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Open access

Travis Wayne Shaddox and Joseph Bryan Unruh

Numerous nitrogen (N) sources are used in turfgrass management and vary from soluble to slow-release. Determining the least expensive N source can be confusing for consumers. Price per ton and price per pound N are common price comparison methods. An improved approach could use longevity of the N source to balance the price. The objective of this study was to determine the longevity of turfgrass response to N sources and to determine the cost to achieve such responses. This study was conducted in Ft. Lauderdale and Jay, FL, from 1 Jan. to 31 Dec. 2018 on ‘Riley’s Super Sport’ (Celebration®) bermudagrass (Cynodon dactylon). Treatments included nontreated turfgrass, urea, ammonium sulfate, stabilized urea, methylene urea, ureaformaldehyde, two natural organics, sulfur-coated urea, and two polymer-coated urea fertilizers. Treatments were arranged in a split-plot design with N sources as whole plots and N rate (N applied at 49 and 98 kg·ha−1 every 4 months) as subplots. Turf quality was recorded on a scale of 1 to 9, where 1 = dead/brown turf and quality, 6 = minimal acceptable, and 9 = optimal healthy/green turf. Turf quality ratings were recorded weekly and used to determine response longevity (days quality ≥6.0) and area under the turfgrass response curve (AUTRC). Urea resulted in response longevity greater than or equal to other N sources during each season except when applied at 98 kg·ha−1 of N during the fall fertilizer cycle in Jay. Natural organics were ≈6-fold more expensive than urea in Jay and Ft. Lauderdale using turfgrass response longevity and AUTRC. Urea and sulfur-coated urea were the least expensive soluble and slow-release N source, respectively, using dollars per pound N, dollars per acre per day, and dollars per acre per quality-day during each fertilizer cycle and annual average in Jay and Ft. Lauderdale. No evidence was found supporting the use of turfgrass response as a more effective method of determining fertilizer cost than dollars per pound N.

Open access

Asma Mohammed Saeed Al-Kubati, Baoshan Kang, Liming Liu, Aqleem Abbas, and Qinsheng Gu

Zucchini yellow mosaic virus (ZYMV) causes serious damage to cucurbit crops worldwide and can be spread by aphids, by mechanical injury, and in seeds. With the popularization of cucurbit grafting, the use of susceptible rootstock has increased the risk of ZYMV infection in cucurbit crops. In China, the bottle gourd (Lagenaria siceraria) is a widely used rootstock in grafted watermelon production. However, few resistant bottle gourds are available commercially. This study developed bottle gourd lines resistant to ZYMV using ethyl methanesulfonate (EMS) mutagenesis. A new mutated bottle gourd population (M1) was generated by treating seeds with EMS. Diverse phenotypes were observed in the seedlings, flowers, and fruit of M2 plants, some of which are of potential commercial interest, such as dwarfing and different fruit shapes. Based on the M2 phenotypes, 106 M3 lines were selected and screened for resistance to ZYMV by mechanical inoculation and agroinfiltration. Nine M3 lines were resistant to ZYMV during three tests. One inbred M4 line (177-8) was developed and showed stable resistance and no virus when tested using a double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and polymerase chain reaction. These resistant lines are promising materials for developing watermelon rootstock and exploring resistance genes as new ZYMV-resistant resources. EMS induction could be a practical strategy for creating resistant cucurbit crops.

Open access

Juming Zhang, Michael Richardson, Douglas Karcher, John McCalla, Jingwen Mai, and Hanfu Luo

Many bermudagrass (Cynodon sp.) and zoysiagrass (Zoysia sp.) cultivars are not available as seed and are commonly planted vegetatively using sprigs, especially for sod production or in sand-based systems. Sprig planting is typically done in late spring or early summer, but this can result in an extended grow-in period and delay the use of the turf in the first growing season. The objective of this study was to determine if sprigs of bermudagrass and zoysiagrass could be planted earlier in the year, during the dormancy phase, to hasten establishment. A field study was carried out in Fayetteville, AR, in 2014 and 2016 using ‘Tifway’ hybrid bermudagrass (Cynodon dactylon × Cynodon transvaalensis) and ‘Meyer’ zoysiagrass (Zoysia japonica), and in Guangzhou, China, in 2015, using ‘Tifway’ hybrid bermudagrass and ‘Lanyin III’ zoysiagrass (Z. japonica). Sprigs were planted in March (dormant), May (spring) and July (summer) in Fayetteville, and in January (dormant), March (spring) and May (summer) in Guangzhou. Sprigging rates of 30, 60, and 90 m3·ha−1 were tested at both locations and across all planting dates. Bermudagrass was less affected by planting date, with dormant, spring or summer plantings effectively establishing full cover in the first growing season. Zoysiagrass that was sprigged in the dormant season was successfully established by the end of the first growing season while a full zoysiagrass cover was not achieved with either spring or summer plantings in Arkansas. Dormant sprigging reached full coverage as fast or faster than traditional spring or summer planting dates at both locations, indicating that bermudagrass and zoysiagrass establishment can be achieved earlier in the growing season using dormant sprigging methods.

Open access

Ariel Singerman, Stephen H. Futch, and Brandon Page

Citrus greening or Huanglongbing (HLB) has caused sweet orange (Citrus sinensis) yield in Florida to decrease by 55% since the disease was first discovered in 2005. As a consequence, the profitability and sustainability of citrus (Citrus sp.) production in Florida have been jeopardized, as evidenced by the 62% reduction in the number of citrus growers statewide. Because there is still no effective treatment or management strategy to cure the disease, it is crucial to optimize grove practices and management. The use of improved rootstocks could increase the tolerance of citrus scions to biotic and abiotic stresses, thereby allowing growers to cope better with the impact of HLB in the field. We used yield data collected from commercial trials over the course of multiple seasons to assess the side-by-side performance of various commercially available rootstocks developed by the two major breeding programs in Florida in HLB-endemic field conditions. We found that some of the rootstocks attained not only statistically significant differences in yield relative to the control but also meaningful differences in revenue. Those estimates provide evidence regarding the effect of rootstock during the first few seasons after planting. Our findings are useful to improve growers’ decision-making processes regarding rootstock selection for new groves.

Open access

Mitchell E. Armour, Margaret Worthington, John R. Clark, Renee T. Threlfall, and Luke Howard

Red drupelet reversion (RDR) is a postharvest disorder of blackberries (Rubus L. subgenus Rubus Watson) in which fully black drupelets revert to red after harvest. This disorder can negatively impact consumer perception of fresh-market blackberries. The cause of RDR is hypothesized to be related to intracellular damage sustained because of mechanical and environmental stress during and after harvest. Cultivars differ in susceptibility to this disorder; and cultural factors, including nitrogen rate, harvest and shipping practices, and climate during harvest, influence RDR severity. In this 2-year study, seven genotypes (cultivars and advanced selections) developed in the University of Arkansas System Division of Agriculture (UA) blackberry breeding program, with a range of fruit textures, were evaluated to determine whether firmness was correlated with RDR. In addition, fruit was harvested at four different times (7:00 am, 10:00 am, 1:00 pm, and 4:00 pm) to investigate whether harvest time influences RDR. All seven genotypes were harvested at the four times on two harvest dates per year and evaluated for RDR and firmness after 1 week of cold storage (5 °C). Fruit harvested early in the day had less RDR, with 7:00 am harvests having the least RDR in both years. Significant genotypic differences in RDR and fruit firmness were found in each year. Firmness was negatively correlated with RDR in 2018 and 2019. These results indicate that growers may be able to reduce the prevalence of RDR by choosing cultivars with firm fruit texture and harvesting early in the day.

Open access

Jia Tian, Yue Wen, Feng Zhang, Jingyi Sai, Yan Zhang, and Wensheng Li

Large-fruit bud mutations are important factors in fruit tree breeding. However, little is known about the differences between varieties and bud mutations. The ploidy identification of Korla fragrant pear (Pyrus sinkiangensis Yu) and its large bud mutation Zaomeixiang pear showed that the large-fruit characteristic was not caused by chromosome doubling. By counting mesocarp cells at different stages, we found that the number of cells increased continuously after pollination, and the difference was the greatest at 28 days after full bloom (DAFB), and was about 9.4 × 106. After 28 days, the difference in cell volume became bigger and bigger, so both the cell volume and cell number caused the difference in fruit size between Korla fragrant pear and Zaomeixiang pear. To obtain more insights into the differences in fruit size driven by cell division, we analyzed the endogenous hormones [indole ascetic acid (IAA), zeatin riboside (ZR), gibberellic acid (GA), and abscisic acid (ABA)], and the main sugars (glucose, fructose, sucrose, and sorbitol). The ZR content of Zaomeixiang pear was always greater than that of Korla fragrant pear at all stages. The ABA content was the opposite except for at 7 DAFB during cell division; the greatest difference was 30.87 ng/g, which appeared at 28 DAFB. ABA and ZR correlated negatively with cell number. After 7 DAFB, the ratio of IAA/ABA, ZR/ABA, and GA/ABA in Zaomeixiang pear was always greater than that for Korla fragrant pear at 28 DAFB. The difference in glucose content at 21 DAFB was the greatest, at 4.80 ng/g. Large amounts of sorbitol accumulated during whole-cell division. Glucose and sorbitol correlated positively with cell numbers. In summary, the data suggest that the different contents of glucose, sorbitol, ZR, and ABA, and the ratio of endogenous hormones might be related to cell division in Korla fragrant pear and Zaomeixiang pear. The result provides a theoretical basis for the large-size fruit’s high-quality production and genetic breeding of Korla fragrant pear and its bud mutation.

Open access

Hardeep Singh, Bruce Dunn, Niels Maness, Lynn Brandenberger, Lynda Carrier, and Bizhen Hu

Tomato (Solanum lycopersicum L.) is one of the most extensively cultivated horticultural crops in the world. Factors such as yield, size, taste, and lycopene content are important criteria that may impact the selection of tomato cultivars for different production systems. The aim of the current study was to evaluate different slicer and cherry tomato cultivars for production under greenhouse and open field conditions. Three cultivars of slicer (BHN 964, Trust, and Geronimo) and cherry (BHN 268, Favorita, and Sakura) tomatoes were tested using randomized complete block design in 2019 and 2020. Results showed that the performance of tested cultivars differed under greenhouse verses open field conditions. Among cherry tomato cultivars in 2020, BHN 268 and Sakura produced significantly greater yield under open field conditions, while under greenhouse conditions yield of BHN 268 was the lowest. Similarly, cherry tomato fruit size from ‘BHN 268’ and ‘Sakura’ was also significantly greater than ‘Favorita’ under field conditions, whereas under greenhouse conditions, the fruit size of ‘Sakura’ was significantly greater than both ‘BHN 268’ and ‘Favorita’. Among slicer tomato cultivars, BHN 964 produced significantly greater yield and had a greater average fruit size than the other two cultivars under greenhouse conditions in 2020 while, Geronimo produced significantly similar or larger yield and had a similar average fruit size compared with BHN 964 under open field conditions. Tomatoes produced under open field conditions were rated significantly greater for taste compared with those produced under greenhouse conditions. Lycopene content in both slicer and cherry tomato cultivars was influenced by the interaction of production type, cultivars, and harvest time. Therefore, it can be concluded that BHN 964 and Geronimo were the highest in lycopene among slicer tomato cultivars for greenhouse and open field production, respectively. Among cherry tomato cultivars, BHN 268 was the highest in lycopene for open field production and Sakura for greenhouse production. Additionally, open field–produced tomatoes taste better than greenhouse-produced tomatoes, but lycopene content may be constrained for mid- and late-season fruits due to high temperature conditions under open field conditions.

Open access

Joseph Thomas and Matthew Taylor

Fountain grass (Pennisetum alopecuroides) is a common ornamental grass because of its glossy foliage and showy inflorescence. However, there have been reports of populations growing outside of cultivation and demonstrating invasive tendencies. There is limited research of the chemical control of fountain grass in natural areas. The objective of this experiment was to evaluate the impact of glyphosate, sethoxydim, and fluazifop on fountain grass. Treatments consisted of 2250 and 4500 g⋅ha–1 glyphosate, 262.5 and 525 g⋅ha–1 sethoxydim, and 200 and 400 g⋅ha–1 fluazifop; a nontreated control group was also included. The percent herbicide injury was determined visually 1, 3, 4, 6, and 10 weeks after treatment (WAT). Both rates of glyphosate resulted in 100% of the foliage injured by 3 WAT. The application of flauzifop and sethoxydim led to intermediate results ranging from 15% to 23% injury by 6 WAT, with no significant difference between active ingredients or rates. Nontreated control plants exhibited little to no injury throughout the study. Flauzifop, sethoxydim, and glyphosate all caused visible injury to fountain grass. For complete, fast-acting control, glyphosate is recommended. Herbicide control coupled with restorative plantings of native plants can help reduce invasive plant pressure and improve biodiversity of natural areas.

Open access

Noah J. Langenfeld and Bruce Bugbee

Dissolved oxygen (DO) is critical for aerobic life in aquatic environments. Rapid and accurate measurements of DO are necessary to quantify the rate of oxygen uptake and maintain optimum conditions in root zones. DO meters are available across a price range of USD99 to more than USD1000. We compared three meters for stability, response time, and accuracy in freshwater [tap water, 0 g⋅L–1 sodium chloride (NaCl)] and saline water (simulated seawater, 35 g⋅L–1 NaCl) across multiple temperatures. The Yellow Springs, Inc. 550A (YSI) and Sper Scientific 850048 (Sper) meters were stable across a range of water temperatures (12–38 °C) and salinity. The Smart Sensor Roeam AR8210 drifted ±50% within minutes after calibration and was not evaluated further. In freshwater, the YSI meter was within 4% and the Sper meter was within 5% of the theoretical value at 12 and 22 °C. Meters were less accurate at 38 °C. The accuracy in saline water was similar to freshwater. Across temperature and salinity, the response time averaged 10 s for the YSI meter and 15 s for the Sper meter. We conclude that the YSI and Sper meters can provide rapid, stable, and accurate measurements of DO.

Open access

Aaron G. Anderson, Isabella Messer, and Gail A. Langellotto

Plantings of native flowers are often installed to increase the pollinator habitat in urban and suburban gardens. However, in many regions, it is not known which native plants are best used for pollinator plantings in gardens. Candidate plants must be attractive to pollinators, but they also must have attributes that gardeners find appealing. To identify native plants that are attractive to gardeners, we disseminated two surveys. The first asked gardeners to use a 5-point Likert scale to rate how likely they would be to garden with 23 flowering plants native to the Pacific Northwest United States. The second survey asked gardeners to use a 5-point Likert scale to rate how likely they would be to garden with a subset of 11 of these 23 native plants before and after receiving information about each flower’s attractiveness to bees (Anthophila). Using the first survey, we found a high level of acceptance of native plants by home gardeners (6 of 23 flowers had a mean “likelihood of planting” score of ≥ 4). Additionally, gardeners stated their likelihood of planting these native species increased significantly after receiving information about the bees associated with each plant. Across both surveys, gardeners who identified as “native plant gardeners” stated they would be significantly more likely to garden with all native plant species. Both surveys included an opportunity to share open-ended comments, which revealed that gardeners were most concerned with flower aesthetics and the aggressiveness of growth. Gardeners felt most positively about flower aesthetics and beneficial ecological traits. Many gardeners also commented that they needed more information or were unfamiliar with the plants. This study shows that native plants can have high baseline appeal to home gardeners. Specifically, we identified five native plant species that northwestern U.S. nurseries might consider growing and marketing as pollinator plants because of their high level of attractiveness to bees and home gardeners: globe gilia (Gilia capitata), california poppy (Eschscholzia californica), douglas aster (Symphyotrichum subspicatum), oregon sunshine (Eriophyllum lanatum), and common yarrow (Achillea millefolium).