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Open access

Rahmatallah Gheshm and Rebecca Nelson Brown

Saffron is well known as the most expensive spice in the world by weight. It is the dried stigmas of the saffron crocus (Crocus sativus). Besides being well known as a culinary spice, saffron is also important in the pharmaceutical, cosmetic, and dye industries. Saffron crocus is cultivated in a wide range of environments, from the Mediterranean to the Middle East, and even to northern India’s subtropical climate. Saffron crocus is an environmentally friendly and low-input crop, making it a perfect match for low-input and organic farming, and sustainable agricultural systems. The objective of this study was to evaluate the possibility of producing saffron in New England. The study was conducted from Sept. 2017 to Dec. 2019 at the University of Rhode Island. Two different corm planting densities and two winter protection methods were evaluated. In 2018, corm planting density did not affect the number of flowers per unit area or total stigma yields, but flowers from the low-density plots produced significantly (P < 0.05) heavier pistils than flowers from the high-density plots. In 2019, planting density had no effect on flower number, stigma yield, or pistil dry weight. In 2018, flower number, stigma yield, and pistil dry weight were similar to subplots that had been covered with low tunnels the previous winter and subplots that had not been covered. However, in 2019, the plants in the subplots that remained exposed during the winter produced significantly more (P < 0.05) flowers than the plants in the subplots that were in low tunnels for the winter. Saffron yields followed the same pattern, with the unprotected subplots yielding 57% more than the protected subplots (P < 0.05). These data indicate that winter protection is not beneficial for saffron crocus production in Rhode Island. The use of winter protection increases production costs and can decrease yields.

Open access

Ravi Bika and Fulya Baysal-Gurel

The cut flower growers of the eastern and southern United States are threatened with postharvest meltdown of zinnia (Zinnia elegans), which reduces yield and income as well as limiting opportunities for production expansion. Disease symptoms such as bending of the stem just below the flower were visually apparent on zinnia cut flowers. The objective of this study was to identify the causal agent related to zinnia meltdown. A total of 20 symptomatic zinnia cut flower stems were collected from Tennessee. Several Fusarium-like colonies with micro and macroconidia were isolated from the base and bend area of stems on potato dextrose agar (PDA) and Fusarium-selective media. Morphological characterization, polymerase chain reaction, and sequencing of three representative isolates, FBG2020_198, FBG2020_199, and FBG2020_201, were conducted to confirm pathogen identification. The sequence identity of the isolates was >99% identical to Fusarium commune, and a combined phylogenetic tree grouped the isolates with the clade of F. commune from different host and geographical locations. To accomplish Koch’s postulates, a pathogenicity test was performed on ‘Benary’s Giant Golden Yellow’, ‘Benary’s Giant Lime’, and ‘Benary’s Giant Pink’ zinnia plants at vegetative (2 weeks after transplantation) or flower bud stage (1 month after transplantation) by drench, stem injection, and foliar spray of conidial suspension (1 × 105 conidia/mL). Similar symptoms of meltdown (floral axis bending just below the flower) were observed on inoculated zinnia cultivars 2 days after harvesting. Fusarium commune was re-isolated from the infected flower stems of all three cultivars but not from the noninoculated zinnia flower stems. Zinnia stem colonization by F. commune was statistically similar in all three tested cultivars regardless of plant growth stage and method of inoculation. This study confirms F. commune as being the causal agent of postharvest zinnia flower meltdown issue in Tennessee. In the future, possible sources of pathogen will be screened, and disease management recommendations will be developed.

Open access

Seon-Ok Kim, Su-Been Pyun, and Sin-Ae Park

The aim of this study was to compare the physiological and psychological effects in the elderly during horticultural and nonhorticultural activities as leisure activities. A total of 58 participants aged 65 or older (29 men and 29 women; average age, 74.0 ± 4.7) whose cognitive function was within the normal range were included in this study. Participants performed four horticultural and four nonhorticultural activities for 2 min, respectively. The study had a cross-over experimental design. Electroencephalography was performed during all the activities. Subjective evaluation of emotions was performed using the Profile of Mood States immediately after each activity. The collected statistical data were analyzed using Duncan’s test as a post-analysis of variance test to verify the differences in the results of electroencephalography and the Profile of Mood States according to the different activities. In the results of the electroencephalography, the relative beta, gamma, low-beta, and ratio of sensorimotor rhythm to theta indices indicate that the degree of brain activity in the prefrontal lobe was high during activities such as washing leaves, transplanting plants, and reading news. The results of the Profile of Mood States showed that during activities such as arranging flowers, transplanting, and washing leaves, the total mood disorder score was lowered, indicating a positive effect on the mood of the participants. This study shows that activities such as washing leaves, transplanting, and reading news have a positive effect on the cognitive function of elderly people by increasing brain activity.

Open access

Nianwei Qiu, Li Tian, Xifeng Yan, Haoyu Dong, Mengyu Zhang, Guoliang Han, and Feng Zhou

The structure and chemical properties of strontium and calcium are similar. To study the interplay between calcium and strontium in plants, different concentrations of SrCl2 (0, 1, 4, and 10 mmol·L−1) were added to the Hoagland nutrient solution with 4 mmol·L−1 Ca2+ (normal level Ca2+) or 0.4 mmol·L−1 Ca2+ (low-level Ca2+), which were used to cultivate Chinese cabbage seedlings. Under the low-level calcium condition, strontium not only did not promote the growth of Chinese cabbage but showed more severe toxicity compared with that under the normal calcium condition. Under normal calcium condition, although the growth of Chinese cabbage was significantly inhibited by 4 mmol·L−1 strontium, strontium did not show significant toxicity. However, under the low-level calcium condition, 1 mmol·L−1 strontium caused a significant decline of plant biomass and photosynthetic activity. Sr2+ showed a competitive inhibitory effect on the absorption of Ca2+, and strontium was more easily absorbed by Chinese cabbage. Under the low-level calcium condition, strontium aggravated the inhibition of calcium absorption. The inhibitory effect of strontium on plant growth was significantly related to the calcium content in Chinese cabbage. Strontium cannot replace the function of calcium in plants under calcium-deficient conditions.

Open access

S. Christopher Marble and Stephen H. Brown

Plant invasions pose a serious threat to biodiversity, agricultural production, and land value throughout the world. Due to Florida’s unique climate, population expansion, expansive coastline, and number of seaports, the state is especially vulnerable to non-native plant naturalization and spread. Invasive plant management programs were shown to have higher success rates with fewer resources when invasives were managed soon after non-native plants were observed. However, some newly emerging invasive plants may go undetected due to their resemblance with native species or other invasive plants. The objective of this review is to highlight a few key invasive plants in Florida that have native lookalikes. While morphological differences are discussed, the primary goal is to discuss management implications of misidentification and delayed response times, as well as the need for plant identification guides that include information on how to distinguish problematic invasive plants from similar native species.

Open access

Amanda J. Davis and Bernadine C. Strik

In long-lived organic blueberry production systems, nutrient imbalances caused by some fertilization and mulching practices can reduce plant growth and yield. The ability to balance nutrient levels and thus improve productivity over time was evaluated in a mature planting of ‘Duke’ and ‘Liberty’ that had been used to study different mulching practices [sawdust (9-cm deep), yard-debris compost (4-cm) topped with sawdust (5-cm), and weed mat] and various rates and sources of N fertilizer (feather meal or fish solubles, each applied initially at “low” or “high” rates of 29 and 57 kg·ha−1 N in 2007–08 and then increased incrementally as the planting matured to 73 and 140 kg·ha−1 N in 2013–16). In Winter 2016–17, existing weed mat was removed and replaced where it was present, and new weed mat was installed on top of any existing organic mulches, thus changing the mulch treatments to weed mat (over bare soil), weed mat over sawdust, and weed mat over compost + sawdust from 2017 to 2020. A hydrolyzed soy-protein–based fertilizer containing essentially only N was applied at a moderate rate (106 kg·ha−1 N) relative to prior treatments. Plants grown on flat and raised beds were evaluated separately. From 2016 to 2020, yield of ‘Duke’ and ‘Liberty’ increased by an average of 19% and 56%, respectively, on flat beds and 8% and 42%, respectively, on raised beds. On flat or raised beds, plants that had weed mat placed over the existing sawdust or compost + sawdust mulch had a greater increase in yield (averaging 41%) than those with weed mat alone (over bare soil; averaging 12%). Soil under weed mat alone continued to have the lowest organic matter content (averaging 3%) throughout the study. Prior fertilization source and rate had no impact on the increase in yield of ‘Duke’, whereas ‘Liberty’ plants previously fertilized with feather meal had a larger increase in yield through 2020 than those fertilized with fish solubles. Fertilizing with an intermediate rate of N from 2017 to 2020 increased yield regardless of whether plants received the low or high N rate from 2007 to 2016, confirming our previous conclusion that the low rate provided sufficient N. Soil K and leaf %K declined after discontinuing fertilization with fish solubles and use of yard-debris compost, likely a factor in yield improvement. However, there were still negative correlations between yield and leaf %K in multiple years. This study illustrated that changing mulch and fertility practices in established organic blueberry to mitigate prior applications of high K can improve plant performance, nutrient imbalances, and yield within a relatively short period of time.

Open access

Neil O. Anderson, Alan G. Smith, Andrzej K. Noyszewski, Emi Ito, Diana Dalbotten, and Holly Pellerin

The issue of native invasive species management rarely occurs and is fraught with biological, social, and economic challenges as well as posing difficulties in decision-making for land managers. The terminology for categorization of invasive species is examined in the context of their bias(es), which complicates control. An example of a newly determined native species, which is also invasive, is used as an example to navigate control and regulatory issues. Native, invasive reed canarygrass (Phalaris arundinacea L.) occurs throughout Minnesota and most likely the entire midwest region of central United States and Canadian provinces. The species was previously assumed to be an exotic, nonnative Eurasian import but recent molecular evidence supports its status as a native but invasive species. We address how this change to being a native but highly invasive species modifies approaches to mitigate its potential control for state, Tribal, and local authorities. The implications of these new findings will require differential shifts in land managers’ perspectives and approaches for control. Particular differences may exist for Tribal Land Managers vs. departments of natural resources and private agencies. Additionally, regulatory challenges have yet to be decided on how to legislate control for a native invasive species that had been previously assumed as exotic or foreign in origin. These opportunities to change attitudes and implement judicial control measures will serve as a template for other invasive species that are native in origin.

Open access

Irfan Ali Sabir, Xunju Liu, Songtao Jiu, Matthew Whiting, and Caixi Zhang

Sweet cherry (Prunus avium L.) is a valuable fruit crop worldwide. Farmers’ incomes are closely related to fruit quantity and quality, yet these can be highly variable across years. As part of a broader project for optimizing fruit set and fruit quality in sweet cherries, this study was conducted to evaluate the potential of various plant growth regulators (PGRs) for improving fruit set and fruit quality. Cytokinins, gibberellins, auxin, and polyamines were used as treatments. Treatments were applied as foliar sprays at full bloom to ‘Bing’ and three low-productivity genotypes, ‘Regina’, ‘Tieton’, and ‘PC8011-3’. We assessed the fruit set, fruit quality, and return bloom from each treatment. 4-chlorophenoxyacetic acid (4-CPA) increased fruit set by 53% and 36% in ‘Bing’ and ‘Tieton’, respectively. The combination of gibberellin (GA)3 + GA4/7 was more effective for improving fruit set than other isomers of gibberellin alone. Cytokinin treatments had slight adverse effects or no effect on fruit set except for CPPU. In ‘PC8011-3’, both N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU) and 4-CPA enhanced fruit set by ≈81% and 100% compared with untreated control. The response of cherry trees to polyamine sprays depended on the properties of the cultivars and the treatment concentration. Foliar application of GA3, GA4/7, or N-phenyl-N'-(1, 2, 3-thiadiazol-5-yl) urea (TDZ) in ‘Bing’ trees has negative effects on return bloom, whereas GA1 can increase the yield and flower buds. These results suggest that PGRs may have varied effects on sweet cherry fruit set and that more work is needed to develop practical programs for improving yield security.