bluuebunny/crossref_metadata_2025 huggingface dataset:
414 Biotechnology in Agriculture: A Multimedia Approach to Problem-based Learning and Distance Learning
Authors: Kitto S.L. , Griffiths L. , Pesek J. , Mackenzie E. , Bauer K.
Published: February 2019

In 1997, we added distance students to a traditional, classroom-taught biotechnology course. To reach distance students, we used a multimedia approach: lectures via videotapes and problem-based learning exercises (PBL) via the Internet. About a third of the course was taught using PBL. The major challenge of the course was to teach the PBL segments to distance and traditional students working in groups. We explored ways to use multimedia technology that would allow distance students to participate in the PBL segments of the course. To assess the effectiveness of the methods used in this project, we compared the distance students with traditional students using measures of perceived and actual knowledge of biotechnology. The student–student interactive PBL segments were challenging because the traditional students were working in “real time” and the distance students were working in “distance time.” Distance students did as well as in the course as traditional students; however, management of groups composed of distance and traditional students was challenging. PBL could probably be used more effectively and successfully with student groups composed solely of distance students.
434 Environmental Risk Assessment—A Nutrient Management Planning Strategy For Nursery and Greenhouse Systems
Authors: Lea-Cox John D.
Published: February 2019

In 1998, the state of Maryland adopted some of the toughest nutrient management planning regulations in the Nation, requiring virtually all agricultural operations plan and implement nitrogen and phosphorus-based management plans by Dec. 2002. The nursery and greenhouse industry is faced with a far more complicated nutrient management planning process than traditional agronomic planning scenarios. Factors include a large number (>500) of plant species, various fertilization and irrigation strategies, with crop cycles ranging from 6 weeks (bedding plants) to upwards of 15 years for some tree species in field production, often with a lack of knowledge of specific nutrient uptake rates and utilization. In addition, unique infrastructural and site characteristics that contribute to water and nutrient runoff from each nursery contribute to a multitude of variables that should be considered in the planning process. The challenge was to identify a simple, effective process for nutrient management planning that would a) provide an accurate assessment of nutrient loss potential from this wide variety of production scenarios, b) identify those specific factors that contribute most to nutrient leaching and runoff, and c) provide a mechanism to economically assess the various risk management (mitigation) scenarios. This risk assessment process provides information on a number of fixed (site) and dynamic (management) variables for soils/substrates, irrigation and fertilization practices, together with any surface water management systems (e.g. containment ponds, riparian buffers). When all the risk factors for a nursery are evaluated and scored, the complete picture of risk assessment then emerges. By identifying higher risk factors and evaluating different risk management options, the grower and/or nutrient management planner can then choose economic alternatives to reduce the potential for nutrient runoff.
445 Production of Castilleja as a Greenhouse Crop in Wyoming
Authors: Panter Karen L.
Published: February 2019

The objective of this study was to determine if hemiparasitic Castilleja (Indian Paintbrush) could be successfully sown and grown in the same containers with each of three host plants. Perennial Castilleja linariifolia, Wyoming's state flower, was sown in combination with either Helianthus annuus `Pacino', Lupinus `Russell Mix', or Artemisia frigida. Seeds were sown 7 Oct. 1999 in 128-cell plug trays. Trays were then placed on a mist propagation bench at 21 °C until emergence of any plant species was evident. Artemisia emerged 12 Oct.; Lupinus and Helianthus emerged 13 Oct. Plug trays were then transferred to a greenhouse at 13 °C night/21 °C day temperatures under natural light conditions. Plugs were transplanted into 11.4-cm-diameter containers on the following dates: C. linariifolia/Helianthus–12 Nov.; C. linariifolia/Lupinus–18 Nov.; and C. linariifolia/Artemisia–2 Dec. C. linariifolia emerged, after transplanting, on 16 Dec. All three combinations were successfully produced in the greenhouse.
450 Effects of Transplant Production and Handling Practices on Processing Tomato Production
Authors: Hartz T.K. , Miyao E.M. , Giannini C.
Published: February 2019

Three field trials were conducted in central California in 1999 to assess the effects of transplant production and handling practices on yield, crop maturity, and fruit quality of processing tomato (Lycopersicon esculentum Mill.). For each trial, transplants of `Halley' tomato were obtained from a variety of commercial greenhouse transplant growers and subjected to various conditioning treatments during the week prior to planting. These treatments included N and/or P fertilization, varying temperature exposure or degree of water stress, or storage in the dark for 2 days before transplanting to simulate shipment from greenhouse to field. Nine transplant treatments (combinations of transplant source and conditioning treatment) were evaluated in each trial, with five 30 m long single-row plots per treatment arranged in a randomized complete-block design. Plots were mechanically harvested. Despite large differences among treatments in initial transplant characteristics (plant height, root cell volume, macronutrient content), there were no significant treatment differences in fruit yield in two trials; in the third trial, one treatment had significantly lower yield than the highest yielding treatment. In no trial were treatment differences in crop maturity (percent green fruit) or fruit quality (soluble solids content or juice color) significant. Across trials, the only transplant characteristic positively correlated with relative fruit yield (treatment yield/mean yield of that trial) was shoot P concentration, which varied among treatments from 1.3 to 11.7 g·kg–1.
458 Professional Development for Graduate Students: A Course Offering at the University of Florida
Authors: Skelly S.M. , Kohlleppel T.C. , Kane M.E. , Bradley J.C.
Published: February 2019

In Spring 1999, the Environmental Horticulture Graduate Student Association (EHGSA) at the Univ. of Florida was given the opportunity to develop a professional development course, for credit, for graduate students. Members of the EHGSA determined that there was a need for seminars on topics such as curriculum vitae development, interview techniques, effective presentations, successful teaching, and many more topics pertinent to the graduate student as a future professional both inside and outside of academia. As a group, the EHGSA determined the seminar topics, found speakers to present the information and organized the course for the Fall 1999 semester. The rationale for creating this course, its development, topic selection, and student reviews will be presented.
469 Multi-faceted Approaches to Genetic Engineering of Petunia × hybrida for Delayed Leaf Senescence
Authors: Clark David G. , Dervinis Chris , Cuquel Francine , Klee Harry , Barrett Jim , Nell Terril
Published: February 2019

In an effort to modify and study leaf senescence, we have produced several different transgenic petunia lines with altered leaf senescence phenotypes. Using two promoters from senescence-associated genes (sag12 & sag13) fused to the isopentenyl transferase (IPT) gene, which catalyzes the rate-limiting step of cytokinin production, we have produced transgenic petunia plants with delayed lower leaf senescence. We have observed that apparent “leaky” expression of IPT gives rise to plants with other morphological alterations such as increased branching habit and decreased root formation. Plants with delayed leaf senescence phenotypes were selected and bred to produce progeny that were evaluated in greenhouse experiments. Breeding characteristics, horticultural performance and reproduction of these plants will be discussed in terms of potential commercial benefits and limitations. Using the sag12 promoter to drive expression of the knotted (KN1) gene, we have also been able to engineer petunia plants with delayed lower leaf senescence. Initial progeny evaluations of sag12-KN1 petunias will also be discussed.
472 Effect of Pruning on Secondary Bloom in `Bartlett' Pear
Authors: Moran Renae E. , Southwick Stephen M.
Published: February 2019

Secondary bloom provides fireblight infection sites in pears (Pyrus communis L.) growing in the western U.S. Five types of secondary bloom occur in `Bartlett', and one of these, Type V, occurs mainly as a result of pruning. We examined the effect of pruning dates (Feb. to Sept. 1999), shoot age ranging from 1 to 4 years old, and type of pruning cut (i.e., heading, stubbing, or thinning) on Type V secondary bloom. Pruning date was a significant factor determining whether Type V would occur. There was a greater chance for Type V to occur from pruning in February or March than for pruning from May through September. There was an increase in Type V with increase in shoot age when pruning 11 Feb., 17 Mar., 14 May, or 11 Aug. There was no shoot age effect when pruning 18 June or 30 Sept. Type of pruning cut affected the number of Type V that occurred when pruning 14 May, 18 June, or 11 Aug., but the effect of type of pruning cut was inconsistent between these dates. There was no effect of type of pruning cut when pruning 11 Feb., 17 Mar., or 30 Sept. These results indicate that summer or postharvest pruning may reduce the number of Type V secondary bloom, particularly on shoots older than one year. This information can be used to develop a pruning strategy that reduces the number of Type V secondary bloom and potentially the number of fireblight infection sites.
488 The Effect of Population Densities, Vine Training Methods, and Harvest Duration on Shoot Yield of Fluted Pumpkin (Telfairia occidentalis)
Authors: Olufolaji A.O. , Makinde Margaret J. , Akinfasoye J.A.
Published: February 2019

Nursery-sown seedlings of Telfairia occidentalis were transplanted to the field plots of the National Horticultural Research Inst. in May 1998 and 1999. The treatment involved sowing using three population densities of 75,000; 45,000, and 30,000 plants/ha, which translates to 50 × 50-cm; 100 × 50-cm and 100 × 100-cm spacing. The second experiment involved sowing at 1 × 1-m spacing and one, two, four, zero, eight, and 12 harvests with staking vs. non-staking of vine methods. The studies were of a completely randomized block design using four replications. The results showed that most of the vegetation plant characters measured in the study on one hand were favored by 75,000 plants/ha, while, on the other hand, the highest fruit production occurred in 45,000 plants/ha. Harvesting eight to 12 times gave similar, but significantly higher,vegetative yield than the other lower frequencies. Nevertheless, fruit production in number and weight was superior in plants given the minimum (one or two) pruning. There were no significant differences in the measured plant characters of plants that were staked compared to the non-staked plants. However, fruit yield was better in staked than non-staked plants.
494 Evaluation of Interior Performance of Six Cultivars of Aglaonema and Dieffenbachia
Authors: Chen Jianjun , McConnell Dennis B. , Pennisi Svoboda V. , Robinson Cynthia A. , Caldwell Russell D.
Published: February 2019

Tissue culture plugs of Aglaonema `Cory', `Maria', and `Silver Queen' and Dieffenbachia `Panther', `Snowflake', and `Sport Lynn' were potted singly in 15-cm pots and grown in a shaded greenhouse under a photosynthetic irradiance (PI) of 100 mmol·m–2·s–1. Eight months after potting, 27 plants of each cultivar were placed in nine interior evaluation rooms under three different PI levels (three rooms per level): 4, 8, and 16 mmol·m–2·s–1. In addition, three plants of each cultivar were maintained in the original greenhouse for the duration of the experiment. Number of leaves, plant height and width were monitored monthly. Recently matured leaves were removed at 3-month intervals for 9 months for determination of fresh and dry weight, leaf area, and percentage leaf variegation. Variegated leaf area was assessed using digitized leaf images. Interior PI levels affected growth parameters, but the degree of response was cultivar-dependent. Smallest leaves developed on plants grown under 4 mmol·m–2·s–1 and largest leaves developed under 16 mmol·m–2·s–1. Leaf area of Dieffenbachia `Sport Lynn' showed the greatest response and Aglaonema `Maria' the least response to PI levels. Percentage leaf variegation of Dieffenbachia `Snowflake' was least affected and Dieffenbachia `Sport Lynn' was most affected by PI levels. Fresh leaf weight of unit area decreased as PI levels decreased from 16 to 4 mmol·m–2·s–1, however, the decrease in unit area was most pronounced in cultivars that maintained the highest quality ratings. Based on the results of this study, Aglaonema `Maria' and Dieffenbachia `Snowflake' had the most satisfactory interior performance within their respective genera.
503 Effect of Source and Timing of Potassium Fertilizer on `Empire' Apple Tree Growth, Yield, and Fruit Quality
Authors: Robinson Terence L. , Stiles Warren
Published: February 2019

A field experiment was established in 1993 in a 3-year-old `Empire'/M.9 apple orchard. An incomplete factorial treatment design compared nitrogen only fertilization with nitrogen plus potassium fertilizer applied either on the ground with and without trickle irrigation or through the trickle irrigation system. Timing of potassium fertigation treatments compared season-long K fertigation to early season or late-season K fertigation. Results of main effects showed that K fertilization reduced trunk cross-sectional area increase, but increased yield, fruit size, and fruit red color. There was no benefit of fertigation compared to ground application of fertilizers plus trickle irrigation. There was no effect of source of K fertilizer (KCl vs KNO3) on tree growth, yield, fruit size, or color. Time of K fertigation showed that late-season K fertigation resulted in greater trunk cross-sectional area increase compared to early season fertigation or season-long fertigation. Fruit size was greatest when K fertigation was done in the early season. There was no effect of time of fertigation on yield or fruit red color. Potassium fertilization increased leaf K levels and reduced leaf Mg levels. Time of fertigation did not affect leaf K levels, but early season fertigation resulted in higher leaf N levels.
506 Air Temperature, Humidity, Leaf Age, and Solution pH Affect Penetration of Urea Through Citrus Leaf Cuticles
Authors: Orbovic Vladimir , Achor Diann , Petracek Peter , Syvertsen James P.
Published: February 2019

We examined the effects of air temperature, relative humidity (RH), leaf age, and solution pH on penetration of urea through isolated cuticles of citrus leaves. Intact cuticles were obtained from adaxial surfaces of different aged grapefruit leaves. A finite dose diffusion system was used to follow movement of 14C-labeled-urea from solution droplets across cuticles throughout a 4-day period. The rate of urea penetration increased as temperature increased from 19 °C to 28 °C, but penetration was not further increased at 38 °C. Increasing RH increased droplet drying time and urea penetration at both 28 °C and 38 °C. Cuticle thickness, weight per area, and the contact angle of urea solution droplets increased as leaves aged. Cuticular permeability to urea decreased as leaf age increased from 3 weeks to 7 weeks, but permeability increased in cuticles from leaves older than 9 weeks. Contact angles decreased with increased urea solution concentration on six 7-week-old leaf surfaces, but solution concentration had no effect on contact angle on cuticles from younger and older leaves. Reducing pH of urea solution from pH 8 to pH 4 accelerated the loss of urea from breakdown, possibly due to hydrolysis.
508 Studies on the Effects of Zinc Supply on Growth, Development, and Nutrient Uptake of Pecan Seedlings from Different Seedstocks
Authors: Kim Tehryung , Mills Harry A. , Wetzstein Hazel Y.
Published: February 2019

Zinc deficiency is a nutrient disorder that is observed in pecan production areas. In the field it is characterized by a rosette shoot habit and interveinal leaf chlorosis. Up to now, the induction of zinc deficiency has not been accomplishable in the field or greenhouse. Thus any critical evaluations of effects of zinc nutrition on tree growth and development have been lacking. A hydroponic culture system was developed where zinc deficiency was induced. Seedstocks collected from `Stuart', `Curtis', and `Wichita' trees were grown with and without zinc supply. Biomass, leaf area, node number, and visual symptoms were assessed. Foliar deficiency symptoms were rated 4 and structural evaluations were conducted using light and electron microscopy. Significant differences in visual symptoms were observed between treatments and among cultivars. Leaf area significantly decreased in `Stuart' and `Curtis' under zinc deficient conditions. Zinc had no significant effect on biomass and internodal length. Foliar nutrient contents were compared between cultivars. Our data suggest that genotypic differences in sensitivity to zinc deficiency exists and improving pecan production through genetic selection for zinc efficiency appears promising.
513 Simulated Shipment of Fresh-market Tomatoes Utilizing Controlled Atmosphere
Authors: Rushing James W.
Published: February 2019

Mature-green fresh-market tomatoes (Lycopersicon esculentum Mill.) were held at 11 °C under controlled atmosphere (CA) at 4% O2 and 4% CO2 in a commercial intermodal shipping container equipped with a membrane-based nitrogen-generating CA system. After 4 weeks, tomatoes in CA had 11.9% decay compared to 46.4% decay in control samples held at the same temperature under normal atmosphere. During storage, color development in controls progressed from green to the light red stage in more than 50% of the fruit and only 4.5% remained green after 4 weeks. In contrast, CA stored samples had 25.7% of the fruit in green condition and only 3.9% had progressed to the light red stage. Following CA exposure tomatoes were held at 20 °C with or without 250 ppm C2H4 treatment to observe ripening. All samples ripened normally without symptoms of chilling injury. Results suggest that CA is a useful method for reducing decay and delaying ripening during international transport.
515 Chlorophyll Fluorescence as an Indicator of Anaerobic Metabolite Levels for Broccoli in MAP and Subsequent Air Storage
Authors: DeEll J.R. , Toivonen P.M.A.
Published: February 2019

When the gas concentrations of modified atmosphere packaging (MAP) become extreme for broccoli (<2 kPa O2 and >10 kPa CO2), off-odors and off-flavors may develop via anaerobic respiration, rendering it unmarketable. We recently showed that chlorophyll fluorescence decreases when broccoli switches to anaerobic behavior in MAP. The objectives of this study were to determine: 1) if chlorophyll fluorescence returns to normal levels after the package is opened and hence the broccoli is exposed to ambient air, and 2) if chlorophyll fluorescence is related to off-odors that develop. Broccoli heads were held in MAP (2 to 3 kPa O2 and >10 kPa CO2) at 0 to 1 °C for 4, 7, 14, 21, or 28 days, and then 5 days in ambient air at 0 to 1 °C. Chlorophyll fluorescence of the broccoli decreased dramatically in MAP, and remained low during the subsequent 5 days in ambient air. Similarly, off-odors became worse and acetaldehyde, ethanol, and ethyl acetate increased in the broccoli with time in MAP. However, these compounds slightly decreased during the subsequent 5 days of storage in ambient air. Chlorophyll fluorescence parameters correlated negatively with off-odor development and acetaldehyde, ethanol, and ethyl acetate levels in the tissue.
520 Northeast Greenhouse IPM Notes—Regional Cooperation and Digital Technology Enhances Information Delivery
Authors: Willmott J.D. , Freeman R.N.
Published: February 2019

Rutgers Cooperative Extension and Cornell Cooperative Extension initiated a regional newsletter the Northeast Greenhouse IPM Notes. The goal of the newsletter is to improve greenhouse pest management practices through promotion of timely integrated pest management information that applies to the unique problems faced in the Northeastern United States. Interstate cooperation maximizes the professional expertise and resources available through several Land Grant Institutions. Extension educators at Cornell, Rutgers, Penn State Univ., and the Universities of Maryland and Connecticut, actively contribute feature articles, pest updates and other timely information through e-mail: Internet communication facilitates communication. The newsletter is prepared monthly and sent to 282 greenhouse growers, extension professionals and allied industry representatives in New Jersey, New York, Pennsylvania, Connecticut, Massachusetts, and other states. The newsletter is also published on the World Wide Web with color images of crop problems. Publishing of color images is facilitated by digital technology. This edition can be downloaded in color from the Rutgers Cooperative Extension Floriculture site: http://aesop.rutgers.edu/~floriculture/grower/ipmf.htm
521 The Effects of Privatization of British and Scottish Public Extension Programs on Agricultural Information Delivery and Technology Transfer
Authors: Murray Mike
Published: February 2019

The British and Scotish public extension programs are currently “privatized,” after a decade-long process aimed at this objective. While the British system is owned by a private corporation, the Scotish one is still operated by a public entity. In both situations, information is not freely dispensed, but sold through a subscription process. For a fee, a basic level of service, including newsletters, production/marketing/farm management bulletins, and a limited amount of telephone time with disciplinary/commodity experts, is provided. For an additional fee, farm visits or problem diagnostic services can be secured. The government is one of the largest customers in both systems, funding major “public good” natural resource projects, rural reviatization projects, and agricultural sector job re-training programs. This has significantly impacted the way that information is obtained and delivered to primary producers. These issues, and their implications, will be discussed in this presentation.
523 A Survey of Distance Learning Needs and Preferences in the Landscape/Nursery Industry
Authors: Mudge Kenneth W. , Hennigan Kelly
Published: February 2019

The role of cooperative extension in providing information to amateur and professional horticulturists is being profoundly altered by the availability of vast amounts of horticultural resources on the World Wide Web and other electronic media. Advances in computer-related instructional technologies including the Internet, have coincided with, and to some extent triggered, a burgeoning demand for non-traditional continuing education in practically all fields of knowledge, including landscape horticulture. Although there are numerous Web sites offering a wide range of gardening and related information, there are relatively few opportunities for structured learning in the form of on-line distance learning courses or instructional modules. In Fall 1999, we conducted a survey of the membership of the New York State Nursery/Landscape Association to determine priority-training needs that might be met by computer-mediated distance learning. One-hundred-seven companies, representing horticulture-based businesses throughout New York State, completed the surveys. Results from the survey indicated that 83% of those responding were interested in taking one or more computer-based distance learning course(s), that 67% were willing to provide financial support for continuing education of their employees, and that 95% have access to a personal computer. We have also collected data indicating subject matter preferences, interest in full-course and short-course offerings, levels of computer and Internet experience, and more. It is apparent from the findings in this study that the cooperative extension has a great opportunity to use the World Wide Web as a component of its role as an information provider. This research will contribute to designing effective approaches for teaching hands-on horticultural skills at a distance, thereby expanding the cooperative extension's ability to reach its intended audiences.
528 Modeling of Fruit Set in Apple—Approaches, Model Structure, and Initial Results
Authors: Lakso Alan N. , White Michael D.
Published: February 2019

Several models of apple tree carbon balance have been developed, including a simplified model by our lab. Tree photosynthesis and total dry matter production is the best characterized except for root growth and root respiration. Once dry matter is produced and partitioned to the different organs (another key problem for modeling), the effects of carbon availability to the fruits on their growth and abscission needs to be modeled. Our approach is based on an observed relationship between increased abscission with decreased fruit growth rate of populations of fruit. From several empirical studies of fruit growth and abscission during chemical thinning or imposed stress early in the season, a relationship was found between % abscission and classes of fruit growth rates. It appears to be best if the fruit growth rate is expressed as a percent of the growth rate of the fastest growing group of fruits in each study. Thus in the model the fruit growth allowed by the available carbon each day is compared to a pre-determined maximum growth rate for the cultivar. The percent-of-maximum growth rate then determines how much abscission will occur. Then the growth rate of the remaining fruit is calculated. Additional parameters of the model allowed for a multiple-day buffer of carbon availability, an imposed fruit number reduction (i.e. equivalent to hand thinning), and temperature effects. Although there are more improvements planned, the initial tests have been promising with the simulations showing realistic patterns of fruit abscission and fruit growth.
550 Mapping of QTL for Partial Physiological Resistance and Field Reaction to White Mold, Plant Architecture, and Plant Height in Common Bean
Authors: Park Soon O. , Coyne Dermot P. , Steadman James R. , Skroch Paul W. , Jung Geunhwa
Published: February 2019

The objective was to detect molecular markers associated with QTL for partial physiological resistance (PPR) to two white mold (WM) isolates, partial field resistance (PFR), plant architecture (PA), and plant height (PH) in a genetic linkage map constructed using recombinant inbred lines (RILs) from the cross `PC-50' (resistant to WM) × XAN-159 (susceptible to WM). Significant correlations (+0.39 and +0.47) were noted between the WM reactions in the greenhouse and field. A significant but negative correlation (–0.33) was observed between the WM reaction and PH in the field. Six QTL affecting PPR to isolate 152 were found on LGs 4, 5, 7, and 8. Six QTL affecting PPR to isolate 279 were found on LGs 2, 3, 4, 7, and 8. Five QTL for PFR were observed on LGs 2, 5, 7, 8, and 11. Two QTL affecting PA were detected on LGs 7 and 8. Two QTL affecting PH were identified on LGs 7 and 8. On one end of LG 8 marker H19.1250 was significant for PPR to both isolates. On the other end of LG 8 the region closely linked to the C locus was significantly associated with PPR to both isolates, PFR, PA and PH. Marker J09.950 on LG 7 was significantly associated with PPR to both isolates, PFR, PH and seed weight. Marker J01.2000 on LG 2 was the most significant locus for both PPR to the isolate 279 and PFR. QTL on LG 5 were found for PPR to the isolate 152 and PFR. Overall, four of the five QTL affecting PFR were also found for PPR to one or both isolates.
557 Germplasm Evaluation of Thirty-nine and Ecological Adaptation Trials of Seven Tomato (Lycopersicon esculentum) Varieties in Nigeria
Authors: Olufolaji O.A. Denton , Makinde Margaret J. , Akinfasoye J.A.
Published: February 2019

Nigeria has diverse ecological conditions, ranging from mangrove swamp of the southern coastal regions to the derived Savannah of the middle belt and the Sudan/Guinea Savannah of the Northern part of the country. Using the southern wet humid rainforest condition of NIHORT, Ibadan, two germplasm evaluation trials were carried out during the rainy season of May to Sept. 1996 and 1997. Thirty-nine tomato accessions were investigated on 1 × 4-m plots at 50 x75-cm spacing in a completely randomized block design with three replications. The top 10 and the least 10 accessions were evaluated for yield in terms of number and weight of both wholesome and unwholesome fruits. In the Northern Guinea Savannah, NHLY-10; Ti 423, and Ti 420 were the best three in terms of fruit number (141 to 117) and weight (673–583 g) per m2. In the northern Sudan Savannah, Ti. 420; NHLY, Äì7 topped the list with (125–72 fruits) and 500–420 g per m2. In the southern rainforest of Ibadan, NHLY, 10; Ti 420, and Ti 423 were superior in fruit number (33–12) and weight (327–150 g/m2 to all the other accessions. However, in the derived Savannah of Ikirun, Ti 423; Roma VF, AND Ti 420 with (85–56 fruits) and(589–278 g) per m2 were quite outstanding among the seven accessions.
558 Nutrient Allocation Patterns of Lupinus havardii Wats under Different Preharvest Ca Fertilization Regimes
Authors: Valenzuela-Vazquez Mario , Picchioni Geno A.
Published: February 2019

Lupinus havardii (Big Bend bluebonnet) is a winter annual plant indigenous to the semiarid southwestern U.S. with potential to become a new cut flower commodity. Nothing is presently known about the mineral nutrition of bluebonnet in greenhouse conditions, either in the whole plant or its short-lived cut racemes, and its possible relationship with vase life longevity. At first appearance of floral buds, supplemental Ca treatments (0, 2.5, 5.0, and 10.0 mm Ca using CaCl2) were added to the nutrient solution over a 2-month growing period, to evaluate the influence of Ca on plant nutrient allocation patterns, nutrient uptake and utilization, and raceme physiology after cutting. Ca supplementation increased net Ca uptake per plant by 40%, 77%, and 95% over the control (2.5, 5.0, and 10.0 mm Ca, respectively; P < 0.05). The increased Ca uptake per plant increased Ca concentration in racemes (a weak Ca sink), which resulted in marginal increases in vase life duration (1 day). This positive influence on vase life duration was not significant due to limited number of raceme replicates. When plants were supplemented with 5 mm Ca, the net accumulation of Ca, P, K, and Mg in roots increased by 4 to 5 times over the control roots. These increases occurred in parallel to an increase in root dry matter production. Similar patterns were observed in the net accumulation of Ca, P, K, and Mg per plant. In our conditions, Ca supplementation (5 mm) enriched raceme Ca concentration as well as whole-plant consumption of Ca, P, K, and Mg in bluebonnet plants. These data will be useful in developing fertilization strategies for this new and promising greenhouse floral crop.
563 Development of the Press Extraction Method for Plug Substrate Analysis: Quantitative Relationships Between Solution Extraction Techniques
Authors: Scoggins Holly L. , Bailey Douglas A. , Nelson Paul V.
Published: February 2019

Methods for extracting growing substrate root-zone solution include the saturated media extract (SME) and the 2 water: 1 substrate (v/v) suspension, neither of which are particularly suited to bedding plant plug systems. We have developed the press extraction method (PEM) as a simple and quick alternative to these methods. The grower simply collects a representative sample of plug trays and presses the top of the plug, collecting the expelled solution. Solution pH and EC can be measured immediately and the sample then sent to an analytical laboratory for nutrient analysis. Initial experiments demonstrated that differing manual pressures did not affect solution chemical properties. The PEM then was compared to the SME and 2:1 methods over a range of fertilizer levels and with peat- and coir-based substrates. Within substrates, pH, EC, and macronutrients were similar between the PEM and the SME. The level of dilution inherent in the 2:1 method resulted in much lower EC and nutrient levels when compared to the other two methods. Further experiments compared the PEM to the SME and 2:1 on plug flats collected from several commercial greenhouses and also those grown in the research greenhouse. The wide range of bedding plant species and fertility levels tested introduced variation needed to develop regression equations and correlations to create quantitative interpretation ranges for the PEM based on previously published sufficiency ranges for the SME and 2:1.
584 Cover Crop Evaluations for Eastern Washington Vineyards
Authors: Neumann Mercy A. , Wample Robert L. , Tarara Julie , Greene Stephanie
Published: February 2019

The location of the Columbia and Yakima valleys present vineyard managers in eastern Washington with significant concerns, particularly low rainfall and wind erosion. Cover crops, as part of a complete management system, can reduce the effects of wind erosion in vineyards by stabilizing soil particles and reducing runoff. Cover crops also reduce weed biomass. During research conducted at Prosser, Wash., 175 foreign and domestic species were assessed for performance as cover crops. Using a screening process, nine species were chosen for evaluation in large commercial plots. Grass species included cereal rye, crested wheatgrass, Sherman Big Blue wheatgrass, perennial rye, pubescent wheatgrass, and three fescues. Legume species included two annual clovers (Trifolium spp.) and two reseeding annual medics (Medicago spp.). Unseeded, resident vegetation served as a control. Vine and soil water statuses were monitored regularly. Initial establishment of all species was delayed because of low rainfall throughout the growing season; thus performance varied for each species. Drought-tolerant grass species had better germination and establishment than legumes, due to planting method. In-row water status and vine water potentials remained constant throughout the main portion of the growing season. A mix of crested wheatgrass, perennial rye, and pubescent wheatgrass (Canada mix) gave especially good cover without affecting vine or soil water status. Weed biomass was reduced in most cases, with legumes having least effect; cereal rye, crested wheatgrass and the Canada mix had the greatest effect. Season-long suppression was best achieved with the Canada mix because of the nature of establishment. In this study, most drought-tolerant grasses performed better than legumes; however, with proper establishment, legumes can be a beneficial part of a sustainable agriculture system.
590 Supplemental Application of Calcium and Nitrogen Improves Internal Quality of `Russet Burbank' Potatoes
Authors: Ozgen Senay , Gunter Christopher , Karlsson Bjorn , Palta Jiwan
Published: February 2019

Potato tuber tissue is calcium-deficient. Consequently, increasing Ca concentration is desirable to improve tuber quality. The purpose of the present study was to determine the influence of supplemental Ca and N fertilization on internal quality of potato. Three products (calcium nitrate, calcium chloride, and gypsum) were used to increase tuber calcium concentration. We tested combinations of both soluble sources of calcium and gypsum. Each treatment had five replications and received same total amount of N, supplied either from ammonium nitrate, liquid N (UAN: 50% urea + 50% ammonium nitrate) and calcium nitrate or combination of these sources (at rate of 225 kg·ha–1). The total Ca was applied at the rate of 168 kg·ha–1. Application of N at emergence and hilling (nonsplit) was compared to split application of N and Ca at hilling, 2, 4, and 6 weeks after hilling. At harvest, ≈100 tubers from each replication were cut in half along longitudinal axis and visually inspected for internal defect in both years. Application of Ca, especially in split schedule and from soluble sources, significantly increased tuber tissue Ca concentration. In 1998, the incidences of hollow heart (HH) and internal brown spots (IBS) were very low. The treatment containing calcium nitrate and calcium chloride combination produced the lowest total defects, whereas application of gypsum was not effective at reducing defects. In 1999, application of all Ca sources including gypsum, reduced HH and IBS. Data from these studies suggest that tuber calcium level is increased by field applications of moderate amount of Ca and tuber quality is impacted by N and Ca application. Furthermore, seasonal climatic variations appear to have dramatic influence on the incidence of internal defects in potato tubers.
591 MelonMan: A Simple Phenology Model of Muskmelon Development
Authors: Baker J.T. , Leskovar D.I. , Reddy V.R. , Dainello F.J.
Published: February 2019

A temperature experiment with two cultivars of muskmelon (`Gold Rush' and `Mission') was conducted in growth chambers to determine how main vine leaf appearance rates responded to temperature. We identified three cardinal temperatures for leaf appearance rate: the base temperature (10 °C) at which leaf appearance rate was zero, an optimum temperature where leaf appearance rate was at a maximum (34 °C) and an upper threshold temperature (45 °C) where leaf appearance rate returned to zero. Using these three cardinal temperatures, we constructed a simplified thermal unit accumulator for hourly measurements of air temperature. Main vine plastochron interval (PI), thermal time to harvest and final yield was determined for three cultivars of muskmelon (`Explorer', `Goldrush', and `Mission') grown in the field over six transplanting dates. The PI was calculated for each cultivar-transplanting date combination as the reciprocal of the slope of main vine node number vs. accumulated hourly thermal units (Tu). The PI was significantly affected by both cultivar and transplanting date. Final yield was sharply reduced in the last two planting dates, presumably due to high temperature stresses impacting reproductive development. As air temperatures warmed during the field experiment, the time interval from transplanting to 10% final harvest were reduced by between 21 to 28 days among the three cultivars and the first four transplanting dates. Our goal was to construct a simple muskmelon phenology model that could be run with easily obtainable weather station data and used by growers to quantify phenological development and aid in projecting harvest dates. We also wanted to test whether main vine node number was a useful description of vegetative development for muskmelon.
614 Ethephon Induced Differential Ripening and Enzyme Activity Response in Two Tabasco Lines
Authors: Motsenbocker Carl E. , Arancibia Ramon A.
Published: February 2019

Two tabasco pepper (Capsicum frutescens L.) lines were previously identified that differ in fruit detachment characteristics. Ethephon treatment (1000 μl/L) to intact tabasco fruit 29 days after anthesis (green-mature) enhanced ripening as indicated by fruit coloration in both lines. `McIlhenny Select' fruit, which normally separate readily at the red-mature stage, however, had a quicker ripening response compared to `Hard Pick' fruit. Ethephon increased cellulase activity in the fruit tissue of both tabasco lines compared to the untreated control, and there was a trend of higher cellulase activity in `McIlhenny Select' compared to `Hard Pick'. Differences in ripening and enzyme activity in response to ethylene generators indicate that the two tabasco lines are suitable material to investigate the physiological processes involved in pepper fruit ripening.
621 Optimizing Marigold (Tagetes erecta L.) Petal and Pigment Yield
Authors: Bosma Theresa , Dole John , Maness Niels
Published: February 2019

Marigold flower pigments can be extracted and used as a natural source of food colorants in the poultry and dairy industry. These pigments impart an orange color to egg yolks and a yellowish color to dairy products. We examined four African marigold cultivars for their ability to be commercially grown and harvested mechanically. `E-1236' yielded the highest quantity of lutein (22 kg/ha), a carotenoid pigment, using a spectrophotometer for quantification. `E-1236' and `A-975' were the earliest flowering cultivars, 11 June 1998 for transplants and 9 July 1998 for direct-seeded, at 8 weeks after sowing regardless of field establishment method. `E-1236' produced the greatest number of flowers in a production season, both as transplants (68 flowers/plant) and direct-seeded (57 flowers/plant) at 363,290 plants/ha. Transplants resulted in two more harvests in a single season than direct-seeded plants. Subsequently, more flowers and petal material were produced for pigment extraction than with direct-seeded plants. A one-time application of ammonium nitrate (28.02 kg/ha) at mid-season did not significantly effect flower number, flower weight, or pigment yield. Experiment was repeated in 1999 with four cultivars, two field establishment methods, seven harvest dates, and five nitrogen applications.
640 Developing Fertilizer and Substrate Practices for Organic Greenhouse Tomato Production
Authors: Miles Janet F. , Peet Mary M.
Published: February 2019

`Grace' tomatoes were grown utilizing three different growing methods: organic, conventional, and biorational (IPM and use of reduced-risk pesticides). There was one treatment per greenhouse per growing season. Treatments were rotated for each crop. Inputs for the organic system were allowable according to the Carolina Farm Stewardship Materials List for organic certification or the Organic Material Review Institute (OMRI). Organic methods were compared to conventional and biorational methods in a total of two spring and two fall crops. The conventional and biorational substrates consisted of a commercial peat/perlite blend containing a “starter” nutrient charge. The organic substrates were a coir pinebark blend and a peat/perlite/vermiculite commercial substrate without non-organic “starter nutrients” and wetting agents. Organic substrates were amended with 15% by volume vermi-compost and dolomitic lime. Organic nutrient amendments were bloodmeal, bonemeal, and potassium sulfate to provide an initial nutrient charge. Organic post-transplant fertilization practices included three commercial blends used at several application rates. Fertilizers were applied by “mixing and pouring” in Spring 1998, but were injected into the drip irrigation system for the remaining three growing seasons. Data was collected on harvest yield, fruit quality, and plant development. In the first two growing seasons, organic production resulted in the highest percentage of number1 quality fruit, but in Spring 1998, these plants were developmentally slow, resulting in lowest total yields. In the Fall 1998 and Spring 1999 crop, all measurements of growth and yield for organic production were comparable to those in conventional and biorational controls. We feel however, that additional development work is required in the organic treatments to optimize transplant production, post-plant fertilization regimes and biocontrol application.
650 Effects of Drought and Mechanical Brushing on Height of Tomato and Impatiens
Authors: Holt Kiffnie M. , Jennings Paul H.
Published: February 2019

Seeds of tomato `Big Beef Hybrid' and impatiens `Sun and Shade White' were sown in 200-cell plug trays and put under cyclic mist to germinate. After 3 weeks, the most uniform seedlings were transplanted to 24-cell flat inserts where they remained for the duration of the experiment. At 5 weeks, plants were arranged for the study with three flats per treatment. The mechanical group was brushed 50 times at 7:00 a.m., 1:00 p.m., and 7:00 p.m. The brushing mechanism was adjusted as needed to account for growth and stimulate only the top 1 to 2 inches of the plants. Water was withheld from the drought plants until water stress symptoms developed. Treatments continued for three weeks. At the termination of treatment, data was only recorded on the eight plants in the middle of each flat to reduce edge effects. Data collected included height, total stem length, total leaf area, and fresh and dry weight of both roots and shoots. Two more replications of the experiment were performed over the next 3 months. As expected, the treated plants were shorter than the controls and had a more compact and sturdy growth habit in all replications. Effects on leaf area, fresh weight, and dry weight were noted and will be discussed.
654 The Role of Plant Genetic Resources in Safeguarding Global Carrying Capacity
Authors: Bretting Peter
Published: February 2019

Plants provide humans with food, fiber, feed, ornamentals, industrial products, medicine, shelter, and fuel. As vegetation, they maintain global environmental integrity and the carrying capacity for all life. From an anthropocentric perspective, plants serve as genetic resources (PGR) for sustaining the growing human population. Research on PGR can provide basic knowledge for crop improvement or environmental management that enables renewable, sustainable production of the preceding necessities. PGR also provide the raw material for increasing yield and end product's quality, while requiring fewer inputs (water, nutrients, agrichemicals, etc.). The staples of life—30 or so major grain, oilseed, fiber, and timber species—comprise the “thin green line” vital to human survival, either directly, or through trade and income generation. Many crop genebanks worldwide focus on conserving germplasm of these staples as a shield against genetic vulnerability that may endanger economies and humanity on an international scale. Fewer genebanks and crop improvement programs conserve and develop “minor crops,” so called because of their lesser economic value or restricted cultivation globally. Yet, these minor crops, many categorized as horticultural, may be key to human carrying capacity—especially in geographically or economically marginal zones. The USDA/ARS National Plant Germplasm System (NPGS) contains a great number and diversity of minor crop germplasm. The NPGS, other genebanks, and minor crop breeding programs scattered throughout the world, help safeguard human global carrying capacity by providing the raw genetic material and genetic improvement infrastructure requisite for producing superior minor crops. The latter may represent the best hope for developing new varieties and crops, new crop rotations, and new renewable products that in the future may enhance producer profitability or even ensure producer and consumer survival.