bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrotropism in Pea Roots in a Porous-tube Water Delivery System
Authors: Takahashi Hideyuki , Brown Christopher S. , Dreschel Thomas W. , Scott Tom K.
Published: February 2019

Orientation of root growth on earth and under microgravity conditions can possibly be controlled by hydrotropism-growth toward a moisture source in the absence of or reduced gravitropism. A porous-tube water delivery system being used for plant growth studies is appropriate for testing this hypothesis since roots can be grown aeroponically in this system. When the roots of the agravitropic mutant pea ageotropum (Pisum sativum L.) were placed vertically in air of 91% relative humidity and 2 to 3 mm from the water-saturated porous tube placed horizontally, the roots responded hydrotropically and grew in a continuous arch along the circular surface of the tube. By contrast, normal gravitropic roots of `Alaska' pea initially showed a slight transient curvature toward the tube and then resumed vertical downward growth due to gravitropism. Thus, in microgravity, normal gravitropic roots could respond to a moisture gradient as strongly as the agravitropic roots used in this study. Hydrotropism should be considered a significant factor responsible for orientation of root growth in microgravity.
Market Segmentation of Supermarket Floral Customers
Authors: Behe Bridget K. , Prince Timothy A. , Tayama Harry K.
Published: February 2019

A profile of consumer groups who purchased floral products from supermarkets was studied with a 106-item questionnaire developed to determine the domain of issues affecting supermarket floral purchases. Thirty-four factors were identified in factor analysis and formed the basis for cluster analysis. Cluster analysis was performed on survey responses to create five homogeneous consumer segments. Demographic data and floral-purchase factors were used to profile market segments and distinguishing elements. Fourteen factors contributed most to the differences between segments, including factors of product assortment, number of purchases, degree of personal use, and package importance. Clusters can be used by supermarket and florist management as potential target markets.
GROWTH OF KENTUCKY COFFEE TREE SEEDLINGS IN PROTECTIVE SHELTERS DURING FIELD ESTABLISHMENT
Authors: Kjelgren Roger , Foutch Mike
Published: February 2019

Growth and water relations of seedlings grown in protective tree shelters were investigated during establishment in a field nursery. Shelters, 1.2 m high, were placed over 0.5 m Kentucky coffee tree seedlings following spring transplanting in a field experiment. Predawn leaf water potential (ψ) and stomatal conductance (gs) were monitored periodically through the season and growth was measured in late summer. In a second experiment diurnal microclimate, and seedling water relations and use, in the shelters were studied under controlled conditions. In the shelters, leaf and air temperature, humidity, and gs exceeded non-sheltered levels while solar radiation was 70% lower. Despite greater gs, normalized water use was 40% lower in the sheltered trees. While midday gs was similarly high in the field-grown trees, no differences in predawn ψ were detected through the season. Sheltered trees in the field had four times more shoot growth but 40% less caliper growth. Sheltered trees had leaf thickness lower than control trees, and together with the growth and radiation pattern, indicated that they were shade acclimated. Shelters can improve height growth and reduce water loss during establishment, but may not allow sufficient trunk development or taper for upright support
SULFUR UPTAKE AND UTILIZATION IN SHORT-DAY ONION CULTIVARS
Authors: Randle William M.
Published: February 2019

Sulfur fertility influences flavor in onions. To determine how sulfur is utilized by onions over the course of growth and development, five short-day onion (Allium cepa L.) cultivars were grown at high (4.0 mequiv.liter-1) and low (0.1 mequiv. liter-1) sulfur fertility regimes under greenhouse conditions. Plants were measured for foliar sulfur content at 4 week intervals during the course of the growing season and for bulb sulfur and pyruvic acid development at plant maturity. Patterns of sulfur uptake and utilization were similar for all five cultivars but cultivars differed in their magnitude of sulfur accumulation. Foliar sulfur accumulation correlated poorly with bulb sulfur and pyruvic acid development at all sampling dates.
COMPARISON OF IN-FIELD TECHNIQUES FOR MONITORING PLANT AND SOIL NITROGEN STATUS
Authors: Hartz T.K. , Smith R.F. , Schrader W.L.
Published: February 2019

California vegetable growers are adopting drip irrigation at an accelerating pace, which affords the opportunity for more exacting control of nitrogen nutrition. Consequently, the need for quick, accurate, grower-friendly techniques for monitoring nitrogen status in soil and plant material has increased. Three field monitoring techniques were examined in detail: the analysis of soil water samples drawn by soil solution access tubes (SSAT). leaf reflectance as measured by the Minolta SPAD 502 chlorophyll meter, and petiole sap analysis with a Horiba portable nitrate-selective electrode meter. Nitrate concentration in soil solution was highly stratified in drip-irrigated soils, both with regard to location in the field and position with respect to the drip line, making the use of SSAT technology impractical as a tool for routine N fertigation scheduling. Correlation of SSAT nitrate values to any measure of plant N status was poor. Similarly, leaf reflectance correlated poorly with any measure of tissue N in the crops examined. Nitrate content of petiole sap was highly correlated with conventional laboratory analysis of dry petiole tissue over a range of crops and nitrogen levels.
MICROPROPAGATION OF CHOKECHERRY AND PINCHERRY (Prunus virginiana and P. pensylvanica)
Authors: Pruski Kris , Lewis Tina , Mirza Mohyuddin
Published: February 2019

Chokecherries and pincherries are commonly used in landscaping. Some of the selections such as `Garrington', `Mary Liss' and `Jumping Pound' have large fruits of good quality suitable for food processing. The species are also very well adapted to severe winter conditions of the Prairie Provinces. In our studies, in vitro propagation of the selections was undertaken. The best results with initiation of cultures were observed when dormant buds were used as explants on MS medium with 30 g/L sucrose, 0.1 mg/L NAA and 1.0 mg/L BAP (4 wks, 24/22°C day/night, 16 hrs photoperiod 3000 lux). Optimal proliferation in both species was on MS medium with 1-2 mg/L BAP, 80 mg/L AdSO4 and 170 mg/L NaH2PO4. Rosettes produced were placed on medium without hormones prior to rooting. Rooting was performed ex vitro in root-trainers (soilless mix) on the greenhouse bench under mist. Basal dip in commercial rooting powder Stimroot 1 (0.1% IBA) was equally effective to spray application (2 mg/L IAA with 0.5 mg/L NAA). Average of 77% rooting with `Garrington, 72% and 81% rooting with `Jumping Pound' and `Mary Liss' was observed respectively.
THE EFFECT OF IRRIGATION STRATEGIES ON PEACH FRUIT GROWTH AND FINAL SIZE
Authors: Johnson R. Scott , Phene Claude , Medawar Charles
Published: February 2019

Six irrigation strategies were imposed on a block of O'Henry peach trees irrigated by fanjets. Treatments received different percentages of ET during the various stages of fruit growth and postharvest. ET was estimated by a large weighing lysimeter containing 2 trees and located in the center of the block. Fruit diameters were measured weekly and final fruit weights were determined at harvest. Adjusted fruit weights were estimated by statistically adjusting each treatment to the same fruit load.

Adjusted fruit weight correlated well with soil water content during the month before harvest but not during early stages of fruit growth. Treatments which applied 50% ET during early stages of fruit growth showed reduced fruit size at that time. However, with applications of 150% ET during the final fruit growth stage, fruit size recovered. Adjusted fruit weight also correlated with measures of tree water status including midday leaf water potential and canopy temperature.
ASIAN PEAR (NASHI) TREE WATER RELATIONS IN LYSIMETERS.
Authors: Renquist A. Richard , Caspari Horst W. , Chalmers David J.
Published: February 2019

Nashi pear (Pyrus serotina Rehder, cv. Hosui) trees were planted in 12 computerized 1m-wide drainage lysimeters in September 1987. During the 1990 season tree water use was monitored via lysimeter and neutron probe readings. Diurnal leaf water relations were studied using a pressure chamber for water potential (ψ) and a porometer for leaf conductance (gs). Xylem sap trunk flow velocities were measured with an experimental heat pulse device and converted to xylem flux. Close agreement existed between 24 hr xylem flux and lysimeter water use when comparing trees with different soil water content. Xylem flux also was very sensitive to changes in evaporative demand. During 9–13 day drying cycles pre-dawn ψ became progressively lower, morning decline more rapid, and afternoon recovery slower. The diurnal gs pattern also shifted during drying cycles, such that gs of water stressed trees always decreased from time of first measurement of sunlit leaves rather than increasing during the morning as on non-stressed trees. Late afternoon was the best time to distinguish between fully irrigated and stressed trees using gs measurements.
PARTITIONING OF 14C-SUCROSE INTO SORBITOL UNDER WATER STRESS
Authors: Wang Zhongchun , Stutte Gary W.
Published: February 2019

Previous results showed that active sorbitol accumulation occurs under water stress. We tested the hypotheses that sorbitol accumulation is due to reduced sorbitol export from leaves or from increased synthesis of glucose to sorbitol. To test the hypotheses, 230 μl 14C-sucrose was introduced through the stems to detached `Jonathan' apple shoots which had either water stress or no stress. Following uptake of 14C-sucrose, 0% or 10% PEG was applied to shoots for 24 hours. The results showed that 73% of 14C-sucrose in non-stressed leaves was broken down within 1 hour and 44% was recovered in sorbitol. PEG initially stimulated the breakdown of 14C-sucrose to glucose and fructose, but further conversion to sorbitol was reduced. However, the percentage of 14C-sorbitol in mature leaves increased gradually in 10% PEG until it exceeded that of control at 24 hours. In contrast to mature leaves, young leaves and stems showed significantly less sorbitol under 10% PEG 24 hours after treatment. These results supported the hypothesis that sorbitol accumulation under water stress was due to the reduced sorbitol transport.
ANALYSIS OF RFLP LOCI IN WALNUTS: INHERITANCE, INTRA- AND INTERSPECIFIC VARIATION, AND CULTIVAR IDENTIFICATION.
Authors: Fjellstrom R. , Parfitt D. E.
Published: February 2019

RFLP analysis was employed to study the inheritance of and genetic diversity identified by cloned walnut genomic probes. An interspecific backcross population of (J. hindsii × J. regia) × J. regia was used to determine the inheritance of thirty low copy number RFLP cloned probes. Of these probes, approximately 20% correspond to single copy loci, 40% correspond to single major loci with multiple minor loci, and 40% correspond to two major loci. Twenty of these probes were used to analyze variability within and between 13 walnut species (Juglans spp.). Substantial genetic variation was identified within many wild walnut species, while limited variation was identified within butternut (J. cinerea) and the widely cultivated English walnut (J. regia). Extensive polymorphism was found between walnut species, allowing a phylogenetic relationship of walnuts based upon RFLP markers to be developed. Identification of clonally propagated walnut cultivars by RFLP typing was readily performed in black walnut (J. nigra) accessions, was more difficult in English walnut accessions, and rarely possible in butternut accessions.
INDUCTION OF DORMANCY IN NONDORMANT LETTUCE SEEDS BY GA BIOSYNTHESIS INHIBITORS
Authors: Khan Anwar A. , Andreoli Claudinei
Published: February 2019

Dormancy was induced in nondormant (germinate readily in light or darkness) seeds of several lettuce cultivars (Mesa 659, Emperor, Empress, Montello, Ithaca) by soaking in the dark in 5-100μM tetcyclacis (TCY) for 24h at 25°C as the seeds failed to germinate in the dark upon removal of TCY by washing. Higher concentrations of TCY was needed to induce dormancy in the light Paclobutrazol (PP 333) was relatively less effective. No dormancy was induced in nondormant lettuce seeds soaked for 24h in 100μM ABA as the seeds germinated readily in the dark upon removal of the inhibitor by washing. Thus, contrary to popular belief ABA does not appear to be a dormancy factor. Dormancy induced by TCY was released by soaking seeds in petri plates in water at 25°C in the light, in the presence of 0.001-1mM GA4+7, or by moist-chilling for 4-15d at 5°C. Dormancy was also released when dried dormant (dormancy induced by TCY) Mesa 659 or Emperor lettuce seeds were planted in a moist peat-lite mix in plastic containers and kept moist for 30d at 5°C, as indicated by emergence of normal, healthy seedlings upon transfer of the containers to 25°C. The significance of TCY induced dormancy in altering planting strategy in field plantings of lettuce and other crops will be discussed.
STORAGE OF TRUE POTATO SEED
Authors: Pallais Noël
Published: February 2019

True potato seed of Atzimba × 104.12LB (intermediate dormancy) was dried to seed moisture contents ranging from 3.85 to 12.5% (dry wt basis) and was stored for 2 years at 30, 15 and 5°C. Seed was tested for various germination and seedling vigor criteria at 4 month intervals. Seed dormancy and viability were better preserved at seed moisture levels below 7% and as temperature decreased. High moisture (>9%) was lethal to seed stored at 30°C. TPS should be stored at <5% seed moisture content. Under this condition seed dormancy in the genotype studied was lost after about 12 months at 30°C.
GROWTH, MINERAL NUTRITION, AND LEACHING LOSSES FROM SALINIZED CITRUS TREES
Authors: Syvertsen J.P. , Smith M.L. , Boman B.J.
Published: February 2019

Effects of salinized irrigation water on tree canopy and root growth, water use, foliar nutrition, and leaching losses below the rootzone were studied during a 2-year period using single tree lysimeters. Eighteen 6-year-old `Valencia' orange trees on either Carrizo citrange (CC) rootstock or sour orange (SO) rootstock were each transplanted into 7.8 m3 drainage lysimeters and irrigated with water having an electrical conductivity of 0.3, 1.6, or 2.5 dS m-1 from a 3:1 ratio of NaCl:CaCl2. Six additional trees (3 on each rootstock) were transplanted into soil without tanks. Trees outside the tanks were smaller, but nutritionally similar to the low salinity trees in lysimeters. Trees on CC were larger, had greater root densities, and were associated with less leaching of ions and nutrients into drainage water from the tanks than trees on SO. High salinity irrigation water reduced canopy growth and ET, but increased fibrous root dry weight. Trees on CC accumulated more Cl in leaves and in fruit juice than those on SO. Leaching loss of total N varied from 2-8% of that annually applied to trees, but up to 70% of the applied N and up to 80% of the applied K were leached from the blank tank with no tree. Salinized trees lost more N and K to drainage water, especially those on SO. Tree size, root density, and irrigation water quality can influence leaching losses beyond the rootzone.
IN VITRO PROPAGATION OF PATUMMA (CURCUMA ALISMATIFOLIA GAGNEP.)
Authors: Wannakrairoj Surawit
Published: February 2019

Patumma, a native of Thailand, is a new ornamental crop. Its increased demand for export make the species vulnerable to extinction. Cloning methodology is thus needed for the production of both existing and newly developed clone. Young inflorescent segment and lateral bud from rhizome can be used as explants. For decontamination of the lateral bud, the success was depended both on pre-treatment and disintestation procedure. The bud from dried rhizome was better than one from fresh rhizome. Prior to disinfestation with sodium hypochlorite, pre-treatment of rhizome in 52°C water for 5 minutes could replaced the use of antibiotic. Plantlet were placed on modified MS media with 0, 6.67, 13.32, 19.98 and 26.64 μmol/l benzyladenine (BA) or 0.19, 0.56, 1.67 and 5 μmol/l kinetin. The best multiplication rate of 4.83 fold was obtained when longitudinally-divided rhizome was on the medium with 13.32 μmol/l BA. The result also showed that wild-collected and selected clones responded to the media similarly. When the MS media modified with 13.32, 15.54, 17.76 and 19.98 μmol/l BA in combination with 15, 30 and 45 g/l sucrose were tested, the multiplication rate of non-divided plantlets were all the same. Acclimatization by open the culture vessel for 3 day improved plantlet survival rate ex vitro.
SKIN DISCOLORATION IN PEACH AND NECTARINE FRUIT
Authors: Cheng Guiwen , Crisosto Carlos , Garner David , Johnson Scott , Beede Bob
Published: February 2019

The roles of genetic makeup and `orchard environment' on fruit skin discoloration (SD) were studied on peaches and nectarines. Our data showed that the SD incidence (SDI) varied among cultivars in the same orchard and orchards with the same cultivar. Differences in SD susceptibility were examined on whole fruit and skin disks by using SD-inducing treatments including combinations of physical injury and dipping in different solutions (pH, and metal ions). High SDI was associated with physical injury, high pH, and high metal ion concentration. With the exception of N, the amount of macro- and micronutrients in unwashed fruit skin was not correlated with the SDI. Preharvest sprays influenced the SDI. The peach variety with the highest SDI had the highest total soluble phenols. Total soluble phenols and anthocyanins, however, did not show a strong relationship with the SDI among all cultivars studied. Lack of correlation with total soluble phenols does not exclude the possibility that SD may relate to specific phenol(s).
CALCIUM ALLEVIATION OF BORON TOXICITY IN PRUNUS SPECIES.
Authors: El-Motaium Rawia , Brown Patrick H.
Published: February 2019

Boron toxicity is a wide spread problem especially in arid and semiarid areas of the world. Boron toxicity can result in yield loss of many crop plants, especially stone fruits which are sensitive to high boron concentration. This study was designed to follow the effect of Ca+2 supplementation on partitioning of B at the plant organ level (leaves, stem, roots) and the subcellular level (the cell wall) using the stable isotope 10B.

Results demonstrate that calcium supplementation reduced B accumulation in plum and peach leaves by 31% at the low level (0.25 mM) and by 12% at the high B level (0.50 mM). Results indicate an effect of Ca on the uptake and distribution of 10B between plant organs.

Symptoms of B toxicity in peach (Lovell) include stem die back, necrotic brown spots on the stem and gum formation on the nodes, whereas in plum (Mariana), stem die back and gum formation, as droplets, on the lower leave's surface were the main symptoms.
NITROGEN UPTAKE AND ALLOCATION IN TWO CITRUS ROOTSTOCK SPECIES.
Authors: Lea-Cox John D. , Syvertsen James P.
Published: February 2019

The objectives of this greenhouse study were to determine the rate of nitrogen (N) uptake over a 30 day period, use efficiency and N partitioning within two citrus rootstock species. Sixteen-week old seedlings of Cleopatra mandarin (C. reticulata Blanco) and Swingle citrumelo (C. paradisi × P. trifoliata) were assigned to treatments (harvest day × rootstock species) in a completely randomized design, grown in a Candler fine sand for 6 weeks and fertilized weekly with a N:P:K (5:1:5) plus minor elements solution at 200 mg N · liter-1. A single application of 15NH4 15NO3 (20% 15N) was substituted for a normal weekly fertigation. Six replicate plants of each rootstock species were harvested at ½, 1½, 3½, 7½, 10½ and 30 days after I5N application. Uptake of 15N was more rapid in SC over the first 7½ days (17% of applied) than in CM (11%), but uptake over 30 days was similar (52-53%) for both species. A higher proportion of 15N was found in the photosynthetic tissues of CM (74%) than in SC (48%), whereas a lower proportion was found in the fibrous roots of CM (9%) than SC (22%).
PHOSPHORUS AS AN OLIVE FRUIT LOOSENING AGENT
Authors: Banno Kiyoshi , Martin George C.
Published: February 2019

Olive fruit harvest by mechanical shaking continues to be limited by poor fruit removal - less than 60% removal for most varieties. Whereas foliar spray of ethylene releasing compounds such as ethephon increases fruit removal percent, excessive leaf loss following treatment precludes commercial acceptance of the treatment. A classic case of serendipity has led to the testing of phosphorus as an olive fruit loosening agent. Na2 HPO4 at 25 mM applied via the cut stem of explants leads to massive leaf and fruit abscission. When the P source is applied at 100 mM foliar spray, fruit removal is accomplished with minimal leaf loss. Results of this investigation will cover P source, concentration, genera with abscission response and some indication of mechanism of action.
LOW-TEMPERATURE STORAGE OF BEDDING PLANT PLUGS
Authors: Heins Royal D. , Lange Nathan , Wallace Thomas F.
Published: February 2019

Ageratum, begonia, marigold, and salvia seedlings in plug cells were stored in coolers to determine the effects of temperature, light, and storage time on growth and forcing time of seedlings after transplanting, and to determine the optimum storage temperatures for each crop. Photosynthetic photon flux densities of 0, 1, and 5 μmol·m-2.s-1 were combined with temperatures of 0.0, 2.5, 5.0, 7.5, 10.0, and 12.5C to create 18 storage environments. Sample plants were removed from each treatment at 1-week intervals for 6 weeks, and were forced into flower. In all four species, temperatures of 0.0 and 2.5C caused chilling injury and then death as plants were stored for progressively longer periods. Storage at 0.0 and 2.5C also delayed flowering when chilling injury was not severe enough to cause death. In general, plants stored better in the light than in darkness. Darkness tended to limit the time seedlings could be stored, but for each crop, the addition of just 1 μmol·m-2.s-1 extended the storage durations to 6 weeks at one or more temperatures. Storage of all four species was possible for 6 weeks, but there were significant variations between the temperatures and storage durations each species could tolerate. Optimal temperatures were 5-7.5C for begonia, 5C for marigold, and 7.5C for salvia and ageratum.
FEASIBILITY OF GROWING GUAVA IN MIDDLE GEORGIA
Authors: Yadava Umedi L.
Published: February 2019

Seeds of a pink flesh test line of guava (Psidium guajava L.) from India, were germinated in a greenhouse. In April 1988, 6-month-old guava seedlings were set 3 m apart in a field row while an equal number of plants in 15 liter containers, were held in the greenhouse. The field plants were more vigorous than those held in the greenhouse. However, the field plants could not survive severe winter conditions outdoors and were totally destroyed by winter freezes of 1989-90. In spring 1990, the plants held in greenhouse were transplanted in the field under a 6-mil polyethylene protective cover where they flowered during February-April 1991. Trees were productive with 52 fruits per tree, most of which reached maturity without a drop or pest problems. Fruit ripening on trees began in late August 1991. Values for such parameters as fruit weight, height from blossom end to stem end, circumference and volume were 269.3 g (±10.6), 7.3 cm (±0.1), (25.6 cm (±0.3), and 279.7 ml (±11.4), respectively. Actual values ranged from 117 to 597 g, 5.5 to 10.1 cm, 19.3 to 33.2 cm, and 131 to 639 ml, respectively. Tree-ripe fruits had pink tinge on yellow-green skin and pink colored thick flesh had mild aroma and good flavor. Guava can be successful in Middle Georgia with proper care for cold protection.
Kiwifruit storage performance is related to position on vine, fruit weight and fruit mineral content.
Authors: Mowatt Craig M , Banks Nigel H , Hewett Errol W
Published: February 2019

Positions of every individual kiwifruit were mapped on each of five eight-year-old vines on a T-bar training system before harvest. The proportion of excessively soft kiwifruit (< 1.0 kgf penetrometer reading at 20C) after 130 days coolstorage at 0C on individual vines ranged from 7 to 45%. Fruit at the distal ends of fruiting canes were significantly heavier and firmer (mean wgt 108.5 gms, mean firmness 1.22 kgf) than fruit closest to the main leader (105.6 gms, 1.18 kgf). Conversely, for multiple clusters, fruit on spurs adjacent to the fruiting cane were heavier than those at the terminal end (109.9 and 103.8 gms), respectively, though firmness of these fruit did not differ significantly. The firmest fruit had less nitrogen, less potassium, less phosphorus and more calcium than the soft fruit. Potential means by which this information could be used to improve fruit storage quality will be discussed.
HORTICULTURAL PROPAGATION TECHNIQUES APPLIED TO SOFTWOOD CUTTINGS OF JUVENILE LOBLOLLY PINE (PINUS TAEDA L.), A SOUTHERN FOREST SPECIES
Authors: Wise Farrell C. , Greenwood Laura L. , Rowe D. Bradley
Published: February 2019

Clonal propagation of recalcitrant conifers like loblolly pine depends on producing juvenile cuttings on hedges sheared several times annually. Although dormant cuttings root well, it will be economically important to also root softwood shoots produced between shearings. Several variables were therefore evaluated in a factorial experiment to enhance rooting and handling of summer cuttings. Rooting percentages were equivalent for 3 media after a 5-week hardening period (56% overall), but open flats of 1 perlite:1 vermiculite induced larger root systems at the end of rooting and hardening phases. Extending the rooting period from 10 to 14 weeks increased rooting from about 45% to 58% by the end of hardening. Primary root length per cutting increased 12-63% during hardening, depending on medium. After transplanting, overwintering survival was 98%. Foam rooting wedges produced smallest root systems, and resulting plants were consistently shortest through the following growing season. Weekly applications of soluble fertilizer during the last 6 weeks of rooting did not improve rooting or subsequent growth
PHOTOPERIOD AND TEMPERATURE INFLUENCES ON COMMON BACTERIAL BLIGHT DISEASE IN DRY BEANS AND IMPLICATIONS
Authors: Coyne D. P. , Arnaud-Santana E. , Beaver J. , Zaiter H.
Published: February 2019

Some dry bean lines (L) Phaseolus vulgaris resistant (R) (compatible reaction) to Xanthomonas campestris var. phaseoli (Xpc) developed in the temperate zone express susceptibility (S) in the field in the tropics and tropical lines (S) express moderate R in the temperate zone. There is only limited information on the influence of P on Xpc reaction in dry beans. Experiments were conducted in growth chambers (GC) and in the field (NE, Dominican Republic, Puerto Rico) to investigate the influence of P and P × temperature (T) on the reaction of L to Xpc. A split-plot design was used with T as the main-plots and P and L as sub-plots in the GC experiment and with P as main-plots and L as sub-plots in the field experiments. The disease reactions were more severe on L under short P and under higher T than under shorter P and lower T. No interactions were detected among these treatments. PC-50 showed moderate R, delayed flowering, flower bud abortion, and increased branching under long P (field, NE). These results have implications for breeders in the evaluation of field R of L from different latitudes and for their value in breeding.
Orchid cut flower production in Singapore and neighbouring countries
Authors: Hew C.S.
Published: February 2019

Orchid cut flower industry has contributed substantially to the economy of Singapore, Thailand, Malaysia and other Asean countries. Singapore exports US$13 million dollar worth of orchid cut flower in 1990 and Thailand's export was at least 3 to 4 times higher. Germany and Japan are the major markets for tropical orchid cut flowers. Economically important orchid genera are Aranda, Dendrobium, Mokara, Oncidium and Vanda. This paper will review the agronomic practices in orchid cultivation, the current status and development of orchid industry and the research and development made towards the improvement of the orchid industry in Asean countries.
MODELING CHILLING INFLUENCE ON CUMULATIVE FLOWERING OF RABBITEYE BLUEBERRY
Authors: Bridges D.C. , NeSmith D.S.
Published: February 2019

A Weibull distribution function was used to develop a model for estimating cumulative flowering and the distribution of flowers of `Tifblue' rabbiteye blueberry (Vaccinium ashei Reade) as a function of growing degree days (GDD) after chilling for chill hours ranging from 300 to 1200. Controlled chilling and flowering conditions were imposed on blueberry plants to obtain data for model development. Once developed the model was validated using independent data sets which were available in the literature. Given information concerning chilling and historical GDD, the model can be used to predict the onset of flowering, cumulative flowering, total number of flowers, and flower frequency at discrete intervals. It is expected that the techniques developed will be applicable to a range of fruit species in which chilling influences flowering habit.
THE USE OF A TESTER CLONE FOR SOUR CHERRY GERMPLASM EVALUATION
Authors: Iezzoni Amy
Published: February 2019

Progress in sour cherry breeding in the U.S. is severely hampered by the limited germplasm available. Importing Prunus germplasm into the U.S. as budwood from the center of diversity in Eastern Europe, is impractical because of the lengthy quarantine period required. Instead it is proposed that pollen collection and the use of a tester clone would be the most efficient way to import and use sour cherry germplasm. Sour cherry pollen can be imported and used directly without a quarantine period. When the pollen is used in crosses with an appropriate tester clone, the breeding value of the germplasm can be assessed relatively easily because both parents are known as opposed to one parent as is the case with open-pollinated seed. Once a germplasm source has been identified as having a desired breeding value, pollen can again be imported or requested from the Plant Introduction Station where presumably the clone is still in quarantine, and used in routine breeding crosses. For a clone to be a good tester, it must induce precocity in the progeny and behave in a recessive manner for traits of importance. Data is presented to illustrate the use of the sour cherry cultivar English Morello as a tester clone for sour cherry germplasm evaluation.
THE ABNORMAL MEIOSIS OF PMC IN FEICHENG PEACH
Authors: Shi Yinping , Wang Qiangsheng
Published: February 2019

Feicheng peach is a famous cultivar of Prunus persica. Not only the fruits which are giant with superfine flavour are out of ordinary, but also the meiotic behaviour of PMC is abnormal.

About 40–100% of the anthers were found to have a few binucleate microsporocytes in company with normal single ones. The binucleate microsporocyte is about 2 times as large as single microsporocyte. It is neither an end product of cytomixis nor a giant microsporocyte and is characterized by having two nuclei in a common elliptical cell wall. The two protoplasts divide independently and consequently to give octads instead of tetrads.

Poly—nuclei and poly—nucleoli were observed in some microsporocytes at prophase I. At telophase I. II. nearly all the microsporocytes contained poly—nuclei and poly—nucleoli. This is also true in some of the microspores. Both the number and the size of poly-nuclei in each microsporocyte and of poly—nucleoli in each nucleus were diverse.

At telophase II, about 74% of single microsporocytes produced tetrads, and the rest formed diads. triads, unequal tetrads, pentads, hexads, heptads or octads. The microspores formed were unequal in size except those formed from diads. Most binucleate microsporocytes produced octads. and a few formed hexads, heptads. enneads or decads. Their microspores are nearly equal in size.
VARIABILITY AND SELECTION IN AN INTERSPECIFIC HYBRID POPULATION OF PACHYRRHIZUS EROSUS X P. AHIPA (YAM BEAN)
Authors: Hartmann Richard W.
Published: February 2019

F3 seeds from a cross of P. erosus (indeterminate, daylength sensitive) X P. ahipa (determinate, daylength insensitive) were received from M. Sorensen of the Royal Veterinary and Agricultural University in Copenhagen, Denmark and sown in Hawaii in April, 1989 to increase the seed. The F4 seed were planted in March, 1990 and in October, 1990 (the normal time). All F4 progeny included both bush and vine plants in the summer planting, with more bush plants in the progeny of F3 bushes than vines. Likewise, the progeny of earlier-flowering F3 plants had a higher percentage of plants in flower in June than progeny of later-flowering ones. Root sizes and shapes were variable. The F4 progenies of the lines with the highest percentage of bushes and early-flowering plants were regrown in the summer of 1991 and selected for summer-flowering bush plants with acceptable root size. The selections were then grown in the winter of 1991 to test for performance during the normal growing season.
EFFECTS OF CROP LOAD AND LOW-SOIL MOISTURE ON PHYSIOLOGY AND ROOT DYNAMICS IN SEYVAL GRAPEVINES.
Authors: McLean M. , Howell G.S. , Smucker A.J.M.
Published: February 2019

An experiment was conducted to evaluate interrelationships between differing crop loads and water stress on physiology and root dynamics of 3 year old Seyval grapevines grafted to 5-BB, Seyval and Seyval own-rooted stock grown under a rain exclusion shelter. Treatments were: 1) cropping level, either 0 (defruited) or 6 clusters/vine (heavily cropped) and 2) irrigation level, either 2.5 (stress) or 10 liters (control) of water/plant/week. Vines had significantly different root dynamics in regards to crop load, water status and rootstock. Water stressed vines had significantly fewer and smaller leaves (area cm 2 lighter trunk weights (g) and shorter shoot length compared to control vines. Heavily cropped vines had significantly fewer mature nodes, shorter shoot growth and higher bud mortality (winter injury) compared to defruited vines.
ABA AS A ROOT SIGNAL IN GRAPEVINES UNDER WATER STRESS
Authors: Peterlunger E. , Marangoni B.
Published: February 2019

ABA implication in root signals of water stress has been suggested by several authors. To verify this hypothesis in grapevines, this experiment has been carried out. One-year-old own rooted cuttings of grapevine cultivar Cabernet Sauvignon were exposed to water stress. After three months of growth, water was completely withdrawn for nine days, till the plants reached the wilting point. The plants were then rewatered. During the whole period, root hydraulic conductivity was measured with a pressure bomb; xylem sap samples were collected, as well as leaf and root samples. ABA concentration in these samples was measured using Radio Immuno Assay with DBPA1, a monoclonal antibody for ABA. The concentration of xylem sap ABA was 68.2 mg m-3 at the start of the experiment. After eight days of stress it was 1863.6 mg m-3, 27 × higher. On the ninth day the plants were rewatered, and the xylem sap ABA decreased at 100.2 mg m-3, keeping this level for eight more days. Leaf ABA showed high levels of this inhibitor, with a peak in correspondence with the maximum stress. A similar behaviour was attained by roots. In grapevine, ABA seems to be involved in a water stress root signal directed to the canopy.
UTILITY OF DIF TO REGULATE VEGETABLE TRANSPLANT STEM ELONGATION
Authors: Erwin John T.
Published: February 2019

Seedling stem elongation increased as the difference (DIF) between day (DT) and night (NT) temperatures increased from 10 to 26C (DIF=DT-NT). Stem elongation was primarily dependent on DIF on all crops studied except spring bulb crops. Internode lengths decreased in tomato (68%), watermelon (80%), squash (32%), sweet corn (68%) and snap bean (26%) as the difference between day and night temperatures decreased 12 degrees (C). Cucumber internode length decreased by 84% as DIF decreased 16 degrees (C). The ratio of male to female cucumber flowers decreased from 14 to 1, as DIF decreased 12 degrees (C) from 23 DT/17 NT to 17 DT/26 NT. Stem elongation was very sensitive to cool temperatures during the first 3 hours of the morning. Stem elongation was almost the same if the seedlings were cooled for the first 3 hours of the day versus cooling the plants all day. The interactions between temperature on stem elongation and light quantity and quality, and photoperiod will be discussed. Application of DIF in both northern and southern greenhouses will also be discussed.
CYTOKININ DIPS AND SUCROSE HOLDING SOLUTIONS INCREASE THE POSTHARVEST LONGEVITY OF `NITTA' ANTHURIUMS AND PINK GINGERS.
Authors: Whittaker Jane , Nell Terril A. , Barrett James E. , Sheehan Thomas J.
Published: February 2019

The effect of postharvest dips on the longevity of Anthurium andraenum cultivar Nitta and Alpinia purpurata was evaluated. The inflorescences were dipped in a 200 ppm benzyladenine (BA) solution, an antitranspirant, or water for 10 minutes. After dipping, anthuriums were placed directly in water and gingers were placed in either water or a 2% sucrose solution and placed in interior conditions (10 μmol m-2s-1 for 12 hr/day, 21±2C). Ginger longevity was increased by 10 days or more by the sucrose solution. The greatest longevity of gingers was obtained when dipped in either BA or the antitranspirant and held in the sucrose solution. Anthurium longevity increased 10 days when dipped in BA, while the other treatments had little effect.
ENGINEERING FOR MICROPROPAGATION OF SUGARCANE
Authors: Walker Paul N. , Harris Joan P. , Gautz Loren D.
Published: February 2019

Four engineering studies on optimization of sugarcane micropropagation are summarized. The optimum environmental conditions based on the cost of production were found to be with two medium changes per multiplication period, 6 initial shoots per vessel and a photosynthetic photon flux of 200 μmol/m2s even though greater production was obtained for more light, fewer shoots per vessel and more medium changes. A cost model for comparing production treatments under steady state production and a linear programming model for unsteady state production are discussed. Preliminary results on mechanization of the transfer process are also presented.
EFFECT OF EXPLANTS AND GROWTH REGULATORS ON SOMATIC EMBRYO-GENESIS AND ADVENTITIOUS ORGANOGENESIS IN CAPSICUM ANNUUM
Authors: Park Hyo-Geur. , Choi Kyung-Young , Lee Do-Hyun
Published: February 2019

Hot pepper is the most important vegetable in Korea in terms of both acreage and product value. Morphogenic response in tissue culture of hot pepper varied greatly with explant source and growth regulators. Somatic enbryogenesis, which we believe had not been reported yet, was only induced from 5-month-old callus derived from anther culture. Embryogenic callus was solely observed in the MS medium supplemented with 2 mg/l of NAA and 2 mg/l of BA. Better somatic embryogenesis and plant regeneration was observed on hormone free medium. Adventitious organogenesis was well induced from both hypocotyl and cotyledon. Polarity of explant for shoot regeneration was observed. Success rate of regeneration has been continuously improved mainly due to combinations of growth regulators. The best combination so far was 2 mg/l of zeatin and 1 mg/l of IAA, resulting in 92% of regeneration from cotyledon explant.
HYDROGEN CYANAMIDE ALLOWS EARLY HARVESTING OF PECAN
Authors: Wood Bruce W.
Published: February 2019

Pecan growers often receive substantially higher prices for nuts if they can be marketed early in the harvest season, sometime doubling their profit as a result. Time of nut ripening (shuck dehiscence) is the primary limiting factor to the realization of early harvesting. It is now possible to advance shuck dehiscence by 10 days or more using hydrogen cyanamide (formulated as Dormex). A three year study using young 'Cheyenne' trees (6th leaf) indicated that budbreak, flowering, and shuck dehiscence could be advanced when treated with hydrogen cyanamide during the winter dormant season. The degree of advancement varied with the application date and concentration utilized. Results we most desirable when treatments were applied about 60 days before budbreak and application was at the 2% and 4% (480 and 960mM) levels. Hydrogen cyanamide had no detectable adverse effects on any growth, quality or production parameter.
DELAYED COSTS OF REPRODUCTION, DEFOLIATION, AND SHADING IN PISTACIA VERA L. CV. KERMAN: BUD ABSCISSION AND DRY WEIGHT ALLOCATION TO BUDS, LEAVES, CURRENT AND PREVIOUS-YEAR SHOOTS
Authors: Nzima Muntubani D. S. , Martin George C. , Nishijima Chic
Published: February 2019

Trees that fruited during 1990 retained 67.3% of the inflorescence buds produced per branch in 1991 compared to 63.1% for trees that were defoliated immediately after harvest in 1990 and 21.3% by trees that were fruiting in 1991. Shading reduced bud retention similar to fruiting.

Defoliation after nut harvest accentuated the delayed costs of reproduction caused by previous season's fruiting whereas shading produced significantly greater immediate costs. Shading effects on the allocation of carbon to buds, leaves and shoots were similar to those of fruiting. Leaf net photosynthesis under shade conditions was reduced to 14.27% of control trees and this led to a significant reduction in the relative growth rates of all the organs surveyed.
CYTOHISTOLOGY OF A 2–2–4 TYPE SPORT IN BARTLETT PEAR (Pyrus Communis)
Authors: Wang Qiangsheng , Shi Yinping , Sun Qingrong , Yin Yongsheng
Published: February 2019

In the 1980' s, a Bartlett pear giant fruit sport was found in Pingdu, Shandong. The characteristics of mutation are larger fruit, thicker branch, shorter internode and much more spur. By grafting propagation, the clones began to bear fruit in 1990, and maintain the characteristics of variable mother plant.

From microspore formation to blossom and spreading pollen, the cytohistological observation of sport flowering organs indicates: in every phase of pollen development, the size of florets, anthers and pollen grains are similar to CK; their pollen types both belong to tricolporat, pollen grains are nearly equal in size. This indicates that sport sporogenous tissue do not mutate. The observation of shoot apex sections showes: for CK, the cells of three histogenic layers range regularly; the size of cells, nuclei, and nucleoli among LI, LII, LIII are similar. For sport, the cells of LI, LII are no difference from CK, but in LIII and inner tissue, cells, nuclei, nucleoli all become larger clearly. This indicates LIII had mutated. So this sport is a 2–2–4 type chimera.
A MECHANISM FOR TRANSPORT OF SUBSTANCES BY TEMPERATURE-INDUCED PRESSURE GRADIENTS
Authors: Corey Kenneth A. , Tan Zhi Yi
Published: February 2019

Diurnal changes in air and soil temperatures lead to temperature gradients between air and soil, between roots and shoots, and within plant organs. In response to these gradients, fluctuations in gas pressures may develop in organs that are resistant to exchange of gases. These fluctuations may regulate mass flow of gases or solutions within plants. Patterns of diurnal temperature changes were generated to illustrate temperature gradients between roots and shoots. Experimental confirmation of pressure changes induced by temperature differences between roots and shoots were measured with water manometers attached to stumps of detopped tomato plants. When roots were maintained 8 C lower than shoots, internal pressure decreased by 22 cm H2O. Reversing the direction of the temperature gradient led to an approximately equal and opposite pressure change and to sap movement. These results support a hypothesis that internal pressure gradients resulting from temperature gradients contribute to transport of substances in plants.
FLOWER ORIENTATION INFLUENCES OVARY TEMPERATURE DURING FROST IN PEACH
Authors: Lu Shaoli , Rieger Mark , Duemmel Michael J.
Published: February 2019

Ovary temperatures of upward and downward facing flowers of `Junegold' Peach (Prunus persica (L.) Batsch) were measured on 5 nights in March 1991 to determine whether differential survival of ovaries following frost was related to flower orientation. Flowering twigs were removed from mature trees and positioned horizontally ≈ 1.5 m above ground level prior to occurrence of low temperatures (0-5C). Thermocouples were inserted through the hypanthium to contact ovaries of 10 upward and 10 downward facing flowers, and temperature and meteorological data were logged every five minutes. Under clear, calm conditions, temperature of upward facing flowers averaged 0.33C lower than that of downward facing flowers during the coldest period of the night, with maximal differences of 0.77C. Under cloudy, calm conditions, temperature differences between upward and downward facing flowers were less frequently observed and lower in magnitude (0.08 - 0.15C). Under windy conditions (>2.5 m/s), no temperature difference between upward and downward facing flowers occurred, despite strongly negative net radiation. Based on known values of ovary cold tolerance, it is concluded that differences in survival of Up to 38% could occur due to flower orientation when air temperature reaches critical values.
FALL, SPLIT, AND TANK-MIX APPLICATION METHODS AS ALTERNATIVES TO SPRING PREEMERGENT HERBICIDE APPLICATION
Authors: Kaps Martin L. , Odneal Marilyn B.
Published: February 2019

Preemergent herbicides were applied to vineyards in the southcentral Missouri Ozark region. These were applied at full label rate in the fall or in the spring, at half rate in the fall and again in the spring, and as tank-mixes in the spring. Days of acceptable annual weed control (30% or less cover) beyond the untreated control were determined for these application methods over three years. The fall applications were effective at controlling winter annual weeds and early summer annual weed growth the following season. By mid summer the fall applied preemergents lost residual activity. Splitting the label rate between fall and spring was no better than a full rate spring application at increasing the days of acceptable summer annual weed control. Single preemergent spring application performed as well as tank-mixes.
ENDOPHYTIC AND EPIPHYTIC GROWTH OF BIOLUMINESCENT XANTHOMONAS CAMPESTRIS PV. CAMPESTRIS IN AND ON RESISTANT AND SUSCEPTIBLE HOST PLANTS AND THEIR ENVIRONMENT.
Authors: Dane Fenny , Shaw Joe
Published: February 2019

The movement of genetically engineered, bioluminescent, Xanthomonas campestris pv campestris, causal agent of black rot in crucifers, was followed after wound or mist inoculation of susceptible and resistant host plants. Wound inoculation resulted in higher bacterial population levels in susceptible (Perfect Ball) as compared to resistant (Hancock) cabbage plants. More leaves became infected in the susceptible host and peak levels were reached after 4-8 days, but after 10-12 days in the resistant plants. Mist inoculation resulted in high levels of bioluminescent Xcc after 11-15 days in susceptible tissues only, unless entry was gained through damaged tissue of the resistant plant. In the field environment, Xcc was found endophytically after mist inoculation in susceptible cabbage only, but found to grow epiphytically for as long as 2 1/2 months to the same degree on resistant and susceptible host plants. Dispersal of the bacterium was limited and survival in the soil environment found to last for four months.