bluuebunny/crossref_metadata_2025 huggingface dataset:
997 USE OF MOLECULAR MARKERS IN BREEDING FOR RESISTANCE TO FUNGAL PATHOGENS
Authors: Kell James D.
Published: February 2019

The use of RAPD markers in disease resistance breeding has been successfully demonstrated in horticultural crops. The identification of RAPD markers and their potential role in disease resistance breeding was first demonstrated in tomato; the procedure of bulk segregant analysis for detecting linkages between RAPD markers and genes conditioning resistance to downy mildew was described in lettuce; the use of linked RAPD markers to facilitate the efficient pyramiding of epistatic rust resistance genes to prolong their durability has been illustrated in common bean; the development of allele specific or sequence characterized primers linked to resistance genes has been achieved in pea, bean, tomato, and lettuce Indirect selection for disease resistance based on molecular markers is not a replacement for classical breeding procedures. Used as tools, markers offer breeders unique opportunities to combine resistance to an array of different pathogens and efficiently pyramid epistatic resistance genes for highly variable fungal pathogens. This would not always be possible in the absence of linked markers.
SEEDLING ROOT AND SHOOT COMPONENTS IN RELATION TO STAND ESTABLISHMENT
Authors: Leskovar Daniel I. , Stoffell Peter J.
Published: February 2019

Initiation, development, and subsequent growth of seedling root and shoot components can have a direct influence on the quality, adaptation, and survival of seedlings, particularly under stress conditions. Taproot, basal, lateral, and adventitious root components (common indicot plants) each have their own development sequence, growth rate, and may have separate functions for subsequent seedling growth and development. Stresses originating in root components may be expressed in shoots affecting dry matter partitioning between roots and shoots. Partitioning and development of root morphological components and root/shoot growth adaptation to stress environments will be presented for various vegetable species. Implications of root developmental differences in relation to field planting methods will be discussed. Understanding seedling morphology, physiology and assimilate partitioning during early ontogeny would assist directing strategies to improve field establishment and ultimately crop production.
1006 OVERVIEW OF GENE AVAILABILITY, IDENTIFICATION AND REGULATION
Authors: Owens Lowell D.
Published: February 2019

A growing number of horticulturally useful genes have been introduced into plants. Most are designed to impart resistance to pests, but others affect plant morphology, cold or drought tolerance, sucrose transport, starch synthesis, flower color or fruit ripening. Although most of the genes introduced were originally cloned from plants or plant viruses, some were cloned from bacteria or animals. Identification of gene function has generally involved characterization of the gene product prior to cloning the gene. Recent advances in genetic mapping, however, have opened new approaches to cloning genes prior to isolation of the gene product or to an understanding of the biology of the trait conferred. Most candidate genes for introduction need to be modified to achieve the intended purpose. Rational modification is now possible, to a considerable extent, based upon current knowledge of gene structure and regulation. Some guidlines for modification and examples thereof will be examined.
1009 PHENOTYPE MODIFICATION AND DISEASE RESISTANCE VIA REGULATED EXPRESSION OF THE CYTOKININ BIOSYNTHESIS GENE
Authors: Smigocki Ann C.
Published: February 2019

Cytokinins were first recognized as a class of phytohormones for their ability to promote cytokinesis in cultured plant cells and have since been shown to be involved in a wide range of physiological processes. Most recently, the availability of phytohorm one-specifying genes from Agrobacterium tumefaciens has allowed for direct in planta manipulation of cytokinin levels. Overexpression of the isopentenyl transferase (ipt) gene by constitutive promoters led to enhanced ability of plant cells to undergo shoot organogenesis but the high endogenous cytokinin levels almost completely suppressed root development. Transient overproduction of cytokinins using promoters regulated by environmental and/or developmental factors did not inhibit regeneration of rooted plants. Transgenic plants in which cytokinin levels can be modulated are being used to characterize the participation of cytokinins in fundamental regulatory mechanisms of morphogenesis, delayed senescence, disease resistance and directed nutrient transport. The potential for using reconstructed cytokinin biosynthesis genes in economically important crops is of tremendous agronomic significance.
1010 DELAYED PETAL SENESCENCE IN TRANSGENIC CARNATION USING ANTISENSE ACC OXIDASE
Authors: Savin Keith W. , Baudinette Stanley C. , Graham Michael W. , White Ellen L-J. , Michael Michael Z. , Bayly Ann , Lu Chin-Yi , Chandler Stephen F. , Cornish Edwina C.
Published: February 2019

Ethylene is essential for the senescence process in many fruit and flowers. In the last two steps in the biosynthesis of ethylene in plants ACC synthase converts S-adenosyl methionine to 1-aminocyclopropane-1-carboxylic acid(ACC). ACC oxidase (ACO) then degrades ACC to ethylene. Inhibitors of ethylene synthesis, such as amino-oxyacetic acid, and of the response to ethylene, such as silver thiosulphate, delay or prevent senescence. By expression of an antisense version of ACO RNA, we have generated two varieties of transgenic carnation which produce flowers with an extended vase life. These were produced using the cultivars Red Sim and White Sim. Flowers from these plants produce very little ethylene and normally fail to display the inrolling phenotype typical of senescence in this species. At the time after harvest when inrolling would normally lake place (5 days), the antisense ACO flowers produce only barely detectable levels of endogenous ACO mRNA or ACS (ACC Synthase) mRNA. Exposure to exogenous ethylene(100ppm) induces inrolling and production of ACS and ACO mRNA species. Such carnations will be valuable both as a commercial product and as a tool for further exploring the role of ethylene in carnation flower senescence and leaf wound response.
1020 ENVIRONMENTALLY SOUND APPLICATION OF NITROGEN TO OPTIMIZE YIELD AND FRUIT QUALITY IN APPLES
Authors: Fallahi Esmaeil , Simons Brenda R. , Fellman John K. , Colt W.M.
Published: February 2019

Influence of different quantity and timing of nitrogen application on various physiological aspects of `Redspur Delicious' apple, including nutritional partitioning, bud initiation, fruit set, yield, fruit quality and nitrate movement in the soil were studied over several growing seasons. Urea at the rates of: 40.2 Kg/ha; 160.8 Kg/ha; 281.3 g/ha; 401.9 Kg/ha; 522.4 K /ha were applied. Each rate of urea was applied: all at full bloom; half at full bloom and half at late spring; or all in fall. In 1993, time of application did not influence yield, fruit weight, color or soluble solids at harvest. Trees that received 401.9 and with 522.4 Kg/ha had higher yield than those with other quantities. Trees with 160.8 and 281.3 Kg/ha had higher yield than trees with 40.2 Kg/ha. Fruit weight in all quantities, except that of 522.4 Kg/ha, were similar. Fruit weight of trees with 522.4 K /ha was reduced. Fruit color was reduced as N quantities increased. Trees with 40.2 Kg/ha N had lower soluble solids than all other quantities. A high level of N increased ethylene and respiration in the fruit. Thus, if the poor color of fruit is due to high nitrogen, a long delay in harvest to improve the color could lead to an over ripe fruit. A preliminary test did not indicate harmful levels of nitrates movement in the soil.
1021 RECENT ADVANCES IN NATIONWIDE STUDIES OF CRANBERRY NITROGEN NUTRITION
Authors: Davenport J. R. , DeMoranville C. J.
Published: February 2019

Like many fruit crops, the difference between vegetative and reproductive production in cranberry is strongly influenced by nitrogen supply, as is fruit quality. However, the optimal supply for this crop has not been established. Further, there have been mixed results on whether or not cranberry can metabolize nitrate nitrogen. Within the past 6 years there has been an upsurgence in research on cranberry nitrogen nutrition and it has started to provide answers to some of these unknowns. Results from the lab of L. Peterson (U Wi - Madison) have shown that cranberry will take up nitrate nitrogen, however the uptake is minimal unless ammonium nitrogen is present. The work from Peterson's lab has also shown that there is some nitrate reductase activity in cranberry leaves, albeit at very low levels. Work that we have conducted and work by J. Hart's group (OSU) have been the basis for establishing optimal nitrogen rates and timings for cranberry in the different growing areas in North America. Overall, the work from these different groups has shown that except in extreme situations, 22 - 33 kg N/ha is optimal for cranberry production. However, timing of application varies widely due to weather conditions in the different growing areas.
1035 CONTAINER ORNAMENTAL PRODUCTION IN AN ARTIFICIAL POTTING MIX
Authors: Rauch Fred D. , Murakami Paul K.
Published: February 2019

Several trials have been conducted to determine the optimum amendment level for the production of container foliage plants in a 1:1, V:V, peat:perlite potting mix.

Experiments with various controlled-release fertilizers have shown superior growth and quality with resin coated products in an artificial mix. This appears to correspond to the nitrogen source with those containing nitrate and ammonium nitrogen giving better results than those with other nitrogen sources, such as IBDU or urea.

Trials with variable rates of dolomitic lime resulted in better or equal growth and quality of a variety of foliage plants without added lime even at pH levels of 4.0.

These results suggest the recommendations for the production of container plants in mixes without soil need to be reviewed and perhaps revised.
COURAGE TO CHANGE: LAND-GRANT COLLEGES OF AGRICULTURE
Authors: Zuiches James J.
Published: February 2019

The Board on Agriculture, National Research Council, has established a committee to (a) review the land-grant system of colleges of agriculture, (b) provide an evaluation and assessment of the strengths, opportunities, myths, and stereotypes; and (c) provide a vision for future development and innovation in organizational structures, functions, and processes. The committee has been charged to discuss these topics with stakeholders and constituencies, invite dialogue and contributions to reconceptualizing the system, and create a synthesis and recommendation. At the workshop, I will sketch out the scope of the study, data collection strategies, and initiate the process of dialogue and critique.
1050 COMPUTER AIDED COMMUNICATION FOR HORTICULTURISTS
Authors: Rhodus Tim
Published: February 2019

Effective communication of horticultural information over long distances requires the ability to present and receive not only text-based information but also images, sounds, and live-action video. Until recently, the Internet enabled users to communicate in each of these four modes, but not simultaneously. However, as a result of the World-Wide Web (WWW) project and the creation of NCSA Mosaic software, Internet users are able to access and deliver practically any form of communication, as long as it can be digitized. Information from around the world on literally thousands of subjects is now available 24 hours a day. Opportunities to communicate with the general public, primary and secondary science students, or practicing horticulturists are no longer limited by publication delays, travel distances, or media limitations.
1056 POTENTIAL OF PYRETHRUM PRODUCTION IN PACIFIC NORTHWEST
Authors: Bhat B.K. , Lemma G.Y.
Published: February 2019

Pyrethrins is one of the safest natural insecticides known to man that is least toxic to all warm blooded animals but highly-toxic to a wide range of insect species. The insecticide is extracted from the flowers of pyrethrum (Chrysanthemum cinerariaefolium Vis). United States of America consumes almost 85 per cent of the World production of pyrethrins imported from countries like Kenya, Tanzania, Australia and others. The paper discusses the potential of commercial pyrethrum production in the U.S.A., especially in the states of Washington, Oregon, and California.
Relative Humidity Influences Yield, Edible Biomass, and Linear Growth Rate of Sweetpotato
Authors: Mortley D.G. , Bonsi C.K. , Loretan P.A. , Hill W.A. , Morris C.E.
Published: February 2019

Growth chamber experiments were conducted to study the physiological and growth response of sweetpotato [Ipomoea batatas (L.) Lam.] to either 50% or 85 % relative humidity (RH). Vine cuttings of T1-155 were grown using the nutrient film technique in a randomized complete-block design with two replications. Temperature regimes of 28/22C were maintained during the light/dark periods with irradiance at canopy level of 600 μmol·m-2·s-1 and a 14/10-hour photoperiod. High RH (85%) increased the number of storage roots per plant and significantly increased storage root fresh and dry weight, but produced lower foliage fresh and dry weight than plants grown at 50% RH. Edible biomass index and linear growth rate (in grams per square meter per day) were significantly higher for plants grown at 85 % than at 50% RH. Leaf photosynthesis and stomatal conductance were higher for plants at 85 % than at 50% RH. Thus, the principal effect of high RH on sweetpotato growth was the production of higher storage root yield, edible biomass, growth rate, and increased photosynthetic and stomatal activity.
Ethylene Gas for Defoliation of Hydrangeas
Authors: Blom Theo J. , Smith Richard B.
Published: February 2019

Summer-grown Hydrangea macrophylla subsp. macrophylla var. macrophylla (Thunb.) were exposed for 1 week to CzH4 at 0,0.5,2.0,5.0,50, or 500 μl·liter-1 in dark storage at 16C for defoliation before cold storage. The number of leaves remaining per shoot for all cultivars decreased with C2H4 concentration, and >5 μl C2H4/liter was effective in defoliating `Kasteln', `Mathilda Gutges', and `Todi' but not `Merritt's Supreme'.
Characterization of New Sources of Resistance in Cowpea to the Southern Root-knot Nematode
Authors: Fery Richard L. , Dukes Philip D. , Thies Judy A.
Published: February 2019

A series of greenhouse and field studies was conducted over 9 years to characterize three new sources of resistance in cowpea [Vigna unguiculata (L.) Walp.] to the southern root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] and to determine if the resistances are conditioned by genes allelic to the Rk root-knot nematode resistance gene in `Mississippi Silver'. Three plant introductions (PI), PI 441917, PI 441920, and PI 468104, were evaluated for reaction to M. incognita in four greenhouse tests, and in every test each PI exhibited less galling, egg mass formation, or egg production than `Mississippi Silver'. F2 populations of the crosses between `Mississippi Silver' and each of the three resistant PIs were also evaluated for root-knot nematode resistance in a greenhouse test. None of the F2 populations segregated for resistance, indicating that PI 441917, PI 441920, and PI 468104 each has a gene conditioning resistance that is allelic to the Rk gene in `Mississippi Silver'. Our observations on the superior levels of resistances exhibited by PI 441917, PI 441920, and PI 468104 suggest that the allele at the Rk locus in these lines may not be the Rk allele, but one or more alleles that condition a superior, dominant-type resistance. The availability of additional dominant alleles would broaden the genetic base for root-knot nematode resistance in cowpea.
Screening Tomato Seedlings for Resistance to Bacterial Spot
Authors: Somodi G. Cameron , Jones J.B. , Scott J.W. , Jones J.P.
Published: February 2019

A `spray-inoculation seedling screening procedure was developed for detecting resistance to Xanthomonas campestris pv. vesicatoria (Doidge) Dye, causal agent of bacterial spot of tomato (Lycopersicon esculentum Mill.). Two-week-old transplants were preconditioned under 95% humidity for 16 hours before spray inoculation and then rated for bacterial spot 2 weeks later. Resistant plants could also be distinguished from susceptible genotypes using a modified bacterial speck [Pseudomonas syringae pv. tomato (Okabe) Young, Dye, and Wilkie] screening procedure (cotyledon-dip technique). When results of both screening methods were compared to field ratings from three previous seasons, significant correlations were more frequently observed for the spray-inoculation method. In Summer 1991, individual plants were evaluated by the spray-inoculation technique and then were placed in the field to determine susceptibility under field conditions. Correlations (r = 0.28 to 0.34) between spray-inoculation seedling screening ratings and field ratings, although low, were significant (P ≤ 0.0001). More than 90% of susceptible plants could be eliminated, saving labor, space, and time.
Oscillatory Transpiration May Complicate Stomatal Conductance and Gas-exchange Measurements
Authors: Rose Mary Ann , Rose Mark A.
Published: February 2019

A closed-loop photosynthesis system and a heat-balance sap-flow gauge independently confirmed oscillatory transpiration in a greenhouse-grown Rosa hybrids L. Repetitive sampling revealed 60-minute synchronized oscillations in CO2-exchange rate, stomatal conductance, and whole-plant sap-flow rate. To avoid confusing cyclical plant responses with random noise in measurement, we suggest that gas-exchange protocols begin with frequent, repetitive measurements to determine whether transpiration is stable or oscillating. Single measurements of individual plants would be justified only when transpiration is steady state.
EVALUATION OF VIGNA UNGUICULATA GERMPLASM FOR RESISTANCE TO MOSAIC VIRUSES
Authors: Chambliss Oyette L. , Hunter Arthur G. , Hampton Richard O.
Published: February 2019

Germplasm accessions and advanced lines were evaluated for seed transmission of the seed borne viruses, cucumber mosaic (CMV), cowpea severe mosaic (CSMV), and blackeye cowpea mosaic (B1CMV). Seed samples from 822 field plots (274 out of 300 accessions in 3 replications) which had been evaluated for insect resistance in 1992 were planted in the greenhouse. Mosaic virus symptoms had been apparent throughout the 1992 field planting. Evaluation for mosaic symptoms was done at the seedling stage in the greenhouse and 89 entries exhibited seed borne virus symptoms in one or more plants. Of these, 78 were shown by ELISA (enzyme linked immunosorbant assay, direct antigen coating method) to contain at least one of the seed borne viruses for which we were evaluating.
KENAF FIBER CORE MEDIA AND DOLOMITE LEVELS INFLUENCE PLANT GROWTH OF CONTAINER-GROWN GARDEN CHRYSANTHEMUM
Authors: Lamb Julia L. , Quarrels Jesse R. , Newman Steven E.
Published: February 2019

Kenaf (Hibiscus cannabinus L.) is a member of the Malvaceae family cultivated primarily for its bast fibers. The objective of this study was to evaluate kenaf fiber core as a substitute for vermiculite in a sphagnum peat moss-based medium. Rooted cuttings of Dendranthema x grandiflora were planted into 1 liter pots containing six sphagnum peat moss-based media modified with fine or coarse, fresh or aged kenaf core and/or vermiculite. The media were (by volume): 5 peat: 5 vermiculite: 0 kenaf, 5 peat: 4 vermiculite-1 kenaf; 5 peat: 3 vermiculite: 2 kenaf; 5 peat: 2 vermiculite: 3 kenaf; 5 peat-1 vermiculite: 4 kenaf; and 5 peat: 0 vermiculite: 5 kenaf, Dolomite was added at five rates 0, 1.5, 3, 4.5, and 6 kg/m3. Gypsum was added to each medium combination to provide equal calcium levels for all treatments. The medium with no kenaf grew the tallest plants. Kenaf that was aged and finely ground produced plants similar in height to controls. Fresh kenaf was detrimental to plant growth. Dolomite ameliorated the fresh kenaf effect slightly.
HERBICIDE-BLENDED AND COATED FERTILIZER EFFECTIVELY CONTROLS PROSTRATE SPURGE IN CONTAINERS
Authors: Crossan C.K. , Gilliam C.H. , Keever G.J. , Eakes D.J.
Published: February 2019

Herbicide-blended and coated fertilizers were evaluated for prostrate spurge control in containers. Ronstar 2G or Pennant 5G was blended with Nursery Special 12-6-6 fertilizer and Ronstar 50WP or Pennant 7.8E was sprayed on the fertilizer (coated). Ronstar 2G-blended fertilizer and Ronstar. 50WP-coated fertilizer provided weed control at the 4, 8, and 16 lb ai/A rates similiar to broadcast (2G) or sprayed (50WP) herbicide applied at the label rate (4 lb ai/A). Ronstar provided better prostrate spurge weed control than Pennant. Formulation had no affect on weed control when comparing blended or coated fertilizer. Herbicide-blended and coated fertilizers provided effective prostrate spurge contol in containers.
SEEDING AND COVERING DATES FOR PRODUCING `TEXAS GRANO 1015Y' ONION TRANSPLANTS UNDER ROW COVERS
Authors: Bender David A.
Published: February 2019

Field production of adapted transplants could allow West Texas growers to meet the strong demand for `Texas Grano 1015Y' onions in June. A trial was conducted to determine optimal timing for seeding and covering field beds with row covers to produce transplants for planting in early March. Onions were seeded in drip-irrigated field beds at 10-day intervals from mid-October to mid-November and covered with 4-mil polyethylene tunnels at 10-day intervals from mid-November to mid-December. Plants were evaluated on 11 March and transplanted into field plots with greenhouse-grown plants. Seeding in October or covering in mid-November produced acceptable 4-leaf transplants by early March. Plant height, dry weight, number of leaves and survival decreased as seeding or covering was delayed. In field trials, row cover plants produced equal yields and only slightly smaller bulbs than greenhouse plants. Despite the large size of some of the field-grown transplants, no bolting was observed.
SIMULTANEOUS SCREENING FOR VIRUS AND NEMATODE RESISTANCE IN SOUTHERNPEA, VIGNA UNGUICULATA
Authors: Hunter A. G. , Chambliss O. L.
Published: February 2019

Screening for resistance to blackeye cowpea mosaic virus (BlCMV) and rootknot nematode on the same plant is possible if the two pathogens do not interact significantly. To determine if such interactions were present four cultivars were planted in 72-cell styrofoam flats, with a combination of BlCMV and nematode inoculations (--, -+, +-, and ++). `Freezegreen' is known to be susceptible to both pathogens, `Mississippi Silver' is resistant to both, `California Blackeye #5' is susceptible to BlCMV, and `Worthmore' is resistant to BlCMV. Nematode treated seeds were inoculated at planting with 2,000 eggs of (Meloidogyne incognita Race 3); BlCMV was inoculated on primary leaves a week later. Plants were visually rated for symptoms: either negative or positive for BlCMV and 1-5, no galls and heavily galled respectively, for rootknot. Analyses of variance using percentage of plants negative for virus symptoms or average nematode score as the dependent variable, resulted in non-significant virus × nematode interactions. Results by cultivar indicated simultaneous screening did not change their resistance/susceptible classifications.
TOMATO TRANSPLANT AGE AND METHOD OF PLANT HARDENING AFFECT YIELD
Authors: Roberts Warren , Duthie Jim , Watkins Wes
Published: February 2019

Wet soils can prevent growers from transplanting tomatoes at the ideal size and age. Experiments were conducted to determine the length of time that transplants can be held before yield is reduced Also, different techniques for holding and hardening plants were compared. Seven ages of `Sunny' tomato plants (4, 5, 6, 7, 8, 9, 10 weeks old at transplanting) were either grown normally, grown with limited water, or grown with limited fertilizer. Plants were grown in trays containing 128 cells, with each cell approximately 3.2 by 3.2 by 11 cm. Water was applied for 3 minutes either once a day or twice a day. Fertilizer (20-20-20) was applied either once a week or once during the entire seedling production period. Transplants were later planted in the field. The experiment was conducted in 1990, 1991, and 1993. The yield response to transplant age was quadratic, with maximum yield occurring with 6, 7, and 8 week old transplants. In general, the greatest yield occurred when water was withheld, and the lowest yield occurred when fertilizer was withheld from the transplants
DIFFERENTIAL FRUIT DETACHMENT FORCE OF MATURE CAYENNE PEPPER SELECTIONS
Authors: Gersch Kay P. , Motsenbocker Carl E. , Lang Gregory A.
Published: February 2019

Cayenne pepper fruit adhere tightly to the calyx/receptacle, increasing the cost of hand harvest and restricting mechanical harvest. Eight (8) cayenne pepper genotypes were selected from field observations to characterize fruit detachment forces(FDFs) and examine potential relationships between FDF and other fruit parameters. A preliminary greenhouse experiment revealed two genotypes with consistently lower FDFs and two with consistently higher FDFs over several progressive harvest. A field experiment confirmed these characteristics. No correlation between any fruit parameter and FDF was found to be consistent over the genotypes studied.
PERFORMANCE OF CALABAZA (CUCURBITA MOSCHATA) HYBRIDS
Authors: Maynard Donald N. , Elmstrom Gary W. , Wessel-Beaver Linda
Published: February 2019

Hybrids from crosses between bush/short-vined breeding lines and traditional, vining cultigens were evaluated in the fall 1993 season. Yields of individual hybrids were 0.51 to 1.73 times those of their vining parents and 0.83 to 4.41 times those of the bush/short-vined parents. The average yield response of 58 hybrids was 1.05 times that of vining parents and 2.15 that of bush/short-vined parents. Average fruit weight, flesh thickness, and flesh color of the hybrids tended to be intermediate between that of the bush/short-vined and vining parents. Plant habit of all hybrids was similar to that of the bush/short-vined parent early in the growth cycle, but some became viney later in the growth cycle. Fruit matured earlier on bush/short-vined parent and hybrid plants than on viney parent plants.
TWO YEARS OF RESULTS ON THE INFLUENCE OF GROWING SEASON TEMPERATURES ON FATTY ACID PROFILES AND OIL CONTENT OF FOUR PECAN CULTIVARS
Authors: Sistrunk L. , Chapman D. , Storey J. B.
Published: February 2019

Pecan nuts from eleven different locations ranging from 1000 heat units at Chetopa, Kansas during the twelve weeks prior to shuck split to 1675 heat units in Zavala County, TX. Monounsaturated and polyunsaturated fatty acids increased and decreased respectively in `Mohawk' in 1991 and 1992 as the temperature increased during the kernel development period Fatty acids in `Pawnee' responded the same as in `Mohawk' in 1992 but were variable in 1991. Limited data showed a reversal of mono and polyunsaturated fatty acids in `Osage' in response to kernel development temperature. Higher temperatures caused the testas of `Cheyenne' to be darker in 1991 and 1992. Total oil content of `Mohawk' increased heat units. However, higher temperatures decreased oil content in `Pawnee'. Clinical evaluation of pecans is needed to confirm Grundy's safflower work.
DELAYING BLOOM OF `LORING' PEACH BY FALL APPLICATION OF GIBBERELLIC ACID, ETHEPHON, AND GIBBERELLIC ACID PLUS ETHEPHON
Authors: Caylor A. , Dozier W. , Himelrick D. , Pitts J. , Chapman L.
Published: February 2019

Four year old `Loring' peach trees on `Lovell' rootstock were treated with single applications of 0, 50, and 100 ppm GA3 alone and in combination with 100 ppm ethephon on 15 November 1988, 1989, and 1990 to determine the effect on bloom delay the following spring. Flower bud number was not affected by any of the treatments the next spring. Ethephon had the greatest effect on bloom delay the following spring. The 50 and 100 ppm GA3 treatments resulted in a slight delay of bloom. The combination of 50 and 100 ppm GA3 and 100 ppm ethephon resulted in less of a bloom delay than ethephon alone but greater than the GA3 treatments alone. Fruit set was increased by ethephon treatments in 1989 and 1991 but not in 1990. Ethephon treatments delayed fruit maturity whereas GA3 did not. Total fruit yield for 1989, 1991, and the three year average was not effected by treatments. However, in 1990 50 ppm GA3 resulted in the highest yields. Ethephon treatments reduced the average fruit weight in 1990 and 1991 but not in 1989 or the three year average.
COLD DAMAGE OF APPLE BUDS AND SPURS FOLLOWING TREATMENT WITH DORMANT OIL
Authors: Myers R.E. , Deyton D.E. , Sams C.E.
Published: February 2019

Spurs of `Starkspur Delicious' trees were dipped in 0, 3, 6, 9 or 12% petroleum oil (dormant oil) or soybean oil emulsions on 26 January 1993. The spurs were cooled at 3C/hr until -9C or kept at 21C. After treatment, the flower buds on spurs were forced at 20C for 11 days and then dissected. The cambium and xylem of the spurs and the interior of the flower buds were rated for damage as indicated by browning. The experiment was repeated at the silver tip stage of buds (early March) except that treated spurs were exposed to 20C, -6C, or -9C. Neither the oil treatments nor low temperature exposure caused visual damage to flower buds or cambium in January. However, the oil treatments damaged flower buds at the silver tip stage (March). Neither petroleum or soybean oil caused visible damage to the xylem or cambium of the spurs.
PROPAGATION OF AMARYLLIS BULBS BY TWIN SCALING
Authors: Klingaman Gerald L. , Henderson Troy
Published: February 2019

Amaryllis bulb production is conducted in Africa, and to a lesser extent in Central America, Holland and Israel. Preliminary studies have shown bulb production is feasible in zone 6b using unheated greenhouses and thermal blankets during cold periods. Spun bound polyester (Reemay) and polystyrene foam (Sentinel) provided a maximum of 9C protection over outside conditions. Amaryllis bulbs have been uninjured during two successive winters. A twin scale propagation experiment was conducted on the cultivar Appleblossom. Cuttings 15mm wide that were placed in closed, vermiculite-filled plastic bags or uncovered, vermiculite-filled plastic trays produced 1.5 bulbs per cutting. Cuttings 7.5mm wide that were placed in soil in plastic bags or open flats averaged .34 bulbs per cutting. From 75 to 80 bulblets were produced per mother bulb using wide cuttings in soil or vermiculite or narrow cuttings in vermiculite.
MECHANICAL IMPULSE RESPONSE AS A MEASURE OF TOMATO FRUIT MATURITY
Authors: Chrz D. , Maness N. , Chen D. , Stone M.
Published: February 2019

A mechanical impulse system for determining tomato fruit maturity and size was tested, for development of a rapid, nondestructive fruit testing instrument. Fruit were grouped into various maturity categories, ranging from immature green to red, and impulse spectra were obtained at a site over the locule at marked locations. Resistance to puncture was measured on the locular side of the pericarp wall at the same locations. A sonic resonant frequency band was weakly correlated with fruit maturity category. Stronger correlations existed with pericarp puncture resistance and fruit weight. A description of essential components and utilization of the instrument for fruit firmness determination will be presented. Supported by OCAST (Oklahoma Center for the Advancement of Science and Technology) grant AR2-069, USDA grant 92-34150-7190 and the Oklahoma Agricultural Experiment Station.
EFFECT OF IRRIGATION AND PRETRANSPLANT INOCULATION OF VESICULAR-ARBUSCULAR MYCORRHIZAL (VAM) FUNGI ON POSTTRANSPLANT GROWTH OF PROSOPIS ALBA GRIEB
Authors: Martin Chris A. , Stutz Jean C.
Published: February 2019

Prosopis alba (mesquite) in 27-liter containers, either infected or noninfected with the VAM fungi, Glomus intraradix Schenk & Smith, during the container production phase were transplanted into a simulated landscape and irrigated at regular intervals or nonirrigated (irrigated only once at transplanting time). Mesquite shoot extension (SE), trunk diameter, rooting density (RD), specific root length density (SRLD), and VAM colonization levels were measured at 6 months and 1 year after transplanting. At 6 months, VAM colonization was observed only in the roots of inoculated mesquite, but by 12 months, roots of inoculated and noninoculated mesquite were colonized by VAM fungi. There were higher levels of VAM colonization in roots of irrigated mesquite (23%) in comparison to nonirrigated mesquite (5%). Irrigation promoted SE and VAM inoculation inhibited SE of nonirrigated trees. Trunk diameter was greater for irrigated trees than for nonirrigated trees and was not affected by VAM fungal treatment. At 6 months after transplanting, VAM fungal and irrigation treatments interacted to affect mesquite RD and SRLD. For irrigated mesquite, RD and SRLD were highest for VAM-inoculated mesquite, whereas for nonirrigated trees, RD and SRLD were highest for noninoculated trees. At 12 months after transplanting, mesquite RD and SRLD were higher for irrigated than for nonirrigated trees and were not affected by previous VAM inoculation.
SHORT TDR PROBES TO MEASURE WATER AND FERTILIZER ION GRADIENTS IN CONTAINER MEDIA
Authors: Kelly Shaun F. , Green J.L , Selker John S.
Published: February 2019

Time Domain Reflectometry (TDR) is used to measure in situ soil moisture content and salinity of porous media. Commercially available TDR systems used for field measurements have limited use in laboratory scale experiments where short high resolution probes are needed. A short TDR probe was designed for use with high bandwidth TDR instruments currently available. The probes are designed from SMA bulkhead connectors using gold-plated stainless steel wire 0.035 inches in diameter. A 20.GHz digital sampling oscilloscope (11801; Tektronix, Beaverton, Ore.) with an SD-24 TDR sampling head is used with the probes to determine water content and ion concentrations in porous media. The 7.5- and 3.0-cm-long probes were used to measure soil moisture content and ion concentrations in laboratory columns. Fertilizer and water gradients were observed by using bromide salts brought into contact with the top of laboratory columns, 7.6 cm in diameter and 18 cm long, packed with container media [1 peat: 1 vermiculite v/v)]. Soil moisture measurements in the presence of high concentrations of salts were made by insulating the probes with Teflon heat-shrinkable tubing to minimize conductivity losses.
CREATING A PROTECTED DIFFUSION ZONE
Authors: Green James L.
Published: February 2019

In intensive, open horticultural crop production systems, quantities of water and soluble fertilizers are convected by gravitational and evaporative flow through the plant root zone, with only a small fraction being captured by the plant root system. Principles and concepts developed in creating a protected diffusion zone (PDZ) within the closed, insulated pallet system (CIPS) have been extrapolated to create a protected zone for fertilizer diffusion in a surface-irrigated plant container or open field/landscape planting. Incorporating additional evaporative and gravitational water flow barriers has resulted in a semiclosed field system to minimize quantities of water and fertilizer applied and lost from the plant root zone. Use of saline water is more feasible in PDZ system than in open systems.
INHERITANCE OF VERTICILLIUM WILT RESISTANCE IN PI 215699, AN CAPSICUM ANNUUM ACCESSION
Authors: González-Salán Max M. , Bosland Paul W.
Published: February 2019

The segregation ratios for verticillium wilt resistance in PI 215699 suggests that verticillium wilt resistance is a quantitative trait. Additive and dominance genetic variance effects were studied. The F1, F2, F1 B Cr, and F1 B Cs, using the resistant parent (Pr) and the susceptible parent (Ps), PI 215699, and BG. 1668, respectively, were accomplished. The plants were grown in soil temperature tanks with a 25 ± 1C soil temperature, an inoculum level of 2000 microsclerotia of Verticillium dahliae Kleb. per gram of soil, and 18 hours of 250 umol·m-2 · s-1 light. The experiment consisted of four replications with 30 plants per replication for each generation. The seedlings were individually scored 70 days after sowing for an interaction phenotype score (IP) using a scale ranging from 1 to 9 in which 1 = no aerial symptoms and 9 = death. Means, variance, and standard deviations for the percentage of resistant plants (IP = 1) were calculated. A joint three-factor scaling test to estimate the parameters [mid-parent value (m), additive effects (d), and dominance effects (h)] revealed that the data did not fit a simple additive-dominance model. Epistasis was suspected to be present and a joint six-factor model was therefore tested. The joint six-factor model estimates m, d, h, and three epistatic interactions parameters [additive × additive (i), additive × dominance (j), and dominance × dominance (1)]. All epistatic interactions parameters were significant. These results indicate that additive and epistasis effects were involved in the genetic control of verticillium wilt resistance in PI 215699. Broad-sense and narrow-sense heritabilities for percentage of resistant plants in population PI 215699 were estimated to be 0.81 and 0.48 after 70 days of sowing, respectively.
CHILLING HOUR ACCUMULATION MODELS AND CALENDAR DATE USED TO PREDICT ROOTING OF WHITE FIR STEM CUTTINGS IN NORTHERN NEW MEXICO
Authors: Harrington J.T. , Wagner A.M. , Murray L.W.
Published: February 2019

Historically, calendar date has been used to determine when cuttings are collected for rooting. However, year-to-year variations in climate limits the usefulness of using calendar date. More recently, rooting of stem cuttings has been associated with chilling accumulation. In the winter, daily temperatures in northern New Mexico can fluctuate from below freezing to well above freezing. Eight chilling accumulation models and calendar date were tested to determine the best predictor of rooting of white fir. The chilling accumulation models ranged from those based on number of hours at low temperatures to weighted models that calculated chilling unit accumulation and loss. In addition, temperature data based on 3-, 6-, 12-, and 24-hour averages were used. Most of the models were better than calendar date in predicting rooting. The best model was a weighted model that accumulated chilling from -5 to 10C with loss of chilling >15C and less than -10C. Other models that performed well included models that accumulated chilling from 0 to 7.2C, 0 to 15C, or -3.5 to 10C. On the average, the data based on 12-hour means was the best for modeling chilling accumulation to predict rooting.
Growth and Ectomycorrhizal Development of Northern Red Oak Seedlings Treated with IBA
Authors: Crunkilton D.D. , Garrett H.E. , Pallardy S.G.
Published: February 2019

Ectomycorrhizal and nonmycorrhizal, glasshouse-grown northern red oak seedlings (Quercus rubra L.) received root treatments of IBA in starch, fired-montmorillonite clay, or starch-encapsulated montmorillonite clay. Clay proved to be superior to starch as a carrier for IBA, inducing significant increases in diameter, root length, leaf area, and shoot dry weight. Positive growth interactions between mycorrhizae and IBA were found with the clay carrier. The typical bare-rooted red oak seedling (grown for 1 year in nurseries and outplanted) performs poorly because of insufficient root size. Container-grown seedlings produced using clay/IBA treatments may perform better under field conditions than stock grown conventionally. Chemical name used: indole-3-butyric acid (IBA).
Characteristics of Fire Blight Cankers following Shoot Inoculations of Three Apple Cultivars
Authors: Biggs A.R.
Published: February 2019

Three apple (Malus domestics Borkh.) cultivars varying in susceptibility to Erwinia amylovora (Burr.) Winslow et al., the causal agent of tire blight, were inoculated at biweekly intervals during the growing season. Data were collected on percent infection, canker length, and canker margin quality (a reflection of the overwintering status of the infection). There was a significant cultivar × noculation date interaction, indicating that cultivars that are more susceptible to the pathogen are more likely to develop cankers with indeterminate margins. For `Cortland' and `Jonathan', but not `Delicious', there was a significant linear trend toward forming indeterminate cankers as inoculations were made later in the season. Cankers initiated earlier in the season were more likely to be determinate, which suggests that later-season infections on susceptible cultivars carry over inoculum to the following season. No specific switch-over period from determinate- to indeterminate-type cankers could be identified, and canker margin qualities changed gradually during the growing season. As expected, `Delicious' appeared resistant to tire blight in this study, based on percent infection, canker length, and canker margin type, whereas `Cortland' and `Jonathan' appeared moderately and highly susceptible, respectively. `Delicious' was more likely to form cankers with determinate margins, which suggests that cankers formed on this cultivar are less likely to produce inoculum in the spring than the other two cultivars.
Mechanical Thinning of Peaches is Effective Postbloom
Authors: Glenn D. Michael , Peterson Donald L. , Giovannini Daniela , Faust Miklos
Published: February 2019

Hand-thinning (Prunus persica L. Batsch) “Y”-trained peach trees at bloom and 51 days after full bloom (DAFB) was compared to mechanical fruit thinning 51 DAFB using a spiked-drum and an impact shaker. The spiked-drum shaker removed more fruit from horizontal branches than from vertical branches, yet did not selectively remove either large or small fruit. Bloom thinning by hand increased fruit size compared to postbloom thinning 51 DAFB, and both postbloom mechanical thinning techniques were as effective as postbloom hand thinning. The spiked-drum shaker may be a better thinning technique than the impact shaker because it transfers less shaking energy to the fruit, can be used in high-density plantings, and does not contact the trunk, lessening the potential for tree damage.
Seed Geranium Growth and Flowering Responses to Uniconazole
Authors: Starman Terri Woods , Cerny Teresa A. , Grindstaff Tracy L.
Published: February 2019

Height control and flowering responses to uniconazole spray or drench treatments were measured for `Multibloom Scarlet' and `Red Elite' geranium (Pelargonium ×hortorum L.H. Bailey). Total plant height of both cultivars was reduced proportionately to the height of a 10-cm container when the uniconazole drench concentration was 0.025 mg a.i./pot. Used as a spray, uniconazole was not as effective in restricting total plant height of either cultivar. Foliage height was shortened more than inflorescence height. Inflorescence diameter was decreased with increasing uniconazole drench concentrations. Sprays did not affect inflorescence diameter of either cultivar. Uniconazole effect on days to flower varied with cultivar and application method. Chemical name used: (E)-(S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ene-3-ol (uniconazole).
Pepper Transplants Are Excessively Damaged by Brushing
Authors: Latimer Joyce G.
Published: February 2019

`Jupiter' or `Marengo' pepper (Capsicum annuum L.) seedlings maintained under 0%, 30%, 50%, or 80% shade in a greenhouse were brushed 80 strokes twice daily beginning at the cotyledonary, first true leaf, or second true leaf stage. Averaged across shade environments, brushing reduced `Jupiter' and `Marengo' stem length 25% to 36% and 6% to 28%, respectively. However, the percentage of plants exhibiting mechanical damage by brushing ranged from 86% to 93% and 48% to 90% for `Jupiter' and `Marengo', respectively. Transplant quality tended to decrease as brushing was delayed. When brushing of `Marengo' was reduced to 40 strokes twice daily in 1992, plant growth reduction decreased, but the percent damage was about the same. The damage severity, however, was reduced as indicated by higher plant-quality ratings. Pepper plant damage was excessive for the small amount of growth regulation provided by brushing.
Evaluation of the Motherstalk Method of Asparagus (Asparagus officinalis L.) Production in a Greenhouse
Authors: Reiners Stephen , Garrison Stephen A.
Published: February 2019

The motherstalk method of `Jersey Centennial' asparagus production was examined in two greenhouse studies. This technique allowed for one, two, or three spears to develop a mature fern while permitting harvest of later-developing spears. Cumulative yield was highest 10 weeks after planting with one and two motherstalks, and crown dry weights in these treatments were similar to those of the nonharvested treatment. In a second experiment, spear yield and crown dry weight were determined when the motherstalk was initiated at 0, 2.5, and 5 weeks after planting. Yields were highest when the motherstalk was established at week 0 or 2.5 compared to week 5. Crown dry weights of early motherstalk treatments were similar to those of the nonharvested treatment at the end of the 10-week harvest period. Our results indicate that the motherstalk system may allow for extended asparagus harvest in temperate areas.
Combined Heating Applications Increased Plant Production from Bedded Sweetpotato Roots
Authors: Hall Melvin R.
Published: February 2019

`Red Jewel' sweetpotato [Ipomoea batatas (L.) Lam.] roots were cured [32 ± 1C, 85% relative humidity (RH)] for 7 days immediately after harvest and then subjected to selected single or combined applications of additional curing, midstorage heating, and presprouting not to exceed 21 days. Extended curing was applied for 0, 7, 14, or 21 additional days before storage (16 ± 1C, 85% RH). Midway through storage, roots were heated (32 ± 1C, 85% RH) for 0, 7, 14, or 21 days and placed back into storage. Before being bedded, roots were presprouted (32 ± 1C, 85% RH) for 0, 7, 14, or 21 days. Roots that received extended curing, midstorage heating, or presprouting or a combination of these treatments emerged earlier and produced more cumulative early, midseason, and total plants than nonheated roots. Roots heated once for 21 days produced more plants than roots heated once for 14 days; those heated for 21 days in a combination of short durations produced more early, midseason, and total number of plants than roots heated once for 21 days.
Circadian Rhythm of Carbon Dioxide Production by Anthurium Flowers
Authors: Hew C.S. , Ong T.K. , Yap W.P.
Published: February 2019

A circadian rhythm in CO2 production was observed in three cultivars of Anthurium andraeanum Andre (`Jaya', `Fla-range', `Leonette') flowers. The rhythmicity was not affected by light, darkness, and detachment. However, the amplitude was dampened in darkness and after detachment. Spadix respiration accounted for 90% of the total flower respiration. Rhythmicity in CO2 production continued after spathe removal. Less pronounced rhythmicity was observed following spadix removal.
Prestorage Low-oxygen Atmosphere Treatment Reduces Chilling Injury Symptoms in `Fuerte' Avocado Fruit
Authors: Pesis Edna , Marinansky Rosa , Zauberman Giora , Fuchs Yoram
Published: February 2019

Prestorage treatment of avocado fruit (Persea americana Mill. cv. Fuerte) with a low-O2 atmosphere (3% O2 + 97% N2) for 24 hours at 17C, significantly reduced chilling injury (CI) symptoms after storage at 2C for 3 weeks. Fruit softening was also delayed by this treatment. The treated fruit had lower respiration and ethylene production rates during storage at 2C and subsequently at 17C. Electrolyte leakage was significantly lower in peel disks from treated fruit. Reducing power, expressed as total sulfhydryl groups, was higher in the peel and pulp of low-O2-treated fruit. The amount of peel chlorophyll was inversely correlated with the severity of CI symptoms.