bluuebunny/crossref_metadata_2025 huggingface dataset:
Dormancy and Premature Emergence of Hippeastrum
Authors: Kuehny Jeff S. , Miller William B.
Published: February 2019

The majority of Hippeastrum bulbs sold in the U.S. market are shipped from other countries. The shipping time and temperature varies by the country that the bulbs are shipped from and the storage time and temperature also varies by the company that packages the bulbs for retail sale. These packaged bulbs then sit on a shelf until they are purchased and forced by the consumer. These various storage times and temperatures can affect the longevity after packaging (premature emergence) and quality of the finished plant. The objectives of this research were to determine the effects of various storage temperatures and durations on emergence and forcing of Hippeastrum hybrids. Bulbs were stored at temperatures of 5, 9, 13, 21, and 29 °C for 6, 9, 12, and 15 weeks after which time one set was stored at 21 °C (packaged display temperature) and the other set forced in the greenhouse. Emergence of leaves and buds when stored at the 21 °C display temperature and during greenhouse forcing varied by specific hybrid according to storage duration at 5, 9 and 13 °C. Storage at 21 and 29 °C resulted in only leaf emergence and no flower bud emergence during the 21 °C display temperature and greenhouse forcing. Storage at 5 and 9 °C generally resulted in slower leaf emergence and quicker bud emergence. Results from this research can be used to help determine the best storage times and temperatures for preventing premature emergence of Hippeastrum based upon previous shipping times and temperatures.
The Effects of Root Zone Temperature and Limestone on pH and Electrical Conductivity on New Guinea Impatiens `Celebration Orange'
Authors: Welles Melanie L. , Hartley David E. , Newman Steven E.
Published: February 2019

The purpose of this experiment was to examine the effects of various root-zone temperatures and pH on Impatiens ×hybrida, New Guinea impatiens `Celebration Orange.' Greenhouse growers need to be cognizant of the root-zone medium pH, as New Guinea impatiens are sensitive to nutrient toxicities at low pH. It is thought that limestone at low root-zone medium temperatures is not quickly activated, leading to toxicities. The objectives of this project were to determine: the effect of root-zone medium pH on foliar symptoms of iron and manganese toxicity; and the effective rates and grind size of limestone on root-zone medium pH. Various rates of limestone and different grind sizes were incorporated into a sphagnum peat moss-based medium at a range of temperatures. This experiment used a two-way thermogradient plate to maintain varying, but stable root-zone medium temperatures, ranging from 12 to 42 °C. Plant growth as well as root-zone medium pH was monitored. Changes in root-zone medium pH were monitored over time. Results indicated that the addition of moderate or high rates of limestone, 6 or 3 kg·m-3, provided stable root-zone media pH over the course of time. Both limestone grind sizes at 325 and 100–200 mesh provided satisfactory starting and ending pH values for healthy New Guinea impatiens growth, especially between the root-zone temperatures of 30 and 18 °C. Higher and lower temperature extremes inhibited root growth, resulting in lower quality plants.
Plant Water Use Differs among Three Mature Highbush Blueberry Cultivars
Authors: Yang Wei Qiang , Bryla David , Strik Bernadine
Published: February 2019

The water use of three mature highbush blueberry cultivars was determined during the growing season by using TDR technology. A combination of four buriable TDR waveguides at 6-, 12-, 18-, and 24-inch depth and two surface waveguides 6- and 18-inch length were installed in a 60-acre commercial `Bluejay', `Bluecrop', and `Jersey' blueberry field with four replications for each cultivar. The reference evapotranspiration (ETo) was obtained for each cultivar from three weather stations located in the vicinity of replicated waveguides. Soil moisture data were collected every 3-5 days from April to the end of September. The average daily crop evapotranspiration (ETc) was significantly different at different plant developmental stages among three cultivars; the highest daily plant water use was during the fruit development stage for all three cultivars. The crop ETc for `Bluejay' and `Elliott' can be as high as 0.35 inches per day and average 1.5 to 2 inches per week during the summer. The estimated crop coefficients at bloom, fruit development, harvest, and postharvest are 0.90, 1.51, 1.05, and 1.05 for `Bluejay'; 0.84, 1.11, 0.99, and 1.23 for `Bluecrop'; and 0.94, 1.30, 1.39, and 1.17 for `Jersey', respectively. The peak water use coincides well with the advancement of fruit maturity, suggesting irrigation scheduling should differ among early, mid, and later season highbush blueberry cultivars.
Activity of Cell Wall-associated Enzymes in Cold-stored Tomato Fruit
Authors: Rugkong A. , Rose J.K.C. , Watkins C.B.
Published: February 2019

Tomato fruit (Solanum lycopersicon L.) can develop mealiness and enhanced softening when exposed to chilling temperatures during storage, but the involvement of cell wall-associated enzymes in chilling injury development is not well understood. To study this aspect of injury development, we have exposed breaker stage tomato cv. Trust fruit to a chilling temperature of 3 °C for 0, 7, 14, and 21 days followed by storage at 20 °C for 12 days. Ethylene production was not affected by storage except after 21 days, where production was greater at 20 °C. Exposure of fruit to chilling temperatures delayed the ripening-related color change (chroma and hue) and initially increased compression values, but percentage of extractable juice was not affected consistently. Increased polygalacturonase activity during ripening was reduced by about 50% after 7 days at 3 °C, and further inhibited with increasing storage periods. In contrast, the activities of pectin methylesterase and α-galactosidase were not significantly affected by the cold treatments. β-Galactosidase activity was greater in all chilled fruit compared with fruit ripened at harvest, whereas endo-β-1,4-glucanase activity was lower after 21 days at 3 °C. These results will be compared with equivalent changes in the activities of cell wall enzymes that are associated with wooliness development in chilling-injured peach fruit.
Experiential Partnerships Enhance Student Learning during Construction of Campus Gardens
Authors: Stearns Dan , McGann Martin
Published: February 2019

Students in a Penn State landscape contracting class were involved in the construction of the Hintz Alumni Gardens from Nov. 2002 through Apr. 2005. While campus construction projects have long been a part of the curriculum, the scope and complexity of the Alumni Gardens created unique challenges and opportunities for learning. The project was broken into phases that were installed over a 3-year time period. Professional staff from the University's Office of Physical Plant, including landscape supervisors, masons, electricians, plumbers, and carpenters, were integrated into course activities. They worked with students during planning phases and throughout field operations. Students learned first-hand from experts who had years of experience in their discipline. In addition, three contractors were hired to lead activities in specific areas of bridge construction, pond construction, and irrigation installation. This unique collaboration exposed students to a wide variety of construction techniques, and gave them experience in project management, scheduling, and procurement. The end result of their efforts was a successfully completed garden installation.
Undergraduate Involvement in Master Planning the Anishinabe Culture and Wellness Center
Authors: Midden Karen Stoelzle , Hamley Mark
Published: February 2019

A cooperative project between Turtle Mountain Tribal Community College and Southern Illinois University (SIU) completed a master plan for the Anishinabe Culture and Wellness Center in Belcourt, N.D. The project involved four SIUC undergraduate landscape horticulture students and the researcher visiting the 100-acre site, students and faculty of the Community College, as well as residents of the reservation. The purpose of the project was to: 1) explore developing a distance learning landscape horticulture program as a model project; 2) offer hands-on learning experience for the undergraduates; and 3) develop a master plan for a cultural, wellness, and environmental educational center. Developing the master plan involved four stages conducted by SIUC and Turtle Mountain participants. This included an inventory of the site and surrounding area, visiting classes at Turtle Mountain Tribal College, and interviewing numerous people from the reservation. An analysis was completed to review desired activities, such as a native plant garden, medicine wheel garden, pow wow site, and an outdoor kitchen, in relation to physical and observed features of the site. Environmental concerns, including water quality of the lake, were also addressed in the analysis. A master plan was completed after design concepts were explored. Future goals to complete the Anishinabe project include educational workshops and seeking funds to implement the master plan. Participants felt that the learning exercise for this model project was rewarding and successful. Therefore, SIUC and Turtle Mountain will continue to develop distance learning opportunities for students and potentially invite other tribal colleges with an interest in landscape horticulture to be involved.
Shoot Preformation and Neoformation in Pistachio: Influences on Bearing Habit and Yield Components
Authors: Spann Timothy , Beede Robert H. , Weinbaum Steven A. , DeJong Theodore M.
Published: February 2019

Rootstock significantly alters the pattern of shoot growth of pistachio (Pistacia vera) cv. Kerman. Trees grown on P. atlantica typically produce a single flush of spring growth, whereas trees on P. integerrima selection PGI and P. atlantica × P. integerrima selection UCB-1 can produce multiple flushes during the season. We have shown that the spring flush is entirely preformed in the dormant bud for all three rootstocks, but later flushes are neoformed, that is, nodes are initiated and extended during the same season. Shoots producing both preformed and neoformed growth have lower yield efficiency than those producing only preformed growth. Additionally, yield components of the crop from shoots with both preformed and neoformed growth was different than for shoots producing only preformed growth. However, these differences do not appear to be significant at the whole tree level. These data suggest that neoformed growth can both compete with fruit growth for available resources (lower yield efficiency) and act as an additional source (altered yield components), depending on the factor being measured. Controlling neoformed growth may potentially increase pistachio yield through a shift to the more efficient preformed shoots while at the same time lowering orchard maintenance costs by reducing required pruning. We have data to indicate that regulated deficit irrigation and new pruning techniques may be viable methods for controlling neoformed growth in pistachio without affecting yield.
Cloning and Characterization of Five MADS Box Genes in Peach (Prunus persica)
Authors: Xu Yong , Wu Fan , Ma Rong-Cai
Published: February 2019

MADS box genes regulate most of the development processes in plants. Studying peach MADS box genes will provide insights into its flower and fruit development. Five MADS box cDNAs with complete coding regions were cloned in this study. PpMADS2 cDNA is 1116-bp long. RT-PCR analysis indicated that PpMADS2 is expressed in leaf, flower, fruit, and nutlet. PpMAD4 cDNA is 824-bp long, which is the homologue of Agamous. RT-PCR analysis indicated that PpMADS4 is expressed in the two inner parts of flower, fruit, and nutlet; and was absent in leaf and the two outer parts of the flower. This expression pattern is similar to that of Agamous gene in A. thaliana. PpMADS4 could promote the flowering process in A. thaliana tested by genetic transformation. PpMADS5 cDNA is 873-bp long, which is the homologue of SEP3. RT-PCR analysis indicated that PpMADS5 is expressed in the three inner parts of flower, fruit, and nutlet; and was absent in leaf and sepal, similar to the expression pattern of SEP3 gene in Arabidopsis. PpMAD6 cDNA is 1037-bp long, which is the homologue of FUL. RT-PCR analysis indicated that PpMADS6 is expressed in leaf, sepal, petal, carpel, and fruit; and was absent in stamen and nutlet. PpMAD7 cDNA is 1147-bp long, which is the homologue of SEP1. RT-PCR analysis indicated that PpMADS7 is expressed in the four parts of flower and fruit, and was absent in leaf, stamen, and nutlet. Furthermore, two SSRs were identified in the 5' UTR in the two MADS box genes, PpMADS2 and PpMADS7, respectively. The SSR in PpMAD2 was more polymorphic than that in PpMADS7 in the 39 Prunus accessions collected.
Linkage of RAPD and SSR Markers to Thorniness and Floricane Fruiting in Blackberry
Authors: Stafne Eric , Clark John , Lewers Kim
Published: February 2019

Molecular markers have been used previously to identify linkages to important traits of interest. In this study two marker types, randomly amplified polymorphic DNA (RAPD) and simple sequence repeats (SSR), were used to find molecular markers linked to two morphological traits in blackberry (Rubus L. subgenus Rubus). Thorniness and floricane fruiting are both qualitative, recessive traits that are inherited tetrasomically. A cross of `Prime-Jim'® × `Arapaho' was made to create a population that segregated for the two traits. A random sample of 98 plants from a population of 200 were assayed to find molecular markers that co-segregate with the two traits. Three putative markers were identified for the floricane fruiting trait (two SSRs and one RAPD; χ2 = 4.09 to 9.99, P < 0.001 to 0.043). Five potential RAPD markers were found for the thorny trait (χ2 = 3.88 to 10.23, P < 0.001 to 0.048). Identification of markers linked to these traits could potentially be useful in marker-assisted selection.
A Natural Pentaploid Strawberry Genotype from the Changbai Mountains in Northeast China
Authors: Jiajun Lei , Yuhua Li , Guodong Du , Hanping Dai , Mingqin Deng
Published: February 2019

A natural strawberry genotype, `Jilin 4', was collected from the Changbai Mountains located in Gongzhuling Region, Jilin Province, Northeast China. It was identified as a pentaploid (2n = 5x = 35) by counting the chromosomes of the root-tip cells. Natural pentaploid strawberries have not been reported as originating in China or outside of California in the U.S. Jilin 4 was the most vigorous genotype among representatives of all 15 wild species of Fragaria and more than 60 cultivars of F. ×ananassa in a common garden. The size of its flowers and anthers were similar to those of cultivars and it produced abundant runners. The pollen was viable, but the pistils were sterile. It appeared to be drought and cold tolerant, but showed symptoms of local virus infection. There are three possible origins of Jilin 4, which are discussed in this report.
Volatile Floral Chemistry of Heliotropium arborescens L. 'Marine'
Authors: Kays Stanley J. , Hatch Jason , Yang Dong Sik
Published: February 2019

Selection emphasis on cyme size and flower color of Heliotropium arborescens L. has led to cultivars with diminished floral fragrance. As a preliminary inquiry into the fragrance chemistry of the species, we identified 41 volatile compounds emanating from the flowers of 'Marine' via isolation (Tenax trapping) and gas chromatography–mass spectrometry. The majority of the volatile compounds emanating from the flowers were terpenes (camphene, p-cymene, δ-3-carene, α-humulene, δ-1-limonene, linalool, (E)-β-ocimene, α-pinene, and β-thujone), benzenoids of which benzaldehyde was the most abundant, aldehydes (decanal, heptanal, nonanal and octanal), and hydrocarbons (decane, heneicosane, heptadecane, hexadecane, nonadecane, nonane, octadecane, tetradecane, tridecane and undecane) along with a cross-section of other compounds. Subsequent identification and quantification of critical ordorants will facilitate selecting new cultivars with quantitative and qualitative improvements in fragrance.
The Effects of Conditioning Strawberry Plug Plants under Altered Red/Far-red Light Environments
Authors: Black Brent L. , Swartz Harry J. , Deitzer Gerald F. , Butler Bryan , Chandler Craig K.
Published: February 2019

The effect of altered red/far-red light environment on subsequent field performance of strawberry plug plants was tested. Two wavelength-selective plastic films were compared to neutral shade and full-sun control for conditioning `Chandler' strawberry plug plants before transplanting to a winter production system. The following year, plug plants of `Chandler', `Sweet Charlie', and `Allstar' were conditioned under the same treatments, with the addition of a continuous incandescent light and a short-day photoperiod, and plant performance was followed in the winter production system in Florida, a cold-climate annual hill system in Maryland, and in a low-input greenhouse production system. During the first year, the red light-filtering film slightly advanced fruiting in Florida. However, during the second year, the effect of the red light-filtering film was not significant, and a short-day treatment resulted in a greater reduction in runnering and increased early crown and flower development. For June-bearing strawberry plants maintained above 20 °C, altering the red/far-red environment did not consistently advance flowering.
Effects of Cluster Size and Shoot Type on Characteristics of Pecan Nuts
Authors: Rohla Charles T. , Smith Michael W. , Maness Niels O.
Published: February 2019

Whole fruit clusters of `Pawnee' pecan [Carya illinoinensis (Wang.) C. Koch.] were collected from three shoot types: terminal and lateral shoots without a secondary growth flush and shoots that had an early-season secondary growth flush. Fruit per cluster were counted and nuts were individually harvested, weighed, shelled and graded. Bloom the following year was determined for the same shoots where clusters were collected. Wafers (cotyledons that failed to develop) were not associated with cluster size or shoot type. When wafers were included in the data, nut weight, kernel percentage and return bloom were not affected by cluster size or shoot type. However, when wafers were excluded from the data there were significant relationships of cluster size and shoot type with the dependent variables. Cluster size on lateral shoots was negatively related to nut weight and kernel percentage. Cluster size on terminal shoots without a secondary growth flush was inversely related to kernel percentage, but not related to nut weight. When shoots had a secondary growth flush, cluster size was not related to kernel percentage or nut weight. There was a positive linear relationship between cluster size and total kernel weight for the three shoot types. Return bloom of terminal shoots without a secondary growth flush was negatively related to cluster size, but cluster size did not affect return bloom of the other shoot types. The number of shoots that developed the following year was positively related to cluster size for terminal and lateral shoots, but not for shoots with a secondary growth flush. Shoots with a secondary growth flush produced substantially more shoots with larger fruit clusters the next year than the other shoot types.
Peach and Nectarine Quality Following Treatment with High-temperature Forced Air Combined with Controlled Atmosphere
Authors: Obenland David , Neipp Paul , Mackey Bruce , Neven Lisa
Published: February 2019

Yellow- and white-fleshed peach [Prunus persica (L.) Batsch] and nectarine [Prunus persica (L.) Batsch var. nectarina (Ait) Maxim.] cultivars of mid- and late-season maturity classes were subjected to combined controlled atmosphere–temperature treatment system (CATTS) using heating rates of either 12 °C/hour (slow rate) or 24 °C/hour (fast rate) with a final chamber temperature of 46 °C, while maintaining a controlled atmosphere (CA) of 1 kPa oxygen and 15 kPa carbon dioxide. Fruit seed surface temperatures generally reached 45 °C within 160 minutes and 135 minutes for the slow and fast heating rate, respectively. The total duration of the slow heating rate treatment was 3 hours, while 2.5 h was required for the fast heating rate treatment. Following treatment the fruit were stored at 1 °C for either 1, 2, or 3 weeks followed by a ripening period of 2 to 4 d at 23 °C and subsequent evaluation of fruit quality. Fruit quality was similar for both heating rate treatments. Compared with the untreated controls, CATTS fruit displayed higher amounts of surface injury, although increased injury was only an important factor to marketability in cultivars that had high amounts of surface injury before treatment. The percentage of free juice in the flesh was slightly less in CATTS fruit early in storage but was often greater in treated fruit toward the end of the storage period. Slower rates of softening during fruit ripening were apparent in CATTS fruit. Soluble solids, acidity, weight loss and color all were either not affected or changed to a very small degree as a result of CATTS. Members of a trained sensory panel preferred the taste of untreated fruit over fruit that had been CATTS but the ratings of treated and nontreated fruit were generally similar and it is unclear whether an average consumer could detect the difference. Although further work needs to be done regarding the influence of CATTS on taste, it otherwise appears that CATTS does not adversely affect the marketability of good quality fruit and therefore shows promise as a nonchemical quarantine treatment for peaches and nectarines.
Vase Life of Imported Anthurium Flowers Evaluated in Japan in Relation to the Effects of Postimportation Benzyladenine Treatment
Authors: Fukui Ryo , Kikuchi Saori , Ichida Yuko , Honjo Hitoshi
Published: February 2019

Effects of postimportation treatment of benzyladenine (BA) on vase life of imported anthurium flowers was examined after receiving the flowers in Japan and placing them either individually or together in vase solution. Cut anthuriums of two cultivars imported from Hawaii via air-freight were sprayed with 200 μg·m L–1 of BA upon arrival, and vase life of the flowers were evaluated by numerating days before observing apparent discoloration at the distal end of spadix. BA treatment significantly extended the vase life (by up to 22 d) in two cultivars in most cases during summer, but the effect was inconsistent in each cultivar when the test was done in winter. The effect of BA verified in summer was either nullified or significantly diminished by placing 10 flowers together in vase solution. In these tests, bacteria were isolated more frequently from the scape segments of bunched flowers than those of individual flowers. However, vase life was not affected when the vase solutions were inoculated with Xanthomonas axonopodis pv. dieffenbachiae. These results indicate that the postimportation BA treatment is mostly effective in extending the vase life of cut anthuriums during summer, but may not be reliable during winter in temperate regions. The preliminary evidence suggests that bacterial growth in vase solution be related to the loss of the effect of BA, but the pathogen of bacterial blight growing in the vase solution or invading the xylem of the scape is not responsible for the reduced longevity of imported anthuriums.
Application on Rooting of Hazelnut Layers
Authors: Erdogan Veli , Smith David C.
Published: February 2019

`Barcelona' hazelnut (C. avellana L.) shoots were girdled and stool layered in a factorial design with three tissue removal (leaf, bud and meristem removal) and two hormone (with or without 750 ppm IBA) treatments. Percent rooting, rooting grade (0 to 5), shoot length, shoot diameter, and total number of buds were determined. Average percent rooting was >90% for all treatments. Girdling alone gave as high percent rooting as hormone application. The main effect of IBA was on root quality rather than percent rooting. About 75% of the hormone-treated rooted layers could be directly planted (grades 3 to 5), compared to 44% for the control, but shoot length, shoot diameter and total number of buds decreased with IBA application. Bud removal did not affect average percent rooting while meristem removal reduced it slightly. The percentage of layers having grades 3 to 5 was lower for the meristem and bud removal treatments than for leaf removal. Our results support the adoption of stool layerage with girdling and IBA application for the production of strong, well-rooted trees suitable for planting directly in the orchard.
Vegetative Propagation of Mature Eastern and Carolina Hemlocks by Rooted Softwood Cuttings
Authors: Jetton Robert M. , Frampton John , Hain Fred P.
Published: February 2019

This study tested the effects of cutting length and auxin (NAA) concentration on adventitious root formation in softwood stem cuttings from mature eastern hemlock, Tsuga canadensis (L.) Carr., and carolina hemlock, T. caroliniana Engelm. Overall rooting percentage (41%) and percent mortality (22%) were higher for eastern hemlock compared with carolina hemlock (10% rooting and 13% mortality). Rooting percentage of each species responded differently to varying auxin concentrations (0, 1, 2, 4, 8 mm NAA). Maximum rooting (56%) for eastern hemlock occurred at 0 mm NAA; then decreased with increasing auxin concentration. Carolina hemlock rooting percentage increased from the control to a maximum (16%) at 1 mm NAA; then decreased with increasing auxin concentration. For both species, the lowest mortality occurred at the same auxin concentration as maximum rooting. The highest rates of mortality coincided with the same concentrations as the lowest rooting percentages. At all auxin concentrations, eastern hemlock had a higher number of roots and greater total root length relative to carolina hemlock. Mortality among 6-cm stem cuttings was twice that observed for 3-cm cuttings of both species. However, 6-cm cuttings of eastern hemlock that did form adventitious roots had more roots and longer total root length compared with 3-cm cuttings. Chemical name used: 1-naphthalenacetic acid.
In Vitro Regeneration and Mass Propagation of Ruta graveolens L.—A Multipurpose Shrub
Authors: Faisal Mohd , Ahmad Naseem , Anis Mohammad
Published: February 2019

A protocol for rapid in vitro propagation of Ruta graveolens L. through high-frequency shoot induction from nodal explants was established. Proliferation of shoots from nodal segments was achieved on Murashige and Skoog medium supplemented with various concentrations of BA, Kin, IAA, and NAA, either singly or in various combinations. The highest shoot regeneration frequency (98.5%) and the highest number of shoots per explant (40.2 ± 2.8) was obtained on MS medium supplemented with 10 μm BA and 2.5 μm NAA. In vitro regenerated shoots rooted best on half-strength MS medium containing 0.5 μm IBA. Rooted shoots, following acclimatization in the greenhouse, were successfully transferred to field conditions, and 90% of plants survived. The efficient in vitro regeneration of the whole plant can be used as a fast and reliable method to transform R. graveolens genetically for its active principles.
Comparison of Commercial Boron Spray Products Applied at the Pink Flowering Stage on 'Fuji' Apple
Authors: Peryea Frank J.
Published: February 2019

Two multiyear field studies were conducted to compare the phytoavailability and effectiveness of a variety of commercial foliar B fertilizer sprays applied at the pink flowering stage to 'Fuji'/EMLA.26 apple trees grown under irrigated semi-arid conditions. Treatments included products that differed by initial chemical form of B, physical state, and presence of additives of varying composition. Additional treatments were polymeric urea added to one B product and soil application of one B product. Boron application rates varied from 0.56 to 1.68 kg·ha–1·yr–1. All of the B sprays increased flower cluster B concentration in all years. The B sprays at the lower rate sometimes but not always increased leaf B concentration. Increasing the B rate substantially increased plant tissue B concentrations. In general, there was little substantive difference between the tested products/product mixtures on plant tissue B concentrations. Flower cluster B in the ground-applied B treatment was similar to the water control; however, leaf B concentration corresponded to the B spray treatments, indicating effective uptake of B from the soil during the early summer. Sodium polyborate-based products increased flower cluster Na concentration but not leaf Na concentration. The amount of Na contributed by Na polyborate-based products applied at commercial rates apparently was too small to be of horticultural concern. Fruit quality was excellent and was not affected by the experimental treatments in any year. Flower cluster and leaf B concentrations returned to near or at control levels in the season following the last spray application, validating the recommendation for annual B fertilizer applications to maintain adequate tree B status.
Growth and Water Relations of Littleleaf Linden Trees Established in Irrigated Buffalograss and Kentucky Bluegrass
Authors: Stewart J. Ryan , Kjelgren Roger , Johnson Paul G. , Kuhns Michael R.
Published: February 2019

Although transplanted trees typically establish and grow without incident in frequently irrigated turfgrass, their performance in precisely irrigated turfgrass in an arid climate is not known. We investigated the effect of precision irrigation scheduling on growth and water relations of balled-and-burlapped littleleaf linden (Tilia cordata Mill. `Greenspire') planted in buffalograss (Buchloë dactyloides [Nutt.] Engelm. `Tatanka') and kentucky bluegrass (Poa pratensis L.). Over 2 years, trees in turfgrass were irrigated either by frequent replacement based on local reference evapotranspiration, or precision irrigated by estimating depletion of soil water to the point of incipient water stress for each turfgrass species. Predawn leaf water potential and stomatal conductance of trees were measured during first-year establishment, and predawn leaf water potential was measured during a mid-season water-deficit period during the second year. Trunk diameter growth and total tree leaf area were measured at the end of each year. Values of predawn leaf water potential and stomatal conductance of trees in precision-irrigated buffalograss were lower (–0.65 MPa, 25.3 mmol·m–2·s–1) than those of trees in the other treatments near the end of the first growing season. The longer interval between precision irrigations resulted in mild water stress, but was not manifested in growth differences among trees across treatments during the first season. During the water-deficit period of the second year, there was no evidence of stress among the trees regardless of treatment. At the end of the second season, total leaf area of trees grown in precision-irrigated kentucky bluegrass (1.10 ± 0.34 m2) was 46% of that of trees grown in buffalograss (2.39 ± 0.82 m2) that were irrigated frequently. Trunk diameter growth of trees in frequently irrigated kentucky bluegrass (1.91 ± 2.65 mm) was 29% of that of the trees grown in buffalograss (6.68 ± 1.68 mm), regardless of irrigation treatment, suggesting a competition effect from kentucky bluegrass. We conclude that frequent irrigation of balled-and-burlapped trees in turfgrass, particularly buffalograss, is more conducive to tree health during establishment than is maximizing the interval between turfgrass irrigation. Regardless of irrigation schedule, kentucky bluegrass appears to impact tree growth severely during establishment in an arid climate.
New Name 'Styer Group' Proposed for Interspecific Hybrids of Exacum Species Native to Sri Lanka
Authors: Riseman Andrew , Sumanasinghe V.A. , Justice Douglas , Craig Richard
Published: February 2019

We propose the name Exacum Styer Group for an interspecific population derived from several Sri Lankan Exacum taxa. Confirmation of hybrid status was determined by the appearance of either unique trait combinations or intermediate forms of traits originally represented by individual native taxa. Through 12 sexual generations, the proposed cultivar-group continues to exhibit these unique traits and now forms a cohesive fertile population.
The Genes of Pumpkin and Squash
Authors: Paris Harry S. , Brown Rebecca Nelson
Published: February 2019

Pumpkin and squash (Cucurbita L. spp.) are important cucurbit crops and are grown in almost all arable regions of the world. The three economically important species, Cucurbita pepo L., Cucurbita moschata Duchesne, and Cucurbita maxima Duchesne are highly polymorphic in fruit characteristics, inspiring much research into their inheritance. A comprehensive list of genes for Cucurbita was last published more than a decade ago. This new gene list for pumpkin and squash includes descriptions of gene interactions and the genetic background of the parents that had been used for crossing to allow easy confirmation of previous work and provide a sound foundation for further investigation. This gene list includes 79 loci for phenotypic/morphological traits and 48 polymorphic allozyme loci. Linkage and mapping are discussed.
Photosynthetic Irradiance and Nutrition Effects on Growth of English Ivy in Subirrigation Systems
Authors: Pennisi Svoboda V. , van Iersel Marc W. , Burnett Stephanie E.
Published: February 2019

The growth of three english ivy cultivars in ebb-and-flow subirrigation systems was examined under three photosynthetic photon flux (PPF) treatments (low, medium, or high, corresponding to an average daily PPF of 3.2, 5.4, or 8.5 mol·m–2·d–1, respectively) and four fertilizer concentrations (0, 100, 200, or 300 mg·L–1 N) geared toward production of acclimatized foliage plants. Marketable quality english ivy can be subirrigated with 100 mg·L–1 N. Although 8.5 mol.m–2.d–1 produced the maximum shoot dry weight (SDW), good quality plants also were produced under 5.4 mol·m–2·d–1. `Gold Child', `Gold Dust', and `Gold Heart' english ivy produced with low fertility and low light may be better acclimatized and show superior performance in interior environments. Under light levels lower than 8.5 mol·m–2·d–1, `Gold Heart' had less variegation (12% or 21% for ivy grown under 3.2 or 5.4 mol·m–2·d–1, respectively). `Gold Dust' and `Gold Child' had 65% and 22% variegated leaf area, respectively, when grown under 5.4 mol·m–2·d–1 PPF. Under 5.4 mol·m–2·d–1 PPF, `Gold Dust' retains attractive foliage with overall perception of increased lighter-green coloration.
PEG-8000 Alters Morphology and Nutrient Concentration of Hydroponic Impatiens
Authors: Burnett Stephanie , van Iersel Marc , Thomas Paul
Published: February 2019

Osmotic compounds, such as polyethylene glycol 8000 (PEG-8000), reduce plant elongation by imposing controlled drought. However, the effects of PEG-8000 on nutrient uptake are unknown. Impatiens `Dazzler Pink' (Impatiens walleriana Hook. F.) were grown hydroponically in modified Hoagland solutions containing 0, 10, 17.5, 25, 32.5, 40, 47.5, 55, or 62.5 g·L–1 PEG-8000. Impatiens were up to 68% shorter than control plants when grown with PEG-8000 in the nutrient solution. Plants treated with PEG-8000 rates above 25 g·L–1 were either damaged or similar in size to seedlings treated with 25 g·L–1 of PEG-8000. Impatiens leaf water potentials (Ψw) were positively correlated with plant height. PEG-8000 reduced the electrical conductivity of Hoagland solutions as much as 40% compared to nontreated Hoagland solutions, suggesting that PEG-8000 may bind some of the nutrient ions in solution. Foliar tissue of PEG-treated impatiens contained significantly less nitrogen, calcium, zinc, and copper, but significantly more phosphorus and nickel than tissue from nontreated impatiens. However, no nutrient deficiency symptoms were induced.
Suppression of Phytophthora Root Rot in Red Raspberries with Cultural Practices and Soil Amendments
Authors: Maloney Kevin , Pritts Marvin , Wilcox Wayne , Kelly Mary Jo
Published: February 2019

Various soil amendments and cultural practices were examined in both a phytophthora-infested (Phytophthora fragariae var. rubi) (+PFR) and uninfested field (–PFR) planted to `Heritage' red raspberries. Although plants in the +PFR field did not exhibit typical disease symptoms due to unseasonably dry weather, their growth was less than those in the –PFR field. After 2 years, plants in the +PFR site had the highest yields in plots treated with phosphorous acid or amended with gypsum, whereas compost-amended plots had the lowest yields in both +PFR and –PFR sites. A second field study confirmed the positive effect of gypsum on growth and yield of raspberries in an infested site. In a third study, `Titan' raspberries grown under greenhouse conditions in pots containing unamended soil from the infested site, then flooded, exhibited severe disease symptoms; however, pasteurization of the soil, treatment with phosphorous acid and metalaxyl fungicide, or gypsum amendment mostly prevented symptoms from developing. These three studies suggest that a preplant soil amendment containing certain readily available forms of calcium, such as found in gypsum, can help suppress phytophthora root rot and increase survival, growth and yield of raspberries in sites where the pathogen is present.
Effects of Growing Media Containing Diatomaceous Earth on the Fungus Gnat Bradysia sp. nr. coprophila (Lintner) (Diptera: Sciaridae)
Authors: Cloyd Raymond A. , Dickinson Amy
Published: February 2019

Fungus gnats (Bradysia spp.) are major insect pests in greenhouses. The adult stage is primarily a nuisance whereas the larval stage is directly responsible for plant injury by feeding on plant roots or tunneling into stems. Insecticides are used to deal with fungus gnat larvae in growing medium, although sometimes with limited success. This study evaluated the potential of using a soil amendment—diatomaceous earth (DE) incorporated into growing media—for controlling the fungus gnat Bradysia sp. nr. coprophila. Two experiments were conducted by testing a series of growing media containing various concentrations of diatomaceous earth, and several without diatomaceous earth. The effects of the growing media containing diatomaceous earth on both the 2nd and 3rd instars of fungus gnat larvae were determined by recording the number of adults captured on yellow sticky cards (2.5 × 2.5 cm). Based on the results obtained from both experiments, the addition of DE to growing medium, at the concentrations tested, did not negatively affect or increase efficacy against both the 2nd and 3rd instars. This suggests that incorporating DE into commercially available growing medium may not be beneficial to greenhouse producers. However, further research is needed to assess whether differential larval susceptibility and moisture content influence the ability of DE to control soil-dwelling arthropods.
Regeneration of Habanero Pepper (Capsicum chinense Jacq.) Via Organogenesis
Authors: Santana-Buzzy Nancy , Canto-Flick Adriana , Barahona-Pérez Felipe , Montalvo-Peniche María del Carmen , Zapata-Castillo Patricia Yolanda , Solís-Ruiz Anabel , Zaldívar-Collí Amílcar , Gutiérrez-Alonso Omar , Miranda-Ham María de Lourdes
Published: February 2019

To induce multiple shoots from habanero pepper (Capsicum chinense Jacq.), nodes and stem segments were cultivated in MS medium supplemented with varying concentrations of kinetin, benzyladenine, and thidiazuron. The effect of the age of the explant in the medium on shoot formation and their latter development into plants was assessed. Ethylene concentration was measured along the experiments. Thidiazuron was the key growth regulator in the process, which at 3.4 μm induced seven to eight shoots that developed into healthy plants per explant. Plantlets in nonventilated vessels, where ethylene concentration was 0.25 ± 0.1102 μL·L–1, showed early defoliation and the formation of calli on the leaves and stems.
Influence of Seed Size, Testa Color, Scarification Method, and Immersion in Cool or Hot Water on Germination of Baptisia australis (L.) R. Br. Seeds
Authors: Boyle Thomas H. , Hladun Kristen
Published: February 2019

A series of experiments was performed to examine the germination responses of Baptisia australis (L.) R. Br. seeds. Germination tests were conducted at 23 °C and numbers of germinated seed were counted daily for 21 days. Seeds were separated into two size fractions using standard sieves. Seeds in the large-seeded fraction were heavier than those in the small-seeded fraction, but seed size/weight did not affect the germination percentage at 21 days (G21), the number of days to 50% of final germination (T50), or the number of days between 10% and 90% germination (T90 – T10). Seeds were classified into two groups based on testa color. Light-brown seeds (17% of total) were heavier and had lower G21 and higher T50 and T90 – T10 values than medium- to dark-brown seeds (83% of total). Seeds scarified mechanically germinated nearly 100% and had lower T50 and T90 – T10 values than untreated seeds. Untreated seeds had a higher T50 value than seeds soaked overnight in 20°C water, but the G21 and T90-T10 values were similar for the two treatments. Mechanical scarification followed by overnight soaking in 20 °C water yielded a G21 value of only 12%, and the low germination percentage was attributed to imbibition damage. When seeds were scarified in concentrated H2SO4 for 0, 1, 5, 20, 40, or 80 min, G21 values increased quadratically while T50 and T90 – T10 values decreased quadratically as the immersion time increased. To test the effects of moist heat on germination responses, seeds were immersed for 0, 0.5, 1, 2, 4, or 8 minutes in 85 °C water. G21 values increased linearly as the immersion period increased from 0 to 2 min but remained similar when the immersion time exceeded 2 min. The duration of immersion in hot water did not affect the T50 values whereas T90 – T10 values decreased linearly as the immersion period increased. We conclude that physical dormancy is responsible for temporal variation in germination of B. australis seeds. Scarifying seed in concentrated H2SO4 for 20 to 80 minutes may be the most practical means of treating bulk lots of B. australis seeds to obtain rapid and uniform (≥85%) germination.
Processing Tomato Yield and Fruit Quality Improved with Potassium Fertigation
Authors: Hartz T.K. , Johnstone P.R. , Francis D.M. , Miyao E.M.
Published: February 2019

The effect of K fertigation through subsurface irrigation lines on processing tomato (Lycopersicon esculentum Mill.) fruit yield and quality was evaluated in four field trials in California from 2002–04. Fields had exchangeable soil K between 0.48 to 0.85 cmol·kg–1, with high exchangeable Mg (10.6 to 13.7 cmol·kg–1) and a history of yellow shoulder (YS, a fruit color disorder) occurrence. K treatments evaluated included seasonal amount applied (0 to 800 kg·ha–1), fertigation method (continuous versus weekly), and timing (early, mid or late season); foliar K treatments were also included in the 2002 trial. In two fields total and marketable fruit yield were significantly increased by K fertigation, and fruit color improvements were observed in all trials. Among color parameters improved by K fertigation were YS incidence, blended color, and L*, chroma, and hue of the shoulder region of fruit. K fertigation did not affect fruit soluble solids concentration. Yield increased only with fertigation treatments initiated during early fruit set. The effects of fertigation method and rate were inconsistent. Foliar K application was ineffective in increasing either fruit yield or quality.
Yield and Leaf Quality of Processing Spinach under Deficit Irrigation
Authors: Leskovar Daniel I. , Piccinni Giovanni
Published: February 2019

Restrictions placed on water usage for farmers have prompted the development of irrigation management projects aiming at water savings of economically important crops. The objective of this work was to determine yield, water use efficiency, and leaf quality responses to deficit irrigation rates of processing spinach (Spinacea oleracea L.) cultivars. Three irrigation treatments were imposed with a center pivot system, 100%, 75%, and 50% crop evapotranspiration rates (ETc). Commercial cultivars used were `DMC 09', `ASR 157', and `ACX 3665'. Leaf quality was significantly affected by deficit irrigation rate and cultivar. Leaf yellowness was highest at 50% ETc, and was more evident for `ACX 3665'. The percent excess stem (>10 cm) was higher at 100% ETc. This response was greater in `ACX 3665' than in `ASR 157' and `DMC 09'. Marketable yields were significantly higher for `ASR 157' at either 100% or 75% ETc rates, compared to `DMC 09' and `ACX 3665'. High water use efficiency was also measured at 75% ETc for `ASR 157'. Minimum canopy temperature differences were detected among the irrigation treatments. This work demonstrated that it is possible to reach a 25% water savings in one season, without reducing yields when using vigorous cultivars.
Environmental Physiology of Growth and Flowering of Orchids
Authors: Lopez Roberto G. , Runkle Erik S.
Published: February 2019

Flowering potted orchids has become one of the largest segments of floriculture worldwide. Large-scale production of cuts or potted plants exists in China, Germany, Japan, The Netherlands, Taiwan, Thailand, and the United States. Despite the value of orchids, the flowering physiology of most orchid genera is not well described. Therefore, scheduling flowering crops for specific market dates (such as Easter or Mother's Day) is not possible for most genera. This paper summarizes world orchid production and reviews how environmental factors regulate growth and flowering of several commercially important orchid genera: Cattleya, Cymbidium, Dendrobium, Miltoniopsis, Phalaenopsis, and Zygopetalum. These genera primarily flower in response to relatively low temperatures, and, for some species and hybrids, flowering is promoted when the plants are also exposed to short photoperiods. Effects of light and temperature on growth and development are summarized for these genera, and implications for controlled production are discussed.
Transport of Cross-pollen by Bumblebees in a Rabbiteye Blueberry Planting
Authors: Brevis Patricio A. , NeSmith D. Scott
Published: February 2019

Rabbiteye blueberry (Vaccinium ashei Reade) is a bee-pollinated small fruit crop that often exhibits poor fruit set. Mixed cultivar plantings are recommended because cross-pollination is required for optimum yields, and bees are expected to transfer pollen from one cultivar to another. The objective of this study was to assess transport of cross-pollen by bumblebees in a rabbiteye blueberry planting. Experiments were conducted in 2003 and 2004 in a plot composed of `Brightwell' and `Climax' plants arranged in alternating rows. The proportion of `Brightwell' and `Climax' pollen carried on the bodies of bumblebees was estimated based on frequency distributions of pollen diameter, measured with a particle counter. About 75% of bumblebees collected in 2003 carried <20% cross-pollen. Proportions of cross-pollen in 2004 were higher than in 2003, but still, about 85% of bumblebees collected carried <40% cross-pollen. The proportion of cross-pollen carried by bumblebees changed during the flowering season. The greatest likelihood for cross-pollination occurred during the time of maximum bloom overlap, although the median proportion of cross-pollen was not >30% on any sampling day of 2004. The results from this study emphasize the need to select more self-fertile rabbiteye blueberry cultivars and to maximize bloom overlap in blueberry plantings.