bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in Gluconasturtiin Concentration in Chinese Cabbage with Increasing Cabbage Looper Density
Authors: De Villena Fernando A. , Fritz Vincent A. , Cohen Jerry D. , Hutchison William D.
Published: February 2019

Changes in the levels of gluconasturtiin (2-phenylethyl glucosinolate), an aromatic glucosinolate, was used to evaluate the response of ‘Green Rocket’ Chinese cabbage (Brassica campestris ssp. pekinensis L.) to the feeding of three and five cabbage looper (Trichoplusia ni Hübner) larvae per plant. Plants were harvested 0, 10, and 17 days after infestation. The change in gluconasturtiin concentration resulting from decreased light capture from diminished leaf area was also studied. All samples were assayed for gluconasturtiin concentration using high-performance liquid chromatography. The gluconasturtiin concentration of plants subjected to five larvae per plant showed a 59% increase 10 days after infestation compared with noninfested plants. Difference in gluconasturtiin concentration between three and five larvae per plant was nonsignificant. Seventeen days after initial infestation and 7 days after larvae were removed (final harvest), gluconasturtiin concentration did not decrease compared with the previous harvest. Reduced light or leaf area removal did not significantly affect gluconasturtiin concentration.
The Effect of Prohexadione-calcium on Fruit Set and Chemical Thinning of Apple Trees
Authors: Greene Duane W.
Published: February 2019

Prohexadione-calcium (ProCa) has emerged as one of the most important management tools that an orchardist has available to control vegetative growth and to reduce the incidence and severity of fire blight. It has also been implicated in increased fruit set on treated apple trees. This investigation was initiated to confirm the effects of ProCa on fruit set and to evaluate different thinning strategies that might be used to appropriately thin treated trees. ProCa increased fruit set when applied at petal fall at initial rates of 125 or 250 mg·L−1 in three of the four experiments described in this article. Thinners were applied before, at the time of, and after application of ProCa. In all experiments, chemical thinners did not reduce fruit set to the same crop load level on ProCa-treated trees as they did on untreated trees. It was concluded that a different and more aggressive chemical thinning strategy must be used on trees that were treated with ProCa. Fruit size was reduced on ProCa-treated trees. This reduction was usually, but not always, related to increased fruit set. ProCa increased the number of pygmy fruit on ‘Delicious’ apple trees.
A Low-cost Device for Accurate and Continuous Measurements of Fruit Diameter
Authors: Morandi Brunella , Manfrini Luigi , Zibordi Marco , Noferini Massimo , Fiori Giovanni , Grappadelli Luca Corelli
Published: February 2019

This work describes a fruit gauge based on a low-cost linear potentiometer interfaced to a data-logger, which allows continuous measurement of fruit diameter. The sensor is supported by a custom-built stainless steel frame designed to be easily applied to different size fruits. Highly significant linear relationships between tension (mV) and displacement (mm) have been found during sensor calibration. The average slope of this relationship, 5.4 × 10−3 with a standard deviation of 5 × 10−5, was used as conversion coefficient. Temperature stability was tested by submitting both the sensor and the whole gauge to a temperature range of 5–60 °C. The maximum deflection found was ±1 mV. Measurements performed during the three developmental stages of peach [Prunus persica (L), Batsch.] fruit showed high sensitivity of the gauge which allowed clear detection of diurnal patterns of fruit diameter changes and precise monitoring of minute variations in fruit growth rates during 24 h.
The Role of Ethylene in Water-deficit Stress Responses in Betula papyrifera Marsh
Authors: Gu Mengmeng , Robbins James A. , Rom Curt R.
Published: February 2019

One-year-old paper birch (Betula papyrifera Marsh.) seedlings were exposed to water deficit, ethylene, or inhibitors of ethylene action under greenhouse conditions to investigate ethylene's role in water-deficit stress-induced leaf abscission. Exposing well-watered and water-stressed paper birch to 20 ppm ethylene resulted in more than 50% leaf abscission after 96 h regardless of plant water status. However, application of a physiological level (1 ppm) of ethylene did not cause leaf abscission in either well-watered or water-stressed paper birch. Inhibitors of ethylene action (1ppm 1-methylcyclopropene or 0.1 mm silver thiosulfate) did not affect predawn water potential, gas exchange, or chlorophyll fluorescence. A significant increase in ethylene production was not detected in water-stressed paper birch before the onset of significant leaf abscission. Based on these observations, ethylene would appear to play a minor role in water-deficit stress-induced leaf abscission in paper birch.
Adjuvants Affect Penetration of Copper Through Isolated Cuticles of Citrus Leaves and Fruit
Authors: Orbović Vladimir , Achor Diann , Syvertsen James P.
Published: February 2019

Copper (Cu)-based fungicidal sprays are widely used on many crops although Cu sprays can be phytotoxic under some conditions. The mechanism of phytotoxicity is poorly understood but must involve toxic levels of Cu penetrating plant tissues. We studied the effect of different adjuvants on the deposition pattern of droplets and penetration of Cu (in Kocide fungicide) through isolated cuticles of ‘Marsh’ grapefruit leaves and ‘Valencia’ orange fruit. The addition of the silicone-based L-77 surfactant to the Kocide suspension markedly increased the spread of the droplets on cuticles and increased the penetration of Cu through fruit and abaxial leaf cuticles, both with stomatal pores, but not through astomatous adaxial leaf cuticles, which had much lower permeability. Urea and petroleum spray oil adjuvants had no effect on surface area of droplets or the penetration of Cu through leaf and fruit cuticles. Spray tank mixes of Cu fungicides with organosilicone surfactants should be avoided because these surfactants can enhance the penetration of Cu into citrus leaves and fruit thereby leading to phytotoxicity.
Seasonal Variation in Growth, Nitrogen Uptake and Allocation by Container-grown Evergreen and Deciduous Rhododendron Cultivars
Authors: Scagel Carolyn F. , Bi Guihong , Fuchigami Leslie H. , Regan Richard P.
Published: February 2019

Growth, nitrogen (N) uptake, and N storage were assessed in transplanted 1-year-old rhododendron liners. Two evergreen cultivars, Rhododendron ‘P. J. Mezitt Compact’ (PJM) and R. ‘English Roseum’ (ER), and one deciduous cultivar, R. ‘Gibraltar’ (AZ), were transplanted into 1-gal. pots and given liquid fertilizer with (+N) or without (–N) N. Increased N availability increased growth after July (ER, PJM) or August (AZ), and resulted in three to five times more total biomass. Biomass continued to increase after stem elongation and leaf production ceased. Nitrogen uptake was correlated with growth of all plant structures on AZ, whereas N uptake was only correlated with stem and leaf growth on evergreen cultivars. The rate of N uptake was highest before July for AZ (1.9 mg·d−1) and in August and September for the evergreen cultivars (≈5 mg·d−1). Thirteen percent to 16% of total N uptake from between May and February occurred after N fertilization ceased at the beginning of September. Plants contained the most N in October (AZ), November (PJM), or December (ER). Biomass loss after November accounted for a loss of 14% to 48% of the maximum total plant N content. Nitrogen demand by roots and stems increased from May to February in all cultivars. The role of new and old leaves in N storage on evergreen cultivars varied with cultivar and time. Differences in N storage between the evergreen cultivars occurred primarily in their roots and leaves. Over the winter, PJM stored more N in its roots, whereas ER stored more N in its leaves. Changes in N concentrations and contents in different plant structures after November indicate that, during early winter, N stored in other structures moves to roots and old stems of PJM, old stems of ER, and roots and new and old stems of AZ. These results suggest that fertilizer application strategies for transplanted liners of these cultivars should include low N availability after transplanting followed by high N availability in mid to late summer. This type of strategy will not only improve N uptake efficiency from fertilizer, but also will minimize N loss from the containers. The results also demonstrated that N uptake in the autumn may play an important role in supplementing plant N reserves required for growth during the next season as well as for balancing N losses incited by leaf abscission, root turnover, and maintenance functions that occur over winter.
Inhibition of Astringency Removal in Semidried Japanese Persimmon Fruit by 1-methylcyclopropene Treatment
Authors: Matsumoto Toshikazu , Matsuzaki Hajime , Takata Kou , Tsurunaga Yoko , Takahashi Hiroyasu , Kurahashi Takao , Maki Shinya , Fujiwara Kazushi
Published: February 2019

The inhibition of astringency removal on semidried persimmon fruit treated with 1-methylcyclopropene (1-MCP) was investigated. The rate at which soluble tannin decreased in 1-MCP-treated semidried fruit was less than control fruit, the soluble tannin concentration in dried flesh of 1-MCP-treated fruit was more than 150 mg·100 g−1 on a fresh weight (FW) basis and, with sulfur treatment, reached 270 mg·100g−1 FW [which exceeds the concentration of tannins required to detect astringency (Inari and Takeuchi, 2001)], and the degree of inhibition for astringency removal in semidried fruit was different among cultivars. It is suggested that these phenomena occur by the inhibition of ethylene action for fruit softening by 1-MCP treatment.
SFBs of Japanese Plum (Prunus salicina): Cloning Seven Alleles and Determining Their Linkage to the S-RNase Gene
Authors: Sapir Gal , Stern Raphael A. , Goldway Martin , Shafir Sharoni
Published: February 2019

Japanese plum (Prunus salicina Lindl.), a species of the Rosaceae family, carries the S-RNase-mediated gametophytic self-incompatibility system. Self-incompatibility is manifested if the S-haplotype of the pollen is carried also by the pollinated flower. Thus, for fertilization to occur, the cultivars have to be genetically compatible. The haplotype is conferred by an S-locus, which contains the style-specific expressed S-RNase and the pollen-specific expressed F-box genes (SFB). Since both the S-RNase and the SFB genes are multiallelic and are characteristic of each of the S-haplotypes, they are ideal markers for molecular S-typing. In this work, seven SFBs, from eight japanese plum cultivars, were cloned and sequenced. Five of the alleles were published recently and two SFBg and SFBk
are new. The physical linkage of SFBb
and SFBc
to their adjacent S-RNase was determined; it is 544 base pairs (bp) and 404 bp for the Sb
and Sc
loci, respectively.
Field Evaluation of 64 Apple Rootstocks for Orchard Performance and Fire Blight Resistance
Authors: Russo Nicole L. , Robinson Terence L. , Fazio Gennaro , Aldwinckle Herb S.
Published: February 2019

In 2002, apple rootstock trials using three scion cultivars were established at Geneva, NY, to evaluate 64 apple (Malus ×domestica Borkh.) rootstocks for horticultural performance and fire blight resistance. Field trials compared several elite Geneva® apple rootstocks, which were bred for tolerance to fire blight and Phytophthora root rot, to both commercial standards and elite rootstock clones from around the world. Three rootstocks performed well with all scion cultivars: ‘B.9’, ‘Geneva® 935’, and ‘Geneva® 41’. All three rootstocks were similar in size to ‘M.9’ clones but with elevated yield efficiency and superior resistance to fire blight. ‘Geneva® 11’ also performed very well with ‘Golden Delicious’ and ‘Honeycrisp’ with regard to yield efficiency and disease resistance. Resistant rootstocks greatly enhanced the survival of young trees, particularly with the susceptible scion cultivars ‘Gala’ and ‘Honeycrisp’. Results demonstrate the ability of new rootstock clones to perform better than current commercial standards, reducing financial risk to producers while promoting orchard health with enhanced disease resistance.
Pseudo-xenic Effect of Allied Annona spp. Pollen in Hand Pollination of cv. ‘Arka Sahan’ [(A. cherimola × A. squamosa) × A. squamosa]
Authors: Jalikop S.H. , Kumar Ravindra
Published: February 2019

Annonaceous fruits are characterized by a serious problem of fruit set, and hand pollination is commonly practiced for improving the set. Because we observed that allied Annona spp. are freely crossable and often produce attractive Fo fruits, the possibility of using their pollen in hand pollination was investigated. A total of 1080 flowers of cv. Arka Sahan in 2003 and 3420 in 2004 were pollinated with A. atemoya Hort., A. cherimola Mill., A. reticulata L., A. squamosa L., and self-pollen. Pollen source had significant effects in both or either year on all 14 fruit traits studied except days to ripening. A. squamosa pollen gave the highest fruit set (greater than 91%) and the heaviest fruits (greater than 600 g). Good to moderate fruit set was recorded with A. reticulata and self-pollen (31% to 86%); and with A. atemoya and A. cherimola pollen, the set was poor (4% to 13%), whereas natural set was as low as 2%. ‘Arka Sahan’ fruits resulting from A. squamosa pollen showed quicker fruit maturity (128 days) and least weight loss on ripening (13%). Evaluation of fruit pulp quality revealed that pollen source and year had significant effects on the total soluble solids and acidity but not their ratio. Mean number of seeds per 100 g fruit was found to vary (6 to 11) with pollen source used. A. squamosa and A. reticulata pollen had higher seed count with good to moderate fruit size and symmetrical shape, but those from the rest of the pollen sources neither possessed good size nor shape. Results clearly showed that ‘Arka Sahan’ could be successfully hand pollinated with A. squamosa pollen. The differential ability of pollen sources to fertilize number of ovules and set seeds per fruit rather than the pollen genotype had a significant effect on many fruit traits like size, symmetry, skin thickness, and total soluble solids, which we describe as ”pseudo-xenia.” Useful pseudo-xenic effect is worth exploiting in fruit culture.
Identification and Classification of Main Iranian Olive Cultivars Using Microsatellite Markers
Authors: Noormohammadi Zahra , Hosseini-Mazinani Mehdi , Trujillo Isabel , Rallo Luis , Belaj Angjelina , Sadeghizadeh Majid
Published: February 2019

Numerous olive cultivars are cultivated in Iran, mainly in the north. Ninety-two accessions belonging to 10 main olive cultivars were screened by 13 microsatellite markers revealing high genetic variability both within and between cultivars. In total, 72 alleles were detected with a mean number of 5.5 alleles per locus. Twenty-four unique allelic patterns were observed, whereas six genotypes showed 15 unique alleles. Heterozygosity ranged from 0.00 to 0.98, whereas the mean number of discrimination power and polymorphic information content were 0.55 and 0.54, respectively. The combination of 5 simple sequence repeat markers made discrimination of 84% of all accessions included in the study possible. The existence of homonyms, synonyms, or mislabeling as well as intracultivar polymorphism was revealed by allele differences between accessions of the same denomination. The phenogram showed variability among as well as between some cultivars, but most accessions with the same generic names were grouped together.
Laboratory Method to Estimate Rain-induced Splitting in Cultivated Blueberries
Authors: Marshall Donna A. , Spiers James M. , Stringer Stephen J. , Curry Kenneth J.
Published: February 2019

Preharvest rainfall that occurs when fruit are fully ripe or approaching full ripeness can result in detrimental fruit splitting in rabbiteye and southern highbush blueberries. This study was initiated to develop a laboratory method to model rain-related incidence of splitting in cultivated blueberries with the goal of predicting the incidence of splitting in blueberry cultivars and selections. Multiyear field surveys of rabbiteye and southern highbush cultivars show that the incidence of rain-related splitting is strongly cultivar-dependent. Laboratory values for forced splitting and naturally occurring rain-related field splitting data show a strong correlation indicating that the incidence of fruit splitting can be accurately estimated by this laboratory method. Soaking the berries in distilled water 14 h at room temperature gives a confident determination of splitting tendencies. Blueberry breeders and geneticists can use this method to evaluate new potential blueberry cultivars for splitting tendencies as part of routine screening. This would lead to a long-term goal of reducing splitting susceptible blueberry cultivars in commercial plantings.
Node Type Development of Four Low-chill Peach Cultivars at Three Locations in Florida
Authors: Wert Todd W. , Williamson Jeffrey G. , Chaparro Jose X. , Miller E. Paul , Rouse Robert E.
Published: February 2019

The effect of climate was observed on the relative frequency of vegetative and floral buds in four low-chill peach cultivars (‘Flordaprince’, ‘Flordaglo’, ‘UFGold’, and ‘TropicBeauty’). The trees were planted in north–central, central, and southwest Florida. The percentage of blind nodes, mixed nodes (nodes with vegetative and floral buds), and nodes with only vegetative buds were determined from three representative shoots per tree at each location. In general, higher percentages of blind nodes were observed in central and southwest Florida and higher percentages of mixed nodes were observed in north–central Florida. ‘TropicBeauty’ tended to have a greater percentage of blind nodes than the other cultivars. Higher temperatures during bud formation most likely contributed to the increased amounts of blind nodes observed in the central and southwest locations and to the reduced amounts of mixed nodes. However, stresses imposed by bacterial spot and hurricanes may have contributed to the higher incidence of blind nodes in 2005. Our results indicate that certain genotypes have a predisposition for the formation of blind nodes. Advanced selections having low chilling requirements and potentially being adapted to a wide diversity of tropical or subtropical climates need to be tested in multiple locations to evaluate blind node formation.
Effects of CPPU Applications on Southern Highbush Blueberries
Authors: Williamson Jeffrey G. , NeSmith D. Scott
Published: February 2019

Greenhouse and field experiments were conducted to determine the effects of the growth regulator N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) on fruit set, berry size, and yield of southern highbush blueberry (Vaccinium corymbosum hybrids). The experiments were conducted over a period of several years in Georgia and Florida. CPPU sprays were capable of increasing fruit set and berry weight of southern highbush blueberry, although the responses to CPPU treatment were variable and appeared to be influenced by factors such as rate, spray timing, and cultivar. In Florida, high natural fruit set may have prevented increased fruit set from CPPU. A slight delay in berry maturity was noted in several experiments. Spray burn occurred on several occasions and may be related to factors such as cultivar, rate, spray volume, and use of surfactant.
Seasonal Abundance and Insecticidal Control of Citrus Leafminer in a Citrus Orchard
Authors: Powell Charles A. , Burton Michael S. , Pelosi Robert , Ritenour Mark A. , Bullock Robert C.
Published: February 2019

Population density of citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), was monitored in a Florida citrus grove for 5 years by scouting weekly for larval-induced mines (leafminer-created tunnels in the leaves) in a replicated citrus plot treated with seven insect control regimes: Admire (imidacloprid) applied at 12, 6, 3, or 2-month intervals; Temik (aldicarb) applied annually; Metasystox-R (oxydemeton-methyl) applied annually; or no insect control. Leafminer populations were highest during the warmer months (April to September) and lowest during the cooler months (November to March). Populations peaked during June in all 5 years monitored. Trees treated with Temik or Metasystox-R had the same number of mines as the untreated controls. A biannual treatment with Admire reduced leafminer damage (number of mines) all 5 years compared with the controls. Additional Admire applications further reduced damage during some, but not all, years. A single application of Admire significantly reduced mines in 3 of the 5 years.
Evaluation of Daphne Germplasm for Resistance to Daphne Sudden Death Syndrome Caused by the Soil-borne Pathogen Thielaviopsis basicola
Authors: Noshad David , Riseman Andrew , Punja Zamir
Published: February 2019

Many daphne cultivars are susceptible to fungal root pathogens and require frequent fungicide applications during production. To identify taxon differences to disease susceptibility, we evaluated 32 Daphne species and cultivars for resistance to the soil-borne pathogen, Thielaviopsis basicola (Berk. and Broome) Ferr., by both in vitro- and in vivo-based methods. Disease-free plant roots were inoculated with the pathogen through topical application of a spore suspension and observed weekly for disease development/progression. Significant variation for disease severity among the taxa evaluated was determined using a plant disease index. Plant reactions ranged from highly resistant, e.g., D. tangutica and D. retusa, to highly susceptible, e.g., D. cneorum. In addition, a high correlation was found between the in vitro and in vivo techniques for the seven selected species, indicating that they are comparable. However, the in vitro assay provided results in significantly less time than the in vivo assay.
Responses of ‘Golden Delicious’ Apples to 1-MCP Applied in Air or Water
Authors: Argenta Luiz C. , Fan Xuetong , Mattheis James P.
Published: February 2019

The efficacy of the ethylene action inhibitor 1-methylcyclopropene (1-MCP) applied in water to slow ripening of ‘Golden Delicious’ [Malus sylvestris var. domestica (Borkh.) Mansf.] apples was evaluated in comparison with 1-MCP applied in air. The material was applied by dipping fruit in 1-MCP water solutions (0.03, 0.3, or 3 mmol·m−3) for 4 min or by exposing fruit to 1-MCP gas (0.42, 4.2, or 42 μmol·m−3) in air for 12 h. Fruit were held in air at 20 °C for 25 days after treatment or stored at 0.5 °C in air for up to 6 months followed by 7 days in air at 20 °C. Application of 1-MCP in water or air delayed the increase in respiration and ethylene production associated with fruit ripening and reduced the amount of fruit softening, loss of acidity, and change in peel color. Treatments applied in water required a 700-fold higher amount of active ingredient compared with treatments applied in air to induce similar physiological responses. Fruit responses to 1-MCP varied with treatment concentration, and the maximum effects were obtained at concentrations of 4.2 or 42 μmol·m−3 in air and 3 mmol·m−3 in water. Peel color change was impacted less than retention of firmness and titratable acidity for 1-MCP treatments applied at concentrations of 4.2 or 42 μmol·m−3 in air and 0.3 or 3 mmol·m−3 in water. Treatment with 1-MCP in air or water was less effective for slowing peel degreening when treated fruit were stored at 0.5 °C compared with storage at 20 °C. Fruit treated with 1-MCP and stored in air at 0.5 °C developed a peel disorder typified by a gray·brown discoloration that is unlike other disorders previously reported for this cultivar. Symptoms were present when fruit were removed from cold storage and no change in symptom appearance was observed during a 7-d holding period at 20 °C.
Yield and Nutritional Quality of Canola Sprouts
Authors: Bhardwaj Harbans L. , Hamama Anwar A.
Published: February 2019

In recent times, the use of sprouted seeds has become popular in human diets. Considerable information is available in the literature about various types of sprouts such as alfalfa, mungbean, and radish. However, information about canola (Brassica napus L.) sprouts, an oilseed crop that is receiving serious consideration as a source of domestic oil for human consumption, is lacking. We studied the composition traits of sprouts made from four canola cultivars (‘Banjo’, ‘KS8200’, ‘KS8227’, and ‘Virginia’) grown at three locations (Orange, Petersburg, and Suffolk) in Virginia for two crop seasons (2001 to 2002 and 2002 to 2003). Two 20-g seed samples (two replications) of each cultivar × location combination were sprouted for 6 d in the laboratory using tap water. Sprouting of canola seeds increased the weight 5.6 times over the original seed weight. Canola sprouts, on average, contained 27.3% oil, 25.1% protein, and 10.8% crude fiber on dry weight basis. Fresh yield of canola sprouts, from 20-g seed, averaged 111.1 g, whereas moisture content averaged 80.3%. Effects of cultivars on fresh sprout yield and moisture content were not significant. Locations where seeds were grown had significant effects on all traits of canola sprouts except for fresh sprout yield. Canola sprouts made from seed of ‘Virginia’ cultivar had the highest protein content (26.2%), whereas those made from seeds of ‘KS8227’ cultivar had the highest oil content (28.7%). Based on traits under study, canola sprouts compared well with alfalfa, brussel sprouts, mungbean, and radish sprouts for overall nutritional quality.
In vitro Propagation of Lychnophora pinaster (Asteraceae): A Threatened Endemic Medicinal Plant
Authors: de Souza Ana V. , Pinto José E.B.P. , Bertolucci Suzan K.V. , Corrêa Ricardo M. , Costa Larissa C. do B. , Dyer William E.
Published: February 2019

Lychnophora pinaster, known as arnica, is a medicinal plant of the Cerrado ecosystem in Brazil. It is widely used in the form of alcoholic extract for its anti-inflammatory and anesthetic and healing effects on sprains, bruises, and inflammation. Owing to the great difficulty of propagation, it is listed by the Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis in the category of plants vulnerable to extinction. Micropropagation offers a solution to this problem by allowing the preservation and expansion of germplasm. The objective of this research was to establish a protocol for in vitro propagation of arnica. The best medium for germination of arnica embryos and plantlet growth was a quarter strength semisolid Murashige and Skoog medium (MS/4) containing 0.75% (w/v) sucrose. For shoot induction, the best results were obtained on MS/4 with 2.76 μm of benzylaminopurine. Maximum shoot elongation before rooting occurred in the presence of 8.67 μm of gibberellic acid for 19 d. Microshoots were successfully rooted in the presence of 10.7 μm of naphthalene acetic acid for 15 d. After rooted plantlets were acclimatized in a greenhouse for 20 d, the survival rate was 100% when planted in a soil from the area of occurrence of the species, whereas 0% survived when planted in Plantmax.
Overcoming Compaction Limitations on Cabbage Growth and Yield in the Transition to Reduced Tillage
Authors: Mochizuki Maren J. , Rangarajan Anusuya , Bellinder Robin R. , Björkman Thomas , van Es Harold M.
Published: February 2019

Vegetable producers are increasingly interested in adopting conservation tillage practices to maintain or enhance productivity and soil health, but reducing tillage may reduce yields in cool climates. Strategies to transition from full-width tillage to zone tillage systems for cabbage (Brassica oleracea L. Group capitata) were tested with the goals of overcoming soil temperature and compaction limitations and producing crop yield and quality equivalent to conventionally tilled. Designed to achieve differential soil temperature and compaction levels, the treatments were factorial combinations of two widths of zone tillage (15 and 30 cm) and two depths of zone tillage (10 and 30 cm) plus a conventional rototilled treatment (full width and 20-cm depth) as a control. To assess the effect of treatments in the transitional year to reduced tillage, the experiment was conducted in 2003 and 2004 at different fields that were previously conventionally tilled. Increasing tillage width from 15 cm to 30 cm increased soil temperature by 1 °C in both years but had a limited effect on cabbage growth and no effect on yield. Tillage width and soil temperature may have greater impact on an earlier planting. By contrast, increasing tillage depth from 10 cm to 30 cm reduced soil penetrometer resistance by up to 1 MPa, increased plant growth by 28%, and increased yield by 22%. Growth and yield in 30-cm depth treatments were similar to conventional tillage, indicating the undisturbed, between-row areas in zone tillage treatments did not restrict growth. Zone tillage did not affect cabbage maturity or quality. Tillage depth was more important to the success of this system than tillage width; vertical tillage to 30-cm depth left between 60% and 80% of the soil surface area undisturbed and can be an effective transition to conservation tillage for transplanted cabbage.
Drought Tolerance Responses of Purple Lovegrass and ‘Adagio’ Maiden Grass
Authors: Alvarez Erin , Scheiber S.M. , Beeson Richard C. , Sandrock David R.
Published: February 2019

Nonnative Miscanthus sinensis Anderss ‘Adagio’ and native Eragrostis spectabilis (Pursh) Steud. were evaluated for drought tolerance in a rain-excluded landscape setting in sandy soil in response to irrigation application volumes of 0 L, 0.25 L, 0.5 L, or 0.75 L. As irrigation rates increased, plant mass, canopy size, and shoot-to-root ratios increased for both species, being greatest at the 0.75-L rate. Shoot dry weight, root dry weight, total biomass, and shoot-to-root ratios were greater for E. spectabilis than M. sinensis. Cumulative water stress integral was also greater for E. spectabilis. Greater growth in conjunction with higher cumulative water stress indicates the native E. spectabilis is anisohydric and more drought-tolerant than the isohydric nonnative M. sinensis.
Early Differences in the Intensity of Alternate Bearing Among Selected Pistachio Genotypes
Authors: Kallsen Craig E. , Parfitt Dan E. , Holtz Brent
Published: February 2019

Alternate bearing (alternating years with high and low yields) is a prominent characteristic of ‘Kerman’ pistachio (Pistacia vera L.), the primary California cultivar. The degree of alternate bearing is described by alternate bearing index values from 0 (identical yields every year) to 1 (complete alternate bearing). Two separate and replicated trials designed to evaluate selections from a breeding program were conducted in the southwest (Kern County) and northeast (Madera County) areas of the San Joaquin Valley of California. Yields from the scion genotypes ‘Kerman’, ‘Golden Hills’, ‘Lost Hills’, ‘B5-8’, and ‘B19-1’ on PG1 rootstock were measured from 5- to 9-year-old trees in Kern County and from 5- to 7-year-old ‘Kerman’, ‘Golden Hills’, ‘Lost Hills’, and ‘B5-8’ trees on PG1 and UCB1 rootstock in Madera County. In Kern County, average annual yields among genotypes varied from a low of 208 to a high of 5273 kg·ha−1. Differences in the alternate bearing indices among genotypes were significant and ranged from 0.10 for ‘Lost Hills’ to 0.80 for ‘B19-1’. A similar pattern was observed for alternate bearing indices at the Madera County trial. In this younger trial, scion genotype had more influence on alternate bearing indices than did rootstock. Marked differences in the intensity of alternate bearing of young trees in these two trials suggest that alternate bearing might be amenable to selection in breeding programs. However, the observation that ‘B5-8’, with an alternate bearing index of 0.74, varied significantly from its female parent ‘Kerman’ at 0.36 suggests that inheritance is complex.
Black Currant Clonal Identity and White Pine Blister Rust Resistance
Authors: Burnes Todd A. , Blanchette Robert A. , Smith Jason A. , Luby James J.
Published: February 2019

Gooseberries and currants (Ribes L.) are the alternate hosts for the fungus Cronartium ribicola J. C. Fischer, the causal agent of white pine blister rust. In this study, 16 black currant (R. nigrum L.) cultivars, including three accessions of the putatively immune cultivar ‘Consort’ and three cultivars developed at the University of Minnesota Horticultural Research Center, were screened for resistance to C. ribicola using artificial inoculation procedures. Twelve of these cultivars were grown in the field and observed for natural infection. Cultivars ‘Ben Sarek’, ‘Ben Lomond’, and ‘C2-2-1’ were infected naturally in the field at the University of Minnesota Horticultural Research Center in 2000, 2001, and 2004. Cultivars ‘Ben Sarek’, one mislabeled ‘Consort’ accession, R. nigrum ‘WI-1’, and ‘Ben Lomond’ had significantly more uredinial sori than other cultivars when inoculated artificially. To determine if the infected and noninfected ‘Consort’ clones were genetically related, DNA microsatellite genotyping was carried out to fingerprint these clones. One of the six microsatellite loci resulted in a polymorphism that indicated the infected clone was genetically different from the noninfected clones. In addition, the inoculation procedures used in these studies are generally efficacious for predicting resistance in the field because none of the field-infected cultivars were resistant in the greenhouse. This study confirms the Cr gene for resistance to C. ribicola in Ribes has remained effective for over 50 years.
Mulching Options for Northwest Organic and Conventional Orchards
Authors: Granatstein David , Mullinix Kent
Published: February 2019

The semiarid climate of the Pacific Northwest allows for the production of organic, temperate tree fruit relatively free of disease and with fewer key insect pests compared with other regions of the United States. Weed control and soil fertility are two of the higher cost areas for organic tree fruit where alternatives are being sought through research and on-farm innovation. Mulches, both living [e.g., white clover [(Trifolium repens)] and inert (e.g., wood chips) show promise for controlling weeds, conserving water, providing nitrogen (N), or improving tree growth, but potentially have system trade-offs such as increased rodent pests and unwanted late-season N. Growers need orchard floor management practices that help them maintain or improve soil quality per the requirements of the National Organic Standards.
Turgor Closely Relates to Postharvest Fruit Softening and Can Be a Useful Index to Select a Parent for Producing Cultivars with Good Storage Potential in Apple
Authors: Iwanami Hiroshi , Moriya Shigeki , Kotoda Nobuhiro , Abe Kazuyuki
Published: February 2019

Changes in turgor and flesh firmness during storage at 20 °C were investigated using 27 apple (Malus ×domestica Borkh.) cultivars for 2 years. Flesh firmness was measured using a penetrometer, and turgor was determined using a thermocouple psychrometer. Firmness and turgor of fruit decreased during storage. The cultivars with little softening during storage had low rates of reduction in turgor. The softening rates in mealy cultivars were high, but there were cultivars with low rates of turgor reduction. When the rates of reduction in turgor after harvest were low, the mealy cultivars of the fruit tended to develop severe mealiness during storage. Therefore, a low rate of reduction in turgor could contribute to cultivars with both good shelf life and severe mealiness. The reduction rates of turgor in progeny cultivars were nearly identical to the mean reduction rates of turgor of their parents. This suggests that a cultivar with a low reduction rate of turgor, although it can be mealy, has the potential to produce a progeny with a low reduction rate of turgor.
Planting Method, Plastic Mulch, and Fumigation Influence Growth, Yield, and Root Structure of Watermelon
Authors: Egel Daniel S. , Martyn Ray , Gunter Chris
Published: February 2019

A 2-year field study was conducted to determine the influence of planting method, i.e., transplanting or direct seeding, black plastic mulch, and soil fumigation on the vine growth, yield, and root structure of diploid hybrid watermelon. The experiment was a split-plot design with fumigation as the main plot and there were four replications. Methyl bromide (337 L·ha−1) was applied to the soil, which was then tarped. Black plastic mulch, 0.61 m wide × 2 mil (Visqueen 4020™) was applied to appropriate rows. Vine growth was measured during the season and yield was determined by the number and weight of fruit from each treatment. After fruit harvest, plant roots were excavated so that root structure was maintained with minimal damage and roots were photographed. Root systems were scored for tap root dominance and overall root distribution. Direct-seeded watermelon had more vine growth and higher yields in both years than transplanted watermelon. The advantage of direct seeding was likely the result of the growth and root expansion that occurred for these plants while the transplants were still in the greenhouse. Direct-seeded plants also displayed greater tap root dominance in each year than transplanted watermelon. Roots of both direct-seeded plants and transplants had a greater range in size distribution in both years under plastic mulch than those grown on bare ground. In late-planted watermelon, direct-seeded plants had more favorable vine growth and yield without the aberrant roots systems produced by transplants.
Foliar Boron and Nickel Applications Reduce Water-stage Fruit-split of Pecan
Authors: Wells M. Lenny , Wood Bruce W.
Published: February 2019

Water-stage fruit-split (WSFS) is a relatively common and often major problem of certain pecan [Carya illinoinensis (Wangenh.) K. Koch] cultivars. This study evaluates the possibility that the malady can be influenced by improving tree micronutrient nutrition. Foliar sprays of boron (B) and nickel (Ni) to WSFS-susceptible fruit of ‘Cape Fear’ and ‘Sumner’ are evaluated based on the possibility that either B or Ni potentially affects the severity of WSFS exhibited by trees. Although the incidence of WSFS on ‘Cape Fear’ was unaffected by micronutrient sprays, the severity of WSFS was substantially reduced in each of the 3 study years by foliar B application and in 2005 by foliar Ni application. Repeated foliar sprays of Ni also reduced WSFS of ‘Sumner’ fruit. These data indicate that improving either B or Ni nutrition can potentially reduce crop loss resulting from WSFS in certain orchard situations and provides evidence that insufficient availability of B or Ni to developing ovary tissues potentially predisposes developing fruit to WSFS when environmental triggers occur.
Effect of Sprayable 1-MCP, AVG, and NAA on Ethylene Biosynthesis, Preharvest Fruit Drop, Fruit Maturity, and Quality of ‘Delicious’ Apples
Authors: Yuan Rongcai , Li Jianguo
Published: February 2019

Effects of naphthaleneacetic acid (NAA), aminoethoxyvinylglycine (AVG), and sprayable 1-methylcyclopropene (1-MCP) alone or in combination on fruit ethylene production, preharvest fruit drop, fruit quality, and fruit maturation were examined in ‘Delicious’ apples (Malus ×domestica Borkh.). 1-MCP and AVG + NAA, when applied 15 days before anticipated harvest (DBAH) for untreated control trees, more effectively delayed preharvest fruit drop than AVG or NAA used alone. However, there was no significant difference in ethylene production between fruit treated with 1-MCP or AVG + NAA and those treated by AVG. Two applications of NAA increased fruit ethylene production and fruit softening, whereas AVG inhibited NAA-enhanced fruit ethylene production and fruit softening. There was no significant difference in fruit ethylene production, fruit firmness, and fruit drop control between one and two applications of 1-MCP. The concentrations of 1-MCP did not affect the efficacy of 1-MCP when applied 15 DBAH, but high concentration of 1-MCP more effectively delayed preharvest fruit drop than low concentration of 1-MCP when applied 7 DBAH. Both AVG and 1-MCP suppressed expression of 1-aminocyclopropane-1-carboxylate (ACC) synthase gene MdACS1, ACC oxidase gene MdACO1, and polygalacturonase gene MdPG1 in fruit. Expression of ACS5A and MdACO1 but not MdACS1 in fruit abscission zones was decreased by AVG and 1-MCP. 1-MCP more effectively suppressed expression of MdPG2 in fruit abscission zones than AVG alone.
Weed Management in Transplanted Bell Pepper (Capsicum annuum) with Pretransplant Tank Mixes of Sulfentrazone, S-metolachlor, and Dimethenamid-p
Authors: Robinson Darren E. , McNaughton Kristen , Soltani Nader
Published: February 2019

Pepper growers currently have limited access to many effective broadleaf herbicides. Field trials were conducted over a 3-year period in Ontario to study the effect of tank mixtures of sulfentrazone (100 or 200 g·ha−1 a.i.) with either s-metolachlor (1200 or 2400 g·ha−1 a.i.) or dimethenamid-p (750 or 1500 g·ha−1 a.i.) on transplanted bell pepper. Under weed-free conditions, there was no visual injury or reduction in plant height, fruit number, fruit size, or marketable yield of transplanted pepper with pretransplant applications of sulfentrazone applied in tank mixtures with s-metolachlor or dimethenamid-p. The tank mixture of sulfentrazone + s-metolachlor gave greater than 85% control of redroot pigweed (Amaranthus retroflexus) and eastern black nightshade (Solanum ptycanthum), but only 70% to 76% control of velvetleaf (Abutilon theophrasti), common ragweed (Ambrosia artemisiifolia), and common lambsquarters (Chenopodium album). The combination of sulfentrazone + dimethenamid-p provided good to excellent control of all weed species except velvetleaf. Based on this study, sulfentrazone and dimethenamid-p have potential for minor use registration in pepper.
Generation and Characterization of Transgenic Plum Lines Expressing the Gastrodia Antifungal Protein
Authors: Nagel Alexis K. , Schnabel Guido , Petri Cesar , Scorza Ralph
Published: February 2019

The Gastrodia antifungal protein (GAFP) is a monocot mannose-binding lectin isolated from the Asiatic orchid Gastrodia elata. This lectin has previously been shown to provide increased resistance in transgenic Nicotiana tabacum against taxonomically unrelated root pathogens Phytophthora nicotianae, Rhizoctonia solani, and Meloidogyne incognita, but its potential to confer disease resistance in tree species is not known. Agrobacterium tumefaciens-mediated transformation yielded three gafp-1 expressing plum lines (Prunus domestica) designated 4J, 4I, and 5D. These lines possessed one, two, and four copies of the gafp-1 gene, respectively, as demonstrated by DNA blotting. Lines 4J and 4I were not phenotypically different from the nontransformed control line, but line 5D showed significant divergence in leaf morphology and growth habit. Compared with the inoculated control line, lines 4J and 4I exhibited increased tolerance to Phytophthora root rot (PRR) caused by P. cinnamomi. When inoculated with the root-knot nematode, Meloidogyne incognita, the 4J and 4I lines showed a significantly lower degree of root galling than the inoculated control line. Nematode reproduction, as measured by the presence of egg masses and the number of eggs produced per gram fresh root, was significantly reduced in line 4J compared with the inoculated control line. The results of this study suggest that the expression of gafp-1 in the roots of a woody plant may confer some level of resistance to PRR and root-knot nematode. Long-term field trials will be necessary to confirm this hypothesis.
Morphology and Irrigation Efficiency of Gaura lindheimeri Grown with Capacitance Sensor-controlled Irrigation
Authors: Burnett Stephanie E. , van Iersel Marc W.
Published: February 2019

Gaura lindheimeri Engelm. & Gray ‘Siskiyou Pink’ (gaura) and Phlox paniculata L. ‘David’ (garden phlox) were grown for 5 weeks in substrates irrigated at volumetric water contents (Θ) of 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, or 0.45 m3·m−3 using a capacitance sensor-controlled irrigation system. Volumetric water contents of the substrate measured by the capacitance sensors controlling irrigation were correlated with measurements with a separate handheld meter (r
2 = 0.83) and with volumetric water content set points throughout the study (r
2 > 0.98). Only 3.8 (at an irrigation set point of 0.10 m3·m−3) to 53 L (0.45 m3·m−3) of water was used to irrigate gaura and phlox and 0 to 7.74 L of this water leached out of the substrates. Significant leaching occurred only at Θ set points of 0.40, or 0.45 m3·m−3. Gaura had shorter and fewer branches and reduced dry weight when grown at lower volumetric water contents, but plants irrigated at set points above 0.25 m3·m−3 were large enough to be marketable. Gaura may be grown with capacitance sensor-automated irrigation using water efficiently and minimizing or eliminating leachate and thus nonpoint source pollution.
Effect of Fertilizer Rate on Growth of Azalea and Holly in Pine Bark and Pine Tree Substrates
Authors: Jackson Brian E. , Wright Robert D. , Browder Jake F. , Roger Harris J. , Niemiera Alex X.
Published: February 2019

Recent interest in the use of wood substrates in horticulture crop production has justified the need for determining fertilizer requirements in these substrates compared with traditional pine bark (PB) and peatmoss substrates. The objective was to determine the response of japanese holly (Ilex crenata Thunb. ‘Compacta’) and azalea (Rhododendron obtusum Planck. ‘Delaware Valley’) grown in a pine tree substrate (PTS) (trade name WoodGro™) or milled PB to fertilizer rate. Pine tree substrate is produced from freshly harvested loblolly pine trees (Pinus taeda L.) that are delimbed, chipped, and ground in a hammer mill to a desired particle size. Japanese holly plants were grown in 2.8-L containers in the fall of 2005 and again in the spring of 2007 with the addition of azalea. Plants grown in PTS or PB were fertilized by incorporating Osmocote Plus fertilizer (15N–3.9P–10K) at rates of 3.5, 5.9, 8.3 or 10.6 kg·m−3 for japanese holly and 1.2, 3.5, 5.9, or 8.3 kg·m−3 for azalea. After 3 months, shoot dry weights were determined for japanese holly and azalea. Japanese holly root dry weights were determined for both experiments, and substrate CO2 efflux (μmol CO2 m−2·s−1) was measured on the treatments at the end of the experiment using a LI-6400 soil CO2 flux chamber. In 2005, japanese holly shoot dry weights of PTS-grown plants were comparable to plants grown in PB at the 8.3 kg·m−3 fertility rate, and shoot dry weights of PTS-grown plants were higher than PB at the 10.6 kg·m−3 rate. In 2007, japanese holly and azalea shoot dry weights of PTS-grown plants were comparable to PB plants at the 5.9 kg·m−3 fertilizer rate. Both japanese holly and azalea achieved shoot growth in PTS comparable to shoot growth in PB with ≈2.4 kg·m−3 additional fertilizer for PTS. Substrate CO2 efflux rates were higher in PTS compared with PB indicating higher microbial activity, thereby increasing the potential for nutrient immobilization in PTS.
Potato Maximum Yield as Affected by Crop Parameters and Climatic Factors in Brazil
Authors: Pereira André , Nova Nilson Villa
Published: February 2019

There is currently a great deal of interest in estimating crop productivity as a function of climatic factors by means of different crop weather models. In this article, an agrometeorological model based on maximum carbon dioxide assimilation rates for C3 plants, fraction of photosynthetically active radiation, air temperature, photoperiod duration, and crop parameters is assessed as to its performance under tropical conditions. Crop parameters include leaf area, harvest index, dry matter content of potato tubers, and crop cycles to estimate potential potato yields. Productivity obtained with the cultivar Itararé, grown with adequate soil water supply conditions at four different sites in the state of São Paulo (Itararé, Piracicaba, Tatuí, and São Manuel), Brazil, was used to test the model. The results revealed excellent performance of the agrometeorological model proposed here with an underestimation of irrigated potato productivity of less than 10%.