bluuebunny/crossref_metadata_2025 huggingface dataset:
Sucrose Accumulation and Related Metabolizing Enzyme Activities in Seeded and Induced Parthenocarpic Muskmelons
Authors: Hayata Yasuyoshi , Li Xin-Xian , Osajima Yutaka
Published: January 2019

To clarify the cause of low sucrose accumulation in seedless `Crest Earl's' netted muskmelon [Cucumis melo L. (Reticulatus Group)] fruit induced by CPPU, the activity level of sucrose metabolizing enzymes was compared between seeded and seedless fruit. CPPU promoted growth of the ovary in both pollinated and nonpollinated flowers until 10 days after anthesis (DAA), and thereafter the growth rate of nonpollinated fruit was lower than in the controls. Sucrose accumulation of seedless fruit remained lower than in seeded fruit, but there was no difference in fructose and glucose content between seeded and seedless fruit. Acid invertase activity declined sharply 20 DAA in seeded and seedless fruit, and was hardly detectable at 35 DAA, when sucrose accumulation began. Neutral invertase (NI) activity in both seeded and seedless fruit decreased from 20 DAA until 35 DAA; thereafter, NI activity in seeded fruit remained relatively constant, with a small but insignificant increase in maturity. Sucrose synthase (SS-c: sucrose cleavage direction) activity in seeded fruit decreased from 20 to 30 DAA, and then increased as fruit matured, while SS-c activity in seedless fruit did not change during development. Sucrose phosphate synthase (SPS) activity in seeded fruit increased from 25 to 30 DAA and remained relatively constant until harvest. SPS activity in seedless fruit declined gradually from 30 to 45 DAA, then remained at a low level. Sucrose synthase (SS-s: sucrose synthesis direction) activity in seeded fruit increased rapidly after 30 DAA, concomitant with sucrose accumulation. In contrast, SS-s activity in seedless fruit increased only slightly after 30 DAA indicating levels of SS-s activity are closely related to sucrose accumulation in parthenocarpic seedless muskmelons. Chemical name used: [1-(2-chloro-4-pyridyl)-3-phenylurea] (CPPU).
Selection of Day-neutral, Heat-delay-insensitive Dendranthem×grandiflora Genotypes
Authors: Anderson Neil O. , Ascher Peter D.
Published: January 2019

Commercial garden and greenhouse chrysanthemums [Dendranthema ×grandiflora (Ramat.) Kitam. (syn. Chrysanthemum xmorifolium Ramat.)] are facultative short-day plants for flower bud initiation, obligate short-day plants for flower bud development, and are categorized into short-day response groups. Flower initiation can be delayed by high night temperatures. Recent research has identified true day-neutral genotypes. The purpose of this investigation was to test environments for selecting genotypes that are both day-neutral and heat-delay insensitive. One greenhouse and 18 garden genotypes were selected. A series of environments were used to select for day-neutral genotypes and then differentiate between these genotypes for heat delay insensitivity: short days, long days/red light, long days/far red light and high temperatures, and natural day lengths under field conditions. Day-neutral selections from these environments were then grown in a fifth environment of long days/continuous far red and red light with high temperature. Data were collected on the number of days to first and third flower, long day leaf number, stem length, number of strap-shaped leaves subtending the terminal flower, internode lengths, number of nodes with axillary branching, and flower bud development of the first to the sixth flowers. Genotypes required 3 to 8 weeks for complete flower bud initiation/development. Flowering responses in the first four environments were highly significant for both the first and third flowers. Genotypes ranged from obligate short-day to day-neutral for the first six flowers. Three day-neutral genotypes were selected that differed significantly for all traits in the fifth environment; flower bud development with the first six flowers occurred with only one genotype, 83-267-3. Broad sense heritability estimates ranged from h2 = 0.75 for number of nodes with axillary branching, h2 = 0.79 for long day leaf number and number of strap-shaped leaves, to h2 = 0.91 for stem length. An ideotype for day-neutral and heat-delay-insensitive garden chrysanthemums was developed for use in breeding programs.
Early Growth of Muskmelon in Mulched Minitunnels Containing a Thermal Water Tube. II. Air, Soil, and Water Tube Temperatures and Vegetative Growth
Authors: Aziz Fahrurrozi , Stewart Katrine A. , Jenni Sylvie
Published: January 2019

Field experiments were conducted during 1997, 1998, and 1999 to determine effects of 10 combinations of mulched minitunnel and thermal water tube on air, soil, and water-tube temperatures and on vegetative growth of `Earligold' netted muskmelon (Cucumis melo L. Reticulatus Group) within the tunnels. Use of mulched minitunnels significantly increased air, soil and water temperatures during the preanthesis phase in all years compared with control treatments. Inclusion of water tubes and venting the tunnels decreased air temperature fluctuations in the tunnels. During the first 10 to 15 days after transplanting, plants grown in nonperforated tunnels had higher relative growth rates (RGRs), net assimilation rates (NARs), and dry weights (DWs) than those grown under perforated tunnels and control plots. Plants in tunnels containing thermal water tubes generally had higher RGRs, NARs, and DWs than those without tubes. During the later part of the experiment, from 11 to 16 days after transplanting until anthesis, however, there were no consistent effects of mulched minitunnels on RGR, NAR, and plant DW. Tunneled muskmelons had significantly higher RGRs, but generally lower NARs than those grown without tunnel. Use of mulched minitunnels significantly increased plant DW at anthesis in 1997, but not in 1998 and 1999. Plants grown in the minitunnels containing a thermal water tube generally had higher RGRs, NARs, and DWs than those without water tubes. Ventilating nonperforated tunnels generally increased RGR, NAR, and plant DW. Plants grown in the tunnels reached anthesis 10 days earlier than those without tunnels.
Using Volatile Emissions and Chlorophyll Fluorescence as Indicators of Heat Injury in Apples
Authors: Song Jun , Fan Lihua , Forney Charles F. , Jordan Michael A.
Published: January 2019

Volatile emissions and chlorophyll fluorescence were investigated as potential signals of heat injury for apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] fruit. `McIntosh', `Cortland', `Jonagold', and `Northern Spy' apples were exposed to 46 °C for 0, 4, 8, or 12 hours (heat treatments). Following treatments, fruit were kept at 20 °C and evaluated after 1, 2, 4, or 7 days. Heat treatments induced volatile production including ethanol and ethyl acetate. The 8 and 12 hours heat treatments increased ethanol and ethyl acetate production in all four cultivars by as much as 170- and 11-fold, respectively, 1 day after treatments. Heat treatments also reduced ethylene production and chlorophyll fluorescence. Heat for 12 hours caused serious flesh browning. Among the cultivars investigated, `Northern Spy' and `McIntosh' were most susceptible to heat stress based on the degree of flesh browning. Correlation coefficients of heat stress induced ethanol emission and chlorophyll fluorescence with flesh browning were 0.82 and -0.66, respectively. The nondestructive measurements of ethanol emission and chlorophyll fluorescence have potential to identify stressed fruit with reduced quality or compromised storage life.
Histogenic Identification by RAPD Analysis of Leaves and Fruit of Newly Synthesized Chimeric Citrus
Authors: Sugawara Kuniaki , Wakizuka Takumi , Oowada Atsushi , Moriguchi Takaya , Omura Mitsuo
Published: January 2019

Randomly amplified polymorphic DNA (RAPD) analysis was used to investigate the histogenic structure of leaf and fruit tissues in four graft chimeras, two intentional chimeras that were produced in combination with `Hamlin' orange [Citrus sinensis (L.) Osbeck] and `Satsuma' mandarin (C. unshiu Marc.), and two naturally occurring periclinal chimera cultivars, Kobayashi Mikan (a graft chimera of C. unshiu and C. natsudaidai Hayata), and Kinkoji Unshu (a graft chimera of C. unshiu and C. obovoidea hort. ex Takahashi). RAPD profiles of the lamina epidermis and the mesophyll cells of specific individuals indicated that the four graft chimeras were interspecific monekto chimeras, whose outermost layer (histogenic layer L-1) of the shoot apical meristem consisted of a species that was different from that in the inner layers (histogenic layers L-2 and L-3). Moreover, juice vesicles, which develop from the inside cells of the pericarp and become the main edible parts of Citrus fruit, were a mixture of the cells from both parental source cultivars. Therefore, the vesicles were at least composed of L-1 and subepidermal inner L-2 cells. This determination of interspecific chimeral construction (which was made possible by molecular techniques) is a valuable finding, in terms of improving Citrus through intentional use of periclinal chimerism.
Comparison of Nitrification Rates in Blueberry and Forest Soils
Authors: Hanson Eric J. , Throop Philip A. , Serce Sedat , Ravenscroft John , Paul Eldor A.
Published: January 2019

Highbush blueberries (Vaccinium corymbosum L.) are long lived perennial plants that are grown on acidic soils. The goal of this study was to determine how blueberry cultivation might influence the nitrification capacity of acidic soils by comparing the nitrification potential of blueberry soils to adjacent noncultivated forest soils. The net nitrification potential of blueberry and forest soils was compared by treating soils with 15N enriched (NH4)2SO4, and monitoring nitrate (NO3--N) production during a 34-day incubation period in plastic bags at 18 °C. Net nitrification was also compared by an aerobic slurry method. Autotrophic nitrifiers were quantified by the most probable number method. Nitrate production from labeled ammonium (15NH4+) indicated that nitrification was more rapid in blueberry soils than in forest soils from six of the seven study sites. Slurry nitrification assays provided similar results. Blueberry soils also contained higher numbers of nitrifying bacteria compared to forest soils. Nitrification in forest soils did not appear to be limited by availability of NH4+ substrate. Results suggest that blueberry production practices lead to greater numbers of autotrophic nitrifying bacteria and increased nitrification capacity, possibly resulting from annual application of ammonium containing fertilizers.
Reduced Container Volume Increases Tomato Pollen Fertility at Low Ambient Temperatures
Authors: Domínguez Eva , Cuartero Jesús , Fernández-Muñoz Rafael
Published: January 2019

Using soil bed cultivations as controls and under two temperature regimes (maximum/minimum ≈20/4 °C and 25/10 °C), effects of container volume (16-, 10-, and 3-L pots) on in vitro germination, in vivo tube growth, acetocarmine staining, and quantity of pollen of tomato [Lycopersicon esculentum Mill. `Moneymaker', L. pennellii (Corr.) D'Arcy accession PE-45, and of the corresponding F1 hybrid] were studied. Under the 20/4 °C regime, in comparison with soil-bed cultivated control plants, the cold sensitive cultivar, Moneymaker, grown in the two smaller pots showed significant increases of in vitro pollen germination, acetocarmine staining, and number of pollen grains produced per flower. Similar results were observed with the F1 except for the number of pollen grains which were not significantly different. Pollen of accession PE-45 was unaffected by cold and no container effect was detected. Results of in vivo pollen tube growth in `Moneymaker' at the 20/4 °C regime showed that fruit set was only possible in 3-L pots. Reduction of the negative effects of cold on pollen from plants grown in the 3-L pots may be explained in part by the daytime rise of root-zone temperatures that did not occur in the 10- or 16-L pots or in the soil bed. Therefore, fruit production of tomato plants grown under low temperatures in small pots may not be a valid predictor of commercial winter fruit production of plants cultivated in soil beds.
Soluble Carbohydrates in Two Buffalograss Cultivars with Contrasting Freezing Tolerance
Authors: Ball S. , Qian Y.L. , Stushnoff C.
Published: January 2019

No information is available regarding endogenous soluble carbohydrate accumulation in buffalograss [Buchloe dactyloides (Nutt.) Engelm.] during cold acclimation. The objective of this study was to determine composition of soluble carbohydrates and their relationship to freezing tolerance in two buffalograss cultivars, 609 and NE 91-118, with different freezing tolerances. The experiment was conducted under natural cold acclimation conditions in two consecutive years in Fort Collins, Colo. Based upon average LT50 (subfreezing temperature resulting in 50% mortality) from seven sampling intervals in 1998-99 and six sampling intervals in 1999-2000, `NE 91-118' survived 4.5 °C and 4.9 °C colder temperatures than `609', during the 1998-1999 and 1999-2000 winter seasons, respectively. Glucose, fructose, sucrose, and raffinose were found in both cultivars in both years, and were generally higher in acclimated than pre- and post-acclimated stolons. Stachyose was not present in sufficient quantities for quantification. Cultivar NE 91-118 contained 63% to 77% more glucose and 41% to 51% more raffinose than `609' in the 1998-99 and 1999-2000 winter seasons, respectively. In 1999-2000, fructose content in `NE 91-118' was significantly higher than that of `609'. A significant negative correlation was found between LT50 vs. all carbohydrates in 1999-2000, and LT50 vs. sucrose and raffinose in 1998-99. Results suggest that soluble carbohydrates are important in freezing tolerance of buffalograss.
Vacuolar Acidification in Citrus Fruit: Comparison between Acid Lime (Citrus aurantifolia) and Sweet Lime (Citrus limmetioides) Juice Cells
Authors: Brune Andreas , Müller Mathias , Taiz Lincoln , Gonzalez Pedro , Etxeberria Ed
Published: January 2019

Vacuolar acidification was investigated in `Palestine' sweet (Citrus limmetioides Tanaka) and `Persian' acid lime [(Citrus aurantifolia (Christm.) Swingle] (vacuolar pHs of 5.0 and 2.1, respectively) using tonoplast vesicles isolated from juice cells. The ATPase activity of tonoplast-enriched vesicles from sweet limes was strongly inhibited by bafilomycin A1 and NO3-, but was unaffected by vanadate. In contrast, the ATPase activity in acid lime membranes was only slightly inhibited by bafilomycin A1 and NO3- and was strongly inhibited by high concentrations of vanadate. The vacuolar origin of the acid lime vesicles was confirmed by immunoblotting. After solubilization and partial purification of the two enzymes by gel filtration, their inhibitor profiles were largely unchanged. Based on equal ATPase activities, vesicles from sweet and acid limes were able to generate similar pH gradients. However, in tonoplast vesicles from sweet limes, the maximum ΔpH was reached four times faster than in those from acid limes. Addition of ethylenediamine tetraacetic acid (EDTA) to chelate Mg+2 after the maximal ΔpH was attained resulted in collapse of the pH gradient in vesicles from sweet limes, whereas no change in ΔpH was observed in vesicles from acid limes, indicating a less H+ permeable membrane. Vacuolar ATPases from both cultivars exhibited identical pH optima and showed similar Mg+2 dependence, but only the acid lime ATPase activity was inhibited by Ca+2. These data confirm that the vanadate-sensitive form of the V-ATPase found in lemon and acid limes is specific to hyperacidifying tissues rather than to citrus juice cells. Sweet lime vacuoles bear the classical V-ATPase also found in vegetative plant tissues.
Humic Acid Application Does Not Improve Salt Tolerance of Hydroponically Grown Creeping Bentgrass
Authors: Liu Chunhua , Cooper R.J.
Published: January 2019

Growth and mineral nutrient content of creeping bentgrass [Agrostis stolonifera (L.) var. palustris (Huds.) Farw.] in response to salinity and humic acid (HA) application were investigated, and the effects of HA application on salinity tolerance was evaluated. Bentgrass plugs were grown hydroponically in one-quarter-strength Hoagland's nutrient solution containing HA at 0 or 400 mg·L-1 with salinity levels of 0, 8.0, or 16.0 dS·m-1. Clipping dry weight (DW), tissue water content, and net photosynthesis (PN) were measured weekly for 1 month. Maximum root length, and root DW from 0 to 10 cm and >10 cm root zones were determined 31 days after treatment (DAT). The turfgrass plugs were mowed three times weekly, with clippings collected and dried for mineral nutrient analysis. Salinity was inversely related to clipping DW, tissue water content, PN, and maximum root length. Salinity had less effect on root growth than top growth. HA treatment did not affect tissue water content, PN, or root growth of salt-stressed turf. Salinity decreased uptake of N, P, K, Ca, and S; increased uptake of Mg, Mn, Mo, B, Cl, and Na; and had no influence on uptake of Fe, Cu, and Zn. Application of HA at 400 mg·L-1 during salinity stress neither increased uptake of the mineral nutrients inhibited by salinity, nor decreased uptake of nutrients which were excessive and toxic in the salinity solution. In general, application of HA did not improve salinity tolerance of creeping bentgrass.
Genetic Analysis of Quantitative Traits in Pepino (Solanum muricatum) in Two Growing Seasons
Authors: Rodríguez-Burruezo A. , Prohens J. , Nuez F.
Published: January 2019

Twenty-six clones of pepino (Solanum muricatum Aiton) were evaluated for yield, fruit weight, fruit shape (length to width ratio), soluble solids concentration (SSC), titratable acidity (TA), and ascorbic acid concentration (AAC) over two growing seasons: autumn-winter (AW) and spring-summer (SS). Significant differences were found for the effects of clone, season, and clon× season interaction for all traits, except in the case of season for fruit shape. Mean values for yield, SSC, and AAC were higher in the AW than in the SS season, while mean fruit weight and TA were lower. Many clones (13 in AW and six in SS) had a yield higher than 30 t·ha-1. Substantial genotypic variation was found for all traits studied except for SSC. Clones stable for all traits were detected over both seasons, except for SSC, where the differences between seasons were very high. The significant clone × season interaction for all traits indicates that selection of genotypes adapted specifically to either AW or SS seasons would maximize the response to selection. Broad sense heritabilities were highest for fruit shape and yield (>0.70), while SSC had the lowest values (0.39 in AW, 0.17 in SS, and almost 0 when considering both seasons combined). For the AW season, significant fruit weight-SSC and fruit weight-AAC genotypic correlations were detected; for the SS season the significant genotypic correlations were yield-SSC, fruit weight-TA, fruit shape-TA, and SSC-TA. Results suggest there are ample opportunities for improving several traits in this crop using intraspecific variation for adaptation to specific environments.
Roles of Sorbitol and Sucrose in Growth and Respiration of `Encore' Peaches at the Three Developmental Stages
Authors: Bianco Riccardo Lo , Rieger Mark
Published: January 2019

In peach [Prunus persica (L.) Batsch (Peach Group)], both sorbitol and sucrose are used for source to sink carbon (C) transport, yet their specific functions in fruit growth and development remain unclear. Growth rate (GR), respiration rate (R), carbohydrate content, and the activities of sorbitol dehydrogenase (SDH), sorbitol oxidase (SOX), sucrose synthase (SS), acid invertase (AI), and neutral invertase (NI) were determined in `Encore' peaches to study the specific functions of sorbitol and sucrose in each phase of fruit development (an early period of rapid cell division, a relatively inactive intermediate stage where endocarp (pit) hardening occurs, and a final swelling due to cell expansion). Fruit growth and respiration rates (mol C/fruit per day) were always positively correlated, but the growth coefficient (gc) relating them was significantly higher at cell division, when maintenance respiration (Rm) was nearly absent. Sorbitol and sucrose appeared to participate equally in growth and maintenance respiration. Contents of sorbitol and sucrose both correlated positively to GR, and their rates of accumulation increased from early to late growth stages in similar fashion. SDH activity was always positively correlated with sink strength and GR, but with R only at endocarp hardening (r = 0.632). SOX activity was also correlated with sink strength and GR in the early (r = 0.514 and 0.553) and late (r = 0.503 and 0.495) growth phases, but not at endocarp hardening, and was correlated with R in two of three growth phases. Among sucrose cleavage enzymes, AI activity was positively correlated with sink strength, GR, and R more strongly than the others (r = 0.51 to 0.80), but only in the cell division and cell expansion periods. SS activity was correlated with sink strength and R only at endocarp hardening, and NI activity was generally not correlated to sink strength, GR, or R. We conclude that sorbitol and sucrose play similar roles in fruit development, and the enzymes associated with their metabolism work in concert to produce the observed changes in growth and respiration.
Anatomical and Histochemical Factors Associated with Bronzing Development in Strawberry Fruit
Authors: Polito Vito S. , Larson Kirk D. , Pinney Katherine
Published: January 2019

Bronzing of strawberry (Fragaria ×ananassa Duchesne) fruit that is not the result of arthropod feeding or chemical spray application occurs frequently in California's central coast strawberry production region from late spring through midsummer, a period characterized by relatively high temperature, low relative humidity, and high solar irradiance. The cause of this phenomenon is not known, but in preliminary trials, intermittent, midday misting of plants and increased drip irrigation rate resulted in reduced incidence of fruit bronzing. To characterize the bronzing phenomenon and its development in strawberry fruit tissues, we conducted an anatomical and histochemical examination of bronzed fruit. Bronzed and nonbronzed fruit were sampled over a range of fruit maturities. Results show that bronzing derives from a lesion at the cortical surface early in the fruit's development. Epidermal cells become radially compressed and the cell contents coalesce into a densely staining mass. The cuticular layer becomes disrupted and discontinuous. As the fruit develops, densely staining materials, possibly phenolic precipitates, accumulate within subepidermal cells of bronzed fruit, subepidermal cell walls thicken, and intercellular spaces fill with pectic substances and other densely staining materials. Results are consistent with reports of sunscald injury from other fruit species, and raise the possibility that strawberry bronzing occurs in response to heat or solar radiation injury.
Tagging and Mapping Scab Resistance Genes from R12740-7A Apple
Authors: Hemmat Minou , Brown Susan K. , Weeden Norman F.
Published: January 2019

The genetic basis of resistance to apple scab [Venturia inaequalis (Cke.) Wint.] in the Russian apple seedling R12740-7A (Malus Mill. sp.) was investigated. Segregation ratios obtained in crosses with susceptible cultivars suggested that at least two genes were involved, and three foliar resistance reactions (chlorotic, stellate necrotic, and pit type) were observed after inoculation. DNA markers were identified for both the stellate necrotic (Vr) and pit type (no locus designation, Vx suggested) resistance phenotypes. Comparison of resistance phenotypes with marker segregation demonstrated that only two major dominant genes were present in R12740-7A, one producing the stellate necrotic lesion and the other the pit-type lesion. The chlorotic lesion could be attributed to either unclear expression of the resistance phenotype or to susceptible genotypes not contracting the disease. These markers along with a previously published marker for Vf were used to analyze inheritance of resistance in a Vr × Vf cross in advanced breeding material. The markers identified successfully all susceptible progeny, as well as apparent escapes and individuals possessing both Vf and Vr. Thus, the markers should be useful in future screening of segregating progeny and in the pyramiding of scab resistance genes in new cultivars.
Hot Water Immersion as a Quarantine Treatment for Large Mangoes: Artificial versus Cage Infestation
Authors: Shellie K.C. , Mangan R.L.
Published: January 2019

Market demand exists in the United States for fresh mango (Mangifera indica L.) fruit weighing >700 g, yet fruit of this size cannot be imported for lack of a quarantine treatment against fruit flies (Diptera: Tephritidae). Therefore, the objectives of this research were to evaluate the influence of fruit infestation method on mortality of late third instar, fruit fly larvae after fruit were immersed in hot water, and to generate dose mortality and fruit quality data for mangoes >700 g. Results suggested that artificial infestation is preferable to cage infestation because artificial infestation eliminates the direct influence of fruit weight loss on the heat dose delivered to the fruit center. Other advantages of artificial over cage infestation include: fruit maturity at treatment is similar to commercial application, mortality of untreated control fruit can be calculated, larval maturity is uniform and observable, and larvae can be placed into the slowest heating part of the fruit. Infesting with 50 rather than 25 larvae per fruit was preferred because the number of larvae placed into the fruit did not influence mortality and twice as many larvae were evaluated using the same number of fruit. The dose mortality and fruit quality data generated in this research suggest that immersion in water at 46.1 °C for 110 minutes may provide Probit 9 level quarantine security against Mexican fruit fly (Anastrepha ludens Loew) for mangoes weighing up to 900 g without adversely affecting fruit market quality.
Methyl Jasmonate Enhances Anthocyanin Accumulation and Modifies Production of Phenolics and Pigments in `Fuji' Apples
Authors: Rudell D.R. , Mattheis J.P. , Fan X. , Fellman J.K.
Published: January 2019

Effects of artificial ultraviolet-visible light and methyl jasmonate (MJ) treatment on `Fuji' apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] fruit peel anthocyanin, phenolic, carotenoid, and chlorophyll production were examined using tristimulus color analysis and reverse-phase high performance liquid chromatography. Anthocyanin synthesis was enhanced by light and MJ treatment. Chlorogenic acid and most cyanidin, quercetin, and phloretin glycosides increased with MJ treatment concentration. Light alone also promoted increased production of most of these compounds. Production of catechin, (-)epicatechin, quercetin, and quercetrin was not enhanced by either light or MJ treatment. Light and MJ enhanced ß-carotene and chlorophyll b, synthesis but not xanthophyll or chlorophyll a synthesis. The chlorophyll a/b ratio decreased with MJ dosage. Results suggest MJ may provide a viable means of enhancing apple fruit coloration and other photoprotective mechanisms. Chemical name used: methyl 3-oxo-2-(2-pentenyl)cyclopentane-1-acetate (methyl jasmonate).
Development and Evaluation of Potatoes Transgenic for a cry1Ac9 Gene Conferring Resistance to Potato Tuber Moth
Authors: Davidson Melanie M. , Jacobs Jeanne M.E. , Reader Jill K. , Butler Ruth C. , Frater Christina M. , Markwick Ngaire P. , Wratten Steve D. , Conner Anthony J.
Published: January 2019

Transgenic potato (Solanum tuberosum L.) lines of two cultivars, Ilam Hardy and Iwa, were developed using Agrobacterium-mediated transformation to transfer a cry1Ac9 gene under the transcriptional control of the CaMV 35S promoter. PCR confirmed the presence of the nptII selectable marker gene in all recovered lines. All ten lines of Ilam Hardy and 14 of 15 Iwa lines were PCR-positive for the cry gene. In greenhouse trials, all Ilam Hardy transgenic lines produced phenotypically normal plants and significantly inhibited larval growth of potato tuber moth (Phthorimaea operculella Zeller). In contrast, only 60% of the Iwa transgenic lines produced phenotypically normal plants, but all lines positive for the cry gene significantly inhibited larval growth. All transgenic lines with a greenhouse appearance equivalent to the nontransgenic controls and improved resistance to potato tuber moth larvae were planted in the field. Three of the ten Ilam Hardy lines and two of the eight Iwa lines retained phenotypically normal appearance in the field and produced tuber yields equivalent to the nontransgenic controls. All five of these transgenic lines significantly inhibited larval growth of potato tuber moth on excised field-grown leaves. A high correlation was established between larval growth indices from the greenhouse and the field. A transgenic line from each cultivar inhibited larval growth by over 40%, and the line derived from Ilam Hardy prevented pupation of all larvae. Southern analysis on these five elite lines revealed that they contained either one or two copies of the cry1Ac9 gene. The amount of Cry protein in all transgenic lines tested was less than 60 ng·g-1 of fresh leaf tissue. A transgenic line from each cultivar was identified with comparable phenotypic appearance and yield to their parent cultivars coupled with high resistance to PTM.
STS Markers for Comparative Mapping in Legumes
Authors: Brauner S. , Murphy R.L. , Walling J.G. , Przyborowski J. , Weeden N.F.
Published: January 2019

DNA primers for 37 genes have been developed in pea (Pisum sativum L.). Two-thirds of these primers also amplify orthologous sequences in lentil (Lens culinaris). The primers were designed to be complementary to highly conserved sequences in exons of known genes. In addition, most of the priming sequences were selected to be 1000 to 3000 bp distant on the genomic DNA and to amplify a fragment that contained at least one intron. Segregating sequence polymorphism in mapping populations of recombinant inbred lines (RILs) derived from wide crosses in Pisum was observed by restriction of the amplified fragment with endonucleases recognizing four-base restriction sites. Successful mapping of 36 of these genes in pea demonstrated the utility of these primers for mapping, and it appears likely that the primers should have general utility for comparative mapping in legumes.
Greenhouse Mist Improves Yield of Tomato Plants Grown under Saline Conditions
Authors: Romero-Aranda R. , Soria T. , Cuartero J.
Published: January 2019

High salinity levels in irrigation water available in Mediterranean coastal areas induce a significant loss of yield in greenhouse tomato crops. This loss increases during the spring-summer growing season when high irradiance, temperature, and low humidity occur within greenhouses. This study determined whether salt-induced yield losses could be alleviated by increasing humidity by misting the greenhouse atmosphere. Plants of `Daniela' tomato (Lycopersicon esculentum Mill.), were irrigated with 0 or 50 mm NaCl added to the nutrient solution and grown under natural greenhouse conditions or under applications of fine mist every 8 min during the day. During midday hours, misting reduced greenhouse air vapor pressure deficit 1.0 to 1.5 kPa and reduced greenhouse air temperature 5 to 7-°C. Mist reduced root water uptake from the medium by 40% in nonsalinized plants and by 15% in saline conditions. Foliar concentration of Na was lower in misted-salinized plants than in nonmisted salinized plants. Less negative leaf water potential and higher leaf turgor were recorded with mist at midday, in both salinized and nonsalinized plants. Midday stomatal conductances and net CO2 assimilation rates of salinized-misted plants were 3 and 4 times higher, respectively, than those recorded in salinized-nonmisted plants. Misted plants increased instantaneous water use efficiency 84% to 100%, as estimated from the ratio of net CO2 assimilation to transpiration. Nonsalinized plants grown with mist increased total leaf area by 38%, dry matter by 10%, and yield by 18% over nonmisted plants. Salinized plants grown with mist increased total plant leaf area by 50%, dry matter by 80%, and yield by 100%. Greenhouse misting resulted in a saving of total water input of 31 L/plant under nonsaline conditions and in greater yields and fruit size regardless of salinity. Results suggest that greenhouse misting, during the Mediterranean spring-summer growing season, improves tomato crop productivity both under nonsaline and saline growth conditions.
Identification of RAPD Markers Linked to Five Marker Genes (blu, dgs, y, arg, and a Flat Pod Mutant) in Common Bean
Authors: Beltrán Gino E. , Jung Geunwha , Nienhuis James , Bassett Mark J.
Published: January 2019

The development of a complete linkage map, including both classical (visible) and molecular markers, is important to understand the genetic relationships among different traits in common bean (Phaseolus vulgaris L.). The objective of this study was to integrate classical marker genes into previously constructed molecular linkage maps in common bean. Bulked segregant analysis was used to identify 10 random amplified polymorphic DNA (RAPD) markers linked to genes for five classical marker traits: dark green savoy leaf (dgs), blue flower (blu), silvery [Latin: argentum] green pod (arg), yellow wax pod (y) and flat pod (a spontaneous mutation from round to flat pod in `Hialeah' snap bean). The genes for dark green savoy leaf (dgs) and blue flower (blu) were located in a previously constructed molecular linkage map. These results indicate that classical marker genes and molecular markers can be integrated to form a more complete and informative genetic linkage map. Most of the RAPD markers were not polymorphic in the two mapping populations used, and molecular markers from those mapping populations were not polymorphic in the F2 populations used to develop the RAPD markers. Alternative genetic hypotheses for the pod shape mutation in `Hialeah' are discussed, and the experimental difficulties of pod shape classification are described.
Determining Ploidy Level and Nuclear DNA Content in Rubus by Flow Cytometry
Authors: Meng Rengong , Finn Chad
Published: January 2019

Nuclear DNA flow cytometry was used to differentiate ploidy level and determine nuclear DNA content in Rubus. Nuclei suspensions were prepared from leaf discs of young leaves following published protocols with modifications. DNA was stained with propidium iodide. Measurement of fluorescence of 40 genotypes, whose published ploidy ranged from diploid to dodecaploid, indicated that fluorescence increased with an increase in chromosome number. Ploidy level accounted for 99% of the variation in fluorescence intensity (r2 = 0.99) and variation among ploidy levels was much higher than within ploidy levels. This protocol was used successfully for genotypes representing eight different Rubus subgenera. Rubus ursinus Cham. and Schldl., a native blackberry species in the Pacific Northwest, which has been reported to have 6x, 8x, 9x, 10x, 11x, and 12x forms, was extensively tested. Genotypes of R. ursinus were predominantly 12x, but 6x, 7x, 8x, 9x, 11x, and 13x forms were found as well. Attempts to confirm the 13x estimates with manual counts were unsuccessful. Ploidy level of 103 genotypes in the USDA-ARS breeding program was determined by flow cytometry. Flow cytometry confirmed that genotypes from crosses among 7x and 4x parents had chromosome numbers that must be the result of nonreduced gametes. This technique was effective in differentiating chromosome numbers differing by 1x, but was not able to differentiate aneuploids. Nuclear DNA contents of 21 diploid Rubus species from five subgenera were determined by flow cytometry. Idaeobatus, Chamaebatus, and Anaplobatus were significantly lower in DNA content than those of Rubus and Cylactis. In the Rubus subgenus, R. hispidus and R. canadensis had the lowest DNA content and R. sanctus had the highest DNA content, 0.59 and 0.75 pg, respectively. Idaeobatus had greater variation in DNA content among diploid species than the Rubus subgenus, with the highest being from R. ellipticus (0.69 pg) and lowest from R. illecebrosus (0.47 pg).
Genotype/Genotype × Environment Biplot Analysis for Cultivar Evaluation and Mega-environment Investigation in Primocane-fruiting Red Raspberry
Authors: Sullivan J.A. , Yan Weikai , Privé J.P.
Published: January 2019

Primocane-fruiting (PF) red raspberry (Rubus idaeus L.) cultivars are being grown in many regions as their popularity increases. However, testing of this perennial fruit crop is expensive and requires many years. Large genotype (G) × environment (E) interactions can make identification of superior genotypes difficult. The G/G × E (GGE) biplot can be used to measure cultivar performance and group locations into mega-environments. The GGE biplot was applied to yield trial data of three PF red raspberry cultivars Autumn Bliss, Heritage, and Redwing grown in 17 environments (year-location combinations). The 17 environments encompassed six locations in Ontario and Quebec, Canada between 1989 and 1996. `Autumn Bliss' produced the highest yields in 11 of 17 environments. `Heritage' was usually the lowest yielding cultivar. Two mega-environments were identified based on the performance of `Autumn Bliss' and `Redwing'. Some environmental variables were likely to be responsible for the discriminating ability of the test environments as they were correlated with the primary effects. The GGE biplot was an effective analysis to determine mega-environments and the cultivars best adapted to each.
Resistance to Sweetpotato Chlorotic Stunt Virus and Sweetpotato Feathery Mottle Virus Is Mediated by Two Separate Recessive Genes in Sweetpotato
Authors: Mwanga R.O.M. , Kriegner A. , Cervantes-Flores J.C. , Zhang D.P. , Moyer J.W. , Yencho G.C.
Published: January 2019

When sweetpotato chlorotic stunt crinivirus (SPCSV) and sweetpotato feathery mottle potyvirus (SPFMV) infect sweetpotato [Ipomoea batatas (L.) Lam.], they interact synergistically and cause sweetpotato virus disease (SPVD), a major constraint to food productivity in east Africa. The genetic basis of resistance to these diseases was investigated in 15 sweetpotato diallel families (1352 genotypes) in Uganda, and in two families of the same diallel at the International Potato Center (CIP), Lima, Peru. Graft inoculation with SPCSV and SPFMV resulted in severe SPVD symptoms in all the families in Uganda. The distribution of SPVD scores was skewed toward highly susceptible categories (SPVD scores 4 and 5), eliminating almost all the resistant genotypes (scores 1 and 2). Likewise, when two promising diallel families (`Tanzania' × `Bikilamaliya' and `Tanzania' × `Wagabolige') were graft inoculated with SPCSV and SPFMV at CIP, severe SPVD was observed in most of the progenies. Individual inoculation of these two families with SPCSV or SPFMV, and Mendelian segregation analysis for resistant vs. susceptible categories led us to hypothesize that resistance to SPCSV and SPFMV was conditioned by two separate recessive genes inherited in a hexasomic or tetradisomic manner. Subsequent molecular marker studies yielded two genetic markers associated with resistance to SPCSV and SPFMV. The AFLP and RAPD markers linked to SPCSV and SPFMV resistance explained 70% and 72% of the variation in resistance, respectively. We propose naming these genes as spcsv1 and spfmv1. Our results also suggest that, in the presence of both of these viruses, additional genes mediate oligogenic or multigenic horizontal (quantitative) effects in the progenies studied for resistance to SPVD.
Greenhouse Covering Materials and Supplemental Lighting Affect Growth, Yield, Photosynthesis, and Leaf Carbohydrate Synthesis of Tomato Plants
Authors: Erhioui Badrane M. , Gosselin André , Hao Xiuming , Papadopoulos Athanasios P. , Dorais Martine
Published: January 2019

A study was conducted in mini-greenhouses covered with single-glass (glass), double inflated polyethylene film (D-poly), or rigid twin acrylic panels (acrylic) to determine the effects of covering materials and supplemental lighting (SL) (65 μmol·m-2·s-1 at 1 m from the ground, providing a 16-hour photoperiod) on growth, yield, photosynthesis, and leaf carbohydrate concentration of `Trust' greenhouse tomato plants (Lycopersicon esculentum Mill.). Regardless of the light treatment, the marketable yield (kg·m-2) and the number of fruit per square meter in D-poly houses were higher (P ≤ 0.05) by 15% to 16% and 13% to 17%, respectively, than in glasshouses. Under supplemental lighting (SL), similar results were observed in acrylic houses compared to glasshouses. Covering materials had no significant effect on photosynthesis and leaf chlorophyll (chl) concentration. SL increased the number of leaves (March) by 15% (P ≤ 0.05) in glasshouses, marketable fruit yield by 23% (P ≤ 0.01) in acrylic houses, leaf specific weight by 19% to 33% (P ≤ 0.05) in all houses, total chl concentration by 10% to 14% (P ≤ 0.01) in acrylic houses, and photosynthetic rate (March) by 22% (P ≤ 0.01) in glasshouses. Under nonsupplemental lighting (nonSL, daily solar radiation of 8.42 MJ·m-2), plant height in acrylic houses was significantly higher (P ≤ 0.05) than in glasshouses. Neither covering materials nor SL affected (P ≤ 0.05) dry matter allocation to the fruit. Results suggest that D-poly and acrylic houses with SL provide the best environment for the early yield (February to March) under southwestern Ontario growing conditions. The photosynthetic rate decreased (P ≤ 0.05) by 18% in acrylic, and 15% in D-poly and glasshouses after 2 months of growth under nonSL. Conversely, the decrease in carbon exchange rate was not significant in D-poly houses and glasshouses under SL. As a result, the photosynthesis decline observed in the present study could not be explained by leaf starch accumulation in March.
Nitrogen Uptake by Table Beet—Validation of a Model
Authors: Feller Carmen , Fink Matthias
Published: January 2019

To reduce nitrogen (N) losses from vegetable fields, fertilizer recommendations should be adjusted according to the large range in yield and thus in N uptake of vegetable crops. Therefore, a model was used to predict total N uptake based on expected yield. The model has been validated successfully in a series of studies for Brussels sprouts (Brassica oleracea L. var. gemmifera), white cabbage (Brassica oleracea L. var. capitata) and kohlrabi (Brassica oleracea L. var. gongylodes). The objective of this study was to validate the model for table beet (Beta vulgaris L. var. conditiva), a crop with a considerable variability in N uptake, which is caused by a large potential range of selecting sowing dates, plant densities and cultivars. Field experiments were carried out over two years. Fifty-five combinations of N fertilizer levels, plant densities, cultivars and sowing dates were tested. Plants were sampled at 2- or 3-week intervals, and fresh matter, dry matter and N content of leaves and roots were measured. Crop specific model parameters for table beets were determined from independent data. The model wverestimated N uptake for N-limiting conditions, but for optimally fertilized table beets measured and estimated N uptake showed a close correlation (R2 = 0.93) when total yield was used as an input parameter for the model. Although the error of estimation (35 kg·ha-1) was considerable, studies with other vegetable crops using the model found the error even higher if other tools, such as look-up tables, were used for predicting N uptake.
In Situ Estimation of Carbon Balance of In Vitro Sweetpotato and Tomato Plantlets Cultured with Varying Initial Sucrose Concentrations in the Medium
Authors: Kubota Chieri , Ezawa Makiko , Kozai Toyoki , Wilson Sandra B.
Published: January 2019

The effects of initial sucrose (suc) concentrations in the medium (S0) on the carbon balance and growth of sweetpotato [Ipomoea batatas (L.) Lam. `Beniazuma'] and tomato (Lycopersicon esculentum Mill. `HanaQueen') plantlets were studied under controlled environmental conditions. Plantlets were cultured with 0, 7.5, 15, or 30 g·L-1 of S0 under high photosynthetic photon flux (160 to 200 μmol·m-2·s-1) and CO2 enriched (1400 to 2050 μmol·mol-1) conditions. Net photosynthetic rate per leaf area (Pl) decreased and dry weight per plantlet (Wd) increased with increasing S0, but did not differ significantly between S0 of 7.5 to 30 g·L-1 for sweetpotato or 15 to 30 g·L-1 for tomato. Carbon influxes and effluxes of the plantlets by metabolism of medium suc and/or photosynthesis, and respiration were estimated based on measurements of in situ and steady state CO2 exchange rates and sugar uptake during culture. At S0 from 7.5 to 30 g·L-1, photosynthesis was responsible for 82% to 92% and 60% to 67% of carbohydrate assimilation for sweetpotato and tomato, respectively. Estimated carbon balances of plantlets based on the estimated and actual increases of moles of carbon in plant tissue demonstrated that in situ estimation of carbon balance was reasonably accurate for sweetpotato at S0 of 0 to 15 g·L-1 and for tomato at S0 of 0 g·L-1 and that the actual contribution of photosynthesis for tomato at high S0 might be lower than the values estimated in the present experiment. Results showed that initial suc concentration affected the relative contribution of photosynthesis on their carbon balances and that the responses were species specific. The failure of validation at S0 in a range specific to each species suggested the need for further study on carbon metabolism of in vitro plantlets cultured with sugar in the medium.
The Development of a Genetic Database to Identify Olive Cultivars
Authors: Guerin Jenny R. , Sweeney Susan M. , Collins Graham G. , Sedgley Margaret
Published: January 2019

The National Olive Variety Assessment (NOVA) collection, established at the Roseworthy Campus of the University of Adelaide, contains six replicate trees of 100 olive (Olea europaea L.) accessions grown in the same environment. The DNA fingerprints of these accessions were compared, using randomly amplified polymorphic DNA (RAPD), to those of a number of cultivars obtained from international collections. A total of 86 uniquely named accessions in the NOVA collection resulted in 58 different genotypes. Different names were synonyms for the same genotype, and homonyms were also found where accessions with the same name had different DNA fingerprints. A rapid and efficient protocol was developed to identify unknown olive genotypes using a two-stage process. Data from DNA fingerprints were added to a matrix already containing binary data from recognized standard cultivars. The estimated probability of any given RAPD profile randomly occurring at this stage ranged between 6 × 10-4 and 2 × 10-8. In the second stage, the approximate identity of the unknown genotype, revealed by the resulting dendrogram, was confirmed by comparing it with appropriate standards under identical conditions of DNA amplification and band separation. The data collected in this report form the basis of a genetic database that can be used for the identification of olive samples.