bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship Between Nitrogen Fertilization and Cercospora Leaf Spot and Alternaria Leaf Blight of Carrot
Authors: Westerveld Sean M. , McKeown Alan W. , McDonald Mary Ruth
Published: February 2019

Alternaria leaf blight (ALB) and Cercospora leaf spot (CLS) are economically important diseases of carrot in Ontario. Field experiments were conducted in the Holland Marsh, Ontario, to determine the effect of nitrogen (N) application rates on both diseases. Five rates of N were applied to organic and mineral soils in which two carrot cultivars, Idaho and Fontana, were grown in each of 2002, 2003, and 2004. Both diseases were rated every 2 weeks on a scale of 0 (healthy) to 10 (tops destroyed), and the number of live (green) leaves per plant was assessed at harvest. In addition, three N rates were applied to carrot plants grown in the greenhouse, and the plants were inoculated with Alternaria dauci (Kühn) Groves and Skolko. Disease severity, senescence, and sap nitrate-N concentration were assessed. In the field trials, the response of ALB and CLS to N application rate was relatively consistent across cultivar, soil type, and year. Area-under-the-disease-progress curves typically increased with decreasing N rate for both diseases. In lower N treatments, this resulted in fewer live leaves per plant at harvest. In the greenhouse, ALB severity increased with increasing amount of leaf senescence at final assessment. The results suggest that N application rate could be used to reduce the need for fungicide applications to control these diseases in the field.
Vegetative Propagation of Five Northern Forest Understory Plant Species from Either Rhizome or Stem Sections
Authors: Nivot Nathalie , Olivier Alain , Lapointe Line
Published: February 2019

Five understory plants, Asarum canadense L., Caulophyllum thalictroides (L.) Michx., Sanguinaria canadensis L., Trillium grandiflorum (Michx.) Salisb., of the Northeastern hardwood forests, and Oplopanax horridus (Sm.) Miq., of Western North American temperate forests, are of particular interest for horticultural and natural medicinal products industries. A rapid and efficient propagation method was needed to reproduce these plants vegetatively. To achieve this, the effect of 1000 mg·L−1 (for herbaceous species) or 3000 mg·L−1 (for O. horridus) auxin (IBA) and/or cytokinin (kinetin) on the growth of rhizome (for A. canadense, C. thalictroides, S. canadensis, T. grandiflorum) or stem sections (for O. horridus) was investigated. Nontreated controls were included for each species and an additional control with an intact apical bud was included for A. canadense, S. canadensis, and T. grandiflorum. No vegetative propagation was obtained for T. grandiflorum. Survival of O. horridus and C. thalictroides propagating units was 60% to 80% and 90% to 100%, respectively, and both rooted well even in absence of growth regulators. Asarum canadense produced two times and S. canadensis three to four times more roots when treated with the IBA + kinetin or the IBA treatment, respectively, compared with the control rhizome sections without an apical bud. For these two species, the presence of an apical bud enhanced survival and/or shoot emergence and those rhizome sections produced on average more biomass than the other treatments. Our results showed that either rhizome or stem sections can provide an efficient method to propagate A. canadense, C. thalictroides, O. horridus, and S. canadensis and thus reduce pressure on wild populations.
Carrot Seed Germination at High Temperature: Effect of Genotype and Association with Ethylene Production
Authors: Nascimento Warley M. , Vieira Jairo V. , Silva Giovani O. , Reitsma Kathleen R. , Cantliffe Daniel J.
Published: February 2019

Carrot (Daucus carota L.) seed germination may be erratic or reduced under high temperatures (above 35 °C). Even in tropical genotypes (tolerant to high temperatures during crop development), the negative effects of high temperatures on carrot stand establishment have been observed, especially during summer. The objectives of this study were to characterize commercial carrot cultivars and accession lines for their ability to germinate at high temperature and determine the ethylene production during imbibition at high temperature. Seeds from 34 commercial cultivars and 125 carrot accessions from the North Central Regional Plant Introduction Station were germinated at 25 °C (optimal) and 35 ± 0.5 °C (high) in constant light. Ethylene production during seed imbibition at high temperature was evaluated in some genotypes. Many of the commercial cultivars had reduced germination at 35 °C. ‘XPC-3617’, ‘Alvorada’, ‘Brasilia’, and ‘Esplanada’ had the greatest germination at 35 °C. A greater number of accessions germinated at 35 °C than did the commercial genotypes. The accession PI 319858 germinated 95% at both temperatures and was considered thermotolerant. Six accessions (Ames 7665, Ames 7698, Ames 25031, PI 167082, PI 294637, and PI 319858) germinated above 80% at 35 °C and were also identified as potential sources of thermotolerance. Fifteen other accessions (Ames 7694, Ames 25031, Ames 25036, Ames 25049, Ames 25705, PI 167082, PI 179687, PI 180834, PI 261782, PI 269486, PI 273658, PI 277710, PI 288242, PI 294637, and PI 319858) had thermotolerance ratios of T35/T25 0.85 or greater (where T35 = germination at 35 °C and T25 = germination at 25 °C) and were identified for further testing. The identified thermotolerant genotypes might be useful for carrot seed germination mechanism studies as well as for breeding programs. Ethylene production during seed germination at high temperature was greater in thermotolerant genotypes than in thermosensitive genotypes. High correlations were observed between first germination count at 35 °C and ethylene production, total germination at 35 °C and ethylene production, and thermotolerance ratio and ethylene production.
Controlled Deterioration and Accelerated Aging Tests to Estimate the Relative Storage Potential of Cucurbit Seed Lots
Authors: Demir Ibrahim , Mavi Kazim
Published: February 2019

The laboratory germination (radicle emergence) percentages of 9 watermelon, 12 melon, and 7 cucumber seed lots were tested after storing in relatively adverse storage conditions of 25 °C and 12% mc for 6, 12, and 18 months in sealed aluminum foil packets. The laboratory germination (radicle emergence) of lots was determined after controlled deterioration (CD) at 45 °C with 20% or 24% moisture content (mc) for 48, 72, 96, 120, and 144 h. The accelerated aging test (AA) was conducted at 45 °C for the same aging periods. A number of seed lots was dead by 12 and 18 months in watermelon and cucumber, respectively. Various combinations of test regimens were found to be correlated with laboratory germination after 6 months storage, but the most consistent regimens for AA tests was 96 h at 45 °C in all species (r = 0.71 to 0.98). In the CD tests, 72 h with 20% mc at 45 °C gave the best correlation (r = 0.86 to 0.96). These conditions of highest correlation were observed after laboratory germination after 6 months storage and are suggested as good predictors of storage life in cucurbit seed lots. The initial standard germination before storage was also significantly correlated with seed longevity, but the correlation coefficient was generally lower (r = 0.60 to 0.83) than the AA and CD test results and separation of lots less clear.
Influence of Nitrogen and Potassium Fertilization on Fruiting and Capsaicin Content in Habanero Pepper (Capsicum chinense Jacq.)
Authors: Medina-Lara Fátima , Echevarría-Machado Ileana , Pacheco-Arjona Ramón , Ruiz-Lau Nancy , Guzmán-Antonio Adolfo , Martinez-Estevez Manuel
Published: February 2019

Habanero pepper (Capsicum chinense Jacq.) is a very important crop in Mexico and demand for it is increasing in national and international markets. The habanero pepper produced on the Yucatan Peninsula is considered of superior quality to that grown in the rest of the world as a result of its shelf life and pungency. Despite its importance, little research has been done on cultivation conditions that may affect its productivity and fruit quality. The effect of N or K fertilization on habanero pepper development and fruit pungency was evaluated. Plants under fertilization stress (control) had high capsaicin content. Nitrogen fertilization significantly increased plant growth and fruit while maintaining high capsaicin levels. Optimum response was produced with 15 mm urea as the N source. Potassium fertilization had no positive effects on growth or productivity. The N treatments modified endogenous K levels in the pepper plants and vice versa. The K : N ratio (specifically in leaves and roots) varied between treatments with values greater than 1 in the K treatments, near 0.5 in the control, and less than 0.5 in the N treatments. This parameter may be an important indicator of habanero pepper productivity and requires study under different fertilization regimes.
Rate of Nitrogen Application During the Growing Season and Spraying Plants with Urea in the Autumn Alters Uptake of Other Nutrients by Deciduous and Evergreen Container-grown Rhododendron Cultivars
Authors: Scagel Carolyn F. , Bi Guihong , Fuchigami Leslie H. , Regan Richard P.
Published: February 2019

The influence of fall sprays with urea on the uptake of nutrients other than nitrogen (N) was assessed using 1-year-old container-grown Rhododendron L. (Rhododendron ‘H-1 P.J.M’) and azalea (Rhododendron ‘Cannon's Double’) grown with different rates of N. Plants were grown with a complete fertilizer containing different N rates from May to Sept. 2004 sprayed or not with urea in the fall of 2004 and grown with a complete fertilizer containing different N rates in the spring of 2005. Urea sprays altered uptake of nutrients other than just N although fertilizer application with other nutrients ceased before plants were sprayed with urea. Across a wide range of plant sizes and N status, urea sprays increased net phosphorus (P), copper (Cu), and manganese (Mn) uptake and decreased net potassium (K) and magnesium (Mg) uptake during the year of urea application. Spraying plants with urea altered nutrient demand and storage in different plant structures during the winter. For azalea, urea sprays increased P demand by roots, Mn demand by 2004 stems, and Cu demand by stems. Urea also decreased storage of K in roots and 2004 stems of azalea and Mg in roots. For rhododendron, urea sprays increased P demand by 2003 stems and 2004 leaves and Mn demand by 2004 leaves. Urea sprays also decreased storage of K and Mg in 2004 leaves of rhododendron. For both cultivars, urea sprays increased mobilization of iron (Fe) from storage and demand for Fe in stems. Spraying Rhododendron with urea in the fall altered uptake and demand for certain nutrients during the following spring. Urea sprays in the fall of 2004 increased uptake and possibly demand for P, K, and sulfur during the spring of 2005 for both cultivars, the uptake of calcium by rhododendron, and the uptake of Mg and Mn by azalea. Our results indicate that when growers spray plants with urea in the fall, spring fertilizer practices may need to be modified to account for increased uptake or demand of certain nutrients.
Annual Water Status, Development, and Flowering Patterns for Rosmarinus officinalis Plants Under Different Irrigation Conditions
Authors: Nicolás Emilio , Ferrandez Trinitario , Rubio José Salvador , Alarcón Juan José , Sánchez-Blanco Ma Jesús
Published: February 2019

The annual water status and phenological patterns of Rosmarinus officinalis plants in relation to irrigation were studied to improve the use of this species in gardening conditions. Rosmarinus officinalis seedlings were pot-grown for 4 months in the nursery. After this period, plants were transplanted to field conditions before three irrigation treatments were applied from Nov. 2000 to Dec. 2001 (control and deficit treatments: C, T-1 and T-2, respectively). The total amount of water applied by irrigation during the experimental period was 167 mm for control, 83.5 mm for T1 (50% of the control), and 50 mm for T-2 (30% to the control). Two main periods of vegetative growth (beginning of spring and fall) were observed in all treatments. At the end of the experimental period, deficit irrigation had altered the morphology of the R. officinalis plants, reducing plant height and shoot growth. Maximum flowering intensity occurred at the beginning of fall for all irrigation treatments. Deficit irrigation treatments induced a more intense flowering density, although of lower longevity than control plants. The annual pattern of shoot water potential at predawn reflected the irrigation regimes, although less difference resulting from irrigation effect was detected in this parameter at midday. Plants under deficit irrigation showed a conservative strategy in the use of water, reducing stomatal conductance. This finding may be of use for the successful gardening of Rosmarinus officinalis plants in semiarid conditions.
‘Miaoli No. 1’ Mulberry: A New Cultivar for Berry Production
Authors: Chang Jer-Chia
Published: February 2019

‘Miaoli No. 1’ mulberry (Morus atropurpurea Roxb., a synonym of Morus alba L.) has recently been released by the Miaoli District Agricultural Research and Extension Station (MDARES) in Miaoli, Taiwan. ‘Miaoli No. 1’ is a promising cultivar that produces a high yield of large fruit suitable for both processing and fresh markets. ‘Miaoli No. 1’ is named for the first commercial release of mulberry cultivars specifically for berry production from MDARES.
The Isolation of Antioxidant Enzymes from Mature Tomato (cv. Micro-Tom) Plants
Authors: Gratão Priscila L. , Monteiro Carolina C. , Peres Lázaro E.P. , Azevedo Ricardo Antunes
Published: February 2019

The activity of catalase (CAT), guaiacol peroxidase (GPOX), ascorbate peroxidase (APX), glutathione reductase (GR), and the isoenzymes of superoxide dismutase (SOD) were determined in the organs of tomato (Lycopersicon esculentum) cultivar Micro-Tom after 104 days of development. The total activities of CAT, GPOX, and GR were higher in the stem than in others tissues, whereas the stem exhibited the lowest APX activity. Activity staining analysis following gel electrophoresis revealed the existence of four SOD isoenzymes in leaves, three in fruits, but only two in the roots and stems. This characterization is essential for an investigation into the effect of abiotic and biotic stresses on the oxidative stress responses by this plant model system.
Strawberry Species of Iturup and Sakhalin Islands
Authors: Hummer Kim E. , Sabitov Andrey
Published: February 2019

A plant-collecting expedition to Iturup and Sakhalin Islands, Sakhalin Territory, Russian Federation, occurred between 21 July and 12 Sept. 2003. Strawberries, Fragaria L., were observed and collected. Japanese and Russian flora describe two diploid (2n = 2x = 14) species, F. iinumae Makino and the Yezoensis strawberry, F. nipponica Makino [syn. = Fragaria nipponica var. yezoensis (H. Hara) Kitam.], as native to those islands. In addition, a recent monograph described a new octoploid (2n = 8x = 56) strawberry species, F. iturupensis Staudt, from a Japanese herbarium specimen collected on Atsunupuri volcano near Lesozovodoskyi, Iturup, in 1929. The objectives of the 2003 collecting trip were to obtain wild strawberries from these islands and determine if a population of F. iturupensis still existed on the volcano. The native F. iinumae Makino was obtained from the Ogonki Village, Anivskyi Region, Southern Sakhalin Island, but was not observed on Iturup. The Yezoensis strawberry was observed at Cape Otlivnoy, Iturup. Two small colonies of the native octoploid F. iturupensis Staudt were collected from mid-elevations on the east-facing slope of Atsunupuri volcano. The native distribution of F. iturupensis was limited to this volcanic montane habitat and was not found in the foggy, sandy locations of coastal elevations on Iturup. The leaf morphology and growth habit of F. iturupensis plants were similar to that of F. virginiana subsp. glauca (S. Watson) Staudt of North America, but the fruit was different, more like F. vesca L. Probable cultivated escapes were observed at two sites on the east coast of Iturup and at one site in southern Sakhalin. The 2003 expedition confirmed the existence of F. iturupensis, the only known native Asian octoploid strawberry on Atsunupuri. Limited quantities of germplasm are available for research from the curator, U.S. Department of Agriculture, Agricultural Research Service, National Clonal Germplasm Repository, Corvallis, OR, the U.S. national strawberry gene bank.
Primocane-fruiting Raspberry Production
Authors: Pritts Marvin
Published: February 2019

Primocane-fruiting raspberries (Rubus idaeus L.) have the capacity to fruit in the fall and again the next summer. Because of their low chilling requirement, this type is used to produce a double crop in warmer regions of the world. However, many growers prune canes to the ground after the fall crop, sacrificing the summer crop for a single, large fall crop. This practice is less labor-intensive than the selective cane removal required for double-cropping and crop quality is often higher. Primocane-fruiting raspberries also are easily manipulated to extend the season. Early- and late-fruiting cultivars, cultural manipulations, rowcovers, high tunnels, and greenhouses are all used commercially to extend the season of primocane raspberries year-round. This is beneficial for consumers because high-quality fruit is now available for a much longer period than was possible in the past.
Grafting Effects on Vegetable Quality
Authors: Davis Angela R. , Perkins-Veazie Penelope , Hassell Richard , Levi Amnon , King Stephen R. , Zhang Xingping
Published: February 2019

Vegetable grafting began in the 1920s using resistant rootstock to control soilborne diseases. This process is now common in Asia, parts of Europe, and the Middle East. In Japan and Korea, most of the cucurbits and tomatoes (Lycopersicon esculentum Mill.) grown are grafted. This practice is rare in the United States, and there have been few experiments to determine optimal grafting production practices for different geographical and climatic regions in America. This is beginning to change as a result of the phase out of methyl bromide. The U.S. cucurbit and tomato industries are evaluating grafting as a viable option for disease control. Because reports indicate that type of rootstock alters yield and quality attributes of the scion fruit, some seed companies are investigating grafting as a means to improve quality. It has been reported that pH, flavor, sugar, color, carotenoid content, and texture can be affected by grafting and the type of rootstock used. Reports vary on whether grafting effects are advantageous or deleterious, but it is usually agreed that the rootstock/scion combination must be carefully chosen for optimal fruit quality. Additionally, it is important to study rootstock/scion combinations under multiple climatic and geographic conditions because many rootstocks have optimal temperature and moisture ranges. This report gives an overview of the effect of grafting on vegetable quality.
Grafting for Disease Resistance
Authors: King Stephen R. , Davis Angela R. , Liu Wenge , Levi Amnon
Published: February 2019

The primary purpose of grafting vegetables worldwide has been to provide resistance to soilborne diseases. The potential loss of methyl bromide as a soil fumigant combined with pathogen resistance to commonly used pesticides will make resistance to soilborne pathogens even more important in the future. The major disease problems addressed by grafting include fusarium wilt, bacterial wilt, verticillium wilt, monosporascus root rot, and nematodes. Grafting has also been shown in some instances to increase tolerance to foliar fungal diseases, viruses, and insects. If the area devoted to grafting increases in the future, there will likely be a shift in the soil microbial environment that could lead to the development of new diseases or changes in the pathogen population of current diseases. This shift in pathogen populations could lead to the development of new diseases or the re-emergence of previously controlled diseases. Although grafting has been demonstrated to control many common diseases, the ultimate success will likely depend on how well we monitor for changes in pathogen populations and other unexpected consequences.
Developing Seed-propagated Lowbush Blueberry Families
Authors: Jamieson Andrew Raymond
Published: February 2019

The benefits of lowbush blueberry seedlings over clonally propagated plants, in terms of improved plant performance and low cost per plant, led to the establishment of a trial of 42 seedling families in 1990. The purpose of this trial was to identify hybrid seed that produces plants that are high yielding and of good fruit quality. Considering berry yield and quality, seedling families KBF-7, KBF-10, KBF-13, and KBF-42 were identified as top performers. All of these have ‘Fundy’ as one parent. KBF-7 is well suited to producing blueberries for marketing as high-quality fresh fruit. KBF-10 spreads well by rhizomes and may be suited as fill-in plants for bare areas in commercial lowbush blueberry fields.
Evaluation of Oxalate Concentration in the U.S. Spinach Germplasm Collection
Authors: Mou Beiquan
Published: February 2019

The entire USDA spinach (Spinacia oleracea) germplasm collection (338 accessions) and 11 commercial cultivars were screened for oxalate concentration. There were significant differences in oxalate concentration among the genotypes evaluated, ranging from 5.3% to 11.6% on a dry weight basis. The low-oxalate genotypes identified in our experiments are all S. oleracea. None of the two S. tetrandra and four S. turkestanica accessions screened had low levels of oxalate. Two accessions from Syria, PI 445782 (cultivar name Shami) and PI 445784 (cultivar name Baladi), consistently had low oxalate concentration. When expressed on a fresh weight basis, oxalate concentration may be affected by the moisture content of the plant. Oxalate concentration had little correlation with leaf types (flat or savoy) and leaf weight per plant. With the genetic variation and sources of low oxalate concentration found, breeding of spinach for a low level of oxalate seems feasible.
Breeding for Increased Tolerance to Black Root Rot in Strawberry
Authors: Particka Chrislyn Ann , Hancock James F.
Published: February 2019

Black root rot (BRR) is a widespread disease of strawberry (Fragaria ×ananassa) that causes the death of feeder roots and the degradation of structural roots resulting in an overall decrease in productivity. Black root rot is primarily caused by Rhizoctonia fragariae Husain and W.E. McKeen, Pythium Pringsh., and Pratylenchus penetrans (Cobb) Filipjev and Schuurmans Stekhoven. A previous study identified varying levels of tolerance to BRR in strawberry cultivars with some having high levels of tolerance. In this study, progeny populations were created to determine the amount of genetic variability for BRR tolerance. Genotypes with high, intermediate, and low tolerance to BRR were crossed in a diallel mating scheme, progeny were planted in Vapam (metam sodium)-fumigated and nonfumigated soil, and were analyzed for yield parameters. The results showed significant differences for both treatment and family, but not for the interaction between treatment and family. Pathogen analysis indicated presence of fungal pathogens and nematodes in both fumigated and nonfumigated soil.
Comparative Nutrient Element and Antioxidant Characterization of Berry Fruit Species and Cultivars Grown in Hungary
Authors: Hegedűs Attila , Balogh Emőke , Engel Rita , Sipos Béla Zoltan , Papp János , Blázovics Anna , Stefanovits-Bányai Éva
Published: February 2019

Fruits of four berry species (strawberry, raspberry, red and black currants) were compared in their elemental composition (Al, B, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn) and redox parameters involving total phenol content (TPC), ferric reducing ability (FRAP), 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, and total radical scavenger activity (TRSA). Berry cultivars contained significantly higher (P ≤ 0.05) amounts of most detected elements as compared with apple with many maximum elemental values demonstrated by the black currant ‘Otelo’. Black currant also had the greatest antioxidant capacity as demonstrated through all conducted assays. The results obtained through FRAP, TPC, and TRSA assays were closely correlated, whereas TRSA and DPPH varied independently. Our study provides valuable information on the antioxidant capacity of several berry species grown in Hungary and highlights the crucial influence of cultivar on elemental content and antioxidant power of berry fruits. This study demonstrated the ability to select berry cultivars for specific nutritional purposes or assign parental lines in functional breeding programs.
Leafminer Resistance in Spinach
Authors: Mou Beiquan
Published: February 2019

Leafminer (Liriomyza spp.) is a major insect pest of many important agricultural crops, including spinach (Spinacia oleracea). Genetic variability in leafminer resistance has not been studied for spinach. The purposes of the present experiments were to evaluate differences in leafminer damage among spinach genotypes, to compare results obtained from insect cage and field experiments, and to study the association among different resistant traits. We screened 345 accessions of the U.S. spinach collection for leafminer resistance in an outdoor insect cage and putative resistant genotypes were further tested in the cage and in the field over 2 years. Although no genotype was immune to leafminers, significant genotypic differences were found for leafminer stings per unit leaf area, mines per plant, and mines per 100 g plant weight. PI 274065 had the lowest sting density, whereas PI 174385 showed the fewest mines per unit plant weight among genotypes in the field. Rank order of stings per square centimeter leaf area did not significantly change for the genotypes in the cage and field tests, and the sting results from different tests were also highly correlated, suggesting that a cage test could be used to screen germplasm for fewer leafminer stings, and sting density is a reliable trait for the selection of leafminer feeding nonpreference. Stings per unit leaf area were not correlated with mines per plant or per 100 g plant weight, which suggests that feeding nonpreference does not necessarily mean oviposition–nonpreference for a spinach genotype and these two traits can be improved independently. Stings per square centimeter leaf and mines per 100 g plant weight had little correlation with plant weight in cage and field tests, suggesting that leafminer sting and mine densities are not associated with plant biomass, and it is possible to improve and combine the leafminer resistance and yield traits in a spinach cultivar. From these findings, the genetic improvement of spinach for leafminer resistance seems feasible.
Field Evaluation of 64 Rootstocks for Growth and Yield of ‘Kensington Pride’ Mango
Authors: Smith Malcolm W. , Bright Jeremy D. , Hoult Mark D. , Renfree Richard A. , Maddern Tony , Coombes Neil
Published: February 2019

Despite an abundance of polyembryonic genotypes and the need for rootstocks that improve scion yield and productivity, simultaneous field testing of a wide range of mango (Mangifera indica L.) genotypes as rootstocks has not previously been reported. In this experiment, we examined the growth and yield of ‘Kensington Pride’ on 64 mango genotypes of diverse origin during the first four seasons of fruit production to identify those worth longer-term assessment. We also recorded morphological characteristics of seedlings of 46 of these genotypes in an attempt to relate these measures to subsequent field performance. Tree canopy development on the most vigorous rootstocks was almost double that on the least vigorous. Growth rates differed by more than 160%. Cumulative marketable yield ranged from 36 kg/tree for the lowest yielding rootstock to 181 kg/tree for the most productive. Yield efficiency also differed markedly among the 64 rootstocks with the best treatment being 3.5 times more efficient than the poorest treatment. No relationship was found between yield efficiency and tree size, suggesting it is possible to select highly efficient rootstocks of differing vigor. Two genotypes (‘Brodie’ and ‘MYP’) stood out as providing high yield efficiency with small tree size. A further two genotypes (‘B’ and ‘Watertank’) were identified as offering high yield efficiency and large tree size and should provide high early yields at traditional tree spacing. Efforts to relate the morphology of different genotype seedlings to subsequent performance as a rootstock showed that nursery performance of mango seedlings is no indication of their likely behavior as a rootstock. The economic cost of poor yields and low yield efficiencies during the early years of commercial orchard production provide a rationale for culling many of the rootstock treatments in this experiment and concentrating future assessment on the top ≈20% of the 64 treatments. Of these, ‘MYP’, ‘B’, ‘Watertank’, ‘Manzano’, and ‘Pancho’ currently show the most promise.
Early-season Air Temperature Affects Phenolic Production in ‘Early Black’ Cranberry Fruit
Authors: Vanden Heuvel Justine E. , Autio Wesley R.
Published: February 2019

Anecdotal information has linked cool air temperatures before harvest with increased phenolic production in cranberry; however, there is little information available on the effect of temperature on phenolic production in cranberry fruit. The objective of this study was to determine the effect of air temperature throughout the growing season on the concentration of total anthocyanins, total flavonols, and total phenolics at harvest in fruit from seven ‘Early Black’ bogs in southeastern Massachusetts. Contrary to the anecdotal information available, correlations of temperature to fruit composition indicated that warmer temperatures early in the season (around bloom and fruit set) had the most positive impact on total anthocyanins and total flavonols. Total phenolic concentration in the harvested fruit was impacted by air temperature in the preharvest period; however, that relationship was positive.
Significance of Flower Bud Density for Cultivar Evaluation in Almond
Authors: Kodad Ossama , Socias i Company Rafel
Published: February 2019

Flower bud density, spur density, and number of flower buds per spur were evaluated in 57 almond cultivars and selections during 3 consecutive years to establish their repeatability as well as their potential to ensure a sustainable commercial production. These three traits showed a high variability with significant differences between genotypes and years as well as a significant interaction of genotype and year. The effect of location and the interaction of location and genotype were not significant for bud density, but they were for spur density and number of flower buds per spur. Variability of flower bud density is mostly related to the number of flower buds per spur as indicated by the higher repeatability of spur density than that of the other two traits. A high flower bud density is essential for a sustainable production, because a high number of flowers may compensate frost damage. Early selection for a high flower bud density can be done indirectly through selection for a high spur density but requires its evaluation over several years.
Modeling Growth of Matthiola incana in Response to Saline Wastewaters Differing in Nitrogen Level
Authors: Grieve Catherine M. , Poss James A. , Shouse Peter J. , Carter Christy T.
Published: February 2019

The capture and reuse of nutrient-rich greenhouse effluents may be an environmentally sound option for floriculture production, which would conserve fresh water resources and reduce off-site pollution of surface and groundwaters. This study was initiated in 24 outdoor lysimeters to determine effects of salinity and varying concentrations of nitrogen on the growth, yield, and ion relations of stock [Matthiola incana (L.) R. Br.] cultivar Cheerful White. The experiment was a 4 × 4 factorial, partially replicated design with four irrigation water salinities (2, 5, 8, and 11 dS·m−1) and four nitrate concentrations (2.5, 3.6, 5.4, and 7.1 mmol·L−1; N = 35, 50, 75, and 100 ppm). Ammonium nitrogen was included in the nutrient solutions. Stem lengths were measured three times weekly. Measurements at final harvest were stem and inflorescence lengths, stem and floret diameters, number of axillary buds and florets, and shoot and root fresh weights. Time course of stem elongation was quantified as a function of thermal time with a phasic growth model. Salinity significantly delayed initiation of the exponential growth phase, shortened its duration, and reduced the rate of plant development. The overall effect was to delay time to harvest of marketable stems. Although length of the flowering stems decreased with increasing salinity, marketable stems (≈60 cm) were produced in all treatments. Mineral ion relations in the plant tissues were influenced significantly, but independently, by both salinity and nitrogen. Leaf sodium, magnesium, and chlorine concentrations increased with increasing salinity; calcium and potassium decreased. In response to increasing external nitrogen, both potassium and chlorine decreased; sodium increased, whereas calcium and magnesium were unaffected. We conclude that in closed-loop irrigation systems, the nitrogen requirements for stock are low and that growers could minimize costs and limit off-site pollution by reducing nitrogen inputs.
Regional Analysis of Production Practices and Technology Use in the U.S. Nursery Industry
Authors: Hodges Alan W. , Hall Charles R. , Behe Bridget K. , Dennis Jennifer H.
Published: February 2019

The National Nursery Survey has been conducted four times at 5-year intervals (1988, 1993, 1998, and 2003) by a multistate research committee on economics and marketing to help fill the void of publicly available information on management characteristics of the nursery industry. For the first time in 2003, the National Nursery Survey was conducted using a standard sampling methodology with 15,588 total firms representing 44 states. The objective of this study was to provide a regional analysis of nursery production practices, because production practices and technology use may differ across regions in response to varying economic and environmental conditions. From analysis of the 2485 returned surveys, firms in the northern and interior regions of the country with more seasonal activity made greater use of temporary labor. Containerized growing systems were the predominant system throughout the United States; however, firms in the Southeast, South Central, and Pacific coast regions used this system to a greater degree, whereas firms in other regions also commonly used bare root and balled and burlapped systems. Nurseries in the Southeast region, with a warmer climate, used Integrated Pest Management practices more prevalently. Most regions had a significant share of total production from native American plants, approaching or exceeding 20% of total sales, except the Pacific region. In some regions, forward-contracting accounted for a significantly higher share of total sales, perhaps indicating greater aversion to market risk. The Mountain region stood out for its high level of adoption of computer technologies for production, marketing, and management. Data on water use and irrigation technology did not indicate any clear pattern with respect to regional differences in relation to water scarcity.
Role of Crop Load in Chloroplast Ultra-structure and Zonal Chlorosis, a Physiological Disorder in ‘Honeycrisp’ Apple Trees
Authors: Snyder-Leiby Teresa Eileen , Wang Shixiong
Published: February 2019

‘Honeycrisp’ is a relatively new apple cultivar (Malus ×domestica Borkh.) with a unique crisp fruit texture that makes it highly desirable. However, the leaves often develop a zonal chlorosis that resembles potato leafhopper damage. Other researchers have determined that the symptoms correlate with decreasing crop load rather than leafhopper damage. This study investigates the possibility that the zonal chlorosis is related to the buildup of starch grains causing rupture of chloroplasts. Transmission electron microscopy was used to document ultrastructural changes in chloroplasts in trees with three different crop loads from the beginning of the season to the end of the season. In trees with extremely low crop loads, we observed abnormalities of chloroplast membrane structure and accumulation of larger and more numerous starch grains. These appear before the appearance of chlorotic symptoms. By early August, the chloroplasts from chlorotic regions of leaves on trees with light crop loads are completely disrupted and abnormally large starch grains are found in place of chloroplasts. As the season progresses, trees with moderate and heavy crop loads showed less severe chloroplast disruption and smaller starch grain accumulation than trees with light crop load.
Nematode Control from Shank- and Drip-applied Fumigant Alternatives to Methyl Bromide
Authors: Schneider Sally M. , Ajwa Husein A. , Trout Thomas J. , Gao Suduan
Published: February 2019

Field studies were conducted to evaluate potential alternatives to methyl bromide (MBr) for the control of plant parasitic nematodes in shallow-rooted, bedded cropping systems such as strawberry and in perennial nursery cropping systems in central California. Chloropicrin (Pic), 1,3-dichloropropene (1,3-D or Telone), combinations of 1,3-D + Pic, iodomethane (IM) + Pic, propargyl bromide (PBr), and metam sodium (MS) were compared with untreated controls and industry standard MBr/Pic treatments. Materials were applied by both shank-injection and drip-application, except MS and PBr, which were applied only by drip. The efficacy on citrus nematode (Tylenchulus semipenetrans Cobb) and/or root-knot nematode (Meloidogyne spp. Chitwood) control was investigated in three trials conducted on soils ranging from sandy loam to silty clay loam. All treatments controlled nematodes near the injection point (center of bed and moderate depths) comparable to MBr/Pic. Drip-applied Pic provided somewhat less control than MBr/Pic at the shoulder of the bed when delivered in 25 mm of water and MS provided no control at the bed shoulder. IM + Pic, both shank-injected and drip-applied, provided nematode control to a depth of 150 cm comparable to MBr/Pic. Telone EC applied to a dry field in 75 mm water did not control nematodes well at either 90- or 150-cm depths, whereas PBr controlled nematodes as effectively as MBr/Pic at the 90-cm depth, but not at the 150-cm depth. Propargyl bromide at 67 kg·ha−1 was effective at killing the nematodes up to 30 cm deep in a strawberry plant bed. The dosage exposure values (within 96 h after fumigation) observed for greater than 99% control of nematodes were much lower for PBr (≈1 mg·L−1·h) than those for 1,3-D + Pic (17 mg·L−1·h when applied at 61:35 1,3-D:Pic mass ratio), Pic alone (10 mg·L−1·h), and IM + Pic (19 mg·L−1·h when applied at 50:50 mass ratio). Drip application technology showed promise for effective alternatives to MBr/Pic. Consistent delivery of an effective dosage of a material throughout the target soil profile is necessary for consideration as an acceptable alternative to MBr for high-value crops.
Characterization of Phytophthora Species from Leaves of Nursery Woody Ornamentals in Tennessee
Authors: Donahoo Ryan S. , Lamour Kurt H.
Published: February 2019

Species of Phytophthora are ubiquitous in ornamental production resulting in significant crop losses. In Tennessee, national surveys for the sudden oak death pathogen Phytophthora ramorum in 2004 and 2005 led to the isolation of Phytophthora species causing disease in nursery-grown or handled woody ornamentals or both. Isolates recovered were identified to species using direct sequencing of the internal transcribed spacer and examination of morphological characters. Six known species (P. cactorum, P. citricola, P. citrophthora, P. nicotianae, P. palmivora, P. tropicalis) and one newly described species (P. foliorum) were recovered from ericaceous hosts. The most common species recovered were P. citricola and P. citrophthora. Genetic analysis using amplified fragment length polymorphism (AFLP) markers revealed intraspecific genotypic diversity as well as isolates with identical AFLP genotypes from multiple locations across multiple years. This work provides evidence for species and genotypic diversity of Phytophthora recovered in Tennessee as well as insight into the movement of individual genotypes in woody ornamental production.
Heat Level in Chile Pepper in Relation to Root and Fruit Infection by Phytophthora capsici
Authors: Tahboub Mohammed B. , Sanogo Soumaila , Bosland Paul W. , Murray Leigh
Published: February 2019

Phytophthora blight, caused by Phytophthora capsici Leon., is a major plant disease that limits chile pepper (Capsicum annuum L.) production in New Mexico. Chile pepper producers in New Mexico report that Phytophthora blight symptoms appear to develop slower and its incidence is lower in hot than in nonhot chile pepper cultivars. There has been no previous systematic assessment of the relationship of chile pepper heat level to chile pepper response to P. capsici. Three hot (‘TAM-Jalapeño’, ‘Cayenne’, and ‘XX-Hot’) and two low-heat (‘NuMex Joe E. Parker’ and ‘New Mexico 6-4’) chile pepper cultivars were inoculated at the six- to eight-leaf stage with zoospores of P. capsici under greenhouse conditions. Additionally, detached mature green fruit from three hot (‘TAM-Jalapeño’, ‘Cayenne’, and ‘XX-Hot’) and one low-heat (‘AZ-20’) chile pepper cultivars were inoculated with mycelium plugs of P. capsici under laboratory conditions. When plant roots were inoculated, Phytophthora blight was slowest to develop on ‘TAM-Jalapeño’ in contrast to all other cultivars. All ‘TAM-Jalapeño’ plants showed wilting symptoms or were dead ≈22 days after inoculation compared with 18, 15, 14, and 11 days for ‘NuMex Joe E. Parker’, ‘New Mexico 6-4’, ‘XX-Hot’, and ‘Cayenne’, respectively. When fruit were inoculated, lesion length ratio was significantly higher for ‘TAM-Jalapeño’ fruit than for ‘Cayenne’, ‘XX-Hot’, and ‘AZ-20’ fruit. Similarly, lesion diameter ratio was higher for ‘TAM-Jalapeño’ fruit than for fruit of other cultivars. Furthermore, mycelial growth on lesion surfaces was more extensive on ‘TAM-Jalapeño’ fruit than on fruit of other cultivars. Results from this study indicate that there is little or no relationship between heat level and chile pepper root and fruit infection by P. capsici.
Preharvest Application of Phellodendron Bark Extracts Controls Brown Rot and Maintains Quality of Peento-shaped Peach
Authors: Feng Xiaoyuan , Wang Baogang , Li Wensheng , Shi Lei , Cao Jiankang , Jiang Weibo
Published: February 2019

Preharvest application of Phellodendron bark (Phellodendron chinese Schneid) extract (PBE) on brown rot and postharvest quality of peach [Prunus persica (L.) Batsch var. platycarpa (Decne.) L.H. Bailey] was investigated. PBE at 0.8, 1.6, and 3.2 mg·mL−1 totally inhibited conidial germination, mycelial growth, and sporulation, respectively, of Monilinia fructicola in vitro. Preharvest PBE treatment at 21.0 mg·mL−1 at 0, 30, 60, and 90 days after full bloom controlled brown rot caused by M. fructicola on peach fruit after harvest and reduced disease incidence and lesion diameter by 37% and 61%, respectively, than those of the control 96 h after inoculation in in vivo experiments. The results from field experiments were consistent during a 3-year period. Fruit from PBE-treated trees showed higher activities of defense enzymes, including peroxidase, phenylalanine ammonia-lyase, chitinase, and β-1,3-glucanase, compared with those of the control during storage. PBE also delayed softening and loss of titratable acidity and inhibited flesh browning during storage. Total soluble solid contents were unaffected by treatment. The results indicate that preharvest application of PBE may be an alternative for controlling brown rot of peach fruit.
Sodium Chloride Effects on Growth, Morphology, and Physiology of Chrysanthemum (Chrysanthemum ×morifolium)
Authors: Lee M. Kate , van Iersel Marc W.
Published: February 2019

As a result of the decreasing availability of high-quality irrigation water, salinity tolerance of greenhouse crops is of increasing importance. Saline irrigation water can have many negative effects on plants, but also has the potential to act as a growth regulator because of its ability to reduce plant height. To determine the effects of NaCl in the irrigation water on the growth, physiology, and nutrient uptake of chrysanthemums (Chrysanthemum ×morifolium Ramat.), plants were watered with solutions with different NaCl concentrations (0, 1, 3, 6, or 9 g·L−1). Plants receiving 9 g·L−1 NaCl had a 76% reduction in shoot dry weight, a 90% reduction in stomatal conductance (g
S), and a 4-day delay in flowering compared with control plants. Chrysanthemums receiving 1 g·L−1 NaCl had a 4-cm reduction in height with only a small reduction in shoot dry weight. Stomatal conductance and transpiration were reduced by more than 60% by NaCl concentrations of 1 g·L−1 as compared with control plants. The combination of a small reduction in dry weight and a large decrease in transpiration resulted in increased water use efficiency when plants received 1 g·L−1 NaCl. Concentrations of 3 g·L−1 NaCl or higher resulted in poor-quality plants either as a result of wilting of the leaves (3 g·L−1) or severely stunted plants (6 and 9 g·L−1). Our findings indicate that chrysanthemums can be grown successfully with 1 g·L−1 NaCl in the irrigation water without negative impacts on plant quality. This has important implications for the greenhouse industry as the availability of nonsaline water decreases. Saline water may be more readily available and can have the added benefit of reduced plant height, which is an important quality characteristic for floriculture crops.
Isolation and Characterization of Nine Microsatellite Markers for Cymbidium sinense
Authors: Xia Kuaifei , Ye Xiulin , Zhang Mingyong
Published: February 2019

Microsatellite-enhanced genomic library of Cymbidium sinense was constructed using repeat-enrichment method with biotin-labeled oligos and streptavidin magnetic beads. Twenty-five microsatellite loci were isolated from a microsatellite-enhanced genomic library of Cymbidium sinense. Nine of these loci displayed genetic diversity that ranged from one to 15 alleles per locus, and the observed heterozygosity of six polymorphic loci ranged from 0.18 to 0.90 with an average of 0.47 (0.29 sd) in a sample of 30 individuals. Eight of these loci were successfully amplified in at least one of the following species: Paphiopedilum hissutissimum, P. wardii, P. armeniacum, or P. micranthum. The study provides a base for molecular breeding and assessment of germplasm resources of the Cymbidium sinense and the results suggest that the microsatellite loci developed from C. sinense may have a broad applicability within the Orchidaceae family.