bluuebunny/crossref_metadata_2025 huggingface dataset:
Fruit Drop in `Empire' Apple by Position within the Cluster in Unthinned Trees vs. Trees Thinned to Single-fruited Clusters
Authors: Goffinet Martin C. , Lakso Alan N. , Robinson Terence L.
Published: February 2019

For 4 years, six-flowered clusters on 20, unthinned, open-pollinated `Empire'/MM106 trees were labeled at bloom and fruit drop monitored at the king (K) and lateral positions L1 (basal) to L5 (distal) (100 to 120 clusters/year). Depending on year, fruit dropped in 1, 2, or 3 major periods by 8 weeks postbloom (PB), with total percent dropped between 65% and 75%. K fruit dropped least, L4 and L5 most. Trends were that K fruit at October harvest were largest and heaviest (significantly so in some years) and L5 fruit smallest. In nine trees, hand-thinned to single-fruited spurs at 12 days PB, where the fruit at the retained position was known, there was no statistical difference in fruit weight, fruit size, or seed count between cluster positions at final harvest, although L5 fruit tended to be smallest. Numbers of spurs labeled varied from 45 to 72. Percent fruit retained at each position at October harvest was K = 89%, L1 or L2 = 87%, L3 = 83%, L4 = 83%, and L5 = 85%. Presumably, in unthinned trees the limited resources are preferentially taken by the K fruit, which especially seems to reduce set and size of its nearest lateral fruit. However, in thinned trees under lighter cropping stresses, a fruit retained at any of the positions within a cluster has a similar potential for achieving the size and weight typically seen in king fruit.
Fruiting of High-density Apple Orchards on Clonal Rootstocks
Authors: Devyatov A.S.
Published: February 2019

Orchard densities from 833 to 2500 trees/ha were studied on sod-podzolic soil (annual precipitation 550 mm). An orchard was planted in Spring 1990 and 1991 using 2-year-old nursery trees grown in film containers. The interval between trees in the row was 1 to 1.5 to 2 to 2.5 and 3 m. The trees were grafted on dwarf rootstock (62-396) and semi-dwarf (54-118). The commercial fruiting of `Tellisaare' began the third year after planting, `Antey' the fourth, and Spartan at fifth. The initial yield of `Antey in the most dense treatment was 14.5 t·ha–1, `Tellisaare' was 15 to 22 t·ha–1, according to rootstocks. Average yield of `Antey' on 62-396 for 1992–95 at the orchard density of 2500 trees/ha was 10 t·ha–1·year–1 and on rootstock of 54-118 it was 21 t·ha–1. However, yield of `Tellisaare' 54-118 for 1992–1995 was 13 to 15 t·ha–1 in all treatment of orchard density from 1666 to 833 trees/ha. The annual yield of this cultivar grafted on rootstock 54-118 at a tree density of 2500 plants/ha increased to 18.3 t·ha–1.
Design of Digitally Controlled Evaporative Cooling System for Apple Trees
Authors: Rogoyski Matthew , Gaus Alvan , Broner Israel , Mourey Thomas
Published: February 2019

An evaporative cooling system for apple trees was implemented. The system is automated to conserve irrigation water. The automation is based on the digital, integrated thermometer and thermostat chip embedded in the artificial fruit. The thermometer–thermostat chip drives a solid state relay. The relay controls a solenoid operated valve. A typical duty cycle consisted of 1 to 2 minutes of wetting (water on) to 4 to 10 minutes drying (water off). Differences in the length of duty cycles between individual chips were observed. The reliability of the system was adequate. The waterproofing of the system's electrical components was its weak point. Irrigation water deposits accumulated on the apple fruit surface during the growing season were readily removable with a simulated brush technique.
Generative Patterns: A Potential Role in the Management of Complexity in Production Agriculture
Authors: Rogoyski Matthew , Gaus Alvan , Mourey Thomas , Broner Israel , Lakey Jeffrey
Published: February 2019

A novel way to capture long-standing agricultural experience and knowledge in the form of generative patterns is proposed. These patterns can be thought of as solution paradigm where the solutions are the essence of the patterns. A pattern does not provide a concrete solution to a problem but can be considered of as a worldview of the problem or a solution space. A pattern initiates and generates human cognitive behaviors that indirectly facilitate, elucidate, and solve a problem. An application of generative patterns to production agriculture is proposed. An individual pattern, as described here, associates a problem, its context, the forces affecting it, and a solution. A pattern recurring in production agriculture, the socalled uniformity pattern, is presented, and its horticultural example is discussed.
Tree Size of Ten Asian Pear Cultivars on Five Old Home × Farmingdale Rootstocks
Authors: Larsen Fenton E , Higgins Stewart S.
Published: February 2019

The influence of five Old Home × Farmingdale (OHF) rootstocks on tree size with 10 Asian pear scion cultivars was examined after 10 years in an experimental orchard in central Washington state. The effect of rootstock on tree size varied among scion cultivars. Within `Chojuro', `Hosui', `Niitaka', and `Seigyoku', trunk cross-sectional areas were similar regardless of rootstock. Within `Li', OHF 333 produced larger trees than OHF 282 and OHF 217. `Okusankichi' trees, which were generally the same size as `Hosui', were significantly larger on OHF 217 and OHF 97 than on OHF 333. `Kikusui' trees, which were generally similar in size to `Niitaka' and `Seigyoku', were larger on OHF 217, OHF 97, and OHF 282 than on OHF 333. `20th Century', which was similar in size to `Chojuro' and `Shinseiki', appeared to be the cultivar most sensitive to rootstock. `20th Century'/OHF 217 were significantly larger than trees on OHF 97 and OHF 282, which were larger than trees on OHF 51. `Shinseiki'/OHF 97 were larger than trees on OHF 333. The smallest trees were `Shinko', with trees on OHF 217, OHF 97, OHF 333, and OHF 51 all being larger than trees on OHF 282. Contrary to research with some European pear scions, consistent trends did not emerge from this research that would allow a general prediction of the relative influence of these five OHF clonal rootstocks on Asian pear tree size.
Orchard Performance of Seedling and Clonal Rootstocks for Peach on a Severe Peach Tree Short-life Site
Authors: Beckman T.G. , Reighard G.L. , Nyczepir A.P. , Okie W.R.
Published: February 2019

Thirteen rootstocks grafted with Redhaven peach were established on a severe peach tree short-life (PTSL) site in central Georgia. Most rootstocks tested were peach seedling types: Lovell, Nemaguard, Guardian (BY520-9), BY520-8, Boone County, Bailey and two `Tennessee Natural' selections. A seedling plum rootstock, St. Julian, was also used. Clonal type rootstocks included a peach × almond hybrid, GF677; plum, GF43 and Damas 1869; and a plum hybrid, GF655-2. Trees on Guardian displayed the best survival with only 20% mortality due to PTSL, through 7 years. In contrast, 40% of trees on Lovell succumbed to PTSL. Currently, Lovell is the recommended rootstock for PTSL-prone sites. Other rootstocks ranged from 50% to 100% mortality due to PTSL. Trees on Guardian displayed significantly higher vigor through the first 4 years following planting compared to trees on Lovell. Furthermore, trees on Guardian produced significantly greater yields than those on Lovell, in all but 1 year. Rootstock effects on tree survival, vigor, bloom and harvest dates, fruit yield and size, and suckering will be discussed.
Promoting Lateral Branching on Young Sweet Cherry Trees
Authors: Guimond Charlotte M. , Andrews Preston K. , Lang Gregory A.
Published: February 2019

Young sweet cherry (Prunus avium) trees are typically upright, vegetatively vigorous, and nonprecocious, taking 5 to 6 years to come into production. To produce fruit in high-density orchards by year 3 or 4, development of lateral shoots for potential fruiting is critical in year 2 or 3. An experiment was designed to promote lateral branching on 2-year-old trees. The experiment was conducted in a commercial orchard in Roosevelt, Wash., with `Bing' and `Van' on the vigorous rootstocks Mazzard and Colt. The trees were planted at 415 trees per acre with three scaffolds trained into a “V” canopy design. The experimental variables were treatments with and without Promalin (1.8% BAP plus 1.8% GA4+7), applied at a ratio of 1:3 in latex paint at green tip stage; superimposed on these treatments were either heading cuts of each scaffold to 2 m long (or tipping the scaffold if it was <2 m), removing four to five buds subtending the terminal bud, a combination of heading and bud removal, or controls. On trees that were not treated with Promalin, three additional treatments included either removing subtending buds at budbreak, or removing buds at multiple locations along the scaffold at green tip or at budbreak. New lateral shoots were counted 4 weeks after budbreak, and the quality of the shoots (shoot diameter and angle of emergence) was measured at the time of summer pruning. Interactions between Promalin, bud manipulation, and pruning will be discussed in relation to development of canopy structure.
Potato Production in Wide Beds Compared to Conventional Rows
Authors: Mundy Charlotte , Creamer Nancy G. , Frampton Jane
Published: February 2019

Regional growers have expressed an interest in the feasibility of producing potatoes on wide beds. Using wide beds decreases compaction and may increase water available to the crop due to the elimination of postplanting cultivation, or hilling, required in conventional rows. The middle row of wide beds may have cooler soil temperatures than the other rows in the bed. In addition, wide beds allowed for a planting density 1.5-times greater than conventional rows, which could significantly increase yields. Potatoes, `Atlantic', were planted mid-March into conventional rows on 38-inch centers and 6-foot 4-inch-wide beds, each bed with three rows. Plots were 50 feet long. Initial soil moisture contents in the middle of the bed, the outer rows of the bed and the conventional rows were not significantly different. Initial soil temperature data suggests that fluctuations in temperature are greatest in the conventional rows and least in the middle row of the wide beds. Soil temperature and soil moisture are reported. Marketable yields from wide beds are compared to marketable yields from conventional rows. Influence on potato size distribution and quality factors also are reported.
The Effect of Ornamental Grasses Used as a Windscreen on Chili Pepper Yield
Authors: McKenney C.B. , Tyler Helen
Published: February 2019

Chili pepper yield may be hampered by wind-blown sand and high evaporative demand common in semiarid regions. Initial establishment of the crop is of great importance to overall yield. Due to their reduced size, ornamental grasses could serve as windscreens in urban gardens. In this project, seven species of ornamental grasses (Cortaderia selloana `Pumila', Erianthus ravennae, Miscanthus sinensis `Autumn Light', Miscanthus sinensis `Gracillimus', Miscanthus sinensis `Silberfeder', Miscanthus sinensis `Variegatus', Miscanthus sinensis `Zebrinus', and Pennisetum setaceum `Rubrum') were used as aesthetic windscreens. Capsicum annuum `NuMex Big Jim' chili pepper yield was significantly affected by species of grass in the windscreen. The number of peppers per plant was also significantly affected by species; however, the weight of each pepper was not significantly impacted. Effect of species of ornamental grass in the windscreen may be due to differences in wind resistance, moisture competition, or shading between species. The durability, increase in yield, and aesthetic nature of the ornamental grasses used as windscreens provides several reasons to take advantage of these perennial grasses for an aesthetic form of garden protection.
Properties and Use of MEISTER (Polyolefin-coated Urea) with Accurately Controlled Availability in Japan
Authors: Fujita T. , Kosuge K. , Miyoshi S. , Shoji S.
Published: February 2019

Polyolefin-coated urea commercially called “MEISTER” was invented by T. Fujita and his co-workers. It shows primarily temperature-dependent dissolution and is divided into two groups of dissolution: ordinary (linear) and delayed (sigmoid). The dissolution of MEISTER in the soil is predicted easily with reasonable accuracy by a portable computer using temperature data. Thus, we can select kinds of MEISTER that can release N meeting the plant demand. It has been common knowledge that polymer-coated materials are used mainly on lawns, professional turf, and container-grown ornamental and horticultural plants and to a limited extent, in vegetable production. However, MEISTER is applied not only to high-value crops but also to low-value crops in Japan because this fertilizer can contribute to innovative fertilizer placement and farming systems (described later in this abstract), thereby the total farming cost can be notably reduced. Innovative fertilizer applications; co-situs placement and single basal application Innovative farming systems; paddy rice 1) no-till rice culture by direct-seeding and a single basal co-situs application and 2) no-till transplanting rice culture by single basal fertilization; and upland and horticultural crops 1) multi-cropping by a single basal fertilization and 2) no-till cropping by a single basal co-situs application.
Prospects for Mechanical Harvest of Zucchini Squash
Authors: Wyatt Jim E.
Published: February 2019

Removing a portion of the foliage of zucchini squash without reducing yield would increase the efficiency of mechanical harvest since less plant material would be passed through the harvester. Pruning 50% of the leaves and petioles at either first or second harvest had no effect on third harvest fruit yield. Primary or secondary fruit growth rates were not affected by leaf removal. Presence of a primary fruit reduced the number of secondary fruit developing to marketable size but the rate of secondary fruit development was similar on plants with one, two, or three fruit. The maximum fruit to develop at one time in this planting was two per plant. Following one or two hand-harvests of zucchini squash, mechanical harvest efficiency will be increased after removal of 50% of the leaves and maturation of two marketable fruit per plant.
Cover Crop and Tillage Effects on Production and Nitrogen Nutrition of Sweet Corn
Authors: Cline Gary R. , Silvernail Anthony F.
Published: February 2019

A split-plot factorial experiment examined effects of tillage and winter cover crops on sweet corn. Main plots received tillage or no tillage. Cover crops consisted of hairy vetch, winter rye, or a mix, and N treatments consisted of plus or minus N fertilization. No significant effects of tillage on sweet corn yields were detected. Following corn not receiving inorganic N, vetch produced cover crop total N yields of 130 kg·ha–1 that were over three-times greater than those obtained with rye. Following rye winter covercrops, addition of ammonium nitrate to corn significantly (P < 0.05) increased corn yields and foliar N concentrations compared to treatments not receiving N. However, following vetch, corn yields and foliar N concentrations obtained without N fertilization equaled those obtained with N fertilization following rye or vetch. Available soil N was significantly (P < 0.05) greater following vetch compared to rye for ≈9 weeks after corn planting and peaked ≈4 weeks after planting. It was concluded that no-tillage sweet corn was successful and N fixed by vetch was able to sustain sweet corn production.
Effects of Repeated Application of Four Rates of Two Composts Varying in Carbon: Nitrogen Ratio on Soil Nitrogen and Leaf Lettuce Yield
Authors: Gaskell M.L.
Published: February 2019

The effects of repeated application of two composts differing in carbon: nitrogen (C: N) ratio on soil NO3-N, soil NH4-N, and leaf lettuce yield was studied over three sequential crop cycles from 1995 to 1996. One compost type (HiCN) was prepared primarily from yard wastes and had a C: N ratio of 29 to 32:1 The other compost (LoCN) was a compost composed of a mixture of crude materials including yard wastes, feedlot manures, and vegetable trimmings and had a C: N ratio of 10 to 12:1. Before transplanting leaf lettuce, both composts were applied and incorporated in the same plots repeatedly over three crop cycles at rates of 9, 18, 36, and 54 Mg·ha–1 (dry mass) in each application. In the first crop cycle, no differences were observed for weekly soil NO3-N, NH4-N, or leaf lettuce yield among compost types or rates. In the second and third crop cycles, weekly soil NO3-N and soil NH4-N were directly related to LoCN compost application rates. First harvest lettuce yield was also directly related to LoCN rate in the second and third cycles, but total yield was not related to LoCN rate. In the second and third cycles, soil NO3-N and early and total lettuce yield were inversely related to rate of application of the HiCN material. Weekly soil NH4–N was not consistently related to application rates of HiCN or LoCN material.
Nutrient Application Reduction to Vegetable Production Land Through Soil Testing and Demonstration Plots
Authors: White J.M. , Neal C.A. , Hanlon E.A. , Cox S.
Published: February 2019

A cooperative project between the Univ. of Florida Cooperative Extension Service, USDA Natural Resources Conservation Service, and Consolidated Farm Services Agency to address farm nutrient use and water management in the Lake Apopka hydrologic unit area of Florida began in 1991. This area was selected due to the vegetable production on the organic soils (muck) and sandy soils north of Lake Apopka, Florida's most polluted large lake. Discharge of nutrient-laden water into the lake from the 4050-ha vegetable production area has been implicated as a major contribution to the hypereutrophic status of the lake. Changes in cultural practices including water management, which would lead to a reduction in nutrient loading, should aid in the restoration of the lake. A grower survey of fertilizer application rates was conducted each year for 4 years with the baseline established by the 1991 survey. Demonstration plots using soil tests as the basis for fertilizer rates compared to normal grower rates of fertilizer were established for carrots, sweet corn, and celery. In 1995, muck growers had reduced their total application of N by 16%, P 52%, and K 32%, without reducing yields or quality. Nutrient applications were reduced by over 656 t/year over the years surveyed. Farms have saved fertilizer and reduced environmental risks.
Ecologically Sound and Aesthetically Pleasing—Aesthetic Design for Effective Wildlife Habitats
Authors: Kyber-Robison Ashley
Published: February 2019

In the past decade, there has been a growing trend toward conservation and management of wildlife and the environment. Growing suburban development has increased displacement of native animals from their natural habitats; thus, there is an ever-increasing need to manage not only existing forests and large land holdings for wildlife but also developed land areas. The idea of “backyard habitat” gardening and the “green movement” in golf course design address these issues of wildlife habitat and provide design solutions that hail the growing need for natural habitats. The same principles also can be used in commercial landscape design and ultimately in reclaiming grazing pasture land for dual habitat by farm animals and native wildlife. Just as the “American Lawn” provides minimal support for wildlife due to its lack of diversity, the manicured pasture of the American farm can also be limiting for wildlife. Providing areas of cover for nesting and protection can benefit the “kept” and “unkept” animals inhabiting the area. Furthermore, the biophilic landscape provides a psychologically healthy biosphere for the personnel working on the farm. In designing landscape plans with the primary goal of aesthetic enhancement of university experimental research farms, the principals of water conservation, integrated pest management, and providing wildlife cover and food are applied to develop an aesthetically pleasing design that also provides habitat for displaced wildlife. The intent of the project is to explore the possibilities in designing successful habitats for wildlife while preserving the ultimate goal of livestock production. Implementing successful ecologically sound landscapes enable the land-grant university to teach the public the benefits of wildlife conservation and the importance of its incorporation to all aspects of land use.
Using Leaf Chlorophyll Meter to Predict Nitrogen Status and Yield of Grapefruit Trees
Authors: Li Y.C. , Alva A.K. , Calvert D.V. , Zhang M.
Published: February 2019

Rapid and accurate diagnosis of plant nutrient deficiency is critical for growers to use fertilizer economically and to minimize environmental concern. The objective of this study was to evaluate the use of leaf chlorophyll meter (SPAD-502) to predict nitrogen status and yield response of grapefruit trees. The study includes two irrigation treatments, three fertilizer sources, and four fertilizer rates. No significant differences in SPAD readings and leaf N were found between two irrigation treatments. Correlations between SPAD readings and leaf N were higher for the spring flush (r = 0.61) than that for summer flush (r = 0.49). There were poor relations between SPAD meter readings and the extractable chlorophyll content in the spring flush on a dry-weight basis (r = 0.25). Higher correlations between SPAD meter readings and N rates or fruit yields than between leaf N concentrations and N rates or fruit yield.
Effect of Foliar Boron on Fruit Yield and Quality of Citrus sinensis cv. Hamlin
Authors: Karim Mohammad R. , Wright Glenn C. , Taylor Kathryn C.
Published: February 2019

A field trial conducted at Yuma, Ariz., examined the effect of foliar boron application on fruit yield and quality of Citrus sinensis cv. Hamlin. Boron was applied to 5-year-old trees at five treatment levels (0, 500, 1000, 2000, and 3000 ppm) before or after flowering in a split plot design. At harvest, fruit number, size and quality were determined. Yield (P = 0.01) and average fruit number per tree (P = 0.02) were different among treatments. The highest yield was obtained with the 500 ppm treatment. In this first year of the trial there was no difference in average fruit weight, fruit pH, titratable acidity, peel thickness, juice volume, or soluble solid content of fruit between the treatments. Previous studies indicate that boron influenced in vivo and in vitro pollen germination in many crops. Increased fruit yield may have occurred because boron was transported to the flowers where it exerted its influence on increased fruit set through an effect on pollen viability or pollen tube growth. Further investigation of this hypothesis is underway.
Aluminum and Phosphorus Interactions in Mycorrhizal and Nonmycorrhizal Highbush Blueberry Plantlets
Authors: Yang Wei Qiang , Goulart Barbara L. , Demchak Kathleen
Published: February 2019

Aluminum and P interactions were investigated in mycorrhizal (M) and nonmycorrhizal (NM) highbush blueberry plantlets in a factorial experiment. The toxic effects of Al on highbush blueberry were characterized by decreased shoot, root, and total plant dry weight. Many of the negative effects of Al on plant root, shoot, and total dry-matter production were reversed by foliar P and N application, indicating P or N uptake were limited by high Al concentration. However, Al mediated growth reduction in P-stressed plants suggested that the restriction of P uptake by high Al may not have been the only mechanism for Al toxicity in this experiment. Root Al and P concentration were negatively correlated in NM plantlets but not in M plantlets, suggesting mycorrhizal infection may alter P uptake processes. Al uptake also was affected by M infection, with more Al accumulating in M plantlet roots and leaves. Correlations among foliar ion concentrations were also affected by M fungal infection.
Effects of Calcium on Yield and Incidence of Blossom-end Rot of Three Tomato Cultivars
Authors: Hadi Muhammad S. , Conway William S. , Sams Carl E.
Published: February 2019

An experiment was conducted to investigate the effect of Ca nutrition on yield and incidence of blossom-end rot (BER) in tomato. Three levels of Ca (low = 20 ppm, medium = 200 ppm, and high = 1,000 ppm; selected to represent very deficient, normal, and very high levels of calcium) were applied to three cultivars of tomatoes (`Mountain Supreme', `Celebrity', and `Sunrise'; selected to represent genetic differences in susceptibility to BER) grown in modified Hoagland solutions using a greenhouse hydroponic system. The experiment was constructed in a randomized complete-block design with three blocks, two replications, three cultivars, and three calcium treatments. The source of basic nutrients was a 5–11–26 soluble fertilizer containing micronutrients. The ratio of N–P–K was adjusted to 1.0–1.3–3.0 by adding NH4NO3 (34% N). Calcium was added as CaCl2. Nitrogen concentrations were maintained at 30 (first month), 60 (second month), and 90 ppm (during fruit growth), while the concentration of other nutrients followed proportionally. Cultivars differed significantly in yield and average fruit weight but not in incidence of BER or leaf Ca concentration. There was no cultiva × calcium treatment interaction. Leaf Ca content across cultivars was increased by 34% and 44%, respectively, by the medium and high Ca treatments. Average fruit weight and total yield per plant were not significantly different between the low and medium Ca treatments, however, both were reduced by the high Ca treatment. Incidence of BER was 95% higher in the low rather than in the medium Ca treatment. There was no significant difference in BER between the medium and high Ca treatments.
A Recirculating Hydroponic System for Micronutrient Studies on Rapid Cycling Brassica and Its Experimental Evaluation
Authors: Lownds Norman K. , Kennedy Larry S. , Sams Carl E.
Published: February 2019

Rapid cycling brassica (RCB) plants, because of their short life cycle and ease of growth under laboratory conditions, offer a valuable tool for studying Brassica nutrition. We have been particularly interested in B nutrition in Brassica and, therefore, a hydroponic system was developed to accurately deliver micronutrient concentrations to RCB plants. RCB plants were supported in predrilled holes in the lids of brown 1-L plastic containers. Nutrients were supplied by spraying a modified Hoagland's solution onto the plant roots as they developed inside the containers. This system provided adequate solution aeration for plant growth and allowed analysis of both plant shoots and roots. RCB seeds were pregerminated for radicle emergence, then placed in the holes in the plastic container lids. The effect of B nutrient concentration on B uptake was examined using nutrient solutions containing 0.08, 0.02 and 0.00 ppm added B. Leaf B contents were 139.5, 26.1, and 7.1 g·g–1 for plants grown in 0.08, 0.02 and 0.00 ppm added B, respectively. Effects of drought stress on B uptake and distribution were studied by adjusting nutrient solution osmotic potential using polyethylene glycol (PEG) 8000. PEG-induced drought, (osmotic potential –0.1 MPa) reduced leaf and root B content ≈50% compared to plants grown in nutrient solution only (–0.05 MPa). Boron content in the shoots and pods, however, was not affected by PEG-induced drought stress. These results suggest that this system provides a reliable tool for studying nutrition and drought stress effects using RCB plants.
Effects of Water Stress on Boron Partitioning and Glucosinolate Composition in Two Hydroponically Grown Canola Cultivars
Authors: Kocourkova Barbara , Charron Craig S. , Graves Charles , Lownds Norman K. , Sams Carl E.
Published: February 2019

High glucosinolate content in brassica meal is a limiting factor in consumption of rapeseed. In recent years canola cultivars of rapeseed with decreased glucosinolate content have been developed. However, environmental and nutritional factors are also believed to influence glucosinolate content. This study was conducted to determine the relationships among water stress, B nutrition, and glucosinolate content in canola. Two canola cultivars (`Cyclone' and `American A112') were grown in a continuously recirculating hydroponic system with modified Hoagland solution (0.6 ppm B). Water stress was induced gradually (2% per day using polyethylene glycol 8000) starting when plants were 4 weeks old. Osmotic potential was maintained at –0.1 MPa (high stress level), –0.085 MPa (medium stress), or 0.05 MPa (control). Treatments were arranged in a randomized incomplete-block design, with three blocks, four replications, two cultivars, and three treatments. Upper leaves (no. 15 and higher) were collected and analyzed by inductively coupled plasma emission spectrometry for B content. Total and indole glucosinolate content of seeds were measured colorimetrically and by HPLC. The leaf B content of stressed plants decreased by 55% in `Cyclone' and 29% in `American A112'. Total glucosinolate content increased 28% and 12%, respectively, in stressed plants of `Cyclone' and `American A112'. Indole glucosinolate content was 44% and 13% higher in the same plants. The interaction between cultivar and water stress was not significant for glucosinolate content but was significant for B content of the leaves.
Influenced of Plant Production and Nitrogen Fertilization Rates on the Yield of Garlic (Allium sativum L.)
Authors: Arboleya Jorge , Garcia Claudio , Suarez Carlos
Published: February 2019

National Research Inst. of Agriculture of Uruguay defined garlic as an important crop because its potential for exportation. Plant population and N management have been studied since 1992. Plant population of 112, 250, 333 and 500 thousand plants/ha at rates of N at 0, 75, 150 and 225 kg·ha–1 were tested in 1992, 1993, and 1995. Drip irrigation and plastic mulch with populations from 240 to 960 thousand plants/ha in 1992 and from 236 to 586 plants/ha in 1993 were evaluated. Nitrogen rates of 0, 40, 80 and 120 kg/ha, and application times were also tested with a population of 250 thousand plants/ha, in 1992 and 1993. Plant population of 240, 320 and 560 thousand plants/ha yielded 12,0; 12,4 and 14,2 t·ha–1 respectively. As plant population increased, bulb size decreased. Yield increased up to rate of N at 150 kg·ha–1.
Seasonal Patterns of Nitrogen Use in Three Woody Ornamentals
Authors: Biernacka Barbara , Rose Mary Ann
Published: February 2019

Seasonal patterns of N uptake and allocation in Buxus microphylla, Acer × freemanii and Fothergilla gardenii were investigated for improving fertilization strategies. Rooted cuttings were planted to 3.5-L containers 25 May 1995. Plants were drip-irrigated on an as-needed basis with N at 50, 100, or 200 mg·L–1 solutions. Leaves, stems, and roots were destructively harvested every 6 weeks, starting 24 June. Net changes in dry weight and N uptake were determined for each of four, 6-week periods. Increasing N rate increased tissue N concentration in all species, and reduced root: shoot ratios in Acer and Fothergilla. Dry weights of Acer increased with N rate; whereas other species gave no positive response in dry weight beyond N at 100 mg·L–1. Nitrogen at the 200-mg·L–1 rate caused severe injury to Fothergilla. Nitrogen uptake of the deciduous species increased in the first three periods, with greatest N uptake between 1 Sept. and 12 Oct. Greatest N uptake in Buxus occurred between 15 July and 1 Sept. Total N content in Buxus increased between 15 Oct. an 1 Dec. with a large proportion of N appearing to shift from leaf to stem tissue. In the other species, leaf abscission caused a net reduction in total N contents in the 100 and 200 mg·L–1 rates, although stem and root N contents increased. Increasing N rate in Acer delayed fall coloration but hastened leaf abscission. End-of-season N recovery (N taken up/N applied) was extremely low, and decreased with increasing rate of N. Acer had the highest recoveries (4.1%, 2.6%, and 2.0%) for low, medium, and high fertilizer rates, followed by Buxus (2.6%, 2.2%, 1.0%) and Fothergilla (1.7%, 1.8%, 0.4%).
Nutrient Uptake Patterns in Forsythia
Authors: Wang Hao , Rose Mary Ann
Published: February 2019

Nutrient uptake and allocation patterns of Forsythia ovata × europaea `Meadowlark' grown in a recirculating hydroponic system in the greenhouse were observed for 5 months. Dormant rooted cuttings were placed in the system on 8 May 1995. The nutrient solution supplied (in mg·L–1) 100 N, 48 P, 210 K, 30 Mg, 60 Ca, 117 SO4, 3 Fe, 0.5 Mn, 0.15 Zn, 0.15 Cu, 0.5 B, 0.1 Mo. Solutions were completely replaced every 2 weeks. Leaves, stems, and roots were harvested for dry weight and nutrient analysis at monthly intervals. Nitrogen uptake and dry-weight accumulation in the roots increased throughout the experiment, reaching a maximum in the fifth month (September). Nitrogen uptake and dry-weight accumulation of leaves and stems increased rapidly throughout the first 3 months, then leveled off. Whole-plant N recovery (N taken up/N in hydroponics system) reached a maximum (58%) between 6 July and 3 August. N recovery in the hydroponics system was about 10 times greater than what we observed in related experiments with woody plants in typical production environments, suggesting that there is potential for manipulating fertilization and cultural practices to increase fertilization efficiency in woody ornamentals. Nutrient recovery and accumulation patterns of P and K also will be presented.
Does Nitrogen Nutrition in the Nursery Affect Plant Establishment and Performance in the Landscape?
Authors: Cabrera Raul I. , Devereaux Diana
Published: February 2019

Ilex opaca and Lagerstroemia indica plants were grown over 9 months using complete nutrient solutions differing in N concentration [(N)A: 15, 30, 60, 120, 210 and 300 mg·L–1]. Biomass production increased as (N)A were raised from 15 to 60 mg·L–1, but was depressed by higher concentrations. Increases in (N)A produced higher shoot: root ratios. Maximum leaf N concentration was observed at 60 mg·L–1, with similar values at higher (N)A. Plant survival, establishment and performance was evaluated over 15 weeks following transplant (15 WAT) to a landscape with minimum management conditions. Despite the initial significant differences in growth, shoot: root ratios and plant N status, plant establishment was not affected following transplant. Plant characteristics changed significantly over time, and by 15 WAT, all of the measured variables were statistically the same across all treatments. Flowering was, however, delayed over several weeks for Lagerstroemia indica plants grown at the higher (N)A. Analysis of these results indicate that plant production under relatively low N levels in the nursery maximizes N fertilizer use efficiency without affecting landscape establishment and performance.
Nitrogen Mineralization and Immobilization and Plant Growth Response to Nitrogen Fertilization in Potting Media Containing Compost.
Authors: Sanchez-Escarcega Alicia , Elliott George C.
Published: February 2019

The potential for N mineralization or immobilization in potting media containing compost was investigated in experiments using sunflower (Helianthus annuus `Sunrich Yellow') as a test crop with potting media formulated from 3 aged pine bark: 2 sphagnum peat or compost: 1 vermiculite (by volume). Cropped and uncropped media in 350-mL pots were fertilized by subirrigation with complete nutrient solutions containing N at 2, 4, 6, 8 or 12 mmol·L–1 as ammonium nitrate. In control medium without compost, sunflower fresh mass increased linearly with increasing N. In one compost medium (C), growth was stimulated and with N at 6 mmol·L–1 was equal to growth with N at 12 mmol·L–1 in the control medium. With another compost medium (A), growth was inhibited and did not respond to increasing N. In medium C, saturated media extracts (SME) obtained before and up to 12 days after transplanting had higher concentrations of NH4 and NO3 than the control medium. In medium A, NH4 concentrations were similar to controls, but NO3 concentrations were lower. Nitrite concentrations were less than 0.2 mmol·L–1 and were highest in medium C. Nitrogen derived from compost in medium C substantially reduced the soluble fertilizer N requirement for sunflowers, while N immobilization by compost in medium A was not overcome by increasing fertilizer N.
Performance of Nine Apple Cultivars Grown with Six Fungicide Regimes
Authors: Marini Richard , Barden John , Sowers Donald
Published: February 2019

In 1993 a factorial experiment, involving nine apple cultivars on M.9 root-stock and six fungicide regimes, was established. The cultivars included `Delicious', `Golden Delicious', `York Imperial', `Redfree', `Freedom', `Liberty', NY 74828-12, NY 73334-35, and NY 74840-1. The fungicide treatments included earlyseason sprays of Bayleton or Dodine, separately or combined, and late-season sprays of Captan plus Benomyl alone or combined with early-season sprays of Bayleton plus Dodine. Non-sprayed trees served as a control. In 1995 leaves and fruits were evaluated for disease symptoms. Leaf spot (symptoms caused by black rot or alternaria leaf blotch) was most severe on `Redfree' and NY 73334-35, and least severe on `Delicious', `Golden Delicious', and `York'. By late summer NY 74828-12 had the most leaf abscission, whereas NY 74840-1, `Liberty', and `Delicious' lost the fewest leaves. Early-season fungicide sprays did not reduce early leaf abscission. Sooty blotch and fly speck, but not rots, were nearly eliminated by late-season applications of Captan plus Benomyl. Averaged over all fungicide treatments, more than half of the fruits from `Delicious', `Redfree', and NY 74828-12 were free of disease symptoms. Cultivars with <25% of the fruits without infection included `York', `Liberty', NY 74840-1 and NY 73334-35. `York' and `Redfree' had >25% of the fruits with rots, while all other cultivars had <9% fruits with rots. `Delicious' and NY 73334-35 had the fewest rotten fruits. Rots were not controlled by any fungicide treatment. `Liberty' and NY 73334-35 had the most flyspeck and `Redfree' had the least. `Liberty', NY 74840-1 and NY 73334-35 had the most sooty blotch and `Redfree' and NY 74828-12 had the least.
Differential Yield Response Of Melon Hybrids with Monosporascus Root Rot/Vine Decline
Authors: Wolff David W. , Miller Marvin E.
Published: February 2019

Monosporascus root rot/vine decline (MRR/VD), caused by Monosporascus cannonballus, is a serious disease of the major melon production areas of Texas, California, and Arizona. We have previously identified differing levels of tolerance in melon germplasm based on vine disease symptoms. This study was conducted to evaluate the yield response of commercial and experimental cantaloupe and honeydew hybrids subjected to MRR/VD. Thirty-nine and six cantaloupe and honeydew hybrids, respectively, were transplanted into a field highly infested with M. cannonballus in March 1995 in a randomized, complete block with 4 replications. The field was highly infested with Monosporascus cannonballus. `Caravelle' (very susceptible) and `Deltex' (tolerant) were included as control entries. Fruit were harvested at maturity and sized. Any fruit that did not mature completely due to vine death were counted as culls (unmarketable). Marketable yield of the cantaloupe entries ranged from 26.74% to 67.35%. The most tolerant hybrids were `SR103654', `Don Carlos', `Explorer', and `Ovation'. Marketable yield of the honeydews ranged from 8.43% to 41.46%, with `Morning Ice' and `Creme de Menthe' showing the most tolerance. The best performing hybrids were evaluated again the Fall 1995 and Spring 1996 seasons. In general, genotypes which matured later, and had a more dispersed fruit set, were more tolerant to MRR/VD. This supports previous data showing that high physiological stress (heavy, concentrated fruit load) leads to more severe and rapid vine collapse.
Symptom Development and Susceptibility of Dwarf Cherry Tomato to Tomato Irregular Ripening, A Fruit Disorder Induced by Silverleaf Whitefly
Authors: Hanif-Khan S. , Bullock R.C. , Stoffella P.J. , Brecht J.K. , Powell C.A. , McAuslane H.J.
Published: February 2019

Silverleaf whitefly (SLW) (Bemisia argentifolii Bellows and Perring) feeding has been associated with development of tomato irregular ripening (TIR) symptoms. Four dwarf cultivars of cherry tomato (Lycopersicon esculentum L.) were infested with adult SLW to observe oviposition preference, tolerance and TIR symptom development. Oviposition preference was observed at low SLW population. Florida Petite was the most preferred and Micro-Tom the least preferred cultivar, with Florida Lanai and Florida Basket intermediate. Each cultivar exhibited TIR symptoms associated with feeding by the SLW. TIR fruit symptoms were expressed as longitudinal red streaks with yellow, green, pink or red blotches externally, and white, yellow or green tissue internally. External TIR symptoms ranged from 32% (Micro-Tom) to 82% (Florida Basket). However, external symptoms disappeared from 34% (Florida Lanai) to 56% (Micro-Tom) of the fruits during ripening. SLW infested plants had 82% (Florida Lanai) to 99% (Florida Basket) of fruits with internal white tissue regardless of external symptoms. Tomatoes with TIR symptoms rarely ripened to a mature red, and sometimes had empty locules, were smaller in size and were seedless.
Pepper (Capsicum spp.) Wound Volatiles Suppress the Growth of Alternaria alternata, the Causal Agent of Internal Mold of Pepper
Authors: Vaughn Steven F. , Eller Fred J.
Published: February 2019

Internal mold of sweet and hot peppers (Capsicum spp.) is caused by the pathogen Alternaria alternata. The pepper weevil, Anthomonus eugenii Cano (Coleoptera: Curculionidae), is an important pest of peppers in the southern U.S., Mexico, and Central America, and has been implicated in the transmission of the disease. We identified several volatiles released by pepper fruit during wounding by pepper weevils, including (E)-3-hexenyl acetate, linalool, beta-ocimene, and 3,7-dimethyl-1,3,6 octatriene (homoterpene). To study the roles of these volatiles in the interaction of the plant and fungus, we determined their effect on the growth of isolated cultures of A. alternata. Fungi were unaffected by any of the compounds when exposed to individual volatiles at 1 ppm; however, a 1 ppm mixture of the four compounds significantly reduced growth. All four compounds were inhibitory individually at 10 ppm, with linalool completely inhibiting fungal growth. These results indicate a role for these volatiles in the plant's response to infection by A. alternata.
Transmission of Prunus Necrotic Ringspot into Three Peach Scion Cultivars, Measured by RNA Hybridization following in Vitro Micrografting
Authors: Heuss Kathleen , Liu Qingzhong , Hammond Rosemarie , Hammerschlag Freddi
Published: February 2019

As part of our program to develop transgenic peach cultivars with improved disease resistance, we showed that grafting of in vitro cultured `Suncrest' peach [Prunus persica (L.) Batsch] tips `onto decapitated stems of Prunus necrotic ringspot virus (PNRSV) infected `Suncrest' shoot cultures, resulted in consistent transfer of virus across grafts as demonstrated by RNA hybridization analysis, suggesting that such a system could be useful for measuring resistance to PNRSV in peach shoot cultures. We have extended these studies to include grafts of `Springcrest' and `Nemaguard' test tips onto `Suncrest' stocks. RNA hybridization analysis showed that PNRSV persists in shoot cultures for 18 months after initiation from PNRSV-infected `Suncrest' trees and after 16 weeks of treatment of 4°C in the dark, suggesting that a supply of infected shoot cultures could be maintained for repeated use. Graft success rates for grafts of `Springcrest' onto `Suncrest' and `Nemaguard' onto `Suncrest', equaled or exceeded success rates for `Suncrest' onto `Suncrest'. Virus was transmitted from infected stocks into `Suncrest', `Springcrest', and `Nemaguard' test tips by 2 weeks in most successful micrografts. There was no significant difference in the virus concentrations among the three scions at 2, 4, and 6 weeks after grafting, suggesting that there is equal efficacy of virus transfer through grafts from `Suncrest' to the three cultivars, and that no differences in resistance to PNRSV exist among these cultivars.
Diurnal Temperature Alterations Influence Final Height of Herbaceous Perennials
Authors: Hamaker Cheryl , Carlson William H. , Heins Royal D. , Cameron Arthur C.
Published: February 2019

DIF is the difference between day (DT) and night (NT) temperatures. Temperature drop is a 2-hour temperature reduction at sunrise. DIF and temperature drop, which can be affected by light quality, are effective methods to control final plant height of many greenhouse crops. The effect of DIF and temperature drop on final height was determined for eight species of perennials. Durations for DIF temperatures were 12 hours for both DT and NT. Temperature alterations occurred at sunrise. Temperature treatments (DT/NT) consisted of zero DIF (20/20°C), negative DIF (16/24°C), or positive DIF (24/16°C), and a 2-hour drop (12.7/20.7°C). Long days (LD) were provided from 2200-0200 hr by either cool-white fluorescent (CWF) or incandescent (INC) lights. Data for days to visible bud and anthesis, bud number, and final height were collected. Positive DIF conditions enhanced elongation while negative DIF reduced it in all species. As DIF decreased from positive to negative, plant height was reduced 10%, 30%, 30%, and 20% in Coreopsis `Moonbeam' and `Sunray', Delphinium `Belladonna', and Scabiosa `Butterfly Blue', respectively. Negative-DIF responses were enhanced under CWF lights for some species. In negative-DIF conditions, Coreopsis `Moonbeam' and `Sunray' and Delphinium `Belladonna' were 10%, 10%, and 15% shorter, respectively, under CWF lights than INC lights.
Control of Leaf Senescence of Easter Lily using Plant Spacing and Early Applications of Promalin
Authors: Sherratt Mark D. , Pitchay Dharmalingam S. , Bearce Bradford C.
Published: February 2019

Easter lilies (Lilium longiflorum Thunb. `Nellie White') were placed at three spacings of about 11, 22, or 44 plants per square meter (plants/m2). Above canopy light intensities, measured weekly at noon, ranged from 107.3 to 704.5 μmol·s–1·m–2 and were not significantly different among spacings. Mid canopy light intensities ranged from 16.5 to 229.0, 43.0 to 458.5, and 77.5 to 535.3 μmol·s–1·m–2 at spacings of 44, 22 and 11 plants/m2, respectively. On February 5, 1996, three plants from the 22 plants/m2 spacing were sprayed with a solution of 0.5 ml·L–1 of 1.8% (a.i.) of each of N-(phenylmethyl)-IH-purine-6-amine and gibberellins A4A7; and on March 5, three additional plants from each spacing were similarly sprayed. Beginning 5 Mar., weekly counts were made of yellow and brown leaves on all treated and control plants. Average per plant numbers of brown leaves increased on control plants at all spacings but increased on treated plants only at the 11 plants/m2 spacing. On 25 Mar., control plants averaged 15.6, 12.1, and 15.3 brown leaves per plant at spacings of 11, 22, and 44 plants/m2, respectively, while plants treated on March 5 averaged 10.7, 9.0, and 10.7 brown leaves. Plants treated on 5 Feb. averaged 3.5 brown leaves per plant and had an average mid leaf length of 13.8 cm compared to about 10.5 cm for all other plants. Spacing had no effect on average yellow or brown leaves per plant. This study demonstrated that early applications of Promalin can reduce leaf senescence which may occur during forcing time before bud appearance to opening of first bud. Some leaf enlargement may occur on plants treated very early.