Natural products are one of the resources for discovering novel pesticide leads. Here, by molecular hybridization between the natural enamino diketone skeleton and the reported herbicide lead compound I, a series of 3-(1-aminoethylidene)-6-methyl-2H-pyran-2,4(3H)-dione derivatives (APD) were rationally designed, synthesized and tested for herbicidal activity in a greenhouse. The bioassay results showed that most of the target compounds possessed good herbicidal activity under pre-emergence conditions, of which the analog APD-II-15 displayed good pre-emergent herbicidal activity against Abutilon theophrasti Medicus, Amaranthus retroflexus L., Echinochloa crus-galli, Eragrostis curvula (Schrad.) Nees, Avena fatua L., Cyperus difformis L., Chenopodium album L., Ixeris denticulata, Plantago asiatica L., Capsella bursa-pastoris (Linn.) Medic and Flaveria bidentis (L.) Kuntze with > 60% inhibition even at a dosage of 187.5 g ha⁻¹, and displayed good crop safety for wheat, soybean, millet and sorghum at a dosage of 375 g ha⁻¹. The preliminary study of the molecular mode of action by RNA sequencing suggested that a growth inhibition of weeds by APD-II-15 might result from the disruptions of carbon metabolism and formation of a cytoskeleton. The present work indicated that APD-II-15 might be used as a novel herbicidal lead compound for further optimization. Full article

In crops, drought stress reduces the photosynthetic rate and gamete function through oxidative damage. Earlier studies showed that nanoceria possesses an antioxidant property; however, the ability of nanoceria to alleviate drought-stress-stimulated oxidative damage in pulse crops has not been studied. Therefore, experiments were conducted to assess the impacts of nanoceria on drought-induced oxidative damage in mungbean [Vigna radiata (L.) Wilczek]. We hypothesize that foliar application of nanoceria under drought stress can scavenge the excess produced reactive oxygen species (ROS) due to its inherent properties which could result in increased photosynthesis and reproductive success of mungbean. Three experiments were conducted under well-watered and limited-moisture conditions. The traits associated with oxidative damage, photosynthesis, reproductive success, and yield were recorded. Results showed that for mungbean, the optimum concentration of nanoceria for foliar spray was 100 mg L⁻¹. Field and pot culture experiments showed that foliar application of nanoceria under drought decreased the superoxide radical content (29%), hydrogen peroxide content (28%), and membrane damage (35%) over water spray. Nanoceria increased the photosynthetic rate (38%), pod-set percentage (16%), and seed weight m⁻² (44%) in drought-stressed plants compared to control plants. The increased photosynthetic rate by nanoceria spray under drought stress is associated with lesser oxidative damage and stomatal limitation caused by nanoceria’s inherent ROS-scavenging ability. Hence, foliar application of nanoceria at the rate of 100 mg L⁻¹ under drought stress could increase mungbean seed yield per plant through increased photosynthetic rate and pod-set percentage. Full article

Climate change has a significant impact on the agricultural sector, negatively affecting plants’ growth and development, with predicted strong consequences on food availability in the future. Although we are experiencing more frequent and intense heavy rainfall events, a major contributor to field flooding, there is still not much known about the impact of these events on different crops. In this study, we investigated the effects of waterlogging on a model plant white cabbage (Brassica oleracea var. capitata f. alba), with the aim to follow its response to both single and recurrent short-term (72-h length) waterlogging, as well as to track difference in the sensitivity between plants in different growth stages (38- and 48-day-old plants). In our 22-day experiment, settled under fully controlled conditions (16 h day/8 h night, 25 °C day/20 °C night, 60–70% relative air humidity, 250 µmol m⁻² s⁻¹ photosynthetic active radiation), with the aim to more comprehensively recognize consequences of waterlogging on plants, we measured changes in plants on multiple levels: (i) within its morphological traits (number and length of leaves, leaf area, and blade width), (ii) within chlorophyll fluorescence and multispectral traits (20 parameters), (iii) following the levels of plant stress parameters (salicylic acid, abscisic acid, proline, and total polyphenols), and (iv) following changes in the plants’ elemental and mineral composition. According to our results, white cabbage was shown not to be very sensitive to waterlogging, with only plants exposed to repeated waterlogging showing signs of the congestion stress. These signs, observed in the changes of molecular stress parameters salicylic and abscisic acids, were not so clearly evident at the aboveground level. We did not observe changes in the plants’ morphologies, nor their photosynthetic performance. In addition, removal of waterlogging stress resulted in complete recovery of our model plants, suggesting a prompt adaptation response of white cabbage. With the projected increased frequency of occurrence of flooding events, it will become increasingly more important to recognize crops being highly sensitive to flooding with the aim to try to adapt to the changing climate. Full article

‘Candidatus Phytoplasma prunorum’ is causing ever increasing economic losses through the decline of apricot trees in European countries, e.g., Hungary. In this study, the pathogen was identified from plant tissues and insects by nested-PCR. The insect species were identified via morphology and molecular methods. The incidence of the pathogen was 29.6% in randomly selected apricot trees. Most of the infected trees with symptoms died within a year. These results show that phytoplasma is significantly present and causes damage in the investigated plantations. The only known insect vector of this phytoplasma is the plum psyllid, Cacopsylla pruni, which was regularly encountered in the sampled apricot orchards and in their surroundings. In a two-year study, several adults among the sampled specimens were observed to be infected by the pathogen. This observation further confirms the role of the plum psyllid in vectoring the phytoplasma. All the sampled plum psyllid adults belonged to the ‘B’ biotype. Besides C. pruni, Cacopsylla crataegi was abundant in the samples. Several adults of the latter species were also infected by the pathogen ‘Ca. Phytoplasma prunorum’. The rates of occurrence of this phytoplasma in male and female adults of the two psyllid species appeared to be similar. The examined C. crataegi individuals showed genetic differences from each other and from specimens included in a previous investigation. Full article

Improving soil organic carbon (SOC) has been considered as a “win-win way” for ensuring high crop productivity and mitigating chemical N input. Improving SOC can achieve higher wheat yield and simultaneously improve nitrogen (N) productivity (defined as kg grain produced per kg total N input from both indigenous and applied N). Two treatments were tested for improving SOC level. The manure treatment involved applying manure for 6 successive years, and the EM treatment involved adding peat and vermiculite once, both combined with optimized in-season N management. The performance of these two systems were compared with a traditional farming system (Control, where only straw was returned each season). N fertilizer input under all three treatments was optimized by in-season N management and was increased by 90.1% and 48.1% under EM and Manure treatments, respectively, as compared with Control. The average wheat yield for the EM and Manure treatments was 9.1 and 9.2 Mg ha^–1, respectively, across all three years, which was 18.8% and 19.7% higher, respectively, than that of the Control treatment (7.7 Mg ha^–1). The average chemical N application rates for the EM and Manure treatments were 139 and 146 kg ha^–1, which were 24.9% and 21.1% lower than those of the Control treatment, respectively. The N productivity was 15.1% and 14.9% which was higher under Manure and EM treatments than that of the Control treatment. The high yield and N productivity were attributed to improved aboveground dry matter and N uptake by wheat, with optimal soil N supply of the root zone. The higher stem number and weight seen in individual plants with increasing SOC resulted in larger spikes and grains at harvest. Our results determined that increasing SOC combined with optimal N management achieve low chemical N input and higher grain yield by increasing productive stems and grains per spike for improving wheat individual growth. Full article

Supplying homogenous and suitable airflow schemes were explored in Chinese solar greenhouses, which had a positive impact on the crop yield and quality. This paper provided a multifunctional fan–coil unit system (FCU) to assist in circulating air. This system could collect the surplus heat of daytime air and release it to heat the greenhouse at nighttime. However, the main problem to be faced was the nonuniform airflow distributions. Thus, this paper aimed to optimize and analyze the placement strategy of the FCU system for a Chinese solar greenhouse using the numerical methodology. The computational fluid dynamics model was constructed to evaluate the effect of the FCU system on the airflow field and to uphold its validation. The complex structure of the FCU system was simplified to a fan model by fitting the pressure jump and the air velocity to enhance the practicality of the simulation model. Finally, the coefficient of variation was used to optimize four parameters: the tilt angle, swing angle, height above the ground, and shape of the outlet baffle. The effective disturbance velocity percentage was proposed as the evaluation index to improve the turbulence characteristics. The mean absolute error (MAE) between the measured and simulated values of the air velocity for the two planes was 0.06 m/s and 0.09 m/s, and the root mean square error (RMSE) was 0.08 m/s and 0.11 m/s. The simulated results showed that the coefficient of variation before optimization was 0.76, and the effective disturbance velocity percentages of the planes at 0.7 m and 1.0 m from the ground were 42.73% and 41.02%, respectively. After optimization, the coefficient of variation was reduced to 0.33, and the effective disturbance velocity percentages of the two planes increased to 58.68% and 43.73%, respectively. These results significantly improved the uniformity of the interior airflow field. This paper provides a reference for the design and installation of the FCU system. Full article

The fruit quality and yield of sweet peppers can be effectively improved by accurately and efficiently controlling the growth conditions and taking timely corresponding measures to manage the planting process dynamically. The use of deep-learning-based image recognition technology to segment sweet pepper instances accurately is an important means of achieving the above goals. However, the accuracy of the existing instance segmentation algorithms is seriously affected by complex scenes such as changes in ambient light and shade, similarity between the pepper color and background, overlap, and leaf occlusion. Therefore, this paper proposes an instance segmentation algorithm that integrates the Swin Transformer attention mechanism into the backbone network of a Mask region-based convolutional neural network (Mask RCNN) to enhance the feature extraction ability of the algorithm. In addition, UNet3+ is used to improve the mask head and segmentation quality of the mask. The experimental results show that the proposed algorithm can effectively segment different categories of sweet peppers under conditions of extreme light, sweet pepper overlap, and leaf occlusion. The detection AP, AR, segmentation AP, and F1 score were 98.1%, 99.4%, 94.8%, and 98.8%, respectively. The average FPS value was 5, which can be satisfied with the requirement of dynamic monitoring of the growth status of sweet peppers. These findings provide important theoretical support for the intelligent management of greenhouse crops. Full article

Cold reduces maize (Zea mays L.) production and delays sowings. Cold tolerance in maize is very limited, and breeding maize for cold tolerance is still a major challenge. Our objective was to detect QTL for cold tolerance at germination and seedling stages. We evaluated, under cold and control conditions, 919 Dent and 1009 Flint inbred lines from two nested association mapping designs consisting in 24 double-haploid populations, genotyped with 56,110 SNPs. We found a large diversity of maize cold tolerance within these NAM populations. We detected one QTL for plant weight and four for fluorescence under cold conditions, as well as one for plant weight and two for chlorophyll content under control conditions in the Dent-NAM. There were fewer significant QTL under control conditions than under cold conditions, and half of the QTL were for quantum efficiency of photosystem II. Our results supported the large genetic discrepancy between optimal and low temperatures, as the quantity and the position of the QTL were very variable between control and cold conditions. Furthermore, as we have not found alleles with significant effects on these NAM designs, further studies are needed with other experimental designs to find favorable alleles with important effects for improving cold tolerance in maize. Full article

Intensive greenhouse vegetable production is often associated with a decline of crop productivity due to the increase of soil salinity and/or a reduction of biological fertility. The aim of the current work was to assess the effects of three organic fertilizers on morpho-physiological and agronomic traits of greenhouse lettuce as well as soil enzyme activity under poor soil quality conditions. The tested organic fertilizers (poultry manure, vinasse-based fertilizer, and insect’s frass fertilizer) were applied pre-planting at the same equivalent nitrogen (N) rate (90 kg N ha⁻¹). Laboratory incubation assay results showed that vinasse-based fertilizer was the most suitable fertilizer in supplying the mineral N in the short term. All fertilizers increased shoot fresh and dry weight compared to unfertilized control with a more pronounced effect (+75%) with vinasse-based fertilizer and insect’s frass. Insect frass reduced by 27% the leaf nitrate concentration in comparison with the other treatments. The toxic heavy metal Pb was 46% lower in all organically fertilized lettuce leaves. Soil enzymatic activities of acid phosphatase, alkaline phosphatase, arylsulfatase (ArS), N-acetyl-β-D-glucosaminidase (NAGase), dehydrogenase, and total hydrolase (THA) were enhanced by poultry manure and insect’s frass in comparison with unfertilized control while vinasse-based fertilizer increased ArS, NAGase, and THA. Taken together, our data demonstrate that the application of organic fertilizers especially vinasse-based fertilizer and insect’s frass during intensive crop production is a suitable approach for mitigating the negative impact of soil salinity, enhancing soil biological fertility, and improving agronomic performance of greenhouse lettuce. Full article

A rapid, non-destructive method for nitrate content assessment is essential for a rational wide-scale application of nitrogen in sustainable growing spinach. The method should be effective in facing environmental, genotype, and management variability. The results from three field experiments carried out in Teramo (Italy), during the 2021 and 2022 growing seasons, and by combining nitrogen supply with spinach genotypes, are presented. The spectral canopy reflectance was collected to find out the spectral band relationship with nitrate concentration. Preliminary PCA and mixed linear model analysis showed that nitrate content is among the less detectable features. Unexpected chlorosis onset in one experiment added more variability; nevertheless, spectral regions of blue-cyan and early NIR when combined into Vegetation Indexes were able to correlate to nitrate content with R² up to 0.65 in all experiments. This study demonstrates that focusing on just a few spectral regions facilitates the acquisition of suitable and robust information on nitrate content in spinach. Full article

Foliar application or minerals is a methodology to promote growth and/or yield and to protect plants against different kinds of stresses. Currently there is a great interest in evaluating the effect of nanoparticles for enhancing the effect of these treatments. This study was performed to evaluate and compare the effect of foliar application of zinc oxide (ZnO) and zinc oxide nanoparticles (ZnO-NPs) on the growth and yield of safflower under different irrigation regimes. Foliar applications of ZnO in all concentrations (4, 6, 8, 10, 12, and 14 g L⁻¹) led to an increase in biomass yield, number of capitula per plant, number of seeds per capitulum, and grain yield of plants compared with control plants. The maximum increase in the studied traits was obtained with a ZnO concentration of 6, 8, and 10 g L⁻¹. In a second round of experiments, we observed the effect of nanoparticles and found that spraying with ZnO and ZnO-NPs at a concentration of 10 g L⁻¹ may ameliorate the deleterious effects of water deficit. The results of the present study support the idea that foliar application of ZnO improves safflower yield, especially under drought stress, and showed that using of nanoparticles increases the efficiency of the application. Full article

Marigolds (Calendula officinalis L.) are valuable in ornamentation, human food, and other uses; to enhance productivity, plant growth regulators produce stimulatory effects, including salicylic acid (SA) and spermidine (SP), but there is a lack of scientific evidence about such effects in marigolds. The study assessed, under greenhouse conditions, changes in physico-chemical parameters, enzymatic activity, and bioactive compounds of marigold cvs. Hybrid and French marigolds were sprayed of SA (1 and 2 mM) and SP (2 and 3 mM) and compared to control (pure water). The SA at 2 mM improved leaf length (8.20 cm), flower height and diameter (5.32, 8.28 cm), flower fresh and dry weight (14.30, 1.5 g), and the maximum number of flower petals (55) in ‘Hybrid’. Similarly, 2 mM SA gave the maximum number of leaves (40.71) and stem thickness (5.76 mm) in ‘French’, but 3 mM SP promoted the maximum plant height in ‘Hybrid’. Superoxide dismutase, peroxidase, and catalase activities increased in ‘Hybrid’ with 2 mM SA; with this SA dose, ‘Hybrid’ had higher contents of total phenolic compounds (68.34 mg GAE g⁻¹), antioxidants (77%), carotenoids (110 mg 100 g⁻¹), and flavonoids (67.5 mg RE g⁻¹) than the control. The best dose for improving growth in both marigold varieties was 2 mM SA. Full article

Crop seeding depth is an important parameter in agrotechnologies, but how can seeding depth automatically be maintained in on-farm soil conditions with different textures, granulometric compositions, structural contents and penetration resistances? For this reason, an on-farm field experiment was conducted in the Panevėžys district (Lithuania) during 2020–2022. The field was divided into five zones (EZ1–EZ5) according to soil electrical conductivity. In addition, uniform and variable seeding depths were compared. The results of the investigations showed that soil electrical conductivity was highly correlated with sand (r = −0.867; p ≤ 0.010 > 0.001) and silt (r = 0.871; p ≤ 0.010 > 0.001) contents. The seeding method mainly did not have a significant effect on soil physical properties and winter wheat germination, development and productivity. Higher differences were observed among field zones. The winter wheat seeding depth varied from 27.74 to 33.12 mm between the two most different soil electrical conductivity zones. In zones with variable seeding depths, winter wheat seeds sprouted the most abundantly, and germination reached 99% (in EZ3 and EZ4). In EZ1, EZ2 and EZ4, the yields of grain were the highest and were significantly higher than that in the loamy sand of EZ5. The 1000-grain mass was not affected by any of the tested factors. The results suggest the need for further research in fields with a wider range of soil electrical conductivity. This can increase the variation in seeding depth and reveal interactions among the factors in more detail. Full article

Fusarium oxysporum f. sp. niveum (FON) causes watermelon wilt that is one of the major disease-causing yield losses of watermelon. Sustainable development of agriculture requires controlling watermelon wilt disease with good environmental performance. One important approach is to identify environmental-friendly compounds with inhibitory activity against FON. Thymol is a plant-derived compound that is safe for ecology. Little is known about the application of thymol in agriculture. In this study, we studied the inhibitory activity of thymol against FON by using morphological, physiological, and histochemical approaches. Thymol significantly inhibited colony diameter of FON in a dose-dependent manner, with EC₅₀ at 21 µg/mL. Thymol at 10, 21, and 35 µg/mL decreased the fresh weight of FON mycelia by 29.0%, 50.6%, and 69.5%, respectively. Microscopic observation revealed irregular damage and loss of shape of mycelia upon thymol exposure. Thymol induced the accumulation of superoxide radical in mycelial cells and accompanied increased activity of antioxidative enzymes (SOD, superoxide dismutase; CAT, catalase). Thymol induced membrane permeability was indicated by lipid peroxidation and electrolyte leakage (increased by 29–58%) in mycelial cells. These results suggested that thymol induced oxidative damage in mycelia, which may be one of the possible reasons for thymol-induced mycelial cell death observed with fluorescent detection. Thymol decreased the production of conidia and inhibited the germination of conidia. Thymol induced superoxide radical accumulation, lipid peroxidation, and cell death in conidia as well. All of these results revealed the inhibitory activity of thymol against FON, which may have resulted from the superoxide radical-induced oxidative injury in both conidia and mycelia of FON. Full article