bluuebunny/crossref_metadata_2025 huggingface dataset:
NITROGEN USE EFFICIENCY IN SWEETPOTATO
Authors: Pecota Kenneth V. , Collins Wanda W.
Published: February 2019

Eight clones of sweetpotato [Ipomaea batatas (L.) Lam.] at five N levels in 1992 and five clones at three N levels in 1993 were evaluated for genotypic variation in N use efficiency [NUE (yield/unit N fertilizer applied)], uptake efficiency (N accumulated/unit N fertilizer applied), and utilization efficiency (yield/N accumulated). There were significant genotypic differences for all NUE components and the variables used for calculation. When total marketable yield was used in calculating NUE, utilization efficiency was always more important than uptake efficiency in accounting for NUE variation. Regression equations developed from 1992 NUE components and selected non-N variables used to calculate them ranked the 1993 NUE components correctly when averaged over all clones. Uptake efficiency could be predicted by biomass; utilization efficiency by total marketable yield.
SWEETPOTATO PLANT BED FERTILIZATION
Authors: Sloan R.C. , Thompson P.G. , Main J.L.
Published: February 2019

Eight plant bed fertilizer treatments (N–P–K) were evaluated for the effect on plant production and sweetpotato yield. The treatments ranged from 0–0–0 to 450–450–450 lb/ac. `Beauregard' roots were bedded. After the first plant cutting, 50 lb/ac 34–0–0 was applied to half of the beds. For the second cutting, the 0N–0P–0K treatment without additional N produced plants with less green weight compared to the other treatments; there were no differences between the other 15 treatments. For the first plant cutting, 150–150–150 and 150–300–450 lb/ac produced plants with less green weight compared to 0–0–0, 75–150–300, 300–450–600, and 450–450–450 lb/ac. There were no differences in sweetpotato yield due to plant bed fertilization.
Relative Water Content and Rooting of Subirrigated Stem Cuttings in Four Environments without Mist
Authors: Graves William R. , Zhang Hongyi
Published: February 2019

Air temperature and photosynthetically active radiation (PAR) effects on relative water content (RWC), rooting percentage, root count, and root mass of unmisted, subirrigated stem cuttings of two taxa were determined. Leaf RWC of `Charm' chrysanthemum [Dendranthema ×grandiflorum (Ramat.) Kitamura] decreased until roots initiated and then increased, was lower for cuttings at 23 °C photoperiod/14 °C dark than for cuttings at 31 °C photoperiod/22 °C dark, and was lower at 193 than at 69 μmol·m–2·s–1 PAR. Neither temperature nor PAR affected leaf RWC of `Dollar Princess' fuchsia (Fuchsia ×hybrida Hort. ex Vilm.), which increased linearly before and after root initiation. Rooting percentage and root count were higher with photoperiods at 31 °C than at 23 °C for chrysanthemum after 7 days and for fuchsia after 10 days. Although all cuttings of both taxa had rooted after 14 days, root dry mass was higher with photoperiods at 31 °C than at 23 °C regardless of PAR for fuchsia and at 69 μmol·m–2·s–1 PAR for chrysanthemum. Propagators wishing to use subirrigation instead of mist, fog, or enclosure can minimize the decline in leaf RWC before root initiation and increase the number and dry mass of roots of chrysanthemum by using 69 μmol·m–2·s–1 PAR and a 31 °C photoperiod/22 °C dark cycle. Root dry mass of fuchsia also can be increased by the use of high temperature, but differences in rooting were independent of changes in leaf RWC.
High-pressure Sodium Radiation during Off-peak Nighttimes Increases Cut Rose Production and Quality
Authors: Hopper Douglas A.
Published: February 2019

One-year-old plants of four cut rose (Rosa hybrida L.) cultivars were grown under either natural or supplemental irradiance for 4 months during the winter in Colorado. Supplemental irradiance with high-pressure sodium (HPS) lamps was supplied at 100 μmol·m–2·s–1 for 10 h each night during off-peak electrical use periods. Total cut flower yield, stem length, and fresh weight of individual flowers were recorded. The number of flowers produced and fresh weight increased for all cultivars under the supplemental irradiance treatment. Flower count, stem length, and fresh weight showed significant differences among the four 4-week production periods; production differences were promoted through pinches of two stems per plant to time for holiday peaks. When production was highest, stem length and fresh weight were lower, most likely due to redistribution of the limited carbohydrate pool during the winter.
Source Variation in Physical and Chemical Properties of Coconut Coir Dust
Authors: Evans Michael R. , Konduru Sreenivas , Stamps Robert H.
Published: February 2019

Physical properties differed significantly among five Philippine-produced coconut (Cocos nucifera L.) coir dust sources. Bulk densities ranged from 0.04 to 0.08 g·cm–3. Air-filled pore space, water-filled pore space, and total pore space ranged from 9.5% to 12.6%, 73.0% to 80.0%, and 85.5% to 89.5% (v/v), respectively. Total solids accounted for 10.5% to 14.5% of total volume, and water-holding capacities ranged from 750% to 1100% of dry weight. Significant differences existed in particle size distribution, with the largest differences occurring for particle sizes <8.0 mm and 0.25 to 0.50 mm in diameter. Chemical properties were determined for 12 sources from the Philippines, Sri Lanka, or Indonesia. The pH and electrical conductivities ranged from 5.6 to 6.9 and 0.3 to 2.9 mS·cm–1, respectively, and were significantly different among sources. No significant differences occurred among samples with respect to Fe, Mn, Zn, B, Cu, NH4-N, and Mg concentrations. Coir dust samples contained Fe, Mn, Zn, B, and Cu at 0.01 to 0.07 mg·L–1. The levels of NH4-N and Mg were 0.1 to 0.2 and 1.0 to 7.4 mg·L–1, respectively. Significant differences occurred between sources for Ca, Na, and NO3-N, with levels (mg·L–1) ranging from 1.0 to 24.3, from 22.3 to 88.3, and from 0.4 to 7.0, respectively. The widest ranges occurred in K (19 to 948 mg·L–1) and Cl (26 to 1636 mg·L–1). Sources differed with respect to cation exchange capacities, with values ranging from 38.9 to 60.0 meq/100 g.
Postharvest Infection of Highbush Blueberries following Contact with Infested Surfaces
Authors: Cline W.O.
Published: February 2019

The effects of inoculum, surface wetness, and stem scar on postharvest fungal infection of highbush blueberry (Vaccinium corymbosum L.) fruit were evaluated by exposing berries of the cultivars Bluechip (small, dry stem scar) and Blueray (large, wet stem scar) to infested and noninfested surfaces under wet or dry conditions. Rots caused by Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. and Alternaria tenuissima (Kunze:Fr.) Wiltshire were evaluated. Field-harvested berries stored for 7 days at 21 °C resulted in baseline infection levels of 1.5% (`Bluechip') and 18.7% (`Blueray') for C. gloeosporioides, and 10.1% vs. 28.9%, respectively, for A. tenuissima. Wet stem scars, infestation of handling surfaces, and addition of moisture were all responsible for increasing postharvest rots; however, most of the significant increases in rots occurred with a combination of two or more of these factors.
Importance of Collard and Kale Genotype for Winter Production in Southeastern United States
Authors: Farnham M.W. , Garrett J.T.
Published: February 2019

Winter production of collard and kale (Brassica oleracea L. Acephala Group) in the southeastern United States is limited by the tendency of these leafy green vegetables to bolt following vernalization. Collard and kale cultivars, landraces, and breeding lines were tested in four winter environments from 1992 to 1995 to determine differences among all included entries for winter production and tendency to bolt in a cold season environment. Essentially all entries survived the conditions of four winter environments. However, whether an entry reached harvest size depended on its date of 50% bolting. Collard typically bolted earlier than kale. Most kale entries reached a marketable size before bolting, while only the collard cultivars `Blue Max' and `Champion' and landraces G. Summersett and Mesic Zero consistently did the same. Several entries, for example, `Squire' kale and G. Summersett collard, usually did not bolt. Results of this research indicate that significant genetic control of the long-standing (delayed bolting) phenotype is present in collard and kale. Successful winter production of these cole crops can be better ensured by using a long-standing genotype.
Variation in Allium spp. Damage by Onion Maggot
Authors: McFerson James R. , Walters Thomas W. , Eckenrode Charles J.
Published: February 2019

Nearly 350 germplasm accessions representing 25 Allium species were evaluated for damage by onion maggot (OM) [Delia antiqua (Meigen)] in field experiments in 1989. In 1990, 188 additional accessions and breeding lines were evaluated, and 36 entries from the 1989 evaluation were re-evaluated. In both years, there were no significant differences in OM damage to seedlings among accessions within the species tested. However, differences among species were highly significant. Allium cepa L. (bulb onion) seedlings had consistently high OM damage. Species with significantly less seedling damage than A. cepa included: A. altaicum Pall., A. angulosum L., A. galanthum Kar. & Kir., A. pskemense B. Fedtsch., A. scorodoprasum L., A. ampeloprasum L. (leek), A. fistulosum L. (bunching onion), A. schoenoprasum L. (chive), and A. tuberosum Rottl. ex Spr. (garlic chive). Some species sustaining minimal damage as seedlings were nonetheless heavily damaged as mature plants by a later generation of OM. Allium cepa cultivars that were well-adapted to local conditions were heavily damaged as seedlings, but their bulbs were less damaged than those of poorly adapted A. cepa germplasm. Allium ampeloprasum seedlings and mature plants sustained low injury throughout both growing seasons.
Solarization for Weed Control in a Short-season Climate
Authors: Robbins Jo Ann , Blackburn Carol
Published: February 2019

A solarization site was established on the grounds of the Sawtooth Community Garden south of Ketchum, Idaho, in 1995. Feasibility of solarization for weed control was determined in a region of sunny, warm days and cool nights. Elevation of the site was 1829 m, with a growing season of 90 days. Treatments of double and single layers of clear and IRT plastic were applied 23 May 1995. These solarization treatments were compared to hand-hoeing, glyphosate sprays, and no control. Highest soil temperatures were reached under the double clear plastic, where daily peak temperatures ranged from 19 to 46C. Plastic treatments were removed on 30 Aug. 1995. Weed growth and growth of peas, green beans, carrots, and beets were recorded during the summer of 1996. Weed growth on 14 June 1996 ranged from 0.3 to 0.8 weeds/m2 in the solarization, hand-hoe, and glyphosate treatments and was 22.4 weeds/m2 in the no control treatment. On 20 Aug., weeds/m2 ranged from 1.4 to 2.0 in the solarization, hand-hoe, and glyphosate treatments and was 20.4 weeds/m2 in the no control treatment. At both dates there was no significant differences between weed control treatments, and any weed control method was significantly better than no control. Weight per plant of beets and beans was no different across all treatments. Carrot and pea plants were smaller in the no control treatments, and some variable differences were noted between weed control treatments. Results indicate that solarization in short-season, cool climates will result in little to no advantage over hand-hoeing or herbicide control of weeds, and no subsequent differences in crop growth can be expected.
Effects of Girdling by the Threecornered Alfalfa Hopper on Host Plant Growth and Physiology
Authors: Brodbeck Brent V. , Stavisky Julieanne , Andersen Peter C. , Funderburk Joseph E.
Published: February 2019

The threecornered alfalfa hopper, Spissistillus festinus (Say), is a major pest to production of a wide variety of crops. Herbivory by this insect is often highly detrimental because of girdling of petioles and shoots. Although girdling by this hopper has been recorded on a variety of hosts, the physiological effects of girdling have been examined primarily on one host (Glycine max). We examined the physiological effects of girdling by four densities of hoppers on Arachis hypogaea (L.) cv. Florarunner. Densities of 0, 2, 4, and 6 hoppers per plant were maintained for a 1-week period on peanuts grown in cages in a greenhouse. Effects of hopper herbivory on growth (shoot elongation and increases in plant dry weight) and whole-plant chemistry (carbon, nitrogen, and amino acid analysis) were determined at the end of the 1-week feeding experiments, and again at 2-week intervals until maturation of plants. Differences in plant growth or chemistry were not apparent at the conclusion of the feeding experiment. However, plants subjected to the highest rates of herbivory showed pronounced deleterious effects 2 to 6 weeks after girdling had occurred. Mean shoot growth was decreased by nearly 40% and plant dry weight was reduced by roughly 20%. Foliar nitrogen concentrations were also significantly reduced; peanuts subjected to high rates of herbivory contained 30% less foliar protein that control plants. This delayed response to girdling appeared to be in part attributed to increased rates of shoot and petiole breakage well after girdling occurs. Girdles became more brittle as shoots matured and hardened with maturity. Effects of girdling may be particularly detrimental to yield, as effects are most pronounced as plants are entering the reproductive stage.
Pot Sunflower Growth and Flowering Responses to Foliar Applications of Daminozide, Paclobutrazol, and Uniconazole
Authors: Whipker Brian E. , Dasoju Shravan
Published: February 2019

Plant growth retardant (PGR) foliar spray treatments (mg•liter–1) of daminozide at 1000 to 16,000; paclobutrazol from 5 to 80; and uniconazole from 2 to 32 were applied to `Pacino' pot sunflowers (Helianthus annuus) to compare their effectiveness at chemical height control. When the first inflorescence opened, the number of days from seeding until flowering, total plant height measured from the pot rim to the top of the inflorescence, inflorescence diameter, and plant diameter were recorded. Total plant height, plant diameter, inflorescence diameter, and days until flowering were significant for the PGR treatment interaction. Marketable-sized plants grown in the 1.2-liter pots were produced with uniconazole concentrations between 16 and 32 mg•liter–1 or with daminozide concentrations between 4000 and 8000 mg•liter–1. Paclobutrazol foliar sprays up to 80 mg•liter–1 had little effect and higher concentrations or medium drench treatments should be considered.
Mapping of the Frl Locus Conferring Resistance to Fusarium oxysporum f.sp. radicis-lycopersici(FORL) in Tomato and Identification of RAPD Markers Linked to a New Source of Resistance
Authors: Fazio Gennaro , Stevens Mikel R. , Scott John W.
Published: February 2019

Fusarium crown and root rot of tomato is caused by Fusarium oxysporum f.sp. radicis-lycopersici (FORL). A single dominant gene (Frl) derived from L. peruvianum L. (Mill.) was previously identified as a useful source of resistance to FORL. The objective of this research was to identify molecular markers linked to Frl and RAPD markers linked to a new source of resistance to FORL being developed from L. pennellii (Corr.) D'Arcy accession LA1277. The DNAs of resistant (Frl) and susceptible breeding lines were screened for polymorphisms using 1200 RAPD primers. Of these, only 104 yielded polymorphisms between the resistant and susceptible lines. These polymorphisms were then tested on four additional tomato lines homozygous for Frl and an additional pair of near-isogenic lines developed by Dr. Laterrot. Only 13 primers still produced consistent polymorphisms between all resistant and susceptible lines. Four of these polymorphisms (RAPD 116, 194, 405, 655) were determined to be linked to Frl in an F5 segregating population using an inoculation procedure devised to clearly differentiate susceptible and resistant plants. The linkage between ah and Frl reported by Laterrot [Laterrot and Moretti Tomato Genet. Coop. Rep. 45:29 (1995)] places Frl on the long arm of chromosome 9 of the tomato genome. The parent lines were also tested with a sequence tagged site (STS) of TG101, which is tightly linked to Tm2a [Young et al., Genetics 120:579-585 (1988)] and yielded polymorphic codominant bands. This STS was also tested on the F5 segregating population and it cosegregated with the resistance and with the RAPD markers. Breeding of the second source of resistance is still in progress. The DNAs of 30 resistant BC1F5 plants derived from LA1277 were bulked and compared to the recurrent susceptible parent DNA using 800 RAPD primers. Of the 800 RAPD primers, 72 yielded consistent polymorphisms. None of the 72 primers were found to produce polymorphisms similar to those identified from the analysis of Frl, thus suggesting the possibility different genetic control being involved with FORL resistance from LA1277.
Inheritance of Ear Resistance to European Corn Borer in Sweet Corn
Authors: Warnock Daniel F. , Davis David W.
Published: February 2019

European corn borer, Ostrinia nubilalis Hübner, is an economic pest of sweet corn. Consumer demand for high-quality, insect-free produce with minimal pesticide residue necessitates exploitation of various control options. Ear feeding resistance could reduce insecticide inputs. The inheritance of ear feeding resistance and silk channel length in the F1 derived from a diallel cross (Griffing's model I, method 2) of eight breeding stocks describing a wide range of feeding resistance was investigated in field experiments. Feeding damage, based on a 1 (no damage) to 9 (>10% ear damage) visual rating scale, and silk channel length of ears that had been manually infested at the ear tip with O. nubilalis were recorded. A significant (P ≤ 0.05) year by location interaction was found for ear feeding damage and silk channel length. Genotype ear feeding damage and silk channel length differences were significant (P ≤ 0.01) beyond genotype by environment (year and location) interactions. Mean feeding damage ranged from 2.5 (parents 1 × 7) to 8.8 (parent 2) and mean silk channel length ranged from 1.9 cm (parents 2 × 7) to 9.0 cm (parent 3). Ten of the 28 possible crosses (reciprocals combined) and 1 parent were classed as resistant (damage rating < 3.0). Eleven crosses, including all 7 involving parent 2, and 2 parents were susceptible (damage rating > 4.0). Pearson's correlation analysis indicated lower damage levels were weakly to moderately associated with increased silk channel length for both parents (r = –0.18) and progeny (r = –0.44). The general combining ability (GCA) component was significant (P ≤ 0.01) for ear feeding damage, suggesting additive effects control ear feeding damage. GCA and specific combining ability (SCA) effects did not account for silk channel length variability, suggesting strong environmental influences. Improved ear feeding resistance should be possible via recurrent selection with recombination.
Intraspecific Variations of Epimedium koreanum by Randomly and Specifically Amplified Polymorphic DNA Markers
Authors: Lim Hak-Tae
Published: February 2019

Randomly and specifically amplified polymorphic DNA banding patterns based on polymerase chain reaction (PCR) analysis were used to assess the intraspecific genetic variations and relationships within Epimedium koreanum populations. A collection of 21 individuals were classified as different accessions by morphological characters such as leaflet number, shape of leaf base, cauline length, plant height, and leaf area. PCR amplification using 12 primers out of 62 [60 random (10-mer) primers, one 15-mer primer (M13 core sequence), and (GGAT)4] resulted in 89 amplified DNA fragments with polymorphisms (80.9%) in all of the tested plants. Similarity indices between accessions were computed from PCR data, and genetic relationships among intraspecific variations were closely related at the levels ranging from 0.66 to 0.93. These DNA data were not matched well with those of morphological characters because they were divided into two major groups at the similarity coefficient value of 0.74. Primers (VII, VIII) gave rise to monomorphic bands in all of examined plants, but specific primers (M13 core and (GGAT)4 sequences) were found to be very valuable molecular markers to evaluate the interspecific variations in Epimedium koreanum.
Enhanced Degreening of Apple Fruit by Jasmonates
Authors: Fan Xuetong , Mattheis James P.
Published: February 2019

Airborne methyl jasmonate (MJ) can modulate apple fruit ripening, including the degreening process. Degreening of `Fuji' and `Golden Delicious' apples by jasmonates [jasmonic acid (JA) and MJ] in aqueous solution was investigated. JA and MJ applied by dipping apples in solutions of jasmonates for 2 min enhanced degreening during ripening at 20C. MJ was more effective at promoting degreening compared to JA. The minimum concentration of jasmonates required to promote significant degreening during the 2-week ripening period was 1 mM. Degreening of jasmonate-treated apples ripened at 4C progressed slower compared to apples ripened at 20°C. JA stimulated apple fruit ethylene production at concentrations as low as 10 μM. Jasmonates at 1 or 10 mM were more effective at accelerating the degreening process compared to 0.35 or 3.5 mM ethephon. Firmness, soluble solids content, and titratable acidity of `Fuji' apples were not significantly affected by jasmonate treatments. Peel injury occurred on apples treated with 10 mM JA or 3.5 mM ethephon.
Effect of Different Concentrations of Plant Growth Regulators on in Vitro Propagation of Curcuma roscoeana Wall.
Authors: Sotthikul Chamchuree , Apavatjrut Pimchai
Published: February 2019

Curcuma roscoeana Wall. is a tuberous perennial plant with tuberous rhizomes. It is an endangered species. In nature, it has a very low rate of multiplication. Propagation of C. roscoeana in vitro was done by culturing 0.5 × 1.0-mm shoot tips from young buds onto modified Murashige and Skoog (MS)+ 0.25 mg/L kinetin. Stem explants 10.0 mm in size, measured from the base of the plantlets longitudinally cut in half, were used in the experiments. The first experiment was done by varying the concentration of both kinetin and NAA, in MS liquid medium, at 0–8.0 mg/L and 0–0.05 mg/L, respectively. There were no significant differences of kinetin and NAA concentrations on the number of plantlets obtained. The 0.5-mg/L kinetin treatment gave the highest yield in number of new plantlets (3.1 plantlets/cultured explant). In the second experiment, various concentrations of BAP from 0 to 8.0 mg/l were tested. 2.8–3.7 plantlets were formed in the media with 0.05–2.0 mg/L of BAP. The most-suitable concentration of BAP was at 1.0 mg/L, providing 3.7 plantlets/cultured explants. Kinetin or BAP alone could be used in MS medium for rapid clonal propagation of C. roscoeana. The rooted plantlets could be successfully transferred into growing pots. Acknowledgement: The studies were supported in part by The King's Initiative Centre for Fruit and Flower propagation and Development, Ban Rai, Chiang Mai.
Effect of Meristem Position and Medium on in Vitro Meristem Culture of Alstroemeria
Authors: Chiari Alessandro , Bridgen Mark P.
Published: February 2019

Meristems from three different positions were excised from in vitro plants of Alstroemeria genotype A30. Explants were removed from the most-distal vegetative shoot apical meristems, rhizome tip apical meristems, and rhizome tip axillary meristems. Meristems were cultured on four different media to compare the effect of meristem position and medium on the ability to produce Alstroemeria rhizomes from meristems. The meristem culture media were Murashige & Skoog salts plus 8.39 μM pantothenic acid, 1.19 μM thiamine, and 0.55 mm myo-inositol (MSM), MSM plus 8.88 μM of 6-benzylaminopurine (BA), MSM plus 8.88 μM BA, and 0.72 μM gibberellic acid (GA3), and MSM plus 0.72 μM GA3. Meristems that were removed from the vegetative shoot apices did not develop rhizomes on any medium. Rhizome tip apical meristems developed less than 10% rhizomes when subcultured on media containing BA and GA3. However, rhizome tip axillary meristems developed rhizomes on all media with best results achieved when the medium was supplemented with BA.
Yield Effects and Economic Comparison of Using Fresh or Composted Dairy Manure Amendments on Double-cropped Vegetables
Authors: Roe Nancy E. , Cornforth Gerald C.
Published: February 2019

In many areas, dairies and other concentrated animal operations must modify their waste handling systems. Utilization of locally produced manures by vegetable production operations may increase crop yields while preventing discharge of potentially polluting nutrients into waterways. Composting is often recommended to stabilize nutrients, lower the volume of manure, and produce a product that may control some plant diseases. However, composting has costs in time and equipment, so some growers prefer using uncomposted manure. Dairy manure compost at 22 (LC), 45 (MC), or 90 (HC) t·ha–1 or dairy lot scrapings at 45 t·ha–1 (FM) were tilled into soil before seeding a dryland cantaloupe (Cucumis melo L.) crop. All plots, including an unamended control (UC), were fertilized with a total of 23N–14P–0K (kg·ha–1). After removal of the cantaloupe in late summer, drip irrigation was added, broccoli (Brassica oleracea var. botrytis Mill.) seedlings were transplanted into the identical plots, and 112N (kg·ha–1) was sidedressed. Cantaloupe yields from FM, LC, MC, HC, and UC plots were 5.4, 3.4, 2.1, 4.5, and 1.5 t·ha–1, respectively. Broccoli yields from FM, LC, MC, HC, and UC plots were 4.1, 3.6, 4.4, 4.1, and 2.2 t·ha–1, respectively. All rates of compost or manure increased yields of cantaloupe, and the subsequent broccoli crop. Use of the manure resulted in highest increase in potential net income from sales of cantaloupe and broccoli.
Phases of Flower Development in Opium Poppy under Various Temperatures
Authors: Wang Z. , Acock M.C. , Acock B.
Published: February 2019

Flower development in opium poppy (Papaver somniferum L.) has been divided into four phases from emergence to anthesis, which mark changes in its sensitivity to photoperiod: a photoperiod-insensitive juvenile phase (JP), a photoperiod-sensitive inductive phase (PSP), a photoperiod-sensitive post-inductive phase (PSPP), and a photoperiod-insensitive post-inductive phase (PIPP). To predict flowering time under field conditions, it is essential to know how these phases are affected by temperature. Plants were grown in artificially lit growth chambers and received three temperature treatments: 15/10, 20/15, and 25/20°C in a 12-hr thermoperiod. Plants were transferred within each temperature regime from a non-inductive 9-hr to an inductive 16-h photoperiod or vice versa at 1- to 4-day intervals to determine the durations of the four phases. Temperature did not affect the durations of the first two phases (i.e., JP lasted 3 to 4 days and PSP required 4 to 5 days). The most significant effect of temperature was on the duration of PSPP, which lasted 28, 20, and 17 days at 15/10, 20/15, and 25/20°C, respectively. The temperature effect on PIPP was small (maximum difference of 3 days for treatments) and the data too variable to indicate a significant trend. Our results indicate that PSPP is the only phase that clearly exhibits sensitivity to temperature.
In Vitro Multiplication of Two Genotypes of Asparagus (Asparagus officinalis L.)
Authors: de L. Fortes Gerson R. , Müller Nilvane T.G. , Faria Janine T.C. , Andrade Luciana B. , de F. Oliveira Marisa
Published: February 2019

Asparagus is a vegetable that presents an increase in yield when propagated by meristem culture. On the order hand, the rooting phase in asparagus is greatly affected by the previous phase, i.e,. multiplication. This species presents a better rooting performance when callus is formed at the shoot base. So, the aim of this work was to evaluate treatments during the multiplication phase, which also leads to callus formation at the shoot base. The initial explants came from shoots being cultivated in vitro. It was tested kinetin at: (0.0, 0.5, 1.0, 1.5, and 2.0) μM; ancymidol at (0.0 and 0.5) μM and NAA at (0.0 and 0.5) μM for both genotypes, which were cultured in a MS medium added to sucrose (30 g·L–1), agar (6.0 g·L–1) and myo-inositol (100.0 m g·L–1). Shoots bearing two buds were inoculated in 10-ml test tubes and placed in a growth room for 30 days when they were evaluated. The addition of kinetin significantly improved the number of buds and at 1.3 μM this growth substance presented the best results as number of shoots is concerned. NAA application promoted a negative effect on spear bearing. The addition of ancymidol in this phase did not improve the bud multiplication. It was shown that clone M14 performed better than the hybrid cv. Deco as multiplication is concerned.
Growth and Performance of Five Disease-resistant Apple Cultivars on M.27 EMLA, M.26 EMLA, and Mark Rootstocks
Authors: Schupp J.R. , Koller S.I.
Published: February 2019

The growth, precocity, yield, and fruit size of `Liberty', `NY 75414-1', `NY 74828-12', and `NY 65707-19' on M.27 EMLA, M.26 EMLA, and Mark rootstocks, and `McShay' on M.26 EMLA and Mark, were compared. `Liberty', `McShay', and `NY 74828-12' trees were larger than `NY 75414-1', while `NY 65707-19' trees were the smallest. Among rootstocks, trees on Mark were larger than trees on M.26, while trees on M.27 were the smallest. There were no interactions between cultivar and rootstock on tree growth in this study. `NY 74828-12' produced the most flower clusters in the 3rd and 4th years of the study, and `NY 65707-19' the least. In 1993, trees on Mark had more flowers than those on M.26, while trees on M.27 had the fewest flower clusters. `Liberty', `NY 75414-1', and `NY 74828-12' produced higher cumulative yield than `McShay' and `NY 65707-19'. Trees on Mark had higher cumulative yield than M.26, while trees on M.27 produced the smallest yields. Fruit size was greatest for `NY 65707-19' and smallest for `NY 74828-12'. Trees on M.27 produced smaller-sized fruit than trees on M.26 or Mark. `NY 75414-1' had moderate vigor, high precocity, yield, and yield efficiency, with acceptable fruit size. `NY 74828-12' also performed well in this trial, but possesses Vm resistance to apple scab, not Vf, and is unlikely to be named. Based on tree vigor, percocity, yield, and fruit size, `Liberty' and `NY 75414-1' have the best potential for commercial production among DRCs in this trial. Mark rootstock produced the largest trees with the highest yields, and was superior to M.26 as a rootstock for the DRCs in this study.
Abscisic Acid as a Defoliant for Deciduous Fruit Tree Nursery Stock
Authors: Larsen Fenton E , Higgins Stewart S.
Published: February 2019

Artificial defoliation of deciduous fruit tree nursery stock is often necessary so that plants can be dug early enough to escape inclement fall weather. In this research, we assessed the efficacy of abscisic acid (ABA) as a defoliant. ABA was applied as a foliar spray at one of three concentrations—500, 1000, or 2000 ppm a.i. Trees were sprayed either once or twice for a total of six chemical treatments, plus untreated controls. The defoliation and growth responses of eight cultivars were evaluated with the cooperation of commercial nurseries in Washington State. While all treatments caused significantly greater defoliation than was observed in untreated trees, ABA at 500 ppm applied once or twice, or 1000 ppm applied only once, was generally sufficiently effective only on `Bartlett', `Gibson Golden Delicious', and `Law Red Rome', but not on `Imperial Gala', `Scarlet Spur Delicious', `Granny Smith', `Braeburn', or `Red Fuji'. Single or double applications of 2000 ppm or double applications of 1000 ppm often produced faster defoliation than double applications of 500 ppm, but defoliation was not always superior after 4 weeks. No pre-digging field damage was noted, but some treatments appeared to reduce trunk diameter increase after replanting, with no consistent trends among cultivars, except with `Bartlett' pear, which was frequently negatively affected. ABA appears to be very promising as a nursery tree defoliant.
Phenology, Breeding System, and Fruit Development of Cultivated Argan [Argania spinosa (L.) Skeels]
Authors: Nerd Avinoam , Irijimovich Vered , Mizrahi Yosef
Published: February 2019

Argan is a wild tree native to southwestern Morocco, appreciated for its edible, high nutritional oil, extracted from the kernels of the drupe-like fruit. Aspects of its reproductive biology were studied with the aim to domesticate argan as an oil crop. Flowering of fertigated trees cultivated in the Negev Highlands of Israel was confined to the spring months. The flowers were found to be protogynous, the stigma protruding from the flower before anthesis. Stigma receptivity at the pre-anthesis phase was a third of that at anthesis. Results of different pollination treatments showed that a pollen vector was necessary for pollination and that fruit set was significantly higher in cross and open pollination (7% to 9%) than in self pollination (0.5%). Since in-vivo pollen germination and pollen tube growth in the pistil were similar for foreign and self pollen, the lower fruit set obtained in self pollination may have been related to postzygotic discrimination. Pollen transfer by wind was restricted to short distances, and flies (family Calliphoridae), were proven to be involved in pollination. In contrast with stands in argan's native habitat, where fruit growth is inhibited in summer, fruits of the cultivated trees grew continuously throughout the summer. The pattern of growth of fruit fresh weight was similar to that shown for typical fleshy drupaceous fruits, with an initial and a final phase of rapid growth interrupted by a phase of slow growth.
Improved Orchard Establishment of Asimina triloba Seedlings on Acid Soils Supplemented with Calcium Sulfate
Authors: Picchioni G.A. , Graham C.J.
Published: February 2019

Asimina triloba (L.) Dunal (pawpaw), a deciduous tree indigenous to the eastern U.S., is being considered as a potential new fruit crop. The difficulty in establishing transplanted pawpaw seedlings has been identified as an important research need for successful cultivation of this species. We have addressed the possible benefits of soil-applied CaSO4 in establishing pawpaw seedlings on acidic, low-Ca orchard soil. Two-year-old seedling rootstocks were planted at a spacing of 1.5 m (within rows) × 5.5 m (between rows), and trickle-irrigated (with N, P, and K) for two growing seasons. Before planting, CaSO4 was applied at rates of 0, 11, and 22 t/ha and incorporated to a depth of 15 cm. Seedling trunk cross-sectional area (TCA) growth increased with increasing CaSO4 application. After the first season, increases in TCA averaged 27% and 44% greater with CaSO4 treatments (11 and 22 t/ha, respectively), as compared to the 0 t/ha treatment. This effect was accentuated by the end of the second season. Average qualitative ratings (based on seedling vigor and appearance) were also improved with CaSO4 treatment. These findings indicate that establishment of pawpaw seedling rootstocks may be improved with Ca fertilization in orchards of low-Ca status. Additional data, including seedling dry matter accumulation, will be presented.
Greenhouse Screens and Their Efficacy Against Whiteflies and Thrips
Authors: Bell Michelle L. , Baker James R.
Published: February 2019

Twenty-eight greenhouse screening materials, with predetermined airflow resistance values, were evaluated for exclusion of silverleaf whitefly (Bemisia argentifolii Perring & Bellows) and thrips from a mixed-species population. Screens differed in exclusion efficacy, as a percentage of the fiberglass window screen control and at an approach velocity of at 92 m/min, from –35 to 94% for silverleaf whitefly and from –13 to 95% for thrips. Seventeen screens excluded more silverleaf whitefly, whereas seven excluded more thrips than the window screen control. One material differentially excluded whitefly over thrips; many more differentially excluded thrips over whitefly. Airflow resistance, indicative of mesh hole size, did not necessarily correspond with degree of exclusion. Though two high-resistance screens, No-Thrips and Econet S, excluded both pests, not all materials characterized as highly resistant to airflow provided significant exclusion. Exclusion of both pests was also attained with three moderate resistance screens, BugBed 123, BugBed 85, Pak 44×44, and one low-resistance screen, BugBed 110UV.
Effects of Supplemental Light on Growth, Photosynthesis, and Carbohydrates Synthesis in the Leaves of Tomato (Lycopersicon esculentum L.) Grown under Different Greenhouse Covering Materials
Authors: Erhioui Mohamed Badrane , Dorais M. , Gosselin A. , Papadopulos A.P.
Published: February 2019

Most experiments on the effects of cover materials on greenhouse crops have provided no real statistical replication for the cover materials. This study was conducted in Winter 1996 at the Harrow Research Centre (Ontario) in nine minihouses covered with glass (single-glass), D-poly (double inflated polyethylene film), and acrylic (rigid twin acrylic panel) offering a 3 × 3 latin square experimental design. Tomato plants (Lycopersicon esculentum L.) were grown in CO2-enriched atmosphere (1000 ppm) under three covering materials, and two light treatments (natural light, and supplemental light at 65 μmol·m–2·s–1) in order to determine the effects of supplemental light on growth, photosynthesis, reproductive carbon allocation, and evolution of carbohydrates synthesis in the diurnal cycles. Overall, the application of supplemental light increased photosynthesis rate, yields, harvest index, total chlorophyll content, and starch accumulation in all treatments, regardless of the type of cover materials. Early marketable yield in acrylic and D-poly houses was higher than in glasshouses. Plants grown under enhanced light intensity flowered earlier and produced 12% more marketable fruits than those grown under natural light. The photosynthetic rate of plants grown in acrylic houses was higher than that of plants grown in glasshouses and those grown in D-poly. The leaves of plants grown in acrylic and D-poly houses had higher dry mass contents and much higher specific leaf weight (>10%) than plants in glasshouses. The net photosynthesis dropped after 3 months of treatment, accompanied by a high accumulation of carbohydrates in the leaves. These results indicate that a photosynthetic acclimation occurs earlier during the growth period suggesting a limitations in carbon metabolism.
Expression of “Rooting” Genes iaaM and rolB Under Regulatory Promoters in Tobacco
Authors: Sargent Wayne A. , Cheng Zong-Ming
Published: February 2019

Hybrid aspen is a major source of fiber in the north-central United States. One major problem for utilizing genetically improved aspen, and a variety of other woody species, is the difficulty in rooting hardwood cuttings. The objective of this project was to construct and confirm the function of genetic transformation vectors with two rooting genes (iaaM from Agrobacterium tumefaciens and rolB from A. rhizogenes) using three promoters (CaMV35S, soybean heat shock-inducible and poplar wound-inducible promoters). The gene constructs can be used to transform aspen for improvement of rooting hardwood cuttings and to elucidate rooting mechanisms. Each of these six gene constructs was inserted contiguously upstream from the promoter-less-glucuronidase (GUS) gene in the plasmid pBI 101. The engineered plasmids were transformed into A. tumefaciens strain LBA 4404 by electroporation. The functions of the genes were confirmed by transforming Nicotiana tabacum with these constructs. In plants transformed with iaaM and rolB under the CaMV35S promoter, the GUS gene expressed constitutively. These plants were also morphologically abnormal, with callus (and sometimes root) formation on stem tissue. The plants transformed with heat shock and Win6 constructs had no root formation and little or no GUS expression, without induction. After induction with heat shock (42°C for 1 hr per day for 7 days) or wounding (wounding the plants daily for 7 days), root formation occurred and GUS expression increased significantly with each gene, respectively. No roots developed in the non-transformed control shoots. The transformed plants with the regulatory promoters appeared morphologically normal. These constructs are currently being tested in hybrid aspen.
Field Evaluation of Azalea Species and Cultivars for Resistance to Azalea Lace Bug and Cranberry Rootworm
Authors: Robacker Carol D. , Braman S.K.
Published: February 2019

Azalea lace bug (Stephanitis pyrioides) is the most serious pest on azalea. Both evergreen and deciduous azaleas are susceptible, though more resistance has been observed in the deciduous. To identify genes for resistance, fourteen deciduous azalea species, three deciduous azalea cultivars derived from complex hybrids, and one evergreen cultivar were planted in a randomized complete-block design under mixed deciduous trees in the fall of 1994. Each block was replicated 12 times. In the spring and summer of 1995, azalea lace bugs were introduced onto branches of six plants of each of the taxa. One month later, and again in the fall of 1996, the percentage of infected shoots per plant was measured. Very little damage from azalea lace bug was observed on the R. canescens, R. periclymenoides, and R. prunifolium plants, while `Buttercup', `My Mary', R. japonicum, and R. oblongifolium had the greatest damage. The cranberry rootworm, Rhadopterus picipes, damages many woody ornamentals, including some azalea species. The injury appears as elongated cuts on the leaves, and is most severe on plants growing under dense canopies. The cranberry rootworm has been observed in this azalea field plot. Plants were evaluated for damage in June 1995 and 1996. Cranberry rootworm damage was most severe on `Buttercup', R. japonicum, R. prinophyllum, and R. calendulaceum, while the evergreen azalea `Delaware Valley White' was the most resistant.
Influence of the rolC Gene on Proteins Associated with Stroma and Thylakoid Membranes of Chloroplasts in Transgenic Plants of Kentucky Bluegrass
Authors: Ke Shanqiang , Lee Chiwon W. , Duysen Murray E.
Published: February 2019

The effects of the expression of the rolC gene on protein accumulation in the chloroplasts of transgenic Kentucky bluegrass (Poa pratensis L.) were investigated. Coleoptile tissues excised from 3-day dark-grown seedlings were bombarded with tungsten particles coated with DNA of the engineered plasmid, pGA-GUSGF, containing the npt II, gus, and rolC genes. The tissues were cultured on callus induction medium, which consists of MS salts supplemented with 0.2 mg/L picloram, 0.01 mg/L naphthaleneacetic acid (NAA) 250 mg/L kanamycin, and 100 mM acetosyringone. The putative transformants were either albinos or variegated plants composed of white and green sections. These albino plants had little or no stroma-based 56-kDa and 14-kDa subunits of the suspected Rubisco proteins, which are expressed in response to genes in the nucleus and plastid, respectively. The albino plants also lacked the 110-kDa and 57–58-kDa, and 43, 47-kDa polypeptides in PS I, coupling factor, and PS II in thylakoid membranes, respectively. These proteins involved in photosynthesis are translated from plastidbased genes. No light-harvesting complex proteins (LHC) were observed in these albino plants. LHC genes are encoded in the nucleus. The thylakoid membrane proteins in the chloroplasts of the rolC transgenic variegated plants contained these proteins. Our data suggest that the nucleus and plastid gene products for plastid development are concomitantly impaired by expression of genes in the transgenic plants.
Water Loss Changes of Antirrhinum majus L. Cut Flowers as Influenced by Genotype
Authors: Stimart Dennis P. , Schroeder Kenneth R.
Published: February 2019

Cut flowers of a short(S) lived (3 days) inbred, a long(L) lived (15 days) inbred and their hybrid (F1, 7.3 days) of Antirrhinum majus L. were evaluated for water loss when held in deionized water under continuous fluorescent light at 25°C. Flowering stems for water loss evaluation were harvested when the basal five to six florets expanded. Cut stems were placed in narrowed-necked bottles with the open area between the stem and bottle sealed with Parafilm. Stem weight and water weight in the bottle were taken every 24 h. Water loss evaluation was continued until 50% of the open florets on the flowering stem wilted or turned brown. Overall, water loss from all accessions was highest 24 h postharvest, declined rapidly between 24 to 96 h, and remained unchanged throughout the remainder of postharvest life. Between 24 to 96 h, the slope of the line for water loss was greatest for L, least for S, and intermediate for the F1. It appears that longest postharvest life of A. majus is associated with the most rapid decline of water loss immediately postharvest to a level, which remains constant.
Response of Arabidopsis hy Mutants Grown in Lower Day/ Higher Night Temperatures (–DIF)
Authors: Bachman Gary R. , McMahon Margaret J.
Published: February 2019

It is theorized that photomorphogenic reductions in stem elongation are similar to thermomorphogenic plant response, i.e. increased red:far-red light response is similar to –DIF (day temperature < night temperature). The long hypocotyl (hy) mutants of Arabidopsis thaliana Landsberg are phytochrome mutants that are less responsive to light quality than wild type. These include mutants of phytochrome chromophore biosynthesis (hy 1, hy2, hy6), phytochrome B (hy3), blue-light receptor (hy4), and signal transduction (hy5). These mutants were grown in growth chambers with temperatures of 18C day/24C night (–DIF) and 24°C day/18°C night with a 14-h photoperiod. Lighting consisted of both incandescent and fluorescent lamps. Growth measurements of five of the mutants were consistent with reported effects of DIF. The height of these plants were significantly greater in the +DIF regime when compared to –DIF. The hy5 mutant showed little difference in the height measurements of plants grown in either -DIF or +DIF. This mutant has a phytochrome signal transduction deficiency. This result indicates that a functional photoreceptor is required, even in reduced quantities as in the phytochrome chromophore biosynthesis mutants, to signal perception of DIF temperature conditions.
Growth of Poinsettia in Potting Media Amended with Ground Kenaf Stem Core
Authors: Lang Harvey J.
Published: February 2019

Euphorbia pulcherrima Willd. `V-14 Glory Red', `V-17 Marble', and `Jingle Bells 3' were grown in various peat-based potting media amended with ground, non-composted woody stem core of kenaf (Hibiscus cannabinus L.) and fertilized at every irrigation with a 17N–2.2P–13.8K fertilizer at 300 ppm N. Kenaf is an annual tropical species grown in several Gulf Coast states as a fiber crop. Growth and overall quality of all cultivars was best in media containing 50% to 70% coarse grind of kenaf (by volume) and was similar to a commercial soilless control medium (Sunshine #1, SunGro Horticulture, Inc.). Media containing greater than 70% fine grind kenaf resulted in significantly smaller plants with chlorosis of both lower and upper leaves, and also resulted in undesirable shrinkage of media in the containers. Addition of 19N–2.6P–10K Osmocote to kenaf-amended media at a rate of 3.5 kg·m–3 resulted in significantly better plants with less chlorosis than similar media without Osmocote. Media containing kenaf also resulted in significantly less water-holding capacity than Sunshine #1 and required morefrequent irrigation to sustain the growth of plants.