bluuebunny/crossref_metadata_2025 huggingface dataset:
Marker-assisted Selection for Combining Resistance to Bacterial Spot and Bacterial Speck in Tomato
Authors: Yang Wencai , Francis David M.
Published: January 2019

The lack of resistance to bacterial diseases increases both the financial cost and environmental impact of tomato (Lycopersicon esculentum Mill.) production while reducing yield and quality. Because several bacterial diseases can be present in the same field, developing varieties with resistance to multiple diseases is a desirable goal. Bacterial spot (caused by four Xanthomonas Dowson species) and bacterial speck (caused by Pseudomonas syringae pv. tomato Young, Dye and Wilkie) are two economically important diseases of tomato with a worldwide distribution. The resistance gene Pto confers a hypersensitive response (HR) to race 0 strains of the bacterial speck pathogen. The locus Rx3 explains up to 41% of the variation for resistance to bacterial spot race T1 in field trials, and is associated with HR following infiltration. Both Pto and Rx3 are linked in repulsion phase on chromosome 5. We made a cross between two elite breeding lines, Ohio 981205 carrying Pto and Ohio 9834 carrying Rx3, to develop an F2 population and subsequent inbred generations. Marker-assisted selection (MAS) was applied to the F2 progeny and to F2:3 families in order to select for coupling-phase resistance. Thirteen homozygous progeny from 419 F2 plants and 20 homozygous families from 3716 F3 plants were obtained. Resistance was confirmed in all selected families based on HR in greenhouse screens using bacterial speck race 0 and bacterial spot race T1 isolates. Resistance to bacterial spot race T1 was confirmed in the field for 33 of the selected families. All selected families were also resistant to bacterial speck in the field. MAS was an efficient tool to select for desirable recombination events and pyramid resistance.
Disomic Segregation of Microsatellites in the Tetraploid Prunus serotina Ehrh. (Rosaceae)
Authors: Pairon Marie C. , Jacquemart Anne-L.
Published: January 2019

Tetraploid black cherry (Prunus serotina) is the only Prunus L. species that has commercial importance as a timber tree in North America and is well known in Europe for its invasive behavior. Inheritance studies have never been performed and it is not known whether the species is allo or autotetraploid. Six microsatellite nuclear markers were used to test the inheritance in progenies of controlled crosses. Inheritance was proven to be disomic at all loci and a typical diploid mendelian inheritance was found at two loci. A first screening of a population in the invasive range showed high number of alleles per locus (ranging from 6 to 16) and high level of observed heterozygosity (0.75 to 1). Knowing that inheritance is disomic at six microsatellite loci and that at least two of them can be treated as codominant, diploid markers will be beneficial for future genetic studies.
Characterization of Physiological and Biochemical Factors Associated with Postharvest Water Loss in Ripe Pepper Fruit during Storage
Authors: Kissinger Maalekuu , Tuvia-Alkalai Sharon , Shalom Yavin , Fallik Elazar , Elkind Yonatan , Jenks Matthew A. , Goodwin Mark S.
Published: January 2019

Fruit of pepper (Capsicum annuum L.) is hollow by nature, which limits its water reservoir capacity, and as such, small amounts of water loss result in loss of freshness and firmness, which reduce fruit quality, shelf life, and market value. In order to understand the basis for water loss from fruit, 10 pepper accessions with wide variation in water loss rate were used to study physiological and biochemical factors associated with postharvest water loss in ripe pepper fruit during storage. Postharvest water loss rate in ripe pepper fruit stored at 20 °C, and 85% relative humidity, was found to be associated with cell membrane ion leakage, lipoxygenase activity, and total cuticular wax amount. Total cuticular wax amounts were highest in the high-water-loss pepper fruit, and lowest in the low-water-loss fruit. However, total cuticle amount (isolated enzymatically and quantified gravimetrically), total cutin monomer amount, and the amount of individual cutin monomer and wax constituents (determined using gas chromatography mass spectrometry) indicated no direct association with postharvest water loss rates. Fruit fresh weight, pericarp weight, pericarp surface area, pericarp thickness, initial water content, and dry matter were highly associated with each other, but less so with water loss rate. Fruit of accessions displaying high fruit water loss rate matured and ripened earlier than fruit of accessions displaying low-water-loss rate. Cell membrane ion leakage and lipoxygenase activity were higher after storage than immediately after harvest. Pepper fruit total cuticle wax amount, lipoxygenase activity, and cell membrane ion leakage were directly related to postharvest water loss rate in pepper fruit during storage.
Salinity Tolerance of Cleopatra Mandarin and Carrizo Citrange Citrus Rootstock Seedlings Is Affected by CO2 Enrichment during Growth
Authors: García-Sánchez Francisco , Syvertsen J.P.
Published: January 2019

Three-month-old citrus rootstock seedlings of the Cl- excluder Cleopatra mandarin (Citrus reticulata Blanco) and the Cl- accumulator Carrizo citrange [C. sinensis (L.) Osb. × Poncirus trifoliata L.] were fertilized with nutrient solution with or without additional 50 mm NaCl and grown at either ambient CO2 (360 μL·L-1) or elevated CO2 (700 μL·L-1) in similar controlled environment greenhouses for 8 weeks. Elevated CO2 increased plant growth, shoot/root ratio, leaf dry weight per area, net assimilation of CO2, chlorophyll, and water-use efficiency but decreased transpiration rate. Elevated CO2 decreased leaf Ca2+ and N concentration in non-salinized Cleopatra. Salinity increased leaf Cl- and Na+ in both genotypes. Carrizo had higher concentrations of Cl-but lower Na+ in leaves than Cleopatra. Salinity decreased plant growth, shoot/root ratio, net gas exchange, water use, and root Ca+2 but increased root N in both genotypes regardless of CO2 level. Neither salinity nor elevated CO2 affected leaf chlorophyll fluorescence (Fv/Fm). Carrizo had higher Fv/Fm, leaf gas exchange, chlorophyll, N, and Ca2+ than Cleopatra. Salinity-induced decreases in leaf osmotic potential increased leaf turgor especially at elevated CO2. The increase in leaf growth at elevated CO2 was greater in salinized than in nonsalinized Carrizo but was similar in Cleopatra seedlings regardless of salt treatment. In addition, salinity decreased water-use efficiency more at elevated CO2 than at ambient CO2 in Cleopatra but not in Carrizo. Elevated CO2 also decreased leaf Cl- and Na+ in Carrizo but tended to increase both ions in Cleopatra leaves. Based on leaf growth, water-use efficiency and salt ion accumulation, elevated CO2 increased salinity tolerance in the relatively salt-sensitive Carrizo more than in the salt-tolerant Cleopatra. In salinized seedlings of both genotypes, Cl- and Na+ concentration changes in response to eCO2 in leaves vs. roots were generally in opposite directions. Thus, the modifications of citrus seedling responses to salinity by the higher growth and lower transpiration at elevated CO2 were not only species dependent, but also involved whole plant growth and allocations of Na+ and Cl-.
Polyphenolics, Ascorbic Acid, and Soluble Solids Concentrations of Strawberry Cultivars and Selections Grown in a Winter Annual Hill Production System
Authors: Del Pozo-Insfran David , Duncan Christopher E. , Yu Kristine C. , Talcott Stephen T. , Chandler Craig K.
Published: January 2019

The effects of cultivar, harvest date, and production year on the soluble solids and antioxidant phytochemical levels of 22 strawberry (Fragaria ×ananassa Duch.) genotypes grown in a winter annual hill (raised bed) production system were investigated. Fruit harvested in Jan. 2003 and 2004 were characterized by low polyphenolic content, but high concentrations of soluble solids and ascorbic acid; whereas fruit harvested in Feb. 2003 and 2004 generally had elevated polyphenolic concentrations, but lower levels of soluble solids and ascorbic acid. Annual variation in soluble solids and phytochemical composition was also observed among nine strawberry genotypes, which was likely attributable to variations in solar radiation and air temperature. `Earlibrite' was among the highest for soluble solids concentration on three of the four harvest dates, while `Carmine' was noted for its high phytochemical concentrations across harvest dates and years. The breeder selection `FL 99-117' emerged as a promising selection in terms of producing fruit with high concentrations of soluble solids and antioxidant phytochemicals.
Breaking Dormancy in Red Raspberry with Hot Water Treatment and its Effects on Cold Hardiness
Authors: Palonen Pauliina , Lindén Leena
Published: January 2019

`Maurin Makea', `Muskoka', ` Ottawa', and `Preussen' red raspberry (Rubus idaeus L.) canes were collected from the field and subjected to different hot water treatments (20, 35, 40, 45, and 50 °C) to determine if endodormancy could be removed by a near lethal stress. Estimation of days for 50% budbreak (DD50) was found useful for describing the state of bud dormancy in the samples. Bud dormancy was broken in `Ottawa' by immersing the canes in 45 °C water for 2 hours, in `Maurin Makea' by treating the canes in 40 °C water, and in `Preussen' by both 40 and 45 °C treatments. The influence of this treatment on dormancy and cold hardiness at different times of the winter was further examined using `Ottawa' raspberry. The treatment removed bud dormancy most effectively in October, when the samples were in deepest dormancy. A slight effect was observed in November, but no effect in January. During ecodormancy in February the treatment delayed budbreak. Hot water treatment reduced cold hardiness of `Ottawa' canes by 8 to 15 °C, and that of buds by 9 to 13 °C during both endo- and ecodormancy. Based on the capacity of buds and canes to reacclimate, recovery from the stress treatment was possible at temperatures ≥4 °C. Loss of cold hardiness was caused by high treatment temperature itself and was not related to breaking of dormancy in samples. This finding suggests that dormancy and cold hardiness are physiologically unconnected in raspberry.
Evidence for a Single Locus Controlling Flesh Color, Senescent Leaf Color, and Hypanthium Color in Peach
Authors: Williamson Joshua D. , Peace Cameron P. , Bliss Frederick A. , Garner David T. , Crisosto Carlos H.
Published: January 2019

The Y locus of peach [Prunus persica (L.) Batsch] controls whether a tree will produce fruit with white or yellow flesh. Flesh color has implications for consumer acceptance and nutritional quality, and improved cultivars of both flesh types are actively sought. This paper focuses on evidence that the flesh color locus also controls senescent leaf color (easily observed in the fall) and hypanthium color. In two progeny populations totaling 115 progeny plus their parents, the three traits co-segregated completely. Trees carrying the dominant allele for white flesh had yellow senescent leaves and yellow hypanthia, while homozygous recessive yellow-fleshed types exhibited orange senescent leaves and orange hypanthia. Senescent leaf color was also measured quantitatively, with major colorimetric differences observed between white-fleshed and yellow-fleshed progeny. Senescent leaf hue angle and reflected light wavelengths of 500 to 560 nm were the parameters most affected by the flesh color locus. Results were verified with 10 white-fleshed and 10 yellow-fleshed cultivars. The findings show that the Y locus in peach controls the type and concentration of carotenoids in multiple organs, including fruit, leaves, and flowers. The ability to discriminate between white and yellow flesh color using a simple visual method, applicable in plants not yet at reproductive maturity, is valuable to breeders wanting to save time, growing space, and money.
Quantitative Trait Loci for Tomato Yellow Leaf Curl Virus and Tomato Mottle Virus Resistance in Tomato
Authors: Agrama H.A. , Scott J.W.
Published: January 2019

The genetic basis of resistance to tomato yellow leaf curl virus (TYLCV) and tomato mottle virus (ToMoV) was studied in three different mapping populations of tomato (Lycopersicon esculentum Mill.). Bulked segregant analysis (BSA) was used to identify random amplification of polymorphic DNA (RAPD) markers linked to TYLCV and ToMoV resistance. Segregated RAPD markers associated with resistance were linked to morphological markers self-pruning (sp) and potato leaf (c) on chromosome 6. RAPD genetic linkage maps of chromosome 6 were constructed for each of the three populations. Common mapped markers revealed straightforward homologies between the chromosome 6 linkage group of the three populations. Multiple-QTL mapping (MQM) was used to identify quantitative trait loci (QTL) for resistance linked to chromosome 6. These revealed that the resistance against TYLCV and ToMoV was mainly explained by two QTL in two populations and one QTL in another. For all of the resistance QTL detected, the favorable allele was provided by the resistant parents. The presence of three different sources of TYLCV and ToMoV resistance, and the markers in tight linkage with them, provide a means of systemically combining multiple resistance genes. Successful cloning of the R gene from tomatoes would lead to deeper understanding of the molecular basis of resistance to TYLCV and ToMoV, and might also shed light on the evolution of resistance genes in plants in general.
Genetic and Environmental Effects on Water Use Efficiency in Peach
Authors: Glenn D. Michael , Scorza R. , Okie W.R.
Published: January 2019

Two unpruned narrow-leaf and two unpruned standard-leaf peach [Prunus persica (L.) Batsch.] selections were evaluated for physiological components related to water use efficiency {WUE [carbon assimilation (A) per unit of transpiration (T)]}. The purpose of the study was to assess the value of narrow-leaf phenotypes to improve WUE in peach and separate the environmental component of canopy geometry from the genetic components. The narrow-leaf characteristic itself did not confer improved WUE. The interception of light was a key determinant of WUE in these genotypes. Internal shading of the tree by excessive leaf area reduced daily WUE measured in gas exchange studies. Canopies that intercepted more than 75% of the photosynthetically active radiation (PAR) had reduced daily WUE. Dormant season pruning of the four genotypes lowered isotopic carbon discrimination and therefore increased seasonal WUE compared to unpruned trees. None of the genotypes had a significant correlation of seasonal WUE with leaf and fruit weight. Analysis of covariance indicated that `Bounty' and both narrow-leaf genotypes had greater leaf and fruit weight than `Redhaven' for a given level of PAR interception. `Bounty' had the least internal canopy shading of the four genotypes. Genetic differences in peach growth types can be selected for factors increasing WUE as well as increased productivity. Future work in peach breeding to improve WUE and productivity must take into consideration light interception, productivity, and WUE in an integrated manner to make real progress in the efficient use of water and light in the orchard environment.
Day and Night Temperature Differential (DIF) or the Absence of Far-red Light Alters Cell Elongation in `Celebrity White' Petunia
Authors: Bachman Gary R. , McMahon Margaret J.
Published: January 2019

`Celebrity White' hybrid petunia plants (Petunia ×hybrida Hort. Vilm-Andr.) were grown either in chambers constructed of CuSO4-filled panels acting as spectral filters removing the far-red light (-FR) or in environmental control chambers under temperature treatments of 24 °C day/18 °C night (+DIF) or 18 °C day/24 °C night (-DIF). Growth responses for plants grown under CuSO4 filter (-FR) or -DIF temperatures were similar in that both treatments resulted in decreased internode length, increased stem diameter, and decreased cell length and cell diameter in epidermal, cortical, and pith tissues. Reduced cortical cell length contributed the largest percentage to internode length reductions compared to epidermal and pith tissue for the -FR treatment while reductions in cell length of all three tissues contributed to internode reduction of -DIF-treated plants. Chlorophyll a increased for plants grown under -FR, but decreased for plants grown in -DIF when compared to the appropriate controls.
Effect of Leaf and Plant Age, and Day/Night Temperature on Net CO2 Uptake in Phalaenopsis amabilis var. formosa
Authors: Guo Woei-Jiun , Lee Nean
Published: January 2019

In this study, effects of leaf age (20 to 240 days), plant age (4, 8, and 14 months after deflasking), and various day/night temperature regimes (16 to 33 °C) on photosynthesis of Phalaenopsis amabilis L. Blume var. formosa Shimadzu (Phal. TS97) leaves were investigated. The diurnal net CO2 uptake in Phal. TS97 leaves was measured and integrated to obtain total net CO2 uptake, which represents photosynthetic efficiency in plants performing crassulacean acid metabolism (CAM). Under all conditions, Phal. TS97 leaves performed typical CAM photosynthesis and reached their highest net CO2 uptake rate, ≈6 μmol·m-2·s-1, after 3 to 4 hours in the dark under a 12-hour photoperiod. When grown under 30 °C day/25 °C night temperature, the total net CO2 uptake of leaf increased with maturation and was highest at 80 days old, 20 days after full expansion. The CAM photosynthetic capacity of mature leaves remained high after maturation and began to decline at a leaf age of 240 days. The trend was consistent with malate fixation but the highest nocturnal malate concentration was observed in 100-day-old leaves. Young leaves or leaves from small juvenile plants had higher daytime CO2 fixation compared to mature leaves or large plants, suggesting that Phal. TS97 leaves progressed from C3-CAM to CAM during the course of maturation. The second newly matured leaf from the top had the highest net CO2 fixation when the newest leaf was 8 cm in length. Although plant age did not influence total CO2 uptake in the leaf, photosynthetic efficiency of leaves in small younger plants was more sensitive to high light intensity, 340 μmol·m-2·s-1 photosynthetic photon flux. The day/night temperature of 32/28 and 29/25 °C resulted in the highest total net CAM CO2 fixation in vegetative Phal. TS97 plants than higher (33/29 °C) and lower temperatures (21/16 °C).
Osmotic Adjustment Associated with Variation in Bentgrass Tolerance to Drought Stress
Authors: DaCosta Michelle , Huang Bingru
Published: January 2019

Osmotic adjustment (OA) is a major physiological mechanism associated with maintenance of cell turgor in response to dehydration stress. The objectives of this study were to examine changes in capacity for OA in relation to plant tolerance to drought stress for two cool-season turfgrass species, creeping bentgrass (Agrostis stolonifera L.) and velvet bentgrass (A. canina L.), and to determine major solutes contributing to OA in these grass species. Plants of `L-93' creeping bentgrass and `Greenwich' velvet bentgrass were grown in a growth chamber in polyvinyl chloride (PVC) tubes (5 cm diameter, 40 cm high) filled with a 1:3 (v/v) sterilized mixture of sand and sandy loam soil. The experiment consisted of two soil moisture treatments: 1) well-watered control, irrigated three times per week to maintain soil moisture near pot capacity; and 2) drought stress, irrigation completely withheld. Velvet bentgrass exhibited higher drought tolerance compared to creeping bentgrass, as manifested by higher visual turfgrass quality (TQ) and leaf relative water content (RWC) under drought stress. Both creeping bentgrass and velvet bentgrass exhibited OA in response to drought stress; however, velvet bentgrass exhibited 50% to 60% higher magnitude of OA, which could be related to the maintenance of higher leaf RWC and TQ for greater drought duration compared to creeping bentgrass. OA for both creeping bentgrass and velvet bentgrass was associated with accumulation of water soluble carbohydrates during the early period of drought and increases in proline content following prolonged period of drought; however, inorganic ion content (Ca2+ and K+) did not considerably change under drought stress and did not seem to contribute to OA in these species.
Microsatellite Marker Development in Rose and its Application in Tetraploid Mapping
Authors: Zhang L.H. , Byrne D.H. , Ballard R.E. , Rajapakse S.
Published: January 2019

Microsatellite or simple sequence repeat (SSR) markers were developed from Rosa wichurana Crépin to combine two previously constructed tetraploid rose (Rosa hybrida L.) genetic maps. To isolate SSR-containing sequences from rose a small-insert genomic library was constructed from diploid Rosa wichurana and screened with several SSR probes. Specific primers were designed for 43 unique SSR regions, of which 30 primer pairs gave rise to clear PCR products. Seventeen SSR primer pairs (57%) produced polymorphism in the tetraploid rose 90-69 mapping family. These markers were incorporated into existing maps of the parents 86-7 and 82-1134, which were constructed primarily with AFLP markers. The current map of the male parent, amphidiploid 86-7, consists of 286 markers assigned to 14 linkage groups and covering 770 cm. The map of the female tetraploid parent, 82-1134, consists of 256 markers assigned to 20 linkage groups and covering 920 cm. Nineteen rose SSR loci were mapped on the 86-7 map and 11 on the 82-1134 map. Several homeologous linkage groups within maps were identified based on SSR markers. In addition, some of the SSR markers provided anchoring points between the two parental maps. SSR markers were also useful for joining small linkage groups. Based on shared SSR markers, consensus orders for four rose linkage groups between parental maps were generated. Microsatellite markers developed in this study will provide valuable tools for many aspects of rose research including future consolidation of diploid and tetraploid rose genetic linkage maps, genetic, phylogenetic and population analyses, cultivar identification, and marker-assisted selection.
Confirmation of `Medjool' Date as a Landrace Variety through Genetic Analysis of `Medjool' Accessions in Morocco
Authors: Elhoumaizi Mohammed Aziz , Devanand Panchanoor S. , Fang Jinggui , Chao Chih-Cheng T.
Published: January 2019

We studied 66 `Medjool' date palm (Phoenix dactylifera L.) accessions from Morocco, six varieties of dates from Egypt, and four `Medjool' accessions and one `Deglet Noor' accession from California to investigate the hypothesis that `Medjool' is a landrace variety in Morocco. We used four sets of fluorescent-labeled amplified fragment length polymorphism (AFLP) markers to examine these accessions. A total of 402 bands were generated, of which 217 were polymorphic (54.0%). The 66 `Medjool' accessions from Morocco shared a minimum of 79% genetic similarity. These results support the hypothesis that `Medjool' is a landrace variety in Morocco and it is not genetically uniform. `Medjool' is the first confirmed landrace variety of date palm in the world. This finding raises the possibility that other date palms may be landrace varieties in different growing areas. Confirmation of a landrace variety in date palm has significant implication for future date palm germplasm collection and preservation. The mechanism(s) generating the genetic variation within `Medjool' accessions remains unknown. One possibility is that spontaneous genetic changes could occur frequently within vegetative tissues like offshoots under high temperature and drought stress.
Development of Robust SCAR Markers that Distinguish the Six Cultivated Brassica Species and Subspecies of the U-triangle
Authors: Iñiguez-Luy Federico L. , Sass Michell E. , Jung Geunhwa , Johns Mitrick A. , Nienhuis James
Published: January 2019

This research describes the development of robust molecular descriptors that are reliable and easy to use (PCR-based) for the proper classification of the six cultivated Brassica L. species and subspecies that make up the U triangle. Sequence characterized amplified regions (SCAR) were derived from DNA fragments generated by randomly amplified polymorphic DNA (RAPD) primers that distinguished the U-triangle Brassica species: B. rapa L. (A, n = 10), B. nigra (L.) Koch (B, n = 8), B. oleracea L. (C, n = 9), B. juncea (L.) Czern (AB, n = 18), B. napus L. (AC, n = 19), and B. carinata Braun (BC, n = 17). The SCAR descriptors developed in this study reveal the presence-absence of a DNA fragment and sequence length polymorphisms to distinguish the three genomes (A, B, and C) of the six cultivated Brassica species. These markers should prove to be useful in revealing misclassifications at the subspecies level. The amplification of a single DNA fragment and reduced sensitivity to reaction conditions make these SCAR descriptors ideal to accurately classify and organize large numbers of cultivated Brassica accessions typically present in large germplasm collections.
Effect of Photosynthetic Photon Flux and Temperature on Floral Evocation and Development in the Vernalization-sensitive Ornamental Perennial Salvia ×superba `Blaukönigin'
Authors: Waaseth Grete , Moe Roar , Heins Royal D. , Grimstad Svein O.
Published: January 2019

Varying photothermal ratios (PTR) were supplied to Salvia ×superba Stapf `Blaukönigin' during pre-inductive vegetative development with the exception of a short germination period under uniform conditions. In addition, both unvernalized plants and plants receiving a saturating vernalization treatment of 6 weeks at 5 °C were given two photosynthetic photon flux (PPF) levels (50 or 200 μmol·m-2·s-1) during subsequent inductive 16-hour long days. There were no effects of PTR treatments during vegetative development on subsequent flowering. However, the higher PPF level during inductive long days significantly accelerated floral evocation in unvernalized plants, lowering the leaf number at flowering. The effect was practically negligent after the vernalization requirement was saturated. In a second experiment, varying periods (4, 7, 10, and 14 days or until anthesis) at a PPF of 200 μmol·m-2·s-1 during 20-hour days were given at the beginning of a long-day treatment, either with or without preceding vernalization treatment. Flowering percentage increased considerably as the period at 200 μmol·m-2·s-1 was extended compared with plants grown at a lower PPF of 50 μmol·m-2·s-1. However, the leaf number on flowering plants was not affected, except in unvernalized plants receiving the highest PPF continuously until anthesis, where leaf number was reduced by almost 50%. We propose that the PPF-dependent flowering is facilitated either by the rate of ongoing assimilation or rapid mobilization of stored carbohydrates at the time of evocation. Abortion of floral primordia under the lower PPF (50 μmol·m-2·s-1) irrespective of vernalization treatment indicates that the assimilate requirement for flower bud development is independent of the mechanism for floral evocation.
Efficacy of Indoor Plants for the Removal of Single and Mixed Volatile Organic Pollutants and Physiological Effects of the Volatiles on the Plants
Authors: Hwa Yoo Mung , Kwon Youn Jung , Son Ki-Cheol , Kays Stanley J.
Published: January 2019

Foliage plants of Hedera helix L. (english ivy), Spathiphyllum wallisii Regal (peace lily), Syngonium podophyllum Schott. (nephthytis), and Cissus rhombifolia Vahl. (grape ivy) were evaluated for their ability to remove two indoor volatile organic air pollutants, benzene and toluene. Removal was monitored when the aerial portion of plants was exposed singly to 1 μL·L-1 or to 0.5 μL·L-1 of each gas in a closed environment over 6-hour periods during the day and the night. Selected physiological processes were assessed before and immediately after treatment to determine the effect of the gases on the plants. The effectiveness of plants in the removal of air pollutant(s) varied with species, time of day, and whether the gases were present singly or as a mixture. When exposed to a single gas, S. wallisii, S. podophyllum, and H. helix displayed higher removal efficiencies (ng·m-3·h-1·cm-2 leaf area) of either gas than C. rhombifolia during the day. The efficiency of removal changed when both gases were present; H. helix was substantially more effective in the removal of either benzene or toluene than the other species, with the removal of toluene more than double that of benzene. When exposed singly, the removal of both compounds was generally higher during the day than during the night for all species; however, when present simultaneously, H. helix removal efficiency during the night was similar to the day indicating that stomatal diffusion for english ivy was not a major factor. The results indicated an interaction between gases in uptake by the plant, the presence of different avenues for uptake, and the response of a single gas was not necessarily indicative of the response when other gases are present. Changes in the rates of photosynthesis, stomatal conductance, and transpiration before and after exposure indicated that the volatiles adversely affected the plants and the effects were not consistent across species and gases. Deleterious effects of volatile pollutants on indoor plants may be critical in their efficacy in improving indoor air quality and warrant further study.
Bigtooth Maples Exposed to Asynchronous Cyclic Irrigation Show Provenance Differences in Drought Adaptation Mechanisms
Authors: Bsoul Emad , Hilaire Rolston St. , VanLeeuwen Dawn M.
Published: January 2019

Ecological traits such as an extensive range of natural distribution and tolerance to varying soil conditions, suggest that bigtooth maples (Acer grandidentatum Nutt.) could be popular landscape trees. But information on the tolerance of bigtooth maples to environmental stresses, such as drought, is virtually nonexistent. We studied physiological, growth and developmental traits of bigtooth maple plants from 15 trees native to Arizona, New Mexico, Texas, and Utah. Plants were grown in pots in a greenhouse and maintained as well-irrigated controls or exposed to drought and irrigated in cycles based on evapotranspiration. The ratio of variable to maximal fluorescence (Fv/Fm) was not different between drought-stressed and control plants, but the low Fv/Fm in plants designated as LM2 from the Lost Maples State Natural Area in Vanderpool, Tex., suggests these plants were relatively inefficient in capturing energy at PSII. Plants from another tree (LM5) originating from Lost Maples State Natural Area maintained similar predawn water potentials between drought-stressed and control plants after five cycles of drought. Plants from Dripping Springs State Park in Las Cruces, N.M., and those from LM2 had a strong, significant linear relationship between transpiration and stomatal conductance. Drought-stressed plants from Dripping Springs State Park, two plant sources from the Guadalupe Mountains in Salt Flat, Tex., designated as GM3 and GM4, and plants from trees designated as LM1 and LM2, had high relative growth rates and net assimilation rates. Drought-stressed plants from three of the four Guadalupe Mountain sources (GM1, GM3, GM4) had among the longest and thickest stems. Drought reduced shoot and root dry weight (DW). Although bigtooth maples showed several provenance differences in drought adaptation mechanisms, the lack of an irrigation effect on biomass allocation parameters such as root to shoot DW ratio and leaf area ratio implies that altered biomass allocation patterns may not be a common drought adaptation mechanism in bigtooth maples. Plants from selected provenances from the Guadalupe Mountains and Lost Maples State Natural Area in Texas, and to a lesser extent, provenances from Dripping Springs State Park in New Mexico might hold promise for selecting bigtooth maples for arid environments.
Detecting DNA Polymorphism and Genetic Diversity in a Wide Pistachio Germplasm: Comparison of AFLP, ISSR, and RAPD Markers
Authors: Kafkas Salih , Ozkan Hakan , Ak Bekir Erol , Acar Izzet , Atli Halit Seyfettin , Koyuncu Sonay
Published: January 2019

There are limited numbers of pistachio (Pistacia vera L.) cultivars in the world and their phenotypic appearance and productivity are variable. Understanding such variation would facilitate their use in cultivar breeding programs. Therefore, in this study, 69 pistachio cultivars and genotypes originating from seven countries were characterized by randomly amplified polymorphic DNA (RAPD), inter-simple sequence repeats (ISSR), and amplified fragment-length polymorphism (AFLP) markers. The results showed that all three marker systems were able to reveal variability between pistachio cultivars and genotypes. The correlation coefficients for genetic distances were statistically significant among all three molecular marker types. The correlation between RAPD and AFLP data was the highest (r = 0.73) and the value between RAPD and ISSR data was the lowest (r = 0.58). AFLP proved to be the best technique among them. ISSR and AFLP assays were reliable and produced reproducible bands. ISSR was preferred over RAPD, especially when financial investment and technical knowledge are limited. The constructed unweighted pair group method with arithmetic averages (UPGMA) dendrogram obtained from combined data separated the genotypes into two main clusters: one cluster (“Iranian”) included genotypes originating from Iran and the second cluster (“Mediterranean”) contained most other genotypes. The “Mediterranean” cluster further divided into three subclusters: one (“Siirt”) consisted of the cultivars Siirt and Hacireso with a few other selections; the second subcluster (“Turkish”) included Turkish cultivars; and the third subcluster contained Syrian, Italian, and the remaining cultivars. The closeness of the clusters was “Iranian” - “Siirt” - “Turkish”/“Syrian.” These findings reveal a new understanding in the diffusion of pistachio cultivation from its center of origin, the Iranian-Caspian region, via southeastern Turkey to Syria, the Mediterranean region of Europe, and northern Africa.
Long-term Effect of Winter Gibberellic Acid Sprays and Auxin Applications on Crop Value of `Clausellina' Satsuma
Authors: Duarte Amílcar M.M. , García-Luis Amparo , Molina Rosa Victoria , Monerri Consuelo , Navarro Vicente , Nebauer Sergio G. , Sánchez-Perales Manuel , Guardiola Jose Luis
Published: January 2019

A winter gibberellic acid (GA3) spray consistently reduced flower formation, but had a variable effect on the amount of first-grade fruit in the early harvest of `Clausellina' satsuma (Citrus unshiu Marc.), and in the long term these applications had no significant effect on the value of the crop. Auxin applications increased the amount of first grade-early harvested fruit, and increased crop value as compared to hand-thinned trees. No significant differences in yield or fruit grade could be found among the different auxin applications tried, namely an application of 20 mg·L-1 2,4-dichlorophenoxyacetic acid (2,4-D) at flowering, or applications of 25 mg·L-1 naphthaleneacetic acid (NAA), or 50 mg·L-1 2,4-dicholorophenoxypropionic acid (2,4-DP) at the end of fruitlet abscission. Apart from their effect on size, the auxin applications had only a marginal effect on fruit quality.
Timing and Temperature of Physiological Decline for Creeping Bentgrass
Authors: Pote John , Wang Zhaolong , Huang Bingru
Published: January 2019

Knowledge of the level of soil temperatures that is detrimental for shoot and root growth for cool-season grasses may help develop heat-tolerant plants and effective management practices to improve summer performance. The objectives of this study were to determine the level and duration of high temperatures in the root zone that will induce decline for various growth and physiological parameters and to compare the responses of different physiological parameters and cultivars to high root-zone temperatures. Nine creeping bentgrass [Agrostis stolonifera L. var. palustris (Huds.) Farw.] cultivars were subjected to eight root-zone temperatures (20, 21, 22, 23, 25, 27, 31, 35 °C) in water baths while exposed to a constant air temperature of 20 °C for 54 days. Root number, dry weight, and depth, active root biomass, turf quality, leaf cytokinin content, and canopy net photosynthetic rate (Pn), decreased in all nine cultivars as root-zone temperature increased from 20 to 35 °C, but the time and temperature at which the decline occurred varied for each parameter measured. Pn, cytokinin content, root number, and turf quality declined at 23, 27, 27, and 35 °C, respectively, after 28 days of exposure. Active root biomass, root number, root dry weight, turf quality, and rooting depth declined at 23, 25, 25, 25, and 35 °C, respectively, at 54 days. At a 31 °C root-zone temperature the decline in root number, cytokinin content, and turf quality occurred at 19, 37, and 47 days, respectively. The results suggest that root-zone temperatures of 23 °C or above this level were detrimental to root activities, Pn, and overall turf growth. Root and Pn decline at lower temperatures and earlier in the study than turf quality suggest that the disturbance of physiological activities of roots and leaves could lead to turfgrass quality decline at high root-zone temperatures.
Effect of Half and Whole Root Drying on Photosynthesis, Nitrate Concentration, and Nitrate Reductase Activity in Roots and Leaves of Micropropagated Apple Plants
Authors: Zhao Jun Ying , Wang Li Jun , Fan Pei Ge , Dai Zhan Wu , Hua Li Shao
Published: January 2019

Half or whole root systems of micropropagated `Gala' apple (Malus ×domestica Borkh.) plants were subjected to drought stress by regulating the osmotic potential of the nutrient solution using polyethylene glycol (20% w/v) to investigate the effect of root drying on NO3- content and metabolism in roots and leaves and on leaf photosynthesis. No significant difference in predawn leaf water potential was found between half root stress (HRS) and control (CK), while predawn leaf water potential from both was significantly higher than for the whole root stress (WRS) treatment. However, diurnal leaf water potential of HRS was lower than CK and higher than WRS during most of the daytime. Neither HRS nor WRS influenced foliar NO3- concentration, but both significantly reduced NO3- concentration in drought-stressed roots as early as 4 hours after stress treatment started. This reduced NO3- concentration was maintained in HRS and WRS roots to the end of the experiment. However, there were no significant differences in NO3- concerntation between CK roots and unstressed roots of HRS. Similar to the effect on root NO3- concentration, both HRS and WRS reduced nitrate reductase activity in drought-stressed roots. Moreover, leaf net photosynthesis, stomatal conductance and transpiration rate of HRS plants were reduced significantly throughout the experiment when compared with CK plants, but the values were higher than those of WRS plants in the first 7 days of stress treatment though not at later times. Net photosynthesis, stomatal conductance and transpiration rate were correlated to root NO3- concentration. This correlation may simply reflect the fact that water stress affected both NO3- concentration in roots and leaf gas exchange in the same direction.
Production of Sexual Hybrid Progenies for Clarifying the Phylogenic Relationship between Citrus and Citropsis species
Authors: Yahata Masaki , Kunitake Hisato , Yasuda Kiichi , Yamashita Kensuke , Komatsu Haruki , Matsumoto Ryoji
Published: January 2019

The reciprocal crosses between two citrus cultivars and Citropsis schweinfurthii (Engl.) Swing. & M. Kell. were conducted. The cross between `Nanpu' tangor {`Kiyomi' tangor (Citrus unshiu Marc. × C. sinensis Osbeck) × `Fairchild' tangerine-tangelo [clementine (C. clementina hort. ex Tanaka) × `Orlando' tangelo (C. paradisi Macf. × C. reticulata Blanco)]} and C. schweinfurthii produced some developed seeds with an average weight approximately 1/10 of that of the seeds obtained from open pollination in `Nanpu' tangor. These seeds germinated on Murashige and Tucker medium, and three and 28 seedlings were obtained from crosses using C. schweinfurthii as the female and the male parent, respectively. The absolute nuclear genome size of these seedlings [∼0.84 pg of DNA content per somatic nucleus (2C)] was intermediate of that of the `Nanpu' tangor (0.78 pg/2C) and C. schweinfurthii (0.90 pg/2C) seedlings. The chromosome counts of the young leaves revealed that they were diploids (2n = 2X = 18). Furthermore, the hybridity of the seedlings obtained from the reciprocal crosses between `Nanpu' tangor and C. schweinfurthii was confirmed by randomly amplified polymorphic DNA (RAPD) analysis and cleaved amplified polymorphic sequence (CAPS) analysis. These hybrids will be utilized as important materials for investigating the phylogenic relationships between these genera in the subfamily Aurantioideae.
Use of Highly Discriminating Morphological Characters and Isozymes in the Study of Spanish Chestnut Cultivars
Authors: Pereira-Lorenzo Santiago , Díaz-Hernández María Belén , Ramos-Cabrer Ana María
Published: January 2019

Morphological characters (six traits) and isozymes (four systems, five loci) were used to discriminate between Spanish chestnut cultivars (Castanea sativa Mill.) from the Iberian Peninsula. A total of 701 accessions (representing 168 local cultivars) were analyzed from collections made between 1989 and 2003 in the main chestnut growing areas: 31 were from Andalucía (12 cultivars), 293 from Asturias (65 cultivars), 25 from Castilla-León (nine cultivars), four from Extremadura (two cultivars) and 348 from Galicia (80 cultivars). Data were synthesized using multivariate analysis, principal component analysis, and cluster analysis. A total of 152 Spanish cultivars were verified: 58 cultivars of major importance and 94 of minor importance, of which 18 had high intracultivar variation. Thirty-seven cultivars were clustered into 14 synonymous groups. Six of these were from Galicia, one from Castilla-León (El Bierzo), four from Asturias, one from Asturias and Castilla-León (El Bierzo), and two from Asturias, Castilla-León (El Bierzo), and Galicia. The chestnut cultivars from Galicia and Asturias were undifferentiated in genetic terms, indicating that they are not genetically isolated. Overall, chestnut cultivars from southern Spain showed the least variation. Many (58%) of Spanish cultivars produced more than 100 nuts/kg; removing this low market-value character will be a high priority. The data obtained will be of use in chestnut breeding programs in Spain and elsewhere.
Effect of Jasmonates Differed at Fruit Ripening Stages on 1-Aminocyclopropane-1-Carboxylate (ACC) Synthase and ACC Oxidase Gene Expression in Pears
Authors: Kondo Satoru , Yamada Hiroko , Setha Sutthiwal
Published: January 2019

The effects of n-propyl dihydrojasmonate (PDJ), which is a jasmonic acid derivative, on 1-aminocyclopropane-1-carboxylate (ACC) synthase and ACC oxidase activities, their gene expressions, and ethylene productions in ‘La France’ pears (Pyrus communis L.) were investigated. The fruit was harvested 156 days after full bloom, stored at 4 °C for 15 days, ripened at 20 °C, and then dipped into 0.39 mm PDJ solution at the preclimacteric stage (0 day of ripening at 20 °C) or the climacteric stage (9 days of ripening at 20 °C). In the skin of the PDJ-treated fruit at the preclimacteric stage, the expressions of ACC synthase (ACS)1 and ACC oxidase (ACO)1 were higher than the expressions of those in the untreated control. Ethylene production also increased in the PDJ-treated fruit. In contrast, the accumulation of the ACS1 messenger RNA (mRNA) levels in the skin and an increase of ethylene production were observed in the untreated control fruit at the climacteric stage, although the levels of mRNAs hybridized with ACO1 were not different between the PDJ-treated fruit and untreated control. The endogenous jasmonic acid levels in the skin increased in the PDJ-treated fruit regardless of the application times of PDJ. These results indicate that ACS1 may be an ACC synthase gene that is induced by jasmonates in pears, and that system 2 ethylene may be regulated by jasmonates.
Endogenous Ethylene and Color Development in the Skin of ‘Pink Lady’ Apple
Authors: Whale Suparna K. , Singh Zora
Published: January 2019

To elucidate the temporal relationship between endogenous ethylene and color development, changes in ethylene concentration, fruit color, pigments, and flavonoids were monitored at different intervals during the development and ripening of ‘Pink Lady’ apple (Malus × domestica Borkh.), commencing from 60 days after full bloom (DAFB) in 2002 to 2003, and 7 DAFB in the 2003 to 2004 season. Concentrations of chlorogenic acid, phloridzin, catechin, epicatechin, and quercetin glycosides were significantly higher (P ≤ 0.05) during the early stages (7−60 DAFB) compared with the later stages (≥60 DAFB) of fruit growth. During fruit development, concentrations of phloridzin, catechin, epicatechin, and quercetin glycosides decreased to low and stable levels. However, the concentration of anthocyanin (cyanidin 3-galactoside) increased during maturation and ripening (≥168 DAFB), coinciding with a corresponding increase in percent red blush and endogenous ethylene concentration. Positive and significant correlations were found between ethylene and color development and between ethylene and total anthocyanin, but not the other flavonoid compounds. Ethylene therefore appears to be a key factor regulating anthocyanin biosynthesis and color development in ‘Pink Lady’ apple. However, the accumulation of other classes of flavonoids such as catechin, epicatechin, phloridzin, chlorogenic acid, and quercetin glycosides seems to be regulated independently of ethylene during fruit development and ripening.
Analysis of Ratio-based Responses
Authors: Righetti Timothy L. , Sandrock David R. , Strik Bernadine , Vasconcelos Carmo , Moreno Yerko , Ortega-Farias Samuel , Bañados Pilar
Published: January 2019

It is not appropriate to compare ratio-based expressions for different cultivars or treatments if a plot of the denominator versus the numerator of a ratio-based expression has a nonzero y-intercept and the values for either the denominators or numerators differ with cultivars or treatments. Whenever nonzero y-intercepts are encountered, the value for a ratio-based expression will be dependent on both the denominator and numerator. The “ratio problem” is demonstrated with shoot N concentration in blueberries (Vaccinium corymbosum L.) and amino acid accumulation in almonds [Prunis dulcis (Mill.) D.A. Webb]. Data were collected from the first and second growth flush of blueberry shoots on plants that were at two in-row spacings and two rates of N fertilizer. Free amino acid:total amino acid ratios were measured in dormant almond trees fertilized at different rates with and without foliar N supplements. Functions describing the relationship between dry weight and total N content in blueberry tissues have positive y-intercepts for both N fertilizer application rates. Functions describing the relationship between total amino acids and free amino acids in almond trees have a negative y-intercept. Differences attributable to fertilization rate in blueberries probably were the result of differences in N uptake and N utilization, but the effects of spacing and growth flush are indirect and can be accounted for by differences in dry weight. Likewise, effects of fertilization rate and foliar N supplement in almonds are indirect and can be accounted for by differences in the total amino acids in dormant trees. With regression one can determine if the relationship between the denominator and numerator differs for the groups or treatments being studied. When an analysis of covariance is used to account for differences in the denominators of ratio-based expressions, results are consistent with the regression analysis. When a conclusion is based on statistical differences of a ratio-based expression, it is the researcher's responsibility to determine whether these effects are direct or indirect.