bluuebunny/crossref_metadata_2025 huggingface dataset:
Yield Losses from Delayed Harvest of Paprika Pepper
Authors: Kahn Brian A.
Published: February 2019

Paprika pepper (Capsicum annuum L.) plants were subjected to a single, destructive harvest in either October, November, or December to determine an optimal month for once-over harvest. Studies were conducted at two locations in Oklahoma each year for 2 years. Total and marketable fruit yields were highest with October harvest dates in three of the four experiments. Marketable fruit red pigment intensity decreased between the November and December harvest dates at both locations in the second year. When the crop is established by transplanting, paprika harvest should be completed during October in the southwestern United States.
Effect of Vesicular–Arbuscular Mycorrhizal Fungi on Rooting of Sciadopitys verticillata Sieb & Zucc. Cuttings
Authors: Douds D.D. , Bécard G. , Pfeffer P.E. , Doner L.W. , Dymant T.J. , Kayser W.M.
Published: February 2019

A vesicular–arbuscular mycorrhizal fungus in a peat-based medium significantly increased survival, callus development, and rooting percentage of Sciadopitys verticillata cuttings over noninoculated cuttings. The presence of a nurse host plant for the mycorrhizal fungi to colonize in the absence of S. verticillata roots decreased survival and rooting percentage, but not callus development, relative to the fungus without the nurse host. Among plants that did produce roots, however, there were no significant differences among treatments for root number, weight, or length per cutting.
THE DYNAMICS OF HYDRAULIC LIFT IN PEACH TREE
Authors: Modise David M. , Glenn Michael D. , Ingle Morris
Published: February 2019

The split root technique was used to study water afflux in peach [Prunus persica (L.) Batsch] from wet to dry soil through root systems that bridge wet and dry soil. Peach trees conduct hydraulic lift (HL) to ameliorate water deficits in dry soil layers, under conditions of low transpirational demand. The objectives of this study were to examine the magnitude of HL in peach and to determine its effect on nutrient uptake from dry soil. In addition, the split root system was used to measure peach water uptake from soil supporting `Kentucky 31' tall fescue [Festuca arundinaceae (Schreb)] and determine the diurnal partitioning of water use from covered and bare soil treatments. A Scholander pressure bomb was used to record hourly measurements of water potentials (10 am to 4 p m), daily for a total of 14 days in 3 replicates (1 tree/rep.). Leaf stomata1 resistance was measured using a porometer, simultaneously with the water potential measurements. The CR 7 datalogger was used to record water transfer into the dry root section. 15N was applied in the 15-30 cm root zone, and the concentration in the leaves was determined using a mass spectrometer. Results obtained will be discussed in relation to objectives stated above.
EFFECTS OF AN ANTI-GIBBERELLIN GROWTH RETARDANT ON GROWTH RESPONSES OF POTATO NODAL STEM SEGMENTS CULTURED IN VITRO
Authors: Escalante Berardo , Langile Alan R.
Published: February 2019

Foliage of non-induced `Katahdin' potato plants was treated with BAS-111. Other plants were sprayed with GA3 solution and placed in an inducing chamber. All treatments were repeated the following week. After final treatment, apical, sub-apical, medial, and basal nodal stem segments were taken from each plant, surface-sterilized, and placed on MS culture media. After 3 weeks in a darkened incubator, cultures were examined. Induced plants produced 5.5 times more tubers than did non-induced segments. BAS-111 applied to non-induced plants was associated with 63% reduction in rhizome length and 3.2-fold increase in tuber number. GA treatment to induce plants resulted in improved rhizome elongation, delayed and reduced tuberization when compared with control explants. Lower nodes produced more and larger tubers than did younger tissues. Results will be discussed in light of current literature.
Handwarmers Benefit Young Citrus Trees during Freezes
Authors: Parsons Lawrence R. , Wheaton T. Adair , Yelenosky George
Published: February 2019

Handwarmers placed inside conventional insulating tree wraps increased trunk temperatures and improved tree survival under freeze conditions. Handwarmers generate heat by oxidation of Fe powder. In freeze-chamber tests with air temperature as low as –7.1C for 4 hours, wraps plus handwarmers kept trunk temperatures above freezing. Handwarmers increased minimum temperatures by 7C during a one-night freeze. Benefit of the handwarmer decreased the second night of a simulated two-night freeze but still increased minimum temperature by 1.3C. Tree survival was significantly improved by handwarmers in the freeze-chamber tests. In a field test during a mild freeze, handwarmers increased the minimum temperature by 3.5C the first night but provided no benefit the second night.
Garden Herbs as Hosts for Southern Root-knot Nematode [Meloidogyne incognita (Kofoid & White) Chitwood, race 3]
Authors: Walker Jerry T.
Published: February 2019

Twenty herb species were exposed to root-knot nematode under greenhouse conditions. The root systems were examined for root gall development and nematode reproduction as an indication of host suitability. The herbs evaluated were balm (Melissa officinalis L.), basil (Ocimum basilicum L.), catnip (Nepeta cataria L.), chamomile (Matricaria recutita L.), coriander (Coriandrum sativium L.), dill (Anethum graveolens L.), fennel (Foeniculum vulgare Mill.), hyssop (Hyssopus officinalis L.), lavender (Lavandula augustifolia Mill.), oregano (Origanum vulgare L.), peppermint (Mentha ×piperita L.), rocket-salad (Erurca vesicaria L.), rosemary (Rosmarinus officinalis L.), rue (Ruta graveolens L.), sage (Salvia officinalis L.), savory (Satureja hortensis L.), sweet marjoram (Origanum majorana L.), tansy (Tanacetum vulgare L.), thyme (Thymus vulgaris L.), and wormwood (Artemisia absinthium L.). Peppermint, oregano, and marjoram consistently were free of root galls after exposure to initial nematode populations of two or 15 eggs/cm3 of soil medium and were considered resistant. All other herb species developed root galls with accompanying egg masses, classifying them as susceptible or hypersusceptible to root-knot nematode. The highest initial nematode egg density (15 eggs/cm3) significantly decreased dry weights of 14 species. The dry weights of other species were unaffected at these infestation densities after 32- to 42-day exposure.
Heritability and Patterns of Inheritance of the Ripening Date of Apples
Authors: Tancred Stephen J. , Zeppa Aldo G. , Cooper Mark , Stringer Joanne K.
Published: February 2019

A major objective of the apple (Malus domestica Borkh.) breeding program in Stanthorpe, Australia, is to develop early ripening, high-quality cultivars. The heritability and inheritance of ripening date was investigated. Regression of offspring on midparent harvest dates and estimation of best linear unbiased predictions for parents were used to demonstrate that apple harvest date is highly heritable. Predominantly, additive genetic components of variance are responsible for the variation. Despite the existence of some specific combining ability variance and some non-normal family distributions, the best strategy for a breeder to predict the harvest date of progeny is to calculate the mean harvest date of parents.
Inheritance of Resistance to the Watermelon Strain of Papaya Ringspot Virus in the Cucumber Line TMG-1
Authors: Wai T. , Grumet R.
Published: February 2019

The inbred cucumber (Cucumis sativus L.) line TMG-1 is resistant to three potyviruses: zucchini yellow mosaic virus (ZYMV), watermelon mosaic virus (WMV), and the watermelon strain of papaya ringspot virus (PRSV-W). In this study we sought to determine the genetics of resistance to PRSV-W. TMG-1 was crossed with WI-2757, an inbred line susceptible to all three viruses. Segregation data indicated that resistance to PRSV-W was due to a single dominant gene (proposed designation, Prsv-2). Enzyme-linked immunosorbent assay (ELISA) data suggested that the mechanism of resistance to PRSV-W differs from that for ZYMV and WMV, and may be better described as tolerance. Although the plants were free of symptoms, high PRSV-W titers existed in young expanding leaves of the TMG-1 plants and the WI-2757 × TMG-1 F1 progeny.
Seed Germination of Annual Vinca Responds to Irradiation and Temperature
Authors: Blazich Frank A. , Henry Paul H. , Wise Farrell C.
Published: February 2019

Seeds of `Dawn Carpet' and `Little Bright Eye' annual vinca [Catharanthus roseus (L.) G. Don] were subjected to 32 treatments, arranged as a four × four × two factorial. For each cultivar, seeds were exposed to one of four temperatures (15, 20, 25, or 30C) during the 8-hour (day) and 16-hour (night) portions of the cycle. Within each temperature regime, half the seeds of each cultivar were irradiated for 1 hour daily, and the other half remained in constant darkness. Final germination percentages were suppressed at 15C day or night temperatures; at temperatures ≥20C, there were no significant differences between treatments. Heat input (daily degree hours) was a controlling factor in germination; different temperature cycles with equivalent numbers of daily degree hours had similar effects on germination response. There was a strong interaction between temperature and irradiation regime for both cultivars. Irradiating seeds for 1 hour/day reduced final germination percentages under cool (15C) conditions; response was not adversely affected when seeds at 15C were germinated in darkness. In a second experiment, seeds at 25C were exposed to daily photoperiods of 0, 1, 2, 4, 8, 12, or 24 hours. Germination percentages obtained in darkness and at photoperiods ≤12 hours were equivalent. Twenty-four-hour photoperiods suppressed germination compared to all other irradiation treatments.
CULTIVAR AND IBA CONCENTRATION INFLUENCE ROOTING OF BUDDLEIA
Authors: Montgomery C.C. , Behe B.K. , Eakes D.J. , Krentz T.S. , Allen V.V.
Published: February 2019

Buddleia, or butterfly bush, is a popular landscape plant because it attracts wildlife and has some heat and drought tolerance. Dirr and Heuser reported that softwood cuttings of most cultivars rooted well with a basal treatment of 3000 ppm IBA. A rooting study of 11 Buddleia cultivars was conducted in Sept. 1993 and was repeated in May 1994. Terminal softwood cuttings were treated with a quick dip of 0, 1500, 3000, 6000 ppm K-IBA. Generally, increasing rates of IBA increased root count and decreased root length. Root dry weight was minimally affected. `Royal Red', `Empire Blue', and `Lochinch' had 94% to 95% rooted cuttings. Other cultivars rooted equally better. Most cultivars produced shorter, more numerous roots in spring when a higher IBA concentration was used.
GROWTH AND ECONOMIC ASSESSMENTS OF KENAF CORE AS THE MAJOR COMPONENT IN GREENHOUSE POTTING MEDIA
Authors: Williams R. Dudley , Reichert Nancy A.
Published: February 2019

Two types of ground kenaf core (fresh and aged) were used in concentrations from 70% to 100% (v/v) in combination with peat for use as greenhouse potting media and were compared to two commercial mixes in completely randomized block designs. Greenhouse crops of Boston fern (Nephrolepis), impatiens, and pansies (Viola) were grown in the different mixes. Irrigation was conducted regularly, based primarily on the average need of all the plants. Kenaf-based media did not retain water as well as the commercial mixes. Consequently, impatiens and pansies displayed slower growth rates. However, no differences were noted for fern growth in 70% kenaf compared to commercial mixes. A second study on plants that were grouped by media type and watered as needed provided different results. Ferns grew equally well in all media, but impatiens grew best in 70% fresh kenaf. Kenaf-based media were less costly than the commercial mixes, and the cost decreased steadily as the kenaf proportion increased. The lower cost of kenaf coupled with the decreasing availability of peat should make kenaf-based media an attractive alternative to conventional greenhouse potting media.
INFLUENCE OF SEVERAL NONDEGRADABLE MULCHES AND ONE BIODEGRADABLE MULCH ON YIELD OF CRIMSON SWEET WATERMELON
Authors: Wilson Mack , Khan Victor , Stevens Clauzell
Published: February 2019

An experiment was conducted to determine the influence of several synthetic mulches and one biodegradable mulch on the yield of `Crimson Sweet' watermelons. The experimental design was a randomized block design using VisPore rowcover and various mulches. The results showed that using brown mulch resulted in a significant increase in marketable numbers of watermelons. Total yield of watermelons showed significant row cover × mulches interaction. Higher yields were observed with brown mulch and VisPore rowcover. The total number of watermelons grown with mulches was significantly greater than the control.
BREEDING FOR RESISTANCE TO PLUM LEAF SCALD
Authors: Norton J.D. , Boyhan G.E. , Tangsukkasemsan B.
Published: February 2019

Plum leaf scald (PLS) caused by the organism Xylella fastidiosa is one of the most serious diseases of plum. After X. fastidiosa was identified as the causal agent for PLS, a feral source (Starcher no. 1) was used extensively in the breeding program. Microscopic (phase contrast) examinations of vacuum extracts and petiole squashes and later ELISA were used to determine PLS infection and later were correlated with a rating index for PLS and tree longevity. Cultivars, species, and their progeny, including Prunus americana, P. angustifolia, P. cerasifera, P. munsoniana, P. salicina, P. simoni, P. bullata, and P. triflora were evaluated. Observations indicate that resistance is heritable and controlled by recessive genes. ELISA and visual observation indicated that an Auburn Univ. seedling (CD 122) was free from this disease.
DENSELY PLANTED OKRA FOR DESTRUCTIVE HARVEST
Authors: Wu Yaying , Kahn Brian A. , Solie John B.
Published: February 2019

We are developing a mechanical harvest system for okra [Abelmoschus esculentus (L.) Moench]. Our objective was to identify a high-density (HD) plant arrangement and a harvest timing that would maximize marketable fruit yield per hectare with a destructive harvest. We compared destructively harvested plants grown at spacings of (in cm) 15 × 15, 23 × 23, and 30 × 30 with hand-harvested plants grown at 90 × 23 cm. Within HD treatments, marketable fruit weight increased inconsistently as plant density increased. The 30 × 30-cm spacing was not dense enough. Branching decreased and the position of the first marketable fruit attachment moved up as plant density increased. Delaying destructive harvest until many over-mature fruit were present often did not increase marketable fruit yield and always reduced the proportion of total harvested fruit weight due to marketable fruit. Overall, percentages of marketable yield obtained by destructive harvests of HD plants were low compared to the cumulative marketable yield from control plants. However, the labor-saving potential was high. A prototype machine for harvest of HD okra has been developed, and further testing is planned.
DELIVERING HORTICULTURAL INFORMATION VIA THE INTERNET ON A MOSAIC-BASED INFORMATION SERVER
Authors: Lineberger R. Daniel , Sittler Paul , Frank Ernie , Cotner Sam
Published: February 2019

Aggie Horticulture (http://aggie-horticulture.tamu.edu) is the information server of the Texas horticulture program. Contents include information of interest to Texas A&M students and faculty, faculty members at other universities, extension programs at the state and county level, members of the horticultural industries, and the consuming public. Aggie Horticulture is a registered server on the World Wide Web that can be accessed by any networked computer on the Internet that is running “browser” software such as Mosaic or Netscape. Modem access is gained using Internet connections provided through PPP or SLIP connections. Web browsers will change dramatically the way extension provides information to horticultural industries and the consuming public. Techniques for organizing a server and the challenges associated with maintaining a server for world access are discussed.
Planting Cauliflower to a Stand with Precision Seeding
Authors: Bracy Regina P. , Parish Richard L. , Moser E.B.
Published: February 2019

Field studies were conducted in Fall 1991 and 1992 to determine 1) if cauliflower (Brassica oleracea L. Botrytis Group) could be precision-seeded to a stand without subsequent thinning and 2) the optimum seed spacing necessary to directly seed cauliflower to a stand. Seed spacings of 10, 20, and 30 cm at one seed per hill and 30 cm at two seeds per hill were evaluated for effect on yield, head weight, plant population, and early harvest percentage. As evaluated in the laboratory, seeder precision (accuracy) was good in regard to seed counts and spacing measurements at the various seed spacings. In the field, seeder precision varied in distribution patterns among seed spacings and years. Cauliflower directly seeded at one seed per hill and a 20-cm spacing produced yields and head weights similar to cauliflower seeded 10 cm apart and thinned to 30 cm—the seeding method currently used by some commercial operators.
Conditioning `Kensington' Mango with Hot Air Alleviates Hot Water Disinfestation Injuries
Authors: Jacobi Keryl , Giles Janet , MacRae Elspeth , Wegrzyn Teresa
Published: February 2019

In an effort to develop an inexpensive alternative to vapor-heat insect disinfestation of `Kensington' mango (Mangifera indica Linn.), the effect of postharvest hot water treatments (HWT) on fruit quality was determined. Fruit were given 46C HWT for 30 minutes at a fruit core temperature of 45C either 24 hours after harvest or after various conditioning treatments of 4 to 24 hours at 39 ± 1C in air. Fruit were compared to nontreated fruit after a subsequent 7 days at 22C. The HWT increased fruit softening and reduced chlorophyll fluorescence and disease incidence. The longer conditioning times produced softer fruit. Conditioning reduced damage to the fruit caused by HWT. Preconditioning for ≥8 hours resulted in <1% of fruit being damaged as shown by cavities, skin scald, and starch layer formation. The quantitatively measured higher mesocarp starch content paralleled the visible starch layer injury. Skin yellowing increased in response to HWTs that were not damaging to the fruit. Fruit ripening changes were unequally affected by HWT and by conditioning before HWT; thus, the sequence and extent of these changes must be determined to establish a reliable and useful hot water disinfestation treatment.
Mummy Berry Disease Blight Resistance in Highbush Blueberry Cultivars
Authors: Stretch A.W. , Ehlenfeldt M.K. , Brewster V.
Published: February 2019

Fifty-five highbush blueberry (Vaccinium corymbosum L.) cultivars and selections were evaluated over 2 years for their resistance to the shoot blighting phase of mummy berry disease [Monilinia vaccinii-corymbosi (Reade) Honey]. Blight incidence in 1993 ranged from 1% to 78% and differences among cultivars were significant. In 1994, infection levels were lower and ranged from 0% to 43%, again with significant differences among the entries. Several cultivars exhibited mummy berry blight resistance in both years. Ranking most resistant to less resistant were `Jersey', `Elliott', `Bluejay', `Duke', `Stanley', `Darrow', `Meader', and `Angola'. Among the cultivars consistently blightsusceptible were `Bluehaven', `Bluegold', `Northblue', `Croatan', `Northsky', `Sierra', `Harrison', `Coville', and `Murphy'. The consistent resistant reaction of certain cultivars indicates that they may be suitable as parents for introducing resistance into a breeding program. The evaluation methodology developed in these tests should be useful in screening germplasm for new sources of resistance and evaluating segregating progeny from crosses.
Progress of Apple Genetic Mapping in Europe
Authors: King Graham J.
Published: February 2019

The progress of the European Apple Genome Mapping Project will be described. Five populations segregating for a range of agronomic genes have been established in six European countries. Isozyme systems, RFLPs, RAPDs, and other PCR-based markers are being used to construct a unified genetic linkage map. Genotypic and phenotypic measurements have been precisely defined and standardized among participants. Phenotypic measurements for many agronomic traits are being replicated in different geographical locations over several years. Statistical and genetic analyses are aimed at defining components of genetic variation that account for “genes” manipulated by apple breeders. The segregation of fungal and insect resistance genes, tree habit, juvenility, budbreak, and many fruit characters has been scored. Markers have been identified linked to and flanking scab and mildew resistance genes. RAPD markers have been converted to codominant PCR-based markers for selection purposes. The JoinMap program has been extended for linkage analysis of crosses between heterozygous parents. A method for mapping QTLs in outcrossing species has been developed, together with software that is able to contend with dominant markers and missing data. Associated research is being carried out on the genetics and diversity of fungal resistance genes, fruit quality, and the socioeconomic aspects of apple production. The relational database, APPLE-STORE, has been designed and implemented for combined management of agronomic and genetic information. Synteny of linkage groups between Malus and Prunus has been established.
Molecular Markers and Mapping in Bulb Onion, A Forgotten Monocot
Authors: Havey Michael J.
Published: February 2019

Although always among the top five vegetables in value, little genetic information has been published on the bulb onion. Genetic and molecular analyses are hampered by the plant's biennial nature, severe inbreeding depression, and huge genome. Research is underway to construct a low-density genetic map of onion based on RFLPs, AFLPs, and RAPDs. Among open-pollinated populations (OPPs), levels on DNA polymorphisms were in agreement with those of other outcrossing diploid species. However, we identified little putative-allelic diversity among the OPPs (1.9 polymorphic bands per polymorphic probe–enzyme combination) supporting a bottleneck during the domestication of onion. Our segregating family is from the cross of two diverse inbreds and will be used to map quantitative trait loci conditioning phenotypically correlated production (maturity, storability, and firmness), consumer-preference (pungency, flavor, and bulb shape), and health-enhancing (anti-platelet aggregation) attributes of onion. We are also attempting to tag chromosome regions controlling relatively simply inherited traits that are difficult or expensive to characterize classically.
Principles of Biological Weed Control
Authors: Boyetchko Susan M.
Published: February 2019

Weeds continue to have a tremendous impact on crop yield losses in Canada and the United States, despite efforts to control them with chemicals. Biological control offers an additional means for reducing weed populations while reducing the reliance of the agri-food industry on chemical pesticides. Effective biological strategies that are compatible with good soil conservation practices would benefit farmers while maintaining environmental quality and a sustained production for the future. Inundative biological control of weeds with microbial agents involves the mass production and application of high concentrations of a plant pathogen to a target weed. Historically, biocontrol agents used on weeds have been foliar fungal pathogens. More recently, the soil has become a source for microorganisms, such as rhizobacteria, for development as biological control agents. Several naturally occurring rhizobacteria have weed suppressive properties, where growth and development of weeds such as downy brome, wild oats, leafy spurge, and green foxtail are significantly inhibited. Although the focus in weed biocontrol has been on the eradication of weeds, rhizobacteria may be used to improve seedling establishment of the crop by reducing the weed competition. This can be achieved through a reduction in weed growth, vigor, and reproductive capacity and improvement in the ability of the crop to compete with the weed. Current research in weed biocontrol with microorganisms and its application to weed management systems will be discussed.
Preharvest Factors Affecting Postharvest Quality of Vegetables
Authors: Weston Leslie A. , Barth M.M.
Published: February 2019

Vegetables provide a major source of essential vitamins such as ascorbic acid and beta carotene and other quality components in the human diet. Postharvest yield and quality of vegetables depend upon genetic, biotic, edaphic, chemic and other factors, as well as combinations of these factors. Successful production, quality and nutritional value of vegetables are related to both primary and secondary metabolic processes occurring during vegetable growth and development. Related research has focused upon cultivar selection, cultural practices used during production, interaction of light and temperature, and use of chemicals for growth regulation, and pest control. We will discuss the effects of genetic, pest, and soil management; crop maturity at harvest; environmental modification; and climatic conditions. Postharvest vegetable quality will be characterized in terms of vitamin content, appearance, yield, and flavor.
Monitoring Nutrient Levels during the in Vitro Tuberization of Potato
Authors: Mohamed Fouad H. , Shaaban M.M.
Published: February 2019

Macro- and micronutrient levels were monitored during the in vitro tuberization of potato (cv. Alpha) in liquid medium of MS salts and vitamins supplemented with 8% sucrose and 5 mg·liter–1 kinetin under complete darkness at 18C. Microtubers were formed in 50% of the cultured jars at day 20 and reached their full size at day 60 of culture initiation. By this time, medium N, P, and K levels had dropped by 89%, 84%, and 41%, respectively. The major drop in medium N occurred during the pre-tuberization stage, when it was taken up mostly by shoots. During tuber enlargement, the rate of Zn, Fe, and Mn removal from medium was slower than their rate of uptake by tubers. The changes in shoot and tuber Ca were very small where most of the Ca removed from medium was diverted into the roots.
Experimental Evaluation of an Environmental Education Program and Its Impact on Knowledge and Attitudes of Texas Secondary School Students
Authors: Bradley Jennifer C. , Zajicek J.M. , Townsend C.D. , Briers G.E.
Published: February 2019

The objectives of this research project were to: 1) Develop an environmental science curriculum that was heavily activity-based, 2) evaluate the curriculum for usefulness as a teaching tool, and 3) test student knowledge and attitude changes towards the environment resulting from exposure to this 10-day curriculum unit. The curriculum developed entitled Environmental Technology—”Natural State of the Environment” was designed to provide an introduction to biological processes and basic principles of ecology, and to set the foundation for additional environmental studies. The curriculum was sent to 31 high schools in Texas and tested on 1500 students. Students participating in this study were administered a pretest prior to participation in the environmental science curriculum and an identical post-test after its completion. The questionnaire included an attitude inventory and knowledge section in addition to a biographical information section. Results examine the relationship between environmental knowledge and environmental attitudes, determine the attitude and knowledge changes from before until after the instructional unit, and focus on the importance and need for environmental education programs.
Need for Systemic Change in Undergraduate Education
Authors: Singha Suman , Kunkel Harry O.
Published: February 2019

Changes in the environment, in technology, and in societal needs will result in a change in the expectations from our graduates. Meeting these expectations will require a systemic change in undergraduate education in horticulture. While we do an excellent job in training students, we are not as effective in educating them. Our students must develop critical thinking skills and become adept at solving problems utilizing a multidisciplinary integrated approach rather than in a reductive manner. Achieving these skills is essential if our graduates are to be successful in the rapidly changing job market. Implementing curricular change requires faculty ownership as well as administrative support and an appropriate rewards and recognition system. These and other principles from the USDA-funded project on Theoretical Bases for Systemic Change in Higher Education in Agriculture will be discussed.
Mechanical Harvesting of Peppers
Authors: Marshall Dale E.
Published: February 2019

For nearly 30 years, more than 75 different groups: producers, entrepreneurs, engineers, processors, consultants, state or federal researchers, or manufacturers have constructed over 195 harvesters attempting to mechanize the harvest of Capsicum peppers. Countries testing experimental harvesters include: Bulgaria, Hungary, Israel, Italy, Spain, the United States, and the former Soviet Union. Over 25 principles have been tested. In 1980, there were 10 different university, state, or federal research agencies experimenting with pepper harvest mechanization. However, in 1990, there were no active mechanization projects. At least 13 patents have been identified that have been issued on pepper harvesters and 65 patents on harvesting elements or principles for other crops that have been tested or might be used to harvest peppers. Interest in mechanization has resumed in the United States and a number of commercial harvesters are available. Harvester usage is expected to increase significantly by the year 2000.
Watermelon Yield as Affected by Plant Density and Spatial Arrangement
Authors: Roberts Warren , Duthie Jim
Published: February 2019

Watermelons are grown at many different row widths and in-row spacings, but an ideal plant density has not been established. Experiments were conducted at one location in 1993 and at two locations in 1994 in southeastern Oklahoma. Effects of plant density and spatial arrangement on `Allsweet' and `Sangria', two standard-sized watermelons, were evaluated. Beds 0.3 m wide were formed on 0.91-, 1.83-, 2.74-, and 3.66-m centers. Various in-row spacings that ranged from 0.30 to 2.44 m were established at each row width. This resulted in various spatial arrangements of plants with densities of 1500, 3000, 6000, and 12,000 plants/ha. With 1500 and 3000 plants/ha, about one melon was harvested from each plant, and less than one melon was harvested from each plant when the density reached 12,000 plants/ha. Yield (weight/ha) increased with plant density and reached a maximum at 12,000 plants/ha. Isometric spatial arrangements did not produce greater yields than did the more-rectangular arrangement. Weight per melon decreased with increasing plant densities in two experiments, but the decrease was small relative to the increased number of melons/ha.
Maximum Improvement of Cucumber Yield is Expected if Planted Shortly Following Nematode-resistant Tomatoes in Soils Susceptible to Nematode Buildup
Authors: Hanna H.Y. , Kirkpatrick T.L. , Colyer P.D.
Published: February 2019

Our previous studies have indicated that improving cucumber yield in nematode-infested soil is feasible without chemical control if planted after nematode-resistant tomatoes. The current study was conducted to determine the length of time this beneficial effect might last. Results indicate that planting cucumbers shortly after the last harvest of nematode-resistant tomatoes (July) significantly increased the premium and marketable yields. Nematode injury to the cucumber root system was extremely low. Cucumbers planted 1 month later (August) also produced higher premium and marketable yields and sustained less injury to the root system. However, yield improvements and root injury reduction of cucumbers planted 1 month later were not of the same magnitude noticed of cucumber planted shortly after the termination of the tomato crop. These results may indicate a tendency of a gradual nematode buildup in the soil previously planted with the nematode-resistant tomatoes.
Nitrogen and Potassium Application Scheduling for Drip-irrigated Tomatoes
Authors: Locascio S.J. , Rhoades F.M. , Olson S.M. , Hochmuth G.J. , Hanlon E.A.
Published: February 2019

Tomato (Lycopersicon esculentum Mill.) was grown with drip irrigation on a fine sand and on a fine sandy loam to evaluate the effect of N and K time of application on yield. On the sandy soil, 196–112 kg of N–K/ha was applied with 0%, 40%, or 100% preplant with 100% or 60% applied in six or 12 equal or in 12-week variable applications. Marketable fruit yields were lowest with 100% preplant, intermediate with 100% drip-applied, and highest with 40% preplant with 60% drip-applied. With 100% drip-applied, yields were highest with 12 even than with six even weekly applications or with 12 variable N and K applications. With the 40% preplant, timing of application had little effect on yield. On the sandy loam soil in 1993, where only N was applied (196 kg·ha–1), yields were highest with 100% preplant, intermediate with 40% preplant and 60% drip-applied, and lowest with all N drip-applied. In 1994, when excessive rains occurred, yields were similar with all preplant and with split-N applications.
Comparison of Specific Electrode Techniques for Measuring Bell Pepper Petiole Sap Nitrate Concentration
Authors: Taber H.G. , Cox D.F. , Smith B.C. , Klock K.A.
Published: February 2019

Sap nitrate was determined with the ion-selective electrodes, HACH combination nitrate electrode, and the CARDY nitrate meter on pepper petioles over five sample dates (n = 160). The electrode values were compared to the Cd reduction method performed on a Lachat automated ion analyzer with flow injection analysis. Thirty petioles were collected from plots of each of several N rate studies and the sap expressed by a hand-held garlic press. Correlation among the techniques were similar (r > 0.9), but the CARDY meter constantly read 100 to 175 ppm higher than the HACH. Across all dates the standard deviation of the difference, compared with the Cd reduction, for the HACH = 16 ppm, while for the CARDY it was 50. While the CARDY meter is easier to use and has fewer steps, the HACH electrode values were closer to the true readings and less erratic. One must use care when interpreting nitrate sufficiency value ranges with different quick-test techniques.
The Influence of Plug Storage Time, Greenhouse Temperature, and Photoperiodic Manipulations on the Plant Habit and Flowering of Several Perennial Species
Authors: Armitage Allen M.
Published: February 2019

Plugs of Arabis `Spring Cham', Cerastium `Columnae', Salvia `Blue Queen', and Saxifraga `Purple Robe' (128 plugs/tray) were cooled at 2 to 3C for 0, 4, or 8 weeks. Plugs were potted in 10-cm containers and placed in warm (20C day, 17C night) or cool (10C day, 8C night) and provided with various long- and short-day combinations. In general, all taxa flowered more rapidly in the warm house, but were not significantly taller. Arabis showed no response to cooling or photoperiodic treatments, but Cerastium and Saxifraga had significantly longer internodes when subjected to increasing number of LD cycles. Plants of Salvia and Cerastium also flowered more rapidly when subjected to increasing cycles of LD, but height of Salvia and Arabis was reduced when LD were followed by SD. Other species of perennials will also be discussed.
Effects of Fertilizers, Salinity, and Medium on Growth of Phalaenopsis Orchid
Authors: Wang Yin-Tung
Published: February 2019

Seedling Phalaenopsis (P. Taisuco Eagle × P. Taisuco Rose) plants with an 8- to 10-cm leaf span were grown in 10-cm pots filled with a medium consisting of 70% fine fir bark and 30% peatmoss (by volume). Plants were given (in N–P2O5–K2O) 10–30–20, 15–10–30, 15–20–25, 20–5–19, 20–10–20, or 20–20–20 fertilizers at the 100 or 200 mg N/liter rate. Pots were leached with water following every two fertigations. After 7 months, leaf span, leaf size, total leaf area, and fresh weight were not affected by fertilizer type. The differences in leaf numbers were small. The higher rate of fertilizer resulted in plants with wider leaf span (32.8 vs. 28.5 cm), more (5.5 vs. 4.8), larger (103 vs. 89 cm2) leaves, and greater total leaf area (355 vs. 275 cm2) than did the lower rate. In another experiment, similar plants with a leaf span of 15 to 18 cm were grown in 10-cm pots with 100% fine fir bark or a mixture of 80% fine fir bark and 20% peatmoss. They were fertigated with water having an EC - 0.05, 0.40, 0.75, 1.10, or 1.40 dS·m–1 containing 1 g·liter–1 20–20–20 fertilizer three times and then drenched with their respective water containing 0.6 g·liter–1 Ca NO3)2·4H2O. After 11 months, water salinity did not affect the date of spiking. Plants receiving water with EC = 1.10 dS·m–1 had more leaves and spikes than other treatments. Plants in the bark/peatmoss mix began spiking earlier, had more leaves (6.7 vs. 5.7), and more inflorescences (1.9 vs. 1.5) than those in 100% bark. There was no salinity x medium interaction in all the parameters recorded.
Bloom Thinning of Peach, Nectarine, and Apricot
Authors: Williams Max
Published: February 2019

Chemicals being tested for bloom thinning of apples are effective for bloom thinning of stone fruit. Sulfcarbamide (Wilthin) and Endothall applied to peaches, nectarines, and apricots at 90% of bloom open reduced fruit set by 50%. Fruit size and quality of crop were improved. Slight phytotoxicity occurred on leaves and twigs, but no injury occurred on fruit. Two years of data will be presented and comparisons will be made with other new thinning agents.
Growth Response of Apple Fruit to NAA and Accel: Effect of Intraspur Competition and Position on a Spur
Authors: Black Brent L. , Bukovac Martin J. , Stopar Matej
Published: February 2019

Apple fruit size is influenced by position on the spur, and location and number of competing fruits. King fruit appear to have the greatest potential to size and grow best in the absence of intraspur fruit competition (ISFC). Accel (A) and NAA (N), commercial thinning chemicals, influence fruit size beyond their effects on crop load. A 2-year study was conducted to determine the effect of ISFC and position (king, K, or lateral, L) on fruit growth in response to A and N. Branches from `Redchief Delicious' were thinned, after petal fall, to one K, one L, one K + one L, or two L fruits per spur. Whole-tree treatments of N (15 mg·liter–1), A (50 mg·liter–1, 1993; 25 mg·liter–1), and a combination (N+A) were applied at 10-mm king fruit diameter. A nontreated control was included. In 1993, N and N+A reduced fruit size only with ISFC, while A increased fruit size in the absence of ISFC. In 1994, A had no effect, but N and N+A reduced fruit growth with ISFC. In both seasons, A and N decreased the frequency of spurs bearing multiple fruit, while N+A dramatically increased number of spurs with multiple fruits (branch survey).
Electronic Sensing of Melon Ripeness Based on Volatile Gas Emissions
Authors: Hetzroni Amots , Charles Denys J. , Simon James E.
Published: February 2019

A nondestructive electronic sensory system (electronic sniffer) that responds to volatile gases emitted by fruit during ripening was developed. It is based upon a single semi-conductor gas sensor placed within a rigid plastic cup equipped with a gas inlet to flush the head between samples. This gas sensor reacts with the range of reductive gases such as the aromatic volatiles that are naturally emitted by the ripening melon fruit. The sensor cup is placed on the exterior of the fruit and the change in electrical conductivity is recorded. In 1994, we examined the electronic sniffer as a tool to nondestructively determine ripeness in `Superstar', `Mission', and `Makdimon' melons. Fruits were manually classified into five ripeness stages based on external appearance and slip stage. Melons were first sampled nondestructively for color, weight, size, and slip stage, and then subjected to the electronic sniffer. Then, fruit volatiles, flesh firmness, and total soluble solids were measured. The electronic sniffer was able to accurately classify melons into three ripeness classes: unripe, half-ripe, and ripe for `Superstar' and `Mission'. The sniffer was only able to separate ripe from over-ripe in `Makdimon', which is known to become over-ripe and deteriorate rapidly. Using the sniffer as a tool to nondestructively measure ripeness and its potential application in fruit quality will be discussed.
Potential of Proteinase Inhibitors for Insect Pest Control: The Case of the Colorado Potato Beetle
Authors: Overney S. , Le V.Q. , Visal S. , Yelle S.
Published: February 2019

Bioengineering economically important plants with proteinase inhibitors (PIs) is a promising method for the control of insect pests. In the case of the Colorado potato beetle (CPB; Leptinotarsa decemlineata Say), the major insect pest of potato fields, 80% of the digestive proteases are of cysteine type. We showed that 60% of these cysteine proteases are inhibited by oryzacystatins (OCs). The use of these cysteine protease inhibitor genes therefore appears of great interest for the production of Coleoptera-resistant transgenic plants of potato. Complementary studies of biochemical in vitro assays showed an apparent absence of direct interference between OCs and potato proteases. The high regeneration efficiency of the genetically transformed plants with OC gene and the “normal” phenotypical growth of the resulting transgenic potato plants suggested that these foreign genes do not interact with important physiological processes in the potato plants. In vivo assays of PIs against CPB at various developmental stages suggest the significant potential of OCs as an effective way to control CPB populations and crop damage.
New Strawberry Selections from the Quebec Breeding Program
Authors: Khanizadeh Shahrokh , Buszard Deborah J.
Published: February 2019

Promising 1989 strawberry selections from the Agriculture Canada/McGill Univ. breeding program have been evaluated since 1990 at three different sites in Quebec. `Kent', `Glooscap', `Honeoye', `Bounty', and `Veestar' were used for comparison. Yield, average fruit weight at each harvest, firmness, color, taste, and other fruit characteristics were evaluated. SJ89288-2 had the highest yield with large fruit. SJ89700-1 and SJ89264-6 produced similar yield to `Kent' and `Glooscap', with firm and large fruit. SJ89700-1 had bright red skin color and SJ89264-6 had bright pale red color. Both are suitable from fresh-market and pick-your-own (PYO). SJ8976-1, another selection, had a firm, large, bright pale red fruit. All four selections have good shelf life quality and will be tested at four sites during 1993–95.
Anthracnose Fruit-rot Resistance in Highbush Blueberry Cultivars
Authors: Ehlenfeldt Mark K. , Stretch Allan W. , Brewster Vickie
Published: February 2019

Thirty-three Vaccinium corymbosum selections and cultivars were artificially inoculated with spores of Colletotrichum gloeosporioides in the green fruit stage. Fruit was harvested when ripe and incubated under high-humidity conditions for 1 week, before evaluation. A wide range of susceptibility to anthracnose fruit-rot was found, ranging from 8% to 85%. Among the most-resistant cultivars were: `Elliott' (8%), `Murphy' (8.3%), `Stanley' (13%), and `Weymouth' (16.9%). Among the most-susceptible cultivars were: `Bluetta' (85%), `Spartan' (82.7%), `June' (69.9%), and `Northblue' (69.5%). Uninoculated checks had a maximum of 6% infection.
Metrical Analysis of a Semi-seedless Rabbiteye Blueberry Selection
Authors: Hall Melvin R. , Ehlenfeldt Mark K.
Published: February 2019

A rabbiteye blueberry selection, T-285, appears parthenocarpic when grown in the greenhouse and sparsely seeded when grown in the field. This semi-seedless character was analyzed to determine the nature and degree of its cross- and self-fertility in comparison to its parents, `Tifblue' and `Delite'. Ovule numbers from T-286 were similar to those of `Tifblue', but lower than those of `Delite'. Seed numbers of open-pollinated `Tifblue' and T-286 were similar, and lower than `Delite', but T-286 was notable in having fruit 60% larger than `Tifblue' and 10% larger than `Delite'. Both `Tifblue' and T-286 had a tendency to produce some open-pollinated fruit with few or no seed present. None of the selections produced significant amounts of fruit when self-pollinated. When cross-pollinated, all selections set more seed, but this was less pronounced with T-286 than with either of its parents.
Selenium Affects Sulfur Uptake and Metabolism in Onions (Allium cepa L.)
Authors: Kopsell Dean A. , Randle William R.
Published: February 2019

The affects of selenium (Se) on sulfur (S) uptake and metabolism were evaluated in `Granex 33' onions. Plants were grown in a half-strength Hoagland's solution and modified with increasing Se fertility. Selenium was added as sodium selenate. During growth, plants were sampled biweekly and divided into root, bulb, and foliar tissue. Tissues were dried and ground for total S, and wet-ashed for total Se (GFAA). Selenium increased S uptake by onions. As Se increased in concentration, S utilization first increased then decreased in a quadratic trend.
Vegetative Flush Development and Leaf Area Contribution to Citrus Canopies
Authors: Albrigo L. Gene
Published: February 2019

The recent infestation of Florida citrus by the Asian citrus leafminer required that more information be obtained about the time interval for a flush to expand and the leaf area contributed by flushes in seasons when leafminer populations are likely to increase and cause leaf area loss. Time for leaf and shoot expansion was determined for spring and summer flush. Leaf area contribution from previous-year and current flushes was determined by seasonal tagging and measuring leaf area for flush in frame areas of 1/4 m2 surface projected to the center of the tree. Flush of 1/3 m length required 30 days to expand from first leaf feathers to full expansion. Summer flush in 1994 was 40% to 45% of total leaf area. Spring and previous year's flush averaged 20% each. Fall flush contributed 5% to 12% to leaf area, more on young, low-bearing trees. Summer flush resulted in more canopy leaf area and previous year's flushes less leaf area than expected by the end of the growing season.
Effects of Elevated CO2 on Sorbitol Partitioning in Sink and Source Apple Leaves
Authors: Pan Qi-yuan , Quebedeaux Bruno
Published: February 2019

Apple and many other Rosaceae plants translocate sucrose as well as sorbitol. How photosynthates are partitioned between sorbitol and sucrose in the Rosaceae is not understood. This study was designed to examine the effects of elevated air CO2 on partitioning of sorbitol and other soluble sugars in sink and source apple leaves. Young `Gala' apple plants were exposed to the ambient air and 700, 1000, and 1600 μl·liter–1 of CO2 for 8 days under a light intensity of 928 μmol·m–2·s–1 with a 14-h day/10-h night cycle. Sorbitol, sucrose, glucose, and fructose concentration in sink and source leaves were determined by HPLC analysis. In source leaves, sorbitol was significantly increased, while sucrose was decreased as the air CO2 was elevated from 400 to 1600 μl·liter–1. The sorbitol/sucrose ratio varied from 1.31 in air and 2.26 at 1600 μl·liter–1 of CO2. In sink leaves, sorbitol concentration did not vary across the four CO2 levels; however, sucrose was higher at the three super-atmospheric CO2 levels. Our results suggest that increased photosynthesis via elevated CO2 favors photosynthate partitioning into sorbitol rather than sucrose. A mechanism for regulating this partitioning will be discussed.