bluuebunny/crossref_metadata_2025 huggingface dataset:
Study and Comparison of Different Methods of Nonsexual Propagation of F12/1 and Colt Rootstocks of Cherry
Authors: Talaie A. , Gholi Sh. Khan
Published: February 2019

This research work was carried out for 2 years at Kelardasht-Mazandaran and Mardabad-Karaj Agricultural Research Stations to evaluate the rooting of selected and hybrid F12/l and Colt rootstocks under climatic conditions of Iran. Young F12/l and colt rootstocks (semi-hard wood and summer cuttings) available in Kelardasht Agricultural Research Station were used These rootstocks were also used for layering. Summer cuttings were taken in early July and, after wounding, were treated with IBA with 1000, 2000, and 3000 ppm and then put under mist. Three months later the rooted cuttings were evaluated on the basis of rooting percentage, number and the length of the main and the lateral roots and the length of the rooted section. The hardwood cuttings were prepared in two intervals (early Dec. and late March) and, when wounded, were treated with IBA with the same concentrations. Finally, the experiments were completed by horizontal layering of several rootstocks and covering them with soil. The results were used in a completely randomized block design in four treatments, and the averages were compared by Duncan test. The results indicate that the summer cuttings treated with 1000 ppm IBA have the highest rooting percentage in both rootstocks, while those treated with 2000 ppm gave the best results with regard to number and the length of the main root. The best result on the number and the length of the lateral roots are achieved in cuttings treated with 2000 ppm IBA. Number and the length of lateral roots in Colt and F12/l rootstocks are, respectively, high in cuttings treated with 2000 and 3000 ppm. IBA. In semi-hardwood cuttings, different concentrations of IBA were effective on callus formation and budbreak. Thus, there were more callus formation in high concentration and the number of budbreaks was reduced. Study on the layering method indicates that there are 6.1 and 3 rooted cuttings in every Colt and F12/l layered rootstocks respectively. The rooting percentage in the said rootstocks is 100% and 73.3%, respectively.
Effects of Sprouting Inhibitors and Reconditioning Conditions on Tuber Quality of Processing Potato
Authors: Hak-Tae Lim , Mi Choi Yu
Published: February 2019

This study was conducted to find out the effect of sprouting inhibitors under different storage temperatures and reconditioning conditions on the processing quality of potato tubers produced in the alpine area of Korea. A higher sprouting ratio was observed in potatoes stored at 15°C than those at 5°C. In particular, 1% CIPC, was effective in the inhibition of sprouting, keeping the sprouted shoots in less than 2 mm, while rosette-shaped shoots, 12–17 mm, were observed in the CMH (100%) treatment. Atlantic was, in general, lower in reducing sugar contents compared to Superior. Reducing sugar contents in potatoes stored at 15°C were not increased, while potatoes stored at 5°C showed a 1% increase in reducing sugar contents for 180 days after storage. As far as chip color “L” value was concerned, no difference was detected among potato cultivars and sprout inhibitor treatments. Potato chip color was found to be the best from potatoes stored at 15°C for 180 days of storage. However, potatoes stored at 5°C gave rise to poor quality of potato chips with browning and bitter taste. Reconditioning had different effects on potato cultivars in that Atlantic potatoes produced more sprouts when they were reconditioned compared to the control of 15°C potato storage. In terms of the effect of reconditioning on reducing sugar contents, Atlantic sugar contents was reduced reconditioning went on. Sugar contents of Superior, however, was increased after undergoing the decrease for some time. Changes in potato chip color as influenced by reconditioning were in accordance with changes in reducing sugar. Atlantic was much better in chip color than Superior, showing a chip color “L” value of more than 50 in all treatments.
Evaluation of Stem and Flower Strength of Different Freeze-dried Peony Cultivars
Authors: Gast Karen L.B.
Published: February 2019

The floral industry is always trying to identify new products for consumers. Dried/preserved products have gained in popularity because they have a long vase life and offer a wide range of forms, textures and shapes. Among these new dried/preserved products are freeze dried flowers. Freeze drying preserves flower color and shape better than air and matrix drying. From a grower's standpoint, they need to know which plants and which of their cultivars will freeze dry better than others, especially if the plant is a perennial that takes time to come into production. Peonies are a good example. Fragility of the flowers after freeze drying is one of the most important factors determining the suitability of a plant and its cultivars. The objective of this study was to evaluate the flower and stem strength of freeze dried peony flowers of several cultivars to be able to recommend to growers which cultivars freeze dried better than others. Flowers from different red, pink and white herbaceous peony cultivars were freeze dried using commercial equipment and protocols. Stem and flower strengths were determined by compression tests via an Instron Universal Testing Machine. There were no differences in flower strength among the white cultivars evaluated. Flowers of the red cultivars, `Shawnee Chief', `David Harum', `Kansas', and `Monsieur Martin Cahuzac', were stronger than most of the other reds evaluated. `James Pillow' flowers were stronger than most other pinks. There were no differences in flower strength among the other pink cultivars. Lack of differences in flower and stem strength provides growers with a wider selection of suitable cultivars.
Estimation of Anthocyanin Concentration from Colorimeter Measurements of Raspberry Fruit.
Authors: Moore Patrick P.
Published: February 2019

Measuring intact fruit with a colorimeter could be a quick way to estimate anthocyanin concentration and reduce waste disposal. Five fresh fruit from each of 134 plots were measured with a Minolta tristimulus colorimeter in 1994. Samples were frozen and anthocyanins extracted with acidified ethanol and measured with a spectrophotometer. The hue angle and anthocyanin concentration had r2 = 0.51. L*, a*, b* and C* were significantly correlated with anthocyanin concentration with r2 = 0.31, 0.32, 0.42, and 0.34, respectively. In 1995, five fruit from each of 20 plots were measured as before. In 1995, the hue angle and anthocyanin concentration had r2 = 35. A regression equation with hue angle, b* and a* estimated anthocyanin concentration with R2 = 0.62. In 1995, the same 20 samples were also measured with a colorimeter immediately after thawing. The hue angle and anthocyanin concentration had r2 = 0.55. A regression equation with hue angle, b* and L* estimated anthocyanin concentration with R2 = 0.76. It may be possible to estimate anthocyanin concentration by measuring intact fruit with a colorimeter after freezing and thawing the samples.
Physiological Response of Tomato Fruit to Ethylene at High Temperature
Authors: Masarirambi Michael T. , Brecht Jeffrey K. , Sargent Steven A.
Published: February 2019

Mature green fruit of `Agriset 761', `Colonial', `Sunny' and `Sunbeam' tomatoes were exposed to 100 ppm ethylene at 20, 25, 30, 35, or 40°C around 95% relative humidity (RH) for 24, 48, or 72 hours, then transferred to air at 20°C and 95% RH for ripening. There were few differences in ripening behavior in tomatoes exposed to ethylene at high temperatures (>30°C) for 24 hours compared to those treated at lower temperatures. However, increasing the duration of ethylene treatment at 35 or 40°C to 48 or 72 hours inhibited subsequent red color development, but prior exposure to ethylene at 30°C stimulated red color development. Ethylene production was inhibited after 48 or 72 hours at 40°C, but was stimulated by exposure to lower temperatures in the order shown: 35 > 30 > 25. During ripening, conversion of ACC to ethylene increased in fruit exposed to ethylene at 20 or 25°C but did not change in fruit from 30 or 35°C. ACC oxidase activity was lowest after exposure to 40°C. Untreated fruit ripened slowly and nonuniformly compared to those previously treated with 100 ppm ethylene. Increasing the ethylene treatment concentration to 1000 ppm did not alter the responses to high temperatures described above.
Comparison of Nutritional Composition of Two Edible Species of Cnidoscolus (Tree Spinach)
Authors: Kuti Joseph O.
Published: February 2019

The tree spinach (Cnidoscolus spp., Euphorbiaceae), called chaya in south Texas, is popular in Mexico and Central America and has been introduced into the United States (mainly Texas and Florida) for potential uses as a leafy vegetable plant. Nutritional composition of raw and cooked leaves of two chaya species (C. chayamansa and C. aconitifolius) were determined and compared with nutritional composition of spinach (Spinicia oleraceae). While the two chaya species contained substantially greater amounts of mineral nutrients and vitamins than spinach, no significant differences were found in the amounts of mineral nutrients and vitamins, except in relative compositions of fatty acids and amino acids, among the chaya species. Cooking slightly reduced nutritional composition of both chaya and spinach leaves. Because of the presence of toxic hydrocyanic glycosides in chaya leaves, cooking, which inactivates the toxic compound, is essential.
Sugars and Acids Influence Flavor Properties of Mango (Mangifera indica L.)
Authors: Malundo T.M.M. , Baldwin E.A. , Shewfelt R.L. , Sisson H. , Ware G.O.
Published: February 2019

Fruit flavor is a function of sensory perception of taste, aromatic and chemical feeling factor components in the mouth. The specific role of sugars and acids in potentiating flavor perception of volatile compounds and chemical feeling factors is not well known for many fruits. This study was conducted to determine the effects of selected levels of sugars and acids on perception of 3 taste (sweet, sour, bitter), 6 aromatic (banana, grassy, orange peel, peach, pine/turpentine, sweet potato), and 2 chemical feeling factor (astringent, biting) flavor notes in diluted, fresh mango homogenate using a trained descriptive panel. Perception of all flavor descriptors except sour were enhanced by increasing the sugar concentration. An increase in acid concentration enhanced perception of sweet, sour and biting notes while lowering perception of the astringent, peach and pine/turpentine notes. Brix-to-acid ratio (BAR) was found to be an effective chemical indicator for perception of sourness but was not effective for perception of sweetness. These results provide insight into optimum balances of sugars and acids as they influence mango flavor perception specifically in preparation of juice blends, selection of cultivars for specific fresh markets, or determination of optimum ripeness in the marketplace.
Development of Indexes to Evaluate Hardiness of Rose Germplasm
Authors: Wang Mingqi , Peng Lixin
Published: February 2019

Physiological, biochemical and anatomical indexes were investigated for rose hardiness. It was found that bound/free water ratio, proline accumulation, photosynthetic rate, palisade/spongy tissue ratio, and lignification of winter-acclimated stems were heavily influenced by the temperature causing stem browning. Spongy cell volume and stem tenderness were inversely related to winter hardiness. Data generated from this research demonstrated that catalase stability, TTC reduction rate at 0°C, total photosynthetic rate, stem pith ray number, and leaf wax thickness are good indicators for rose hardiness to freezing temperatures. Two compound indexes were developed through the main component analysis. Based on the results obtained from 12 tested cultivars, these indexes are ideal to quantify hardiness of rose germplasm.
Cryopreservation of Dormant Vegetative Buds from Sour Cherry
Authors: Towill Leigh E. , Forsline Philip L.
Published: February 2019

The dormant vegetative bud method for cryopreservation has been successfully applied to many lines of apple. We examined this method for five cultivars (Kentish, Montmorency, Meteor, North Star, Schatten Morelle) of sour cherry (Prunus cerasus L.) with the aim of developing long-term storage at NSSL. Singlebud nodal sections (35 cm) were desiccated to 25%, 30%, or 35% moisture before cooling at 1°C/hour to –30°C and holding for 24 hours. Sections were then directly placed in storage in the vapor phase above liquid nitrogen (about – 160°C). Warmed samples were rehydrated and patch budded at Geneva to assess viability. Sections that were either undried, dried but unfrozen, or dried and cooled to –30°C survived very well. For samples then cooled to –160°C, highest viabilities for each line occurred with the 25% moisture level, although fairly high viabilities also were observed at 30% and 35% moistures. Cryopreserved buds from four lines directly developed into a single shoot; buds from Montmorency formed a shoot from a lateral within the bud, suggesting that the terminal meristem died but that axillary meristems within the bud survived and formed a shoot or multiple shoots. Nineteen lines were harvested in January 1996 for long term storage of sour cherry germplasm under cryogenic conditions.
Exploring Accessibility: A Hands-on Teaching Tool
Authors: Relf Diane , Clopton Catherine
Published: February 2019

As part of a horticultural therapy class assignment, groups of three to four students each spent 1.5 hours analyzing a Virginia Tech greenhouse while using various equipment to simulate disabilities that future clients may have. Their instructional goal was to analyze the greenhouse and area around for accessibility. The purpose of this assignment was to develop student insight into the handicapping impact that the environment and people can have on individuals with disabilities, student awareness of the need for and types of adaptations to facilitate horticulture for disabled individuals, and student empathy for future clientele. The results were the written comments from the students regarding the class. Their comments were most constructive and gave insight into the value of such an assignment for future use.
Consolidation of Agricultural Programs at Tennessee State University
Authors: Catanzaro C.J. , Fenderson C.L. , Sauve R.J.
Published: February 2019

The Dept. of Agricultural Sciences currently offers degrees at both the undergraduate and graduate levels. Undergraduate programs in Plant Science, Animal Science, and Rural Development were consolidated within the Dept. of Agricultural Sciences in the late 1980s due to the declining number of graduates. However, no personnel turnover or course changes occurred due to consolidation. Enrollment at the undergraduate level has doubled within the past 5 years. Student enrollment for Fall 1995 included 127 undergraduates and 31 graduate students. Graduation figures projected for 1995–96 include 26 undergraduates and 8 graduate students. Horticulture and Agronomy are now two of the concentrations available for the BS degree in Agricultural Sciences, and Plant Science is an option for the MS degree in Agricultural Sciences. Presently in the plant sciences there are approximately 30 undergraduates and 20 MS students. Faculty and professional staff affiliated with the Cooperative Agricultural Research Program are encouraged to submit teaching proposals to the 1890 Institution Capacity Building Grants Program, a USDA-funded competitive program for the agricultural sciences. Awards enable grantee institutions to attract more minority students into the agricultural sciences, expand institutional linkages, and strengthen education in targeted need areas. The Grants Program supports teaching projects related to curricula design, materials development, and faculty and student enhancement. Current teaching grants address graduate and undergraduate education in molecular biology and undergraduate education in soil sciences.
Indian Floriculture Industry is Poised to Bloom
Authors: Thomas Joseph
Published: February 2019

Floriculture is growing at a frenetic pace in India. From a few units in 1990, nearly hundred units are either fully operational or at various stages of implementation. Almost seventy of these produce rose for the cut flower export market. The average unit size is two hectare under poly-cover. Anthurium, carnation, chrysanthemum, orchids and gerbera comprise the other cut flower producing units. Technology has come mostly from Holland, with Israel now giving severe competition to the Dutch. Germany, France, United Kingdom, and New Zealand are the other countries involved in technology transfer. Many units have the fan and pad system for temperature control along with drip irrigation and computer mediated operations. Most units use natural soil as the medium of growth whereas some have a combination of sand and natural soil and a few have adopted complete sand bed culture as practiced by Israeli growers. These hybrid as well as the state-of-the-art floriculture technologies are competing for the Indian market and the next few years will determine the system that is most suitable for adoption under local conditions. The Agricultural and Processed Food Products Export Development Authority (APEDA), a wing of the Commerce Ministry of the Government of India, and the National Horticulture Board have indeed provided substantial support for the growth of Indian floriculture Industry. Meanwhile, more and more entrepreneurs are, on their own, setting up cold storages and operating cold trucks near major airports to maintain appropriate temperatures from harvest to destination. It is widely expected that more than 50% of the existing floriculture units will make good whereas the remaining may not survive either due to sourcing of unsuitable technologies or lack of expertise in floriculture production and management as well as international marketing prowess. There is also consensus that no single foreign technology giver is capable of meeting adequately the total needs in the Indian context and often it is a matter of the collaborators learning together. What seems certain is that India will, by the year 2000, be a major player in international floriculture because of the diverse agroclimatically suitable locations, lower labor cost, and talented human resource.
Clemson University–Carolina Nurseries Partnership: An Innovative Approach to Improving Research and Outreach Programs
Authors: Whitwell Ted , Kelly John , Miller William B.
Published: February 2019

In 1993, Carolina Nurseries and the Department of Horticulture at Clemson Univ. entered into a partnership to create a research and development program to solve short and long term nursery production problems. Research is conducted on site at Carolina Nurseries in a specially designed 0.6-ha area built by the nursery. Faculty from the Depts. of Horticulture, Agricultural and Biological Engineering, Plant Pathology and Entomology have worked with graduate and undergraduate students located on site. The nursery staff is involved in overall planning and stay current with results so that research can be immediately implemented on the nursery. Yearly funding for the graduate student is provided by the nursery and grant funds are obtained from various companies for labor and supplies. Carolina Nurseries has committed to funding research to improve their production and also sharing the results with the rest of the nursery industry. Research findings are presented in peered reviewed articles, conference proceedings, abstracts, and oral presentations. Outstanding training opportunities for students and staff are available to also improve career development for future nursery managers. Faculty interaction with companies and the nursery industry are enhanced.
Art in the Garden: An Interdisciplinary Program for Educating Children about Horticulture
Authors: Uchneat Michael S. , Capezzuti Cheryl
Published: February 2019

Education of future consumers is a frequently discussed objective to improve consumer relations with the horticulture industry. We have developed a program which addresses this objective. The program provides examples of art projects that can be combined with simple horticultural experiences. We are presenting this program as a model to be used by horticultural professionals for the instruction of child care providers, or for direct presentation to children. Our intent is to create a greater awareness of horticulture. Often, child care providers plan educational experiences for young people based on disciplines that have been established by tradition and that are considered essential to childrens' educational development. For example, teachers might plan a nature lesson, a simple math lesson or an art lesson. This interdisciplinary plan helps children feel the connectedness of the world in which they live rather than seeing it as a series of unrelated events. Traditional motor skills are taught, along with an appreciation for seeds, plants, and the environment. Teachers may adapt the information presented here to a wide variety of activities. This approach can serve as an example of how interdisciplinary programs involving horticulture might be structured. It offers a timeline to teachers who desire to duplicate such a program, and presents many ideas, along with detailed information on how to conduct individual projects. Hopefully, this integration of art and horticulture inspires those who work with children to creatively consider the possibilities of interdisciplinary planning.
Introduction and Cultivation of Money Plant (Lunana annus) in Shandong, The People's Republic of China
Authors: Jianping Ding
Published: February 2019

Money plant may be a valuable plant to cultivate as an ornamental plant in China. Money plants are grown for the translucent, silvery, rotund, pseudo-septa that stay on flower stalks and are all that remain of ripened seed pods after the two outer coverings drop with the seeds. Money plant was first introduced from Canada into China in 1993. Seed germination and seedling development were successful. There were 18 to 34 leaves per plant and average plant height was 30 cm by the end of Nov. 1993. Plants exposed to environmental conditions (ENV) became dormant at low temperature. Plants grown under greenhouse conditions (GH) continued to grow until May. ENV plants escaped dormancy between April and May, grew normally, blossomed, and bore pods with seeds. GH plants blossomed; however, most of the blossoms dropped off and seed pods failed to develop. Flower stalks with many lateral inflorescences grew from ENV plant shoot apexes. In some cases, secondary and tertiary branches developed into the secondary and tertiary lateral inflorescences. There were ≈30 flowers per inflorescence and 30% of flowers were developed successfully into pods that usually contained five to six seeds with a maximum of nine seeds per pod. These results indicate that money plant may be successfully cultivated in Shandong, China.
Source and Processing Affects Chemical and Physical Properties of Coir Dust
Authors: Konduru Sreenivas , Evans Michael R.
Published: February 2019

Chemical properties of unprocessed coconut husks varied significantly between 11 sources tested. The pH was significantly different between sources and ranged from 5.9 to 6.9. The electrical conductivities were significantly different between sources and ranged from 1.2 to 2.8 mS·cm–1. The levels of Na, K, P, and Cl were significantly different between sources and ranged from 23 to 88, 126 to 236, 8 to 33, and 304 to 704 ppm, respectively. The B, Cu, Fe, Ni, S, Zn, Mn, and Mo levels were all significantly different between sources and ranged from nondetectable levels to 12.7 ppm. The NH4-N, NO3-N, Ca, and Mg levels were not significantly different between sources and ranged from 0.2 to 1.8, 0.2 to 0.9, 2.9 to 7.3, and nondetectable to 4.6 ppm, respectively. Coir dust produced by screening of waste grade coir through 13-, 6-, or 3-mm screens had significantly different bulk densities, air-filled pore space, water filled pore space and water-holding capacities compared to nonscreened waste grade coir. However, total pore space and total solids were not significantly affected by screening. Screen size did not significantly affect physical properties. Compression pressures used for formation of coir dust blocks significantly affected physical properties. Additionally, coir dust age significantly affected chemical properties.
Woody Ornamental Plant Response to Fertilization and Using of Organic Residues as a Partial Constituent of Substrate Mixtures
Authors: Bouden Mondher , Rioux Jacques-Andre
Published: February 2019

Large spaces are required to eliminate waste by burying and this method is very costly. The horticulture use of waste seems to be one of the best optional methods of disposal. This study was performed to evaluate the effects of fresh bio-filters (FBF), composted sewage sludges (CSS), and composted de-inked sludges (CDS) on growth of three woody ornamental species (Spiraea japonica `Little Princess', Spiraea nipponica `Snowmound', and Physocarpus opulifolius `Nanus') produced in containers. Three fertilization regimes (N at 200, 400, and 600 mg·L–1 in the form of soluble fertilizer 20–20–20) were applied weekly onto containers during 3.5 months. Plants were potted in 10 substrates. The control substrate contained 4 peatmoss: 5 composted conifer bark: 1 fine crushed gravel (by volume). In the other nine substrates, peatmoss was partially substituted by one of the three organic residues (10%, 20%, or 30% of FBF, CSS, or CDS). The experimental design was a split-split-plot with four replicates and two samples by treatment. Chemical analysis of the organic residues proved that the fertilization value of CSS was greater than the other residues and heavy metals are below the undesirable limits for the three residues. The amount of available major mineral elements in these residues is too low to satisfy the mineral nutrient needs of plants. In addition, there is a linear effect of the fertilization on plant growth. The CDS required a high dose of the fertilizer (600 mg·L–1) which may be due to the immobilization of N. The 10% proportion of FBF and CDS, combined with the other materials, was the most adequate proportion and did not reduce the growth of plants (height, aerial, and root dry matter). However, CSS can be used with a high proportion (20%) especially for Spiraea japonica `Little Princess'.
Preemergent Weed Control in Container-grown Herbaceous Perennials
Authors: Klett James E. , Hillock David , Staats David
Published: February 2019

Herbicides were applied to container-grown herbaceous perennials and evaluated on the basis of weed control, phytotoxicity, and effect on plant growth. During the 1995 season six preemergent herbicides [(in kg·ha–1) Napropamide (Devrinol 10G), 4.5 and 9.1; Isoxaben (Gallery 75DF), 1.1 and 2.3; Oxadiazon (Ronstar 2G), 4.5 and 9.1; Oxyfluorfen + Oryzalin (Rout 3G), 3.4 and 13.6; Oryzalin (Surflan AS), 2.8 and 4.5; and Trifluralin (Treflan 5G) 4.5 and 9.1, were tested on Callirhoe involucrata, Delosperma nubigenum, Dendranthemum ×morifolium `Jennifer', Festuca cinerea `Sea Urchin', and Gypsophila paniculata `Fairy's Pink'. Isoxaben (both rates) resulted in visual phytotoxicity symptoms and sometimes death to Dendranthemum. Oxadiazon (9.1 kg·ha–1) and Oxyfluorfen + Oryzalin (both rates) resulted in plant chlorosis and necrosis to Delosperma soon after herbicide application, but plants outgrew herbicide damage. Napropamide (both rates), applied to Delosperma, resulted in less dry weight when compared to some of the other herbicide treatments. Oryzalin (4.5 kg·ha–1) resulted in visual phytotoxicity and less plant dry weight to Festuca. Data analysis revealed no significant differences in Callirhoe and Gypsophila. In general, most herbicides controlled weeds effectively.
Root Distribution of Mature `Thompson Seedless' (Vitis vinifera L.) Grapevines under Aboveground Drip, Subsurface Drip, and Furrow Irrigation
Authors: Striegler R.K. , Berg G.T. , Rothberg M. , Zoldoske D.
Published: February 2019

Using subsurface drip irrigation (SDI) is increasing in California vineyards. Reports from growers indicate increased yield, increased water-use efficiency, enhanced soil pest control, and reduced canopy disease pressure for SDI when compared to aboveground drip irrigation (AGDI). However, little information is available in the literature regarding this relatively new irrigation technology for grapes and other perennial crops. A long-term trial was established to evaluate the performance of AGDI and SDI in a mature `Thompson Seedless' raisin vineyard. Portions of a furrow irrigated vineyard block were converted to AGDI and SDI before budburst in 1993. Vine performance, water use, and irrigation system performance data are being collected. As part of this trial, changes in root distribution were examined after harvest in Nov. 1995. Treatments included AGDI, SDI, and furrow irrigation. Root distribution was quantified using the trench profile method. Trenches were opened perpendicular to the row and ≈30 cm from the vine. Roots were mapped along the profile wall using a 1 × 1 m frame, which was divided into one hundred 10 × 10 cm sections. Roots were counted and categorized into four size classes: small (<2 mm), medium (2 to 5 mm), large (5 to 12 mm), and very large (>12 mm). Root distribution differed significantly for AGDI, SDI, and furrow irrigation. The type of irrigation used had the greatest impact on small roots. SDI had more small roots and total roots than AGDI or furrow irrigation. High root densities were observed near the emitter under AGDI and SDI. In addition, both drip irrigation treatments had higher root density near the soil surface than furrow irrigation. Root intrusion was not observed in the SDI treatment.
The Effect of an Alternative Cropping System on Tomato Fruit Quality
Authors: Oberly Amy , Masiunas John , Kushad Mosbah
Published: February 2019

Rye (Secale cereale) residues used in an alternative cropping system will affect nutrients, soil moisture, and soil temperatures. Each of these factors can affect tomato fruit quality. A field study was conducted comparing the effects of a rye cover crop, tomato variety, and N fertility on tomato fruit quality. In October, cereal rye was seeded at 100 kg·ha–1 to one-half of the plots. The rye was killed in mid-May by applying glyphosate at 1.1 kg·ha–1. Tomato seedlings were planted into the rye and bare-ground plots in late May. Four tomato varieties differing in cracking and soluble solids were used. There were two fertilizer regimes, no additional fertilizer, and N fertilizer applied broadcast before tomato planting, and as a sidedress based on soil tests, leaf analysis, and current recommendations. Tomato quality was evaluated based on 1) color as assessed using a Minolta chromameter, 2) cracking based on type and severity, and 3) soluble solids as determined by HPLC.
Sustainability of Organic Fertilization of Macadamia with Macadamia Husk–Manure Compost
Authors: Bittenbender H.C. , Hue N.V. , Fleming Kent , Brown Hilary
Published: February 2019

A fertilization experiment, started in 1989, evaluated the merits of macadamia husk-manure compost as fertilizer for the production of macadamia. Three fertilization treatments were compared at four sites over 4 years on the MacFarms of Hawaii Honomalino orchard. The treatments were conventional fertilization, a combination of solid and liquid mineral fertilizers annually adjusted by the orchard manager based on leaf and soil analysis; compost only as 5 tons of a macadamia husk-cattle manure compost applied annually between July and October; and compost plus supplemental mineral fertilizers deemed needed by the orchard manager based on leaf and soil analysis. In-shell nut and kernel yield and quality was not significantly different between treatments. Change in leaf nutrient values appears minimum except for slightly lower N at two sites for the compost treatment. Higher Mg was noted for the compost but not the compost plus treatments at the irrigated sites. The effect of compost on the soil nutrient levels was more distinct and may have a delayed and longer term effect. Total exchange capacity of the soil increased, as did soil pH, Ca, Mg, K, and Na. Organic matter increased only at the site with least soil. Extractable soil Fe decreased, this maybe related to the change in pH, but had no consistent effect on leaf Fe. Compost fertilization was not considered sustainable as the cost of compost and its application exceeded conventional fertilization.
A Novel Test for Evaluation of Controlled-release Fertilizers
Authors: Reddy Shiv K.
Published: February 2019

Various methods are used to evaluate the release characteristics of coated, controlled-release fertilizers. These methods include measuring the nutrients released into water or remaining in the prills or measuring the growth and nutrient content of the plants grown. Such methods do not show the release mechanism of the fertilizers. A simple test was developed that actually shows how nutrients are released from coated fertilizer prills that contain potassium. When prills of commercial products were placed in 1.5% aqueous solution of sodium tetraphenyl boron, potassium released from the prills combined with sodium tetraphenyl boron and formed a white precipitate. The precipitate patterns revealed that some new prills had large cracks or imperfect coating, thus releasing their nutrients instantly and prematurely. Over time, individual prills within the same fertilizer showed different release behaviors—from no release to release through tiny holes in the coating to release by rupture or bursting of the coating. This test is particularly useful for detecting coating defects during manufacture or subsequent damage to coating, as during incorporation of the prills into growing media. (Provisional patent application filed for this method.)
Effect of Silicon on Strawberry Plants
Authors: Wang Shiow Y. , Galletta Gene J.
Published: February 2019

The effect of silicon (Si) foliar applications on metabolic changes and powdery mildew infection in strawberry plants were determined. Silicon was used in the forms of potassium (K) and sodium (Na) salts. Foliar sprays containing 0, 250, 500, 750, and 1000 ppm of Si were applied. Strawberry plants showed no difference in response to the K or Na salts of Si during the seven weeks of experimental period. Plants treated with potassium and sodium silicate showed reduced severity of powdery mildew, increased chlorophyll content, and increased plant growth. Potassium and sodium silicate treatments also induced metabolic changes such as an increase in citric acid and malic acid levels, and a decrease in fructose, glucose, sucrose, and myoinositol content. The treated tissues also had higher ratios of (18:2 + 18:3)/18:1 in glycolipids and phospholipids and elevated amounts of membrane lipids in leaves and petioles. These results suggest that Si has beneficial effects on strawberry plants and may serve as an alternative to fungicides for controlling powdery mildew.
Compound, Surfactant, and Spray Interval Affect Black Spot Control on Rose
Authors: Pemberton H.B. , Philley G.L. , Roberson W.E.
Published: February 2019

Plants of Rosa L. `Peace' were field planted in Feb. 1995 in order to test black spot (Diplocarpon rosae Wolf) control efficacy of several compounds. Plants were protected from fungal infection by black spot with weekly sprays of chlorothalonil (Daconil) from 5 Apr. to 8 June 1995 to allow plant establishment. Spray treatments for efficacy testing were started on 23 June and ended on 1 Nov. 1995. All plants were uniformly weeded, fertilized, and irrigated as needed for the duration of the experiment. Plants were rated for defoliation and disease development on 18 July, 1 Sept., and 10 Nov. 1995. A wettable granular formulation of cyproconazole (Sentinel) controlled black spot significantly better when a surfactant, Latron B-1956, was added to the spray solution at 0.5 mL·L–1. Differences between treatments with and without surfactant were greater at lower rates vs. higher rates of cyproconazole. The most effective Sentinel rates with the surfactant were 0.13 g·L–1 applied every 14 days or 0.26 g·L–1 every 21 days. A formulated combination of chlorothalonil and thiophanate methyl (ConSyst) controlled black spot on a 7-day interval at 1.2 g·L–1, but not when applied at 1.8 g·L–1 every 14 days. Control was no better than the standard mancozeb (Dithane) treatment. Neem oil (NeemGard) was not effective on the 14-day schedule tested. Tank mixing neem oil with chlorothalonil or thiophanate methyl (Domain) did not significantly improve control. Neither myclobutanil (Systane) or a formulated combination of mancozeb and myclobutanil (RH 0611) was effective in controlling black spot.
Aphids Stimulate Peroxidase Activity but Not ACC Oxidase Activity in Watermelon Plants Inoculated with Anthracnose
Authors: Perkins-Veazie P. , Collins J.K. , Russo V. , Cartwright B.
Published: February 2019

Individually, green melon aphids (Aphis gossypi) and anthracnose (Colletotricum lagenarium) can cause serious economic damage to watermelons by reducing stands and marketable yields. Greenhouse-grown watermelon seedlings at the third true leaf stage were infected with anthracnose (106 spores/mL) and/or infested with 30 aphids per plant. At the 5th leaf stage (about 7 days after inoculation/infestation), leaf disks were harvested from plants and indicators of stress measured. Peroxidase activity increased from 0.03 to 0.28 absorbance units/mg protein-minute in leaves with anthracnose. When plants were infested with aphids after anthracnose inoculation, peroxidase activity was 0.40 absorbance units/mg protein-minute. Plants having both aphids and anthracnose had more anthracnose lesions when leaves were infested with aphids prior to anthracnose inoculation. The presence of aphids and/or anthracnose stimulated 1-aminocyclopropane-1-caroxylic acid (ACC) oxidase activity from 28 to 44 nL/g-h, indicating enhanced ethylene production. However, aphids had to be present on plants at least 5 days before ACC oxidase activity was stimulated above control levels. Aphids combined with anthracnose failed to elevate ACC oxidase levels higher than either aphids or anthracnose alone. Both peroxidase activity and ACC oxidase activity in watermelon plants increased with anthracnose infection. Thus, watermelon plants stressed by aphids and anthracnose responded differently from plants stressed individually by aphids or anthracnose.
Selenium in Water Management Wetlands in the Semi-arid West
Authors: Martens D.A. , Suarez D.L.
Published: February 2019

The discovery in 1983 of deformities, reproductive failures, and high waterfowl mortality rates at Kesterson National Wildlife Refuge, western San Joaquin Valley, Calif., due to selenium (Se) -contaminated drainage water, raised concerns that these problems may be occurring in the >600 wetlands and National Wildlife Refuges being utilized to collect irrigation drainage waste water in 17 western states. The waterfowl problems were traced to ingestion of organic Se present as Se-amino acids. Plants assimilate soluble Se into Se-amino acids and release them upon decomposition. Aerobic plant residue decomposition studies showed that 50% of the assimilated Se was mineralized to soluble Se, while the remaining organic Se persisted. This means that each growth cycle results in a steady decrease of soluble Se and an increase in organic Se levels. To test the effect of plant growth on Se accumulation, two types of evaporation ponds were evaluated, one with prolific plant growth, and the second relatively devoid of plant growth. Soil Se analysis showed that plant growth dramatically increased Se accumulation in the surface layers. Evaluation of additional Se-contaminated sites showed that Se accumulation followed an exponential function and accumulated rapidly above a 2% soil organic C content. Without plant growth, the Se remains mobile and diffuses to low concentrations in the underlying soil, suggesting that plant residue cycling is an important factor in Se accumulation and toxicity.
Wetlands of the Colorado River Delta Maintained by Agricultural Drainage Water
Authors: Glenn Edward P.
Published: February 2019

The delta of the Colorado River in Mexico historically contained 780,000 ha of riparian, marsh, and gallery forest habitat. Similar to other desert river deltas, such as the Nile and Indus, the lower delta of the Colorado River has been severely affected by the upstream diversion of water for human use. However, several large marsh areas of conservation interest still occur below the agricultural fields in Mexico. They are supported by flood water, agricultural drainage water, and municipal sewage effluent, as well as by seawater in the intertidal zone. The main anthropogenic marshes are the Rio Hardy wetland, maintained by geothermal discharge and Mexicali irrigation return flows in the western delta, and Cienega de Santa Clara, maintained by local irrigation return flows and by discharge of Wellton-Mohowk Valley drainage from the United States, imported via a 80-km canal to Mexico. These wetlands provide valuable habitat to resident and migratory waterfowl, shorebirds, mammals, and endangered species, including the Yuma Clapper Rail and the Desert Pupfish. Both wetlands are currently threatened by water management actions that do not take the wetland value of agricultural drainage into consideration. If agricultural drainage water and other available waste streams were explicitly managed to support wetlands, the Colorado River detla could potentially contain 50,000 ha or more of permanent, high-quality brackish wetlands below the agricultural fields.
To PG or Not to PG?
Authors: Huber Donald J. , Gross Ken C.
Published: February 2019

The absence of endo-α-1,4-d-galacturonanase (PG, EC 3.2.1.15) in some fruits and the molecular suppression of PG in tomato fruit have collectively provided evidence that this protein is neither required nor sufficient to achieve normal softening in fleshy fruits. On the other hand, initial claims that down-regulation of PG was without effect on tomato softening were overstated. The influence of PG on softening does appear to be minimal during the initial stages of ripening, during which time changes in the locule tissues can significantly alter texture as monitored in whole fruit. Enzymes, including pectinmethylesterases, cellulases, rhamnogalacturonanase, and glycosidases may also play pivotal roles in softening. β-galactosidases have attracted much attention as potential determinants of fruit texture; however, conclusive evidence for this role is lacking, and increased levels of β-galatosidase (and net cell wall galactosyl residue loss) have been noted in senescing vegetative and floral organs as well as in fruit. Apoplastic pH, ionic activity, and composition are likely to contribute to tissue and wholeorgan texture through weakening of polymer aggregates and/or through modulation of cell wall enzyme activity. During the latter stages of ripening and overripening, the role of PG is apparent from the persistent structural integrity of fruit transformed with PG antisense constructs. Patterns of softening and deterioration in normal tomato fruit suggest that the catalytic activity of PG in vivo is initially queued and does not parallel the accumulation of PG protein. Developmental changes in membrane permeability, physical injury, and other stress conditions can alter the apoplastic environment, releasing constraints on PG action.
Aminoethoxyvinylglycine (AVG): Past, Present, and Future
Authors: Shafer Warren E. , Clarke Gregory , Fritts Robert , Menendez Ricardo , Woolard Derek
Published: February 2019

Aminoethoxyvinylglycine (AVG) is a naturally occurring plant growth regulator that was first patented in 1973 (US patent #3,751,459). AVG has been shown to competitively inhibit ACC (1-aminocyclopropane-1-carboxylic acid) synthase (Yu et al., 1979, Arch. Biochem. Biophys. 198:280–286), which is the enzyme responsible for the conversion of S-adenosylmethionine (SAM) to ACC, the immediate precursor of ethylene in plants. Because of this unique mode of action, AVG has been tested over the years on a wide array of plant tissues. Studies on plants of horticultural interest have included cut flowers (e.g., Baker et al., 1977 HortScience 12:38–39), greenhouse crops (e.g., Saltveit and Larson, 1981, J. Amer. Soc. Hort. Sci. 106:156–159), and tree fruits (e.g., Bangerth, 1978, J. Amer. Soc. Hort. Sci. 103:401–403). AVG is currently being developed by Abbott Laboratories for use on apples (e.g., Shafer et al., 1995, Proc. 22nd Annu. PGRSA Mtg, pg 11–15). This presentation: a) briefly reviews prior literature regarding the effects of AVG on apples, b) provides an update on Abbott's commercial development program, and c) outlines some near-term research objectives for the use of AVG on apples.
Embryo Rescue Techniques to Generate Variation in Citrus Crops
Authors: Gmitter Fred G. , Grosser Jude W.
Published: February 2019

Although no longer as glamorous as it was a few decades past, the routine application of embryo rescue techniques, leading to plant recovery, is a valuable tool for citrus cultivar improvement. Embryo rescue approaches can be used to generate useful variation or to capture various kinds of spontaneous genetic variation. Embryo rescue, by in vitro culture of undeveloped, and presumably unfertilized, ovules in colchicine-supplemented media is a practical method of producing tetraploid clones, which are used then in crosses with diploids to produce seedless triploid hybrids. This same approach, i.e., in vitro culture of undeveloped ovules, is also used to recover plants from chimeric sectored fruit exhibiting economically important mutations for fruit characteristics, and for producing potentially variant somaclones. Seedlessness is an important objective for fresh citrus fruit cultivar improvement, and triploidy following 2x × 4x hybridizations is one approach being exploited for this objective. When monoembryonic diploid seed parents are crossed with tetraploid pollen parents, however, normal seed development is not usually possible. Embryos must be excised from abortive seeds fairly early in development and cultured appropriately to ensure the recovery of sufficient numbers of 3x offspring from these crosses, to increase the likelihood of identifying superior seedless hybrids. These applications will be described in some detail, and progress toward breeding objectives are highlighted.
Integrating Digital Multimedia, Computer-based Instruction, and the World Wide Web into an Introductory Biology Curriculum
Authors: Peifer R.W.
Published: February 2019

During the past 6 years, the General Biology Program at the Univ. of Minnesota has been exploring the use of computer-based multimedia to improve the quality of undergraduate instruction in large undergraduate courses. Our project has created an image library of about 3500 computer graphics, animations, and digital video sequences for lecture support, as well as the software to present and manage this image library. During the past 3 years, students have used computers for modeling, simulation, and problem-solving activities in the laboratory of our evolution and ecology undergraduate course. Most recently, we have begun to integrate the World Wide Web into our curriculum in a variety of ways. This presentation demonstrates the comprehensive way in which our Program has combined these “new” information technologies into our introductory courses. The general applicability of this approach to any discipline will be discussed.