bluuebunny/crossref_metadata_2025 huggingface dataset:
516 PB 450 USE OF A BOUNCEMETER TO SHOW VARIETAL DIFFERENCES IN PEACH FRUIT QUALITY DURING RIPENING
Authors: Okie W.R.
Published: February 2019

Peach breeders need rapid, non-destructive methods to rate fruit quality changes after picking in order to select genotypes that can be delivered to the consumer with the maximum quality. Changes in ground color and firmness over time can be quantified by use of a bouncemeter (which measures coefficient of restitution) in conjunction with a colormeter. During 1991 and 1992, the ripening patterns of over 100 peach and nectarine varieties and selections were measured, allowing comparisons between different genotypes. Ten fruit, picked when firm ripe, were measured both before and after storage for 5 days at 5°C followed by 2 days at 20°C. Soluble solids (%) for each fruit were then measured with a refractometer, followed by determination of titratable acidity on 2 pooled samples. In general ground color changed from green to yellow and firmness decreased over time, but genotypes varied widely in the relationship of ground color and firmness. There also appeared to be differences in rates of change of these parameters.
520 PB 480 USE OF TYVEK HOUSEWRAP FOR POLLINATION BAGS IN BREEDING OF HAZELNUT
Authors: Smith David C , Mehienbacher Shawn A.
Published: February 2019

Tyvek housewrap (Du Pont, Wilmington, Delaware), an air-infiltration barrier for use in house construction, has been put to a novel use for making pollination bags for breeding hazelnuts (Corylus avellana L.). Bagged flowers are used in making crosses and incompatiblity testing and remain receptive for up to 3 months. Tyvek has outperformed paper and plastic materials we have tried in terms of durability and cost. Tyvek is a spun-bonded, nondirectionally oriented film of highdensity polyethylene fibers that is permeable to water vapor and air, but is water resistant and pollen-proof, and can be made into bags of any size needed.
529 PB 525 DETERMINING RESISTANCE IN STRAWBERRY TO ANTHRACNOSE USING TOXINS PRODUCED IN FUNGUS CULTURE
Authors: Maas John L. , Galletta Gene J. , Smith Barbara J.
Published: February 2019

We have determined in tests conducted both at Beltsville and Poplarville that several strawberry isolates of Colletotrichum acutatum, C. gloeosporioides and C. fragariae produce toxin-like compounds in culture. Crude culture filtrates (CFI elicited general and specific responses in tomato and strawberry plants. Tomato plants initially were used because they are highly responsive to toxins in general, whereas the reaction of strawberry plants apparently is greatly affected by environmental and nutritional growing conditions of the test plant. Toxin symptoms included leaf chlorosis and wilting, leaf midvein darkening, and plant death when CF was applied to leaves or if seedlings or petioles were immersed into CF. Juvenile tissues appear to be more susceptible to the effects of the toxins than mature tissue. No differences in response to culture filtrates were apparent among those from the Colletotrichum isolates. The putative toxins appear to act differentially with susceptible or resistant strawberry germplasm.
532 PB 008 DEVELOPMENT OF ROOT RESTRICTION STRESS IN WATERMELON TRANSPLANTS
Authors: Liu Aimin , Latimer Joyce G.
Published: February 2019

Seeds of `Mirage' and `Starbrite' watermelon [Citrullus lanatus (Thunb.) Matsum. and Nakai] were sown in TODD planter flats with root cell volumes of 20, 28, 39, 49, or 83 cm3. Plants were harvested for growth measurement at 5, 10, 15 and 20 days after seeding (DAS). Data were regressed over root cell volume for each harvest date. The effect of root volume restriction (RVR) was determined by comparing the slopes of the regression lines. All measurements of growth increased with increasing root volume at each harvest date. Generally, the slopes of all regression lines increased with each successive harvest, i.e., plant growth was limited more in the smaller root volumes than in larger volumes at each successive harvest. The greatest increase in the slopes of the regression lines occurred between 10 and 15 DAS for most measurements of both cultivars. This indicates that RVR became significantly more limiting to seedling growth after 10 DAS which corresponded to the second to third true-leaf stage.
533 PB 011 SCREENING OF POLYETHYLENE AND ORGANIC MULCHING FILMS FOR USE IN MELON PRODUCTION IN THE LOWER RIO GRANDE VALLEY
Authors: Brandenberger L.P. , Wiedenfeld R.P.
Published: February 2019

Bare soil, 13 different polyethylene mulching films, and K-Mulch kenaf paper film were compared to one another for use in early spring production of cantaloupe melons. The mulching treatments were applied to the top of raised beds spaced 200 cm apart in late January and seed of the cantaloupe variety Cruiser were planted in early February. Treatments were replicated five times in a complete randomized block design. Plots were irrigated throughout the season utilizing a drip irrigation system. Crop responses to mulches throughout the growing season were determined by measuring vine growth, fruit yield, Fruit quality and earliness. Mulch tensile strength was determined throughout the season, and ease of cleanup and disposal were evaluated after the growing season. Differences were recorded for treatments particularly regarding ease of cleanup.
537 PB 043 ROWCOVER AND BLACK PLASTIC MULCH EFFECTS ON TOMATO PRODUCTIONS
Authors: Rubeiz Ibrahim G. , Freiwat Marlene M.
Published: February 2019

Tomato cv. Alwadi were grown under floating rowcover, black plastic mulch, mulch plus rowcover, or no protection i.e. control, for studying the effect on yield in terms of earliness, total yield and average fruit size. Early yield was significantly increased by the mulch treatment while the rowcover treatment yielded the least (P < 0.05). Total yield was increased by the mulch and mulch plus rowcover treatments, while the rowover and control treatments yielded the least (P < 0.05). Soil temperature at 10 cm depth varied between 1° to 2°C only under the different treatments. Air temperature under the rowcover exceeded 35 to 40°C on many days, hence causing fruit setting problems and resulting in reduced early yield under the rowcover. Our results show that earliness is enhanced by black plastic mulch, while the rowcover alone can have a negative effect on yield. Time of rowcover removal above the mulch warrants further research.
550 PB 122 SOIL MOISTURE REQUIREMENTS FOR OPTIMAL GROWTH OF VEGETABLE AMARANTH
Authors: Singh Bharat P. , Whitehead Wayne F.
Published: February 2019

In literature, amaranth is described as a stress tolerant crop. However, most of the investigations have been concerned with the production of grain crop. The soil moisture regime which promotes maximum vegetative growth is yet to be established. During 1993, the vegetative growth response of amaranth to different soil moisture levels was determined in a greenhouse study. Amaranth cultivar Hin Choy was grown in Dothan sandy loam soil at four soil moisture levels of 6.0, 9.0, 12.0 and 14.0% (w/w) in a randomized complete block experiment with ten replications. Plant height, leaf number, leaf area, leaf fresh and dry weight, stem fresh and dry weight, root fresh and dry weight, leaf-stem ratio, and stem fresh and dry weight were recorded. All parameters gained significantly with each increment in the soil moisture level up to 12%. There was no difference in plant response between 12% and 14% soil moisture. The study indicated that for optimum vegetative growth, amaranth requires a moisture stress free soil environment.
553 PB342 COLD RESISTANCE OF `ANJOU', `BARTLETT' AND `BOSC' PEAR TREES
Authors: Ketchie Delmer O. , Kammereck R.
Published: February 2019

Samples of current season shoots of Anjou, Bartlett and Bosc pears were collected throughout the year during 1990, `91 and `92. Differential thermal analysis (DTA) and vital staining with triphenyltetrazolium chloride (TTC) were used at the sampling times to determine freeze resistance. Freezing tests were conducted on greenhouse-grown trees. Temperatures to freeze the trees were predetermined by DTA. After freezing TTC staining, acid fuchsin test and growth were used to determine survival. All three varieties began to acclimate after terminal growth ceased in late June until October. Bartlett and Anjou obtained about -25°C resistance by this time and Bose about -23°C. After frost began, Anjou and Bartlett gained an additional resistance to -33°C and Bose to -28°C. Trees frozen artificially at -27°C had limited growth but did leaf out only to die a month later. Trees frozen at -33°C never leafed out Bartlett trees at -27°C looked better than Anjou and Bose trees but died also.
558 PB 377 SALINITY AND LEAF GAS-EXCHANGE OF ANNONA SOUAMOSA
Authors: Marler Thomas E. , Zozor Yasmina
Published: February 2019

Leaf gas-exchange responses of A. souamosa seedlings to salinity were studied in sand culture in a series of glasshouse experiments. Trees were irrigated with a complete nutrient solution as the control, or with this solution amended to 3 or 6 dS/m with sea salt. Inhibition of net CO2 assimilation, stomatal conductance of CO2, and transpiration was apparent 14 days after treatments were imposed, and continued to decline until day 30 to 35. The diurnal pattern of leaf gas exchange was not altered by salinity. Salinity reduced CO2, light energy, and water use efficiencies. Dark respiration and internal partial pressure of CO2 were unaffected by salinity stress. Results indicated that substrate salinity inhibited photosynthesis of A. souamosa via limitations on mesophyll capacity for CO2 assimilation and had little effect on gas phase limitations.
566 PB 003 HEAT EFFECTS ON ROOTING SOFTWOOD CUTTINGS OF `AUTUMN FLAME' AND `INDIAN SUMMER' RED MAPLE
Authors: Zhang Hongyi , Graves William R. , Townsend Alden M.
Published: February 2019

Single-node cuttings of `Autumn Flame' and `Indian Summer' red maple (Acer rubrum L. and A. × freemanii E. Murray) were placed in subirrigated perlite that was kept at 29, 33, or 36 C at the cut ends for 3 weeks. Number and mass of roots and pigment quality and transpiration of leaves were greater for `Autumn Flame' than `Indian Summer' and decreased with increasing temperature for both cultivars. Rooting percentage at 29, 33, and 36 C was 75, 75, and 25 for `Autumn Flame' and 13, 13, and 0 for `Indian Summer'. Earlier work has shown > 90% of cuttings of both cultivars root at ≈ 22 C, and plants of `Autumn Flame' are more heat resistant than those of `Indian Summer'. Results of this experiment suggest the effect of heat on rooting of cuttings might be used to predict genotypic differences in heat resistance of whole plants.
578 PB 059 IN VITRO ROOTING OF PYRUS GERMPLASM
Authors: Reed Barbara M.
Published: February 2019

Cultures of 49 Pyrus species and cultivars and one Pyronia (Pyrus × Cydonia hybrid) selection were screened in vitro to determine a rooting method suitable for a wide range of germplasm. Auxin treatment was required for rooting in most cases. Eighteen of the 50 accessions rooted with a 15 sec. 10 mM indole-3-butyric acid (IBA) dip followed by growth on medium with no growth regulators (NCR). Medium with 10 μM IBA for one week followed by NCR medium produced 12 rooted accessions, but NCR medium alone produced little or no rooting. A 15 sec. dip in 10 mM naphthaleneacetic acid (NAA) followed by NCR medium was tested on 29 accessions which rooted poorly on the other three treatments. Twice as many (28%) rooted on NAA as on either IBA treatment (14% each). Additional treatments combining IBA with darkness or higher temperature were also tested and were successful for some cultivars. P. calleryana, P. koehnei, P. pashia, P. hondoensis, P. ussuriensis, P. betulifolia, P. regelii, P. pyrifolia hybrid cv. Shinseiki and the Pyronia selection failed to root. Twenty two of the 32 P. communis cultivars rooted on at least one treatment.
586 PB 123 AXILLARY SHOOT REGENERATION IN CHINKAPIN OAK
Authors: Vyapari Sudeep , Khatamian Houchang
Published: February 2019

Surface disinfested nodal and shoot-tip sections of chinkapin oak (Quercus muehlenbergii Engelm.), obtained from adult or juvenile source, when cultured on WFM supplemented with BA or kinetin (1.0 -5.0 mg l-1) produced greater number of axillary shoots per explant and shoot lengths than MS medium. Nodal and shoot-tip explants cultured in WPM containing cytokinins, BA or kinetin (0.1 - 5.0 mg l“) resulted in greater number of axillary shoots than media containing auxins, 2,4-D or NAA (1.0 - 5.0 mg l-1). In vitro grown shoot explants cultured in WFM shoot multiplication medium containing thidiazuron did not produce axillary shoots. Microshoots when cultured in WFM plus NAA or IBA (0.1 -2.0 mg l-1), or subjected to IBA (0.5 mg l-1) pulse treatment (0, 5, 10 or 15 min.) did not root.
588 PB 129 IN VITRO MULTIPLICATION OF STEWARTIA MALACODENDRON L., AN ENDANGERED WOODY SPECIES
Authors: Gillis Murdock Ray , Kane Michael E.
Published: February 2019

Stewartia malacodendron L. (silky camellia), a small deciduous tree bearing showy flowers, has potential as a landscape plant. Propagation problems, limited availability and consequent high unit cost have slowed its acceptance as a landscape plant. Given its potential value as a landscape plant, studies were initiated to define a micropropagation protocol. Surface sterilized shoot tips and nodal explants from two-year-old container grown seedlings were established on Woody Plant Medium supplemented with 4.44 μM benzyladenine (BA) and solidified with 0.8% TC® Agar. Sustained growth of subcultured shoot tips and nodal segments required the addition of 8-15 μM gibberellic acid (GA3) to the medium. Regenerated shoots were 3 - 5 cm long, unbranched and typically consisted of three subdivisions. Effects of cytokinin type (BA, 2iP or kinetin) and concentration (0-25 μM) with factorial combinations of GA3 (0-30 μM) on shoot multiplication, elongation and diameter were determined after a 28 day culture period. Moderate GA, levels (10 & 20 μM) in combination with 2.5 μM BA yielded the highest quality microcuttings.
601 PB 211 QUANTIFYING YIELD LIMITATIONS IN PEACH TREES
Authors: DeJong Ted M.
Published: February 2019

Previous research using relative growth rate models indicates that under normal cropping conditions peach fruit growth and yield is alternately source and sink limited during different phases of fruit growth. An experiment was designed to test this concept on whole trees in the field. Shortly after bloom central leader trees of `Spring Lady' and `Cal Red' peaches, were thinned to various crop loads ranging from -50 to -400 fruit per tree. At specific intervals trees representing the full range of crop loads were harvested to determine mean individual fruit weight/total crop weight relationships for whole trees. Then, assuming that fruit on low cropped trees grew at their maximum potential growth rate (sink demand) and that total crop growth on unthinned trees represented the maximum dry matter available for fruit growth (source supply), the relative source and sink limitation between each harvest interval was calculated. With `Cal Red', fruit growth appeared to be primarily source limited early and late in the season but primarily sink limited during the mid-period (Stage II) of fruit growth. At normal commercial crop loads, `Spring Lady' was less source limited than `Cal Red'.
619 PB 325 Respiration as an indicator of health in excised, dormant vegetative apple buds subjected to cryopreservation treatments
Authors: Towill L.E. , Blackman S.A.
Published: February 2019

cryopreservation of dormant, vegetative apple buds at the National Seed Storage Laboratory is used to maintain a base collection for germplasm held in the National Clonal Germplasm Repository for apple and grape, Geneva, NY, and is performed by a method previously reported1. Growth of buds after grafting is now used to test for survival after exposure to and storage at very low temperatures (ca.-160°C). We are interested in determining if measures of respiration can be used to assess 1. the status of buds and bark used for preservation, 2. survival after different treatments related to cryopreservation, and 3. the extent of sublethal injury after treatments. A Licor 6252 CO2 analyzer was used to measure respiration. Reproducible measurements of respiration required at least 2-3 buds. Buds from winter harvested twigs (ca 45-48% moisture content) that were briefly warmed to room temperature respired at a rate of 34 umoles CO2 g-1 (dw) hr-1. Survival of buds is enhanced if twigs are dried prior to cooling. We found such treatments reduced respiration over non-dried controls. Respiration increased as the bud was rehydrated. Buds from dried twigs slowly cooled to low temperatures had levels of respiration after warming and rehydrating similar to undried, unfrozen controls. Buds from undried twigs directly placed at -196°C and warmed gave little CO2 production.
624 PB 448 SHORT- AND LONG-VINE PUMPKINS INTERCROPPED WITH BEANS AND COWPEAS
Authors: Chesney P. , Wessel-Beaver L. , Elmstrom G. , Maynard D.
Published: February 2019

Rows of tropical pumpkins (Cucurbita moschata) are typically spaced 3-4 m apart Rows fill in 8 to 10 weeks after planting, potentially allowing a short-seasoned intercrop to be planted. A long-vine cultivar (PRB-150) and a short vine genotype (FL-I25×I21 - winter planting; FL-I25 - fall) were planted 0.9 m within rows by 1.8 between rows in Lajas and Isabela, PR in winter and fall of 1993. Either beans, cowpeas or no intercrop were planted on the same date as the pumpkin maincrop. Legume plots were harvested both green-shelled and dry. Pumpkin canopy cover, yield, fruit number and size were the same in intercropped and non-intercropped plots These same traits varied significantly in short vs. long vine plots (short vine plots were lower yielding with smaller fruits and less canopy cover). Plots planted with the short-vine maincrop generally produced greater legume yields. Harvest of dry beans or cowpeas was nearly impossible in long vine plots since the canopy covered the legume plants at that stage. Intercropped green-shelled bean yields averaged 800 kg/ha. Such a yield would add substantially to the income of the pumpkin maincrop.
628 PB 478 Trees, Crops and Soil Microbes Interact In Alley Cropping Systems
Authors: Seiter Stefan , William Ray
Published: February 2019

Red alder (Alnus rubra Bong) and black locust (Robina pseudoacacia L.) were intercropped in different planting patterns with sweet corn (Zea mays L.) in Corvallis, Oregon. In both years, sweet corn yield in alley cropping systems was significantly reduced when trees occupied more than 20 % of the total area. In the first year, higher yield were harvested in corn rows adjacent to the trees which compensated for reduced cropping area in the alley cropping systems. Low sweet corn yield coincided with high pruning biomass production. Red alder pruning biomass was small in the first year but equivalent to black locust in the following year. In the second year, soil microbial counts at planting time showed that bacterial and fungal activity in the tree rows was significantly higher compared to corn rows. At corn harvest, fungal activity was higher in tree rows and in corn rows adjacent to trees compared to corn rows more distant to the trees or corn rows in monocropping systems. It might be that higher sweet corn yield in rows next to the trees not only are the result of an increase in the amount of intercepted light but that below ground effects such as nitrogen mineralization from increased microbial activity or nitrogen transfer from the trees to the crop play an important role.
637 PB 363 XANTHOMONAS CAMPESTRIS PV. VESICATORIA INCREASES METHANOL AND ETHYLENE EVOLUTION FROM PEPPER LEAVES
Authors: Anderson Jeffrey A. , Maness Niels O. , Stall Robert E.
Published: February 2019

Bell pepper (Capsicum anuum L.) leaves inoculated with Race 1 of Xanthomonas campestris pv. vesicatoria (XCV) produced more ethylene and methanol than water-infiltrated controls in studies with leaves attached or detached during inoculation and dissipation of water-soaking. `Early Calwonder 20R'. a pepper genotype resistant to Race 1 of XCV, evolved more ethylene and methanol than `Early Calwonder 10R' (susceptible) following syringe inoculation of detached leaves with ≈ 7 × 107 cells/ml. A light intensity of ≈ 500 μmol· m-2·s-1 during dissipation of water-soaking of attached leaves triggered more ethylene and methanol than covering inoculated leaves with aluminum foil. Volatile hydrocarbon production from leaves infiltrated with distilled water was not significantly affected by light intensity during dissipation of water-soaking. The lipid peroxidation products, ethane and pentane, were not detected by headspace sampling following bacterial inoculation.
644 PB 404 SELECTION OF MICROORGANISMS FOR BIOLOGICAL CONTROL OF FUSARIUM SPP. IN ASPARAGUS
Authors: Elson Marshall K. , Kelly John F. , Nair Muraleedharan G.
Published: February 2019

Actinomycetes were isolated from asparagus field soil and bioassayed against Fusarium spp. in petri dishes. Extracts of the active organisms were bioassayed to determine if inhibition was caused by competition or antibiosis. The most active, antibiotic-producing organism was inoculated into test tubes with asparagus and Fusarium and evaluated for disease control. Asparagus seedlings were dipped in actinomycete suspension before planting in Fusarium-infested soil. These seedlings were evaluated for disease incidence after 8 weeks. Asparagus crowns could be dipped in actinomycete suspension before planting in the field.
RESISTANCE TO BOTRYTIS CINEREA IN PETUNIA
Authors: Krahl Kimberly H. , Randle William M.
Published: February 2019

Botrytis diseases are the most common and among the most destructive diseases affecting greenhouse-grown crops. Presently a combination of cultural control and fungicidal sprays are used to control the disease. Increasing energy and labor costs plus evidence of resistance of B. cinerea strains to commonly used fungicides has made the disease more difficult to control. A source of genetic resistance would provide an additional powerful and stable tool to control the incidence of Botrytis disease.

In this study screening techniques for Botrytis resistance in petunia were developed and 40 petunia genotypes were screened for resistance to B. cinerea. A wide range of variability for resistance to B. cinerea was discovered in petunia. Results indicate the presence of useful quantitative-type resistance to B. cinerea in petunia.
650 PB 022 DIFFERENT LETTUCE TYPES RESPOND SIMILARLY TO P FERTILIZATION
Authors: El-Hout N.M. , Sanchez C.A.
Published: February 2019

The production of lettuce (Lactuca sativa L.) types other than crisphead (i.e., leaf, boston, bibb, and romaine) has recently increased due to expanding consumer demand. Fertilizer P recommendations for these lettuce types are largely based on soil-test calibrations for the crisphead type only. However, biomass production and morphological traits of the different lettuce types vary. Four field experiments were conducted to compare the relative efficiencies of these lettuce types to P fertilization. All lettuce types showed large yield and quality responses to P. Because environmental conditions affected yield potential, P rates required for optimal yield varied by lettuce type within experiments. However, the P rates required for optimal yield were similar over all experiments. Furthermore, the relationship between relative yield and soil-test P across all seasons showed a similar soil-test P level was required for maximum yield of all lettuce types. The results of this study show that soil-test-based fertilizer recommendations for crisphead lettuce may be adequate for all lettuce types
655 PB 037 POTATO YlELD AND SOIL NlTRATE CONCENTRATIONS INFLUENCED BY NITROGEN APPLICATION AND ENVIRONMENTAL CONDITIONS
Authors: Sterrett S. B. , Midkiff D. V. , Savage C. P.
Published: February 2019

The influence of nitrogen source (commercial vs two slow-release sources), nitrogen rate at planting (56 vs 112 kg/ha) and nitrogen sidedress at early bloom (0, 56 lb N) on potato yield and soil nitrate concentrations was examined in a 3 year field study on a Bojac sandy loam soil. In each year significantly lower yields were recorded for one of the slow-release forms of N, but not the same source each year. Increased N applied at planting increased yield in 1992 and 1993, while sidedress N increased yield only in 1992. Soil nitrate concentrations in 1991 were substantially higher throughout the growing season than in 1992, particularly in the O-23 cm (surface) layer. Sidedressed nitrogen significantly increased soil nitrate concentration at 0-23, 23-46, and 46-99 cm depths, with the greatest increases recorded in 1991. The rain-fall during the growing season in 1991 was 23.5 cm, while in 1992 and 1993 rainfall was 38 and 31 cm, respectively. This study suggests that late N applications can contribute to nitrate movement through the soil profile without consistently improving tuber yield.
667 PB 113 IDENTIFICATION OF LINKED RAPD MARKERS TO IMPORTANT LOCI IN PEACH AND ALMOND
Authors: Warburton Marilyn L. , Bliss F. A.
Published: February 2019

Genetic linkage maps for many organisms are being produced using molecular markers. The utility of these maps depends on the ability to place genes of known, important effects on the map. It is often useful lo saturate the chromosome around these loci with many linked molecular markers. This study used Bulked Segregant Analysis and Random Amplified Polymorphic DNA to identify linked markers to loci in peach, Prunus persica L. Batch and almond Prunus dulcis Mill populations. Linkages to isozyme loci were first sought to test the suitability of this technique to long-lived perrenials. Several RAPD markers were found to be linked to three isozyme loci in a segregating F3 population from a peach × almond cross. PAPD markers have also been identified which are linked to the yellow-flesh locus of peach in a heterozygous peach population. Thus, this method has proven useful for identifying molecular marker linkages to important loci in peach and almond. These RAPDs may now be placed on a linkage map generated in our lab using a peach/almond hybrid population which will allow these loci to be studied and manipulated more easily in a breeding program.
675 PB 157 GENETIC RELATIONSHIPS OF JUGLANS REGIA L. CULTIVARS DETERMINED FROM RFLP ANALYSIS
Authors: Fjellstrom Robert G. , Parfitt Dan E. , McGranahan Gale H.
Published: February 2019

RFLP markers were used to study genetic diversity among California walnut (Juglans regia L.) cultivars and germplasm collected worldwide. 16 of 21 RFLP markers were polymorphic in the 48 walnut accessions tested. Seven RFLP markers permitted unique identification of all walnut cultivars. All genotypes were heterozygous at approximately 20% of the loci for both California and worldwide germplasm. California walnut germplasm contained 65% of the worldwide allelic diversity. Cluster analysis of genetic distance between accessions and principal component analysis of allelic genotypes showed two major groups of walnut domestication. California germplasm was associated with germplasm from France, Central Europe, and Iran, and had less genotypic similarity with germplasm from Nepal, China, Korea, and Japan.
685 PB 227 A SIMPLE COMPUTER PROGRAM FOR UPDATING WATER BUDGETS FOR IRRIGATED VEGETABLES
Authors: Simonne Eric H. , Kemble Joseph M. , Smittle Doyle A.
Published: February 2019

A TurboPascal computer program was developed to calculate daily water budgets and schedule irrigations. Daily water use (di) is calculated as pan evaporation (Ep) times a crop factor (CFi), where i is crop age. The water balance uses a dynamic rooting depth, the soil water holding capacity (SWC) and rainfall data (Ri). di is added to the cumulative water use (Di-1) and Ri is subtracted from Di. An irrigation in the amount of Di is recommended when Di approximates allowable water use. The program cart be adapted to most crop and soil types, and can be used for on-time irrigation scheduling or for simulating water application using past or projected weather data. This program should increase the acceptance of modem scheduling irrigation techniques by farmers and consultants. Additionally, this program may have application in an overall water management programs for farms, watersheds or other areas where water management is required.
689 PB 239 SOIL WATER POTENTIAL IRRIGATION CRITERIA FOR ONION PRODUCTION
Authors: Feibert Erik B. G. , Shock Clint C. , Saunders Monty
Published: February 2019

Onions were grown with different soil water potentials as irrigation criteria to determine the soil water potential at which optimum onion yield and quality occurs. Furrow irrigation treatments in 1992 and 1993 consisted of six soil water potential thresholds (-12.5 to -100 kPa). Soil water potential in the first foot of soil was measured by granular matrix sensors (Watermark Model 200SS, Irrometer Co., Riverside, CA) that had been previously calibrated to tensiometers on the same silt loam series. Both years, yield and market grade based on bulb size (more jumbo and colossal onions) increased with wetter treatments. In 1993, a relatively cool year, onion grade peaked at -37.5 kPa due to a significant increase in rot during storage following the wetter treatments. These results suggest the importance of using moisture criteria to schedule irrigations for onions.
692 PB 268 `HASS' AVOCADO RESPONSE TO DIFFERENTIAL IRRIGATION TREATMENTS
Authors: Stottlemyer D. E. , Arpaia M. L. , Meyer J. L. , Witney G. W. , Bender G. S.
Published: February 2019

The influence of three irrigation treatments on flowering, yield, tree growth, root distribution, and leaf analysis of mature `Hass' avocado (Persea americana Mill.) was investigated over a six year period (1987-1992). Three irrigation treatments; 60, 80, and 100% of evapotranspiration (ETc) were applied using low-volume spray emitters. The differential irrigation treatments were maintained year round. Irrigation treatments did not affect the timing or intensity of bloom. Yield data from years 2-6 show a significant irrigation effect on cumulative weight and total number of fruit per tree. Trees receiving 100% ETc had higher yield/tree. This increased yield was due both to increased fruit numbers and individual fruit weight per tree. Tree growth was also significantly impacted by the irrigation treatments. Trees receiving 100% ETc exhibited the greatest amount of vegetative growth over the study. Yield efficiency (Kg fruit/m3 canopy) was not influenced by irrigation treatment. Irrigation treatment did not significantly influence nutrient analysis taken in the fall of each year.
695 PB 277 INFLUENCE OF IRRIGATION FREQUENCY ON GROWTH OF BLACK MAPLE AND SUGAR MAPLE
Authors: Grave William R.
Published: February 2019

Differences in native habitat and leaf morphological traits have prompted speculation that black maple (Acer nigrum Michx.f.) is more drought resistant than sugar maple (A. saccharum Marsh.). In this study, growth of potted seedlings of the two species irrigated at 10-, 26-, or 42-day intervals was compared. For plants irrigated most frequently, dry mass, shoot: root ratio, stem length, and surface area of lamina were greater for sugar maple than black maple. The impact of drought was more pronounced in sugar maple than in black maple, causing reductions in stem length of ≈ 60% in sugar maple and ≈ 30% in black maple. Specific mass of lamina tended to be greater for black maple than sugar maple, particularly after drought, and it increased over time in both species. The slower growth, lower shoot: root ratio, and greater specific mass of lamina of black maple indicate. it is more drought resistant than sugar maple.
702 PB 318 SHELF-LIFE AND PHYSIOCHEMICAL PROPERTIES OF HIGHBUSH (VACCINIUM CORYMBOSLM) AND RABBITEY E-(V. ASHEI) BLUEBERRIES FOR FRESH MARKET
Authors: Marroquin E. , Silva J. L. , Garner J. O. , Magee J. B. , Braswell J. , Spiers J.
Published: February 2019

Three varieties of rabbit eye (Vaccinium ashei) blueberries (`Climax',, `Premier', and `Tifblue') were harvested in Mississippi and two varieties of highbush (v. corymbosum blueberries (`BlueCrop' and `Jersey') were harvested in Michigan. Each variety was harvested at three different locations as replications. The berries were rapidly cooled to 5°C after harvest, placed in 1-pint containers, and analyzed at 7-day intervals for 28 days with day 0 being 48 h after harvest.

Shear, compression and puncture forces were higher for rabbiteye spp. than for highbush spp. `Bluecrop' blueberries showed the lowest shear force whereas, Climax, had the most shear force. Puncture force (skin toughness) was lower for `Bluecrop' and `Jersey' and higher for, Climax, There was an increase in shear force by all varieties with storage time. `Premier, and `Climax' had lower soluble solids, but they increased with storage time. `Jersey' had the highest pH and `Tifblue' the lowest. Although all varieties lost moisture with time, `Bluecrop' always had higher moisture. Mold growth varied with time; however, `Bluecrop' had a higher percentage of moldy berries throughout refrigeration. The percent decay was higher for highbush blueberries after 16 d of refrigeration. Rabbiteye's toughness and firmness give them a longer refrigerated shelf-life over highbush blueberries.
722 PB 438 FRUIT QUALITY OF STRAWBERRY GUAVA
Authors: Mukai Hiroo , Takagi Toshihiko , Nakamura Yasuhiro , Suzuki Tetsuo
Published: February 2019

Fruit quality of strawberry guava, yellow strawberry guava (Psidium cattleianum Sabine) and red strawberry guava (Psidium cattleianum Sabine var. luidium) was investigated. Fruit weight of yellow strawberry guava ranged from 7.9 to 39.2 g, and that of red strawberry guava ranged from 3.6 to 15.9 g. Yellow strawberry guava was round, and red strawberry guava was ovoid, in fruit shape. strawberry guava fruit had many hard seeds. Yellow and red strawberry guava contained 16 to 137 and 5 to 33 seeds per fruit. Seed of red strawberry guava was bigger than that of yellow strawberry guava. Sucrose, glucose, and fructose were contained in strawberry guava fruit. Sucrose, glucose, and fructose contents of yellow strawberry guava fruit were 6.69%, 3.61%, and 6.27%, respectively. Those of red strawberry guava fruit were 9.52%, 2.09%, and 3.39%, respectively. Strawberry guava fruit contained about 1% of titratable acidity. Total ascorbic and dehydro-ascorbic acid contents of yellow strawberry guava fruit were 57.9 mg/100ml and 41.6 mg/100ml, respectively. Those of red strawberry guava were 81.4 mg/100ml and 74.4 mg/100ml, respectively. Fruit quality of strawberry guava was suitable to eat freshly.
724 PB 462 PHYSICOCHEMICAL PROPERTIES OF GUAVA PRODUCED IN GEORGIA
Authors: Yadava Umedi L.
Published: February 2019

Fully developed and ripe guava (Psidium guajava L.) fruits harvested during Sept-Dec 1993, from field-grown trees which were winter protected by 6-mil clear polyethylene, were examined for physical characteristics and nutrient contents. The purpose of this study was to establish optimum harvest time, fruit yield and physical characters, and nutritional fluctuations over a five week storage time. Fruits picked at turning stage, were observed for fresh weight, fruit girth (horizontal) and height (vertical), fruit volume, and fruit surface & flesh color evaluation (L* a* b* values by chromameter CR-200, Minolta Corp). Nutritional analysis (proximates, vitamins, and minerals) of fruits harvested on Oct 11, Oct 18, Oct 25, Nov 1, and Nov 8 and, refrigerated until analyzed, was performed at Food Science Department, University of Georgia. There were 342 fruits/tree with an average weight of 292 g, fruit girth 26.1” and height 7.5”. L* a* b* values for surface and flesh colors were. +65.61. -6.86, +39.37, and +55.86, +35.41, +19.48, respectively. Nutritional analyses indicated that the guava fruits were high in vitamin C (305 mg per 100 g fruit). K (201 mg), protein (1.4 g) and total dietary fiber (5.1 g) but low in fat (0.19 g per 100 g fruit) and Na (1.3 mg). The harvested fruit kept well for a five weeks period under refrigerated storage. Except for a modest loss of moisture, the storage period showed no significant effect on nutrient contents in the proximates, vitamins or mineral analyses indicating value of cool storage for guavas.
734 PB 026 EFFECT OF CO2 LEVEL ON COWPEA CANOPY PHOTOSYNTHESIS AND GROWTH
Authors: Ohler Tracy A. , Mitchell Cary A.
Published: February 2019

The vigorous growth habit and tolerances to heat, water, and acid stresses suggest cowpea as a candidate species for Controlled Ecological Life-Support Systems (CELSS). The low fat, high protein, moderate carbohydrate content of the edible leaves and seeds complement cereal grains in the vegetarian diets planned for CELSS. Cowpea canopy densities of 3.6, 7.2, 10.7, and 14.3 plants·m-2 were grown under CO2 levels of 400 or 1200 μl·l-1. Plants were grown in a deep-batch recirculating hydroponic system. pH was maintained at 5.5 by a pH controller with an in-line electrode. The nutrient solution was replaced as needed and sampled weekly for analysis by inductively coupled plasmaatomic emission spectrometry. Fluorescent lights provided 674±147 μmol·m-2s-1 PAR for an 8-hour photoperiod. Day/night temperature was maintained at 27/25°C. CO2 draw-down within the growth chamber was measured to calculate net photosynthesis. Power consumption was metered and canopy quantum efficiency was calculated. Crop yield rate (g·m-2·d-1). harvest index (% edible biomass), and yield efficiency (edible g·m-2·d-1·(nonedible g)-1) were determined to evaluate the productivity of cowpea for a CELSS. This study was supported by NASA Grant NAGW-2329.
738 Text ANATOMICAL DESCRIPTION OF THE FRUIT-RECEPTACLE DETACHMENT AREA IN CAYENNE PEPPER
Authors: Gersch Kay P. , Motsenbocker Carl E. , Lang Grezory A.
Published: February 2019

Two genotypes of cayenne pepper, Capsicum annuun, have been previously identified which differ significantly in ease of fruit detachment force. Both greenhouse- and field-grown plants of these genotypes, Cajun1-9027 and Cap-9004, were investigated for differences in cell type or organization where the fruit and receptacle join. Scanning electron microscopy revealed that mature fruit of genotype Cajun1-9027, which does not separate, exhibits a distinct region of sclerified cells that extend from the periphery of the fruit into the receptacle for at least 15 cell layers. In contrast, mature fruit of the more readily detachable genotype, Cap-9004, had fewer sclerified cells at the point of detachment. Neither genotype exhibits a well-defined abscission zone prior to, or at, maturity. Interpretation of histochemical staining of fruit-receptacle sections following ethylene treatment at different fruit developmental stages will be discussed.
741 PB 067 14CO2 MOVEMENT BETWEEN FLORICANES AND PRIMOCANES IN RED RASPBERRY DURING THE FRUITING CYCLE
Authors: Klauer Stenhen F. , Cameron J. Scott , Foote Paul W.
Published: February 2019

Results from previous cultural and physiological studies of red raspberry suggest that primocanes compete with floricanes for light, nutrients and/or photoassimilates. This study was undertaken to determine whether this competition might be reflected in the actual translocation of photoassimilates between the two types of canes. In 1993, pairs of greenhouse grown, potted red raspberry (Rubus idaeus L.) plants contaming one or two floricanes and numerous primocanes were labeled with 14CO2 on four dates corresponding with early anthesis, green fruit, red fruit and post fruit maturity stages of the growing season. For each experiment, either a floricane or a primocane was exposed to 92.5μCi 14CO2 within a sealed bag. After 24 hours, the bag was removed and the presence of label was monitored for up to 11 days. Activity was determined using liquid scintillation. At all developmental stages 14C moved from the labeled floricane to primocanes that were from 2.5 cm to 1.5 m tall and to the roots. Movement was quickest and relatively greatest at early anthesis, dccreascd during fruiting, and was still occuring at 2 months after fruit maturity. Small amounts of label were detected in roots of labeled primocanes at all stages, but trace amounts were present in fruit and other primocanes only at post fruit maturity.
743 PB 073 ANATOMICAL AND PHYSIOLOGICAL DIFFERENCES AMONG THREE SPECIES OF Fragaria
Authors: Kelley Bruce D. , Cameron J. Scott
Published: February 2019

Several anatomical and physiological parameters were measured in 32 genotypes of fragaia, including the cultivated strawberry (frapria × ananassa) and its progenitor speck F. chiloensis and F. virginiana Measurements were made using potted. runner-propagated, &month-old greenhouse-grown plants growing under long day (14/10) conditions.

Significant differences in CO2 assimilation rates (leaf area and dry weight bases). leaf chlorophyll content, leaf soluble protein content, and leaf anatomy were found between subspecies of F. virginana as well as among species. Recessed stomata and greater water use efficiency were observed in F. virginana ssp glauca as well as in F. chiloensis genotypes. In addition, it appears that leaf anatomy characteristics, as studied using light microscopy, may he useful in corroborating taxonomic decisions based upon gross morphology in Fragaria.
757 PB 155 LABORATORY RESPONSE TO DORMANCY-BREAKING TREATMENTS DIFFERS BY BUD AND CUTTING TYPE IN PEACH
Authors: Nir Gil , Lang Greg
Published: February 2019

Endodormant `Hawthorne' peach shoots were collected in early autumn and sectioned into long (30-40 cm), short terminal (10-15 cm), or short sub-terminal (IO-15 cm) cuttings. Dormancy-breaking treatments included application of hydrogen cyanamide H2C N2), thiourea (TU), sodium azide (NaN3) or gibberellic acid (GA3) solutions; atmospheric methyl jasmonate (MJ); hot water (50C for 1-2 h); or chilling (3.5C for 1-4 weeks). During forcing at 24C, & budbreak of all bud types on long cuttings was very low. On short cuttings, % apical budbreak was greater than % lateral vegetative budbreak, with almost no floral budbreak. Relative to H2CN2-induced lateral vegetative budbreak, budbreak induced by MJ, TIJ, GA,, and NaN3 was 17, 34, 50, and 92%, respectively. Relative apical budbreak was 0, 95, 53, and 63%, respectively. Addition of aminooxyacetic acid (AOA) to the beaker solution (in which cuttings were forced) induced apical, but not lateral, budbreak by itself; AOA synergistically improved H2CN2-induced budbreak by 23%. Latetal budbreak on short sub-terminal cuttings treated with hot water (1 h) was similar to that of H2CN2 treatment. Chilling increased apical budbreak to 100% as duration increased to 3 weeks, lateral vegetative budbreak only reached 43% after 4 weeks of treatment. The use of different bud and cutting types as model systems to study the differential regulation of dormancy by various treatments will be discussed.
769 PB 345 NUTRIENT PARTITIONING IN `NELLIE WHITE' EASTER LILIES GROWN UNDER TWO TEMPERATURE REGIMES
Authors: Whipker Brian E. , Kirk Terri , Hammer P. Allen , Miller William B.
Published: February 2019

`Nellie White' Easter lilies were grown under two day/night temperature regimes, a positive differential temperature (+DIF) of 15.5C night / 21C day temperature or a negative differential temperature (-DIF) of 19.4C night / 14.4C day temperature. At anthesis the plants were divided into 15 leaf-node segments, starting from the plant base (nodal position 0-15). The segments were further subdivided into leaf, stem and flower tissue parts, with fresh and dry weights being recorded, and tissue being analyzed for NH4-N, P, K, Ca, Mg, Na, Cu, B, Fe, Mn, and Zn.

Of the elements studied, only P content was statistically different at the DIF treatment × nodal position × tissue type interaction. Total 1eaf P per segment was higher in the -DIF plants, with the concentration increasing from 0.19 mg at nodal position O-15 up to the 1.34 mg at nodal position 46-60, compared to 0.16 and 0.76 mg, respectively, for the +DIF plants. There were also significant differences at the DIF treatment × tissue type, with -DIF leaf tissue having a higher total content of P, K, Mg, Ca, Na and B, while Cu was lower, than the +DIF leaf tissue. Results indicate that the distribution of nutrients in Easter lily plants are affected by growing temperature regimes.
781 PB 421 RAPID ANALYSIS OF CARBOHYDRATE CONCENTRATIONS IN MARIGOLD LEAF TISSUE USING NEAR INFRARED REFLECTANCE SPECTROPHOTOMETRY
Authors: Hou Guoqiang , Buxton Jack W. , Collins Michael
Published: February 2019

Studies were conducted to determine if near infrared reflectance spectrophotometry (NIR) could be used to rapidly determine nonstructural carbohydrate (TNC) concentrations in marigold tissue. Marigold seedlings were grown in natural light growth chambers. Light intensity and CO2 concentration were adjusted to establish leaf samples with a wide range of the carbohydrate concentration. NIR spectra were collected on dry, ground samples using a reflectance scanning monochromator. Conventional laboratory analysis values for the same samples were correlated with spectral data. Calibration statistics were as follows: TNC; standard error of calibration (SEC)= 1.73, R2= 0.95, standard error of prediction or perfomance (SEP) = 1.64, R2= 0.95; Starch, SEC = 1.35, R2= 0.96, SEP = 1.37, R2= 0.94; Soluble Sugars, SEC = 0.26, R2= 0.91, SEP = 0.29, R2= 0.84. These results show that the NIR method can be used to rapidly determine concentrations of nonstructural carbohydrates in marigold leaf tissue and suggest the possibility for routine assessment of carbohydrate status for optimum management of environmental factors.
786 PB 436 COMPARING ROSE RESPONSES TO VARIOUS ENVIRONMENTS USING THE ROSESIM COMPUTER GROWTH MODEL
Authors: Hopper Douglas A. , Meinke Troy T. , Store Virginia S.
Published: February 2019

The computer simulation model ROSESIM is based on `Royalty' rose (Rosa hybrida L.) growth response to 15 unique treatment combinations of photosynthetic photon flux (PPF), day temperature (DT), and night temperature (NT) under constant growth chamber conditions. Environmental factors are assumed constant over an entire day, but set points may vary over the duration of the crop. Anticipated values for factors may be read from an ASCII file, allowing a variety of strategies to be modeled and compared.

A Valentine's Day crop senario compared 2 management strategies for crop development time and flower quality: [1] constant 24/17.1 DT/NT for the entire crop, or [2] 15 days warm 30/20C DT/NT to promote bud break, 10 days 20/15C DT/NT to promote stem caliper and leaf size, 10 days 25/18C DT/NT to promote bud development, and remaining time to flower 20/15C DT/NT to enhance flower size and color. PPF was increased gradually over crop time as would occur naturally for Dec. to Feb. Strategy [2] had longer stems (63 vs. 50 cm), similar stem and leaf dry weights, but less flower bud dry weight (1.0 vs. 1.6 g), while flowering 2 days earlier (41 vs. 43 days after pinch). c:\pm4\ash94h.pm 4
787 PB 439 A MUTATION ALTERING AUXIN HOMEOSTASIS AND PLANT MORPHOLOGY IN ARABIDOPSIS THALIANA L. HEYNH
Authors: King Joseph J. , Stimart Dennis P.
Published: February 2019

In an attempt to analyze genetically the interaction of endogenous auxin concentration and adventitious root formation, an EMS mutagenized M2 population of Arabidopsis thaliana was screened for mutants with altered abilities to form adventitious roots. A selected recessive nuclear mutant, rooty (rty), is characterized by extreme proliferation of roots, inhibition of shoot development and other morphological alterations suggestive of auxin or ethylene effects. The rty phenotype occurs in wild type seedlings grown on auxin containing medium and relatively normal growth is stimulated in rty seedlings growing on cytokinin containing medium. Analysis by GC-MS found that endogenous IAA concentrations in rty are 2 to 17 times higher than in wild type depending on tissue type and IAA form. Dose response experiments with IAA and NAA indicated that rty does not express increased sensitivity to auxin. These data suggest that the rty phenotype is due to elevated endogenous auxin. A genetic map location for rty and possible roles for the wild type RTY gene product in regulating auxin concentration will be presented.