bluuebunny/crossref_metadata_2025 huggingface dataset:
Water Loss of Nerium oleander Planted in Two Soil types Under Two Irrigation Regimes
Authors: Lownds N.K. , Mackay W.A.
Published: January 2019

Water loss of Nerium oleander growing in two soil types was determined from mid-June through mid-October. Plants (1 year old, 3.8 liter) were obtained from a local nursery and transplanted in May into 18.9-liter Iysimeter pots containing either clay loam or bluepoint sand. Controls were lysimeter pots containing each soil type but without plants. Irrigation was applied at two rates, approximately field (pot) capacity and 50% of that amount. Irrigation frequency was determined by visual inspection of the plants and was held constant for both irrigation rates in a given soil type. Frequency ranged from 2 to 3 days for the sand and 2 to 5 days for the clay loam. Water loss was determined every 24 h. Plant water loss was higher at the higher irrigation rate. Decreasing irrigation rate by 50% resulted in a 20% to 40% reduction in plant water use in clay loam and a 15% to 30% reduction in sand without affecting plant quality. Plant water loss in the sandy soil was ≈50% greater than in clay loam 48 h after irrigation. Implications of these findings in developing an optimum irrigation model for landscape plants will be considered.
Effect of Some Chloride Salt Concentrations on Germination of Four Saudi Date Palm Cultivars
Authors: Shaheen Mohamed A.
Published: January 2019

Seeds of four Saudi date palm cultivars were germinated on a modified White's medium (liquid and solid) containing various concentrations of sodium, calcium, and magnesium chlorides. These salts were incorporated in the medium to simulate their concentrations in Saudi underground water commonly used for irrigation. Different germination responses were observed on the liquid and solid medium. Variations between the four test cultivars on the same medium also were noticed.
In Situ Prediction of Fresh and Dry Weight of Peach Fruit
Authors: Zegbe-D Jorge A.
Published: January 2019

To estimate the effect of treatments or cultural practices over fruit dimensions on peach, such as fresh and dry weight and equatorial and polar diameters (FW, DW, ED and PD, respectively), the use of destructive samples are frequent. These variables are generally not included, due to the time-consuming and research costs involved. With the purpose to determine in situ the FW and DW of fruit of seedling peach trees, two cubic regression models (CRM) were fitted with 1241 and 1119 field observations of FW, DW, and ED. To determine DW, fruits were cut off immediately and dried at 70C for 24-h. These measurements were taken during growing season of 1984 and 1985. At 2-week intervals, 12 samples were collected each year. Each sample consisted in harvesting randomly five fruits and around the middle part of trees. The CRM were fitted taking the mean of five fruits. FW and DW were used as dependent variables, while ED as independent variable. To validate both models, during the growing season of 1985, 11 samples (five fruits per sample) were taken again from other trees. The real and predicted values of FW and DW were analyzed by a linear regression model (IRM), to know the grade of adjustment between them. The CRM of both variables had significant fit (r2 = 0.975 and 0.941 for FW and DW, respectively). In contrast, the highest variation coefficient was observed in DW (29.14%), compared with FW (13.4%). In both cubic models, error mean square was the lowest compared to other models. The linear relation between real and predicted values ha values of r2 = 0.983 and 0.941 for FW and DW, respectively; while the variation coefficients were 9.59% (FW) and 17.32% (DW). The CRM's can be used in future seedling peach experimental works, to predict fruit weight after full bloom until harvest.
Soil Cation Balance Affects Tomato Fruit Color Disorders
Authors: Hartz T.K. , Giannini C. , Miyao E. , Valencia J. , Cahn M. , Mullen R. , Brittan K.
Published: January 2019

A survey of 140 processing tomato fields throughout central California was conducted in 1996–97 to determine whether soil factors affect the occurrence of the tomato (Lycopersicon esculentum Mill.) fruit color disorders “yellow eye” (a halo of yellow tissue around the stem scar) and white core (an abnormal amount of internal white tissue); these disorders render fruit unsuitable for use as peeled or diced product. All fields were planted in `Halley' or `Heinz 8892'. Soil samples (0–30 cm) were analyzed for pH, texture, TKN, bicarbonate extractable P, and ammonium acetate-extractable K, Ca, and Mg. Ripe fruit were rated for the incidence (%) of fruit affected by one or both of the disorders, blended color, and % soluble solids (SS). Soil K (in meq., expressed as a % of base exchange) was negatively correlated with the incidence of the disorders, while soil Mg was positively correlated. Fields with extractable K <2% of base exchange averaged 21% of fruits affected by one or both disorders, compared to only 4% of fruits affected in fields with K >2.5% of base exchange and a Mg/K ratio (meq. basis) <12. Percent SS was weakly correlated with extractable K, but blended color was unrelated to any soil factor. In 1997 field trials, both gypsum application (to displace soil Mg) and K fertilization significantly suppressed the color disorders but did not affect yield, blended color, or % SS.
Consumer Preferences in Mixed Prairie Wildflower Plantings
Authors: Davis G.L. , Schimelfenig J.
Published: January 2019

A goal of this study is to establish temporal evaluations of the problems homeowners may encounter when establishing mixed prairie wildflower plantings. These plantings are often attempted with the notion that the composition of the planting will remain static over time with little or no maintenance. Six combinations of wildflowers and prairie grasses were compared for consumer preference. A survey was conducted at the long-term forbs research plots during the Festival of Color, an open house event at the John Seaton Anderson Turfgrass and Ornamental Research Area, Univ. of Nebraska Agricultural Research Development Center near Mead, Neb. Of the 9000 participants in the festival, ≈850 visited the plots. Of those, nearly 300 completed the survey instrument. Results from the first year indicate that the majority of respondents were homeowners who do their own yard work. Most of them considered a low maintenance landscape to be an important way in which to conserve resources such as water and fertilizer and reduce pesticide use. Most had grown prairie wildflowers and considered them to be low maintenance. The study showed that, depending on the planting composition, it would require between 59 and 118 h of weeding to establish wildflowers in the majority of respondents' home landscapes, which were between 1717 m2 and 1525 m2. The majority (56%) of visitors preferred combinations that included annuals but excluded prairie grasses. The majority (66%) disliked the combinations of prairie grasses without the inclusion of wildflowers.
Effect of Four Training Systems on Growth and Productivity of `Cortland'/M.9 EMLA Apple Trees
Authors: Schupp J.R. , Koller S.I.
Published: January 2019

`Cortland'/M.9 EMLA trees were planted in 1991 at 1.8 ×4.2-m spacing. The trees were trained to one of four systems: 1) Vertical Axis; 2) Y trellis; 3) Solen; or 4) Palmette trellis. Tree survival was 86% for Palmette trees and approached 100% for the other three systems. Annual yield and cumulative yield per tree of Vertical Axis and Y trellis was twice that of Solen or Palmette. Tree vigor was sub-optimal relative to planting distance in this study. Trunk cross-sectional area of Vertical Axis trees was larger than that of trees trained to Solen or Palmette, while trees trained to Y trellis were intermediate in trunk growth. Canopy volumes of Vertical Axis and Y trellis trees were similar, and greater than that of Solen or Palmette trees. Fruit size on Solen and Palmette trees was larger than that of Y trellis trees in 1995 and 1996, while fruit size on Vertical Axis trees was intermediate. Cumulative yield per cubic meter of canopy volume was the same for all four systems, suggesting that differences in productivity among systems were attributable to the effects of tree training practices on tree size, not to differences among systems in precocity or efficiency. The low heading cut needed to establish the lowest tier of branches on the Palmette system reduced tree vigor and in some cases, resulted in mortality. The horizontal training of the primary branches of the Solen severely reduced tree vigor. In this study, where tree vigor was sub-optimal due to rootstock selection, the additional restrictions in tree growth resulting from restrictive training methods resulted in a significant loss in productivity.
Freezing Tolerance in Rhododendron and Its Association with Dehydrin Expression
Authors: Lim Chon C. , Krebs Stephen L. , Arora Rajeev
Published: January 2019

This study examines whether dehydrin expression in leaves is associated with varying levels of cold hardiness among evergreen rhododendrons. Initially, differences in leaf freezing tolerance (LFT) were determined within three groups of plants: 1) a cultivar group; `Chionoides' (CND), `Grumpy Yellow' (GY), and `Vulcan's Flame' (VF) 2) a segregating F2 population derived from a super coldhardy (R. catawbiense) × less-hardy (R. fortunei) cross, and 3) juvenile seedlings and mature plants of wild-collected R. maximum. LFTs in fully acclimated cultivars corresponded with their USDA hardiness zone ratings—CND (zone 4, –32 °C) GY (zone 7, –16 °C), and VF (zone 6, –19 °C). F2 segregation was characterized by a continuous, normal distribution of LFT values, with groups of progeny at the “tails” differing in their mean LFT by 20 °C. Juvenile seedlings of R. maximum exhibited LFTs that were 12 °C lower than LFTs from mature plants. Western blots of leaf proteins revealed a common 50-kDa dehydrin that accumulated during cold acclimation in all three cultivars and appeared to be quantitatively associated with LFTs. Isoelectric focusing of the 50-kDa Rhododendron dehydrin revealed two isoforms (pI 5.5 and 6.5). The more acidic isoform was detected only in the hardiest (CND) cultivar. Experiments are underway to examine qualitative and quantitative expression of dehydrins and its association with LFT in the segregating F2 population and in the group of R. maximum plants differing in physiological age.
Enhancement of Floral Initiation and Bud Development by Chilling of Root Cuttings in Primocane-fruiting Blackberries
Authors: Lopez-Medina Jose , Moore James N. , Kim Kyung-S.
Published: January 2019

In previous studies we found that primocane-fruiting blackberries (PFB) form flower buds soon after the plants start suckering from root cuttings collected in winter or early spring. Research was carried out to test if the same phenomenon holds true in summer-collected plant material. Root cuttings of A-1836, APF-13 and NC194 PFB were dug from the field on 31 July 1997 and stored in plastic bags at 2 °C for 32 days. On 1 Sept., freshly dug root cuttings along with the cold-treated ones were stuck in 3.8-L plastic pots, which were kept in a lath house for 4 weeks and then moved to a greenhouse under natural daylength. Significant differences occurred for plant emergence between chilled and non-chilled plants (16 days vs. 31 days, respectively). Transition from vegetative to floral phase was first observed in cold-treated A-1836 and APF-13 at five-node growth stage, with floral structures clearly evident in both selections at seven nodes of growth 45 days after planting. Chilled APF-13 and A-1836 started to bloom on 26 Nov. and 5 Dec., respectively. The first fruit of APF-13 were picked on 10 Jan. 1998. By this date, cold-treated NC194 and all non-cold-treated plants remained stunted with rosetted leaves, showing no signs of floral initiation. These findings present evidence that low-temperature exposure prior to shoot emergence greatly promotes flowering and fruiting in PFB. The results might have applicability in blackberry culture under greenhouse conditions.
Regional Differences in Plant Development, Water Relations, and Chloroplast DNA of Hard Maples
Authors: Hilaire Rolston St. , Graves William R.
Published: January 2019

Principal component analysis of foliar traits of hard maples (Acer saccharum Marsh. and Acer nigrum Michx. f.) near 43°N latitude clustered data into two populations composed of trees from different geographical regions. Seedlings from these two regions, and a third, geographically intermediate region, were grown in a greenhouse for 2 years with two irrigation frequencies to assess regional differences in plant development and water relations. Leaves from the most western region (west of 93°W longitude) had the highest specific mass (5.97 mg/cm2), trichome frequency (531/cm2), and stomate frequency (628/cm2). Across regions, plants irrigated frequently had more stomates (596/cm2) than plants irrigated sparsely (483/cm2). Traits similar across regions but higher with frequent irrigation included surface area and mass of lamina, shoot-to-root ratio, the ratio of lamina area to stem xylem diameter, and leaf water potential. Sparse irrigation caused a comparatively large decrease in stomatal conductance of plants from the most western region, and pressure-volume analysis showed no regional or irrigation effects on leaf osmotic potential at full turgor. Identical banding patterns resulted when Hinf I digested the PCR-amplified trnL-trnF intergenic spacer region of chloroplast DNA from each region; work with the rpL16 and ndhA introns is proceeding. Trichome frequency on abaxial leaf surfaces, which differs regionally both in nature and in controlled environments, is the most consistent character we have measured for discerning populations.
Genetic Modification of `Royal Gala' Apple by Agrobacterium-mediated Transformation and Colchicine-induced Mutation
Authors: Liu Qingzhong , Hammerschlag Freddi , Meng Rengong
Published: January 2019

As part of a program to develop transgenic Malus × domestica Borkh. cv. Royal Gala with improved disease resistance, transgenic diploid and tetraploid plants with cecropin MB39 gene were regenerated. Transgenic diploid plants were obtained from etiolated internodal explants by Agrobacterium tumefaciens-mediated transformation using the plasmid binary vector pGV containing a chimeric gene consisting of a secretory sequence from barley-amylase joined to a modified cecropin MB39 coding sequence and placed under control of wound-inducible osmotin promoter from tobacco. The integration of the cecropin gene into apple genome was confirmed by Southern blot analysis. The transformation efficiency was 1.5%. Both non- and transgenic tetraploid plants were produced by cocultivating leaf explants from wild type and transgenic diploid shoots with colchicine at 25 mg/L in apple regeneration medium containing 10 μM TDZ. Twenty-two tetraploid lines were obtained from 90 explants. Flow cytometry was used for ploidy determination. The tetraploid plants were distinguishable from the diploid on morphological as well as cytogenetic grounds. Both the transgenic diploid and tetraploid plants are now being evaluated for resistance to fireblight.
Spot Treatment of Granular Hexazinone in Wild Blueberries
Authors: Yarborough David E. , Hess Tim M.
Published: January 2019

Preemergence application rates of hexazinone have been reduced because of the concerns of it leaching into the groundwater. Spot treatments of a 10% granular fomulation of hexazinone, Pronone MG, would allow for selective post-emergence control of weeds not controlled by the reduced preemergence rate. For each weed species, St. Johnswort, bunchberry, bracken fern, dogbane, and witchgrass/fall panicum, 10, 1-m2 plots were established and treated with either 0, 1 or 2 hg/ha a.i. Pronone. Treatment dates were: 27 June 1996 for St. Johnswort, bunchberry, and bracken fern and 12 July 1996 for dogbane and witch grass/fall panicum. Cover was evaluated on 25 July and 17 Sept. 96. Weed and blueberry cover were assessed on 25 June 1997. Dogbane and bracken fern were initialy controlled the first year with the 2 kg/ha rate of Pronone being most effective. In the year after treatment, the dogbane at both rates and the bracken fern treated with the low rate recovered. St. Johnswort, witchgrass/fall panicum, and bunchberry was not significantly reduced by the postemergence treatment of Pronone. Heavy rainfall after treatment dates, including more than 3 inches of rainfall on 13 July 1996, may have influenced the hexazinone movement and reduced its effectiveness. The uncertainty of the timing and amount of precipitation make the success of this method doubtful.
Flavor Analysis of rin/+ and Other Tomato hybrids and Inbreds Using Sensory and Chemical Methods
Authors: Scott J.W. , Baldwin E.A.
Published: January 2019

Consumer dissatisfaction with commercial tomato (Lycopersicon esculentum Mill.) eating quality is well-known. An array of tomato cultivars were tested for overall flavor by experienced or trained taste panels over several seasons. Fruit were also analyzed for aromatic volatiles, soluble solids (SS), and titratable acidity (TA). `Solar Set' was the most consistent cultivar for overall flavor, always ranking in the most preferred statistical group. Cultivars that were bred for increased firmness, either by crossing firm lines (ultrafirms) or that were heterozygous for the ripening inhibitor (rin) gene, tended to rank low in overall flavor and sweetness. Comparisons made included ultrafirm lines, rin/+ hybrids with one to three backcrosses to the high-flavored parent of `Solar Set' (Fla. 7060), Fla. 7060, and `Solar Set' with two rin backcrosses. Experienced panel ratings were highest for Fla 7060 followed by the rin/+ hybrids (in descending order of backcrosses to Fla. 7060), followed by the ultrafirm lines. SS and TA were highest in one ultrafirm (SS = 9.1, TA = 0.68) and lowest in one of the rin/+ hybrids (SS = 6.3, TA = 0.37) while the rest of the samples showed intermediate values. Analysis of flavor volatiles showed Fla. 7060 to be generally higher in most volatiles compared to the ultrafims and two of the rin/+ hybrids. Significant differences were found for methanol, ethanol, 1-penten-3-one, hexanal, trans-2-hexanal, trans-2-heptenal, cis-3-hexenol, 2+3-methylbutanol, 6-methyl-5-hepten-2-one, 2-isobutylthiazole, and geranylacetone.
Evaluation of Herbicides for Control of Annual Weeds in Asparagus (Asparagus officinalis)
Authors: Diaz Gerardo Martinez , Carvajal Arturo Lopez , Leonel Grijalva Contreras R.
Published: January 2019

This research was conducted under field conditions in 1993 with a cooperative farmer with the aim of evaluating the effects of herbicides for the control of annual weeds (pre-emergence). The herbicides and rates (a.i./ha) applied were: Diuron 2.4 and 1.2 L, Linuron 1.5 and 0.7 L, Metribuzin 1.4 and 0.7 L, Simazina 1.5 L, Trifluralin 1 L and Naptalam+ Bensulide 4+3 L and 2+2 L. Two check plots were also included, one free of weeds and the other with weeds. A randomized block design was used with four replicates. The experimental units were 4.5 × 10-m plots. Trifluralin showed 56% of control and Naptalam+ Bensulide exhibited 24% at both rates, while Diuron (97% to 100%), Linuron (87% to 96%), Metribuzin (96% to 100%), and Simazina (96%) showed the best controls with either doses; of these, Linuron at 0.7 L/ha registered the lowest control (87%). None of the herbicides evaluated showed any plant toxicity.
Establishment of Prairie Forbs and Grasses after Production in Compacted Media
Authors: Cavender Nicole , Thomas Laura , Knee Michael
Published: January 2019

Native prairie plants are believed to grow better in compacted soils than traditional bedding plants. We used 10 species of forbs and grasses to test the hypothesis that establishment in the field would be improved by greenhouse production of seedlings in compacted media and in topsoil as opposed to a peat-based medium. Media were compacted by applying 50 g·cm–2 while filling cells in a tray. Uncompacted controls were simply loose-filled. The seedlings were transplanted into plots that were untilled or tilled. Plants were photographed with a digital camera at different stages and the images were analyzed by computer to estimate growth non-destructively. At the time of transplanting estimated area per seedling was 15 to 140% higher for plants grown in compacted media than in uncompacted for 10 out of 13 species. Preliminary observations indicated that differences between plants from compacted and uncompacted media persisted in the field and that plants grew better in the tilled plots than in untilled. Seedling area was similar after production in topsoil or peat medium and there was no overall difference in the field. Plants from seedlings produced in topsoil were larger than those from peat-based medium in untilled plots but the converse was true for plants in tilled plots.
Re-evaluation of a Desiccating Surfactant for Thinning Peach Blossoms
Authors: Ebel R.C. , Himelrick D.G. , Caylor A. , Pitts J.
Published: January 2019

The surfactant “Surfactant WK” (dodecyl ether of polyethylene glycol) was applied to peach trees [Prunus persica (L.) Batsch] at full bloom over 3 years. Blossoms died rapidly, so that within 2 days dead blossoms could be distinguished easily from live blossoms or set fruit. There were strong (R2 > 0.87), linear correlations between concentration of “Surfactant WK” applied and percent blossoms removed and fruit set, which were similar over the 3 years. Trees were hand-thinned according to commercial practices after treatment. There was similar cropload, fruit weight and yield across treatments at harvest indicating no negative effects by the chemical on productivity. There was only slight limb damage at the highest concentrations of “Surfactant WK”, which over thinned blossoms. We recommend that based on the effectiveness, consistency, and lack of significant phytotoxicity, “Surfactant WK” be re-evaluated as a thinning chemical for peach trees.
An Annotated Pest Management Database with Field Decision-making Guides for the Mid-Atlantic Region
Authors: Kline W.L. , Kline S.T. , Rabin J. , Whalen J.M. , Spellman M.P. , Holmstrom K.E.
Published: January 2019

Integrated Pest Management (IPM) information is available in various forms to help cooperative extension agents and private consultants. Scouting forms, manuals, fact sheets, bulletins, and books have been written over the past few years to cover all aspects of IPM. Some of this information has not been published or is no longer available and can only be obtained from the authors. This makes it difficult to obtain historical or even new information. A Northeast Region Sustainable Agriculture Research Education (SARE) grant was received to evaluate and improve delivery systems for integrated crop and pest management. As part of the grant, a searchable database was created in FileMaker Pro™ so individuals can search for information on a specific crop or pest. There are 1580 entries covering 49 vegetables, 12 field crops, and three small fruits. Each entry has a summary and key words; where and how to obtain the document; crops and pests included; the audience for the publication, e.g. extension agent, researcher, agribusiness, gardener, etc.; and the type of publication, e.g. fact sheet, website, scouting form, etc. All categories within the database are searchable with pull down screens where appropriate. The database is integrated with a series of laminated field decisionmaking guides. These 2-page guides contain information on the damaging stage of the pest, monitoring stage, sampling methods, sampling frequency and thresholds. Information included in the field guides comes mainly from research in the mid-Atlantic region. Additional information related to the crop or pest can be obtained by searching the database by the use of key numbers listed in the guide. Each database entry has a key number for identification. The field guides are being validated in 1998 and both will be available in late 1998.
AFLP-derived, Codominant Markers for Locus-specific Applications
Authors: Bradeen James M. , Simon Philipp W.
Published: January 2019

The amplified fragment length polymorphism (AFLP) is a powerful marker, allowing rapid and simultaneous evaluation of multiple potentially polymorphic sites. Although well-adapted to linkage mapping and diversity assessment, AFLPs are primarily dominant in nature. Dominance, relatively high cost, and technological difficulty limit use of AFLPs for marker-aided selection and other locus-specific applications. In carrot the Y2 locus conditions carotene accumulation in the root xylem. We identified AFLP fragments linked to the dominant Y2 allele and pursued conversion of those fragments to codominant, PCR-based forms useful for locus-specific applications. The short length of AFLPs (≈60 to 500 bp) precludes development of longer, more specific primers as in SCAR development. Instead, using sequence information from cloned AFLP fragments for primer design, regions outside of the original fragment were amplified by inverse PCR or ligation-mediated PCR, cloned, and sequenced. Differences in sequences associated with Y2 vs. y2 allowed development of simple PCR assays differentiating those alleles. PCR primers flanking an insertion associated with the recessive allele amplified differently sized products for the two Y2 alleles in one assay. This assay is rapid, technologically simple (requiring no radioactivity and little advanced training or equipment), reliable, inexpensive, and codominant. Our PCR assay has a variety of large scale, locus-specific applications including genotyping diverse carrot cultivars and wild and feral populations. Efforts are underway to improve upon conversion technology and to more extensively test the techniques we have developed.
Physiological Evaluation and Field Assessment of Floricane Productivity of Cold-damaged Red Raspberry in a “Recovery” Year
Authors: Chen Chuhe , Cameron J. Scott , Klauer Stephen F.
Published: January 2019

The two test sites paired perennially cold-damaged portions of field vs. controls were monitored and assessed the same as last season. The winter of 1996–97 did not produce the same level of winter injury as the previous winter, thus this season was an opportunity to evaluate the effects of a “recovery” year. The overall cane lengths and bud number per cane were higher in the previously winter injured plots of both fields compared to the control. It showed the previous injured plants with a reduced crop load in 1996 were able to devote more energy into developing the 1997 crop. However, damaged plots still had higher cane dieback, percentage of cane dieback, number of dead or dormant buds per cane, and percentage of dead or dormant buds in both sites, especially at site 2, even in a mild 1996–97 winter. The control plots had greater average lateral length, total lateral length, and higher berry numbers per lateral, especially in laterals from primary buds at both sites. Thus, a mild winter reduced productivity of the floricanes and its laterals in the cold damaged plots. The differences in fruit yield and its components between the check and the cold-damaged ones were not significant this season. Leaves on the cold damaged floricanes had greater photosynthetic activity after harvesting than the control. The winter-injured plants with a reduced leaf area may show higher demand for photosynthate.
Components of Apple Fruit Epicuticular Wax and Growth of Sooty Blotch Disease
Authors: Belding Robert D. , Sutton Turner B. , Blankenship Sylvia M. , Young Eric
Published: January 2019

Sooty blotch severity varied among: `Smoothie Golden Delicious', `Coop-17', `Liberty', `NY65707-19', and `NY61356-22', apple cultivars surveyed In this study, Peltaster fructicola Johnson, Sutton et Hodges, and Leptodontidium elatius (F. Mangenot) Hoog were grown on compounds that make up the epicuticular wax of the fruit in order to determine if one or more wax compound acted as a substrate for growth, or if a growth modifier could be identified. There were no relationships between the major epicuticular wax components of each cultivar and the severity of the disease. P. fructicola and L. elatius, two of the most important sooty blotch fungi, did not grow on any of the five major components of the epicuticular wax. SEM studies showed that mycelia of P. fructicola grew on the surface of the wax and did not appear to degrade it. In view of the fact that conidia germination requires pre-treatment with dilute apple juice and the fact that SB does not grow on fruit cuticles where russet creates an impermeable layer. We conclude that the SB fungi are epiphytic and obtain their nutrients primarily from fruit leachates and not from components of the cuticle.
Commodity Heating Medium and Mexican Fruit Fly Mortality
Authors: Shellie Krista C.
Published: January 2019

The objective of this research was to investigate whether the medium used to transfer heat to a commodity influenced the mortality of Mexican fruit fly larvae. A similar 2-h heat dose was delivered to grapefruit via immersion in a variable temperature water bath or via exposure to a rapidly circulating gas. The concentration of oxygen and carbon dioxide inside the grapefruit was analyzed at 30-min intervals and grapefruit center temperatures recorded every 60 s during heating. The mortality of larvae located inside grapefruit during heating in a controlled atmosphere or in hot water was significantly higher than that of larvae located inside grapefruit heated in air. The internal atmosphere of grapefruit heated in a controlled atmosphere or in hot water contained significantly higher levels of carbon dioxide and lower levels of oxygen than grapefruit heated in air. Larval mortality was compared after larvae were heated in media by rapidly circulating air or by an atmosphere containing 4 kPa of oxygen and 18 kPa of carbon dioxide to evaluate whether the altered atmosphere or a heat-induced fruit metabolite was responsible for enhanced mortality. The significantly higher mortality of larvae heated in media in the presence of an altered atmosphere suggested that the altered atmosphere enhanced larval mortality. Results from this research suggest that reducing oxygen and or increasing the level of carbon dioxide during heating can enhance mortality of the Mexican fruit fly and potentially reduce the heat dose required for quarantine security.
Whole Plant Measurement of Photosynthesis and Development of Apple Trees in Relation to Pest Damage
Authors: Breitkreutz Sarah , Flore James
Published: January 2019

The objectives of this study were to determine the relationship of whole-plant photosynthesis (WPP) and overall growth of apple trees to the damage caused by insects and disease. This project was part of a larger experiment involving a pest control system consisting of different control strategies, with integrated pest management being one. WPP was measured seven times during the 1997 growing season on 16 single-tree replicates of apple trees from two varieties, `Empire' and `Liberty', on M-9 rootstocks at the Clarksville Horticulture Experiment Station. WPP was measured on trees subjected to six pesticide and fungicide treatments that were part of the established study. In addition to these measurements, the leaf number and area were determined at the time of the measurement. At three times during the growing season, an estimation of insect damage to the fruit and foliage were determined. At harvest, the total number, size distribution, and weight of the apples from each tree was measured. In addition, an estimation of pest and disease damage to the fruit was conducted. Results showed a decrease in the rate of WPP as the season progressed. All of the treatments had higher rates of photosynthesis than the control trees. In addition, the soft chemical treatments had higher rates of photosynthesis than the conventional IPM treatments, 1.8 and 1.5 mmol CO2/cm2 trunk cross sectional area per s, respectively. Further details of these results and the relationships between foliage damage, photosynthesis and tree yield will be presented.
Nondestructive Quality Evaluation of Tomatoes
Authors: Hakim A. , Purvis A. , Pehu E. , Voipio I. , Kaukovirta E.
Published: January 2019

Both external and internal quality of fruits such as tomatoes can be evaluated by different methods, but all most all of the methods are destructive. For this reason, there is a need to reassess some of the alternative techniques. Nondestructive quality evaluation is an attractive alternative. The principles of different nondestructive quality evaluation techniques such as optical, physical, and fluorescence techniques applied to tomato fruit is explained. Successful application of these techniques that could be used for evaluation of different quality attributes are illustrated. The advantages of nondestructive quality evaluation techniques are that they are very fast, easy, labor- and time-intensive, and inexpensive. These techniques could also be useful to evaluate the quality of other vegetables.
The Use and Adaptation of Existing Measurement Tools in People-Plant Research.
Authors: Dawson Carol S. , Zajicek J.M.
Published: January 2019

Measurement of variables in physical science research is usually accomplished through the use of mechanical instruments, e.g., rulers, thermometers. The study of the effects of various horticultural activities on people often requires the measurement of mental constructs such as attitudes, opinions, and psychological characteristics. However, the measurement of these variables is not straight-forward. Fortunately, many measurement instruments have already been developed and tested by psychologists and educators which measure variables of interest to researchers studying human issues in horticulture. This workshop will review the types of instruments available and will focus on measures of environmental attitude, and psychological profiles. Criteria for selecting instruments appropriate to specific populations will be discussed. Finally, suggestions for integrating the results of these measures into a human issues in horticulture study will be given.
Laboratory Exercise on the Segregation of Flower Color and Related Genes Using Salpiglossis sinuata
Authors: Lee Chiwon W.
Published: January 2019

Velvet flower (Salpiglossis sinuata, Solanaceae) can be used as an excellent demonstration plant for horticultural crop breeding classes. Salpiglossis produces large trumpet-like flowers exhibiting an assortment of corolla color and pigmentation pattern. The pistil is large (3 to 4 cm long) with a sticky stigmatal tip and anthers can be easily emasculated prior to anthesis. The large pollen grains are shed in tetrads, which can be separated and individually placed on the stigma. It takes 8 to 9 weeks from seeding to blooming, with a prolific flowering cycle repeated in flushes. Numerous seeds (about 750/capsule) are obtained in 3 weeks after self- or cross-pollination. The influences of three genes that control flower color and pigmentation pattern can be conveniently demonstrated with their dominant and recessive alleles. The R gene controls flower color with red (RR or Rr) being dominant over yellow (rr) flower color. The D gene controls the density of pigmentation with solid (DD or Dd) color being dominant over dilute (dd) color. Corolla color striping is controlled by the St gene with striped (stst) being recessive to non-striped (StSt or Stst) pattern. For example, by using diploid lines of genotypes RRDD (red, solid), RRdd (red, dilute), or rrdd (yellow, dilute) and their crosses, students can easily learn a dominant phenotypic expression in the F1 hybrid and the digenic 9:3:3:1 segregation ratio in the F2 progeny. Another gene (C) that controls flower opening can also be used to show its influence on cleistogamous (closed, self-pollinated, CC or Cc) versus normal chasmogamous (open-pollinated, cc) corolla development. In addition, the induction and use of polyploid (4X, 3X) plants in plant breeding can be effectively demonstrated using this species.
Root Initiation in Debladed Petioles from Juvenile and Mature English Ivy in Response to Inhibitors of Ethylene Biosynthesis and Action
Authors: Geneve Robert L. , Hackett Wesley P. , Swanson Bert T.
Published: January 2019

Several inhibitors of ethylene biosynthesis and action, as well as an atmospheric ethylene scrubber, were used to investigate the role of ethylene in adventitious root initiation in de-bladed petioles from the juvenile and mature phase of English ivy (Hedera helix L.). Induction of root primordia required NAA regardless of the inhibitor treatment. Difficult-to-root mature petioles have been shown to produce higher amounts of ethylene than easy-to-root juvenile petioles. However, mature petioles failed to root under any combination of NAA and inhibitor treatment, indicating that the continued evolution of ethylene in NAA-treated mature petioles was not responsible for the absence of a rooting response. Root initiation in juvenile petioles was not affected by treatment with the ethylene action inhibitors STS and NDE, nor by removal of atmospheric ethylene with KMnO. Inhibition of ethylene biosynthesis using AVG or AOA reduced root initiation in juvenile petioles, but this response was not well-correlated to the observed reduction in ethylene evolution. The inhibitory action of AVG could not be reversed by the addition of ethylene gas or ACC, which indicated that AVG could be acting through a mechanism other than the inhibition of ethylene biosynthesis. Chemical names used: 1-naphthalene acetic acid (NAA); l-aminocyclopropane-l-carboxylic acid (ACC); silver thiosulfate (STS); 2,5-norbornadiene (NDE); aminoethyoxyvinyl-glycine (AVG); aminooxyacetic acid (AOA).
Characterization of sugary-1 (su-1) sugary enhancer (se) Kernels in Segregating Sweet Corn Populations
Authors: La Bonte Don R. , Juvik John A.
Published: January 2019

A single-kernel, sugar analysis technique was used to study the genetic relationship between morphological and metabolic traits previously associated with expression of the sugary enhancer (se) endosperm mutation in a su-1 sweet corn (Zea mays L.) background. Analysis of sucrose and total carotene content in su-1 kernel populations segregating for se showed that light-yellow kernel color was a reliable phenotypic indicator for kernels homozygous for the se gene. High levels of kernel maltose was not always indicative of su-1 se kernels in mature (55 days after pollination) kernel populations. Characteristic high levels of percent moisture in su-1 se kernels at 28 and 35 days post-pollination were identified as an expression of high sugar content. Kernels homozygous for su-1 se were also found to weigh less at maturity than su-1 Se kernels, and se was found to be partially expressed in a heterozygous condition.
Inheritance of Purple Spathe in Anthurium
Authors: Wannakrairoj Surawit , Kamemoto Haruyuki
Published: January 2019

A scheme for the genetic control of purple spathes in Anthurium is proposed. The recessive allele p modifies the color of anthocyanins controlled by the M and O loci. A spathe is purple when the genotype is M-O-pp. If the P locus is dominant, M-O- is red, while mmO - is orange. The p allele has no effect on the -00 (white) genotype.
Inheritance of Cracking and Scarring in Pepper Fruit
Authors: Johnson Deborah , Knavel Dean E.
Published: January 2019

Cracking and scarring of pepper (Capsicum annuum L.) fruit are under genetic control in families having the cultivar Serrano Chili as the P1 parent. Fruit of `Serrano Chili' exhibited slight cuticle cracking or scarring, with no wall cracking, for an average rating of 2.2. Fruit cracking ratings of the P2 parents (`Anaheim Chili', `Red Cherry Small', and `Keystone Resistant Giant') were 1.0, 1.0, and 1.8, respectively, whereas ratings for F, (`Serrano Chili' × `Anaheim Chili'), F1(`Serrano Chili' × `Red Cherry Small'), and F, (`Serrano Chili' × `Keystone Resistant Giant') were 3.5, 2.8, and 3.5, respectively—an indication of overdominance. Cracking ratings in F2 and BCP2 populations were very similar and shifted toward the mean of the P2 parent within each family, while ratings in the BCP1 populations were similar to the F1 mean. Estimates of gene effects for cracking were mostly dominant, with some additive effects in `Serrano Chili' × `Anaheim Chili' and `Serrano Chili' × `Keystone Resistant Giant' families, and additive × additive epistasis in `Serrano Chili' `Keystone Resistant Giant'. Plants selected from segregating generations for either high and low scarring or high and low cracking produced progeny the following year with lower ratings than their respective mother's rating the previous year. Since cracking and scarring were significantly correlated with length, diameter, and length: diameter ratio of fruit in only a few generations and in segregating progeny of selected plants, fruit shape has minimal relationship to cracking and scarring.
Productivity Under Shade in Hawaii of Five Crops Grown as Vegetables in the Tropics
Authors: Wolff Xenia Y. , Coltman Robert R.
Published: January 2019

`Waimanalo Long' eggplant (Solanum melongena L.), `Kahala' soybean [Glycine max (L.) Merrill], `Jumbo Virginia' peanut (Arachis hypogea L.), `Waimanalo Red' sweet potato [Ipomea batatas (L.) Lam.], and `Green Mignonette' semihead lettuce (Lactuca sativa L.) were field-grown in two seasons at Waimanalo, Oahu, Hawaii, in the open sun and with four artificially produced levels of shade (30%, 47%, 63%, and 73%). Yields and vegetative growth of eggplant, soybean, peanut, and sweet potato decreased linearly with increasing shade levels. Compared to unshaded controls, yields of semihead lettuce increased significantly under 30% shade in Fall 1986. During Spring 1987, lettuce yields were reduced only slightly from unshaded levels by increasing shade up to 47%. Leaf areas of index leaves of eggplant, soybean, and lettuce were similar to unshaded controls as shade intensity increased, while leaf dry weight decreased under shade. By comparison, both leaf area and leaf dry weight of peanut index leaves decreased as shade increased. Leaf area and leaf dry weight of sweet potato did not respond to shading. The results indicate that, of the five crops studied, only lettuce can be grown successfully under lightly shaded conditions and still receive enough radiant energy for maximum photosynthesis and yields.
Productivity of Eight Leafy Vegetable Crops Grown Under Shade in Hawaii
Authors: Wolff Xenia Y. , Coltman Robert R.
Published: January 2019

`Green Mignonette', `Salinas', `Parris Island Cos', and `Amaral 400' lettuce (Lactuca sativa L.); `WR-55 Days' Chinese cabbage (Brassica rapa L. Pekinensis Group); Waianae Strain' green mustard cabbage [Brassica juncea (L.) Czerniak]; `Tastie Hybrid' head cabbage (Brassica oleracea L. Capitata Group); and an unnamed local selection of green bunching onions (Allium fistulosum L.) were field-grown during Fall 1987 and Spring 1988 at Waimanalo, Oahu, Hawaii, in full-sun and with four artificially produced levels of shade (30%, 47%, 63%, and 73%). Yields of cos lettuce, green mustard cabbage, and green bunching onions were irresponsive to shade or negatively affected by shade in both seasons. Yield responses of the other crops to shade varied seasonally. Optimum shading of 30% to 47% increased `Green Mignonette', `Salinas', and `Amaral 400' lettuce yields by 36% and head cabbage and Chinese cabbage yields by 23% and 21%, respectively, compared to full-sun plots in one or both seasons. Leaf areas similar to unshaded controls were maintained as shade intensity increased, while leaf dry weight decreased in all crops except `Salinas' and `Parris Island Cos' lettuce. Maximum rates of net photosynthesis (Pn) were attained at 1500 umol·s-1·m-2, which was about two-thirds of full sunlight.
Duration of CO2 Enrichment Influences Growth, Yield, and Gas Exchange of Two Tomato Species
Authors: Yelle Serge , Beeson Richard C. , Trudel Marc J. , Gosselin André
Published: January 2019

Lycopersicon esculentum Mill. cv. Vedettos and Lycopersicon chmielewskii Rick, LA 1028, were exposed to two CO2 concentrations (330 or 900 μmol·m-3) for 10 weeks. The elevated CO2 concentration increased the relative growth rate (RGR) of L. esculentum and L. chmielewskii by 18% and 30%, respectively, after 2 weeks of treatment. This increase was not maintained as the plant matured. Net assimilation rate (NAR) and specific leaf weight (SLW) were always higher in C02-enriched plants, suggesting that assimilates were preferentially accumulated in the leaves as reserves rather than contributing to leaf expansion. Carbon dioxide enrichment increased early and total yields of L. esculentum by 80% and 22%, respectively. Carbon exchange rates (CER) increased during the first few weeks, but thereafter decreased as tomato plants acclimated to high atmospheric CO2. The relatively constant concentration of internal C0 with time suggests that reduced stomatal conductance under high CO2 does not explain lower photosynthetic rates of tomato plants grown under high atmospheric CO2 concentrations. Leaves 5 and 9 responded equally to high CO2 enrichment throughout plant growth. Consequently, acclimation of CO2-enriched plants was not entirely due to the age of the tissue. After 10 weeks of treatment, leaf 5, which had been exposed to high CO2 for only 10 days, showed the greatest acclimation of the experiment. We conclude that the duration of exposure of the whole plant to elevated CO2 concentration, rather than the age of the tissue, governs the acclimation to high CO2 concentrations.
Physiological Response to Chilling Temperatures of Intermittently Warmed Cucumber Fruit
Authors: Cabrera Roberto M. , Saltveit Mikal E.
Published: January 2019

Symptoms of chilling injury were reduced by intermittently warming cucumber fruit (Cucumis sativus L. cv. Poinsett 76) from 2.5 to 12.5C for 18 hr every 3 days. Fruit continuously held at 2.5C for 13 days developed severe pitting and decay after 6 days at 20C, while fruit continuously held at 12.5C or intermittently warmed showed no pitting or decay during subsequent holding at 20C. The increased rate of C2H4 production during the first warming period, from 12 nl·(kg·hr)-1 at 2.5C to 201 nl·(kg·hr)-1 at 12.5C, was significantly greater than that during the second or third warming periods, i.e., 53 to 98 and 53 to 55 nl C2H4/(kg·hr), respectively. Respiration increased 3-fold during the initial warming period, but only 2-fold during subsequent warming periods. Leakage of cellular ions from excised disks of mesocarp tissue was around 6% and 10% of the total ion content of the tissue for control and intermittently warmed fruit, respectively, but increased to 17% for fruit that were continuously held at 2.5C for 10 days. After 320 hr (three cycles) of chilling and warming, chilled fruit showed significantIy lower ethylene-forming enzyme activity than the control or intermittently warmed fruit. Fruit held at 12.5C contained 0.09 to 0.34 nmol·g-1 of ACC. ACC levels were 6.23 nmol·g-1 in fruit exposed to 2.5C for 320 hr. In contrast, intermittently warmed fruit only showed 30% and 27% increases in ACC content during the first and second warming periods, respectively. Periodic warming appears to allow chilled fruit to acclimate to subsequent periods of chilling. Chemical names used: 1-aminocyclopropane-1-carboxylic acid (ACC).
Prestorage Heat Treatment as a Means of Improving Poststorage Quality of Apples
Authors: Klein Joshua D. , Lurie Susan
Published: January 2019

The benefits conferred by a prestorage heat treatment on poststorage quality of apples (Malus domestics Borkh.) were measured on `Anna', a non-storing early cultivar, and `Granny Smith', a long-storing late cultivar. The major benefit was a decrease in rate of apple softening, both during OC storage and during simulated shelf life at 20C. Soluble solids concentration was not affected by heat treatment, but titratable acidity was reduced. Ethylene production after heat treatment and storage was similar to or higher than that of control apples, but respiration was lower. The optimum temperature and time combination for prestorage treatment of both cultivars was 4 days at 38C.