bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Canopy Angle and Row Spacing on Tree Growth, Yield, Light Interception, and Fruit Quality of Y-trellis-trained Apple Trees
Authors: Robinson Terence L.
Published: February 2019

`Empire'/M.9/MM.106 and `Ace Delicious'/MM.106 apple trees were planted in 1985 at three between row spacings (3.0 m, 4.25 m and 5.5 m) and were trained as either free standing central leaders or as Y-shaped hedgerows for 13 years. The Y hedgerow arms had varying angles from 40° to 80° above the horizontal. Final scaffold length, canopy volume, trunk cross-sectional area, and above-ground canopy weight were positively correlated to the angle of the Y arms. As the angle of the Y arms became more horizontal, the amount of growth removed during summer pruning increased. At the flattest angle (40° above horizontal), terminal growth of both cultivars ceased and excessive vertical sucker growth resulted. As the angle of the Y arms became more vertical, more terminal growth was obtained and less shoot growth had to be removed during summer pruning. Cumulative yields of the Y-shaped trees were generally greater than those of the central-leader-trained trees. Exceptions were the most horizontal and the most vertical canopy angles, which had the lowest yields. The relationship between angle of Y arms and yield showed a broad optimum between 50° and 70° above the horizontal. There was also a strong positive relationship between tree density and yield. `Empire' fruit size was smaller from the Y-shaped trees than from the central-leader trees. The optimum angles for fruit size were the intermediate angles. Fruit color was poorest on the flattest angles and best on the most-vertical angles. The best yield efficiency was at intermediate angles (50° 70°). This resulted in the best balance of vegetative growth and cropping.
Yield Mapping and GIS for Root Crops
Authors: Panneton Bernard
Published: February 2019

I will show how yield mapping data, aerial photography data, and other agronomic data (fertility, soil parameters) can be integrated into a Geographical Information System (GIS) and give a “feel” of the value of these tools to look at crop production as a whole. The capability of GIS in handling and displaying several layers of georeferenced data leads naturally to a decisionmaking process quite similar to the one used in traditional photo interpretation of aerial imagery. This approach can be very valuable for farm managers and consultants in crop production.
The Use of Websites in Horticultural Classroom Instruction
Authors: Sistrunk Laurence
Published: February 2019

The use of WWW for college curricula has proliferated at an exponential rate over the past 3 years. This sudden deluge of information of all types has provided valuable resources for college instruction. The working website has many advantages for students. By dissecting the components, we can, as instructors, increase our effectiveness and ability to provide our students with useful tools for the near future.
In-furrow Starter Fertilization Enhances Growth and Maturity in Early Sweet Corn
Authors: Swiader John M. , Shoemaker William H.
Published: February 2019

Field studies were conducted in 1994 and 1995 to evaluate the effects of in-furrow-placed (i.e., applied directly in the seed channel) starter fertilizer on the emergence, maturity, and yield response of early sweet corn. In both years, three starter fertilizer treatments were applied: APP, with N and P at 13 and 19 kg·ha-1, respectively (13N—19P kg·ha-1), either banded (5 cm below and 5 cm to the side of the seed) or placed in-furrow, and a control (no starter fertilizer). Additionally, in 1995, the rate of APP was increased to supply 26N—38P kg·ha-1 in combination with either band (5 × 5 cm) or in-furrow placement. Seedling emergence was delayed whenever starter fertilizer was applied with the seed; however, significant reductions (≈21%) in plant stand occurred only at the high rate of in-furrow placement. In both years, all starter treatments had a positive effect on seedling dry-matter production, and hastened silking. In-furrow application of 13N—19P kg·ha-1 increased marketable ear yields 34% in 1995, but had no effect in 1994. Lack of yield response to the high rate of in-furrow fertilizer in 1995 was primarily a function of reduced stand, as ear number and ear mass per plant, and average ear size were similar to those in the other starter treatments. Based on these results, in-furrow APP at 13N—19P kg·ha-1 appears to be an effective starter fertilization regime for early sweet corn, comparable in effect to banded 26N—38P kg·ha-1. However, high rates of in-furrow APP may reduce stands. Although significant yield response to in-furrow starter fertilizer may not always be realized, the increased early seedling growth may itself be a benefit, since fast-growing seedlings are more likely to be tolerant of adverse environmental conditions than are less vigorous plants. Chemical name used: ammonium polyphosphate (APP).
Using Ethephon and GA3 to Overcome Thermoinhibition in `Jalapeño M' Pepper Seed
Authors: Carter Anne K. , Stevens Roseann
Published: February 2019

`Jalapeño M' pepper (Capsicum annuum L.) seeds were soaked for 40 h in solutions of 0.0, 0.5, 1.0, 2.0, or 3.0 mM GA3 (using Release, 10% GA3) and 0.0, 1.75, 3.5, 7.0, or 10.5 mM ethephon in all combinations in petri dishes at 25 °C. The seeds were rinsed, dried for 24 hours, then germinated at either 25 or 40 °C. Thermoinhibition was induced at 40 °C, as nontreated seeds failed to germinate, but 99% of the seeds germinated at 25 °C after 7 days. Pretreatment with H2O alone partially alleviated thermoinhibition at 40 °C (41% germination). Pretreatment with ethephon alone resulted in up to 50% germination and with GA3 alone up to 79% germination. The effects of the GA3 and ethephon were additive, as the highest germination percentage (91%) at 40 °C was obtained with 3.5 mM ethephon + 3.0 mM GA3. The percentage of abnormal radicles was <1% in all treatments. Chemicals used: (2-chloroethyl) phosphonic acid (ethephon); gibberellic acid (GA3).
Independence of the mj Nematode Resistance Gene from 17 Gene Loci in Cucumber
Authors: Walters S. Alan , Wehner Todd C.
Published: February 2019

Root knot caused by Meloidogyne spp. is an important disease of cucumber. Resistance to M. javanica in cucumber (Cucumis sativus L.) is conferred by the newly discovered mj gene. The objective of this research was to determine whether mj was linked to other genes controlling morphological or disease resistance traits in cucumber. Four inbred lines homozygous for mj (LJ 90430, `Manteo', NCG-198, and NCG-199) were crossed with inbreds (`Coolgreen', M 21, NCG-101, WI 2757, and `Wisconsin SMR 18') to form six families: NCG-101 × LJ 90430, WI 2757 × LJ 90430, NCG-199 × `Wis. SMR 18', NCG-198 × M 21, `Manteo' × M 21, and NCG-198 × `Coolgreen'. F2 progeny were evaluated in all families, and BC1 progeny were evaluated only in the NCG-199 × `Wis. SMR 18' family. Meloidogyne javanica resistance and the 17 other traits controlled by simple genes were evaluated in greenhouse or field tests. None of the 17 genes were linked with mj. Therefore, cucumber breeders interested in nematode resistance should be able to incorporate the trait into lines without having to break linkages with the 17 genes used in this study.
Multiple Shoot Production In Vitro of the Tropical Timber Tree, Sentang (Azadirachta excelsa Linn.)
Authors: Liew T.K. , Teo C.K.H.
Published: February 2019

Axillary buds from 5-month-old seedlings of Azadirachta excelsa Linn. were surface-sterilized twice with 1.35% (m/v) and 1.05% (m/v) of sodium hypochlorite for 25 and 15 minutes, respectively, before culturing on Murashige and Skoog (MS) medium containing combinations of BA and NAA. A combination of 4.4 μM BA + 0.5 μM NAA induced the most axillary buds to grow (eight per explant). Subsequent proliferation of the micropropagated shoots on this medium yielded abnormal shoots. The best medium for maximum proliferation of these micropropagated shoots contained 3.3 μM BA and 0.27 μM NAA. On this medium about four normal shoots were produced per explant. These findings indicate that two different media are needed for successful micropropagation of sentang. Chemical names used: N6-benzylaminopurine (BA); 1-naphthaleneacetic acid (NAA).
Incidence of Rio Grande Gummosis of Grapefruit Is Not Associated with Concentrations of Anions in Soil Water
Authors: Li Y.C. , Alva A.K. , Calvert D.V. , Sonoda R.M. , Pelosi R.R. , Banks D.J.
Published: February 2019

The objective of this study was to evaluate the role of chloride (Cl-) and other anions in soil water on the incidence and severity of Rio Grande Gummosis (RGG) in grapefruit (Citrus paradisi MacFadyen) trees. White `Marsh' grapefruit trees on sour orange (C. aurantium Lush.) rootstock were grown on two-row raised beds. Due to differential rates of K application (as KCl), the trees received various rates of Cl- ranging from 0 to 156 kg·ha-1 per year. Soil water was sampled using suction lysimeters at 120- and 180-cm depths. The severity of RGG was evaluated 18 months following the application of various rates of KCl. The concentration of Cl- in soil water samples varied from 16.2 to 617 mg·L-1, with mean concentrations across all treatments of 160.7 and 188.4 mg·L-1 for 120- and 180-cm depth water samples, respectively. The concentrations of Cl- and other anions (
, , ) in soil water at either 120- or 180-cm depth were poorly related to the incidence or severity of RGG (R = -0.10 to -0.28). Chloride concentrations in the soil water ranged from 20 to 617 mg·L-1 near the RGG-free trees, and from 16.7 to 310 mg·L-1 near the trees that were affected by RGG. This suggests that under the conditions of this study, neither the incidence nor the severity of RGG was influenced by high concentrations of Cl- in the soil water.
Bagging `Fuji' Apples during Fruit Development Affects Color Development and Storage Quality
Authors: Fan Xuetong , Mattheis James P.
Published: February 2019

Enclosing `Fuji' apple (Malus ×domestica Borkh.) fruit in paper bags 2 months after full bloom delayed the increase in internal ethylene concentration at the onset of fruit ripening, and increased the respiration rate early in the bagging period. Bagging delayed and reduced red color development, especially on the blush side, but did not affect fruit resistance to gas diffusion. External surface color changed significantly within the first 4 days after bags were removed. Exclusion of UV-B from sunlight by Mylar film after paper bag removal impaired red color development. Bagging during fruit development increased superficial scald but eliminated stain during cold storage. Exposure to sunlight for 19 or 20 days before harvest reduced scald incidence in comparison with leaving bags on until harvest.
Evaluation of Two Growing Systems for Cut Snapdragon Production: Tray vs. Ground Bed
Authors: Sullivan K. Jacquemin , Pasian C.C.
Published: February 2019

Cut-flower production of three snapdragon (Antirrhinum majus L.) cultivars (`Potomac Pink', `Winter White', and `Potomac Light Pink') in growing trays vs. ground beds was evaluated in five different plantings over a period of a year and a half. The experiments evaluated the quality of cut flowers from plants in ground beds or in small vs. large trays either raised or placed directly on the ground bed. The quality of flowering shoots was lower when plants were grown in raised trays rather than in on-ground trays or in ground beds, but other treatments did not affect quality consistently. Flowering shoot grade (a subjective quality indicator) correlated well (r = 0.8) with the ratio of shoot dryweight to shoot length (an objective quality indicator). Our results confirm that the flower quality of snapdragons grown on ground trays can equal that of those grown in ground beds.
Fruit Characteristics of `York' Apples during Development and after Storage
Authors: Ingle Morris , D'Souza Mervyn C. , Townsend E.C.
Published: February 2019

Firmness, soluble solids concentration (SSC), starch index (SI), internal ethylene concentration (IE), and titratable acid concentration (TA) of `York Imperial' apple (Malus ×domestica Borkh.) fruit changed linearly with harvest date between 152 and 173 days after full bloom (DAFB). Firmness was positively correlated with TA, SSC was correlated with SI, and SI was negatively correlated with TA. After 150 days of refrigerated-air (RA) storage, there was no relationship between DAFB at harvest and firmness or superficial scald, but the malic acid concentration declined linearly and storage decay increased linearly with DAFB. Firmness had declined to a plateau and was not correlated with any variable at harvest. Malic acid concentration after CA storage was correlated with DAFB, firmness, SSC, and SI; scald was correlated with firmness and SI; and decay was correlated with DAFB, firmness, SSC, and SI. During 150 days of controlled-atmosphere (CA) storage (2.5% O2, 1.0% CO2), firmness and TA decreased as a linear function of DAFB. Percentage of fruit with scald and scald rating changed quadratically with DAFB, and decay increased linearly with DAFB. After 150 days of CA, firmness was correlated with DAFB, SI, and IE at harvest; TA was correlated with DAFB, firmness, SSC, TA, and SI; scald was correlated with firmness and SI; and decay was correlated with DAFB, SSC, and scald index at harvest. During 250 days of CA storage, firmness, TA, scald, and decay changed linearly with DAFB in only 1 or 2 years out of 3. Formulas were created to predict firmness after CA within 10 to 12 N (2.0–2.5 lb-f) and TA to within 25%.
Black Polyethylene Mulch Does Not Reduce Yield of Cucumbers Double-cropped with Tomatoes under Heat Stress
Authors: Hanna H.Y.
Published: February 2019

Black polyethylene mulch is preferred for producing early spring tomatoes (Lycopersicon esculentum Mill.) because of its warming effect on the soil around the roots. However, using the same mulch for double-cropping cucumbers (Cucumis sativus L.) with tomatoes is considered by some growers to be undesirable because of the belief that heat accumulation under the mulch in midsummer or early fall is detrimental to cucumber yield. Eight studies were conducted from July to September in 1994, 1995, and 1996 to determine the effects of mulching spring tomatoes with black vs. white polyethylene mulch on the growth and yield of subsequent cucumber crops. Soil temperature recorded after planting cucumbers ≈4:00 pm for 3 weeks was higher under black mulch than under white mulch. Color of the mulch did not affect leaf length, leaf width, and plant dry weight of cucumbers in six of the eight studies. Cucumbers grown on black mulch produced longer leaves in one study and wider leaves in two studies, and plant dry weight was lower in two studies. Mulch color had no significant effect on the premium or total yields of cucumbers in all but one study. Cucumbers grown on black mulch produced lower percentages of culls in two studies.
Mulch Improves Pecan Tree Growth during Orchard Establishment
Authors: Smith Michael W. , Carroll Becky L. , Cheary Becky S.
Published: February 2019

`Giles' pecan [Carya illinoinensis (Wangenh.) K. Koch] seedlings were either not mulched or mulched with wood chips arranged in a 1- or 2-m-wide square that was 30 cm deep. Mulch treatments were in factorial combination with two N rates applied as either a single application at budbreak or as a split application at budbreak and 3 weeks later. Tree height was positively related to mulch width each year of the 3-year study, and trunk diameter was positively related to mulch width during the second and third years of the experiment. Leaf P and K concentration during 2 years and leaf N during 1 year of the study were positively related to mulch width. Trees receiving the higher N rate were taller during 2 of 3 years, but leaf N concentration was not affected by N rate. No differences in the parameters measured were observed whether N was applied as a single or as a split application.
Cowpea Cover Crop Mulch for Weed Control in Desert Pepper Production
Authors: Hutchinson Chad M. , McGiffen Milton E.
Published: February 2019

A 2-year field project was conducted in Thermal, Calif., to investigate cowpea [Vigna unguiculata (L.) Walp.] mulch as an alternative weed control option in pepper (Capsicum annuum L.) production. Treatments included: bare ground (BG) with hand weeding, BG with no weeding, cowpea mulch (CM) with hand weeding, and CM with no weeding. Cowpea was seeded in July on 76-cm beds and irrigated with buried drip line. Two weeks prior to transplanting peppers, irrigation water was turned off to desiccate the cowpea plants. In September, cowpea was cut at the soil line, mulch was returned to the top of the bed, and pepper plants were transplanted into the mulch and fertilized through the drip line. Every 2 weeks, the number of weeds emerged and pepper plant height were recorded. Fruit production, pepper plant dry weight, and weed dry weight were recorded at harvest in December. Fewer weeds emerged in CM than in BG. The final weed population in nonweeded CM was reduced 80% and 90% in comparison with nonweeded BG in 1997 and 1998, respectively. Weed dry weights in nonweeded CM were 67% and 90% less than those in nonweeded BG over the same period. In 1997 and 1998, respectively, pepper plants produced 202% and 156% more dry weight, as well as greater fruit weight, in CM than in BG. There were no differences in mean fruit weight. Cowpea mulch provided season-long weed control without herbicides while promoting plant growth and fruit production.
Physiological Response of Bermudagrass Grown in Soil Amendments during Drought Stress
Authors: Miller Grady L.
Published: February 2019

The effects of several soil amendments, following a single filling of core aerification holes, on growth and transpiration of `Tifdwarf' bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy] were examined during drought stress. Soil amendments had variable effects on turf quality. In general, turf grown in ZeoPro®- and Profile®-amended sand had the highest quality. Data indicated that the evaluated soil amendments have the potential to influence soil water content, ultimately influencing transpirational response to drought stress. Amended sand contained 1% to 16% more transpirable water compared with non-amended sand. Turfgrass grown in Axis®- and Isolite®-amended sand required 0.4 to 1.4 days longer to reach the endpoint (transpiration rate of drought stressed plants <12% of well-watered plants) during a period of rapid water depletion. Data from this study suggest that the total volume these amendments occupied in the root zone, following a single filling of core aerification holes in sand, may positively influence soil moisture status, resulting in an increase in drought avoidance.
Description of Lignified Vascular Nodules in Fruit of `Gala' and Other Apple Cultivars
Authors: Lane W.D. , McKenzie D.-L. , Meheriuk M.
Published: February 2019

Nodules associated with the main cortical vascular bundles in fruit of the `Gala' apple (Malus ×domestica Borkh.) strains `Royal' and `Regal' were observed in several growing seasons. The nodules were found in 68% (n = 586) of the fruits examined, with a mean of 2.5 nodules per fruit. The nodules were first detected in developing fruit 2 months after bloom and were normally 1-2 mm in diameter by commercial harvest maturity. The nodules, like the vascular bundles, were pale green. They were inconspicuous at first, but became conspicuous and unattractive and changed to brown or red as the fruit became overmature. Nodules in the fruit of the `Gala' × `Splendour' hybrid `8S 27-2' were dark brown or red at picking maturity, and occurred with high frequency. Nodules were also observed in `Splendour', but were small, pale green, and infrequent in this cultivar. Microscopic examination of the nodules revealed that they typically contained a central cavity surrounded by a lignified wall with small pigmented cells outside the wall adjacent to the cortex. Low-frequency irrigation cycle times generally promoted the development of nodules in both `Gala' strains but nitrogen treatments did not affect nodule frequency in `Royal Gala'. Mean fruit nodule frequency tended to be higher, overall, in `Regal Gala' (3.9) than in `Royal Gala' (1.4).
Responses of Native Australian Cut Flowers to Treatment with 1-Methylcyclopropene and Ethylene
Authors: Macnish Andrew J. , Simons David H. , Joyce Daryl C. , Faragher John D. , Hofman Peter J.
Published: February 2019

Postharvest longevity of some cut flowers is shortened by exposure to ethylene gas. Adverse effects of ethylene may be prevented by treatment with 1-methylcyclopropene (1-MCP) gas. Responses of 14 different native Australian cut flowers to 1-MCP and ethylene applied at concentrations of 10 nL·L-1 and 10 μL·L-1, respectively, were examined. Each gas was applied alone for 12 hours at 20 °C and they were also applied in series. Vase lives of Ceratopetalum gummiferum, Chamelaucium uncinatum, Grevillea `Kay Williams' and `Misty Pink', Leptospermum petersonii, Telopea `Shady Lady', and Verticordia nitens were reduced by ethylene treatment. Treatment with 1-MCP generally protected these cut flowers against subsequent exposure to ethylene. The 1-MCP treatment usually did not extend their vase lives in the absence of exogenous ethylene.
Flower Bud Removal and Cytokinin Treatment Stimulate Capitulum Formation in Double-flowered Zinnias
Authors: Miyajima Daiichiro
Published: February 2019

The increase in the capitula of zinnia plants (Zinnia violacea Cav.) was investigated by analyzing the production of shoots. The effects of removing the buds for capitula and application of BA on the production of shoots were also evaluated. It took ≈40 to 50 days from the emergence of axillary buds to the opening of the capitula at the apices of the shoots from these axillary buds. The application of BA shortened the number of days for the same process. The difference in the number of days from emergence of the axillary buds to that of the first descendant axillary buds was ≈25. The total number of capitula opened was greater in plants with the bud removal treatment than in intact plants. Chemical name used: (N-phenylmethyl)-1H-purine-6-amine (BA).
016 Assessment of Insecticide Efficacy for Root Weevil Control
Authors: Rosetta Robin , Svenson Sven E. , Bell Neil
Published: February 2019

In July 1999, adult stages of root weevils were established in 1-gal containers planted with Rhododendron `PJM.' Each pot was inoculated with one black vine weevil, three rough strawberry root weevils, and four strawberry root weevils. On 12 July, insecticide spray treatments were applied. Treatments were evaluated for percent adult mortality at 7 and 14 days after treatment (DAT). Black vine weevils were more sensitive to the insecticides studied than either strawberry root weevil or rough strawberry root weevil. There was considerable mortality of the black vine weevils and rough strawberry root weevils in the untreated plots by 14 DAT. Talstar Flowable (bifenthrin), Alta (deltamethrin), Topside (lamda cyhalothrin), and CGA 293 343 (thiamethoxam) all gave 100% control 7 DAT. Additionally, Closure (bendiocarb) and acephate gave 75% or better control at 7 DAT. Rough strawberry root weevil had 100% mortality in only the Alta-treated plots at 7 DAT, followed by 93% and 80% mortality in Topside and acephate-treated plots, respectively. Mortality of the strawberry root weevils in the untreated plots by 14 DAT remained relatively low. Strawberry root weevils were more resistant to the applied insecticide treatments. Only Topside-treated plots had 90% or greater mortality at 7 DAT, followed by Talstar (60%), Alta (58%), and acephate (54%). Topside-treated plots had 90% or greater mortality at 14 DAT followed by Talstar (76%), Alta (68%), and Closure (60%). Combined root weevil species mortality showed highest mortality at 7 DAT in Topside-treated plots (87% or greater), followed by Alta (74% or greater), and acephate (73%).
028 Amaranthus dubius Interference in Sweetpotato
Authors: de L. Lugo Maria , Ortiz Carlos E. , Rosa-Marquez Evelyn
Published: February 2019

Amaranthus dubius is a common weed in sweetpotato production throughout the Caribbean Basin. A field study was conducted in the Agricultural Experiment Station at Juana Diaz, P.R., during 1998 to determine the effect of A. dubius interference in sweetpotato production under tropical conditions. Interference was evaluated by using a randomized complete-block design with four replications. Plots were four 6.1-m rows divided into two sections for yield and growth determinations. Intraspecific and interspecific interference was measured for both species. A. dubius was grown at 15 and 30 plants per meter of row. Plant dry weight and leaf area were determined at 3, 6, 9, 12, 15, and 18 weeks after planting (WAP). Sweetpotato yield was determined at 29 WAP. A. dubius growing alone reached a maximum leaf area index (LAI) of 8.5 at 12 WAP. Sweetpotato, however, did not attain maximum LAI. When grown with A. dubius, sweetpotato biomass was reduced at 15 WAP. This reduction was 62% and 66% for 15 and 30 A. dubius plants per meter of row, respectively. Sweetpotato yield in weed-free plots was equivalent to 9232 kg/ha. Yield reduction was 96% for 15 A. dubius per meter of row and 100% for 30 plants.
040 Identification of Itea virginica Cultivars using DNA-based Techniques
Authors: Lindstrom Jon T. , Pelto Matthew C.
Published: February 2019

Itea virginica (Virginia Sweetspire) is a woody landscape shrub that has recently gained much popularity in the landscape. Several cultivars of Itea have been selected for fall leaf color and plant habit. Visual identification of some of these cultivars is difficult and confusion exists in the trade. RAPDs (randomly amplified polymorphic DNA) were used to identify Itea virginica cultivars. A single 10-base primer was sufficient to separate the cultivar Saturnalia from the cultivar Henry's Garnet. Two dwarf cultivars of I. virginica, `Merlot' and `Sprinch' (= Little Henry), were separable from `Henry's Garnet' using a single 10-base primer. A primer that distinguishes between these two dwarf cultivars has not yet been found. The technique of RAPDs appears sufficiently sensitive and repeatable to resolve questions of identity that may exist among several cultivars of Itea.
054 A New Fresh Market Spinach
Authors: Morelock T.E. , Kirkpatrick J.A. , Motes D.R. , Correll J.C. , Daniello F.J.
Published: February 2019

The current national trends in nutrition have resulted in a very high interest in the benefits of proper diet. It is very apparent that adding foods high in antioxidants to the human diet can have drastic affects on human health by reducing the risk of cancer, cardiovascular and pulmonary disease, as well as age-related degenerative diseases. It is well-known and well-documented that spinach is one of the very best vegetables in antioxidant potential. It is high in beta-carotene (provitamin A) and is also very high in lutein (a carotenoid that is a strong antioxidant but with no vitamin A activity). Lutein has also been documented to have the potential to significantly reduce macular degeneration in humans when added to the diet on a regular basis. With these health benefits in mind the Univ. of Arkansas is releasing the spinach breeding line that has been tested as 88-310. It is a slow-growing semi-savoy that exhibits excellent color and has a moderate level of white rust resistance. It has excellent plant type, producing a very attractive compact rosette plant that is very desirable for root cut whole plants or for various types of clipped spinach. It is best-suited to both fall and overwinter production in Arkansas and for winter production in the Texas wintergarden. Seed for tests can be obtained by contacting T.E. Morelock, Dept. of Horticulture, Univ. of Arkansas, Fayetteville, AR 72701.
060 Differential Responses of Egyptian Faba Bean Genotypes to in Vitro Callus Induction
Authors: Nekouei F. , Kuti J.O.
Published: February 2019

Callus induction in 12 genotypes of faba bean (Vicia faba L.) genotypes from Egypt were examined. Cotyledon, leaf petiole, and stem explants were cultured on two basal agar media; Murashige and Skoog (MS) and Gamborg (B5). The media contained 0.5 mm 2,4-D, 0.25 mm NAA, and 30 g of sucrose/L. Calli were easily formed in B5 media and induction rate was significantly dependent on the genotype. The highest induction rates occurred mostly in genotypes from Assiut Univ., Egypt, and in a local variety `Goya'. These callus cultures will be used for in vitro screening of the faba bean genotypes for tolerance to salt and drought, respectively.
062 Development of Southernpea [Vigna unguiculata (L.) Walp.] Cultivars with an Enhanced Persistent Green Seed Phenotype
Authors: Fery R.L. , Thies J.A.
Published: February 2019

The development of southernpea cultivars with a persistent green seed color has been the subject of much interest in the U.S. horticultural industry for more than two decades because seeds of such cultivars can be harvested at the dry seed stage of maturity without loss of their fresh green color. Two genes, gt (green testa) and gc (green cotyledon), are known that condition a persistent green seed color in southernpea. The gt gene was identified more than 25 years ago, but cultivars containing this gene have not been well-accepted by the industry because of the frequent occurrence of discolored (brown stains) seeds. Cultivars containing the more recently discovered gc gene, however, do not produce the discolored seeds and are used extensively in the frozen food industry. Efforts to develop cream-, blackeye-, and pinkeye-types of cultivars containing both the gt and gc genes are nearing completion. The dry seeds harvested from candidate cultivars homozygous for both the gt and gc genes are stain free and exhibit a deeper and more uniform green color than seeds harvested from cultivars homozygous for just one of the genes. It is anticipated that newer cultivars containing both of the genes that condition a persistent green seed color will not only have an enhanced value to the frozen food industry, but will also have great potential for use in the dry pack industry.
084 Response of Transgenic `Royal Gala' Apple (Malus ×domestica Borkh.) Shoots, Containing the Modified Cecropin MB39 Gene, to Erwinia amylovora
Authors: Liu Q. , Salih S. , Ingersoll J. , Meng R. , Owens L. , Hammerschlag F.
Published: February 2019

Transgenic `Royal Gala' apple (Malus × domestica Borkh.) shoots were obtained by Agrobacterium-mediated gene transfer using the plasmid binary vector pGV-osm-AC with a T-DNA encoding a chimeric gene consisting of a secretory sequence from barley-amylase joined to the modified cecropin MB39 coding sequence. Shoots were placed under the control of a wound-inducible, osmotin promoter from tobacco. The integration of the cecropin MB39 gene into apple was confirmed by Southern blot analysis. The transformation efficiency was 1.5% when internodes from etiolated shoots were used as explants and 2% when leaf explants were used. Both non- and transgenic tetraploid plants were produced by treatment of leaf explants with colchicine at 25 mg·L-1, and polyploidy was confirmed by flow cytometry. Of the diploid transgenics, three of seven were significantly more resistant to Erwinia amylovora than the non-transgenic `Royal Gala' control. Also, in one instance, a tetraploid transgenic was significantly more resistant than the diploid shoot from which it was derived.
088 Differential Expression of Expansin Genes Isolated from Sweet Cherry (Prunus avium L.) during Fruit Ripening
Authors: Wu Zhencai , Wiersma Paul A.
Published: February 2019

Expansins are a class of proteins that stimulate the extension of plant cell walls. Expansins have been found in nearly all growing plant tissues, such as hycopotyls, young seedlings, fibers, internodes, flower petals, and ripening fruits. We isolated two full-length expansin cDNA clones, Pruav-Exp1 and Pruav-Exp2, from sweet cherry (Prunus avium L.) fruit. Pruav-Exp1 has 1048 nucleotides encoding 254 amino acids, while Pruav-Exp2 has 1339 nucleotides encoding 250 amino acids. Deduced amino acid sequences of sweet cherry Pruav-Exp1 and Pruav-Exp2 share 72% identity. A Blast search of the GenBank database with the deduced amino acid sequences of Pruav-Exp1 and Pruav-Exp2 indicated a high sequence identity with other plant expansin genes. Interestingly, Pruav-Exp1 shares 99% identity of amino acid sequence with that of apricot expansin Pav-Exp1. Fragments from the 3' ends of Pruav-Exp1 and Pruav-Exp2 were cloned to generate gene-specific probes. These probes were used to study expansin gene expression in different tissues and during fruit development. Northern blot analysis showed different mRNA expression patterns for each gene. The mRNA of Pruav-Exp1 was expressed at the pink and ripe stages, but not at the early green and yellow stages of fruit development. The mRNA of Pruav-Exp2 was present earlier, from a low level in yellow expanding fruit, increasing to a high level at the pink stage and remaining at this level through the ripe stage. Both mRNAs were also expressed at a low level in flower, but not present in other tissues such as roots, leaves and peduncles. Our study indicates an expansin gene family is present in sweet cherry and suggests that two expansin genes may have different roles during fruit development and ripening.
104 A Dip in Chlorine Water Supplemented with Calcium Propionate Extends the Shelf life of Fresh-cut Honeydew
Authors: Bai Jin-He , Saftner Robert A. , Lee Yuen S.
Published: February 2019

The development of tissue translucency of fresh-cut honeydew cubes adversely affects product quality and primarily occurs in cubes that have been sanitized by dipping in chlorine water (sodium hypochlorite solution) following processing. Chlorine water dips containing calcium propionate as an antimicrobial salt were tested to decrease tissue translucency and extend the marketable shelf life of honeydew (2-cm cubes) sealed in a rigid container with a film overlap and stored at 10 °C for 7 days. Honeydew cubes not dipped following processing had higher respiration rates and microbial populations than cubes that had been dipped, and lost their marketability on day 5 due to off-odor development. Dipping in chlorine water decreased the initial population and growth of microorganisms on the cubes, compared to dipping in water or not dipping. However, translucency developed in cubes dipped in water, with or without chlorine, and became unsalable by day 5. Chlorine water dips containing calcium propionate were devised that maintained excellent antimicrobial characteristics and prevented translucency in honeydew cubes kept 7 days at 10 °C. Quality analyses revealed that calcium propionate treatments decreased respiration and ethylene production rates, maintained tissue firmness, the lightness and brightness of cube surfaces, melon aroma and overall visual quality through 7 days of storage. The calcium propionate dips did not impart or induce any detectable off-flavors or off-odors to the cubes.
114 Multiple Applications Extend Duration of 1-Methylcyclopropene-induced Responses of Apple and Pear Fruit
Authors: Mattheis J. , Argenta L. , Fan X.
Published: February 2019

The ethylene action inhibitor 1-methylcyclopropene (MCP) reduces the rate of ripening of many apple and pear cultivars. The longevity of MCP responses induced by a single application at harvest is dependent in part on MCP treatment concentration and post-application storage conditions. Experiments were conducted using several apple and pear cultivars to evaluate the efficacy of repeated application to prolong the duration of MCP responses. Fruit were treated with MCP at harvest then stored in air at 0 °C. After various storage durations, MCP was reapplied at the same or higher concentrations. Control fruit not exposed to MCP were stored at the same temperature in either air or a controlled atmosphere (CA). Reapplication prolonged MCP responses compared to fruit treated only at harvest and fruit quality after storage was similar to that of fruit stored in CA. Reapplication was most effective when fruit ethylene production was below 0.1 μL·L–1 at the time of reapplication. The use of low concentration MCP treatments at harvest may allow for more predictable ripening of fruit after storage, particularly for pear fruit where softening is desired.
128 Synergistic Effect of AVG, 1-MCP, and CA on Softening of Apples
Authors: Rupasinghe H.P. Vasantha , Murr Dennis P. , DeEll Jennifer R. , Porteous Murray D.
Published: February 2019

Flesh softening is a major quality parameter that can limit long-term storage of apple cultivars. This study investigated the combined effects of preharvest AVG (Retain™) application, 1-methylcyclopropene (1-MCP; EthylBloc™) exposure at harvest, and commercial controlled atmosphere (CA) storage (2.0% O2 + 2.5% CO2) on flesh softening of `Empire' apple. Treatments were assigned in a split-split-plot experimental design; AVG and no AVG application as the main-plot, CA and air storage as the sub-plots, and 0, 0.1 0.5, 1.0 mL·L–1 1-MCP as the sub-sub-plots. Apples were removed from storage at 70 and 140 days after harvest and kept up to an additional 2 weeks at 20 °C for post-storage assessment of ripening. Preharvest AVG application of `Empire' fruit delayed maturation slightly as determined by starch index at harvest, but did not affect fruit size at harvest nor flesh softening in storage. All levels of 1-MCP were equally effective in controlling fruit softening both in air and CA, as 1-MCP-treated fruit were ≈2.5 kg firmer than untreated fruit. This firmness advantage was still evident even after 2 weeks at 20 °C, with CA-stored fruit holding their firmness the best. When all three technologies were combined, treated fruit were overall 156% firmer than control fruit (no AVG, no 1-MCP, air-stored). As well, ethylene production and emanation of aroma volatiles were reduced significantly in these fruit. Therefore, the synergism of AVG, 1-MCP and long-term CA storage could potentially hold flesh firmness and other ripening parameters of apples to values near those found at harvest.
138 Nodulation Capacity of Rhizobia Isolated from Root Zones of Maackia amurensis in Two Chinese Forests
Authors: Kroggel Mark , Schrader James A. , Graves William R.
Published: February 2019

Maackia amurensis Rupr. & Maxim. is a leguminous tree species possessing meritorious ornamental characteristics and is confirmed to associate with rhizobia that fix nitrogen, but few attempts to isolate symbiotically superior rhizobia have been made. Our goals were to isolate rhizobia from the root zones of indigenous trees of M. amurensis in two ecologically distinct forests in the Heilongjiang Province of China, characterize the rhizobia, and compare their effectiveness at causing nodulation of this host plant. Rhizobia were isolated and cultured from nodules that formed on seedlings grown in soils collected in May 1998, from the Maoershan (45°N, 127°E) and Liangshui (47°N, 128°E) Research Forests. Inoculants from each of the 160 isolates were applied to seedlings. A subset of 48 isolates that evoked the most nodules was partitioned by cluster analysis into 12 similarity groups based on measures of number of nodules (17.9 ± 6.5), the ratio of growth rate on two distinct media (2.26 ± 1.8), pH reaction as measured by absorption at 614 nm of bromthymol blue (0.98 ± 0.36), and tolerance to sodium chloride at 15 g/L (23 out of 48). By using single-isolate cultures of similar cellular concentration as inoculants, one isolate from each group and USDA 4349, an isolate obtained during previous research, are being compared for their capacity to infect and nodulate seedlings.
150 Color Fading of Rose Petals Due to a Transient High Temperature Stress
Authors: Oren-Shamir M. , Gal Dela
Published: February 2019

Changes in temperature during rose flower development, often cause a significant fading of flower color, decreasing its market value. We are studying the effect of transient high temperature stress on red roses (Rosa ×hybrida, `Jaguar'). We have found that a transient temperature stress of 39/18 °C day/night respectively for 3 days, in comparison to the growth temperature of 26/18 °C, caused a significant fading to flower color at a mature bud stage. The plant organ responsible for color fading is the flower bud only. When the stress was applied to the whole plant, not including the flower buds, there was no change on the mature bud color. We have also shown that there are specific flower developmental stages sensitive to the transient increase in temperature. Flower buds at the critical stage of development, that have been exposed to temperature increase have a faded pink-red color when matured. Total anthocyanin levels of faded flowers, due to temperature stress, decreased to ≈50%. In addition, the ratio between the two anthocyanidins composing the red color, cyanidin and pelargonidin, changed dramatically due to the temperature stress: flowers on plants that have not overcome a temperature stress had a ration of 1:1, while those that have faded due to the temperature stress have a ration of 2:1 of pelargonidin to cyanidin, respectively. These findings hint to specific stages of anthocyanin synthesis, that are hypersensitive to increased temperature. We are now in the process of identifying and characterizing these stages.
163 The Influence of Apogee and Its Combination with Ethephon, Chemical Thinners, Cations, and/or Adjuvants for Apple Tree Growth Control and Return Bloom
Authors: Byers R.E. , Carbaugh D.H. , Combs L.D.
Published: February 2019

Prohexadione calcium applied as a series of three applications starting soon after petal fall to `Fuji'/M.9 apple trees reduced the number of pruning cuts, pruning time, pruning weight per tree, current season's shoot length, individual shoot weights, and increased number of nodes on the lower 40 cm of shoots. Fruit diameter, soluble solids, starch, or individual fruit weights were not affected by Apogee sprays. Fruit color and firmness were slightly increased in only one experiment. Growth suppression appeared to be greater on trees cropping more heavily. When trees were more heavily thinned, less shoot growth control was achieved. Apogee applied at 250 mg/L in three applications caused a significant increase in fruit set when compared to the control. Alone Vydate, Carbaryl+Oil, or Carbary+Accel+Oil caused fruit thinning, but neither ethephon nor shading 3 days caused significant thinning. Apogee did not influence results of chemical thinners when applied between the first and second Apogee applications. The 10% and the 27.5% Apogee formulations gave similar shoot growth inhibition when applied with Regulaid or Oil+Silwet L-77. When using hard water (well water), the 27.5% Apogee formulation was not as effective as the 10% formulation. The 10% Apogee formulation has more NH4SO4 than the 27.5% formulation w/w; NH4SO4 is used to prevent inactivation of Apogee by calcium and other cations when hard water is used for spraying. The addition of CaCl (frequently used to reduce bitter pit and corkspot disorders) to the 27.5% Apogee formulation caused poorer growth control than with hard water alone. When Apogee was used at 125 mg/L, the addition of NH4SO4 restored the effectiveness of the hard water+CaCl mixture. Alone the additives NH4SO4, Ca Cl, Regulaid, and/or Oil plus L-77, had no effect on tree growth. Apogee plus L-77+Oil provided additional growth suppression when compared to Apogee+Regulaid. In 1998, three applications of Apogee (63 mg/L) or ethephon (135 mg/L) did not affected shoot growth of `Fuji'/M.9 trees at these low rates. Combinations of Apogee and ethephon gave good control of tree growth. Flowering and fruit set were not promoted by any of these applications.
187 Foliar Application of Urea to Citrus: Effects of Non-ionic and Organosilicone Adjuvants
Authors: Orbovic Vladimir , Jifon John L. , Syvertsen James P.
Published: February 2019

Urea solutions, with or without non-ionic (X-77) and organosilicone (L-77) surfactant, were applied to Citrus leaves and isolated cuticles to examine adjuvant effects on urea uptake and leaf net gas exchange. When compared to X-77, L-77 exhibited superior features as a surfactant, resulting in smaller contact angles of droplets deposited on teflon slide. Both L-77 and X-77 had a strong effect on penetration rate of urea within first 20 min of experiment. Effect of L-77 on urea penetration rate decreased quickly within next 20 min, whereas the effect of X-77 was sustained over a 24-h period following application. When compared to solution of urea alone, addition of X-77 to urea resulted in significant increase of the total amount of urea that penetrated the cuticles. The effect of L-77 was smaller, although the total amount of urea that penetrated the cuticles within a 4-day period was similar for both surfactants. Solutions of either urea alone, urea+L-77 and urea+X-77, or L-77 alone, induced a negative effect on net CO2 assimilation (ACO2) for 4 to 24 h after they were sprayed onto leaves. X-77, when applied alone, had no effect on ACO2. Scanning electron microscopy revealed that 1 h after application, leaf surfaces treated with X-77 appeared to be heavily coated, as opposed to those treated with L-77, which appeared similar to untreated control leaves.
196 Growth of Grapevines With and Without Grow Tubes
Authors: Bordelon Bruce P. , Blume Jill
Published: February 2019

Grapevines (cv. Steuben) were field-grown for 1 year to determine the effects of pruning and grow tube use on vine growth. Plots were grown on Crosby-Miami silt loam soils, trickle irrigated as needed to ensure adequate moisture, and provided a 3-ft band of weed control on each side of the row. Vines were trained onto a 5-ft. tall-trellis using the following techniques: 1) pruned to a single shoot and placed in a grow tube supported by a bamboo stake, 2) pruned to a single shoot and trained on a bamboo stake without a grow tube, or 3) left unpruned and trained on four strings radiating out from the vine to the top wire. At the end of the growing season, the vines were destructively sampled for leaf area, total shoot growth, average internode length, shoot diameter, top growth dry weight, and root system dry weight. The results indicate that pruning vines to a single shoot significantly reduced overall vine growth, whether a tube was used or not. Vines trained to single shoots and grown with or without grow tubes did not differ significantly for the various parameters measured. Unpruned vines produced nearly three times more leaf area, more than two times more total shoot length, and more than two times more top dry weight and root dry weight than the other treatments. A sub-set of these vines will be grown for one more season to determine if the negative effects of pruning and/or tubes will effect vine size after a second season.