bluuebunny/crossref_metadata_2025 huggingface dataset:
MYCORRHIZAE AND NONHYDRAULIC SIGNALLING IN SORGHUM EXPOSED TO PARTIAL SOIL DRYING OR ROOT EXCISION
Authors: Ebel Robert , Duan Xiangrong , Stodola Ann , Augé Robert
Published: April 2024

Our objectives were to determine (a) if mycorrhizal (VAM) fungi can alter drought-induced, nonhydraulic regulation of shoot growth, and (b) how much of a root system can be dried or severed before hydraulic effects on shoot responses become evident. Sorghum was grown with roots equally divided among four pots. The 2×2×4 factorial design had two levels of mycorrhizae (± Glomus intraradix), two levels of root treatment (dried or severed) and four levels of amount of roots treated (0, 1, 2 or 3 pots dried or severed). Neither leaf water potential (Ψ) nor Cs were affected by drying 1 or 2 pots, and reductions in leaf area in these plants were therefore attributed to nonhydraulic signalling. When 2 pots were dried, leaf growth was reduced less in VAM than in nonVAM plants, despite lower P in VAM leaves and despite quicker soil drying by VAM roots. Drying or severing roots of 3 pots did result in drops in leaf Ψ and Cs, indicating a likely hydraulic effect on leaf water status in those plants. Leaf P declined progressively as more roots were dried or severed, possibly also affecting growth in plants with roots in 3 pots dried or severed. Leaf extension rates (LER) declined with only slight drops in soil Ψ, and LER declines were related to volume of soil drying. In VAM plants, leaf area reductions were correlated with length of time roots were exposed to soil Ψ between -0.02 and -0.50 MPa.
MYCORRHIZAL SYMBIOSIS AND NONHYDRAULIC SIGNALLING OF SOIL DRYING IN CORN GIVEN VARIED P FERTILIZATION
Authors: Augé Robert , Duan Xiangrong , Ebel Robert , Stodola Ann
Published: April 2024

In Zea mays L. plants grown with roots divided between two pots, we tested (a) if leaf P concentration can affect nonhydraulic root to shoot signalling of soil drying, and (b) if a mycorrhizal (VAM) effect on signalling can occur independently of a VAM effect on leaf P. The 2×3×2 factorial design had 2 levels of mycorrhizae (± Glomus intraradix Schenck & Smith), 3 levels of P fertilization and 2 levels of water (both pots watered, or one pot watered while the other was allowed to dry). Total leaf length and shoot dry weight were not reduced in half-dried VAM plants, but each measure was ultimately reduced about 10% in half-dried nonVAM plants. Stomatal conductance (Cs), unaffected by VAM, was lower in half-dried, high-P plants than in high-P controls a few times during the latter half of the experiment, by as much as 65%. Leaf water potentials were not affected by partial soil drying, and reductions in leaf growth preceded reductions in Cs; hence, growth reductions were attributed to nonhydraulic signals coming from roots in drying pots. VAM × water and P × water interactions indicated that mycorrhizae influenced signal effects on final plant leaf length and that P fertilization influenced signal effects on Cs. Soil water potential, measured every 2 h with heat dissipation sensors, showed that soil drying was not affectd by VAM or P treatment.
DIURNAL WATER RELATIONS OF PLUM EXPOSED TO DIFFERENT ATMOSPHERIC OZONE PARTIAL PRESSURES.
Authors: Retzlaff W.A. , Williams L.E. , DeJong T.M.
Published: April 2024

Japanese plum (Prunus salicina Lindel., `Casselman') trees were enclosed in open-top chambers on 1 May 1989 and exposed to three atmospheric ozone partial pressures (charcoal-filtered air [CF], ambient air [AA], and ambient air+ozone [AO]) during the growing season in 1989, 1990, 1991, and 1992. The mean 12-h (0800-1900 HR PDT) ozone partial pressures during 1992 were 0.027, 0.045, and 0.087 μPa Pa-1 in the CF, AA, and AO treatments, respectively. Both stem and leaf water potential (Ψ) decreased from 0700 to 1600 HR PDT and were lowest at midday (1200-1400 HR PDT) in all ozone treatments. Leaf and stem were equivalent at predawn, but leaf Ψ was lower than stem Ψ during the diurnal period. Midday stem Ψ was greater in the AA and AO treatments compared to the CF treatment. Before 1 Aug., stomatal conductance of trees in the AO treatment was reduced compared to the CF treatment, but diurnal fluctuations were similar between the two treatments. Following 1 Aug., stomatal conductance of trees in the AO treatment was reduced compared to the CF treatment, but stomatal conductance of the AO treatment remained the same throughout the day. Trees in the AO treatment had greater leaf fall earlier in the growing season than those of the other treatments. Changes in plum tree stem Ψ under chronic ozone stress are probably due to a loss (early senescence) of transpiring leaf area as well as declines in stomatal conductance.
CHANGES IN THE RESISTANCE TO WATER MOVEMENT THROUGH THE SOIL/PLANT PATHWAY IN SALINIZED SUNFLOWER (HELIANTHUS ANNUUS L. GIGANTEUS).
Authors: Balint D.E. , Zajicek J.M. , Drew M.C.
Published: April 2024

The water potential gradient through the plant and the resistance to the viscous flow of water are two properties that may be affected by salinity stress within a plant. In this study, sunflowers in sand culture were irrigated with various concentrations of NaCl up to 75 mM. The concentration of NaCl was gradually raised to avoid osmotic shock and the Ca2+ concentration was maintained at 4.0 mM. Non-destructive techniques such as stem-flow gauges, psychrometers, porometry and weighing were used to determine changes in the resistance to flow and the pattern of water movement. Estimates of water potential were obtained for the rooting medium, the xylem at the shoot-root junction, and the upper leaves. From measurements of transpiration values, resistance to water flow across the roots, and between roots and leaves could be calculated. At 5 and 6 days of salinization, there were increases in the resistance to water flow across roots at the 75 mM salt level. This was accompanied by an increase in stomatal resistance to water vapor. These results suggest that moderate increases in salt level markedly affect the water relations of sunflower.
632 (PS 3) SEWAGE SLUDGE INCREASES YIELD AND COLOR OF PERRENNIAL RYEGRASS WHEN ADDED TO YARDWASTE COMPOSTS
Authors: Downer Jim , Pittenger Dennis , Faber Ben , Rogers Paul
Published: April 2024

Greenwaste from California landscapes has been disposed of in landfills for many years. Legislation now requires reduction of disposal by 25% in 1995 and 50% by 2000. Our goal was to find a sewage sludge(SS) rate which would most enhance yardwaste (YW) amendments. YW was co-composted with (SS) at ratios of: YW:SW 100:0, 95:5, 85:15, 75:25, and 50:50. Fresh YW and composts were blended (30% vol.) with clay, loam and sand soils, added to 3.71 containers and seeded with Manhattan II perennial ryegrass. Germination was greatest in unamended soil, but reduced 50% in soils with the 50% SS amendment, yet this treatment had the best turfgrass color ratings. Clipping yield was highest in sludge amended soils (Chart).
633 (PS 3) CULTURALLY INFORMATIVE PLANT IDENTIFICATION LABELS TO ASSIST VISITORS AND STUDENTS IN PUBLIC GARDENS
Authors: Needham Douglas C
Published: April 2024

The Oklahoma Botanical Garden and Arboretum (OBGA) at Oklahoma State University was awarded an “America the Beautiful” grant from the Oklahoma Department of Agriculture and the Oklahoma Urban and Community Forestry Council to develop a plant database and plant identification labels.

Culturally informative plant identification labels are engraved by a computer-controlled Newing-Hall 300 Engraver. Labels include not only scientific, common, and family names, but also cultural icons, depicting light, water, and pH preferences. The cultural icons provide visual cues to students in OSU's plant identification courses, as well as to visitors in OBGA's gardens and conservatories.

Additionally, the labels feature the common name engraved in Braille at the bottom of the label to facilitate education of visually impaired students and visitors. In anticipation of streamlining data collection on a plant's growth, flowering, fruiting, etc., each label also includes a barcode representation of the plant's accession number.
STIMULATING BUD BREAK AND IMPROVING OVER WINTER SURVIVAL IN ROOTED SOFTWOOD CUTTINGS
Authors: Perkins Anna , Bassuk Nina
Published: April 2024

The objectives of this research were to stimulate and accelerate new growth in rooted cuttings of difficult-to-root woody plants, thereby increasing overwinter survival rates in the first propagation year. Etiolated and non-etiolated cuttings were taken from field grown stock plants of Acer rubrum `October Glory', Hamamelis vemalis, Hamamelis virginiana, and Stewartia pseudocamellia. After a 4 week etiolation period, during which the bases of new shoots were covered in black velcro bands, cuttings were taken in June, 1992 and dipped in one of three levels of IBA: 500, 1,000, 5,000 ppm for A. rubrum `October Glory', A. rubrum `Red Sunset', and H. vernalis, and 1,000, 5,000 and 10,000 ppm for H. virginiana and S. pseudocamellia. After 3 to 8 weeks under mist, successfully rooted plants were given 16 hour days with 70/60 F. D/N greenhouse temperatures. Plants were treated with a foliar spray of thidiazuron 50 mg/L, thidiazuron followed by GA 4/7 250 mg/L ten days later, silver thiosulfite (STS) 1%, or STS followed by GA4/7 ten days later. Both STS and thidiazuron stimulated bud break in plants. After 4 weeks, plants were assessed for bud break, after which dormancy was induced under short days and cool temperatures (50/40 F. D/N). Once dormant, the plants' total growth and total nonstructural carbohydrates were measured, and plants were stored in 38 F. coolers for 3 months. At the end of 3 months, the plants were assessed for overwinter survival.
642 (PS 4) PLANT REGENERATION OF TWO ECHINACEA SPECIES FROM LEAVES
Authors: MacDermott Jomo , Bell L.M. , Trigiano R.N.
Published: April 2024

The North American prairie genus Echinacea (Asteraceae) contains approximately nine species with medicinal, insecticidal and/or horticultural value or potential. Echinacea tennesseensis, a narrow-leaf prairie relic found only in middle Tennessee was among the first plants listed as endangered; E. purpurea is a common garden coneflower. This research focused on developing tissue culture techniques to generate propagules of both plants from leaves. Shoots were induced to form from 1 cm2 leaf segments cultured for two weeks on MS medium supplemented with BA and IAA followed by three weeks of culture on MS medium without growth regulators. Nearly all (98%) of the shoots of E. purpurea rooted within three weeks in one-half strength MS salts medium without growth regulators and were easily acclimatized to greenhouse growing conditions. Shoots of E. tennesseensis rooted in MS medium amended with NAA or directly in soil with talc or alcohol-based NAA dips. However, only about 30% of the shoots could be rooted and acclimatized to field conditions.
REGENERATION OF HYPOCOTYL EXPLANTS OF GARDENEGGS (SOLANUM GILO)
Authors: Blay Essie T. , Porobo-Dessai Anant , Prakash C.S.
Published: April 2024

The success of crop transformation is contingent upon the efficient regeneration of cocultivated explants. This study was initiated as part of a transformation program designed to solve some critical problems in gardenegg, an important solanaceous fruiting vegetable in many tropical African countries. A preliminary investigation involving the screening of cotyledons, hypocotyl, and leaf explants on zeatin-, kinetin-, or BAP-supplemented media produced regeneration in all explant types, but hypocotyl explants were consistently faster and produced more plantlets/explants. In this study, hypocotyl explants excised from 2-week-old seedlings cultured on media composed of MS salts supplemented with 2% sucrose, 0.9 mg/1 thiamine,HCl, 2 mg/1 glycine, 1-4 mg/1 zeatin, zeatin riboside, or BAP, and 3.5% phtyagel. Zeatin and zeatin riboside induced the fastest and most prolific shoot intiation. Rhizogenesis, however, was better on BAP-supplemented media. All plantlets rooted readily when transferred onto a hormone-free medium. As many as 28 plantlets/explants were obtained in some treatments. Rooted explants transferred into potted soil mix and acclimatized for 2 weeks in a growth chamber grew normally.
655 (PS 4) IN VITRO ROOTING AND ACCLIMATIZATION OF PRUNUS SEROTINA USING PACLOBUTRAZOL
Authors: Eliasson Marybeth K. , Beyl Caula A.
Published: April 2024

Paclobutrazol (PBZ), a triazole growth retardant known to harden various species to stress, was incorporated into the in vitro rooting medium of Prunus serotina var. virens at rates of 0.00, 0.15, 0.30, and 0.60 mg/L with and without 1.0 mg/L indolebutyric acid (IBA). PBZ significantly reduced shoot growth in vitro but increased/improved the quality and coloration. Although not significant, the roots appeared shorter, thicker, more numerous, and percentage was higher. The percent water loss from detached leaves of in vitro plantlets was significantly reduced by PBZ and IBA, Four weeks after transfer to the greenhouse, survival was significantly improved by PBZ, IBA, and the combination. The incorporation of PBZ in vitro better enables plantlets of Prunus serotina var. virens to withstand the stresses associated with acclimatization and offers the potential to benefit other more difficult-to-acclimatize plant species.
ADVENTITIOUS SHOOT FORMATION IN EASTERN REDBUD (CERCIS CANADENSIS)
Authors: Distabanjong Karsedis , Geneve Robert L.
Published: April 2024

Adventitious shoot induction was studied using isolated parts of in vitro grown seedlings of Eastern redbud. The explants studied included the cotyledon node (with or without cotyledons), cotyledon, hypocotyl, epicotyl, root, nodal stem and seedling leaf pieces. Explants were treated with a factorial combination of benzylaminopurine (BAP) and thidiazuron (TDZ) on DKW medium. Cultures of Eastern redbud produced a low frequency of adventitious shoot formation for all explants tested except for explants with the cotyledonary node. These explants produced 5.9 shoots per culture after treatment with 10μM BAP + 1μM TDZ. However, shoots produced on a medium containing TDZ failed to elongate. Many of the TDZ induced shoots were abnormal and distorted. Shoot elongation was promoted by transferring explants to a medium with BAP alone.
668 (PS 5) EFFECT OF DIKEGULAC ON BRACT SIZE OF BOUGAINVILLEA
Authors: Norcini Jeffrey G. , Aldrich James H.
Published: April 2024

Flowering of Bougainvillea is enhanced when liners are treated 0 and 4 weeks after transplanting and pruning with 1200 or 1600 ppm dikegulac (ATRIMMEC). Dikegulac, however, slightly to moderately reduces bract size. This study was conducted to quantify the effect of dikegulac on bract size. Rooted liners of Bougainvillea `Mauna Kea' were transplanted into 2.5-liter containers (1 liner/container) on 14 April (Expt. 1) or 20 August 1991 (Expt. 2) and pruned (0 weeks). Dikegulac at 0, 400, 800, 1200, or 1600 ppm was applied at 0 and 4 weeks. Control plants were also pruned at 4 weeks. Plants were grown under full sun. In Expt. 1, 400 ppm dikegulac reduced bract size about 25%, with 800 to 1600 ppm reducing bract size about 37%. However, dikegulac had little to no effect on bract size in Expt. 2 seemingly due to cool temperatures. The mean minimum and maximum temperatures were about the same during the first six weeks of both experiments; however, the mean minimum/maximum temperatures for the remainder of Expt. 1 and 2 were 19.2°/30.4° and 10.8°/23.2°C, respectively.
669 (PS 5) RESPONSES OF ORNAMENTAL FLOWERING CABBAGE AND KALE CULTIVARS TO FOUR COMMERCIAL GROWTH RETARDANTS
Authors: Carter Johnny , Mahotiere Sauveur
Published: April 2024

Four commercial growth retardants (B-nine, Cycocel, A-rest and Bonzi) were compared for their effectiveness in controlling the growth and development of three ornamental flowering cabbage cultivars (white, red, and pink) and two flowering ornamental kale cultivars (frizzy red and red peacock). Two weeks after transplanting; seedlings of each cultivar were sprayed with aqueous solutions of the four commercial growth retardants. Treatments for each cultivar were arranged in a randomized complete block design with 6 replications. Plant height, plant width and dry weight were the parameters used to measure growth and development. Treatments for each cultivar were rated for head formation and color development. Results showed that all the growth retardants except for cycocel significantly affected growth and development without any effect on head formation and color development. Bonzi caused the greatest growth suppression.
EFFECTS OF SURESTEM PLANT GROWTH MODIFIER ON STEM NUMBER, LENGTH, AND QUALITY OF HYBRID TEA ROSES GROWN IN GREENHOUSES
Authors: Kust Cyril A.
Published: April 2024

SURESTEM plant growth modifier, applied in foliar sprays at 80.0 g ai/H to regrowing stems following rose stem harvest, increased Royalty variety hybrid tea rose stem number and length and improved stem quality. Stem numbers per harvest were increased in Samantha and Kardinal variety roses, but there were no changes in stem quality or stem length. For rose stems harvested on a growth cycle basis, excellent stem number increases were obtained when SURESTEM was applied about 7 days after 90% of the stems had been harvested. The best time of application was affected by temperature and light conditions in the greenhouse, by natural photoperiod in the absence of artificial lighting, and by stem harvest practices of the growers. The best time of application for plants managed on a continuous stem harvest system has not yet been determined. Commercial producers of long-stem roses are evaluating SURESTEM under an EPA Experimental Use Permit issued April 7, 1992. The EUP program and label also permits the evaluation of SURESTEM on other ornamental crops grown for cut stem production in greenhouses.
EFFECT OF GROWTH REGULATORS ON HEIGHT OF PENTAS
Authors: Wilfret G. J. , Harbaugh B. K.
Published: April 2024

Pentas (P. lanceolata Benth.) cv. Ruby Glow Red single node cuttings were grown in 15 cm pots in a glasshouse and developing laterals were pinched to one node. Plants were sprayed with chlormequat (CCC) at 0, 500, 1000, 1500, or 2000 ppm on 5, 10, or 15 days after pinching. An ancymidol (0.5 mg ai/15 cm pot) drench treatment was applied at the above 3 dates. Application date had no effect on plant height and ancymidol had minimal effect. All CCC treated plants were shorter than controls but little differences were recorded among CCC conc. Since most stem elongation occurred after the inflorescence was ca. 2 cm diam., a second experiment with similarly grown plants consisted of CCC sprays of 0, 500, 1000, 2000, or 4000 ppm applied 10 days after pinching. Additional CCC applications were made when the inflorescence was 2 cm diam. All treatments yielded plants shorter than controls which were 57 cm. Plants sprayed initially with CCC at 2000 ppm plus CCC at either 500, 1000, or 2000 ppm at the bud stage ranged from 28 to 32 cm tall, an ideal height range for 15 cm pots. CCC at 4000 ppm appeared to reduce stem turgidity and the inflorescence tended to droop at maturity.
HYBRID LILY RESPONSES TO DAY/NIGHT TEMPERATURE REGIMES (DIF), GROWTH RETARDANTS, AND GROWING MEDIA COMPOSITION.
Authors: Wulster George J. , Tonkin Don
Published: April 2024

Hybrid lilies(4 oriental & 2 asiatic) species were grown in commercial potting media formulations containing various percentages of composted bark. Lilies were grown in greenhouse sections maintained at either 21C day temperature and 15C night temperature or 15C day temperature and 21 C night temperature from emergence until anthesis. The growth retardants Paclobutrazol (Bonzl) and Uniconazole (Sumagic) were applied as a media drench at 0.25 mg a.i. per pot. Final height, days to flower from planting, days to flower from visible bud, and flower number were recorded for each treatment. Plant height was significantly reduced by potting media formulation, growth retardant treatment, and temperature regime. The effects of these treatments on bud number, and days to flower will also be discussed.
STAGE OF DEVELOPMENT AFFECTS NUTRIENT UPTAKE IN FOUR SNAPDRAGON CULTIVARS
Authors: Hood Teresa M. , Mills Harry A. , Thomas Paul A.
Published: April 2024

Nutrient uptake by Antirrhinum majus L. `Apache', `Jersey City', `Peoria', and `Philadelphia' was compared at three developmental stages: Stage I, vegetative to bud initiation; Stage II, bud initiation to visible bud; and Stage III, visible bud to anthesis. Significant differences in uptake occurred between one or more developmental stages for all nutrients tested (NO3-, NH4+, B, Ca++, Cu++, Fe++, K+, Mg++, Mn++, Mo-, P, and Zn++), Uptake of the majority of nutrients increased or remained high during Stage III. These results indicate that the current cultural practice of stopping fertilization at bud elongation should be reexamined. Differences in uptake between cultivars were found only for NO3- as uptake by 'Apache' was significantly higher than uptake by 'Philadelphia'.
691 (PS 5) INHERITANCE OF QUALITATIVE TRAITS IN NEW GUINEA IMPATIENS
Authors: Quené Robert-Jan W. , Strefeler Mark S.
Published: April 2024

New Guinea impatiens have been growing in popularity as a potted, bedding and hanging basket plant. This growth has been due mainly to the development of new cultivars by commercial breeding programs. However, no one has investigated or reported the inheritance of simple Mendelian traits of economic importance.

A study of the genetics of six qualitative traits was undertaken to elucidate inheritance of these traits in New Guinea impatiens. The traits studied were flower color, flower size, leaf color, leaf vein color, leaf variegation and variegation of leaf margins. Thirteen genotypes were used as parents in reciprocal crosses of all possible combinations. Fourteen crosses yield sufficient seed for use in the inheritance studies. Fifty to one hundred progeny were used from each cross. Segregation of the traits of interest were observed in the F1 populations. Inheritance measures were based on the segregation pattern of the F1 progeny.

Heritabilities for traits varied widely. Genetic models based on segregation ratios will be presented for each trait. The mode of inheritance and heritabilities revealed from this study will be useful to plant breeders in developing efficient cultivar improvement strategies.
692 (PS 5) CHARACTERIZATION OF GENES FROM MORNING GLORY (IPOMOEA [PHARBITIS] NIL) WITH HOMOLOGY TO A MAIZE PROTEIN KINASE
Authors: Bassett Carole L. , Rajeevan Mangalathau S.
Published: April 2024

Signal transduction plays a crucial role in an organism's response to its environment. Developmental processes like flowering in photoperiodically sensitive plants must employ some form of signal communication to effect this response. Protein kinases occupy an intermediate position in signal transduction pathways between signal perception and the final metabolic effect produced. Their importance is underscored by the fact that genes encoding protein kinases have been highly conserved during evolution. Over 30 independent clones were obtained by screening a genomic bank from morning glory DNA with a probe derived from a gene encoding a maize protein kinase. Selected clones were digested with SacI and the resulting DNA fragments transferred to filters for hybridization with the maize probe. The results indicate that these genes represent a small family comprised of approximately 5 members based on the hybridization conditions employed for their isolation.
697 (PS 5) MICRONUTRIENT TOXICITY SYMPTOMS IN BUFFALOGRASS
Authors: Schumacher Matthew A. , Jackson Marcus B. , Duysen Murray E. , Smith Ronald C. , Lee Chiwon W.
Published: April 2024

The effect of increasing micronutrient levels on buffalograss (Buchloe dactyloides) was investigated. Seedling plants established in peat-lite mix in 10-cm pots were irrigated with solutions containing 0.5, 1, 2, 4, 6, 8, or 12 mM of boron (B), chloride (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), or zinc (Zn). The control solution contained (in μM): 20 B, 0.5 Cu, 40 Fe, 10 Mn, 0.5 Mo and 4 Zn. A standard macronutrient concentration was used for all treatment solutions. Boron and Mo induced visual toxicity symptoms more readily than other micronutrients. Boron toxicity was characterized by chlorosis often accompanied by bleached leaf tips, while Mo toxicity resulted in leaf necrosis. The lowest levels that induced foliar toxicity symptoms were: 0.5 mM B, 2 mM Cu, 4 mM Fe, 6 mM Mn, 1 mM Mo, and 4 mM Zn. Chloride did not induce foliar abnormalities in the concentration range tested. Biomass yield was reduced when the nutrient solution contained 2 mM B, 8 mM Cu, 2 mM Mo, or 12 mM Zn. Elevated levels of Cl, Fe and Mn did not alter dry matter yield. Tissue concentrations of micronutrients were also determined.
707 (PS 6) CAULIFLOWER YIELD AND TIPBURN INCIDENCE; EFFECT OF A HYGROSCOPIC SOIL AMENDMENT AND IRRIGATION IN SANDY SOILS
Authors: Kossowski Jan M. , Wilcox Dartene
Published: April 2024

Cauliflower grown in hot and dry summer conditions is susceptible to a Ca and water-related physiological disorder known as tipburn. The objective of this research was to investigate the effect of several cultural practices influencing plant water relations on cauliflower yield, stomatal conductance and tipburn occurrence. `Snow Crown' seed was sown in field seedbeds on 21 Apr 1992 and seedlings transplanted to the production field on 10 June 1992. The experimental design was a split-plot with 4 replications. Main factor treatments were: a hygroscopic polymer, AquaMend, applied at 33.6 kg/ha in bands and rototilled before transplanting, night misting of plants beginning at head formation, and night covering of plants with a plastic tent, and a non-treated control. Plants in sub-plots were irrigated to field capacity when soil matric potential (SMP) reached a minima of -20, -50, or -80 kPa. Occurrence and severity of tipburn was rated as well as stomatal conductance. Marketable yields without wrapper leaves were measured on 2 harvest dates. Neither tipburn nor stomatal conductance were significantly effected by treatment although stomatal conductance showed a tendency to increase with decreasing SMP values Decreasing SMP also significantly increased yields, which is consistent with the simultaneous increase in stomatal conductance, and probably associated with the excessive rainfall and frequent flooding in 1992. The use of Aquamend significantly increased yield and head weight as SMP decrease. Among the cultural practices. Aquamend produced the greatest and tents the lowest yields. The use of Aquamend shows potential for increasing yields and decreasing irrigation requirements in cauliflower production in sandy soils.
INFLUENCE OF WINTER COVER CROPS AND NITROGEN FERTILIZER ON TOMATO AND BEAN PRODUCTION AND SOIL NITRATE DISTRIBUTION
Authors: Hatt Heather. A. , Brock Kathy H. , Decoteau Dennis R. , Hoyt Greg D.
Published: April 2024

Winter cover crops (wheat and crimson clover) in combination with three levels of nitrogen fertilizer (0, 6, 120 kg/ha) were evaluated as to their influence on bean and tomato production (fruit yield, disease and insect on fruit, and nutrient content of fruit and plants). The influence of cover crop and fertilizer on nitrogen distribution in the soil profile was determined for each treatment. A split plot design was used with the cover crop as the main treatment and nitrogen rate as the split treatment. Soil cores were taken in the spring before planting and at the termination of harvest each year. Results indicate that cover crop had an effect on non-marketable bean fruit, but did not affect marketable fruit harvested for both bean and tomato. Cracked and insect damaged tomato fruit was greatest in fallow and wheat treatment, and culls of bean fruit was greatest in the clover treatment. Cover crop treatment had no affect on overall tomato and bean plant nutrient content. Wheat and clover cover crop treatment reduced the amount of nitrate leaching in the soil profile as compared to the fallow. These results suggest that wheat and clover can be used effectively as cover crops to reduce nitrate leaching without affecting bean and tomato fruit yield.
EVALUATION OF HARVEST SCENARIOS FOR COWPEA (Vigna unguiculata L. Walp), A CANDIDATE SPECIES FOR CONTROLLED ECOLOGICAL LIFE-SUPPORT SYSTEMS
Authors: Ohler Tracy A. , Mitchell Cary A.
Published: April 2024

Physiological characteristics of cowpea suggest it as a candidate species for CELSS. Improving productivity will be essential for CELSS. The leaves of cowpea provide an added source of edible biomass and may extend harvest index (HI=edible/total biomass). A greenhouse study evaluated the interaction of photoperiod and cultivar with 3 harvest scenarios: 1) seed only, 2) seed and leaves (mixed), and 3) leaves only. Overall, seed-only HI was 25% less than leaf-only HI. For IT84S-2246, a short-day cultivar for flowering, both mixed and seed only HI dropped 20% as photoperiod increased from 8 to 24 hours. While edible yield rate remained constant, shoot dry weight increased as photoperiod increased for both harvest scenarios, thus decreasing HI. For the same reason, the leaf-only HI of S-2246 increased as photoperiod increased. For IT82D-889, a day-neutral cultivar for flowering, HI remained constant regardless of photoperiod. Leaf-only HI was 65%, whereas seed and mixed HIs were 40 and 45% respectively. For all harvest scenarios, D-889 produced 25 grams less edible biomass per plant than that of S-2246. Due to the interaction of harvest scenario and cultivar, cultivar selection must be based on yield performance in each type of harvest scenario. Further investigations will answer the extent of sacrificing seed yield for leaf harvest. NASA Grant NAGW-2329.
TILLAGE, COVER, AND ALLELOPATHIC EFFECTS ON BROCCOLI.
Authors: Kelley W.T. , Coffey D.L.
Published: April 2024

`Packman' hybrid broccoli was grown under three tillage systems at three locations in 1989 and 1990 to study the feasibility of no-till production. Tillage systems consisted of 1) conventional tillage with no winter cover, 2) conventional tillage with wheat winter cover, and 3) no-till transplanted directly into paraquat-killed wheat cover. Locations were at Knoxville, Greeneville and Crossville, TN. Yield, value and marketability of broccoli were significantly reduced in no-till vs conventional tillage. The possibility that small grain cover crops have a deleterious effect on broccoli growth was then investigated. Broccoli was grown in greenhouse pots with solutions of ferulic, syringic, p-coumaric, p-hydroxybenzoic and vanillic acids at 1, 10, 100 and 1000 μM concentrations and compared to controls which received only water. Shoot dry weight and plant height were both reduced with increasing acid concentrations. Soil samples were taken from field plots in 1990 and analyzed for levels of these acids using HPLC. Soils with higher levels of mulch had higher levels of ferulic and p-coumaric acid, but similar levels of the other acids. Allelopathic effects of the cover crop is a potential cause of reduced broccoli yields under no-till conditions.
INFLUENCE OF NITROGEN AND PLANT SPACING ON SPORT PEPPERS
Authors: Motsenbocker Carl E. , Mulkey William A. , Boudreaux James E. , Buckley J. Blair
Published: April 2024

Field studies were conducted in 1992 with `GMississippi Sport' pepper. Plants were established by direct seeding at 8 cm or transplanting at 8, 15, 23 and 30 cm in-row plant spacing. All in-row plant spacings received one of five nitrogen applications (0, 55, 110, 165, 220 kg pe hectare). Plant parameters, fruit quality and yield were monitored. A modified commercial snap-bean harvester was evaluated for harvest. Closer plant spacings resulted in greater red and combined red and green grade yields. Nitrogen rate did not influence yield or stem diameter and height. The use of the modified mechanical snap-bean harvester appears to be a feasible technique to harvest sport pepper.
SIMULATION OF HOURLY TEMPERATURES AND ESTIMATION OF CHILL UNITS.
Authors: Rojas-Martinez Raymundo , Seeley Schuyler D. , Jensen Donald
Published: April 2024

A model [HeatSine-Exponential (HSE)] for the course of diurnal temperatures was validated with forty-three years of hourly temperatures from the Salt Lake City (Utah) airport. Daily parameters of the HSE model were determined by non-linear regression analysis. The HSE was compared to linear and other sine-exponential formulations. The HSE model had the highest average coefficient of determination (r2 = 0.89) and the lowest average root mean square error (0.92C). All the models under study were tested for the estimation of chill units and compared against chill accumulations computed directly from hourly temperatures. The HSE and sine-exponential models were simplified through systematic variation of the model parameters. Deviations from the hourly temperature results were analyzed using relative error (RE). The average RE for the HSE model was 3.3% [standard deviation (s) = 3.0]. The best linear method estimated chill units with an average RE of 6.1% (s = 4.3).
AMMONIA AND/OR ITS METABOLITES INFLUENCE FLOWERING, FRUIT SET, AND YIELD OF THE `WASHINGTON' NAVEL ORANGE
Authors: Ali Anwar G. , Zheng Yusheng , Sagee Oded , Protacio Calixto , Lovatt Carol J.
Published: April 2024

A cause and effect relationship between tree ammonia status and floral intensity was established for Citrus sinensis L. cv. Washington navel orange. Artificially raising tree ammonia content by foliar application of low-biuret urea during or at the end of a minimal stress treatment increased leaf ammonia content and both the number of floral shoots and flowers per shoot, but did not increase vegetative shoot production. Apical flowers initiated in response to stress exhibited maximum tissue concentrations of ammonia and putrescine and activity of the de novo arginine biosynthetic pathway one week after the end of the stress treatment. All three criteria decreased in parallel as flowers developed through petal fall. Foliar-applications of low-biuret urea during early bloom increased ovary putrescine content and fruit set. Winter foliar applications of low-biuret urea to commercially-producing, nitrogen-sufficient `Washington' navel orange trees just prior to or during flower initiation increased yield by approximately one packing carton (17 kg) per tree in three successive years without a reduction in fruit size. Winter application of low-biuret urea was cost effective.
FLOWERING PEAK MODELS OF MACADAMIA (MACADAMIA INTEGRIFOLIA)
Authors: Hwang San-Gwang , Kobayashi Kent D. , Nagao Mike A.
Published: April 2024

Statistical models were developed to predict the days from the starting date of the flowering season to the first peak of flowering of macadamia. The macadamia (Macadamia integrifolia Maiden and Betche) cultivar Ikaika was studied at two locations on the island of Hawaii. At location 1, TGDD and TSOLAR were the factors included in the model, where TGDD is the total growing degree days accumulated during the 18 weeks after the ending date to the next starting date of the flowering season. TSOLAR is the total solar radiation accumulated during the 18 weeks after the ending date to the next starting date of the flowering season. The model predicted the first flowering peak one day before it occurred in the field. At location 2, MINT and TGDD were the factors included in the model, where MINT is the average daily minimum temperature during the 18 weeks after the ending date to the next starting date of the flowering season. The model predicted the first flowering peak on the day it occurred in the field. These models could be used to help predict the first flowering peak so that bees could be brought in to increase cross-pollination and subsequent yields.
USING MECHANICAL PRUNING TO MITIGATE ALTERNATE BEARING OF PISTACHIOS
Authors: Ferguson Louise , Beede Robert
Published: April 2024

A single severe mechanical pruning done January, 1985, with the following treatments, hand pruned control, hedging, topping and topping and hedging, successfully reduced the alternate bearing of pistachios. The respective alternate bearing indexes are as follows; control, 0.88; hedged, 0.79, topped. 0.55, hedged and topped, 0.36. All treatments produced approximately equal cumulative yield over the 7 year experimental period. However, the most severely pruned trees demonstrated yield loss in the first 2 years after pruning.

The severe mechanical pruning, done prior to the low crop year, produced its effects by forcing trees to produce less fruiting wood during the off-crop year. The effects of a single severe mechanical pruning persisted 7 years.
BACTERIAL WILT-TOLERANT SOMACLONES OF TOMATO (LYCOPERSICON ESCULENTUM Mill.).
Authors: Bobisud Carol A. , Martin Susan P. , Sekioka Terry T.
Published: April 2024

Somaclones of tomato cultivar `Healani' were tested in a bacterial wilt infected field. Eighteen lines were found to be tolerant of bacterial wilt. Field testing of `Healani' and the bacterial wilt tolerant somaclonal lines showed character differences in some of the lines. Significantly lower yield than `Healani' was found for all somaclonal lines. Diameter of the fruit was significantly smaller in seven of the lines, while pericarp thickness was significantly less in seventeen of the lines. In seven of the lines, fruit locule number was significantly greater than `Healani' fruits. Generally, the occurrence of radial cracks and concentric cracks appeared to be greater in the somaclonal lines.
NON-DESTRUCTIVE SCREENING FOR RESISTANCE TO MULTIPLE DISEASES USING EXCISED PLANT PARTS IN PEPPER (CAPSICUM SPECIES)
Authors: Pae Do-Ham , Yoon Jin-Young , Lee Jung-Myung
Published: April 2024

A non-destructive screening system for resistance to multiple diseases was devised by utilization of excised plant parts such as leaf, shoot and fruit, which would allow evaluation of the same tested plants for reaction to major diseases and for other horticultural traits as well. A simple device made it possible to maintain freshness of the excised leaves and shoots long enough for the symptoms to develop fully. By inoculating suspension of bacterial leaf spot disease to the leaves excised, three genetic reactions, i.e, vertical resistance, horizontal resistance and susceptibility, were discerned as successfully as when inoculated on the intact leaves. `CM331' and `PI201234', of which resistance to Phytophthora blight had been shown in conventional screening by drenching at the seedling stage, also revealed the resistance when the inoculation was directly given to the excised shoot. Inoculation of anthracnose by high pressure spray resulted in more distinct differences between genotypes and less variation within genotypes than the conventional method by pins. Local lesions were observed in 6 days after inoculation of TMV on both excised and those kept intact on the plant in the resistant varieties. It was confirmed that excision of the plant parts for the disease screening by the new method gives little influence on the growth and yield of the plants being tested.
FRUIT FIRMNESS OF PARTHENOCARPIC VERSUS NONPARTHENOCARPIC PICKLING CUCUMBER CULTIVARS.
Authors: Cook Kevin L. , Gabert August C. , Baggett James R.
Published: April 2024

Parthenocarpic pickling cucumbers may be advantageous to conventional nonparthenocarpic cultivars due to their higher fruiting capacity and ability to produce fruit under poor pollination conditions. The processing quality, particularly firmness, of parthenocarpic pickling cucumbers has been questionable. Fruit firmness of six parthenocarpic and six nonparthenocarpic cultivars was evaluated in 1992 at Brooks, Oregon. Plots covered with floating row covers, to prevent pollination and ensure parthenocarpic fruit set, were compared with noncovered plots. Parthenocarpic cultivars were significantly softer than nonparthenocarpic cultivars. Cultivars within the parthenocarpic and nonparthenocarpic types were significantly different from one another. Fruit produced under row covers were significantly firmer than those which were pollinated. Cultivars which were firmer under the row cover tended to be firmer in the absence of row cover. Floating row covers allow firmness and parthenocarpic fruiting ability to be evaluated concurrently.
ANATOMY OF BLIND NODES IN PEACH
Authors: Boonprakob Unaroj , Byrne David H. , Rouse Robert E. , Mueller Dale M.J.
Published: April 2024

Blind nodes in peach is widely observed in the mid summer growth in the southern of the U.S.A. This condition is characterized by the apparent absence of axillary buds. The developmental anatomy of blind nodes was investigated by sampling peach shoots every two weeks throughout the season. Although the bud initiation was observed in both blind and normal nodes, the differentiation in the blind nodes was limited such that no prophyll development was observed. Furthermore, it appeared that the initiated meristems in the blind nodes may have degenerated to form blank leaf axils.
HEXAZINONE MOVEMENT IN BLUEBERRY SOILS IN MAINE
Authors: Yarborough David E. , Jensen Klaus I.N.
Published: April 2024

An experiment was established to compare open mineral soil, soil with bark mulch, soil with blueberry cover and tilled clones on hexazinone movement through the soil. Hexazinone was applied preemergence to a lowbush blueberry field at 2 kg/ha in the spring of 1990 and soil samples were taken at the time of application, one month, six months and one year after application at a depth of 0-5 cm, 5-15 cm and 15-25 cm. At the time of initial application, the mulched plots had twice the amount of hexazinone as the others. The hexazinone concentration after one month shows the concentration of hexazinone decreased with an increase in depth, with the open areas having the highest levels of hexazinone. It appears that the hexazinone has moved down through the soil column with the higher concentrations above and lower concentrations below. The data indicate that the hexazinone decreased rapidly in the first month, and then declined by about half over each 6 months thereafter. It appears that there is less hexazinone in the lower layers of the soil and that the open areas had the highest concentration at one month but the levels equal out over time.
STRAWBERRY REGROWTH AFFECTED BY CROWN SIZE FOLLOWING EXPOSURE TO SUB-LETHAL FREEZING
Authors: Warmund Michele R.
Published: April 2024

The effect of crown diameter on the regrowth of `Earliglow' and `Honeoye' strawberry (Fragaria × ananassa Duch.) plants was evaluated following exposure to sub-freezing temperatures. Large-diameter (12-14 mm) crowns of both cultivars had greater leaf number and dry weight than medium (9-11 mm) and small (6-8 mm) diameter crowns when plants were grown in the greenhouse after the freezing test. Large diameter crowns of both cultivars and medium-diameter crowns of `Honeoye' plants produced greater root dry weight than those of small-diameter crowns. The number of days to bloom of the primary flower increased with exposure to lower temperatures only in the large-diameter crowns of `Earliglow'. However, in small-diameter crowns of `Honeoye', the time of bloom decreased with exposure to lower temperatures. The fruit weight of small- and large-diameter crowns of `Earliglow' plants decreased linearly with exposure to lower temperatures. `Honeoye' plants subjected to -7C and unfrozen control plants had similar fruit weight.
INFLUENCE OF MYCORRHIZA ON GROWTH OF STRAWBERRY SEEDLINGS
Authors: deSilva Amal P. , Patterson W. Keith
Published: April 2024

A green house experiment was conducted to study growth response of strawberry seedlings inoculation to mycorrhizal fungi. Seeds of strawberry cultivar `sweetheart' were planted in trays of 25cm × 25cm × 5cm which were inoculated with Glomus intraradices. Spore densities of 0, 750, 1500, 3000, 7500, 12000 per plant were used. Results indicated that total dry wts. of plants inoculated with highest spore density significantly differed from the other treatments as well as from the controls. Moreover, total dry wts. of all treatments significantly differed from controls. The highest infection (71%) was seen at the 12000 spore density. Plant heights were variable at first two measurement dates. However, at the 3rd date, the 12000 spore density treatment significantly increased over all treatments except the 3000 level.
EFFECTS OF NITROGEN FORM ON VEGETATIVE GROWTH, PHOTOSYNTHESIS, AND EFFLUENT PH IN `CLIMAX' AND `SHARPBLUE' BLUEBERRIES
Authors: Merhaut Donald J. , Darnell Rebecca L.
Published: April 2024

Effects of N form (NH4 vs. NO3) on growth, photosynthesis, chlorophyll concentration, and pH were evaluated in `Climax' and `Sharpblue' blueberries. Plants were fertilized every other day with a modified Hoagland's solution containing 5 mmoles N as (NH4)2SO4 or NaNO. Change in solution pH as it percolated through the sand was measured. Effluent pH decreased to 3.0 for NH treatments and increased to 5.7 for NO3, treatments. As effluent pH changed, solution pH was adjusted to 6.5 for NH4, treatments and decreased to 3.0 for NO3 treatments, to maintain a comparable pH gradient within the sand. Leaf dry weight and total stem length were greater in NH4 vs. NO3 fertilized plants for both cultivars. Leaf area was significantly greater in the NH4 vs. NO3 treatments of `Climax'. Nitrogen form did not affect stem or root dry weight in either cultivar. There were no differences in leaf photosynthetic rate or chlorophyll concentration between N treatments. Thus, increased growth in NH4 treatments was not attributed to N form effects on photosynthetic rates.
EARLY SHADING REDUCES FRUIT SET IN CRANBERRY
Authors: Roper T.R , Klueh J.S. , Hagidimitriou M.
Published: April 2024

Fruit set has been shown to be a major limitation of yield in cranberry (Vaccinium macrocarpon). Availability of resources has been implicated to limit fruit set. To determine when carbohydrate availability was most important to fruit set, we shaded 0.5 m2 sections of a cranberry bed with shade cloth providing either 72% or 93% shade at prebloom, postbloom or preharvest in 1991 and 1992. Plots were not shaded during bloom to not interfere with pollination. Preharvest shading was never different than controls. Severe prebloom shading reduced fruit set in 1991, but not 1992. Severe postbloom shading reduced fruit set in 1991 and severe or light postbloom shading reduced fruit set in 1992. Postbloom shading reduced berry size and yield per subplot both years. Fruit set was determined in 1992 for plots that were shaded in 1991. Fruit set in 1992 was not affected by 1991 shading treatments. At the conclusion of the shading treatments, nonstructural carbohydrate content of uprights was reduced by 40 to 50% compared to controls. Fruit set appears to be dependent on resources produced during the postbloom period. These data support the hypothesis that fruit set in cranberry is resource limited.
FLORAL INITIATION IN RUDBECKIA HIRTA UNDER LIMITED INDUCTIVE PHOTOPERIODIC TREATMENTS
Authors: Harkess Richard L. , Lyons Robert E.
Published: April 2024

Two experiments were conducted to examine the response of Rudbeckia hirta to limited inductive photoperiodic treatments. Plants of R. hirta were grown to maturity under short days (SD). In the first experiment, mature plants were placed under LD for 0, 8, 16, 24 or 32 LD before being returned to SD with one group remaining under LD as a control. In the second experiment, mature plants remained under LD for 0, 4, 8, 12, 16, 20, 24, or 28 days before they were returned to SD. Meristems were sampled 0, 4, 8, or 12 days after return to SD and histologically examined. Plants receiving 32, 36, 40 or 44 LD were used as a continuous LD control. As the number of inductive cycles was increased, plant height and branch number increased. Plants receiving only 4 LD never progressed beyond floral initiation. After 8 LD, the meristems continued to develop even when returned to SD. Once involucral bract primordia initiated, the meristem was committed to flower whether in LD or SD conditions. Plants receiving 24 or more LD reached anthesis earlier than plants receiving fewer LD.