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Health and quality of the root system are imperative to ensure the successful establishment of a citrus tree after transplant from the nursery into the field. Containerized citrus production in enclosed nurseries restricts root growth and can result in root circling and intertwining. This may hinder root expansion and result in root girdling after transplant, negatively affecting tree establishment and growth. The root structure of a transplanted citrus tree can also be affected by the container type used in the nursery. Containers with root-pruning properties like chemical pruning or air pruning reduce root circling and may produce superior root systems compared with regular, nonpruning containers. The aim of this study was to evaluate the effects of different nursery containers on root physiological and morphological traits and plant performance over 15 months of growth in the nursery. Three container types, chemical pruning containers, air-pruning containers, and standard nursery containers, were compared. The chemical pruning containers were standard citrus nursery containers with a mixture of copy hydroxide [Cu(OH)2] and copper carbonate (CuCO3) [10% copper (Cu)] applied to the inner wall. Pruning occurs upon contact of the roots with the Cu on the wall of the containers. The air-pruning containers were custom-sized Air-Pots in which pruning occurs on holes in the wall of the containers upon contact of the roots with the air. Two rootstocks, US-812 and US-942 (Citrus reticulata × Poncirus trifoliata), were included for comparison in the nongrafted stage and 12 months after grafting with ‘Valencia’ orange (Citrus sinensis). Chemical root pruning positively influenced tree height, shoot mass, leaf area, rootstock trunk diameter, and the nonfibrous root biomass. No differences among container types were observed for the fibrous root biomass, but chemical pruning produced more roots that were finer with a higher specific root length and a higher respiration rate. In contrast, air pruning produced more roots that were thicker compared with the other containers. Most of the leaf nutrients were lower in trees grown in the chemical pruning containers compared with the standard containers, except for Cu and zinc (Zn), which were highest in the former. Trees growing in air-pruning containers were not significantly different in growth from trees growing in standard containers.

Open Access

The nursery industry produces and sells plants for landscape and environmental purposes and represents a major sector within the US agricultural industry. In recent years, the nursery industry has undergone rapid growth as a result of various factors, including increased demand from housing development and pandemic-fueled interest in home horticulture. As with any industry, the nursery industry must adapt to changes in societal trends to sustain growth. In the wake of unprecedented societal and supply chain issues stemming from the global coronavirus disease 2019 pandemic, the American Society for Horticultural Science Nursery Crops Professional Interest Group gathered experts in various disciplines to provide their opinions and insights into the future of the nursery industry, focusing specifically on the changes and challenges the nursery industry will face in the coming decade. Nursery crop specialists spanning the United States identified three primary areas that will steer the future momentum of the nursery industry: consumer trends, natural resources, and labor. Six experts were selected to represent these areas in a workshop held Jul 2022 at the American Society for Horticultural Science Annual Conference in Chicago, IL, USA. This article was developed to disseminate to the greater scientific community the discussions held and insight shared during that workshop.

Open Access

In an effort to mitigate the environmental impact of chemical fertilizers, plant growth-promoting rhizobacteria (PGPR) have emerged as a more sustainable alternative. Streptomyces saraceticus 31 (‘SS31’), a new strain of biocontrol bacteria, was inoculated into rhizosphere soils of ‘Benifuji’ grape to evaluate its impact on grape roots and berries. The results indicated significant improvements in soil fertility, with higher levels of organic matter, phosphorus, potassium, and nitrate nitrogen compared with those of the controls. Moreover, ‘SS31’ application elicited a notable reduction in soil pH levels, along with a substantial augmentation in the enzymatic activities of both phosphatase and invertase. The grapes treated with ‘SS31’ exhibited a notable increase in the number, length, surface area, and volume of fine roots in both 0- to 10-cm and 10- to 20-cm soil profiles. The application of ‘SS31’ resulted in the observation of greater diameter, lower density, and larger lumen area, along with increased specific hydraulic conductivity in the vessels of roots with 1- to 2-mm diameters. Despite a slight reduction in berry weight compared with that of the controls, ‘Benifuji’ grape berries displayed higher total soluble solids and lower total titratable acidity after ‘SS31’ application. Furthermore, ‘SS31’ treatment elevated the levels of volatile compounds in berries, especially fatty acid-derived compounds. A network analysis revealed a robust positive correlation between the observed improvements in grape berry quality and the morphology as well as the hydraulic conductivity of the grape fine roots. In conclusion, these findings suggest that ‘SS31’ has the potential to enhance grape root function by expanding the root absorption area and facilitating water transportation. This, in turn, may improve the flavor and aroma of ‘Benifuji’ grape berries.

Open Access

Turfgrass seed, a living organism, is facing more stringent trade regulations compared with nonliving products. We applied multiple empirical approaches to explore the impact of these regulations on trade flows in grass seeds. We constructed a series of novel variables to measure these regulations, such as environment regulation stringency, pre-shipment inspections, market conditions, and product requirements. Our results showed that nontariff trade measures had substantial impacts on the trade of grass seeds. These measures sometimes worked as barriers to trade and at other times worked as catalysts for trade.

Open Access

In temperate climates, aquaponic producers must use artificial lighting; however, purchasing light-emitting diode (LED) grow lights can be cost-prohibitive. Two aquaponic trials evaluated low-cost LED lighting for the growth of bibb lettuce (Lactuca sativa var. capitata). In trial 1, seven low-cost LED lights were screened and compared with a high-end LED grow light. The three best-performing lights in terms of total plant biomass produced (grams) and total plant biomass per unit of electricity (grams per square meter per kilowatt-hour) were more intensively evaluated in trial 2. These lights included Spider Farmer SF-2000 [SPI ($300)], Fluence RAZRx [FLU ($364)], Designers Fountain 6-Light 5000 K LED High Bay Light [DES ($100)], and the control NeoSol DS [NEO ($1400)]. After 17 days, lettuce grown under NEO achieved higher (P ≤ 0.05) total biomass (939 g) than DES (812 g). There were no differences (P > 0.05) in the average individual plant weights in any treatment. Plant production efficiency (grams per square meter per kilowatt-hour) was higher in DES than NEO (P ≤ 0.05) but was not different from SPI and FLU (P > 0.05). Results indicate that low-cost LEDs are a viable option for producers looking to reduce investment costs while maintaining adequate plant growth. To further describe potential cost savings for producers, a partial budget analysis evaluated the net change in profits and benefit/cost ratio (BCR) of the experimental lights. All showed improved economic results compared with the control (NEO). These studies indicate that low-cost LED lights can support similar plant growth, at higher energy efficiencies, with better economic viability than more expensive grow lights.

Open Access

We investigated the growth dynamics of hydroponic lettuce (Lactuca sativa) driven by the influence that potassium (K+) has on crop growth. This study aimed to determine whether increased K+ concentrations under different daily light integrals (DLIs) in a hydroponic system will boost growth of greenhouse lettuce. This study was conducted within a controlled glass greenhouse environment with varying DLIs achieved by integrating an adaptive lighting control system over a 16-hour photoperiod. We used three K+ treatments of 200, 400, or 600 mg⋅L−1 K+ and six DLI lighting treatments of 11.1, 12.9, 14.6, 15.9, 16.9, and 17 mol⋅m−2⋅d−1. We found that increasing K+ did not increase shoot dry weight, leaf area, or specific leaf area with increasing DLIs. Although K+ and DLI had an interacting effect on the root dry weight fraction, leaf chlorophyll content, and quantum yield of photosystem II, the K+ treatments did not increase or decrease with increasing DLIs. The influencing factor was DLI, which led to increases in shoot dry weight and leaf area, whereas a decrease in specific leaf area was observed with increasing DLIs. Ultimately, adding supplemental concentrations of K+ did not enhance lettuce growth, nor did these effects show any increase with increasing DLIs.

Open Access

Limited preemergence herbicides are registered for new blackberry (Rubus subgenus Rubus) plantings. This greenhouse experiment was designed to investigate the effects of a broad selection of preemergence herbicides at multiple rates on blackberry transplants. Screening was initiated Aug 2021 and repeated Mar 2022 in Fayetteville, AR, USA, in a greenhouse at the Milo J. Shult Agricultural Research and Extension Center. ‘Ouachita’ blackberry plugs were transplanted into utility pots that contained field soil and growth media treated with preemergence herbicides. After transplanting, plant height was measured from the substrate to the highest apical meristem of 25 representative plants. Initial blackberry plant heights were 13.5 and 9.2 cm in 2021 and 2022, respectively. Twenty-five treatments were evaluated, consisting of 12 preemergence herbicides at 1× and 2× field rates, and one untreated control. Herbicide treatments included diuron, flumioxazin, halosulfuron, indaziflam, mesotrione, napropamide, oryzalin, pendimethalin, rimsulfuron, S-metolachlor, simazine, and sulfentrazone applied to substrate in containers at their respective 1× or 2× field rates. Data were collected on plant height, blackberry injury ratings, internode length, leaf chlorophyll content, and destructive harvest, including leaf count, leaf dry biomass, and aboveground dry biomass. Specific leaf areas and leaf area-to-dry matter ratios were calculated. When observed, plant injury tended to increase from 7 days after treatment (DAT) until 42 DAT. Greater injury levels were observed in response to treatment with mesotrione at the 1× (78%) and 2× rates (90%), halosulfuron at the 1× rate (58%), halosulfuron at the 2× rate (68%), and diuron at the 2× rate (73%). Injury from diuron was rate dependent, with the 1× rate causing relatively low injury (19%). At both the 1× and 2× rates, flumioxazin, indaziflam, napropamide, S-metolachlor, and pendimethalin treatments exhibited similar responses to the untreated control.

Open Access

Two eggplant cultivars (Brigitte and Dalong) were stored under ambient conditions for 8 days to examine the postharvest quality and shelf life. Results indicated that the respiration rate, firmness and springiness, and nutritional quality of both eggplant cultivars decreased with the extension of shelf life. On the contrary, opposite trends were observed in weight loss, gumminess, and chewiness of eggplant fruits. In addition, the weight loss of ‘Brigitte’ eggplant fruits was 3.3% and 6.9% lower compared with ‘Dalong’ eggplant fruits at 4 and 8 days after storage. Thicknesses of epidermal cells and the stratum corneum, the epicuticular wax content of ‘Brigitte eggplant fruits increased by 42.9%, 766.7%, and 58.8% compared with ‘Dalong’ eggplant fruits, respectively, with a concomitant increase in the dense wax layer structure. In conclusion, the storage tolerance of ‘Brigitte’ eggplant fruits was higher than that of ‘Dalong’ eggplant fruits due to the higher epicuticular wax content and dense wax layer structure.

Open Access