bluuebunny/crossref_metadata_2025 huggingface dataset:
Attributes of Water Additives Affect Postharvest Needle Retention of Fraser Fir
Authors: Hinesley L.E. , Blankenship Sylvia M.
Published: February 2019

Cut branches of Fraser fir [Abies fraseri (Pursh) Poir.] were subjected to solutions with different molarity, pH, and solutes. Citrate-phosphate and Na-phosphate buffers induced heavy needle loss at concentrations as low as 10 mm, whereas needle loss was negligible for MES buffer, sucrose solutions, and distilled water. Needle drop increased in response to higher solute concentration and/or greater duration of exposure. Needle loss was almost 100% at pH 3.0 and 9.0, but minimal at pH 6.0 and 7.0. Chemical name used: 2-(N-morpholino) ethanesulfonic acid (MES).
Anatomical Aspects of K, Mn, and Fe Deficiencies in Queen Palm
Authors: Meerow Alan W. , Broschat Timothy K.
Published: February 2019

Anatomical differences in leaves of queen palm [Syagrus romanzoffiana (Chamisso) Glassman] showing visible K, Mn, and Fe deficiency symptoms are described. Potassium-deficient leaves showed less organization in the mesophyll than healthy leaves. Adaxial fibers increased in diameter. Chloroplast frequency was reduced overall, but most severely in areas of the leaf showing gross symptoms of the deficiency. Manganese-deficient leaves had reduced chloroplast frequency, especially in tissue near necrotic areas, and thicker and more fibers per unit length. Iron-deficient leaves had few chloroplasts throughout the mesophyll, and also thicker and more fibers per unit length.
Gibberellic Acid Foliar Sprays Show Promise as Screening Tool for Tomato Fruit Catfacing
Authors: Wien H.C. , Zhang Y.
Published: February 2019

Catfacing of tomato (Lycopersicon esculentum Mill.) fruit describes the enlarged blossom-end scar and ridged, flattened or irregular fruit shape often found on plants subjected to low temperature during ovary development. Experiments were conducted to determine if GA3 foliar sprays could be used as a screening tool for catfacing. Concentrations of 5 to 50 μM of GA3, applied once at transplanting, significantly increased catfacing incidence on the susceptible `Revolution', whereas the resistant `Valerie' was less affected. Two applications 8 days apart extended symptoms to later clusters formed on branches and may be useful for screening cultivars of a wide range of earliness. Plant apex removal may also be possible as a fruit catfacing screening tool. Chemical name used: gibberellic acid (GA3).
Rooting and Acclimatization of Micropropagated Vitis labrusca `Delaware'
Authors: Lewandowski Veronica T.
Published: February 2019

Routine methods were developed to propagate through tissue culture large numbers of Vitis labrusca L. `Delaware' cuttings on a 10-week production cycle. A 35- fold increase in shoots was achieved in 4 weeks through axillary bud proliferation of rejuvenated cultures using a modified Murashige and Skoog (MS) medium. Additive root-stimulating effects from the auxin combination of NAA at 0.001 mg·1iter–1 and IBA at 0.005 mg·liter–1 in half-strength MS resulted in > 95% rooting of microcuttings in 10 days. More than 95% of the rooted plantlets were successfully acclimatized within 14 days using greenhouse flats fitted with humidity domes and containing a fortified soilless growing medium. Leaves from 21-day-old greenhouse plantlets lost 21% water after 40 min of holding at 40% relative humidity, compared to 62% from 9-day-old plantlets and 91% from 3-day-old plantlets. The combined features reported here enable clonal production of ≈ 3000 `Delaware' grape plants per month using simplified methods and reduced intervals between sequential stages of development. Chemical names used: α-naphthaleneacetic acid (NAA), 1H-indole-3-butyric acid (IBA).
Performance of Tissue-cultured Primocane-fruiting Red Raspberries Following Chilling
Authors: Privé Jean-Pierre , Sullivan J. Alan
Published: February 2019

Growth rates for two types of tissue-cultured plant stock for `Heritage', `Ruby', and `Redwing' red raspberry (Rubus idaeus L.) were examined. Actively growing plantlets from the greenhouse (G) were compared to cold-treated (CT) plantlets from cold storage. The greatest differences between these two occurred during the first 6 weeks after planting. At 4 weeks, CT plants for all cultivars had longer canes and internodes, sometimes twice that of G plants. Although `Heritage' had greater total plant dry weights following chilling, `Ruby' and `Redwing' had less. Chilling had no effect on `Heritage' root growth but did reduce root dry weight for `Redwing' and `Ruby'. Relative growth rate (RGR) and leaf area ratio (L-AR) were more effective variables for analyzing growth as they considered differences in initial biomass and cane number and provided a better representation of the data during the initial 6 weeks of growth. All cultivars showed a greater total plant RGR and LAR for the CT plants at 6 weeks. During the first 4 weeks, the G plants were more efficient producers of root dry matter while the CT plants were more efficient producers of cane dry matter. By 6 weeks, the G plants had partitioned a greater percentage of their assimilates into cane growth while the leaves, canes, and roots of the CT plants contributed equally to total RGR. No difference in total or individual component RGR was observed after 6 weeks.
Comparison of Management Techniques for Broccoli Production Using a Systems Approach
Authors: Sterrett S.B. , Coale C.W. , Savage C.P.
Published: February 2019

A systems approach that included production and economic aspects was used to assess broccoli potential as an alternate enterprise for eastern Virginia. Broccoli yield and head quality were improved with 96,400 plants/ha compared to 64,500 plants/ ha. While target populations for the early harvest were achieved with either transplants or direct seeding, plant establishment was significantly reduced for direct-seeding in the main-season harvest (85% vs. 95% for transplants). Increased cost of production with transplants resulted in reduced enterprise profit (before taxes) in the early harvest, while improved plant establishment and increased yield with transplants resulted in increased enterprise profit in the main-season harvest. The systems approach assessed market price risk through estimated revenue and yield risk, providing the information needed by growers for risk management decisions associated with broccoli as an alternate enterprise.
CONTRIBUTION OF CARBON AND NITROGEN RESERVES TO VEGETATIVE AND REPRODUCTIVE GROWTH OF RABBITEYE BLUEBERRY
Authors: Birkhold Keith T. , Darnell Rebecca L.
Published: February 2019

Partitioning of carbon and nitrogen reserves were examined in two cultivars of rabbiteye blueberries (Vaccinium ashei] differing in their timing of vegetative budbreak relative to floral budbreak. Floral budbreak precedes vegetative budbreak in `Climax', while floral and vegetative budbreak occur concomitantly in `Bonita'. Twenty eight containerized plants from each cultivar were dual labeled in the fall with 105 μCi of 14C02 and 0.6 g of nitrogen enriched with 5% 15N. Plants were grown outdoors throughout the winter and the following growing season. At five dates, beginning 27 days prior to full bloom and ending at fruit maturity, plants were harvested into old shoots, roots, fruit, and vegetative growth.

Fall leaf drop accounted for loss of 12% of applied N and 20% of applied 14C. In the first harvest, approximately 73% of the recovered 15N and 50% of the recovered 14C was in the roots for both cultivars. By fruit maturity, approximately 8% of the recovered 15N was in the fruits, 51% in new vegetative growth, and 41% in old shoots and roots. Approximately 1.2% of the recovered 14C was in fruit, 1.5% in vegetative growth, and 97% in old shoots and roots. Data suggest that differences in the timing of vegetative budbreak between these two cultivars do not influence overall partitioning patterns of reserve carbon and nitrogen.
TRICKLE IRRIGATION OF DAY-NEUTRAL STRAWBERRIES USING EVAPOTRANSPIRATION.
Authors: Nonnecke Gail R. , Taber Henry G.
Published: February 2019

The purpose of this project was to investigate the use of evapotranspiration (ET) as a guideline for trickle irrigation timing in field-grown day-neutral `Tristar' strawberry. Proper management of trickle irrigation would allow optimum yields and quality with minimum water inputs. A randomized complete block field design with four replications was used at the ISU Horticulture Station in central Iowa. Irrigation treatments were based on % of ET and number of applications per week. The four treatments included: 30, 60, and 90 % of ET applied once per week (1X) and 30% of ET applied 3 times per week (3X). Total yield data (kg of fruit per season) indicated the 30% of ET (3X) treated plants yielded 15% more fruit than the 30% of ET (1X) plants. Berry number was 14% greater from plants receiving the 30% of ET (3X) treatment than from those receiving the 30% of ET (1X) treatment. Average berry weights for the entire growing season were similar among all treatments.
GAS EXCHANGE CHARACTERISTICS OF FIELD-GROWN `SHAWNEE' BLACKBERRY
Authors: Rom Curt R. , Clark John R.
Published: February 2019

Gas exchange (assimilation, transpiration, water use efficiency, and conductance) of `Shawnee' blackberry were measured under field conditions with a portable system (ADC-IRGA with Parkinson Leaf Chamber). Gas exchange primocane pentifoliate leaflets were similar. Gas exchange rates of leaves along a cane exhibited a quadratic function of leaf position with leaves in lower-mid sections (relative position 0.3 - 0.5) having higher A, TR, WUE, gs than either basal or apical leaves. Leaves subtending fruiting laterals on fruiticanes had higher assimilation than similar age leaves on primocanes but did not differ in Tr, WUE, or gs. Primocanes had estimated dark respiration rates of 0.33mg·dm-1.hr-1, estimated light compensation at 14-20 mol.m-2.s-1, estimated light saturation at 1000-1100 mol.m-2.s-1 with maximum A rates ranging from 24-30 mg CO2.dm-1.hr-1. Measurements were made at field temperatures ranging from 24-35 C. Although temperature response was not measured, correlation indicated that Tr, WUE, and gs were more closely related to temperature than A. Similarly, Tr and WUE were more closely related to gs than A (r = 0.6 to 0.8).
ESTIMATION OF GENETIC RELATIONSHIPS IN THEOBROMA CACAO
Authors: Ronning C.M. , Harkins D.M. , Schnell R.J. , Purdy L.H.
Published: February 2019

Cacao is an important crop in the tropics, but its breeding has been hampered by a lack of understanding of its genetics. One result of this has been the introduction of “hybrid” trees which did not perform predictably under various environmental conditions. We are studying the inheritance of isoenzyme, RFLP, and Random Amplified Polymorphic DNA (RAPD™) markers in order to estimate the genetic relationships among and between populations. Our objectives include determining if any linkage exists between these molecular markers and witches' broom (Crinipellis perniciosa) resistance, a major disease of cacao.
EFFECT OF RELATIVE PLANTING DATE ON INTERCROPPING
Authors: Mergo M. , Rhoden E. G. , Burns M.
Published: February 2019

Intercropping is a management system that maximizes production per unit area of land. Intercropping has to be carried out with crops that are compatible in order to ensure increased productivity. An intercropping study was conducted to determine a suitable planting pattern for corn (Zea mays), an overstory crop, and sweetpotato (Ipomoea batatas), an under-story crop. Five relative planting dates were established for each component crop (3 week; before, 3WB; 2 weeks before, 2WB; simultaneous, SIM; 2 weeks after, 2WA; and 3 weeks after, 3WA planting the other crop). Monocrop of each component was also planted. The marketable yields of sweetpotato were reduced by 48, 57, 75, 76 and 74% when sweetpotato was intercropped with corn and planted 3WB, 2WB, SIM, 2WA and 3WA corn, respectively. Corn grain yields were reduced 28, 28, 26, 57, and 66% when intercropped with sweetpotato beginning 3WB, 2WB, SIM, 2WA and 3WA sweetpotato, respectively. Although yields of individual component crop were reduced in intercrop, there was no significant difference in land utilization. Land equivalent ratio, area time equivalent ratio, and competition ratio were not significantly affected by planting date. Intercropping corn and sweetpotato was compatible when both crops were simultaneously planted.
RIPENING AND STORABILITY OF `LIBERTY' AND `EMPIRE' APPLES
Authors: Autio Wesley R. , Costante Joseph F.
Published: February 2019

Ripening of `Liberty' and `Empire' apples was compared in 1988-90. The internal ethylene of `Liberty' fruit reached 1 ppm approximately 7 to 10 days before `Empire.' `Liberty' and `Empire' fruit both attained acceptable eating quality on approximately 30 Sept. each year. Generally, `Liberty' fruit were firmer and had a higher soluble solids content than `Empire' fruit. Storage properties were compared in 1988 and 1989. In 1988, fruit were harvested at weekly intervals from 20 Sept. to 12 Oct. and kept at 0C for 2.5 months. The firmest fruit of both cultivars were from the 27 Sept. harvest. Fruit of both cultivars harvested on 27 Sept. 1988 retained firmness better when kept at 3.3C, 3% O2, 5% CO2 than when kept at 0C, 3% O2, 2% CO2. Data from 1989 showed that `Liberty' developed large amounts of browncore in controlled atmospheres at either 0C or 3.3C. The incidence of browncore in refrigerated storage declined with later harvests.
MECHANICAL BUD DAMAGE TO BRANCHED AND UNBRANCHED `BRADFORD' PEAR TREES DURING POST HARVEST HANDLING
Authors: Jacyna Tadeusz
Published: February 2019

Branched (B) and unbranched (UB) one-year-old `Bradford'/`OHFx97' trees were examined at intervals between preparation for bare root harvest and long term storage to determine the extent of mechanical bud damage caused by the various handling steps.

After hand stripping of leaves, digging, transportation to the storage facility, and grading, and tying of bundles, there was a marked difference in the percentage of damaged buds between branched (26%) and unbranched (53%) trees. The B/UB live bud ratio before and after harvest was 1:0.45 and 1:0.26, respectively. This difference may have been due to a various morphological growth pattern which both types of trees had produced.
EFFECTS OF MYCORRHIZAE, MEDIA AND CONTAINER TYPE ON THE GROWTH OF GREEN PEPPER AND LETTUCE TRANSPLANTS
Authors: Watson Ray A. , Stewart Katrine A. , Furlan Valentin
Published: February 2019

The effects of two mycorrhizal species (Glomus versiforme and Glomus intraradix) and a control on the growth of green pepper, Capsicum annuum, and lettuce, Lactuca sativa, seedlings have been evaluated using four types of growing media (Peatwool, Fafard bulk mix. Cornell mix and a compost based mix) and two types of containers, Cell Packs (125 cc volume) and Pro-Trays (65 cc volume) for green pepper and Cell Packs (125 cc volume) and Plug Flats (33 cc volume) for lettuce. The experiments were split plot randomized Complete block design with 6 blocks (lettuce) and 4 blocks (pepper). Seeds were sown directly into the containers of mycorrhizal inoculated media. All treatments received the same fertilizer regime.

Cell volume had no significant effects on green pepper fresh weight, dry weight, stem diameter, leaf area or leaf number but the lettuce Cell Pack plants had significantly higher fresh and dry weights, more leaves and higher leaf area. The Fafard Bulk and the Compost mix gave significantly higher fresh and dry weights than did the other two media for both green pepper and lettuce. Mycorrhizal species did not influence plant growth with the exception of leaf area in green peppers and shoot dry weight in lettuce.
AUTOMATED INSPECTION OF FRUITS AND VEGETABLES
Authors: Morrow C. , Heinemann P , Sommer H. , Crassweller R. , Cole R. , Tao Y. , Varghese Z. , Deck S.
Published: February 2019

Research is described on the development of an automated inspection system which uses digital images and artificial intelligence techniques. Procedures have been developed for evaluating size, shape, and color of apples, potatoes, and mushrooms. Current emphasis is being placed on developing algorithms for detection of surface defects. A major effort will also be expended toward the development of an overall “quality” score for automated inspection of fruit and vegetables. The automated results are compared with those obtained using conventional manual inspection methods. Apples, potatoes, and mushrooms are the primary crops being inspected although the algorithms and techniques are applicable to many different fruits and vegetables. Color and monochromatic image processing components in “MS-DOS” and “Macintosh” computers are being used in this study.
EFFECTS OF COMPACTION ON SUBSTRATE CO2 IN A SUBIRRIGATION SYSTEM
Authors: Khoury Noreen S. , Holcomb E. Jay
Published: February 2019

Greenhouse substrates are designed to allow maximum aeration. Substrate water holding capacity can be increased by media compaction.

Six inch standard pots, fitted with gas tight openings for removing gas samples, were filled with Metromix 350 and Peatwool at 2 different compaction rates. Half the pots were planted with rooted cuttings of Poinsettia pulcherrima `Glory' and half were left fallow. Air samples were taken at both wet and dry soil moisture conditions at early, mid point and at the end of the cropping cycle. In general, wet substrates had higher CO2 than drier substrates and more compacted substrates had higher CO2 than less compacted.

CO2 decreased with time in all treatments. The highest CO2 levels occurred in wet heavily compacted Peatwool with a plant and the lowest occurred in dry Metromix with no plant.
PURIFICATION AND SOME PROPERTIES OF ALPHA-AMYLASE OF PEAR FRUIT
Authors: Li Shiao J. , Facteau Tim , Chen Paul M.
Published: February 2019

Alpha-amylase was purified from freeze-dried pear fruit by extraction at pH 7.40 with Tris, Acetate and Imidazole buffer followed by differential ammonium sulfate precipitation and desalting column. The specific activity of the enzyme was increased 5.68 fold during purification. The optimum pH was 5.64 in Acetate buffer. The difference in the time course of alpha-amylase was observed between freeze-dried and fresh samples.
MARKET GARDENING RESEARCH AND DEVELOPMENT IN THE GAMBIA
Authors: Beverly R.B. , George Sonni , Gaye G.O.
Published: February 2019

Vegetable gardening in The Gambia provides an important supplemental income for women farmers who grow tomato, onion, cabbage and other vegetables for sale on the local market, to restaurants and for export to Europe. Government and international agencies provide research and technical support, while non-governmental organizations (NGO's) provide production capital (such as wells) and marketing support. Production problems include pest management and the labor intensity of hand irrigation and harvesting. Growers cite low prices as their greatest constraint. Small local canning facilities may help alleviate market gluts and extend marketing and consumption opportunities beyond the fresh market production season.
IN VITRO ORGANOGENESIS OF `BEAUREGARD' SWEETPOTATO
Authors: Rivas Roberto A. , Evans P.T. , LaBonte D.R.
Published: February 2019

Methodology is presented for organogenesis of `Beauregard sweetpotato, a cultivar released in 1987 that is rapidly increasing in commercial use in the U.S. Regeneration of `Beauregard' sweetpotato plantlets was obtained when complete leaves and 10 mm internode explants were cultured in liquid and solid media respectively over a period of 8 weeks. Leaves in liquid Murashige and Skoog medium containing 2 mg/l of IAA placed on a shaker under dark conditions produced white callus at the cut end of the petiole and roots underneath the callus in 4 weeks. Leaves were subsequently transferred to MS medium containing 500 mg/l of Chlorocholine chloride (CCC) and 0, 1, 5 and 10 mg/l of BAP for 4 more weeks. Shoots were regenerated from callus using 1 mg/l of BAP.

The effect of NAA auxin and various concentrations of the cytokinin Thidiazuron on internodes was examined under 16 hr. light and 8 hr dark photoperiod using MS solid medium. Explants on 0.05 mg/l NAA alone produced roots and shoots. The most plantlets however, were regenerated using 0.05 mg/l of NAA and 0.01 mg/l Thidiazuron. Regeneration of plants from leaves and internodes may be a useful system for a clean and rapid propagation of `Beauregard' sweetpotato.
CARBOHYDRATE METABOLISM IN TOBACCO CULTIVARS DURING SHIFTS IN GROWTH TEMPERATURE
Authors: Steffen Kenneth L. , Sims John L. , Bush Lowell P.
Published: February 2019

This study examined the effect of shifts in growth temperature on: 1) the partitioning of carbohydrate into starch or sucrose; and 2) the differential responses of tobacco types which differ in starch accumulation capacities. Six-week-old tobacco seedlings of Speight G28 (G28), a fluecured cultivar, and Ky 14 (K14), a burley cultivar, were acclimated for 9 days in growth chambers to a 14 h photoperiod of 300 μmol/s-m2 PAR at 27/22 C (day/night) and a relative humidity of between 70-80%. Temperature was then shifted to 15/10 C for 13 days and then back to 27/22 C for 8 days. At all points, sucrose, starch and protein content was higher in G28. Both cultivars demonstrated significant increases in dry matter accumulation per area, 1 day after the shift to 15/10 C. Dry matter increased steadily through day 13 in G28, but increased to day 5 and then leveled off at day 13 in K14. Nearly identical patterns of sucrose accumulation were observed in both species, with marked increases to day 5 and then a dramatic decline at day 13. Starch content increased steadily from day 1 to day 13 in G28, but leveled off in K14 after day 5. At day 8, soluble protein content increased only slightly in K14, but increased nearly 2-fold in G28. Within 1 day of the return to 27/22 C, starch and sucrose levels in both cultivars dropped 2 to 5-fold, to pre-temperature shift levels. The significance of these finding will be discussed.
ENDOGENOUS IAA AND WATER UPTAKE IN DEVELOPING COFFEE FLOWER BUDS
Authors: Schuch Ursula K. , Miller Anita N. , Fuchigami Leslie H.
Published: February 2019

Dormant coffee (Coffea arabica L.) flower buds require water stress to stimulate regrowth. A xylem specific watersoluble dye, azosulfamide, was used to quantify the uptake of water by buds after their release from dormancy by withholding water. In non-stressed flower buds, the rate of water uptake was generally slower and variable. In stressed flower buds, the rate of uptake tripled from one day to 3 days after rewatering and preceded the doubling of fresh and dry weight of buds. Free, ester, and amide IAA levels of developing flower buds were measured by GCMS-SIM using an isotope dilution technique with [13C6] IAA as an internal standard. Throughout development, the majority of IAA was present in a conjugated form and the dominant form was amide IAA. The proportions of amide and free IAA changed rapidly after plants were water stressed until day 3, and preceded the doubling of fresh and dry weight. Correlation coefficients of 0.9, 0.7, and 0.7 (p<0.l) were found between auxin content and fresh weight, dry weight, and rate of water uptake, respectively.
ROOTSTOCK GROWTH AFFECTED BY CROPPING LEVEL UNDER LOW SOIL-MOISTURE CONDITIONS IN SEYVAL GRAPEVINES
Authors: McLean M. , Howell S. , Flore J.A. , Smucker A.J.M.
Published: February 2019

Both berries and roots of grapevines are powerful carbohydrate sinks. However, during periods of soil-moisture stress, the relative strength of these two sinks is not known. This experiment was conducted to evaluate interrelationships between differing crop loads on carbohydrate partitioning for above and below-ground tissues. Root development, depth, and rate of turnover were determined by quantifying root images from video recordings taken to depths of 75 cm at two week intervals throughout the growing season. Two-year old own rooted Seyval grapevines, and Seyval grafted to 5-BB and Seyval, were grown under a rain exclusion shelter and provided with 10 or 2.5 liters of water/plant/week. Treatments were cropping level, either 0 or 6-clusters/vine. Shoot length, number of mature nodes, and dry leaf weight of vines under high cropping level were significantly reduced compared to vines growing under the low cropping level; so was root number and depth of root penetration. These data suggest that conditions of low soil moisture result in carbohydrate partitioning in favor of the clusters at the expense of the roots.
ANATOMY OF CHLOROTHALONIL-INDUCED GRAPE BERRY RUSSET
Authors: Goffinet Martin C. , Pearson Roger C.
Published: February 2019

Clusters of Vitis labruscana cv. Concord were grown either in full sun or canopy shade, and either not sprayed or sprayed with 3.4 Kg/Ha chlorothalonil every 2 wk from pre-bloom to veraison. Only sun-exposed, sprayed fruit produced skin russeting. Clusters of the very susceptible V. vinifera cv. Rosette were grown in direct sun, sprayed with chlorothalonil 4 times from bloom to veraison, in the presence or absence of purported anti-russeting agents. Heavy russet occurred in all treatments. Russet initiation was similar in the 2 cvs.: epidermal cells first died beneath spray residue in full sun, a phellogen then arose in the hypodermis, followed by periderm. Epidermal death began in `Rosette' within a wk of the bloom spray, but in `Concord' only after 2-3 wk post bloom and 3 sprays. `Concord' russet generally appeared as patches or scabs, whereas `Rosette' russet ranged from freckles, welts, scabs to large smooth burnished areas. In both cvs., unbroken russet consisted of uniform layers of phellum. New, deeper periderm initials arose beneath checks and cracks which formed as fruit enlarged. In `Concord', but not `Rosette', the daughter cells of each such initial were often enclosed in the original cell wall. In all cases of russet, cell walls in the periderm were suberized and sometimes lignified. Cells also contained much phenolic material.
INFLUENCE OF SUPRAOPTIMAL ROOT-ZON E TEMPERATURES ON RUBISCO ACTIVITY, CHLOROPHYLL AND CAROTENOID LEVELS IN `ROTUNDIFOLIA' HOLLY
Authors: Ruter John M. , Ingram Dewayne L.
Published: February 2019

High root-zone temperatures have been shown to affect photosynthate partitioning, respiration, nitrogen nutrition and growth of `Rotundifolia' holly. The loss of chlorophyll and protein in shoots of other plants in response to high root-zone temperatures has been documented. Therefore, the objectives of this research were to look at the effects of supraoptimal root-zone temperatures on RUBISCO activity, leaf protein and photosynthetic pigment levels.

Soluble protein levels in leaves increased linearly as root-zone temperature increased from 30 to 42 C. RUBISCO activity per unit protein and per unit chlorophyll responded quadratically to root-zone temperatures. Total chlorophyll, chlorophyll a & b, and carotenoid levels decreased linearly with increasing root-zone temperature. It is possible that `Rotundifolia' holly was capable of redistributing nitrogen to maintain RUBISCO activity for photosynthesis.
GROWTH AND YIELD OF PEPPER TRANSPLANTS AND DIRECT-SEEDED PLANTS
Authors: Leskovar Daniel I.
Published: February 2019

Pepper cv. `Jupiter' plants were field-grown from containerized transplants produced with either overhead (SPl) or sub-flotation (SP2) irrigation, or from direct seeding, in 3 years. Shoot and root growth were measured at frequent intervals. At planting, SPl transplants had larger basal root length and numbers than SP2 transplants. At the end of the growth period, basal, lateral, and taproot dry weights accounted for 81, 15, and 4% of the total for transplants, and 25, 57, and 18% of the total for direct-seeded plants. The coordination of growth (linear logarithm relationship) between root and shoot, changed after fruit set only in transplants. Over all seasons, transplants exhibited significantly higher yields than direct-seeded pepper plants.
GROWTH OF A LETTUCE CROP IN NASA's BIOMASS PRODUCTION CHAMBER
Authors: Wheeler R.M. , Mackowiak C.L. , Sager J.C. , Vieux B. , Knott W.M.
Published: February 2019

Lettuce (Lactuca sativa cv. Waldmann's Green) plants were grown in a large, tightly sealed chamber for NASA's Controlled Ecological Life Support Systems (CELSS) program. Plants were started by direct seeding and grown in 64 0.25-m2 trays (six plants per tray) using nutrient film technique. Environmental conditions included: 23°C, 75% relative humidity, 1000 ubar (ppm) CO2, a 16/8 photoperiod, and 300 umol m-2 s-1 PPF from metal halide lamps. Although the chamber was typically opened once each day for cultural activities, atmospheric ethylene levels (measured with GC/PID) increased from near 15 ppb at 23 days after planting (DAP) to 47 ppb at 28 DAP. At harvest (28 DAP), heads averaged 129 g FW or 6.8 g DW per plant, and roots averaged 0.6 g DW per plant. Some tipburn injury was apparent on most of the plants at harvest. By 28 DAP, stand photosynthesis rates for the entire chamber (approx. 20 m2) reached 17.4 umol CO2 m-2 s-1, while dark-period respiration rates reached 5.5 umol CO2 m-2 s-1. Results suggest that good yields can be obtained from lettuce grown in a tightly sealed environment.
DIURNAL FLUCTUATIONS IN SIZE OF TOMATO FRUIT
Authors: Diaz-Perez Juan Carlos , Shackel Kenneth
Published: February 2019

Tomato fruits showed diurnal fluctuations in size in addition to long-term irreversible enlargement. Diurnal fluctuations were highly related to the stage of fruit development. In all stages, the maximum relative growth rate occurred in the morning and the minimum RGR at midday. Midday depression of RGR became more severe as fruits developed. In young fruits, RGR was nearly constant over the day. A small depression in growth was observed only at midday. In more developed fruits, RGR was positive during the first half of the day, followed by near zero values in the afternoon, and a. recovery in early night. In mature fruits, overall fruit growth was minimum and RGR was positive only in the morning. Fruit shrinkage was often seen at midday in mature fruits.
RELATIONSHIP BETWEEN FUNGAL HORMONE PRODUCTION AND ECTOMYCORRHIZAL INFECTION OF PINUS MUGO
Authors: DeVries Henry E. , Lardner Joseph P. , Mudge Kenneth W.
Published: February 2019

To test the hypothesis that phytohormone production is related to mycorrhizae formation 29 isolates of ectomycorrhizal fungi have been evaluated for production of ethylene and auxin in pure culture and for their ability to form ectomycorrhizae with Pinus mugo. The fungi tested included a series of monokaryotic isolates of Laccaria bicolor and dikaryotic isolates of Amanita muscaria, Hebeloma crustuliniforme, L. laccata, L. proxima, Pisolithus tinctorius, Rhizopogon ellenae, and R. vinicolor. Inoculated root systems were rated for mycorrhizae formation, root/shoot ratio and root morphology. P. tinctorius isolates which formed abundant mycorrhizae produce no ethylene in vitro, but did produce the auxin IAA. L. bicolor isolates produced ethylene as well as auxins putatively identified as IAA, and IBA. Correlations between phytohormone production and mycorrhizogenicity will be presented.
FURTHER INVESTIGATIONS INTO GARLIC STERILITY AND SEED PRODUCTION
Authors: Pooler Margaret , Simon P.W.
Published: February 2019

Garlic (Allium sativum L.) is an obligate apomict which reproduces almost exclusively by means of division of underground cloves or by propagation of topsets. The occurrence of viable, sexually-derived garlic seeds is rare. In order to assess the factors that limit garlic seed production, variables that affect flower initiation and development were studied. The effects on flowering of daylength, growing temperature, bulb and plant cold storage conditions, and cultivar were examined by observing flower development in plants grown under controlled greenhouse conditions. Correlations between isozyme markers and flowering, fertility, and morphological markers will be presented for a diverse collection of garlic clones, including six sexually-derived garlic plants.
INFLUENCE OF RESTRICTED ROOT-ZONE VOLUME ON SHOOT BEHAVIOR
Authors: Krizek Donald T.
Published: February 2019

Roots exposed to drying soil have been shown to generate non-hydraulic signals which can be communicated to the shoot. Such `root signals' can cause an inhibitory effect on leaf growth without causing detectable water deficits in the shoots. Plants grown in restricted root zone volumes also typically show a reduction in leaf and shoot growth. Although water stress and root restriction both impair growth, their effects on photosynthesis, leaf initiation, and C, N, and P metabolism may be quite different. Abscisic acid (ABA) has been shown to be produced in the roots after only mild dehydration and to play a major role in signal transduction from the roots to the shoots. Whether root-restricted plants are capable of generating `root signals' such as ABA or other plant hormones, which can be communicated to the shoot, remains to be determined. The application of new tools, such as gas chromatography/mass spectrography for hormone analysis, nuclear magnetic resonance imaging, and photoacoustic spectroscopy, should help to identify the nature of `root signals' generated during root restriction and clarify their regulatory role in shoot behavior.
PUBLIC RISK PERCEPTIONS
Authors: Hock Winand K.
Published: February 2019

One of the major misconceptions in contemporary society is the widespread belief that our food supply is unsafe. The public's perception of risk is quite different than scientific assessment of risk. While scientists see microbial contamination as the key issue (100 to 10,000X greater risk than from exposure to pesticide residues), consumers appear to be most concerned about the effects of synthetic pesticides and fertilizers in the food they buy. Consumers equate “synthetic” with harmful or bad and “natural” with safe or good, yet they ignore the fact that 99.9% of all pesticides humans are exposed to are naturally occurring. Americans eat approximately 1.5 g. of natural pesticides per person per day, or about 10,000 times more than synthetic pesticide residues. Although few plant toxins have been tested for carcinogenicity so far, of those tested about half are rodent carcinogens. Contrary to public perception, environmental pollution accounts for only 2% of all cancers. By contrast, smoking, diet and other personal lifestyle choices account for more than 75%.
OVERVIEW OF SOCIAL SCIENCE RESEARCH METHODOLOGY IN HORTICULTURE
Authors: Warland Rex H.
Published: February 2019

During this presentation, several basic issues related to survey research will be introduced and illustrated. First several issues related to sampling will be considered. These will include how to determine sample size, where to obtain a sampling frame, how to compute error rates, and how to estimate costs associated with sampling. Mail surveys, telephone surveys, and face-to-face interviews will then be described and compared. The state of the art of these methods will be discussed, the costs associated with each method will be reviewed, and the advantages and disadvantages of each method will be described. Response rates will also be discussed. Next we will briefly review the kinds of information that can and cannot be obtained from a survey. Several principles concerning question wording, question order, and question context will be introduced. The presentation will conclude with a few suggestions about the linkages between surveys and statistical analysis.
Objective and Sensory Evaluation of Fresh Fruit of Day-neutral Strawberry Cultivars
Authors: Reitmeier Cheryll A. , Nonnecke Gail R.
Published: February 2019

Sensory and objective attributes of fresh fruit of five locally grown day-neutral strawberry (Fragaria × ananassa Duch.) cultivars (Tristar, Tribute, Mrak, Yolo, and Selva) were compared to those of California-grown strawberries available in the Iowa markets. `Tristar' and `Tribute' fruit were redder and more sour than fruit of other day-neutral cultivars, and `Tristar' fruit were the most juicy of the berries evaluated. `Tristar' and `Tribute' fruit had higher titratable acidity and lower Hunter L (lightness) values than those of other evaluated fruit. Sensory panelists rated the California-grown berries as the least red.
Response of Spring and Summer-harvested Asparagus to Harvest Pressures
Authors: Dufault Robert J.
Published: February 2019

The objective of this study was to determine the effect of cutting pressures on fern and crown growth of spring- and summer-harvested asparagus (Asparagus officinalis). Two-year-old `UC 157 F1' asparagus seedlings, grown outdoors in 57-liter pots, were harvested for the first time in spring (Mar. 1988) or summer (July 1988) at cutting pressures of three, six, nine, or 12 spears/plant. Fern was mowed to encourage spear emergence in summer. Cutting pressures had no effect on spear diameter in either season. Summer harvesting required 52% less time to complete than spring harvesting. Fern of spring-harvested plants lived 63 days longer than fern emerging after summer harvests; cutting pressure had no effect on fern lifespan. By Nov. 1988, crown quality and growth, harvest times, and storage root carbohydrates were similar among all cutting pressures; however, carbohydrate content was higher in summer-harvested than spring-harvested crowns. Crowns were cold-stored during Winter 1988 and planted in the field in Spring 1989. Plants harvested in Summer 1988 produced 21% more fern in Summer 1989 than those harvested in Spring 1988. Fern production in 1989 was similar for all cutting pressures.
Flowering of Aeschynanthus `Koral'
Authors: Whitton Brooks , Healy Will , Roh Mark
Published: February 2019

Aeschynanthus `Koral' plants were grown in photoperiods of 8 to 14 hours (8 hours of natural daylight plus 0 to 6 hours of incandescent light of 3 μmol·m-2s-1) beginning January, March, or June. The number of weeks to anthesis and the number of leaves on flowering shoots were not affected by photoperiod but differed based on when treatments commenced. Flowering was inhibited, regardless of photoperiod, when the daily temperature differential was larger than 10C. To study the interaction of photoperiod and temperature, Aeschynanthus `Koral' plants were grown under photoperiods of 12 or 24 hours (daylight fluorescent lamps at 4.3 mol·m-2·day-1) at 18 or 24C. After 8 weeks, plants grown at 18C had fewer nodes before the first flower bud than plants grown at 24C. Aeschynanthus `Koral' was day-neutral at 18C, but responded as a long-day plant at 24C.
Gibberellic Acid-induced Seedlessness in Field-grown Vines of `Swenson Red' Grape
Authors: Fellman Cynthia , Hoover Emily , Ascher Peter D. , Luby James
Published: February 2019

We evaluated the extent to which `Swenson Red' seeded grape (Vitis × spp.) responded to single and repeated GA3 applications to induce seedless fruit development. Field studies were conducted to test the time of pre-anthesis GA3 application (18, or 24 May or 3 June), the usefulness of postanthesis application, the optimum GA3 concentration (0, 0.075, 0.15, or 0.3 mm), and the method of application. The treatment dates that gave a high percentage of seedless berries with an acceptable berry count per cluster were 24 May with postanthesis application and 3 June pre-anthesis only. The optimum GA3 concentration was 0.15 mm applied both before and after anthesis. The most seedless berries developed when pre- and postanthesis applications were used, indicating many seedless fruit developed from flowers that would have abscised. There was no difference in percent heedlessness, number of berries per cluster, or number of seeds per berry between clusters dipped or sprayed with 0.3 mm GA3. Chemical uame used: gibberellic acid (GA3).
Uniconazole Suppresses Bypass Shoot Development and Alters Flowering of Two Forcing Azalea Cultivars
Authors: Keever Gary J. , Foster William J.
Published: February 2019

`Redwings' and `Gloria' azaleas (Rhododendron × `Redwings' and `Gloria') were treated with foliar sprays of uniconazole, paclobutrazol, or daminozide to suppress bypass shoot development and promote flower initiation and development. Uniconazole at 5 and 25 mg·liter-1 suppressed bypass shoot development of `Redwings' and `Gloria', respectively. Flowering of `Gloria', but not `Redwings', was delayed slightly with uniconazole sprays up to 25 mg·liter-1; with the highest uniconazole concentration, 200 mg·liter-1, flowering was delayed as much as 18 days. Flower count of `Gloria' was not affected by lower concentrations of uniconazole, but it was greatly reduced in both cultivars with concentrations above 75 mg·liter-1. Uniconazole was more active than paclobutrazol sprays of similar concentrations or than two daminozide sprays of 3000 mg·liter–1. Chemical names used: (E)-1-(p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol (uniconazole); (2RS,3RS)-1-(4-chlorophenyl)-2-(1,1-dimethylethyl)-(1H-1,2,4,-triazol-l-yl-)pentan-3-ol (paclobutrazol); butanedioic acid mono(2,2-dimethylhydrazide (daminozide),
Rapid Measurement of Diffusion of Gas Through the Skin of Apple Fruits
Authors: Knee Michael
Published: February 2019

A method was devised for measuring the resistance to gaseous diffusion of bulky plant organs, such as apple (Malus domestica Borkh.) fruits, in which the skin is the major barrier to diffusion. An individual fruit was incubated in a sealed container in the presence of a measured concentration of ethane for a certain time (usually 20 min). The fruit was then transferred to another, similar container. The ethane concentration that diffused into the new container was measured after an equal time (usually 20 min). An expression relating resistance to the measured ethane concentrations was derived from Fick's First Law of diffusion. An estimate of the internal volume of the fruit, accessible to ethane, was also necessary. The method was tested on several fruits of various apple cultivars. Longer incubation periods are necessary for apples with high diffusive resistance.
Chromosome Analysis of Alstroemeria ligtu Hybrids
Authors: Rustanius Patricia , Hang A. , Hughes H.G. , Tsuchiya T.
Published: February 2019

Five color types of Alstroemeria ligtu Linn hybrids from one seed source were examined cytogenetically. The somatic chromosome numbers were all 2n = 2x = 16. Karyotype analysis revealed that all five plants had the same chromosome constitution. Chromosome pairs 2,3,5, and 8 had satellites. Chromosome complements of the A. ligtu hybrid were unique in that they contained two pairs of satellite metacentric chromosomes that were not found in any Alstroemeria cultivars.
Plant Regeneration from Cotyledons of Cucumis melo `Topmark'
Authors: Chee Paula P.
Published: February 2019

A procedure for the regeneration of muskmelon (Cucumis melo L.) cv. Topmark via shoot organogenesis from cotyledon explants is described. The best induction medium for a morphogenic response was MS salts and vitamins medium with BA at 1.0 mg·liter-1. Further vegetative bud development was completed by transferring organogenic tissue to MS medium containing BA at 0.05 mg·liter-1. The shoots were rooted in MS medium containing NAA at 0.01 mg·liter-1. Morphologically normal plantlets were obtained. Chemical abbreviations used: 6-benzylaminopurine (BA); indoleacetic acid (IAA); naphthaleneacetic acid (NAA).
Regeneration of Spinach from Leaf Callus
Authors: Al-Khayri Jameel M. , Huang Feng H. , Morelock Teddy E.
Published: February 2019

Callus, induced in the dark from leaf tissue of spinach (Spinacia oleracea L. cv. Fall Green) on Murashige and Skoog (MS) medium supplemented with (in mg·liter -1) 2 kinetin and 0.5 2,4-D regenerated shoots upon transfer to a medium containing 2 kinetin, 0.01 2,4-D, and 1 GA3. Complete plants were established by stimulating rooting of the shoots with 1 mg IBA/liter and transferring them to potting soil; survival was 60%. Chemical names used: N-(2-furanylmethyl)-1H-purin-6-amine (kinetin); 2;4-dichlorophenoxy acetic acid (2,4-D); gibberellic acid (GA3); 1H-indole-3-butanoic acid (IBA).
Germination and Regeneration of Plants from Old Cucumber Seed
Authors: Ali Nawab , Skirvin Robert , Splittstoesser Walter E. , George William L.
Published: February 2019

Cucumber (Cucumis sativus L.) seeds of `Marketer', `Marketmore', `Wisconsin SMR-18', `Tablegreen', `Spotfree', and `China' were stored at 3C and 38% relative humidity for up to 26 years. Seed older than 13 years did not germinate. Cultivars stored 10 years gave 80% germination, except Wisconsin SMR-18' (40%). Ten-year-old seeds were separated from their seedcoats, and cotyledons were excised into six segments. Explants were placed on Murashige and Skoog medium with all combinations of BAP (0, 1,2, and 3 mg·liter-1) and NAA (0, 0.1,0.2, and 0.3 mg·liter-1). Plants were obtained from culture for all cultivars grown on medium containing NAA and 1 mg BAP/liter. No plants were regenerated when BAP or NAA was lacking. Chemical names used: benzylaminopurine (BAP), 1-naphthaleneacetic acid (NAA).
Onion Plant Growth, Bulb Quality, and Water Uptake following Ammonium and Nitrate Nutrition
Authors: Gamiely S. , Randle W.M. , Mills H.A. , Smittle D.A. , Banna G.I.
Published: February 2019

Nitrogen applied as NH4-N or NO3-N (75 mg·liter-1) affected onion (AIlium cepa L.) plant growth when grown in solution culture. Nitrate alone or in combination with NH4-N increased leaf fresh and dry weight, leaf area, root fresh and dry weight, and bulb dry weight when compared to growth with NH4-N as the sole N source. Bulb fresh weight was highest with an NH4-N: NO3-N ratio between 1:3 and 3:1. Maximum leaf fresh weight was not necessary to produce maximum bulb fresh weight when onions were subjected to different N-form ratios. Precocious bulbing resulted when NH4-N was the sole N source; however, high bulbing ratios early in plant development were not correlated with final bulb fresh weight. Nitrogen form also influenced water uptake and pungency, as measured by enzymatically developed pyruvate concentration, but did not affect bulb sugar concentration.
Calcium Inhibition of Polyacrylamide Gel Hydration Is Partially Reversible by Potassium
Authors: Bowman Daniel C. , Evans Richard Y.
Published: February 2019

Hydration of a commercial hydrophilic polyacrylamide gel in 20 meq Ca(NO3)2/liter was reduced to <10% of the maximum hydration in deionized water. Repeated soaking with deionized water to remove soluble salts restored hydration to ≈ 30% of maximum. Incorporating KNO3 at concentrations ranging from 5 to 40 meq·liter-1 with the Ca(NO3)2 in the hydration solution partially reversed the Ca2+ inhibition of hydration following repeated soaking. Potential hydrogel hydration increased to 50% of maximum with 40 meq K+/liter. Potassium nitrate supplied separately following hydration in Ca(NO3)2 was much more effective at reversing Ca2+ inhibition of hydrogel hydration than joint application. Potential hydrogel hydration (following repeated soaking) was doubled after treatment with 5 meq KNO3/liter and reached 77% of maximum at 40 meq KNO3/liter.
Genetics of Semideterminate Growth Habit in Tomato
Authors: Elkind Yonatan , Gurnick Arie , Kedar Nachum
Published: February 2019

The objective of this study was to elucidate the genetic control of the semideterminate growth habit in tomato (Lycopersicon esculentum Mill.). A semideterminate tomato line was crossed with determinate and indeterminate lines; their F1, F2, and backcrosses were grown; and the growth habit recorded and analyzed. Plants with six or more inflorescences on the main stem were defined as semideterminate, while those with fewer were defined as determinate. The F2 and backcross to determinate were bimodal, indicating a single recessive gene for semideterminate, which was denoted as sdt. The goodness-of-fit chi square for a single recessive gene model was 88% and 69% for F2 and backcross generations, respectively. In the cross between semideterminate and indeterminate types, the results indicated control by two genes, sp and sdt, with the sp+ indeterminate type epistatic over semideterminate. The goodness-of-fit to this model was 70% and 82% for F2 and backcross generations, respectively.