bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Cowpea Genotypes for Use as a Cover Crop
Authors: Harrison Howard F. , Thies Judy A. , Fery Richard L. , Smith J. Powell
Published: February 2019

A preliminary screening experiment was conducted to evaluate 47 cowpea [Vigna unguiculata (L.) Walp.] genotypes for use as a weed-suppressing cover crop. Of these, 11 were selected for further testing on the basis of vigorous growth and weed-suppressing ability. In a field experiment repeated over 4 years, the selected genotypes were not different from the leading cover crop cultivar `Iron Clay' in biomass production. Vigor ratings, vine growth ratings, and canopy widths of some genotypes exceeded those of `Iron Clay' Vigor ratings and canopy measurements were efficient selection criteria that could be useful for breeding cover crop cowpea cultivars. All except one selection were highly resistant to southern root knot nematode [Meloidogyne incognita (Kofoid and White) Chitwood], and the selections varied in seed size, photoperiod, and response to foliar diseases.
Molecular Confirmation of Intergeneric Hybrid ×Chitalpa tashkentensis (Bignoniaceae)
Authors: Li Jianhua , Shoup Suzanne , Li Jianhua , Elias Thomas S.
Published: February 2019

Intergeneric hybrids are generally rare; nevertheless, such putative hybrids need confirmation from other lines of evidence besides morphological intermediacy. In this study the authors used DNA sequences of nuclear and chloroplast genes to determine the hybrid identity of ×Chitalpa. Their results confirm that both ×Chitalpa tashkentensis `Pink Dawn' and ×C. tashkentensis `Morning Cloud' are the result of an Chilopsis linearis ×Catalpa sp. cross. However, Catalpa bignonioides does not seem to have participated in the cross, as speculated before. Different species of Catalpa may have been used as the paternal parent. ×C. tashkentensis `Morning Cloud' is the result of the C. linearis × C. speciosa cross, whereas the paternal parent of ×C. tashkentensis `Pink Dawn' may be a hybrid plant of C. ovata and C. speciosa.
Soilless Media and Containers for Greenhouse Production of `Galia' Type Muskmelon
Authors: Rodriguez J.C. , Cantliffe D.J. , Shaw N.L. , Karchi Z.
Published: February 2019

In the spring of 2001 and 2002, different combinations of media (coarse perlite, medium perlite, and pine bark) and containers (polyethylene bags and plastic pots) were used for hydroponic production of `Galia' muskmelons (Cucumis melo L.) to determine their effect on fruit yield and quality, and their influence on costs of production. Marketable yields obtained for `Gal-152' in the spring 2001 and 2002 were 25.5 kg·m–2 and 39.0 kg·m–2 respectively. When data were combined for 2001 and 2002, fruit yield and fruit quality were unaffected by any combination of media and container. Average soluble solids content was generally greater than 10° Brix. It was determined that the use of pine bark media and plastic pots instead of perlite and bags would save $18,200 per year (two crops)—a feasible option for reducing costs of producing `Galia' muskmelons in greenhouses using soilless culture without loss of yield and fruit quality.
Tergitol-TMN-6 Surfactant Is an Effective Blossom Thinner for Stone Fruits
Authors: Fallahi Esmaeil , Fallahi Bahar , McFerson James R. , Byers Ross E. , Ebel Robert C. , Boozer Robert T. , Pitts Jim , Wilkins Bryan S.
Published: February 2019

Effects of Tergitol-TMN-6 surfactant on blossom thinning (fruit set), fruit quality, and yield were studied in different cultivars of peach (Prunus persica [L.] Batsch) during 2003 to 2005, and in one cultivar of nectarine Prunus persica [L.] in one orchard and one cultivar of plum (Prunus domestica [L.]) in two orchards in 2004. In addition to Tergitol-TMN-6, effects of Crocker's fish oil (CFO) alone in three peach cultivars or in combination with lime sulfur in a nectarine cultivar were studied on fruit set, quality, and yield. Tergitol-TMN-6 at 5 mL·L–1 or higher rates, applied at about 75% to 85% bloom, reduced fruit set without russeting peach fruit. Peach fruit size was often increased by Tergitol-TMN-6 treatment. Applications of Tergitol at 20 mL·L–1 or 30 mL·L–1 excessively thinned peaches. Tergitol-TMN-6 at all rates burned foliage, but the symptoms disappeared after a few weeks without any adverse effects on tree productivity. Tergitol-TMN-6 at 7.5 mL·L–1 or 10 mL·L–1, applied either once at about 80% to 85% bloom or twice at 35% bloom and again at 80% to 85% bloom, reduced fruit set without any fruit russeting in nectarine. Tergitol-TMN-6 at 7.5 mL·L–1 to 12.5 mL·L–1 reduced fruit set in `Empress' plum. CFO at 30 mL·L–1 was effective in blossom thinning of some peach cultivars. A combination of lime sulfur and CFO was not effective in blossom thinning of nectarine. Considering results from several orchards in different locations in the Pacific Northwest over 3 years, Tergitol-TMN-6 is an excellent blossom thinner for peach, nectarine, and plum at rates of 7.5 to 12.5 mL·L–1, sprayed at a spray volume of 1870.8 L·ha–1 when about 75% to 85% blooms are open.
Lutein Content in Sweetpotato Leaves
Authors: Menelaou Evdokia , Kachatryan Armen , Losso Jack N. , Cavalier Michael , La Bonte Don
Published: February 2019

Fresh leaves of 6 sweetpotato (Ipomoea batatas [L.] Lam.) genotypes, `Beauregard', `Bienville', L99–35, L00–8, L01–145, and L01–29, were characterized for lutein. Lutein is a carotenoid capable of delaying blindness-related macular degeneration. The content of lutein in sweetpotato ranged from 0.38 to 0.58 mg·g–1 fresh weight. Beta-carotene separated from lutein on high-pressure liquid chromatograms and when spiked in pure lutein extract did not interfere with lutein separation. High-resolution electro-spray ionization mass spectrometric analysis was used to confirm the presence of lutein in sweetpotato leaves. Stems were also characterized and found not to contain lutein. Our results showed that sweetpotato leaves are an excellent source of dietary lutein and surpass levels found in leafy crucifers. Leaves of sweetpotato and a related species are human food in some countries and may be a major source of lutein for commercial purposes.
Resistance of Olive Cultivars to the Defoliating Pathotype of Verticillium dahliae
Authors: Martos-Moreno Consuelo , López-Escudero Francisco Javier , Blanco-López Miguel Ángel
Published: February 2019

The resistance of 33 major olive cultivars to Verticillium dahliae was assessed in four experiments conducted under controlled conditions. Nine-month-old nursery olive plants were inoculated with a defoliating isolate (V117) of V. dahliae. Resistance was evaluated by assessing symptom severity using a 0–4 rating scale and estimating the area under disease progress curves with reference to the maximum value potentially reached over the assessment period (AUDPCP). The percentage of plants killed and that of plants that recovered from the disease were used as additional parameters for classifying the cultivars. Twenty-six of the 33 cultivars were found to be susceptible or extremely susceptible to the defoliating V. dahliae isolate. They exhibited values for AUDPCP higher than 45% with mortality higher than 37.5%. A second group of cultivars, which included `Cipresino', `Koroneiki', `Oblonga', and `Sevillenca', were classified as moderately resistant because they showed an important reduction of the final mean severity values and of values for AUDPCP that ranged from 23% to 42%. `Changlot Real', `Empeltre', and `Frantoio' were resistant to the defoliating isolate of V. dahliae. The resistance of `Empeltre' and `Frantoio', although previously reported, was consistently confirmed, because the two cultivars exhibited no dead plants and had very low values for AUDPCP and final disease. This is the first report of resistance of `Changlot Real' to Verticillium wilt based on ability of the plants to recover from infection and the absence of dead plants. These three cultivars will be useful for inclusion in Verticillium wilt-breeding programs.
Somatic Embryogenesis and Organogenesis in Magnolia dealbata Zucc. (Magnoliaceae), an Endangered, Endemic Mexican Species
Authors: Mata-Rosas Martín , Jiménez-Rodríguez Ángel , Chávez-Avila Victor M.
Published: February 2019

Plants of Magnolia dealbata were regenerated from zygotic embryos through somatic embryogenesis and direct organogenesis. Medium and incubation conditions were determinating factors for the development of morphogenetic responses. Photoperiodic exposure was a limiting factor in the general development of the explants, and incubation in darkness allowed their development. The highest formation of shoots per responding explant were obtained on woody plant (WP) medium supplemented with 13.3 μM or 22.2 μM 6-benzylaminopurine (BA) in combination with 2.26 μM or in absence of 2,4-dichlorophenoxyacetic acid (2,4-D) from which 2.5 shoots per explant were induced. Subcultures on WP medium, supplemented with polyvinylpyrrolidone (PUP) 40,000 1 g·L–1) avoided necrosis of explants. Somatic embryos were formed in 85% of explants cultivated on WP medium with 2,4-D (2.3 μM or 4.5 μM); 20% induced indirect embryogenesis and 65% formed direct somatic embryogenesis. The plants were transferred to soil to acclimatize under greenhouse conditions, achieving 90% survival. Somatic embryo conversion to plantlets was obtained with subculture on WP basal medium without growth regulators. In vitro culture can play a key role in the propagation and conservation of this endangered species.
Environmental Factors Influencing Germination in Seeded Seashore Paspalum
Authors: Shin J.S. , Raymer P. , Kim W.
Published: February 2019

Seashore paspalum (Paspalum vaginatum O. Swartz) is a perennial warm-season grass that is rapidly gaining popularity for use on golf courses and athletic fields. The first seeded cultivar of seashore paspalum was recently developed. Seed from the pilot production of this cultivar harvested in Oregon during 2002 by Turf-Seeds, Inc. demonstrated a high level of apparent seed dormancy with a tetrazolium test of 91% but a germination rate of less than 5% at room temperature. This seed was used in laboratory experiments to determine the effect of a number of environmental factors on germination response in this new turf species. Treatment factors are germination media, constant and alternating (night/day) temperatures, and light. A strong and significant effect of temperature on germination was observed. Total germination was increased at higher temperatures. At the same daytime temperature, seed germination under alternating temperature was better than germination at constant temperature. The effect of light on germination was significant at 20, 25, 30, 20/35 °C in water and at 25/35 °C in 0.2% KNO3 germination media. However, the effect of light on germination in KNO3 media was not significant at 35 °C constant and 20/30 °C alternating temperatures. Alternating temperature used in conjunction with KNO3 media reduced the requirement for light. The use of 0.2% KNO3 rather than water as the germination media increased germination in most temperature and light treatments. Based on our results, maximum germination percentage was obtained when seed was germinated at 35 °C constant or 20/35 °C alternating temperature. However, when we consider field application, 25/35 °C with light is more realistic condition in field. Therefore, recommended seed germination test condition is at 25/35 °C with KNO3 treatment.
Diurnal CO2 Assimilation Patterns in Nine Species of CAM-Type Succulent Plants
Authors: Lee Sang Deok , Kim Soon Jae , Jung Seung Il , Son Ki-Cheol , Kays Stanley J.
Published: February 2019

CO2 assimilation rate of Crassula hybrid `Himaturi', a succulent ornamental species with the crassulacean acid metabolism (CAM) photosynthetic pathway, was affected by light intensity (50, 100, 300 μmol·m–2·s–1), photoperiod (16/8, 8/16 h day/night), and temperature (30/25, 25/20 °C day/night). Maximum assimilation of CO2 occurred at 300 μmol·m–2·s–1 of diurnal irradiance, 16/8 h day/night photoperiod, and a day/night temperature of 30/25 °C. Diurnal CO2 assimilation patterns of nine succulent ornamental CAM species were evaluated (300 μmol·m–2 s–1, 35/25 °C day/night and a 16/8-h day/night photoperiod) for CO2 fixation. Of the nine ornamentals, Crassula `Himaturi' had the highest and Echeveria derembergii the lowest maximum CO2 absorption rate (13.0 vs 2.4 μmol kg–1·s–1), total nighttime (179.3 vs 13.4 mmol·kg–1), and 24 h total (200.6 vs 19.0 mmol·kg–1) absorption. Based on the CO2 assimilation patterns, the nine ornamentals were separated into two groups: 1) full CAM (Faucaria tigrina, Gasteria gracilis var. minima, Haworthia cymbiformis, and Haworthia fasciata); and 2) weakly CAM (Adromischus clarifolius, Crassula hybrids `Moonglow' and `Himaturi', E. derembergii, and Haworthia retusa).
Graft Compatibility Between Peach Cultivars and Prunus Rootstocks
Authors: Zarrouk Olfa , Gogorcena Yolanda , Moreno Maria Angeles , Pinochet Jorge
Published: February 2019

Trials were established at Aula Dei Experimental Station (EEAD-CSIC, Zaragoza, Spain) to assess graft compatibility between peach cultivars [Prunus persica (L.) Batsch] and new Prunus spp. rootstocks or selections. Peach cvs. `Catherina' and `Tebana' and nectarine cvs. `Big Top' and `Summergrand' were grafted on peach seedlings, plum rootstocks, almond × peach hybrids, and other interspecific rootstocks. Part of the evaluated material belongs to the EEAD-CSIC selection program, which has showed good adaptation to Mediterranean growing conditions. Other rootstocks such as Bruce, Evrica, Hiawatha, Ishtara, Tetra, and Krymsk-1 have been recently introduced in Spain. A peach and a plum source, GF 677 and Adesoto 101, respectively, were used as compatible reference rootstocks. Both are widely used for peach and nectarine production in the Mediterranean area.
Impact of Drought and Temperature on Growth and Leaf Gas Exchange of Six Bedding Plant Species Under Greenhouse Conditions
Authors: Niu Genhua , Rodriguez Denise S. , Wang Yin-Tung
Published: February 2019

The effect of drought on the growth and gas exchange of six bedding plant species—agastache [Agastache urticifolia (Benth.) O. Kuntze `Honeybee Blue'], dusty miller (Cineraria maritima L. `Silverdusty'), petunia (Petunia ×hybrida `Wave Purple'), plumbago (Plumbago auriculata Lam. `Escapade'), ornamental pepper (Capsicum annuum L. `Black Pearl'), and vinca [Catharanthus roseus (L.) G. Don `Titan']—was quantified under greenhouse conditions. Seeds were sown in January and seedlings were grown in the greenhouse until 18 Apr., when two irrigation treatments—drought (D, ≈18% volumetric moisture content at reirrigation) and control (C, ≈25% volumetric moisture content at reirrigation)—were initiated. Leaf net photosynthetic rate (Pn), stomatal conductance (gs), and transpiration (E) were determined in response to a range of substrate moisture content (from ≈5% to 30% by volume) and temperature (from 20 °C to 40 °C). Dry weight of agastache, ornamental pepper, and vinca was unaffected by drought, whereas that of other species was reduced. Leaf area of plumbago and height of plumbago and vinca were reduced by drought. As substrate moisture content decreased from 25% to 10%, Pn, E, and gs decreased linearly in all species except petunia and plumbago. Leaf net photosynthetic rate of all species declined as leaf temperature increased from 20 °C to 40 °C. In contrast, E of all species, except petunia, increased as temperature increased. Transpiration rate of petunia increased as temperature increased from 20 °C to 30 °C, and then decreased between 30 °C and 40 °C. Although petunia had the highest Pn among the tested species, its Pn and gs declined more rapidly compared with the other species as temperature increased from 20 °C to 40 °C or as substrate moisture content decreased, indicating that petunia was most sensitive to high temperature and drought.
Effect of Heating Fruit on Cell Size and Sugar Accumulation in Melon Fruit (Cucumis melo L.)
Authors: Kano Yasutaka
Published: February 2019

To investigate the relationship between cell size and sugar accumulation, fruit of the melon was heated during the early stage of the growing period. The minimum air temperature in the heating apparatus was ≈10 °C higher than the ambient air temperature, and the weight of the heated fruit was greater than that of the control fruit. The number of rectangular parallelepiped (7-mm-long sample serially collected beginning at one end of the 10-mm-wide strip removed from the 10-mm-thick disk at the maximum transverse diameter of the fruit to the opposite end) with cells larger than 200 μm in the heated fruit at 17 days after anthesis (DAA, the end of heating treatment) was much larger that of the control fruit. The mean cell size in the heated fruit at 17 DAA was larger than that of the control fruit. Mean sucrose content of the heated fruit on 40 DAA was larger than the level in the control fruit. Higher fruit temperatures in melons covered with heating apparatus results in the predominance of larger cells and increased accumulation of sucrose in the fruit.
Fruit Size and Yield of Mandarins as Influenced by Spray Volume and Surfactant Use in NAA Thinning
Authors: Stover Ed , Ciliento Scott , Myers Monty , Boman Brian , Jackson John , Still Max
Published: February 2019

Six trials were conducted to determine whether lower spray volumes or inclusion of different surfactants would permit adequate thinning of mandarin hybrids (Citrus reticulata hybrids) at a much lower cost per hectare. Sprays were applied using a commercial airblast orchard sprayer during physiological drop when fruitlets averaged 8 to 16 mm in diameter. Surfactant was always included at 0.05% v/v. NAA always reduced fruit per tree, increased fruit size, and decreased production of smallest size fruit. However, in only three experiments, contrast of all NAA treatments vs. controls indicated increased production of the largest (80–100 fruit per carton) and most valuable fruit. In four of five experiments, comparison of spray volumes of 600 (only examined in three of four experiments), 1200, or 2300 L·ha–1 demonstrated significant fruit size enhancement from all NAA applications. Most individual NAA treatments resulted in fewer fruit per tree, but there were no statistically significant differences between NAA treatments at different spray volumes. In only one of the four experiments, there was a marked linear relationship between spray volume and fruit per tree, yield, mean fruit size, and production of largest fruit sizes. The effects of surfactants (Activator, a nonionic, Silwet L-77, and LI-700) on NAA thinning were tested in both `Murcott' and `Sunburst'. In comparisons between Silwet L-77 and Activator surfactant, one experiment with `Murcott' showed greater fruit per tree and yield reduction from using Silwet, but with a smaller increase in production of largest fruit sizes, whereas in another `Murcott' experiment, Silwet L-77 reduced numbers of smaller fruit size with no increase in production of larger fruit. Based on these findings, current recommendations for NAA thinning of Fla. mandarins are use of spray volume of ≈1100–1400 L·ha–1 on mature trees with proportionally lower volume on smaller trees. These data appear to support use of a nonionic surfactant rather than other tested surfactants in NAA thinning of Florida mandarins. Because experience with NAA thinning of Florida citrus is limited, it is only recommended where the disadvantages of overcropping are perceived to substantially outweigh the potential losses from overthinning.
Fe-EDDHA Alleviates Chlorosis in `Concord' Grapevines Grown at High pH
Authors: Smith Brandon R. , Cheng Lailiang
Published: February 2019

`Concord' grapevines (Vitis labruscana Bailey) can readily develop iron deficiency-induced leaf chlorosis when grown on calcareous or high pH soils. Iron (Fe) chelates are often applied to the soil to remedy chlorosis but can vary in their stability and effectiveness at high pH. We transplanted own-rooted 1-year-old `Concord' grapevines into a peat-based medium adjusted to pH 7.5 and fertigated them with 0, 0.5, 1.0, 2.0, or 4mg·L–1 Fe from Fe-EDDHA [ferric ethylenediamine di (o-hydroxyphenylacetic) acid] to determine the effectiveness of this Fe chelate for alleviating Fe deficiency-induced chlorosis at high pH. Vines were sampled midseason for iron, chlorophyll, CO2 assimilation, and photosystem II quantum efficiency (PSII) and at the end of the season for leaf area, dry weight, and cane length. We found that leaf total Fe concentration was similar across all treatments, but active Fe (extracted with 0.1 n HCl) concentration increased as the rate of Fe-EDDHA increased. Chlorophyll concentration increased curvilinearly as applied Fe increased and was highly correlated with active Fe concentration. CO2 assimilation, stomatal conductance, and PSII were very low without any supplemental Fe and increased rapidly in response to Fe application. Total leaf area, foliar dry weight, and cane length all increased as Fe application increased to 1 mg·L–1 Fe, but above this rate, a further increase in Fe did not significantly increase growth. Our results demonstrate that Fe-EDDHA is very effective in alleviating Fe deficiency-induced leaf chlorosis in `Concord' grapevines grown at high pH, which provides a foundation for continuing research related to the optimum rate and timing of application of Fe-EDDHA in `Concord' vineyards on calcareous soils. Compared with total Fe, leaf “active Fe” better indicates the actual Fe status of `Concord' vines.
Postharvest Quality and Ripening of Dwarf Brazilian Bananas (Musa sp.) after X-ray Irradiation Quarantine Treatment
Authors: Wall Marisa M.
Published: February 2019

Fruit quality and ripening of Dwarf Brazilian bananas (Musa sp., group AAB) were determined after x-ray irradiation for disinfestation of quarantine pests. The proximal and distal hands from winter- and summer-harvested bunches were treated with irradiation doses of 0, 200, 400, 600, or 800 Gy, stored for 7 days at 14 °C, and ripened at 20 °C. Irradiation did not extend banana shelf life or affect soluble solids content, but titratable acidity decreased with increasing dose. Starch and total sugar concentrations were similar for control and irradiated fruit at all doses. However, sucrose contents decreased linearly as dose increased, whereas glucose and fructose concentrations increased, indicating an acceleration of sucrose hydrolysis in treated bananas. Irradiation retarded peel softening but not pulp softening for winter-harvested fruit and had a minimal effect on peel and pulp firmness of summer-harvested fruit. For irradiated fruit, the respiratory climacteric rates decreased relative to control fruit, but CO2 and ethylene production increased 1 day after irradiation stress. Proximal fruit (more mature) had higher respiration rates and produced more ethylene than distal fruit (less mature) after irradiation, but differences in physiological maturity between hands did not affect soluble solids, titratable acidity, starch, or total sugar content of ripe fruit. Bananas from distal hands treated with 800 Gy irradiation developed peel injury when harvested in either the winter or summer months. Summer-harvested fruit also were damaged at the 600-Gy dose for distal fruit only. Treatment of fruit from the proximal half of bunches at doses ≤600 Gy would ensure visual quality while providing quarantine security for Dwarf Brazilian bananas.
Establishing Lettuce Leaf Nutrient Optimum Ranges Through DRIS Analysis
Authors: Hartz Timothy K. , Johnstone P. R. , Williams E. , Smith R.F.
Published: February 2019

A survey of 78 commercial iceberg and romaine lettuce (Lactuca sativa L.) fields in the coastal valleys of central California was conducted in 2004–2005. Whole leaf samples were collected at early heading and again within 1 week of harvest. Diagnosis and Recommendation Integrated System (DRIS) leaf concentration norms were calculated for N, P, K, Ca, Mg, S, B, Zn, Mn, Fe, and Cu. Iceberg and romaine lettuce had sufficiently similar leaf nutrient concentrations that the data were combined in the DRIS calculations. Optimum leaf nutrient ranges were developed using data from high-yield fields in which all nutrients were in balance according to the DRIS approach. The DRIS-derived optimum ranges for K and Ca were substantially lower than previously published leaf sufficiency ranges, whereas for the other nutrients, the DRIS optimum ranges were in close agreement. Cu was the nutrient most frequently below the optimum range in low-yield fields. Comparison of leaf nutrient concentrations with soil nutrient availability and grower fertilization practices suggested that significant improvement in fertilizer management was possible.
Effects of Polypropylene Groundcover on Soil Nutrient Availability, Sweet Cherry Nutrition, and Cash Costs and Returns
Authors: Yin Xinhua , Seavert Clark F. , Turner Janet , Núñez-Elisea Roberto , Cahn Helen
Published: February 2019

The impacts of synthetic polypropylene groundcover in the row area of young sweet cherry (Prunus avium L.) trees (Regina on Gisela 6) on soil nutrient availability, tree mineral nutrition and productivity, and cash costs and returns were investigated on a Van Horn fine sandy loam soil at Hood River, Ore., from 2001 to 2005. Treatments included 2.44-m wide synthetic fabric groundcover made of black, woven polypropylene over the row area of cherry trees and no groundcover but with herbicide applications in the row area with the same width as the polypropylene groundcover. Soil-available NO3
−, P, K, Ca, Mg, S, B, Zn, Mn, and Cu contents in 0 to 30 cm in August did not differ significantly between the cover and no cover treatments in any year except 2005, when soil N and K levels were lower with polypropylene cover. Leaf N concentration in August was enhanced by 11% to 19% each year in the polypropylene cover treatment. However, leaf P concentration was lowered by 19% to 37% with polypropylene cover each year; and leaf Ca and Mg concentrations were reduced by 9% to 13% and 6% to 24%, respectively, as a result of polypropylene cover in 3 of 5 years. Reduced leaf P, Ca, and Mg concentrations in the cover treatment were attributed to the diluting effects of enhanced tree growth and fruit yield. Cumulative cash costs for the orchard within the first 4 years before fruit production were $5246/ha higher with polypropylene cover relative to no cover. However, these costs were offset quickly by increased returns from enhanced fruit yields. In the long-term, more fertilizers may need to be applied on polypropylene groundcovered trees to compensate for the enhanced tree growth and fruit production.
G-435 and ARS 96-138, Pink-fruited Blueberry Selections
Authors: Ehlenfeldt Mark K. , Finn Chad E.
Published: February 2019

G-435 and ARS 96–138 are two pink-fruited blueberry selections developed by the Agricultural Research Service of the U.S. Department of Agriculture. G-435, a tetraploid, is predominantly Vaccinium corymbosum L. (highbush blueberry) with a mixture of other Vaccinium species germplasm in its ancestry. It has been evaluated in New Jersey and Michigan. ARS 96–138 is a hexaploid that is half V. ashei Reade (rabbiteye blueberry) and half synthetically derived, hexaploid, highbush-type germplasm. It has been evaluated in New Jersey and Oregon. ARS 96–138 was partially derived from a pink-fruited sibling of G-435; thus, the two selections are related, although they possess different ploidy levels. They are released as germplasm for further evaluation, breeding, and possible commercialization. They represent a novel fruit color in blueberry that is of interest to the landscape nursery business.
19th and 20th Century Plant Hunters
Authors: Stoner Allan , Hummer Kim
Published: February 2019

The latter part of the 19th and the first several decades of the 20th century can be described as a “golden age” for plant exploration and collecting. During the initial years of this period, agricultural scientists from the United States and elsewhere devoted considerable resources to collecting potential new crops for farmers as well as superior plants or cultivars of the species that farmers were already growing. Over time, there was a shift toward collecting unadapted germplasm, or raw material that possessed traits that plant breeders and other scientists could use for cultivar improvement and other types of research. Although many institutions and individuals were involved in plant collecting during this period, the creation of the U.S. Department of Agriculture (USDA) Office of Seed and Plant Introduction in 1898, resulted in the largest single program devoted to plant exploration. This office employed many individuals, including David Fairchild, P.H. Dorsett, Frank Meyer, Walter Swingle, and Wilson Popenoe. These and many other individuals collected—and introduced into the United States—seeds and plants of thousands of fruits, vegetables, nuts, ornamentals, cereals, forages, oilseeds, and other types of crops. Although the mission of most of the plant explorations during this period was to collect any plants that appeared interesting or potentially useful, others focused on collecting targeted species. Much of the material collected during this era is still maintained by the U.S. National Plant Germplasm System (NPGS), and much more of it shows up in the pedigrees of cultivars grown by farmers and gardeners today. In addition to collecting plants for immediate and future use, scientists of this era, such as Nicolai I. Vavilov and Jack Harlan, contributed greatly to the understanding of the evolution of plants and plant genetic diversity, and the interdependence of plants and civilization.
Strawberry Growth and Productivity in Fumigated Compared to Compost-amended Production Systems
Authors: Leandro Leonor F.S. , Ferguson Lisa M. , Louws Frank J. , Fernandez Gina E.
Published: February 2019

Strawberry (Fragaria ×ananassa Duchnesne) growth and productivity were compared in fumigated and nonfumigated production systems. Strawberry transplants grown in potting mix amended with Trichoderma hamatum (Bonord.) Bainier, strain T382, Trichoderma harzianum Rifai, strain T22, or untreated, were planted in field plots treated with compost, compost amended with T. hamatum strain T382, Telone-C35, or not treated. Plants were sampled throughout the growing season, and dry weights of roots, crowns, leaves, flowers and fruit, leaf area, and total and marketable yield were determined. Trichoderma amendments to the potting mix improved plant dry weight and leaf area of strawberry transplants in the first year and suppressed root rot incidence in the second year but did not affect plant growth or disease incidence once the plants were set in the field. Field plants in fumigated plots had greater root, leaf, and crown dry weights, leaf area, and yield compared with plants in the other soil treatments. We conclude that Trichoderma amendments (1) alone had little benefit to plug plant growth and (2) in combination with compost, had no benefit to strawberry plant growth in the field. The task remains to develop a reliable and sustainable strawberry production system that does not rely on chemical fumigants.
Evaluating the Role of Ethnicity on Gardening Purchases and Satisfaction
Authors: Dennis Jennifer H. , Behe Bridget K.
Published: February 2019

In Sept. 2004, an Internet study was conducted to evaluate and determine differences in gardening participation, purchases, and levels of satisfaction and regret by ethnic background. Consumers were asked to identify their participation in seven gardening activities and about the purchase of 12 gardening product categories. The sample was stratified by income and age. The number of differences in garden-related activity participation and purchases decreased as income level increased across ethnic groups. At every income level, persons of Caucasian descent had a higher satisfaction average score and factor score and higher regret mean score and factor score. This indicated that Caucasians did experience greater satisfaction and less regret than persons of other ethnic backgrounds, regardless of income. For marketers, this shows a heterogeneous market at lower-income levels and a more homogeneous market at upper-income levels. Ethnicity could be used as a basis for market segmentation, and differences are indeed present.
Turf Species Affects Establishment and Growth of Redbud and Pecan
Authors: Griffin Jason J. , Reid William R. , Bremer Dale J.
Published: February 2019

Establishment and growth of eastern redbud (Cercis canadensis L.) and pecan [Carya illinoinensis (Wangenh.) K. Koch] were studied where soil surfaces were either covered with each of three common turfgrass species or maintained free of vegetation by the use of an herbicide or an organic mulch layer. Turf species included two cool-season grasses, tall fescue (Festuca arundinacea Schreb.) and Kentucky bluegrass (Poa pratensis L.), and the warm-season bermudagrass [Cynodon dactylon (L.) Pers.]. After two growing seasons, tree caliper of both species was 100% greater in turf-free plots compared with trees in the cool-season grass plots. Root weight of pecans increased nearly 200% when turf was eliminated, and redbud root weight increased nearly 300%. Top weight of redbuds increased 300% and pecans increased 200% when turf was eliminated. Total leaf weight of both species was 300% greater in the turf-free plots, and leaf area increased 200% in both species. Net photosynthesis of redbud trees tended to be higher in the plots without turfgrass, and cool-season grasses inhibited photosynthesis to a greater extent than the warm-season grass. Foliar tissue analysis revealed that nitrogen (N) and potassium (K) were the only elements that increased in concentration when turf was eliminated. However, nutrient concentrations in all treatments were within recommended standard ranges. The results suggest that landscape tree establishment and growth are greatly inhibited by the presence of cool-season turfgrasses and that the inhibition may be more complicated than resource competition.
Comparison of the Allelopathic Potential of Leguminous Summer Cover Crops: Cowpea, Sunn Hemp, and Velvetbean
Authors: Adler Michael J. , Chase Carlene A.
Published: February 2019

The phytotoxicity of aqueous foliar extracts and ground dried residues of sunn hemp (Crotalaria juncea L.), cowpea [Vigna unguiculata (L.) Walp. cv. Iron Clay], and velvetbean [Mucuna deeringiana (Bort) Merr.] to crop and weed germination and growth was evaluated to compare the allelopathic potential of the cover crops. By 14 days after treatment (DAT), goosegrass [Eleusine indica (L.) Gaertn.] germination with 5% aqueous extracts of all cover crops (w/v fresh weight basis) was similar and greater than 75% of control. However, with the 10% extracts, goosegrass germination was lowest with cowpea extract, intermediate with velvetbean extract, and highest with sunn hemp extract. Livid amaranth (Amaranthus lividus L.) germination declined to ≈50% with cowpea and sunn hemp extracts and even lower to 22% with velvetbean extract. The suppression of livid amaranth germination was greater with the 10% extracts than the 5% extracts. Bell pepper (Capsicum annuum L.) germination was unaffected by velvetbean extract, inhibited more by the 5% cowpea extract than the 10% extract, and was also sensitive to the 10% sunn hemp extract. All cover crop extracts resulted in an initial delay in tomato (Lycopersicon esculentum Mill.) germination, but by 14 DAT, inhibition of germination was apparent only with cowpea extract. The phytotoxicity of ground dried residues of the three cover crops on germination, plant height, and dry weight of goosegrass, smooth amaranth (A. hybridus L.), bell pepper, and tomato was evaluated in greenhouse studies. Goosegrass germination was inhibited in a similar manner by residues of the three cover crops to 80% or less of control. Smooth amaranth germination, plant height, and dry biomass were more sensitive to sunn hemp residues than to cowpea and velvetbean residues. Bell pepper germination, plant height, and dry weight were greater than 90% of control except for dry weight with cowpea residue, which was only 78% of control. The greatest effect of cover crop residue on tomato occurred with dry weight, because dry weights with cowpea and sunn hemp were only 76% and 69% of control, respectively, and lower than with velvetbean. There was more evidence of cover crop phytotoxicity with the weed species than with the crop species and cowpea extracts and residue affected all species more consistently than those of sunn hemp and velvetbean.
Somatic Embryogenesis in Habanero Pepper (C. chinense Jacq.) From Cell Suspensions
Authors: Zapata-Castillo Patricia Yolanda , Flick Adriana-Canto , López-Puc Guadalupe , Solís-Ruiz Anabel , Barahona-Pérez Felipe , Santana-Buzzy Nancy , Iglesias-Andreu Lourdes
Published: February 2019

To induce the somatic embryogenesis of Habanero pepper, different culture media and different types of explants (node, internode, hypocotyl, half seeds, and fruit segments) were evaluated. For the induction of embryogenic callus, 9.05 μm of 2,4-dichlorofenoxiacetic acid, 3% sucrose, and 0.8% gelrite were added to the basic MS medium over a period of 30 days at 25 ± 2 °C under continuous light (40–50 μmol·m2·s−1). Once the callus formed, they were transferred to liquid medium using the same induction formulation. Somatic embryogenesis only occurred from explants of hypocotyl and in the presence of 3.4 μm thidiazuron. This constitutes the first proposal of a protocol for the “induction of somatic embryogenesis in Habanero pepper (Capsicum chinense Jacq.) from cell suspensions.”
Dwarf Bermudagrass Tolerance to Preemergence Herbicides
Authors: McCullough Patrick E. , Whitwell Ted , McCarty Lambert B. , Liu Haibo
Published: February 2019

Preemergence herbicides are applied to prevent summer annual weed infestations in turf, but safety to dwarf-type bermudagrass golf greens has not been determined for many of these materials. Field experiments tested ‘TifEagle’ bermudagrass response to bensulide at 11.2 kg·ha−1 (a.i.), dithiopyr at 0.56 kg·ha−1 (a.i.), napropamide at 2.2 kg·ha−1 (a.i.), oxadiazon at 2.2 kg·ha−1 (a.i.), oxadiazon plus bensulide at 1.7 + 6.7 kg·ha−1 (a.i.), and pendimethalin at 1.7 kg·ha−1 (a.i.). All herbicides reduced root mass from the nontreated, but only losses incited by oxadiazon plus bensulide were acceptable (less than 20%). Dithiopyr, napropamide, and pendimethalin delayed spring greenup in 2003 and 2004, whereas oxadiazon plus bensulide delayed spring greenup in 2004. In greenhouse experiments, ‘TifEagle’ bermudagrass root mass was reduced 19% to 37%, 30% to 33%, 4% to 26%, 28% to 37%, and 24% to 30% from various rates of bensulide, dithiopyr, napropamide, and pendimethalin, respectively. Oxadiazon and oxadiaxon plus bensulide reduced root mass by only 2% to 15% and 15% to 22%, respectively. In another experiment, oxadiazon plus bensulide at 1.7 + 6.7 kg·ha−1 did not injure shoots or roots of ‘Champion’, ‘FloraDwarf’, ‘MiniVerde’, ‘Tifdwarf’, or ‘TifEagle’ bermudagrass. Overall, dwarf-type bermudagrass golf greens do not appear to tolerate mitotic inhibitor preemergence herbicides, whereas oxadiazon or oxadiazon plus bensulide caused minimal injury.
Adventitious Shoot Regeneration from In Vitro Leaves of Formosan Sweetgum (Liquidambar formosana L.)
Authors: Xu L. , Liu G.F. , Bao M.Z.
Published: February 2019

Plantlets were regenerated from in vitro-grown leaf explants of five genotypes of Liquidambar formosana on WPM basal medium supplemented with different concentrations of TDZ and NAA. With the addition of 0.27 μm NAA, regeneration efficiency was increased by 2- to 4-fold over that with TDZ alone. Lower concentrations of TDZ (0.45–2.27 μm) were beneficial for regenerating shoot clusters. Four genotypes (P2, P6, P9, and P11) showed high regeneration rates (up to 90%), whereas genotype P13 showed a low capability for shoot regeneration on all media tested (<35%). For all five genotypes, the optimum medium for inducing adventitious shoots was WPM supplemented with 1.14 μm TDZ and 0.27 μm NAA, on which regeneration rate ranged from 72.6% to 89.5% and adventitious shoot clusters per regenerating leaf explant ranged from 2.63 to 3.11 in four genotypes (P2, P6, P9, and P11), while for P13, the regeneration rate and number of shoot clusters per regenerating explant were 23% and 1.39, respectively. Transfer of shoot clusters to WPM basal medium containing 0.54 μm NAA, 2.22 μm BA, and 1.44 μm GA3, resulted in shoot elongation. All the elongated shoots were rooted on WPM supplemented with 9.84 μm IBA, and plantlets were transplanted to soil successfully.

Chemical names used: 6-benzyladenine (BA), gibberellic acid (GA3), indole-3-butyric acid (IBA), 1-naphthalene acetic acid (NAA), plant growth regulator (PGR), thidiazuron (TDZ), woody plant medium (WPM).
Stimulation of Plant Growth by (3-Methoxyphenyl)acetonitile Applied as a Foliar Spray In Vivo or as a Medium Amendment In Vitro
Authors: Vaughn Steven F. , Berhow Mark A. , Tisserat Brent
Published: February 2019

Meadowfoam (Limnanthes alba Hartweg ex. Benth.) seedmeal, a coproduct of oil extraction from meadowfoam seeds, has been found to increase the growth of greenhouse plants when added to the growing medium. (3-Methoxyphenyl)acetonitrile (3-MPAN) is a biologically active glucosinolate degradation compound previously identified at high levels in meadowfoam seedmeal. 3-MPAN was tested as a foliar spray at several concentrations (0 μm, 0.18 mm, 0.37 mm, 0.73 mm, 2.2 mm, and 7.3 mm) on lime basil (Ocimum basilicum L.), spearmint (Mentha spicata L.), cuphea (Cuphea lanceolata L.), and French marigold (Tagetes patula L.) seedlings grown in the greenhouse. 3-MPAN increased the fresh and dry weights of all four species tested. However, this effect was dose-dependent among species with spearmint growth higher at all 3-MPAN application rates, whereas basil growth was promoted at only the 2.2-mm rate. 3-MPAN increased the tissue concentrations of the secondary compound (−)-carvone at the 7.3-mm application rate. In addition, 3-MPAN added to sterile nutrient media stimulated the growth of spearmint plants in vitro. These results indicate that 3-MPAN may have applicability as a postemergent growth stimulant for a wide variety of plants.
The Effect of Repeat Annual Applications of Prohexadione–calcium on Fruit Set, Return Bloom, and Fruit Size of Apples
Authors: Greene Duane W.
Published: February 2019

Prohexadione–calcium (ProCa) is used routinely in orchards to control vegetative growth and to reduce the shoot blight phase of fire blight. This communication reports on multiple-year applications of ProCa with special emphasis on treatment effects on fruit set, fruit size, and return bloom. Increased fruit set was confirmed from high rates of ProCa above 125 mg·L−1. The increase in fruit set was attributed primarily to a reduction of abscission during June drop rather than an increase in initial set. ProCa decreased fruit weight in some instances. Part of this reduction could be attributed to increased fruit set. However, the large reduction in fruit weight at harvest could only be explained by a direct effect of ProCa when used at high rates. When ProCa was applied as a concentrate spray at 250 mg·L−1, terminal growth was reduced comparable to the application made as a tree row volume dilute spray (1×). However, fruit set was increased when the spray volume in which ProCa was delivered was reduced to 4×. A range of ProCa rates was used on ‘Mutsu’. An initial application rate of 42 mg·L−1 followed by similar subsequent rates controlled growth comparably to higher initial and total rates, yet low rates had no effect on fruit weight or return bloom. Low rates of ProCa appear to be effective at controlling vegetative growth yet appear to have minimal side effects. High rates, especially those intended to reduce fire blight, come with the risk of increased fruit set and reduced fruit size and return bloom.
Storage Life and Deterioration of Intact Cantaloupe (Cucumis melo L. var. reticulatus) Fruit Treated with 1-Methylcyclopropene and Fresh-cut Cantaloupe Prepared from Fruit Treated with 1-Methylcyclopropene Before Processing
Authors: Jeong Jiwon , Brecht Jeffrey K. , Huber Donald J. , Sargent Steven A.
Published: February 2019

A study was conducted to determine the influence of the ethylene action inhibitor, 1-methylcyclopropene (1-MCP), on the shelf life and deterioration during storage at 5 °C of intact netted muskmelon (Cucumis melo L. var. reticulatus) fruit and fresh-cut cubes prepared from those fruit. ‘Durango’, ‘Magellan’, and ‘7920’ fruit (3/4 to full-slip stage) were treated with 1-MCP (1.0 μL·L−1) for 24 h at 20 °C. Preliminary research with ‘Athena’ muskmelon had shown that the more physiologically advanced distal pericarp tissue developed significantly more watersoaking than the less advanced proximal and center portions during 5 °C storage; therefore, after treatment with 1-MCP and cooling to 5 °C, the center portions of the fruit were used to prepare the fresh-cut samples. Fresh-cut cubes and intact fruit were stored for 12 d at 5 °C. Intact fruit of all tested cultivars responded to 1-MCP application with improved firmness retention during storage, but no watersoaking was observed in intact fruit. The effect of 1-MCP treatment on the firmness retention and watersoaking of fresh-cut cubes from the different cultivars was inconsistent. Exposure of muskmelon fruit to 1-MCP did not significantly influence the flesh color or soluble solid contents of either intact fruit or fresh-cut cubes during storage at 5 °C.
An Efficient Tissue Culture Regeneration System for Georgia Plume, Elliottia racemosa, a Threatened Georgia Endemic
Authors: Woo Seong Min , Wetzstein Hazel Y.
Published: February 2019

Georgia plume, Elliottia racemosa Muhlenb. ex. Elliott, is an extremely rare small tree or shrub endemic to Georgia, which is being severely affected by habitat loss and lack of sexual recruitment. In vitro plant regeneration of Georgia plume has not been previously reported and may be a method for the conservation and propagation of this threatened species. Studies evaluated the effects of sterilization methods, explant types, medium composition, and light environment on plant regeneration. An efficient plant regeneration system was developed in which adventitious shoot buds were induced using young, expanding leaf explants placed on an induction medium supplemented with 10 μm thidiazuron and 5 μm indole-3-acetic acid with Gamborg's B5 salts. Shoot elongation was promoted on a medium with 25 μm (2-isopentenyl) adenine incorporated into Woody Plant Medium. In vitro rooting studies evaluated continuous and pulse auxin treatments and ex vitro rooting trials after KIBA (indole-3-butric acid, potassium salt) dips. A 5-day pulse treatment on 100 or 150 μm indole-3-butyric acid produced ≈90% rooting of shoots with greater shoot and root dry weight than other pulse times. High rooting frequencies were obtained under in vitro and ex vitro conditions with over 85% survival of plantlets transferred to greenhouse conditions. The culture protocol was found to be effective with material collected from mature specimens in the wild from divergent populations. Tissue culture appears to be a promising approach for the propagation and conservation of this rare and threatened plant.