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Fruit size and sugar content are key determinants of fruit quality, influenced by environmental factors and agronomic practices and sink strength provided by the genetic potential. Strawberry (Fragaria ×ananassa) produces fruits arranged in inflorescences, whose growth is affected by carbon competition between them. The competitive ability is termed as sink strength, which can be quantified as the potential growth rate under sufficient resource supply and/or no carbon competition among sinks, referred to as non-limiting conditions. Most previous studies did not observe potential growth, thereby failing to adequately evaluate sink strength and to assess the influence of environmental factors and agronomic practices on fruit growth. This study aimed to investigate the potential growth of strawberry fruits and analyze its sink strength dynamics. Non-limiting conditions were established by removing flowers to one fruit per inflorescence in a greenhouse experiment with plants grown in soil and given water and nutrients through drip irrigation. Fruits were harvested every 5 days from 5 to 55 days after anthesis (DAA), measuring the size, weight, and concentrations of major soluble carbohydrates in strawberry (sucrose, glucose, and fructose) and starch. Sink strength was represented by absolute growth rate based on fruit weight, and its components, sink size and sink activity, were represented by weight and relative growth rate, respectively. Fruit volume and weight showed a gradual linear increase at 5 DAA and then rapidly increased, following a single sigmoid curve between 30 and 55 DAA. Fruits primarily accumulated glucose and fructose during early growth, shifting to sucrose after 35 DAA. Starch concentration peaked at 5 DAA and then exponentially decreased. Sink strength exhibited a single peak between 40 DAA and 45 DAA. Sink strength gradually increased with sink size until 30 DAA, whereas sink activity significantly decreased until 30 DAA. Thereafter, sink strength and sink activity exhibited a peak, whereas sink size continued to increase. These results suggest that the major determinant of sink strength was sink size during early fruit growth, shifting to sink activity during late growth.
Interest in local foods, especially locally grown fruit, is increasing. High tunnel vegetable growers are strategically poised to meet this demand by growing specialty melons (Cucumis melo). Although specialty melons are commonly grown in high tunnels in other parts of the world, it is an uncommon practice in the midwestern United States. The objectives of this study were to evaluate 10 specialty melon cultivars for high tunnel production and measure fruit yield and internal quality. Fruit of the cultivar Eden’s Gem yielded the greatest number of marketable fruits per plant; however, these melons are small and have a loose cavity. Fruit of the cultivars Honey Orange and Divergent yielded the largest marketable fruit per plant with tighter cavities; however, the cavities were large. All cultivars had good to excellent internal quality in terms of sugar content. The production of specialty melons in the high tunnel was successful, resulting in the production of melons with good to excellent internal quality, and several yielded three to four marketable fruit per plant. Implementing a strong pest management plan for cucumber beetle (Diabrotica undecimpunctata howardi) and powdery mildew (Erysiphe cichoracearum, Sphaerotheca fuliginea) is recommended to prevent yield loss, especially in locations such as the Midwest, where cucumber beetles often vector bacterial wilt (Erwinia tracheiphila).
This review was conducted to synthesize current knowledge, learn producer and Extension specialist perspectives, and identify gaps in understanding of the role of soil health in sustaining production in high tunnel (HT) systems. This synthesis includes findings from scholarly resources related to soil health in HTs, including research and Extension-based literature, perspectives from experienced HT producers and technical assistance providers, and the direct observations of a broad network of university research and Extension personnel working with HTs. Findings are intended to identify knowledge gaps and additional research and Extension resource needs of greatest priority to the HT producer community and technical assistance providers that support them at the time of publication. A review of 68 research articles and 58 Extension resources was conducted. Focus group interviews were conducted with small groups of experienced HT farmers in four regions of the eastern half of the United States, with in-depth farm case studies conducted in individual farmers in three of these regions. Growers across regions identified soil fertility management, soilborne diseases, soil compaction, and lack of consistency of soil analyses specific to HTs as the greatest soil-related challenges to HT production. Research and resources for technical assistance providers on mitigation strategies to remediate yield-limiting HT soil conditions, such as excessive soil salinity and high pathogen populations, were also lacking. As such, process-based research on techniques such as leaching, soil steaming, solarization, and anaerobic soil disinfestation in tunnels that consider short- and long-term costs, benefits, and effects on soil and plant productivity should be prioritized in the future when considering the impact of HT production on soil health. Interviews also indicated a need for networking opportunities for technical assistance providers across agencies (e.g., Natural Resources Conservation Service, Extension, nongovernmental organizations). Despite a high and increasing rate of adoption, there is currently a lack of information about maintaining HT systems. Given that HTs play a critical and growing economic role for specialty crop growers throughout the eastern United States, comprehensive intervention across the research–Extension spectrum to sustain productivity in HT systems is recommended.
Cover crops have a long and significant history in Florida’s citrus industry. During the late 1800s and early 1900s, they were widely used to enhance soil quality, boost fertility, and manage pests; therefore, they served as a critical agricultural tool before the widespread adoption of synthetic fertilizers. However, during the middle of the 20th century, a decline in the use of cover crops occurred as synthetic fertilizers and chemical pest control methods became more prevalent. Despite this decline, a resurgence of interest in cover crops has occurred among Florida’s citrus growers. This renewed interest is driven by the urgent need to increase soil fertility while reducing inputs, particularly in the context of managing citrus groves affected by citrus greening [huanglongbing (HLB)], which is a devastating disease that threatens the viability of the citrus industry. Citrus greening has created a growing interest in the use of management practices that can help mitigate the increasing cost of inputs needed to manage the disease. This literature review delves into the historical use of cover crops in Florida’s citrus industry and highlights their early adoption and subsequent decline. Additionally, it examines current cover crop management practices and focuses on key components such as seed selection, planting techniques, and termination methods. Finally, this review discusses the challenges and limitations associated with integrating cover crops into modern citrus production systems.
Local variety trial data are necessary for informing growers how a specific variety might perform on their farm but there is a growing deficiency in these data, particularly for specialty crops. To address this issue, an online decision-support tool named the Vegetable Variety Navigator (VVN) was developed in 2020 to compile, analyze, and visually communicate publicly available broccoli (Brassica oleracea var. italica), cucumber (Cucumis sativus), and sweet pepper (Capsicum annuum) variety trial data. To validate the accuracy and predictive potential of the VVN, we conducted 16 on-farm variety trials for broccoli, cucumber, and sweet pepper between 2020 and 2022. Yield of each variety in a trial was compared with the mean of all other varieties in the same trial to calculate a mean relative yield (MRY). The difference between observed relative yield in the field and predicted relative yield from the VVN (ΔMRY) was used to assess the accuracy of three different VVN prediction strategies. Strategies included using data from the following: 1) the single geographically nearest trial, 2) the mean of the three geographically nearest trials, or 3) the mean of all available trial data regardless of location. Compared with random predictions of MRY for each variety (from within a normal distribution of MRY values in the VVN database), the VVN predictions reduced ΔMRY and improved the accuracy of relative yield predictions across varieties by up to 21% in broccoli, 51% in cucumber (depending on strategy), and 51% in sweet pepper. Results confirm the value of the VVN as a decision-support tool for growers facing an ever-increasing number of crop variety options with less variety trial data. Future research and development are needed to improve the accuracy of the VVN by accounting for possible effects of crop types, management, and location on relative yield and quality.
This study aimed to investigate the psychophysiological effects of horticultural activities on the prefrontal cortex (PFC) to understand how horticultural activities can influence mental health and cognitive function. This study involved 39 adults with an average age of 54.6 years (±12.5 years) and was conducted in a laboratory setting at Konkuk University. The impact of five different types of horticultural activities—sowing, transplanting, planting, harvesting, and packaging—on PFC oxyhemoglobin (oxy-HB) concentrations was assessed. Functional near-infrared spectroscopy (fNIRS) was used to measure oxy-HB levels in the PFC while participants engaged in each activity for 90 seconds. The results indicated that the overall PFC oxy-HB concentration was at its lowest during planting and at its highest during sowing (P < 0.001). In the right PFC, oxy-HB was also at its lowest during planting and at its highest during sowing (P < 0.01). In the left PFC, the lowest oxy-HB concentrations were observed during both planting and harvesting, whereas the highest oxy-HB concentrations were observed during transplanting and sowing (P < 0.001). Additionally, sex-based differences were noted, with females showing significantly lower oxy-HB concentrations during sowing (P < 0.05) and transplanting (P < 0.01) than those of males. These findings suggested that psychophysiological responses, as indicated by oxy-HB concentrations, vary depending on the type of horticultural activity and by sex.
Visual stimuli from green plants have positive effects on mental health. This study aimed to compare human responses to varying plant types [live, artificial, two-dimensional (2D), and three-dimensional (3D) plant models] as visual stimuli. Thirty adults (age, 29.9 ± 11.5 years) viewed each plant form while an electroencephalography (EEG) measured their brain activity. Psychological responses were assessed using the semantic differential method (SDM). No significant differences were observed among visual stimuli; however, brain activity differences varied between male and female participants. Males who observed live and artificial plants had a higher relative alpha (RA) spectrum (RAS) and relative fast alpha (RFA) spectrum frequencies at Fp1 and Fp2 (P < 0.05 and P < 0.01 vs. P < 0.05 and P < 0.01, respectively), indicating greater emotional stability. Similarly, male participants who viewed 2D models had higher RA and RFA frequencies at Fp1 (P < 0.01, P < 0.01) and Fp2 (P < 0.05, P < 0.01). Male participants who observed 3D models exhibited higher RA, RSA, and RFA frequencies at Fp1 (P < 0.01). Live and artificial plants were deemed the most calming (P < 0.01). Both sexes found live plants to be the most pleasant (males: P < 0.01; females: P < 0.05) and natural (males: P < 0.001; females: P < 0.01). Overall, alpha wave differences were not significant among plant types, and live plants elicited a trend toward emotional stability. These findings suggest that 3D plant models can be as effective as real plants in psychophysiological applications, indicating their potential benefits for enhancing mental health in urban environments.
The plant nursery industry in Oregon faces increasing challenges from climate change, particularly concerning the cultivation of shade trees grown in nursery production. Shade trees are multimillion-dollar agricultural commodity in Oregon, the number one producer of shade trees in the United States. Oak, maple, and sycamore are common examples of shade trees. Our hypothesis posited that despite being commonly cultivated together in shade-tree production blocks under similar management protocols, these trees employ distinct hydraulic strategies during growth. The aim of this research was to investigate the physiological response of Sunset Red Maple (Acer rubrum ‘Franksred’) and Red Oak (Quercus rubra) to variations in soil moisture and vapor pressure deficit (VPD). The research was carried out at the experimental field-grown nursery located at the North Willamette Research and Extension Center in Aurora, OR, USA. Stomatal conductance (g s) and stem water potential (ψs) were measured to assess plant responses to soil moisture and VPD. When soil moisture was abundant, average Red Oak g s was 0.26 ± 0.13 mmol·m−2·s−1, twice as great as Red Maple, at 0.12 ± 0.09 mmol·m−2·s−1. Red Oak g s was 2.67 times greater than Red Maple g s under soil moisture deficit. Similarly, at any given soil moisture content Red Oak ψs was significantly less negative (−6.22 ± 2.70 bars, n = 384) compared with Red Maple (−12.15 ± 4.45 bars, n = 384). In general, our results revealed distinct responses between the two species, with Red Maple exhibiting greater sensitivity to soil moisture and VPD compared with Red Oak. Furthermore, we observed an important correlation between VPD and maple g s, with g s, decreasing in response to increasing VPD whether soil moisture was abundant (R 2 = 0.64) or lacking (R 2 = 0.69), highlighting the importance of considering atmospheric moisture dynamics in plant water management strategies. These findings underscore the complexity of plant responses to drought and emphasize the necessity of informed water management practices for sustainable nursery production. This research contributes to our understanding of plant hydraulic physiology and provides valuable insights for sustainable nursery management practices, particularly in the face of climate change–induced droughts.