bluuebunny/crossref_metadata_2025 huggingface dataset:
Lamp Type and Irradiance Level for Daylength Extensions Influence Flowering of Campanula carpatica `Blue Clips', Coreopsis grandiflora `Early Sunrise', and Coreopsis verticillata `Moonbeam'
Authors: Whitman Catherine M. , Heins Royal D. , Cameron Arthur C. , Carlson William H.
Published: January 2019

The effectiveness of cool-white fluorescent, high-pressure sodium, incandescent, and metal halide lamps for inducing flowering through daylength extensions in Campanula carpatica Jacq. `Blue Clips', Coreopsis grandiflora Hogg ex Sweet `Early Sunrise', and Coreopsis verticillata L. `Moonbeam' was compared. Lighting was delivered as a 7-hour day extension with photosynthetic photon flux (PPF) ranging from 0.05 to 2.0 μmol·m-2·s-1 following a 9-hour natural daylength. Threshold irradiance values for flowering ranged from <0.05 to 0.4 μmol·m-2·s-1, depending on species. Saturation irradiance values for Campanula carpatica `Blue Clips' and C. grandiflora `Early Sunrise' were between 0.2 ± 0.2 and 0.7 ± 0.5 μmol·m-2·s-1, and did not differ between lamps. An irradiance of 1.0 μmol·m-2·s-1 from any lamp was adequate for flowering in Coreopsis verticillata `Moonbeam'. Time to flower at irradiances above the saturation points did not differ significantly between lamp types for all species tested. Campanula carpatica `Blue Clips' and Coreopsis grandiflora `Early Sunrise' plants had significantly longer stems under incandescent lamps than in any other treatment. Coreopsis verticillata `Moonbeam' plants grown under cool-white fluorescent lamps had stems ≈10% longer than those grown under high-pressure sodium or incandescent lamps.
Nitrate Uptake and Nitrogen Use Efficiency of Two Sweetpotato Genotypes during Early Stages of Storage Root Formation
Authors: Villagarcia Margarita R. , Collins Wanda W. , Raper C. David
Published: January 2019

Soil N availability is an important component in storage root production of sweetpotato [Ipomoea batata (L.) Lam.]. A controlled-environment experiment was conducted to characterize effects of N availability on patterns of dry matter, nonstructural carbohydrates, and N accumulation, and to determine possible components of N use efficiency that vary between two genotypes of sweetpotato. Rooted cuttings of `Jewel' and MD810 were transplanted into pots filled with sand and kept in a growth chamber for 72 days. Plants were watered during the first 30 days with a complete nutrient solution that contained 14 mm NO3- and then for the next 42 days with one of three complete nutrient solution that contained either 2, 8, or 14 mm NO3-. At 30, 44, 58, and 72 days after transplanting, three plants from each cultivar and treatment combination were sampled and separated into leaves, stems plus petioles, fibrous roots, and storage roots. Each plant fraction was freeze-dried, weighed, ground, and analyzed for total N, soluble sugars, and starch. Availability of N in the substrate, which limited dry matter accumulation at 2 mm NO3-, was nonlimiting at 8 and 14 mm NO3-. In both genotypes, net assimilation rate, efficiency of N use (i.e., increments of dry matter accumulated per increment of N taken up), and proportion of dry matter allocated to storage roots were greater for N-stressed (2 mm NO3-) than N-replete (8 and 14 mm NO3-) plants. For the N-stressed plants, however, efficiency of N use was greater in MD810 than in `Jewel'. Although rate of NO3- uptake per unit fibrous root mass was similar in the two genotypes under the N stress treatment, MD810 had greater uptake rate than `Jewel' under nonlimiting availability of NO3- in the substrate. The increased rate of uptake under nonlimiting NO3- supplies apparently was related to enhanced rates of carbohydrate transport from shoots to roots. As tissue concentration of N declined in response to the lowest application of NO3-, shoot growth was limited prior to, and to a greater extent than, the photosynthetic rate. The resulting relative decline in sink activity of shoots thus presumably increased the availability of carbohydrates for transport to roots.
Selecting for Common Bacterial Blight Resistance in Common Bean: Effects of Multiple Leaf Inoculation and Detached Pod Inoculation Test
Authors: Ariyarathne H.M. , Coyne D.P. , Vidaver A.K. , Eskridge K.M.
Published: January 2019

Breeding for resistance is an important strategy to manage common bacterial blight disease caused by Xanthomonas campestris pv. phaseoli (E. Smith) Dye (Xep) in common bean (Phaseolus vulgaris L.). It is necessary to determine if prior inoculation of the first trifoliolate leaf with Xcp influences subsequent reactions in other plant organs by increasing or decreasing resistance to Xcp. It is difficult to get an accurate estimate of heritability of disease reaction in pods since environment greatly affects the heritability estimate if flowering occurs over extended time periods. Thus, the disease reaction in attached pods versus detached pods was compared. A split-split plot design with two replications (growth chambers as blocks) was used, with bean lines as the whole-plot factors, Xcp strains as subplot factors, and bacterial inoculation treatments for leaf reactions or pod treatments as split-split plot factors. The first trifoliolate leaves, later developed leaves, and attached and detached pods were inoculated. No effects of prior inoculation on the disease reactions of subsequently inoculated leaves and pods were observed, indicating that the different plant organs can be inoculated at different times. The fact that detached and attached pods showed similar disease symptoms would suggest use of the former to reduce environment variance and improve heritability estimates of resistance.
Allozyme Inheritance in Anise Hyssop [Agastache foeniculum (Pursh) Kuntze] (Lamiaceae)
Authors: Fuentes-Granados Roger G. , Widrlechner Mark P. , Wilson Lester A.
Published: January 2019

The inheritance of five allozymes was studied in anise hyssop (Agastache foeniculum) by analyzing the progeny of controlled crosses. The loci studied [Cat-1, Got-2, Pgm-2, Tpi-1, and Tpi-2] were scored by using starch gel electrophoresis. Segregation analyses of families polymorphic at each of these loci support the following hypotheses: Cat-1 is controlled by a single gene with codominant alleles; Got-2 is controlled by a single gene with codominant alleles coding for dimeric protein products; Pgm-2 is controlled by a single gene with codominant alleles coding for monomeric proteins; and Tpi-1 and Tpi-2 are each controlled by a single gene with codominant alleles coding dimeric protein products. Distorted segregation ratios were observed in some families segregating for Got-2 and Pgm-2. No linkages were detected among any of the cosegregating loci.
Localized Accumulation of Condensed Tannins Associated with Poinsettia Bract Necrosis
Authors: McAvoy Richard J. , Bible Bernard B. , Evans Michael R.
Published: January 2019

The early onset of bract necrosis in poinsettia (Euphorbia pulcherrima Willd. ex. Klotzch) is characterized by small dark-stained spots that precede the development of enlarged necrotic lesions. Electron micrographs of adaxial epidermal and subepidermal tissues with early symptoms of necrosis revealed large, electron-dense deposits in cell vacuoles. These spherical bodies resembled condensed tannins observed in the epidermal tissues of peach and apple fruit. Chemical analysis of bract tissues confirmed the presence of condensed tannins. Furthermore, there were higher concentrations of condensed tannin in bract samples with 2-mm-diameter lesions than in samples with lesions <0.5 mm (equivalent to catechin concentrations of 59 and 13 mg·g-1 fresh mass, respectively). No tannin bodies were observed in parallel samples of healthy-appearing bracts in which only trace concentrations of condensed tannins were measured (0.2 mg·g-1 fresh mass). The evidence suggests an association between condensed tannin accumulation in localized areas of the bract and the early appearance of bract necrosis symptoms.
Modified Expression of the N Gene for Southern Root-knot Nematode Resistance in Pepper at High Soil Temperatures
Authors: Thies Judy A. , Fery Richard L.
Published: January 2019

Heat stability of the N gene that confers resistance to the southern root-knot nematode, Meloidogyne incognita (Kofoid & White) Chitwood in pepper (Capsicum annuum L.), was determined at 24, 28, and 32°C. Responses of resistant bell pepper cultivars Charleston Belle and Carolina Wonder (homozygous for the N gene) and their respective susceptible recurrent backcross parents, `Keystone Resistant Giant' and `Yolo Wonder B', to M. incognita were compared. Numbers of eggs/g fresh root, reproductive factor of M. incognita, numbers of second-stage juveniles in soil, egg mass production, and root galling increased (P < 0.05) for all cultivars as temperature increased. The response of the resistant cultivars to temperature increase was less dramatic than the response of the susceptible cultivars. Both `Charleston Belle' and `Carolina Wonder' exhibited a partial loss of resistance at 28 and 32 °C. Reproduction of M. incognita was minimal on the resistant cultivars at 24 °C, but increased at higher temperatures. However, at 32 °C reproduction of M. incognita on the resistant cultivars was only 20% of that on the susceptible cultivars and root gall indices were within the range considered moderately resistant. Unlike the susceptible cultivars, the shoot dry weights of the resistant cultivars were not suppressed at 32 °C. This suggests that `Charleston Belle' and `Carolina Wonder' may be somewhat tolerant to M. incognita at high soil temperatures. Although results indicate a partial loss of resistance occurred in `Charleston Belle' and `Carolina Wonder' under high soil temperatures, resistant cultivars may be a useful component of cropping systems designed to manage M. incognita in hot climates.
Association between DNA Markers and Loci Controlling Avocado Traits
Authors: Sharon Dror , Hillel Jossi , Mhameed Samir , Cregan Perry B. , Lahav Emanuel , Lavi Uri
Published: January 2019

The detection of association between DNA markers and traits of interest in an outbred population is complicated and requires highly polymorphic markers. A genetic linkage map of avocado (Persea americana Mill.) recently generated consists of simple sequence repeat (SSR) markers as well as DNA fingerprint (DFP) and randomly amplified polymorphic DNA (RAPD) markers. These markers were used to detect putative quantitative trait loci (QTLs) of eight avocado fruit traits. Two statistical methods were used: one-way analysis of variance and interval mapping. Six traits were found to be associated with at least one of the 90 DNA markers. Based on the two statistical approaches, a putative QTL associated with the presence of fibers in the flesh, was found to be located on linkage group 3. This putative QTL was found to be associated with the SSR marker AVA04 having a high significant value (P = 4.4 × 10-8). The haplotype analysis of linkage group 3 showed a putative dominant interaction between the alleles of this locus.
Provenance Variation in Pecan
Authors: Wood Bruce W. , Grauke Larry. J. , Payne Jerry A.
Published: January 2019

An assessment of vegetative traits of pecan [Carya illinoinensis (Wangenh.) K. Koch] from a range-wide provenance collection indicated the existence of at least two distinct populations within the native range (i.e., provenances north of Texas vs. provenances in Texas and Mexico). Southern most provenances generally broke bud earlier, retained foliage later in the fall, grew larger in height and trunk diameter, had narrower leaflet droop angles, had greater leaflet tilt angles, wider limb angles, greater Zn deficiency, less black pecan aphid susceptibility, and less red coloration to foliage than did northern most provenances. Trees originating from Jaumaua, in northern Mexico, were especially noteworthy insomuch that they were by far the tallest, possessed the largest trunk diameters, the longest foliation period, and lowest Zn deficiency ratings of all provenances. One family within this Jaumaua population also exhibited a high level of cold hardiness. Family heritability (hf2) estimates were ≥0.48 for trunk cross sectional area, date of budbreak, leaf redness, cold injury, leaflet droop angle, and leaflet tilt angle, and ≤0.39 for late season leaf fall, black pecan aphid susceptibility, zinc deficiency, and branch angle.
Variability for Restriction Fragment-length Polymorphisms (RFLPs) and Relationships among Elite Commercial Inbred and Virtual Hybrid Onion Populations
Authors: King Joseph J. , Bradeen James M. , Havey Michael J.
Published: January 2019

Nuclear RFLPs were used to estimate relationships among 14 elite commercial inbreds of bulb onion (Allium cepa) from Holland, Japan, and the United States. Variability for known alleles at 75 RFLP loci and 194 polymorphic fragments revealed by 69 anonymous cDNA probes and a clone of alliinase were scored to yield genetically characterized and uncharacterized data sets, respectively. The inbred onion populations possessed more than two alleles at 20 of 43 (46%) codominant RFLP loci. Relationships among the inbreds were estimated by cluster analysis of simple-matching (genetically characterized data) and Jaccard (genetically uncharacterized data) coefficients using the unweighted pair group method and agreed with known pedigrees. RFLPs confidently distinguished among elite inbreds within and between specific market classes. RFLP profiles for virtual hybrids were computer-generated by combining gametic arrays among inbreds of the same market class and analyzed as described above. Allelic and genetically uncharacterized RFLPs confidently distinguished among these hybrids, even though heterozygosity for many markers produced a majority of monomorphic fragments. We randomly sampled decreasing numbers of RFLPs from the complete data sets and calculated simple-matching and Jaccard distances, noting the numbers of probes that were unable to distinguish any two inbreds or hybrids. As few as 10 polymorphic probe-enzyme combinations distinguished among all the inbreds and samples of 20 genetically characterized or 10 genetically uncharacterized clones distinguished all the virtual hybrids. This study demonstrated that the previously reported few RFLPs observed among open-pollinated (OP) onion populations were due to the highly heterozygous nature of the OP population.
Interaction between Colletotrichum lindemuthianum Races and Gene Pool Diversity in Phaseolus vulgaris
Authors: Balardin R.S. , Kelly J.D.
Published: January 2019

Sixty-two genetically diverse modern and traditional Phaseolus vulgaris L. cultivars from Brazil, the Dominican Republic, Honduras, Mexico, the Netherlands, and the United States, representative of the Andean and Middle American gene pools, were selected to study the interaction with distinct races of Colletotrichum lindemuthianum (Sacc. & Magnus) Lams.-Scrib. Principal component and phenetic analyses were conducted on the disease reaction to inoculation with 34 races of C. lindemuthianum from Argentina, Brazil, Colombia, Costa Rica, the Dominican Republic, Honduras, Mexico, Peru, and the United States. The principal component analysis revealed four clusters in which only one cluster consisted of cultivars from both gene pools. Bean genotypes clustered based on the gene pool origin of the resistance genes present, regardless of the actual gene pool of the host genotype. Middle American genotypes in cluster A carried Andean resistance genes. Further grouping of genotypes based on overall level of resistance within each gene pool was observed. Clusters A and C consisted of the most resistant genotypes from both gene pools. The distribution of genotypes generated by the phenetic analysis, placed the most resistant and susceptible genotypes of the anthracnose differential series at the extremities of the phenogram, providing support for the range in genotypic resistance exhibited by members of the differential series. Races of C. lindemuthianum isolated from Middle American genotypes showed broad virulence on germplasm from both gene pools, whereas races with Andean reaction showed high virulence only on Andean germplasm. The reduced virulence of Andean races on Middle American genotypes suggests selection of virulence factors congruent with diversity in P. vulgaris. In addition, races of C. lindemuthianum formed two clusters corresponding to the Middle American and Andean reaction groups based on the phenetic analysis. In the principal component analysis, most races with the Andean reaction were observed in the clusters C and D, except races 15 and 23 which clustered with Middle American races in cluster B. Only races 38, 39 and 47 from the Dominican Republic showed high similarity in both multivariate analyses and clustered based on geographic origin. Races from other countries showed no geographic effect. The overlapping of specific races, however, with races from different reaction groups might indicate that this group of isolates possesses factors of virulence to both host gene pools. Data based on virulence supports variability in C. lindemuthianum structured with diversity in P. vulgaris.
Alternate Bearing in Pistachio as a Masting Phenomenon: Construction Cost of Reproduction versus Vegetative Growth and Storage
Authors: Stevenson M.T. , Shackel K.A.
Published: January 2019

Whole-tree effects of alternate bearing on the reproductive growth, vegetative growth, and carbohydrate storage in mature pistachio (scion Pistacia vera L., rootstock Pistacia atlantica Desf.) were examined. Although it is generally accepted that the “off” year in pistachio may be used to accumulate carbohydrate reserves, it was found that starch and sugars from the “off” year equaled only 8% of the construction cost of the “on” year's fruit load. The dry mass increase in perennial woody tissue of roots, trunk and branches in the “off” year (20.2 kg/tree), was 75% of the mass of fruit in “on” trees (26.4 kg/tree). When construction cost of wood and fruit is considered, “off” year woody tissue growth is 64% of “on” year fruit growth. Since previous studies have shown that leaf dry mass is generally 30% greater in “off” than “on” pistachio trees, we conclude that the overall production of biomass in “off” and “on” year pistachio is similar. Therefore, we suggest that the “off” year is not a period of substantial storage carbohydrate accumulation, but rather a switch in allocation from reproductive to vegetative growth. This is consistent with ecologically based theories of the adaptive advantage of masting behavior, and suggests that withholding water and fertilizer during the “off” year may not harm “on” year yield.
Environmental Influences on Photosynthesis and Carbon Export in Greenhouse Roses during Development of the Flowering Shoot
Authors: Jiao Jirong , Grodzinski Bernard
Published: January 2019

Photosynthesis and concurrent export rates of expanded leaves on the flowering shoot of Rosa hybrida L. `Samantha' were measured at three stages of shoot and flower bud development. At 35 and 90 Pa CO2 photosynthesis and concurrent export rates of the upper expanded leaves were greater at Stage 3 (i.e., when petal color of the flower bud was visible) than at the two earlier stages of shoot and flower development. The optimum for leaf photosynthesis and concurrent export at ambient CO2 and saturating irradiance were ≈25 °C. Export was more sensitive to increased temperature than was carbon fixation. For example, at 40 °C photosynthesis was 40% lower while the export rate during photosynthesis was reduced by 80%. Increasing the photon fluence flux rate from 200 to 1000 μmol·m-2·s-1 PAR increased the photosynthetic rate and the concurrent export rate at 35 and 90 Pa CO2, but the increase in export was proportionally greater than that of photosynthesis. At 35 Pa CO2, the rate of C export during photosynthesis increased from 31 to 59% of the concurrent C fixation rate. At 90 Pa CO2, export during photosynthesis increased from 38 to 62% of the photosynthesis rate. The importance of irradiance on translocation processes was further demonstrated by comparing the disappearance of label during the feed period and during an extended night period. Plants grown at each CO2 level exported about three times as much of the 14C fixed during a 2-hour feed period in the light as during a subsequent 15-hour dark chase period. The nighttime export and respiration rates of leaves which had been exposed to elevated CO2 levels during the feed were higher than those rates observed at ambient CO2. However, at the end of the chase period, the leaves of plants which had been exposed to CO2 enrichment during the feed also retained more 14C than did the leaves of the plants which were at ambient CO2. Thus, although more 14C was fixed and exported under high CO2, the same proportion of labelled assimilates were exported, respired, and retained in the dark as at ambient CO2.
Aroma Volatile Profiles from Ripe Tomatoes are Influenced by Physiological Maturity at Harvest: An Application for Electronic Nose Technology
Authors: Maul Fernando , Sargent Steven A. , Balaban Murat O. , Baldwin Elizabeth A. , Huber Donald J. , Sims Charles A.
Published: January 2019

The effect of physiological maturity at harvest on ripe tomato (Lycopersicon esculentum Mill.) volatile profiles was studied using ripening response time (in days) to 100 μL·L-1 exogenous ethylene treatment as a tool to separate immature-green from mature-green fruit. Electronic nose (EN) sensor array and gas chromatography (GC) analyses were used to document volatile profile changes in tomatoes that required a 1-, 3-, or 5-day ethylene treatment to reach the breaker stage. EN output analysis using multivariate discriminant and canonical analyses classified intact tomato and whole tomato homogenate samples that required 3 or 5 days of ethylene treatment as significantly different (P < 0.01) from those that required only 1 day. The GC aroma profiles from whole tomato homogenate showed that 1-day fruit had significantly higher levels (P < 0.05) of 1-penten-3-one, cis-3-hexenal, 6-methyl-5-hepten-2-one, 2-isobutylthiazole, and geranylacetone when compared to 5-day fruit. Analysis of excised tomato tissues showed that pericarp (including columnella) produced an average 219% greater concentration of the 16 aroma volatiles quantified by GC when compared to locular gel (442 and 203 μL·L-1, respectively). EN analysis concurred with GC by showing greater average Mahalanobis distance between pericarp tissue groupings when compared to locular gel groupings (78.25 and 12.33 units, respectively). Pericarp tissue from the 5-day ethylene treatment showed significantly lower levels of 1-penten-3-one, trans-2-heptenal, 6-methyl-5-hepten-2-one, 2-isobutylthiazole, geranylacetone, and β-ionone compared to the 1- and 3-day treatments, Similarly, locular gel from the 3- and 5-day ethylene treatments had significantly lower levels of 1-penten-3-one, 2-isobutylthiazole, and 1-nitro-2-phenylethane compared to 1-day samples. cis-3-Hexenol in locular gel was the only volatile compound that showed significantly higher levels with increasing ethylene treatment. EN analysis showed greater Mahalanobis distances between 1- and 3-day ethylene samples than between 3- and 5-day ethylene samples (32.09 and 12.90, 24.14 and 6.52, 116.31 and 65.04, and 15.74 and 13.28 units, for intact tomato, whole tomato, pericarp, and locular gel homogenate, respectively).
Optimizing the Calcium Content of a Copolymer Acrylamide Gel Matrix for Dark-grown Seedlings
Authors: Myers Patricia Newton , Mitchell Cary A.
Published: January 2019

A copolymer acrylamide acrylate gel was investigated as the sole root matrix for dark-grown seedlings of soybean (Glycine max Merr. `Century 84'). Increasing Ca2+ in the hydrating solution of the hydrogel from 1 to 10 mm decreased its water-holding capacity from 97 to 46 mL·g-1, yet water potential of the medium remained high, sufficient for normal plant growth at all Ca2+ concentrations tested. Elongation rate of dark-grown soybean seedlings over a 54-hour period was 0.9, 1.5, and 1.8 mm·h-1 with 1.0, 2.5, or 5.0 mm Ca2+, respectively, but did not increase with further increases in Ca2+ concentration. Further study revealed that Na+ was released from the hydrogel medium and was taken up by the seedlings as Ca2+ increased in the medium. In dry hypocotyl tissue, sodium content correlated negatively with calcium content. Despite the presence of Na+ in the hydrogel, seedling growth was normal when adequate Ca2+ was added in the hydrating solution. Acrylamide hydrogels hold good potential as a sole growth matrix for short-term experiments with dark-grown seedlings without irrigation.
Changes in Polyamine Levels in Relationship to the Double-sigmoidal Growth Curve of Peaches
Authors: Kushad Mosbah M.
Published: January 2019

Polyamines and the activities of their biosynthetic enzymes were evaluated during peach (Prunus persica L. `Biscoe') mesocarp (pulp) and seed growth starting at full bloom and until full fruit maturity at 14 weeks after full bloom (AFB). Mesocarp fresh mass exhibited a double-sigmoidal pattern characteristic of peaches. Seed fresh mass increased to a maximum of≈1 g at 4 weeks AFB then remained unchanged during the remaining weeks of sampling. Free putrescine, spermidine, and spermine levels were significantly higher in the flower bud, declined in the mesocarp tissue during the first 2 weeks AFB, then exhibited another increase between 2 and 6 weeks AFB. In contrast, conjugated spermidine and spermine levels were low in flower buds, then increased to their maximum level at 6 weeks AFB, then declined at full fruit development. Ornithine decarboxylase (ODC, EC 4.1.1.17) activity was high in flower buds (89.3 nmol·h-1·mg-1 protein) and in early stages of mesocarp development then declined to its lowest level (5.8 nmol·h-1·mg-1 protein) at full-fruit development. Arginine decarboxylase (ADC, 4.1.1.19) activity did not change during the first 6 weeks of mesocarp growth but declined later, reaching its lowest (1.95 nmol·h-1·mg-1 protein) at 14 weeks AFB. During the first 5 weeks AFB, ODC activity was 3.0- to 4.5-fold that of ADC activity; however, at full-fruit maturity (14 weeks AFB) the activities of both enzymes were similar. The slowdown in mesocarp growth during pit hardening between 6 and 9 weeks AFB did not change polyamines concentrations or their biosynthetic enzymes. Free spermidine and spermine levels declined during seed development; however, between 7 and 9 weeks AFB an increase in putrescine was observed. Similarly, conjugated putrescine increased substantially during seed growth reaching its highest level of 680 nmol·g-1 fresh mass at week 8 then declined at the later weeks, while conjugated spermidine and spermine peaked at week 10 to 1,169 and 2,148 nmol·g-1 fresh mass. ODC and ADC activities declined between 3 and 5 weeks AFB. However, a significant increase in ADC but not ODC activity in the seed tissue was observed during pit hardening between 6 and 10 weeks AFB. Based on the rapid increase in putrescine and ADC activity in the seed tissue, it appears that pit hardening may be a stress-related phenomenon. Data also suggest that polyamine levels in the mesocarp and seed tissue are independently regulated.
Methionine-Riboflavin Mixtures with Surfactants and Metal Ions Reduce Powdery Mildew Infection in Strawberry Plants
Authors: Wang Shiow Y. , Tzeng Dean Der-Syh
Published: January 2019

Foliar application of a mixture of methionine (1 mm) and riboflavin (26.6 μm) reduced the severity of powdery mildew [Sphaerotheca macularia (Wallr. ex Fr.) Jacz. f. sp. fragariae] infection in `Earliglow' strawberry (Fragaria × ananassa Duch.) plants. Efficacy of this mixture on controlling powdery mildew infection was enhanced by supplements of copper, iron, and surfactants [sodium dodecyl sulfate (SDS), Triton X-100, Tween-20, or oxyalkylenemethylsiloxane (Silwet L-77)]. Free-radical scavengers (n-propyl gallate, thiourea) and antioxidants (α-tocopherol, β-carotene) reduced the efficacy of this mixture. Plants treated with a mixture of riboflavin (26.6 μm), d,l-methionine (1 mm), copper sulfate pentahydrate (1 mm), and surfactants (SDS or Silwet L-77 at concentrations of 0.05% to 0.1%) showed a decrease in powdery mildew infection. Results of this study suggest that treatment with a mixture of methionine and riboflavin is beneficial to strawberry plants and may serve as an alternative to fungicides for controlling powdery mildew.
Inheritance of Phytophthora Root Rot and Foliar Blight Resistance in Pepper
Authors: Walker Stephanie J. , Bosland Paul W.
Published: January 2019

The inheritance of resistance to Phytophthora capsici Leonian root rot and foliar blight was compared in two different Capsicum annuum L. var. annuum pod types. The seedling was screened for phytophthora root rot, while a genetically identical stem cutting was screened for phytophthora foliar blight to determine if the same gene(s) confer resistance to both disease syndromes. The susceptible parents were `Keystone Resistant Giant #3' (`Keystone'), a bell pepper type, and `Early Jalapeño', while `Criollo de Morelos-334' was the resistant parent. Resistance was observed in both F1 populations screened for phytophthora root and foliar infection indicating dominance for resistance. Reciprocal effects were not detected. To determine if the same gene(s) conferred root rot and foliar resistance, root rot screening results were matched to the corresponding foliar blight stem cutting reaction. The segregation of resistance in the F2 generations was dependent on the susceptible parent. In the F2 generation derived from `Early Jalapeño', root rot resistance and foliar blight resistance segregated in a 9:3:3:1 (root resistant/foliar resistant: root resistant/foliar susceptible: root susceptible/foliar resistant: root susceptible/foliar susceptible) ratio. One independent, dominant gene was necessary for root rot resistance, and a different independent, dominant gene was needed for foliar blight resistance. In the F2 generation derived from `Keystone', root rot and foliar blight resistance segregated in a 7:2:2:5 (root resistant/foliar resistant: root resistant/foliar susceptible: root susceptible/foliar resistant: root susceptible/foliar susceptible) ratio. This segregation ratio is expected when one dominant gene is required for root resistance, and a different dominant gene is required for foliar resistance. In addition to these two genes, at least one dominant allele of a third gene must be present for expression of root rot and foliar blight resistance.
Alcohol Dehydrogenase Expression and Alcohol Production during Pear Ripening
Authors: Chervin Christian , Truett Janyce K. , Speirs Jim
Published: January 2019

Regulation of alcohol dehydrogenase (ADH), activity of pyruvate decarboxylase (PDC) and accumulation of acetaldehyde and ethanol in `Packham's Triumph' pears (Pyrus communis, L.) subsequent to different storage regimes were investigated. Pears were stored for two months at -1 °C either in air (Air) or under hypoxia at 3 kPa O2 (Hyp) and subsequently warmed and allowed to ripen in air at 20 °C. One set of fruit stored in air at -1 °C was subjected to 3 days of hypoxia at -1 °C (Air+Hyp) before ripening in air. Acetaldehyde, ethanol and methanol levels increased in all fruit in a similar fashion during ripening and did not reflect differences in storage treatments. During ripening, ADH activities in posthypoxic samples were generally twice that of air samples. PDC activities increased for ≈6 days during ripening then declined slightly but did not differ significantly among treatments. Upon transfer to 20 °C in air, slightly higher levels of Adh mRNA were observed in samples treated with hypoxia than in air controls. Over the following 2 days at 20 °C, the Adh transcription was markedly induced in Air and Air+Hyp samples. Although all Adh mRNAs returned to control levels within 4 days, ADH activities remained higher in hypoxia-treated fruit than in controls for up to 18 days. These results suggest that, in ripening pears, ADH does not limit ethanol production, and that the expression of this enzyme comprises post-transcriptional regulations. GenBank accession numbers of the Adh cDNAs are AFO 31899 and AFO 31900.
Ethylene Biosynthesis and Polyamine and ABA Levels in Cut Carnations Treated with Aminotriazole
Authors: Serrano María , Martínez-Madrid Ma Concepción , Romojaro Félix
Published: January 2019

Treatment of cut `Master' carnations (Dianthus caryophyllus L.) with 50 mm aminotriazole (ATA) in distilled water for 5 days retarded senescence, increased flower longevity by 4 days compared to the control carnations kept in distilled water and inhibited the climacteric peak of ethylene production normally produced during the senescence of these flowers. The treatment had no effect, however, on the levels of the polyamines putrescine and spermidine. Thus, the biosynthetic routes of ethylene and polyamines may not compete for the common precursor S-adenosylmethionine (SAM). Also, in the petals of the control carnations, increased ethylene production was correlated with increased ion leakage and abscisic acid (ABA) levels. In the ATA treated petals, ion leakage and ABA levels increased later and reached values less than 50% compared to the control carnations. Chemical names used: abscisic acid (ABA), 3-1H-amino-1,2,4-triazole-1-yl (aminotriazole), 1-aminocyclopropane-1-carboxylic acid (ACC), S-adenosyl methionine (SAM).
In vitro Assay Selection of Glyphosate Resistance in Lettuce
Authors: Torres Antonio C. , Nagata Russell T. , Ferl Robert J. , Bewick Thomas A. , Cantliffe Daniel J.
Published: January 2019

Glyphosate-resistant plants of `South Bay' lettuce (Lactuca sativa L.) were produced by using Agrobacterium tumefaciens containing a plasmid carrying glyphosate oxidase and EPSPS gene. An in vitro assay was performed to determine the sensitivity of `South Bay' leaf discs and seedling explants to varying glyphosate concentrations. The I50 for glyphosate leaf discs was 53.8 μm and for glyphosate seedlings 7.6 μm. There was a high correlation between the response of leaf discs and seedlings to glyphosate based on dry weight. These findings will allow identification of glyphosate-resistant transformants in an early stage of plant development, saving time and reducing the cost in generating an improved cultivar with the glyphosate resistance trait.
Crape Myrtle Post-transplant Growth as Affected by Nitrogen Nutrition during Nursery Production
Authors: Cabrera Raul I. , Devereaux Diana R.
Published: January 2019

Containerized crape myrtle (Lagerstroemia indica L. × Lagerstroemia fauriei Koehne `Tonto') plants were grown for 9 months under various nitrogen fertility regimes, and then transplanted to a sandy loam soil with minimal management to evaluate their landscape establishment and growth performance. During the nursery phase plants were irrigated, except over an overwintering period, with complete nutrient solutions differing in applied N concentration, ranging from 15 to 300 mg·L-1. By 16 weeks after transplanting (WAT) into the landscape soil, plant biomass was significantly higher in the plants that had been grown with higher N supplies and had been among the smallest at transplant. Such plant growth response was linearly and positively correlated to plant N status at transplant. Plant shoot to root ratio and tissue N, Ca, S, and Fe concentrations, which had been significantly affected by the N fertilization regime in the nursery, equalized over time after transplant, with no significant differences observed among treatments by 16 WAT. Flowering response in the landscape was delayed in plants originally grown with the higher N supplies. Plant survival and establishment per se were not affected by treatments; no plants were lost, and aside from the differences in size and flower timing, all plants were considered aesthetically similar.
Efficiency of Randomly Amplified Polymorphic DNA to Sequence Characterized Amplified Region Marker Conversion and their Comparative Polymerase Chain Reaction Sensitivity in Cucumber
Authors: Horejsi Thomas , Box Jodie M. , Staub Jack E.
Published: January 2019

The conversion of randomly amplified polymorphic DNA (RAPD) markers to sequence characterized amplified region (SCAR) markers, and the effects of differing polymerase chain reaction (PCR) conditions were studied in cucumber (Cucumis sativus L.). Attempts were made to clone and sequence 75 RAPD PCR products to produce SCAR primers (16 to 22 nucleotides) designed to amplify original RAPD PCR products. The influence of template DNA source, purity, and concentration, MgCl2 concentration, Taq polymerase source, and type of thermocycler upon RAPD and SCAR marker performance was evaluated. Conversion of RAPD to SCAR markers was not universally successful, and SCAR primers reacted differently to varying PCR conditions. Only 48 (64%) of 75 RAPD markers were successfully converted to SCAR markers and 11 (15%) of these reproduced the polymorphism observed with the original RAPD PCR product. Moreover, some SCAR primer pairs produced multiple polymorphic PCR products. The band intensity of SCAR markers were brighter (P = 0.05) than their corresponding RAPD markers with only one exception. The SCAR markers examined were less influenced (P = 0.05) by MgCl2 concentration than their corresponding RAPD markers. However, some SCAR markers were more sensitive to reaction impurities than their RAPD counterparts and SCAR markers tended to be less readily visualized (decrease in frequency of visible PCR product) with low concentrations (1 and 2 mm) of template DNA than their corresponding RAPD markers. Neither the source of Taq nor the type of thermocycler used affected the performance of SCAR and RAPD markers. These data suggest that although SCAR markers may demonstrate enhanced performance over the RAPD markers from which they are derived, careful consideration must be given to both the costs and potential benefits of SCAR marker development in cucumber.
Cloning cDNAs for Genes Preferentially Expressed during Fruit Growth in Cucumber
Authors: Suyama Takuro , Yamada Kunio , Mori Hitoshi , Takeno Kiyotoshi , Yamaki Shohei
Published: January 2019

A cDNA library was constructed from poly(A)+RNA extracted from pollinated fruit of `PMR-142' cucumber (Cucumis sativus L.). Subtraction hybridization was made between the cDNAs and poly(A)+RNA from unpollinated fruit to isolate cDNA clones that corresponded to the genes preferentially expressed in the pollinated fruit. We isolated three cDNAs, which were 756, 826, and 998 nucleotides long and designated Csf1, Csf2, and Csf3, respectively. When fruit growth was triggered by pollination, auxin treatment and natural parthenocarpy, Csf2 was always expressed. Time course of expression of the Csf2 gene was nearly parallel to that of the fruit growth. Nucleotide sequences of the Csf cDNAs were fully determined. Homology of the deduced amino acid sequence for Csf1 showed 75% identity with a pea extensin. Only 37%, 33%, and 26% homology was found between Csf2 and bell pepper CaSn-2, tobacco FB7-4, and opium poppy gMLP15, respectively. The Csf3 sequence showed 68% identity with the large subunit of 60S ribosomal protein L3 of Arabidopsis thaliana.
Maturity and Regional Influences on Watercore Development and its Postharvest Disappearance in `Fuji' Apples
Authors: Harker F. Roger , Watkins Christopher B. , Brookfield Paul L. , Miller Mellisa J. , Reid Suzanne , Jackson Phillippa J. , Bieleski Roderick L. , Bartley Tim
Published: January 2019

Preharvest development and postharvest disappearance of watercore in `Fuji' apples (Malus ×domestica Borkh.) from a northern (Hawke's Bay, latitude 39° south) and southern (Otago, latitude 45° south) region of New Zealand were compared. A new method for quantifying watercore was developed. A photocopy was taken of the symptoms after each fruit was cut in half through the equator, and then the area of affected flesh (photocopies black) was measured using morphometric methods and compared to the area of unaffected flesh (photocopies white). Watercore was more severe and developed earlier in the season in Otago than in Hawke's Bay. In Otago, a block-type watercore predominated, disorder symptoms initially appearing in the tissues located at the junction of two carpels, while in Hawke's Bay a radial-type of watercore predominated, initially appearing in the tissues surrounding the coreline vascular bundles. Regression analysis identified that orchard and harvest date accounted for most of the differences in watercore symptoms and that the initial appearance of low levels of watercore was the best predictor that fruit would start to develop commercially significant levels of watercore. Incorporation of background color, internal ethylene concentration, starch pattern index, and firmness only slightly improved the regression coefficient. Watercore disappeared from the flesh during storage of fruit from both regions. Fruit from early harvests had the least severe symptoms, and the highest rates of watercore disappearance during storage. In fruit with more severe symptoms at harvest, its disappearance during storage was associated with an increase in fruit volume and air space, which occurred despite continuing mass loss. We suggest that during storage, the extracellular fluid associated with watercore symptoms is absorbed into the cells, and thus drives the increase in fruit volume.
Water Stress and Crop Level Interactions in Relation to Nectarine Yield, Fruit Size Distribution, and Water Potentials
Authors: Naor A. , Klein I. , Hupert H. , Grinblat Y. , Peres M. , Kaufman A.
Published: January 2019

The interactions between irrigation and crop level with respect to fruit size distribution and soil and stem water potentials were investigated in a nectarine (Prunus persica (L.) Batsch. `Fairlane') orchard located in a semiarid zone. Irrigation treatments during stage III of fruit growth ranged from 0.62 to 1.29 of potential evapotranspiration (ETp). Fruit were hand thinned to a wide range of fruit levels (200 to 1200 fruit/tree in the 555-tree/ha orchard). Total yield did not increase with increasing irrigation rate above 0.92 ETp in 1996 and maximum yield was found at 1.06 ETp in 1997. Fruit size distribution was shifted towards larger fruit with increasing irrigation level and with decreasing crop level. The two highest irrigation treatments had similar midday stem water potentials. Our findings indicate that highest yields and highest water use efficiency (yield/water consumption) are not always related to minimum water stress. Total yield and large fruit yield were highly and better correlated with midday stem water potential than with soil water potential. This confirms other reports that midday stem water potential is an accurate indicator of tree water stress and may have utility in irrigation scheduling.
Potassium Requirements for Maximum Yield and Fruit Quality of Processing Tomato
Authors: Hartz T.K. , Miyao G. , Mullen R.J. , Cahn M.D. , Valencia J. , Brittan K.L.
Published: January 2019

A survey of 140 processing tomato (Lycopersicon esculentum Mill.) fields in central California was conducted in 1996-97 to examine the relationship between K nutrition and fruit quality for processing. Quality parameters evaluated were soluble solids (SS), pH, color of a blended juice sample, and the percent of fruit affected by the color disorders yellow shoulder (YS) or internal white tissue (IWT). Juice color and pH were not correlated with soil K availability or plant K status. SS was correlated with both soil exchangeable K and midseason leaf K concentration (r = 0.25 and 0.28, p < 0.01) but the regression relationships suggested that the impact of soil or plant K status on fruit SS was minor. YS and IWT incidence, which varied among fields from 0% to 68% of fruit affected, was negatively correlated with K status of both soil and plant. Soil exchangeable K/√Mg ratio was the measure of soil K availability most closely correlated with percent total color disorders (YS + IWT, r = -0.45, p < 0.01). In field trials conducted to document the relationship between soil K availability and the fruit color disorders, soil application of either K or gypsum (CaSO4, to increase K/√Mg ratio) reduced YS and total color disorders. Multiple foliar K applications were effective in reducing fruit color disorders at only one of two sites. In no field trial did K application improve yield, SS, or juice color.
Molecular Typing of S-alleles through Identification, Characterization and cDNA Cloning for S-RNases in Sweet Cherry
Authors: Tao Ryutaro , Yamane Hisayo , Sugiura Akira , Murayama Hideki , Sassa Hidenori , Mori Hitoshi
Published: January 2019

This report identifies S-RNases of sweet cherry (Prunus avium L.) and presents information about cDNA sequences encoding the S-RNases, which leads to the development of a molecular typing system for S-alleles in this fruit tree species. Stylar proteins of sweet cherry were surveyed by two dimensional polyaclylamide gel electrophoresis (2D-PAGE) to identify S-proteins associated with gametophytic self-incompatibility. Glycoprotein spots linked to S-alleles were found in a group of proteins which had Mr and pI similar to those of other rosaceous S-RNases. These glycoproteins were present at highest concentration in the upper segment of the mature style and shared immunological characteristics and N-terminal sequences with those of S-RNases of other plant species. cDNAs encoding these glycoproteins were cloned based on the N-terminal sequences. Genomic DNA and RNA blot analyses and deduced amino acid sequences indicated that the cDNAs encode S-RNases; thus the S-proteins identified by 2D-PAGE are S-RNases. Although S1 to S6-alleles of sweet cherry cultivars could be distinguished from each other with the genomic DNA blot analysis, a much simpler method of PCR-based typing system was developed for the six S-alleles based on the DNA sequence data obtained from the cDNAs encoding S-RNases.
Auxin Applications Affect Posttransplant CO2 Exchange Rate and Growth of Bare-rooted Vinca [Catharanthus roseus (L.) G. Don] Seedlings
Authors: van Iersel Marc
Published: January 2019

Uprooting and transplanting seedlings can cause root damage, which may reduce water and nutrient uptake. Initiation of new roots and rapid elongation of existing roots may help minimize the negative effects of transplant shock. In this study, seedlings with four true leaves were transplanted into diatomaceous earth and the plants were transferred to a growth chamber, where they were treated with NAA (0, 0.025, 0.25, and 2.5 mg·L-1; 36 mL/plant). The effects of drenches with various amounts of 1-naphthaleneacetic acid (NAA) on the posttransplant CO2 exchange rate of vinca [Catharanthus roseus (L.) G. Don] were quantified. Whole-plant CO2 exchange rate of the plants was measured once every 20 minutes for a 28 day period. Seedlings treated with 0.025 or 0.25 mg·L-1 recovered from transplant shock more quickly than plants in the 0 and 2.5 mg·L-1 treatments. Naphthaleneacetic acid drenches containing 0.025 or 0.25 mg·L-1 increased whole-plant net photosynthesis (Pnet) from 10 days, dark respiration (Rdark) from 12 days, and carbon use efficiency (CUE) from 11 days after transplanting until the end of the experiment. The increase in CUE seems to have been the result of the larger size of the plants in these two treatments, and thus an indirect effect of the NAA applications. These differences in CO2 metabolism among the treatments resulted in a 46% dry mass increase in the 0.025 mg·L-1 treatment compared to the control, but shoot-root ratio was not affected. The highest rate of NAA (2.5 mg·L-1) was slightly phytotoxic and reduced the growth rate of the plants.