bluuebunny/crossref_metadata_2025 huggingface dataset:
BREEDING SITES AND INSECTICIDES EVALUATION TO PROTECT AND INCREASE POPULATION OF COCOA POLLINATORS
Authors: López-Arroyo José I. , Saavedra J. Angel
Published: April 2024

In Mexico, the amount of pollinators in cocoa orchards is being considerably reduced by the use of insecticides and the lack of practices that promote the permanence of pollinator insects. In this study we determined the effect of insecticide sprays and the establishment of breeding sites for pollinators (cocoa husks, decay) banana pseudo stems, and a combination of both) on their population density, pollination level, and cocoa dry bean production. It was observed that mortality rate of pollinators was 73% for both insecticides, Monocrotophos (300 g a.i. ha-1) and Parathion (500 g a.i. ha-1). Even though pollinator insects repopulated the treated area, populations never reached their original levels. Pollination was reduced in 29% to 37% and there was a tendency to decrease dry bean production. Cocoa husks increased pod and dry bean production by 25% and 34%, respectively. The incidence of Phytophthora spp. on the pod did not increase.
FREQUENCY OF COCONUT HARVESTING AND COPRA PRODUCTION
Authors: Dominguez-Castillo Esteban , López-Arroyo José I. , Saavedra J. Angel
Published: April 2024

From the 26 000 ha planted with coconut palm in the state of Tabasco, only 30% is harvested periodically (every four months). In the rest of the area, growers just pick up the fallen coconuts from the ground with the consequence of a high percentage of germinated fruits. This condition drastically reduces copra quality and quantity. The objective of this study was to find the optimal harvesting span to improve copra yield and quality. Results showed that harvesting the coconuts monthly significatively increased copra yield and number of nuts per palm. This represents increases of 123% and 181% in the number of nuts and kg of copra, respectively per palm year-1, as compared with the control. We conclude that more frequent harvests increase the number of nuts and the amount of copra. Conversely, losses caused by fruit germination are reduced.
WATER USE OF GREEN ASH AND NORWAY MAPLE IN TREE SHELTERS DURING ESTABLISHMENT
Authors: Kjelgren Roger , Rupp Larry
Published: April 2024

We investigated how tree shelters affected seedling water use as a fractional coefficient of potential evapotranspiration (ETo) and ability to delay water stress in a nursery setting. A field study investigated water relations of newly planted whips with-and-without shelters irrigated at 100% of ETo or unirrigated. Trees in shelters were shade acclimated based on higher specific leaf area, but in diurnal studies had consistently higher stomatal conductances (gs) than non-sheltered trees. Non-irrigated trees with shelters had higher gs than treatments without shelters. There were no consistent overall differences in water potential (ψ) between irrigation treatments. Predawn ψ of trees in shelters was more negative, but midday ψ was similar to non-sheltered trees regardless of irrigation treatment. A separate study placed shelters over foliage of container-grown whips of green ash and Norway maple and enclosed the roots in plastic to eliminate evaporation. Daily gravimetric water use and ETo was followed for six weeks in 1992. Trees in shelters used substantially less water than control trees. Gravimetric water use normalized to depth units varied from 5-10% as a fraction of ETo. This was less than half that of control trees without shelters. Tree shelters reduced water loss while maintaining high gas exchange, but whether shelters helped tree seedlings to delay water stress during establishment was inconclusive from these data.
INTEGRATING AQUACULTURE INTO NURSERY AND TURF FARMS TO IMPROVE WATER AND NUTRIENT USE
Authors: Khan Masud A. , Berghage R.D. , McCrimmon J.N.
Published: April 2024

Multiple use of water through integrating aquaculture and irrigated crop production could minimize the cost of rearing fish and irrigating crops. Aquaculture effluent was tested for irrigation of four turfgrass species and Elderica pine seedlings. Plants were irrigated with fish effluent or city water, with or without supplemental fertilization from Osmocote® or Milorganite®. Turfgrass irrigated with effluent gained more biomass and had better color than grass watered with city water. Treatment with supplemental fertilizer resulted in significantly more biomass gain than in untreated turf. A Minolta CR-200 chroma meter was used to determine L, a, b color coordinates and leaf chlorophyll was extracted in DMF (dimethylformamide) and measured with a spectrophotometer. Color coordinate data were correlated with leaf clorophyll content and both were correlated with biomass gain.
OVERHEAD PULSE IRRIGATION REDUCES IRRIGATION RUNOFF AND CONTAINER LEACHATE
Authors: Fare D.C. , Gilliam C.H. , Keever G.K.
Published: April 2024

Overhead pulse irrigation was evaluated as an alternative irrigation practice to reduce container leachate and irrigation runoff. Six irrigation treatments evaluated included 1.25 cm volume applied at 1, 2, and 3 pulses and 0.63 cm volume applied at 1, 2, and 3 pulses with a 1 hr delay between pulses. Irrigation runoff and container leachate were about 50% less in the 0.63 cm treatments compared to the 1.25 cm treatments. There was a 10-14% reduction in irrigation runoff and 29-32% reduction in container leachate when comparisons were made between the 1 pulse and 3 pulse treatments regardless of the irrigation volume applied. Shoot and root growth of Compacta holly were similar among all treatments.
INTERMITTENT SPRINKLER IRRIGATION INCREASES IRRIGATION APPLICATION EFFICIENCY
Authors: Karam Nabila S. , Niemiera Alexander X.
Published: April 2024

Experiments were conducted to determine if applying a container-grown plant's daily water allotment in multiple applications (intermittently) increased application efficiency relative to the allotment applied in a single application (continuous). Water was applied (simulated overhead sprinkler system) to marigold plants in a pine bark substrate. Time interval between intermittent applications and water movement in the substrate were investigated. Application efficiency was greater when the water allotment was applied intermittently compared to a single application. Efficiency was also greater when the interval between applications was increased from one to two h. Sectioning substrate into top, middle, and bottom thirds showed that the bottom layer of the intermittent treatment contained more water than the bottom layer for the continuous treatment. There were no differences in water content in the top and middle layers between the two treatments.
DESIGN AND OPERATION OF AN AUTOMATED CAPILLARY IRRIGATION SYSTEM FOR PRODUCTION OF CONTAINERIZED NURSERY PLANTS.
Authors: Hicklenton Peter R. , Cairns Kenneth G.
Published: April 2024

Capillary irrigation uses less water than most other methoes, and effectively reduces the quantity of fertilizer leaching from nursery containers. We have developed a sand bed system with automatic control of bed hydration using inexpensive and readily available analog hardware. Water supply to the sand bed (via irrigation drip hose) is controlled by a bridge-type temperature controller associated with two stainless steel mesh sensors embedded in the sand. Growth, quality and nutrient status of capillary (CI) or drip-irrigated (DI) Juniperus horizontalis `Plumosa Compacta'(Andorra juniper) and Euonymus fortunei `Coloratus' were compared in 2 consecutive growing seasons. At the end of the second year CI Juniper and Euonymus plants were 23% and 37% larger, respectively, than their DI counterparts. Foliar N did not differ between irrigation regimes in Juniper, but both P and K levels were higher in CI plants; foliar N, P, and K, were consistently higher in CI Euonymus.
CONSUMER ACCEPTANCE OF SPECIALTY CUT FLOWERS
Authors: Gast Karen , Stevens Alan
Published: April 2024

Specialty cut flowers or “old fashion garden flowers” include all decorative plant materials except roses, mums and carnations. These were commonly found in the trade over fifty years ago, but lost favor because of short vase lives and a centralization of flower production in the country and a movement of it overseas. We are now seeing a resurgence of specialty cut flower production but have a generation or two of consumers who are unfamiliar with them. The purpose of this study was to acquaint consumers with various specialty cut flowers and evaluate their acceptance. Small desk size bouquets and large bouquets were evaluated, which was done once a week for four weeks. Each week the shape and form of the bouquets changed as did the plant material. Over ninety percent of the respondents said they would include specialty cut flowers in their next flower purchases but were non committal about a preference of them over traditional cut flowers. The large bouquets seemed to produce the greatest impact but both sizes seemed to improve the work environment.
EFFECT OF LOW TEMPERATURES ON FRUIT QUALITY IN MELON (CUCUMIS MELO L.)
Authors: Rosengartner Yvonne , Bar-Zvi Dudy , Mendlinger Samuel
Published: April 2024

Within a program determining the response of melon plants when grown at suboptimal cold temperatures, fruit quality was examined in 20 cultigens grown under two temperature regimes. The cultigens included open pollinated and hybrid cantaloupes and honey dews. The two temperature regimes were: (i) heated greenhouse, at minimum and maximum temperatures close to commercial cultivation requirements, and (ii) unheated greenhouse, at a temperature 7-8°C lower than the former, representing a major cold stress. The parameters examined included fruit appearance and marketability (weight, size, netting) as well as fruit constituents (sucrose, glucose, reducing sugars, TSS, pH, EC, titratable acidity). Cold stress was found to improve some parameters, but impair others. The low temperatures significantly reduced fruit weight and size, but increased fruit number per plant, sucrose and TSS in most but not all cultigens. Significant interaction was found between the temperature regimes and cultigens in these parameters. The results strongly indicate that genetic variation exists in melons for response to low temperature, and therefore that potential for breeding melons for cold stress is present.
DEVELOPMENT OF A CULTURAL SYSTEM FOR COMPACT GROWTH HABIT FRESH-MARKET TOMATO LINES.
Authors: Kemble Joseph M. , Davis Jeanine M. , Gardner Randolph G.
Published: April 2024

Staked, fresh-market tomato production in the southeastern US is intensive and involves a high level of inputs. Labor costs, for the hand operations of staking, pruning and tying, constitute a large portion of these inputs. Compact growth habit tomato lines are being developed to replace standard determinate cultivars. Plants with this growth habit do not require pruning, staking or tying, and when grown in double-rows on plastic-covered beds, produce high early-season yields. Since a large number of transplants are required for double-row plantings, the use of high-density planter flats was studied. The influence of planter flat cell volumes (ranging from 3.3 cm3 [highest plant density] to 80 cm3 [lowest plant density]) and transplant age (4- and 5-weeks-old) on flowering and early marketable yields was examined. In 1991 and 1992, highest early marketable yields (19,171 kg/ha and 23,743 kg/ha, respectively) were obtained with the oldest transplants produced in the 80 cm3 cells. With 37 cm3 cells, however, larger quantities of transplants could be produced with a minimal delay in maturity and loss in yields. A complete cultural system, from transplant production to harvest, is proposed for use of these compact growth habit tomato lines for early-season fresh-market tomato production.
EVALUATION OF CHINESE RASPBERRY SPECIES IN NORTH CAROLINA
Authors: Ballington James R.
Published: April 2024

Three raspberry species, Rubus corchorifolius, R. hirsutus and R. innominatus, from southern China were evaluated for plant and fruit characteristics at Jackson Springs, N.C., in 1991 and 1992. Plants of all three species were well adapted and could potentially become naturalized if birds or mammals develop a taste for the fruit. Rubus corchorifolius stems were fully erect and primocanes were often 2.5 m tall by June 1, 1992. Rubus hirsutus produced profuse shoots covering up to 2 m2 during the first growing season. Stems were fully erect and generally 0.2-0.3 m. tall. Rubus innominatus was very vigorous with an arching growth habit similar to black raspberry. Rubus corchorifolius bloomed in February and produced very little fruit. Berries were small and yellow with a distinctive sweet and sour flavor. Rubus hirsutus bloomed in early April in 1991 and February in 1992. Fruits were generally large, bright red, with a resinous aftertaste. Rubus innominatus bloomed in late April in 1991 and May in 1992. Fruits occurred in large clusters, were red to reddish-black, medium to large in size, and similar to R. parvifolius in quality. Rubus innominatus appeared very promising as a parent in raspberry improvement for the southeastern US.
UNIQUE ORGANIC ACID PARTITIONING OF RABBITEYE VERSUS HIGHBUSH BLUEBERRIES
Authors: Ehlenfeldt Mark K. , Meredith Filmore I.
Published: April 2024

The fruit of 6 highbush cultivars and 8 rabbiteye cultivars and selections were evaluated by HPLC for levels and partitioning of the commonly found organic acids, citric, malic, succinic, and quinic. The two cultivar groups possessed distinctive acid partitioning patterns which could unambiguously separate rabbiteye and highbush clones. Highbush material was characterized by high citric acid, with percentages averaging 75% (range 38 to 90%), and succinic acid the next most plentiful acid, averaging 17%. In contrast, rabbiteye cultivars averaged 10% citric acid, and no clone had more than 22%. Succinic acid and malic acid were found in greater quantities than in highbush, averaging 50% and 34% respectively. Analysis of the fruit of 7 albino highbush selections exhibited a profile similar to standard highbush material, but with citric acid reduced to an average of 50%, and the proportional increase in other acids distributed between succinic and quinic acids.
AVAILABILITY AND HERITABILITY OF SALT TOLERANCE IN RABBITEYE BLUEBERRY
Authors: Gupton Creighton L. , Spiers James M.
Published: April 2024

To assess the variability and heritability of salt tolerance in current rabbiteye blueberry (Vaccinium ashei) germplasm, about 30 plants from each of 15 crosses involving 8 parents were grown in sand culture. All plants were fertilized five days per week with a solution containing essential micro-and macronutrients but having an excess (250 ppm) Na level. After nine weeks, each plant was rated for vigor and chlorosis, dry weights of roots and shoots were recorded, and Na content of the roots and leaves were determined. The regression of progeny means on mid-parent means for leaf Na content produced a regression coefficient of 0.30, an estimate of heritability. There appeared to be little variability for Na content in the leaves of this germplasm so the moderate level of heritability would not be expected to produce much change in leaf Na by selection. Furthermore, there was no correlation between leaf Na content and either plant weight or rating which would facilitate selection of plants with low salt content in the leaves. variability existed for plant response to excess Na (plant rating) but heritability of the plant rating was estimated to be zero.
WATER USE EFFICIENCY OF FOUR GRAPEVINE VARIETIES UNDER MEXICAN DESSERT CONDITIONS.
Authors: Robles-Contreras Fabián , Fimbres-Fontes Adán , Martínez-Díaz Gerardo , Grijalva-Contreras Raúl Leonel
Published: April 2024

The main limitant of crop production in the agricultural area of Caborca, Sonora, is water availability since evaporation is greater than rainfall (2250 and 200 mm/yr respectively). Under this conditions is important to make a rational use of this resourse. In order to determine water consumptive use and water efficiency of Thompson Seedless, Perlette, Carignane and Tinta Madeira several experiments were conducted in 1983, 1984 and 1985. In Thompson Seedless various crops coefficients were applied in three phenological strages and the other varieties were exposed to the some irrigation intensities. The water consumptive use was 57-8, 51.1, 59.7 and 59.7 cm for Thompson Seedless, Perlette, Carignane and Tinta Madeira respectively and the water use efficiency (kg/m3 water/ha) was 4.31, 3.92, 3.52 and 3.01 for the some cultivars.
TIMING AND CONCENTRATION OF GIBBERELLIC ACID APPLICATIONS FOR BERRY THINNING AND SIZING OF `VANESSA' SEEDLESS GRAPES.
Authors: Zabadal Thomas J. , Bordelon Bruce P.
Published: April 2024

Timing and concentration of GA applications were evaluated for berry thinning and sizing on `Vanessa'. Mid-bloom applications at 0, 5, 10, 15, 20 and 30 ppm GA were tested for berry thinning. Post-bloom applications of 0, 25 and 50 ppm GA at 7, 12, 16 and 21 days past mid-bloom were tested for berry sizing. None of the mid-bloom (thinning) treatments significantly reduced the number of berries per cluster or cluster compactness. Mid-bloom applications at 15, 20 and 30 ppm GA significantly increased berry weight. Post-bloom (berry sizing) treatments significantly increased berry weight with each increase in GA concentration for each time of application. The number of berries per cluster was significantly increased by sizing sprays at 7 and 12 days, but not at 16 or 21 days past mid-bloom. Cluster weight was significantly increased by 25 and 50 ppm GA applied at 7, 12 and 16 days past mid-bloom. All post-bloom applications significantly reduced the number and weight of shot berries.
EFFECTS OF TRELLIS FORM ON RADIATION INTERCEPTION WATER USE AND PHOTOSYNTHESIS IN GRAPEVINES
Authors: Al-hazmi Manea H. , Lakso Alan N. , Denning Steven S.
Published: April 2024

Manipulating radiation interception by using horizontal and vertical trellis forms was tested for effects on water loss and photosynthesis on sunny days. Water loss from 15 potted Pinot Noir vines of each form was estimated by weighing the vines at two hour intervals during the day. Radiation interception for vines and gas exchange of individual exposed leaves was measured over the day to evaluate the leaf activity patterns in relation to exposure patterns. Similarly, diurnal whole vine photosynthesis measurements were taken by using clear plastic “balloon” whole vine chambers. The horizontal form had higher radiation interception than the vertical form during the day, resulting in higher water loss from the horizontal form. Under N-S orientation, the horizontal form showed a gradual decrease in exposed leaf and whole vine photosynthesis starting in late-morning while the vertical form had a more uniform pattern over the day. The long periods of leaf exposure of horizontal canopies appears to induce a photosynthetic decline that also reduces afternoon transpiration. Vertical forms have two populations of leaves that are exposed for shorter periods, thus less photosynthetic decline occurs. Vertical trellis forms may have potential for improving water use efficiencies in arid regions with high radiation.
SEASONAL VARIATION IN THE ACTIVITY OF NITROGEN ASSIMILATION ENZYMES FROM STRAWBERRY ROOTS
Authors: Archbold Douglas D.
Published: April 2024

Significant seasonal fluctuations in the soluble and insoluble reduced N pools of strawberry roots and crowns suggest seasonal alterations in the activities of the enzymes responsible for nitrogen assimilation. The activities of glutamine synthetase (GS), NADH- and ferredoxin-glutamate synthase (NADH- and Fd-GOGAT), and glutamate dehydrogenase (GDH) were assayed from extracts of `Allstar' strawberry roots sampled at intervals over 12 months from matted row beds. GS activity was high during late winter and declined 16-fold by the summer and fall. Although Fd-GOGAT activity was not detected, NADH-GOGAT activity exhibited over 5-fold higher levels during bloom and fruiting than at other times of the year. GDH activity fluctuated over 8-fold during the year with the highest levels occurring during the spring growth flush and after bed renovation. The seasonal changes in enzyme activities corresponded to significant events in plant development and indicate involvement of these enzymes in N assimilation and cycling in strawberry.
N, CA, AND MG FERTILIZATION AFFECTS GROWTH AND LEAF ELEMENTAL CONTENT OF `DORMANRED' RASPBERRY
Authors: Spiers James M.
Published: April 2024

`Dormanred' raspberry (Rubus species) plants grown in sand culture were subjected to varying concentrations of N, Ca and Mg over a two-year period. Increasing nitrogen fertilization resulted in linear reductions in leaf Ca, K, Zn, Fe, and Mn, but did not affect leaf Mg. Leaf Ca and K increased linearly with Ca fertilization, but applied Ca had an antagonistic influence on leaf Mg. Magnesium fertilization had a positive influence on leaf Mg but negatively affected leaf K, Ca and Mn. Plant growth was negatively correlated with Ca fertilization, leaf Ca, and leaf K, but had a positive correlation with leaf Mg and Mn. Nitrogen fertilization increased plant growth up to the mid-level of applied N, but additional N reduced plant growth.
DEFOLIATION AND GIRDLING EFFECTS ON CHILLING ACCUMULATION IN RABB1TEYE BLUEBERRY
Authors: Darnell Rebecca L.
Published: April 2024

Dormant two-year old `Bonita' rabbiteye blueberries were subjected to the following treatments: 1) no defoliation, 2) one-half of the canes on a plant defoliated, and 3) complete defoliation. After 300 h at 7C, plants were brought into the greenhouse and vegetative budbreak was assessed. Completely defoliated plants exhibited rapid, extensive budbreak, averaging 70 budbreaks/plant. Plants or individual canes that retained their leaves during chilling averaged 25 budbreaks/plant. Budbreak on defoliated canes of partially defoliated plants (treatment 2) was drastically reduced compared to whole plant defoliation, averaging 30 budbreaks/plant. In a second study, plants were partially defoliated, as in treatment 2 above. The foliated canes remaining on each plant were then either girdled or non-girdled. After 300 h chilling, vegetative budbreak was assessed. Budbreak on defoliated canes of plants that had non-girdled foliated canes was low, averaging 15 budbreaks/plant. Budbreak on defoliated canes of plants that had girdled foliated canes was significantly higher, averaging 35 budbreaks/plant. These results suggest that chilling is inhibited by leaves, and this “inhibition” is phloem translocatable from leaves to buds on other canes, thus inhibiting budbreak on those canes.
SUPPLEMENTAL IRRADIANCE DURING PRIMULA SEEDLING DEVELOPMENT
Authors: Karlsson Meriam G. , Hanscom Jan T.
Published: April 2024

Seedlings of Primula malacoides Franch `Prima Carmine Red' and Primula vulgaris Huds.`Danova Lemon Yellow' received supplemental irradiance from high pressure sodium lamps for 2 weeks initiated at germination, 14 days after germination or 28 days after germination. The plants were grown at 15 ± 3C, 16 hours photoperiod and except during treatment, an average photosynthetic photon flux of 100 μmol·s-1m-2 (5.8 mol· day-1m-2). The irradiance levels during treatment were 200 or 300 μmol·s-1m-2 (11.5 or 17.3 mol·day-1m-2). There were no significant effects of supplemental irradiance on rate of flowering for P. malacoides, although the leaf number on the main shoot increased from 22 ± 4 leaves for control plants to 30 ± 3 leaves for plants receiving 300 μmol· s-1m-2. Flowering of P. malacoides averaged 100 ± 4 days from germination. Two weeks of 300 μmol· s-1m-2 initiated 4 weeks after germination resulted in an average plant dry weight of 0.56 ± 0.07 g compared to an average 0.39 ± 0.05 g for plants continuously grown at 100 μmol· s-1m-2.
PRECONDITIONING PLUG-GROWN GERANIUMS WITH TEMPERATURE AND FERTILITY BEFORE STORAGE.
Authors: Kaczperski Mark P. , Armitage Allan M.
Published: April 2024

Seedlings of Pelargonium × hortorum `Scarlet Elite' were grown to transplantable size in #406 plug trays. Seedlings were preconditioned for storage by applying 0, 75, 150 or 300 mg l-1 nitrogen using a 15-16-17 fertilizer or growing the seedlings at 10, 15 or 20 C, for 14 days immediately preceding storage. After preconditioning, seedlings were stored in the dark at 5 C for 0, 7, 14 or 21 days, and then transplanted to 10 cm pots and grown to flower under greenhouse conditions. Unstored seedlings flowered fastest when the highest fertility level was maintained during the preconditioning stage. However, fastest flowering of stored seedlings occurred when preconditioned with 150 mg l-1 N. Plants preconditioned at the highest N level had the highest mortality rates during storage. Preconditioning seedlings at 10 or 15 C delayed flowering compared to seedlings grown at 20 C.
FLOWERING COMPARISONS OF THREE POPULAR ROSE (ROSA HYBRIDA L.) CULTIVARS
Authors: Story Virginia S. , Hopper Douglas A. , Meinke Troy T.
Published: April 2024

Two-year-old Rosa hybrida L. `Royalty', `Emblem', and `Samantha' plants were pinched 20 Oct. and 28 Dec. 1992 for Christmas and Valentine's Day crops. Two greenhouses received ambient CO2 and two were enriched to 1200 ppm CO2 when vents were closed. All temperature set points were 22C/17C day/night. At 10 and 25 days after pinch, and at flowering, 5 shoots from each bench location were destructively sampled for leaf (node) number, stem diameter, stem length, and fresh weights of stem, leaves, and flower bud. Time to visible bud and to flowering from pinch also were recorded.

Analysis of variance for the 1992 Christmas crop did not find significant differences for flowering times, but trends in response were evident. The 3 cultivars had mean flowering times of: `Royalty', 51.3 days; `Emblem', 52.3 days; and `Samantha', 54.0 days. Enrichment with CO2 showed a trend for decreased average flowering times for all 3 cultivars. Results from the 1993 Valentine's Day crop will also be presented.
INTERACTION BETWEEN SHIPPING AND ROOTING TEMPERATURE ON VERNALIZATION OF LILIUM LONGIFLORUM THUNB.
Authors: Erwin John E. , Engelen-Eigles Gerard
Published: April 2024

Lilium longiflorum Thunb. cv `Nellie White' bulbs (17.7-20.3 cm circumference) were received immediately after harvesting from the field. Bulbs were placed in moist sphagnum peat in plastic bags to simulate a shipping crate and were placed in controlled environment chambers maintained at 10, 20 or 30C for 2 wks. Bulbs were then planted in soilless medium in a 15.2 cm pot and were placed into controlled environment chambers maintained at 10, 20, or 30C for root development for 2 weeks to yield 9 different shipping/rooting treatments. Potted bulbs were then vernalized for 6 weeks at 6C. Bulbs were then placed in a glasshouse maintained at 18 ± 2C under natural daylight. Data were collected on date of emergence, visible bud, and anthesis. Leaf and flower number were also collected. Time to emergence and visible bud increased as the shipping temperature which bulbs were exposed to increased. Bulbs which were exposed to 10C shipping and/or rooting environment had reduced leaf and flower number. Exposure of bulbs to 30C during the shipping treatment resulted in plants which appeared undercooled and/or unvernalized.
GROWING TEMPERATURE OPTIMA OF FOUR ORNAMENTAL GRASSES
Authors: Lavis-Ham C. , Albrecht M.L.
Published: April 2024

Growth chamber studies were conducted to determine the optimum temperature for growth of four ornamental grasses: Imperata cylindrica `Red Baron', Carex morrowii `Aurea Variegata', Pennisetum alopecuroides `Hameln', and Schizachyrium scoparium. Plants were grown in chambers using temperatures of 15, 20, 25, and 30C. Measurements of fresh and dry shoot/root weights, tiller number, leaf area and plant height were taken after 10 weeks. Schizachyrium and Imperata exhibited an increase in growth as temperature increased, with 30C appearing to be the optimum for both species. Pennisetum showed positive gains in size and quality at 20 and 25C. Carex showed ideal growth at 20C.

In addition to the chamber study, measurement of chlorophyll fluorescence from intact leaves was used to identify temperature optima. Preliminary results suggest the fluorescence technique may not be conclusive when using species with low photosynthetic productivity.
USING COMPUTER SIMULATION TO UNDERSTAND CONTAINER MEDIA
Authors: Burés Silvia , Pokorny Franklin A. , Ferrenberg Alan M. , Landau David P.
Published: April 2024

Monte Carlo simulation has proven useful to understand container media properties. Although use of container media in horticulture is widespread, their physical properties are often misunderstood. Container media usually have larger external pores than natural soils, and the components from which they are formulated may have internal porosity that often accounts for half the total porosity. Traditional laboratory methods have provided limited insight into container media phenomena because of the difficulty in distinguishing between internal and external pores. By means of computer simulation we have characterized external porosity and pore size of container media. We have also been able to study volume shrinkage upon mixing components with different particle sizes. Pore size can be correlated with water retention characteristics, and size of external pores is related to the sizes of the particles that are mixed. With Monte Carlo simulation one can mix different particle sizes in different proportions, thus determining the relationships between pores and particle sizes.
INHIBITION OF GROWTH OF CALADIUM BY HIGH TEMPERATURE
Authors: Harbaugh Brent K. , Evans Michael R.
Published: April 2024

Caladium × hortulanum Birdsey `Candidum' tubers were exposed to 26, 38, 43 and 48C for 1, 2 and 3 days. Tubers were then forced in a glass-glazed greenhouse. Tubers exposed to 48C for 1 and 2 days required significantly longer to emerge than all other temperature treatments, while tubers exposed to 48C for 3 days failed to emerge. After 4 weeks of growth, exposure of tubers to 43C for 2 and 3 days and 48C for all time periods resulted in plants with reduced shoot fresh weights and fewer leaves with a width greater than 15 cm. After roots developed to the edge of the pot and shoots emerged (10 days after potting), potted tubers were exposed to 43C for 0, 4, 8, 12, 16, 20 and 24 hours per day for 1, 3 and 5 days. Potted tubers exposed to 43C for 8 or more hours per day for 3 days and 12 hours or more for 5 days were significantly delayed in emergence. Only 33% of potted tubers exposed to 43C for 24 hours per day for 5 days emerged. Exposure to 43C for 1 and 3 days resulted in increased shoot fresh weights for exposures up to 12 hours per day. As the exposure time per day increased, shoot fresh weights decreased. Exposure of potted tubers to 43C for 16 hours or more per day for 3 days reduced plant height and the number of leaves with a width greater than 15cm. Regardless of the number of hours of exposure per day, potted tubers exposed to 43C for 5 days had reduced shoot fresh weights and fewer leaves with a width greater than 15cm as compared to unexposed potted tubers. As the number of hours of exposure per day increased, shoot fresh weight and the number of leaves with a width greater than 15cm decreased.
MATURITY AND STORAGE EFFECTS ON POSTHARVEST ONION QUALITY
Authors: Wall Marisa M. , Corgan Joe N.
Published: April 2024

A two-year field study was conducted to evaluate the effects of maturity and storage on fresh market onion quality. Four short day onion cultivars (NuMex BR1, NuMex Sunlite, NuMex Starlite and Buffalo) were seeded in early October of both years. Bulbs were harvested at 5 different times, with harvest #1 when 20% of the bulbs in a plot had mature necks. The second harvest was when 80% of the bulbs in a plot had matured. Harvests #3, #4 and #5 were at 5, 10 or 15 days after the second harvest date. After curing, bulb firmness and weight, and the incidence of bulb diseases were evaluated for the 5 harvest dates. Bulbs were re-evaluated after 10 and 20 days storage in a shed under ambient conditions. Average bulb weight increased from 181.6g to 274.1g as harvest was delayed. Bulb firmness decreased from 56N to 52N. Percent diseased bulbs increased for all cultivars as harvest was delayed in 1991, while in 1992 this trend was not observed. In storage, average bulb weight and firmness decreased, while the incidence of bulb diseases increased greatly regardless of harvest date. Storage diseases were primarily Aspergillus niger and bacterial soft rot.
DOES SILVER INHIBIT ETHYLENE ACTION THROUGH EFFECTS ON APOPLASTIC ENZYMES?
Authors: Curran Joseph E. , Knee Michael
Published: April 2024

The mechanism by which silver salts interfere with ethylene action in plants is unknown. Prior research indicates that silver acts outside the plasma membrane. We tested a number of plant apoplastic enzymes for inhibition by silver salts. Tomato (Lycopersicon esculentum) fruit pericarp cell wall enzymes, phosphatase, cellulase, peroxidase and polygalacturonase were not inhibited by 100μM AgNO3. At 100μM AgNO3 pectin methyl esterase was inhibited 24.9% and invertase 68.6%; β-galactosidase was inhibited 98.0% by 10μM AgNO3. β-Galactosidase and invertase were not inhibited by silver thiosulfate (STS) at concentrations commonly used to inhibit ethylene action. In other experiments, pea (Pisum sativum) sub-apical hooks were excised and tested in vivo for NADH-ferricyanide oxidoreductase activity. This enzyme was inhibited by 1μM AgNO3 and showed some inhibition by STS. These results indicate that the tomato cell wall enzymes tested are not involved in silver inhibition of plant responses to ethylene. The possible involvement of the oxidoreductase and other plasma membrane enzymes in ethylene action are being considered.
CARBOHYDRATE STATUS AND POSTHARVEST QUALITY OF MINIATURE ROSES GROWN UNDER CARBON DIOXIDE ENRICHMENT
Authors: Rajapakse N. C. , Clark D. G. , Kelly J. W.
Published: April 2024

The role of CO2 enrichment on carbohydrate status and postharvest quality of miniature roses was investigated. Plants were grown in 350, 700 or 1050 μl·liter-1 CO2 until they reached flowering stage. Stomatal resistance was increased (≈25%) by 700 or 1050 compared to 350 μl·liter-1 CO2. Both 700 and 1050 μl·liter-1 CO2 increased leaf sucrose but had no effect on stem sucrose concentration. However, the increase in leaf sucrose content was small (≈10%). CO2 enrichment did not affect leaf glucose but increased stem glucose concentration. Leaf and stem fructose was higher in 350 than in 700 or 1050 μl·liter-1 CO2. Leaf and stem starch concentration increased over three-fold as CO2 increased from 350 to 700 μl·liter-1. Both 700 and 1050 μl·liter-1 CO2 reduced sucrose:starch ratio by 73% compared to low CO2 level. CO2 enrichment did not affect the over all visual quality or percentage leaf yellowing after 5 days in the interior environment of plants stored at 4 or 16C. Plants stored at 16C showed about three-fold increase in leaf yellowing compared to that of plants stored at 4C under any CO2 treatment. Although CO2 enrichment increased the carbohydrate status of the plants, our results do not support the hypothesis that increase in carbohydrate status play a role in improved postharvest quality and reduction in leaf yellowing of miniature roses.
RESPONSE DIFFERENCES BETWEEN AVOCADO AND MANGO FRUIT EXPOSED TO INSECTICIDAL MODIFIED ATMOSPHERE
Authors: Domínguez Marisela Rivera , Yahia Elhadi M. , Moreno Luz Vázquez
Published: April 2024

Atmospheres with very low levels of O2 (≤0.5%) and/or very high levels of CO2 (≥50%) were reported to be insecticidal, and thus have a potential for postharvest insect control in horticultural crops. Our previous studies have shown that avocado fruit (Persea americana Mill cv. Hass) is very sensitive, while mango fruit (Mangifera indica L. cv Keitt) is very tolerant to these extreme atmospheres. The objective of this study was to investigate the differences in responses of the two fruits to insecticidal atmospheres. Fruits were evaluated after storage in a static modified atmosphere (MA) of < 0.4% O2 and up to 80% CO2 for 0, 1, 2, and 3 days at 20°C. Avocado produced intensive fermentative odor in the second day of storage while mango did not present any throughout the 3 days. Pyruvate concentration was very low in both fruits. Lactate concentration was higher in avocado and has accumulated more in MA than in air stored fruits. Avocado had higher activity of alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH), but less activity of pyruvate decarboxylase (PDC) than mango. There were no major differences in the specific activity of ADH, PDC, and LDH between air and MA stored fruits. Avocado and mango fruit differ in their biochemical responses to insecticidal (extreme) atmosphere. The basis of these differences in relation to fruit sensitivity/tolerance will be discussed.
IN VITRO SELECTION AND MOLECULAR CHARACTERIZATION OF MELOIDOGYNE INCOGNITA-TOLERANT PEACH SOMACLONES
Authors: Hashmi G. , Krusberg L.R , Meyer R. , Huettel R. N. , Hammerschlag F. A.
Published: April 2024

Peach regenerants 156-1, 156-7, 156-11, 156-12 and 30-1, 30-2, 30-4, 30-6, 30-7 and 30-8 were obtained from immature embryo #156 from highly susceptible cv. Sunhigh and from immature embryo #30 from moderately tolerant cv. Redhaven, respectively. Significantly higher numbers of nematodes developed on 156-7 and `Sunhigh' compared with 156-1, 156-11, and 156-12, whereas no significant differences in nematode development were observed among `Redhaven' regenerants. RAPD primers were used with the polymerase chain reaction (PCR) to identify somaclonal variation at the molecular level. Sixty RAPD primers (10-mers) were screened for markers. Genomic DNA was isolated from regenerants 156-1, 156-7, 156-11, 156-12, and cv. Sunhigh using the CTAB method. DNA was amplified with each of the sixty primers. Although 35 primers produced results with scoreable and consistent bands, RAPD polymorphism was observed with only 10 of the primers.
RAPD MOLECULAR MARKERS IN WATERMELON
Authors: Zhang X. P. , Rhodes B. B. , Skorupska H.
Published: April 2024

We examined the RAPD (random amplified polymorphic DNA) technique in our efforts toward mapping the watermelon genome. Three cultigens: Dixielee, G17AB and New Hampshire Midget (NHM), and the primitive watermelon PI 296341 and the hybrid NHM × PI 296341 were tested for polymorphic RAPD markers with 53 10-mer primers. Among total of 159 readable bands, 89 (62.3%) of the bands were polymorphic among the four accessions and 82 (51.6%) of the bands were polymorphic between NHM and PI 296341, but only 16 (10.1%) were polymorphic within the three cultigens. Results of cluster analysis based on the RAPD data were correlated with agronomic characters. The watermelon genome size was estimated by flow cytometer analysis to be relatively small, ca. 0.98 pg. The large number of polymorphic loci and the relatively small genome will enable us to develop a high density linkage map. Cosegregation analysis is under way to establish linkage relationships between the RAPD markers and estimate recombination distances between agronomic traits and molecular markers.
USE OF RANDOM AMPLIFIED POLYMORPHIC DNA VARIETIES (RAPD) TO DISTINGUISH SHORT-DAY GRANO-TYPE ONION VARIETIES
Authors: Roxas Virginia P. , Peffley Ellen B.
Published: April 2024

Nineteen random primers yielded 36 PCR-amplified products of Allium cepa DNA. RAPD profiles of each of 12 short-day grano-type onion varieties used as breeding lines or grown commercially in Texas and Southern U.S. were compared. Several PCR products were unique among the varieties and can be used to differentiate among the onion cultivars investigated. A phenogram of the varieties based on the co-occurrences of the PCR products was derived.
CLONAL SELECTION OF COLD-TOLERANT LINES IN GRAPE CELL CULTURE
Authors: Mingpeng Zhang , Rajaskekar C.B.
Published: April 2024

Suspension cultures of grape hybrids (Vitis spp.) were used to select cold tolerant cell lines. The cultured cells were subjected to selection pressures by cooling at 2° C/h to various temperatures below the average lethal temperature (LT50) of the cell population. The cold tolerant lines were selected based on the distribution of lethal temperatures in the population. The small fractions of cells which were more cold tolerant than the LT50 of the population were enriched by many selection cycles. After two selection cycles, the cold tolerant lines of all three cultivars survived -9 and -9.6°C (LT50), whereas the control population survived between -2.5 and -3.2°C. The increased cold tolerance in selected lines was due to shifts in the frequency and distribution of lethal cell injury in the selected population as compared to the unselected control.
SOLUBLE SUGARS AND WINTER HARDINESS IN FLOWER BUDS OF FORSYTHIA SPECIES
Authors: Flinn Cindy L. , Ashworth Edward N.
Published: April 2024

Little is known about the biochemical factors responsible for the wide range in flower bud hardiness of Forsythia species. In other genera, a correlation has been reported between soluble sugars, particularly raffinose and stachyose, and hardiness. Total starch and soluble sugars, their relationship to flower bud hardiness and levels of individual sugars were studied in four Forsythia species: F. × intermedia `Spectabilis', F. × intermedia `Lynwood', F. suspensa var. fortunei and F. `Meadowlark'. Hardiness was determined either by sampling flower buds at intervals during controlled freezing tests or by thermal analysis. Total sugars were extracted with water/ethanol and quantified with Anthrone. Individual sugars were separated and quantified with high pressure liquid chromatography. `Lynwood', the least hardy of the four cultivars, was killed by -16C, while `Spectabilis, the most hardy, survived -22C in midwinter. Total sugars accumulated throughout the winter in buds, apparently at the expense of total starch, in F. `Meadowlark' and F. suspensa var fortunei. As total sugars accumulated in `Spectabilis', however, total starch increased slightly. Although fructose, glucose, galactose and melibiose were detected throughout the year, raffinose and stachyose, were detected only in hardy flower buds.
EFFECT OF PRETREATMENT ON THE THERMOTOLERANCE OF DORMANT Vitis vinifera cv. CABERNET SAUVIGNON HARDWOOD CUTTINGS
Authors: Wample Robert L. , Mills Lynn
Published: April 2024

The relationship between heat tolerance and cold hardiness was examined during the winter of 1992-93. Dormant canes of Cabernet Sauvignon were collected from an experimental vineyard at approximately two to three week intervals. Samples were held overnight at 0-3 C. Subsamples were removed from storage and subjected to either room temperature for 4 1/2 hours, 45 C for 35 minutes followed by room temperature for 4 hours or held at 0-3 C. Samples were then subjected to either heat treatment (52, 54, 56, 58, or 60 C for 30 minutes) or low temperature exotherm analysis.

Pretreatment at 45 C improved the heat tolerance but did not change cold tolerance. Holding samples at room temperature resulted in a slight improvement in heat tolerance. Additional implications of these findings will be presented.
FRUIT CHARACTERISTICS OF SOME CITRUS SPECIES IN RELATION TO HEAT AND DROUGHT STRESSES
Authors: Shaheen Mohamed A. , El-Agamy Samir Z.
Published: April 2024

Fruit characteristics of 8 citrus species and cultivars including orange (Valencia, Hamlin, Temple and Navel), tangarine (Dancy), lemon (Lisbon) and grapefruit (Marsh and Ruby) were studied on trees grown under strong heat and drought stresses. Environmental stresses resulted in extreme influences on fruit shape, rind thickness and color and juice percentage. Dancy tangarine and Navel orange were completely depleted from juice. Fruitstended to be round, thicker rind and less juice content in other species. TSS and ascorbic acid contents were slightly lower than their standards while acidity was markedly decreased.
REDUCING BELL PEPPER FLOWER ABSCISSION WITH ETHYLENE INHIBITORS IN FIELD EXPERIMENTS.
Authors: Wien H.C. , Turner A.D.
Published: April 2024

In previous research, pepper flower abscission has been brought about by ethylene, and prevented under greenhouse conditions by the ethylene action inhibitor silver thiosulfate (STS). Field experiments in 1991 and 1992 compared the abscission response and yield of `Shamrock', `Ssupersweet 860' and `Lady Bell' when treated with foliar sprays of STS (l×l0-3 M or 5×l0-3 M), or the ethylene synthesis inhibitor AVG (50 or l00ppm), applied at flowering. Abscission, measured a week after the chemicals were applied, was reduced from 16 to 4% in 1991, and from 16 to 5% in 1992 by the higher STS rate but not affected by AVG. `Ssupersweet' and `Shamrock' averaged 14% abscission during the measurement interval, while `Lady Bell' had 8%. Treatments did not change marketable yields, but the high rate of STS increased total and cull fruit numbers by 35 and 41%, respectively. All cultivars showed similar abscission and yield responses to the treatments.
REDUCTION IN ETHYLENE PRODUCTION INDUCED BY POSTHARVEST HEAT TREATMENT OCCURS WITHOUT AN APPARENT DECREASE IN ETHYLENE-FORMING ENZYME ACTIVITY
Authors: Forcherio Joseph L. , Sams Carl E. , Conway William s.
Published: April 2024

Apples (Malus domestica Borkh cv. `Delicious') were stored after harvest for 2 weeks at 0 C. Fifteen fruit (5 fruit per replication, 3 replications) were then removed from storage and heated (38 C, 3 days) and 15 fruit remained in storage (control). After treatment the fruit were returned to storage for 2 months at 0 C. The fruit were then removed from storage and assayed for 1-aminocyclopropane-l-carboxylic acid (ACC) activity and ethylene production. The ability of the fruit tissue to convert ACC to ethylene was also determined by utilizing ACC spiked samples. Heat significantly lowered the ethylene production rate. However, the conversion of ACC to ethylene was not different between treatments when samples were spiked with 1 μM of ACC. This indicates that ethylene forming enzyme (EFE) activity was not affected by the heat treatment. The effect of heat treatment on ACC concentration and the conjugation of ACC into 1-malonylaminocyclopropane-l-carboxylic acid (MACC) will be discussed.
CHARACTERIZATION OF Ca2+-TRANSLOCATING ATPase FROM PLASMA MEMBRANE VESICLES OF SOUR CHERRIES
Authors: Campbell W.F. , Anderson J.L.
Published: April 2024

Calcium maintains plasma membrane integrity, osmoregulation and extends the quality of shelf-life of sour cherry, Prunus cerasus L., fruit. Cherry fruit clusters were sprayed with Calcium Metalosate [an amino acid calcium chelate (AACa), Albion Labs, Inc., Clearfield, UT] solution. AACa-treated and untreated cherries were hand-harvested and placed in plastic bags. For comparison of Ca compounds, hand-harvested cherries were placed in cold tap water or 2% calcium chloride (CaCl2). All cherry samples were transported on ice to the lab, stored at 4°C for 24-48 h, and processed for membrane-enriched vesicle fractions. Membrane protein content was about 4-fold greater in Ca-treated fruit than in controls. 45Ca2+ uptake by the vesicles was ATP-dependent with the radiotracer accumulated by the vesicles being released when the calcium ionophore A23187 was added. ATPase activity and H+-pumping were both completely inhibited by orthovanadate, suggesting that the fractions were free from non-plasma membrane ATPases. Because CaCl2 is caustic and causes corrosion of equipment, our results suggest that spraying AACa may offer an alternative application of Ca.