bluuebunny/crossref_metadata_2025 huggingface dataset:
DAY AND NIGHT CONCENTRATIONS OF N AND C METABOLITES IN TOMATO SEEDLINGS GROWN IN SOLUTION WITH VARIOUS NITRATE CONCENTRATIONS
Authors: Ma Yona-Zhan , Gent Martin P.N.
Published: February 2019

Nitrate (NO3) was supplied at 100, 200, 400, and 800 μm in nutrient solution to 3-week-old tomato seedlings grown hydroponicly, and day and night concentrations of N and C metabolites were measured. Tissue [NO,] at the end of the night was greater than at the end of the day, especially for leaves. Leaf tissue [NO3] was about 350 μmol·g-1 dry weight at night, 3 times as high as that during the day. Generally, root and stem tissue [NO,] was similar and higher than that of leaves and increased as medium [NO,] increased. The difference was greater at night than during the day. During the day, total free amino acid concentration was the greatest for roots and the least for stem. Generally, root tissue had higher total free sugar concentration than leaf and stem tissues during the day. Fructose concentration was lower at night than during the day for all parts of the plants, especially for roots. At night, NO3 accumulated in plant tissues, especially in leaves, and was not incorporated into amino acids, perhaps due to the lack of energy and reductant.
EFFECT OF NAA OR ACCEL SPRAYS ON YIELD AND FRUIT SIZE OF `EMPIRE' APPLE ON THREE ROOTSTOCKS
Authors: Schupp J.R. , Bates. M.M. , Brummer H.J.
Published: February 2019

`Empire' is a popular new apple with fruit growers in the northeastern United States, noted for producing small-sized fruit. To test the efficacy of chemical thinners and rootstocks for increasing fruit size of `Empire', three-tree plots containing trees on M.7 EMLA, MM. 111, and seedling rootstocks were chemically thinned at petal fall with 10 ppm NAA or 85 ppm 6 BA, applied as Accel. Both NAA and Accel reduced fruit set. Trees on M.7 EMLA had higher set than trees on seedling. Yield was highest on M.7 EMLA and lowest on seedling. Fruit diameter after final set in July was increased by both chemical thinners and was greater for both clonal rootstocks than for seedling. Fruit on seedling trees were delayed in maturity relative to the two clonal rootstocks. Accel increased the number of fruit 70 mm or greater in diameter, while NAA increased the number of fruit in the 64- to 69-mm-diameter class. Analysis of covariance with crop load suggested that the increase in fruit size associated with Accel was a direct effect rather than a secondary effect from thinning.
LIPIDS IN SUBEPIDERMAL CORTICAL TISSUE OF `GOLDEN DELICIOUS' APPLE FRUIT
Authors: Whitaker Bruce D.
Published: February 2019

Altered metabolism of membrane lipids has been proposed as a mechanism for the beneficial effects of postharvest calcium treatment on apple quality. A previous study showed that after transfer of apples stored 6 months at 0C to 20C, calcium-treated fruit exhibited slower loss of galactolipid and altered levels of sterol conjugates. The present study of lipids in “control” fruit was conducted as a prelude to further in-depth analyses of the effects of postharvest calcium and heat treatments on lipid metabolism in apples during and after cold storage. Neutral lipid, glycolipid (GL), and phospholipid (PL) fractions were obtained by column chromatography followed by TLC separation of GL and PL classes. The major GL were steryl glycosides (SG), acylated steryl glycosides (ASG), cerebrosides (CB), and mono- and digalactosyl diacylglycerols. Phosphatidylcholine (PC) > P-ethanolamine (PE) > P-irositol (PI) were the major PL. The fatty acids of PC and PE were quite similar, whereas those of PI were more saturated. CB included only 2-hydroxy fatty acids. Among the steryl lipids, free sterols > SG > ASG, with beta-sitosterol >90% of the total sterol in each.
EVALUATION OF ORGANIC RESIDUES FOR THE PRODUCTION OF FLOWERING POT PLANTS
Authors: Gauthier Fabienne , Dansereau Blanche , Gagnon Serge
Published: February 2019

During Winter 1994, seedlings of Impatiens wallerana `Accent Coral' and Pelargonium ×hortorum `Orbit Hot Pink' were grown in commercial substrate (Pro-Mix BX) or in one of the 24 substrates composed of six organic residues (composted water-treated sludge, forestry compost, fresh or composted used peat extracted by a biofilter during treatment of municipal water, and fresh or composted paper sludge). These residues were incorporated with peatmoss and perlite at 5%, 10%, 25%, and 40% per volume to obtain the 24 substrate combinations. Plants were watered and fertilized by flooding of ebb-and-flow benches. Growth measurements (growth index, top and root dry weight, number of flowers and buds, visual quality) varied considerably depending on the percentage of residue incorporated into the substrates. Moreover, substrates containing 40% of organic residues are not recommended for production of impatiens or geraniums.
BA Influences Flowering and Dry-matter Partitioning in Shoots of `Crimson Giant' Easter Cactus
Authors: Boyle Thomas H.
Published: February 2019

The effects of BA concentration on flowering and dry-matter partitioning in shoots of `Crimson Giant' Easter cactus [Rhipsalidopsis gaertneri (Regel) Moran] were investigated. Treatments were applied 12 days after starting the forcing phase (before flower buds were visible) and included BA at 0, 10, 50, 100, and 200 mg·liter–1. Relative to the controls, BA increased the total number of flower buds per plant and delayed flowering by 2 to 3 days. The percentage of aborted flower buds increased more than 3-fold as BA concentration increased from 0 to 50 mg·liter–1 and increased further when 100 or 200 mg·liter–1 was applied. The number of flower buds that reached anthesis increased quadratically with increasing BA concentration and was maximal when plants were treated with 50 mg·liter–1. As BA concentration increased from 0 to 200 mg·liter–1, total dry weight of phylloclades decreased, whereas dry weight of floral tissue increased by a nearly equivalent amount. BA increases flowering and alters partitioning of dry matter in reproductive plants of `Crimson Giant'. Chemical name used: N-(phenylmethyl)-1H-purine-6-amine (BA).
Cooling Method Influences the Postharvest Quality of Broccoli
Authors: Gillies S.L. , Toivonen P.M.A.
Published: February 2019

The effects of cooling method and packaging with perforated film on broccoli (Brassica oleracea L. Italica group) quality during 2C storage were studied. Broccoli was either room-cooled, top-iced, or hydrocooled before being placing into storage for 14 days. Hydrocooling was the most rapid cooling method and resulted in the lowest vapor pressure deficits between the broccoli and the surrounding air. Hydrocooling and top-icing resulted in similar firmness and color retention. Broccoli that was hydrocooled and then overwrapped with perforated film lost less weight, was firmest, and retained color better than either top-iced or room-cooled broccoli.
Characterization of Some Self-compatible Almonds. II. Flower Phenology and Morphology
Authors: Bernad D. , _ _
Published: February 2019

Bloom evolution and flower quality were studied in 10 almond [Prunus amygdalus Batsch syn. P. dulcis (Mill.) D.A. Webb] selections of the Zaragoza breeding program. The opening of individual flowers followed a normal distribution, with deviations reflecting temperature differences during the bloom period. The first open flowers are of better quality than later ones and may contribute more to fruit set. The relative stigma–anther position reflected the possibility of natural autogamy in three of the 10 selections. Natural autogamy might allow single-cultivar orchards without the need for pollinating insects.
EFFECTS OF NITROGEN RATES AND FINAL FALL HARVEST TIMING ON SAGE (SALVIA OFFICINALIS)
Authors: Maness N.E. , Motes J.E. , Bostian B. , Schatzer R.J.
Published: February 2019

Sage is a perennial, semi-evergreen herb and is a multiharvest crop. In a 4-year field study in Bixby, Okla., three N rates, including 60, 120, and 180 kg/h, and four fall harvest dates, including 40 and 20 days before the average first freeze date in Bixby, the average freeze date, and 20 days past the average freeze date were evaluated on sage (Salvia officinalis) production. The fall harvest dates were ≈20 Sept., 10 Oct., 1 Nov., or 20 Nov. each year. Plots were established with transplants in Spring 1990. On all plots, growing-season harvests were executed once in spring and once in summer, followed by the final harvest in the fall annually (1991 to 1994). Results indicated N effects on yield and the N × final fall harvest date interaction were not significant for any of the years. Yields were significantly reduced in the 40 and 20 days prefreeze date harvest treatment plots in 1992, 1993, and 1994 by a hard freeze of –7C on 2 Nov. 1991 with no prior killing frost. Plant stand loss was 61% and 8% in the 40 and 20 days prefreeze harvested plots, respectively. Injury, but not plant loss, in the 20 days prefreeze harvested plots contributed to the yield reduction. Yields in the two later final harvest treatment plots were not affected.
PRECISION SEEDING FOR PLANTING CAULIFLOWER TO A STAND
Authors: Bracy R.P. , Parish R.L. , Moser E.B.
Published: February 2019

Field studies were conducted in Fall 1991 and 1992 to determine if cauliflower (Brassica oleracea L. Botrytis Group) could be precision seeded to a stand without subsequent thinning and what the optimum seed spacing necessary to directly seed cauliflower to a stand. Seed spacings of 10, 20, and 30 cm at one seed per hill and 30 cm at two seeds per hill were evaluated for effect on yield, head weight, plant population, and early harvest percentage. As evaluated in the laboratory, seeder precision (accuracy) was good with regard to seed counts and spacing measurements at the various seed spacings. Seeder precision evaluated in the field varied in distribution patterns among seed spacings and years. Cauliflower was successfully precision seeded to a stand without thinning during 2 years of fall plantings. Cauliflower directly seeded at one seed per hill and a 20-cm spacing produced total and average head weights similar to cauliflower seeded 10 cm apart and thinned to 30 cm—the seeding method currently used by some commercial operators.
FIELD DIAGNOSTIC TOOLS FOR ESTIMATING NITROGEN NEEDS FOR FRESH-MARKET TOMATOES IN KENTUCKY
Authors: Jones R. Terry , Ditsch David C.
Published: February 2019

In Kentucky, fresh-market tomato production is a 3-million-dollar crop involving 405 to 486 ha. During the 1980s, on-farm demonstrations showed yields and grower returns increased when intensive production practices were followed. Fertigation recommendations were based on a 1 N: 2 K ratio with a total of 225 kg N/ha. Symptoms of Mg deficiency and blossom-end rot sometimes were seen, and we were concerned about potentially high fertilizer concentrations in the plant root zone. Farm fertility trials (1992 to 1994) showed no yield response to applied N rates between 101 and 393 kg·ha–1. In 1993, a presidedress N test (PSNT) (NO3 + NH4-N) indicated 131 kg N/ha was available in the top 31 cm of soil. At the final tomato harvest, 343, 529, and 647 kg NO3 + NH4-N was measured in the top 46 cm of soil for the three N rates tested (191, 298, and 391 kg N/ha). In 1994, the PSNT showed 86 kg NO3 + NH4-N/ha was present in the top 31 cm of soil. At final harvest 58, 124, and 157 kg NO3 + NH4-N/ha was measured in the top 91 cm of soil for the 140, 225, and 309 kg N/ha applied. Tomato phenology vs. petiole NO3-N concentration showed that all three N levels gave similar values, with no clear distinction between petiole NO3-N and the N rates tested. Future tests need to include a zero applied N rate to determine if a predictable relationship exists between a PSNT or petiole NO3-N levels and a yield response to fertilizer N.
BLACKBERRY TRELLISES
Authors: Stiles Herbert D.
Published: February 2019

The Stiles bent fence (SBF) and single-sided shift trellis (SSST) are differently designed structures that function to isolate fruiting zones of summer-fruiting brambles on one side of the plant or row. The SBF and SSST are suited for use with cultivars that produce long, flexible, nonbranched canes. Summer pruning of stiff-caned, semi-erect types may encourage development of long, flexible lateral branches that are adaptable for training on these trellises; alternate-year cropping may be helpful where such pruning is necessary. The SSST operates on the same principles as our original single-sided trellis (SST), but the newer design is compatible with a broader range of commonly available construction materials. Construction plans will be published in a Virginia Agricultural Experiment Station Bulletin as soon as funds are made available. The SSST should allow greater manual harvest efficiency, more effective IPM, fewer yield losses to sunscald, compatibility with cultural management practices, lower costs of postharvest precooling, better condition of harvested fruit for maximum shelf life, and stronger prospects for machine harvesting of fresh-market brambles.
MINIATURE POTTED ROSE PRODUCTION USING COMPOSTED POULTRY LITTER AS A MEDIA COMPONENT
Authors: McDonald Garry V. , Pemberton H. Brent , Baker Marvin L. , Mondier Jo
Published: February 2019

Liners of Rosa `MEIrutral' (=Red Sunblaze) were potted in 11.5-cm pots using Fison's Sunshine Mix no. 2 amended with 0%, 10%, 20%, or 30% composted poultry litter (PL) by volume. Plants were grown for 3 weeks before cutting back to 5 cm for final forcing (short-cycle) and were fertilized with 200 mg N/liter from 20N–8.9P–16.6K on a three feed and one leach schedule for the duration of the experiment. By flowering, plants growing in the 30% PL media were dead or stunted. However, there was little difference in total number of flowers, days to flower, and root and shoot dry weight between the other treatments. Media pH rose from 6.6 to 7.4 and EC rose from 0.7 to 6 millimhos with increasing PL content. This result alone could explain the poor growth in the highest PL rate treatment. However, tissue N levels were supraoptimal for the 20% and 30% PL rates, and tissue P levels were excessive for all PL rates. If a high-quality source of composted PL is available, it could be used as a media component for potted rose production at rates <20%, but monitoring of pH and EC and modifying fertilization techniques may be necessary to ensure success.
INTERMITTENT WARMING DELAYS CHILLING INJURY IN OKRA
Authors: Perkins-Veazie P. , Collins J.K.
Published: February 2019

Okra develops chilling injury after 4 to 5 days at 2C or 8 days at 5C. Intermittent warming has prevented or delayed chilling injury in warm season crops. The purpose of this experiment was to find a way to prevent or delay chilling injury in okra. Field grown `Annie Oakley', `Blondy', and `Clemson Spineless' okra pods were held constantly at 2, 5, or 10C or placed at 2C or 5C for 2 days followed by 2 days at 10C (2-10 and 5-10, respectively) then returned to their original temperature. After 8 days of storage, all boxes were placed at 20C for 1 day; color was measured with a colorimeter, and pods were rated subjectively for chilling injury. `Annie Oakley' and `Clemson Spineless' pods held at 2C were olive-green to brown; okra held at 2-10 was green and still marketable. Less chilling injury occurred to pods held at 5 and 5-10 compared to those at 2C. Pods held at 2-10, 5, or 5-10 had injury after 8 to 10 days of storage compared to 5 days at 2C. Although chilling injury could not be completely prevented in okra by intermittent warming, shelf life could be lengthened by cooling pods at 2C for no more than 2 days to eliminate field heat and reduce weight loss, followed by storage at a higher temperature.
PECAN COLD HARDINESS DETERMINED BY DIFFERENTIAL THERMAL ANALYSIS
Authors: Matta Frank B. , Kawatin Amin
Published: February 2019

Stem critical temperatures for September showed that `Hughes' was later in acclimating than `Jackson'. Maximum hardiness for all cultivars occurred in January and deacclimation in February. Bud critical temperatures for September and October also showed that `Hughes' acclimated later than the other cultivars. Maximum hardiness for buds occurred in January and deacclimation in March. In December, the LT50 for the tetrazolium test, the electrolyte leakage test, and the tissue browning test were –18, –20, and –20C, respectively, as shown by differential thermal analysis of `Desirable'.
APPLICATION OF UV-C AND BIO-CONTROL AGENT STRATEGIES TO CONTROL ROT OF FRUIT AND VEGETABLES
Authors: Stevens C. , Khan V.A. , Lu J.Y. , Wilson C.L. , Pusey P.L. , Kabwel M.K. , Mafolo Y. , Liul J. , Chalutz E. , Droby S.
Published: February 2019

Applying low doses of ultraviolet light (254 nm, W-C) reduces the incidence of brown rot of (Monilinia fructicola) peaches, green mold (Penicillium digitatum) of tangerines, and Rhizopus soft rot (Rhizopus stolonifer) of tomatoes and sweetpotatoes resulting from field infection and artificial inoculation. In most studies, applying postharvest fungicide (PF) was better than W-C treatment. In this study, the effectiveness of combining a biocontrol agent, Debaryomyces hansenii (BC), with low UV-C dose for postharvest disease control was investigated. When these commodities were treated with BC 3 days after W-C treatment, the reduction of storage rots was more effective than when UV-C was used alone. For example, the percent brown rot infection of artificially inoculated Elberta peaches 36 hours after inoculation of the nontreated control, peaches treated with UV-C, BC, W-C + BC, and benlate were 100%, 55%, 67%, 12%, and 12%, respectively. The efficacy of W-C + BC was similar to when PF was used alone, indicating that an integration of UV-C treatment and BC can reduce storage rot to the levels of commercial PF treatment.
ASSESSMENT OF ATTITUDE AND KNOWLEDGE CHANGES OF SECONDARY HIGH SCHOOL STUDENTS PARTICIPATING IN A MULTIDISCIPLINARY, ACTIVITY-BASED, ENVIRONMENTAL SCIENCE CURRICULUM
Authors: Campbell Amy N. , Zajicek J.M. , Townsend C.D.
Published: February 2019

A study was developed to compare secondary high school students' knowledge and attitude changes toward environmental issues after the completion of an interdisciplinary instructional unit in environmental science. The population for the study was high school horticulture and environmental science students. The study consisted of four student groups, including two control groups and two experimental groups, one each from an environmental science class and a horticulture class. The control groups did not participate in the treatment, which consisted of an environmental mini-unit and plant propagation experiment that the experimental groups completed. Both student groups responded to a pre- and posttest questionnaire. There were no significant differences in overall attitude scores between treatment and control groups. Significant differences were noted in knowledge gains between the horticulture control group and treatment group, with students participating in the mini-unit scoring significantly higher in knowledge gain. There was also a positive correlation between attitude scores of students who had success with their propagation experiments. The results of this study indicate that it is important to test students' attitudes and knowledge when determining the effectiveness of new environmental curriculum. The high correlation between success in the propagation experiment included in the miniunit and attitude supports findings that an activity-based curriculum has the potential to raise the awareness of students on environmental issues.
MEDIA AMENDED WITH BROILER LITTER COMPOST DID NOT AFFECT POINSETTIA GROWTH
Authors: Allen V.V. , Behe B.K. , Krentz T.S. , Montgomery C.C.
Published: February 2019

Organic wastes have the potential to contaminate ground and surface water supplies when overused in agronomic crop production. Poultry manure contains organic N and can be composted and partially substitute for fertilizer or peatmoss in plant production. Our objective was to determine the effects on growth of poinsettias `Freedom' and `Supjibi Red' grown in media amended with broiler litter compost (BLC). Media were developed to resemble a commercial peat-lite medium by blending BLC, peatmoss, and perlite, by volume (BLC: peat: perlite) at 1:3:4, 2:2:4, 3:1:4, and 4:0:4. Plant height, growth indices, number of fully developed bracts, and visual marketability rating were not affected by adding BLC to the media.
RESPONSE OF SWEETPOTATOES TO WINTER COVER CROPS
Authors: Porter Wayne C.
Published: February 2019

Rye, wheat, hairy vetch, ryegrass, and Austrian winterpea were evaluated for effects on weed control and sweetpotato production. Sweetpotatoes were transplanted into these cover crops after the cover crops had been killed with glyphosate and mowed. One-half of each plot was treated with clomazone herbicide and one-half was not treated. Plots with rye residues contained fewer goosegrass, rice flatsedge, ground cherry, and smooth pigweed plants than other cover crop plots. Sweetpotato plant vigor was greatest in the rye plots. Goosegrass, crabgrass, groundcherry, and eclipta were controlled in cover crop plots treated with clomazone. Sweetpotato plant vigor was better in the plots treated with clomazone than in plots with a cover crop only. Highest yields of no. 1 grade and total marketable sweetpotatoes were in rye and ryegrass cover crop plots, with or without clomazone. Sweetpotatoes grown in Austrian winterpea plots without clomazone produced the lowest yields. There was an increase in yield of sweetpotatoes in all cover crop plots treated with clomazone.
Enhanced Root and Shoot Growth of Chrysanthemum Cuttings Propagated with the Fungus Trichoderma harzianum
Authors: MacKenzie Amy J. , Starman Terri Woods , Windham Mark T.
Published: February 2019

Trichoderma harzianum Rifai, a fungus that controls soilborne pathogens, can enhance growth of several vegetable and floriculture crops. Zero, 5, or 25 g of T. harzianum (isolate T-12) peat–bran amendment was added per kilogram medium in an effort to enhance the rooting of four chrysanthemum [Dendranthema ×grandiflorum (Ramat.) Kitamura] cultivars, two considered easy to root (`Davis' and `White Marble') and two considered hard to root (`Dark Bronze Charm' and `Golden Bounty'). Adding the T. harzianum amendment at both rates tested increased root and shoot fresh weights during 21 days of rooting, relative to the control. Supplementary treated cuttings were transplanted into nontreated growing medium after 21 days. Midway between transplant to flowering, increases in height, shoot dry weight, and root fresh and dry weight were detected in `Dark Bronze Charm' with T-12, relative to the control; increases in height, shoot fresh and dry weight, and number of nodes were detected in `Golden Bounty' with T-12. By this time, there were no detectable differences in `Davis' or `White Marble'.
Using SPAD-502 Values to Assess the Nitrogen Status of Apple Trees
Authors: Neilsen Denise , Hogue Eugene J. , Neilsen Gerald H. , Parchomchuk Peter
Published: February 2019

Four apple (Malus domestica Borkh) cultivars (`Fuji', `Spartan', `Fiesta', and `Gala') on Malling 9 (M.9) rootstock were grown in the field with three N rates (5, 20, and 35 g N/tree per year), supplied as Ca(NO3)2, and fertigated daily for 9 weeks. In the second year, leaf SPAD readings (chlorophyll readings obtained with the Minolta-502 SPAD meter) increased over the growing season for all cultivars, and leaf N decreased. Leaf SPAD and leaf N measurements increased in response to N fertigation rate at all sampling times. `Gala' consistently had lower SPAD readings than the other cultivars, and, with the exception of the first sampling time, `Fuji' had higher and `Fiesta' lower leaf N concentrations than other cultivars. There were strong relationships between leaf N concentration and SPAD readings for all cultivars until mid-July (r2 = 0.44 to 0.89), but not later in the growing season. Differences in SPAD readings and leaf N concentration due to cultivar and over time were as great as those due to N treatments, indicating that in the future, determination of critical SPAD values for apple leaves must be standardized for cultivar and sampling time. SPAD readings could be used to assess the need for N early in the growing season in fertigated orchards where rapid changes in nutrition programs can be undertaken readily.
Growth and Survival of `Whitespire' Japanese Birch Grafted on Rootstocks of Five Species of Birch
Authors: Ranney Thomas G. , Whitman Everett P.
Published: February 2019

A 3-year study was conducted to evaluate growth and survival of trees grafted onto five species of birch rootstocks. `Whitespire' Japanese birch (Betula platyphylla var. japonica Hara.) was grafted onto paper birch (B. papyrifera Marsh), European birch (B. pendula Roth), river birch (B. nigra L.), Szechuan birch [B. szechuanica (C. Schneid.) Janson], and `Whitespire' Japanese birch rootstocks and grown under field conditions. Trees grafted onto river, European, paper, and `Whitespire' birch rootstocks had similar (100% to 60%) survival rates. Trees on Szechuan rootstock had a survival rate of 30%, which was lower than that of all other rootstocks, except `Whitespire'. `Whitespire' scions grafted onto European birch rootstocks had thicker trunks, were higher, and had wider canopies than trees grafted onto `Whitespire' rootstocks. Trees on river birch rootstocks also had thicker trunks but similar tree heights and canopy widths as trees grafted onto `Whitespire'. `Whitespire' Japanese birch rootstocks produced more rootstock suckers than any of the other rootstocks, while trees on river birch rootstocks had the most frost cracks. No signs of graft incompatibility were observed for any of the graft combinations. These results demonstrate that growth of `Whitespire' birch can be enhanced by grafting this cultivar on rootstocks of other species, including European and river birch.
Cold Storage and Hot-water Immersion as Quarantine Treatments for Canistel Infested with Caribbean Fruit Fly
Authors: Hallman Guy J.
Published: February 2019

Canistel [Pouteria campechiana (HBK.) Baehni] fruit were subjected to cold storage and hot-water immersion treatments known to kill immature Caribbean fruit flies [Anastrepha suspensa (Loew)] in other fruit. Cold storage at 1 or 3C for 17 days did not cause appreciable loss in canistel quality compared with fruit stored at the normal 10C. Unripe canistels immersed in water at 46C for 90 min or at 48C for 65 min, however, developed dark blotches on the peel and a 2- to 3-mm-thick layer under the peel that did not soften. Canistels were infested with Caribbean fruit flies and subjected to 1 or 3C storage for up to 14 days. The resulting lethality data were fitted to three probability density functions (PDF) to estimate the number of days required to achieve quarantine security (99.9968% dead). The normal and Gompertz PDFs gave some reasonable estimates, while the logistic PDF gave low estimates. At 1C, 14 days would be needed to achieve quarantine security, while at 3C a minimum of 15 days would be required. These estimates must be tested to determine if they are valid after a large amount of Caribbean fruit fly immatures is subjected to the treatments.
A Radiation-induced Mutant with Resistance to Common Bacterial Blight Disease in Common Beans
Authors: Mohamed Mohamed F. , Coyne Dermot P. , Read Paul E.
Published: February 2019

The leaf reaction of the Phaseolus vulgaris L. germplasm—UNECA (M6 mutant derived from the cultivar Chimbolito, Costa Rica), `Chimbolito', BAC-6 (Brazil), XAN-159 (Centro Internacional de Agricultura Tropical, Cali, Colombia), and `PC-50' (Domican Republic)—to Xanthomonas campestris pv. phaseoli strain V4S1 (Dominican Republic) were determined in two replicated trials conducted in a greenhouse in Lincoln, Neb. (Feb.–Mar. and July–Aug. 1993). `PC-50' and `Chimbolito' were susceptible to Xcp strain V4S1 in both tests. UNECA, BAC-6, and XAN-159 had similar levels of resistance to Xcp in the July to August trial. However, in the February to March trial, the resistance of UNECA was greater than that of BAC-6 but less than that of XAN-159.
Calcium Sprays and Timing Affect Fruit Calcium Concentrations, Yield, Fruit Weight, and Cork Spot of `Anjou' Pears
Authors: Raese J.T. , Drake S.R.
Published: February 2019

Calcium sprays (CaCl2, Mora-Leaf-Ca + Link Ca, or Stopit) increased fruit Ca concentrations and reduced the incidence of cork spot of `Anjou' pears (Pyrus communis L.) during four seasons. All Ca sprays increased yield relative to the control. All sprays resulted in some injury to leaves and fruit, but fruit was acceptable for marketing. At the low rate, Stopit sprays were the least injurious. Early season sprays, in June to July, produced less leaf and fruit injury than late-season sprays, in July to August, or early + late-season sprays. Early or late-season Ca sprays resulted in slightly larger fruit than early + late sprays. Either late or early + late-season sprays led to higher Ca concentrations in fruit cortex than early sprays.
Shoot Regeneration in Vitro from Diverse Genotypes of Sweetpotato and Multiple Shoot Production per Explant
Authors: Gosukonda Ramana M. , Prakash C.S. , Dessai Ananta Porobo
Published: February 2019

Studies were conducted to improve adventitious shoot regeneration in sweetpotato [Ipomoea batatas (L.) Lam.], specifically to extend the protocol to many genotypes and to elicit production of multiple shoots per explant. The use of a two-stage procedure where excised petioles were incubated on Murashige and Skoog (MS) (1962) medium with 2,4-D (0.2 mg·liter–1) for 3 days and transferred to a second medium containing MS salts with thidiazuron and 2iP (0.05 mg·liter–1 each) resulted in shoot regeneration from eight of 13 genotypes tested, including elite sweetpotato cultivars such as `Jewel' and `Rojoblanco'. PI 318846-3 was the most regenerable genotype, with up to 77% of explants producing one to three shoots per explant. The orientation of the petiole on the nutrient medium was critical; those placed vertically inverted developed multiple shoots. Wounding explants through epidermal peeling with normal horizontal orientation of the explants during incubation also resulted in multiple shoot production (about three shoots per explant). Interference with auxin transport due to explant inversion or wounding may have stimulated increased shoot induction. Chemical names used: 2,4 dichlorophenoxyacetic acid (2,4-D); N-phenyl-N′-1,2,3-thiadiazol-5-ylurea (thidiazuron); N6-(2-isopentenyl) adenine (2iP).
Micropropagation of Six Rockrose (Cistus) Species
Authors: Iriondo José M. , Moreno Carmen , Pérez César
Published: February 2019

Micropropagation methods for six rockrose species (Cistus albidus L., C. clusii Dunal, C. ladanifer L., C. laurifolius L., C. psilosepalus L., and C. salvifolius L.) were established. Cultures, initiated from nodal segments of seedlings, were grown on MS medium, alone, or supplemented with 0.88 μm BAP or 0.93 μm Kin. Multiple shoot formation was obtained after the first subculture (30 days) from which new nodal segments were taken and grown on the same culture medium to maintain proliferation. Shoots obtained at the third subculture were rooted alone or supplemented with different concentrations of IBA. The plantlets of the six species, thereby obtained, were successfully acclimatized to ex vitro conditions. Chemical names used: 6-benzylaminopurine (BAP), indole-3-butyric acid (IBA), 6-furfurylaminopurine (Kin).
Row Spacing Affects Yield of Machine-harvested, Green-mature Southernpeas
Authors: Buckley Blair , Pee Katharine C.
Published: February 2019

An investigation was conducted in 1993 and 1994 to examine the effect of row spacing on yield and pod maturity distribution of machine-harvested, green-mature southernpeas [Vigna unguiculata (L.) Walp]. `Texas Pinkeye Purple Hull' was planted at row spacings of 53, 89, and 107 cm single drilled and 107 cm double drilled. Marketable yield increased linearly as row spacing decreased. A double drill on a standard 107-cm row spacing did not result in higher yield than a single drill. Marketable yield from the double-drilled, 107-cm row spacing was less than yield from the 53-cm spacing. The seeding rate per hectare for the two treatments was the same. In 1993, the mature pod percentage at harvest increased linearly as row spacing decreased. Row spacings as narrow as 53 cm can be used to increase yield of machine-harvested, green-mature southernpeas.
Postharvest Drying of Leyland Cypress, Eastern Red Cedar, and Fraser Fir Christmas Trees
Authors: Hinesley L. Eric , Snelling Layne K.
Published: February 2019

Postharvest drying of Leyland cypress [× Cupressocyparis leylandii (A.B. Jacks. & Dallim.)] branches was intermediate between eastern red cedar (Juniperus virginiana L.) and Fraser fir [Abies fraseri (Pursh) Poir.] in two laboratory experiments. Leyland cypress rehydrated without adverse effect until xylem pressure potential reached –4.0 to –5.0 MPa (shoot moisture content = 60% to 65%). For branches continuously maintained in water, Fraser fir and Leyland cypress kept equally well over 4 weeks of display, but Leyland cypress lasted longer than Fraser fir over 8 weeks. Postharvest keeping quality of Leyland cypress and Fraser fir was better than that of eastern red cedar.
A Restriction Fragment Length Polymorphism Probe for Early Diagnosis of Gender in Asparagus officinalis L.
Authors: Biffi R. , Restivo F.M. , Tassi F. , Caporali E. , Carboni A. , Marziani G.P. , Spada A. , Falavigna A.
Published: February 2019

The use of a sex-linked molecular marker for early sex diagnosis in the dioecious species Asparagus officinalis L. was evaluated. Screening of random genomic probes as a part of a restriction fragment length polymorphism mapping project resulted in the identification of a sex-linked (6.9 cM) marker. The usefulness of this molecular tool was compared to morphological markers for prediction of gender in several genotypes. The level of polymorphism detected by this probe was high, and the level of incorrect sex attribution, as determined by this method, was low (≈7%).
Development of Genic Male-sterile Watermelon Lines with Delayed-green Seedling Marker
Authors: Zhang X.P. , Rhodes B.B. , Baird W.V. , Skorupska H.T. , Bridges W.C.
Published: February 2019

Hybrid seed production can be facilitated by using male sterility coupled with a seedling marker. This research was initiated to combine the ms male sterility and dg delayed-green seedling marker into watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] lines. Male-sterile plants of the male-sterile line G17AB were crossed with plants of delayed-green breeding line Pale90, which has yellow cotyledons and pale-green, newly developed, true leaves. The double-recessive recombinants, male sterile and delayed green, from the F2 population were backcrossed to the male-fertile plants of G17AB. The pedigree method was used for selection in the progenies. The segregation ratios obtained from F2 and BC1F2 populations suggest that the male-sterile and delayed-green traits are inherited independently and that delayed green is inherited as a single recessive nuclear gene. Two male-sterile watermelon lines with delayed-green seedling marker have been developed. These lines will provide a convenient way to introduce male sterility and the delayed-green seedling marker into various genetic backgrounds. These two lines can be used for testing the efficiency of a new, hybrid, watermelon, seed production system.
Isozyme Variation in Cultivars of Purple Loosestrife (Lythrum sp.)
Authors: Strefeler Mark S. , Darmo Elizabeth , Becker Roger L. , Katovich Elizabeth J.
Published: February 2019

Isozyme markers were used to identify several cultivars of purple loosestrife (Lythrum spp.) and interspecific hybrids. There were three zones of activity for phosphoglucomutase (PGM) and phosphoglucoisomerase (PGI) and two zones for malate dehydrogenase (MDH) in purple loosestrife cultivars. Allelic constitution could not be characterized due to the polyploid nature of purple loosestrife and the possibility of intergenic dimerization. Coefficients of genetic similarity were used to estimate the degree of relationship between purple loosestrife cultivars. Cluster analysis indicated that seven cultivars originating from L. salicaria L. were not distinguishable from eight cultivars originating from L. virgatum L., indicating possible limitations of isozyme analysis for cultivar differentiation based on species origin. All but two cultivars (`Morden Gleam' and `Morden Rose') could be distinguished from one another by isozyme phenotype. This result suggests that isozymes may be useful for cultivar fingerprinting if additional isozyme systems could be resolved. `Robert' appeared morphologically heterogeneous, and plants could be differentiated based on isozyme banding patterns. Also, two putative clones of `Stichflamme' (one marketed under its English synonym `Fire Candle') possessed distinct isozyme phenotypes, indicating a lack of clonal integrity.
Tomato Growth in Response to Salinity and Mycorrhizal Fungi from Saline or Nonsaline Soils
Authors: Copeman Ruth H. , Martin Chris A. , Stutz Jean C.
Published: February 2019

Tomato (Lycopersicon esculentum Mill. `Heinz 1350 VF 402') seedlings were inoculated with populations of vesicular–arbuscular mycorrhizal (VAM) fungi collected from saline or nonsaline soil or remained nonmycorrhizal as a control. Plants then were salinated for 8 weeks at 1.0, 2.0, 5.0, or 10.0 dS·m–1 produced by dilutions of 1 m NaCl: 1 m CaCl2 in deionized water. Inoculation with VAM fungi from nonsaline soil enhanced shoot growth, while VAM fungi from saline soil suppressed shoot and root growth. Plants inoculated with VAM fungi from nonsaline soil and non-VAM control plants showed a quadratic increase in leaf Cl– concentration in response to an increased salinity level, whereas plants inoculated with VAM fungi from saline soil showed a linear increase in leaf Cl– concentration. Mycorrhizal-induced growth responses and changes in leaf Cl– concentration were not associated with any apparent alterations in tomato plant P status. Although VAM fungi originating from saline soil did not promote plant growth, reduction in leaf Cl– concentration mediated by these VAM fungi at moderate salinity levels may have beneficial implications for plant survival in saline soil.
Performance of Plug-grown Geranium Seedlings Preconditioned with Nitrogen Fertilizer or Low-temperature Storage
Authors: Kaczperski Mark P. , Armitage Allan M. , Lewis Pamela M.
Published: February 2019

Pelargonium×hortorum L.H. Bailey `Scarlet Elite' seedlings were grown in plugs from seed to transplant size. About 14 days before attaining transplant size, seedlings were exposed to various fertility or temperature regimes (preconditioning treatments), then stored for 1 to 3 weeks at 5C. Seedlings receiving 150 mg N/liter before storage flowered sooner and required less crop time (days to flower – days in storage) than those receiving 0, 75, or 300 mg. Temperature preconditioning at 10 or 15C delayed flowering compared to preconditioning at 20C. Final plant height and dry weight were not adversely affected by varying N levels or temperature during preconditioning. Preconditioning seedlings with 300 mg N/liter resulted in seedling mortality rates up to 16% after 7 days' storage. Low temperature or fertility were not effective preconditioning treatments. Best results were attained by preconditioning seedlings with 150 mg N/liter.
Root Medium Carbon Dioxide and Oxygen Partial Pressures for Container-grown Chrysanthemums
Authors: Argo William R. , Biernbaum John A. , Fonteno William C.
Published: February 2019

Medium CO2 and O2 partial pressures were measured at three locations [3.8 (top layer), 7.5 (middle layer), and 10.3 (bottom layer) cm below the rim] in 15-cm-tall pots containing flowering chrysanthemums [Dendranthem×grandiflorum (Ramat.) Kitamura] grown in one of three root media. Average ambient medium CO2 and O2 partial pressures were 63 Pa and 21 kPa, respectively, and were similar in the three sampled layers in root media with an average moisture content of 50% to 60% of container capacity. Within 10 minutes after a drip-irrigation application of well water containing a titratable alkalinity to pH 4.5 of 320 mg CaCO3/liter, the partial pressure of medium CO2 increased to ≤1600 Pa and medium O2 decreased to 20.5 kPa in the top and middle layers of the pot. With subirrigation, medium CO2 partial pressures increased to ≤170 Pa and medium O2 remained at 21 kPa. When reverse-osmosis purified water (titratable alkalinity to pH 4.5 of <20 mg CaCO3/liter) was used instead of well water, the large increase in medium CO2 did not occur, indicating that the bicarbonate alkalinity in the irrigation water was the source of CO2. The high medium CO2 partial pressure measured after irrigation was not persistent; within 180 minutes, it returned to levels averaging 45% higher (100 Pa) than that measured before the irrigation. Medium O2 also had returned to ambient levels 180 minutes after the irrigation.
Growth Regulation of Bahiagrass (Paspalum notatum Fluegge) with Imazaquin and AC 263,222
Authors: Goatley J. Michael , Maddox Victor L. , Watkins Robert M.
Published: February 2019

Research was conducted over 2 years to evaluate efficacy of various levels and combinations of imazaquin and AC 263,222 for growth regulation of unimproved bahiagrass (`Pensacola') turf. Imazaquin at 0.42 kg·ha–1 caused only slight bahiagrass discoloration in all trials and reduced seedhead count (as compared to the nontreated control) by ≥80% for 8 weeks after treatment (WAT) following a July 1992 application. AC 263,222 at 0.042 or 0.056 kg·ha–1 applied in late May or June provided 100% seedhead control through 8 WAT. However, AC 263,222 applied in July 1992 and Aug. 1993 at 0.056 kg·ha–1 resulted in unacceptable discoloration through 8 WAT. AC 263,222 at 0.014 or 0.028 kg·ha–1 provided ≥90% seedhead control with only minimal discoloration following applications in July or Aug. 1993, indicating that lower rates of AC 263,222 provided acceptable seedhead control of bahiagrass during times when growth was slowed due to moisture stress. Chemical names used: (±)-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-methyl-3-pyridinecarboxylic acid (AC 263,222); 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid (imazaquin).
Influence of Stock Plant Carbohydrate and Nitrogen Content on Rooting Stem Cuttings of Hedged Loblolly Pine
Authors: Rowe D.B. , Blazich F.A. , Pharr D.M. , Wise F.C.
Published: February 2019

Containerized, 2.5-year-old, hedged stock plants of four, full-sib families of loblolly pine (Pinus taeda L.) were fertilized daily with a complete nutrient solution containing 10, 25, 40, 55, or 70 ppm N, which resulted in a range of stock plant soluble carbohydrate (SCHO) and tissue N levels. SCHOs included myo-inositol, glucose, fructose, sucrose, and raffinose. Nitrogen concentrations and SCHO: N ratios ranged from 1.23% to 2.24% and 16:1 to 29:1, respectively. Softwood cuttings were taken in May and July 1995 and placed under intermittent mist. May cuttings rooted at significantly greater percentages than July cuttings (60% vs. 34%). Averaged over all N treatments, the best rooting family (56%) contained the highest tissue concentration of SCHOs (465 mg·g–1 dry weight) and had the highest SCHO: N ratio (26:1), whereas, the poorest rooting family (39%), exhibited the lowest level of SCHOs (357 mg·g–1 dry weight) and the lowest SCHO: N ratio (21:1). Rooting exhibited a quadratic response in regards to N fertilization levels and tissue SCHO concentrations. For both rooting trials, maximum rooting (83%) was noted for May cuttings taken from stock plants of one family fertilized with 40 ppm N, which corresponded to a tissue N concentration of 1.95% and a SCHO: N ratio of 22:1.
Time-lapse Video Photography: A Low-tech Way to Make Plants Dance
Authors: Wien H.C. , Sloan R.J.
Published: February 2019

The growth processes of most horticultural crops are too slow to be visually interesting to students. Time lapse photography has been used for years to speed up the action and make plants “come alive.” With the advent of video technology, time lapse techniques have become convenient, easy, and affordable. The system which we have found satisfactory consists of a time lapse video cassette recorder, linked by optical fiber cable to a closed circuit color video camera in a ventilated housing. Typically, the camera has been set up in a greenhouse compartment, monitoring growth processes of vegetable crops, and linked by cable to the VCR in an office 80 m away. Equipment costs with one camera are less than $3000. Two cameras can be set up to do comparative growth studies, with two images side-by-side, using a screen splitter. Costs of the latter system is about $4500. Growth processes such as cabbage head formation, curd growth in cauliflower, and weed-crop competition of mustard and peas have been the subjects so far. The technique lends itself to increasing the visual impact of teaching, and gaining a better understanding of plant growth processes in research.
Efficacy of Endogenous Satellite Expression to Confer Resistance to CMV in Satellite Transgenic Tomato under Field Conditions
Authors: Stommel John R. , Tousignant Marie E. , Wai Thanda , Kaper Jacobus M.
Published: February 2019

Viral satellite RNA associated with cucumber mosaic virus (CMV) is know to modulate CMV symptomology. Virulent CMV associated RNA 5 (CARNA 5) satellites may intensify crop disease. Naturally occurring variants of these satellites, however, attenuate CMV symptoms. Satellite transgenic tomato plants expressing the S-CARNA 5 or 1-CARNA 5 ameliorating forms of the satellite were evaluated under simulated CMV epidemic conditions in USDA–APHIS approved field trials. Trials conducted at Beltsville, Md., in 1994 and 1995 demonstrated that CMV can be effectively controlled under field conditions in satellite transgenic plants. Yields of transgenic lines infected with CMV were 50%–65% greater than that of non-transgenic infected controls. Yields of noninfected transgenic lines ranged from 5% greater than, to 33% less than, noninfected nontransgenic controls. Expression of CARNA 5 in inoculated transgenic plants greatly reduced CMV foliar symptoms and virus titers when compared to inoculated control plants. Levels of CARNA 5 were detected at varying levels in infected transgenic plants throughout the growing season. Virus or satellite was not detected in samples collected from tomato border plants and weeds growing inside and outside a nonhost crop border surrounding the test plot. Field tests conducted in 1996 will evaluate transgenic tomato plants with a double construct coding for the CMV coat protein gene and 1-CARNA 5 satellite.
Effect of UV-reflective Mulches on Tomato Yields and on the Silverleaf Whitefly, Bemisia argentifolii (Bellows & Perring)
Authors: Csizinszky A.A. , Schuster D.J.
Published: February 2019

Field studies were conducted for three seasons, Fall 1994, Spring 1995, and Fall 1995 on the effect of UV-reflective films (mulches) on fruit yields and on the silverleaf whitefly [Bemisia argentifolii (Bellows and Perring)] of staked, fresh-market tomatoes (Lycopersicon esculentum Mill). The UV-reflective mulches were metallized aluminum (ALU) and painted aluminum (PAL) on either black or white plastic film. The AL and SL 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 25 cm from the mulch surface was measured on the ALU without white painted band or on PAL on white or black mulch with white painted band. Lowest energy was reflected from the white or black controls. Whitefly populations in the fall were lower on the ALU than on the PAL mulches. In the spring, when whitefly populations were low, number of whiteflies on tomato leaves were similar with all treatments. The proportion of plants with symptoms of the silverleaf whitefly transmitted tomato mottle virus (TMoV) were highest on controls. Yields in the fall were similar with UV-reflective or with white mulch. In the spring, fruit size and marketable yields were greater (P < 0.05) on plants with PAL on white plastic film without black band than on black control.