bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECTS OF N FERTILITY, PLANT DENSITY AND CULTIVAR ON YIELD OF DILL
Authors: Bandele Owusu , Wolff Xenia , Belvitt Byron , Egbe Justin
Published: February 2019

Two experiments were conducted in 1988 and 1990 to determine the effects of planting density, N fertilizer rate, and cultivar on fresh yield of dill. A split plot design was used in the first experiment in which planting density (one versus two rows per bed) was the main plot treatment and N rate (0, 56, 112 kg/ha) was the subplot treatment. A European cultivar, `Crown,' was used in the first experiment in 1988 while `Long Island Mammoth' was planted in 1990, N was applied in split applications while both K2 O and P2 O5 were preplant incorporated at the rate of 134 kg/ha. Planting was done on bedded rows approximately 66 cm wide and 15 cm high. N fertilizer application did not affect yield in 1988. Leaf, stem, flower, and total yields were greater for the high density planting. The second experiment evaluated yield of four cultivars (`Tetra,' `Bouquet.' `Long Island Mammoth,' and `Crown') using a randomized complete block design. `Long Island Mammoth' and `Tetra' produced greater leaf and total fresh weight while `Long Island Mammoth' and `Bouquet' produced greater flower fresh weight.
PHOTOSYNTHESIS, RESPIRATION, AND CARBON COST OF DEVELOPING RABBITEYE BLUEBERRY FRUIT
Authors: Birkhold Keith , Darnell Rebecca , Koch Karen
Published: February 2019

Carbon exchange and content of blueberry (Vaccinium ashei) fruit were measured from anthesis through fruit ripening in order to determine the amount of imported carbon required for fruit development. Net photosynthesis occurred in blueberry fruit from petal fall through color break. During this time, gross photosynthesis of fruit decreased from 30.1 μmol CO2·g fw-1·hr-1 to 4.8 μmol CO2·g fw-1·hr-1, and dark respiration decreased from 14.3 μmol CO2·g fw-1·hr-1 to 4.6 μmol CO2·g fw-1·hr-1. After color break, the photosynthetic rate fell to zero, and the respiration rate increased to 8.0 μmol CO2·g fw-1·hr-1, before decreasing. Preliminary data suggest that fruit photosynthesis contributes 11% of the total carbon required (dry weight gain + respiratory loss) during fruit development however, it supplies 50% of the total carbon required during the first 5 days after petal fall. This contribution of carbon from fruit photosynthesis may be critical in initial fruit development since the current season's vegetative growth is not yet providing carbohydrates.
PHOTOSYNTHETIC INHIBITION IN STRAWBERRY GROWN UNDER TWICE AMBIENT CO2
Authors: Moon John W.
Published: February 2019

`Midway' and `Raritan' strawberry cultivars were grown for six weeks under ambient (350) or twice ambient (700 μmol mol-1) CO2 Photosynthetic inhibition (40-50%) was observed in both cultivars as indicated by reductions (P < 0.001) in CO2 assimilation, carboxylation efficiency, stomatal conductance, and apparent quantum yield. Growth under high CO2 did not affect Rubisco activity in either cultivar, whereas Rubisco activation state (%) was reduced (72.9 to 67.6) in `Midway' and increased (70.8 to 83.3) in `Raritan' compared to ambient CO2 grown plants. Soluble and Rubisco protein decreased 10-15% in `Midway' and 40-45% in `Raritan' when grown under high CO2 Thus, `Raritan' reduced the amount of protein partitioned into photosynthetic enzymes under conditions of photosynthetic inhibition, whereas `Midway' experiences Rubisco deactivation. The reduction in Rubisco protein appears to be under the regulation of chloroplast genes.
UTILIZATION OF POSTHARVEST GIBBERELLIC ACID SPRAYS TO REDUCE HAND THINNING IN `PATTERSON' APRICOT
Authors: Southwick Stephen M. , Yeager James T.
Published: February 2019

Heavy fruit set of apricot (Prunus armeniaca) cultivars grown in California often require hand thinning to insure that adequate fruit size is obtained. Alternatives to costly hand thinning would be welcome. GA treatments made during flower bud initiation/differentiation have been previously shown to inhibit the development of floral and vegetative buds in a number of different tree fruit species. The effects of post-harvest limb and whole tree aqueous gibberellic acid (GA) sprays on flower and fruit production were investigated over a 3 year period in `Patterson' apricot. Limb treatments indicated the potential for utilizing postharvest GA sprays to reduce the number of flowers produced in the following season. Harvest fruit size (June 1989) was increased by a 100 mg·liter-1 GA whole tree spray applied 7 July 1988 when compared to non-thinned and hand thinned trees. Yield per tree was reduced by that GA spray, but not enough to show statistical differences. No abnormal tree growth responses have been observed in GA-sprayed trees to date. These results and those from the 1989 and 1990 growing seasons will be presented in effort to identify a role for whole tree postharvest GA sprays in a chemical thinning program suitable for commercial apricots.
FUNCTIONAL MALE STERILITY IN EGGPLANT: INHERITANCE AND LINKAGE TO THE PURPLE FRUIT COLOR GENE
Authors: Phatak Sharad C. , Liu Jinsheng , Jaworski Casimir A. , Sultanbawa A. Fazal
Published: February 2019

The functional male sterile (fms) eggplant (Solanum melohgena L.) germplasm UGA 1-MS was crossed with two cultivars, `UGA 18 White' and `Florida Market' with normal anthers to derive F1, F2, and BC populations. Functional male sterility (fms) was governed by a single recessive allele. The gene symbol fms is proposed for this male sterile characteristic. The functional male sterility gene was linked to purple fruit color at the X/x locus. Our observations also revealed that the purple or violet color ware not only on the fruit peel, but also on the anthers and leaf buds if the eggplant fruit was purple or violet. In the transmission of parents and progenies of the cross of UGA 1-MS × `UGA 18 White', the purple line on the anther and leaf bud purple color ware tightly associated with fruit purple color. Thus, it is assumed that the allele X controls not only purple fruit, but also the expression of the purple line on the anther and purple leaf bud.
BRANCH POSITION, DEFOLIATION, DISBUDDING AND GIRDLING ON FLORAL INITIATION, FLOWERING AND FRUIT SET OF OLIVE.
Authors: Martinez-Díaz Gerardo , Navarro-Ainza J.A. Crisitóbal , Grijalva-Contreras Raúl
Published: February 2019

Flower density, number of flowers per inflorescence and fruit set in `Mission' `Barouni' and `Ascolano' olive trees were related to cardinal orientation of branches: branches located at W and N showed higher values than S and E branches. Observations about floral development indicated that floral initiation of cv Mission ocurred earlier on N and W branches (Feb. 26th to March 7th) than on E and S ones (March 7th to April 26th). Defoliation on January 12th decreased number of inflorescences per branch, but such effect. was counteracted if buds up or below the defoliated region were eliminated. Girdling decreased the action of desbudding, mainly if desbudding was performed above the defoliated region.
THE EFFECTS OF BAGGING ON FRUIT SET AND FRUIT CHARACTERISTICS OF DATE PALM KHASTAWI CV. (PHOENIX DACTYLIFERA).
Authors: Mawlood Essam A. , Hamood H.H , Salah E.S.
Published: February 2019

This experiment was conducted to study the effects of bagging on fruit set, fruit characteristics and yield of Khastawi Date Palm CV. Two different types of bags were used: cloth and paper. The spadices were covered immediately at two different times during the first season; one month and the second continued until harvest time. Since positive results were obtained during the season, two extra bagging treatments were added in the second season (2 and 3 months). Unbagged spadices were used as control for both seasons. The results indicated that there were no significant differences between the two types of bags. Moreover, bagging for either two or three months produced positive results in fruit set improvement and yield.
EFFECTS OF PREHARVEST IRRIGATION CUTOFF DURATION ON FRENCH PRUNE TREE PERFORMANCE
Authors: Sibbett G. S. , Goldhamer D. , Southwick S. , Phene R.C. , Yeager J. , Katayama D.
Published: February 2019

Variable lengths of water deprivation immediately prior to harvest were imposed on mature French prune trees for four consecutive years. Irrigation cutoff durations were about 45, 37, 30, 22, 17 and 12 days prior to harvest during 1986-89.

Predawn leaf water potential best reflected water deprivation length and reached minimum values of about -1.5 MPa with the most severe cutoff. Magnitude of peak stomatal conductance was reduced and occurred earlier in the day with longer cutoff regimes.

Rate and time-course development of preharvest fruit drop was variable from year-to-year, but there were no significant differences in total drop between cutoff treatments. Only in the fourth year, following three years of no difference were tree fruit load and yield significantly reduced but then only with the most severe cutoff. Soluble solids were higher and drying ratios lower with the longer cutoffs. Fruit size was significantly reduced in the third year of the experiment. Trunk circumferences were significantly lower only with trees subjected to the longer cutoff regimes.
IMPACT OF SALINITY ON IRRIGATED MACADAMIA PRODUCTION
Authors: Bittenbender H.C. , Hue N.V.
Published: February 2019

Many areas in Hawaii with potential for growing macadamia lack sufficient rainfall. Ground water in these areas is generally brackish due to sea water intrusion. An experiment was started in 1984 to determine the response of young macadamia trees cv. `Kau' (HAES 344) Macadamia integrifolia to salinity under field irrigated conditions. Treatments were rain only, freshwater, 500 and 1200 ppm salt as diluted sea water to simulate the ground water conditions.

Until mid 1989 trees were irrigated twice weekly to supply 100% ET (evapotranspiration) of the previous week based on a class A pan. No differences were detected among treatments on yield, trunk diameter, soil and tissue nutrient composition except trees in the rain only treatment less yield and trunk growth. Irrigation treatments were modified in mid 1989 to rain only, and twice weekly fresh water, 1200 and 2400 ppm salt at 50 and 75%. ET. Effect on yield, trunk diameter, soil and tissue nutrient composition in the 1989-90 season will be reported.
ROOT TURNOVER: METHODS OF ANALYSIS
Authors: Eissenstat David
Published: February 2019

Root turnover has been determined primarily in ecosystem studies with perennial vegetation since it is a key for understanding primary production and nutrient cycling. These topics have become of interest to agriculturalists as well. Apart from ecosystem-level questions, there has been limited study of the environmental factors that influence root death. Many techniques have been devised to estimate root turnover, each with its own set of limitations. In forest ecosystems, one of the most popular methods of estimating root production turnover is sequential biomass sampling. However, this method fails to account for the simultaneous production and decomposition of roots during active periods of net biomass increase. A second method is a mesh-bag technique, which estimates root production/turnover from the amount of new roots that grow into a mesh bag. A method that uses radiocarbon is one of the most accurate, since estimates of root turnover include losses by exudation, cortical cell sloughing, as well as root loss. A fourth method of estimating root turnover involves tracking the roots visible behind transparent glass or plastic. Ultimately, the choice of method depends to a large extent on the type of plants used in the investigation and resources available for study.
BREEDING OF RHIPSALIDOPSIS AND SCHLUMBERGERA
Authors: Boyle Thomas H.
Published: February 2019

Rhipsalidopsis (Easter cactus) and Schlumbergera (Thanksgiving and Christmas cactus) are two genera of epiphytic cacti endemic to southeastern Brazil. Rhipsalidopsis is comprised of two species (R. gaertneri and R. rosea) and Schlumbergera contains five species (S. opuntioides, S. obtusangula, S. orssichiana, S. russelliana, and S. truncata). There is considerable potential for the improvement of commercial cultivars in both genera. Flower color and form, plant habit, postharvest performance, and the responsiveness to floral induction treatments are selection criteria used in breeding of Rhipsalidopsis. The selection criteria used in breeding of Schlumbergera are flower color and form, growth rate, phylloclade size and shape, plant habit, and the critical daylength for flowering. Inbreeding depression, self-incompatibility, and a long generation time (1.5 to 3 years) are impediments to breeding in both genera. Interspecific hybridization has been performed in Rhipsalidopsis and Schlumbergera, and significant phenotypic variation has been observed within interspecific hybrid populations.
ROOTSTOCK INFLUENCE ON FRUIT TREE ARCHITECTURE
Authors: Cummins James N.
Published: February 2019

Rootstock influence on tree architecture may be seen in a variety of expressions. Above ground effects include canopy volume and shape, crotch angles, branch display angles, relative distribution of long shoots and spurs, internode length, relative distribution of fruit buds and spurs, and trunk taper. Below the graft union, effects include relative distribution of fine vs. coarse roots, total root mass, and numbers, nature and distribution of burrknots. Many of these phenomena are indirect effects that stare from induction of fruiting by the rootstock, e.g., early fruit production induced by the rootstock will result in reduced canopy volume, reduced aboveground total mass, flatter branch display angles, and reduced root mass. The rootstock also plays a major role in the duration of shoot extension growth; by influencing the production of growth regulators in the shoot tip, the rootstock indirectly influences the inhibit ion of lateral buds and therefore the production of feathers.
USE OF ENVIRONMENTAL MANIPULATIONS IN SMALL FRUIT PRODUCTION
Authors: Pritts Marvin P.
Published: February 2019

Manipulating light, temperature, moisture, and nutrients to favor plant growth and productivity is an important component of horticulture. The technology required to achieve such manipulation ranges from inexpensive, basic practices to elaborate, costly approaches involving the latest engineering advances. For example, pruning and mulching are relatively low-tech methods for improving light interception and soil moisture status in small fruit plantings. At the opposite extreme are glass houses with supplemental lighting, CO2 enrichment, and nutrient film hydroponic systems Of greatest value to small fruit growers, however, is technology that ran be applied in field situations, such as the use of overhead irrigation for maintaining soil moisture status, frost protection, and evaporative cooling. One of the greatest challenges to small fruit growers and rcsearchers is integrating new technology into production systems. The introduction of a new technique for environmental modification usually has indirect effects on other aspects of management, which may require additional technology to compensate for adverse changes while maintaining the favorable change. In addition, unique macro- and microclimates demand and market opportunities, specific solutions, and the result is a dynamic, diverse collage of production systems used by growers throughout the world.
RELATIVE GROWTH RATE: THE TWO-PHASE CURVE
Authors: DeJong Theodore M.
Published: February 2019

The growth and development patterns of fruit have been studied for many years and it has become traditional to think of peaches as having a double sigmoid pattern with three main stages fruit growth. This concept is primarily based on analyses of fruit absolute growth rates An alternative approach is to express growth on a relative growth rate (RGR) basis which is simply the weight increase perg of fruit weight per day. This analysis applied to dry-weight peach fruit growth results in a two-phase curve that is known mathematically as a Gompertz function. During the first growth phase the RGR decreases logarithmically and during the second phase the RGR remains relatively stable. Expressing fruit growth on a RGR basis is advantageous for fruit growth carbon budget modelling because RGR is directly related to respiration rates and for physiological studies because most analyses for physiologically active substances are expressed on a weight basis. There is obviously not only one “right” way to express fruit growth but it may be instructive to use the RGR approach particularly when studying factors that may be associated with “sink” activity.
Influence of Gel Additives on Nitrate, Ammonium, and Water Retention and Tomato Growth in a Soilless Medium
Authors: Bres Wlodzimierz , Weston Leslie A.
Published: February 2019

Experiments were conducted to evaluate the effect of incorporated hydrogel amendments to a soilless growth medium on ammonium, nitrate, and water retention and tomato (Lycopersicon esculentum Mill.) seedling growth. HydroSource and Agri-gel were incorporated into a 1 peat: 1 perlite: 1 vermiculite soilless medium at rates of 1, 2, or 3 g·liter-1 with 0.88 g of ammonium nitrate fertilizer. Water retention by the growth medium increased linearly with gel application; HydroSource generally was more effective than Agri-gel. Between 90% and 96% of the applied nitrate-N was recovered in the resulting leachate of the gel-amended media, while 33% to 55% of the ammonium-N was recovered. Nitrate-N and ammonium-N retention was higher when 3 g·liter-1 of either gel was added to the growth medium than when lower amounts or no gel was added. Gel amendment did not affect tomato seedling growth. Total foliar N concentration in tomato leaves was significantly higher in the HydroSource treatments than in the control or Agri-gel treatments.
Tolerance and Responses of Harvested Mango to Insecticidal Low-oxygen Atmospheres
Authors: Yahia Elhadi M. , Hernandez Martin Tiznado
Published: February 2019

`Keitt' mangoes (Mangifera indica L.) were stored for 0 to 5 days at 20C in a continuous flow of an insecticidal low-O2 atmosphere (0.2% to to 0.3%, balance N2). Fruit were evaluated every day after exposure to a low-O2 atmosphere and again after being held in air at 20C for 5 days. There was no fruit injury, organoleptic fruit quality was not lowered due to the low-O2 atmosphere, and fruit ripened normally. These results indicate that applying low-O2 atmospheres postharvest can be used to control insects in mangoes.
Measuring Transpiration Rates of Tomato and Other Detached Fruit
Authors: Shirazi Ahmad , Cameron Arthur C.
Published: February 2019

A method was developed to measure transpiration rates and apparent water-vapor permeability coefficients (P'H2O) of detached fruit using an analytical balance equipped with a humidity chamber, wide-range humidity-generating and sensing devices, and a datalogger. The system was designed to monitor weight changes with time and, hence, weight loss of individual fruit during exposure to specific relative humidities (RHs) and temperatures. Weight loss was corrected for loss due to respiratory exchange of 02 and CO2 before calculating P'H2O. Values of P'H2O for tomatoes obtained using this method over periods of 5 minutes to 24 hours ranged from 3 to 12 nmol·cm-2·s-1·kPa-1 at 20C, depending on the experimental conditions. These values are similar to previously published values and to those obtained in a conventional weight-loss experiment, which involved intermittent weighing. P'H20 for tomatoes dropped ≈15% in 24 hours. P'H20 increased with a transient increase in RH; the extent of the increase was variable from fruit to fruit, ranging from 5% to 100% over 30% to 90% RH. The change was reversible in that P'H2O increased and decreased within minutes following shifts in RH. Similar changes were found for strawberry P'H20. The increase in P'H2O may be due, in part, to a direct effect of water vapor on the water transport properties of the cuticular polymer and surface temperature depression as a result of evaporative cooling. At 50% RH and 20C, water vapor diffuses from tomatoes 50 times faster than O2 enters on a molar basis. This information will be useful for modeling RH changes in modified-atmosphere packages.
In Vitro Hardening of Red Raspberry by CO2 Enrichment and Reduced Medium Sucrose Concentration
Authors: Deng Ribo , Donnelly Danielle J.
Published: February 2019

Micropropagated `Festival' red raspberry (Rubus idaeus L.) shoots were rooted in specially constructed plexiglass chambers in ambient (340 ± 20 ppm) or enriched (1500 ±50 ppm) CO2 conditions on a medium containing 0, 10, 20, or 30 g sucrose/liter. Plantlet growth and leaf 14CO2 fixation rates were evaluated before and 4 weeks after ex vitro transplantation. In vitro CO2 enrichment promoted in vitro hardening; it increased root count and length, plantlet fresh weight, and photosynthetic capacity but did not affect other variables such as plantlet height, dry weight, or leaf count and area. No residual effects of in vitro CO2 enrichment were observed on 4-week-old transplants. Sucrose in the medium promoted plantlet growth but depressed photosynthesis and reduced in vitro hardening. Photoautotrophic plantlets were obtained on sucrose-free rooting medium under ambient and enriched CO2 conditions and they performed better ex vitro than mixotrophi plantlets grown with sucrose. Root hairs were more abundant and longer on root tips of photoautotrophic plantlets than on mixotrophic plantlets. The maximum CO2 uptake rate of plantlet leaves was 52% that of greenhouse control plant leaves. This did not change in the persistent leaves up to 4 weeks after ex vitro transplantation. The photosynthetic ability of persistent and new leaves of 4-week-old ex vitro transplants related neither to in vitro CO2 nor medium sucrose concentration. Consecutive new leaves of transplants took up more CO2 than persistent leaves. The third new leaf of transplants had photosynthetic rates up to 90% that of greenhouse control plant leaves. These results indicate that in vitro CO2 enrichment was beneficial to in vitro hardening and that sucrose may be reduced substantially or eliminated from red raspberry rooting medium when CO2 enrichment is used.
Gamma Radiation Unpromising as an Insect Quarantine Treatment for Fraser Fir Branches
Authors: Hinesley L. Eric , Snelling Layne K.
Published: February 2019

Dormant branches of Fraser fir [Abies fraseri (Pursh) Poir.] Christmas trees were subjected to single doses of gamma radiation at levels ranging from 0 to 5.0 kGy (0 to 500 kRad). Significant needle loss resulted at doses ≥0.10 kGy and increased with radiation intensity. Irradiation discolored foliage and accelerated drying. Irradiation does not appear to be a viable way to meet insect quarantine requirements on cut Fraser fir Christmas trees.
Microsprinkler Irrigation of Young `Redblush' Grapefruit Trees Using Reclaimed Water
Authors: Maurer Michael A. , Davies Frederick S.
Published: February 2019

Two field studies conducted from 1990 to 1991 evaluated the effects of reclaimed water on growth and development of 1- and 2-year-old `Redblush' grapefruit (Citrus paradisi Macf.) trees on Swingle citrumelo [Citrus paradisi (L.) Osb. ×Poncirus trifoliata (L.) Raf.] rootstock. Treatments were arranged as a3 (water sources) x 3 (irrigation levels) factorial at two locations on an Arredondo (well drained) and Kanapaha (poorly drained) fine sand near Gainesville, Fla. Irrigation treatments included 1) reclaimed water, 2) reclaimed water plus fertigation, and 3) well water plus fertigation. The reclaimed water was formulated to simulate that of a sewage treatment plant at Vero Beach, Fla. Irrigation was applied at 20% soil moisture depletion, or at 19 or 25 mm·week regardless of rainfall. In both experiments, visual ratings of tree vigor, and measured tree height and trunk diameter, were significantly lower for trees watered with reclaimed water without fertilizer than for the others in both years. Moreover, there was no fourth leaf flush in 1991 with reclaimed water. There was a significant increase in leaf Na, Cl, and B concentrations for the reclaimed water and reclaimed water plus fertigation treatments in 1990; however, in 1991 only leaf B concentrations showed a similar trend. In 1991, there were no significant differences in leaf Cl concentrations. Visual symptoms of N deficiency were observed by the end of the first season in trees grown with reclaimed water. Irrigation levels generallv did not affect tree growth.
Variation in Soil pH and Calcium Status Influenced by Microsprinkler Wetting Pattern for Young Citrus Trees
Authors: Alva AK. , Obreza T.A.
Published: February 2019

Deep aquifer water, which contains high levels of bicarbonate and Ca, is used predominantly for citrus irrigation. Changes in soil pH and Mehlich 1 extractable Ca concentrations were examined inside and outside the microsprinkler-wetted zone in 3- to 5-year-old citrus groves on three soils. Soil pH at 0 to 15 cm inside the wetted zone was 0.4, 0.9, and 1.3 pH units higher than that outside the wetted zone in Immokalee, Myakka, and Holopaw sands, respectively. This pH increase was due to the addition of bicarbonate in the irrigation water. Extractable Ca concentrations were also about two-fold higher inside compared to those outside the wetted zone at depths of O to 15 and 15 to 30 cm. With young trees, a majority of the roots are within the microsprinkler-wetted zone; therefore, soil samples should be taken inside the wetted zone for measuring soil pH and status of plant nutrients.
COMPARATIVE STUDY OF WATER ECONOMY OF CONTAINER-GROWN WOODY ORNAMENTAL SHRUBS
Authors: Boehm E.C. , Davis T.D. , Kuti J.O.
Published: February 2019

Relative water usage of four species of container-grown woody ornamental shrubs (Buxus japonica (Japenese boxwood), Leucophyllum frutescens (Texas sage), Ligustrum japonica (ligustrum) and Pittosporum tobira wheeleri (dwarf) pittosporurm)), normally used for home landscaping in south Texas, were evaluated by comparing water consumption and frequency of watering with growth rates and horticultural quality after six months growth in containers. Growth rates were determined by the difference in plant height and leaf area from the control unwatered plants and were used to characterize the suitability of ornamental shrubs for xeric landscapes. While frequency of watering had no significant effects on plant height, only ligustrum and dwarf pittosporum plants watered on weekly basis showed positive change in leaf area. There was considerable leaf regrowth in Texas sage plants after initial leaf loss. Of all the shrubs tested, dwarf pittosporum plants watered biweekly used less water to maintain their horticultural quality.
A Simple Transformation System Using Adventitious Shoot Multiplication of Juneberry
Authors: Hajela Ravindra K. , Hajela Neerja , Bolyard Mark G. , Barnes Wayne M. , Sticklen Mariam B.
Published: February 2019

A simple gene transfer method based on Agrobacterium -mediated transformation of adventitious multiplication of Juneberry (Amelanchier laevis L.) basal shoots is described. Evidence is presented for successful integration and expression of a transformed gene in greenhouse-grown transgenic plants. This method can transform woody perennials that are difficult to regenerate from leaf disks, protoplasts, or other tissue culture regimens.
The H.O.R.T Project: A Hands-on Educational Experience
Authors: Wees David
Published: February 2019

The Farm Management and Technology Program (FMT) is a 3-year post-secondary vocational agriculture program. FMT students may choose to specialize in horticulture. Since January 1995, all horticulture students have been involved in a hands-on, practical educational experience called “H.O.R.T.” (Horticultural Opportunities for Real Training). The students operate a small horticultural “business.” They must plant, maintain, harvest, and sell several horticultural crops, including greenhouse and field-grown vegetables, apples, berries, and potted flowers. H.O.R.T. lasts two semesters: January through April and September through December. Students may choose to do H.O.R.T. for 2 years to broaden and deepen their horticultural learning. Through active participation in H.O.R.T., students will achieve the technical competencies required by the FMT program and specified by Quebec's ministries of education and agriculture. Each year of H.O.R.T. counts for 5-2/3 credits out of a program total of 90-1/3 credits. The goals of H.O.R.T. are not so much the acquisition of “book knowledge” (lower part of the cognitive domain) as the development of technical skills, planning and decisionmaking abilities, business sense, and proper communication (higher-order cognitive skills as well as psycho-motor and affective skills).
Leaching Characteristics of P From Four Fertilizer Sources in a Container Nursery Growing Medium
Authors: Cole Janet C. , Dole John M.
Published: February 2019

A 3 pine bark: 1 peatmoss: 1 sand (by volume) medium was amended with 7.7 g P as superphosphate, triple superphosphate, ammonium phosphate, or controlled-release ammonium phosphate per 1000 g medium (3.8 liters). The medium was then leached with 250, 350, or 450 ml distilled, deionized water daily for 25 days. Phosphorus leaching curves were then generated for each fertilizer. A subsequent study determined the effect of these four P fertilizers on growth of marigold seedlings in the greenhouse. Superphosphate, triple superphosphate, and ammonium phosphate rapidly leached from the medium, while the controlled-release ammonium phosphate was retained for a longer time. Marigold growth was not affected by fertilizer type; however, marigolds grown in P-amended media were larger than those grown without P. These studies indicate that amending container growing medium with superphosphate or triple superphosphate prior to planting may not be cost-effective.
The Effect of Avocado Clonal Rootstock on Productivity and Tree Vigor of `Hass' Avocado
Authors: Arpaia M.L. , Bender G.S. , Witney G.W.
Published: February 2019

A project evaluating the performance of cv. Hass on eight clonal avocado rootstocks—G755A, G755B, G755C, Duke 7 (D7), Borchard (BR), D9, Toro Canyon, and Topa Topa was established in southern California in 1986. Two additional rootstocks, Thomas and G1033, were added in 1987. Of the trees planted in 1986, the BR and D7 rootstocks have consistently had the highest total yields for all rootstocks, whereas the three G755 selections have had the lowest productivity. No differences in productivity between the two rootstocks planted in 1987 have been detected. The influence of rootstock on the magnitude of alternate bearing will be discussed, although the oscillation in yield is greater for the higher-yielding rootstocks. Tree size has been measured throughout the study. The BR selection has consistently produced a larger tree, even though it has continued to have high productivity. There are no consistent differences between the other rootstocks. Yield efficiency, measured as the kg fruit/m3 of canopy volume has been calculated. In selections that are prone to severe alternate bearing, the swing in yield efficiency is also the greatest. The data thus far suggests that a yield efficiency of ≈2.5 kg fruit/m3 canopy volume is the maximum yield possible for California `Hass' avocado.
Genetic Parameters for Traits Related to Mechanized Harvesting in a Cucumber (Cucumis sativus L.) Population
Authors: Serquen F. , Staub J.
Published: February 2019

Sex expression (SE), stem length (SL), and number of laterals plant (NL) are important morphological traits of a cucumber plant ideotype adapted for machine harvesting. Two inbred lines, the determinate, gynoecious G-421, possessing high fruit quality, and the monoecious H-19, with multiple lateral branching and sequential fruiting habit, and their F1 and F3 (100) progenies were planted in Wisconsin and Georgia. Data on SE, SL, and NL were recorded on individual plant basis. Genetic parameters were estimated using all generations. Phenotypic correlations were calculated from the trait means, and genotypic correlations were estimated from the analysis of variance of F3 progeny. The additive genetic variance was the highest of the variance components for SL and NL. Dominance genetic variance was more important than the additive variance for the control of SE. Narrow-sense heritability were 0.41, 0.83, and 0.85 for SE, SL, and NL, respectively. The genotypic (g) and phenotypic (p) correlation coefficients (r) indicated negative association between SE and SL (rg = –0.57, rp = –0.45**) and between SE and NL (rg = –0.56, rp = –0.27**). The association between SL and NL was positive (rg = 0.63, rp = 0.35**). Results suggest that gain from selection can be made for this plant ideotype.
PCR Amplification of Persimmon Fruit β-Galactosidase
Authors: Kang I.K. , Starrett D.A. , Suh S.G. , Byun J.K. , Gross K.C.
Published: February 2019

We are studying β-galactosidase (EC 3.2.1.23) in softening persimmon fruit (Diospyros kaki L.f. cv Fuyu) and hope to decrease the rate of softening by inserting an antisense construct of the β-galactosidase gene. The N-terminal amino acid sequence of persimmon fruit β-galactosidase was recently reported. Here we report the cloning of a putative β-galactosidase gene from persimmons. Degenerate oligonucleotide primers were synthesized based on the amino acid sequence. 5′-RACE (rapid amplification of cDNA ends) was done using persimmon Poly A+ mRNA extracted using a phenol: chloroform/LiCl method. Purification was done on an oligo dT-cellulose column. A fragment of roughly 150 base pairs was purified by agarose gel electrophoresis and subcloned into the pCR-Script cloning vector from Stratagene. After sequencing and verifying the insert's identity, it will be isolated and used to screen a persimmon fruit cDNA library currently being constructed. Ultimately this cDNA clone will be used to make an antisense β-galactosidase construct that will be transformed into persimmon.
Involvement with Flavonoids on Chlorophyll Degradation by Peroxidase in Wase Satsuma Mandarin Fruits
Authors: Yamauchi Naoki , Xia Xiao-Ming , Hashinaga Fumio
Published: February 2019

Effects of flavonoid pigments on chlorophyll (Chl) degradation by Chl peroxidase in the flavedo of Wase satsuma mandarin (Citrus unshiu Marc. var. praecox Tanaka) fruits were studied. Chl was degraded when hydrogen peroxide was added in a reaction mixture containing Chl and a phosphate buffer extract from the flavedo. Chlorophyllide, which was formed by the action of chlorophyllase in the extract, was also degraded. The flavonoid contents decreased with the Chl degradation in the reaction mixture. Analysis of the flavonoid with HPLC showed that hesperidin and narirutin were contained in the flavedo as a major flavonoid, and that the former decreased significantly and the latter showed almost no change with the Chl degradation in the reaction mixture. In the ethylene-treated fruits, the hesperidin content in the flavedo also decreased with the degreening of stored fruits, suggesting that the flavonoid oxidation by Chl peroxidase could be involved in the Chl degradation.
Importance of Introgressive Hybridization in the Development of Invasive Lythrum salicaria
Authors: Anderson Neil O. , Ascher Peter D. , Liedl Barbara E.
Published: February 2019

Since its evolution as an invasive species in Quebec (1930s), L. salicaria has spread across North American wetlands virtually unchecked. Initially, it was theorized that the rapid invasion was due to the absence of phytophagous insects (present in the native habitat). However, evolutionists theorized that invasive characteristics probably arose from introgressive hybridization with a native species (L. alatum), since their ecotypes overlap. Several horticultural cultivars are also fertile interspecific hybrids. These two species differ for diagnostic traits (number of flowers/axil, plant height, phyllotaxy, style morphology, seed dormancy). Minnesota L. salicaria populations were examined for evidence of introgression. Lythrum salicaria introgressive genotypes were found for all diagnostic traits. Seed dormancy was the most common, i.e., OP seed showed significant seed dormancy (F = 5.2, P = 0.024). Such hybrids would have adaptive advantages as weeds, having evolved for each ecotype by introgression with locally adapted L. alatum populations.
Influence of Potassium (K) and Cultivar on Watermelon Quality
Authors: Akinbolu A. , Huber D.J. , Hochmuth G.J. , Aworh O.C.
Published: February 2019

The influence of potassium (K) on respiratory behavior, flesh firmness, and internal color of watermelon (Citrullus lanatus) was studied. Two cultivars (Crimson Sweet and Sangria) were planted at the Univ. of Florida research station, Gainesville. The fruits from both cultivars were harvested at two different stages of maturity (25 days and 35 days after anthesis). Respiration and ethylene production were measured using gas chromatography under a static system. The internal color was measured by a colorimeter, while the flesh and rind firmness were measured by a instron Universal pressure tester. Carbon dioxide and ethylene production were non-climacteric in behavior and were not greatly affected by K treatment or cultivar.
Gamma-ray-induced Changes in Plasma Membrane from Hypodermal Mesocarp Tissue of Muskmelon Fruit
Authors: Lester Gene E. , Whitaker Bruce D.
Published: February 2019

Postharvest gamma-irradiation of melons at low dosage has been reported to extend shelf life. This study assessed how irradiation alters the structure and function of plasma membrane (PM) from hypodermal-mesocarp tissue. Administration of gamma rays (1 kGy at 0.017 kGy/min) to mature melon (Cucumis melo L.) fruit caused a 14% drop in H+-ATPase activity within 4 h. Total protein content did not differ in PM from non-irradiated (NIR) vs. irradiated (IR) fruits. Following storage (7 days at 7C then 3 days at 21C), H+-ATPase activity was ≈10% to 20% lower in PM from both groups of fruit, with no difference between the two. Total PM protein had declined by 34% and 49% in IR and NIR fruits, respectively. After irradiation, the phospholipid to protein ratio (PL:protein) was substantially higher in PM from IR fruit (0.67 vs. 0.58 in NIR). With storage, PL:protein dropped to 0.52 in NIR fruit PM, but changed little (0.65) in IR fruit PM. These results may indicate that irradiation stimulates PL synthesis or inhibits PL catabolism. Further analyses of PM lipid content and composition are underway.
Chromosome Numbers of Rubus Accessions in the USDA/ARS National Clonal Germplasm Repository, Corvallis, Ore.
Authors: Thompson Maxine M. , Hummer Kim E.
Published: February 2019

Chromosome numbers were determined for the Rubus species and cultivars held at the USDA/ARS National Clonal Germplasm Repository, Corvallis, Ore. Counts were made on a total of 205 taxa; 81 of which were new, 124 were corrections, and a few were corrections of previous reports. The numbers ranged from 2n = 2x = 14 to 2x = 98, and included odd-ploids and aneuploids. Knowledge of the chromosome number of a plant is important for its use in breeding because of potential sterility problems that may arise due to unbalanced gametes. The value of these particular counts are that they are vouchered by a permanent, living plant collection that is available to the scientific user community.
Twospotted Spider Mite Presence on 40 Rubus Species.
Authors: Finn Chad , Wennstrom Kirsten
Published: February 2019

Twospotted spider mites (Tetranychus urticae Koch) can be a serious pest on Rubus, primarily red raspberry, in the Pacific Northwest. As we expand the Rubus germplasm in our breeding program, we must evaluate new material for its susceptibility or resistance to pests. Populations of 40 Rubus sp., representing the Malachobatus, Idaeobatus, Eubatus, and Anoplobatus, as well as `Meeker' and `Marion', were evaluated for mite presence in either a replicated or observation trial. Fully mature leaves, 10 in the replicated trial and 15 in the nonreplicated trial, were harvested at random from 15 to 60 cm above the soil surface. Mature, motile mites were counted on the lower surface of the leaves using a dissecting microscope. Because leaf size was extremely variable from species to species, leaf area was measured and a mite density calculated. There were significant differences in mite density among the species in the replicated trial. The average mite density was 0.03 mites/cm2, and mite densities were high on one population of R. Iambertianus and R. hunanensis, 2.7 and 1.6 mites/cm2, respectively. In the nonreplicated trial, R. glabratus had the highest mite density (2.3 mites/cm2). A population of R. corchorifolius (1.0 mites/cm2) and R. parviflorus (0.9 mites/cm2) had fairly high mite densities. In both plantings, many of the populations had few or no mites.
Partitioning of a Drought-induced Root Signal within the Fragaria chiloensis Plant
Authors: Archbold Douglas D. , Cheng Lailiang
Published: February 2019

Plants of Fragaria chiloensis cv. RCP-37 were grown with their root system split between two separate containers. Water was withheld from one container of each pair (drought side), while the other was subirrigated. Control plants were subirrigated in both containers. Over several days, a drought-side leaf exhibited reductions in stomatal conductance (gs) and transpiration rate (T), while a subirrigated side leaf showed no change in either parameter. However, foliar water relations components (water, osmotic, and pressure potential) did not differ between the two leaves. The leaf on the subirrigated side exhibited gs, T, and water relations components similar to leaves on control plants. The abscisic acid (ABA) content of xylem exudate, collected from a stolon emerging from the axils of the measured leaves, was highest from the drought side and was negatively correlated to gs and T at some sampling dates. A root-derived drought stress signal, perhaps ABA, although other factors cannot be discounted, was limited within the plant to the drought side, even though water relations components indicated that water from the subirrigated side was allocated to all parts of the plant.
Water Relations, Stomatal Conductance, and Abscisic Acid Content of Young Apple Trees in Response to Antitranspirant Treatment
Authors: Guak Sung H. , Cheng Lailiang , Fuchigami L.H.
Published: February 2019

Potted apple trees (Malus domestica L. `Gala') were drenched with either water or an antitranspirant (N-2001). After treatment, no additional water was applied to the plants. Abscisic acid (ABA) content of immature and mature leaves was determined by radioimmunoassay after 0, 1, 3, and 5 h and 1, 2, 4, 7, 8, and 9 days after treatment. ABA content of mature and immature leaves of antitranspirant-treated plants peaked 1 and 4 days after treatment, respectively, and remained constant thereafter. In contrast, with increasing water stress, the ABA content of mature and immature leaves of control plants without antitranspirant peaked at 7 and 8 days, respectively. The overall level of ABA in mature leaves of both treatment groups was significantly greater than in immature leaves. The water saturation deficit increased, water and turgor potentials of leaves decreased, and stomatal conductance decreased in response to antitranspirant application. The changes in water relations parameters and stomatal conductance were highly correlated with changes in leaf ABA content.
Searching for the Best Empirical Model to Estimate Turf Water Use in Kansas
Authors: Wiest Steven C. , Fry Jack D. , Upham Ward S.
Published: February 2019

A relatively accurate estimate of turfgrass evapotranspiration (ET) using environmental parameters readily obtainable from a local weather station would be of benefit to golf course superintendents, landscape managers, and homeowners. The Penman–Monteith model is clearly a poorer estimate than that obtained by Bellani plates or spheres. It has been suggested that, while the Penman–Monteith model is good in the drier climate of the southwestern United States, other models may be of greater practicable utility in climates such as are common in Kansas. Thus, other models have been evaluated for their suitability as turfgrass ET estimates in Kansas-like climates. Turfgrass ET was measured via lysimeters in 1992–94. Specifically, measurements were taken on three tall fescue varieties mowed at 6.35 or 7.62 cm, and zoysiagrass and perennial ryegrass mowed at 2.54 cm. Evaporation from black Bellani plates was measured simultaneously. These evaporation and ET rates were compared to those estimated by various empirical models whose data came from a weather station located within 31 m of the Bellani plates and lysimeters. Empirical models included temperature methods (e.g., FAO-24 Blaney–Criddle), radiation methods (e.g., Jensen–Haise, Hargreaves–Samani), combination equations (e.g., Priestly–Taylor, Penman), and variants. The best model(s) determined from these comparisons will likely become the method(s) of choice for estimating turfgrass ET in Kansas.
Rooting Systems of Semi-hardwood Olive Cuttings of Three Selected Varieties of Manzanilla, Sevillana, and Clonavis
Authors: Talaie A.R. , Malakroodi M. Ramazani
Published: February 2019

Propagation testing of semi-hardwood olive cuttings was conducted to ensure adequate production to meet Iranian needs. `Clonavis', `Sevillana', and `Manzanilla' were selected to investigate their rooting situations. Three variables (cultivar, differential concentrations of IBA, and vertical cut in the basal end of the cuttings) were considered in a randomized complete-block factorial design test with four replications with 10 cuttings in each treatment. Cuttings 10 to 15 cm long and 0.5 to 1.5 cm in diameter were taken from each cultivar. IBA (0, 2000, 3000, and 4000 ppm) was used in two vertical cuts in basal end of half of the cuttings. Statistical analysis of the rooting capability differed for the three cultivars. `Sevillana' and `Clovanis' rooted better than `Manzanilla'. IBA at 3000 ppm resulted in the highest rooting percentage in all cultivars. The maximum number of roots was obtained with IBA at 4000 ppm in roots that had the basal cuts. Basal end cuts affected considerably the rooting percentage and number of roots, but had no effect on increased root length.
Evaluation of SCAR Markers to Identify Raspberry Cultivars
Authors: Parent Jean-Guy , Page Daniele
Published: February 2019

Random amplified polymorphic DNA (RAPD) markers are used in Quebec's certification program to verify the identity of raspberry cultivars. However, sequence characterized amplified region (SCAR) markers, less sensitive to modifications in reaction conditions, could be derived from RAPD markers. Our objective was to evaluate the potential of SCAR markers to replace the RAPD ones. Five RAPD markers obtained with primer OPG06 (length of 520, 700, 825, 1450, and 2000 bp) were cloned in pTZ/PC or pCRII vectors. Extremities of the cloned markers were sequenced by the nonradioactive silver sequence method using pUC/M13 forward and reverse primers. Sequence information was used to make SCAR primers, similar in length to standard PCR primers. Some SCAR primers were elongated RAPD primers, whereas others were from internal regions. Ability of primer pairs and combination of primer pairs to discriminate cultivars of our certification program was compared with their RAPD counterparts as well as with the technical feasibility of both methods.