bluuebunny/crossref_metadata_2025 huggingface dataset:
Sprouting Broccoli Accumulate Higher Concentrations of Nutritionally Important Metabolites under Narrow-band Light-emitting Diode Lighting
Authors: Kopsell Dean A. , Sams Carl E. , Barickman T. Casey , Morrow Robert C.
Published: January 2019

Previous research in our group demonstrated that short-duration exposure to narrow-band blue wavelengths of light can improve the nutritional quality of sprouting broccoli (Brassica oleacea var. italica) microgreens. The objective of this study was to measure the impact of different percentages of blue light on the concentrations of nutritional quality parameters of sprouting broccoli microgreens and to compare incandescent/fluorescent light with light-emitting diodes (LEDs). Microgreen seeds were cultured hydroponically on growing pads under light treatments of: 1) fluorescent/incandescent light; 2) 5% blue (442 to 452 nm)/95% red (622 to 632 nm); 3) 5% blue/85% red/10% green (525 to 535 nm); 4) 20% blue/80% red; and 5) 20% blue/70% red/10% green in controlled environments. Microgreens were grown at an air temperature of 24 °C and a 16-hour photoperiod using a light intensity of 250 μmol·m−2·s−1 for all light treatments. On emergence of the first true leaf, a nutrient solution of 42 mg·L−1 nitrogen (N) (20% Hoagland’s #2 solution) was used to submerge the growing pads. Microgreens were harvested after 20 days under the light treatments and shoot tissues were processed and measured for nutritionally important shoot pigments, glucosinolates, and mineral nutrients. Microgreens under the fluorescent/incandescent light treatment had significantly lower shoot fresh mass than plants under the 5% blue/95% red, 5% blue/85% red/10% green, and the 20% blue/80% red LED light treatments. The highest concentrations of shoot tissue chlorophyll, β-carotene, lutein, total carotenoids, calcium (Ca), magnesium (Mg), phosphorus (P), sulfur (S), boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn), glucoiberin, glucoraphanin, 4-methoxyglucobrassicin, and neoglucobrassicin were found in microgreens grown under the 20% blue/80% red light treatment. In general, the fluorescent/incandescent light treatment resulted in significantly lower concentrations of most metabolites measured in the sprouting broccoli tissue. Results from the current study clearly support data from many previous reports that describe stimulation of primary and secondary metabolite biosynthesis by exposure to blue light wavelengths from LEDs.
Effects of Summer Pruning and Cropload on Summer and Winter Bud Carbohydrates in Sweet Cherry
Authors: Measham Penelope F. , Quentin Audrey G. , MacNair Nicholas
Published: January 2019

Orchard management practices have the potential to influence carbohydrate supply to storage organs, including buds. This study was designed to assess if bud carbohydrates could be manipulated by orchard practices in sweet cherry (Prunus avium). Additionally, we investigated the impact of any such changes on subsequent bud burst and fruit quality the next season. We examined the effect of pruning at different fruit growth stages and cropload on summer and winter bud non-structural carbohydrates (NSCs) and on fruit quality at harvest the next summer in two cultivars. Buds were collected postharvest in summer and after the onset of dormancy in winter, and individual soluble sugars and starch were extracted. The next growing season, flower number and fruit set were recorded. When fruit reached full maturity, fruit were harvested for quality assessment. We observed qualitative changes in NSCs from buds collected in summer and winter. Pruning significantly reduced available NSCs in late summer buds but made little difference by winter; only early pruning showed slight changes in sucrose and glucose. However, early pruning positively influenced the next season’s fruit grade. High cropload resulted in higher NSCs in winter buds than the low cropload. Significant changes in sucrose from summer to winter were observed, and levels of sucrose in the buds differed between cultivars. Different levels of winter bud sucrose between cultivars corresponded to different rates of bud burst. Although pruning was able to manipulate NSCs in buds within a few weeks, these changes were not sufficient to influence the rate of bud burst within a cultivar, but pruning did influence fruit quality in the next season.
Isolation and Characterization of a Class III Peroxidase cDNA from Cucumber under Salt Stress
Authors: Fan Huai-Fu , Chen Wen , Yu Zhou , Du Chang-Xia
Published: January 2019

Salt stress reduces the fresh weight, dry weight, and relative growth rate of cucumber (Cucumis sativus) seedlings and results in serious quality loss in cucumber production. Our previous study indicated that the netting-associated peroxidase (CsaNAPOD) protein in cucumber seedling roots was induced by salt stress. Here, we amplified the coding sequence of CsaNAPOD from a cDNA isolated from the roots of cucumber seedlings. Sequence analysis indicated that the coding sequence of CsaNAPOD is 1035 bp, encoding a deduced protein of 344 amino acids, with a predicated molecular weight of 37.2 kD and theoretical isoelectric point of 5.64. The deduced amino acid sequence of CsaNAPOD showed high sequence similarity to peroxidases (PODs) from other plant species. Moreover, CsaNAPOD possesses the typical sequence structures of class III PODs and indicated that CsaNAPOD belongs to this subfamily. CsaNAPOD was highly expressed in the roots and was weakly expressed in the stems and leaves of cucumber seedlings. Salt stress significantly increased the expression of CsaNAPOD in the leaves during the entire experimental period compared with the control, and the expression of CsaNAPOD in roots was reduced at 6 hours and induced at 48 and 72 hours by salt treatment. In stems, the expression of CsaNAPOD declined at 48 and 72 hours as a result of the salt treatment compared with the control. These results indicate that the expression of CsaNAPOD responded to salt stress in cucumber seedlings, and the expression patterns under salt stress in different tissues were not identical. Our research suggests that CsaNAPOD may have potential function during the plant response to salt stress.
Midday Stem Water Potential Values Needed to Maintain Photosynthesis and Leaf Gas Exchange Established for Pecan
Authors: Othman Yahia , VanLeeuwen Dawn , Heerema Richard , St. Hilaire Rolston
Published: January 2019

Demand for New Mexico’s limited water resources coupled with periodic drought has increased the necessity for tree water status monitoring to guide irrigation scheduling of pecan (Carya illinoinensis) orchards. The objectives of this study were to assess the impact of water status developed during the flood irrigation dry-down cycles on photosynthesis (Pn), and gas exchange [stomatal conductance (gS) to H2O (gH2O), transpiration (E), and intercellular CO2 (ci)] and to establish values of midday stem water potential (Ψsmd) that are needed to maintain Pn and gas exchange of pecan. We conducted the study simultaneously on two southern New Mexico mature pecan orchards from 2011 through 2013. Flood irrigation as determined by grower practice was used on both orchards and Pn, gH2O, E, and ci were assessed at Ψsmd of –0.4 to –2.0 MPa. Photosynthesis and gas exchange were higher in pecan trees shortly after irrigation than trees exhibiting water deficit near the end of a flood irrigation dry-down cycle. The decline in Pn was markedly noticeable when Ψsmd dropped below –0.9 MPa. We attributed the reduction in Pn mostly to stomatal limitation. The decline in Pn and gH2O exceeded 50% when Ψsmd ranged from –1.5 to –2.0 MPa. For those reasons, we recommended that pecan orchards be maintained at Ψsmd higher than –0.90 MPa to prevent significant reductions in carbon assimilation and gas exchange.
Nuclear and Cytoplasmic DNA Sequence Data Further Illuminate the Genetic Composition of Leyland Cypresses
Authors: Kou Yi-Xuan , Shang Hui-Ying , Mao Kang-Shan , Li Zhong-Hu , Rushforth Keith , Adams Robert P.
Published: January 2019

Leyland cypress [×Hesperotropsis leylandii (A.B. Jacks. & Dallim.) Garland & G. Moore, Cupressaceae] is a well-known horticultural evergreen conifer in the United Kingdom, United States, Australia, New Zealand, and other countries. As demonstrated by previous studies, this taxon is a hybrid between alaska (nootka) cypress [Callitropsis nootkatensis (D. Don) Oerst. ex D.P. Little] and monterey cypress [Hesperocyparis macrocarpa (Hartw. ex Gordon) Bartel]. However, the genetic background of leyland cypress cultivars is unclear. Are they F1 or F2 hybrids or backcrosses? In this study, six individuals that represent major leyland cypress cultivars and two individuals each of its two putative parental species were collected, and three nuclear DNA regions (internal transcribed spacer, leafy and needly), three mitochondrial (mt) DNA regions (coxI, atpA, and rps3), and two chloroplast (cp) DNA regions (matK and rbcL) were sequenced and analyzed. Sequencing results of nuclear DNA regions revealed that leyland cypress cultivars consist of putative F1 and F2 hybrids as well as backcrosses. Analysis of the cp and mt DNA from six cultivars of leyland cypress revealed that their cytoplasmic (cp and mt) genomes came from alaska cypress. Our findings will provide important instructions and background knowledge on the management of these major leyland cypress cultivars as well as future studies. Meanwhile, alaska cypress and monterey cypress may have diverged with each other ≈46 million years ago. The fact that they can produce fertile hybrids indicates that hybridization events may have played an important role in the evolutionary history of the cypress family (Cupressaceae).
Feasibility of Genome-wide Association Analysis Using a Small Single Nucleotide Polymorphism Panel in an Apple Breeding Population Segregating for Fruit Skin Color
Authors: Lozano Lidia , Iglesias Ignasi , Micheletti Diego , Troggio Michela , Kumar Satish , Volz Richard K. , Allan Andrew C. , Chagné David , Gardiner Susan E.
Published: January 2019

Single-nucleotide polymorphisms (SNPs) have been used for a range of genetic studies and are now starting to be applied for marker-assisted selection in plant breeding programs. To identify SNP markers associated with red fruit skin color, we conducted a genome-wide association (GWA) analysis in an apple (Malus ×domestica Borkh.) breeding population comprising 94 phenotyped individuals using a 384-plex SNP assay. Linkage disequilibrium (LD) analysis indicated that LD extends over a long physical distance in the population (17 Mbp), indicating that a small number of generations separates the individuals. No significant association of anthocyanin content, overcolor, and colorimetric measures (a*, b*, L*, a/b*, and hue angle) with a marker was identified, although the apple fruit skin color locus has been previously located on apple linkage group 9. Our trial of a small SNP panel for GWA in apple breeding material has demonstrated the limitation of this approach for marker trait association.
Solute Transport through a Pine Bark-based Substrate under Saturated and Unsaturated Conditions
Authors: Hoskins Tyler C. , Owen James S. , Fields Jeb S. , Altland James E. , Easton Zachary M. , Niemiera Alex X.
Published: January 2019

An understanding of how dissolved mineral nutrient ions (solutes) move through pine bark substrates during the application of irrigation water is vital to better understand nutrient transport and leaching from containerized crops during an irrigation event. However, current theories on solute transport processes in soilless systems are largely based on research in mineral soils and thus do not necessarily explain solute transport in soilless substrates. A study was conducted to characterize solute transport through a 9 pine bark:1 sand (by volume) substrate by developing and analyzing breakthrough curves (BTCs). Columns filled with pine bark substrate were subjected to the application of a nutrient solution (tracer) and deionized water under saturated and unsaturated conditions. Effluent drained from the columns during these applications was collected and analyzed to determine the effluent concentration (C) of the bulk ions in solution through electrical conductivity (EC) and nitrate (NO3–), phosphate, and potassium (K+) concentrations. The BTCs were developed by plotting C relative to the concentration of the input solution (Co) (i.e., relative concentration = C/Co) as a function of the cumulative effluent volume. Solutes broke through the column earlier (i.e., with less cumulative effluent) and the transition from C/Co = 0 to 1 occurred more abruptly under unsaturated than saturated conditions. Movement of the anion, NO3–, through the substrate was observed to occur more quickly than the cation K+. Throughout the experiment, 37% of the applied K+ was retained by the pine bark. The adsorption of K+ to pine bark cation exchange sites displaced calcium (Ca2+) and magnesium (Mg2+), of which the combined equivalent charge accounted for 43.1% of the retained K+. These results demonstrate the relative ease that negatively charged fertilizer ions could move through a pine bark substrate while solution is actively flowing through substrate pores such as during irrigation events. This approach to evaluating solute transport may be used in horticultural research to better understand how mineral nutrients move through and subsequently leach from soilless substrates during irrigation. Expanding this knowledge base may lead to the refinement of production practices that improve nutrient and water use efficiency in container nurseries.
Genetic Variation and Heritability Estimates for Indirect Measures of Freezing Tolerance during Fall Acclimation in Asparagus
Authors: Kim Jaejoon , Wolyn David J.
Published: January 2019

Winterhardiness is an important trait for asparagus (Asparagus officinalis) cultivars grown in temperate climates. Several biochemical and physiological parameters are correlated with the acquisition of freezing tolerance during cold acclimation in the fall and could be used as indirect measures for selection in a breeding program. Genetic variation was assessed before and after fall acclimation in August and November, respectively, for freezing tolerance attributes in 18 asparagus hybrids and 24 clones, which included male, supermale, and female genotypes. Fern chlorophyll and rhizome sucrose concentrations and storage root and rhizome percentage water decreased, whereas the concentrations of storage root proline, glucose and sucrose, and rhizome proline and high-molecular-weight fructan increased during the fall. Germplasm did not differ in August but significant variation was observed in November for most parameters, indicating genotype-specific responses to fall acclimation and the acquisition of traits associated with freezing tolerance. Narrow-sense heritability estimates were significant for fern chlorophyll, storage root proline, and rhizome glucose and sucrose concentrations. With significant genetic variation and heritability, breeding to improve freezing tolerance could be possible with indirect selection measures.
Amplified Fragment Length Polymorphism Fingerprinting to Identify Genetic Relatedness among Lychee Cultivars and Markers Associated with Small-seeded Cultivars
Authors: Pathak Ashish K. , Singh Sudhir P. , Tuli Rakesh
Published: January 2019

Amplified fragment length polymorphism (AFLP) was used to assess genetic relatedness among 23 popular commercial cultivars of lychee (Litchi chinensis) and identify the markers associated with small-seeded cultivars. A combination of three primer pairs with high discriminatory ability was selected for resolving the identity of lychee cultivars. The marker system resolved the instances of synonymies and homonymies. The two cultivars, Dehrarose and Dehradun, whose names are often used interchangeably, could be discriminated by AFLP. A cultivar, Calcuttia (H), grown in the Punjab region was found genetically very similar to China (M) of Bihar region in India, suggesting that both could be the same clone. A number of cultivars with contrasting seed size were included in the study. The cultivars Bedana, Seedless Late, and China were positioned in one group, unlike the grouping previously reported based on morphological traits. The AFLP fingerprinting revealed five marker fragments exclusive to the genotypes, which bear fruit with small seed and large pulp.
Phenotypic and Genotypic Analysis of a U.S. Native Fine-leaved Festuca Population Reveals Its Potential Use for Low-input Urban Landscapes
Authors: Staub Jack E. , Robbins Matthew D. , Ma Yingmei , Johnson Paul G.
Published: January 2019

Continued reduction in limited natural resources worldwide increasingly necessitates the incorporation of low-maintenance and low-input plant materials into urban landscapes. Some fine-leaved Festuca grass species have been used in formal gardens and native urban landscapes because of their inherent tolerance to abiotic stresses, but native, ornamental types (tall and non-spreading with multicolored culms and panicles) are not common in landscapes of the western United States. A native fine-leaved Festuca collection made in Montana (designated FEID 9025897) by the U.S. Natural Resources Conservation Services possesses such ornamental characteristics but has not been evaluated for its horticultural potential. Therefore, a study was designed to assess its phenotypic and genotypic attributes by cloning 270 FEID 9025897 plants and evaluating them along with native F. idahoensis and F. ovina PIs (five) and commercial checks (five) for genetic diversity and plant morphology for 2 years (2010–11). Plant genetic constitution was determined using amplified fragment length polymorphism (AFLP) analysis. Plant height, width, biomass, relative vigor (visual rating of 0 = dead to 5 = green, abundant growth), persistence (number of plants alive per plot), and regrowth after clipping (visual rating of 0 = none to 5 = most) were estimated by evaluation of plants under replication at Hyde Park, UT. Based on AFLP-based coancestry analysis, FEID 9025897 plants possessed considerable genetic affinities with F. idahoensis. Morphological traits as averaged over both years varied in height (13.9 to 105.0 cm), width (9.9 to 66.2 cm), biomass (0 to 170.4 g), vigor (0.2 to 4.7), persistence (0 to 3.9), and regrowth (0 to 4.0). Based on these differences, 19 (7%) FEID 9025897 plants were identified for their ornamental potential that possessed multicolored (red, orange, and yellow) culms and varied in morphology with 2-year means of height (79.8 cm), width (45.2 cm), biomass (88.5 g), vigor (2.9), persistence (1.8), and regrowth (3.7).
Pollen Tube Growth and Double Fertilization in Camellia oleifera
Authors: Gao Chao , Yuan Deyi , Yang Ya , Wang Bifang , Liu Dongming , Zou Feng
Published: January 2019

Camellia oleifera is an important plant species that produces edible oils. Understanding the double fertilization of this plant is critical for studies concerning crossbreeding, self-incompatibility, and the biological mechanisms underlying hybridization. We aimed to characterize pollen tube growth and double fertilization in C. oleifera. The female and male parent cultivars (Huashuo and Xianglin XLC15, respectively) were used for artificial pollination. Growth of the pollen tube in the style, ovary, and ovule from pollination to fertilization and the cytological characteristics of female and male gamete fusion during double fertilization were observed using fluorescence and scanning electron microscopy (SEM). Numerous pollen grains germinated 2 to 4 hours after pollination. The pollen tubes entered the interspaces between the papillar cells, grew along the stylar canal, and aggregated at the one-third site of the style. They grew in the gradually narrowing stylar canal, entering the locule. The tubes turned 90° and entered the embryo sac through the micropyle; subsequently, they entered a degenerated synergid, where the spermatids were released. One sperm nucleus fused with the polar nucleus, forming the primary endosperm nucleus, whereas the other sperm fused with the egg, forming the zygote. The polar nucleus was fertilized earlier than the egg. Double fertilization of C. oleifera is characterized as pre-mitotic gametogony. The current results lay a theoretical foundation for studies concerning the crossbreeding and embryology of C. oleifera and provide fundamental data concerning the reproductive biology of the genus Camellia.
The Effects of Propagation Techniques on Cell Wall Chemistry and Wood Anatomy in Micropropagated and Grafted Plants of the Dutch Elm Hybrid ‘Dodoens’
Authors: Ďurkovič Jaroslav , Kačík František , Mamoňová Miroslava , Kardošová Monika , Longauer Roman , Krajňáková Jana
Published: January 2019

Determination of wood anatomy traits and the chemical attributes of plant cell walls is of great importance for the evaluation of both the effects of hybridization and the results of breeding strategies within the genus Ulmus, because these are both aimed at an enhanced tolerance to dutch elm disease (caused by Ophiostoma ulmi and O. novo-ulmi) and to the improvement of trees having desired mechanical properties. The objective of this study was to determine whether the routinely applied vegetative propagation techniques of in vitro micropropagation or grafting would result in any change to lignin monomer composition and content, macromolecular traits of cellulose, neutral sugar composition, or the vascular and fiber anatomy traits in the stems of the dutch elm hybrid cultivar Dodoens (i.e., open-pollinated Ulmus glabra ‘Exoniensis’ × U. wallichiana P39). Propagation techniques appeared to have no direct effect on lignin monomer composition. The differences in the relative proportion of guaiacyl units in lignin between the stock types were not significant, showing that no advantage could be attributed to either stock type toward an enhanced tolerance to dutch elm disease. The micropropagated plants reached significantly higher values for 13 traits (32.5%), primarily associated with the relative proportion of d-glucose and the macromolecular traits of cellulose to compensate for a lower content of holocellulose. The grafts reached higher values for 10 traits (25%), including the relative proportions of d-xylose, d-mannose, and d-galactose. The effect of the rootstock might contribute to different amounts of these cell wall substances in the grafts. The grafts also reached a higher lignin content, which may provide minor advantages in terms of mechanical and physical properties to the cell walls of this stock type. Similarities between the stock types were found for 17 traits (42.5%). Both stock types formed compact homogeneous clusters clearly separated from each other in the multivariate wood trait analysis.
Development of Shoot Architecture of Japanese Privet in Response to Soil Moisture
Authors: Silva Dilma Daniela , Beeson Richard C. , Kane Michael E.
Published: January 2019

Bud outgrowth dynamics and their implications for shoot architecture were examined in japanese privet (Ligustrum japonicum) plants under well-irrigated [short irrigation cycle (SC)] and water-limitation [long irrigation cycle (LC)] conditions. New buds had limited sensitivity to dormancy, whereas preformed buds required more than one growing season to outgrow naturally. The first spring flush of shoot growth was mostly the result of lateral bud outgrowth, whereas latter flushes had prominent contributions of new apex buds. First flush terminal stems had mainly determinate growth (episodic). First flush lateral stems had increased occurrence of indeterminate growth (continuous). Water limitation influenced shoot architecture by enhancing apical dominance. Lateral branching was diminished 51% in LC plants compared with SC plants. As plants adapted to the stress imposed, indeterminate growth was triggered more often in meristematic regions of terminal buds of LC plants. In shoot flushes that occurred later in the stress treatment, old buds burst more frequently than the newly formed apex lateral buds. Plants under SC were more compact and better formed as an inverse triangle, whereas plants under LC had considerably less new branches and instead had long branches that would require pruning to maintain aesthetically pleasing shapes.
Gibberellin Control of Reproductive Transitions in Brassica oleracea Curd Development
Authors: Duclos Denise V. , Björkman Thomas
Published: January 2019

Cauliflower (Brassica oleracea var. botrytis) and broccoli (B. oleracea var. italica) differ in the developmental stage of the reproductive meristem at harvest. A cauliflower head is formed by arrest at the inflorescence meristem stage and broccoli at the flower bud stage, and the horticultural value of the crop depends on synchronous development across the head. In other plant species, gibberellin (GA) can promote floral development and is therefore a candidate for providing the early developmental cues that shape the curd morphology. This research investigated the effect of GAs on the two horticulturally important transitions of the reproductive meristem: initiation of the inflorescence meristem and initiation of floral primordia on the proliferated inflorescence meristems. GA is known to affect the former in many species, but effects on the latter have not been determined. It is also not known whether one or both active forms produced by the two GA biosynthetic pathways is involved in the reproductive transitions in this crop. GAs from the early-13 hydroxylation pathway (GA3) and the non-13 hydroxylation pathway (GA4+7) were applied to the shoot apical meristems of cauliflower and broccoli at three developmental stages: adult-vegetative, curd initiation, and curd enlargement. GAs applied during the adult vegetative stage caused the curd to form faster and after fewer additional nodes in both cauliflower and broccoli. GAs applied to the inflorescence meristem did not cause floral primordia to form nor did the expression of transition-associated genes change. Integrator genes BoLFY and SOC1 had constant expression over 24 hours, and meristem-identity genes BoAP1-a and BoAP1-c remained undetectable. However, GAs applied early during the reproductive phase increased bract development in cauliflower curds. This study shows that GAs from both pathways can trigger the vegetative-to-reproductive transition in both cauliflower and broccoli, resulting in earlier curd formation. However, GAs did not advance the inflorescence-meristem-to-floral-primordium transition; on the contrary, they increased bract incidence in cauliflower, a sign of reversion toward the vegetative stage, suggesting that another pathway is responsible for this second transition in cauliflower and broccoli.
Calcium Distribution during Anther Development in Oil Tea (Camellia oleifera Abel.)
Authors: Wei Dongmei , Gao Chao , Yuan Deyi
Published: January 2019

The mechanism by which calcium regulates anther development remains unclear. This study investigated the relationship between calcium distribution and anther development in oil tea (Camellia oleifera Abel.) by using the potassium antimonite technique. Before the onset of microsporogenesis, abundant minute calcium precipitates appeared on the plasma membranes of microspore mother cells. Meanwhile, numerous precipitates accumulated in the tapetal cells. After meiosis, calcium precipitates appeared in young microspores. During microspore development, calcium precipitates mainly appeared in the small vacuoles of the cytoplasm. At the late microspore stage, a large vacuole formed, and the number of precipitates in the microspore decreased. The number of precipitates in the tapetal cells decreased as microsporogenesis proceeded. Then, calcium precipitates in the bicellular pollen cytoplasm again increased in number. During bicellular pollen development, the number of calcium precipitates decreased. As the pollen grains matured, only a few calcium precipitates were evident in the pollen cytoplasm. The results of this study, which show the spatial and temporal features of calcium distribution during the anther development of C. oleifera, suggest that calcium distribution is related to anther development.
Influence of Water and Nitrogen Stress on Stem Sap Flow of Tomato Grown in a Solar Greenhouse
Authors: Qiu Rangjian , Du Taisheng , Kang Shaozhong , Chen Renqiang , Wu Laosheng
Published: January 2019

Accurate measurement of crop water use under different water and nitrogen (N) conditions is of great importance for irrigation scheduling and N management. This research investigated the effect of water and N status on stem sap flow of tomato (Solanum lycopersicum) grown in an unheated solar greenhouse in northwest China. A water experiment included sufficient water supply (T1) based on in situ water content measurement, two-thirds T1 (T2) and half T1 (T3) under a typical N application rate (N1); i.e., 57.4 g·m−2 N. The N experiment included N1, two-thirds N1 (N2), and half N1 (N3) under T2 irrigation. Results showed that deficit water supply reduced the stem sap flow by 22.1% and 42.8% in T2 and T3, respectively, compared with T1. The average daily stem sap flow between N1 and N2 was similar, and both were higher than that of N3. Significant differences between N1 or N2 and N3 were only observed on four dates (totally 34 days). Nighttime stem sap flow accounted for 6.0% to 6.9% of the daily value for the water treatments and 5.7% to 8.5% of the daily value for the N treatments. No significant differences for nighttime stem sap flow were found among water and N treatments. The daily stem sap flow was significantly and positively correlated with solar radiation, air temperature, vapor pressure deficit, and reference evapotranspiration under the water and N experiments. The slopes of the regression equations between the daily stem sap flow and these parameters were lower when soil water availability was limited, whereas the slopes of the regressions had no significant differences among N treatments. A parabolic relationship between the ratio of the daily stem sap flow of water deficit treatments to that of T1 and soil relative extractable water content was observed.
Eastern Filbert Blight Resistance in Hazelnut Accessions ‘Culplà’, ‘Crvenje’, and OSU 495.072
Authors: Colburn Brooke C. , Mehlenbacher Shawn A. , Sathuvalli Vidyasagar R. , Smith David C.
Published: January 2019

European hazelnut (Corylus avellana L.) is a significant crop in Oregon, where 99% of United States hazelnuts are produced. Eastern filbert blight (EFB) caused by Anisogramma anomala (Peck) E. Müller is an important disease that infects the trees, reduces yield, and causes premature death. Managing the disease through cultural methods and fungicide applications is laborious and expensive, and genetic host resistance is considered the most viable option for control. Genetic resistance from ‘Gasaway’ has been used to develop resistant cultivars including Yamhill and Jefferson, but concern about the durability of this single resistance gene stimulated a search for additional sources of resistance. This study used three recently identified sources of EFB resistance: ‘Culplà’ from Spain, ‘Crvenje’ from Serbia, and OSU 495.072 from southern Russia. RAPD markers linked to resistance from ‘Gasaway’ were absent in all three accessions. Disease response was noted in segregating progenies following greenhouse or structure inoculation, and the resistance loci were mapped using microsatellite markers. In only four of the nine progenies did segregation for disease response fit the ratio of 1 resistant:1 susceptible expected for a single locus, a heterozygous resistant parent, and a dominant allele for resistance. Three progenies showed an excess of resistant seedlings while two showed a deficiency of resistant seedlings. The reciprocal translocations reported in several leading hazelnut cultivars may be present in the parents of the studied progenies, and affecting the segregation ratios. Microsatellite marker A614, previously mapped to linkage group (LG) 6, was closely linked to resistance from all three sources. Maps were constructed for LG6 for each resistant parent using microsatellite markers. The three resistance loci mapped to the same region on LG6 where resistance from ‘Gasaway’ and OSU 408.040 are located. The resistance alleles in all five accessions may be the same, or more likely are a cluster of different resistance genes in the same region. Markers LG628, LG610, and LG696 will be useful to breed new hazelnut cultivars with resistance from Culplà, Crvenje, and OSU 495.072.
Combining Ability of Sweetpotato Germplasm for Yield, Dry Matter Content, and Anthocyanin Production
Authors: Todd Steven M. , Truong Van-Den , Pecota Kenneth V. , Yencho G. Craig
Published: January 2019

Interest in the potential of sweetpotato (Ipomoea batatas) for the production of industrial products is increasing. As part of an effort to evaluate the potential of sweetpotatoes for starch and anthocyanin production in the southeastern United States, a 5 × 5 North Carolina mating design II (NCII mating design) was developed to estimate the relative importance of general and specific combining abilities for dry matter (DM) content, total monomeric anthocyanin (TMA) concentration, fresh yield, and total DM and anthocyanin yields. All five traits had significant general combining abilities (GCA). Yield and DM yield had significant specific combining abilities. Significant differences among parents were observed for all traits. Yield, DM content, DM yield, and TMA yield were significantly impacted by spatial gradients within the field, but TMA concentration was not. Many trait-pairs of interest had either genotypic and/or phenotypic correlations. Phenotypic and family mean correlations among yield, DM content, and DM yield; as well as among yield, TMA, and TMA yield suggested that improving one trait will not negatively impact other traits of importance.
Physiological Integration Ameliorates Negative Effects of Water Stress in Salt-sensitive ‘C198’ Common Bermudagrass
Authors: Amombo Erick , Hu Longxing , Fan Jibiao , Hu Zhengrong , Fu Jinmin
Published: January 2019

Clonal plants can consist of connected individual ramets that enhance resource sharing through physiological integration. This integration enables the whole clone to tolerate environmental stresses. The objective of this research was to investigate the effects of physical ramet connections on the integration of antioxidant enzymes in clonal common bermudagrass (Cynodon dactylon) growing under heterogeneously distributed water; i.e., nonuniform distribution of water due to 20% polyethylene glycol (PEG 6000) treatment on some ramets and not others. The bottom, middle, upper and three fragments of clonal common bermudagrass were subjected to 20% PEG 6000 with water potential of −1.8 MPa to induce heterogeneous and homogeneous drought stress. The control was not treated with 20% PEG 6000. Within the heterogeneous treatment, water stressed clonal fragments generally had higher leaf and root antioxidant enzyme activities with respect to superoxide dismutase, catalase, peroxidase (except for root peroxidase). There was no difference in antioxidant enzyme activity within the connected clonal ramets for homogeneous treatment; i.e., three connected ramets treated with 20% PEG 6000. Osmotically stressed clonal fragments under heterogeneous environments had a lower level of malonaldehyde (MDA) compared with those in homogeneous regimes. The antioxidant enzyme integration was affected by directionality and water availability contrast. This was indicated by significant decline in MDA levels within the heterogeneous treatments as compared with homogeneous treatment, which suggested reduced lipid peroxidation. These results suggested that ramet connections facilitate integration of antioxidant enzymes within clonal plants growing in heterogeneously available water. Enzymes were integrated from clonal fragments growing in water sufficient environment to those in water stressed regimes. This enhanced reactive oxygen species scavenging capacity of the entire clone hence improved drought tolerance.
Examination of Genetic Diversity of Common Bean from the Western Balkans
Authors: Maras Marko , Pipan Barbara , Šuštar-Vozlič Jelka , Todorović Vida , Đurić Gordana , Vasić Mirjana , Kratovalieva Suzana , Ibusoska Afrodita , Agić Rukie , Matotan Zdravko , Čupić Tihomir , Meglič Vladimir
Published: January 2019

In this study, genetic diversity of 119 accessions of common bean (Phaseolus vulgaris) from five former Yugoslav republics constituting the western Balkans was assessed by 13 microsatellite markers. This set of markers has proven before to efficiently distinguish between bean genotypes and assign them to either the Andean or the Mesoamerican gene pool of origin. In this study, 118 alleles were detected or 9.1 per locus on average. Four groups (i.e., Slovene, Croatian, Bosnian, and Serbian) showed similarly high levels of genetic diversity as estimated by the number of different alleles, number of effective alleles, Shannon’s information index, and expected heterozygosity. Mildly narrower genetic diversity was identified within a group of Macedonian accessions; however, this germplasm yielded the highest number of private alleles. All five germplasms share a great portion of genetic diversity as indicated by the analysis of molecular variance (AMOVA). On the basis of the scored number of migrants, we concluded that the most intensive gene flow in the region exists in Bosnia and Herzegovina. Cluster analysis based on collected molecular data classified the accessions into two large clusters that corresponded to two gene pools of origin (i.e., Andean and Mesoamerican). We found that Andean genotypes are more prevalent than Mesoamerican in all studied countries, except Macedonia, where the two gene pools are represented evenly. This could indicate that common bean was introduced into the western Balkans mainly from the Mediterranean Basin. Bayesian cluster analysis revealed that in the area studied an additional variation exists which is related to the Andean gene pool. Different scenarios of the origin of this variation are discussed in the article.
Water Deficit Irrigation Impacts on Antioxidant Metabolism Associated with Freezing Tolerance in Creeping Bentgrass
Authors: Zhang Li-Juan , Zhong Tian-Xiu , Xu Li-Xin , Han Lie-bao , Zhang Xunzhong
Published: January 2019

Soil water deficit impacts cold acclimation and freezing tolerance in creeping bentgrass (Agrostis stolonifera L.), but the mechanisms underlying have not been well understood. The objectives of this study were to investigate the effects of deficit irrigation before and during cold acclimation on osmoprotectants, antioxidant metabolism, and freezing tolerance in creeping bentgrass. The grass was subjected to three-soil moisture levels: well-watered [100% container capacity (CC)], deficit irrigation induced-mild drought stress (60% CC), and severe drought stress (30% CC) for 35 days including 14 days at 24/20 °C (day/night) and then 21 days under cold acclimation treatment (2 °C) in growth chambers. Leaf proline and total soluble sugar (TSS) levels were higher in the grass under mild drought stress relative to that under severe drought stress. Superoxide (O2−·), hydrogen peroxide (H2O2), and malondialdehyde (MDA) content were higher in the grass under severe drought relative to that under well-watered and mild drought stress at day 35. Mild drought stress increased catalase (CAT) and guaiacol peroxidase (POD) activity, induced new isoforms and increased band intensities of superoxide dismutase (SOD), CAT, and POD during cold acclimation (days 14 to 35). No differences in osmoprotectants, antioxidant metabolism, and freezing tolerance were found between mild drought and well-watered treatments. The results of this study suggest deficit irrigation-induced mild drought stress in late fall and winter could induce accumulation of osmoprotectants and improve antioxidant metabolism, and freezing tolerance, but severe drought stress could reduce freezing tolerance of creeping bentgrass in the region with limited precipitation.
Cultivar and Seasonal Effects on Seed Oil Content and Fatty acid Composition of Cucumber As a Potential Industrial Crop
Authors: Ngure Joyce W. , Cheng Chunyan , Yang Shuqiong , Lou Qunfeng , Li Ji , Qian Chuntao , Chen Jie , Chen Jinfeng
Published: January 2019

Cucumber (Cucumis sativus) seed oil has the potential for use as an edible oil and as a pharmaceutical, cosmetic, insecticidal, and industrial product. In this study, we investigated, for the first time, the effect of cultivar and season on seed number, oil content, and fatty acid profiles as well as their proportions in different cucumber cultivars. We examined the effects of spring and autumn seasons on seed oil content and fatty acid composition in 46 cucumber cultivars and one wild species of cucumber (C. anguria) grown in greenhouse experiments in 2013 and 2014. Seed oil was determined using the Soxhlet method and fatty acids using the gas chromatography-mass spectrometry method. Seed oil content in the cucumber seeds ranged from 41.07% in ‘Hazerd’ to 29.24% in ‘Lubao’ while C. anguria had 23.3%. Fatty acids detected were linoleic (C18:2), palmitic (C16:0), oleic (C18:1), stearic (C18:0), linolenic (C18:3), behenic (C22:0), arachidic C20:0), lignoceric (C24:0), eicosenoic (C20:1), palmitoleic (C16:1), and myristic (C14:0), among other unidentified fatty acids. The results showed significant effects of cultivar genotype, growing season, and interactions on the variables examined. The content of seed oil and fatty acids differed significantly among the cultivar genotypes. Spring-grown cucumbers had higher quantities of oil than the autumn-grown cucumbers. The content of fatty acids (mainly palmitic, palmitoleic, stearic, oleic, eicosenoic, and lignoceric) also was higher in spring. In autumn there were more seeds, and higher linoleic, linolenic, and other unspecified fatty acids. The higher the oleic acid content the lower was the linoleic acid indicating a strong negative relationship in these two fatty acids. The higher the seed oil content the higher was linoleic and oleic indicating a positive relationship between the seed oil and the two fatty acids. Results of this study provide important information applicable in improving management and production of cucumber seed oil especially considering its versatility in uses. Furthermore, the wide range of fatty acids found in the studied cucumber cultivars could be used in the production of novel industrial oils through genetic engineering.
Growth and Physiological Factors Involved in Interspecific Variations in Drought Tolerance and Postdrought Recovery in Warm- and Cool-season Turfgrass Species
Authors: Yu Jingjin , Liu Mengxian , Yang Zhimin , Huang Bingru
Published: January 2019

Drought stress is one of the most important abiotic stresses limiting plant growth, while high recuperative capacity of plants from drought damages is critical for plant survival in periods of drought stress and rewatering. The objective of our study was to determine physiological and growth factors in association with drought tolerance and recuperative capacity of cool-season kentucky bluegrass (Poa pratensis cv. Excursion II) and warm-season zoysigrass (Zoysia matrella cv. Diomand), which were grown in controlled environment chambers and maintained well watered (control) or subjected to drought stress and subsequently rewatering. Compared with kentucky bluegrass, zoysiagrass maintained higher leaf hydration level during drought stress, as shown by greater relative water content (RWC), improved osmotic adjustment (OA), increased leaf thickness, and more extensive root system at deeper soil layers. Turf quality (TQ) and photosynthesis recovered to a greater level and sooner in response to rewatering for zoysiagrass, compared with kentucky bluegrass, which could be due to more rapid reopening of stomata [higher stomatal conductance (gS)] and leaf rehydration (higher RWC). The aforementioned physiological factors associated with leaf dehydration tolerance during drought and rapid resumption in turf growth and photosynthesis in zoysiagrass could be useful traits for improving drought tolerance in turfgrasses.
Sensory and Chemical Flavor Analyses of Tomato Genotypes Grown in Florida during Three Different Growing Seasons in Multiple Years
Authors: Baldwin Elizabeth A. , Scott John W. , Bai Jinhe
Published: January 2019

Thirty-eight tomato (Solanum lycopersicum L.) genotypes were analyzed for sensory attributes “sweet,” “sour,” and “overall flavor” over 7 years, one to three seasons per year (March, June, and December) as well as for physical and chemical flavor-related attributes including color, sugars, acids, and aroma volatiles (6–7 years). Principal component analysis of the data of nine genotypes showed that for harvest season, December-harvested fruit were generally associated with more acids and sourness perception and less sugars and sweetness perception and, therefore, lower overall flavor ratings compared with June-harvested fruit. March-harvested samples were intermediate. Despite the seasonal variations, there were significant differences between genotypes for sensory perception of sweetness, sourness, and flavor, between seasons for sourness and flavor, and between years for flavor, with some interactions between genotypes, seasons, and years. In addition to sugar and acid measurements, 29 aroma volatiles were evaluated in 33 genotypes over the seasons. Eleven volatiles were found to positively correlate with flavor perception and 13 enhanced flavor along with the soluble solids/titratable acidity ratio in a two-predictor model, providing aroma targets for breeders. Among the genotypes evaluated most frequently were the Florida industry standard ‘Florida 47’ and University of Florida hybrid ‘Fla. 8153’ which was released in 2006 and is now marketed as Tasti-Lee®. ‘Florida 47’ was almost always rated lower for sweet and overall flavor compared with ‘Fla. 8153’. On a 1–9 hedonic scale, where 1 was least sweet, sour, or flavorful and 9 was most sweet, sour, or flavorful, average scores over the 7 years were 3.8 and 5.1 for sweet and 4.1 and 5.7 for overall flavor for ‘Florida 47’ and ‘Fla. 8153’, respectively. Other genotypes related to ‘Fla. 8153’, including its parents, were also rated high for sweet and overall flavor compared with ‘Florida 47’ and other commercial cultivars grown in Florida. Correspondingly, sugar measurements were higher, while acid measurements were slightly lower for ‘Fla. 8153’ compared with ‘Florida 47’. Thirteen out of 29 aroma compounds showed differences between these two genotypes, with eight being higher in ‘Fla. 8153’ (including many fruity/floral notes) and four higher in Florida 47 (C-5 and C-6 aldehydes and alcohols giving green notes). This provides a useful chemical model for two genotypes that differ in flavor quality that can be exploited by breeders seeking to improve flavor.