bluuebunny/crossref_metadata_2025 huggingface dataset:
334 Seasonal Characterization of the Phenolic Layer Beneath Floral Buds of Rhododendron spp.
Authors: Salemi Michelle R. , Scott James D. , Chalker-Scott Linda
Published: February 2019

It has been previously shown that dormant, cold-hardy floral buds of Azalea possess layers of highly lignified and suberized cells below the bud axis and beneath each bud scale. Two species of deciduous Azalea were analyzed bi-weekly using differental thermal analysis (DTA) throughout their dormant season to determine the development of cold hardiness as denoted by low temperature exotherms (LTEs). Other buds collected at the same time were observed using fluorescence microscopy to document the relationship between the development of the barrier and the onset of cold hardiness. Preliminary analysis showed when buds were maximally cold hardy the barrier was most intact, and as buds began to lose hardiness, the layer started to degrade. These results suggest that in fact this layer of cells does act as the long-proposed bud barrier. In a comparison between the species, the hardier species (R. japonicum) was found to have a denser layer of phenolic-rich cells compared to buds of the less hardy species (R. occidentale). This finding further supports the relationship between the layer of cells and the existence of cold hardiness in bud tissues.
336 Seasonal Effects on Growth of Olneya tesota following Root Pruning
Authors: Martin Chris A. , McDowell L. Brooke
Published: February 2019

Seedlings of Olneya tesota A. Gray (desert ironwood) were grown in 12-L containers filled with a peatmoss and pumice substrate (1:1 v/v) for 3 months under simulated summer or winter Sonoran Desert conditions in a walk-in growth chamber. Growth room irradiance (550 mmol•m-2•s-1) was provided with an even mixture of mercury vapor and high-pressure sodium high-intensity discharge lamps. Growth room air temperature and relative humidity were ramped hourly to approximate typical summer or winter weather conditions based on mean seasonal climatological data for Phoenix, Ariz. For simulated summer conditions, maximum/minimum air temperature range was 40/28 °C and maximum/minimum relative humidity range was 25%/12%. Photoperiod was 16 h. For simulated winter conditions, maximum/minimum air temperature and relative humidity were 20/5 °C and 80%/35%, respectively. Photoperiod was 10 h. After 2 months, desert ironwood root systems were cleaned of substrate by floatation in a water bath, pruned to a length of 15 cm, repotted, and then grown for an additional month under the same conditions. Only 41% of desert ironwood survived root pruning under summer conditions compared with a 100% survival rate under winter conditions. For surviving desert ironwood, shoot and root extension growth was significantly greater under summer conditions.
343 Emergence of Five Lettuce Cultivars using Seeds Developed in Different Seasons
Authors: Greenwood Lynze , Coons Janice M. , Owen Henry R. , Ferguson Lisa , Wang Ronglin
Published: February 2019

Lettuce (Lactuca sativa) is one of the most important U.S. fresh-market vegetables with year-round consumption. For winter markets, lettuce is produced in the southwestern states with plantings in early fall when soil temperatures are high. Seed germination of lettuce, however, is inhibited by soil temperatures over 25 °C. The objective of this study was to test the emergence and growth of five lettuce cultivars using two seedlots produced in winter or summer to provide information for improving stand establishment at high temperatures. Seeds of five cultivars (`Empire', `Parris Island Cos', `Waldmann's Green', `Prizehead', and `Dark Green Boston') produced in Yuma, Ariz., during summer or winter months were used. Seeds were planted in a greenhouse mix in plastic trays and grown in a growth chamber at 23, 25, 30 and 35 °C. After 4 weeks, number of emerged plants, number of leaves, height, fresh weight, dry weight, and leaf area were measured. At lower temperatures (23 and 25 °C), more plants emerged and plants developed more rapidly than at higher temperatures (30 and 35 °C). More plants emerged of `Empire' and `Parris Island Cos' than of `Waldmann's Green' or `Dark Green Boston'. Growth varied greatly for the different cultivars. At 35 °C, only `Empire' winter seed emerged. At other temperatures, summer seed lots generally were better than or equal to winter seedlots. This information suggests that seeds developed during the summer are more vigorous at emergence than those developed during the winter.
344 Dormancy Breaking and Germination of Liriope spicata Lour.
Authors: Kim Ki Sun , Lee Ji Ny
Published: February 2019

There are many ground covers native to Korea. Liriope spicata is very promising for landscaping purposes due to its waxy and dark-green foliage fragrant and pink flowers, as well as fruit. However, seeds harvested during late fall do not germinate at all if they are sown in spring. Thus, series of experiments were conducted to undestand the physiological mechanism of dormancy breaking and germination of Liriope spicata Lour. seeds and to determine the effective methods for enhancing seed germination. Fruit were harvested in October through December. Depulped seeds germinated rapidly, indicating that one or more inhibitors may be present in the pulps of fruit and/or seeds. GA3, NaOCl, NaOH, and H2SO4 treatments and dry cold treatment had no effect on germination, whereas wet, cold seed treatment for at least 30 days promoted germination up to 75% within 15 days. Optimum conditions for germination was continuous dark and 25/20 °C alternate temperature conditions. Extracts from pulps and seeds showed a strong inhibition effects on the germination of lettuce seeds, indicating that germination inhibitors are present in pulp and seeds. Since extracts from naked seeds did not show inhibition, inhibitory substances are thought to be present in pulp and seedcoat. Pulp and seeds were extracted with water and methanol and autoclaved at 115 °C, followed by bioassay experiments. Germination inhibitors were found water soluble and heat stable by series of bioassay experiments. Diluted extracts 4 to 8 times still maintained inhibitory effects. Optimum seed harvesting time was from 22 Nov. to 1 Dec., where seed germination was high without additional seed treatments. Total phenolic compounds and ABA contents of pulp and seeds decreased by wet cold seed treatment. Changes in total phenolic compounds and ABA in from October through December were correlated with germination during the seed development. When contents of total phenolic compounds and ABA were high, seeds did not germinate at all, while low contents resulted in good seed germination.
347 1-MCP and CO2 Reduction of Ethylene Response on Snapdragon
Authors: St.Hill R. , Murr D.P.
Published: February 2019

Recent advances in technology have made the snapdragon, Antirrhinum majus L., a promising florist crop in North America and potentially on the Ontario market. CO2 is a known inhibitor of ethylene action, but its effects tend to be difficult to interpret based on the variable responses of plants to this gas. Recently, a gaseous ethylene analog has been shown to inhibit certain ethylene responses of cut flowers, such as wilting in carnations and flower abscission of cut phlox. This cyclic olefin, 1-methylcyclopropene (1-MCP), is thought to bind irreversibly to the ethylene receptor sites, thereby preventing or delaying ethylene responses. In the experiments undertaken, the potential of CO2 and 1-MCP were investigated for their ability to enhance vase life and to reduce shattering and wilting of snapdragons. Flowers were sealed in ≈0.2-m3 chambers encased in 6-mil polyethylene and exposed to elevated CO2 (5% or 10%) or 1-MCP (20-200 nL/L) for 6 to 24 h at 20 °C. The flowers were then exposed to continuous ethylene of 0-20 μL/L. Following exposure to 5 or 20 μL/L ethylene, 1-MCP reduced shattering ≈2- to 3-fold compared to CO2 treatment. 1-MCP did not prevent the wilting response but delayed it by ≈2 days. CO2-treated flowers exhibited a more rapid decline in net percent open florets from days 3 to 5 post-treatment. Despite the ability of 1-MCP to reduce shattering, in the absence of exposure to continuous ethylene, it has limited effectiveness on wilting compared to CO2.
353 Flavor, Sensory, and Postharvest Evaluations of Commercial- vs. Tree-ripe Fresh-cut `Bounty' Peaches
Authors: Beaulieu John C. , Bett Karen L. , Champagne Elaine T. , Ingram Daphne A. , Miller James A. , Scorza Ralph
Published: February 2019

Many consumers do not buy peaches due to the fuzzy skin and seed stone and because out-of-season peaches do not possess optimum tree-ripe flavor. The feasibility of using a non-browning freestone peach to deliver high-quality fresh-cut products was investigated. Changes in fresh-cut flavor, texture, and postharvest attributes of commercial-ripe (CR) vs. tree-ripe (TR) harvested and shipped `Bounty' peach was assessed. Fresh-cut CR wedges had an initial firmness of 20.9 N, whereas TR wedges had 11.2 N. On day 2, firmness decreased roughly 3% to 12% and 35% to 45% for CR and TR wedges held at 1 °C, respectively. By day 5, CR wedges hardened (24.5 N) whereas TR did not return to their initial firmness; increasing marginally through day 7. Sensory panel hardness for CR did not change through storage, but with TR wedges, hardness decreased through day 2 then increased until day 7. Little variation was noted in the initial soluble solids for CR vs. TR wedges (11.7, vs. 11.4 °Brix, respectively). After 7 days storage, °Brix decreased 7.5% to 12% in CR and 4.5% to 12% in TR wedges. Yellow flesh color (b*) decreased in all CR and TR treatments through storage. Flavor compounds in expressed juice were analyzed by solid phase microextraction with GC-MS. Several peaks were identified that may be associated with flavor-related changes that occurred during storage. For example, low molecular weight acetates and 6C compounds almost disappeared during storage, whereas short chain fatty acids, lactones, and palmitic acid increased markedly through storage. In TR, the “fruity” descriptor decreased throughout storage and “sweet aromatic” increased slightly (day 2) then decreased through day 7.
357 Combinations of GA3 and AVG Delay Fruit Maturity, Increase Fruit Size, and Improve Storage Life of `Feicheng' Peaches
Authors: Ju Zhiguo , Duan Yousheng , Ju Zhiqiang
Published: February 2019

`Feicheng' peach is a favorite cultivar in China due to is large size and high eating quality. However, its storage quality is poor and its market life is relatively short. Different combinations of AVG and GA3 applied at various stages of fruit development were evaluated to prolong market life of this fruit. A combination of 80-100 mg/L AVG and 80-100 mg/L GA3 at the end of pit hardening gave the best results. This treatment retarded the change in ground color, loss of firmness, and reduction in acidity by2 to 3 weeks. Since harvest was delayed, soluble solid content increased compared with the control that was harvested earlier. Fruit size increased significantly on treated trees. During 6 weeks of storage at 0 °C, ethylene evolution increased and fruit firmness decreased slowly in control fruit, but in AVG+GA3-treated fruit, they did not change from the low initial levels. At the end of storage, control fruit developed a high percentage (83%) of tissue browning and mealiness after warming at 20 °C for 4 days, but the AVG+GA3-treated fruit ripened normally and developed much less (16%) tissue browning and mealiness. Our results showed that the market life of `Feicheng' peaches can be prolonged by at least 4 weeks by using the AVG+GA3 treatment to delay harvest and improve storage quality.
373 Phenolics and Lipid-soluble Antioxidants in Fruit Cuticle of Apples and Their Antioxidant Activities in Model Systems
Authors: Ju Zhiguo , Bramlage William J.
Published: February 2019

Phenolics were extracted from fruit cuticles of `Delicious', `Golden Delicious', `Empire', and `Cortland' apples, using either cuticular wax scraped from fruit peel or enzyme-isolated cuticles. The concentrations of free phenolics in fruit cuticle ranged from 8 to 45 mg•g-1, and bound phenolics ranged from 50 to 110 mg•g-1 in these cultivars. Free cuticular phenolic concentrations in the four cultivars were in the order `Golden Delicious' > `Delicious' > `Empire' > `Cortland'. In a linoleate emulsion (oil-in-water) system, diphenylamine (DPA, lipophilic) displayed higher antioxidant activity than methanol-extracted cuticular phenolics (hydrophilic). In an α-farnesene-hexane (bulk oil) system, however, antioxidant activities of methanol-extracted cuticular phenolics were higher than that of DPA. Lipid-soluble antioxidants (LSAs) from cuticle displayed higher activity in the linoleate emulsion system than in α-farnesene-hexane system. Only about 10% to 15% of the total LSA activity in fruit peel was detected in isolated fruit cuticle. Among the four cultivars, LSA activity in epidermal and hypodermal cells was similar in `Golden Delicious', `Empire', and `Cortland' apples, while `Delicious' had lower activity.
375 Mono-, Di-, and Tri-acylglycerols and Phospholipids Inhibit Scald Development in `Delicious' Apples
Authors: Ju Zhiguo , Duan Yousheng , Ju Zhiqiang
Published: February 2019

Effects of different plant oils (soybean oil, corn oil, olive oil, peanut oil, linseed oil, and cotton seed oil) and oil component emulsions on scald development in `Delicious' apples were studied. Prestorage treatment with commercial plant oils reduced scald development, but was not as effective as 2000 mg•L-1 diphenylamine (DPA) after 6 months of cold storage. Different oil components played different roles in affecting scald. At 6% or 9% concentrations, neutral lipids (mono-, di-, and tri-acylglycerols), and phospholipids inhibited scald to the same level of 2000 mg•L-1 DPA treatment. Free fatty acids partially reduced scald, while α-tocopherol at 3% or higher concentrations accelerated scald development. There were no differences in scald inhibition between unsaturated neutral lipids and saturated neutral lipids or among the different acylated neutral lipids. When α-tocopherol was stripped from plant oils, the stripped plant oils at 6% or 9% controlled scald to the same level of 2000 mg•L-1 DPA treatment. Emulsions of 6% or 9% neutral lipids, phospholipids, or stripped plant oils did not induce greasiness on fruit skin. Fruit treated with lipids, phospholipids, or stripped plant oils looked greener and fresher compared with the control by the end of storage.
377 Differential Human Antiplatelet Activity of Selected Allium Thiosulfinates
Authors: Briggs W.H. , Xiao H. , Parkin K.L. , Goldman I.L.
Published: February 2019

The acute syndromes associated with many human diseases of the cardiovascular system such as myocardial infarction, angina, and some forms of stroke are caused by thrombosis. Platelet aggregation plays a central role in thrombus formation. Dietary intake of inhibitors of aggregation may provide protection against these disorders, which effect millions of Americans. Previous research in our laboratory has shown that juice from onion (Allium cepa) inhibits platelet aggregation ex vivo. Various sulfur-containing compounds are largely responsible for the distinctive aromas, flavors, and platelet inhibitory actions of onion. Among these is the thiosulfinate (TS) family of compounds formed upon maceration of the vegetable. In this study, several pure Allium compounds were evaluated for antiplatelet activity. TSs were synthesized in model reaction mixtures containing the enzyme allinase and S-alk(en)yl-L-cysteine sulfoxides (ACSOs), their natural precursors, or purified from garlic juice. Antiplatelet activity of each compound was determined by dose response using whole blood from human donors. A minimum of 0.4 mM methyl methaneTS, a compound found in freshly cut onion and garlic (Allium sativum), was needed to significantly inhibit aggregation relative to a non-TS control. By contrast, a lower concentration (0.05 mM) of 2-propenyl 2-propeneTS (allicin) and propyl propraneTS, compounds found in garlic but not onion, was required. The garlic compound methyl 2-propeneTS significantly inhibited at 0.2 mM. These data imply a role of alk(en)yl groups in TS antiplatelet efficacy. Variability in ACSO-derived TS composition in cut onion tissue may explain differential antiplatelet activity of onion cultivars. Results from this investigation suggest that ACSO and TS composition profiles may be useful for evaluating the medicinal value of Alliums.
385 Honey Dew Fruit Senescence is Regulated by Polyamine Inhibition of Lipid Peroxidation
Authors: Lester Gene
Published: February 2019

Polyamines are effective scavengers of activated oxygen free radicals produced by lipoxygenase (LOX) and phospholipase-D (PL-D). Activated oxygen free radicals cause peroxidative damage to membranes and hasten senescence. Exogenous polyamine spermidine (SPD) compared to spermine (SPM) at 1 mM or no polyamine was an effective inhibitor of honey dew (Cucumis melo L. var. inodorus) membrane peroxidation, as determined by malondialdehyde (MDA), following dark incubation for 6 or 48 hours of fully abscised fruit hypodermal mesocarp tissue. MDA levels in SPD-treated tissue was lowest in both 6 and 48 hours compared to SPM or no polyamine. SPD was effective in slowing lipid peroxidation as MDA was highly negatively correlated with the loss in total chlorophyll, plasma membrane H+ pumping ATPase activity, and microsomal phospholipid content (r = -0.89, -0.64 and -0.57, respectively). Both LOX and PL-D enzyme activities were not correlated with the total chlorophyll and microsomal membrane phospholipid losses or MDA levels, demonstrating that these enzymes act indirectly in the degradation of membranes through the production of lipid peroxidating free radicals. The results also demonstrate that the effect of polyamines as anti-senescence compounds is through direct inhibition of lipid peroxidation and not by affecting LOX or PL-D free radicle production.
389 Volatile Profile of `Marion' Blackberry
Authors: Perkins-Veazie P. , Finn C. , Baldwin E.
Published: February 2019

Oregon produces most of the processing blackberries in the United States. `Marion' blackberry (Rubus hybrid) is a trailing, thorny plant type with fruit highly prized for its unique flavor and superior processing quality. Blackberries developed in other parts of the United States grow well in Oregon but differ in flavor from `Marion' fruit. `Marion' blackberry plants are thorny and highly susceptible to freeze injury; growers desire a thornless, higher yielding, and more winter tolerant plant with similar fruit flavor and quality. This experiment was done to identify volatiles unique to `Marion' that may be incorporated into new germplasm. Forty-two volatile peaks were identified in blackberries using headspace gas chromatography and known standards. Ethylacetate and trans-2-hexenol were present in very low amounts and nerilidol was present in an unusually high amount in fresh `Marion' homogenates relative to other blackberry cultivars. Nerilidol is a volatile commonly associated with raspberry flavor and may come from the raspberry germplasm in the breeding background of `Marion'. It appears that the flavor of `Marion' fruit results from proportional differences in several volatile compounds rather than the presence of volatiles unique to this cultivar.
391 Compression Bruising Alters the Strawberry Volatile Profile
Authors: Archbold Douglas D. , Clements Ann M. , Hamilton-Kemp T.R. , Collins R.W.
Published: February 2019

Prior work indicated that volatile compounds produced by macerated strawberry fruit occurred at levels capable of affecting pathogen development. To determine if a less-severe injury, such as bruising, would alter the volatile profile of strawberry fruit, the headspace volatiles from ripe `Tribute' strawberry fruit were sampled with SPME fiber during the 15 min immediately following and from 75 to 90 min following application of a compression bruise. The compression bruise was applied with a force gauge, and fruit were kept in a closed bottle at room temperature during the study. Of the 14 major volatile products consistently produced by all fruit, acetate esters derived from hexanal, (E)-2-hexenal, and (Z)-3-hexenal increased most, over 50%, in response to bruising during the first interval. During the later interval, bruised fruit produced over 50% more (E)-2-hexenyl acetate and hexyl acetate than control fruit. Most notably, the ratio of levels of (E)-2-hexenyl acetate produced by bruised compared to control fruit were the highest among all 14 major volatiles, over 150% more after 15 min and 270% more at 90 min. Headspace levels of the 6-carbon acetate esters declined for both control and bruised fruit between 15 and 90 min, while levels of the other major volatiles increased. The other 11 volatile compounds were commonly identified aroma volatiles. Headspace levels of some of these were also higher from bruised than control fruit. In particular, headspace levels of ethyl butyrate were increased by bruising 13% after 15 min but over 100% after 90 min, the most of any volatile product other than (E)-2-hexenyl acetate.
401 Assessing Crop Canopy Development Using a Digital, Red/Near-infrared Band Ratioing Camera
Authors: Peters D.W. , Mitchell J.P. , Plant R.E. , Hanson B.R.
Published: February 2019

Current methods of making crop cover estimates are time-consuming and tend to be highly variable. A low-cost, digital, red/near-infrared band ratioing camera (Dycam Inc., Chatsworth, Calif.) and accompanying software (S. Heinold, Woodland Hills, Calif.) were evaluated for estimating crop cover. The camera was tested using a set of images having leaf areas of known sizes with different crop, soil, and lighting conditions. In the field, camera-based crop cover estimates were compared to light bar measured estimates. Results indicate that the camera and image analysis software are capable of estimating percent crop cover over a range of soil, crop, and lighting environments. Camera-based crop cover estimates were highly correlated with light bar estimates (tomato r2 = 0.96, cotton r2 = 0.98). Under the conditions tested, the camera appears to be a useful tool for monitoring crop growth in the field.
404 Cyclic Cold Temperature Stresses Before Transplanting Influence Cantaloupe Seedling Growth and Earliness But Not Total Yield or Quality
Authors: Korkmaz Ahmet , Dufault Robert J.
Published: February 2019

Cantaloupe seedlings may be repeatedly exposed in the field soon after transplanting to temperatures alternating between almost freezing and optimal temperatures. In the first year of a 2-year study, `Athena' cantaloupe seedlings were exposed in walk-in coolers to temperatures cycling from 2 °C for 3, 6, and 9 hours daily to 25 °C for the rest of the 24-h period. Cold stress was repeated for 1, 3, 6, and 9 days before field planting. In the second year, transplants were exposed to 2 °C for 3, 6, and 9 hours for 3, 6, and 9 days before field transplanting. The objective of this study was to determine the long-term effect of early season cold temperature exposure on seedling growth, earliness, yield and quality by simulating the cold/warm alternations possible in the field in coolers. Cold-stressed transplants were planted in the field after all risk of ambient cold stress was negligible. In both years, exposure to cycling cold temperatures generally did not effect total productivity and fruit quality, although seedling growth characteristics were reduced in response to longer cold-stress treatments. In the second year, early yield was reduced by exposure to increasing hours of cold stress, but this was not significant in the first year. Therefore, cold temperature stresses occurring in the field at transplanting have negligible effect on yield potential of `Athena' cantaloupe.
414 The Effect of Water Availability on Rose Photosynthesis and Calorespirometric Properties
Authors: Raviv M. , Lieth J.H. , Burger D.W.
Published: February 2019

Rose plants (cv. Kardinal, grafted on Natal Brier) were grown in UC mix (42% fir bark, 33% peat, and 25% sand) and in coir. Water tension in the media was maintained within a predetermined narrow range using electronic tensiometers. Whole plant net photosynthesis as a function of the water tension in the medium was determined and the results were later normalized to measured leaf area. Simultaneous measurements of metabolic heat and respiration rate were carried out on detached young (FW = 10-20 mg.) leaflet samples, using differential scanning calorimeter (model 4100, Calorimetry Sciences, Provo, Utah). Only a small amount of plant material is removed for analyses so the assay is essentially non-destructive for the whole plant. Physical characteristics of the media greatly affect the relationship between water tension and water availability to plants. At similar tension values, water availability is much lower in coir than in UC mix. The effects of water availability on net photosynthesis, metabolic heat rate, and respiration will be discussed in relation to their effect on productivity.
417 Earthworm Castings as a Media Amendment for Poinsettia Production
Authors: Hidalgo Pablo R. , Harkess Richard L.
Published: February 2019

An experiment was conducted to determine the effect of earthworm (Eisenia fetida andrei) castings derived from sheep, cow, or horse manures on the growth of poinsettia (Euphorbia pulcherrima `Freedom Red'). Poinsettia cuttings were transplanted to 1-L (15-cm-diameter) plastic pots that were filled with castings:peat moss at 1:0, 1:3, 1:1, 3:1, or 0:1 by volume for each animal manure evaluated. Plants were fertilized using 200 ppm N from a 15-5-25 (N-P2O5-K2O) fertilizer applied with the irrigation water. Total bract area and growth index were greatest in those treatments consisting of 3:1 and 1:1 (castings:peat) from sheep and cow manures, 1:0 (castings:peat) from cow manure and for growth index only, 1:0 (castings:peat) from horse manure. For these two characteristics, 100% sheep manure castings and 100% peatmoss had the lowest values. The time to anthesis was least when poinsettias were grown in 3:1 or 1:1 castings:peat from sheep and cow manures and 1:3, 1:0, or 3:1 from sheep, cow, or horse manure respectively. Anthesis was most delayed when plants were grown in 100% castings from sheep manure.
428 In Search of the Kentucky Tomato
Authors: Rowell Brent , Jones Terry , Snyder John , Nesmith William
Published: February 2019

We began trials of vine-ripened, staked tomato cultivars in 1998 to identify a variety suitable for marketing as a premium “Kentucky Tomato”. In conversations with marketing specialists at the Kentucky Dept. of Agriculture and merchandising managers at the Kroger Company's regional distribution center, we identified essential qualities of our ideal Kentucky tomato. A carefully selected group of 16 varieties was evaluated at two locations for yields, appearance, quality, disease tolerance, and taste. New varieties were compared with commercial standards like `Mountain Spring'. Yields of different sizes and grades of marketable fruit were multiplied by appropriate real-market prices for a given harvest date and summarized in a single income-per-acre variable for each variety. Some of the highest yielding varieties in eastern Kentucky (`Fabulous' `Sunbeam') appeared to have some tolerance to early blight; other varieties in this highest-yielding group included `Emperador', `Enterprise', `Sunleaper', and `Sunbrite'. All of these had fruit quality we considered acceptable for commercial markets with the exception of `Sunbrite'. `Fabulous', `Emperador', `Sunleaper', `SunGem', and `Sunpride' were the highest yielding varieties in central Kentucky. `Sunleaper' and `Sunpride' appeared somewhat tolerant to tomato mosaic virus (ToMV), which occurred at this location. Preliminary taste tests identified six varieties that were evaluated further by consumers at a local farmers' market. `Mountain Fresh' and `Floralina' were considered the best tasting varieties overall. The search continues in 1999.
431 Fruit Sugar and Yield of Three Muskmelon as Influenced by Spacing and Genotype
Authors: Kultur F. , Harrison H.C. , Staub J.E.
Published: February 2019

Muskmelon (Cucumis melo L.) genotypes, Birdsnest 1 [`Qalya' (BN1)], Birdsnest 2 (BN2), and `Mission' (V) were used to determine the effects of plant architecture and spacing on fruit sugar concentration and yield. The BN1 and BN2 genotypes possessed a highly branched growth habit specific to birdsnest melon types but not characteristic of standard indeterminate vining types (e.g., `Mission'). Experiments were conducted at the Hancock (sandy soil, <1% organic matter) and Arlington (heavy, praire loam soil, >4% OM) Experimental Farms in Wisconsin. Plant response to two within-row spacings [35 cm (72,600 plants/ha) and 70 cm (36,300 plants/ha)] in rows on 210-cm row centers was examined. Genotypes were grown in a randomized complete-block design with four replications at each location and evaluated for primary lateral branch number, fruit number per plant, fruit number per hectare, average fruit weight, yield (g) per plant, yield (MT) per hectare, and fruit sugar concentration. All genotypes produced higher yield, fruit number and sugar concentration on the mineral soil at Arlington compared to the sands at Hancock. The main effect of genotypes was significant for all traits examined. BN1 and V genotypes had greater yield (gram per plant, yield per hectare, and average fruit weight) as well as higher fruit quality (fruit sugar concentration) than the BN2 genotype. Spacing affected all traits examined except primary branch number and fruit sugar concentration. As withinrow spacing increased from 35 to 70 cm, fruit number per plant, yield per plant and average fruit weight increased. However, yield (MT) per hectare and fruit number per hectare decreased. Fertility was adjusted according to soil tests for the two different soil types at the two farm locations.
432 Concept Mapping: Helping Students Make Connections in Landscape Design History
Authors: VanDerZanden Ann Marie
Published: February 2019

The Landscape Design Theory class at Oregon State Univ. is composed of undergraduate students from a variety of majors including, horticulture, housing and interior design, business, criminal justice, and art. This diversity of majors means there is a wide range of student knowledge about the history of landscape design and creates a unique teaching opportunity. To capitalize on this diversity and to encourage student participation, concept or knowledge maps were used at the beginning of the term before the material being covered in class lectures. Students were divided into groups of three and asked to develop a group concept map. They were given major societies or events that occurred in history from about 2000 BC (ancient Egypt) through the early 20th century. Additionally each group was given a list of 20 landscape design elements or features. Initially each group developed a historical timeline. After the timeline was complete they linked the different landscape design elements or features with a historical era thereby creating a map of their understanding of landscape design history. After the landscape design history segment of the class was completed the small groups reconvened and evaluated their initial concept map in light of the recently completed lectures. Each group discussed their original map, what associations were correct, and how they would do it differently with their newfound understanding of landscape design history. A class discussion followed regarding initial perceptions and benefits of this learning activity. This teaching strategy could easily be adapted to a number of other horticulture topics.
436 De Novo Synthesis of a Horticulture Teaching Program
Authors: Tignor Milton E. , Lamb Elizabeth M.
Published: February 2019

The Univ. of Florida has had off-campus degree programs for over a decade. In 1998, a new program in a major agricultural region of the state developed under unique circumstances. Community driven support, leadership from local politicians, and guidance from academic administrators resulted in the legislative funding of a new undergraduate teaching program in south Florida. The program offers upper-division courses leading to Bachelor of Science degrees in horticultural science and food and resource economics. Another unique aspect was the partnership formed with local universities necessary to offer the degrees. Locally, Indian River Community College provides lower-division courses and Florida Atlantic Univ. offers four upper-division courses to complete the course offerings for the degrees. Funding was allocated for eight new faculty members with 70% teaching appointments, four support staff, and a new $3.7 million teaching complex. In today's academic climate, having eight new faculty members at one time is a rare occurrence that allowed for creative growth on the part of the new teaching program. What was successful and unsuccessful concerning recruitment, advertising, purchasing, advising, collaborative efforts with local colleges, and administration will be discussed. In addition, demographics on the student body will be presented.
438 Optimization of a SPME Method for Flavor Characterization in Fresh-cut Cantaloupe
Authors: Beaulieu John C. , Rausch Allison K. , Champagne Elaine T.
Published: February 2019

Fresh-cut melons in many consumer-ready packages are notorious for “wetting” and accumulation of standing juices. These conditions likely create undesirable flavor and aroma changes. We initiated a study to investigate flavor changes in stored fresh-cut cantaloupe. One objective was to optimize solid phase microextraction (SPME) to evaluate organoleptic compounds. Static head-space SPME analyses were performed on fresh-cut cantaloupe cubes (≈2.5 mm, 5 mm, or 2.5 cm), expressed juice, and homogenized slurries. SPME fiber (100 μm PDMS vs. 75 μm Carboxen/PDMS) exposure time (5, 7.5, 10, 12.5, 15, 17.5, 20 min) was evaluated at 40 °C with various head-space: product ratios, plus or minus NaCl to produce typical chromatograms. Fibers were desorbed in an HP5890 GC with a DB-624 or DB-5 column for 45-min runs and an HP6890 GC (DB-5) equipped with a 5973 MS detector for 35-min runs. Albeit qualitative, the best chromatograms were obtained with 7-ml slurries, stirred with NaCl, exposed to a 10 0μm PDMS SPME fiber for 12.5 min. The 100 μm PDMS fiber produced better chromatograms considering the fact that many important flavor volatiles are low-molecular-weight polar esters and alcohols. These conditions were subsequently used to analyze numerous fresh-cut cantaloupe samples stored various times (0 to 9 days). Over 100 peaks were identified, many of which changed through storage and some are suspected as probable agents responsible for undesirable flavor changes. Our analyses are progressing in an attempt to authenticate compounds associated with flavor-related changes in numerous fresh-cut cantaloupe varieties from various growing regions.
443 Postharvest Physiology and Quality Maintenance of Fresh-cut Pears
Authors: Gorny James R. , Kader Adel A.
Published: February 2019

The optimal `Bartlett' pear ripeness stage for fresh-cut processing based on flesh firmness ranges between 44.5 and 58 N (10 and 13 lbf). Use of softer pears reduces postcutting life due to flesh browning. Firmer pears may have longer postcutting life but lack good flavor. Dipping pear slices in a mixture of 2% (w/v) ascorbic acid + 1% (w/v) calcium lactate + 0.5 (w/v) cysteine (pH 7) for 5 min at 20 °C extended their shelf-life by inhibiting flesh softening and surface browning during storage at 0 °C for 10 days. After 3 days at 0 °C, ascorbic acid and cysteine residues dropped below detectable levels, while calcium content was double that of untreated slices. Preliminary sensory evaluation indicate no negative impact on flavor from this dip treatment. Exposure of intact pears to heat (35 or 40 °C) or controlled atmospheres (0.25 kPa O2 and/or 40 kPa CO2) for 24 or 48 h did not influence postcutting cut surface browning of pear slices. Storage of `Bartlett' pears at -1 °C in 2 kPa O2 (balance N2) resulted in longer postcutting life of the slices as compared to those made from air-stored pears at -1 °C. The longer the storage duration of whole pears, the shorter the shelf-life of their slices was. Fruit size did not affect the postcutting life of the pear slices, provided that they were treated with the ascorbic acid + calcium lactate + cysteine mixture. Untreated slices made from small pears exhibited surface browning faster than those made from large pears.
445 Solid Matrices for Supporting Plant Growth in Space
Authors: Stutte Gary W. , Goins Greg
Published: February 2019

In preparation for a spaceflight experiment to measure photosynthesis of wheat (PESTO), four solid media were evaluated for use in the rooting modules of the Biomass Production System (BPS), a new plant growth unit for microgravity. The media were commercial peat-vermiculite (PV) mixture, zeolite developed at Johnson Space (Z/JSC), commercial zeolite developed by Boulder Innovative Technologies (Z/BIT), and arcillite (AR) with slow-release fertilizer. Wheat (cv. USU Super Dwarf) was grown in the media at 1500 μmol/mol CO2, 350 μmol·m-2·s-1 PAR, 23 °C, and 75% relative humidity for 18 to 21 days. Water was delivered to the media through porous tubes imbedded in the media, and NDS pressures of -0.1 to -0.5 kPa were maintained with either a static or recirculating standpipe. Plant height, leaf area, and fresh mass were determined for each experiment. Results indicated that the AR and Z/BIT media resulted in larger and more uniform plants than Z/JSC or PV at the same NDS pressure. Additional experiments were conducted with AR to evaluate interactions between particle size and NDS pressure. At ≈14 days after planting, there was a loss of NDS prime in AR >2.0 mm when the NDS pressure was less than -0.3kPa. This resulted in drying of the media and poor plant growth. There was excess water in the media, which resulted in reduced plant size, in AR <1.0 mm at NDS pressures more than -0.3 kPa.
448 Soil Problems Affecting Date Palm Growth, Yield, and Fruit Quality in Coachella Valley
Authors: Abdul-Baki Aref A. , Aslan S. , Cobb S. , Beardsley E. , Burke T.
Published: February 2019

A 3-year experiment was conducted to identify problems in Coachella Valley date palm (Phoenix dactylifera) orchards that limit vegetative growth, yield, and fruit quality. Major problems that were identified included soil compaction and stratification that restrict water permeation into the root zone, and low fertility as reflected by the low organic -matter content of the sandy soils. To eliminate the impact of these stresses on plant growth, yield, and fruit quality, a no-tillage alternative management system was introduced to replace the conventional practice of tillage that compacts the soil. No-till was coupled with the use of cover crops to enrich the soil with organic matter, fix N, recycle nutrients, and improve water holding capacity of the sandy soil. In already established orchards, an additional treatment—slip plowing—was also implemented to loosen the soil at lower depths to facilitate water permeation. The positive effects of the alternative system on the soil, tree growth, yield, and fruit quality will be presented.
452 Evaluation of Midrib Nitrate-N Tests for Desert Lettuce
Authors: Sanchez Charles A. , Peralta M.
Published: February 2019

Criteria for managing fertilizer nitrogen (N) applications for lettuce (Lactuca sativa L.) based on midrib nitrate-N analysis were developed 25 years ago. However, this test had not been recently evaluated for the newer cultivars of lettuce currently grown or the higher yield potential now obtained. More recently, quick sap nitrate-N tests have been correlated to the traditional dry midrib test and preliminary criteria for making diagnosis based on these sap tests have been proposed. Field experiments were conducted at 20 locations across the low desert region of the southwestern United States from 1996-1999 to evaluate the traditional dry midrib and sap nitrate-N tests. Tissue samples were collected before each sidedress N application and diagnostic accuracy was evaluated by determining lettuce growth and yield on both N-treated and untreated plots and comparing predicted to actual response. Overall, the variability associated with the quick sap test seemed to limit its application as a predictive N management tool in the low desert. Although less variable than the quick sap test, the high frequency with which the dry midrib test resulted in incorrect diagnosis suggests that either this test needs revision or that it is an unreliable N management tool.
457 Woody Plant Selections and Introductions from North Dakota State University
Authors: Herman Dale E. , Chaput Lawrence J.
Published: February 2019

Woody plant improvement research has been an active program at North Dakota State Univ. (NDSU) for many years. Eighteen cultivars have been introduced since 1986, and ≈10 additional releases are anticipated over the next 6 years. These superior, winterhardy cultivars have increased the inventory of adapted woody plants for landscape use in the northern plains, particularly USDA hardiness zones 3 and 4. Emphasis will be placed on recent introductions and promising plants for potential future release. An extensive, statewide cooperative evaluation program is conducted at seven sites throughout North Dakota and also at the NDSU Research Arboretum near Absaraka.
461 Genetics of the Necrotic Reaction to Lettuce Mosaic in Lettuce
Authors: Ryder Edward J
Published: February 2019

Lettuce mosaic has been a serious virus disease for lettuce in all locations worldwide where lettuce has been grown. Consequently, the disease and its virus have been well studied. Lettuce plants react to lettuce mosaic virus in a variety of ways. The most common susceptible reaction is an overall vein clearing and mottling, followed by leaf recurving, leaf distortion, and stunting. However, some susceptible types manifest a mild mottling with little additional distortion. Others develop a necrotic reaction, which may be severe, mild, or seasonal. Finally, there are at least three resistant reactions, most frequently appearing as a systemic infection manifested with restricted yellowish lesions. Research is ongoing to sort out the various reactions and their genetic bases. This report describes the inheritance of the severe necrotic reaction and its relationship to the resistant reaction conferred by the allele mo-1. Several previous crosses among necrotic types indicate that the same necrotic allele is operating except that found in `Bibb'. Several crosses were studied. The cross `Salinas' (mot.) × `Crisp As Ice' (nec.) showed that necrotic is due to a single dominant allele. The cross `Salinas 88' (res.) × `Maikonig' (nec.) produced three phenotypes in F2, indicating the action of two loci. The crosses PI 251245 (res.) × `Prizehead' (nec.) and `Vanguard 75' (res.) × `Prizehead' disclosed two recombinant phenotypes, mottled and resistant-necrotic. Necrotic is dominant to nonnecrotic in both susceptible and resistant phenotypes. The genes are inherited independently.
462 Inheritance of Light-Green Flower Color (gf) in Watermelon (Citrullus lanatus)
Authors: Kwon Young-Seok , Dane Fenny
Published: February 2019

Watermelon (Citrullus lanatus Thumb. Matsum. and Nakai) flower petals usually are yellow, but in watermelon line Kw-695, light-green flowers were detected. To study the inheritance of light-green flower color, Kw-695 plants were crossed with yellow-flowered Korean cultures `SS-4' and `Dalgona'. The resulting F1, F2, and reciprocal backcross generations were analyzed for flower color. Segregation ratios in the F2 and backcross to Kw-695 were 3 yellow: 1 light green and 1 yellow: 1 light green, respectively. Backcross generations to the yellow-flowered parents showed yellow flowers only. These results indicate that inheritance of the light-green flower character in Kw-695 is governed by a single recessive gene. We propose the gf gene symbol for the green flower trait. Kw-695 plants have large vines with large, light-green leaves. The plants are andromonoecious, have large, oval, bright yellow-green fruit with irregular dark-green stripes, bright yellow-orange, inedible flesh with very low sugar content (about 3.2 °Brix), and light-yellow seeds. The trait should be useful as a marker in watermelon breeding programs. Linkages between this trait and other genetic markers in watermelon will be investigated.
463 Understanding Genetics of Freezing Tolerance: Expression of Freezing Tolerance in the Interspecific F1 and Somatic Hybrids of Potatoes
Authors: Chen Y.-K. , Palta J.P. , Bamberg J.B.
Published: February 2019

Wild potato species provide a valuable source of genetic variability for the improvement of freezing tolerance in cultivated potato, Solanum tuberosum (tbr). However, breeding for freezing tolerance by using wild genetic resources has been hampered by contradictory results regarding the genetic control of this trait. Both dominance and recessiveness for this trait have been reported. To explore the genetic control of freezing tolerance, the expression of freezing tolerance was investigated in various interspecific F1 and somatic hybrids between hardy and sensitive species. In addition to 2 years of field evaluation, freezing tolerance before and after acclimation was characterized separately under controlled environments to dissect the two independent genetic components of freezing tolerance, namely nonacclimated freezing tolerance (NA) and acclimation capacity (ACC). The expression of freezing tolerance, including NA and ACC, was closer to that of hardy parent, sensitive parent, or approximate parental mean, depending on species combination. However, the expression of freezing tolerance tended to be greater when the hybrids contained more sets of chromosomes from the hardy parent than from the sensitive parent. The significance of hardy: sensitive genomic ratio was further supported by using sexual and somatic hybrids between tbr and S. commersonii (cmm) to achieve different genomic ratios without the confounding effect of species. Therefore, we propose that the hardy: sensitive genomic ratio is an important determinant for the expression level of freezing tolerance before and after cold acclimation.