bluuebunny/crossref_metadata_2025 huggingface dataset:
Pruning Method Influences Stem Length and Number of Four Woody Cut Species
Authors: Dole John M. , Cole Janet C. , Stamback Vicki
Published: February 2019

Rooted cuttings of four woody cut species, Buddleia davidii `Black Knight' (butterfly bush), Forsythia × intermedia `Lynwood Gold', Salix chaenomeloides (Japanese pussywillow), and Salix matsudana `Tortuosa' (corkscrew willow) were planted outdoors in 23 Apr. 1992. During the next year, forsythia, pussywillow, and corkscrew willow plants were either unpruned or pruned to 30–45 cm above the ground: 1) during dormancy or immediately after harvest (winter); 2) 3 to 4 weeks after start of shoot growth (spring); or 3) in early June (summer), and number and length of stems harvested was recorded for three years. Butterfly bush was either unpruned or pruned to 8 cm above the ground during: 1) winter or 2) spring, and number and length of stems recorded for 2 years. Stem length and number increased each year for all four species, and all species produced harvestable stems within 1 year after planting. For forsythia, no differences due to treatment were found, although year by treatment interactions were noted. The unpruned control produced the longest and greatest number of stems for pussy willow. Winter or spring pruning produced the longest and greatest number of stems for corkscrew willow. For butterfly bush, spring or no pruning produced the greatest number of stems, and year by treatment interactions were noted.
Volatile Profiles of Microorganisms on Various Substrates, Including Fruits and Vegetables
Authors: Perez Rufino , Linz John , Rasick Matt , Beaudry Randolph M.
Published: February 2019

Minimally processed fruits and vegetables, by virtue of cell disruption resulting from processing and handling, can encourage the growth of microorganisms. There is potential for identification of microorganisms and characterization of microbial products and constituents in food, based on volatile profile analysis. We have prepared a flow-through system to grow several bacteria including E. coli 25922-ATCC and E. coli 0157:H7 and monitored the volatile profiles under conditions similar to those experienced by minimally processed fruits and vegetables during marketing conditions. Specific volatiles have been identified that may have potential to serve as signature-type volatiles in accurate automated quality control systems. For example, indole and a number of short-chain fatty acids are produced in copious amount by E. coli 25922-ATCC, but are not constituent of broccoli or carrot aroma profiles. The data suggest that specific volatiles may serve as “markers” for bacterial presence.
The Temporal Relationship between Volatile Biosynthesis and Other Ripening Parameters in Banana Fruit
Authors: Song J. , Rubinstein N. , Beaudry R.M
Published: February 2019

Banana [Musa sp.9AAA group0, Cavendish] fruit are climacteric in nature, undergoing a rapid rise in ethylene production and respiration. Ethylene production can peak within 8 h of a detectable rise in production and respiration peaks within 24 h. These rapid changes permit precise timing for events related to or dependent on ethylene presence. Using rapid analytical methodology, we investigated the dynamic changes in volatile biosynthesis and its relation to other ripening parameters. Ungassed, mature-green banana fruit were placed individually at 23°C in flow through glass chambers. Ethylene production, respiration, chlorophyll fluorescence, skin color (hue angle) and volatile production were monitored. The climacteric rise and subsequent fall in ethylene production was found to be complete within 20 h. The respiratory rise peaked 20 h after the initial rise in ethylene production. The onset of the decline in chlorophyll fluorescence, skin color (hue angle) were coincident with the rise of ethylene and respiration, which indicated that the chlorophyll fluorescence may be used to monitor the banana fruit ripening. Volatile production was found to begin ≈60 h after the onset of the ethylene climacteric, peaking 3 to 4 days later. The ester precursors butyric acid and 3-methylbutanol were used in feeding experiments at different developmental stages for pulp and peel. Full ester-forming capacity was found to exist well before the onset of volatile biosynthesis. There were also different biosynthetic capacities for pulp and peel. Low aroma production in pre-climacteric fruit is apparently limited by the supply of precursors, which may be derived from the ethylene-induced enhancement of fruit respiratory metabolism.
Vernalization and Growing Degree-day Requirements of Thalictrum delavayi `Hewitt's Double'
Authors: Funnell Keith A. , MacKay Bruce R. , Huang Ning
Published: February 2019

Vernalization and growing degree-day requirements of Thalictrum delavayi `Hewitt's Double' were determined to improve the production scheduling of this cut flower crop. Two-year-old crowns of T. delavayi `Hewitt's Double', lifted in the fall, were exposed to cold storage for 0, 3, 6, 9, 12, or 15 weeks at 8 ± 1°C. After storage, the containerized plants were grown at Massey Univ., Palmerston North (40°20.S) in a greenhouse heated at 15°C and vented at 20°C, under a natural photoperiod (11 h increasing to 13 h) plus a 4-h night interruption between 2200 and 0200 HR. As buds continued to develop during storage at 8°C, growing degree-days calculations were made over both storage and greenhouse forcing periods. All plants flowered, but T. delavayi `Hewitt's Double' nevertheless showed a quantitative vernalization requirement, being fully saturated after 6 weeks of cold storage at 8°C. With a base temperature of 0°C, time to flowering reduced from 3338 degree-days without vernalization to an average 2804 degree-days subsequent to the saturation of the vernalization response (6 to 15 weeks of vernalization). Flower yield averaged between three and five stems per plant, with stem lengths ranging between 140 and 200 cm. Differences in flower yield and quality among storage durations were minor and not commercially significant.
Photoperiod and Temperature Interact to Affect Petunia × hybrida Vilm. Development
Authors: Erwin J.E. , Warner R. , Smith G.T. , Wagner R.
Published: February 2019

Petunia × hybrida Vilm. cvs. `Purple Wave', `Celebrity Burgundy', `Fantasy Pink Morn', and `Dreams Red' were treated with temperature and photoperiod treatments for different lengths of time at different stages of development during the first 6 weeks after germination. Plants were grown with ambient light (≈8–9 hr) at 16°C before and after treatments. Flowering was earliest and leaf number below the first flower was lowest when plants were grown under daylight plus 100 μmol·m–2·s–1 continuous light (high-pressure sodium lamps). Flowering did not occur when plants were grown under short-day treatment (8-hr daylight). Plants grown with night interruption lighting from 2200–0200 HR (2 μmol·m–2·s–1 from incandescent lamps) flowered earlier, and with a reduced leaf number compared to plants grown with daylight + a 3-hr day extension from 1700–2000 HR (100 μmol·m–2·s–1 using high-pressure sodium lamps). Plant height and internode elongation were greatest and least in night interruption and continuous light treatments, respectively. `Fantasy Pink Morn' and `Purple Wave' were the earliest and latest cultivars to flower, respectively. Flowering was hastened as temperature increased from 12 to 20°C, but not as temperature was further increased from 20 to 24°C. Branching increased as temperature decreased from 24 to 12°C. Implications of data with respect to classification of petunia flower induction and pre-fi nishing seedlings are discussed.
Development of a Cultural Production System for Gobo (Japanese Burdock)
Authors: Sanders D.C. , Frick Jay , Jester W.R.
Published: February 2019

`Takinogawa Long' gobo was seeded with two, three, or four rows per 1.5-m bed at in-row spacings of 7.5, 15, 21.5, and 30 cm. Total and marketable increased with in-row spacing and marketable yield increased with row number with the greatest yields occurring at 15, regardless of row number. Average root weight and yield of forked roots was not affected by row number, but increased with in row spacing. Similarly, percentage of forked roots decreased with more rows per bed. The 15-cm in-row spacing had the greatest yield, but also the greatest weight of culled roots, but none of the populations affected the percentage culls. In another study, in-row subsoiling (SS) and in-row banded phosphorus (P) were evaluated. Marketable yield was increased by both SS and P, but they did not interact. P increased average root weight. Neither SS or P affected forked root yield or cull root yield, but SS decreased forked roots and increased cull production.
Yield Mapping of Vegetable Crops
Authors: Hollist Ray R. , Campbell Ronald H. , Campbell Robert
Published: February 2019

Over the past few years, grain yield monitors have gained a significant hold in the market place. While the largest share of production agriculture acres are devoted to producing grain crops, high-value crops such as potatoes, tomatoes, sugarbeets, onions, and many others will benefit considerably by application of site-specific technology. Yield mapping is one of the tools that utilizes GPS technology and allows us to visualize our farms as an array of tiny parcels instead of one uniform aggregate. Yield mapping is simple, accurate measurement of yield at precise positions, the data from which is used to give us a visual report card of each parcel in that field. While yield mapping will not provide the entire basis of site-specific agriculture management, it begins to give a picture of how understanding spatial variation will revolutionize management of high-value crop production acres. The tools necessary to make yield measurements are now available. When combined with Differential GPS, the yield map becomes a powerful tool to identify atypical areas in the field. Without DGPS the process of identifying and treating areas within a field individually would be a nearly impossible task, and certainly cost-prohibitive. Identification of the spatial distribution of yield will contribute significantly to a grower's ability to make informed management decisions.
Cultivar Variation in Responses of Strawberry Fruit to High Carbon Dioxide Treatments
Authors: Watkins C.B. , Manzano-Mendez J.E. , Nock J.F. , Zhang J. , Maloney K.E.
Published: February 2019

The tolerances of strawberry fruit to postharvest CO2 treatments is an important factor in assessing their potential for extended storage and marketing, but little information on variation among cultivars is available. We have assessed differences in responses of seven strawberry cultivars (`Annapolis', `Earliglow', `Kent', `Honeoye', `Cavendish', `Jewel', and `Governor Simcoe') to high-CO2 atmospheres. Fruit were harvested at the orange or white tip stage of ripeness, kept in air, or 20% CO2 (in air), and sampled after 1, 2, or 7 days for analysis of firmness, color, and volatile concentrations. Berries from each cultivar were collected on three separate harvest dates. Flesh firmness measurements of all cultivars tested were higher when treated with high CO2, but the degree of firming was affected by cultivar and assessment time. For example, firmness of `Annapolis', `Earliglow', `Honeoye', and `Jewel' was consistently enhanced by CO2, compared with air, during storage. In contrast, firmness of `Kent' was not affected by treatment after 1 day of storage and benefits were relatively slight at each subsequent removal. Red color development of the fruits was affected by cultivar and treatment period, but not by CO2 treatment. Volatile accumulation varied greatly among cultivars. `Annapolis' for example, appears very tolerant of high-CO2 treatment levels as indicated by low accumulations of ethanol, acetaldehyde, and ethyl acetate in the fruit. In contrast, `Kent' and `Governor Simcoe' accumulated large amounts of these compounds. This study indicates that differences in cultivar responses to CO2 should be considered by growers planning to store fruit under these conditions to extend marketing options. Research supported in part by the North American Strawberry Growers Association.
Impact of Temperature on Apple Fruit Growth
Authors: Warrington I.J. , Fulton T.A. , Halligan E.A. , Austin P.T. , Hall A.J. , Gandar P.W.
Published: February 2019

Apple fruitlet growth responses to temperature were studied, for different durations following bloom (DAFB), under controlled environment (CE) conditions. Container-grown trees of `Red Delicious', `Golden Delicious', `Braeburn', `Fuji', and `Royal Gala' were placed in different maximum/minimum temperature regimes, ranging from 9/3 to 25/15°C for various periods, including 10–40, 10–80, and 40–80 DAFB. Temperature treatments were selected to identify possible differences between mean and maximum/minimum differential effects Trees were placed outdoors following the CE treatment to allow impacts on subsequent fruit development to be determined. The impact of temperature was dramatic. For example, fruit expansion rate for `Red Delicious' varied from 0.12 mm/day at 9/3°C to 0.98 mm/day at 25/15°C. Furthermore, the cell division phase was considerably longer under cooler temperatures. The influence of post-bloom temperature, for even short durations, was evident at harvest in both fruit size and in different fruit maturity indices. Differences in temperature sensitivity were evident amongscultivars. A detailed model has been developed to integrate the responses that have been determined.
Drought Resistance among Freeman Maples
Authors: Zwack James A. , Graves William R. , Townsend Alden M.
Published: February 2019

Freeman maples (Acer × freemanii E. Murray) are marketed as stress-resistant alternatives to red maples (Acer rubrum L.), but few data from direct comparisons of these species are available. As a first step in comparing the stress resistance of red maple and Freeman maple, responses to drought were studied in Acer × freemanii `Autumn Fantasy', `Celebration', and `Marmo'. Plants grown from rooted cuttings were treated by withholding irrigation through four drought cycles of increasing severity that were separated by irrigation to container capacity. Drought reduced shoot dry mass, root dry mass, and height growth by 64%, 43%, and 79%, respectively, over all cultivars. Predawn leaf water potential was reduced by 1.16 MPa over all cultivars, and stomatal conductance data indicated water use was more conservative over all root-zone moisture contents after repeated cycles of drought. Specific mass of drought-stressed leaves increased by 25% for `Autumn Fantasy', and microscopy to determine leaf thickness and cellular anatomy is ongoing. `Autumn Fantasy' also had the lowest ratio of leaf surface area to xylem diameter, and `Autumn Fantasy' and `Celebration' had higher ratios of root to shoot mass than `Marmo'. Pressure-volume curve analysis revealed osmotic potential of drought-stressed plants at full turgor was 0.24 MPa more negative than controls, and droughted plants had a greater apoplastic water percentage than controls. Although osmotic adjustment during drought was similar among cultivars, differences in specific mass of leaves and in ratios of transpiring and conducting tissues suggest cultivars of Freeman maple vary in resistance to drought in the landscape.
Effects of Different Cytokinin-like Compounds on Invertase Activity during Potato in Vitro Tuberization
Authors: Kefi Servet , Meagher M.M. , Read P.E. , Pavlista A.D.
Published: February 2019

The effects of different cytokinin-like compounds on invertase activities at different tuberization stages of potato (Solanum tuberosum L. `Atlantic') were examined. Single nodal segments were cultured on MS medium plus 6% sucrose and supplemented with either 2 mg kinetin/L, 0.1 mg thidiazuron (TDZ)/L, 1.0 mg AC 243,654/L, 0.1 mg AC 239,604/L, or no cytokinin. Tissue samples for determining invertase activity were taken at three stages of tuberization: stage 1, the “hook stage”; stage 2, the “swelling stage”; and stage 3, “tuber initials.” Invertase activity was significantly affected by the interaction between cytokinin-like compounds and tuberization between cytokinin-like compounds and tuberization stages. The highest invertase activities in the stolons at stage 1 were found in kinetin and TDZ treatments. Invertase activity in the stolons on the control medium significantly increased from stage 1 to 2 and decreased at stage 3. Invertase might play a role in either stolon elongation or carbohydrate utilization by increasing the pool of reducing sugars.
Nitrogen Sources for Tomato and Pepper Production
Authors: Maynard Elizabeth T.
Published: February 2019

Three nitrogen sources applied through drip irrigation were compared to preplant-applied urea to evaluate their effects on tomato (Lycopersicon esculentum Mill.) and bell pepper (Capsicum annum L.) earliness, yield, and blossom end rot (BER) in 1995 and 1996. Calcium nitrate (CaNO3), urea ammonium nitrate (UAN), and ammonium nitrate (NH4NO3) were applied at 11.2 kg N/ha weekly beginning 2 weeks after transplanting for a total of 8 weeks. The urea treatment received 112 kg N/ha before planting and fertigated treatments received 22.4 kg N/ha from urea before planting. In 1995 only, two additional treatments were fertilized with chicken manure only (1.3N–0.7P–0.8K) at 112 kg N/ha and 168 kg N/ha. In 1996, nitrogen treatments were compared at two levels of potassium fertilization: 0 or 269 kg K/ha. `Sunrise' or `Mountain Spring' tomatoes and `Ranger' peppers were transplanted into black plastic in mid to late June each year. Nitrogen treatments had no effect on marketable or total yield, fruit size, or BER of tomatoes. Total pepper yield was lower with urea than with CaNO3; early and marketable yields showed similar trends, but differences were not consistently significant. UAN and NH4NO3 pepper yields were usually similar to yield with CaNO3, but did not always differ from urea yields. Compost treatments produced yields intermediate between urea and fertigated treatments in 1995. In 1996, peppers from UAN and NH4NO3 plots had more BER (0.5% to 1%) than CaNO3 plots (0%); urea plots had an intermediate amount of BER (0.2%).
Effect of Water and Nutrient Stresses on Apple Rootstock Growth, Respiration, and Capacitance
Authors: Psarras G. , Merwin I. , Lakso A. , Zobel R.
Published: February 2019

We are evaluating techniques for measuring intact apple rootstock (Malus domestica cv. M.9 and MM.111) responses to low, medium, and high soil-water potential, and low, medium, and high concentrations of N, K, and Ca, in sterile sand culture. Root respiration and functional surface area were estimated with an IRGA chamber and electric capacitance meter, respectively. Root length and surface area were determined by digital image analysis of extracted root systems. Low N supply reduced root respiration, while low K levels increased respiration relative to well-nourished controls. Calcium effects were inconsistent among the rootstocks. Total root length and respiration rates of MM.111 were higher than M.9, but M.9 had higher root:shoot ratios. Root capacitance was correlated with total root length (P < 0.001); and M.9 root systems had greater capacitance than MM.111. In a related field experiment, root growth and respiration of 4-year-old `Mutsu' apple trees on M.9 rootstock were measured in soil under low and moderate drought stress established by rain exclusion shelters, using capacitance and IRGA meters, and a minirhizotron video camera inserted into Plexiglas tubes transecting the rhizosphere. Root growth rates peaked in July (coinciding with maximal shoot growth), then declined gradually during late summer; but variability among trees was greater than among water stress treatments. Root/soil respiration maxima of 4.5 μmol CO2/m2 per s occurred in mid June, late July (when new root counts peaked), and the end of August (when root turnover was maximal).
Crop Nutrient Survey Results for Five Vegetable Crops in Dade County, Florida
Authors: Lamberts Mary , Olczyk Teresa , O'Hair Stephen K. , Carranza Juan , Bryan Herbert H. , Hanlon Edward , Hochmuth George
Published: February 2019

A baseline survey was conducted to determine grower fertilizer management practices for five vegetable crops: beans, malanga, potatoes, sweet corn, and squash. This was done in conjunction with a 3-year replicated fertility trial with four vegetable crops (1993–94 through 1995–96) in the Homestead area. Questions included: fertilizer rates and timing, source(s) of fertilizer recommendations, soil and tissue testing, irrigation, changes in practices, summer cover crops, rock plowing, spacing, and type of fertilizer used. Survey results will be presented.
Effect of Benzyladenine (BA) on Fruit Thinning and Carbohydrate Status in Apples
Authors: Yuan Rongcai , Greene Duane W.
Published: February 2019

BA applied at the 10-mm stage at 50 and 100 ppm thinned, increased fruit size, and seed abortion. Net photosynthesis was decreased and dark respiration was increased when temperature following BA application was high (30°C), whereas there was no effect when temperature was lower (20°C). The seed number in abscising fruit was greater in BA-treated fruit than in control fruit. The number of viable seeds in BA-treated fruit was reduced. Tipping the bourse shoot increased fruit set, regardless of BA treatment. BA did not thin fruit with 25 leaves or greater. The translocation of 14C-sorbital from leaves to fruit was promoted by BA application to the fruit, but not when BA was applied to the leaves. The thinning induced by BA will be discussed in relation to available carbohydrate.
Ecophysical Traits and Production of a Semi-domesticated Hot Pepper Genotype (Capsicum frutescens L.) under Different Plastic Mulches
Authors: Nieto-Garibay A. , Troyo-Dieguez E.
Published: February 2019

Diurnal and seasonal water relations and ecophysiological variables (soil humidity, transpiration, evapotranspiration, stomatal resistance, morphological changes, production), matched with some microclimatological variables, were studied in a hot pepper (Capsicum frutescens) experimental plot. Two treatments of plants with plastic mulches were assigned, black and blank-opaque, to compare them with plants without a mulch, established at the Experimental Station of CIBNOR in La Paz Baja California Sur, Mexico. Plants with blank-opaque plastic mulch showed the highest values of flower number, fruit production, leaf area, and canopy-projected area. Also, the biggest evapotranspiration rates were recorded from January to April for plants under the blank-opaque plastic mulch. Soil water content appeared to be a primary determinant factor for production. Soils under the blank-opaque plastic mulch had the biggest water content along the experiment. Plants without any plastic mulch had the lowest availability of soil water, rendered the lowest fruit production, and registered the highest evapotranspiration rates. May and June were the months with the highest air temperature during the experiment. Plants with black plastic mulch had intermediate records among the other two groups. When plants were allowed to face a drought stress, they responded through an osmotic adjustment for maintaining a low water potential, and thus supporting a partial turgor pressure. This adjustment was evident to be coupled with a stomatal regulation in order to minimize the loss of water through the transpiration process. Some drought tolerance strategies as a leaf size reduction were more evident in plants without a mulch.
Net CO2 Assimilation of Apple following Application of Soybean Oil
Authors: Moran R.E. , Deyton D.E. , Sams C.E. , Cummins J. , Pless C.D.
Published: February 2019

Soybean oil can be used as an alternative pesticide for fruit trees. Two separate studies were conducted to determine the effects of oil concentration on leaf phytotoxicity and net CO2 assimilation (ACO2). In one study, concentrations of 0%, 2%, 4%, and 6% soybean oil in water were applied to individual shoots with a hand-held mist bottle. In the second study, 0%, 1.0%, and 1.5% were applied to whole trees with an airblast sprayer. Petroleum oil was applied as a separate treatment. Net CO2 assimilation was measured on single leaves. Oil residue was removed from the leaf with chloroform, dried, and weighed. Chlorosis and defoliation occurred with applications of 4% and 6% soybean oil. No visible phytotoxicity occurred with 2% or less oil. Net CO2 assimilation decreased as the rate of soybean oil increased from 0% to 4% oil, but there was no difference between 4% and 6%. Net CO2 assimilation decreased with increasing oil concentration from 0% to 1.5% and recovered to the rate of the control on day 7. Net CO2 assimilation was negatively related to oil residue. At an equivalent oil residue, there was no difference in ACO2 between petroleum and soybean oil. Below a residue of 0.15 mg·cm–2, foliar phytoxicity did not occur. Reductions in ACO2 were small and did not last longer than 7 days if residues were ≤0.10 mg·cm–2.
Walnut Rootstock Comparison and Own-rooted `Chandler' vs. `Chandler' on Paradox Rootstock
Authors: Hasey Janine K. , Ramos Dave , Micke Warren , Yeager Jim
Published: February 2019

In a comparison of six walnut rootstocks either nursery-grafted or field-grafted to `Chandler' (Juglans regia), the highest-yielding trees after 9 years are on either seedling or clonal Paradox rootstocks. Trees growing on both Paradox rootstocks had higher yield efficiency than trees on the black rootstocks in both 1995 and 1996. Since 1993, relative tree size based on trunk circumference has not changed: southern California black (J. californica), seedling Paradox and northern California black (J. Hindsii) have remained significantly larger than clonal Paradox, Texas (J. microcarpa) or Arizona (J. major) black rootstocks. The smaller size of clonal as compared with seedling Paradox trees might be explained by a delay in field grafting success. Although both northern and southern California black rootstock trees were significantly larger than clonal Paradox trees, they did not differ significantly in yield and had significantly lower yield efficiency in 1996. Clonal Paradox trees have significantly smaller nut size than northern California black rootstock trees that can be explained by its higher yield efficiency. An adjacent trial planted in 1991 compares micropropagated `Chandler' on its own root vs. `Chandler' on seedling Paradox rootstock. In 1995 and 1996, own-rooted `Chandler' had significantly greater trunk circumference, yield, and yield efficiency than did `Chandler' on Paradox rootstock. Many of the trees on Paradox rootstock are growing very poorly compared to the own rooted trees. This could be due to diversity within the Paradox seed source. If own-rooted `Chandler' trees become commercially available, they may have potential in areas where other rootstocks are undesirable because of hypersensitivity to cherry leafroll virus.
Effect of ABA on Growth and Development of Walnut Somatic Embryos
Authors: Huang Bihua , Sutter Ellen G.
Published: February 2019

Development and maturation of somatic embryos is known to be abnormal in many species, particularly woody species. Precocious germination, abnormal cotyledon formation, and shoot development are three problems, among others, that occur during the growth and germination of walnut somatic embryos. Depending on the cultivar or line being cultured, as much as 50% of the embryos in any given culture may be abnormal. Reports in the literature have shown that ABA is useful in enhancing maturation and producing normal germination of somatic embryos of a variety of plant species. In order to overcome the difficulties of producing plants from somatic embryos in walnut, we have incorporated ABA in the nutrient medium in different concentrations and for different periods of time. Globular and cotyledonary embryos were separated and placed on DKW medium containing four different concentrations of ABA, 30, 60, 80, and 120 μM. Morphology, fresh weight, and germination of embryos grown on these different media were recorded. Embryos grown on ABA had lower fresh weight increases than controls, the actual growth depending on both the concentration of ABA present and the length of time the embryos were grown on ABA-containing media. In addition, the percentage of embryos with normal morphology was considerably higher when embryos were grown on ABA. Other factors that were affected by the presence of ABA included the total number of embryos produced and the amount of senescence in the cultures. Germination of embryos was also improved as a result of their being cultured on ABA-containing media.
What Components of Chlorophyll Fluorescence are Related to Storage Scald in Apple?
Authors: Mir N.A. , Wendorf M. , Beaudry R.M.
Published: February 2019

Chlorophyll fluorescence of three cultivars of apple, representing fruits that are considered highly susceptible (`Cortland'), moderate- to highly susceptible (`Red Delicious'), and resistant (`Empire') to superficial scald were studied in relation to scald development during storage. The preclimacteric harvested fruits from each variety were divided into two equal lots, lot one was treated with DPA (1000 ppm) and all the fruits (treated and untreated) were air-stored in separate bins at 0°C for 4 months. Chlorophyll fluorescence parameters, minimal fluorescence (Fo), maximal fluorescence (Fm) and the ratio of (Fm – Fo)/Fm, and various quenching components of variable fluorescence were measured at regular intervals during storage. The maximal level of fluorescence (Fm) at harvest varied between varieties; it was highest in `Empire', followed by `Red Delicious' and `Cortland', respectively. DPA dip treatment seemed to have no influence on chlorophyll fluorescence at harvest. Decline in Fm was found to be related to scald development during storage. The data on fluorescence quenching pattern and kinetics in relation to development of storage scald will be discussed. Changes in radical (a possible cause of apple scald) scavenging system during storage will also be presented.
Reaction of Apple Skin following UV Exposure
Authors: Fonda Harold N. , Fellman John K. , Fan X. , Mattheis J.P.
Published: February 2019

In order to investigate biochemical events occurring at the surface of apple skin, UV light exposure was used to generate a skin-browning reaction in apples. `Fuji' apple fruit that had been kept for 2 months in regular atmosphere storage at 0°C were exposed to short-wave UV light for 24 or 48 hr at 0°C or 23°C. After treatment, skin browning was monitored on fruit returned to 0°C storage or kept at room temperature under laboratory conditions. Fruit exposed to short-wave UV light at 0°C developed skin browning after 2 to 3 days at room temperature, whereas fruit held at 0°C did not show signs of skin browning until 7 days later. Short-wave UV exposure for 24 or 48 hr at 23°C resulted in skin browning that continued to develop on fruit kept at both room temperature and 0°C. When fruit were exposed to short-wave UV light for 72 hr at 0°C, a small amount of skin browning was already apparent. Long-wave UV light exposure for 48 hr had no observable effect on fruit treated at 0°C and then placed at room temperature. Our observations suggest that events that lead to browning are related to dispersion of energy absorbed by the hydrophobic molecules in the skin, a temperature dependent phenomenon.
Effects of Low Oxygen and High Carbon Dioxide Atmospheres on the Chilling Sensitivity of Cucumber Seedlings
Authors: Mangrich Mary E. , Saltveit Mikal E.
Published: February 2019

Crops with origins in tropics and subtropics undergo physiological injury when subjected to nonfreezing temperatures below 12°C. Application of heat and chemical shocks to tissue prior to chilling induces chilling tolerance. This study was undertaken to investigate the effects of low oxygen and high carbon dioxide atmospheres on subsequent chilling tolerance. Cucumber seedlings (Cucumis sativus L., cv. Poinsett 76) with radicles 8 to 12 mm long were subjected to 0% to 21% oxygen and/or 0% to 20% CO2 atmospheres for 0 to 72 hr at 2.5 or 15°C. After chilling, they were placed at 25°C for three additional days. Radicle growth was used to assess chilling injury. Modification of the individual germination plates was necessary to ensure seedling exposure to the desired atmospheres. Chilling injury was reduced by exposure to oxygen levels below 1% and to carbon dioxide levels above 5%. Effects of brief exposures were small in comparison to prolonged exposures during chilling. Seed to seed variability was high and obscured some results. The effects of the various atmospheres were greater with the less vigorous seedlings.
Cooperative Farmer–Scientist Evaluations of Biologically Integrated Soil and Pest Management Practices
Authors: Mitchell J.P. , Goodell P.B. , Prather T.S. , Coviello R.L. , Hartz T.K. , Hembree K.J. , Munk D.S. , May D.M. , Menezes F. , Grimes K. , Diener J. , O'Neill T.
Published: February 2019

In Fall 1995, 12 row crop farmers in conjunction with Univ. of California, NRCS and private agency advisors established the West Side On-Farm Demonstration Project to conduct demonstrations of soil and pest management options aimed at sustained profitability and environmental stewardship in the western San Joaquin Valley of California. Monitoring of soil physical, chemical, and biological properties is done in side-by-side on-farm comparisons of plots amended with organic inputs and unamended plots. Intensive monitoring of beneficial and pest insects is carried out within each comparison block, and the data generated is used to guide pest management decision-making at each site. Yields and soil characteristics of the amended plots did not differ from those of unamended plots after the first year. The on-farm context and the cooperative farmer–scientist interactions of this project facilitate the development of timely and relevant research directions to be pursued beyond the core set of monitoring activities.
Influence of Nodule Development on the Long-term Photosynthetic Response of Beans to Elevated CO2 and Temperature
Authors: Jifon John L. , Wolfe David W.
Published: February 2019

The widely observed reduction in photosynthetic (Pn) capacity following long-term exposure to elevated CO2 is believed to result from an imbalance in source–sink status. We hypothesized that nitrogen fixation in root nodules would provide a strong sink for photosynthate and lead to a sustained positive photosynthetic response to elevated CO2. Bean plants (Phaseolus vulgaris L., cv Redkloud) were grown in poly chambers at one of four combinations of temperature (35/21 or 26/15°C day/night), and CO2 (350 or 700 ppm). Half the plants in each chamber were inoculated with Rhizobium and fertilized with a complete nutrient solution lacking nitrogen; control plants received a similar solution with nitrogen. Total nitrogenase activity (acetylene reduction assay; 8 weeks after planting) of excised whole root systems was stimulated (up to 4-fold) by elevated CO2, but this response was only significant for 26/15°C-grown plants. Inoculated plants also accumulated more biomass (10%) than control plants. Nodule abundance and size were significantly higher in high CO2-grown plants than ambient CO2 plants, but the Pn capacity of inoculated plants was only slightly greater than that of control plants. Averaged across other treatments, high CO2-grown plants accumulated more biomass (42%) and had higher Pn rates (50%) than ambient CO2 plants. Treatment effects on leaf carbohydrate levels and Pn acclimation to CO2 were not consistent. The results suggest that the higher total nodule activity was due to increased nodule number and size in proportion with increased plant size under high CO2, rather than an increase in nitrogenase activity per nodule. It is also evident that plants with symbiotic nitrogen fixation capability can benefit from elevated CO2, even with reduced input of inorganic nitrogen.
Yield and Root Growth Responses of Papaya to Partial Root Volume Irrigation by Drip or Microsprinkler Irrigation Systems
Authors: Marler Thomas E. , Discekici Haluk M.
Published: February 2019

`Tainung 2' papaya seedlings were transplanted on 30 Jan. 1996 and irrigated with one, two, or three drip irrigation lines per row in one study and with 90°, 180°, or 360° microsprinkler spray patterns in a second study to determine the reproductive and vegetative growth responses to irrigation design. Variable irrigation duration was used to supply a homogeneous amount of water to each plant in the drip irrigation study. The trench profile method was used in the drip irrigation study, and a monolith method was used in the microsprinkler study to determine root distribution at the end of the dry season (30 May to 2 June). All fruits were harvested and weighed on 26 Aug. Roots proliferated underneath the drip lines during the dry season, and root concentration on the profile walls was inversely related to the number of drip lines. Root concentration underneath one drip line was 3.7 times greater, underneath two drip lines was 2.3 times greater, and underneath three drip lines was 1.9 times greater than root concentration in the non-irrigated zones. Roots also proliferated in the wetted zones of the microsprinkler spray patterns. Mean fruit weight and total harvested fruit weight did not differ among the irrigation treatments within each study. The results indicate that papaya roots are highly morphoplastic and proliferate in wetted zones under partial root volume irrigation. One drip line per row supplied ample irrigation coverage under the conditions of this study.
Responses of Olive Trees to Low Soil Temperatures
Authors: Pavel E.W. , Fereres E.
Published: February 2019

Responses to low soil temperatures at winter days of high evaporative demand were studied in 20-year-old (fi eld) and 1-year-old potted (controlled conditions) olive (Olea europaea L. cv. Picual) trees in 1996 and 1997. Low soil temperatures apparently affected tree water status as evidenced by low water potentials and stomatal conductance. Low night (2 and 5°C) but ambient day (above 10°C) temperatures did not affect stomatal conductance (gl), leaf (ψl), and xylem (ψx) water potentials of potted olive trees. Tree ψl and ψx decreased when exposed to low night and day temperatures (8°C), but gl was not affected. Water potential of those trees recovered very rapidly when the soil temperature was raised above 10°C at midday. When the trees were exposed to soil temperatures below 8°C for 3 days, ψl, ψx, and gl immediately decreased. After the first day, gl and ψx started to recover while gl was maintained at low levels, thus allowing for tree rehydration. Root hydraulic resistance (rroot)—a major part of whole plant resistance—increased immediately in response to soil temperatures below 10°C relative to that of control trees. The relationship between ψx and rroot indicated that the root system apparently plays a mayor role in the control of tree water status in response to low soil temperatures. During the winter months, olive tree water uptake seems to be primarily limited by low soil temperatures, even though soil water content is normally adequate due to high seasonal rainfall.
Carbohydrate Supply as a Limiting Factor for Citrus Fruit Growth and Productivity
Authors: Goldschmidt Eliezer E.
Published: February 2019

Carbohydrates fulfill several roles in plants; as building stones, as a source of energy, and also, as recently demonstrated, as modulators of gene expression. Primary, photosynthetic production of carbohydrates (as well as their release from tree reserves) is linked with the carbohydrate-consuming processes through complex feedback and feedforward regulatory loops. With horticultural productivity as the goal, maximum resources must be diverted toward reproductive processes. Persistence of viable vegetative structures must be secured, however, to enable the function of tree systems and ensure the tree's potential for future years. Thus, in the carbohydrate resource allocation of fruit trees, a delicate balance must be maintained between the vegetative and reproductive needs. Flowering, fruit set, and fruit enlargement have been identified as three distinct, critical stages within the annual course of yield formation in citrus. While each of these stages has its own, salient developmental features, all require considerable amounts of energy and their occurrence is dependent, at least to some extent, on the availability of carbohydrates. Whereas flower bud differentiation may require only a threshold level of carbohydrates, floral development and anthesis consume large amounts of carbohydrates due to the very large number of flowers per tree and their high rates of respiration. Fruit set is more closely linked to carbohydrate levels. Fruitlet abscission acts as a self-thinning, feedback mechanism to adjust the tree's fruit population to the carbohydrate supply. This mechanism does not operate properly in certain mandarin cultivars, resulting in alternate bearing. The acquisition of fruit size appears to be most directly correlated with the availability of photosynthate. Elimination of alternative sinks by extreme thinning and girdling brings about tremendous increases in fruit size. The fruit's vascular system also expands in response to the increase in photosynthate availability. A dynamic model has been constructed to provide a quantitative analysis of citrus trees' carbon balance during the annual productivity cycle.
Aspects of Carbohydrate Partitioning in Ornamental Geophytes
Authors: Miller William B. , Ranwala Anil P. , Legnani Garry , Langens-Gerrits Merel , de Klerk Geert-Jan , Eckelmann Johannes , Ernst Michael
Published: February 2019

Ornamental geophytes comprise a large and diverse group of plants characterized by underground storage organs that serve the obvious function of reserve storage and subsequent supply during early stages of shoot growth. Relative to many agronomic and horticultural crops, the fundamental physiological bases of carbon metabolism, partitioning, and utilization in geophytes are unclear. One reason is diversity in organ morphology (bulb, corm, tuber, root, rhizome, etc.), storage carbohydrate (starch, fructan, glucomannan, etc.), and growth habit (e.g., synanthous vs. hysteranthous flowering). Knowledge of factors that control accumulation and mobilization of carbohydrate reserves may lead to manipulations that considerably improve the quality and culture of these crops. We are utilizing a variety of techniques and experimental systems to study selected internal and external controls or influences on geophyte carbohydrate metabolism and partitioning. Specific examples to be discussed include bulb storage temperature effects on starch and fructan metabolism in Tulipa, effects of carbon source and dormancy breaking treatments on starch and glucomannan metabolism in in vitro-grown Lilium bulblets, photoperiod control of fructan accumulation in Dahlia seedlings, and biochemical and molecular features of soluble and wall-bound invertases in developing Lilium longiflorum flower buds.
HortBase: A Global Information System for Decision Support
Authors: Green J.L. , Hannaway D. , Matylonek J. , Duncan A. , Liss E. , Starr K.J.
Published: February 2019

HortBase, a global electronic information system to support horticultural decisions in classroom, distance education, life-long learning, and Extension, incorporates three innovative concepts: 1) Three-dimensional-team creation of individual electronic information files (subject, communications, and information science authors collaborating from start-to-fi nish to create the file). Team-creation respects, utilizes and develops professional strengths and resources of each team member. 2) Nation-wide, or even world-wide, distribution of the workload and costs of creation, review, revision, and distribution of the individual electronic information files, rather than redundant individual efforts and expenditures, enables us to do more as a group and to specialize individually. And, 3) National peer review by each file creators' professional society (ASHS, ACE, and ASIS respectively) enhances information quality, continued professional development of the authors, and wider acceptance and use of the information. Capabilities of electronic information systems facilitate, indeed require, this new approach to information development and delivery. For additional information, http://forages.css.orst.edu/HortBase/.
A Genetic Approach for Investigating the Chemistry of Cooked Flavor and Aroma in Sweet Corn
Authors: Juvik John A.
Published: February 2019

Investigating the chemical constituents that determine human preferences for cooked vegetable flavor and aroma is complicated by experimental limitations. Several to many biochemicals interact with each other and with textural properties to influence perception of eating quality. This is particularly true for volatile compounds associated with aroma, where differences in concentration, volatility, reactivity, chemical stability, thresholds of perception, and duration of receptor bonding generate transient stimuli that are integrated into the sensory evaluation of quality. This paper describes methodology that can isolate, identify, and quantify the effect of chemical constituents that influence flavor and aroma using populations segregating for genes controlling eating quality. A F2:3 population derived from a cross between two sweet corn inbreds that differed in kernel characteristics associated with eating quality were assayed for variation in chemical, physical, and sensory characteristics. Because most aromatic constituents of sweet corn are generated during cooking, kernel tissue samples were autoclaved and analyzed by gas chromatography. Panel variation in sample preference were found to be controlled by three overlying factors—taste, texture, and aroma—the relative importance of each being 45.1%, 30.5%, and 24.4%, respectively. DNA marker technology was employed to generate a linkage map of this population that was sufficiently saturated with probes to allow for the identification and mapping of genes controlling each characteristic. This information improves selection methodology in a breeding program aimed to develop germplasm with superior eating quality.
BAS-125, A Promising Vegetative Growth Control Chemical for Bearing Apples
Authors: Unrath C.R.
Published: February 2019

Handgun applications on bearing spur `Red Delicious' evaluated both timing and concentration. At season's end, single 250-ppm applications at petal fall (PF), PF+7, +14 or +21 days reduced growth by 47% to 67%. Concentration of 125, 250, and 375 ppm @ PF+7 were all effective (45% to 55% reduction). Number of pruning cuts, pruning weight, and pruning time were all reduced. Applications at PF+0, +7 and +14 days increased fruit set, and, as a result, fruit weight trended lower. Airblast applications to `Top Red Delicious' applied at PF+3 weeks using 125, 250, and 500 ppm showed good initial growth suppression, but considerable regrowth in August and September. Yet, pruning weight and tree row volume were reduced with no fruit set or quality differences. Multiple, low-rate applications starting at PF on `Granny Smith' were very effective (60-70% reduction). Total application concentrations of 250 ppm were more effective than 500 ppm. The earlier the application sequence was started, the better the growth suppression. Two years of successive 200-ppm applications to the same trees in five separate plots involving three varieties showed an average 32% reduction in year 1 and a 56% reduction in year 2.