bluuebunny/crossref_metadata_2025 huggingface dataset:
A Strip-tillage System for Snap Beans
Authors: Masiunas John , Bottenberg Harry , Eastburn Darin , Eastman Catherine
Published: February 2019

Our previous research found that snap bean yields were reduced in cropping systems with cereal rye residues. Strip-tillage may overcome the yield reductions while providing the environmental advantages of high residue systems. An experiment was established at Champaign, Ill. `Wheeler' cereal rye was seeded in September at 110 kg·ha–1. The treatments were 1) conventional tillage with trifluralin, 2) rye without strips, 3) rye with fall-established strips, and 4) rye with spring-established strips. The rye was mowed 1 week before planting the snap beans. The spring strips were established in solid-seeded rye using a no-till planter, modified with extra culvers. It was difficult to maintain the fall-established strips after mowing. Weed control in the strips was problematic. Yields and insect populations were also determined.
Evaluation of Two Visual Scales to Estimate European Corn Borer Ear Feeding Damage in Sweet Corn
Authors: Warnock Daniel F. , Davis David W.
Published: February 2019

The germplasm evaluation techniques in resistance breeding programs may improperly characterize insect damage. For example, the relationship between economic damage levels and biological damage levels may not be linear as some techniques assume. Most commercial sweet corn hybrids are highly susceptible to European corn borer (ECB), Ostrinia nubilalis Hübner, ear feeding. Genotype variation for ECB damage in our breeding program traditionally has been identified by using a 1 (no damage) to 9 visual rating scale that combines damage levels, damage site on the ear, and the economic consequences of ECB feeding for the processing industry. An alternative 1 to 5 scale based solely on a visual percentage assessment of ear feeding damage was developed and compared to the traditional scale. Seven entries, including moderately resistant and susceptible hybrids and inbred lines of the ECB ear resistance breeding program, were evaluated with both scales in 1994 and 1995 at two locations. Inbred MN3002, Hybrid MN3004, `Apache', and `More' had lower mean damage ratings (3.4, 3.4, 3.6, 3.8, traditional vs. 2.4, 2.2, 2.2, 2.3, alternative, respectively) than `Jubilee', Inbred W182E, and Inbred MN3003 (5.3, 5.6, 7.3, traditional vs. 3.3, 3.0, 4.2, alternative, respectively). Thus, four entries were classified as moderately resistant (3.0 to 4.0 traditional vs. 2.0 to 3.0 alternative) and three entries were classified as susceptible (>4.0 traditional vs. >3.0 alternative). Individual entry ranks varied by scale, but this did not alter resistance classifications. Although the nine traditional ratings were based on economic consequences and the five alternative ratings were based strictly on feeding levels excluding damage location, both scales effectively identified genotypes historically classified as moderately resistant and susceptible. The value of scales is often questionable for many situations and should be considered prior to evaluation.
Isozyme Inheritance and Variation in Actinidia
Authors: Huang Hongwen , Dane Fenny , Wang Zhongzen , Jiang Zhengwan , Huang Rehuang , Wang Shengmei
Published: February 2019

Isozyme inheritance and variation in Actinidia was investigated using 23 enzyme systems. Ten isozyme loci from six enzyme systems, Acp-2, Est, Prx-1, Prx-2, Prx-4, Prx-5, Pgi-2, Pgm-2, and Tpi, were found to be inherited as single Mendelian genes in families of two interspecific crosses. Disomic inheritance detected at ten loci in progenies of a cross between the hexaploid A. deliciosa × diploid A. chinensis, provided convincing evidence that A. deliciosa is an allohexaploid. Allelic segregation for tetrasomic inheritance at ten isozyme loci was demonstrated in the progenies of a cross between the tetraploid A. chinesis × diploid A. eriantha, a result suggesting the autotetraploid origin of the tetraploid A. chinensis which apparently originated from its diploid ancestor A. chinensis. A high level of isozyme variation and heterozygosity were observed in the 22 cultivars and 56 plants of 28 Actinidia taxa. Allozyme phenotype can be used effectively for cultivar identification.
Identification of RAPD Markers Linked to Major Gene for Indeterminate Growth Habit using Bulked Segregant Analysis in Common Bean Cross
Authors: Park S.O. , Bokosi J.M. , Coyne D.P.
Published: February 2019

Plant growth habit is an important trait. Our objective was to identify RAPD markers linked to major gene for indeterminate growth habit using bulked segregant analysis in an F2 population from a bean cross Chichara (indeterminate growth habit × PC-50 (determinate growth habit). A total of 132 RAPD primers (600 RAPD primer screened) showed polymorphisms between bulked DNA derived from indeterminate and determinate plants. All markers showed coupling linkage with indeterminate growth habit. RAPD markers of A-8, A-17, C-7, C-15, D-4, D-5, F-6, F-16, G-9, H-3, H-20, and I-7 were 2.2 cM distant from the gene for indeterminate growth habit. Markers of B-7, B-16, B-17, C-8, E-1, F-1, F-20 and H-l9 primers were 4.6 cM distant from the gene for indeterminate growth habit.
Identification of RAPD Markers Linked to Major Genes for Common Bacterial Blight (CBB) Resistance Using Bulked Segregant Analysis in a Tepary Bean Cross
Authors: Park S.O. , Dursun A. , Coyne D.P. , Jung G.
Published: February 2019

Common bacterial blight (CBB), incited by Xanthomonas campestris pv. phaseoli (Xcp), an important disease in common bean (Phaseolus vulgaris L.) Tepary bean (P. acutifolius A. Gray) is of interest to bean breeders because of resistance to CBB. Our objective was to identify RAPD markers linked to major genes for CBB resistance using bulked segregant analysis in an F2 population from a tepary bean cross CIAT640005 (R) X Nebr#4B (S). A total of 57 RAPD primers (602 RAPD primers screened) showed polymorphisms between bulked DNA derived from R and S CBB plants. All markers showed coupling linkage with CBB resistance. A good fit to a 3:1 ratio of bands for presence and absence using 11 RAPD primers was observed in 77 F2 plants. Markers of U-15 and L-7 primers were 2.4 cM distant from the gene for resistance to Xcp strain LB-2. RAPD markers of U-10, U-20, S-12, Y-4, F-13, P-6, Q-1, and Q-ll primers were 2.4 cM distant from the gene for resistance to Xcp strain SC-4A. RAPD markers of IJ-15 and L-7 primers were 8.4 cM distant from the gene for resistance to Xcp strain EKl l. The tepary RAPD linkage group includes three molecular markers and three genes for resistance to Xcp strains EK-l l, LB-2, and SC-4A and spans a length of 19.2 cM. This data supports the presence of Xcp races.
Genetic Analysis of Salt Tolerance during Vegetative Growth in Tomato
Authors: Foolad M.R.
Published: February 2019

Breeding for salt tolerance in tomato (Lycopersicon esculentum Mill.) has been restricted by insufficient knowledge of the genetic control of tolerance. The genetic basis of salt tolerance during vegetative growth was investigated by growing a salt tolerant (PI174263) and a salt sensitive tomato cultivar (UCT5) and their F1, F2, and backcross progeny in saline solutions with electrical conductivity of 0.5 (control) and 20 dS·m–1 (salt-stress). The relative salt tolerance of each generation was determined as the percentage of growth (i.e., dry matter production) under salt-stress relative to growth under control conditions. In all generations, shoot growth was significantly reduced by salt-stress. The reduction was largest in UCT5 (56.1%) and smallest in the F1 (27.4%) followed by PI174263 (32.3%). Analysis of the absolute and relative growth under salt-stress indicated that genes contributing to vigor might be different from genes conferring tolerance. Generation means analyses of the absolute and relative growth indicated that the majority of the genetic variation among generations were due to simple (additive and dominance) genetic effects; nonallelic interactions, although significant, were far less important. Partitioning of the total genetic variance by weighted least square regression analysis and variance component analysis indicated that 88% or more of the variation were due to additive genetic effects. A moderate estimate of narrow sense heritability (0.49 ± 0.09) was obtained for shoot dry weight under salt-stress treatment. The results indicate that tomato salt tolerance during vegetative growth can be improved by breeding and selection.
The Expression of Nonacclimated Freezing Tolerance and Acclimation Capacity in Progeny Derived from Somatic Hybrids of Solanum tuberosum and S. commersonii
Authors: Chen Yu-Kuang , Bamberg John B. , Palta Jiwan P.
Published: February 2019

Tetraploid somatic hybrids between S. tuberosum (tbr) and S. commersonii (cmm) have been produced to incorporate desirable traits such as cold hardiness from cmm into cultivated potatoes. While nonacclimated freezing tolerance (NA) of these somatic hybrids were as low as tbr fusion parent, their acclimation capacity (ACC) approximated that of the parental mean. In order to further explore the potential of using these somatic hybrids in breeding programs and to examine the segregation of genes conferring NA and ACC in somatic hybrids, progenies have been developed from either selfing somatic hybrids or crossing them with a tuberosum breeding line, Wis 231. In total, 48 selfed and 6 backcross progenies were characterized for the expression of NA and ACC. The NA derived from cmm was still poorly recovered in both sets of progenies. However, ACC did show some variation ranging from the level of sensitive fusion parent to that of the selfed parent, HA 26-5. None of the progeny had ACC as high as their cmm parent. Our results suggest that the expression of NA was suppressed by the cold sensitive genome of tbr. Thus, ACC is the form of cold tolerance from cmm, which appears to be most easily accessed though these somatic hybrids.
Sugary enhancer1 (se1) Gene Endosperm Dosage and Sweet Corn Carbohydrate Content
Authors: Kurilich Anne C. , Wang Shyh-Shyan , Juvik John A.
Published: February 2019

Inbreds IL451b sugary1 (su1) and IL678a su1 isogenic for the sugary enhancer1 (se1) gene mutation were used to analyze the relationship between se1 gene dosage and endosperm sugar content. Each line was self-pollinated and reciprocal crosses were made between the isolines of each genotype to produce se1 gene dosages of 0, 1, 2, and 3 in the triploid endosperm. Ears were harvested at 15, 18, 21, 24, 27, and 45 days after pollination (DAP). Whole kernels were freeze-dried, ground into powder, and stored at –80°C until subsequent chemical analyses. Sucrose, glucose and fructose were analyzed using high-pressure liquid chromatography (HPLC), the results of which indicated a significant increase in kernel sugar content when the se1 allele is homozygous.

Prediction accuracy as affected by the length of the subperiod (k).

Sucrose content at 21 DAP (typical maturity for harvesting) was observed to increase in the IL451b and IL678a backgrounds from zero to three doses of se1 by 65% and 18% respectively, indicating that this mutation varies in its expression in different genetic backgrounds. Associations between kernel phytoglycogen and starch content and se1 gene dosage are presented. The biochemical lesion associated with the se1 gene product is discussed.
Onion Umbel Tissue Induces Threefold Greater in Vitro Antiplatelet Activity than Onion Bulb Tissue
Authors: Goldman I.L.
Published: February 2019

Onion consumption promotes cardiovascular health by inhibiting platelet activity. Bulbs are the only onion plant organ thus far examined for antiplatelet activity. The inbred line W420B was grown in replicated field trials at four United States locations in 1994. At bulb maturity, samples from each plot were tested for antiplatelet activity using human blood plasma. The remaining portion of the bulbs from each plot was stored, vernalized, and planted in a breeding nursery in 1995. Umbels were excised from 20 randomly selected plants when >50% of the flowers had opened and tested for antiplatelet activity. Inducement of antiplatelet activity was 336% higher by onion umbels than by bulbs. This finding indicates onion umbels are a more potent source of antiplatelet activity than onion bulbs. In addition, these data suggest that onion umbels may be a richer source of bioactive organosulfur compounds in onion tissue.
Unilateral Incompatibility as a Major Cause of Skewed Segregation in the Cross between Lycopersicon esculentum and L. pennellii
Authors: Foolad M.R.
Published: February 2019

Skewed segregations are frequent events in segregating populations derived from different interspecific crosses in tomato. To determine a basis for skewed segregations in the progeny of the cross between Lycopersicon esculentum and L. pennellii, monogenic segregations of 16 isozyme loci were analyzed in an F2 and two backcross populations of this cross. In the F2, nine loci mapping to chromosomes 1, 2, 4, 9, 10, and 12 exhibited skewed segregations and in all cases there was an excess of L. pennellii homozygotes. The genotypic frequencies at all but one locus were at Hardy–Weinberg equilibria. In the backcross populations, all except two loci exhibited normal Mendelian segregations. No postzygotic selection model could statistically or biologically explain the observed segregation patterns. A prezygotic selection model, assuming selective elimination of the male gametophytes during pollen function (i.e., from pollination to karyogamy) adequately explained the observed segregations in all three populations. The direction of the skewed segregations in the F2 was consistent with that expected based on the effects of unilateral incompatibility reactions between the two species. In addition, the chromosomal locations of five of the nine markers that exhibited skewed segregations coincided with the locations of several known compatibility-related genes in tomato. Multigenic unilateral incompatibility reactions between L. esculentum pollen and the stigma or style of L. pennellii (or its hybrid derivatives) are suggested to be the major cause of the skewed segregations in the F2 progeny of this cross.
`Excel', `Early Scarlet' and `Arkansas Blackeye #1': New Southernpea Varieties
Authors: Morelock T.E. , Motes D.R. , Gonzalez A.R.
Published: February 2019

Southernpea (Vigna unguiculata) is an important crop in the southern United States. The Arkansas Agricultural Experiment Station announces the release of three varieties. `Excel' produces a compact bush plant, from 45–60 cm tall with no basal runners. Pods are deep purple, 20–25 cm long and shell easily at the green mature stage. Flowering and fruiting are concentrated, with the pods produced at the top of the plant on medium-length peduncles. Seed has a bright pinkeye and is similar in size to pinkeye purple hull BVR but matures 3–4 days earlier. `Early Scarlet' produces a medium sized plant, from 60–75 cm tall with no basal runners. Pods are light red, 20–25 cm long and shell easily at the green mature stage. Flowering and fruiting are concentrated at the top of the plant with pods produced on medium-length peduncles. Seed has a light pinkeye and is similar in size to `Pinkeye Purple Hull BVR' but matures 2–3 days earlier. `Arkansas Blackeye #1' produces a bush plant, from 50–65 cm tall with no basal runners. The pods are silver, 20–25 cm long and shell easily. Flowering and fruiting are concentrated with the pods produced in the top of the plant on medium-length peduncles. Seed has a distinct medium-sized blackeye and the seed are very similar in size, type and eye pattern to `California #5 Blackeye'. Maturity is normally 2–3 days earlier than `Pinkeye Purple Hull BVR'.
Effect of Medium and Genotype on the in Vitro Growth of Alstroemeria
Authors: Chiari Alessandro , Bridgen Mark P.
Published: February 2019

Three Alstroemeria genotypes—A30, ER292, and 16-1-2—developed at the Univ. of Connecticut were grown in vitro on two media: Murashige and Skoog (MS) basal medium and Alstroemeria medium (ALA). Each medium had four levels of 6-benzylaminopurine (BA) added: 0, 9, 18, and 36 μm. Alstroemeria rhizomes initially containing one bud were cultured on the 24 treatments for 12 weeks with transfers onto fresh medium at 4 and 8 weeks. At each transfer and at the end of the experiment plants were scored for the number of shoots produced, number of new buds, fresh weight, and presence of roots. No difference was observed between the MS and ALA media. No interaction was found between medium and hormone concentration. BA inhibited the formation and growth of roots that were observed only in the control without BA. The control was different from 9, 18, and 36 μm BA for the number of buds produced, number of shoots and fresh weight while no differences were observed between the various concentrations of BA. ER292 gave the highest yields in number of buds, shoots and fresh weight of all the genotypes.
Histological Comparisons of Shoot-forming and Nonshoot-forming Somatic Embryo Variants of Sweetpotato (Ipomoea batatas (L) Lam)
Authors: Padmanabhan Kalavathy , Cantliffe Daniel J. , Harrell Roy C. , McConnell Dennis B.
Published: February 2019

A comparison of external morphology captured via a computer vision system and a study of internal anatomy of sweetpotato somatic embryos identified five different major morphological variants among torpedo and cotyledonary stage embryos. These included 1) Perfect Type, 2) Near Perfect Type, 3) Limited/No Meristematic Activity Type, 4) Disrupted Internal Anatomy Type, 5) Proliferating Type. Perfect and Near Perfect types of somatic embryos were categorized as competent, while Limited/No Meristematic activity, Disrupted Internal Anatomy, and Proliferating types were categorized as noncompetent with respect to their conversion ability. Lack of organized shoot development in somatic embryos of sweetpotato was attributed to the following abnormalities: 1) lack of an organized apical meristem, 2) sparsity of dividing cells in the apical region, 3) flattened apical meristem, 4) multiple meristemoids and/or diffuse meristematic activity throughout the embryo. A morphological fate map of most of the torpedo and cotyledonary embryo variants was identified, which will be beneficial in synthetic seeding and transgenic research and development of sweetpotato.
Somatic Embryogenesis Using Cucumis sativus (L.) Cotyledons
Authors: Guedes N.M.P. , Jennings P.H.
Published: February 2019

To improve somatic embryogenesis of Cucumis sativus, two types of explants (cotyledons and stem sections) were cultured on Murashige and Skoog (MS) media supplemented with 2,4-D (2.0 mg·L–1) + kinetin (0.5 mg·L–1). After 4 weeks, the embryogenic callus was transferred for 2 weeks to MS + NAA (1.0 mg·L–1) for embryo development. Stem sections failed to develop embryos while cotyledons responded with 14% embryo formation. The embryos were transferred to MS without hormones for 4 weeks to allow for plantlet growth. These embryos developed only shoots. To improve on the successful generation of embryos with root and shoot development, the procedures used above were repeated, but the cotyledons were cut into three sections to be used as explants. Each transverse section of the cotyledon was approximately 2–3 mm wide. All sections produced callus but not all of them were embryogenic. From the first section (cotyledon base), the second (between the first and third section) and the third section (furthest from the cotyledon base), respectively, 58%, 31%, and 5% embryo development occurred. Those embryos from the basal cotyledon sections regenerated 10 plantlets, 5 with shoots and roots and 5 with only shoots. Approaches to enhance somatic embryogenesis, and shoot and root development, will be discussed.
Propagation of Selected Culinary and Ornamental Herbs
Authors: Schroeder J.R. , Le Duc Alice
Published: February 2019

Ten culinary and ornamental herbs were evaluated for time and quality of rooting of tip cuttings. The taxa included in the study were oregano (Origanum vulgare), lemon thyme (Thymus ×citriodorata), applemint (Mentha suavolens), Persian catnip (Nepeta ×faassenii), lemon balm (Melissa officinalis), southernwood (Artemisia abrotanum), caraway thyme (Thymus herba-barona), hyssop (Hyssopus officinalis), `Blue Wonder' catnip (Nepeta `Blue Wonder'), pineapplemint (Mentha suavolens var. variegata). Four replicates of each species were used. The cuttings, untreated and rooting hormone treated, were placed under intermittent mist, then cuttings potted when a 1- to 1.5-inch root ball had developed. Most of the stock suffered from some chlorosis during rooting; southernwood cuttings particularly displayed severe chlorosis which was overcome with 2 weeks of constant-feed fertilizer after potting. Oregano displayed the best results, rooting in seven days with or without treatment. It produced a sellable 4-inch pot in 31 days from sticking the cuttings. Lemon thyme, applemint, Persian catnip, and lemon balm all rooted in 14 days if treated. No difference was observed in days to rooting between treated and untreated lemon thyme. Untreated cuttings of lemon balm, applemint, and Persian catnip rooted in 25 to 30 days. Treated applemint cuttings not only rooted more quickly but produced a marketable 4-inch pot in significantly less time. Southernwood and caraway thyme rooted in 25 days, with no significant difference between treated and untreated cuttings. Hyssop, pineapplemint, and `Blue Wonder' catnip took about 30 days, also with no significant difference between treated and untreated cuttings.
Influence of Substrate, Auxin, and Propagation Period on Rooting of Eight Florist Azalea Cultivars
Authors: Lambert Marie-Josee , Dansereau Blanche , Gauthier Fabienne
Published: February 2019

During Spring–Summer 1995, cuttings of eight Rhododendron simsii cultivars `Dorothy Gish', `Jacinth', `Paloma', `White Gish', `Friedhelm Scherrer', `Gloria', `Helmut Vogel', and `Inga' were rooted using two substrates combined with or without (control) four rooting hormone treatments. The rooting substrate was composed of either pure peat moss or 80% peatmoss and 20% perlite. The basal end of cuttings were dipped into one of the four hormone treatments: IBA (Stim-Root powder) at 4000 and 8000 ppm, or IBA (liquid Stim-Root) at 5000 and 10,000 ppm. This experiment was repeated in Fall 1995 and in Winter 1996 to determine the effect of seasonal period on rooting. Spring is the optimal period for rooting the cultivars used in this study. Highest percentage of rooting was obtained with cultivars `Helmut Vogel', `Inga', `Jacinth', and `Paloma'. Dry mass of cultivars propagated using liquid formulation was significantly increased during this period. Substrates did not significantly effect rooting percentage and quality and dry root mass.
Effect of IBA Concentration on Rooting of Sugar Maple
Authors: Khatamian Houchang , Pair John C.
Published: February 2019

Softwood cuttings of `Commemoration' and two selections of Caddo maple (83-NR3 and 90-7185) were collected on 24 May 1995 from specimen trees located at the Wichita Horticultural Research Center. Uniform cuttings 14–19 cm long containing 4–5 leaves were dipped in selected IBA hormone solutions for 10 seconds and stuck in a rooting mix consisting of 30% Canadian sphagnum peat and 70% perlite (v/v). The experiment was conducted in a greenhouse located at Kansas State Univ. To achieve a high relative humidity around the cuttings, a fog generator (Humidifan, turbo XE 1000) was installed and operated for 12 hours per day. The experiment was a factorial design with 3 maple selections, 4 hormone concentrations and 3 replications. After 10 weeks cuttings were evaluated for rooting using a visual rating scale of 1–5. There was a significant difference between the maple cultivars and the IBA levels tested. `Commemoration' cuttings rooted the best among the maple cultivars with all of the IBA treatments. The best rooting of Caddo maple selection (83-NR3) took place with 10,000 ppm IBA. None of the cuttings of the other Caddo maple selection (90-7185) rooted regardless of the hormone concentration. The rooted cuttings were potted in 15 cm plastic containers filled with Metro Mix 702 for future production.
Postharvest Stability of Guayule Natural Rubber and Resin during Long-term Cold Storage
Authors: Grote-Flores C.D. , Latigo G.V. , Bradford J.O. , Kuti J.O.
Published: February 2019

Guayule shrub (Parthenium argentatum Gray) is a source of natural rubber resin and latex. Because guayule does not produce natural antioxidants, considerable amounts of rubber and resin are lost after harvest. The effect of long (2–7 years) cold storage on postharvest stability of rubber and resin contents in selected dryland guayule breeding lines were compared. While most genotypes tested showed significant decline in rubber and/or resin content during the storage, few genotypes consistently maintained or increased the amounts of rubber or resin content during storage. The mechanisms of postharvest degradation or synthesis of rubber and resin in harvested guayule plant materials need to be studied further.
Response of Mango Fruit to Potassium Permanganate as an Ethylene Absorbent during Storage
Authors: Zambrano Judith , Briceño Sagrario , Mendez Clara , Castellano Eliseo
Published: February 2019

Mango fruit of `Palmer' and `Keitt' were harvested at the preclimacteric stage. An inexpensive ethylene absorbent was made by mixing aqueous KMnO4 with vermiculite and silicagel as support material. Fruits were treated with the mixture of vermiculite–KMnO4 and silicagel–KMnO4 as ethylene absorbents and stored at 10 and 15°C for 18 days. Fruits were evaluated for skin and pulp color, total soluble solids, titratable acidity and weight loss at interval of 3 days. Ethylene absorbents had no significant effect on skin color parameters (lightness, hue, and chroma). However differences due to ethylene absorbents and temperature storage were evident on pulp color parameters. Soluble solids content and titratable acidity were affected by ethylene absorbent and temperature storage. The percent of weight loss increased with temperature and with duration of storage.
Sorting Fruit by Quality: What Chloroplast Fluorescence Can Tell Us
Authors: Song J. , Armstrong P.R , Beaudry R.M.
Published: February 2019

Chloroplast fluorescence as a nondestructive tool for assessing `Red Delicious', `Golden Delicious' and `Law Rome' apple fruit quality was examined after approximately 4.5 months storage. Fluorometry parameters of minimal fluorescence (Fo), maximal fluorescence (Fm) and quantum yield (Fm-Fo)/Fm (otherwise denoted as Fv/Fm) were determined. All fluorescence parameters declined with time as apple fruit were maintained at 22°C in air. Fv/Fm was found to correlate well with firmness for `Red Delicious' fruit. A decline in Fo with time correlated very well with the development of yellow coloration of `Golden Delicious' fruit. The Fv/Fm value was consistently higher for controlled-atmosphere (CA) stored fruit than for regular-air (RA) stored fruit. When CA and RA stored `Law Rome' fruit were combined and a Fv/Fm value of 0.685 was used to resegregate fruit from the two storage regimes. Resegregation was achieved with 75% accuracy, with only 5% RA-stored fruit incorrectly identified as CA-stored. The accuracy, speed of assessment and light-based nature of fluorometry suggest it may have some practical use as a tool for sorting apple and other chlorophyll-containing fruit on commercial packinglines.
Carbon Dioxide Injury of `Empire' Apples
Authors: Watkins Christopher B. , Silsby Kenneth J.
Published: February 2019

Occasional occurrence of a superficial skin injury associated with CA storage can cause severe commercial loss in the `Empire' cultivar in the northeast. To develop industry strategies to prevent losses due to the disorder, we have examined a number of factors related to its occurrence. 1) Fruit from six orchards were stored with 2% or 5% CO2 (with 2% O2) at 0.5 or 3°C for 6 or 9 months. Orchard variation in susceptibility was high. Preharvest factors such as maturity or mineral levels in the fruit did not account for these differences. Incidence of the disorder was much higher at 5% than at 2% CO2. However, temperature did not affect the extent of injury. 2) Exposure of fruit stored at 2% CO2/2% O2 to 5% CO2 at 4-week intervals from harvest until 20 weeks indicated that fruit were most susceptible to injury between 0 and 8 weeks. 3) A postharvest treatment with diphenylamine (DPA) prevented occurrence of the disorder, ethanol reduced it, but ascorbic acid had little effect. 4) Fruit were held at storage temperatures for up to 10 days before exposure to either 2% or 5% CO2. Injury was highest in fruit exposed one day after harvest and negligible when exposed after 10 days. Collectively the results indicate that rapid CA can aggravate the disorder if care is not taken to maintain low CO2 concentrations in the storage atmosphere but that use of DPA for control of superficial scald will prevent its occurrence.
Farnesene and Trienes in Apple Peel Quantified by HPLC
Authors: Whitaker Bruce D. , Solomos Theophanes
Published: February 2019

Farnesene and its conjugated triene oxidation products in apple peel are positively correlated with, and thought to be involved in, the storage disorder superficial scald. Levels of these compounds are often estimated by dipping fruit in hexane and measuring the absorbance of the crude extracts at 232 nm (farnesene) and 269 or 281 minus 290 nm (trienes). We have devised a C18 HPLC method with UV detection at 232 and 269 nm that allows the simultaneous quantitation of 80 ng of farnesene and trienes. Using this method we have confirmed the recent report that one conjugated trien-6-ol comprises 90% of the stable oxidation products of farnesene. It was also found that crude hexane extracts of apple peel can give spuriously high values for farnesene and/or trienes when levels of these compounds are low and other UV-absorbing components are present. A group of compounds unrelated to farnesene, with an absorbance maximum at ≈259 nm, were noted in the peel of cv. Gala apples, which produced little farnesene or trienol. This may explain the report that fruit with a high ratio of A258nm/A281nm in peel extracts have a low incidence of scald. The new HPLC method will be applied in subsequent studies of postharvest factors involved in regulation of farnesene synthesis and oxidation.
Nondestructive Quality Screening of Green Tomatoes Using Ethylene Gas
Authors: Maul F. , Sargent S.A.
Published: February 2019

The effects of prolonged ethylene exposure on external and internal quality parameters of tomato fruits were studied in order to explore the feasibility of its use as a nondestructive technique for screening immature and inferior quality fruit. `Agriset' and `CPT-5' tomatoes were hand harvested at Stage 1 (green) and held at 20°C and 50 ppm ethylene for 1-7 days. Each 24 hours, fruits reaching Stage 2 (breaker) were removed from C2H4 and transferred to 20°C air for subsequent ripening. Tomatoes were considered at edible maturity upon reaching full red-ripe stage and 4 mm deformation and final quality parameters were determined. For both cultivars, fruits which required prolonged C2H4 exposure to reach Stage 2 had lower overall visual appearance. `Agriset' tomatoes which required short exposure times to C2H4 (1 to 3 days) had somewhat higher quality than those requiring prolonged times (4 or 5 days). Days to reach edible maturity were 9.5 and 7.7, respectively. For the short exposure times, peel color was more intense (higher chroma value), while soluble solids content and total sugars were significantly higher (P = 0.05). Quality of `CPT-5' tomatoes was not adversely affected until requiring 6 or 7 days exposure to C2H4. Days to reach edible maturity decreased from an average of 12.5 to 11.0 for 1 to 5 or for 6 to 7 days exposure, respectively. For fruits requiring 7 days exposure, soluble solids content, total sugars and pH were significantly higher than for those reaching Stage 2 in fewer days. There were no significant differences in titratable acidity or ascorbic acid content for either cultivar.
Intermittent Warming Reduces Tomato Fruit Quality Deterioration during Cold Storage
Authors: Hakim Abdul , Kaukovirta Errki , Pehu Eija , Voipio Irma
Published: February 2019

Mature green tomatoes (cv. Vibelco) were stored at 2°C for 2, 3, and 4 weeks. Intermittent warming treatments for 12, 24, and 36 hours at 24°C were applied at the end of every week. Control Fruit were held continuously at 2°C. All fruit were subjected to poststorage ripening at 24°C for 7 days. Fruit decay, chlorophyll and lycopene content, fruit firmness, pH, TSS and TA were detected after storage or 7 days after transfer to 24°C. Results were compared between control and intermittently warmed fruit when stored at 2°C for 2, 3, and 4 weeks. Compared to fruit kept continuously at 2°C, intermittent warming at 24°C for 12, 24, and 36 hours reduced decay, increased chlorophyll disappearance, lycopene synthesis, and fruit firmness, enhanced pH and TSS, and declined TA. Fruit intermittently warmed for 36 hours/week showed the least decay, higher chlorophyll disappearance, and lycopene synthesis; retention of fruit firmness, pH, and TSS; and lower TA than fruit intermittently warmed for 12 and 24 hours/week. Decay percentage, lycopene content, pH, and TSS were increased from 2 to 4 weeks, but chlorophyll content, fruit firmness, and TA were declined.
Carbohydrate Contents of Xylem and Cortex Tissues of Carrot Roots
Authors: Qin Mingbo , Ke Shanqiang , Lafta Abbas , Duysen Murray E. , Lee Chiwon W.
Published: February 2019

The relative concentrations of sucrose, glucose, and starch in the xylem and cortex tissues of carrot (Daucus carota) roots were evaluated after harvest and during storage. For the three cultivars (Apache, Bolero, Danvers 126) tested, the cortex tissue contained 76.6, 49.1, and 33.6 mg·g–1 dry weight of sucrose, glucose, and starch, respectively. In comparison, the average contents of sucrose, glucose, and starch in xylem tissues were 57.4, 52.4, and 11.6 mg·g–1 dry weight, respectively. In general, cortex tissue contained higher concentrations of sucrose and starch than the xylem tissues. The glucose concentrations in cortex and xylem were similar. In `Apache', for example, the cortex tissue contained 40% and 57% higher concentrations of sucrose and starch, respectively, than the xylem tissues, whereas glucose content of the cortex was only 7.5% higher than that of the xylem. Since sweetness is largely influenced by sucrose, the relative volume of cortex to xylem must be considered in evaluating carrot cultivars for sweet taste.
Effect of Prestorage Thermal Treatments, Vacuum Infused Mycostatic Treatments, and Storage Relative Humidity on the Stability of Chinese Chestnuts
Authors: Smith Durward , Norton Joseph D.
Published: February 2019

Chinese chestnuts (Castanea molissima Blume) are a highly perishable commodity which requires artificial storage means and is easily spoiled by fungi. This investigation was designed to develop processes and adapt equipment for more efficient processing and storage of Chinese chestnuts, establish parameters for optimum fresh storage, and to compare the yields and qualities of the chestnuts processed by the test methods. Chinese chestnuts were prepared for fresh storage by vacuum infusing mycostatic solutions and modified starch coatings inside the shells. Vacuum treatment facilitated perfect contact of these solutions with the surfaces of the kernels, and was a more rapid method than atmospheric or pressure soaking methods. Vacuum infused pretreatments limited desiccation, minimized spoilage, reduced storage weight losses, and yielded products with better color and texture than conventional storage. Thermal treatments for surface pasteurization were defined. A storage relative humidity of 87% was found to be optimal.
Cooperative Cryopreservation of Dormant Apple Buds from the Canadian Clonal Gene Bank
Authors: Forsline Philip L. , Luffman Margie , Warner John , Towill Leigh E.
Published: February 2019

Based on protocols developed by the Plant Genetic Resources Unit (PGRU), Geneva, NY and the National Seed Storage Laboratory, Fort Collins, Colo., nearly 40% of the 2500-accession USDA–ARS Malus germplasm collection has been preserved cryogenically. Recent program changes require the entire Canadian Malus collection of 700 accessions at the Canadian Clonal Genebank, Trenton, Ont., be moved to a new location in Harrow, Ont., by the end of 1996. This provided an opportunity to utilize cryogenic storage during repropagation and reestablishment to develop a security backup for the collection. In a cooperative experiment, dormant buds of four Canadian Malus accessions were collected in Trenton and cryopreserved in Geneva in February 1995. Field-level moisture of dormant buds ranged from 45% to 50%. Three levels of bud desiccation were tested: 25%, 30% (current standard), and 35%. The desiccated buds were containerized and slowly frozen to –30°C, plunged into liquid nitrogen, and held for one month at Geneva prior to recovery testing by bud-grafting at Geneva and Trenton. Results were identical at both sites. We obtained 60% recovery at 30% and 35% moisture levels and 80% recovery at 25% moisture across all four accessions. Further studies on a broader range of germplasm will determine if desiccation to the 25% level is superior to the 30% level. Meanwhile, we have initiated a cooperative project to cryopreserve 350 accessions unique to the Canadian collection at Ft. Collins.
Effects of Antitranspirant and Leaching on Medium Solution Osmotic Potential, Leaf Gas Exchange, Abscisic Acid Content, and Growth of `Early Girl' Tomato Plants
Authors: Gu Sanliang , Cheng Lailiang , Fuchigami Leslie H.
Published: February 2019

`Early Girl' tomato plants (Lycopersicon esculentum Mill.) were grown in a medium containing peatmoss and perlite (60%:40% by volume). The medium was drenched with 0% or 5% GLK-8924 antitranspirant. Half of the plants were flushed daily with 250 mL water (leaching), and the other half were subirrigated by capillarity. The solution osmotic potential of the medium was reduced significantly by 5% GLK 8924 treatment, then recovered gradually to the control level after 3 days with leaching or 10 days without leaching. Leaf stomatal conductance, transpiration rate, and plant growth were depressed by the antitranspirant application, and the depression was alleviated by leaching. Neither antitranspirant GLK-8924 treatment nor leaching influenced leaf abscisic acid (ABA) content. The effect of the antitranspirant on leaf gas exchange and plant growth was highly related to the reduction in the solution osmotic potential of the medium, but not to leaf ABA content. Younger leaves had higher stomatal conductance and transpiration rate but lower ABA content than older leaves in general.
Leaf Conductance and Xylem Water Potential of Ecotypes and Cultivars of Acer saccharum and A. nigrum
Authors: Yuza Steve C. , Youngman Art L. , Pair John C.
Published: February 2019

This study examined physical factors and physiological responses of five different ecotypes and cultivars of Acer saccharum and A. nigrum. The objective was to determine variations in leaf conductance and xylem water potential and correlations associated with their natural geographic distribution. Compared were two ecotypes of sugar maple, Caddo and Wichita Mountains, native to Oklahoma with cultivars Green Mountain and Legacy, plus black maple seedlings from Iowa. Measurements taken included leaf conductance, xylem water potential and soil water potential in a replicated block of 15-year-old trees. The two ecotypes had consistently higher photosynthetic rates, stomatal conductance and transpiration rates than other selections. Xylem water potentials were significantly higher for Caddo maples than Green Mountain, Legacy and Acer nigrum in both predawn and midday samples. This difference in water availability can be associated with a tendency for Caddo to vary its stomatal conductance. The other tree types maintained stable stomatal conductances.
Honor's Students as Peer Tutors for Problem-based Learning
Authors: Kitto S. , Griffiths L.
Published: February 2019

The course “Biotechnology: Science and Socioeconomic Issues” has used problem-based learning (PBL) during the last quarter of the course for the past 3 years. One of the challenges of using PBL in medium-sized and larger classes is finding a way to facilitate each group of students with a limited number of qualified facilitators while avoiding unmanageably large numbers of students per group. This past year (95F) the course had both a nonhonor's and an honor's section. The honor's section met an additional hour each week to learn about PBL and peer tutoring skills. Training students to be peer tutors was divided up into four parts: 1) the science behind PBL, 2) experience working through a previously developed case study, 3) development of a case study, and 4) peer tutoring case studies in the non-honor's section. We will discuss the process of training students to be effective peer tutors for PBL.
Interdisciplinary Horticulture Course Benefits Local Youth
Authors: Olien Mary E. , Brittain Jere A. , Mey Brenda J Vander
Published: February 2019

“Garden Experiences in Youth Development” is a two-credit, (one lecture, one lab) 400-level course offered each spring semester by the Dept. of Horticulture at Clemson Univ. For the past 3 years, the course has met the following specific needs: 1) requests by horticulture students for more experiences related to horticulture and human well-being; 2) opportunities for other majors whose careers will or may focus on children to learn and to use horticulture with children; 3) a source of adult leaders for an after school children's gardening program at the South Carolina Botanical Garden. The lecture portion addresses issues related to children in horticulture, planning nature and gardening related activities with children, as well as a general background in gardening for nonmajors. During the lab, the students gain hands-on experience working with children who participate in Sprouting Wings, an after school gardening program offered by the South Carolina Botanical Garden. A multi-source evaluation of the effectiveness of the course and the youth program is being conducted. The poster will present the course syllabus, copies of selected course readings, outlines of student generated projects, and the results of the program evaluation.
Comparison of the Physical Characteristics of Growing Media Containing Composted Oak Sawdust and Sphagnum Peat
Authors: Jeneidi F. M. , Starbuck C. J.
Published: February 2019

The physical characteristics of a container growing medium containing 2 oak sawdust composted with poultry manure: 1 vermiculite: 1 perlite were compared with those of a similar medium containing sphagnum peat rather than compost. Both media were amended with inorganic nutrients based on laboratory analysis to make them nutritionally comparable and with AquaGro wetting agent at 800 g·m–3. Moisture release characteristics of the media were evaluated using tension cups in which desorption at 5, 10, 20, 40, 80, 100, and 160 cm of water was measured. While bulk density of the peat mix (0.129 g·cm–3) was, significantly lower than that of the compost mix (0.157 g·cm–3), total porosity of the peat mix (84%) was significantly greater than that of the compost mix (79%). Air-filled and water-filled porosities of the peat and compost mixes were 18.2% 16.2% and 75.2% 70.5% of container volume, respectively. While the peat mix held more water at tensions between 5 and 20 cm, there was no significant difference between the volumetric water contents of the two media between 20 and 160 cm. Fresh and dry weights of corn plants grown for 3 weeks in compost- and peat-based media were not significantly different.
Shredded Waste Tires as a Growing Media Amendment for Production of Flowering Vinca
Authors: Panter Karen L. , Newman Steven E. , Roll Michael J.
Published: February 2019

Catharanthus roseus plants were grown in three media, each containing one of two by-products of shredded waste tires. The media were no. 1) 1 rubber*: 1 peat moss, no. 2) 1 rubber*: 1 vermiculite: 2 peat moss, and no. 3) 2 rubber*: 1 vermiculite: 1 peat moss (by volume) where rubber* indicates either 0.6 cm shredded rubber or a fibrous by-product. Control plants were grown in 1 peatmoss: 1 rockwool and 1 vermiculite: 1 peatmoss (by volume). Catharanthus roseus cv. Peppermint Cooler plants were grown for 7 weeks in 10-cm containers at a commercial Denver-area greenhouse. Data taken included plant heights, plant widths, flowers per stem, and dry weights. Visually, plants grown in the no. 2 mix, with either fiber or 0.6-cm rubber, were similar to the controls and superior to the other two mixes. Ending plant heights were similar among the two controls and no. 2 with fiber and were taller than all other combinations. Flower numbers were greater in the 1 rockwool: 1 peat moss control and no. 2 mix with fiber than any other treatment. The same was true for stem number and dry weight. Results indicate that the no. 2 mix of 1 fiber: 1 vermiculite: 2 peatmoss has potential for container crop production.
Growth Index and Disease Ratings of 60 Lilac Cultivars in Tennessee
Authors: Witte W.T. , Windham M.T. , Sauve R.J. , Flanagan P.C.
Published: February 2019

Sixty accessions of commercially available lilac cultivars were planted May 1994 and immediately placed under drip irrigation and fertilized regularly. Powdery mildew appeared in July 1994 and was rated on a scale of 0 (healthy) to 5 (totally mildewed) in July, August, and September. Mean growth index (GI = cm height + cm mean width) was calculated for each cultivar in Fall 1994 and 1995. Fastest growth (GI = 75 to 45 respectively) occurred in the group including chinensis `Rothomagensis', meyeri `Dwarf Korean', reticulata `Ivory Silk', prestoniae `Isabella', `Mrs. Harvey Bickle', `Excel', `Katherine Havemeyer', `Mme. F. Morel', `Silver King', `Leon Gambetta', `Mount Baker', and microphylla `Superba'. Data will be presented on powdery mildew ratings for the 1995 season.
Evaluation of Harmony and 1616 Grape Grafted Rootstocks Using the Cultivar Fantasy Seedless as Scion and Control
Authors: de Jesus Valenzuela-Ruiz Manuel , Grijalva-Contreras Raul Leonel , Lopez-Carvajal Arturo , Juarez-Gonzalez Rogelio
Published: February 2019

Caborca is the most important viticultural area in Mexico; however, in the last 10 years, the nematode population become a big problem and many vineyards are affected for nematode attack. Our objective was to evaluate the susceptibility or resistance of two grape grafted rootstocks and direct planted `Fantasy Seedless' cultivar as scion and control. The observed results at second production year were 1800, 950. and 550 table grape boxes/ha for Harmony, 1616 grafted rootstocks and direct-planted Fantasy S, respectively; also, table grape from Harmony rootstock showed better sizes and quality than others. The nematode populations were 0.7, 2.0, and 75 nodes/50 g of roots for Harmony, 1616 and direct-planted Fantasy, respectively. No one treatments were affected in the phenology stages during the seasons.