bluuebunny/crossref_metadata_2025 huggingface dataset:
Survey of Gooseberry Mite Infestation in Ribes L.
Authors: Hummer Kim E. , Postman Joseph D. , Carter John , Gordon Stuart C.
Published: February 2019

During Dec. 1997 and Jan. 1998, the gooseberry mite, Cecidophyopsis grossulariae Collinge, was observed to infest 48 currant and gooseberry (Ribes L.) cultivars in a field plantation in Corvallis, Ore. The mite was observed on 29 black currant, (Ribes nigrum L.), two red currant [Ribes rubrum L. and R. sativum (Rchbch.) Syme], 12 gooseberry [R. uvacrispa L., R. oxyacanthoides var. setosum (Lindley) Sinnot], and three R. ×nidigrolaria Bauer cultivars and the hybrid R. nigrum × R. pauciflorum Turcz. ex Pojark. A range of mite infestation levels was observed, with some cultivars not being infested, some with light infestation, having 1 to 100 adult mites per bud, and some heavily infested, with more than 100 mites per bud. On lightly infested buds, the mites were inside bud and leaf scales; in heavily infested buds, mites were also observed on floral primordia. Scales of infested buds were often loose and appeared more open than noninfested ones. Mite distribution varied by branch within a plant. Black currant cultivars with the heaviest infestation of C. grossulariae were of Scandinavian, Russian, Scottish, and Canadian origin. The Russian black currant cultivar Tunnaja was the most heavily infested with more than 1000 mites per bud. Floral primordia were damaged in heavily infested buds.
Strategy for Combining Heat Treatment, Calcium Infiltration, and Biological Control to Reduce Postharvest Decay of `Gala' Apples
Authors: Conway William S. , Janisiewicz Wojciech J. , Klein Joshua D. , Sams Carl E.
Published: February 2019

The viability of Penicillium expansum Link conidia in sporulating culture declined rapidly when exposed to 38 °C, and when conidia were exposed to 38 °C prior to inoculation of apple fruits (Malus ×domestica Borkh.), the resulting lesions were smaller than those on fruit inoculated with nonheated conidia. `Gala' apples were heated after harvest (38 °C for 4 days), pressure infiltrated with a 2% solution of CaCl2, or treated with the antagonist Pseudomonas syringae van Hall, alone or in combinations to reduce postharvest decay caused by Penicillium expansum. After up to 6 months in storage at 1 °C, no decay lesions developed on fruit that were heated after inoculation with P. expansum, or any combination of P. expansum, antagonist, or Ca. Parallel lots of heat-treated and nonheated fruit that were either infiltrated or not infiltrated with Ca were stored up to 6 months. They were then inoculated with P. expansum alone, or with the antagonist followed by P. expansum. Prior heat treatment did not influence lesion size. Calcium alone, the antagonist alone, and heat plus Ca all reduced the incidence of decay by ≈25%, whereas heat plus the antagonist reduced it by 70%. Calcium plus the antagonist or Ca plus the antagonist and heat reduced decay incidence by 89% and 91%, respectively. The integrated strategy of heat-treating fruit, followed by Ca infiltration and then treatment with an antagonist, may be a useful alternative to controlling postharvest decay with fungicides.
Redevelopment of Tissue Proliferation Symptoms in Rooted Rhododendron Cuttings
Authors: Brand Mark H. , Kiyomoto Richard
Published: February 2019

Tissue proliferation (TP) of Rhododendron sp. is characterized by basal tumors that often develop into numerous dwarf shoots. Growers need to know if the TP condition will recur in plants grown from normal-appearing cuttings collected from plants with TP tumors. Stem cuttings of seven cultivars were collected from stock plants with TP [TP(+)] and without TP [TP(–)] and rooted. Plants were grown in containers outdoors for 2 years and were then evaluated for tumor formation and other TP-related morphological symptoms. Shoots of TP(+) plants were either similar in length to shoots of TP(–) plants, or were shorter, as was the case for `Boule de Neige', `Catawbiense Album', and `Montego'. Plants grown from TP(+) cuttings of all cultivars had more leaves per growth flush than did plants grown from TP(–) cuttings. `Holden', `Montego', and `Scintillation' TP(+) leaves were narrower than leaves from TP(–) shoots and had greater length: width ratios. Leaves of TP(+) `Montego' and `Scintillation' plants were shorter and smaller than leaves from their TP(–) counterparts. Tumors were not observed on any propagated plants, regardless of the TP status of cutting stock plants. To further test the influence of age and TP status of source plants used for cutting propagation, `Montego' plants were grown from cuttings collected from the following sources: 1) in vitro shoot cultures; 2) 3-year-old plants with TP; 3) 6-year-old plants with TP; and 4) TP(–) plants. Cuttings from TP(+) micropropagated plants less than 3 years old were more likely to develop tumors than were cuttings from older plants. Eighty-three percent of plants from microcuttings and 74% of plants from cuttings of 3-year-old TP(+) plants formed tumors, whereas no plants grown from 6-year-old TP(+) or TP(–) cuttings did so. Large tumors that surrounded half or more of the stem were more likely to develop on plants grown from microcuttings than on plants grown from the next youngest, 3-year-old TP(+), stock plants. Growers must be aware that cuttings from TP(+) plants may produce plants that exhibit morphological and growth abnormalities, possibly even including tumor redevelopment.
Consumer Preferences for Geranium Flower Color, Leaf Variegation, and Price
Authors: Behe Bridget , Nelson Robert , Barton Susan , Hall Charles , Safley Charles D. , Turner Steven
Published: February 2019

Researchers often investigate consumer preferences by examining variables consecutively, rather than simultaneously. Conjoint analysis facilitates simultaneous investigation of multiple variables. Cluster analysis facilitates development of actionable market segments. Our objective was to identify relative importance and consumer preferences for flower color, leaf variegation, and price of geraniums (Pelargonium ×hortorum L.H. Bail.) and to identify several actionable market segments. We also evaluated the desirability of a hypothetical blue geranium. Photographic images were digitized and manipulated to produce plants similar in flower area, but varying in flower color (red, lavender, pink, white, and blue), leaf variegation (plain green, dark green zone, and white zone), and price ($1.39 to $2.79). Conjoint analysis revealed that flower color was the primary consideration in the purchase decision, followed by leaf variegation and price. A cluster analysis that excluded blue geraniums yielded four actionable consumer segments. When preferences for the blue geranium were included, six consumer segments were identified.
Mechanical Conditioning of Tomato Seedlings Improves Transplant Quality without Deleterious Effects on Field Performance
Authors: Garner Lauren C. , Björkman Thomas
Published: February 2019

Excessive stem elongation reduces plant survival in the field and hinders mechanical transplanting. Mechanical conditioning is an effective method for reducing stem elongation during transplant production. This investigation examined the consequences of mechanical conditioning, using brushing and impedance, on subsequent field performance of tomatoes (Lycopersicon esculentum Mill.). Mechanically conditioned transplants of processing tomatoes resumed growth after transplant shock as quickly as did untreated plants, and subsequent canopy development was also equal. In 4 years of field trials, yield was not reduced by mechanical conditioning. Transplants for fresh-market tomatoes may be more sensitive to injury than those for processing tomatoes because they flower sooner after the conditioning treatments. Nevertheless, neither earliness nor defects in the fruits of the first cluster were affected by mechanical conditioning. Early and total yields were equal in both years that fresh-market crops were tested. Thus, there were no adverse effects on field performance of either processing or fresh-market tomatoes as a result of reducing stem elongation by mechanical conditioning before transplanting. Improved wind tolerance was tested both in a wind tunnel and in the field. In wind-tunnel tests, brushed and impeded plants resisted stem bending at wind speeds 4 to 12 km·h–1 higher than did untreated plants. A 70 km·h–1 wind after transplanting killed 12% of untreated plants but only 2% of treated plants. Mechanical conditioning with brushing and impedance produced transplants with desirable qualities without adverse effects on field performance.
Use of Cold Water for Irrigation Reduces Stem Elongation of Plug-grown Tomato and Cabbage Seedlings
Authors: Chen Junne-Jih , Sun Yung-Wei , Sheen Tzay-Fa
Published: February 2019

Seedlings of tomato (Lycopersicon esculentum Mill.) and cabbage (Brassica oleracea L. var. Capitata) were planted in 240-cell plug trays in the greenhouse and subjected to irrigation with water at different temperatures once a day. Irrigation with cold (5 to 15 °C) water reduced stem length of tomato by 28% to 32% in comparison with irrigation with water at room temperature (27.5 to 30.5 °C). Use of water at 10 °C did not affect total shoot dry weight but increased the shoot dry weight per centimeter of stem. Irrigation with water at 5 °C reduced stem length of cabbage seedlings 40%, but use of water at 10 and 15 °C did not. Both shoot and root dry weights were increased by irrigation with water at 10 °C. These results demonstrate that irrigation with cold water provides an effective method for improving the quality of plug-grown seedlings.
Low-temperature Tolerance of Blackcurrant Flowers
Authors: Carter John , Brennan Rex , Wisniewski Michael
Published: February 2019

The low-temperature tolerance of flowers from three blackcurrant (Ribes nigrum L.) cultivars, `Brödtorp', `Ben Tirran', and `Baldwin', was determined at two stages of floral development. The three cultivars together represent a large part of the available genetic base for this subgenus of Ribes. Plants were maintained either at 4 °C in a growth cabinet under a 16-hour photoperiod or outdoors in Scotland during Spring 1997. Observed genotypic differences in survival were not associated with differences in LT50 of the flowers, and observations of freezing damage to flowers on intact plants suggest that the flowers can often survive by supercooling. This hypothesis is partly confirmed by the finding that detached flowers from all three cultivars have the capacity to supercool to at least –9 °C. Ice nucleation in stem tissue, however, was found to occur at or above –2 °C. That flowers on intact plants can apparently survive by supercooling, together with the finding that ice nucleation in stem tissue occurs at temperatures well above the LT50 of flowers, indicate the presence of barriers to propagation of ice from stem tissue to raceme. Such barriers within individual racemes are also indicated by patterns of freezing damage to flowers on intact plants cooled to –5 °C.
Screening Eucalyptus Clones for Salt Tolerance
Authors: Grieve C.M. , Guzy M.R. , Poss J.A. , Shannon M.C.
Published: February 2019

Agroforestry plantations offer environmentally acceptable strategies for the reuse of saline drainage waters. Tree species suitable for use in such systems must be selected for survival and sustained growth under highly saline conditions. In this screening trial, four clones of Eucalyptus camaldulensis Dehn. (4543, 4544, 4573, and 4590) and one clone of E. rudis Endl. (4501) were grown in greenhouse sand cultures irrigated with sodium sulfate–dominated waters. Solution compositions were prepared to simulate saline drainage waters typically found in the San Joaquin Valley of California. Electrical conductivities of the solutions ranged from 2 to 28 dS·m–1. Treatments were replicated three times. All plants survived and were harvested after 7 weeks under saline treatment. Plant height was measured weekly and shoot biomass was determined at final harvest. The salinity levels that resulted in a 50% reduction in biomass production (C50) were 16.4 (4573), 17.1 (4543), 17.7 (4544), 29.0 (4590), and 30.0 dS·m–1 (4501). Over the range of salinities from 4 to 20 dS·m–1, clones 4501, 4590, and 4573 generally maintained higher relative growth rates (RGR) than did clones 4544 and 4543. However, at the highest salinity, RGRs of clones 4501, 4544, and 4573 were significantly greater than those of clones 4543 and 4590. Assessed on the basis of biomass production, clones 4501 (E. rudis) and 4590 (E. camaldulensis) showed exceptional potential for use in agroforestry systems where the saline drainage waters are sodium sulfate–dominated.
The Response of Several Citrus Genotypes to High-salinity Irrigation Water
Authors: Levy Y. , Lifshitz J. , De Malach Y. , David Y.
Published: February 2019

The effect of irrigation with saline water on several citrus genotypes was evaluated in a short-term field experiment. Salinity levels ranged from 2.0 to 6.4 dS·m–1. Comparatively salt-tolerant Citrus species and Citrus × Poncirus hybrids were tested for their possible use as rootstocks for commercial citrus cultivars irrigated with brackish water. All the tested genotypes survived the highest salinities. At all salinity levels, the best chloride excluder was Cleopatra mandarin (Citrus reshni Hort. ex Tan.), and the worst was sour orange (C. aurantium L.). Gou Tou Cheng (C. aurantium hybrid?) and Rangpur (C. limonia Osb.) × Troyer citrange (C. sinensis L. × Poncirus trifoliata L.) RT803 were found to be promising genotypes for further evaluation as rootstocks tolerant to high salinities. Rangpur was unsuitable because of foot rot.
Injurious Effects of Metsulfuronmethyl When Used to Stimulate Abscission of `Hamlin' Oranges
Authors: Kender W.J. , Hartmond U. , Salyani M. , Burns J.K. , Whitney J.D.
Published: February 2019

A field experiment was conducted to determine effects of concentration and spray volume of metsulfuron-methyl as an abscission aid for mechanical harvesting of citrus. Concentrations of 1, 2, and 4 mg·L–1 metsulfuron-methyl were applied to `Hamlin' orange [Citrus sinensis (L.) Osbeck] trees at 470, 1900, and 4700 L·ha–1 (0.5 to 19 g·ha–1 a.i.). Effective fruit loosening was achieved with all applications >1.9 g·ha–1 (4 mg·L–1 at all volumes, 2 mg·L–1 at 1900 and 4700 L·ha–1, and 1 mg·L–1 at 4700 L·ha–1). Heavy defoliation and twig dieback were observed on trees receiving 2 and 4 mg·L–1 at all volumes. Defoliation and dieback became more severe and flower development and fruit set were inhibited as fruit loosening increased. The use of metsulfuron-methyl as an abscission agent for `Hamlin' oranges is not recommended until conditions for its safe application can be determined. Chemical names used: methyl 2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl) amino] carbonyl] amino] sulfonyl] benzoate (metsulfuron-methyl).
Effect of Ultraviolet-reflective Mulches on Tomato Yields and on the Silverleaf Whitefly
Authors: Csizinszky A.A. , Schuster D.J. , Polston J.E.
Published: February 2019

Field studies were conducted for three seasons, Fall 1994, Spring 1995, and Fall 1995, on the effect of ultraviolet (UV)-reflective films (mulches) on the silverleaf whitefly (Bemisia argentifolii Bellows and Perring), the incidence of tomato mottle virus (ToMoV), and on fruit yields of staked, fresh-market tomatoes (Lycopersicon esculentum Mill.). The UV-reflective mulches were metallized aluminum (aluminum) and painted aluminum (silver) on either black or white plastic film. The aluminum and silver mulches were evaluated with and without a white (fall) or black (spring) 25-cm-wide painted band in the bed center. Controls were the conventional white (fall) or black (spring) polyethylene mulches. Highest reflected energy (μmol·m–2·s–1) to the plants at 15 cm from the mulch surface was measured on the aluminum mulch with or without a white painted band. Lowest energy was reflected from the white or black controls and from silver on black mulches with or without a black painted band. Whitefly populations in the fall were lower (P ≤ 0.05) on the aluminum than on the silver mulches. In the spring, when whitefly populations were low, whiteflies were more numerous on the black control and silver on white, than on the aluminum mulches. In the fall seasons, the proportion of plants with symptoms of ToMoV transmitted by the silverleaf whitefly were higher on the controls than on the aluminum mulch. In the spring, the proportion of plants with symptoms was not affected by mulch treatments. Yields in the fall were similar with UV-reflective or white control mulches. In the spring, fruit size and marketable yields were greater (P ≤ 0.05) on plants with silver on white mulch than on the control black mulch.
Magnetic Resonance Imaging of Browning Development in `Braeburn' Apple during Controlled-atmosphere Storage under High CO2
Authors: Clark Christopher J. , Burmeister Douglas M.
Published: February 2019

Development of browning induced in `Braeburn' apple (Malus ×domestica Borkh.) fruit by a damaging CO2 concentration was monitored weekly using magnetic resonance imaging (MRI) during a 4-week storage trial (0.5 °C, 2 kPa O2/7 kPa CO2). Discrete patches of high-intensity signal, distributed randomly throughout the fruit, were observed in multislice images of samples after 2 weeks of storage; these patches were eventually confirmed as being sites of browning reactions after dissection at the end of the trial. Subsequently (weeks 3 and 4), signal intensity at sites of incipient damage increased and patches enlarged and coalesced. After 2 weeks of storage, the extent of affected tissue, averaged across all image slices, was 1.5%, increasing to 15.9% and 21.3% after 3 and 4 weeks. The average rate at which tissue damage spread in individual slices was 0.81 (range: 0–3.70) cm2·d–1 between weeks 2 and 3, declining to 0.32 (range: 0–1.55) cm2·d–1 in the final week. Tissue damage induced under these conditions did not spread at the same rate at all locations within individual fruit, nor was it preferentially located toward the stem or calyx ends of the fruit.
Growth and Yield of F1 Hybrid Peaches Developed from Doubled Haploids
Authors: Scorza Ralph , Pooler Margaret
Published: February 2019

Doubled haploid peach [Prunus persica (L.) Batsch] lines were cross-pollinated to produce F1 hybrids. F1 hybrids were evaluated at 3, 7, 8, and 9 years after field planting for tree growth as measured by trunk cross-sectional area, and for fruit production as measured by total weight, total number, and production per unit trunk cross-sectional area. Fruit quality of most F1 hybrids was within the range of quality observed in progeny of standard peach cultivars, and tree growth and productivity were similar to those of standard cultivars. F1 hybrids present the possibility of developing scion varieties that can be produced from seed, thus eliminating the need for grafting scions onto rootstocks in situations where specific, adapted rootstocks are not necessary. They could also be used to develop genetically uniform seed-propagated rootstocks. The use of doubled haploid-derived F1 peach hybrids, however, would require reliable, efficient production techniques.
Chilling Temperature and Duration Interact on the Budbreak of `Perlette' Grapevine Cuttings
Authors: Dokoozlian N.K.
Published: February 2019

A factorial experiment examined the interaction between chilling temperature (0, 2.5, 5.0, 7.5 and 10 °C) and duration (50, 100, 200, 400, and 800 h) on the budbreak of `Perlette' (Vitis vinifera L.) grapevine cuttings. Cuttings stored at 0 °C exhibited the most rapid budbreak during the first 30 days after being placed under forcing conditions. After this period, chilling temperature had relatively little influence on cumulative budbreak, with cuttings stored between 0 and 10 °C generally exhibiting similar rates of budbreak. In contrast, the slope of the budbreak curves increased, indicating more rapid and uniform budbreak, with increased chilling duration. Significant interactions (P ≤ 0.0001) between chilling temperature and duration were found for both the number of days required for 50% budbreak and total observed budbreak. The number of days required for 50% budbreak declined, while total observed budbreak increased, with increased chilling duration. Within the temperature range evaluated, a minimum exposure of 200 hours was required to achieve commercially acceptable levels of budbreak.
Influence of Cranberry Soil Surface Characteristics on the Activity of Dichlobenil
Authors: Sandler Hilary A. , DeMoranville Carolyn J.
Published: February 2019

Field conditions associated with commercial cranberry (Vaccinium macrocarpon Ait.) production were simulated in greenhouse studies to determine the effect of soil surface characteristics on dichlobenil activity. Sand was compared with organic matter, in the form of leaf litter, as the surface layer. A seedling bioassay using alfalfa (Medicago sativa L.), a dichlobenil-sensitive plant, was employed to determine root growth response on herbicide-treated soil. When the herbicide was applied to a sand surface, root growth was greater as time after application elapsed, indicating loss of herbicide activity. Conversely, the presence of organic matter on the surface prolonged the activity of the herbicide. Composition of the surface layer was more important than the depth of the layer in determining herbicide persistence. The influence of cultural practices, such as the application of sand or the removal of surface debris, on herbicide activity should be considered when planning weed management strategies for cranberry production. Chemical name used: 2,6-dichlorobenzonitrile (dichlobenil).
Occurrence and Development of a Dorsal Gland in Leaves of Ficus benjamina L. (Weeping Fig) Cultivars
Authors: Pennisi Svoboda V. , McConnell Dennis B. , Henley Richard W.
Published: February 2019

Detailed anatomical observations of the dorsal gland and its development in Ficus benjamina L. (Weeping Fig) leaves are reported. The dark spot on the abaxial surface of Ficus benjamina leaves is a normal morphological feature of the species. It is a highly specialized modified epidermal layer. An investigation of six commercially available cultivars revealed all possessed a glandular dorsal epidermis but not all developed a pigmented gland. The variability in gland thickness suggests that differences exist between cultivars. Based on histochemical tests, we propose that the term “phenolic gland” be substituted for the term “wax gland” found in the literature, as all tests indicated the presence of polyphenols in the glandular epithelium of F. benjamina leaves.
Growth, Opium Gum Yield, and Photoperiod Response of Five Opium Poppy Accessions
Authors: Wang Z. , Acock M.C. , Liu Q. , Acock B.
Published: February 2019

Flowering time, growth, and opium gum yield from five seed sources (T, L, B1, B2, B3) of opium poppy (Papaver somniferum L.) collected from different latitudes in three Southeast Asian countries were determined. Plants were grown in six growth chambers at a 11-, 12-, 13-, 14-, 15-, or 16-hour photoperiod with a 12-hour, 25/20 °C thermoperiod. Flower initiation was observed under a dissecting microscope (40×) to determine if time to floral initiation was identical for all accessions across a wide range of photoperiods. The main capsule was lanced for opium gum at 10, 13, and 16 days after flowering (DAF). Plants were harvested at 21 DAF for plant height, leaf area, and organ dry-weight determinations. In a 16-hour photoperiod, flower initiation was observed 10 days after emergence (DAE) for B1 vs. 8 DAE for the other four accessions. Flowering time was affected most by photoperiod in B1 and least in B2. Flowering times for B3, L, and T were similar across the range of photoperiods. B2, B3, and L had the highest gum yields per capsule; even though B1 had the greatest total plant biomass, it produced the lowest gum yield. There was no difference among accessions in the average ratio of gum: individual capsule volume. For the ratio of gum: capsule dry weight, only the difference between T and B1 was significant. Capsule size did affect these ratios slightly. T had a larger gum: volume ratio for larger capsules, and B3 had a smaller gum: dry-weight ratio for heavier capsules. Flowering time varied up to 40%, capsule dry weight up to 41%, and opium gum yield up to 71% for the five accessions across all treatments. No relationship was found between flowering time and the latitude where the seed sources were collected. Time to flower initiation could not be used to predict time to anthesis because floral development rates varied significantly among accessions and photoperiods. Capsule volume and dry weight were useful in estimating gum yield.
Root Pruning Reduces Photosynthesis, Transpiration, Growth, and Fruiting of Container-grown French-American Hybrid Grapevines
Authors: Ferree D.C. , Scurlock D.M. , Schmid J.C.
Published: February 2019

`Seyval blanc' and `Vidal blanc' grapevines (Vitis sp.) grown in large containers were root-pruned at different severities and/or stages of development and the effects on growth of both cultivars and fruiting of `Seyval blanc' were determined. As the severity of root pruning increased, stomatal conductance (gs) and transpiration (E) decreased and the number of wilted leaves increased in both cultivars. In both cultivars, root pruning reduced net photosynthesis (Pn) and E for as long as 18 to 20 days, as well as total leaf area and dry weight of leaves and petioles plus tendrils. The reductions were proportional to the degree of root pruning. A similar pattern existed for cane and root tissue of `Vidal blanc'. As the severity of root pruning increased, berry and cluster weight, and titratable acidity (TA) of `Seyval blanc' decreased. There was no effect of root pruning on berries per cluster, soluble solids content (SSC), or pH of the juice. No interaction was significant for any factor between time of root pruning and fruiting measured on `Seyval blanc' vines. Root pruning at bloom reduced leaf area, number of leaves, and dry weight of petioles, trunks, and canes. Root pruning at veraison had no effect on any vegetative or fruit parameters. Fruiting `Seyval blanc' vines had less leaf area and smaller petiole and cane dry weights than did nonfruiting vines.
Plant Population Affects Yield and Fruit Size of Pumpkin
Authors: Reiners Stephen , Riggs Dale I.M.
Published: February 2019

Field studies were conducted in 1996 on two pumpkin (Cucurbita pepo L.) cultivars, `Howden' (vining-type growth habit) and `Wizard' (semi-bush growth habit), at two locations to determine the effect of plant population and row width on marketable yield. Increasing plant populations from 2990 to 8960 plants per hectare resulted in significantly greater fruit number and yield at both locations and for both varieties. Average fruit size declined at the highest populations. Increasing row width from 1.8 to 3.6 m resulted in a slight but significant decrease in number of fruit per hectare with no effect on other yield parameters. At one location, the effect of row width on yield and number of fruit per hectare depended on the population. At low populations, row width did not influence yield or fruit number; at high populations, wide rows produced lower yield and fewer fruit than narrow rows. The results demonstrate that growers may increase pumpkin yield by increasing plant populations but should use narrower row widths and wider in-row spacing. Growers who choose higher populations should ensure that all inputs are optimized to reduce potential plant-to-plant competition and use regionally adapted cultivars.
Cutleaf Evening Primrose and Palmer Amaranth Reduce Growth of Nonbearing Pecan Trees
Authors: Wolf Margaret E. , Smith Michael W.
Published: February 2019

Growth of `Apache' pecan [Carya illinoinensis (Wangenh.) K. Koch] seedlings was evaluated for 3 years when grown in a 11.2-m2 weed-free area or when various combinations of one or two plants of cutleaf evening primrose (Oenothera laciniata Hill), a cool-season species, or Palmer amaranth (Amaranthus palmeri S. Wats.), a warm-season species, were grown 30 cm from the tree, with the rest of the 11.2-m2 area weed-free. Either weed species alone suppressed tree growth compared to the weed-free control. A temporal succession of primrose followed by amaranth reduced growth most. After 3 years, two plants of primrose followed in succession by two of amaranth caused a 79% reduction in cumulative current-season's growth.
Embryo Elongation and Germination Rates as Sensitive Indicators of Lettuce Seed Quality: Priming and Aging Studies
Authors: Hacisalihoglu G. , Paine D.H. , Hilderbrand M.B. , Khan A.A. , Taylor A.G.
Published: February 2019

High-quality seed lots are required for successful establishment of horticultural crops. Testing methods are needed that can detect the early phases of aging prior to a significant loss in germination. Quality was assessed using both germination speed and uniformity on non-primed and primed, as well as non-aged and aged, lettuce (Lactuca sativa L.) seed. Speed and uniformity were quantified using time to 50% (T50) germination and one standard deviation (Tsd), respectively. Embryo elongation was developed as a rapid test by first soaking seeds for 2 hours, then cutting and removing the distal one-third of the seed, and finally observing the percentage of visibly elongated embryos from the seed coverings over time. The mild aging conditions employed in this study (45 °C and 50% relative humidity for up to 21 days) had little influence on viability (germination in all treatments was >98%), but reduced germination rate (increased the time for T50 and Tsd). Primed seeds aged faster than non-primed seeds under the same aging conditions. The percentage of elongated embryos was calculated at hourly intervals after cutting, and treatment differences were observed after a total hydration period of 5 hours. The embryo elongation test detected aging in both primed and non-primed treatments.
Resistance of Peach and Plum Rootstocks from Spain, France, and Italy to Root-knot Nematode Meloidogyne javanica
Authors: Pinochet Jorge , Calvet Cinta , Hernández-Dorrego Adriana , Bonet Ariadna , Felipe Antonio , Moreno Marian
Published: February 2019

Two trials involving 20 Prunus rootstocks were conducted under greenhouse conditions to screen for resistance to root-knot nematode [Meloidogyne javanica (Treub.) Chitwood]. Many of the tested materials are interspecific hybrid rootstocks and represent new commercial peach (P. persica Batsch) and plum (Prunus sp.) releases or experimental genotypes of Spanish, French, and Italian origin. In the first trial, the rootstocks Adesoto 101 (P. insititia L.), Bruce (P. salicina Lindl. × P. angustifolia Marsh.), Ishtara, AC-952 (P. insititia), Garnem [P. dulcis (Mill.) D.A. Webb × P. persica], Cadaman [P. persica × P. davidiana (Carr.) Franch], and Orotava (P. salicina) were immune or resistant to a mixture of 10 isolates of M. javanica. The remaining rootstocks, Myrocal (P. cerasifera Ehr.), Montclar (P. persica), and Adafuel (P. dulcis × P. persica), were susceptible. In the second screening trial, the plum rootstocks Adesoto 101, Adara (P. cerasifera), Myro-10 (P. cerasifera), Constantí (P. domestica L.), and AD 105 (P. insititia) were immune to the root-knot nematode. Cadaman, G × N No. 17 (P. dulcis × P. persica), and Tetra (P. domestica) were resistant. Laroda F1OP (P. salicina), Myro-almond (P. cerasifera × P. dulcis), and the peach–almond hybrids Mayor, Adafuel, and Sirio were susceptible.
Identification of the Edible Fig `Bianco del Cilento' by Random Amplified Polymorphic DNA Analysis
Authors: Galderisi U. , Cipollaro M. , Di Bernardo G. , De Masi L. , Galano G. , Cascino A.
Published: February 2019

Random amplified polymorphic DNA (RAPD) analysis is currently used to estimate genetic relationships in plants. We have used RAPD analysis to distinguish six different cultivars of Ficus carica, and several of their clones, that are widespread in the Campania Region of Southern Italy. Among these cultivars, `Bianco del Cilento' has unique characteristics, and is particularly useful for drying and for the manufacture of syrups. The protection of this cultivar is important to the Campania Region. We have utilized molecular markers to allow accurate identification of this cultivar, making it possible to control the quality of products and prevent fraudulent commerce. DNA was extracted from leaves and amplified by PCR using random oligonucleotide primers. The amplification patterns obtained with five decamer primers were useful for distinguishing all six cultivars analyzed. `Bianco del Cilento' was identified by two primers. The banding patterns were scored and used in similarity value calculations to estimate genetic relationships.
Improved Plant Regeneration from Suspension-cultured Cells of Iris germanica L. `Skating Party'
Authors: Wang Yuexin , Jeknić Zoran , Ernst Richard C. , Chen Tony H.H.
Published: February 2019

To improve the efficiency of iris plant regeneration, we tested the influence of several combinations of Kin and NAA in culture media on the induction of morphogenesis and the subsequent development of plantlets. The highest rates of regeneration (67%) were consistently observed in induction media containing 0.5 μm NAA and either 2.5 or 12.5 μm Kin. Developing medium containing 1.25 μm BA was optimal for high regeneration rates and a high percentage of plantlets simultaneously developing shoots and roots. Rooted plantlets were easily acclimatized and transplanted to various soil mixtures, then grown in the greenhouse. Under optimal conditions as many as 8000 plantlets could be regenerated from 1 g of cells in ≈4 months. Chemical names used: kinetin (Kin); 1-naphthaleneacetic acid (NAA); N6-benzyladenine (BA).
Medium-term Storage of Apricot Shoot Tips In Vitro by Minimal Growth Method
Authors: Pérez-Tornero O. , Ortín-Párraga F. , Egea J. , Burgos L.
Published: February 2019

Apricot (Prunus armeniaca L. cv.'Helena') shoots grown on a proliferation medium containing 3% sucrose, 0.4 mg·L–1 benzyladenine (BA), and 0.04 mg·L–1 indolebutyric acid (IBA) and solidified with 0.6% agar were stored at three different temperatures in the dark for up to 24 weeks. All shoots remained viable for 24 weeks when stored at 3 °C, while at 14 °C the percentage of survival decreased quickly after 12 weeks of storage. At 7 °C, percentage of survival started to decline after 18 weeks of storage. Shoots stored at 3 °C had the highest regeneration rates and shoot lengths following transfer to standard proliferation conditions. This temperature also had a beneficial effect on shoot proliferation during the first 12 to 18 weeks of the experiment.
Apple Bruise Detection by Electrical Impedance Measurement
Authors: Jackson Phillipa J. , Harker F. Roger
Published: February 2019

Electrical impedance was used to determine the extent of tissue damage that occurred as a result of bruising of apple fruit (Malus ×domestica Borkh, cvs. Granny Smith and Splendour). Impedance measurements were made before and after bruising. Plots of reactance against resistance at 36 spot frequencies between 50 Hz and 1 MHz traced a semicircular arc, which contracted in magnitude after bruising. A number of characteristics of these curves were then related to bruise weight. The change in resistance that occurred as a result of fruit impact (ΔR50Hz) was the best predictor of bruise weight, with r2 values up to 0.71. Before bruising, resistance of fruit was higher in `Splendour' than in `Granny Smith' (P < 0.001), and at 0 °C than at 20 °C (P < 0.001), but was not influenced by fruit weight. The influence of apple cultivar and temperature on electrical impedance may cause difficulties when implementing these measurements in a commercial situation. However, further development of electrical impedance spectroscopy methodologies may result in convenient research techniques for assessing bruise weight without having to wait for browning of the flesh.
The Use of Mentor Pollination to Facilitate Wide Hybridization in Blueberry
Authors: Wenslaff Timothy F. , Lyrene Paul M.
Published: February 2019

Two diploid yellowleaf Vaccinium elliottii Chapmn. clones were pollinated with pollen from the tetraploid southern highbush cultivar `Misty' (largely V. corymbosum L). These interspecific crosses, which normally yield few hybrids because of a triploid block, were made with and without the use of V. elliottii mentor pollen mixed with V. corymbosum pollen. Mentoring had no effect on the number of hybrids produced when V. elliottii `Silverhill' was the seed parent, but when V. elliottii `Oleno' was the seed parent, no hybrids were produced unless mentor pollen was utilized. The difference was postulated to be a greater ability to produce one-seeded berries in `Silverhill' than in `Oleno'.
Performance of New Banana Germplasm in South Florida
Authors: Ploetz Randy C. , Haynes Jody L. , Vázquez Aimé , Benscher David
Published: February 2019

In 1995, 37 new dessert and cooking bananas (Musa spp.) were introduced into South Florida for evaluation under local edaphic and environmental conditions. The number of pseudostems per mat, height at fruiting, and cycling time were determined during the first fruiting cycle, and bunch number and bunch weight were recorded from 1996 to 1998. A productivity index (PIX), calculated as 100 × mean bunch weight in kg/cycling time in days, was used to determine the productivity of the clones over time. Informal taste panels assessed the appearance and organoleptic qualities of fruit on a subjective 1 to 4 scale. In a separate experiment, the susceptibility of 30 of the clones to fusarium wilt, caused by Fusarium oxysporum f. sp. cubense, was assessed. Some of the most popular and productive clones were susceptible to fusarium wilt and are not recommended for production in areas that have a history of this disease. The dessert clones `Pisang Ceylan', FHIA01', FHIA02', and FHIA17' and the cooking accessions `Kandrian', `Kumunamba', and `Saba' resisted fusarium wilt, produced moderate to high yields (PIXs ≥ 1) of good to excellent fruit (mean ratings ≥ 3), and are recommended for use in all areas in Florida.
Response of Cybrids and a Somatic Hybrid of Lemon to Phoma tracheiphila Infections
Authors: Tusa Nicasio , Del Bosco Sergio Fatta , Nigro Franco , Ippolito Antonio
Published: February 2019

The reaction of lemon hybrids obtained by symmetrical and asymmetrical protoplast fusion, toward “mal secco” infection caused by Phoma tracheiphila (Petri) Kanc. et Ghik. was examined. Resistance was tested in `Valencia' sweet orange [Citrus sinensis (L.) Osbeck] and `Femminello' lemon [C. limon (L.) Burm. f.] somatic hybrid and cybrids, by stem and leaf inoculation tests and by analysis of propagule number of P. tracheiphila in the xylem of stem-inoculated plants. In general, the somatic hybrid and the cybrids showed an intermediate degree of resistance, with slight differences in disease symptoms, in comparison with resistant `Monachello' lemon and susceptible `Femminello' lemon, used as controls. The lower mortality in the asymmetrical lemon cybrids suggests that specific mechanisms of resistance to the disease could be activated in these genotypes.
Response of Rhododendron `Montego' with “Tissue Proliferation” to Cytokinin and Auxin In Vitro
Authors: Brand Mark H. , Ruan Yiqin , Kiyomoto Richard
Published: February 2019

To characterize the in vitro behavior of Rhododendron `Montego' with tissue proliferation (TP) to cytokinin and auxin, comparisons were made of normal [TP(–)], dwarf TP [TP(+) dwarf], and long TP [TP(+) long] shoot cultures. On basal medium TP(–) and TP(+), long shoots failed to multiply and had a low relative growth rate (RGR) of 0.1, whereas TP(+) dwarf shoots produced 31.8 shoots per tip, with most shoots being <5 mm long, and RGR was 0.3. Addition of 15 μm 2iP to basal medium induced the production of more than six shoots per TP(–) tip and doubled their RGR; TP(+) long shoots produced 16.8 shoots, most <5 mm long, and had an RGR of 0.3; TP(+) dwarf shoots produced only 16% as many shoots as on basal medium, but still exhibited an increase in RGR. Leaves from TP(–) and TP(+) sources failed to produce shoots on basal medium, but 74% of TP(–) leaves formed shoots when cultured on 1 μm IBA and 30 μm 2iP. TP(+) leaves were able to form shoot meristems on media containing only 5 μm 2iP (26% of explants), but these meristems failed to elongate into shoots. Calli from TP(–) leaves, TP(+) leaves, and TP(+) tumors grown on medium containing 10 μm NAA and 15 μm 2iP had higher RGRs than the same calli on basal medium during the first 8 weeks of culture. Over time, RGR decreased in both TP(–) and TP(+) leaf calli, but increased in TP(+) tumor callus. The increased RGR resulted from differentiation of shoot meristems on 85% of the calli between week 4 and week 8. Our results suggest that TP(+) tissues have altered hormone metabolism or sensitivity that leads to dramatic differences in in vitro behavior and probably contributes to tissue proliferation observed in whole plants. Chemical names used: 6-(γ,γ-dimethylallylamino) purine (2iP); indole-3-butyric acid (IBA); α-naphthaleneacetic acid (NAA).
Resistant Responses of Peach Somaclone 122-1 to Xanthomonas campestris pv. pruni and to Pseudomonas syringae pv. syringae
Authors: Hammerschlag F.A.
Published: February 2019

A detached-leaf bioassay was used to evaluate peach [Prunus persica (L.) Batsch] somaclone 122-1 (derived from callus produced on an immature embryo of peach cultivar Redhaven) for resistance to several virulent strains of Xanthomonas campestris pv. pruni [E.F. Sm.) Dows], causal agent of bacterial leaf spot, and to a virulent isolate of Pseudomonas syringae van Hall pv. syringae, causal agent of bacterial canker. The detached-leaf bioassay was also used to evaluate progeny of 122-1 for resistance to X. campestris pv. pruni virulent strain XP1. Somaclone 122-1 was significantly more resistant to most strains of X. campestris pv. pruni than was `Redhaven', and all of its progeny exhibited high levels of resistance to X. campestris pv. pruni strain XP1. Somaclone 122-1 exhibited significantly higher levels of resistance to Pseudomonas syringae pv. syringae than did `Redhaven' and this resistance was retained over time in the greenhouse and following a 2-year cycle of tissue culture propagation.
Container Substrate Temperatures Affect Mineralization of Composts
Authors: Kraus Helen T. , Mikkelsen Robert L. , Warren Stuart L.
Published: February 2019

Traditional N mineralization studies have been conducted by soil scientists using soils and temperatures found in field production. As temperature, in part, governs the rate of mineralization, and container substrates reach much higher temperatures than do soils, the effect of these elevated temperatures on mineralization must be considered to begin to understand N mineralization in container substrates during production. The N mineralization patterns of three composts [turkey (Meleagris gallopavo) litter, yard waste, and municipal waste] were determined under three temperature regimes (45, 25, and 45/25 °C). More organic N was mineralized from composted turkey litter (CTL) than from municipal or yard composts, regardless of temperature. The percentage of organic N mineralized from CTL was greater at 45/25 and 45 °C than at 25 °C.
Growth Retardants Affect Growth and Flowering of Scaevola
Authors: Starman Terri W. , Williams Millie S.
Published: February 2019

The effects of concentration and method of application of uniconazole on growth and flowering of Scaevola aemula R. Br. `New Wonder', `Mini Pink Fan', `Purple Fan', and `Royal Fan', Scaevola albida (Sm.) Druce. `White Fan', and Scaevola striata `Colonial Fan' were studied, as was the efficacy of four other growth retardants on S. aemula `New Wonder'. Variables measured included plant width, flower stem number, flower stem length, flower number per stem, flower number per cm stem length, and days to flower. Uniconazole (1.0 mg·L–1) applied as a medium drench to S. aemula `New Wonder' reduced plant width and flower stem length without affecting flower stem number or time to flower. Flower number per stem and number of flowers per cm of stem length were increased, resulting in attractive, compact clusters of flowers. Paclobutrazol medium drench at 4.0 mg·L–1 gave similar results. Daminozide and ethephon sprays reduced plant width; however, flower number was reduced and ethephon delayed flowering. Ancymidol did not affect the parameters measured. When uniconazole drenches were applied to the other cultivars, plant width and flower stem length in all cultivars except `White Fan' decreased as rate increased. Spray applications reduced plant width of all cultivars except `Mini Pink Fan'. Flower stem length was not affected in any cultivar. Flowering habit was improved more in S. aemula `New Wonder', `Purple Fan', and `Royal Fan' than in the other cultivars. Chemical names used: α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol); butanedioic acid mono (2,2-dimethylhydrazide) (daminozide); (2-chloroethyl)phosphonic acid (ethephon); β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol); (E)-(s)-1-(4-chlorophenyl)-4,4-dimethy-2-(1,2,4-triazol-1-yl)-pent-1-ene-3-ol (uniconazole).
Temperature, but not Growth Regulators, Influences Diurnal Stem Elongation Rhythms in Zinnia
Authors: Neily Will G. , Hicklenton Peter R. , Kristie David N.
Published: February 2019

Experiments were conducted to determine the effects of treatment with gibberellic acid (GA) on changes in diurnal growth rhythms caused by maturation and day/night temperature differential (DIF) in zinnia (Zinnia elegans Jacq. `Pompon'). Plants were treated with GA3 or with the GA biosynthesis inhibitor daminozide under three DIF regimes (+5 DIF: 21 °C DT/16 °C NT; 0 DIF: 18.7 °C constant; –5 DIF: 16.5 °C DT/21.5 °C NT), each with a daily average temperature of 18.7 °C, at two developmental stages: stage 1, the period of vegetative growth before flower bud formation; and stage 3, growth just before anthesis. Instantaneous stem elongation rates (SER) were measured using linear voltage displacement transducers. The DIF regime, as has been previously shown, influenced stem elongation primarily by altering the size of an early morning peak in SER; peak height increased as DIF became more positive. GA3 increased SER throughout the diurnal period with a proportionately larger effect on nighttime growth. Conversely, daminozide decreased SER more or less equally throughout the diurnal period. Neither GA3 or daminozide transformed growth patterns to match those of positive or negative DIF plants, but instead simply increased or decreased growth amplitude. Furthermore, neither growth regulator altered the basic diurnal SER pattern at any DIF, or influenced the observed shift to greater nighttime growth as plants matured from stage 1 to stage 3. The results suggest that neither the effects of DIF, or the age-related shift in diurnal growth distribution can be explained by changes in total availability of GA in the plant. Chemical name used: mono (2,2-dimethylhydrazide) butanedioic acid (daminozide).
Tomato Responses to Preplant-incorporated or Fertigated Phosphorus on Soils Varying in Mehlich-1 Extractable Phosphorus
Authors: Carrijo Osmar Alves , Hochmuth George
Published: February 2019

Experiments were conducted to evaluate the yield response of tomato (Lycopersicon esculentum Mill.) to P, either preplant-incorporated or injected through the drip irrigation system, on soils with low, high, or very high soil P content. Fertilization through the drip irrigation system (fertigation) was more efficient than preplant incorporation of P for soil that tested low in P (9 mg·kg–1 Mehlich-1 P). On soil testing low in P, marketable yield response to preplant soil P application rates (0 to 100 kg·ha–1) was maximum at 61 kg·ha–1 P according to the linear-plateau model, but 37 kg·ha–1 P according to the quadratic-plateau model. The lower value is about one-half the P recommended by Univ. of Florida for low-P soils. On soil testing high in P (48 mg·kg–1 Mehlich-1 P) the linear-plateau model predicted a maximum yield of 72.8 t·ha–1 with 25 kg·ha–1 P. The Univ. of Florida recommended no P for that soil. On soil testing very high in P (85 mg·kg–1 Mehlich-1 P), there was no yield improvement with P fertilization.