bluuebunny/crossref_metadata_2025 huggingface dataset:
(53) Do Pawpaw Varieties Behave Differently during Ripening and Cold Storage?
Authors: Galli Federica , Archbold Douglas D. , Pomper Kirk W.
Published: February 2019

Pawpaw[Asiminatriloba (L.) Dunal] is a highly perishable climacteric fruit. Generally, fruit may be stored at 4 °C for 4 weeks with minimal loss in quality or subsequent ripening capacity. However, comparisons among cultivars and advanced selections for ripening behavior and postharvest storage life have not been reported. Ideally, cultivars with superior ripening traits (higher firmness, or a slower rate of firmness loss) and longer storage life may be identified for the commercial market. To determine if differences among genotypes may exist, respiration, C2H4 production, and fruit firmness of six varieties, 8-20, 9-58, `Middletown', `PA Golden', `Taytwo', and `Taylor', were measured during ripening after harvest and after 1, 2, 3, 4, 5, and 6 weeks of 4 °C storage. No differences were observed among the cultivars regarding respiration and C2H4 production. Respiratory and ethylene peaks were detected within 48 hours after harvest or removal from cold storage. Rapid loss of firmness was measured during ripening at ambient temperature after harvest and after removal from cold storage (days 0–3), with some loss during cold storage itself (weeks 1–6). As expected, firmer fruits at harvest had a lower respiration rate. However, no obvious differences in ripening behavior or cold storage response were observed among the six genotypes. As a general guideline, only firmer fruits should be cold stored, since fruit softening did not stop at 4 °C. A broader analysis of all of the named cultivars and advanced selections of pawpaw will be needed to determine if the present results are generally representative of pawpaw.
(261) A PCR-based Linkage Map of Broccoli [Brassica oleracea(L.) var. italica] and Comparisons with Existing BrassicaMaps
Authors: Brown Allan , Ibrahim Khalid , Islam Sultana , Jeffery Elizabeth , Juvik John
Published: February 2019

A set of 216 PCR-based molecular markers was screened for polymorphisms using two morphologically dissimilar broccoli lines, `VI-158' and `BNC'. Fifty-nine of these markers, representing 69 detected polymorphisms and two morphological markers, were used to construct a genetic linkage map of broccoli [Brassicaoleracea (L.) var. italica] from a population of 162 F2:3 families generated from the cross between these two lines. Ten genetic linkage groups were generated that spanned a distance of 468 cM with an average interval width of 9.4 cm. This map represents the first combined SSR and SRAP map of Brassica oleracea. Comparisons are made to existing maps of Brassicanapus and to inter-specific maps of Brassicaoleracea. To our knowledge this is the first linkage map of broccoli [Brassicaoleracea (L.) var. italica] and should provide a useful tool for the genetic analysis of traits specific to the italica subspecies.
(465) Inhibitory Effect of Lingonberry (Vaccinium vitis-idaea L.) Extracts on Activator Protein-1, Nuclear Factor-KappaB, and Mitogen-activated Protein Kinases
Authors: Wang Shiow , Feng Ren-tian , Bowman Linda , Penhallegon Ross , Ding Min
Published: February 2019

The effects of lingonberry (Vaccinium vitis-idaea L.) extracts on activator protein-1 (AP-1), nuclear factor-kappaB (NF-κB), and mitogen-activated protein kinases (MAPKs) were evaluated. Pretreatment of JB6 P+ mouse epidermal cells with lingonberry extracts produced a dose-dependent inhibition of AP-1 and NF-κB induced by either 12-O-tetradecanoylphorbol-13-acetate (TPA) or ultraviolet-B (UVB) light. Lingonberry extracts blocked UVB-induced phosphorylation of MAPK family members ERK1, ERK2, and p38, but not JNK. Lingonberry extracts also prevented TPA-induced phosphorylation of ERK1 and ERK2. Results of soft agar assays indicated that lingonberry extracts suppressed TPA-induced neoplastic transformation of JB6 P+

cells in a dose-dependent manner. Lingonberry extracts also induced the apoptosis of human leukemia HL-60 cells in a dose-independent manner. These results suggest that ERK1 and ERK2 may be inhibited by lingonberries, which results in suppression of AP-1 and neoplastic transformation in JB6 P+ cells and causes cancer cell death by an apoptotic mechanism in human leukemia HL-60 cells.
(467) Anthocyanins as Primary Antioxidants in Black Raspberries
Authors: Tulio Artemio Z. , Ozgen Mustafa , Reese R. Neil , Schwartz Steven J. , Tian Qingguo , Stoner Gary D. , Miller A. Raymond , Scheerens Joseph C.
Published: February 2019

Anthocyanins in black raspberry extracts may play a key role in the regulation of oncogene expression in cancer cell cultures. Variations in anthocyanin levels of `Jewel', `Mac Black', and `Bristol' black raspberries grown at seven commercial farms in Ohio were investigated using HPLC and uv-vis spectrometry. Cyanidin-3-rutinoside (cy-3-rut) and cyanidin-3-(2G-xylorutinoside) (cy-3-2-xyl), the two major compounds present in all cultivars (≈2:1), were highly correlated with total anthocyanin contents. Sample variation in total anthocyanin, cy-3-rut, and cy-3-2-xyl levels was greater among commercial farms than among cultivars grown at the same location. The antioxidant activities of cy-3-rut, cyanidin-3-glucoside, cyanidin-3,5-diglucoside (cy-3,5-diglc), and pelargonidin-3-glucoside from purified extracts were determined using the free radical scavenging assays DPPH and ABTS, and the ferric reducing power assay FRAP. All pure anthocyanins showed strong antioxidant potentials except for cy-3,5-diglc. Cy-3-rut was identified and quantified as the dominant anthocyanin in black raspberries and was also the most potent antioxidant. Results suggest that anthocyanins, cy-3-rut in particular, may function as the primary antioxidants in black raspberries. Genetic and environmental variation in the anthocyanin contents necessitate characterization of the antioxidant and anthocyanin levels in fruits from any given source prior to measuring biological and medicinal activities.
(469) Replacing Cantaloupe with Orange-fleshed Honeydew Melon: Antioxidant Metabolism
Authors: Hodges D. Mark , Lester Gene E. , Meyer Robert D. , Willmets Vivian E. , Elliot Michele L.
Published: February 2019

Consumption of phytochemicals has been associated with reduced risks of human health dysfunctions such as cancers and heart disease. Such information has led to increased sales of fruits and vegetables. For example, in the United States, an estimated 23% increase in melon consumption (up to 13.2 lbs/capita/annum) has been recorded over 16 years. However, some health issues have been attributed to cantaloupe due to bacteria such as Salmonella attaching to inaccessible sites, such as the rind netting. Honeydew melons do not have a netted rind. The purpose of this study was to compare concentrations of antioxidants between cantaloupe and both green- and orange-fleshed honeydew melons during 14 days of storage to determine if orange-fleshed honeydew melon would represent a feasible alterative to cantaloupe to the increasingly health/food safety-conscious consumer. Cantaloupe (`Cruiser'; C), green-fleshed Honeydew (`HoneyBrew'; HB), and orange-fleshed Honeydew (`OrangeDew'; OD) melons were harvested in Texas at the beginning and at the end of the production season. β-carotene content was highest in OD, followed by C; no β-carotene was detected in HB. β-carotene levels did not change during storage. Phenolic levels increased in all three melon species during storage, whereas total ascorbate content declined in OD and in early harvest HB. Ascorbate peroxidase activities were lowest in OD, perhaps due to the lower ascorbate levels; little difference between the melon species in activities of the other ascorbate-associated enzymes were observed. Based on the phytochemicals measured in this study, choosing non-netted OD over netted C in order to reduce potential exposure to pathogens would not represent a less healthy food choice.
(473) Influences of Fertilizer Source and Insecticide Application on Phenolic Compounds in Pac Choi (Brassica rapa L.)
Authors: Zhao Xin , Carey Edward , Nechols James , Williams Kim , Wang Weiqun
Published: February 2019

Implications of dietary phenolic compounds for human health and disease prevention have been indicated by a body of literature. A greenhouse pot study was performed to investigate the impacts of fertilizer source and preventive insecticide application on phenolic compound levels in pac choi [Brassica rapa (L.) cv. Mei Qing]. A two-way randomized complete-block design with five replications was used in this experiment. Fertilizer source consisted of two levels: conventional fertilizer (pre-plant application of Osmocote slow-release fertilizer), and organic fertilizer (pre-plant application of vermicompost and fertigation with compost tea and fish emulsion). Insecticide application consisted of three levels: organic (pyrethrin) vs. conventional (permethrin), and a plain water control. At harvest, total phenolics and individual phenolic compounds in pac choi leaves (blades) were analyzed by Folin assay and HPLC, respectively. Head weight of pac choi was significantly higher under conventional fertilizer treatment, while it was not affected by insecticides. Total phenolic content of pac choi was significantly increased by organic fertilizer treatment. HPLC results indicated that organic fertilizer treatment resulted in significantly higher levels of individual phenolic compounds, including chlorogenic acid and ferulic acid. In contrast, preventive insecticide application showed little effect on the phenolics in pac choi. Correlation analysis excluded the influence of plant size (head weight) on phenolic content in pac choi. Differential N-forms, rates of nutrient release, and/or variable nutrient content in organic and conventional fertilizer treatments may contribute to elevated phenolic content in organically fertilized pac choi.
Native Variation in Bloom and Crop Density in Spur-type `Delicious' and Effect of Ethephon Applied in High Crop Years
Authors: Bukovac Martin J. , Hull Jerry , Sabbatini Paolo
Published: February 2019

For studies on blossom/fruit thinning in apple, tree selection is often based on uniformity of bloom/crop load, assuming that such trees exhibit greater uniformity to treatment. However, the literature is replete with data showing marked variation for a given treatment. We followed variation in bloom/crop density of spur-type `Delicious'/MM.106 and effect of ethephon applied in high crop years on return bloom/yield. Uniform trees (n = 95), under identical cultural practices, were selected for varying crop load. Return bloom, yield and fruit size were monitored over six years. General mean (X) for yield was 94 ± 25 kg/tree and bloom density, rated 1 to 10 (highest), was 5.4 ± 1.7. Annual yield deviated from X by +56 to –40% and bloom density by +49 to –42%. All trees were ranked (decreasing yield) and assigned to five percentile (PCTL) groups (1st, 81-100; 2nd, 61-80; 3rd, 41-60; 4th, 21-40; 5th, 0-20 kg/tree). Trees in each group were reassigned annually to the five PCPL groups for the next five years. Of trees in 1st PCTL (n = 19, X = 187 ± 10 kg/tree) in year one, 5, 5, 24, 0 and 63% placed in PCPL 1, 2, 3, 4, and 5, respectively, in year two. Of trees in 1st PCTL (5%) in year two, all placed in PCTL 2 in year three. Effect of ethephon [200 mg·L-1 at 3, 3 + 6, 3 + 6 + 9 weeks after full bloom (WAFB)] applied in on years to `Redchief', with strong alternate bearing, were evaluated for six years. Ethephon at 3 WAFB had no effect. Yield from multiple applications differed from control (NTC) in off years, but not from each other. Total yield (3 on + 3 off years) for the NTC and ethephon at 3 + 6 WAFB was similar (479 vs. 471 kg/tree). However, 64% of the total yield was produced in the on years and 36% in the off years in NTC vs. 56 and 44% in 3 + 6 WAFB, respectively.
Improving Eating Quality and Storage Life in Acorn Squash
Authors: Loy J. Brent
Published: February 2019

Acorn squash (Cucurbita pepo L.) is one of the three major classes of squash consumed in North America. Breeding improvements over the past 30 years have focused on more compact cultivars, earlier maturity, darker rind color, and powdery mildew tolerance (PMT). Our observations from sampling acorn squash from local supermarkets at different times during the year show that eating quality is highly variable, and most often, not acceptable. Our taste tests indicate that for acceptable eating, quality acorn squash should have °Brix of 10 or higher, flesh %DW above 16, and a smooth, nonfibrous texture. Most commercial cultivars fail to meet the above minimum criteria for quality. Proper harvest time is a major determinant of squash eating quality. To obtain adequate °Brix levels, squash should not be harvested until at least 50 days after pollination (DAP). If squash are harvested between 25 to 40 DAP and then stored for two or more weeks, °Brix levels may increase to acceptable levels, but some mesocarp reserves will be remobilized to developing seeds, reducing mesocarp %DW and lowering eating quality. A major goal of the squash breeding efforts at the University of New Hampshire has been to increase mesocarp %DW for obtaining more consistent eating quality. We have evaluated several experimental PMT hybrids during the past 5 years, and in some of these, flesh DW has averaged 17% or higher, and eating quality has been rated consistently very good. The adoption of better quality acorn cultivars together with implementing proper harvest times and storage conditions could appreciably increase per capita consumption.
Phosphorus Fertilizer Calibration Studies with Three Mustard Cabbage Varieties in Tropical Soils with Initial High P Levels
Authors: Valenzuela Hector , Goo Ted , Wall Dave , Corrales Roger , Migita Susan , Yamasaki Milton
Published: February 2019

Regulatory agencies are concerned about the high levels of P fertilizers used in some agricultural areas because of potential runoff to aquatic habitats. Farmers in Hawaii traditionally make blanket P applications even in soils high in P. Many farmers, especially those growing leafy crops, claim to observe responses to P, especially during the cooler winter months. A series of 15 field experiments were conducted over a 2-year period to evaluate the response of three mustard cabbage varieties to five P fertilizer rates across three locations in the state, and across several planting seasons. All experiments were conducted in soils with P levels that the University of Hawaii determined to be high in P. The experimental design for each experiment consisted of three commercial mustard cabbage varieties, and five P application rates (from 0 to 400 kg·ha-1 of TSP). Each plot consisted of a 3-m double-row, with plants spaced 15 cm within the row, and 30 cm between rows, with four replications per treatment. Each experiment thus consisted of 60 plots (three varietie × five P rate × four replications). After the initial P applications were made on each site, three consecutive crops were planted on the same site without making any additional P applications. Data collected included soil fertility prior to initiation and after experiment completion, tissue nutrient levels, plant height during crop establishment, and individual head weight of 20 plants per treatment. Our data show that even in soils with initial high levels of P, mustard cabbage responded to P applications, especially at high elevations and during the cooler months of the year. From this data we recommend that the University recalibrate its P fertilizer recommendations for leafy vegetable production in Hawaii.
New Sources of Lettuce Aphid Resistance in Lettuce
Authors: McCreight James D.
Published: February 2019

Lettuce aphid (Nasonovia ribisnigri Mosley) is a recent insect pest to lettuce (Lactuca sativa L.) production in the United States. The single dominant gene, Nr, conditions resistance to the lettuce aphid in Lactuca virosa accession IVT280 from The Netherlands and is available in a limited number of commercial lettuce cultivars. New and genetically unique sources of resistance are sought to broaden the genetic base for resistance to the lettuce aphid. About 1200 lettuce PI lines were evaluated for resistance to lettuce aphid in greenhouse tests using a strain of lettuce aphid obtained from commercial lettuce in Salinas Valley, Calif. In 2002, plants were individually infested with five 24-hour nymphs per plant (controlled protocol), and the numbers of aphids per plant were counted 10–14 days post-infestation (dpi). Beginning in 2003, plants were mass-infested (mass protocol) with nymphs and alates of various ages and numbers. Using the mass protocol, the number of aphids per plant 10–14 dpi were estimated and categorized using a 1–5 scale where 1 = 0 aphids per plant, 2 = 1–10 aphids per plant, 3 = 11–20 aphids per plant, 4 = 21–30 aphids per plant, and 5 = >30 aphids per plant. `Salinas' and `Barcelona' were included as susceptible and resistant controls, respectively. Most of the accessions were susceptible. A few accessions had a few plants with very low numbers of aphids after repeated infestation, but their progeny were susceptible. Two accessions were highly resistant: PI 491093, a Lactuca serriola accession from Turkey, and PI 274378, a L. virosa accession from France. Inheritance of resistance in these two accessions and their allelism to Nr remains to be determined.
The Study of Pollen Development in Nine Cultivars of Hazelnut (Corylusavellana)
Authors: Tiyayon Chantalak , Azarenko Anita Nina
Published: February 2019

Pollen development is an important event in plant reproduction. Hazelnut (Corylus avellana) male flower differentiation starts in summer and pollen shed is in the winter. Hazelnut pollen shed can vary up to 3 months between early to late flowering genotypes. Microsporogenesis and microgametogenesis of hazelnut is not well understood. Pollen development and differentiation of nine genotypes, representing early to late blooming cultivars from the National Clonal Germplasm Repository in Corvallis, Ore., were studied. Catkins were collected weekly from Aug. to Nov. 2002. Tissue sections were examined under the light microscope. Microsporogenesis was divided into five stages: archesporial cells, sporogenous cells and parietal layers, pollen mother cells (PMC), tetrads, and microspores. Microgametogenesis was distinguished between young pollen grains (uninucleate) and mature pollen grains (binucleate). On 4 Aug., cultivars were at different developmental stages of microsporogenesis. Early blooming cultivars had PMCs present. Later-blooming cultivars only contained archesporial cells. PMCs were present in all cultivars by 22 Aug. Microspores were observed on 26 Sept. in all cultivars. This study contributes to a better understanding of male gametophyte development in hazelnut, which has increased our ability to correlate hazelnut pollen development with bloom phenology.
Chemical Analysis of Cultivated Hypoxis hemerocallidea using Thin Layer Chromatography
Authors: Du Toit Elsa S. , Von Maltzahn Ilona , Soundy Puffy
Published: February 2019

Hypoxis hemerocallidea (African potato) is in high demand as a medicinal plant and therefore it is becoming scarce in its natural habitat. Thus, the objective of this study was to investigate the effect of cultivation practices on the active ingredients of the corm over a 12-month period. Different TLC (Thin Layer Chromatography) methods were also investigated when separating the different compounds. Plants were grown under a tunnel in plastic bags containing bark or sand growing media. The planted corms were treated with different fertigation frequencies and harvesting took place during four seasons. The harvested material was sliced, freeze-dried, and ground into a fine powder. Different solvents, namely methanol, acetone, and chloroform (chosen for their polarity) were used to extract the compounds from the ground material. The extracted residues were redissolved and spotted as thin streaks onto TLC plates. The TLC plates were then developed in different solvents and sprayed with different chemicals to bring out the different compounds found in the plant extract. Results on the TLC plates indicated that the amount of residue extracted with different solvents were significantly different. Therefore, TLC methods need to be considered when separating the different compounds. The growing media affected the amount of compounds produced from the corms during the 12-month period. The harvest season also played a role in the amount of active ingredients produced during the year. Therefore, cultivation practices influence the occurrence of active ingredients of H. hemerocallidea.
Carotenoid and Chlorophyll Pigments in Sweet Basil Grown in the Field and Greenhouse
Authors: Kopsell Dean A. , Kopsell David E. , Curran-Celentano Joanne
Published: February 2019

Therapeutic compounds in herbal crops are gaining recent attention. Sweet basil (Ocimumbasilicum L.) is a popular culinary herbal crop grown for both fresh and dry leaf markets. Recently, basil (unidentified cultivar) was shown to rank highest among spices and herbal crops for xanthophylls carotenoids. This class of carotenoids is associated with decreased risks of certain cancer and age-related eye diseases. The research goal for the current study was to characterize the concentrations of nutritionally important carotenoid pigments among popular varieties of basil. Eight cultivars of sweet basil (`Genovese', `Italian Large Leaf', `Nufar', `Red Rubin', `Osmin Purple', `Spicy Bush', `Cinnamon', and `Sweet Thai') were grown in both field and greenhouse environments and evaluated for plant pigments using HPLC methodology. Environmental and cultivar differences were significant for all of the pigments analyzed. `Sweet Thai' accumulated the highest concentrations of lutein, zeaxanthin, and beta-carotene carotenoids, while `Italian Large Leaf' had the lowest concentrations. Comparing the two environments, cultivar means for carotenoid and chlorophyll pigments were higher in the field environment when expressed on both a fresh and dry weight basis. Exceptions were found only for the purple leaf basils (`Osmin Purple' and `Red Rubin'). Positive and highly significant correlations existed between carotenoid and chlorophyll pigments in both environments. This study demonstrates that sweet basil can accumulate high levels of nutritionally important carotenoids in both field and greenhouse environments.
A New Dominant Trait of Natural Astringency Loss of Persimmon (Diospyroskaki Thunb.) Found in a Chinese PCNA `Luo Tian Tian Shi'
Authors: Yonemori Keizo , Ikegami Ayako , Eguchi Sai , Kitajima Akira , Kanzaki Shinya , Sato Akihiko , Yamada Masahiko
Published: February 2019

There is a non-astringent type of persimmon that loses its astringency naturally on trees, despite the absence of seeds. This type is called pollination-constant and non-astringent (PCNA)-type. PCNA-type was thought to have originated in Japan as a mutant that terminates tannin accumulation at an early stage of fruit development. This trait is confirmed to be recessive and the PCNA-type must be homozygous in all alleles. In fact, crossing among PCNA-type individuals yields only the PCNA-type in F1, while crossing between PCNA-type and non-PCNA-type yields only the non-PCNA-type. However, a new PCNA cultivar, `Luo Tian Tian Shi', was reported in 1982 to exist in Luo Tian County, China, and this PCNA-type seemed to have different mechanisms to be PCNA-type. Our previous report showed that a crossing between `Luo Tian Tian Shi' and Japanese PCNA `Taishu' yielded both PCNA-type and astringent-type in F1, indicating that the trait of PCNA in `Luo Tian Tian Shi' may be dominant. To confirm this hypothesis, we made crossings between `Luo Tian Tian Shi' and Japanese astringent-type `Yotsumizo' or `Iwasedo', and top-grafted these seedlings for earlier fruiting. As we had some fruits in a total of 25 F1 individuals last year, we investigated segregation of astringency among these individuals. We also confirmed the parental relationships of these progenies by analyzing several SSR markers. We confirmed the segregation of PCNA-type and astringent-type in F1. No mistake of artificial pollination was shown in all individuals by SSR markers. Thus, we concluded that the trait of astringency-loss in `Luo Tian Tian Shi' is dominant and the use of this cultivar as a parent will open a new window for breeding PCNA-type persimmon.
A Protocol to Quantify the Reactivity of Carbonate Lime for Horticultural Substrates
Authors: Huang Jinsheng , Fisher Paul R. , Argo William R.
Published: February 2019

Lime sources vary in their reactivity depending on particle size, surface area and crystalline structure, and chemical composition. Current horticultural practice for testing lime reactivity and the appropriate lime rate is through batch trials where lime is incorporated into growing media. Our objective was to test a laboratory approach that would provide a rapid analytical test on reactivity of lime sources, and could eventually be applied to measuring unreacted (residual) lime in container media. Four moles HCl was added to a lime sample, and the volume of CO2 released over time was measured in a burette. Three lime types were tested, including reagent grade CaCO3, and two pulverized dolomitic limestones used in horticultural media. 100% of CaCO3 reacted in less than a minute after acid addition, whereas only 79.8% and 49.5% of the two commercial lime samples had reacted after 10 minutes. The time required for 50% of the two commercial lime samples to react was 5 and 10 minutes, respectively, whereas it took 20 and 60 minutes, respectively, for 95% neutralization. Reaction rates in the laboratory test correlated with the time required to achieve a stable pH level when limes were incorporated into a peat substrate. The reagent-grade CaCO3 raised pH more rapidly (within 7 days) and to a higher level (maximum pH 7.5 at 9 g of lime per liter of peat) compared with the dolomitic lime sources. It may be possible to establish a lime reactivity index, for example, based on CO2 release after 10 minutes, and thereby provide a rapid screening of limes. Further gasometric analysis of lime types used in horticultural substrates is therefore needed.
Comparison of First- and Second-Year Growth between Container-grown `Autumn Blaze' Maple Trees
Authors: Litus Greg , Klett James
Published: February 2019

In May 2004, at the request of local nursery owners, young Acer ×freemanii 'Autumn Blaze' (Autumn Blaze maple) trees previously grown in a number 20 (#20) container pot-in-pot (PIP) system were planted at the Colorado State University Horticultural Farm alongside similarly sized trees field grown, balled and burlapped (B&B). These trees were planted using methods recommended by the International Society of Arboriculture with half receiving 30% by volume soil amendment consisting of Organix compost mixed with the native soils. In addition, five trees grown for one year using the #20 PIP container system were maintained a second year in the same containers and compared to five trees transferred to #45 containers. After one season, the PIP-grown trees showed significantly more shoot growth and increased trunk caliper than the B&B trees. The application of amendments had no effect on the growth for either the B&B or PIP trees. Trees maintained in PIP containers for a second year had similar growth regardless of the container size.
Effect of Fall Fertilization on Freeze Hardiness of Deciduous versus Evergreen Azaleas
Authors: Henning Frank P. , Smalley Timothy J. , Lindstrom Orville , Ruter John
Published: February 2019

This experiment compared the effect of fall fertilization on freeze hardiness of evergreen vs. deciduous azaleas (Rhododendron). Beginning in Spring 2003, a 2 × 3 factorial experiment was conducted in Athens, Ga., on container plants grown outdoors under nursery conditions involving two taxa (R. canescens and R. ×satsuki `Wakaebisu') and three fall fertigation regimes (Aug.–Sept., 75 mg·L-1 of N; Aug.–Nov., 75 mg·L-1 of N; and Aug.–Nov., 125 mg·L-1 of N). On 15 Nov. and 17 Dec. 2003 and 16 Jan., 18 Feb., and 19 Mar. 2004, plant stem tissue was harvested and exposed to 10 progressively lower temperature intervals between –3 °C and –30 °C under laboratory conditions in order to estimate azalea freeze hardiness. Freeze hardiness was affected by fertilizer and taxa treatments, but there were no significant interaction effects in this study. The timing of freeze hardening was not significantly different among the two species over time, and the fall fertilizer treatments did not affect the timing of hardening. Compared to the industry standard (75 mg·L-1 of N, Aug.–Sept.), R. canescens that received extended fertilization at the high rate (125 mg·L-1 of N, Aug.–Nov.) was less freeze hardy in November, December, and January, and R. ×satsuki was less freeze hardy in December. However, when compared to the industry standard, the low rate of extended fertilization (75 mg·L-1 of N, Aug.–Nov.) did not affect azalea freeze hardiness.
Transport of Cross-pollen by Bumblebees in a Rabbiteye Blueberry Planting
Authors: Brevis Patricio A. , NeSmith D. Scott
Published: February 2019

Blueberries are bee-pollinated species that benefit from cross-pollination. Cross-pollination is particularly critical for optimum fruit set of rabbiteye blueberries (Vaccinium ashei Reade) because of their limited degree of self-fertility. In order to determine if the failure to set adequate commercial fruit loads is due to a lack of cross-pollination, research was needed to establish how much out-crossing rabbiteye blueberry pollinators actually do. A novel method was developed to identify pollen grains on the bodies of bumblebees by cultivar. The technique discriminates between two cultivars, based on differences in pollen diameter. Bumblebees were collected in a plot composed of blueberry plants of the cultivars Brightwell and Climax since these cultivars produce pollen of different size. Pollen loads of bumblebees contained low proportions of cross-pollen regardless of the cultivar they were visiting. Data suggest that inadequate levels of cross-pollination play a major role in low fruit set problems of rabbiteye blueberry. The composition of bees' pollen load changed with the phenology of the crop. The greatest likelihood for cross-pollination occurred around the time of maximum bloom overlap. Bumblebees foraging on `Brightwell' flowers carried more total blueberry pollen and a higher proportion of self-pollen than those visiting `Climax'. This may be due to differences in pollen release between flowers of these two cultivars.
Sensory Evaluation of Six Varieties of Organically Grown Edamame-type Soybean
Authors: Wszelaki Annette , Delwiche Jeannine , Walker Sonia , Liggett Rachel , Miller Sally , Kleinhenz Matthew
Published: February 2019

Consumer testing and descriptive analysis were conducted on six commercial varieties of organically grown edamame-type soybean. In the affective tests, 54 panelists rated pods and beans for appearance, and beans for aroma, taste, texture, aftertaste, and overall acceptability on a 9-point hedonic scale and willingness to buy on a 9-point category scale. `Sayamusume' was liked significantly better than all varieties except `Kenko' and `Sapporo Midori' for taste. `Kenko' was also rated higher than `Sapporo Midori', `Misono Green', and `Early Hakucho' for pod appearance. `Misono Green' texture was liked less than that of all other varieties except `White Lion'. In the descriptive analysis, 10 trained panelists rated the beaniness, sweetness, nuttiness, and chewiness of the same six varieties. `Kenko' rated significantly sweeter than all other varieties except `Sapporo Midori'. `White Lion' rated as significantly lower in chewiness than all other varieties. Beaniness and nuttiness could not be consistently differentiated among varieties. The data suggest that consumer liking of bean taste varies, though subtly, among the six edamame varieties tested here and that preferences may differ with gender. Results from descriptive analysis also suggest that panelists relied on texture (i.e., chewiness) and sweetness to differentiate between varieties. These results are particularly important in overall product quality management strategies as chewiness and sweetness may be influenced by production practices and harvest timing.
Wool and Hair Waste as Nutrient Source for High-value Crops
Authors: (Zheljazkov) Valtcho Jeliazkov , Stratton Glenn , Pincock James , Butler Stephanie , Jeliazkova Ekaterina
Published: February 2019

One small-plotfield and five container experiments were conducted to evaluate sheep wool-wastes and human hair-wastes as soil amendments and nutrient sources for high-value crops. Overall, the wool-waste or hair-waste addition to soil: 1) increased yields from basil, garden sage, peppermint, valerian, thorn apple, marigold, foxglove, and swiss chard; 2) increased the amount of secondary metabolites (such as essential oils and alkaloids); 3) increased NH4-N and NO3-N in soil; 4) increased total N (and protein) content in plant tissue; 5) did not affect soil microbial biomass; and 6) decreased mycorrhizae colonization of plant roots. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyses indicated that some of the wool and hair in soil from the container and field experiments (after two field seasons and several harvests) retained its original structure, retained a significant amount of S and some N, and was not fully decomposed. Our results indicate that single addition of wool or hair-waste of 0.33% by weight to soil would support two to five harvests or crops, without addition of other fertilizers, and may improve soil biological and chemical characteristics.
Learning by Building: How a Landscape Construction Studio Enriches Horticultural Education
Authors: Spafford Anne
Published: February 2019

The Department of Horticultural Sciences at North Carolina State University began offering landscape horticulture students a construction studio in 2002. This unique studio engages students in experiential learning (hands-on) and service learning (client-based) projects while simultaneously applying knowledge they have gained during their university education. Three years later, the Landscape Construction Studio is a model course that pushes students to design creatively, while providing a practical foundation in how ideas transition from paper to reality. Projects embody several learning objectives, including fostering exploration and discovery while raising students' awareness of strengths and limitations of traditional and nontraditional construction materials. In addition, the studio enables the elimination of students' tendency to compartmentalize course work, and encourages students to broaden their understanding and appreciation of the world around them. A typical semester incorporates several smaller projects that introduce students to a variety of materials and lessons in construction methodologies. Projects increase in size and complexity over the course of the semester, leading to a comprehensive landscape design and installation project in which students experience the entire design process. Through this final project, students see how information gained from other horticultural and general classes are applied in landscape design. This presentation will discuss the importance of incorporating experiential learning components to horticultural courses, and the pros and cons of service learning projects. Presentation of best management practices will stimulate discussion among the audience.
Invasive Plant Species: Consumer Awareness, Knowledge, and Expectations
Authors: Kelley Kathleen M. , Stumpf Janine R. , Sellmer James C. , Bates Ricky M.
Published: February 2019

Consumers were surveyed at the 2004 Philadelphia Flower Show in Philadelphia, Pa. from 8–10 Mar., to quantify their attitudes and behaviors towards invasive plant species and the potential problems associated with purchasing and planting invasives in the landscape. A majority of the 341 participants (81.5%) was aware that non-native exotic plants were used in the landscape and that these plants may be invasive in natural areas. Less than half (40.1%) acknowledged owning plants that were considered invasive, while one-third (33.5%) did not know. Less than half (41.3%) believed that laws should be passed to prevent sale of non-native exotic plants, while 27.8% believed that laws should be passed to allow sale of only native plants in their area. Three distinct consumer segments were identified using cluster analysis: “Invasive savvy,” participants knowledgeable about invasives and interested in alternative species; “Invasive neutral,” participants neutral in their decision to purchasing alternatives to invasive plants and price sensitive in regard to paying more for plants tested for invasiveness; and “Invasive inactive,” participants opposed to purchasing genetically modified plants or those bred to be seedless. Survey results indicated that media sources (e.g., television and newspapers/magazines/books) would be effective for educating consumers about potential problems associated with invasive species in the landscape.
Plant Science Graduate Students: Demographics, Research Areas, and Recruitment Issues
Authors: Darnell Rebecca , Cheek Jimmy
Published: February 2019

Graduate student enrollment in the plant sciences has decreased over the past several years, and there is increasing interest in recruitment/retention strategies. Before successful strategies can be implemented, however, the status of current plant science graduate programs needs to be determined. Survey data on graduate student demographics, research area, support levels, current recruitment strategies, and career opportunities were collected from 23 plant science graduate programs. Overall, 55% of graduate students in plant sciences were male and 45% were female; about 60% were domestic and 40% were international. Cellular/molecular biology and breeding/genetics were the two disciplines that had the greatest number of graduate students and the greatest number of job opportunities. Most programs cited financial support as the biggest obstacle to recruitment. However, stipend number, the guarantee of multiple years of support, the funding of tuition waivers, and health insurance costs also impact student numbers. As more of these costs are shifted to faculty, there appears to be an increasing inability and/or reluctance to invest grant funds (which support 60% of the plant science graduate students) in graduate student education. These data suggest that the decline in plant science graduate student enrollment may be due to shifting of more of the total cost of graduate training to faculty, who may be unable/unwilling to bear the cost. There is also a clear shift in the research focus of plant science graduate students, as postdoctoral and career opportunities are weighted toward molecular biology/genetics, leaving the more applied plant science areas particularly vulnerable to low graduate enrollment.
Effect of Plant Architecture on the Performance of Two High-chill Pear Cultivars
Authors: Yadav Ashish , Yadav Anand Krishna , Bist Lila Dhar
Published: February 2019

Pear growing in subtropics began with the advent of low-chill pears, but their fruit quality is inferior to high-chill European/Oriental pears. Thus, the best way to produce high-chill pears in subtropics is by topworking them on the low-chill pears. To attain this, pruned wood with spurs of `Doyenne du Comice' (DCP) and `Victoria pear' (VP) cultivars were collected in January from Hort Expt Center Chaubatia, India (6825'ASL), and tongue grafted on low-chill `Pant Pear-18' (PP18). The grafting was at different heights on trees using 25-cm and 1-m long stocks on Tatura trellis-trained PP18 trees at the Hort. Research Center, Pantnagar (760' ASL). More than 90% grafts succeeded and both DCP and VP produced high quality fruits, but DCP grafts had an edge over VP scions. Both high-chill cultivars topworked on 25-cm stocks had better grafting success (95%) than the scions topworked on 1-m stocks (92%). The increase in topworking heights on stock trees reduced the floral spur numbers in both scions grafted on 25-cm stocks, but not on the scions grafted on 1-m stocks. With the incremental height of topworking irrespective of the length of stocks, the percentage of fruit set was curtailed by 28% and 12% for the DCP and VP scions, respectively. Irrespective of the topworking heights and stock lengths, the fruit yield for DCP (12.5 lbs/tree) was markedly higher than for VP (7.9 lbs/tree). Fruit quality attributes judged by organoleptic testing, TSS, total sugars, acidity, and ascorbic acid, were better for both DCP and VP than for PP18 and other local pear cultivars. The reuse of previous year's scions topworked even after artificial chilling and/or GA3 application to supplement chilling exhibited no fruiting advantage over the grafting using fresh scions.
(21) Quality Factors Important to Navel Orange Taste as Influenced by Maturation and Handling
Authors: Obenland David , Neipp Paul , Sievert Jim , Collin Sue , Arpaia Mary Lu
Published: February 2019

Maturity standards that determine when navel oranges can be harvested in California are currently based upon the ratio of soluble solids content (SSC) to titratable acidity (TA) and the rind color of the fruit. These standards may be inadequate to describe the quality of the fruit, which is important given the increased competition from other commodities in the marketplace and declining consumption of fresh citrus. To reevaluate the basis of the maturity standard, navel oranges were harvested at intervals throughout the season and evaluated for SSC, TA, juice ethanol concentration, percent juice, peel coloration, and sensory characteristics. Three varieties of navel oranges, representing early-, mid- and late-season maturities, were used. SSC: TA ratios averaged 6.3 at the beginning of the season and steadily increased to 23.4 at the end of the season. Changes in the hedonic rating, or likeability of the fruit taste as rated by the sensory panelists, were closely related to the SSC: TA ratio and ratings of sweetness and tartness. These relationships showed a similar pattern for all of the navel varieties. A hedonic rating of 6 (like slightly) was not reached until the SSC: TA ratio exceeded the current legal minimum of 8:1, suggesting that the standard should be raised. Juice ethanol levels and percent juice did not have any apparent influence on the sensory ratings. Fruit that were run over a packing line and waxed developed higher amounts of ethanol during storage than control fruit but did not differ substantially from them in hedonic rating.
(22) Evaluation of Postharvest Texture and Weight Loss in Apple Fruits by Destructive and Nondestructive Measurements
Authors: Choi Sun Tay , Abbott Judith , Chang Kyu Seob , Kim Ji Gang , Lim Chae Il
Published: February 2019

The relation between sensory and instrumental measurements of apple texture was investigated to find an effective postharvest texture measurement method of apple. Then nondestructive evaluation of texture and weight loss using NIR was conducted. `Gala' and `Fuji' apples were sampled during storage at 20 °C with 80% to 85% relative humidity. Instrumental measurements included penetration, compression, and bending tests with a texture analyzer, and sensory attributes were finger firmness, hardness, crispness, and mealiness. The penetration test was more effective for postharvest texture measurement than compression and bending tests in the correlation between sensory texture and instrumental measurement. As texture evaluation parameters, elastic modulus (slope before rupture point) and work (area to penetrate) of penetration test were more sensitive than maximum force. Maximum force, generally used as the parameter for texture evaluation, had a little problem under influence of weight loss in `Fuji'; however, elastic modulus and work could detect the texture change of apple under influence of weight loss as well as softening. In the investigation of possibility of nondestructive evaluation using NIR of texture, the MLR analysis for elastic modulus determination of penetration test showed good correlation (R = 0.82, SEP = 2.66) in combination of two cultivars. Also, in the weight loss evaluation, MLR analysis showed the prediction correlation of 0.79 and SEP 1.08 in combination of two cultivars. These results showed the possibility of nondestructive evaluation using NIR of postharvest texture and weight loss.
Antioxidation Capacities of Extracts from Green, Purple, and White Asparagus Spears Related to Polyphenol Concentration
Authors: Maeda Tomoo , Kakuta Hideo , Sonoda Takahiro , Motoki Satoru , Ueno Reiichiro , Suzuki Takashi , Oosawa Katsuji
Published: February 2019

The antioxidation capacities of green `Welcome', green and white `Gijnlim', and purple `Purple passion' asparagus spears were evaluated. Analyses of rutin and total polyphenols, and assays of DPPH radical absorbing and low-density lipoprotein (LDL) antioxidation were conducted. Varietal differences associated with the colors of spears were observed both in the amounts of rutin, total polyphenols and in DPPH radical absorbing activities, although not in LDL antioxidation activities. DPPH radical absorbing activities seemed to be affected by both rutin and other polyphenolic compounds. However, LDL antioxidation activities were likely to be influenced more by other polyphenolic compounds than by rutin. Total polyphenol content showed a fairly close relationship with rutin content, DPPH radical absorbing activity and LDL antioxidation activity. To determinate total polyphenol content using the Folin–Denis' method seemed to be useful for selecting the breeding lines that show high antioxidative capacities.
Clonally Propagated and Seed-derived Papaya Orchards: I. Plant Production and Field Growth
Authors: Fitch Maureen M.M. , Moore Paul H. , Leong Terryl C.W. , Akashi Leslie Ann Y. , Yeh Aileen K.F. , White Susan A. , Cruz Amy S. Dela , Santo Lance T. , Ferreira Stephen A. , Poland Leslie J.
Published: February 2019

Papaya seedlings segregate for sex expression as females or hermaphrodites. Typically only hermaphrodite fruit are marketed in Hawaii. The agronomic practice of growing multiple seedlings that are later thinned to a single hermaphrodite tree is wasteful of seed, labor, and resources, especially when seed is costly. We compared growth of plants propagated by the clonal methods of micropropagation or rooting vegetative cuttings versus plants initiated as seedlings and transplanted. The seedlings were either single-planted hermaphrodites as identified by the polymerase chain reaction (PCR) or multiple-planted, thinned seedlings. The experiments were carried out in three different locations on two islands in Hawaii. Clonally propagated plants were significantly shorter than seedlings and bore flowers earlier and lower on the trunk at all locations. Stem diameter differences were not significant even though plant size was different at planting time. Percentage of trees in bud varied significantly in the third month after transplanting when about 90% of the rooted cuttings and large micropropagated plants had formed flower buds while only one multiple-planted seedling developed a bud. Overall, the clonally propagated plants were more vigorous and earlier bearing than were the seedling plants. There is good potential for adoption of clonal propagation when production becomes efficient enough to compete in price with the current practice of over planting and thinning.