bluuebunny/crossref_metadata_2025 huggingface dataset:
HEATED IRRIGATION FOR FROST PROTECTION
Authors: Martsolf J. David
Published: February 2019

An undertree sprinkler [Maxijet] irrigation system designed to deliver 42 to 80 l/hr to each of 570 citrus trees (planted 6.1 × 6.1 m, heights of the larger uniform trees: 2m) was fed through an irrigation water heater [Aquaheet]. The heater added up to a megawatt of heat to the irrigation pipeline by the combustion of diesel fuel. A porous orchard cover (59m × 64m × 3.6m; 0.38ha) sheltered one of six plots of similar size in a citrus orchard on the University of Florida campus in Gainesville. Two border zones, one 3 rows deep on the north border and one on the west tapering from 2 rows on the north to a single row on the south end reduce the edge effect for a total orchard area of 2.12 ha. A minicomputer based data acquisition system provided observations of temperature, wind speed and direction made as frequently as one scan per minute. The effect of the orchard cover, the undertree irrigation, the heated irrigation and combinations of these three methods on the orchard microclimate will be shown in graphs and diagrams of observations taken during the freezes of February 24-26, and December 24-25, 1989. A diagram of the potential effect of water temperature on latent heat transport in the orchard will be discussed as will be problems with documentation of dew point temperature with chilled mirrors under freezing conditions.
LEAF BLACKENING IN PROTEA NERIIFOLIA R. BR.
Authors: McConchie Robyn , Robbins N. Suzanne
Published: February 2019

Leaf blackening of Protea neriifolia is a common postharvest problem which renders flowers unsalable. Previous reports suggest that depletion of carbohydrates in source leaves caused by transfer of carbohydrates to the strong flower sink may be a major cause. Flowering stems of P. neriifolia were harvested in California under standard conditions and shipped to Baton Rouge, La. Upon arrival, the stems were re-cut (1 cm.), the number of leaves counted and the diameter and height of the flowers measured. Stems were transferred to 1 liter deionized distilled water containing 50 ppm hypochlorite, and 0.5% sucrose or no sucrose, and placed in a growth chamber (25°C) either with 12 hrs light (120 μmol/m2/s), or 24 hrs darkness. Number of leaves 10% black, flower diameter and height, and carbon exchange rates were measured every two days over a 16 day interval. Soluble and insoluble nonstructural carbohydrates were determined and assimilate export rate was estimated for each sampling day. Stems placed in the light maintained healthy foliage while those in the dark had 77-l00% of their leaves 10% black by day 8. Flower and leaf quality in the fight treatment were superior with addition of sucrose to the vase solution. Influence of treatments on carbohydrate metabolism in relation to leaf blackening and flower development will be discussed.
UNICONIZOLE AFFECTS GROWTH AND WATER RELATIONS OF LIGUSTRUM
Authors: Zajicek Jayne M. , Steinberg Susan L. , McFarland Marshall J.
Published: February 2019

Growth of ligustrum (Ligustrum japonicum `Texanum') was controlled by the application of the growth regulator, uniconizole, at 3 mg A.I. per 7.6 liter pot. Seventy-nine days after application, growth regulated plants had shorter internodes, smaller stem diameters and reduced secondary branching and new leaf production. Differences in daily water use between the two treatments began to appear at the same time that differences in growth became apparent. Total water use of treated plants was 13% less than the control. When daily water use was normalized on a leaf area basis, water use between treatments was similar, suggesting differences in total water use were primarily due to differences in leaf area. Under well-watered conditions, the sap flow rate in the main trunk of plants in both treatments ranged between 60 and 100 g h-1 m-2 of stem area. Leaf conductance, transpiration rate and water potential were also similar for treated and control plants.
RELATIVE COLD TOLERANCE OF FOUR UNBUDDED PISTACHIO SEEDLING ROOTSTOCKS
Authors: Ferguson Louise , Buchner R.
Published: February 2019

Currently, the California pistachio industry relies upon 4 rootstock; Pistacia integerrima, P. atlantica and 2 different hybrids of P. atlantica × P. integerrima. Although observations have been made, no trials have established the relative cold tolerances of these rootstock. The above four rootstock were planted in June, 1989, in Shasta County, California. Each rootstock was repeated once within the 100 replications of the randomized complete block experimental design. The trees were unbudded. The lowest winter temperature of 14°F (-24°C) occurred in February, 1990. When the trees were rated for damage in April, 1990, P. atlantica displayed only 3% mild tip burn damage compared to 56% tip burn for P. atlantica × P. integerrima (commercially known as UCB #1), 79% tip burn for P. atlantica × P. integerrima (commercially known as Pioneer Gold I) and 95% severe dieback for P. integerrima. Five superior P. integerrima rootstooks, with no damage, were identified.
A NEW METHOD FOR MEASURING TOTAL POROSITY IN HORTICULTURAL SUBSTRATES
Authors: Fonteno William C.
Published: February 2019

The determination of air and water holding capacities of horticultural substrates has been plagued by errors in measurement. The amount of air and water held at container capacity is influenced by the substrate and container height. Container capacity can be established through specific measurement. Air space, the difference between total porosity and container capacity, is usually poorly determined because of errors in total porosity measurement. Most researchers calculate total porosity (St) from the formula: St = 1-(ρb/ρp), where ρb is the dry bulk density and ρp is the particle density. While bulk density is usually measured, particle density is not. Many times an average ρp of 2.65 Mg·m-3 for mineral soils is used. This sometimes creates large errors in calculating total porosity because the values of ρp for horticultural substrates range from 0.35 to 2.1 Mg·m-3. Total porosity can be measured with great accuracy at 0 kPa tension on a pressure plate apparatus, but is costly in equipment and time. Using a modified method of extraction and a new apparatus, using standard aluminum soil sampling cylinders, total porosity was measured with an 85% reduction in time end no decrease in accuracy.
ASEXUAL PROPAGATION OF CEANOTHUS VELUTINUS AND CEANOTHUS FENDLERI
Authors: Krishnan Sarada , Pirastah Bahman , Hughes Harrison
Published: February 2019

The evergreen Ceanothus velutinus and semi-evergreen C. fendleri are native Colorado, drought-tolerant shrubs. They are of interest for landscaping and rock gardens, but have poor seed germination as well as vary considerably in growth form and habit. Asexual propagation methods would be important for commercial development of these species. Basal hardwood cuttings of C. velutinus were rooted using four different concentrations of IBA. The highest concentration of IBA (0.8%) showed the highest rooting (14.8%), while the average number of roots per cutting was highest for 0.1%. Ceanothus fendleri shoot tips were cultured on MS medium with four BA (0.89, 4.4, 8.9 and 17.8 μM) and three 2ip concentrations (24.6, 49.0 and 73.6 μM). After nine weeks an average of six shoots were produced in treatments having 4.9 μM of BA. Lower concentrations of BA up to 9.8 μM were better than higher concentrations of BA or 2ip. There was a tendency for production of callus at the higher levels of 8A and all levels of 2ip.
SQUALENE APPLIED TO GRAPEFRUIT PREVENTS CHILLING INJURY
Authors: Nordby Harold E. , McDonald Roy E.
Published: February 2019

In previous studies squalene was shown to be synthesized in grapefruit under temperature-conditioning parameters optimal for preventing chilling injury (CI). In this study, squalene and its saturated derivative squalane were applied to the fruit as sprays or dips under various protocols. Fruit were stored for various times under conditions conducive to CI. The best results were obtained when fruit were sprayed with squalene dissolved in hexane. After 4 weeks at 5C, 5% squalene reduced CI 69% and 10% squalene reduced CI 80% whereas, temperature conditioning reduced CI by a comparable amount (67%).
MICROPROPAGATTON OF ACER GINNALA.
Authors: Ferreras Yrina P. , Swartz Harry Jan
Published: February 2019

Shoot proliferation of Acer ginnala Maxim. (Amur maple) from nodal-segments was obtained on Murashige and Skoog salts and vitamins supplemented with 25 nM thidiazuron and 3% sucrose. Higher concentrations of cytokinin resulted in callus formation at the base of explants. Explant orientation had a significant effect on shoot elongation. Explant elongation and proliferation were correlated. Plants inverted in the medium elongated and proliferated readily. Branching was obtained primarily from axillary buds several nodes basal to the apex. Gelling agent type did not affect proliferation. Vitrification was significantly affected by type of gelling agent, gelling agent concentration and thidiazuron concentration. In vitro shoots rooted readily even in medium containing adenine. Greater than 95% of the in vitro plants established in the greenhouse.
COMPARISON OF CHEMICAL AND MECHANICAL WEED CONTROL STRATEGIES FOR COWPEA
Authors: Kahn Brian A. , Schatzer Raymond Joe , Nelson Wendy A.
Published: February 2019

The herbicides trifluralin, metolachlor, and paraquat were compared for efficacy of weed control in cowpea with and without cultivation as a supplemental strategy for two years. Herbicides also were compared against a no-herbicide control (with and without cultivation). Cultivation had no significant effect on seed yield, biological yield, or harvest index of cowpea. Paraquat, used in a “stale seedbed” system, was ineffective for weed control and did not change cowpea yield from that of the no-herbicide control. Trifluralin and metolachlor more then tripled cowpea seed yield compared to that of the no-herbicide control in 1988, when potential weed pressure was 886 g m-2 (dry wt.). Trifluralin and metolachlor did not significantly increase cowpea seed yield compared to that of the no-herbicide control in 1989, when potential weed pressure was 319 g m-2 (dry wt.). However, in 1989, these two herbicides each still increased net farm income by $206 per hectare compared to the income obtained without an herbicide.
CRANBERRY BOG SOIL pH: HISTORIC AND CURRENT RELATIONSHIP TO YIELD.
Authors: DeMoranville Carolyn
Published: February 2019

An extensive study (276 samples) was conducted in 1960 to correlate cranberry (Vaccinium macrocarpon, Ait.) bog soil pH and productivity (Chandler, F. B. and Demoranville, I. E. 1961. Cranberries 26(3):9-10). At that time, soil pH averaged 4.37 and excellent productivity was represented by a yield greater than 10 mT/ha. Thirty years later, when more than 28 mT/ha is considered good yield, soil samples will be collected from these same sites and evaluated for pH by the methods used previously. Production records for the pact three years will be obtained and the average value for each location used to construct a regression of bog yield vs soil pH. Information presented will include: 1. productivity vs soil pH in 1960 and 1990; 2. change in soil pH after 30 years?; 3. possible reasons for changes-if any (grower interviews); 4. implications for the future.
FERTILIZER SOURCE INFLUENCES GROWTH OF `ANGELIKA RED' POINSETTIAS
Authors: Lehmann Jerry , Albrecht Mary Lewnes
Published: February 2019

During 1988, N-chlorosis was a problem with `Angelika Red' poinsettias in some parts of the Great Plains. A study was conducted with `Angelik a Red' poinsettias using one of 3 commercially available water-soluble fertilizers: 20N-9P-17K, 20-4-17, and 15-7-14. Plants were finished with either plain water or 15-9-21 (a commercially available poinsettia fertilizer). Data were taken when plants were marketable.

Fertilization with 20-9-17 resulted in reduced stem dry weight in comparison to the other 2 production fertilizers. Bract display was reduced when 20-9-17 was used for production and plain water for finishing. Total foliar-N was greatest for this treatment indicating an accumulation of NH4-N. Production with 20-4-17 and finishing with either plain water or 15-9-21, or production with 15-7-14 and finishing with 15-9-21 produced plants with the greatest dry weights and inflorescences.
WATER RETENTION IN SOILLESS POTTING MEDIA
Authors: Elliott George C.
Published: February 2019

Water retention was measured in soilless potting media irrigated by capillary mat, flood and drain, drip or overhead sprinkler. Media were amended with wetting agent or hydrophilic polymeric gel. Pots 12 cm high with a volume of 465 cm3 were loose-filled to the top with media. Potted media were wetted overhead with 120 ml water, then pots were randomly assigned to irrigation treatments. Capillary mat irrigation was continuous; other irrigation treatments were applied daily. Water retention was measured by weighing. Irrigation was continued until no further retention was measured. Water retention was significantly affected by irrigation method and medium amendments. Irrigation method followed the order overhead >= drip > flood and drain >= mat. Hydrophilic gel increased water retention, but in contrast to previous results, wetting agent did not, nor was any interaction of gel and wetting agent observed. Retention of water at container capacity, measured in situ at the end of each experiment, was significantly larger than actual retention.
ENVIRONMENTAL AND SEED TREATMENT EFFECTS ON GERMINATION AND GROWTH OF INDIAN PAINTBRUSH
Authors: Borden Pamela
Published: February 2019

Indian Paintbrush (genus Castilleja) is a group of attractive wildflowers in which some species are facultative parasites on native grasses during early growth. This study hopes to characterize optimum germination, cultural and host requirements of several species. Lots of 100 seed of wild-collected Castilleja coccinea (L.) Spreng. produced 22% germination without pre-treatment or presence of host plants 10 days after seeding at 21°C with 12 hours light. Seed soaked 24 hours in distilled water, 10 mg/l GA3 or-post-plant treated with Regal Crown nutrient and growth regulator soluotion did not significantly differ from above. Moist stratification at 4°C for 20 days significantly increased germination to 46%. Further stratification (up to 80 days) did not further increase germination. Additional data on light, temperature, media and presence of host plants will also be presented for this and other species.
TRAINING AND PRUNING HEDGEROW ALMONDS
Authors: Edstrom J. , Krueger W. , Connell J. , Micke W. , Osgood J. , Reil W. , Yeager J.
Published: February 2019

In 1979 a Nonpareil-Price almond orchard, was planted 2.2m × 6.7m (270 trees/acre). Four pruning treatments were imposed on the hedgerow planting at the end of the first year. 1. Interplanted: Trees trained to 3 scaffolds then standard pruned 2nd-6th years. Alternate trees were whisked back during 7th and 8th years and whisked trees removed after 9th year. 2. Permanent Hedge: Trees trained to 3 scaffolds and standard pruned throughout. 3. Two Scaffold Hedge: Heavy 2nd and 3rd year training required to form 2 main scaffolds growing into the row middles then standard pruned. 4. Unpruned Hedge: Trees trained to 3 scaffolds then no further pruning. Treatment with alternate trees whisked back had 15% reduced yield each year following whisking. Removing these heavily pruned alternate trees at the 9th year then reduced yields an additional 30%. Now, three years after removal, yield still lags by 18%. Accumulating six years yield data shows no differences between the three treatment maintained as hedgerows. However, whisking and removing alternate trees resulted in 2000 lbs less yield over the 6 year period.
EFFECT OF FOLIAR FERTILIZATION AND SOME GROWTH REGULATORS ON THE CHEMICAL COMPOSITION AND THE PHOTOSYNTHETIC PIGMENTS OF CROTON PLANT LEAVES
Authors: Shedeed Mahmoud R. , El-Gamassy Khairy M. , Almulla Alaa M.
Published: February 2019

The experiment was designed to investigate the effect of Fulifertil at levels 0,2 and 4 gm/L and growth regulators GA3 at 0,100,200 and 300 ppm also kinetin at 0,25,50 and 75 ppm and their combination on croton plants. In general the results indicate that there were increases in the carbohydrates, nitrogen, phosphorus and potassium content. The anthocyanins and carotenoids pigments were increased while chlorophyll `a” and “b” pigments were decreased. These findings are required to give colorful leaves which give good display.
EFFECT OF RACEME THINNING AND GIRDLING ON FRUIT SET OF MACADAMIA NUT
Authors: Ueunten Gary R. , Kobayashi Kent D.
Published: February 2019

Premature fruit drop of Macadamia integrifolia is a major limitation to yield. This study investigated the effects of raceme thinning and branch girding on find fruit set of macadamia nut 'Ikaika' and 'Keaau'. Eleven-year old grafted trees grown near Hilo, Hawaii were used. Racemes were thinned to 1, 2, or 4 racemes per branch two weeks after anthesis. The base of half these branches was girdled when the racemes were thinned.

Premature fruit drop occurred during the 97 and 151 days following anthesis for `Keaau' and `Ikaika', respectively. Peak fruit drop occurred within 70 days after anthesis for both cultivars. Raceme thinning and girdling had no effect on final fruit set (nuts/branch) of `Ikaika' 151 days after anthesis. There was a significant interaction between raceme thinning and girdling on final fruit set of `Keaau'. Branches with four racemes set more fruit than branches with one or two racemes. Raceme thinning and girdling had no effect on fruit retention (% of initial fruit set retained through final fruit set per branch) of `Ikaika'. There was a significant interaction between girdling and raceme thinning on fruit retention of `Keaau'. Branches with four racemes had greater fruit retention than branches with one or two racemes. Premature fruit drop may be altered on individual branches by altering raceme load and limiting phloem transport of assimilates into the girdled branch.
A SIMPLE METHOD TO CONTROL HUMIDITY IN SMALL EXPERIMENTAL CHAMBERS
Authors: Forney Charles F. , Brandl David G.
Published: February 2019

Humidity is an important component of the enviornment that influences the growth, development and storage life of most horticultural crops. A method to control relative humidity (RH) in experimental chambers using solutions of glycerol-water has been developed. A constant RH can be established and maintained by bubbling air through a glycerol-water solution of known water content. The air rapidly reaches equilibrium with the glycerol-water solution producing the desired RH. The relationship of the specific gravity (SG) of glycerol-water solutions and the corresponding equilibrium RH was determined. Any desired RH can be produced by using solutions of the appropriate SG ranging from 100% with pure water (SG 25/25 = 1.000) to 0% with pure glycerol (SG 25/25 = 1.261) This system can be used in flow through systems by bubbling the incoming air through the solution or in closed systems by circulating air through the solution and the chamber. Multiple jars of solution can be used for more precise RH control. The effects that temperature and atmospheric pressure in the jars have on the equilibrium RH will be discussed.
RESPONSE OF APPLE SHOOT CULTURES TO COLD TREATMENT
Authors: O`Connor P.A. , Korban S.S.
Published: February 2019

Established shoot cultures of three apple genotypes, `Dayton', `McIntosh', and `Golden Delicious' were subcultured into culture tubes containing a modified MS medium and maintained in a dark chamber at 1.0±0.5°C for periods of 3, 6, 9, and 12 months. Following each cold storage period, culture tubes of each of the three genotypes were transferred to a growth room and maintained under 16 h of light (60 uEs-1m-2) and 21°C. The overall morphological condition of each shoot was then recorded. After 4 weeks of growth, both number and length (in cm) of proliferating shoots were recorded. In general, shoots subjected to 3 or 6 months of cold storage remained green however most cultures did not initiate any new shoots. Cultures subjected to 9 or 12 months of cold treatment were etiolated however new axillary shoots were observed. The proliferation rate after 4 weeks of growth under standard growth conditions were variable among the different genotypes. The implications of using long term cold storage of apple shoot cultures will be discussed.
A STUDY OF FLOWER BUD DIFFERENTIATION IN SWEET CHERRY BY SCANNING ELECTRON MICROSCOPE
Authors: Kappel Frank , Bouthillier M. , Veto L.
Published: February 2019

Buds from 12-year-old `Bing' sweet cherry trees were collected biweekly from May 25, 1989 to August 31, 1989 and periodically therafter until the spring of 1990. Buds were partially dissected by removing outer bud scales, then fixed in a solution of 3% glutaraldehyde and 2% formaldehyde for 24 hrs. The buds were then stored in phosphate buffer solution at 6.8 pH at 4C for a maximum of 6 months. Buds examined with the SEM were critical point dried, mounted and coated with gold. Anthesis occurred April 28 and fruit were harvested July 6. Rapid changes in the development of the buds occurred during the period between July 7 and July 20. Flower primordia were just barely visible on July 7 in the most advanced buds but by July 20 multiple flowers were visible with sepal primordia apparent. By Aug 3 petals were clearly defined and stamen primordia evident. By August 17 anthers were clearly visible and pistil primordia were evident. Most buds produced 2 flowers with some producing a third. The third flower trailed the other two buds in development.
MUTATION, A MICROCOMPUTER MODULE DESIGNED FOR PLANT BREEDING AND GENETICS
Authors: Staub Jack E. , Braunschweig Karl
Published: February 2019

A teaching module was developed for computer-aided instruction of mutation theory. The Hypercard-driven, Macintosh compatible module illustrates the concepts of: 1) Changes in allele frequency with mutation pressure; 2) Number of alleles maintained in populations, and; 3) The Neutrality Hypothesis. The concepts are integrated in an application by using a game format.

Mutation is the ultimate source of genetic variation. Mutation pressure results in changes in allele frequency. Concept 1 illustrates the theoretical changes in allele frequency under pressure of reversible mutation. Mutation equilibrium is depicted as P=V/u+v; where v=mutation rates of allele A and u of allele a. The Infinite-Alleles Model of mutation is illustrated in Concept 2 and specifies characteristics of new mutations by F=1/4Nu+1, where F=fixation index and N=number in population. Concept 3 demonstrates the hypothesis that polymorphisms result from selectively neutral alleles maintained in a balance between mutation and random genetic drift.
MANAGEMENT AND ECONOMICS OF SEQUENTIALLY GROWN VEGETABLES
Authors: Coffey D. L. , Burnette R. R.
Published: February 2019

Cabbage, tomatoes and broccoli were grown sequentially at three levels of N fertilization with or without black polyethylene mulch in 1988 and 1989. Urea-NH4NO3 at 136, 270 or 404 kg·ha-1 was applied preplant or in triweekly increments via drip irrigation. Economic returns were estimated from wholesale prices and production expenses. Crops receiving the medium and high N levels produced higher yields than those receiving the low N level. Nitrate concentrations in the soil corresponded to the levels applied and declined over the season. Yields of the first crop of the sequence (cabbage) were higher from preplant than from irrigation applied N. Yields of the second crop (tomatoes) were not affected by method of N application. Mulched plots produced higher yields than nonmulched plots. Soil nitrate concentrations were higher from mulched than from nonmulched plots but the rates of decline over the seasons were no different between mulched and nonmulched plots. Estimated net returns among all treatments varied from 20 to 30 and -9 to 5 thousand dollars per hectare in 1988 and 1989, respectively. Tomatoes contributed greatest to the estimated returns. Weather conditions and wholesale prices fluctuated widely between years.
IMPROVEMENT OF PECAN BUD BREAK BY APPLICATION OF HYDROGEN CYNAMIDE.
Authors: Nuñez Humberto , Díaz Daniel H.
Published: February 2019

Pecan has an irregular bud break under mild climate areas, difficulting pollination and reducing yields, particularly in seasons when chilling accumulation is low and when only 50% of buds open. Hydrogen cyanamide (H2C N2) at 1, 2, 4% alone or with mineral oil (MO) at 2, 4% were evaluated for their effect on lateral bud opening of `Wichita' pecans, spraying branches on january 25 or february 8. H2C N2 and its mixtures with MO advances bud break 25 and 18 days as compared to control on first and second date application respectively; by march 20th shoots on applied branches had 8-14 cm lenght while control and MO treatments had only 2-3 cm.

Initial bud break was up to 85% on treated branches as compared to 60% of control; however and regularly, some shoots emerging from buds abscise thereafter. Remaining shoot number per branch was 4.8 with 4% H2C N2 or the mixture 2% H2C N2 + 2% MO on the first application date, and with 4% H2C N2 + 2% MO on the second date, as compared to 2.5 shoots of control. A 12% bud injury occurred with 4% H2C N2 on first date application and high rates of mo of second date.
SIMPLIFIED PESTICIDE RATE CONVERSIONS USING A PROGRAMMABLE CALCULATOR
Authors: Fitzpatrick G. E. , Verkade S. D.
Published: February 2019

Many pesticide labels contain rate recommendations in units that are not readily pertinent to container nursery production situations.

A program is presented, in the RPN programming language, for the conversion of pesticide rate terms from lb per ft2 to grams per container: f LBL A, RCL 2, ENTER, 1, 4, 4, X, STO 5, RCL 3, ENTER, 2, ENTER, g X2, f, X, STO 4, RCL 1, 4, 5, 3, ·, 9, X, STO 9, RCL 9, ENTER, RCL 9, ENTER, RCL 4, X, RCL 5,, g RTN.

Use of this program allows precise conversions of agricultural chemical application rates for container grown horticultural crops.
EFFECTS OF SHADE ON NET PHOTOSYNTHESIS, GROWTH AND YIELD OF STRAWBERRIES
Authors: Garrison S.E. , Williams J.M. , Barden J.A.
Published: February 2019

A greenhouse experiment was conducted to determine the effects of shade treatments (0, 30, 47 and 63%) on photosynthetic and growth responses of `Redchief' strawberries. Net photosynthesis (Pn) measured on plants under shade decreased as % shade increased. Pn of plants grown under shade but measured under saturating light intensities decreased after 30% shade. Light saturation curves of leaves allowed to expand in full sun and then placed under shade indicated a decrease in the saturation rate and point under 63% shade. Leaves which expanded under shade had decreased saturation rates and points at all levels. Specific leaf weight and total plant dry weight decreased linearly as % shade increased.

A field study in which plants were either shaded in the fall or in the fall and spring demonstrated a decreasing trend in berry number for plots which were shaded in the fall and spring. Berry number decreased in fall-shaded plants after 30% shade. In both cases, berry weight decreased with increasing shade.
TIMING OF CYTOKININ MEDIATED SHOOT INITIATION
Authors: Frett John J. , McCardell Richard
Published: February 2019

Several cytokinins at various concentrations were tested to determine which would stimulate the most synchronous shoot initiation. Kinetin was effective only at concentrations of 50 mg/L, while 2iP and zeatin where effective from 5 to 50 mg/L. BA at 10 mg/L produced the most synchronous and the greatest number of shoots. This treatment was used to determine at what point in development cytokinins stimulate shoots. Tissue was grown in the presence and absence of BA for various lengths of time. Application of BA for at least 10 days was required to initiate shoots. Explants were not effected by BA during the first 5 days of culture. Starving tissue for various periods caused a proportional lag in shoot production. Short pulses of BA at different developmental stages did not alter the cytokinin response. Vacuum infiltration of cytokinins prior to culture did not increase the BA response.
SHOOT GROWTH AND DEVELOPMENT OF `STARKSPUR SUPREME DELICIOUS' VARIES WITH ROOTSTOCK.
Authors: Rom Curt R.
Published: February 2019

Shoot growth `Starkspur Supreme Delirious' on 10 different rootstock was measured on 3-, 4- and 6-year-old trees at weekly intervals from budbreak until terminal bud formation. Spur density, spur development, and extension shoot leaf area development were measured in September. Growth rate was analyzed by regression against chronological time and accumulated growing degree days using linear and nonlinear statistics.

Rootstock affected shoot length, leaf number, leaf area, leaf size, leaf dry weight/leaf area and internode length. Trees on M.4, M.7 EMLA, P-1 and seedling had the longest shoots and highest shoot growth rate. Trees on P16 had least leaves and leaf area per shoot and smallest shoot leaves. Leaf dry wt./area were negatively correlated to leaf size. Typically, trees with shortest shoot length and smallest internode length had greatest spur density. Rootstock affected both rate and duration of shoot growth. Shoots on trees with P22 and P2 rootstocks grew for the shortest duration while trees on M.4 and M.7 EMLA grew for the longest period.
A CLASSROOM LABORATORY EXERCISE TO DEMONSTRATE SEED PRIMING
Authors: Duray Sharon A. , Davies Fred T.
Published: February 2019

Plant propagation instructors are challenged to develop laboratory exercises that demonstrate the theoretical aspects of seed germination. Seed priming or osmoconditioning is a relatively new technigue that has been shown to improve seed performance in horticultural crops. An esaily constructed seed priming system was designed using a pair of 2-liter glass jars, 2 aquarium pumps and air tubing. Eight sets of 40 seeds were each wrapped in coffee filters and laced in aerated treatment solutions consisting of 50 mmole K H2P O4 or an untreated control of distilled water. All seeds were treated or 0, 1, 3 or 5 days. Upon completion, seeds were rinsed, dried and placed into petri dishes containing moist filter paper to observe germination. A good test species for this exercise is Vinca rosea which typically has a poor germination percentage and rate. Seeds primed for 3 and 5 days significantly enhanced both germination percentage and rate in Vinca.
SCREENING OF SOMACLONAL VARIANTS IN VITRO TO PRODUCE INSECT RESISTANT PLANTS
Authors: Hadi Masood , Bridgen Mark P.
Published: February 2019

Callus cultures of Torenia fournieri `Compacta Blue' were initiated on a modified Murashige and Skoog salt medium (MS) with 2.26 uM 2,4-dichloro-phenoxy acetic acid. Shoots were regenerated from these cultures using the MS medium amended with 2.46 uM 3-indolebutyric acid and 8.88 uM 6-benzylaminopurine. These shoots were subjected to Tetranychus urticae Koch (twospotted spidermite) and Trialeurodes vaporariorum (Westwood) (greenhouse whitefly) in vitro. Pests were allowed to feed until such time that the pest population started to decrease due to lack of food. Remaining shoot tissue was placed on MS medium amended with 2.28 uM zeatin to -induce shoot formation. Shoots were acclimated to greenhouse conditions and evaluated for resistance to the pest to which they were subjected in vitro. Highly significant differences in pest numbers were found in somaclones when compared to control plants. A wide range of variability was observed within the somaclonal population.
EFFECT OF CONTAINER SIZE AND PRUNING ON GROWTH AND DEVELOPMENT OF DWARFING MANGO ROOTSTOCKS.
Authors: Cedeño-Maldonado A. , Méndez E.
Published: February 2019

Control of tree size is an important consideration in developing commercial mango orchards. The use of dwarfing rootstock is one of the methods available for controlling tree size. The development of techniques for increasing the effect of dwarfing rootstock is the objective of the present research. Container size treatments consisted of planting seedlings of different rootstock in containers of 1 to 8 L in size. Pruning treatments consisted of removing the shoot, root or shoot-root (combined) tips of young seedlings previous to planting. Most significant changes were produced by using the smallest containers and combined pruning. Most significant fresh and dry weight reductions were obtained in the smallest containers. Combined pruning produced a significant increase in fresh weight-of both roots and shoots but no significant changes in dry weight. Plant height was not significantly affected but bark thickness was significantly reduced by decreasing container size. Eldon a monoembryonic variety was significantly bigger than polyembryonic varieties.
ASPEN WOOD CHIP AND STONE MULCHES FOR ORNAMENTAL PLANTINGS IN INTERIOR, ALASKA
Authors: Holloway Patricia S.
Published: February 2019

Five woody ornamentals Rosa rugosa, Cotoneaster acutifolia, Malus baccata, Picea glauca and Pinus contorta var. latifolia, were grown for 4 seasons mulched with one of five treatments: 2.5 cm or 5 cm of crushed basaltic quarry stone, 5 cm or 10 cm of quaking aspen wood chips, and an unmulched control. Maximum soil temperatures at the 10 cm depth on the wood chip plots were decreased by as much as 8°C over control plots, and soil moisture was increased. Stone mulch plots showed a slight increase in both temperature and moisture. Soil minimum temperatures were lower on the wood chip plots than the other treatments early in the season, but were slightly higher in September. Soil pH and available N, P and K did not differ among mulch treatments. Weed growth was suppressed by all mulch treatments but was best controlled on the wood chip plots followed by the 5 cm stone plots. Plant growth for all species except Rosa rugosa was greatest on the stone mulch plots. Roses growing on the stone mulch plots and the control were subject to significant dieback from winter injury and did not show any difference in total growth after 4 years when compared with the wood chip plots. Plants grown on the wood chip plots exhibited varying degrees of nitrogen deficiency which may be related to reduced nutrient uptake in cooler soils or to a significant amount of rooting in the mulch-soil interface.
INFLUENCE OF LIGHT ON IN VITRO ROOT CHARACTER FOR WOODY PLANT MICROCUTTINGS.
Authors: Timmermann Renee , Smith M.A.L.
Published: February 2019

The structure and quality of the adventitious root system formed on a microcutting stem is crucial to the successful acclimation, survival, and ultimate performance of micropropagated plants. Despite increasing evidence that the rooting method impacts on the character of the framework root system, very little research has elucidated the consequences of standard rooting methods on plant quality and performance. Root initiation on microcuttings is handled by a wide range of strategies in commercial practice. In comparison to in vitro roots, ex vitro roots have smaller root diameters, larger vascular diameters, greater length, more branch root development, and root hairs. One important microenvironmental parameter - light - was investigated to determine its contribution to root character. Typically, in vitro root systems are exposed to light throughout the root initiation period. Parallel treatments were established of in vitro light and dark rooting and ex vitro rooting of four woody species. Regardless of light exposure, the overall diameter of adventitious roots was larger for in vitro treatments than the ex vitro treatment. Vascular development was significantly more advanced ex vitro. These results suggest that light is not a major influence contributing to the differences between ex vitro and in vitro root character.
PHOTOPERIOD EFFECTS ON REPRODUCTIVE DEVELOPMENT OF RABBITEYE BLUEBERRY
Authors: Darnell Rebecca L.
Published: February 2019

Containerized `Climax' and `Beckyblue' rabbiteye blueberry plants (Vaccinium ashei Reade) were exposed to 5 weeks of natural daylengths (i.e. gradually decreasing daylengths from 12 to 11 hr) or shortened daylengths (i.e. gradually decreasing daylengths from 10 to 8 hr) starting October 1. `Beckyblue' initiated twice as many flower buds under short days compared to longer days. The following spring, `Beckyblue' plants exposed to shortened photoperiods the previous fall had a greater percentage of floral budbreak (based on the number of flower buds formed within each treatment) and a shorter, more concentrated bloom period than did plants exposed to longer photoperiods the previous fall. Fresh weight per berry increased following the short fall photoperiod treatment, despite the fact that fruit number was higher. `Climax' did not respond to the photoperiod treatments in any way. Leaf carbon assimilation rates of both cultivars increased under short days, but there was no detectable effect of photoperiod on current carbon partitioning in either cultivar, suggesting that flower bud initiation is not limited by current source leaf assimilate supply under these conditions.
ASPARAGUS HARVEST DURATION, STORAGE CARBOHYDRATES AND YIELD
Authors: McGrady John , Tilt Phil
Published: February 2019

Asparagus (Asparagus officinalis) has great potential for production in the southwestern desert areas. Light, moderate and heavy harvest regimes were imposed on a one year old planting of `Mellowland Select' to determine the optimum duration of Spring harvest. There were no differences in mean spear weight or number of spears per plant in response to cutting pressure in 1987 or 1988. In 1989 both the light and heavy cutting regimes resulted in spears weighing 2.0 and 1. 5 grams less, respectively, than the moderate treatment and in fewer spears per plant. Consequently, 587 and 670 fewer kg/ha were produced in the lightly and heavily harvested plots in the third year. Total storage root carbohydrates were higher in the moderately harvested plots prior to harvest and again after fern production resumed in the third year. 1990 harvest data and implications for fall harvested or double-harvested asparagus will be discussed.
EFFECTS OF UNICONAZOLE MEDIA DRENCH AND FOLIAR SPRAY APPLICATIONS ON GROWTH OF PYRACANTHA, PHOTINIA, AND DWARF BURFORD HOLLY
Authors: Frymire Robert M. , Henderson Janet C.
Published: February 2019

Uniform liners of pyracantha (Pyracantha coccinea Roem `Lalandei'), photinia (Photinia × fraseri Dress) and dwarf Burford holly (Ilex cornuta Lindl. and Paxt. `Burfordii Nana') were potted into 3.8 liter containers in a pine bark:sand medium. Ten weeks later, plants received uniconazole treatments as a media drench or foliar spray. The uniconazole drench rates were 0, 0.5, 1.0, and 3.0 mg ai per container for all three plant species. The foliar application rates were 0, 50, 100 and 150 ppm for pyracantha, 0, 25, 50 and 100 ppm for photinia, and 0, 10, 25, and 50 ppm for dwarf Burford belly. Plant heights and widths were recorded at 3 week intervals, and leaf chlorophyll content was determined by calorimeter at the same time as height and weight measurements. At harvest, leaf counts, leaf areas, and shoot, leaf and root dry weights were determined. Initial results indicate that both foliar and media drench treatments of uniconazole reduced growth of pyracantha and photinia at all rates. Only the two highest rates decreased growth of dwarf Burford holly when applied as either a media drench or a foliar spray.
EFFECT OF GROWTH-REGULATING SUBSTANCES ON GROWTH OF HIBISCUS TREATED WITH UNICONAZOLE
Authors: Wang Yin-Tung
Published: February 2019

Hibiscus rosa-sinensis `Jane Cowl' were pruned several weeks after receiving 0.1 mg/pot uniconazole soil drenches to retard the growth. Plants then received foliar sprays of GA3 (50 ppm), KIBA (200 ppm), or PBA (200 ppm) immediately after pruning or when the lateral shoots had three leaves. Application of the above growth regulators immediately after pruning had no effect on plant growth. When treatments were delayed until the three-leaf stage, GA3 completely restored leaf production rate and partially restored shoot elongation and pedicel length. GA3 also increased leaf area, and the leaf specific weight was similar to leaves on plants not receiving uniconazole. GA3 increased flower production 175% and 65% more than plants treated with uniconazole and the untreated plants, respectively. KIBA and PBA had no effect on altering the growth of uniconazole-treated plants. Foliar application of a combination of GA3, KIBA and PBA at the three-leaf stage had an effect similar to that of GA3 alone. However, the effect of GA3 on growth appeared to be transient and repeated application may be required to maintain the restored growth of uniconazole-treated plants.
STOCKPLANT ETIOLATION, SHADING, AND STEM BANDING EFFECTS ON THE AUXIN DOSE-RESPONSE OF ROOTING IN SOFTWOOD STEM CUTTINGS OF CARPINUS BETULUS `FASTIGIATA'.
Authors: Maynard Brian K. , Bassuk Nina L.
Published: February 2019

Three experiments were undertaken to examine the effect of stockplant etiolation, shading, and stem banding, prior to cutting propagation, on the auxin dose-response of rooting in stem cuttings of Carpinus betulus `fastigiata'. A 2 × 2 factorial of etiolation and banding utilized stockplants forced in a greenhouse, etiolated for 1 week and banded with Velcro™ for 1 month. In a separate study shading was applied up the time of harvesting cuttings. IBA was applied to cuttings as an aqueous ethanol quick dip in concentrations ranging from 0 to 80 mM. Rooting percentage and number were best described, up to a peak response, by a linear function proportional to the logarithm of applied IBA. The inhibition of rooting by supra-optimal IBA was directly proportional to IBA concentration. Cuttings prepared from shoots which had been etiolated or banded rooted better at low IBA and at their respective optimal IBA levels. Cuttings from shoots receiving both etiolation and banding yielded higher rooting percentages and more roots per rooted cutting on average. Etiolation and banding served to increase both initial and maximum rooting capacities, and to reduce the sensitivity of cuttings to supraoptimal auxin-induced inhibition of adventitious root initiation. The auxin dose-response interacted with shading to yield the best rooting at 95% shade and 3.7 mM IBA.
JOHN H. PATTERSON'S USE OF HORTICULTURE FOR INDUSTRIAL WELFARE IN THE EARLY 1900'S
Authors: Hershey David R.
Published: February 2019

John H. Patterson, founder and president of the National Cash Register Co. (now NCR Corp.), is best known for his innovative business practices which made the cash register a standard product, Less well-known was his program of industrial welfare for NCR employees which included many uses of horticulture. Illustrations of the landscaping contests Patterson sponsored in his factory neighborhoods are shown in a collection of early 1900's glass lantern slides recently discovered in the University of Maryland Horticulture Building attic. The noted Olmsted landscaping firm was hired to design the NCR factory grounds. Neighborhood children were given company land, tools, instructions, and awards, enabling them to grow vegetables to sell and to give to their families. Patterson created these `Boys Gardens' to occupy youngsters who might otherwise break windows in the NCR factory and give the factory neighborhood a bad reputation. Although his program of industrial welfare was unique in an era of worker exploitation, Patterson justified the program because “It pays”.
EFFECT OF CA STORAGE ON THE ULTRASTRUCTURE OF CHLOROPLAST AND CHLOROPHYLL CONTENT OF CHINESE MUSTARD
Authors: Wang Hong , Herner Robert C.
Published: February 2019

A study of the ultrastructure of leaf tissues of Chinese mustard shows that there is a progressive degeneration of the membrane structure of the grana of the chloroplast accompanied with the appearance of globules of lipid material and loss of chlorophyll during leaf senescence. A controlled atmosphere of 5% CO2 plus 3% O2 maintained chloroplast grana membrane structure for up to 4 weeks storage at 10°C. Both 5% CO2 (in air) and 5% CO2 plus 3% O2 maintained the highest chlorophyll content compared to 3% O2 alone or in air (control).
CHILLING ENHANCEMENT OF ROOT REGENERATION IN APPLE CAN OCCUR WITHOUT BUDBREAK OR GROWTH OF ROOT SUCKERS
Authors: Arnold Michael A. , Young Eric
Published: February 2019

After receiving 0, 600, 1200, or 1800 hr. of chilling at 5C, one-year-old Malus domestica Borkh. seedlings were given 10 sec. root dips either 10,000 ppm K-IBA solution or water control. Following chilling and IBA treatments, 20 seedlings of each combination were placed in forcing conditions of 20 ± 2C root temperatures and either 20 or 5 ± 1C shoot temperatures. Five seedlings of each treatment were harvested after 0, 7, 14, and 21 days of forcing. Five C prohibited budbreak and bark slipage for up to 21 days. Under 20C, budbreak, shoot elongation and root growth all occurred earlier, faster, and reached a higher level with increased chilling. Twenty C root and 5C shoot temperatures during forcing resulted in large increases in the growth of adventitious shoots on lateral roots, but had little effect on the formation of adventitious shoots on the tap root. K-IBA prohibited development of adventitious shoots on roots, reduced shoot elongation more so than budbreak, and increased root regeneration across chilling hours. K-IBA inhibition of adventitious shoots did not alter the overall pattern of root regeneration enhancement by chilling.
FLORAL-DERIVED VOLATILE COMPOUNDS: A ROLE IN POLLINATION?
Authors: Archbold Douglas D. , Hamilton-Kemp Thomas R. , Loughrin John H.
Published: February 2019

Volatile compounds, commonly produced by flowers during bloom, have been described as insect attractants. Some of these compounds stimulate Pinus pollen germination in vitro (French et al., 1979, J. Agric. Fd. Chem., 27184-187), suggesting that such compounds may do the same in vivo. Red Delicious apple pollen was germinated on agar in a simple, enclosed in vitro bioassay system in the presence of a number of plant tissues, including apple, tomato, and chrysanthemum leaves, apple flowers, rose petals, and apple fruit slices. These tissues represent a diversity of types of volatile compounds, Pollen germination was recorded by microphotography after 1 and 2 hours, and percent germination was determined. Although stimulation of germination was not observed, macerated tomato leaves inhibited it. To determine if the volatile characteristics of cultivars differ, flowers of Red Delicious and Golden Delicious apple were harvested at full bloom. Their volatiles were collected, identified, and quantitated by capillary GC-MS. Among 8 major compounds common in the two cultivars, several quantitative differences were observed. These results will be discussed in relation to the potential role of volatiles in pollen germination.
ROOT DISTRIBUTION PATTERN OF NINE APPLE ROOTSTOCKS AT TWO NC-140 TRIAL LOCATIONS
Authors: Fernandez R. T. , Perry R. L. , Ferree D. C.
Published: February 2019

The 1980 NC-140 uniform apple rootstock trial plantings located in Michigan and Ohio were used to determine root distribution patterns of the nine rootstooks involved in the trial. The scion for the trial was Starkspur Supreme (Malus domestica Borkh.) on Ottawa 3, M.7 EMLA, M.9 EMLA, M.26 EMLA, M.27 EMLA, M.9, MAC 9, MAC 24 and OAR 1 rootstock. Trenches were established parrallel with the tree rows 0.8 m from the center of the trunks on both sides. The trenches were 1.5 to 2 m deep. Grids were constructed 1.2 m deep × 1.8 m wide with 30 cm × 30 cm grid squares. Soil was washed from the profile and the grid was placed over the profile. Roots were classified into 3 size categories; less than 2 mm, 2 to 5 mm and greater than 5 mm. Soil physical properties were also characterized. Differences were found between rootstock root distribution patterns and will be discussed in relation to rootstock and location/soil properties.