bluuebunny/crossref_metadata_2025 huggingface dataset:
Sink-source Transition in Peach Leaves during Shoot Development
Authors: Marchi Susanna , Sebastiani Luca , Gucci Riccardo , Tognetti Roberto
Published: January 2019

Net photosynthesis, dark respiration, chlorophyll and carbohydrate content, and leaf and shoot growth of deciduous peach [Prunus persica (L.) Batsch] saplings, grown in greenhouse conditions, were measured to assess changes in carbon balance during leaf development. The 6th, 12th, and 16th leaf node were measured from the first flush at the base through expansion to maturity (the first node being the oldest). Shoot and leaves expanded following a sigmoid pattern in all nodes. The shape of the logistic curve did not vary between the 6th and the 16th leaf node, while the 12th leaf node showed a steeper response, suggesting that the latter reached 50% expansion relatively earlier. Photosynthesis varied with leaf development as young leaves had low CO2 assimilation rates that were reflected in their chlorophyll concentration. Net daily CO2 assimilation was negative in young expanding leaves. The sink-source transition, defined to be the time when the increase in daily carbohydrate exchange rate exceeded the daily increase in leaf carbohydrate content, occurred before full leaf expansion. The transition from import to export was attained 11-12 days after budbreak (corresponding to 41% to 45% of full leaf expansion) for the 6th leaf, about 7-9 days after (38% to 52% of full expansion) for the 12th leaf and after 9-10 days (32% to 38% of full expansion) for the 16th leaf. Below 30% to 50% of full expansion leaves might not respond to assimilate requirements from sinks, being sinks themselves.
Irrigation Timing Relative to Head Development Influences Yield Components, Sugar Levels, and Glucosinolate Concentrations in Cabbage
Authors: Radovich Theodore J.K. , Kleinhenz Matthew D. , Streeter John G.
Published: January 2019

To better understand the influence of environmental factors on components of crop productivity and nutritional and sensory quality parameters, the fresh-market cabbage (Brassica oleracea L. Capitata Group) `Bravo' was irrigated at different periods relative to head development in 2002 and 2003 at the Ohio Agricultural Research and Development Center in Wooster. Irrigation was provided to plots either: 1) from planting to maturity, 2) during frame development only, or 3) during head development only. Control plants received no irrigation after plant establishment. Irrigation timing relative to crop stage significantly affected all head characteristics with the greatest differences between cabbage receiving irrigation during head development and cabbage not irrigated during head development. On average, heads from cabbage irrigated during head development were heavier, larger, less pointed, and had less volume occupied by the core than heads from cabbage not irrigated during head development. A positive, linear relationship (r2 = 0.89) was found between head volume and head weight. Across years, combined head fructose and glucose concentrations were significantly greater and sucrose concentrations significantly lower in cabbage receiving irrigation during head development than in cabbage not irrigated during head development. Total and individual glucosinolate levels were greater in cabbage not irrigated during head development relative to cabbage receiving irrigation during head development. Head weight, fructose and glucose were positively related to the proportion of estimated crop evapotranspiration replaced by irrigation during head development, while the opposite response was observed in head sucrose and total and indole glucosinolate concentrations.
Antioxidant Potential and Peroxidative State of `Golden Smoothee' Apples Treated with 1-Methylcyclopropene
Authors: Vilaplana Rosa , Valentines M. Carme , Toivonen Peter , Larrigaudière Christian
Published: January 2019

In order to determine the effects that 1-methylcyclopropene (1-MCP) may have on antioxidant metabolism during cold storage, apples (Malus ×domestica Borkh. cv. Golden Smoothee) were treated with 625 nL·L−1 1-MCP immediately after harvest and stored in air for 3 months. Differences in total antioxidant activity and ascorbate levels were determined during storage and related to the activity of the antioxidant enzymes superoxide dismutase [SOD (EC 1.15.1.1)], catalase [CAT (EC 1.11.1.6)], and peroxidase [POX (EC 1.11.1.7)] in pulp. The level of oxidative stress in the pulp tissue was also established by determining changes in levels of hydrogen peroxide and in the content of peroxidative markers during storage. Controls and 1-MCP-treated fruit exhibited similar changes in total antioxidant activity and ascorbate levels. However, significant differences in oxidative stress levels were found between treated and untreated fruit. 1-MCP-treated fruit exhibited lower levels of hydrogen peroxide and significantly lower levels in peroxidative markers, especially at the end of the storage period. In line with this last result, 1-MCP-treated fruit also exhibited greater enzymatic antioxidant potential and, more specifically, a higher level of POX activity. Collectively, these results showed that 1-MCP did not detrimentally affect the antioxidant potential of the fruit and provided evidence to support the hypothesis that the beneficial effects of 1-MCP on ripening are not exclusively limited to its effect on ethylene, but also include direct effects on peroxidation and POX enzyme activity.
Uptake and Assimilation of Nitrate and Iron in Two Vaccinium Species as Affected by External Nitrate Concentration
Authors: Darnell Rebecca L. , Hiss Steven A.
Published: January 2019

Most Vaccinium species have narrow soil adaptation and are limited to soils that have low pH, high available iron (Fe), and nitrogen (N) primarily in the ammonium (NH4+) form. Vaccinium arboreum Marsh. is a wild species that can tolerate a wider range of soil conditions, including higher pH and nitrate (NO3-) as the predominant N form. This wider soil adaptation may be related to the ability of V. arboreum to acquire Fe and NO3- more efficiently than cultivated Vaccinium species, such as V. corymbosum L. interspecific hybrid (southern highbush). Nitrate and Fe uptake, and nitrate reductase (NR) and ferric chelate reductase (FCR) activities were compared in these two species grown hydroponically in either 1.0 or 5.0 mm NO3-. Nitrate uptake rate (on a whole-plant and FW basis) and root NR activity were significantly greater in V. arboreum compared with V. corymbosum. Iron uptake on a FW basis was also greater in V. arboreum, and was correlated with higher root FCR activity than was found in V. corymbosum. Increased Fe and NO3- uptake/assimilation in V. arboreum were reflected in increased organ and whole-plant dry weights compared with V. corymbosum. Vaccinium arboreum appears to be more efficient in acquiring and assimilating NO3- and Fe than is the cultivated species, V. corymbosum. This may partially explain the wider soil adaptation of V. arboreum.
Statistical Analysis of Mixed Model Factorial Experiments with Missing Factor Combinations: The Case of Asynchronous Cyclic Drought Data
Authors: VanLeeuwen Dawn M. , Hilaire Rolston St. , Bsoul Emad Y.
Published: January 2019

Statistical analysis of data from repeated measures experiments with missing factor combinations encounters multiple complications. Data from asynchronous cyclic drought experiments incorporate unequal numbers of drought cycles for different sources and provide an example of data both with repeated measures and missing factor combinations. Repeated measures data are problematic because typical analyses with PROC GLM do not allow the researcher to compare candidate covariance structures. In contrast, PROC MIXED allows comparison of covariance structures and several options for modeling serial correlation and variance heterogeneity. When there are missing factor combinations, the cross-classified model traditionally used for synchronized trials is inappropriate. For asynchronous data, some least squares means estimates for treatment and source main effects, and treatment by source interaction effects are inestimable. The objectives of this paper were to use an asynchronous drought cycle data set to 1) model an appropriate covariance structure using mixed models, and 2) compare the cross-classified fixed effects model to drought cycle nested within source models. We used a data set of midday water potential measurements taken during a cyclic drought study of 15 half-siblings of bigtooth maples (Acer grandidentatum Nutt.) indigenous to Arizona, New Mexico, Texas, and Utah. Data were analyzed using SAS PROC MIXED software. Information criteria lead to the selection of a model incorporating separate compound symmetric covariance structures for the two irrigation treatment groups. When using nested models in the fixed portion of the model, there are no missing factors because drought cycle is not treated as a crossed experimental factor. Nested models provided meaningful F tests and estimated all the least squares means, but the cross-classified model did not. Furthermore, the nested models adequately compared the treatment effect of sources subjected to asynchronous drought events. We conclude that researchers wishing to analyze data from asynchronous drought trials must consider using mixed models with nested fixed effects.
DNA Sequence Analysis of Microsatellite Markers Enhances Their Efficiency for Germplasm Management in an Italian Olive Collection
Authors: Muzzalupo Innocenzo , Lombardo Nicola , Musacchio Aldo , Noce Maria Elena , Pellegrino Giuseppe , Perri Enzo , Sajjad Ashif
Published: January 2019

Genetic diversity studies using microsatelite analysis were carried out in a set of 39 accessions of Olea europaea L., corresponding to the majority of the regional autochthon germplasm in Apulia. Samples of olive leaves were harvested from plants growing in the olive germplasm collection of the Consiglio per la Ricerca e Sperimentazione in Agricoltura (C.R.A.) - Istituto Sperimentale per l'Olivicoltura at Rende in Cosenza Italy. Herein, we evaluated the extent to which microsatellite analysis using electrophoresis was capable of identifying traditional olive cultivars. In addition, the DNA sequence of all amplicons was determined and the number of repeat units was established for each sample. Using five loci, electrophoretic analysis identified 24 genotype profiles, while DNA sequence analysis detected 28 different genotype profiles, identifying 54% of cultivars. The remaining 46% were composed of seven different accession groups containing genetically indistinguishable cultivars, which are presumably synonyms. This study demonstrates the utility of microsatellite markers for management of olive germplasm and points out the high level of polymorphisms in microsatellite repeats when coupled with DNA sequence analysis. The establishment of genetic relationships among cultivars in the Apulian germplasm collection allows for the construction of a molecular database that can be used to establish the genetic relationships between known and unknown cultivars.
Comparison Among Sweet Corn Heterotic Patterns
Authors: Revilla P. , Rodríguez V.M. , Malvar R.A. , Butrón A. , Ordás A.
Published: January 2019

Four sweet corn (Zea mays L.) heterotic patterns have been reported among sugary1 (su1) open-pollinated cultivars: two among sweet corn cultivars (`Golden Bantam' × `Country Gentleman' and `Golden Bantam' × `Stowell's Evergreen'), one related to the `Reid' × `Lancaster' field corn heterotic pattern (`NE-HY-13A' × `NE-HY-13B'), and one related to the northern × southern Spain field corn heterotic pattern (`EPS31' × `EPS32'). The objective of this research was to compare the performance of sweet corn heterotic patterns. The four crosses and their seven parents were evaluated in 2 years, at two environments in northwestern Spain, as well as in a cold chamber. `Golden Bantam' × `Stowell's Evergreen' and `Golden Bantam' × `Country Gentleman' had poorer agronomic performance and better ear quality than `NE-HY-13A' × `NE-HY-13B' and `EPS31' × `EPS32'. `Golden Bantam' × `Stowell's Evergreen' had the best cold tolerance in the cold chamber. Earliness, emergence, and early vigor were higher for `EPS31' × `EPS32', related to the northern × southern Spain field corn heterotic pattern. Heterosis was positive and significant for several traits for `Golden Bantam' × `Stowell's Evergreen' and `Golden Bantam' × `Country Gentleman,' while heterosis was not significant for `NE-HY-13A' × `NE-HY-13B' and `EPS31' × `EPS32'. The objective of capitalizing on the `Reid' × `Lancaster' and the northern × southern Spain field corn heterotic patterns for improving sweet corn has failed. We believe that heterosis is lost when field corn heterotic patterns are combined with sweet corn, due to incompatibility in gene combination among sweet and field corn genetic backgrounds.
Changes in the Morphology and Cation Content of a Bambusa edulis Xylem Mutant, vse, Derived from Somaclonal Variation
Authors: Lin Choun-Sea , Lin Huey-Ling , Jane Wann-Neng , Hsiao Han-Wen , Lin Chung-Chih , Jheng Fang-Yi , Chang Wei-Chin
Published: January 2019

A xylem mutant (vse) was isolated from a Bambusa edulis (Odashima) Keng plantlet following vegetative micropropagation and subculture for 7 consecutive years and induced to proliferate in medium supplemented with 0.1 mg·L-1 (0.5 μm) thidiazuron (TDZ) and to develop roots in medium supplemented with 5 mg·L-1 (26.9 μm) α-naphthaleneacetic acid (NAA). Subsequent investigations comparing the growth habits of mutant plantlets with those of the wild type indicated that the growth of the former was retarded in a greenhouse. Several morphological abnormalities were observed in the vse mutant: it had thinner stems with fewer trichromes on the surface; the xylem vessels were smaller in diameter and contained crystal-like structures in the pith; the leaves were shorter and narrower with a sharp leaf blade angle; the roots were thinner and contained fewer xylem cells. The cation concentrations of both the mutant and wild type were similar in the in vitro analysis, except for those of iron and potassium, which were lower in mutant leaves in vivo. In 2-month-old mutant plants, iron chlorosis was observed on young leaves and a potassium deficiency was observed on older leaves. After 1 year of growth in the greenhouse, all of the wild-type plants had survived, but only 27% (16/60) of the mutant vse plants were alive.
Thermostability of Photosynthesis of Vitis aestivalis and V. vinifera
Authors: Kadir Sorkel
Published: January 2019

High temperature adversely affects photosynthetic rates and thylakoid activities in many species, but photosynthesis response to heat stress is not well defined in grapes (Vitis L.). Genotypes within species respond differently to high temperatures, indicating a genetic variability for the trait. The objective of this study was to determine the physiological responses of two grape species to high temperature, at the whole-plant level and at the cellular level. Gas exchange, relative chlorophyll content, and chlorophyll fluorescence of intact leaves and thermostability of extracted thylakoids of the American (V. aestivalis Michx.) `Cynthiana' and European (V. vinifera L.) `Semillon', `Pinot Noir', `Chardonnay', and `Cabernet Sauvignon' wine grapes were evaluated. One-year-old vines were placed in controlled environmental chamber held at 20/15, 30/25, or 40/35 °C day/night for 4 weeks. Net CO2 assimilation (A) rate, stomatal conductance (gs), transpiration (E) rate, chlorophyll content, and chlorophyll fluorescence of intact leaves were measured at weekly intervals. Chlorophyll fluorescence of thylakoids extracted from V. aestivalis `Cynthiana' and V. vinifera `Pinot Noir' subjected to temperatures ranging from 20 to 50 °C was measured. Optimal temperatures for photosynthesis were 20/15 °C for `Cynthiana' and `Semillon' and 30/25 °C for the other three V. vinifera cultivars. The A, gs, E, chlorophyll content, and chlorophyll fluorescence values at 40/35 °C were lower in `Cynthiana' than `Pinot Noir'. In general, reduction of A coincided with decline in gs in `Cynthiana', whereas no strong relationship between A and gs was observed in V. vinifera cultivars. Variable chlorophyll fluorescence (Fv) and the quantum efficiency of photosystem II (Fv/Fm) of intact leaves for all the cultivars decreased at 40/35 °C, with severe decline in `Cynthiana' and `Cabernet Sauvignon,' moderate decline in `Semillon' and `Chardonnay', and slight decline in `Pinot Noir'. A distinct effect of high temperature on Fv and Fv/Fm of `Cynthiana' was exerted after 2 weeks of exposure. Prolonged-exposure to 40/35 °C led to 78% decrease in Fv/Fm in `Cynthiana', compared with 8% decrease in `Pinot Noir'. In general, Fv and Fv/Fm of extracted thylakoids declined as temperature increased, with more decline in `Cynthiana' than in `Pinot Noir'. Based on A rates and Fv/Fm ratios, results showed that `Cynthiana' has lower optimal temperature for photosynthesis (20/15 °C) than `Pinot Noir' (30/25 °C). Chlorophyll fluorescence responses of intact leaves and extracted thylakoids to high temperatures indicate that `Pinot Noir' possess higher photosynthetic activity than `Cynthiana'. Results of this work could be used in selection programs for the development of heat resistant cultivars in the warmest regions.
Evaluation of Altered Cucumber Plant Architecture as a Means to Reduce Phytophthora capsici Disease Incidence on Cucumber Fruit
Authors: Ando Kaori , Grumet Rebecca
Published: January 2019

Fruit rot induced by Phytophthora capsici Leonian is an increasingly serious disease affecting pickling cucumber (Cucumis sativus L.) production in many parts of the United States. The absence of genetically resistant cultivars and rapid development of fungicide resistance makes it imperative to develop integrated disease management strategies. Cucumber fruit which come in direct contact with the soil-borne pathogen are usually located under the canopy where moist and warm conditions favor disease development. We sought to examine whether variations in plant architecture traits that influence canopy structure or fruit contact with the soil could make conditions less favorable for disease development. As an extreme test for whether an altered canopy could facilitate P. capsici control, we tested the effect of increased row spacing and trellis culture on disease occurrence in the pickling cucumber `Vlaspik'. Temperature under the canopy was lowest in trellis plots, intermediate in increased spacing plots, and highest in control plots. Disease occurrence in the trellis plots was significantly lower than in other treatments, indicating that preventing fruit contact with the soil reduced disease occurrence. The effect of currently available variation in plant architecture was tested using nearly-isogenic genotypes varying for indeterminate (De), determinate (de), standard leaf (LL), and little leaf (ll) traits. Plants with standard architecture had higher peak mid-day temperatures under the canopy and greater levels of P. capsici infection; however, levels of disease occurrence were high for all genotypes. Screening a collection of ≈150 diverse cucumber accessions identified to serve as a representative sample of the germplasm, revealed variation for an array of architectural traits including main stem length, internode length, leaf length and width, and number of branches; values for `Vlaspik' were in the middle of the distribution. Plant architectures that may allow for more open canopies, including reduced branching habit and compact growth, were tested for disease incidence. One of the compact lines (PI 308916), which had a tendency to hold young fruit off the ground, exhibited lower disease occurrence. The reduced disease occurrence was not due to genetic resistance, suggesting that architecture which allows less contact of fruit with the soil could be useful for P. capsici control for pickling cucumber.
Quantitative Real-time Reverse Transcriptase-PCR Profiling of Anthocyanin Biosynthetic Genes during Orange Fruit Ripening
Authors: Cotroneo Paola S. , Russo Maria P. , Ciuni Manuela , Recupero Giuseppe Reforgiato , Piero Angela R. Lo
Published: January 2019

Genes encoding chalcone synthase (CHS), anthocyanidin synthase (ANS), and UDP-glucose-flavonoid 3-O-glucosyltransferase (UFGT), some of the enzymes of anthocyanin biosynthetic pathway, were assayed in two different experiments using quantitative real-time reverse transcriptase (RT)-PCR, in order to test their transcription levels in the flesh of blood and common orange [Citrus sinensis (L.) Osbeck] fruit, and to investigate their role in anthocyanin accumulation in the same tissue. The first experiment compared a blood orange and a common orange cultivar during seven different fruit maturation stages. This was followed by the test of 11 different genotypes at the end of the winter season. Data collected from the first experiment, over the blood orange cultivar, were statistically analyzed using the Pearson correlation coefficient. Results show that CHS, ANS, and UFGT mRNA transcripts are up- and co-regulated in the blood orange cultivar, whereas they are down-regulated in the common orange cultivar. There is evidence of correspondence between the target genes expression level and the content of the pigment assessed. The second test confirms this correlation and shows that enzyme synthesis levels and pigment accumulation, in plants grown under the same environmental conditions, are dependent on the differences occurring among the genotypes tested. These results suggest that the absence of pigment in the common orange cultivars may be caused by the lack of induction on the structural genes expression. This is the first report on the characterization of the relationships between biosynthetic genes expression and fruit flesh anthocyanin content in blood oranges.
Identification of Fluorescent AFLP and SSR Markers for Differentiation and Analysis of New Guinea Impatiens
Authors: Parks E.J. , Moyer J.W. , Lyerly J.H.
Published: January 2019

Fluorescent amplified fragment length polymorphism (F-AFLP) and microsatellites (SSRs) were used to evaluate new guinea impatiens (Impatiens hawkeri W. Bull) cultivars. Ninety-five quality-selected polymorphic fragments from 10 F-AFLP+3 primer combinations were used to evaluate 100 cultivars representing a variety of colors, forms, and breeding programs. Jaccard similarities and unweighted pair-group method of the arithmetic average (UPGMA) clustering formed a dendrogram with three cultivar groups, to a large extent clustering the cultivars by breeder with a high cophenetic correlation coefficient. A small insert genomic library was created and 442 kb of new guinea impatiens sequence was screened for repetitive motifs, resulting in 14 microsatellite markers. A subset of 46 cultivars representing five commercial breeding companies and 11 cultivar series was selected for microsatellite analysis. Seven loci were polymorphic, with two to six alleles per locus. Although both methods were equally effective in distinguishing the cultivars from one another, the topologies of the dendrograms for the two methods were different. The topology of the AFLP dendrogram reflected possible relationships based on cultivar series and breeding company, while the SSR dendrogram did not. The objectives of this research were to develop and validate both F-AFLP and SSR methodologies for new guinea impatiens, identify markers that can be reliably used for fingerprinting, and create a database for future cultivar comparisons.
Multidimensional Analysis of S-alleles from Cross-incompatible Groups of California Almond Cultivars
Authors: Barckley Kristi K. , Uratsu Sandra L. , Gradziel Thomas M. , Dandekar Abhaya M.
Published: January 2019

The California almond industry is the largest supplier of almonds [Prunus dulcis (Miller) D.A. Webb] in the United States and throughout the world. Self-incompatibility is a major issue in almond production as it greatly affects nut set. In this study, we determined full-length sequences for alleles Sa - Si, determined the genotypes of 44 California cultivars, and assigned the cultivars to cross-incompatibility groups (CIGs). Newly identified S-alleles led to an increase in the number of CIGs. A pairwise distance tree was constructed using the aligned amino acid sequences showing their similarity. Four pairs of alleles (Sc and Se, Sg and Sh, Sd and Sj, and Sb and Sf) showed high sequence similarity. Because of its simplicity, reproducibility, and ease of analysis, PCR is the preferred method for genotyping S-alleles.
Genetic Diversity in the Highbush Blueberry Evaluated with Microsatellite Markers
Authors: Boches Peter , Bassil Nahla V. , Rowland Lisa
Published: January 2019

Sixty-nine accessions representing wild and domesticated highbush blueberry (Vaccinium corymbosum L.) germplasm were genotyped using 28 simple sequence repeats (SSRs). A total of 627 alleles was detected and unique fingerprints were generated for all accessions. Suspected duplicate accessions of `Coville' and `Ivanhoe' had DNA fingerprints that were identical to `Coville' and `Ivanhoe', respectively. Genetic similarity measures placed wild and cultivated blueberries in separate groups. Northern highbush blueberries grouped among ancestral clones that were used extensively in blueberry breeding such as `Rubel' and `Stanley'. Southern highbush blueberries formed a separate group from northern highbush blueberries. The microsatellite markers used here show excellent promise for further use in germplasm identification, in genetic studies of wild Vaccinium L. populations, and for constructing linkage maps.
Reproductive Behavior of Induced Allotetraploid ×Chitalpa and In Vitro Embryo Culture of Polyploid Progeny
Authors: Olsen Richard T. , Ranney Thomas G. , Viloria Zenaida
Published: January 2019

×Chitalpa tashkentensis Elias & Wisura is a sterile intergeneric hybrid [Catalpa bignonioides Walt. × Chilopsis linearis (Cav.) Sweet]. To restore fertility in ×Chitalpa the following were evaluated: 1) oryzalin as a polyploidization agent, 2) fertility of induced polyploids, and 3) in vitro culture methods for embryo rescue of interploid crosses. Meristems of ×Chitalpa `Pink Dawn' were submerged in an aqueous solution of 150 μm oryzalin for 0, 6, 12, or 24 hours and ploidy analyzed via flow cytometry. As treatment duration increased, recovery of diploids decreased as mixoploids and shoot mortality increased. Two tetraploid shoots occurred in the 24-hour treatment. Four tetraploids and two cytochimeras were stabilized in total. Tetraploids flowered sparsely; however, cytochimeras flowered profusely and these were used to study fertility at the tetraploid level. Diploid ×Chitalpa `Pink Dawn' pollen was essentially nonviable, but cytochimera pollen stained and germinated equal to or greater than pollen of C. bignonioides and C. linearis `Bubba'. Cytochimera ×Chitalpa were selfed yielding tetraploid seedlings, crossed with C. bignonioides to yield triploids, but failed in reciprocal crosses with C. linearis `Bubba' and `Burgundy Lace'. To increase recovery of triploids, germination of triploid and tetraploid embryos was investigated, as either intact ovules or excised embryos, on Schenk and Hildebrandt (SH) basal salts supplemented with sucrose at 20, 40, and 80 g·L-1, presence or absence of 2% coconut-water, and gibberellic acid (GA3) at 0, 1, 2, or 4 μm, and harvested weekly beginning 2 weeks after pollination (WAP). Germination of triploids (cytochimera ×Chitalpa × diploid C. bignonioides) and tetraploids (selfed cytochimera ×Chitalpa) were greatest with excised embryos at 7 WAP on SH supplemented with sucrose at 20 g·L-1 and ≥1 μm GA3. Germination of triploids (diploid C. linearis × cytochimera ×Chitalpa) was <5% at 4, 5, or 6 WAP on the same medium as above. Oryzalin effectively induced polyploidy and restored fertility in ×Chitalpa `Pink Dawn'. Successful crosses between hybrid and parental taxa of different ploidy levels, coupled with embryo culture will facilitate a ×Chitalpa breeding program. Chemical names used: 4(dipropylamino)-3,5-dinitrobenzenesulfonamide (oryzalin).
Inheritance of Cross-sensitivity in Sweet Corn to Herbicides Applied Postemergence
Authors: Pataky Jerald K. , Nordby Jonathan N. , Williams Martin M. , Riechers Dean E.
Published: January 2019

Some sweet corn (Zea mays L.) hybrids and inbreds can be severely injured by applications of postemergence herbicides. An association was observed between the responses of sweet corn hybrids and inbreds to nicosulfuron and mesotrione, and F2 families derived from a cross of a sensitive (Cr1) and a tolerant (Cr2) sweet corn inbred segregated for response to these two herbicides. These observations prompted us to examine the inheritance of sensitivity in sweet corn to multiple postemergence herbicide treatments with different modes of action and to determine if there was a common genetic basis for cross-sensitivity to these herbicides. The sensitive and tolerant inbreds, progeny in the F1, F2, BC1, and BC2 generations, and BC1S1, BC2S1, F2:3 (S1:2) and F3:4 (S2:3) families were screened for responses to eight herbicide treatments. Based on segregation of tolerant and sensitive progeny and segregation of family responses, our data indicate that a single recessive gene in Cr1 conditioned sensitivity to four acetolactate synthase (ALS)-inhibiting herbicides (foramsulfuron, nicosulfuron, primisulfuron, and rimsulfuron), a 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide (mesotrione), a growth regulator herbicide combination (dicamba + diflufenzopyr), and a protoporphyrinogen oxidase (PPO)-inhibiting herbicide (carfentrazone). Based on highly significant positive correlations of phenotypic responses among BC1S1, BC2S1, F2:3, and F3:4 families, the same gene (or closely linked genes) appeared to condition responses to each of these herbicide treatments. The dominant allele also conditions tolerance to bentazon [a photosystem II (PSII)-inhibiting herbicide] although another gene(s) also appeared to affect bentazon tolerance.
Differential Expression of Genes between Storage Roots of Sweetpotato Cultivars Jewel and White Jewel
Authors: McGregor Cecilia E. , LaBonte Don R.
Published: January 2019

`White Jewel' is a yellow-and-orange fleshed spontaneous mutant of the orange-flesh sweetpotato [Ipomoea batatas (L.) Lam.] cultivar Jewel. Mutations in storage root flesh color, and other traits are common in sweetpotato. The orange flesh color of sweetpotato is due to β-carotene stored in chromoplasts of root cells. β-carotene is important because of its role in human health. In an effort to elucidate biosynthesis and storage of β-carotene in sweetpotato roots, microarray analysis was used to investigate genes differentially expressed between `White Jewel' and `Jewel' storage roots. β-carotene content calculated from a* color values of `Jewel' and `White Jewel' were 20.66 mg/100 g fresh weight (FW) and 1.68 mg/100 g FW, respectively. Isopentenyl diphosphate isomerase (IPI) was down-regulated in `White Jewel', but farnesyl-diphosphate synthase (FPPS), geranylgeranyl diphosphate synthase (GGPS), and lycopene β-cyclase (LCY-b) were not differentially expressed. Several genes associated with chloroplasts were differentially expressed, indicating probable differences in chromoplast development of `White Jewel' and `Jewel'. Sucrose Synthase was down-regulated in `White Jewel' and fructose and glucose levels in `White Jewel' were lower than in `Jewel' while sucrose levels were higher in `White Jewel'. No differences were observed between dry weight or alcohol insoluble solids of the two cultivars. This study represents the first effort to elucidate β-carotene synthesis and storage in sweetpotato through large-scale gene expression analysis.
A Musty “Off” Flavor in Nova Scotia Potatoes Is Associated with 2,4,6-Trichloroanisole Released from Pesticide-treated Soils and High Soil Temperature
Authors: Daniels-Lake Barbara J. , Prange Robert K. , Gaul Sonia O. , McRae Kenneth B. , de Antueno Roberto , McLachlan David
Published: January 2019

In Fall 2001 in Nova Scotia's Annapolis Valley (Canada), several million kilograms of processing and table-stock potatoes (Solanum tuberosum L.) were affected by a severe “musty” “off” flavor and “off” odor that persisted after cooking. 2,4,6-Trichloroanisole (TCA), a potent musty flavor/odor compound that is not known to be a potato metabolite was detected in samples of three potato lots rejected by consumers. To determine the role and source of TCA in the affected crop, samples of tubers from 30 fields were evaluated, including examination of production inputs and industry estimation of the “off” flavor, expert organoleptic assessment of flavor–odor intensity, and analytical quantitation of the TCA content of affected tubers, followed by a soil challenge to provoke TCA production. Production of “musty” potatoes was associated with unusually hot (>30 °C) soil temperatures during the 2001 growing season, and in some cases with γ-cyclohexane hexachloride (CHC) applied to control soil wireworm (putatively Limonius agonus Say). TCA quantitation and organoleptic assessment were in general agreement. Samples of soils from “idle” fields (no agricultural inputs for at least 8 years) and “production” fields (produced “off”-flavor potatoes in 2001) were subjected to several factors: 1) presence or absence of potato tubers; 2) preheating at 30 °C for 3 days, or no preheating; and followed by 3) no pesticides, or γ-CHC, chlorothalonil, chlorpyrifos, fludioxonil, imidacloprid, or linuron applied singly, or all six pesticides applied together. After incubation for 2 weeks at 22 °C day/14 °C night with a 14-hour photoperiod, solid-phase microextraction/gas chromatographic–mass spectrometric analysis revealed that untreated soils released small quantities of TCA (2.8 mol·kg−1) whereas higher quantities of TCA were present in soils treated with pesticides (3.8–6.6 mol·kg−1). The quantity of TCA released was not significantly affected by the presence or absence of potato tubers, but it was increased by preheating the soil sample, regardless of the other two factors, and by an interaction between pesticides and soil source. The quantity of TCA from both “idle” and “production” soils was highest when γ-CHC was added alone (214% and 284% of checks respectively). TCA production increased in the presence of the other five pesticides applied singly in “production” soils, but not in “idle” soils. Application of the six pesticides together increased TCA in both soils. Such an association of TCA-based “musty” “off” flavor with field soils containing γ-CHC and other pesticides combined with high soil temperature had not been reported previously.
AFLP Markers Identify Cornus florida Cultivars and Lines
Authors: Smith Naomi R. , Trigiano Robert N. , Windham Mark T. , Lamour Kurt H. , Finley Ledare S. , Wang Xinwang , Rinehart Timothy A.
Published: January 2019

Flowering dogwood (Cornus florida L.) is an important tree of forests and urban landscapes in the eastern United States. Amplified fragment length polymorphism (AFLP) markers were generated from genomic DNA of 17 cultivars and lines, and four duplicate samples of selective cultivars. Specific markers were identified for all except the following two lines and cultivar: MW94-67, MW95-12, and ‘Plena’. A dichotomous cultivar identification key was constructed based on AFLP data, and specific peaks or combinations of peaks were identified for all cultivars and lines. The key was assessed with seven anonymous (unlabeled) dogwood samples, and all unknowns except one were identified using the dichotomous key. Two of the unknown samples, ‘Cherokee Chief’ and ‘Cherokee Brave’, were difficult to distinguish using the AFLP markers. Intracultivar variation, up to 36% dissimilarity, was observed between duplicate samples of the same cultivar from different trees, suggesting that some mislabeling of trees had occurred at the nursery. The cultivar-specific AFLP markers can be used in breeding applications, patent protection, and in future projects, such as mapping the C. florida genome.
A Comparison of Return Bloom and Nonstructural Carbohydrates, Nitrogen, and Potassium Concentrations in Moderate and Severe Alternate-bearing Pecan Cultivars
Authors: Rohla Charles T. , Smith Michael W. , Maness Niels O. , Reid William
Published: January 2019

The most significant horticultural problem facing pecan producers is alternate bearing. Four pecan [Carya illinoinensis (Wangenh.) C. Koch] cultivars were chosen, two with low to moderate and two with severe alternate-bearing tendencies, to compare selected characteristics related to irregular bearing. The cultivars were Colby and Peruque (low to medium alternate-bearing tendency) and Osage and Giles (high alternate-bearing tendency). Vegetative shoots and fruit-bearing shoots in the terminal and lateral position on 1-year-old branches were tagged in October, and flowering was determined the next spring. Shoot and root samples were collected while dormant and then analyzed for organically bound nitrogen (N), potassium (K), and nonstructural carbohydrate concentrations. As expected, ‘Colby’ and ‘Peruque’ had a lower alternate-bearing tendency than ‘Giles’ and ‘Osage’. Cultivars with a low alternate-bearing tendency had a larger return bloom on the bearing shoots in the terminal position than the other shoot types. Cultivars with a high alternate-bearing tendency had a lower return bloom on bearing terminal shoots than vegetative shoots. Bearing shoots in the lateral position usually had a lower return bloom than the other shoot types regardless of cultivar. Neither root nor shoot N, K, or nonstructural carbohydrate concentrations appeared to be closely related to the alternate-bearing characteristics of the four cultivars. The unique characteristic identified for low alternate-bearing cultivars was their ability to produce as many or more flowers and flowering shoots the next year on previously bearing terminal shoots compared with previously vegetative shoots. In high alternate-bearing cultivars, return bloom of bearing terminal shoots was suppressed relative to their vegetative shoots.
Heat-induced Leaf Senescence and Hormonal Changes for Thermal Bentgrass and Turf-type Bentgrass Species Differing in Heat Tolerance
Authors: Xu Yan , Huang Bingru
Published: January 2019

Leaf senescence can be induced by many environmental stresses, including supraoptimal temperatures. The objectives of this study were to evaluate leaf senescence induced by heat stress for two Agrostis species contrasting in heat tolerance and to examine whether heat-induced leaf senescence in both species was associated with changes in three major senescence-related hormones: ethylene, abscisic acid (ABA), and cytokinins. Plants of heat-tolerant rough bentgrass (Agrostis scabra Willd.) and heat-sensitive creeping bentgrass (Agrostis stolonifera L.) were exposed to 35/30 °C (day/night) (high temperature) or 20/15 °C (control) for 35 d in growth chambers. Turf quality, photochemical efficiency (Fv/Fm), and the contents of two pigments (chlorophyll and carotenoid) for both species decreased under high temperature; however, heat-tolerant A. scabra exhibited delayed and less severe decline in all parameters compared with heat-sensitive A. stolonifera. Ethylene production rate increased in both species at 35 °C, but the increase was observed 21 days later in A. scabra compared with that in A. stolonifera. ABA content increased at the initiation of heat stress and then declined in both species after prolonged heat stress. However, the timing of the increase was delayed for 7 days and the highest level of ABA content was less in A. scabra (4.0 times that of the control) than that in A. stolonifera (5.9 times that of the control). Decreases in both forms of cytokinins (transzeatin/zeatin riboside and isopentenyl adenosine) were also delayed for 14 days and less pronounced in A. scabra. Correlation analysis revealed that leaf senescence induced by heat stress was negatively correlated to ethylene and ABA accumulation and positively correlated to cytokinin production. Delayed leaf senescence in A. scabra under heat stress could be related to slower and less magnitude of changes in ethylene, ABA, and cytokinins.
Assessments of CO2 Assimilation on a Per-leaf-area Basis are Related to Total Leaf Area
Authors: Righetti Timothy L. , Vasconcelos Carmo , Sandrock David R. , Ortega-Farias Samuel , Moreno Yerko , Meza Francisco J.
Published: January 2019

Net photosynthetic rates often are dependent on leaf size when expressed on a leaf-area basis (CO2 assimilation as μmol·m−2·s−1). Therefore, distinguishing between leaf-size-related and other causes of differences in net photosynthetic rate cannot be determined when data are presented on a leaf-area basis. From a theoretical perspective, CO2 assimilation expressed on a leaf-area basis (μmol·m−2·s−1) will be independent of leaf area only when total net CO2 assimilation (leaf CO2 assimilation as μmol·s−1) is linearly related to leaf area and the function describing this relationship has a nonzero y intercept. This situation was not encountered in the data sets we evaluated; therefore, ratio-based estimates of CO2 assimilation were often misleading. When CO2 assimilation data are expressed on a per-leaf-area basis (the standard procedure in the photosynthesis literature), it is difficult to determine how photosynthetic efficiency changes as leaves or plants mature and difficult to compare the efficiency of treatments or cultivars when leaf size or total plant leaf area varies.
Large Variation Found in the Phytochemical and Antioxidant Activity of Peach and Plum Germplasm
Authors: Vizzotto Marcia , Cisneros-Zevallos Luis , Byrne David H. , Ramming David W. , Okie W.R.
Published: January 2019

Nineteen peach [Prunus persica (L.) Batsch] genotypes and 45 plum (Prunus salicina Erhr. and hybrids) genotypes with different flesh and skin color were analyzed for their antioxidant content and activity. Anthocyanin content, phenolic content, and antioxidant activity were higher in red-flesh than in light-colored flesh peaches. Carotenoid content was higher in yellow-flesh peaches than in light-colored ones. Red-flesh plums generally had higher anthocyanin and phenolic contents than the other plums but not necessarily greater antioxidant capacity. The total phenolic content had the most consistent and highest correlation with antioxidant activity, indicating that it is more important in determining the antioxidant activity of peaches and plums than are the anthocyanin or carotenoid contents. In general, the wide range of phytochemical content and antioxidant activity found indicates that the genetic variability present can be used to develop cultivars with enhanced health benefits.
Comparison of Several Clustering Methods in Grouping Kale Landraces
Authors: Padilla Guillermo , Cartea María Elena , Ordás Amando
Published: January 2019

Four clustering methods were compared for classification of a collection of 148 kale landraces (Brassica oleracea L. acephala group) from northwestern Spain based on morphologic characters: the unweighted pair group method using arithmetic averages (UPGMA) and the Ward method, hierarchical cluster algorithms, and the modified location model (MLM) applied to both the UPGMA and the Ward method (UPGMA-MLM and Ward-MLM, respectively). Comparisons were based on five criteria and on subjective considerations about the structure of each method and the characteristics of the material evaluated. Although the UPGMA-MLM was superior according to the objective criteria, its slight advantage with respect to the Ward-MLM strategy did not overcome the fact that the initial UPGMA cluster generated a classification with little value. The Ward-MLM strategy generated five homogeneous groups with defined morphologic characteristics. Moreover, the Ward-MLM strategy allowed the identification of redundant landraces, which would permit the number of accessions in further critical trials to be reduced.
Time to Radicle Protrusion Does Not Correlate with Early Seedling Growth in Individual Seeds of Impatiens and Petunia
Authors: Dutt Manjul , Geneve Robert
Published: January 2019

Impatiens (Impatiens wallerana Hooker F.) and petunia (Petunia ×hybrida Hort. Vilm.) seeds were imaged using a flat-bed scanner interfaced with a personal computer programmed to capture images every hour. Images were used to measure time to radicle protrusion and seedling growth. Time to radicle protrusion was calculated as time to 50% germination or as actual germination for each seed. Seedling growth after germination was calculated from linear regression of growth over time. Radicle protrusion and seedling growth were evaluated as indicators of seed vigor. Both were good indicators of seed vigor in impatiens seed lots. These measurements of vigor were highly correlated for each impatiens seed lot and for pooled seed lots. However, there was little or no correlation between time to radicle protrusion and seedling growth on an individual seed basis. The relationship between germination speed and seedling growth rate observed in impatiens was confirmed in two petunia seed lots. This study supports the use of time to radicle emergence and seedling growth as good indicators of seed vigor. However, it appears that different aspects of seed vigor may be measured by these indicators because there was no relationship between time to radicle protrusion and seedling growth rate on an individual seed basis.
The Effect of Temperature and Mean Cumulative Daily Light Intensity on Fruiting Behavior of Greenhouse-grown Tomato
Authors: Uzun Sezgin
Published: January 2019

Determinations were made of the effect of mean daily temperature and cumulative daily light intensity related to planting date on fruiting behavior of greenhouse-grown tomato (Lycopersicon esculentum Mill.). Time to first flowering (FT), flower bud number per cluster (BN/C), fruit number per cluster (FN/C), mean fruit weight, fruit growth period (FGP), and fruit production rate (FPR) in tomato were plotted against mean daily temperature (11 to 28 °C) and mean cumulative daily light intensity (2 to 8 MJ·m−2·d−1) obtained from different planting dates. The FT was negatively related to mean daily temperature at any given mean cumulative daily light intensity. Mean cumulative daily light intensity had a negative sharp and slight curvilinear relationship to FT at lower and higher mean daily temperatures, respectively. At the highest cumulative daily light intensity, BN/C was the greatest at the lowest mean daily temperature, whereas at lower cumulative daily light intensities, BN/C was curvilinearly related to mean daily temperature with the optimum mean daily temperature for BN/C between 13 and 19 °C. Mean cumulative daily light intensity had a positive curvilinear relationship to BN/C at any given mean daily temperature. FN/C increased linearly with mean cumulative daily light intensity with a steeper slope at low mean daily temperatures. At each cumulative daily light intensity, FN/C declined curvilinearly with mean daily temperature. Mean fruit weight was curvilinearly related to mean daily temperature at all mean cumulative daily light intensities. Mean fruit weight was greatest at the highest mean cumulative daily light intensities. There was a curvilinear relationship between mean cumulative daily light intensity and FGP at all mean daily temperatures. The FGP increased curvilinearly as mean daily temperature and mean cumulative light intensity increased. There was a curvilinear increase in FPR with mean cumulative daily light intensity at any given mean daily temperatures. Mean daily temperature also had a curvilinear effect on FPR such that FPR increased up to 25 °C for the lowest cumulative daily light intensity and 22 °C for the highest cumulative daily light intensity and declined thereafter as mean daily temperature increased. Optimum mean daily temperatures for FPR declined as mean cumulative daily light intensity rose. It can be said that the relationships produced in this study can be incorporated into the climate control and fertigation programs of greenhouse tomatoes.