bluuebunny/crossref_metadata_2025 huggingface dataset:
Elm Growth and Japanese Beetle Damage on Selected Cultivars
Authors: Witte W.T. , Sauve R.J. , Flanagan P.C.
Published: February 2019

Ten single plant replications of 11 taxa were planted 6 May 1994, fertilized regularly, and maintained under drip irrigation. Japanese beetle damage became apparent in mid-June. Sevin SL at 1 qt/100 gal was applied with a tractor-mounted mist blower on 22 June, and 7 and 19 July. Data on Japanese beetle populations were recorded using an arbitrary scale of 0 (no beetles) to 10 (heavy infestation). Damage on each tree was recorded using an arbitrary scale of 0 (no damage) to 10 (completely skeletonized). The annual increment in height and caliper growth was recorded for each tree in Fall 1994. Ulmus japonica and U. glabra `Pendula' had the most height growth (>60 cm increment) but were not significantly different from most other accessions, while NA 60070, U. crassifolia, and NA 60071 had significantly slower growth than the former group(<25 cm increment). Japanese beetles fed first on U. carpinifolia `Variegata', NA 60071, and 60070, skeletonizing most of the new growth before the first Sevin application, resulting in the most damage. This may have resulted in poor growth of the USDA/NA selections in 1994.
Growth of Silver Maple and Boxelder Taxa in Tennessee
Authors: Witte W.T. , Sauve R.J. , Flanagan P.C.
Published: February 2019

Several commercially available Acer saccharinum and A. negundo taxa were established with 10 single-plant replications in a cultivar trial at the TSU–NCRS in 1993 and 1994. Each plant was fertilized in spring and early summer with 100 gm 15–15–15 beginning Summer 1993. Drip irrigation was applied as needed beginning Summer 1993. Vegetation within tree rows was controlled with preemergent and postemergent herbicides, while grassed middles were mowed. Growth data were recorded in Fall 1993 and 1994 and height and caliper increment calculated for the 1994 season. In the silver maple group with most height growth were: `Silver Queen', `Skinneri', and `Silver Pyramid'. These differed significantly from a group of four slower growing cultivars. Cultivars with the most height growth also had the most caliper growth. Seedling boxelder grew faster than one accession of `Flamingo', while three other cultivars were intermediate. Data will also be presented on insect and disease ratings.
Powdery Mildew Observatios and Growth of Crapemyrtle in Teneessee
Authors: Windham M.T. , Witte W.T. , Sauve R.J. , Flanagan P.C.
Published: February 2019

Fifty-five cultivars of crapemyrtle were established in a cultivar trial with 10 single-plant replications during Fall 1993 and Spring 1994. Drip irrigation began on a regular basis on 18 May 1994 and plants were fertilized regularly. Powdery mildew appeared in July, and within 2 to 3 weeks maximum levels of infection occurred. Plants were rated using a scale of 0 (healthy) to 5 (totally mildewed). In the group of seven cultivars, most heavily infected (>2.8 rating), `Byers Wonderful White' was worst (4.1), followed by `Royalty', `Pink Lace', `Prairie Lace', `Petite Plum', `Firebird', and `Christmastime'. There were 21 cultivars with no mildew (0.0). Many of these were USDA–NA hybrids but also included `Hope', `Bourbon Street', `Glendora White', `Petite Snow', `Centennial Spirit', and `Hardy Lavender'. A few USDA–NA hybrids had slight mildew: `Potomac', `Powhatan', `Catawba', `Seminole', `Biloxi', and `Hopi' (<10% of foliage mildewed).
Postharvest Changes of Carambola Fruit (Averrhoa carambola L.) Picked at Different Ripening Stages
Authors: Siller J. , Muy M. , Araiza E. , Báez M. , Garcia R. , Báez R. , Diaz J.
Published: February 2019

Carambola fruit collected at the dark-green, light-green, color-break, and ripe stages were evaluated during storage at 21C for up to 10 days. Fruit size, weight, postharvest changes in color, compositional characteristics, CO2 production, ethylene evolution, and weight loss were monitored daily. Fruit size ranged between 78 to 82 mm. Peel color luminosity and chroma values increased with maturity stage, while hue values decreased. However, hue and chroma values of the four ripening stages tended to decrease with storage time. Weight loss and fruit flesh firmness were both affected by storage time and ripening stage, and ranged among the maturity stages from 5.1% to 6.7% and from 2.11 to 0.94 kg-f, respectively. On dark-green fruit, total soluble solids and titratable acidity were 4.89° Brix and 0.808%, respectively. Fruit collected at the ripe stage presented values of 6.7° Brix and 0.412% titratable acidity. None of the fruit among maturity stages changed significantly during storage on these parameters. Carbon dioxide production increased from 6.06 to 21.83 ml CO2/kg-h during storage time among maturity stages and always was highest on ripe fruit. Fruit harvested at the color-break and ripe stages produced ethylene after 9 and 6 days, respectively, and ranged from 1.15 to 3.92 μl·kg–1·h–1.
Some Ripening Changes during Storage and Ripening in Wax-coated Mangoes
Authors: Zambrano Judith , Briceño Sagrario , Pacheco Lidis , Méndez Clara
Published: February 2019

`Palmer' and `Keitt' mangoes (Mangifera indica L.) were treated with two commercial wax coatings. The fruit were placed in 20-liter plastic containers, stored at 5C, and 85% to 95% relative humidity. Fruit were dipped fully in 1% aqueous suspensions of Pro-long and Primafresh C (original concentration) and analyzed at 2-day intervals for 18 days, with day 0 being 24 h after harvest. The following parameters were monitored: peel and pulp color (L*, chroma, and hue), fresh weight loss, total soluble solids, and titratable acidity. Both waxes reduced the rate of loss fresh weight of mangoes as compared with uncoated fruit. No differences were found for titratable acidity and total soluble solids. Waxed fruit were lighter (higher L* values) and less intense (lower chroma values) in color than control fruits.
Cell Wall Degradation in Irradiated Tomato Fruit
Authors: El-Assi N. , Huber D.J. , Brecht J.K.
Published: February 2019

The irradiation of harvested fruit is typically accompanied by excessive tissue softening, a process that is not well understood. In this study, we examined the role of specific cell wall polymers and the extent of general cell wall degradation and softening in irradiated tomato fruit. `Sunny' tomato fruit at mature-green and pink stages were subjected to X-ray radiation at 0, 83, and 156 Krad. Immediate softening was noted for both maturation classes, although some postirradiation recovery was evident in green fruit. Pectic polymers of both mature-green and pink fruit exhibited depolymerization and altered neutral sugar profiles in response to irradiation. Pectins, either as components of total ethanol-insoluble solids (EIS), purified by selective extraction, or of commercial origin were similarly affected by irradiation. Cellulose preparations were unaffected by irradiation. The data demonstrate that the effect of irradiation on the cell wall exhibits specificity, can occur nonenzymatically, and does not require initiating adducts of cytosolic origin.
The Effect of Delayed Cold Storage and Controlled-atmosphere Storage on Chilling Injury in Nectarines
Authors: Skog L.J. , Smith R.B. , Murr D.P.
Published: February 2019

`Fantasia' nectarines (Prunus persica L.Batsch) were either stored immediately at 0.5C or subjected to a 48-h delay at 20C in air or with 5% CO2 in air before storage. Samples were evaluated at harvest and after 18, 25, 32, 39 and 46 days storage in air or in 5% O2 with 0%, 4%, 8%, or 12% CO2. All samples were evaluated at optimum ripeness. A combination of delayed storage and elevated CO2 in storage effectively delayed chilling injury (CI) symptoms. Control of CI increased with increasing CO2 level in delayed and nondelayed treatments. Delayed storage was not effective without elevated levels of CO2 in the storage atmosphere. Fruit that was stored without delay did not soften normally during the ripening period and developed a dry, rubbery texture. The effect was enhanced as CI progressed, resulting in increased firmness of ripened fruit with increased storage time. The delayed storage treatments softened normally during ripening, but CI fruit had a dry, mealy texture. Internal conductivity measurements correlated well with CI development. Off-flavors were detected at the higher levels of CO2 storage.
Modified-atmosphere Packaging of `Sweetheart' Cherries
Authors: Meheriuk M. , McKenzie D.-L. , Girard B. , Moyls A.L. , Weintraub S. , Hocking R. , Kopp T.
Published: February 2019

Kilogram quantities of `Sweetheart' cherries were stored in HDPE perforated bags (1993, 50.8 μ thickness, OTR = 750 ml·m–2·day–1) or in nonperforated bags (1994, 11 μ thickness, OTR = 5196 ml·m–2·day–1) at 0C. Samples were removed at 1, 2, 4, and 6 weeks of storage and evaluated for fruit and sensory quality. Bag atmospheres after 6 weeks of storage were 10% CO2 and 4.6% O2 for the perforated bags and 3.5% CO2 and 6.6% O2 for the nonperforated bags. Fruit brightness, firmness, and titratable acidity declined during storage. Skin color tended to be redder with the longer storage periods. Sensory evaluation in 1993 showed a decline in overall appearance and flavor with time, but texture and juiciness did not change. Acceptability remained high for the first 4 weeks of storage but dropped at week 6. Surface pitting was noticeable at weeks 4 and 6, particularly from stem bruising.
Physiological Changes during Maturation, Ripening, and Storage of Asian Pears Grown in Southeastern United States
Authors: Rajapakse Nihal , Newall William C.
Published: February 2019

Morphological and physiological changes during maturation and ripening of eight Asian pear cultivars grown in the southeastern United States were evaluated. Fruit size increased throughout maturation. Flesh firmness decreased as fruit matured and averaged ≈30 to 35 N at harvest maturity. The average TSS in mature fruit ranged from 10% to 13%, with `Shinko' having the lowest and `Shinsui' having the highest. TSS increased during 4 weeks of storage at 1C, but the increase was greater in immature fruit than in mature fruit. Respiration rate declined as fruit matured. Ethylene production was low in `Hosui', `Kosui', `Nijisseiki', `Shinseiki', `Chojuro', and `Shinko' fruit. Mature `Ichiban' and `Shinsui' fruit produced high amounts of ethylene. `Kosui', `Shinsui', `Chojuro', and `Ichiban' fruit showed a climacteric rise in respiration and ethylene production at 20C, while `Hosui', `Nijisseiki', `Shinseiki', and `Shinko' behaved as nonclimacteric fruit. Ethylene production by 1C-stored `Kosui', `Shinsui', `Chojuro', and `Ichiban' fruit was increased on removal to 20C. Glucose and fructose were low during early maturation but sharply increased ≈80 to 85 days after full bloom (DAFB). Sucrose was low in immature fruit but accumulated rapidly late in maturation ≈100 to 107 DAFB. In mature `Hosui', `Kosui', `Nijisseiki', `Shinsui', `Shinko', and `Ichiban' fruit, fructose was the predominant sugar, while in `Shinseiki' and `Chojuro' fruit, sucrose was the predominant sugar.
Relationships between Textural and Structural Differences of Various Apple Cultivars during Cold Storage
Authors: El-Shiekh Ahmed F. , Tong Cindy B.S. , Luby James J. , Hoover Emily E.
Published: February 2019

The relationships between cellular characteristics of cortical tissue and changes in texture during storage under controlled atmosphere (CA, 3% O2 + 3% CO2) or air at 0C were studied. The cultivars used were `Delicious', `Cortland', `Honeycrisp' and its parents, `Honeygold' and `Macoun'. The force needed to break a 7-mm cylinder of apple flesh (breaking force) was greatest for `Delicious' and `Honeycrisp'. Scanning electron microscopy demonstrated that tissues of firm-fleshed cultivars (`Honeycrisp' and `Delicious') fractured through cells, while that of soft-fleshed cultivars (`Cortland', `Honeygold', and `Macoun') fractured between cells. `Honeycrisp' had fewer cells/100 cm2 than the other cultivars. After 9 months of storage, breaking force, cell size, and K+/Ca2+ decreased, while cell number/100 cm2, Ca2+ content, and K+ content increased for all cultivars. Cell number/100 cm2 was significantly less and breaking force was significantly greater for tissue from CA than air-stored fruit.
Response of Respiration Rate, Ethylene Production, and Membrane Permeability to Vibration in Fig Fruit
Authors: Mao Lichun , Ying Tiejin
Published: February 2019

Changes in respiration rate, ethylene production, and membrane permeability of fig (Ficus carica L. `Masui Dauphine', `Celeste', and `Brunswick') fruit subjected to vibration at acceleration of 4x g for 10 min were investigated. Vibration increased respiration rate significantly, which, however, declined quickly to low level soon after the treatment. Ethylene production and membrane permeability also increased significantly during vibration. However, vibration stress up to 4x g did not have significant effect on the physiological changes of the fig fruit after vibration. `Masui Dauphine' is more susceptible to vibration stress than `Celeste' and `Brunswick'.
Role of β-Galactosidase, Cellulase, Pectinesterase, and Polygalacturonase in Pectin Solubilization in Ripening Rabbiteye Blueberries
Authors: Woods F.M. , Kotrola J.S. , Himelrick D.G. , Brasher T.M. , Basiouny F.M.
Published: February 2019

Fruit of two rabbiteye blueberries (Vaccinium ashei Read cvs. Premier and Tifblue) were analyzed at five stages of growth and development for cell wall softening enzymes in relation to pectin solubilization. The enzymes examined were β-galactosidase, cellulase, pectinesterase, and polygalacturonase. The decrease in fruit firmness was associated with increased activities of cellulase, polygalacturonase, and pectinesterase, which preceded the former enzymes. The activity of β-galactosidase remained relatively unchanged throughout. The pattern of enzyme activities from both cultivars were similar. Results from this study indicate that these enzymes may play a crucial role in overall fruit shelf life and hence postharvest marketing duration.
Leptine-based Resistance to Colorado Potato Beetle among Interspecific Hybrids of Wild Potato
Authors: Rangarajan Anusuya , Miller A. Raymond , Veilleux Richard
Published: February 2019

Leptine (LP) glycoalkaloids have been demonstrated to confer natural resistance to the Colorado potato beetle (CPB) in Solanum chacoense (chc). Development of cultivated potatoes with natural resistance to CPB has the potential to reduce both costs and environmental impacts of production by reducing pesticide use. To introgress the genes conferring leptine production from chc into S. tuberosum (tbr), clones of chc have been crossed with clones of S. phureja. Leaf disks from eight hybrids were subjected to a CPB second instar feeding bioassay to determine if extent of feeding was related to LP levels. Most hybrids contained leptinidine (LD, the aglycone of LP) levels intermediate to chc and tbr, and insect feeding was suppressed 30% to 50% in hybrids containing >10 mg·g–1 DW LD. One hybrid displaying feeding suppression contained a very low level of LD, whereas another hybrid that contained higher levels of LD had higher feeding rates. The presence of LD at “threshold” levels in these hybrids will suppress feeding of CPB, but other factors affecting resistance are also present and need to be explored.
Developing Cover Crops for Weed Control in Establishment Year for Strawberries
Authors: Herman Charlotte , Larson David , Hoover Emily
Published: February 2019

The goal of our program is to learn how to effectively establish first-year strawberry plantings without using herbicides. Before strawberry transplanting, four treatments were established: winter wheat, a dwarf Brassica sp., napropamide (2.24 kg·h–1) plus hand hoeing and rototilling, and no weed management. `Honeyoye' transplants were set into plots measuring 6.1 × 7.32 m on 21 May 1993 and 10 May 1994. Weekly data was taken on the percentage of soil area covered with plant material, height, and stage of development of plants, and weeds present. Weed transects and plant dry weights were done periodically during the growing seasons. The most promising cover crop treatment was the dwarf Brassica sp. for early season weed suppression because of rapid germination and short stature. Winter wheat was very competitive with the strawberry plants. The herbicide treatment had the largest inputs; however, it did produce the largest strawberry plants at the end of the season.
Comparison of Two Methods to Evaluate Water Use by Row Middle Cover Crops in Fruit Plantings
Authors: Lakso Alan N. , Pool Robert M. , Dunst Richard , Fendinger Andy
Published: February 2019

Cover crops are of increasing interest in fruit plantings. Previous studies indicated that, in unirrigated New York vineyards, effects of row middle cover crops is primarily competition for soil water. Row middle management trials in `Concord' vineyards compared cover crops (orchardgrass, bluegrass, vetch, clover, and rye) to straw mulch, bloom glyphosate, and cultivation for water use patterns. Neutron probe tubes within each plot were read weekly at 15-cm intervals down to 120 cm. A second method to examine water use patterns used double florist pots with native soil sunken within the plots to provide a removable sample of the cover. These pots were lifted and weighed at intervals to examine in situ water use. The pot weight loss data generally correlated well with the neutron probe data. Precautions are needed related to differences in natural rooting depth, more rapid drying of pot vs. normal soil volume and representativeness of plant cover and health. The neutron probe method gives more complete data, but the pot method may be a useful simple, inexpensive method of examining relative water use patterns of cover crops with natural boundary layers that exist in discontinuous fruit plantings.
Inheritance of Leptine Glycoalkaloids in Solanum chacoense
Authors: Kobayashi Ruth S. , Sinden Stephen L. , Sanford Lind L.
Published: February 2019

Leptine glycoalkaloids found in certain genotypes of Solanum chacoense, a wild potato relative, are resistance factors against the Colorado potato beetle (CPB). To efficiently introgress CPB resistance through leptine production into the cultivated potato, an understanding of leptine inheritance is important. Analysis of sibs within PI lines revealed a wide segregation for level of leptines. Leptine levels ranged from not detectable to 120 mg/100 g fresh weight among six sibs in a PI line, suggesting leptine production may be controlled by a few major genes. TLC analysis of F2 and backcross progeny, however, indicated that several genes probably control leptine level. This apparent multigene control of leptine level may make it difficult to incorporate leptine synthesis into the cultivated potato. Therefore, we are presently identifying microsatellite and RAPD markers associated with leptine synthesis to enable marker-assisted selection and facilitate the incorporation of leptine synthesis into the cultivated potato.
Inheritance of Resistance to Xanthomonas campestris pv. vesicatoria Race T3 in Tomato
Authors: Scott J.W. , Jones J.B. , Somodi G. Cameron , Stall R.E.
Published: February 2019

Resistant Hawaii 7981 (P1) was crossed with susceptible Fla. 7060 (P2), and F1, BCP1, BCP2, and F2 generations were obtained. Hypersensitive reactions (Hr) were measured 24 and 48 hours after inoculation in growth chambers at 24 and 30C. At 30C, there was no Hr. At 24C and 24 hours, 100% of Hawaii 7981 plants, 54.2% of BCP1 plants, and 21.7% of F2 plants had Hr. At 24C and 48 hours, 100% of Hawaii 7981, the F1, and BCP1 plants; 50% of BCP2 plants; and 73.3% of F2 plants had Hr. Other plants were inoculated and rated for race T3 in the field. Disease for each generation was significantly different (P < 0.05) and their order from most to least resistant was P1, BCP1, F1, F2, BCP2, and P2. The F1s were distributed between the parents with slight overlaps. BC plants had bimodal peaks similar to the F1 and their respective parents. The F2 had three peaks corresponding to P1, F1, and P2. The data suggest Hr and field resistance are controlled by the same incompletely dominant gene.
Zucchini Yellow Mosaic Virus in Colima, Mexico: Effect on Flowering and Yield of Muskmelon and Transmission by Aphids
Authors: Orozco-Santos Mario , Delgadillo-Sanchez Felipe , Arenas-Varga Miguel , Farias-Larios Javier
Published: February 2019

Zucchini yellow mosaic virus (ZYMV) infection causes heavy losses in cucurbit crops grown in the Mediterranean, Central Europe, the United States, and Mexico. Recently, ZYMV was found affecting muskmelon (Cucumis melo L.) in Colima, Mexico. An experiment was carried out under dry tropical conditions with the objectives: 1) to determine the effect of ZYMV on flowering and yield of muskmelon cv. Primo, and 2) to evaluate its transmission by some aphid species. Perfect and staminate flowers were significantly reduced when ZYMV was inoculated during vegetative growth, flowering, and fruit set. ZYMV affected yield when it was inoculated from vegetative growth to flowering and fruit set. In plants inoculated during vegetative growth the yield was null, while those inoculated at early flowering and fruit set the yield was reduced by 80% and 49%, respectively. The yield was not affected when ZYMV was inoculated on fruit growth. The aphid Myzus persicae, Aphis gossypii, A. spiraecola, and Uroleucon ambrosia-transmited ZYMV from Cucurbita pepo to Cucumis melo; but Aphis nert, did not.
Reducing Deer Damage to Woody and Herbaceous Plants
Authors: Lutz James
Published: February 2019

Woody and herbaceous plants in urban and rural landscapes, nurseries, orchards, and Christmas tree plantations are becoming increasingly susceptible to deer damage. Most existing repellents are either ineffective, or are effective for short periods of time. This project presented four plant species treated with chicken eggs, Deer-Away, Hinder, Tree Guard, Milorganite, chicken eggs with Tree Guard, and chicken eggs with Transfilm, to 20 captive white-tailed deer (Odocoileus virginianus). Only chicken eggs alone and Deer-Away deterred deer from feeding on the containerized nursery stock. Chicken eggs alone performed significantly better than Deer-Away. In a second experiment, pelletized deer food treated with Deer-Away, Hinder (1:1 and 1:5), Tree Guard, Miller Hot Sauce (0.62% and 6.2%), and two experimental predator urines were presented to ten captive deer. Both rates of Miller Hot Sauce and predator urine #1 significantly reduced deer feeding on pelletized deer food. Deer-Away, Hinder 1:1, and predator urine #2 also reduced feeding. Hinder 1:5 slightly reduced feeding. Tree Guard was completely ineffective.
Incompatibility Alleles of Hazelnut Cultivars
Authors: Mehlenbacher Shawn A.
Published: February 2019

Incompatibility in hazelnut (Corylus avellana L.) is of the sporophytic type and is under the control of a single S-locus with multiple alleles. Tests in recent years have identified four new alleles, bringing the total to 26. Improved pollen testers have been identified for several alleles. The S-alleles of more than 90 cultivars have been identified by fluorescence microscopy and will be presented. These cultivars (and their alleles) include Tonda di Giffoni (2 23), San Giovanni (2 8), Gasaway (3 26), Gunslebert (5 23), Kadetten (20 25), Lang Tidlig Zeller (4 20), Nocciolino Sangrato (7 17), Rode Zeller (6 11), Segorbe (9 23), and Simon (6 22).
Relationships of Fruit Development Period, Seed Germination, Seedling Survival, and Percent Dry Weight of Ovule in Peach
Authors: Bacon T.A. , Byrne D.H.
Published: February 2019

A study was conducted on various peach [Prunus persica (L.) Batsch.] cultivars to determine the relationships among seed germination, seedling survival, seedling rosetting, fruit development period (FDP), and percent dry weight of the ovule (PDO). Germination and survival increased rapidly between 80 and 100 days of FDP, corresponding to an increase in mean PDO from 16% to 50%. Germination and survival leveled off after 105 days of FDP at >85%, corresponding to a mean PDO of 64%. Rosetting was high among seedlings for cultivars with FDP <110 days, but dropped rapidly as FDP increased. PDO was found to be a better indicator of seed germinability and seedling survival than FDP.
Botryis-induced Postharvest Losses of Cut Roses May be Reduced by Electron-bean Irradiation
Authors: Chang Ai-Yu , Gleason Mark L. , Agnew Nancy H. , Olson Dennis G. , Gladon Richard T.
Published: February 2019

Irradiated cut Rosa × hybrida `Royalty' flowers were used to determine the efficacy of electron-beam irradiation for extending flower postharvest life by reducing native and inoculated populations of Botrytis cinerea. In preliminary experiments, roses received irradiation dosages of 0.00, 0.50,1.00, 2.00, and 4.00 kilogray (kGy), along with an untreated control, to establish killing dosages. Irradiation dosages of 1.00 kGy or greater irreversibly damaged rose petal tissue. In subsequent experiments, roses irradiated at dosages of 0.00, 0.25, 0.50, 0.75, and 1.00 kGy, and an untreated control, were used for evaluating postharvest events. We have found that irradiation dosages of 0.25 and 0.50 kGy slowed the rate of flower bud opening slightly and did not decrease postharvest quality or longevity. Inoculated and uninoculated roses irradiated at 0.00, 0.25, 0.50, and 0.75 kGy were used to determine if electron-beam irradiation could reduce Botrytis infection and proliferation during postharvest storage, and these results also will be presented.
Water Use of Container-grown Geraniums and Petunias
Authors: Panter Karen L.
Published: February 2019

Two studies were undertaken to quantify the amount of water used by two container-grown bedding plant crops. Petunia × hybrida cv. Welby Blue and Pelargonium × hortorum cv Red Satisfaction plants were grown in 11-cm pots in a commercial greenhouse in Denver, Colo. In Expt. 1, rooted geranium cuttings and petunia seedlings were planted in Fafard #2, a growing medium containing peat, perlite, and vermiculite. Half of the plants were grown with the substrate covered. Each pot was weighed just prior to, and again 24 h, after watering. Measured amounts of water were applied to the pots. Geraniums in uncovered pots lost an average of 1.7 kg/pot over 59 days. Geraniums in covered pots lost an average of 1.6 kg/pot. Petunias, over 23 days, lost 730 g per uncovered pot and 623 g per covered pot. Experiment 2 compared water loss in growing medium amended with five different hydrophilic gels, and a control with no gel added. With geraniums, no differences were found among treatments in total water loss, initial or final plant height, or fresh or dry plant weight. With petunias, no differences occurred in initial or final height, or fresh or dry weight. There was a difference between two of the gel treatments in total amount of weight lost.
Using RAPD Markers to Assess Genetic Diversity in Brassica Germplasm and Chinese Breeding Lines
Authors: Hou Anfu , McFerson James R. , Lamboy Warren F.
Published: February 2019

Molecular DNA markers based on the RAPD (random amplified polymorphic DNA) assay are gaining use in germplasm assessment. RAPD markers are simple, relatively inexpensive, and highly informative. We used five primers to assess 26 Brassica oleracea breeding lines from the IVF and nine accessions from the PGRU. The test array included eight subspecies of B. oleracea. We generated 90 RAPD markers and were able to unambiguously discriminate among all 35 test entries, but could not separate subspecies within B. oleracea. Genetic similarity between subspecies ranged from 0.629 to 0.738. Average similarity within accessions was 0.96, confirming the suspected homogeneity of breeding lines. Nevertheless, significant genetic diversity was found among kohlrabi, broccoli, and cabbage accessions. Similarity analysis of breeding lines and hybrids confirmed their pedigree relationships. Interestingly, B. o. subsp. costata `Couve Nabica' showed closer similarity to B. napus subsp. oleifera `Jet Neuf' than to other B. o. materials and B. o. subsp. italica `Packman' showed higher similarity to some cabbages than to other broccolis. Results provide further evidence that diversity assessment using RAPDs is broadly applicable and useful in germplasm conservation and utilization.
Molecular Markers and Linkage to the Sw-5 Locus for Resistance to Tomato Spotted Wilt Virus (TSWV)
Authors: Stevens M.R. , Griffiths P.D. , Scott J.W. , Heiny D.K. , Rhoads D.D
Published: February 2019

Sw-5 is a locus introgressed from Lycopersicon peruvianum to some L. esculentum lines conferring dominant resistance to TSWV. Restriction fragment length polymorphism (RFLP) analyses positions Sw-5 to the long arm of chromosome 9 in the sub-telomeric region between CT71 and CT220. RFLP analyses suggest the introgressed region begins distal to CT71, includes CT220, and may extend to the telomere. Randomly amplified polymorphic DNA (RAPD) analyses with >700 random 10-mer primers identified a single 2.2-kbp band with one primer (primer #72 GAGCACGGGA) that is tightly linked to Sw-5. However, we have also produced an equivalent 2.2-kbp band in analysis of other TSWV-susceptible tomato breeding lines. Thus, this band likely derives from L. esculentum DNA very near to Sw-5 and the introgressed region. Additional analyses have recently detected a potential co-dominant RAPD polymorphism linked to Sw-5.
Potassium Nitrate Controls Pecan Sprout Regrowth in Stumps after Orchard Thinning
Authors: Chapman Dan , Sistrunk Laurence , Storey J. Benton
Published: February 2019

Stumps remaining after tree removal during orchard thinning will characteristically produce extensive shoot growth in response to the massive root systems that previously supported large trees. A 38-year-old pecan orchard was thinned from 15 × 15 m to 21 × 21 m. Stumps ranging from 45 to 65 cm in diameter were treated in seven replications with 0.19, 0.37, and 0.75 kg KNO3, respectively, per stump in drilled holes. Two controls consisted of stumps with drilled holes and intact stumps with no holes. Eight holes per stump were drilled with a 2.54-cm-diameter power auger to a depth of 15 cm. The number and weight of regrowing sprouts was measured annually. The 0.75 kg KNO3 rate significantly reduced the number and weight of sprouts regrowing the first year. The drilled stumps showed a significant decrease in new sprouts over the undrilled control. The low KNO3 rate stimulated regrowth. The key to regrowth suppression is to use a high rate of KNO3 in sufficient holes to allow penetration. KNO3 stump treatment should be a safe practice because no more than, perhaps, 2.25 kg of KNO3, depending on trunk diameter, will be used per site, which will then provide nutrients to existing trees as it dissipates.
Relative Vigor Following a Severe Freeze of 18 Wine-grape Varieties at Brownfield, Texas
Authors: Pittcock J. Kim , Durham Richard E. , Mitchell Roy E. , Lipe William L. , Elkner Timothy E.
Published: February 2019

Texas Tech Univ., in collaboration with the Texas Agricultural Experiment Station, Lubbock, maintains a research vineyard at Brownfield. Texas. Thirty-one wine-grape varieties are being evaluated for performance on the Texas High Plains. The vines were planted on their own roots in a completely randomized design with four replications and two plants per replication. The average rainfall, including supplemental irrigation, was ≈550 mm/year. Sufficient data exist for comparison of 18 varieties during the 1992–1994 seasons, following a severe freeze in Nov. 1991. The vines were trained to a horizontal bilateral cordon and spurpruned with two buds per spur and 10 to 12 spurs per vine. Pruning weights were taken from the surviving vines during the 1993–1995 dormant seasons. Pruning weights were used as a direct estimate for plant vigor. The varieties exhibiting lowest vigor included `Carmine', `Pinot Blanc', `Pinot Noir', and `Ruby Cabernet', while those exhibiting highest vigor included `Semillion', `Chenin Blanc', `Muscat Canelli', and `French Columbard'.
Effect of Double Anti-fog Claddings on Greenhouse Energy Consumption, Microclimate, and Cut-flower Growth
Authors: Zhang Y. , Gauthier L. , de Halleux D. , Dansereau B. , Yelle S. , Gosselin A.
Published: February 2019

qA 3-year study was undertaken to quantify the effect of four greenhouse covering materials on energy consumption, microclimate, and the growth and production of cut flowers Matthiola incana (Stocks) and Antirrhinum majalis (Snapdragons) in the greenhouse. The four materials are single glass (GL), polyethylene (PE) + anti-fog 1-year polyethylene (AF1), polyethylene + antifog 3-year polyethylene (AF3), and polyethylene + anti-fog thermal polyethylene (AFT). The effect of thermal screen and supplementary lighting (60 μmol·m–2·s–1) also are discussed. This study indicated that AFT film is the most energy efficient material and AF3 film is the most transparent to photosynthetic active radiation (PAR). For stocks, good quality can be obtained in GL and AF3 in terms of spike length, stem diameter, as well as number of buds and flowers. The stocks in GL, however, always possess the highest photosynthetic capacity, regardless light treatment. For snapdragons, the growth and flowering in PE houses were significantly improved by supplementary lighting
Factors Contributing to Cuticle Cracking in Greenhouse Tomato Fruit
Authors: Ehret David L. , Helmer Tom
Published: February 2019

Cuticle cracking (also known as russeting, rain checking, or shrink cracking) can significantly reduce the quality of greenhouse-grown tomatoes, adversely affecting appearance and shelf-life. In this study, the effects of several environmental and cultural factors on cuticle cracking were assessed. Plants (`Trust') were grown at one of three nutrient feed concentrations, with electrical conductivities (ECs) of 0.7, 2.0, and 4.0. Higher EC initially reduced the amount of cuticle cracking. Over 14 weeks, the amount of cracking increased in all treatments and the differences due to EC became less evident. Over this same interval, 24-h average relative humidity (RH) gradually increased and was correlated with the increase in cracking. Further analysis showed that this relationship was due primarily to an increase in nighttime RH. No other climatic conditions were related to cracking. To test the possibility that the increasing age of the crop also could have contributed to the increased cracking over time, two crops of different ages grown in the same greenhouse were evaluated for cuticle cracking. The older crop consistently showed a greater amount of cracking than the younger crop. Our data suggest that EC is useful in controlling cuticle cracking under some conditions, but that nighttime RH or possibly some factor associated with crop maturity may override the effects of EC.
Energy Consumption Due to Dehumidification of Tomato Greenhouses under Northern Latitudes
Authors: de Halleux Damien , Gauthier Laurent
Published: February 2019

Transpiration and water uptake play an important role in the growth of horticultural crops, such as tomatoes. Water uptake ensures the transport of nutrients. However, the transpiration rate is affected by the humidity level in the greenhouse. High levels of humidity restrict transpiration and lead to fungal diseases resulting in yield losses. Under northern latitudes, using more airtight structures combined with high levels of artificial lighting increase the humidity level inside the greenhouses. To decrease humidity, growers have to dehumidify by ventilating and heating at the same time, leading to increased energy consumption. However, to our knowledge, the literature does not report on the energy consumption needed to dehumidify. To evaluate this energy consumption, we used a greenhouse simulation model of heat and mass exchanges integrated into a general greenhouse control and management software system (GX). Evapotranspiration, condensation on the cladding, and infiltration and ventilation rates were taken into account for the water balance. Based on 1 year of climatic data, three sets of simulation were realized: 1) no dehumidification; 2) standard dehumidification by ventilation and heating; 3) dehumidification with heat exchangers. Results indicate that for an acceptable level of humidity within a greenhouse tomato crop (vapor pressure deficit >5 kPa), the energy consumptions with standard dehumidification and with heat exchangers are 25% and 15% higher, respectively, than without dehumidification. These results are being used to establish recommendations for the management of humidity under northern latitudes.
Effects of Cultivars and Culture Systems on Yield and Postharvest Quality of Greenhouse Tomato
Authors: Gagnon Serge , Mzouri Mohamed , Gosselin André
Published: February 2019

Our purpose was to determine cultivar and culture system effects on yield and postharvest quality of greenhouse tomato Lycopersicon esculentum. Nine tomato cultivars were sown into rockwool cubes on 2 Feb. 1994. The plants were transplanted into peat bags or nutrient film (NFT) systems on 9 Mar. Harvesting began on 2 May until 26 Sept. for a total of 21 harvest weeks. Fruit yield, rejected or nonmarketable fruit and four fruit quality indicators (fruit texture, color, titrable acidity, and soluble sugars) were measured during the harvest period. In addition, these indicators were further evaluated every 7 days during 28 days of storage at 20C and 90% RH for `Trust' and `Cencara', a long shelf-life cultivar. `Bounty', `Panther', and `Cencara' gave higher yields on rockwool but `Irazu', `Correct', `73-53', and `Medallion' gave better results on NFT. `Trust' produced the best yield for either rockwool or NFT. Culture systems (peat bags or NFT) did not affect fruit quality. `Cencara', which is a long shelf-life cultivar, kept high texture quality until 28 days of storage. However, titrable acidity of `Cencara' was higher and soluble sugars content was lower than that of `Trust'
Irrigation Scheduling, Nutrient Application Frequency, and Freezing Acclimation of `Hamlin' Orange Trees in Florida
Authors: Tignor Milton E. , Davies Frederick S. , Sherman Wayne B.
Published: February 2019

`Hamlin' orange trees [C. sinensis (L.) Osb.] from a commercial nursery were planted into raised beds on a site that simulated conditions typical of the flatwoods region of the citrus industry. A factorial experiment with three irrigation schedules, based on growth flushes and three nutrient application frequencies (total N, 0.136 kg/tree per year), was conducted in 1994. Trees were irrigated using 90° microsprinklers, and soil moisture content was monitored using a neutron probe. Eleven replicate trees of the nine treatments were included in a completely randomized block design. Weekly freeze tests using the electrolyte leakage method were conducted at –4, –6, and –8C. Electrolyte leakage was determined using a conductivity meter. Different irrigation scheduling based on growth flushes had no significant effect on freezing acclimation. However, increased frequency and lower amounts of fertilizer per application significantly (P = 0.05) increased freeze hardiness from 4.2 to –6.10C by the end of November. Morphological data including trunk diameter, tree height, and flushing status also were recorded. Increasing frequency of nutrient application resulted in a more rapid acclimation of young `Hamlin' orange trees.
Cold Hardiness of Evergreen Azaleas Increased by Water Stress Imposed at Three Days
Authors: Anisko Tomasz , Lindstrom Orville M.
Published: February 2019

The effect of water stress on cold hardiness was examined in evergreen azaleas, `Coral Bell' (CB), `Hinodegiri' (HD), and `Red Ruffle' (RR). Plants were well-watered between 8 Aug. and 1 Nov. (wet) or were subjected to 3 weeks of reduced water supply starting on one of three dates, 1 Aug. (dry 1), 29 Aug. (dry 2), and 19 Sept. (dry 3). Cold hardiness of leaves and lower, middle, and upper stems was tested on 29 Aug., 19 Sept., 10 Oct., 1 Nov. By the end of each 3-week period, water potential of water stressed plants reached –1.5 to –1.8 MPa compared to around –0.8 MPa of well-watered plants. Reducing the water supply significantly increased cold hardiness of all tested plant parts in all cultivars regardless of timing of watering reduction, with two exceptions, CB middle stems on 29 Aug. and HD leaves on 19 Oct. Three weeks after rewatering cold hardiness of water-stressed plants did not differ significantly from well-watered plants, except for HD plants under dry three treatment, which continued to be 1.0 (middle stems) to 4.3 (upper stems) more cold hardy.
Evaluation of a Green Roof System in a Northern Climate: The Effects of a Roof Microclimate on Growth and Development of Six Herbaceous Perennials
Authors: Boivin Marie-anne , Dansereau Blanche , Gosselin André
Published: February 2019

Green roof systems are now common in many European countries. Aside from aesthetic considerations, these systems present many environmental advantages in urban planning ecology. A flat roof surface (250 m2) was rebuilt on the top of a 30-year-old building. Our objective was to determine the effects of roof microclimate on the growth and development of six herbaceous perennials: Ajuga reptans, Arenaria verna `Aurea', Armeria maritima, Draba aizoides, Gypsophila repens, and Sedum Kamtschaticum. Rooted plants were transplanted into an artificial substrate at three depths (5, 10, and 15 cm) in a 36-m2 area. A special protective covering (Soprafiltre) was installed over the growing area. The following result are presented: temperature variations (winter–spring–summer) at crown and root-zone level, plant hardiness, growth index (height × width), and flowering.
Low-temperature Limits for Selected Garden Mums
Authors: Iles Jeffery K.
Published: February 2019

Controlled-freezing tests were conducted in Dec. 1994 and Jan. 1995 to determine cold hardiness of garden mums (Dendranthema grandiflora Tzvelev.) `Baby Tears', `Debonair', `Emily', `Megan', `Ruby Mound', and `Triumph' grown outdoors in central Iowa. Dormant, intact crowns were harvested from the field on 3 Dec. and held at 2 ± 2C until freezing tests began. Crowns were placed in moist cheesecloth, wrapped in aluminum foil, and subjected to –12, –18, –24, or –30C. Cooling was initiated from the storage temperature (2C) at 2 ± 0.5C/h. Treated crowns were allowed to thaw for 24 h at 2 ± 2C. Control and treated crowns then were planted in 3.5-liter (#1) plastic containers using a medium of 2 Canadian sphagnum moss: 2 perlite: 1 field soil (by volume), and transferred to a 21 ± 3C glasshouse for forcing under natural photoperiod. Regrowth data indicate `Ruby Mound' was the least cold hardy selection as most failed to resume growth after exposure to –12C. `Emily', `Megan', and `Triumph' survived exposure to –12C; however, vegetative regrowth was diminished compared to controls. `Baby Tears' and `Debonair' demonstrated no diminution of ornamental utility after exposure to –12C.
The Occurrence of Blackheart Injury in Dwarfing Apple Stembuilders
Authors: Estabrooks E.N. , Embree C.G. , Ju H.Y.
Published: February 2019

Apple trees of the tender cultivar Gravenstein were grown on four promising, dwarfing, stembuilders and two known hardy rootstocks to evaluate hardiness. After eight growing seasons and a “test winter” from 1992 to 1993, trees were subjected to a destructive harvest to assess the amount of blackheart. The extent of blackheart was used as an indicator of sublethal winter injury. The amount of blackheart in the stembuilder trunk was significantly different among stembuilders but not between rootstocks. The stembuilder Bud 9 had more blackheart than Dudley, Lobo, KSC 28, and Ungrafted (Dudley). Similarly, the percentage of blackheart in the scion part of the tree showed differences due to cultivars and stembuilders but no difference due to rootstocks.
Benzyladenine Effects on Cell Division and Cell Size during Apple Fruit Thinning
Authors: Wismer Paul T. , Proctor J.T.A. , Elfving D.C.
Published: February 2019

Benzyladenine (BA), carbaryl (CB), daminozide (DM), and naphthaleneacetic acid (NAA) were applied postbloom, as fruitlet thinning agents, to mature `Empire' apple trees. Although fruit set and yield were similar for BA, NAA, and CB, BA-treated fruit were larger, indicating BA increased fruit size beyond the effect attributable to thinning. BA applied at 100 mg·liter–1 increased the rate of cell layer formation in the fruit cortex, indicating that BA stimulated cortical cell division. The maximum rate of cell division occurred 10 to 14 days after full bloom (DAFB) when fruit relative growth rate and density reached a maximum and percent dry weight reached a minimum. Cell size in BA-treated fruit was similar to the control. Cell division ended by 35 DAFB in the control and BA-treated fruit when percent dry weight and dry weight began to increase rapidly and fruit density changed from a rapid to a slower rate of decreased density. These data support the hypothesis that BA-induced fruit size increases in `Empire' apple result largely from greater numbers of cells in the fruit cortex, whereas the fruit size increase due to NAA or CB is a consequence of larger cell size.
Cytological Evidence for the Sterility of an Interspecific Alstroemeria Hybrid
Authors: Lu Chunsheng , Bridgen Mark
Published: February 2019

Self-pollinations of a diploid (2n = 2x = 16) interspecific hybrid from the cross of Alstroemeria aurea × A. caryophyllaea resulted in no seed set. Pollen viability studies with the hybrid demonstrated that only 5% of the pollen grains were viable. Cytological observations with the hybrid pollen mother cell (PMC) revealed abnormal chromosome behaviors, such as no pairing in Prophase I and Metaphase I, and bridges in the Anaphase I and II. Although the development of microspores appeared normal in shape until the stage of tetrad release, some chromosomes did not remain in the nucleus after completing meiosis, formed isolated groups of 1 to 4, and remained in the cytoplasm. This genetic imbalance of the microspores could be one of the causes for the abortion of the pollen grains in the late stage of development. Additional meiotic cytological studies with colchicine-induced tetraploids (2n = 4x = 32) derived from the hybrid plants showed that chromosome pairings were normal in most cases. However, self-pollination with the tetraploid plants failed to set seeds. These studies with the tetraploids further demonstrate that the sterility of the hybrid is due not only to chromosomal differences, but also to complex genic interactions.
A Comparison of Chloroplast vs. Nuclear Genome Analysis for the Development of a Phylogeny of the Genus Juglans
Authors: Parfitt Dan E. , Badenes M.L. , Fjellstrom R.G.
Published: February 2019

Chloroplast DNA polymorphisms were obtained using a combination of RFLP analysis of total cpDNA and a combination of PCR amplification restriction of a 3.2-kb region of cpDNA described previously. Nuclear genome analysis was conducted using 21 RFLP probes that revealed 192 alleles. Parsimony analysis of nuclear DNA places J. cinerea between J. regia and other Asian species, while Wagner-Distance analysis places all North American species between them. cpDNA parsimony also placed the North American species between J. regia and remaining Asian species, but did not resolve the placement of J. cinerea, because all North American species were monomorphic. Both analyses support an ancient origin for J. regia and multiple migration events between North America and Asia.