bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Responses of Strawberry Fruit to High Carbon Dioxide
Authors: Zhang Jianzhi Jenny , Watkins Chris
Published: February 2019

Postharvest strawberry fruit respond beneficially to 20% CO2 treatment as indicated by enhanced fruit firmness and reduced decay. However, the CO2 treatment also can cause detrimental effects, such as off-flavor, depending on concentration and length of exposure to CO2, temperature, and cultivar. To characterize molecular responses of the fruit to high CO2 treatment, mRNA differential display technique has been used to identify and clone genes differentially expressed in CO2-treated fruit compared with air-treated fruit at both cold storage (2 °C) and room (20 °C) temperatures. Forty-eight differentially displayed cDNA bands have been selected and grouped into four families: CO2-induced at both temperatures, CO2-induced only at low temperature, CO2 induced at room temperature, and CO2-repressed ripening cDNAs. These cDNAs are being cloned and sequenced. Genebank database research indicates that alcohol dehydrogenase, spermidine binding protein, and rbcl gene are being induced, and ripening-associated genes such as ACC synthase and ACC oxidase are found to be repressed by the CO2 treatment. Full length of the genes are being obtained by 5'RACE/cDNA library screening methods. Possible function(s) of the genes in responses of strawberry fruit to CO2, and in relation to other kinds of stress-induced gene expression, will be discussed.
Biological Control of Bacterial Blight of Geranium with H-Mutant Bacteriophages
Authors: Harbaugh Brent K. , Jones Jeffrey B. , Jackson Lee E. , Somodi Gail , Flaherty Joseph E.
Published: February 2019

Bacterial blight, caused by Xanthomonas campestris pv. pelargonii (XCP), is considered the most serious disease of geraniums (Pelargonium × hortorum). A novel approach that uses bacteriophages (phages, viruses that kill bacteria) for the biological control of geranium blight will be presented. Phages were once abandoned as biological control agents due to the emergence of bacterial mutants resistant to the phages employed. However, our approach utilizes a mixture of three to eight different phages including host-range mutants (H-mutants). H-mutants are spontaneously derived from their wild-type parent phages and lyse not only parent wild-type bacteria, but also phage-resistant mutants originating from parent bacteria. Two phages specific for XCP initially were isolated from soil samples from Florida and California. These phages produced virulent reactions in six of 30 XCP strains, and lysogenic reactions in 22 strains. After selection of these phages for increased virulence and additional phages were isolated from MN and UT, 17 phages were evaluated for sensitivity to 21 XCP strains from around the world. Four to 14 phages produced virulent reactions in the 21 XCP strains. Five phages produced virulent reactions in at least 17 XCP strains. A mixture of five phages tested against the 21 XCP strains produced virulent reactions for all 21 XCP strains. Geraniums in 10-cm pots were inoculated with XCP and placed on a greenhouse bench in the middle of 5 non-inoculated plants. After 2 weeks of daily spraying plants with a phage solution (109 pfu phage/ml) or water, there was a 71% reduction in the number of bacterial lesions on phage-treated plants.
Purification and Characterization of 5'-Deoxy-5'-methylthioadenosine Nucleoside from Avocado Fruits
Authors: Xiao Chunlin , Kushad Mosbah M.
Published: February 2019

The polyamine and ethylene biosynthetic pathways utilize methionine as substrate for their biosynthesis. However, methionine pool in fruits and other plant tissues is very limited and is not sufficient to accommodate the amount of ethylene or polyamines that are synthesized during development and senescence. To compensate for the insufficient amount of methionine, plant tissues have evolved a mechanism to salvage 5'-deoxy-5'-methylthioadenosine (MTA), a by-product of polyamine and ethylene biosynthesis, back into methionine. The first enzyme involved in this salvage pathway is MTA nucleosidase. Purification of MTA nucleosidase from mature avocado fruits showed that there are two isozymes of MTA nucleosidase. In this study we will report on the purification of one of the isozymes, MTA nucleosidase I. Using ammonium sulfate fractionation, DEAE-Sepharose, Sephadex G-100 gel filtration, and hydroxyapatite chromatography, the isozyme was purified 3712-fold yielding about 11% protein. The isozyme migrated as a single band of 40 kDa molecular weight on SDS-polyacrylamide gel electrophoresis. MTA nucleosidase I exhibited an optimum pH of 7.2 and optimum temperature of 55 °C. The Km value of the isozyme for its substrate MTA is 7.69 μM and the Vmax is 58.82 × 10–6 μmol·min-1. Incubation of MTA nucleosidase I with analogs of MTA, 2.5 mM ethylthioadenosine and 2.5 mM 5'-S-isobutyl-5'-deoxyadenosine, completely blocked its activity. The isozyme activity was also inhibited by putrescine, spermidine, and spermine.
Effect of Weed Control Methods Upon Soil Physical Properties and Plant Growth
Authors: Henry Paul H. , Chong She-Kong , O'Leary Amy
Published: February 2019

There has been speculation in trade journals that landscape fabrics, while doing a excellent job of weed control, may have a detrimental effect upon growth of landscape plants. A study is in progress to investigate the manner in which applied landscape fabric affects soil aeration, soil temperature, and water infiltration rate over a period of 18 months. The experimental design is a split-plot with main plots specified as composted or non-composted areas. Within each main plot, the design is a randomized complete-block with four blocks and four treatments per block (control, bark mulch, landscape fabric, landscape fabric + bark mulch). Each plot has been planted with herbaceous species so as to allow analysis of treatment effects upon plant growth. Re-dox potential is recorded weekly as a measure of soil oxygen status. Infiltration rate is measured biweekly, and soil temperatures within plots are monitored on a continuous basis. Preliminary results suggest that landscape fabrics limit oxygen exchange and that this may adversely affect plant growth. As the study progresses, an attempt will be made to contrast any adverse effects of landscape fabric with the obvious benefits offered by increased weed control.
Growth Response and Carbohydrate Status of Gibberellin-treated Spectral Filter-grown Chrysanthemum Plants
Authors: Tatineni Anuradha , Maki Sonja L. , Rajapakse Nihal C.
Published: February 2019

Interest in the use of non- (or less) chemical methods to reduce the height of ornamental crops has increased tremendously. Manipulation of greenhouse light quality is one alternative for plant growth regulation. We have shown that eliminating far-red light from the greenhouse environment with liquid CuSO4 spectral filters is effective in reducing the height of a wide range of plants though plant carbohydrate status is also altered under CuSO4 filter. In previous studies, application of GA3 reversed both the reduction of plant height and carbohydrate status of CuSO4 spectral filter grown plants. It has been proposed that GAs enhance the activity of the enzyme sucrose phosphate synthase to regulate carbohydrate levels. In the present study the role of exogenously applied GA19, GA1, and GA3 in overcoming the reduction of plant height and carbohydrate levels was investigated. Chrysanthemum plants were treated weekly for 4 weeks with saturating doses of GA19, GA1 and GA3 (25 μg) or the growth retardants paclobutrazol and prohexadione. GA1 was also applied with paclobutrazol and prohexadione to assess whether response to GAs is altered under CuSO4 filter. GA1 and GA3 promoted growth similarly under control or CuSO4 filter. GA19 was least effective in promoting growth under CuSO4 filter. In summary, these results suggest that gibberellin physiology is altered under spectral filters with the conversion of GA19 a possible point of regulation. The correlation between the carbohydrate status and the growth of the plants will be discussed.
Irrigation of Geraniums with an Automatic Controlled Water Table System
Authors: Buxton J.W. , Ingram D.L. , Jia Wenwei
Published: February 2019

Geraniums in 15-cm pots were irrigated automatically for 8 weeks with a Controlled Water Table (CWT) irrigation system. Plants were irrigated with a nutrient solution supplied by a capillary mat with one end of the mat suspended in a trough below the bottom of the pot. The nutrient solution remained at a constant level in the trough. Nutrient solution removed from the trough was immediately replaced from a larger reservoir. The vertical distance from the surface of the nutrient solution and the bottom of the pot determined the water/air ratio and water potential in the growing media. Treatments consisted of placing pots at 0, 2, 4, and 6 cm above the nutrient solution. Control plants were irrigated as needed with a trickle irrigation system. Geraniums grown at 0,2 and 4 CWT were ≈25% larger than the control plants and those grown at 6 CWT as measured by dry weight and leaf area. Roots of plants grown at 0 CWT were concentrated in the central area of the root ball; whereas roots of plants in other treatments were located more near the bottom of the pot. Advantages of the CWT system include: Plant controlled automatic irrigation; no run off; optimum water/air ratio.
Swine Effluent for Tomato in a Plasticulture Production System
Authors: Cushman Kent , Horgan Thomas
Published: February 2019

Tomato was grown in Fall 1997 with swine effluent or commercial soluble fertilizer in a plasticulture production system. Four cultivars, `Mountain Delight', `Celebrity', `Equinox', and `Sunbeam', were transplanted to raised beds with plastic mulch and drip irrigation. Preplant fertilizer was not applied. Effluent from the Wiley L. Bean Swine Demonstration Unit's secondary lagoon was filtered through in-line screen filters and applied directly to the plants through the irrigation system. Toward the end of each application, sodium hypochlorite was injected in the line to achieve a free chlorine concentration of ≈1%. Clogging of filters or drip emitters did not occur. Control plants received 100 ppm N from soluble fertilizer injected in irrigation lines supplied by a municipal water source. Number and weight of tomatoes from plants receiving swine effluent were equal to that of plants receiving soluble fertilizer. No differences in fruit quality were evident between treatments. Plant dry weight was also equal for three out of four cultivars. No differences in soil characteristics were detected between treatments after the study. Chemical analysis of the effluent showed a pH of 7.8 and nutrient concentrations of ≈110 ppm NH4-N, 57 ppm P2O5, 150 ppm K2O, and trace amounts of Cu and Zn. Though no differences in yield were detected in this study, the effluent's high pH and high NH4-N content need to be managed more closely for commercial tomato production.
Effect of Compost Applications on the Yield of Several Vegetables in Long-term Organic Farming Experiments Conducted in the Tropics
Authors: Valenzuela H.R. , Crosby C.
Published: February 2019

Experiments conducted over 5 years evaluated the effect of compost applications on the yield of several vegetable crops grown under organic farming conditions in the tropics. The yield of organically grown lettuce, basil, Filipino spinach (Corchorus olitorius L.), and zucchini after application of 20 MT compost/ha per crop was compared to yields obtained with standard synthetic fertilizer applications (150 kg N/ha per crop), and with a combination of several compost: synthetic fertilizer ratios. Treatments consisted of 10 by 1.30-meter raised beds replicated four times. Data collected included soil nutrient analysis prior to planting and after the last harvest, tissue analysis of macro- and micronutrients, canopy dimensions, and yields. The tissue nutrient levels collected from crops receiving composts alone were at or above those levels recommended to achieve commercially acceptable yields. Yields of plants receiving composts alone were comparable to those obtained by plants receiving synthetic fertilizer applications. However, the greatest yields were obtained with 20 MT·ha–1 of compost plus supplemental synthetic N applications, depending on the length of the harvesting period. After 5 years cumulative yields ranged from 110 to 124 MT·ha–1 for vegetables receiving compost plus supplemental N, compared to 75 for controls, and to about 100 MT·ha–1 for treatments receiving either synthetic N or compost applications alone.
Tomato Growth and Yield Response to Cover Crop and Fertilizer Nitrogen
Authors: Whitehead Wayne F. , Singh Bharat P.
Published: February 2019

The goal of this study was to evaluate how tomato yield, vegetative dry matter, leaf area index (LAI), and photosynthesis (Pn) responded to winter cover crop and recommended fertilizer N rates. The following winter/spring fertility treatments were applied using randomized complete block design with four replications: 1) 0 N winter /0 N spring, 2) 0 N winter/90 kg·ha–1 N spring, 3) 0 N winter/180 kg·ha–1 N spring, 4) 0 N winter + abruzi rye/0 N spring, 5) 0 N winter + hairy vetch/0 N spring, and 6) 0 N winter + crimson clover/0 N spring. In Spring 1997, `Mountain Pride' tomatoes were transplanted in all plots. Whole plant dry matter, LAI and Pn were measured at flowering, fruiting and prior to senescence, while seasonal yield was compiled over 6 weeks. Tomatoes preceded by Vetch produced highest plant dry matter (243.0 g/plant) prior to senescence, highest LAI (3.07) at fruiting and highest P (8.98 μmol CO2/m2 per s) during flowering. Total yield were highest (60.9 Mg·ha–1) at 180 kg·ha–1 N and lowest (35.3 Mg·ha–1) in control. Supplemental N from legume and grain cover crops affected plant dry weight, LAI, Pn, and yield comparable to those receiving synthetic N. Results of this study indicate that cover crop treatments were as effective as N fertilizer in supporting tomato yield, vegetative growth, LAI, and photosynthesis.
Evaluation of Summer Cover Crops for Vegetable Production in South Florida
Authors: Bryan Herbert , Li Yuncong
Published: February 2019

Cover crops are used for weed control and to retain nutrients during the heavy summer rains and have become an integral part of vegetable production practices in south Florida. Moreover the use of cover crops will continue to increase as farmers seek to improve soil quality and reduce chemical inputs. A wide variety of plants are used as cover crops in south Florida. Obviously legumes contribute more nitrogen by fixing N compared to nonlegumes such as sorghum–Sudan grass, which is a common cover crop in this area. We have evaluated 10 cover crops, and five of them are legumes. The sunn hemp, Crotalaria juncea L, stands out from other tested cover crops. Sunn hemp produced 8960 kg dry weight per ha and fixed up to 336 kg N/ha. We have strongly recommended sunn hemp as a cover crop for vegetables and tropical fruits in south Florida. A large field demonstration will be conducted in a grower's field in the summer rainy season of 1998.
Yield of `Superior' Potatoes following Nematode-suppressive Cover Crops
Authors: McKeown Alan W. , Potter J.W.
Published: February 2019

`Superior', the common early potato in Ontario, has developed early dying and low yield problems along the Lake Erie Counties. A series of experiments were planted in 1993 to 1996 to evaluate nematode-suppressive cover crops as a means of soil management, improving yield of potatoes, and reduction of plant parasitic nematodes. Sorghum NK557 as a nematode host, reported suppressive species Sordan 79, Trudan 8 sorghum-sudan hybrids, Domo and Cutlass mustard, Forge canola, and `Norlee' flax were compared to either Telone IIB or Vorlex-Cp (225 L/ha) fumigants applied with a deep shank applicator to 30 cm. Fertility and pest management practices followed Ontario recommendations. Northern root lesion nematodes, Pratylenchus pentrans Cobb, populations were monitored prior to planting potatoes, during the season, and after harvest. Fumigation resulted in the highest total yields in all 3 years and marketable yield in 1994 and 1995. There was no difference in marketable yield in 1996. Yield was similar among cover crops treatments. Suppressive crops, while useful in soil management, were not as effective as fumigants.
Metam Sodium Combined with Chloropicrin as an Alternative to Methyl Bromide Fumigation for Tomato
Authors: Locascio S.J. , Dickson D.W.
Published: February 2019

In past work, dichloropropene + 17% Pic (1,3-D + Pic) at 327 L·ha–1 plus pebulate provided good control of nematode, soil fungi, and nutsedge in mulched tomato (Lycopersicon esculentum Mill.) and is considered the best alternative for methyl bromide (MBr) + chloropicrin (Pic), which is scheduled for phase-out in the United States by Jan. 2001. Metam-sodium did not provide acceptable pest control. In the present study, metam-Na (295 L·ha–1 combined with Pic (168 kg·ha–1) + 4.5 kg·ha–1 pebulate, and 1,3-D + 35% Pic at 168 and 225 L·ha–1 + pebulate were compared to MBr-Pic (98-2% at 345 kg·ha–1 and 67-33% at 505 kg·ha–1). Fumigants were injected into the bed except metam-Na and pebulate were surface-applied and incorporated and drip tubing and mulch were applied. Marketable yields with MBr-Pic, 225 L·ha–1 1,3-D + Pic, and metam-Na + Pic were higher than with the check. Yields with metam-Na alone or with additional water before transplanting were similar to the check. Nutsedge was controlled with MBr-Pic and all treatments with pebulate. Nematode root-gall ratings were high on tomato grown without fumigants (8.9 rating on a scale of 0 to 10 with 0 = no galling), low with MBr-Pic (0.33), and intermediate with all other treatments (2.2 to 5.5) except with 168 L·ha–1 1-3-D + Pic (8.3). This study indicates that metam-Na + Pic + pebulate also is a possible alternative to MBr-Pic for tomato.
Assessment of Chemical Induction of Acquired Resistance to Pythium Fruit Rot in Field-grown Cucumber
Authors: Hockin Priscilla M. , Widders Irvin E.
Published: February 2019

Systemic acquired resistance (SAR) is a physiological defense response in plants conferring broad spectrum resistance to pathogens. SAR is inducible through infection by necrotizing pathogens or chemical inducers and involves the systemic activation of defense related genes. The objectives of this study were to evaluate resistance expression to Pythium soft rot in fruit of cucumber in response to foliar applications of 2,6-dichloro isonicotinic acid (INA), benzo(1,2,3)thiadiazole-7-carbothioc acid S-methyl ester (CGA 245704), or beta-amino-butyric acid (bABA). Excised leaves from three cucumber cultivars, Vlaspik, Sumpter and SMR 58, exhibited a resistance response to foliar applications of INA (50 ppm) and CGA 245704 (25 ppm) when challenge inoculated with Colletotrichum lagenarium. However, the reduction in lesion incidence by INA was 99% in Vlaspik and only 11% and 18% in Sumpter and SMR 58, respectively. bABA did not enhance resistance in vegetative tissues. Multiple foliar applications of INA and CGA 245704 prior to fruit set were found to be more effective than a single application. Harvested cucumber fruit, 3.0 to 5.0 cm in diameter, were wounded and challenge inoculated with Pythium sp.; no statistically significant differences in infection were observed between controls and fruit from chemically treated plots. In Vlaspik, however, INA and BTH did reduce the rot infection rate in fruit when foliar applications were made early in plant ontogeny, at the four-leaf stage. In addition, larger more mature fruit (4-5 cm diameter) exhibited slower lesion growth than less developed fruit (>3 cm). It is unclear if these differences were attributable to changes in physiological or anatomical factors. These findings indicate that the level of physiological resistance achievable through chemical induction in cucumber is a function of the specific pathogen and the plant organ being infected, i.e., leaves or fruit.
Two-cluster Tomatoes Require Less Pesticide per 1000 kg of Salable Fruit than Eight-cluster Tomatoes
Authors: Kratky B.A. , Cupples Richard , Maehira Gaillane
Published: February 2019

Tomatoes were grown in plastic-covered rainshelters at a cool, moist 1300 m elevation. Plants were placed in aluminum beverage cans filled with growing medium and immersed in a a 0.6-m wide tank containing 5 cm of non-circulating nutrient solution. Tomatoes were pruned such that only two, four, or eight clusters were harvested. Two-cluster `Vendor' tomatoes yielded 49% and 73% more salable tomatoes per day than eight-cluster tomatoes in two experiments, respectively. Two-cluster `Lenor' tomatoes yielded 47% and 92% more salable tomatoes per day than eight-cluster tomatoes in two experiments, respectively. Two-cluster tomatoes required 347 g of pesticide to produce 1000 kg of salable fruit compared to 708 g pesticide for eight-cluster tomatoes in the first experiment. Fungal pressure increased in the second tomato experiment such that the two-cluster tomatoes required 1112 g of pesticide to produce 1000 kg of salable fruit, whereas the eight-cluster tomatoes required 2075 g of pesticide. Most of the pesticides applied were fungicides.
The Effects of American Black Nightshade (Solanum americanum) Interference in Bell Pepper (Capsicum annuum)
Authors: Roos Debbie L. , Stall W.M. , Shilling D.G. , Kostewicz S.R. , Swisher M.E.
Published: February 2019

Information about the effects of weed interference on crop yields can help growers make appropriate management decisions. Such information is particularly useful in horticultural crops such as pepper, where the number of registered herbicides is limited. Bell pepper is the second most-valuable vegetable crop grown in Florida, and American black nightshade (Solanum americanum) is one of the primary weeds in Florida pepper production. Additive experiments were conducted in 1997 in Florida to determine the effects of American black nightshade interference on bell pepper yield. One additive experiment was conducted in Gainesville, Fla., in the spring and two additive studies were conducted in the fall in Gainesville and Live Oak, Fla. A randomized complete-block design with four replications was used. Double rows of `Capistrano' peppers were transplanted into white polyethylene mulched beds with 1.22-m centers. Peppers were planted at an in-row spacing of 0.3 m. Weeds were propagated in the greenhouse in polystyrene flats and transplanted at the two-leaf stage simultaneously with the peppers. Overhead irrigation was used and monitored with tensiometers. Fertilizers and pesticides were applied based on Extension recommendations. Weed densities in the spring trial were 0, 2, 4, 8, 12, 16, and 20 plants/m2. Weed densities of 0, 0.5, 1, 1.5, 2, 3, 4, and 8 plants/m2 were planted in the fall. Crop and weed heights were recorded weekly, and fruit number, grade, and weights were recorded at each harvest. Crop and weed dry weights were obtained at final harvest. Data were subjected to analysis of variance and regression. There was an interaction by season, but there was not an interaction by location for the fall season; therefore, the fall data were combined. In all trials, S. americanum had a significant effect of bell pepper fruit yield. In the spring, the biological threshold of weed interference occurred at a density of four S. americanum/m2, but only caused a 50% yield loss. In the spring, the critical density causing 20% yield loss was calculated from the regression model to occur at 0.36 S. americanum/m2. A calculated density of 0.58 S. americanum/m2 caused 20% yield loss in the fall. Plant height and dry weight data indicated that the pepper initially grew more quickly in the fall than in the spring.
Endocarp Structural Components of Insect Resistance in Almond
Authors: Freeman M. , Walters C. , Thorpe M.A. , Gradziel T.
Published: February 2019

Almond, as with other stone fruit, possesses a highly lignified endocarp or shell. The dominant hard-shelled trait (D-) is positively associated with greater resistant to insect infestation than nuts expressing the paper-shelled (dd) trait. Hard-shelled genotypes have undesirable effects, including a lower kernel meat-to-nut crack-out ratio, greater kernel damage during mechanical shelling, and a reduction in plant energy available to kernel development. Histogenic analysis shows that the almond endocarp, unlike peach, has a tri-partite structure. Insect feeding studies have subsequently demonstrated that the inner endocarp layer, which is similar in both hard and paper-shelled types, is the most important structural barrier to insect infestation. Shell-seal integrity and X-ray studies have confirmed that discontinuities at the inner endocarp suture seal are the primary, though not the sole site of entry for insect pests. Paper-shelled almond selections with highly lignified and well-sealed inner endocarps show resistance levels comparable to hard shelled types but with crack-out ratios 30% to 40% higher. Pseudo-paper-shelled types have also been selected, in which a highly lignified outer endocarp is formed, but is retained by the fruit hull at dehiscence. An understanding of endocarp morphology and development is thus important in breeding for insect resistance as well as the commercial utilization of both kernel and hull.
Breeding and Improvement of Seguin Chestnut (Castanea segunii)
Authors: Norton J.D. , Huang Hongwen
Published: February 2019

The seguin chestnut, commonly called Maoli in China, is one of the three chestnut species (C. mollissima, C. seguinii, and C. henryi) native to southeastern and central China. Seguine is a valuable germplasm resource for horticultural traits such as precocity, everbearing, high yield, blight resistance, and dwarfism. A recurrent selection breeding program was initiated in 1989. Since seedlings flowered as early as 3 weeks, selections were made annually for seven generations. Improvement in precocity, everbearing, yield, quality, blight resistance, and dwarfism is sought. The everbearing and high-yielding plants should provide an abundant source of food for wildlife on a continuing yearly basis. Incorporation of the precocious and dwarf traits into commercial chestnut species can enhance the development of high-density chestnut production.
Establishment of a Non-dormant Blueberry (Vaccinium Corymbosum Hybrid) Production System in a Warm Winter Climate
Authors: Darnell Rebecca L. , Williamson J.G. , Obreza T.A.
Published: February 2019

A high-density planting of three southern highbush cultivars was established in 1994 in southwest Florida to test the feasibility of a non-dormant blueberry production system. A non-dormant system involves continuous application of nitrogen throughout fall and winter, which enables the plants to avoid the normal dormancy cycle and the concomitant chilling requirement. Three nitrogen fertilizer rates and two organic soil amendments (muncipal solid waste compost and acidic peat) were evaluated for effects on maintaining plant growth in this system. In general, increasing N rates from 84 to 252 kg·ha–1 increased plant canopy volume, leaf retention, and rate of new vegetative budbreak. Plant height and volume were consistently greater for plants grown in the compost compared to the peat amendment, but there were no differences in leaf retention or vegetative budbreak between the two soil amendments. Flower bud density and fruit yield were increased in plants grown in the compost compared to the peat, while N rate had no effect on either. Plants in this non-dormant system have shown no deleterious growth effects, suggesting that establishing a blueberry planting in a warm winter climate is feasible under the described conditions.
Researching Alternative Cash Crops for Small Scale Farmers in Southern Ohio
Authors: Bergefurd Brad , Gao Gary
Published: February 2019

Speciality crops are great alternative cash crops for small scale farmers. Small scale farmers are constantly searching for viable economic crops to grow. We have been conducting applied research on the production and marketing of culinary herbs, oriental vegetables, colored peppers, and muskmelons to name a few. These crops show excellent potential for southern Ohio. Field demonstration, seminars, and surveys were used to gather and disseminate information on these speciality crops. More than 230 people attended our seminars on alternative cash crops. More than 150 people attended our field days. In addition, we had identified many chefs that are willing to purchase from local speciality crop growers. It will be a win-win situation for both chefs and growers. Growers will be able to maximize their profitability while chefs will receive fresh and unique produce. As a result of our research, we were able to show small scale growers what they can grow successfully and how they can market their crops for most profit. These applied research projects received a combined funding of $10000.00 from OSU Extension-Innovative Grant program. These projects are a great way to establish credibility among clients. We would also like to demonstrate how other extension agents can help their clients. A lecture utilizing slides and overhead transparencies will be the format of the seminar.
Extending Biologically Integrated Farming Practices within the San Joaquin Valley's West Side
Authors: Mitchell J.P. , Goodell P.B. , Coviello R.L. , Prather T.S. , May D.M. , Hartz T.K. , Pettygrove G.S. , Hembree K.J. , Munk D.S. , O`Neill T. , Diener J.
Published: February 2019

The West Side On-Farm Demonstration Project is a large-scale extension program consisting of farmers, researchers, extension advisors from the Univ. of California, and other private and public agency consultants who are evaluating biologically integrated soil-building and pest management practices within a participatory and on-farm demonstration context. Modeled after the Biologically Integrated Orchard Systems (BIOS) Projects that were originally sponsored by the Community Alliance with Family Farmers, the goals of this project are to facilitate information exchange among West Side farmers, consultants and researchers on soil-building practices and options for reduced reliance on agrichemical inputs, to monitor and evaluate on-farm demonstrations of soil-building practices, including cover cropping and organic soil amendments, and to determine the extent to which IPM practices are utilized in row crops on the West Side and identify constraints preventing further adoption of biologially intensive pest management practices. The Project has generated several adjunct research activities and considerable regional attention. A summary of ongoing impact assessment efforts will be presented.
U.S.–Hungarian Horticultural Research Program for Stress-tolerant Ornamental Plants
Authors: Szendrak Erika , Read Paul E. , Schmidt Gabor , Steinegger Donald H. , Morrissey Todd M.
Published: February 2019

Pollution has become one of the most important problems in urban and industrial environments and plants are considered to be one of the best means for diminishing its harmful effects. Installation of landscape plants is probably the cheapest and one of the most effective ways to reduce the adverse effects of polluted or stressful environments. Resistance or tolerance of various plant species against environmental stresses (e.g., pollution, drought, high salt content and poor aeration of soil, human damage) varies dramatically with type of plant species and cultivar. Nebraska and Hungary have many similarities in climate and geographical characteristics and researchers have accumulated considerable results in the field of plant environmental stress and pollution tolerance. However, time and history have prevented cooperative work until recently. Excellent connection and cooperation with the Univ. of Horticulture and Food, Budapest and several Hungarian nurseries was established by the Dept. of Horticulture, Univ. of Nebraska–Lincoln and the Nebraska Statewide Arboretum,which was an optimal foundation for this research project. Our overall goal was to mutually utilize the rich genetic materials and experience which have accumulated in these two regions during the past 5 decades. This continues to be accomplished by a systematic germplasm-exchange program and testing pollution- and stress-tolerant tree, shrub and herbaceous perennial cultivars, along with investigations of the physiological mechanisms of their stress reactions and biotechnological methods for mass-propagation. The presentation will highlight the main results of this several years long joint program.
Characterization of α-Farnesene Synthase from `Delicious' Apples
Authors: Rupasinghe H.P.V. , Paliyath G. , Murr D.P.
Published: February 2019

α-Farnesene metabolism is associated with the occurrence of superficial scald in pome fruits. Trans,trans-α-farnesene synthase, which catalyzes the terminal step of α-farnesene biosynthesis viz. conversion of farnesyl pyrophosphate to α-farnesene, has been characterized in the extract from skin tissues of `Delicious' apples (Malus domestica Borkh.). The total and specific activities of the enzyme were the highest in the cytosolic fraction when compared to that in membrane fractions. The enzyme possessed a pH optimum of 5.6 and required a divalent metal ion (Mg+2 and Mn+2 were preferred). The activity was highest between 10 and 20 °C, although 50 % of the activity was still retained at 0 °C. The presence of thiol reagents, pyridine dinucleotide effectors, anaerobic conditions or antioxidants did not significantly affect enzyme activity. α-Farnesene synthase activity was similar in the extract of skin tissue from scald-developing and non-scald-developing apples. The enzyme activity was not correlated to the inherent nature of scald-susceptibility or resistance in eight different apple cultivars tested.
Developing a Quantitative Method to Evaluate Peach and Nectarine Flesh Mealiness
Authors: Crisosto Carlos H. , Ju Zhiguo , Garner David
Published: February 2019

A quantitative method to measure peach and nectarine flesh mealiness was developed. To measure “free water”, ≈30 to 40 g of fruit tissue was wrapped with four layers of cheesecloth (20 × 20 cm) and subjected to 17.4 N of force using a prototype press. After the fruit tissue was pressed for 1 min, the force was released. Pressing of the fruit tissue was repeated four times, after which no further juice or pectins were released. The juice was collected and centrifuged at 6,000 xg for 10 min. The residue was discarded and the supernatant was weighed and used to represent “free water” from the tissue. The percentage of “free water” had a higher correlation to mealiness perception by a trained taste panel and visual observation than the percentage of juice. This “free water” measurement is an objective and reliable method to evaluate genetic material, physiological changes during storage, and any treatment's effect on mealiness.
Ploidy of Regenerated Broccoli Derived from Microspore Culture Versus Anther Culture
Authors: Wang Min , Farnham Mark W.
Published: February 2019

Anther and microspore culture are commonly utilized to produce doubled-haploid (diploid), homozygous lines in broccoli (Brassica oleracea L. Italica Group). It is well-documented that doubled-haploid regenerants are produced by means of polyploidization during anther culture. However, polyploidization may not occur at all, or it may involve a tripling or quadrupling of the chromosome complement. As a consequence, regenerated populations from anther culture contain diploids, but also haploids, triploids, and tetraploids. Microspore culture represents a simpler and more direct method for producing doubled-haploids. Although a similar mix of ploidy types is likely to be observed among regenerants derived from microspore culture, the actual ploidy levels of such regenerants have not been documented for broccoli. Thus, the objectives of this study were to compare ploidy levels of regenerants developed using both anther and microspore culture in broccoli, and to examine phenotypic variation in ploidy makeup of populations developed from both anther and microspore culture using different F1 hybrids. Broccoli regenerants were derived simultaneously from both anther and microspore cultures using the same four F1 hybrids, including Everest, Patriot, Greenbelt and Major. Ploidy level was determined by flow cytometry. A majority of regenerants derived from both anther and microspore culture, were determined to be diploids or tetraploids. Significant differences in ploidy makeup of populations were observed among hybrid varieties for both culture techniques. Regardless of the culture method used, `Everest' produced a greater percentage of diploids and a lower percentage of tetraploids than `Patriot' did. Haploids were observed more frequently from microspore culture than from anther culture when `Everest' and `Major' served as parents.
Field Screening for Onion White Rot Resistance
Authors: Voss Ronald , Brittan Kent , Phillips Herb , Kirby Donald , Davis W.Michael , Gabelman Warren , Goldman Irwin , Havey Michael
Published: February 2019

Onion white rot disease (Sclerotium cepivorum) is a serious production problem throughout the world. Very low pathogen level in the soil can cause significant loss. Generic integrated pest management programs include clean seed, site selection, sanitation, crop rotation, biological and chemical controls, crop resistance to the pest, and other components. Onion white rot disease management currently does not have crop resistance as a component. The lack of resistant germplasm and/or the inability to identify and screen potentially resistant germplasm are primary reasons. Research was conducted to determine if field screening for resistance is feasible, to define field screening methodology, and to identify and/or quantify resistance. Disease incidence was inconsistent from year to year. In some years, disease expression was high; in others, disease was low. Uniform pathogen level and disease expression throughout the experimental field were required for successful screening. Results provide evidence that “resistant” or “tolerant” germplasm does exist, and that disease “resistance”, “tolerance”, or “susceptibility” can vary from slight to strong, suggesting multigenic involvement. “Resistance”/”tolerance” was identified in long-day yellow hybrids and inbreds. `Southport White Globe' selections and derivatives had much higher disease susceptibility than yellow or brown skin lines screened.
Effect of In-row Plant Spacing on Yield of `Beauregard' Sweetpotato
Authors: Walters S. Alan , Schultheis Jonathan R.
Published: February 2019

Several in-row plant spacings (15, 23, 31, and 38 cm) of `Beauregard' sweetpotato [Ipomoea batatas (L) Lam.] were evaluated to determine which spacing produced higher yields under North Carolina growing conditions.The 15 cm spacing (the closest spacing evaluated) gave the highest root yields.With closer plant spacings, the yields of No. 1 grade roots increased compared to wider plant spacings.The No. 1 grade is the most desired and gives the grower the greatest monetary return.Jumbo grade root production increased with wider plant spacings due to less plant-to-plant competition compared to those at closer spacings.In most cases, the widest spacing tested for `Beauregard' (38 cm) produced lower yields (except for jumbo grade yields) to the other spacings tested.
Strawberry Transplant Propagation in Elevated Horizontal Troughs
Authors: Bish Eric B.
Published: February 2019

Commercial strawberry cultivars are vegetatively propagated in field nurseries. Mother plants produce daughter plants on stolons in response to long photoperiods and high temperatures. The daughter plants are primarily removed from the field as a bare-root transplant. These bare-root transplants can be extremely stressed in this digging process, resulting in plant variability and pathogen infestation. A strawberry transplant production system has been developed that uses micropropagated disease free mother plants in elevated horizontal culture. The mother plants are grown in suspended plastic troughs (10-cm width by 10-cm depth) with a soilless medium consisting of vermiculite and perlite. The mother plants are subfertigated via drip tubing to avoid leaf wetness. Stolons produced by the mother plants hang over the trough and continue to grow down toward the ground. The stolon tips, are harvested and rooted in plug trays. This study compared proliferation rates of several strawberry cultivars. The benefits of the elevated system were: disease-free plants, high-density daughter plant production, all the runners could be removed at one time and separated for propagation, and the daughter plants had active root tips that established quickly.
Sepal Color Change Relates to Fruit Quality, Firmness, and Detachment Force in Erect and Semi-erect Thornless Blackberry Cultivars
Authors: Stiles Herbert D. , Tilson W. Malcolm
Published: February 2019

Black coloration occurs before the inception of horticultural maturity, so other cues (sheen, drupelet shapes, drupelet sizes, and fruit detachment force) have been employed as indicators of physiological and horticultural maturity among erect and semi-erect thornless blackberry cultivars. A more distinct visual cue might, however, allow reductions in the variability of quality, firmness, and shelflife among manually harvested berries. Such a maturity indicator would allow researchers to select more-uniform materials for genetic and physiologic studies of blackberry fruit ripening and quality development. Our 1996 and 1997 data confirm earlier observations of sepal color relationships to fruit quality attributes (soluble solids, pH, titratable acidity, and sugar/acid ratio) among semi-erect cultivars, and they show that such relationships exist among erect cultivars. These data also demonstrate relationships among sepal color, fruit detachment force, and berry firmness in both phenotypes.
The Effect of Water Shortage on Potted Peach Trees in Relation to Ecophysiological Parameters and Infra-red Thermometry
Authors: Giuliani Rita , Flore James A.
Published: February 2019

Potted peach trees grown outdoors during the 1997 season were subjected to drought and subsequent rewatering to evaluate their dynamic response to soil water content. The investigation was primarily focused on the early detection of plant water stress to prevent negative effects on the growth. Leaf chlorophyll fluorescence and canopy temperature estimates (by infra-red thermometry) were conducted. Drought effect on physiological processes were detected through by estimates of canopy development rate, leaf gas-exchange measurements; while leaf water potential was measured to characterize plant water status. A decrease in the canopy's development rate was found 1 week after irrigation was stopped, which also coincided with a more-negative leaf water potential, whereas a decrease of the gas-exchange activities occurred several days later. No significant differences between the stressed and control plants were recorded by the chlorophyll fluorescence parameters (Fo, Fm, Fv and the ratio Fv/Fm), whereas the infra-red estimates of canopy temperature detected a slight increase of the canopy surface temperature (connected to the change of leaf energy balance and in relation to partial stomatal closure) on the non-irrigated plants 1 week after the beginning of the trial. The use of infra-red thermometry for early detection of water shortage is discussed.
Thermal Blast Peeling of Sweetpotatoes
Authors: Smith D.A. , Harris H.
Published: February 2019

Thermal blast peeling is a process whereby peels and blemishes are efficiently removed from produce by holding the produce for a brief period in a heated, closed vessel filled with superheated steam under elevated pressure while supplemental radiant heat is supplied by the vessel wall. This intense, dry heat superheats a film of moisture immediately underlying the peel tissue. The pressure within the vessel is then instantaneously reduced by opening the vessel. Steam within the vessel expands blowing the produce free of the vessel and simultaneously the superheated water in and immediately underlying the peel flashes to steam thus cleanly exploding the peel tissues from the produce. Different size grades and cultivars of sweetpotatoes were peeled by the Thermal blast process, hot caustic immersion, or by high-pressure saturated steam. Thermal blast-peeled sweetpotatoes had higher product recoveries, less heat penetration into the tissue, and better color than caustic or saturated steam-peeled potatoes.
Apoplastic pH and Mineral Composition during Ripening of Tomato Pericarp
Authors: Almeida Domingos P.F. , Huber Donald J.
Published: February 2019

Ionic conditions and pH affect the catalytic activity of polygalacturonase and other cell wall enzymes, as well as non-enzymic pectin solubilization. Despite its potential role in regulating fruit ripening, apoplastic pH and mineral composition in ripening fruit are poorly documented. A pressure-extracted fluid was obtained from tomato pericarp, using a constant pressure of≈0.6–0.7 MPa for immature and mature-green fruit and 0.3–0.5 MPa for pink and red fruit. The osmolality of the pressure-extracted fluid ranged from 66 to 138 mmol·kg–1 compared with 268 to 293 mmol·kg–1 for the bulk pericarp homogenate, which attests to the putative apoplastic origin of the fluid. The pH of the apoplastic fluid was 6.7 at the immature and mature-green stages and dropped to 4.4 by the ripe stage, whereas bulk pericarp pH dropped from 4.6 to 4.3. [K+] in the apoplast increased from 13.2 mM at the mature-green stage to 37.3 mM at the ripe stage, whereas the bulk tissue [K+] ranged from 44 to 49 mM without relation with ripening stage. [Mg2+] declined from 11.9 mM in immature fruit to 8.7 mM in mature-green fruit and then increased to 12.9 mM in ripe fruit. [P] increased from 1.5 to 4.8 mM during ripening, and [Cl–] remained around 3.8 to 4.0 mM until the pink stage, increasing to 6.5 mM at the ripe stage. [Na+] remained constant at 6.2 to 6.5 mM, whereas [Ca2+] ranged from 3.5 to 4.9 with no consistent relationship with ripening stage. The changes in pH and ionic composition of the pericarp apoplast may affect the binding and catalysis of cell wall hydrolases and physical interactions between structural polysaccharides.
Drip Irrigation and Stand Establishment Affect Yield and Quality of Cantaloupe
Authors: Leskovar D.I. , Ward J.C. , Sprague R.W. , Meiri A.
Published: February 2019

Water pumping restrictions of high-quality irrigation water from underground aquifers is affecting vegetable production in Southwest Texas. There is a need to develop efficient deficit-irrigation strategies to minimize irrigation inputs and maintain crop profitability. Our objective was to determine how growth, yield, and quality of cantaloupe (Cucumis melo L. cv. `Caravelle') are affected by irrigation systems with varying input levels, including drip depth position and polyethylene mulch. Stand establishment systems used were containerized transplants and direct seeding. Field experiments were conducted on a Uvalde silty clay loam soil. Marketable yields increased in the order of pre-irrigation followed by: dry-land conditions, furrow/no-mulch, furrow/mulch, drip-surface (0 cm depth)/mulch, drip-subsurface (10-cm depth)/mulch, and drip-subsurface (30 cm depth)/mulch. Pooled across all drip depth treatments, plants on drip had higher water use efficiency than plants on furrow/no-mulch or furrow/mulch systems. Transplants with drip-surface produced 75% higher total and fruit size No. 9 yields than drip-subsurface (10- or 30-cm depth) during the first harvest, but total yields were unaffected by drip tape position. About similar trends were measured in a subsequent study except for a significant irrigation system (stand establishment interaction for yield. Total yields were highest for transplants on drip-subsurface (10-cm depth) and direct seeded plants on drip-subsurface (10 and 30 cm depth) with mulch.