Agronomy, Volume 14, Issue 6 (June 2024) – 195 articles

Rhododendron plants have ornamental, commercial, and medicinal value to people. Flavonoids are one of the components used in traditional remedies, and Rhododendron plants are found to be rich in flavonoids. Flavonoids can reduce the risk of human disease and participate in the regulation of antioxidant defense systems in response to heat stress. Rhododendron prefers cold climates, so the relatively high temperatures of cities affect the extraction of medicinal ingredients and limit the cultivation environment. Recent studies found that the exogenous application of calcium acts to alleviate heat stress in Rhododendron plants. This study explores the mechanism by which exogenous calcium alleviates heat stress and the role of flavonoids in regulating the antioxidative system in Rhododendron × pulchrum Sweet using combined transcriptomic and metabolomic methods. The activities of peroxidase, catalase and superoxide enzymes were found to increase in response to heat stress and external CaCl₂ in the leaves of R. × pulchrum. In total, 433 metabolic components and 370 DEGs were identified as being differentially expressed in response to heat stress and external calcium chloride (CaCl₂) in the leaves of R. × pulchrum. These results illustrate that heat stress induces oxidative stress and that external CaCl₂ can enhance the heat tolerance of Rhododendron. Flavonoid compounds are responsible for the antioxidant scavenging of reactive oxygen species in R. × pulchrum leaves exposed to heat stress and external calcium. Full article

Soybean is a crucial crop for sustainable agriculture development as it forms symbiotic relationships with rhizobia species. The effectiveness of inoculants in symbiosis, however, relies on the compatibility of the strain with a specific legume crop variety. This study assessed the symbiotic efficiency of eight Bradyrhizobium strains (SB-36, SB-37, SD-47, SD-50, SD-51, SD-53, SB-113, and SB-120) with five soybean varieties (Gishama, Awassa-95, Boshe, Hawassa-04, and Jalale) using sand culture. The experiment was arranged in a factorial, completely randomized design with three replicates. Data were collected on plant growth, and symbiotic effectiveness indices and subjected to statistical analysis using R software v4.3.1. The results revealed marked differences (p < 0.001) between the varieties, rhizobial strains, and their combined effects on all traits examined. The Jalale variety inoculated with Bradyrhizobium strains SB-113 and SD-53 produced the highest nodules per plant. When inoculated with SD-53, Awassa-95 demonstrated the highest relative symbiotic effectiveness [129.68%], closely followed by the Boshe variety [128.44%] when inoculated with the same strain. All strains exhibited high relative symbiotic effectiveness (>80%) with Awassa-95 and Boshe varieties. The highest absolute symbiotic effectiveness was observed in the Gishama variety inoculated with the SD-53 strain followed by Boshe and Awassa-95 varieties inoculated with this same strain. Notably, strain SD-53 demonstrated remarkable efficiency with the varieties Gishama, Boshe, and Awassa-95 based on both relative and absolute symbiotic effectiveness indices. Varieties inoculated with the SD-53 strain produced deeper green leaves. This study revealed the importance of Bradyrhizobium inoculation to improve soybean performance, for which the SD-53 strain performed best among the strains considered in the current experiment. Therefore, it is plausible to recommend inoculating soybeans with Bradyrhizobium strain SD-53 with prior field evaluation. Full article

Accurate positioning at the inter-row canopy can provide data support for precision variable-rate spraying. Therefore, there is an urgent need to design a reliable positioning method for the inter-row canopy of closed orchards (planted forests). In the study, the Extended Kalman Filter (EKF) fusion positioning method (method C) was first constructed by calibrating the IMU and encoder with errors. Meanwhile, 3D Light Detection and Ranging (LiDAR) observations were introduced to be fused into Method C. An EKF fusion positioning method (method D) based on 3D LiDAR corrected detection was designed. The method starts or closes method C by the presence or absence of the canopy. The vertically installed 3D LiDAR detected the canopy body center, providing the vehicle with inter-row vertical distance and heading. They were obtained through the distance between the center of the body and fixed row spacing. This can provide an accurate initial position for method C and correct the positioning trajectory. Finally, the positioning and canopy length measurement experiments were designed using a GPS positioning system. The results show that the method proposed in this study can significantly improve the accuracy of length measurement and positioning at the inter-row canopy, which does not significantly change with the distance traveled. In the orchard experiment, the average positioning deviations of the lateral and vertical distances at the inter-row canopy are 0.1 m and 0.2 m, respectively, with an average heading deviation of 6.75°, and the average relative error of canopy length measurement was 4.35%. The method can provide a simple and reliable inter-row positioning method for current remote-controlled and manned agricultural machinery when working in standardized 3D crops. This can modify the above-mentioned machinery to improve its automation level. Full article

Maize productivity in the central belt plays a significant role in the food security of China. With good adaptability and disease resistance, landrace germplasm is important for maize improvement. A total of 246 landrace accessions were collected from the maize belts in central China and genotyped with the SLAF-seq (Specific-Locus Amplified Fragment Sequencing) method, and 144,650 SNPs were obtained for each accession. The results showed that the landrace accessions could be divided into three major groups. In the cluster results, Group I included 64 accessions, which mainly belonged to the landrace of White horse teeth; Group II had 71 accessions, which mainly belonged to the lantern red landraces; the rest of the 116 accessions were clustered as Group III, including a variety of types landraces and seven indicator inbred lines. In the results of structure and multidimensional scaling, the accessions’ attribution differed with the clusters, the main reason for which is the attribution change in intermediate germplasms. Linkage disequilibrium decay distance was 0.98 kb, which was much lower than that of temperate and tropical maize inbred lines, indicated the much higher genetic diversity of landrace germplasms. The results can help us select suitable landrace germplasms and speed up the process of inbred line development and maize improvement. Full article

Bananas, a staple food globally and a key agricultural commodity, face a severe threat from the fungus Fusarium oxysporum f. sp. cubense (Foc), significantly impacting production. Genetic improvement to develop resistant cultivars stands out as a crucial strategy to mitigate this disease. This study focused on assessing and recommending enhanced diploid banana varieties for resistance against Foc subtropical race 4 (ST4) and Foc race 1 (R1). Twenty-four improved diploids developed by Embrapa, Brazil, underwent evaluation. Utilizing a scale for internal symptoms at 90 days after inoculation, genotypes were categorized from highly resistant to highly susceptible based on the internal symptom index. The diploid M53 exhibited high resistance to Foc R1 and resistance to Foc ST4, while only the diploid CNPMF 0534 demonstrated complete resistance to both R1 and ST4, with resistance to the latter likely associated with penetration, primarily due to the presence of callose. These findings provide valuable insights for banana and plantain breeding programs, offering selected diploids for crossbreeding with commercial cultivars to develop new, resistant genotypes against Foc. Full article

The quality of cotton fiber plays a pivotal role for both producers and processors, influencing the market value and end-product quality. Certain cotton fiber properties, such as length, strength, micronaire, and uniformity index, are crucial determinants of cotton quality. Despite its prominence as a cotton-producing region, the Aegean region in Türkiye lacks comprehensive studies examining the quality of its cotton fiber across different subregions and seasonal variations. This study aimed to address this gap by investigating the variations in cotton fiber quality across different years and subregions within the Aegean. This study involved the evaluation of a total of 368,686 individual fiber quality analyses conducted over seven years across three subregions within the Aegean in Türkiye. The fiber samples collected from Bergama, Söke, and Menemen underwent high-volume instrument (HVI) analysis to evaluate the variations in cotton fiber quality across years and subregions, considering the phenological stages of cotton and climate conditions. The findings highlighted significant variations in the fiber quality traits among subregions, with environmental factors such as temperature and humidity playing crucial roles. Higher average daily temperatures during the flowering stage to boll formation contributed to higher strength values, while limitations on fiber length were observed due to prevalent high temperatures. Additionally, variations in micronaire values were linked to temperature and humidity conditions during boll development stages. This study underscores the importance of comprehensively considering climatic factors to understand their impacts on cotton fiber quality and suggests further research into the cotton plant’s phenology and specific climate conditions for a more thorough understanding of environmental effects on fiber quality. Full article

Traditional deep learning models for fruit and vegetable classification are usually implemented via training on an unchanged dataset. However, changing fruit and vegetable categories is a very common occurrence in the context of real agricultural sales. When dealing with changes related to variety, deep learning models need to be retrained on the entire updated dataset. The retraining process is time-consuming and inefficient, and it may even cause the ‘catastrophic forgetting’ problem. In response to this challenge, the Adversarial Domain Adaptation Class Incremental Learning (ADA-CIL) method is introduced. This approach employs adversarial domain adaptation techniques combined with core-set selection strategies to effectively extract and integrate cross-domain features. We utilize the ResNet34 architecture as the backbone for feature extraction due to its deep residual learning framework, which is robust in handling the complexities of large and varied image datasets. It achieves a dynamic balance in learning between new and existing categories, significantly enhancing the model’s generalization capabilities and information retention efficiency. The FruVeg dataset, composed of three sub-datasets, includes over 120,000 color images, covering more than 100 different categories of fruits and vegetables collected from various domains and backgrounds. The experimental results on the FruVeg dataset show that the ADA-CIL method achieves an average accuracy of 96.30%, a forgetting rate of 2.96%, a cumulative accuracy of 96.26%, and a current accuracy of 98.60%. The ADA-CIL method improves the average accuracy by 1.65% and 1.82% compared to iCaRL and BiC, respectively, and it reduces the forgetting rate by 2.69% and 2.76%. These performance metrics demonstrate the ADA-CIL method’s impressive ability to handle incremental category and domain changes, highlighting its capability to effectively maintain the intra-class stability and exhibit exceptional adaptability in dynamic learning environments. Full article

As the third-largest maize-producing province in China and a typical arid and semi-arid region, quantitatively evaluating the carbon and nitrogen footprints of maize production and their dominant factors is of great significance in guiding the high-yield, low-carbon, and sustainable development of maize production in the Inner Mongolia Autonomous Region. This study quantitatively evaluated the interannual evolution characteristics of the carbon and nitrogen footprints in maize production and their dominant factors in Inner Mongolia from 2003 to 2022 based on statistical yearbook data and emission parameter models. The results showed that from 2003 to 2022, the maize planting area, yield, and total yield in Inner Mongolia all increased, with an average annual increase of 97 kg ha⁻¹ in yield and 1.23 × 10⁶ Mg in total yield. The carbon and nitrogen footprints of Inner Mongolia maize production over the past 20 years had overall decreasing trends, while the nitrogen fertilizer bias productivity, net ecosystem carbon balance, and sustainability index had increasing trends. Carbon footprint reduced by an average of 5.2 kg CO₂ eq Mg⁻¹ per year, and nitrogen footprint reduced by an average of 0.21 g N eq kg⁻¹ per year. Currently, the transportation and production of fertilizer and field application of N fertilizer are the main controlling factors of GHG emissions from maize production. NO₃⁻-N, NH₄⁺-N leaching, and NH₃ volatilization from field application of N fertilizer are the main sources of reactive N losses. The application of simplified processes, such as phased regulation of nitrogen and controlled-release fertilizers, as well as conservation tillage, have broad prospects for emission reduction in maize production in Inner Mongolia. Full article

In response to the significant challenge posed by the trade-off between the efficiency of separating potato soil and minimizing potato peel damage in the 4SW-170 potato excavator, this study focused on enhancing the design of the swing separation sieve. The objective was to develop a novel separation sieve comprising three distinct orders of sieve surfaces. Building upon this foundation, the EDEM-Adams coupled simulation method was employed to explore the fragmentation and separation attributes of potato–soil aggregates. This investigation aimed to elucidate the behavior of potato–soil aggregates within the operational scope of the novel swing separation sieve. Subsequently, the optimized parameters were validated through field tests. The findings indicate a direct correlation between the fracture ratio of the cohesive bond and the crank speed, illustrating an increase in the former with higher crank speeds. Conversely, an inverse relationship exists between the fracture ratio and the sieve inclination angle, demonstrating a decrease in the ratio as the sieve inclination increases. At a machine speed of 1.9 km/h, the fracture ratio of the cohesive bond attains its peak value. The force exerted on potatoes at their maximum point escalates with rising crank speed but diminishes with increasing machine speed. Conversely, the effect of sieve inclination on the peak force applied to the potatoes is deemed inconsequential. The most effective parameter configuration for the separation sieve comprises a crank speed of 180 revolutions per minute (r/min), a machine speed of 1.9 km per hour (km/h), and a sieve inclination of 14.4°. Field trials have confirmed that the parameter combination yielded a potato detection rate of 98.01% and a mere 0.68% rate of potato skin breakage, meeting the stipulated technical specifications of the potato harvester. Full article

Lettuce is an annual plant of the family Asteraceae. It is most often grown as a leaf vegetable, but sometimes for its stem and seeds, and its growth status and quality are evaluated based on its morphological phenotypic traits. However, traditional measurement methods are often labor-intensive and time-consuming due to manual measurements and may result in less accuracy. In this study, we proposed a new method utilizing RGB images and Mask R-Convolutional Neural Network (CNN) for estimating lettuce critical phenotypic traits. Leveraging publicly available datasets, we employed an improved Mask R-CNN model to perform a phenotypic analysis of lettuce images. This allowed us to estimate five phenotypic traits simultaneously, which include fresh weight, dry weight, plant height, canopy diameter, and leaf area. The enhanced Mask R-CNN model involved two key aspects: (1) replacing the backbone network from ResNet to RepVGG to enhance computational efficiency and performance; (2) adding phenotypic branches and constructing a multi-task regression model to achieve end-to-end estimation of lettuce phenotypic traits. Experimental results demonstrated that the present method achieved high accuracy and stable results in lettuce image segmentation, detection, and phenotypic estimation tasks, with APs for detection and segmentation being 0.8684 and 0.8803, respectively. Additionally, the R² values for the five phenotypic traits are 0.96, 0.9596, 0.9329, 0.9136, and 0.9592, with corresponding mean absolute percentage errors (MAPEs) of 0.1072, 0.1522, 0.0757, 0.0548, and 0.0899, respectively. This study presents a novel technical advancement based on digital knowledge for phenotypic analysis and evaluation of lettuce quality, which could lay the foundation for artificial intelligence expiation in fresh vegetable production. Full article

Intercropping is a vital cropping system that can create a conducive growth environment for crops and enhance land productivity. Tiger nuts (Cyperus esculentus L.) have high oil content and are adaptable to various soil types, making them a promising new oil crop with significant development potential. This study evaluated the plant height, leaf area, tiller numbers, biomass, land equivalent ratio (LER), and root morphological characteristics of tiger nuts. The agronomic traits and root distribution of tiger nuts and other crops were further investigated to achieve the goal of high yield for tiger nuts. Seven intercropping systems were implemented in the experiment: maize–tiger nut intercropping (MT), soybean–tiger nut intercropping (ST), cotton–tiger nut intercropping (CT), monoculture tiger nut (T), monoculture maize (M), monoculture soybean (S), and monoculture cotton (C). The results indicated that under different planting systems, the agronomic traits of tiger nuts in MT and ST modes were superior, with plant height and tiller numbers increasing by 7.6% to 11.6%. However, the plant height and Soil Plant Analysis Development (SPAD) values in CT mode were slightly lower than in T mode. Additionally, intercropping reduced the leaf area by 6.2% to 37.9%. Root development was more pronounced in intercropping modes, with the ST mode showing the most significant improvement, increasing the 0–20 cm root length density (RLD) by 12.2% to 45.7%. Therefore, each of the three intercropping modes demonstrated distinct advantages. The LER of the intercropping systems ranged from 1.10 to 1.24, enhancing land utilization, with tiger nuts being the dominant species. Compared to monoculture, the ST mode exhibited the best overall effect. Understanding the impact of different planting systems on tiger nuts provides valuable insights for developing tiger nut cultivation in Xinjiang. Full article

One important category of traditional remedies is medicinal plants, which are widely consumed by the population and often subjected to contamination. For the first time, the elemental composition of five wild medicinal plants traditionally consumed in the Republic North Ossetia—brook-mint (Mentha longifolia), oregano (Origanum vulgare), St. John’s wort (Hypеricum perforаtum), thyme (Thymus daghestanicus), and fireweed (Chamaenerion angustifolium)—and corresponding soil samples was determined. This investigation aimed to assess the degree of toxic element accumulation in plants and the possible toxic effect of the analyzed plants on human health. The analysis encompassed the quantification of 36 major and minor elements in soil samples, alongside the detection of 23 elements in plant samples using instrumental neutron activation analysis. According to contamination and enrichment factors, which were calculated in order to assess the level of soil pollution, elements such as As, Sb, Zn, and U in soil may originate from both geogenic and anthropogenic sources. In all plant samples, the most abundant major elements were K and Ca and their content ranged from 9870 to 49,500 mg·kg⁻¹ and 5400 to 20,000 mg·kg⁻¹, respectively, while among the microelements, Fe (54–2080 mg·kg⁻¹) and Mn (27.8–190 mg·kg⁻¹) can be highlighted as the most abundant. The transfer factor was calculated to estimate metal uptake from soil in plants. The highest values of the transfer factor were obtained for Mo, K, Ca, and Zn. The daily intake of metals and the health risk index were calculated to assess the safety of the collected plants. The health risk index was below the threshold for all plants suggesting a probable non-carcinogenic effect. Principal component analysis and linear discriminant analysis were used as classification techniques. The principal component analysis allowed us to define the main groups of elements and associate them with their sources of origin, while discriminant analysis enabled us to discriminate plant samples by species. Full article

Climate change might benefit water-stress-adapted weeds, further impairing their management. To evaluate the impact of soil moisture regimes on the growth and reproductive behaviour of ACCase-resistant and ACCase-susceptible phenotypes of sterile oat (Avena sterilis subsp. ludoviciana (Durieu) Nyman), a greenhouse experiment was carried out in 2020 and 2021. The factors were soil moisture regimes (100% field capacity (FC) as well-watered, 75% FC, 50% FC, and 25% FC) and ACCase-resistant and ACCase-susceptible phenotypes of sterile oat. Increased drought stress conditions reduced the number of tillers per plant by 34, 55, and 83% and the number of seeds per plant by 36, 61, and 89% in the 75% FC, 50% FC, and 25% FC conditions, respectively, compared to the well-watered treatment. Notably, both phenotypes reacted similarly to water stress, with no interactions between the two factors. Regardless of water stress, the resistant phenotypes produced fewer seeds per plant, indicating fitness costs. However, due to their high plasticity, both phenotypes will still produce seeds even when facing severe water stress conditions. Thus, sterile oat is expected to continue infesting crop fields in the near future, but with ACCase-resistant phenotypes being less successful than susceptible ones in the absence of herbicide application. Full article

The TALE gene family plays a crucial role in regulating growth, development, and abiotic stress responses in plants. However, limited studies have been conducted on the functions of the ZmTALE gene family in maize under drought stress. This study identified 40 members of the ZmTALE family within the maize genome through Blast comparisons, distributed unevenly across the first nine chromosomes. Intraspecific collinearity analysis revealed 13 linked pairs. By constructing a phylogenetic tree with Arabidopsis AtTALE members as references, maize members were divided into two subfamilies, KNOX and BEL1-Like, with KNOX further divided into three branches (KNOX Class I, KNOX Class II, and KNOX Class III). The gene structure and motifs of ZmTALE genes within the same subfamily or branch showed similarities, as did their encoded proteins, which possess similar motifs and conserved domains. Analysis of the physicochemical properties of the ZmTALE proteins revealed that the proteins encoded by this family are stable. Expression analysis of ZmTALE genes in maize demonstrated their varied roles in development and drought stress regulation, confirmed through qRT-PCR. The identification, characterization, and expression analysis of ZmTALE genes provide a reference for future gene function research and aid in the genetic enhancement of maize to withstand drought stress. Full article

The application of potassium fertilizer application and straw return are effective agronomic measures for increasing crop productivity; however, information on how straw return—when substituting potassium fertilizer—affects crop yield, efficiency, and quality in dryland remains limited. In this study, an experiment on a dryland summer maize and winter wheat rotation system was initiated in 2007. This study included four treatments: CK (no fertilizer and no straw return), NP (nitrogen and phosphorus fertilizer application without straw return), NPK (nitrogen, phosphorus, and potassium fertilizer application without straw return), and NPS (NP treatment with straw return, substituting potassium fertilizer as used in the NPK treatment). These treatments were employed to assess grain yield and fertilizer agronomic efficiency in 2015–2020. Additionally, we evaluated the content of nitrogen (N), phosphorus (P), and potassium (K), as well as the protein content and protein yield in maize and wheat grains and the protein components in wheat grains in 2019–2020. The results showed that compared to the CK treatment, NP, NPK, and NPS treatments not only significantly increased the yield, protein yield, and fertilizer agronomic efficiency in both maize and wheat but also increased the content of protein and protein components in wheat grains. Compared to the NP treatment, the NPK treatment significantly increased the contents of N, K, globulin, and gluten in wheat grains by 5.11%, 21.59%, 10.06%, and 15.14%. Compared to NPK treatment, NPS treatment significantly increased the average yield of summer maize by 21.33% and 20.91%, respectively, as well as the annual yield by 9.99% and 13.59%, the N fertilizer agronomic efficiency of summer maize by 132.47%, and the annual N and P fertilizer agronomic efficiency by 42.83% and 64.36%, over the five-year period. The NPS treatment also significantly increased the summer maize protein yield and annual protein yield by 10.43% and 23.08%, as well as the content of protein components, the protein content, and P content in wheat grains by 4.93–13.58%, 7.81%, and 28.89%, respectively. In conclusion, NPS treatment can not only enhance crop yield, protein yield, and fertilizer agronomic efficiency in summer maize annually but also has the advantage of promoting wheat quality. NPS is an efficient strategy to improve crop yield, efficiency, and quality in a dryland maize–wheat rotation system. Full article

Overground rock is a prominent feature of rocky desertification landscape in karst farmland; however, people often pay attention to their adverse effects, leaving their positive effects on ecohydrological processes and plant growth as rarely studied and utilized. In this study, the effects of overground rock film mulching (ORFM) on soil water flow behavior, soil water content and temporal and spatial heterogeneity were investigated through a dye tracer test and soil moisture measurement. Moreover, the effects of this technology on the root characteristics of crops (maize and broad bean) were analyzed. The results showed that ORFM treatment significantly increased soil water content and its spatio-temporal heterogeneity by preventing preferential flow at the rock–soil interface. It suggested that this practice can provide a more favorable soil moisture environment for crop growth, which was confirmed by the differences in root characteristics of crops (maize and broad bean) under different treatments in this study. It was found that ORFM treatment reduced the root radial extent of crops but increased the root biomass and root bifurcation rate, which are widely considered to be key factors in improving the efficiency of fine root absorption. Therefore, we believe that ORFM has great potential to improve the effective use of soil water and agricultural water management in karst areas, which is essential for sustainable agricultural development in the region. Full article

We used 256 apple germplasm resources for a thorough examination of the genetic diversity associated with 26 phenotypic traits (i.e., genetic diversity analysis, cluster analysis, correlation analysis, principal component analysis, and membership function). The average coefficient of variation for 12 morphological traits was 66.39% (21.10–201.5%). The coefficient of variation was highest and lowest for the fruit arris and the width of the eye basin, respectively. Additionally, the diversity index ranged from 0.54 to 1.33. Moreover, the coefficient of variation for 14 numerical traits varied from 5.37% to 50%. The titratable acid content had the highest coefficient of variation, with a diversity index ranging from 2.01 to 2.08 (average of 2.045). A cluster analysis categorized 256 germplasms into four groups, among which Group I included germplasms with large fruits and the best comprehensive performance. Of the top 10 principal components revealed by the principal component analysis, principal component 1 was mainly related to fruit size and flavor. The top 10 germplasms were selected on the basis of comprehensive scores using the membership function method. Furthermore, a stepwise regression analysis identified 15 key traits for identifying apple germplasms, including the vegetative growth day, fruit weight, and the firmness of the fruit without skin. These results can serve as the foundation for future analyses of the phenotypic diversity of apple germplasms, while also providing a theoretical basis for screening, characterizing, and further improving excellent apple germplasms. Full article

Conservation, characterization and exploitation of agrobiodiversity are key factors to guarantee food security and face future challenges such as climate changes. These issues are the subject of a series of international agreements, such as the Convention of Biological Diversity, with its Nagoya Protocol, and the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA) adopted in 2001 and entered into force in 2004. Italy ratified the Treaty in 2004 and instituted a long-lasting program, RGV-FAO, to implement it. CREA is one of the three organizations involved in the RGV-FAO Program, together with the National Research Council (CNR) and Reti Semi Rurali. CREA maintains a total of 40,186 accessions including cereals, vegetables, fruits, forages, industrial crops, forest and woody crops, medicinal and aromatic plants, and their wild relatives. Accessions are conserved using different ex situ conservation systems (seeds, in vivo plants, vegetative organs and in vitro plantlets), and characterized using genetic, morpho-phenological and/or biochemical methods. Herein, we will present the CREA long-lasting program RGV-FAO with some examples of the use of plant genetic resources in breeding programs, including molecular approaches. Some critical issues related to access and benefit sharing in PGRFA, such as the Nagoya Protocol and the Digital Sequence Information, will be discussed, highlighting their potential impact on food security and on the advancement of knowledge. Full article

Shaping the canopy architecture and delaying leaf senescence in maize are pivotal strategies for extending the crop’s photosynthetic period and improving yield. The application of plant growth regulators (PGRs) is a critical cultivation measure, with the timing of application being of paramount importance. To explore the effects of PGR application time on maize canopy structure, leaf senescence characteristics and yield, a comparative two-year field study was undertaken during the 2019–2020 growing seasons at the Gongzhuling Experimental Station of the Jilin Academy of Agricultural Sciences, utilizing a PGR containing ethephon as the active ingredient. The experiment was structured with two plant densities of 60,000 and 90,000 plants ha⁻¹, and three distinct PGR application protocols: T10 (application of PGR at the 10th leaf stage), T15 (application at the 15th leaf stage), and CK (control group sprayed with water). The result indicated that the yield increased by 5.62% following T15 treatment compared to the CK under high density (90,000 plants ha⁻¹). Furthermore, the kernel per ear and the 1000-kernel weight increased by 3.93% and 5.62% respectively, while the abortion rate decreased. Correlation analysis showed that yield and yield components were correlated with plant morphology, physiology, and aging characteristics under 90,000 plants ha⁻¹. Pollen density was also positively correlated with the top leaf area and the top leaf angle (p < 0.01). Furthermore, relative green leaf area at maturity (RGLAM) showed positive correlations with chlorophyll b, superoxide dismutase activity (SOD), peroxidase activity (POD), catalase activity (CAT), and soluble protein content (p < 0.01), while displaying a negative correlation with malondialdehyde content (MDA) (p < 0.01). Spraying plant growth regulators at the 15-leaf stage under high density can effectively enhance the top canopy structure of the maize and reduce the upper leaf area and angle, increase pollen density, and boost the number of grains. Furthermore, it delayed the senescence of leaves, prolonged the functional period of the leaves, increased kernel weight, optimized light resource utilization, and ultimately enhanced the maize yield. Full article

Intercropping, a well-established agroecological technique designed to bolster ecological stability, has been shown to have a significant impact on soil health. However, the specific effects of tea/Trachelospermum jasminoides intercropping on the physicochemical properties and functional microbial community structure in practical cultivation have not been thoroughly investigated. In this study, we utilized high-throughput sequencing technology on the 16S/ITS rDNA genes to assess the impact of tea intercropping with T. jasminoides on the composition, diversity, and potential functions of the soil microbial community in tea gardens. The results indicated that the tea/T. jasminoides intercropping system significantly increased pH levels, soil organic matter, available nitrogen, phosphorus, potassium, and enzyme activity, ultimately augmenting soil nutrient levels. Furthermore, an in-depth analysis of the bacterial co-occurrence network and topological structure portrayed a more intricate and interconnected soil bacterial community in tea gardens. Remarkably, the abundance of beneficial genera, including Burkholderia, Mesorhizobium, Penicillium, and Trichoderma, underwent a substantial increase, whereas the relative abundance of pathogenic fungi such as Aspergillus, Fusarium, and Curvularia experienced a marked decline. Functional predictions also indicated a notable enhancement in the abundance of microorganisms associated with nitrogen and carbon cycling processes. In summary, the intercropping of tea and T. jasminoides holds the potential to enrich soil nutrient content, reshape the microbial community structure, bolster the abundance of functional microorganisms, and mitigate the prevalence of pathogenic fungi. Consequently, this intercropping system offers a promising solution for sustainable tea garden management, overcoming the limitations of traditional cultivation methods and providing valuable insights for sustainable agriculture practices. Full article

Pesticides play a crucial role in agricultural production by preventing diseases and pests and ensuring food yield. However, the irrational use of pesticides can lead to numerous issues that compromise crop quality and counteract the original intentions of their application. Therefore, it is necessary to identify more effective methods to counteract pesticide stress. Here we review the impacts of herbicides, insecticides, and fungicides on plants and the measures taken to reduce pesticide residues on plants. We have found that despite the substantial differences in the mechanisms of action of the aforementioned three types of pesticides, the adverse effects they inflict on plants are similar, and at certain dosages, they can severely constrain plant growth and disrupt physiological functions. Also, most current research on using exogenous growth regulators to alleviate pesticide stress still focuses on photosynthesis, the antioxidant system, three-stage detoxification, and secondary metabolites, neglecting the search for genes that respond to pesticide stress. We believe that by combining biological protection with post-harvest treatment techniques and exploring potential genes that are responsive to pesticide stress, a better strategy for dealing with pesticide stress can be found, thereby promoting sustainable agricultural development. Full article

This study was designed to investigate the relationship between the caloric value and salt tolerance of two varieties of Miscanthus sacchariflorus (Amur silvergrass: M127 and M022). The salt tolerance capacity, photosynthetic characteristics, Na⁺ and K⁺ uptake by the roots and aboveground parts, and caloric value of different parts of the aboveground parts were obtained under hydroponic conditions. The results showed that M022 was more tolerant to salt stress than M127 and the former had a higher photosynthetic efficiency as well as a lower aboveground Na⁺ accumulation, K⁺ efflux, and larger K⁺/Na⁺ ratio. The calorific values of stems, spear leaves, aging leaves, and functional leaves of the two varieties showed a decreasing trend with increasing NaCl concentration. At 270 mM NaCl, the calorific values of the stems, aging leaves, functional leaves, and spear leaves was reduced by 18.10%, 46.73%, 26.11%, and 18.35% for M022 and 41.99%, 39.41%, 34.82%, and 45.09% for M127 compared to the controls, respectively. We observed that the aging leaves of M022 had a faster decline rate in calorific value than those of M127, indicating that the aging leaves of M022 preferentially isolated the harmful Na⁺ ion, reduced its accumulation in other parts, and increased the K⁺/Na⁺ ratio in the corresponding parts, thus inhibiting the decrease in calorific value. Following this result, it can be inferred that M022 inhibited the decline in calorific values during stress by efficiently compartmentalizing the distribution of Na⁺ and K⁺. Our results provide a theoretical basis and technical support for the efficient cultivation of salt-tolerant energy plants in saline–alkaline soil. Full article

Stevia rebaudiana Bertoni originated in South America, but has gained popularity due to the concentration of sweet steviol glycosides present in its leaves. Stevia is also currently grown on other continents in many countries characterised with warm climate. This research aimed to determine whether different irrigation practices might have a significant influence on the yield and composition of the leaves of stevia plants grown in Poland, in cooler climate than native regions for stevia plants. Stevia plants were grown with four different irrigation regimes: irrigation twice a week, irrigation once a week, irrigation only during times of the drought and not irrigated at all. It was determined that different irrigation regimes have substantial effects on the yield, biometric characteristics and chemical composition of stevia leaves, but none of the irrigation regimes were clearly supreme to the others. Yield of stevia plants that were irrigated once a week or only during the drought times was the highest (2.42–2.58 kg per square meter). Stevia plants that were not irrigated were characterised with the lowest height and lateral width (47.61 and 25.35 cm). Leaves of un-irrigated stevia contained the greatest dry mass content (30.47%) and highest concentration of phenolic compounds (337.88 mg per 100 g of fresh stevia leaves). Stevia plants that were irrigated once or twice a week were characterised with a lower concentration of chlorophylls or carotenoids at the time of the harvest (1.20–1.24 and 2.54–2.58 mg per gram of fresh stevia leaves), but stevia plants that were not irrigated contained a greater amount of chlorophyll and carotenoids (1.58 and 3.17 mg per gram of fresh stevia leaves). Full article

An important source of greenhouse gases in Brazil is the nitrous oxide (N₂O) emission from pasture, and microorganisms play an important role in nitrogen transformations in the soil. This study aimed to evaluate N₂O emission and NH₃ volatilization from bovine excreta in pasture in an integrated crop–livestock system (ICL) in the Brazilian Cerrado. Three treatments (urine, dung and control) were performed in two pastures (Area 1—three-year pasture of Urochloa ruziziensis and Area 2—one-year pasture of Urochloa brizantha cv. Piatã), with two application times of the excreta (dry and rainy season), during two successive years of application. Compared to the control, the excreta deposition on ICL increased soil N₂O and NH₃ fluxes. In the dry season, N₂O fluxes were associated with higher ammonium (NH₄⁺) availability. In the rainy season, these fluxes were related to NO₃⁻ availability and water-filled pore space (WFPS). In both areas, NH₃ volatilization was higher after urine than dung application, especially in the dry season. The highest N₂O emission factors were obtained for urine (0.32%), the rainy season (0.36%), and older pasture (Area 1: 0.24%). All these values were below the mean IPCC default values (0.77%). These results indicate that N₂O emissions in pasture should be evaluated in regional conditions. Full article

Miscanthus spp. has been regarded as a promising industrial plant for the sustainable production of bio-based materials. To assess its potential for microcrystalline cellulose (MCC) and cellulose nanocrystals (CNCs) production, 50 representative clones of M. sinensis and M. floridulus were selected from a nationwide collection showcasing the extensive diversity of germplasm resources. Descriptive analysis indicates that the dry biomass weight of M. floridulus is advantageous whereas M. sinensis demonstrates higher MCC and CNCs yields as well as a smaller CNCs particle size. Correlation analyses indicated that MCC yield is solely influenced by the cellulose content whereas the yield of CNCs is affected by both the cellulose content and CrI. Comparative analyses of the chemical composition, physical features (degree of polymerization, crystalline index, particle size distribution and zeta potential), and scanning electron microscopy indicated that the MCC and CNCs extracted from M. sinensis and M. floridulus exhibited remarkable stability and quality. Additionally, the CNCs derived from M. sinensis and M. floridulus exhibited a distinctive ball-shaped structure. Notably, machine learning has demonstrated its efficacy and effectiveness in the high-throughput screening of large populations of Miscanthus spp. for predicting the yield of MCC and CNCs. Our results have also laid the theoretical foundation for the exploration, cultivation, and genetic breeding of M. sinensis and M. floridulus germplasm resources with the purpose of MCC and CNCs preparation. Full article

Excessive application of nitrogen fertilizer in the swollen-stem mustard cultivation leads to a series of environmental and quality issues. It was reported that reducing nitrogen fertilizer with biochar could increase crop yield and reduce environmental risks. However, the effect of nitrogen reduction combined with biochar application on the flavor substances was rarely reported. Thus, two genetic stem mustard varieties (Yx: Yong’an xiaoye and Fz: Fuza No. 2), and four N treatments (control: 0 N kg/ha with biochar; N150: 150 N kg/ha with biochar, N300: 300 N kg/ha with biochar, and N450: 450 N kg/ha) were chosen to study the effects of nitrogen reduction combined with biochar on the flavor substance content of mustard stem, and N balance. The results showed that the residual soil inorganic N in N300 was lower by 37% than that in N450 (156.5 kg/ha) in Fz mustard soil, and lower by 33% in N150 than in N450 (163.1 kg/ha) in Yx mustard. The highest biomass of stem mustard tumors of Fz (35.4 × 10³ kg/ha) and Yx (35.7 × 10³ kg/ha) was in N300. The content of umami amino acids, sweet amino acids, and bitter amino acids of Yx and Fz stem was the highest in N450, and N300, respectively. After comprehensive consideration, the Fz was recommended to be planted in the Three Gorges Reservoir Area with N300. Full article

Saline-sodic stress induces iron deficiency in rice, reduces leaf photosynthetic performance, and inhibits yield enhancement. In this study, we investigated the effects of exogenous Fe on the photosynthetic performance and transcriptomics of two different tolerant rice cultivars CB9 (Changbai9: saline tolerant cultivar) and TH899 (Tonghe899: saline sensitive cultivar) with 4-week-old Fe-deficient rice seedlings under saline stress, Fe deficiency stress, and both co-stresses. The results showed that under saline and alkaline stress, spraying exogenous iron favored the growth of the two cultivars of rice, with a 32.68% and 39.82 increase in fresh weight, a 2.20-fold and 2.16-fold increase in pigment, respectively, and an 80.28% and 100.00% increase in net photosynthetic rate, respectively, as compared with the iron-deficiency treatment. Transcriptome analysis showed that we found a higher number of differentially expressed genes (7785 differentially expressed genes) in response to exogenous Fe spraying in the soda-salt sensitive variety TH899. The differentially expressed genes that are common to the two cultivars are primarily enriched in metabolic pathways, including plant hormone signal transduction (map04075) and phenylpropanoid biosynthesis (map00940). Specifically, among these genes, 14 are differentially expressed in the carotenoid biosynthetic metabolic pathway. The differentially expressed genes specific to the salinity-tolerant variety CB9 were mainly enriched in the metabolic pathways of glyoxylate and dicarboxylic acid methyl metabolism (map00630), and carbon fixation in photosynthetic organisms (map00710), among which 20 genes were significantly expressed in the pathway for carbon fixation in photosynthetic organisms (map00710). The research results offer specific theoretical support for enhancing the salt tolerance of rice. Full article

Very little is known about the preservation and storage of fresh medicinal and aromatic plants (MAPs) and/or herbs. As with many leafy vegetables, i.e., lettuce, fresh spearmint is a very perishable product throughout the production line and requires special handling/processing. The current study aimed to examine the antibacterial activity of selected MAPs (Origanum dubium, Salvia fruticosa and Sideritis cypria) grown in Cyprus towards foodborne pathogens. Then, the most effective MAPs’ essential oil (EO) and hydrosol (at different doses; combination of concentration and time of dipping submerge) were tested to preserve fresh spearmint quality and safety. The results showed that O. dubium EO and hydrosol presented great in vitro antibacterial activity against four foodborne pathogens and those products were further selected for application on fresh spearmint. During sensory evaluation, it was observed that higher O. dubium EO concentrations and longer time of application resulted into a less marketable product (less acceptable with less spearmint-like aroma), while hydrosol resulted in a more marketable product even at high doses. In general, EO and hydrosol applications increased spearmint’s antioxidants (including polyphenols, flavonoids, and ascorbic acid), resulting in a product of increased nutritional value. The bacterial populations of Salmonella enterica and Listeria monocytogenes inoculated on fresh spearmint were decreased with the EO and hydrosol application doses applied, and their effects were evident even after six days of storage at 4 °C. From the findings of this study, it can be concluded that O. dubium EO and hydrosol could be a potential sanitation method for fresh spearmint preservation. Full article