Browse

You are looking at 1 - 10 of 28,682 items for

  • All content x
Clear All
Open access

Renee T. Threlfall, John R. Clark, Aubrey N. Dunteman, and Margaret L. Worthington

Breeding and release of new fresh-market blackberries (Rubus subgenus Rubus Watson) is vital for competitive markets to address evolving changes and production challenges. Physical, composition, and sensory attributes of six University of Arkansas (UA) System Division of Agriculture blackberry cultivars (Caddo, Natchez, Osage, Ouachita, Ponca, and Prime-Ark® Traveler) were evaluated to identify marketable attributes. The consumer sensory study (n = 81) had two elements: a visual evaluation of displayed blackberries and an appearance, tasting, and firmness evaluation of the six cultivars using a 9-point verbal hedonic liking scale and a 5-point just about right (JAR) scale. Consumers preferred large blackberries when presented with individual berries of varying sizes and clamshells filled with equal weights of small or large blackberries. The largest of the six cultivars, Natchez and Caddo, were scored favorably for size and shape. Consumers also preferred clamshells with little to no red drupelet reversion, a postharvest disorder where black drupelets on the blackberry turn red during or after cold storage. Consumers did not detect differences in the appearance or firmness of the cultivars and rated the firmness of all cultivars favorably on the JAR scale. The physical and composition attributes of the six cultivars were within commercially acceptable ranges (soluble solids = 9% to 10%, pH = 3.1–3.8, titratable acidity = 0.6% to 1.4%, and berry weight = 6–10 g). ‘Ponca’, ‘Osage’, ‘Caddo’, and ‘Natchez’ were all rated highly for sweetness, sourness, overall flavor, and overall impression. ‘Ponca’ was rated high for sweetness, overall flavor, and overall impression and had 10.4% soluble solids, 0.82% titratable acidity, and a 12.8 soluble solids/titratable acidity ratio. The identification of these marketability attributes of fresh-market blackberries will provide information to advance breeding efforts for fruit with commercial potential.

Open access

Yulia A. Kuzovkina and Lorenzo Vietto

The International Poplar Commission, FAO UN, was appointed to serve as the International Cultivar Registration Authority for the genus Salix in 2013 (). Eight hundred and fifty-four cultivar epithets were included in the Checklist for Cultivars of Salix (Willow) to provide the baseline for the formal registration of new cultivars epithets (, ). Twenty-six new cultivar epithets have been registered since 2016 and included in the .

Open access

Eric T. Wolske, Bruce E. Branham, and Kevin J. Wolz

The shade tolerance of black currants (Ribes nigrum cv. Consort) was studied by measuring the growth and productivity of mature plants in the field for three seasons under full sun or artificial shade netting in Urbana, IL. Shade treatments reduced photosynthetically active radiation (PAR) from 37% to 83%. Yield was not reduced in shade levels up to 65% but decreased by as much as 66% under 83% shade. Shade had minimal effect on stem rejuvenation in the first 2 years, but reduced rejuvenation in the third year from 14 new stems in full sun to eight new stems in 83% shade. Stem diameter decreased 8% to 19% with 83% shade, whereas no changes were observed in up to 65% shade. Plant height increased 5% to 8% from open sun to 83% shade. Specific leaf weight decreased and leaf area increased with shade. Powdery mildew severity increased with shade, and disease-resistant cultivars should be considered for understory crops. Our results indicate that growth and productivity of black currants can be maintained in moderate shade but shade levels beyond 65% will significantly reduce agronomic performance.

Open access

Kim D. Bowman and Ute Albrecht

Modern citrus nursery production makes use of potted-tree propagation in greenhouses. Supplemental lighting is one method by which nursery tree growth and profitability may be significantly improved, but limited specific information is available. Five replicated experiments were conducted to determine the utility and effects of increasing daylength during the winter months by supplemental illumination from light-emitting diode (LED) or high-pressure sodium (HPS) lights in citrus nursery propagation. Studies used ‘Valencia’ sweet orange scion, the most common citrus cultivar grown in Florida, and the commercially important rootstocks sour orange, ‘Cleopatra’ mandarin, ‘US-812’, ‘US-897’, ‘US-942’, and ‘US-1516’. Comparisons used the three common types of citrus rootstock propagation: seed, stem cuttings, and micropropagation. Six responses were measured in the lighting experiments, including vegetative growth before budding, scion bud survival, and scion bud growth after budding. Supplemental HPS or LED light to extend daylength to 16 h in the citrus nursery during short-day winter months was observed to be effective in increasing unbudded rootstock liner growth and ‘Valencia’ scion growth on all rootstocks and propagation types. Generally, the positive effect on vegetative growth from an increased daylength was stronger with the HPS light than with LED light, while increasing daylength with LED light, but not HPS light, provided some increased bud growth initiation. Use of HPS or LED supplemental lighting to extend daylength offers significant growth advantage for the citrus nursery industry in winter.

Open access

Ivette Guzman, Krystal Vargas, Francisco Chacon, Calen McKenzie, and Paul W. Bosland

This study investigated the diversity of carotenoids and phenolics in germplasm from three Capsicum (chile pepper) species, Capsicum annuum, Capsicum baccatum, and Capsicum chinense. Lutein, a yellow-pigmented carotenoid, and phenolics, a group of secondary metabolites, are reported to have health-promoting properties. The germplasm studied matured to a yellow color. The hypothesis was that all yellow fruits would contain either the carotenoid lutein, a yellow pigment, or a large amount of phenolics, a group of secondary metabolites that may be yellow among other colors. Thirty-one Capsicum accessions were grown in the field over a period of two seasons. On a dry weight (DW) basis, lutein ranged from 0.14 to 94.2 μg·g−1, and total phenolics ranged from 5.79 to 15.01 mg·g−1. No lutein was detected in one accession and β-carotene, another health-promoting compound, was lacking in four accessions. Accessions were grouped into four groups according to a principal component analysis plot. Results from this study indicate that in only nine accessions, lutein represented at least 50% of the total carotenoid amounts in each accession. These accessions are desirable not only as a source of dietary lutein, a natural yellow pigment, but also as genetic material that can be used to breed for higher lutein Capsicum. Therefore, yellow color is not a good indicator of lutein content and phytochemical analysis is required to determine the content of health-promoting compounds.

Open access

Evan Elford, Jim Todd, Peter White, Rachel Riddle, John O’Sullivan, and Rene Van Acker

To foster development of Ontario commercial tigernut (Cyperus esculentus var. sativus) production, this study was conducted to identify cultural management practices that increase tuber yields. The agronomic practices of field preparation (hilled vs. not hilled), regular irrigation vs. natural rainfall, varying rates of nitrogen (N) fertility, and early season weed management were evaluated. Irrigation had no significant impact on total fresh weight, dry weight, and marketable yield over 2 growing seasons. Similarly, yields from plants grown in hilled rows vs. flat beds over two seasons showed no significant differences. Tigernut yields did not show a response to increasing rates of N up to 150 kg·ha−1. A critical weed-free period of 3 weeks resulted in an 844% yield increase over the nonweeded control. Overall, the results indicate that in general, tigernut requires few inputs to produce a viable commercial yield under Ontario growing conditions.

Open access

Yongjun Yue and John M. Ruter

The genus Pavonia is one of the largest genera in the Malvaceae species; it is mainly distributed in South America. Three species of Pavonia were identified based on different flower colors and potential for landscape use in the southeastern United States. These species produce a large amount of seed at the end of the blooming season, which is not ideal for ornamental use. To reduce the seed set, gamma irradiation was used for mutation induction and propensity to induce compactness and sterility. A preliminary study indicated that the seed of Pavonia hastata would germinate at irradiation rates up to 2000 Gy. Seeds of three species were treated with six different dose rates ranging from 0 Gy to 1000 Gy to determine the ideal rate for Pavonia breeding and how gamma irradiation affected seed germination. M1 (the first mutant generation) P. lasiopetala and P. missionum were sown in 2018 and planted in the field at the University of Georgia Durham Horticulture Farm on 1 May 2019, as were M2 (the second mutant generation) seeds of P. hastata. Seed germination in 2019 showed no significance due to treatment but significance due to species and species by treatment interaction. Field evaluation performed in 2019 indicated that height was not influenced by irradiation for any of the three species but that the width index was. Flower diameter and leaf area of P. missionum became smaller as the irradiation rate increased, but the other two species showed no trends. Chlorophyll mutations were observed on P. hastata at the 1500 Gy level, which has attractive traits for ornamental use.

Open access

Virginia M. Moore and William F. Tracy

Corn earworm (Helicoverpa zea) is a destructive pest with limited management options in sweet corn (Zea mays) production. Increased husk extension and the presence of the C-glycosyl flavone maysin are two proposed mechanisms for improving corn earworm resistance in corn cultivars. A factorial mating design was conducted to test hybrid combinations of sweet corn inbreds with long husks and/or maysin to identify candidates for future cultivar development. The mating design had seven male parents, including three commercial sweet corn inbreds (Wh9261, We11401, and Wt1001) and four inbreds selected for maysin content (Maysin1, 2, 3, and 4), and five female parents, including two commercial sweet corn inbreds (Ia453su and Ia5125su) and three inbreds with long, thick, tight husks (A684su, A685su, and A686su). Hybrids were evaluated for ear length, husk length, maysin content, and corn earworm resistance at six environments in 2016 and 2017. Relationships between husk extension, maysin, and corn earworm resistance were inconsistent, but five inbreds produced hybrids with significantly lower corn earworm infestation and/or damage, demonstrating potential to confer resistance to the corn earworm.

Open access

Marcela Miranda, Xiuxiu Sun, Christopher Ference, Anne Plotto, Jinhe Bai, David Wood, Odílio Benedito Garrido Assis, Marcos David Ferreira, and Elizabeth Baldwin

Coatings are generally applied to fruit as microemulsions, but nanoemulsions are still experimental. ‘Nova’ mandarins (Citrus reticulata) were coated with shellac or carnauba (Copernica cerifera) microemulsions or an experimental carnauba nanoemulsion; these were compared with an uncoated control during storage for 7 days at 20 °C. Coatings were also tested on ‘Unique’ tangors (C. reticulata × C. sinensis) stored for 14 days at 10 °C followed by a simulated marketing period of 7 days at 20 °C. Fruit quality evaluations included weight loss, gloss, soluble solids (SS), titratable acidity (TA), pH, SS/TA ratio, internal CO2, O2, fruit juice ethanol, and other aroma volatile content. Sensory visual shine and tangerine (C. reticulata) flavor rank tests after storage were conducted, followed by an off-flavor rating. The carnauba waxes resulted in less weight loss compared with the uncoated control and shellac coating during both experiments. There were no differences in gloss measurements of ‘Nova’ mandarins; however, shellac-coated fruit ranked highest for shine in a sensory test. For ‘Unique’ tangors, initially, shellac showed the highest gloss (shine) measurement; however, at the end of storage, the nanoemulsion exhibited the highest gloss, although it was not different from that of the microemulsion. Similarly, after storage, the nanoemulsion ranked highest for visual shine, although it was not different from that of the microemulsion. There were only minor differences in SS, TA, pH, and SS/TA among treatments. The internal CO2 gas concentration and juice ethanol content generally increased and internal O2 decreased during storage. The highest levels of CO2 and ethanol were found for the shellac treatment, as was the lowest O2, indicating anaerobic respiration. There were only minor differences among the other coating treatments; however, they were only sometimes different from those of the control, which generally had the highest O2, lowest CO2, and lowest ethanol. Shellac and the carnauba microemulsion also altered the volatile profile more than the control and the nanoemulsion did, especially for ‘Unique’ tangors. For ‘Unique’ tangors, the control and nanoemulsion ranked highest for tangerine flavor and had the least off-flavor at the end of storage. Among the coatings tested, the carnauba emulsions demonstrated less water loss, imparted more sustainable gloss, and caused less ethanol production than shellac, with the nanoemulsion exhibiting higher gloss measurements, less modifications of the atmosphere and volatile profile, and, consequently, better flavor compared with the microemulsion.

Open access

Rachel P. Naegele and Mary K. Hausbeck

Phytophthora capsici causes root and fruit rot and foliar blight of pepper. Multiple sources of resistance to Phytophthora root rot have previously been identified, but most display only partial resistance. One source, CM334, has broad spectrum root rot resistance to multiple pathogen isolates but has only low to moderate fruit rot resistance. This study evaluated previously identified pepper lines for resistance to two P. capsici isolates, OP97 and 12889, and compared root rot resistance to fruit rot resistance and genetic structure. CM334 was confirmed as a broad spectrum resistance genotype, whereas all other sources of resistance evaluated were susceptible to infection by one or both isolates evaluated. Although not completely resistant, PI 566811 displayed moderate resistance to fruit and root rot to both P. capsici isolates. Fruit rot resistance had a significant but small to moderate positive correlation (r = 0.26–0.63) with root rot resistance depending on the isolate and length of exposure. Pepper accessions with resistance to Phytophthora root and fruit rot belonging to different genetic subpopulations were identified and could serve as candidates for partial-resistance loci to incorporate into pepper breeding programs.