Optimizing Plants and Cultivation System for Controlled Environment Agriculture (CEA)

Defoliation (leaf removal or pruning) is a common practice in tomato production that makes crops more manageable, prevents conditions conducive to fungal attack and increases the exposure of the fruit to light, especially in winter conditions. The intensity and frequency of leaf removal on commercial farms often vary according to workforce availability criteria, which makes it difficult to determine their effect on tomato crop yields. It would be reasonable to think that a reduction in leaf area influences radiation interception and, therefore, the production of assimilates and biomass. However, in intensive production systems with a high leaf area index (LAI), leaf pruning can increase radiation interception, either by reducing competition between productive and vegetative organs or by increasing radiation use efficiency. This study was therefore designed to assess the effect of different intensities and frequencies of basal leaf removal on dry matter production and partitioning between the different organs of the plant, and thus on tomato crop productivity. A series of trials were conducted over three consecutive seasons, with a trial conducted per season: (a) Trial 1: leaf removal control—LRC (with leaves removed from the base to two leaves below the truss close to harvest, T0) was compared with LR1 (leaf removal from the base to two leaves below the truss above T0, i.e., T1) and LR2 (two trusses above T0 (T2)); (b) Trial 2: LRC compared with LR2 and LR4 (four trusses above T0 (T4)), carried out at two frequencies; and (c) Trial 3: LRC compared with an intense leaf removal treatment (LRI) whereby between 10 and 12 leaves were left on each stem. LAI saturation values under our conditions were found to be around 2.0. No significant differences in yield were found between the control and treatments LR1, LR2 and LR4, with a reduction in the number of leaves of up to 35% and LAI values during harvest above 2.0. The intense leaf removal treatment (LRI), which reduced the number of leaves by 47% and the LAI value from 2.8 to 1.5 compared to the control, resulted in a 15% reduction in dry biomass and a 17% decrease in fruit yield. Full article

‘Xinomavro’ (V. vinifera L.) is an important native red wine grape variety in Northern Greece, particularly in PDO (protected designation of origin) regions. Despite its significance, there is limited research on the effects of pruning type and severity on ‘Xinomavro’ vine physiology, yield, and berry quality across diverse environmental conditions. This study aimed to address this knowledge gap and provide growers with crucial information for optimizing vineyard management practices. The study was conducted over two consecutive years (2016 and 2017) in a vineyard in Thessaloniki, Northern Greece. Four treatments (B12: 12 buds on 6 spurs, B24: 24 buds on 12 spurs, M12: 12 buds on 2 canes, and M24: 24 buds on 4 canes) combining two bud load levels (12 or 24 count nodes) and two pruning types (short spurs or long canes) were applied to ‘Xinomavro’ vines in a complete block randomized design. The vine water status, gas exchange, canopy characteristics, yield components, and berry composition were measured. Bud load and pruning type significantly influenced vine canopy development, microclimate, and yield components. Short pruning with high bud load (B24) resulted in denser canopies and higher yields, whereas cane pruning (M12 and M24) led to more open canopies and improved berry quality indicators. Treatment effects on berry composition were inconsistent across years but showed a tendency for higher anthocyanin and total phenol content in cane-pruned vines. This study demonstrates that pruning type (short or long fruiting units) may have a greater impact on vine growth, yield, and berry composition than bud load alone in ‘Xinomavro’ vines. Cane pruning appears to be a more effective strategy for achieving vine balance and potentially improving grape quality under given experimental conditions. Full article

Increasing wheat (Triticum aestivum L.) planting density is the most effective production management method for increasing yields; however, excessive crop populations under high planting densities may experience elevated risk of stem lodging. We conducted this study to assess the relationship between reduced lodging and increased yield, investigate the effects of planting density on wheat population structure, stem strength, and material transport, and provide a basis for rationale planting densities. The experiments were carried out using a split-plot design with three replicates. The main plots contained two wheat varieties: Bainong 5819 (BN5819) and Bainong 4199 (BN4199), and the sub-plots contained four planting density treatments: 90 × 10⁴ plants/ha (D1), 180 × 10⁴ plants/ha (D2), 270 × 10⁴ plants/ha (D3), and 360 × 10⁴ plants/ha (D4). A two-year field trial was conducted in 2021–2023. The relationships between population structure characteristics, changes in stem strength, activation, and retransport of stem material after anthesis, and achievement of high and stable yields were investigated at the different planting densities. When the planting density of wheat increased from D1 to D4 treatment, the activity of fructan hydrolase was significantly increased. Compared with D1 treatment, the highest activity of fructan hydrolase was increased by 457.47 μg/h/g under D4 treatment. At the same time, the increase of density also increased the contribution rate of dry matter accumulation (CDMA) to grain after anthesis increased, with the highest increase in CDMA at 33.67%, which significantly reduced stem strength. Correlation analysis revealed a significant negative association between CDMA and stem strength. Specifically, CDMA levels were significantly lower with the D3 treatment than the D4 treatment, while stem strength remained higher after anthesis as an adaptive response to mitigate lodging risk. Stem storage compounds can promote grain filling and a weight increase in inferior grains. The number of spikes per unit area increased significantly with increasing planting density, but the number of grains per spike and 1000-grain weight decreased significantly. In two years, the number of spikes in D3 treatment increased by a maximum of 211.67 × 10⁴ ha⁻¹ and 99.17 × 10⁴ ha⁻¹, respectively, compared to D1 and D2 treatments. The number of grains per spike was significantly higher than that of D4 treatment, the highest being 3.68 grains. Therefore, in the North China Plain with suitable water, fertilizer, and temperature, the sowing density of 270 × 10⁴ plants/ha established population structure, significantly reduced CDMA, maintained post-anthesis stem strength, enhanced resilience of stems against post-anthesis lodging, and resulted in high yields by stabilizing the number of grains per spike and increasing the number of wheat spikes. Full article

Improving edible biomass space use efficacy (EBSUE) is important for sustainably producing edamame and dwarf tomatoes in plant factories with artificial light. Photosynthetic photon flux density (PPFD) may increase EBSUE and space use efficacy (SUE). However, no study has quantitatively explained how PPFD affects EBSUE in edamame and dwarf tomatoes. This study aimed to quantitatively validate the effects of PPFD on EBSUE in dwarf tomatoes and edamame and verify whether this effect differs between these crops. The edamame and dwarf tomato cultivars ‘Enrei’ and ‘Micro-Tom’, respectively, were cultivated under treatments with PPFDs of 300, 500, and 700 µmol m⁻² s⁻¹. The results showed that the EBSUE and SUE increased with increasing PPFD in both crops. The EBSUE increased depending on the increase in SUE, the dry mass ratio of the edible part to the total plant in the edamame, and the SUE only in the dwarf tomatoes. In conclusion, a high PPFD can improve the EBSUE and SUE of edamame and dwarf tomatoes in different ways at the reproductive growth stage. The findings from this study offer valuable information on optimizing space and resource usage in plant factories with artificial light and vertical farms. Additionally, they shed light on the quantitative impact of PPFD on both EBSUE and SUE. Full article

We investigated the effect of supplemental CO₂, gibberellic acid (GA₃), and light on the quality and yield of Humulus lupulus L. strobili (cones). When applied separately, CO₂ and light increased the yield by 22% and 43%, respectively, and had a significant effect on the components of cone mass and quality. Exogenous GA₃ increased flower set; however, the yield decreased by approximately 33%. Combining CO₂, GA₃, and light, and any combination thereof, resulted in significant increases in flower set and cone yield enhancement compared to separate applications. A synergistic effect occurred when some factors were combined. For example, the combination of CO₂ and light resulted in a yield increase of approximately 122%. The combination of all three resources, CO₂, GA₃, and light, resulted in an approximate 185% yield increase per plant. Thus, in comparison to the addition of one supplementary resource, a greater increase in yield resulted from the combination of two or more supplemental resources. Flower set stimulation due to GA₃ decreased cone alpha- and beta-acid quality attributes, unless combined with CO₂ and light as additional carbohydrate-generating resources. Additional research is needed to close the hop yield gap between current hop yields and the achievement of the plant’s genetic potential. Full article

Light intensity significantly influences plant growth in hydroponic green fodder systems, yet research exploring the growth dynamics and nutrient accumulation in hydroponically grown barley under various light conditions has been limited. This study investigated the impact of different light intensities—0, 100, 200, and 300 μmol/m²/s—on the nutritional composition and quality of hydroponic barley fodder. Assessments were made on biomass production, physiological responses including photosynthetic parameters, and nutritional components such as essential amino acids five days post-treatment. The findings indicated that increasing light intensity boosted photosynthetic activity, expanded leaf area, enhanced root length, and promoted biomass accumulation. However, the highest intensity tested, 300 μmol/m²/s, led to significant chlorophyll degradation, increased water loss, and induced oxidative stress, adversely affecting fodder quality and reducing essential amino acids. In contrast, an intensity of 200 μmol/m²/s was identified as optimal for promoting robust barley growth through principal component analysis. This optimal setting supported vigorous growth and ensured the production of nutrient-rich, high-quality fodder, providing a basis for scaling up production efficiently. This research offers crucial insights into optimizing light conditions to maximize both the yield and nutritional quality of hydroponically grown barley fodder, presenting a significant step forward in enhancing hydroponic farming practices. Full article

Rootstocks serve as a strategic tool for grapevine adaptation to specific biotic and abiotic conditions and for managing vine growth, grape yield, and berry composition in commercial vineyards. This study investigates the influences of four different rootstock varieties (101-14 MGt, 3309 C, 110 R, and 140 Ru) on the viticultural performance of ‘Xinomavro’ vines, a prominent Greek red winegrape varietal. By conducting a two-year field experiment using various rootstocks, we assessed parameters related to water status, vegetative growth, yield, and berry composition. Our results revealed that rootstock selection has a significant impact on vine development, especially in terms of berry size and the concentrations of secondary metabolites. Principal component analysis confirmed the complex interaction between rootstock vigor and vine productivity. This study underscores the importance of rootstock variety in manipulating grapevine characteristics, particularly for the ‘Xinomavro’ variety, in response to regional climatic conditions. Full article

Tamarisk witches’ broom, yellowing, and little leaf symptoms were observed during 2018–2023 surveys of rural deserts in central regions of Iran with the highest disease incidence up to 72% in Chah Afzal (Yazd province). A verification of the presence and identity of phytoplasmas associated with these symptoms was then performed. Tamarisk tree branch cuttings obtained from symptomatic plants sprouted up to 90.3% but with 15–25 days’ delay compared to the asymptomatic ones and showed internode shortening and witches’ broom, while the branch cuttings from asymptomatic plants had normal growth and sprouted up to 97.8%. Phytoplasma transmission by dodder bridges to periwinkle did not succeed, while nested polymerase chain reaction on the phytoplasma ribosomal gene followed by RFLP and phylogenetic analyses revealed the presence of ‘Candidatus Phytoplasma asteris’, ‘Ca. P. australasiae=australasiaticum’, and ‘Ca. P. trifolii’ (ribosomal subgroups 16SrI-B, 16SrII-D, and 16SrVI-A, respectively) in the samples from symptomatic plants only. Further amplifications were performed on selected phytoplasma-positive samples on tuf and secA genes, and the produced sequences indicated the presence of mixed phytoplasma infection in some of the samples. In particular, in the tuf gene, a mixed infection of ‘Ca. P. australasiae=australasiaticum’ and ‘Ca. P. trifolii’ was detected, while in the secA gene, the presence of ‘Ca. P. asteris’ or ‘Ca. P. tritici’ strains was identified. The first-time detection of diverse phytoplasma strains in symptomatic T. aphylla suggests that this species represent a relevant source of infection for the agricultural crops and for landscape plants especially when temperature allows insect vector transmission, and therefore, it represents a risk in every environment especially in the frame of climatic changes. Full article

A three-year study was conducted to investigate the effects of two timings—at berry set and at veraison—of post-bloom leaf removal (LR) applications from the basal sections of the shoot on the growth, yield, and berry composition of Vitis vinifera L. cv. Xinomavro, the major red winegrape of North Greece. LR at berry set drastically reduced yield by affecting all its components while increasing the ratio of secondary foliage per total leaf area. LR at veraison had a milder effect on growth and yield. Both treatments increased sugar and phenolic compound levels in berries, while early LR increased the contribution of more stable forms of anthocyanins. Additionally, early LR increased the skin-to-pulp ratio, suggesting that it could be an effective viticultural technique for more concentrated red wines. Overall, both LR timings improved most of the berry attributes compared to the non-treated vines; however, the earlier application can be recommended when aiming at the production of deep-colored and richly flavored wines. Full article

The total land used for land-based food farms is less than 1% in Singapore. As a result, more than 90% of Singapore’s food needs are imported. To strengthen food security, Singapore has set a target to develop the capability and capacity of the agri-food industry to locally produce 30% of its nutritional needs by 2030. To achieve this goal, technology is the key to helping farms to “grow more with less”. This review first discusses how aeroponic systems have been adapted for growing all kinds of leafy vegetables in the tropics through the manipulation of root-zone temperature and heat priming to save power energy. Growing vegetable crops indoors and in greenhouses not only allows the growers to achieve high productivity but also enables them to enhance nutritional values. The second part of this paper emphasizes how to achieve substantial yield through deficit irrigation with higher nutritional quality in a cost-effective manner. Growing crops vertically has become increasingly popular, as it increases land use. We establish a commercially viable LED-integrated aeroponic system to grow vegetables vertically. The last part of the paper discusses the impacts of LED spectral quality, quantity, and duration on vegetable production. Full article

The sunlight greenhouse crops receive varies and is often insufficient for consistent year-round growth in greenhouses. Supplemental lighting is commonly applied in winter, but this practice has a significant energy cost, accounting for 10–30% of operating expenses and impacting greenhouse profitability. Greenhouse lights are traditionally adjusted based on sunlight intensity to meet crops’ daily light requirements. However, if plants can withstand lower daily light integrals (DLI) after a sunny day without reducing the growth, there is potential to reduce the energy required for supplemental lighting and increase the profit. To determine whether excess light received one day can be ‘carried over’ to the next, we grew oakleaf lettuce (Lactuca sativa ‘Green Salad Bowl’ and ‘Red Salad Bowl’) under six lighting regimes inside a vertical farm. Plants in all treatments received an average DLI of 15 mol·m⁻²·d⁻¹, but DLIs alternated from day-to-day (15/15, 17.5/12.5, 20/10, 22.5/7.5, 25/5, and 27.5/2.5 mol·m⁻²·d⁻¹), resulting in DLI fluctuations from 0 to 25 mol·m⁻²·d⁻¹. Plants had similar leaf area (~800 cm²/plant) and dry weight (~1.8 g/plant) when grown with DLI fluctuations from 0 to 15 mol·m⁻²·d⁻¹, while higher DLI fluctuation reduced growth. To confirm this DLI “carrying-over” effect on plants grown under sunlight with supplemental light, we conducted a second study in a greenhouse with ‘Green Salad Bowl’ lettuce. In this study, plants were grown with five different DLI fluctuations (15/15, 16.75/13.25, 18.5/11.5, 20.25/9.75, and 22/8 mol·m⁻²·d⁻¹), ranging from 0 to 14 mol·m⁻²·d⁻¹, while maintaining an average DLI of 15 mol·m⁻²·d⁻¹ in all the treatments. We observed similar leaf area (~750 cm²/plant) and dry weight (~1.8 g/plant) in lettuce plants grown with DLI fluctuations from 0 to 10.5 mol·m⁻²·d⁻¹. Higher DLI fluctuations reduced growth. Hence, carrying excess light from a sunny to an overcast day is possible within limits. Our study concluded that the DLI requirement can be reduced by approximately 5.25 mol·m⁻²·d⁻¹ on the day following a sunny day. By analyzing historical weather data from five US locations, we quantified the potential annual energy savings from incorporating this ‘carrying-over DLI’ concept. This approach resulted in annual energy savings of approximately 75–190 MWh/ha in greenhouse lettuce production. Such reductions in supplemental lighting energy will enhance the profitability and sustainability of the greenhouse industry. Full article

Experimental studies were conducted on the cultivation of tomatoes (Solanum lycopersicum L.) at Shandong Agricultural University, China, from 2022 to 2023. Three cultivation patterns were designed as follows: a north–south orientation with a row spacing of 1.40 m (NS-1.4m), a north–south orientation with a row spacing of 1.80 m (NS-1.8m) and an east–west orientation with a row spacing of 1.80 m (EW-1.8m). A functional–structural plant model using the open source interactive modeling platform of GroIMP was constructed for the cultivation of tomatoes. The growth of plants as well as the light distribution and light interception capacity of the crop canopy were simulated and analyzed. The impacts of these cultivation patterns on the growth, photosynthetic characteristics, fruit ripening time, quality and yield of tomato plants were analyzed. The studies revealed that compared with the NS-1.4m treatment, the canopy light interception of tomato plants under the NS-1.8m and EW-1.8m treatments increased by 6.08% and 9.80% in a winter–spring crop and 6.80% and 19.76% in an autumn–winter crop, respectively. Their plant height, leaf area, aboveground dry matter accumulation, leaf net photosynthesis rate as well as the lycopene, vitamin C and sugar–acid ratio of the fruit all exhibited increasing trends, while fruit ripening was accelerated. The yield of the NS-1.8m and EW-1.8m treatments increased by 3.92% and 6.18% in a winter–spring crop and 4.17% and 9.78% in an autumn–winter crop, respectively. Structural equation modeling was used to further analyze the data, confirming that the cultivation of an east–west orientation with wide row spacing is beneficial for tomato cultivation in Chinese solar greenhouses. This cultivation pattern maximizes the canopy’s light interception, thus leading to improved fruit quality and yield. Overall, this study provides valuable insights for optimizing the cultivation pattern of solar greenhouse crops. Full article

Ensuring the technical and technological possibility of regularly obtaining fresh, high-quality plant production in Antarctic stations is an urgent task of our time. This work is devoted to studying the growth and development of leaf vegetable crops and the main quality indicators of their edible parts when grown in the phytotechnical complex greenhouses at the “Vostok” Antarctic station and at the agrobiopolygon of the Agrophysical Research Institute (AFI). The plants, belonging to 13 varieties of 9 types of leaf vegetable crops (arugula, garden cress, cabbage, mustard, leaf radish, leaf lettuce, amaranth, dill, parsley leaf), were studied during five growing seasons at the “Vostok” station and at the AFI agrobiopolygon under controlled conditions (control). The experimental data obtained demonstrate the high productivity of the phytotechnical complex for most of the investigated crops per unit of useful area, with lower costs of electricity and water consumption per unit of production compared with a number of greenhouses at foreign Antarctic stations and greenhouse complexes with controlled conditions located on other continents. Lettuce crops were the most adapted to the growing conditions at the Antarctic station “Vostok”. They did not differ in their evaluated characteristics from the control. All other investigated crops, while not differing in their development rate and quality, had statistically significant (16–61%) decreases in their yield per 1 m² per year. This may demonstrate the difference in the “genotype–environment” interaction in plants grown at the Antarctic station and AFI agrobiopolygon, probably due to the different barometric pressure and partial pressure of oxygen at the two locations. The positive psychological effects of the greenhouses were identified along with nutritional and other qualities of the plants. Full article

Lilies are important crops that are commonly used as cut flowers (Lilium spp.) and edible bulb crops (Lilium davidii var. unicolor). However, virus infections can significantly impact the quantity and quality of lily production. Various methods have been developed to eliminate viruses in lilies, including in vitro culture and virus detection techniques. Meristem culture is the most effective method, which can be combined with other techniques such as thermotherapy and chemotherapy. Nonetheless, virus elimination is affected by several factors, including cultivar, explants used, virus type, and duration of treatments. Efficient diagnostic methods, such as serological and molecular techniques, have been developed to detect viral infections in lilies, including enzyme-linked immunosorbent assay (ELISA) and real-time reverse transcriptase polymerase chain reaction (real-time RT-PCR). However, cross-contamination and multiple-virus contamination can lead to unreliable results, and more sophisticated protocols and systems have been developed to address these issues. The objective of this review is to provide a comprehensive overview of the development of lily virus eradication, detection strategies, challenges, and solutions associated with these procedures, and how more sophisticated approaches such as multiplex RT-PCR, indirect ELISA (ID-ELISA), immunocapture RT-PCR (IC-RT-PCR), and immunochromatographic test strips (ICSs) can alleviate some of these setbacks. Full article

Soilless cultivation represents a promising method for the future of the horticulture industry as it offers advantages such as improved quality control over the growth environment and mitigation of uncertainties related to soil, water, and nutrient availability. In this study, we aimed to investigate the effects of different environments, specifically greenhouse (GH) and open-field (OF), on the growth, phenotypic characteristics, physio-biochemical properties, qualitative parameters, and antioxidant capacity of strawberries cultivated using a soilless system. The aforementioned parameters were measured in both the GH and OF settings. Our findings revealed that the growth, yield, and morphological parameters were significantly higher in the GH environment compared to the OF. However, when considering fruit quality indices such as fruit texture firmness, fruit dry matter percentage, taste index (TSS/TA ratio), and post-harvest shelf-life, the OF cultivation method exhibited significantly superior results. Moreover, various aspects, related to plant physiology and biochemistry, antioxidant enzyme activity, total antioxidant capacity (DPPH), vitamin C content, and secondary metabolites, were found to be significantly higher in the OF environment compared to the GH. Overall, the results of our study suggest that OF soilless cultivation outperforms GH cultivation in terms of fruit quality, antioxidant capacity, and post-harvest shelf-life. Despite the observed decrease in fruit growth and yield, soilless strawberries grown in OF are likely to yield a final product of higher quality and nutritional value compared to those cultivated in a GH environment. These findings highlight the potential of OF soilless cultivation as a viable approach for strawberry production, emphasizing the importance of considering not only yield but also qualitative aspects and the nutritional value. Further exploration and optimization of soilless cultivation techniques in OF settings could contribute to the advancement of sustainable horticultural practices. Full article

Efficient water management is crucial for sustainable agriculture and water resource conservation, particularly in water-scarce regions. This study investigated the effect of different irrigation depths on onion (Allium cepa L.) yield and water use patterns in a semi-arid tropical region of Colombia, using a completely randomized design with five treatments. The treatments ranged from 0–100% of total available water (TAW), T1 (100% of TAW), T2 (80% of TAW), T3 (60% of TAW), T4 (40% of TAW), and T5 (20% of TAW). The experiment was conducted in a greenhouse during one growing season (2022–2023). The normalized water productivity (WP *), irrigation water productivity (IWP), consumptive water productivity, blue water footprint (WF_blue), marginal water use efficiency (MWUE), and elasticity of water productivity (EWP), as well as some parameters of quality onion, were determined. The soil in the experimental field was classified as sandy loam; the results show that the WP * of onion is 17.42 g m⁻², the water production function shows the maximum production will be achieved at a water application depth of approximately 943 mm, and beyond that, the biomass yield will decrease with additional water application, IWP values for onion ranged from 2.18 to 3.42 kg m⁻³, the highest Wf_blue was in T5 (34.10 m³ t⁻¹), and low Wf_blue was T1 (20.95 m³ t⁻¹). In terms of quality, treatment T1 had the most favorable effects on bulb weight, polar diameter, and equatorial diameter, while treatment T5 had the least favorable effects. The study highlights the importance of efficient irrigation on sandy loam soils to maximize yield and water use efficiency. It provides valuable data for evaluating the potential yield benefits of precision irrigation in the study area. Optimizing irrigation depth can significantly improve onion yield and water use efficiency in semi-arid regions. Full article