bluuebunny/crossref_metadata_2025 huggingface dataset:
115 Performance of Various Apple Scion Cultivar/Rootstock Combinations and Postharvest Fruit Quality
Authors: Sindoni V. Maria J. , Matta Frank B.
Published: February 2019

Several cultivar/rootstock combinations were evaluated for overall performance in Mississippi. This study included postharvest fruit quality during storage as influenced by the various rootstocks. Parameters measured were fruit set, scion and stock trunk cross-sectional area, fire blight tolerance, fruit drop, and maturity indices such as fruit size, firmness, fresh fruit weight, soluble solids content, and juice pH. Cultivar/rootstock combinations were `Earligold'/EMLA 7, `Jonagold'/EMLA 111, `Improved Golden'/EMLA 7, `Improved Golden'/EMLA 111, `Scarlet Gala' /EMLA 7, `Jonafree'/Mark, `Macspur'/M 7A, `Royal Gala'/MM 111, and `Williams Pride'/M 7A. Cultivar and rootstock influenced fruit set. `Royal Gala', `Scarlet Gala', `Improved Golden', and `Earligold' showed maximum fruit set among the various cultivars. MM 111 and EMLA 7 rootstocks increased fruit set. Scion cultivars had the greatest trunk diameter on EMLA 111 and MM 111 and the smallest diameter on Mark. Scion cultivars on Mark and M 7A rootstocks showed less susceptibility to fire blight compared to MM 111 and EMLA 111. Cultivars on EMLA 7 showed moderate susceptibility to fire blight. Cultivars `Jonafree', `Williams Pride', `Macspur', and `Scarlet Gala' were least susceptible to fire blight compared to `Royal Gala'. The remaining cultivars were intermediate in susceptibility to fire blight. Fruit size, firmness, fresh fruit weight, soluble solids content, and juice pH were influenced by cultivar. `Jonagold' and `Williams Pride' produced the largest fruit, while `Jonafree' and `Macspur' yielded the smallest fruit. Total soluble solids were not influenced by cultivar and rootstock combinations. Sugar content of the juice increased as the apples matured and ranged from 12% to 14% among the cultivar/rootstock combinations. Firmness was influenced by cultivar but not rootstock. `Jonafree', `Macspur' had firm fruit, while fruit of `Scarlet Gala', `Williams Pride', and `Earligold' was not as firm. After harvest, the cultivars were stored at 2 °C for ≈4 months under controlled conditions and evaluated for soluble solids content, titratable acidity, pH, and firmness at monthly intervals. Overall, firmness, soluble solids content, and titratable acidity in all cultivars decreased with time in storage. `Improved Golden'/EMLA 7, `Royal Gala'/MM 111, and `Jonagold'/EMLA 111 maintained quality during storage, compared with the remaining cultivars/rootstock combinations, and had a longer storage life.
123 Quality and Shelf Life of Semi-savoy Spinach stored in Clamshell Containers
Authors: Kirkpatrick J.A. , Morelock T.E. , Howard L.R. , Dainello F.J.
Published: February 2019

Fresh-market spinach production has risen in the United States in the past few years as well as total value of the crop. Increased crop value may be attributed to more “value added” spinach products being produced and marketed. Public awareness of nutrition is rising due to more information being distributed concerning cancer prevention, antioxidants, and neutraceuticals. Spinach is high in the carotenoids beta-carotene and lutein, a known antioxidant for the prevention of age-related macular degeneration (AMD). It is also high in vitamins A, C, E, and folate, fiber, and the mineral iron. In this respect, spinach producers have an advantage over growers of salad vegetables such as lettuce. While this is an advantage, more innovative “value added” methods of marketing this product to the consumer are needed. A dark-green, semi-savoy spinach type developed at the Univ. of Arkansas was studied to determine shelf-life and storage capabilities of root cut plants in transparent clamshell containers. Plants were held at temperatures ranging from 1 to 6 °C. Leaf turgidity and visual characteristics were rated on a 1 to 5 scale. Acceptable characteristics and shelf-life of spinach stored in clamshell containers were seen up to 14 to 21 days when plants were stored at or near 1 °C. These results indicate that spinach packaged in transparent clamshell containers will maintain an acceptable shelf-life and could be beneficial to fresh market spinach producers.
127 Ethylene Production in Tomato Fruit in Relation to Postharvest Quality Deterioration
Authors: Abdul Hakim , Eija Pehu , Irma Voipio , Mohfeza Khatoon
Published: February 2019

Ethylene is produced by tomato fruit (Lycopersicon esculentum) at a rate that is dependent on fruit size, maturity stage, and adherence of calyxes. Production rate of ethylene declined with increased maturity stages. Small fruit produced higher ethylene compared to medium or large sizes. Ethylene production is positively correlated with rate of respiration, but not with visible pitting. Fruit stored with calyx produced less ethylene than those that were stored without calyxes.
131 Controlled Atmosphere Temperature Treatments for Disinfestation of `Bing' Sweet Cherry
Authors: Shellie Krista C. , Neven Lisa , Drake Steve
Published: February 2019

Phytosanitary restrictions for insect pests can interfere with the marketing of fresh sweet cherries (Prunus avium L.). The objective of this research was to compare the quality of controlled atmosphere temperature treated (CAT) sweet cherries to methyl bromide fumigated cherries and non-heated, non-fumigated control fruit. Two CAT doses were evaluated: a 25-min exposure to 47 °C (117 °F) that heated the cherry center to 46 °C (115 °F), and a 40-min exposure to 45 °C (113 °F) that heated the cherries to a center temperature of 44 °C (111 °F). These heat doses approximated a heat dose that provides quarantine security against codling moth (Cydia pomonella Lw.) and western cherry fruit fly (Rhagoletis cingulata Lw.). An atmosphere of 1 kPa oxygen and 15 kPa carbon dioxide was established inside the treatment chamber for 21 min prior to heating. The influence on fruit quality of hydrocooling prior to the CAT treatment, cooling after treatment, and 2 weeks of cold storage after treatment in air or controlled atmosphere was evaluated. Each CAT dose was replicated four times using freshly harvested, `Bing' sweet cherries acquired from similar grower lots. Quality attributes evaluated included: stem and fruit color, firmness, soluble solids concentration, titratable acidity, decay, and sensory evaluations. Hydrocooling prior to treatment, cooling method after heating and storage atmosphere had no significant influence on cherry quality after cold storage. The stem color of fumigated cherries was less green after storage than CAT treated cherries or untreated, control cherries. Cherries heated for 25 min were rated after cold storage by untrained panelists as similar to non-heated, non-fumigated control fruit. Heated cherries and methyl bromide fumigated cherries were less firm after cold storage than control fruit.
140 Ultrastructural Changes during the Senescence of Petals in Hibiscus syriacus L.
Authors: Kwon Hye Jin , Kwon Song , Kim Ki Sun
Published: February 2019

Five distinctive developmental stages were chronologically suggested. Cells at Stage I and II were essentially free of cytoplasmic or vacuolar abnormalities and the cytoplasm contained numerous electron-dense mitochondria with well-developed cristae. At Stage III, there were a localized dilation of mitochondria matrix and a partial-diluted cytoplasm in mesophyll cells. At Stage IV, characterized by high levels of fresh weight and osmolality, most mesophyll cells were seen to be ruptured, resulting in a general mixing of cell contents and diluting cytoplasm. It can be explained as an irreversible senescence phenomena that tonoplast in mesophyll cell was ruptured partly, corresponding to rapid increase in petal cell size and turgidity. Petal turgidity was due to an increase of content in soluble sugar. At Stage V, there was a loss of petal fresh weight. With a loss of turgidity, most mesophyll cells have collapsed completely. There were a notable plasmolysis in vasculature. The activity of protease in petals was found to increase between Stage II and III, and then decreased rapidly at Stage IV, resulting in the decrease of total protein content before senescence. Unexpectedly, there were stomata in hibiscus petals. Ultrastructural disorganization, like as a broken tonoplast, was observed in mesophyll cells at Stage IV. ABA and the stomata on petal might promote the disorganization. The final stages of senescence involved breakdown of cellular organization leading to hydrolysis of previously separated compartments. The cellular disorganization triggered during the flowers are still in the process of opening may be one of the earliest physiological signal that senescence is under way.
145 Water Deficit Stress Responses of Seven Tree Species Used in Urban Landscapes
Authors: Balok Coye A. , St. Hilaire Rolston
Published: February 2019

Plant development, leaf morphology, leaf cuticular wax content, and leaf water relations were determined for seven tree species exposed to consecutive cycles of drought. The objective of the experiment was to identify plant taxa suitable for landscapes prone to drought. On the day drought treatments began, plant development traits and leaf morphology varied among species. Leaf cuticular wax content was different among species and ranged from 0.053 mg·cm–2 in California white oak (Quercus lobata Née), to 0.200 mg·cm–2 in Texas red oak (Quercus buckleyi Buckl.). Was content in Bur oak (Quercus macrocarpa Michx.) and Shumard oak (Quercus shumardii Buckl.) averaged 0.105 and 0.11 mg·cm–2, respectively. At harvest, Texas red oak plants treated with drought had the highest root-to-shoot dry weight ratio which averaged 3.1. In contrast, plants of Arizona ash (Fraxinus velutina Torr.) and California white oak that were frequently irrigated had the lowest root-to-shoot dry weight ratio. Drought did not affect stem elongation, total lamina area, leaf dry weight, and specific leaf weight. Abaxial leaf surfaces of Arizona ash were the most pubescent and averaged1836 trichomes/cm2. Drought-stressed plants of golden rain tree (Koelreuteria paniculata Laxm.) had the most negative midday leaf water potential, which averaged –2.5 MPa. Plants of Chinkapin oak (Quercus muehlenbergii Engelm.) that were irrigated frequently had the least negative predawn leaf water potentials. Predawn leaf water potentials tended to be more negative for Arizona ash and golden rain tree than for the oak species. These results suggest that some species of oak might perform well in landscapes prone to drought.
149 Effects of Plant Growth Retardants on the Growth of Aerides japonicum Cultured in Vitro
Authors: Chung J.D. , Park Y.K. , Jee S.O. , Kim H.Y. , Cho M.S.
Published: February 2019

This experiment was conducted to identify the effect of various growth retardants on the growth of Aerides japonicum in vitro. Paclobutrazol was found the most effective retardant for reducing the leaf growth of seedling. Ancymidol and uniconazole also showed retarding effects on leaf growth of one, whereas Daminozide didn't. When growth retardants were added to culture medium, leaf length of seedlings was gradually shortened and leaf width became wider than that of control. However, root length was shorter and number of roots and root diameter were greatly increased. On the contrary, at 0.05 and 0.1 ppm uniconazole, growth of leaf and root were enhanced. It was showed that the possibility of using as an additive for good growth of Aerides japonicum seedling in vitro. The activity of GA-like substances was higher in the portion in which growth of seedlings were promoted. It was identified by anatomical observations that the number of stomata and thickness of cell layer in leaf were increased by treatment of retardants.
159 The Relationship between Actual Photosystem II Efficiency and Quantum Yield for CO2 Assimilation is Not Affected by Nitrogen Content in Apple Leaves
Authors: Cheng Lailiang , Fuchigami Leslie H. , Breen Patrick J.
Published: February 2019

Bench-grafted Fuji/M26 apple (Malus domestica Borkh) trees were fertigated with different concentrations of nitrogen by using a modified Hoagland's solution for 45 days. CO2 assimilation and actual photosystem II (PSII) efficiency in response to incident photon flux density (PFD) were measured simultaneously in recent fully expanded leaves under low O2 (2%) and saturated CO2 (1300 ppm) conditions. A single curvilinear relationship was found between true quantum yield for CO2 assimilation and actual PSII efficiency for leaves with a wide range of leaf N content. The relationship was linear up to a quantum yield of approximately 0.05 mol CO2/mol quanta, then became curvilinear with a further rise in quantum yield in response to decreasing PFD. This relationship was subsequently used as a calibration curve to assess the rate of linear electron transport associated with rubisco and partitioning of electron flow between CO2 assimilation and photorespiration in different N leaves in response to intercellular CO2 concentration (Ci) under normal O2 conditions. Both the rate of linear electron flow, and the rate to CO2 or O2 increased with increasing leaf N at any given Ci, but the percentage of linear electron flow to CO2 assimilation remained the same regardless of leaf N content. As Ci increased, the percentage of linear electron flow to CO2 assimilation increased. In conclusion, the relationship between actual PSII efficiency and quantum yield for CO2 assimilation and the partitioning of electron flow between CO2 assimilation and photorespiration are not affected by N content in apple leaves.
171 Changes of Carbohydrate Metabolism in Apple Leaves in Response to Sink-source Manipulation
Authors: Zhou Rui , Quebedeaux Bruno
Published: February 2019

In order to determine whether the changes in the demand for the transported carbohydrates in apple source leaves are associated with specific carbohydrate enzyme changes, we made source–sink manipulation by girdling or defoliation. The girdle was applied to side branches with several fully expanded leaves, and the defoliation was conducted by removing about 90% of source leaves in apple seedlings. 3-year-old apple (Malus domestica Borhk. cv. Gala) seedlings were grown in a 15/9-h light (≈700 μmol photons/m2 per s, 22 °C)/dark (18 °C) in the growth chamber. When the demand for transported carbohydrates from a particular source leaf is limited by girdling, carbohydrates including starch, sorbitol and sucrose accumulated in the source leaves, meanwhile girdling reduced net photosynthetic rates (Pn) dramatically from 12.8 initially to 4.6 μmol CO2/m2 per s over a 7-day period. When the demand for transported carbohydrate in the remaining source leaves was increased by defoliation, all carbohydrate levels decreased while Pn of individual leaves increased from 13.6 initially to a maximum of 19.8 μmol CO2/m2 per s after 7 days. These Pn changes in the carbohydrate depleted and accumulated leaves were due mainly to changes in the photosynthetic capacity as indicated by Pn-Ci curve measurements. The carbohydrate enzyme activities were also dramatically changed during the 7-day experimental period. The activity of aldose-6-phosphate reductase (E.C. 1.1.1.200), an important enzyme in sorbitol biosynthesis, increased significantly from 27.5 to 39.2 μmol/h per g FW in the carbohydrate depleted leaves while it remained unchanged in the girdled leaves, the activity of sucrose-6-phosphate synthase (SPS, E.C. 2.4.1.14), a key enzyme for sucrose biosynthesis, increased from 15.4 to 23.0 μmol/h per g FW in the depleted leaves and declined from 17.4 to 8.2 μmol/h per g FW in the girdled leaves, the activity of fructose 1,6 bisphosphatase (E.C. 3.1.3.11), another key enzyme for sucrose biosynthesis in non-Rosaceae species showed a similar pattern as SPS, ADPglucose-pyrophosphorylase (E.C. 2.7.7.27), a key enzyme for starch biosynthesis, decreased a small amount in the girdled leaves but increased markedly from 42.9 to 56.0 μmol/h per g FW in the depleted leaves. These results indicated the specific roles of the enzymes in the partitioning of carbon between sorbitol, sucrose and starch in apple source leaves.
176 Substrate on Apple Fruit Increased Sooty Blotch Incidence
Authors: Belding Robert D.
Published: February 2019

The potential mechanism of susceptibility of apple (Malus ×domestica Borkh.) fruit to sooty blotch due to carbohydrate leachates was examined. Fruit received applications of 0.5% apple juice to the fruit cuticle in order to mimic leachates. Nine cultivars of apple were selected from a variety block of potentially disease resistant breeding stock. Intact fruit on selected limbs received 0.5% apple juice applications on eight evenly spaced occasions during development. Trees received a minimal fungicide program only. Leachate samples from the fruit cuticles were collected monthly by immersion of whole, detached fruit in dH2O for 60 min. At harvest, fruit were evaluated for skin roughness, fruit rots, sooty blotch, sooty mold, flyspeck, and insect injury. Despite drought conditions, sooty blotch and sooty mold showed strong increases in disease intensity ratings, while flyspeck and skin texture damage showed moderate increases in intensity due to the dilute juice applications. Fruit rots and insect damage were unaffected by the juice applications.
195 Sexual and Vegetative Performance of Native and Cultivated Day-neutral Strawberries under Moderate and High Temperatures
Authors: Serce S. , Hancock J.F.
Published: February 2019

A common complaint with day-neutral strawberries is that they perform poorly in mid-summer heat. Since most modern day-neutral cultivars are derived from the same Fragaria virginiana ssp. glauca clone from Utah, we felt it prudent to search for alternate sources of day-neutrality that were more heat-tolerant. We compared the sexual and vegetative performance of nine F. virginiana clones from a wide range of environments including the Utah site, and four F. × ananassa day-neutral types (`Aromas', `Fort Laramie', `Ogallala', and `Tribute') under constant temperatures of 18, 22, 26, and 30 °C and 12-h days. `Aromas' and `Tribute' carry the Utah source of day-neutrality, while `Fort Laramie' and `Ogallala' are old cultivars that have a different, complex background. After a 4-week period of acclimation, we counted the number of crowns, inflorescences, flowers, stolons, and daughter plants that emerged over a 10-week period, and measured the dry weights of component parts. ANOVA tables revealed that temperature regime (T), genotypes (G), and T*G were significant for flower number (FLN) and total dry matter accumulation, while species and T*G were significant for daughter plant number (DPN). Mean FLNs across the four temperatures were 6.8, 3.7, 3.3, and 1.2, while mean DPNs were 0.7, 0.9, 0.7, and 1.8. F. virginiana clones averaged 3.8 FLNs and 1.8 DPNs, while the F. × ananassa clones averaged 4.1 FLNs and 0.2 DPNs. There was generally more variability among the F. virginiana clones than the F. × ananassa clones, but the F. × ananassa cultivars, `Fort Laramie' and `Ogallala', performed best at 30 °C. The Wasatch clone did not flower in any treatment, suggesting it is not day-neutral.
220 Growth of Evergreen Shrubs in Potting Mixes Made with De-inked Paper Sludge
Authors: Tripepi Robert R. , George Mary W.
Published: February 2019

De-inked paper sludge from a newsprint mill was evaluated as a substitute for sofwood bark in container media. Rooted cuttings of `Youngstown' juniper (Juniperus horizonatlis), Fraser photinia (Photinia × fraseri), and `PJM' rhododendron (Rhododendron) were planted in 3-L plastic pots that contained potting media amended with 0%, 20%, 40%, 60%, 80%, or 90% paper sludge and 80%, 60%, 40%, 20%, or 0%, respectively, bark (by volume). All mixes contained 10% sand and 10% peatmoss except for the 90% mix, which lacked peatmoss. After 19 weeks, plant heights were measured for photinia and rhododendron, but average plant width was measured for juniper. Shoot dry weights were also determined for all species. Juniper and photinia seemed to be the most tolerant of media amended with up to 40% paper sludge, whereas rhododendron was the most intolerant species. Shoot dry weights of juniper or photinia were similar for plants grown in media containing 40% or less paper sludge. Shoot dry weights of rhododendron plants grown in 40% sludge were 23% lower than those grown in 0% or 20% paper sludge, which were similar to each other. Plant heights followed similar trends to those of the shoot dry weights. With the exception of juniper, shoot dry weights and heights were drastically reduced if the potting mixes contained more than 40% paper sludge. These results demonstrated that de-inked paper sludge could be substituted for up to 40% of the bark in a container medium for two of the three species tested.
223 Precipitation Evaluation of Round- and Square-patterned Impact Sprinklers
Authors: Starr T. Scott , Klingaman Gerald L.
Published: February 2019

Two impact sprinklers, a traditional round-patterned design (Rain Bird Maxi-Bird) and a newly developed square-patterned design (Square Shooter) were tested under field conditions to compare the uniformity of their precipitation patterns. The Square Shooter sprinkler requires half as many sprinkler heads as the Rain Bird to cover the same area with head-to-head coverage. The Square Shooter sprinkler, with a coefficient of variation of 0.124, produced a more-uniform distribution of precipitation than the Rain Bird sprinkler, with a coefficient of variation of 0.215. Square Shooter also delivered water more accurately within the boundaries of the plot than Rain Bird, which had more of the total precipitation falling outside the plot area than Square Shooter. The new square-patterned design could allow installation of heads on only one edge of an area with the same, or better, uniformity of coverage as traditional perimeter installations.
226 Juvenile and Adult Growth Characteristics of Newly Planted Euonymus fortunei `Coloratus'
Authors: Sink Richelle A. , Einert Alfred E. , Klingaman Gerald L. , McNew Ronald W.
Published: February 2019

Euonymous fortunei `Coloratus' (Turcz.) Hand.-Mazz. (purpleleaf wintercreeper euonymus) is a groundcover species commonly grown in the landscape and known for its characteristic purplish-red color in the fall. This species is dimorphic, having both juvenile and adult forms present in established plants. Young plants, planted from 5.7-cm containers, were grown under full sun and 60% shade and evaluated for 1 year from May 1998. Four fertilizer treatments, up to four applications, were applied over the year. Data collected included the percent of adult and juvenile plants per plot, percent canopy cover, plant quality, and fresh and dry weights of pruned plant material and whole plants. Results showed that 73% of Euonymus planted in the shade were “adult-like” in form, while only 44% of Euonymus planted in the sun were “adult-like” in form. These results were analyzed with the percentage canopy cover determined for March, April, and May 1999 and showed no interaction of the two variables. By the end of the study, the mean percent of canopy cover was 77% under the shade and 74% under the sun. These values were not significantly different. While it appeared that the maturity of the plant did not effect the percent of groundcover coverage in a plot, the more mature or “adult-like” plants were visually undesirable within a plot of juvenile plants, and vice versa due to morphological differences.
245 Apples of Northeastern America
Authors: Khanizadeh S. , Groleau Y. , Cousineau J. , Thériault B. , DeEll J.R. , Beldica C. , Boddington H.
Published: February 2019

One of the major problems affecting apple trees in Eastern Canada is low temperature injury during the winter and spring. Although there have been many studies on the cold hardiness of apple trees, no survey has been done on winter injury in Québec orchards. A survey was conducted in 1995/1996 to identify factors responsible for apple tree mortality during the winter of 1993/1994 in Québec. Three-hundred-thirty (330) apple orchards were visited and information on more than 50 characteristics were evaluated via a questionnaire; including hardiness, end use, shelf-life, etc. A full report is available at http://www.pgris.com. A large diversity of cultivars and rootstocks was observed in the Québec orchards, and thus a database was created containing information for all cultivars evaluated and the collected agronomic characteristics. Some of the more important information, such as hardiness, end use, shelf-life, scab resistance, etc., along with 265 apple images, were put together as a poster. A copy of this poster is available from http://www.pgris.com.
264 Richards Function Applied to a Daily Additive and Iterative Approach to Model Rose Plant Stem Length Growth
Authors: Hopper Douglas A.
Published: February 2019

Height data were collected three times weekly between pinch and flowering to represent `Royalty' rose (Rosa hybrida L.) response to 15 unique treatment combinations of irradiation as photosynthetic photon flux (PPF: 50 to 300 μmol·m-2·s-1), day temperature (DT: 12 to 22 °C), and night temperature (NT: 15 to 25 °C) under constant growth chamber conditions. Combinations were determined according to the rotatable central composite design. A previous full quadratic model approach was compared with a revised approach using a nonlinear Richards function derivative form. This allowed a dynamic change of parameter values for each daily growth iteration by computer. The Richards function assumes nonconstant daily growth rates are proportional to current size; Euler integration enabled additive accumulation of these values. Ratios of the growth constant (k) to the theoretical catabolic constant (m = v+1) caused flexible changes in the growth curve, which were compared with the previous quadratic approach.
281 Impact of Plant Population, Nitrogen, and Variety on Early Fresh-market Sweet Corn Quality
Authors: Rangarajan Anusuya , Ingall Betsy A. , Orfanedes Michael S.
Published: February 2019

Early fresh-market sweet corn expressed concern is prone to variability in ear length and quality due to uneven germination rates in cooler soils, smaller plant size of early corn, and single ear per stalk trait of early varieties. In an informal survey of current practices, growers reported using in-row spacings between 0.5 and 0.25 m (0.76 m between rows) for their first bare-ground corn, representing a range of plant populations from 86,000 to 43,000 plants/ha. However, no information had been gathered on the impacts of these various in-row spacings on early corn ear length and overall quality and how different sweet corn types (se, sh2, sweet breeds) might respond to these spacings under cool conditions of early spring. Four trials were conducted over the last 2 years, in upstate New York, examining three sweet corn types, five plant populations, and two nitrogen sidedress rates for effect ear length, quality, and uniformity. In general, results thus far indicate that all three parameters can influence ear quality and variability. Among treatments, ear length varied by up to 1 cm. The variety `Sweet Symphony' was less affected by high populations than `Temptation'. In 1998, no difference in ear length due to spacing was found. It is suspected that the warm spring in 1998, coupled with adequate moisture, reduced plant stress during early growth. Higher nitrogen sidedress rates reduced variability of early season corn, at all populations. In 1999, plant population was found to be the most important factor affecting ear physical characteristics.
286 Effects of Different Mulching and Tillage Systems on Soil Water Retention Under Drought Conditions in a Tomato Production System
Authors: Swenson Joyce A. , Walters S. Alan , Schmidt Michael E. , Chong She-Kong
Published: February 2019

Water management is often the key to successful vegetable culture. Various mulching/tillage systems are often utilized in tomato production, depending upon the available resources of a particular grower, to achieve better water use efficiency. A study was conducted to compare six different mulching/tillage systems to observe the influence of these systems on soil water retention as well as on `Fabulous' tomato (Lycopersicon esculentum Mill.) production. Winter ryegrass and wheat were the cover crops utilized and were mowed with the following six treatments then applied: 1) Conventional tillage (CT), 2) black plastic over conventional tillage (BP), 3) no-till with cover crop sprayed with Glyphosate prior to transplanting (NT-GLY), 4) strip-till with cover crop sprayed with Glyphosate prior to transplanting (ST-GLY), 5) no-till in which cover crop was mowed periodically during the growing season (NT), and 6) strip-till with cover crop mowed periodically during the growing season (ST). This test was conducted under severe drought conditions (45.4 mm of rain from 1 July to 30 Sept. 1999) with plants receiving no supplemental water via irrigation at any time throughout the study. Soil moisture was measured periodically throughout the growing season at a depth of 20 cm; soil and mulch surface temperatures were taken at similar timings as soil moisture. Soil moisture levels during the growing season indicated different patterns of water depletion when comparing the six treatments. There was no significant difference between the winter rye and wheat with respect to water depletion or tomato yields. Lower early tomato yields under NT, ST, NT-GLY, and ST-GLY indicate that cooler soil conditions, while aiding in the retention of soil moisture, delay early tomato production when compared to the warmer soil conditions found under CT and BP. Results also indicate that late season harvests under NT and ST systems produce predominantly cull fruits with a high incidence of blossom-end rot. The NT-GLY and ST-GLY systems tended to produce comparatively lower levels of cull fruit and blossom-end rot in late season harvests than any of the other six treatments.
305 Effects of Electrical Conductivity (EC) and Its Diurnal Changes in Nutrient Feedings on Fruit Yield and Quality of Greenhouse Tomato Grown in Rockwool
Authors: Hao Xiuming , Papadopoulos Athanasios P.
Published: February 2019

Poor tomato fruit quality in summer time (soft fruit, cracking, and russetting) is a major greenhouse production problem in North America. To improve tomato quality and yield, especially under summer conditions, four EC treatments were applied to a tomato crop grown in rockwool in summer and fall of 1999 at the Greenhouse and Processing Crops Research Centre, Harrow, Ont., Canada. The four fertigation solution EC treatments were 1) constant low EC at 2.54 mS·cm-1, 2) constant high EC at 3.82 mS·cm-1, 3) diurnal EC variation (1 to 5 mS·cm-1) with a 24-h average of 2.54 mS·cm-1 and 4) diurnal EC variation (1 to 7 mS·cm-1) with a 24-h average of 3.82 mS·cm-1. For diurnal EC variation, the plants were fed with low EC in the morning and around noon, and high EC in the afternoon and night. High EC (3.82 mS·cm-1, constant or 24-h average for diurnal variation) treatments, in comparison to the recommended EC (2.54 mS·cm-1) treatments, improved tomato fruit quality by reducing fruit cracking, and increasing percentage of grade #1 fruit, fruit firmness, soluble solid and dry-matter content. However, the constant high EC treatment resulted in smaller fruit size and lower yield. Diurnal EC variation with a high EC average (24-h average: 3.82 mS·cm-1) did not reduce fruit size and yield, and reduced fruit russetting. Therefore, a diurnal fertigation EC variation strategy-supplying low EC solution in the morning and noon and high EC solution in the afternoon and night, with an overall 24-h average of 3.82 mS·cm-1, may be used to improve tomato fruit quality.
343 Effects of Jiffy Forestry Peat Pellets on Rooting and Subsequent Field Performance of Stem Cuttings of Loblolly Pine
Authors: LeBude Anthony V. , Blazich Frank A. , Goldfarb Barry
Published: February 2019

Experiments conducted in January (hardwood cuttings) and June (softwood cuttings) 1998 compared rooting and root dry weight (DW) of stem cuttings of three full-sib families of loblolly pine (Pinus taeda L.) rooted in Jiffy forestry peat pellets and Ray Leach Super Cells. Ray Leach Super Cells (vol.= 162 cm3) served as the control and contained a medium of 2 peat: 3 perlite (v/v). Pellet sizes used were 25-65, 30-65, 36-65, 36-75, 42-65, 42-80, and 50-95 (dry diam.-expanded height in mm). Cuttings were taken from hedged stock plants and rooted for 12 weeks under mist in a humidity-controlled greenhouse. Following evaluation for rooting in the June experiment, ≈500 rooted cuttings in pellets and Ray Leach Super Cells were field-planted in eastern Georgia in December 1998 to study the effect of pellet size and cutting development on first-year field growth. Rooting percentages in January for hardwood cuttings rooted in pellet sizes 42-80 (36%) and 50-95 (57%) were less than the control (83%). Root DW for each pellet size was less than the control. Rooting percentage in June for softwood cuttings rooted in pellet size 36-65 (77%) was greater than the control (64%) whereas rooting percentages for cuttings rooted in pellet sizes 42-80 (50%) and 50-95 (52%) were less than the control. Root DWs for cuttings in pellet sizes 25-65, 30-65, 36-65, and 42-65 were less than the control. Field performance data will be presented.
356 Composition of Leafy Greens as Affected by Season and Conventional or Organic Fertilization
Authors: Gent Martin P.N.
Published: February 2019

Leaf tissue composition may depend on season and method of fertilization. Lettuce and spinach were grown in spring, fall, and winter in unheated high tunnels using organic or conventional fertilization. The root medium was either perlite fertilized with a nitrate-based complete soluble fertilizer, or leaf compost/perlite 1:1 v/v fertilized with cottonseed meal. Growth rate did not differ due to the method of fertilization, but specific leaf area was 10% greater with compost. Growth in compost raised the concentrations of total reduced nitrogen, phosphate, and potassium in both species. Effects of season were factored with a 3rd-order polynomial in Julian day. Nitrate, total phosphorus and potassium varied with season. Interaction of effects of season and fertilization were only significant for total reduced nitrogen and phosphate in leaves of lettuce. The difference in nitrogen due to fertilization was larger in fall harvests than at other times of year. There was a similar, but nonsignificant, trend with time for total reduced nitrogen in spinach. Differences in nitrate due to fertilization were small, compared to those of reduced nitrogen. The same seasonal trend in potassium was seen in both species, and for both methods of fertilization. Concentrations were highest in spring and lowest in fall.
362 Balanced Nutrient Management in Citrus Grown in Acid Red Soils of Southeast China
Authors: Yang X.E. , Lin X.Y. , Zhang Y.S. , Stover E.W.
Published: February 2019

Citrus is a major fruit crop in the acid red soils (Ultisol) of hilly areas in Southeast China. These soils are normally deficient in P, K, and other elements. Integrated nutrient management is important for sustainable production of citrus in these areas. In this study, a systematic approach was used to identify the limiting factors for plant growth, using sorghum as a test species. Long-term field experiments were conducted with seven different P and K supply levels to determine optimal application rates for citrus (cv. Ponkan), following alleviation of other limiting factors. The primary nutritional limitations to plant growth in red acid soils included: severe deficiencies in N, P, and K, and moderate deficiencies in Ca, Zn, and B. With increasing application of P and K to field soil, N concentrations in citrus leaves decreased up to 60% due to dilution from increased growth, whereas P and K concentrations increased 2-3 fold. After 2 years of fertilizer application, the N: P: K ratio in leaves reached 1:0.5:1 for the optimal P and K treatment. The available P and K in the soils, measured after harvest each year, increased with increasing P and K application rates. However, within each treatment, increase in P and K with additional years of fertilization was modest. Citrus fruit yields generally increased with increasing P and K and reached a maximum at P and K rates of 125 kg P2O5/ha and 500 kg K2O/ha. In 3 years of successive field experiments, the highest net income was obtained by a balanced NPK fertilization practice using N: P2O5: K2O input of 450: 125: 500 kg/ha per year.
376 Relationship of Bract Boron Content and Boron Application to Bracts Necrosis of Poinsettia
Authors: McAvoy Richard , Bible Bernard
Published: February 2019

One factor in the development of poinsettia (Euphorbia pulcherrima Willd. ex Klotzch) bract necrosis is plant nutrition. Twenty poinsettia cultivars were grown as 15-cm single-pinched plants in Metro mix 510 with standard commercial practices for irrigating, fertilizing, and pest control. Seventy days after initial anthesis, plants were harvested and the number of necrotic and healthy bracts recorded. Mineral nutrients in bract margins were determined. The only nutrient that had a significant relationship to incidence of bract necrosis across the 20 cultivars was bract B content (R2=49.5%, P< 0.001). This suggests that cultivars with lower bract B content are more susceptible to bract necrosis. Using `Supjibi' plants grown in the Metro mix 510, we applied topical sprays of B (0, 4, or 8 mm) weekly during bract development or once at initial anthesis (8 mm). Also a weekly drench treatment of B (10 mm) was applied initially at bract color change and continued for 2 more weeks. By 42 days after initial anthesis, all B treatments averaged together reduced incidence of bract necrosis from 33.1% for controls to 10% for plant receiving B treatment. The B drench treatment resulted in leaf scorching and there was some leaf tipburn with the 4 and 8 mm B weekly sprays. The single spray (8 mm B) treatment at initial anthesis caused no injury. Although B sprays are not a replacement for Ca sprays as a control for bract necrosis, the results suggest a role for B in the etiology of bract necrosis.
380 Differential Responses of Container-grown Ornamental Foliage Plants to Silicon Application
Authors: Chen Jianjun , Caldwell Russell D. , Robinson Cynthia A. , Steinkamp Bob
Published: February 2019

Silicon (Si) is the second most-abundant element in soils, and its concentration in soil solution ranges from 0.1 to 0.6 mm, which is the same concentration range as some of the major nutrient elements such as calcium, magnesium, phosphorus, and sulfur. Increasing evidence has recently suggested that Si plays important roles in improving plant growth. However, little information is available on Si effects on container-grown ornamental plants, particularly since most are grown in soilless media where Si sources are greatly limited. The objectives of this research were to evaluate Si absorption and translocation in diverse container-grown ornamental plants and to determine whether Si absorption could improve plant growth. Liners from 39 plant species were potted in peat and pine bark-based soilless media and grown in a shaded greenhouse. Plants were fertigated with a Peter's 24–8–16 water-soluble fertilizer containing 0, 50, and 100 mg·L–1 of Si. Once marketable sizes were reached, plants were harvested and fresh and dry weights determined; Si and other nutrient elements in roots and shoots were measured. Results indicated that 32 of the 39 evaluated species were able to absorb Si, with large quantities further transported to shoots. Of the 32 Si-responsive species, 17 showed significant dry weight increases, whereas the other 15 only exhibited Si absorption and translocation with no apparent growth responses. The seven non-responsive plant species showed no significant increases in neither Si absorption and translocation, nor dry weight.
387 A Website for Evaluating Postproduction Quality of Parade™ Roses
Authors: Leonard Ria T. , Nell Terril A. , Hoyer Lars , Barrett Jim E. , Clark David G.
Published: February 2019

Postproduction evaluation trials have been developed in North America and Europe to test postproduction performance of potted roses from individual growers. The results of the trials have been compiled on the “Roses On The Web” Website (www.parade.dk). Roses on the WEB is a cooperative project between Poulsen Roses ApS, Denmark, the Danish Institute of Agricultural Sciences, and the Univ. of Florida. The goal of the Website is to provide growers participating in the evaluation trials a quick and easy way to obtain results on the postproduction quality of their roses. Plants receive 4 days of simulated transport, sleeved in a box in darkness at 16 °C. After transport, plants are maintained at 20 °C at 8 μmol·m–2·s–1 for 12 hours/daily. Relative humidity is maintained at 55% ± 5%. To determine quality, several parameters are recorded at day 0 (day of arrival), 11, 18, 22, and 28. The recordings include the number of open and damaged flowers and buds, percentage of damaged leaves, and the presence of disease and pests. Based on the results of all the measurements, each plant is given a postproduction rating or index, indicating quality. Results from each trial are tabulated and stored on the Website. Growers are able to view their results by entering a password. Growers can evaluate their quality over time and are also able to compare their quality with other growers. Many quality problems are manifested in the postproduction environment and can often be directly related to incorrect greenhouse conditions and/or cultural practices. “Roses On The Web” is a tool that provides quick, up-to-date information that can be crucial to the success of a grower. Differences in quality were found based on grower, time of year and variety.
398 Three Years of Tomato Gas Exchange Response to Nitrogen Sources at Fruiting
Authors: Whitehead Wayne F. , Singh Bharat P.
Published: February 2019

The purpose of this 3-year study was to compare organic and inorganic N sources for promoting gas exchange (GE) in tomato at fruiting. Measurements of transpiration (E), photosynthesis (Pn) and internal leaf CO2 concentration (Ci) are reported. The following winter–spring fertility treatments were applied using randomized complete block design with four replications: 1) 0 N winter–0 N spring, 2) 0 N winter–90 kg N/ha spring, 3) 0 N winter–180 kg N/ha spring, 4) 0 N winter+abruzi rye–0 N spring, 5) 0 N winter+hairy vetch–0 N spring, and 6) 0 N winter+crimson clover–0 N spring. In spring of 1996, 1997, and 1999, `Mountain Pride' tomatoes were transplanted in all plots. Maximum E (14.3 μmol·m–2·s–1), Pn (22.8 μmol CO2/m2 per s), and Ci (352.2 μL·L–1) occurred in 1997, 1996, and 1999, respectively. In general, E was affected mostly by treatments 2, 3, 5, and 6 and Pn by treatments 2 and 5, while treatments 1 and 4 affected Ci the most. Results indicate that N from both legumes and synthetic fertilizer enhanced GE of tomato similarly.
411 Effect of Compost and Mineral Fertilizer Applications on the Sensory Quality of Basil (Ocimum basilicum L.)
Authors: Radovich T.J. , Cavaletto C.G. , Valenzuela H.R.
Published: February 2019

The sensory quality of fresh basil (cv. Sweet Italian) was evaluated to determine if compost or mineral fertilizer applications affected flavor and aroma intensity. The four treatments, arranged in a randomized complete-block design with three replications, were: compost applied at 50 t·ha–1; compost applied at 200 t·ha–1; mineral N applied at 110 kg·ha–1; and a control receiving no amendment. Leaves from the first four nodes of young shoots were used in the evaluation. Twelve trained panel members scored samples of three leaves from each treatment for aroma and flavor intensity using a linear scale, converted to a scale of 1–10 where 1 = much less intense than a reference sample (control), and 10 = much more intense than the reference. No significant difference between treatments was found in flavor intensity. Significant difference between treatments in aroma intensity was found. Aroma scores were highest in samples from the compost and synthetic fertilizer treatments, and lowest in those from the control. Scores for aroma from the compost and synthetic fertilizer treatments were similar to each other. Aroma intensity increased with increased rate of compost application. No significant correlation was found between aroma intensity and plant tissue N content, sap NO3– levels, or yield.
418 Results of an Ornamental Horticulture Survey Conducted at High Schools in Illinois, Iowa, Minnesota, and Wisconsin
Authors: Compton Michael E.
Published: February 2019

Fifty high schools were surveyed in northwestern Illinois, northeastern Iowa, southeastern Minnesota, and Wisconsin to determine the number of students interested in pursuing a horticulture degree at a 4-year university. Students were asked several questions pertaining to horticulture. About 45% of our surveys were returned. Of the 451 surveys received, about 47% of the high school freshman, sophomore, junior, and seniors indicated that they were interested in horticulture. About 41% of the students interested in horticulture wanted to work in landscaping, 20% greenhouse, 14% florist shop, and 7% in turfgrass management. About 70% of the students indicated that they wanted to own and operate their own horticultural business. Almost 53% of the students indicated that they would prefer an emphasis/minor in Agribusiness or Business Administration compared to plant and soil science (19%), biotechnology (14%), plant breeding and genetics (13%), or comprehensive horticulture (1%) in combination with their horticulture degree. The above information was used by our School of Agriculture and Depts. of Biology and Business and Accounting to develop a major in Ornamental Horticulture.
424 A Comparison of Techniques Used for Determining Freezing Injury on Two Apple (Malus × domestica Borkh.) Cultivars: Liberty and RedMax
Authors: Garcia M.E. , Boccuzzo Linda A.
Published: February 2019

Hardiness testing of the wood of deciduous fruit trees has been conducted using a variety of techniques. In our studies, the objective was to determine an efficient method of determining freezing injury for apple (Malus × domestica Borkh.) wood. We tested 1-year old wood of two cultivars: Liberty and RedMax. The wood was tested over the course of 2 years (1998 and 1999). Collection began in the late fall and continued throughout the winter (until it was determined full hardiness had been achieved) and then again in the early spring. The wood was cut into 1-cm sections and frozen. The artificial freezing was conducted in an ethanol bath, with the temperature lowered at 5 °C/h. Samples were removed in 3-min intervals. After freezing, the wood was acclimated to 4 °C for 12 h. Three tests were conducted to determine the hardiness/injury to the tissues. The tests used were: discoloration, callus growth and vital staining (with 2,3,5-triphenyltetrazolium chloride). This was a split block design with samples collected randomly from each tree. Four replicates (12 trees) of each cultivar were tested. Results showed that the callus test predicted the same LT50 as the other two tests, discoloration and vital staining. Discoloration was not easy to differentiate and was the most time-consuming. The callus grown by the apple wood was easily formed and distinguished. The callus test does not require the tetrazolium stain; therefore, one less step was needed in comparison to the vital staining test. This reduced testing time by over 6 h.