bluuebunny/crossref_metadata_2025 huggingface dataset:
Light Effects on Wax Begonia: Photosynthesis, Growth Respiration, Maintenance Respiration, and Carbon Use Efficiency
Authors: Nemali Krishna S. , van Iersel M.W.
Published: January 2019

The effect of increasing daily light integral (DLI; 5.3, 9.5, 14.4, and 19.4 mol·m-2·d-1) on photosynthesis and respiration of wax begonia (Begonia semperflorens-cultorum Hort.) was examined by measuring CO2 exchange rates (CER) for a period of 25 d in a whole-plant gas exchange system. Although plant growth rate (GR, increase in dry weight per day) increased linearly with increasing DLI, plants grown at low DLI (5.3 or 9.5 mol·m-2·d-1) respired more carbohydrates than were fixed in photosynthesis during the early growth period (13 and 4 d, respectively), resulting in a negative daily carbon gain (DCG) and GR. Carbon use efficiency [CUE, the ratio of carbon incorporated into the plant to C fixed in gross photosynthesis (Pg)] of plants grown at low DLI was low, since these plants used most of the C fixed in Pg for maintenance respiration (Rm), leaving few, if any, C for growth and growth respiration (Rg). Maintenance respiration accounted for a smaller fraction of the total respiration with increasing DLI. In addition, the importance of Rm in the carbon balance of the plants decreased over time, resulting in an increase in CUE. At harvest, crop dry weight (DWCROP) increased linearly with increasing DLI, due to the increased photosynthesis and CUE at high PPF.
Relationship between Understory Light and Growth of Forest-grown American Ginseng (Panax quinquefolius L.)
Authors: Fournier Anick R. , Gosselin André , Proctor John T.A. , Gauthier Louis , Khanizadeh Shahrokh , Dorais Martine
Published: January 2019

Our objective was to determine the relationship between daily and seasonal changes in understory light, and growth of 1- and 2-year-old american ginseng plants cultivated in a broadleaf forest. Using hemispherical photography and spectroradiometry, understory light [total, direct, and diffuse photon flux density (PFD), and sunfleck durations] and light quality [ultraviolet (UV) and red to far red (R:FR)] were evaluated during two consecutive growing seasons. While shoot and root dry weight (DW), and taproot area of 1-year-old american ginseng plants were related to sunfleck durations, accounting for up to 56% of the variation, the relationship reached a plateau at 2 h·d-1 sunfleck durations for growth. In September, growth of 1- and 2-year-old plants exposed to <2 h·d-1 sunfleck durations was positively related to diffuse PFD (and total PFD for 1-year-old plants), accounting for up to 69% of the variation. In mid-season (July 2000), shoot and root growth, and leaflet area of 2-year-old american ginseng were correlated with light PFD and light quality (UV and R:FR), accounting for up to 88% of the variation. Generally, the results suggest that exposing 1- and 2-year-old american ginseng plants to higher diffuse PFD and <2 h·d-1 sunfleck durations increases yield.
Inbreeding, Coancestry, and Founding Clones of Sweet Cherries from North America
Authors: Choi Cheol , Kappel Frank
Published: January 2019

Inbreeding and coancestry coefficients were calculated for 66 sweet cherry (Prunus avium L.) selections released from four breeding programs in North America (HRIO, Vineland, Ont., IAREC, Prosser, Wash., NYSAES, Geneva, N.Y., and PARC, Summerland, B.C.). Highly used founding clones were `Black Heart', `Emperor Francis', `Empress Eugenie', `Napoleon' and `Windsor'. Coefficients of coancestry between all selections and these clones averaged 0.038, 0.045, 0.060, 0.091, and 0.033, respectively. In these five founding clones, coefficients of coancestry in self-compatible selections were over twice as much as those in self-incompatible selections except `Windsor'. In the analysis of coefficients of coancestry between self-incompatible and self-compatible sweet cherry, almost 20% of self-incompatible selections represent more than a half-sib relationship (0.125) to self-compatibles. Increasing and maintaining genetic diversity is needed in sweet cherry breeding program in North America for continued breeding progress.
Inheritance of Normal Pod Development in Bean Golden Yellow Mosaic Resistant Common Bean
Authors: Román Maricelis Acevedo , Castañeda Albeiro Molina , Sánchez Juan Carlos Angel , Muñoz Carlos Germán , Beaver James S.
Published: January 2019

The inheritance of resistance to bean golden yellow mosaic virus (BGYMV) was studied in common beans (Phaseolus vulgaris L.). The original cross was made between breeding line PR9556-158, which produces deformed pods when infected with BGYMV, and PR9556-171, which has normal pod development when inoculated with the virus. Pod type was evaluated on plants from six generations (parental lines, F1, F2, F2:3, F3:4, and backcrosses of the F1 to both parents) at mid-pod fill (R8), ≈65 days after planting. The segregation patterns from the F2, F2:3, F3:4, and backcross populations were consistent with the hypothesis that a single dominant gene confers normal pod development in PR9556-171. When inoculated with BGYMV, the deformed pods of PR9556-158 produced fewer seeds per pod than PR9556-171, resulting in lower seed yield. The gene symbol Bgp-1 has been assigned for this dominant resistance gene that controls the normal pod reaction to BGYMV in common bean.
Effect of Pretreatment of Intact `Gala' Apple with Ethanol Vapor, Heat, or 1-Methylcyclopropene on Quality and Shelf Life of Fresh-cut Slices
Authors: Bai Jinhe , Baldwin Elizabeth A. , Fortuny Robert C. Soliva , Mattheis James P. , Stanley Roger , Perera Conrad , Brecht Jeffrey K.
Published: January 2019

`Gala' apples [Malus silvestris (L.) var. domestica (Borkh.) Mansf.] were treated with ethanol vapor (5 mL·kg-1 fruit for 24 hours at 25 °C), heat (4 days at 38 °C and >98% RH), or 1-methylcyclopropene (1-MCP; 1 or 0.625 μL·L-1 for 18 hours at 20 °C) before processing into slices, then dipped in anti-browning solutions or coatings, drained, and packaged in perforated polyethylene bags. Residual effects of pretreatments on fresh-cut slice physiological and quality attributes were investigated during storage for up to 19 days at 5.5 °C. Ethylene production was reduced by ethanol, heat, and 1-MCP pretreatments, while ethanol and heat also reduced slice respiration. Heat and 1-MCP pretreatments inhibited slice texture changes, while ethanol had no effect on instrumental texture measurements but reduced sensory firmness. Ethanol pretreatment increased the contents of ethanol and ethyl esters in slices but reduced acidity, while heat reduced both acidity and aroma volatile levels. Both ethanol and heat pretreatments led to lower sensory scores for apple flavor and ethanol-pretreated slices also received higher scores for altered flavor, although all scores were in the acceptable range. Slice acidity was best maintained by 1-MCP pretreatment. Shelf life based on appearance was 15 to 16 days for ethanol-pretreated slices and 12 days for heat-pretreated slices compared to that of control, which was 8 to 9 days, while 1-MCP pretreatment promoted decay development on the cut surface, which reduced the shelf life to 7 to 8 days. Obvious separations were determined between ethanol- and heat-pretreated slices and untreated control by canonical discriminant analysis of headspace volatile levels determined by GC and electronic nose. Therefore, pretreatments with ethanol and heat are very effective for prolonging visual shelf life at the expense of aroma quality.
Is There a Relation between Changes in Osmolarity of Cherry Fruit Flesh or Skin and Fruit Cracking Susceptibility?
Authors: Moing Annick , Renaud Christel , Christmann Hélène , Fouilhaux Lydie , Tauzin Yves , Zanetto Anne , Gaudillère Monique , Laigret Frédéric , Claverie Jacques
Published: January 2019

Rain-induced fruit cracking is a limiting factor for sweet cherry (Prunus avium L.) growers in many production areas. Although many studies have concerned this complex phenomenon, the basic mechanisms involved in fruit cracking remain unclear. We re-examined the relations between osmotic potential and cracking susceptibility in cherry fruit by comparing the osmotic contribution of the major metabolites separately in flesh and skin, in four cultivars (with different levels of susceptibility to cracking) at four stages of development. Several differences were observed between flesh and skin revealing compositional gradients in the fruit tissues. Acidity and malate concentrations were higher in flesh than in skin for all stages. The absolute value of osmotic potential was higher but the contribution of the sum of sugars to osmotic potential was lower in flesh than in skin. As determined using fruit immersion test, `Fermina' and `Regina' were less susceptible to fruit cracking than `Lapins' and `Brooks'. At commercial maturity when fruit susceptibility to cracking was highest, no clear difference appeared between `Brooks' and `Lapins' compared to `Regina' and `Fermina' for flesh or skin osmolarity and for the contribution of the major sugars or organic acids to skin and flesh osmotic potential.
Foliar Urea Application in the Fall Affects Both Nitrogen and Carbon Storage in Young `Concord' Grapevines Grown under a Wide Range of Nitrogen Supply
Authors: Xia Guohai , Cheng Lailiang
Published: January 2019

One-year-old `Concord' grapevines (Vitis labruscana Bailey) were fertigated with 0, 5, 10, 15, or 20 mm N in a modified Hoagland's solution for 8 weeks during summer. Half of the vines fertigated at each N concentration were sprayed with 3% foliar urea twice in late September while the rest served as controls. Four vines from each treatment combination were destructively sampled during dormancy to determine the levels and forms of N and carbohydrates. Nitrogen fertigation during the summer did not significantly alter vine N concentration whereas foliar urea application in the fall significantly increased vine N concentration. In response to foliar urea application, concentrations of both free amino acid-N and protein-N increased, but the ratio of protein-N to free amino acid-N decreased. Arginine was the most abundant amino acid in free amino acids and proteins, and its concentration was linearly correlated with vine N concentration. Concentrations of total nonstructural carbohydrates (TNC) decreased slightly in response to N supply from fertigation. Foliar urea application in the fall significantly decreased TNC concentration at each N fertigation level. Starch, glucose, and fructose decreased in response to foliar urea applications, but sucrose concentration remained unaffected. Approximately 60% of the carbon decrease in TNC caused by foliar urea application was recovered in proteins and free amino acids. We conclude that free amino acids account for a larger proportion of the N in vines sprayed with foliar urea compared with the unsprayed vines, but proteins remain as the main form of N storage. In response to foliar urea application, part of the carbon from TNC is incorporated into proteins and free amino acids, leading to a decrease in the carbon stored in TNC and an increase in the carbon stored in proteins and free amino acids.
Concentration Dependence of `Redchief Delicious' Apple Fruit Softening and Chlorophyll Fluorescence to Repeated Doses of 1-Methylcyclopropene
Authors: Jayanty Sastry S. , Cañoles Mauricio , Beaudry Randolph M.
Published: January 2019

We studied the dose-response of `Redchief Delicious' apple [Malus sylvestris (L) Mill. var. domestica (Borkh.) Mansf.] fruit to repeated (weekly) dosages of 0.0, 0.02, 0.1, and 1.0 μL·L-1 1-methylcyclopropene (1-MCP) by measuring fruit firmness and chlorophyll fluorescence throughout an extended storage period at 0, 5, 10, 15, and 20 °C. The rate of firmness loss for nontreated fruit increased with increasing temperature. 1-MCP applied at concentrations of 0.1 and 1.0 μL·L-1 slowed firmness loss. The 1-MCP dose-response curve for the rate of firmness loss was essentially the same for all five temperatures. A concentration of 1.0 μL·L-1 1-MCP prevented firmness loss at all temperatures for the duration of the study; however, after holding fruit for an additional 7 days at room temperature, the fruit stored at 10 °C softened with increasing storage duration, whereas fruit at stored at higher and lower temperatures did not. The influence of 1-MCP on chlorophyll fluorescence (Fo and Fm) was markedly affected by temperature; Fo increased during storage at higher storage temperatures and this increase was enhanced by 1-MCP. Conversely, Fm decreased during storage and the rate of decline was much greater at the higher storage temperatures; the rate of decline was reduced by 1-MCP, but only at the higher storage temperatures. Photochemical efficiency (Fv/Fm) of nontreated fruit declined with time for all storage temperatures. Treatment with 0.1 and 1.0 μL·L-1 1-MCP only marginally reduced the rate of decline of photochemical efficiency. Sample loss due to decay increased with temperature, but was reduced by 1-MCP at all temperatures.
Sorbitol- and Other Sugar-induced Expressions of the NAD+-dependent Sorbitol Dehydrogenase Gene in Japanese Pear Fruit
Authors: Iida Motoko , Bantog Nancy A. , Yamada Kunio , Shiratake Katsuhiro , Yamaki Shohei
Published: January 2019

The regulation of NAD+-dependent sorbitol dehydrogenase (NAD-SDH, EC 1.1.1.14) by sugar was investigated by using sliced tissues of japanese pear (Pyrus serotina Nakai cv. Kousui) fruit in order to determine its role in the mechanism of sugar accumulation in fruit tissue. The results of the activities and steady-state levels of the protein and mRNA indicate that NAD-SDH in japanese pear fruit is among the sugar-inducible genes. By preincubating the sliced tissues for 16 hours in a medium without sugar, NAD-SDH activity declined and reached a stable level that was maintained for up to 40 hours. The washing procedure also reduced the sugar concentration in the apoplast and cytosol of the sliced tissues to low concentrations and enabled them to be manipulated by exogenous applications of carbohydrate solutions. Incubation of tissues in 50 or 100 mm sorbitol for 8 hours led to enhanced expression of the NAD-SDH gene as determined by increased mRNA and protein levels and enhanced enzyme activity. The presence of 100 mm glucose, sucrose, or mannitol also gave significant stimulation on the levels of activity, protein, and mRNA of NAD-SDH compared with those of control tissues bathed in media in which the osmotic potential had been adjusted to that of the sugar solutions by adding polyethylene glycol. However, fructose was ineffective in stimulating NAD-SDH activities and the level of the protein was not enhanced but the level of mRNA was increased. Therefore, it is suggested that NAD-SDH gene transcription is enhanced by each sugar investigated, and fructose appears to be unique as it also influences NAD-SDH at a post-transcriptional level.
Strawberry GenBank-derived and Genomic Simple Sequence Repeat (SSR) Markers and Their Utility with Strawberry, Blackberry, and Red and Black Raspberry
Authors: Lewers K.S. , Styan S.M.N. , Hokanson S.C. , Bassil N.V.
Published: January 2019

Although simple sequence repeat (SSR) markers have been developed for species in the closely related genera Fragaria L. (strawberry) and Rubus L. (raspberry and blackberry), the number of SSRs available is insufficient for genetic mapping. Our objective was to use and compare multiple approaches for developing additional SSRs for Fragaria and Rubus. The approaches included: the development of SSRs from GenBank sequences from species of varied relatedness to Fragaria and Rubus and identified with two different data-mining methods (BLAST and SSRIT); the evaluation of some previously published SSRs designed from related species; and the development of SSRs from a genomic library made from F. ×ananassa Duschene ex Rozier `Earliglow'. When an SSR was developed from a known gene sequence, the location of the repeat in the gene was determined to evaluate the effect on amplification and polymorphism detection. Cross-generic amplification between closely related Fragaria and Rubus as well as transference from species of varied relatedness to Fragaria and Rubus also was evaluated and indicated limited transference within the subfamily Rosoideae. However, development of SSRs for Fragaria and Rubus from Rosa L. (rose) and Rosaceae genera outside Rosoideae was not efficient enough to be practical for new map development. SSRIT was superior to BLAST for identifying GenBank sequences containing repeats. SSRs developed from repeats found in either the 5′UTR (80% polymorphic) or 3′UTR (85% polymorphic) were most likely to detect polymorphisms, compared with those developed from coding regions (30%). SSRs developed from the genomic library were only slightly superior to GenBank-derived SSRs in their ability to detect polymorphisms.
Identification and Mapping of Markers Linked to the Mi Gene for Root-knot Nematode Resistance in Peach
Authors: Gillen Anne M. , Bliss Fred A.
Published: January 2019

An F2 population from a single F1 plant from the cross of peach [Prunus persica (L.) Batsch] rootstock cultivars Harrow Blood (HB) × Okinawa (Oki) was used to locate the Mi locus, which conditions resistance to Meloidogyne incognita (race 1) (Kofoid and White) Chitwood. These data and comparison of common markers among published genetic linkage maps placed the Mi locus on Prunus L. linkage group 2. Two restriction fragment length polymorphisms (RFLPs) [linked at 4.8 and 6.8 centimorgan (cM), repulsion phase] and one random amplified polymorphic DNA (RAPD) marker (linked at 9.5 cM, coupling phase) were linked to Mi. The RAPD marker was cloned, sequenced, and converted to a polymerase chain reaction (PCR)-based cleaved amplified polymorphic sequence (CAPs) marker. Clones of resistance gene analogs (RGA) developed from Oki were highly polymorphic when used as RFLP probes. The RGA's mapped to four linkage groups but clustered on two of the four linkage groups, providing limited coverage of the genome. Even so, they may be useful as markers for disease resistance genes that occur in other populations. The linkage maps of the HB × Oki F2 population and a peach × almond (Prunus amygdalus Batsch) F2 population were colinear in certain regions, however, a significant number of markers mapped to different linkage groups among the two populations. The locus for the blood-flesh trait (red-violet mesocarp) mapped to the top of linkage group 4.
Morphological and Molecular Variation in a Collection of Eggplants from a Secondary Center of Diversity: Implications for Conservation and Breeding
Authors: Prohens Jaume , Blanca José M. , Nuez Fernando
Published: January 2019

Eggplant (Solanum melongena L.) was introduced by the Arabs into Spain. Since then, many local cultivars have arisen. These materials are grouped in four cultivar groups: “round,” “semi-long,” “long,” and “listada de Gandía.” We studied the morphological and molecular [amplified fragment length polymorphism (AFLP)] diversity of a collection of 28 Spanish traditional cultivars of eggplant. Four eggplant accessions from different origins were used as controls and three scarlet eggplant (Solanum aethiopicum L.) accessions as outgroups. Morphology and AFLP markers showed that S. melongena and S. aethiopicum are separate taxonomic entities, and that, compared to controls, Spanish eggplants are very variable, indicating that the Iberian Peninsula can be regarded as a secondary center of diversity. Morphological differences were found among cultivar groups in traits other than those used for the grouping although, in some cases, accessions from different cultivar groups shared a similar general morphology. Eggplant cultivar groups also showed some genetic differences, which are revealed in the gene diversity statistics (GST = 0.30). Nonetheless, no individual AFLP markers specific and universal to one cultivar group could be found. “Round” cultivars were genetically more diverse than the other cultivar groups. A positive correlation (r = 0.68) was found between morphological and molecular distances. However, correlations between geographical and either morphological or molecular distances were low. Results suggest that evolution of eggplants in Spain has involved frequent hybridizations and a frequent movement and exchange of seeds. Structure of diversity among regions indicates that most of the diversity can be collected in single selected regions. All these results have important implications in eggplant germplasm conservation and breeding.
Sugary enhancer1 Inbreds to Improve the Quality of Sugary1 Hybrids of Sweet Corn
Authors: Ordás Bernardo , Revilla Pedro , Soengas Pilar , Ordás Amando , Malvar Rosa A.
Published: January 2019

The better emergence and seedling vigor of sweet corn (Zea mays L.) hybrids homozygous for the gene sugary1 (su1) make them more suitable for cultivation under European Atlantic conditions (cold, wet spring) than those homozygous for other traits. Elite sweet corn inbreds homozygous for both su1 and sugary enhancer1 (se1) could improve the table quality of su1 hybrids. The su1se1 inbreds for improving su1su1 hybrid performance can be chosen in several ways. The aim of this paper was to identify donors among su1se1 inbreds that might improve the quality of su1 hybrids. Eight su1se1 inbreds were crossed with eight su1 inbreds that were parents of fifteen su1 hybrids. Hybrids and inbreds were cultivated next to one another in two locations in northwestern Spain in 1999 and 2000. Several possible estimators for identifying su1se1 inbred donors with favorable alleles lacking in the su1 hybrid were determined. These estimators included the relative number of favorable alleles present in the donor but absent in the hybrid (μǴ), predicted three-way cross (PTC), minimum upper bound (UBND), net improvement (NI), probability of the net gain of favorable alleles when there is complete dominance (PNGg), probability of the net gain of favorable alleles when there is partial dominance or epistasis (PNGceg), and general combining ability (GCA). μǴ and NI were chosen for improving hybrid table quality. These estimators indicate that table quality and other traits of su1 hybrids can be improved by using germplasm from the su1se1 inbred lines. The best donor of quality for most of the hybrids was the inbred line IL731a.
Genetic Variability and Relationship of Closely Related Spanish Traditional Cultivars of Tomato as Detected by SRAP and SSR Markers
Authors: Ruiz Juan J. , García-Martínez Santiago , Picó Belén , Gao Muquiang , Quiros Carlos F.
Published: January 2019

We studied the genetic variability of some traditional tomato (Lycopersicon esculentum L. Mill.) cultivars of Spain, and established their relationships using both simple sequence repeats (SSR) and sequence related amplified polymorphism (SRAP) markers. These included cultivars from different locations of three main types, Muchamiel, De la pera, and Moruno. Additionally we tested two other local cultivars, `Valenciano' and `Flor de Baladre', plus a small sample of commercial cultivars and a few wild species. Both types of markers resolved the cultivars from different groups, but SSR failed to distinguish some of those classified under the same group. All the De la pera cultivars clustered together by genetic similarity with the SRAP markers. The other traditional cultivars, which are grown in a wider geographic range, formed a more diffuse group, which included the commercial cultivar Roma. The Mexican cultivar Zapotec, a breeding line, and the virus-resistant commercial hybrid `Anastasia' were the most distant of all the cultivars. The latter hybrid had higher similarity to the wild species due to introgressed segments from them carrying the resistance genes. Similar results were observed for SSR markers but with a lower level of resolution. This information would be useful to facilitate tomato germplasm conservation and management efforts.
Developmental Anatomy of Adventitious Shoot Formation on Snapdragon (Antirrhinum majus L.) Hypocotyls In Vitro
Authors: Busse James S. , Figueroa-Cabanas M. , Stimart D.P.
Published: January 2019

Developmental anatomy of adventitious shoot formation in vitro from snapdragon (Antirrhinum majus L.) hypocotyls was investigated using two inbred lines, the most (R) and least (NR) regenerative lines selected from screening (Schroeder and Stimart, 1999). Time course analysis indicated cell division in the most regenerative line occurred first in one or a small number of epidermal cells with periclinal and anticlinal divisions within 2 days of placing hypocotyls on induction medium. Subsequently, cortical then vascular cells were recruited beneath the dividing epidermal cells. Once shoots formed, their vascular system was continuous with the original hypocotyl explant. The least regenerative line had no cell division directed towards organogenesis through 6 days. Shoot formation on snapdragon hypocotyls was adventitious in origin, by direct organogenesis and genotype dependent.
Flavor Precursor [S-alk(en)yl-L-cysteine sulfoxide] Concentration and Composition in Onion Plant Organs and Predictability of Field White Rot Reaction of Onions
Authors: Hovius Marilyn H.Y. , Goldman Irwin L. , Parkin Kirk L.
Published: January 2019

Breeders have found field screening for white rot (Sclerotium cepivorum Berk.) resistance in onion (Allium cepa L.) to be unreliable since consistently moderate to high disease levels that significantly differentiate cultivars do not occur over field sites and years. The objective was to determine if differences in onion white rot resistance levels were associated with differing S-alk(en)yl-l-cysteine sulfoxide (ACSO) levels. A collection of onion breeding lines and hybrids were evaluated in field trials at six sites in 1999-2001. High performance liquid chromatography was used to analyze ACSOs in onion plant organs. Four main cysteine-sulfoxides exist in Allium L. species: methyl (MCSO), 2-propenyl (2-PeCSO), 1-propenyl (1-PeCSO), and propyl (PCSO). 1-PeCSO was predominant in onion leaves, bulbs, and roots. 2-PeCSO was found in trace amounts in onion leaves and roots. There was significantly more 2-PeCSO and total ACSO (roots only) and 1-PeCSO (roots and bulbs) in accessions that were more susceptible to white rot in the field trials. This is the first report of significant differences in ACSO contents among white rot susceptible and resistant onions. A covariance analysis was used to determine if the ACSO levels that significantly distinguished among accessions could predict field onion white rot reaction. 1-PeCSO from both roots and bulbs was the best predictor of field disease incidence in field sites that had low, moderate, and high disease levels. Although the ACSO concentrations were not assessed on an individual plant basis, breeders may be able to screen onions for resistance to S. cepivorum by comparing onion root or bulb 1-PeCSO levels based on the results from this research. White rot incidence in the field should be higher in those plants whose roots and bulbs have the highest levels of 1-PeCSO.
Ex Situ Conservation of Vegetatively Propagated Species: Development of a Seed-based Core Collection for Malus sieversii
Authors: Volk Gayle M. , Richards Christopher M. , Reilley Ann A. , Henk Adam D. , Forsline Philip L. , Aldwinckle Herb S.
Published: January 2019

Seeds and scionwood of Malus sieversii Lebed. have been collected from wild populations of apple trees in Kazakhstan. Seedlings and grafted trees were planted in the orchards at the U.S. Dept. of Agriculture Plant Genetic Resources Unit in Geneva, N.Y. We developed core collections to capture the genetic and phenotypic diversity represented in the trees from each of two of the Kazakhstan collection sites. These core collections capture more than 90% of the genetic diversity of the original populations, as determined using seven unlinked simple sequence repeat markers and 19 quantitative traits. Since phenotypic evaluations of these materials have been completed, the 35 trees within each population will be used as parents in crosses so that the genetic diversity in the orchard populations can be captured as seed for long-term ex situ conservation. This strategy of storing seeds, rather than maintaining costly field collections, could be applied to other collections of wild plant materials in the National Plant Germplasm System.
Genetic Diversity of Major Greek Olive Cultivars Using Molecular (AFLPs and RAPDs) Markers and Morphological Traits
Authors: Hagidimitriou Marianna , Katsiotis Andreas , Menexes George , Pontikis Constantinos , Loukas Michael
Published: January 2019

The aim of the present study was to develop a reliable reference database to discriminate between the major Greek olive (Olea europaea L.) cultivars and reveal their genetic relationships, since Greece is considered a secondary center of diversity. In order to establish genetic relationships among the 26 Greek and eight international cultivars, four amplified fragment length polymorphism (AFLP) primer pairs, 12 randomly amplified polymorphic DNA (RAPD) primers, along with measurements from 10 morphological traits, were used. A total of 576 AFLP and 113 RAPD markers were produced. Genetic similarities, estimated using the Jaccard algorithim, ranged from 0.45 to 0.83 for the AFLP data and 0.27 to 0.87 for the RAPD data. The cophenetic correlation coefficients between the genetic similarities and the unweighted pair group method of arithmetic averages (UPGMA) phenograms were 0.77 for the AFLPs, 0.81 for the RAPDs, and 0.69 for the morphological traits. However, limited clustering similarities among the phenograms derived from the three methods were observed. This was also reflected by the low correlation between the three genetic similarity matrices produced (AFLP and RAPD, r = 0.39; AFLP and morphological traits, r = 0.11; RAPD and morphological traits, r = 0.02). According to the molecular results, olive cultivars are clustered according to fruit size but not according to geographical origin. Three of the cultivars tested, `Vasilicada,' `Throumbolia', and `Lianolia Kerkiras', were found to branch distantly to the others, according to the AFLP results, and can be considered as ancient Greek cultivars.
Ethanol Production and Chlorophyll Fluorescence Predict Breakdown of Heat-stressed Apple Fruit During Cold Storage
Authors: Fan Lihua , Song Jun , Forney Charles F. , Jordan Michael A.
Published: January 2019

Ethanol concentration and chlorophyll fluorescence (CF) were measured as signs of heat stress in apple fruit [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.]. `McIntosh', `Cortland', `Jonagold', and `Northern Spy' apples were placed in trays and exposed to 46 °C for 0, 4, 8, or 12 hours. Following treatments, fruit were stored in air at 0 °C and evaluated after 0, 1, 2, or 3 months. Ethanol and ethylene production, CF, peel and flesh browning, firmness, skin color, soluble solids, and titratable acidity were measured. Increases in ethanol were apparent immediately following 12-hour heat treatments as well as after 3 months. After 3 months, ethanol concentrations were 16-, 52-, 6-, and 60-fold higher in `McIntosh', `Cortland', `Jonagold', and `Northern Spy' apples than in controls, respectively. The concentrations of ethanol accumulated reflected the degree of heat-induced fruit injury. Heat treatments reduced ethylene production relative to control values. After 3 months of storage ethylene production of fruit exposed to 46 °C for 12 h was <0.48 μmol·kg-1·h-1 compared to >4.3 μmol·kg-1·h-1 for controls. Heat treatments also reduced CF which was expressed as Fv/Fm, where Fv is the difference between the maximal and the minimal fluorescence (Fm - Fo), and Fm is the maximal fluorescence. After 3 months storage at 0 °C, Fv/Fm was ≈0.2 in fruit held at 46 °C for 12 hours compared with 0.5-0.6 for control fruit. Exposure to 46 °C for 12 hours caused severe peel and flesh browning in all cultivars. Severity of peel and flesh browning increased with increasing duration of heat treatment and subsequent storage at 0 °C. `Northern Spy' apple fruit were most susceptible to heat stress based on the degree of flesh browning. Heat treatments of 8 and 12 hours reduced firmness of `McIntosh', `Cortland', and `Northern Spy', but not `Jonagold' apples. Hue angle of the green side of fruit was also reduced in `Cortland', Jonagold' and `Northern Spy' apples receiving the 8- and 12-hour treatments. Heat treatments caused a decrease in fruit tiratable acidity, but had no effect on soluble solids content. The increase in ethanol production and decrease in CF correlated with heat-induced injury, and were apparent before browning was visually apparent. Ethanol and CF have the potential to be used to nondestructively predict the severity of injury that develops during storage.
Pollen Quality and Performance in Strawberry Plants Exposed to High-temperature Stress
Authors: Ledesma Nadine , Sugiyama Nobuo
Published: January 2019

The effects of high-temperature stress on pollen viability and in vitro and in vivo germinability were studied in two facultative, short-day strawberries (Fragaria ×ananassa Duch.), `Nyoho' and `Toyonoka.' Plants were exposed to two day/night temperature regimes of either 23 °C/18 °C (control) or 30 °C/25 °C (high temperature) from when the first inflorescence became visible until anthesis. Pollen viability in `Nyoho' was only slightly affected at 30 °C/25 °C when compared with pollen from plants grown at 23 °C/18 °C. In `Toyonoka', however, pollen viability was significantly lower at 30 °C/25 °C than at 23 °C/18 °C. The in vitro germination percentages were significantly lower in pollen from plants grown at 30 °C/25 °C and germinated at 30 °C than from plants grown at 23 °C/18 °C and germinated at 23 °C in both cultivars. But the percentages were much lower in `Toyonoka' than in `Nyoho', particularly at the 30 °C germination temperature. Pollen from plants grown at 23 °C/18 °C also extended longer pollen tubes than pollen grown at 30 °C/25 °C in both cultivars, but `Nyoho' had longer pollen tubes than `Toyonoka' at 30 °C/25 °C. Fluorescence microscopy revealed that most of the `Nyoho' pollen germinated on the stamen, elongated through the style and reached the ovule regardless of temperature treatment. In `Toyonoka', pollen germination and elongation were greatly inhibited at 30 °C/25 °C, resulting in unfertilized ovules. These results suggest that certain strawberry cultivars produce heat-tolerant pollen, which in turn could result in higher fruit set.
Long Distance Pollen Flow in Mandarin Orchards Determined by AFLP Markers—Implications for Seedless Mandarin Production
Authors: Chao Chih-Cheng T. , Fang Jinggui , Devanand Pachanoor S.
Published: January 2019

Production of seedless mandarins such as `Nules' clementine mandarin (Citrus clementina Hort. Ex Tan.) and `Afourer' mandarin [C. sinensis (L.) Osbeck × C. reticulata Blanco] is increasing in California as consumers' interest in seedless, easy peeling, and good tasting mandarins increases. The fruit would produce seeds if cross-pollination with compatible pollen source occurred. It is almost impossible to prevent cross-pollination between compatible mandarin cultivars by honeybees (Apis mellifera L.) within the multi-faceted agricultural environment in California. To produce seedless mandarin, growers either plant a single cultivar in a large solid block or try to use pollen-sterile navel oranges (C. sinensis) or satsuma mandarins (C. unshiu Marco.) as buffers to prevent cross-pollination. The question of how many rows of buffer trees or spacing can effectively prevent cross-pollination by honeybees between compatible mandarins is unclear. We initiated a study using fluorescent-labeled AFLP markers to determine the pollen parentages of `Nules' clementine seedlings and `Afourer' mandarin seedlings from two orchards in California. The longest distance of pollen flow at an orchard near Madera was 521 m. The pollen of `Minneola' tangelo (C. reticulata × C. paradisi Macf.) was able to disperse across a minimum of 92 rows of `Lane Late' navel oranges plus two rows of `Afourer' mandarins to pollinate `Afourer' mandarins. We also found that all the seedlings of `Nules' clementine mandarin at an orchard near Bakersfield had been pollinated by `Afourer' mandarin pollen. The pollen of `Afourer' mandarin was able to disperse up to distances between 837 and 960 m to pollinate `Nules' clementine. The pollen dispersal distance found in this study was at least 16 times longer than previously reported in a citrus orchard. Growers need to consider a much larger space or buffer rows to prevent cross-pollination and produce seedless mandarins in California.
Pigment Distribution and Total Dissolved Solids of Selected Cycles of Table Beet from a Recurrent Selection Program for Increased Pigment
Authors: Gaertner Veronica L. , Goldman Irwin L.
Published: January 2019

Half-sib recurrent selection programs were initiated at the University of Wisconsin-Madison in 1978 and 1995 to increase betalain (betacyanin and betaxanthin) concentration in red and yellow table beets (Beta vulgaris L. ssp. vulgaris), respectively. Cycles of selection from both the red and yellow table beet breeding programs were evaluated for pigment and total dissolved solids (TDS) distribution in five tissue sections (outer, middle and center zones of the root; leaf and petiole) in two environments (early and late planting) during 2002. Betaxanthin concentration increased with the later planting date in the majority of the tissue zones in the yellow and red table beet populations. Absolute pigment concentration of the outer root zone increased the most over cycles of selection: 46.6 mg/100 g fresh weight (FW) betaxanthin and 201 mg/100 g FW betacyanin for yellow and red populations, respectively. However, the greatest rate of gain was in the center and middle tissue zones. Selection based on the outer 2 cm of root tissue has effectively increased pigmentation of the entire beet plant. A correlated response to selection in leaf and petiole tissue was measured for pigment concentration in both populations. The contribution of each tissue zone to total pigment concentration of the beet plant remained constant throughout cycles of selection averaging 39%, 25%, 25%, 6%, and 5% for outer, middle, center, petiole and leaf tissue zones, respectively. Across all table beet populations, pigment concentration of the outer root zone was 55% and 62% higher than middle and center zones, respectively. TDS of the outer root zone was 10% and 12% higher than middle and center zones, respectively.
Plant Growth, Water Relations, and Transpiration of Spiderplant [Gynandropsis gynandra (L.) Briq.] under Water-limited Conditions
Authors: Masinde P.W. , Stützel H. , Agong S.G. , Fricke A.
Published: January 2019

Plant growth and osmotic adjustment of spiderplant were investigated in a glasshouse and under field conditions. Two fast-growing genotypes (P-landrace and P-commercial) and a slow-growing landrace (G-landrace) were grown under soil water deficit and watered conditions. The fraction of transpirable soil water (FTSW) was used as an indicator of water availability in pots. In the greenhouse, transpiration was determined by changes in daily pot weights and the ratio of transpiration of plants in soil water deficit to watered treatments expressed as normalized transpiration ratio (NTR). Water use in the field experiment was determined by gravimetric methods. The fast-growing genotypes had a higher rate of soil drying due to a higher rate of leaf area development. They were also more sensitive to soil water deficit with NTR beginning to decline at FTSW of 0.55-0.77 as compared to 0.29 for the slow-growing landrace. Also, the fast growing genotypes had FTSW thresholds for the stem elongation rate of 0.35-0.55 as compared to 0.20 for the slow growing landrace. The rate of leaf development declined when 40% to 60% of available water in the soil was removed, regardless of genotype. Leaf area of plants under field conditions decreased when the soil moisture was <60% field capacity. Under severe soil water deficit stress in pots, plants partitioned more biomass to roots than above ground; however, biomass partitioning between leaves and stems was not influenced by soil water deficit. Spiderplant showed limited osmotic adjustment (OA) in the range of 0.10-0.33 MPa at the highest soil water deficit (FTSW = 0). Thus, spiderplant is mainly a drought avoiding species. To achieve maximum growth, it is necessary to keep FTSW above 0.6.
Inheritance of Elastic and Viscoelastic Components of Tomato Firmness Derived from Intra- and Interspecific Genetic Backgrounds
Authors: Stommel John R. , Abbott Judith A. , Campbell T. Austin , Francis David
Published: January 2019

Fruit firmness is a key quality component of tomatoes (Lycopersicon esculentum Mill.) for fresh-market and processed product applications. We characterized inheritance of firmness in processing tomato germplasm developed from interspecific L. esculentum Mill. × L. cheesmanii f. minor (Hook. f.) C.H. Mull. and intraspecific L. esculentum crosses. Although firmness is a key quality attribute of tomato, there is no standard method for measuring it. We measured the elastic portion of firmness by compression (compression Fmax) and puncture (puncture Fmax), and the viscoelastic portion by force-relaxation. The experimental design incorporated six genotypes in a complete 6 × 6 diallel. Compression Fmax and force measurements recorded at 0.5, 1.0, 5.0, and 10.0 seconds of relaxation were strongly related to each other, while relaxation parameters (A, B, C) describing relaxation curve shape were generally independent. Compression Fmax, relaxation curve parameter A, and puncture Fmax were significantly different among hybrids. Significant differences between Maryland and Ohio environments were evident for compression Fmax and relaxation curve parameter A. The patterns of firmness means differed among firmness measurement methods, namely for compression Fmax and puncture Fmax, indicating that they measure different aspects of tomato fruit firmness. Soft-fruited parents generally exerted a negative effect on compression Fmax, whereas firm-fruited parents most often exerted a positive effect on compression Fmax. The force required for fruit compression best approximated subjective assessment of fruit firmness. Force required for fruit puncture was subject to a significant environmental × hybrid influence in the genotypes evaluated. Shape of the force relaxation curve (i.e., parameter A) was not predictive of relative fruit firmness. General combining ability (GCA) and specific combining ability were both significant with GCA being the principal source of genetic variation. In agreement with combining ability estimates, narrow-sense heritability estimates for compression Fmax and puncture Fmax were relatively high.
Expression of the cry1Ac in `Arizona Common' Common Bermudagrass via Agrobacterium-mediated Transformation and Control of Black Cutworm
Authors: Salehi Hassan , Seddighi Zahra , Kravchenko Alexandra N. , Sticklen Mariam B.
Published: January 2019

Bermudagrass (Cynodon L.C. Rich.) is grown on more than 4 million ha in the southern United States. The black cutworm (Agrotis ipsilon Hufnagel) is the most commonly encountered pest of bermudagrass, especially on golf course greens. Developing insect-resistant cultivars is a very desirable substitute, both environmentally and economically, to using current synthetic pesticides. Here we report, for the first time, Agrobacterium-mediated transformation of `Arizona Common' common bermudagrass [Cynodon dactylon (L.) Pers.] with the Bacillus thuringiensis Berliner cry1Ac gene encoding an endotoxin active against black cutworm. Mature seeds were used for producing embryogenic callus, and calli were transformed with a plasmid containing a synthetic cry1Ac and the kanamycin resistance (nptII) genes. Putative transgenic calli and plantlets were selected on media containing 100 and 50 mg·L-1 G418, respectively. RNA-blot analysis of PCR-positive lines revealed the expression of the cry1Ac transgene in three out of five putative transgenic lines. The larvae fed on transgenic plant leaves experienced highly significant (over 80%) mortality.
Changes in Sink-source Relationships during Shoot Development in Olive
Authors: Marchi Susanna , Sebastiani Luca , Gucci Riccardo , Tognetti Roberto
Published: January 2019

Net photosynthesis, dark respiration, chlorophyll and carbohydrate content, and leaf and shoot growth in plants of evergreen olive (Olea europaea L.) grown under controlled conditions were measured to assess changes in carbon balance during leaf development of the 6th, 12th, and 16th node (from the base, first flush) through expansion to maturity. Shoot and leaves expanded in a sigmoid pattern with differences among nodes. Photosynthesis varied with leaf development; young leaves had low CO2 assimilation rates that were reflected in their chlorophyll concentration. Net daily CO2 assimilation was negative in young expanding leaves. The sink-source transition, defined to be the time when the increase in daily carbohydrate exchange rate exceeds the daily increase in leaf carbohydrate content, occurred before full leaf expansion, between 10% and 30% expansion depending on the node.
Genetics of Postharvest Longevity and Quality Traits in Late Generation Crosses of Antirrhinum majus L.
Authors: Weber Jaime A. , Martin William J. , Stimart Dennis P.
Published: January 2019

Progeny of 158 F5 × F5 crosses of Antirrhinum majus (snapdragon) selected within and among cut flower postharvest longevity (PHL) categories (long = 12.6-16.8 days, middle = 9.3-12.1 days, and short = 4.8-8.9 days) were evaluated for PHL and quality traits. Results were compared with previous studies involving F2 × F2 progeny, and F3, F4, and F5 inbred lines. Heritability of PHL in F5 × F5 progeny (0.77 ± 0.11) agrees with that of inbred lines (0.79 to 0.81) but is higher than in F2 × F2 progeny (0.41). Therefore, selection for increased PHL should progress more rapidly and predictably through application of inbred lines rather than F2 individuals. Significant differences between F5 × F5 progeny PHL categories confirm PHL is heritable with a significant additive component. Heritabilities of quality traits in A. majus are high, suggesting selection for quality traits should progress without difficulty. Phenotypic and genotypic correlations of PHL with quality traits are not consistently significant across PHL studies in A. majus. Discrepancies between studies suggest most traits may not be correlated to PHL or are subject to strong environmental influence.
Alteration of Anthocyanin Glycosylation in Cranberry Through Interspecific Hybridization
Authors: Vorsa Nicholi , Polashock James J.
Published: January 2019

The flavonoids of american cranberry (Vaccinium macrocarpon Ait.) are documented to be beneficial for human health. Among their benefits is a high antioxidant potential, with anthocyanin glycosides being the main contributors. Flavonoid glucose conjugates are reported to be more bioavailable than those with other sugar conjugates. The anthocyanin glycosides of V. macrocarpon fruit are mainly galactosides and arabinosides of the aglycones, cyanidin and peonidin, with less than 8% glucosides. In contrast, the fruit anthocyanins of another cranberry species, V. oxycoccus L. were found to be largely glucosides of cyanidin and peonidin. Interspecific hybrids between these two species were intermediate to the parental species in the proportion of fruit anthocyanin glucosides. About half the progeny (1:1 segregation) in a backcross population (to V. macrocarpon) maintained the relatively high anthocyanin glucoside ratio. In this study, we demonstrate the genetic manipulation of anthocyanin glycosylation in cranberry using interspecific hybridization, resulting in dramatically increased glucose-conjugated anthocyanins.