAA and inverted position.
TRANSIENT GENE EXPRESSION IN SPINACH CALLUS TRANSFORMED WITH AGROBACTERIUM TUMEFACIENS
Authors: Al-Khayri J.M. , Huang F.H. , Morelock T.E. , Zhang H.T.
Published: February 2019

The objective of this study was to determine the efficacy of Agrobacterium tumefaciens in transforming spinach (Spinacia oleracea L.) callus. Callus was induced from leaf disks of `Baker' on Murashige and Skoog (MS) medium supplemented with 2 mg L-1 kinetin and 0.5 mg L-1 2,4-D. Callus was cut into 2-mm pieces, and 0.5 g of callus was placed in each 250-ml flask which contained 20 ml of MS liquid medium. The suspension cultures were inoculated with 100 μl of an overnight culture of A. tumefaciens harboring pMON 9749 (provided by S. Rogers, Monsanto Co., St. Louis), a plasmid cointegrated with kanamycin resistance and β -glucuronidase (GUS) genes. After coculturing for 2 days at 22C with shaking at 100 rpm, the medium was replaced with selection medium containing (in μg/ml) 75 kanamycin, 100 cefotaxime, and 200 carbenicillin and maintained for 3 weeks. Transient expression of GUS gene in transformed cells was detected with X-glu assay. This method resulted in a high level of transformation and provides the first report of transformation in spinach. This study was funded by a grant (92-B-32) from the Arkansas Science & Technology Authority.
EVALUATION OF MULCHES IN FIELD-GROWN FRESH-MARKET TOMATOES
Authors: Abdul-Baki Aref A. , Teasdale John R.
Published: February 2019

Hairy vetch, subterranean clover, polyethylene black mulch (PBM), and Horto paper were evaluated in field-grown fresh market production of tomatoes (Lycopersicon esculentum Mill), cv `Sunny'. Plant mulches were grown in beds in the fall, mowed immediately before planting, and the tomato seedlings were planted without tillage in a low input system. Yields (t.ha-1) for hairy vetch, subterranean clover, PBM, Horto paper, and no mulch were 72.1, 46.6, 59.9, 54.0, and 29.8, respectively. Although the tomato plants grown under plant mulches received 50% of the recommended fertilizer application, they produced more vigorous plants than those in other treatments. Plant mulches were effective in controlling growth of weeds and infestation by Colorado potato beetle.
PRODUCTION OF DWARF RAPID-CYCLING BRASSICA UNDER OPTIMIZING ENVIRONMENTAL CONDITIONS
Authors: Frick J. , Mitchell C.A.
Published: February 2019

Due to its short time to flower (14-18 days) and rapid maturation cycle (50-55 days), dwarf rapid-cycling brassica (Brassica napus) is under consideration as a candidate oilseed crop for NASA's Controlled Ecological Life Support Systems program. Recent work has focused on defining a set of optimum environmental conditions which permit increased crop yield in terms of g·m-2d-1 of edible biomass. A wide range of environmental variables have been considered including lamp type, CO2 level, nutrient solution pH, and planting density. In addition, nitrogen nutrition regimes have been manipulated with respect to nitrogen concentration (2 to 30 mM), source (NH4+ and/or NO3-), and time of stepwise changes in nitrogen level (day 14 to 28). The highest seed oil content (42% DW basis) has been found under limiting nitrogen levels (2 mM). However, the low nitrogen inhibits overall seed production potential. Different cultural techniques also have been compared, including solid-substrate, passive wicking hydroponics versus liquid culture systems. Trials are underway to assess crop growth and development under the “best set” scenario of environmental conditions. At present, the highest seed yield (10.6 g·m-2d-1) has been obtained using solid-substrate hydroponic systems under a combination of metal halide and high-pressure sodium lamps. Constant CO2 enrichment to 1000 μmol·mol-1 did not increase crop yield rate.

Research supported in part by NASA grant NAGW - 2329.
GROWTH RESPONSE OF SELECTED VEGETABLES TO GUAR RESIDUES
Authors: Reid-Goldman Debbie , Daniello Frank , Ed Clark L.
Published: February 2019

Greenhouse and field studies indicate that guar (Cyamopsis Tetragonoloba (L.) Taub.) residues stimulate growth of three different vegetable species: spinach (Spinacia oleracea L. variety “Polka” watermelon (Citrullus vulgaris Schrad. variety “All Sweet”, and cucumber (Cucumis sativus L. variety “Poinsett 76”. Growth response was greater than that contributed by nitrogen from guar residue suggesting that an allelochemical may be responsible. Significant differences were found in growth response of spinach to separated components of the guar plant. No significant differences were found between partially decomposed and non-decomposed guar residue. A stimulated growth response was observed in two media: a pasteurized mineral soil and a sterilized sand.
EFFECT OF ETHYLENE AND ABSCISIC ACID ON THE FORMATION OF PITHINESS IN CELERY (APIUM GRAVEOLENS)
Authors: Mangrich Mary E. , Saltveit Mikal E.
Published: February 2019

Ethylene induces arenchyma formation in corn roots and other plant tissues, and abscisic acid (ABA) induces arenchyma in celery petioles. Pithiness (i.e., arenchyma) in celery can be measured as a decrease in density. Density was calculated for two cm long petiole segments by dividing their weight by their volume as calculated from the weight of water displaced upon immersion. The relationship between density (g/ml) and subjective pithiness rating (1 = none, 9 = severe) was linear (r2 = 0.87). Petiole segments exposed to 0 to 200 ppm ethylene in air at 5C for two weeks did not exhibit any significant differences (p = 0.05) in density among the treatments. Entire petioles were treated with 0, 1, 10, and 100 μM ABA in water for 96 h at 25C. The petioles were cut into thirds and the center 2 cm from each portion was excised and the density measured. Although density decreased in the top to the bottom portions over all ABA conc, the differences were not significant. Density was significantly reduced in segments excised from the bottom and middle of petioles treated with 10 and 100 μM ABA, compared to 0 and 1 μM ABA. There also was a decrease in density with ABA conc in the top portion, but the decrease was only significant for the 100 μM ABA conc.
STABILITY ANALYSIS OF YIELD AND THE COMPONENTS OF YIELD AMONG COFFEE GENOTYPES.
Authors: Upreti Gopi , Bittenbender Harry C.
Published: February 2019

Thirteen coffee genotypes (Coffee arabica) were evaluated for yield stability in fourteen environments within Hawaii. The yield components (fruiting nodes, fruits/node, and fruit size) were also evaluated for stability in four environments. Genotype yield and component were regressed against environmental mean yield and yield component to determine the stability of yield and the components of yield.

Cultivars with means above the grand mean, regression coefficients ≤ 1, and the coefficients of linear determination ≥ 50% were considered to be superior and have phenotypic stability. Stable and superior genotypes are less sensitive to environmental changes and are more adapted to favorable and unfavorable conditions than unstable genotypes.

`Catuai' was stable for both yield and the components of yield (fruiting nodes, and fruits/node) which directly contribute to the yield. The genotype `SL 28' was unstable but highly responsive to favorable environments for yield as well as yield components. Selection for the stability of yield should be considered in coffee breeding programmes to develop genotypes adapted to diverse environmental conditions in Hawaii.
DIVERSITY OF NEPHELIUM SPECIES IN BRUNEI DARUSSALAM
Authors: Serudin HJ , Tinggal HJ
Published: February 2019

Nephelium spp. are abundant in Brunei Darussalam. Their trees bear fruits of various sizes and colors and are highly ornate, but only a few are known and cultivated for their edible fruit. The best known is the rambutan (Nephelium lappaceum Linn) which is extensively cultivated in parts of SE Asia & N. Australia. The commercial rambutan cultivars evolved from years of natural & artificial selection, resulting in wide variations of fruit sizes, colors & tastes. Malaysia, Thailand, Indonesia, Philippines, Singapore and Brunei each have their own favorite cultivars & clones. One of the most formidable research challenges of rambutan is to extend the shelf life of the fruit. The soft spinterns and fragile skin deteriorates rapidly, becoming dull brownish & dry within four days of harvest. The white translucent flesh also rapidly becomes soft and watery. A potential research direction is to breed for `spintern-less' rambutan. This strategy may be feasible within the genetic resources of Nephelium in Brunei Darussalam where there are spintern-less types. The diversity of Nephelium species found in Brunei Darussalam will be elaborated on.