Improve Crop Productivity Research Articles

Variation in over-yielding of pulse-oilseed intercrops

ContextIntercropping is used to improve crop productivity and sustainability. However, total and partial yields of intercrops vary widely due to both intercropping system and environment. Understanding the factors controlling this variability would be of value for crop producers deciding whether and how to adopt intercropping. ObjectiveOur objective was to determine the dominant factors controlling total and partial yields of pulse-oilseed intercrops in a semiarid region. MethodWe conducted a field study for three years in southern Alberta under both dryland and irrigated conditions with lentil (Lens culinaris) and pea (Pisum sativum) intercropped with canola (Brassica napus) or mustard (Sinapis alba). Oilseed plant density and N fertility was varied and competition for soil and fertilizer N was measured using 15N. ResultsCrop productivity expressed using the Land Equivalent Ratio (LER) ranged from 0.98 to 1.75, similar to the range reported in the literature. High LER occurred when monocrop oilseed yields were strongly limited by N and increased when the oilseed crop was more competitive for fertilizer and soil N. In 2018, canola was about 4- to 6-fold more competitive for fertilizer N than pea or lentil and LER was high when N was limiting. In 2019 and 2020, mustard was about 3-fold more competitive than lentil but no more competitive than pea and LER was only higher when mustard was intercropped with lentil and N was limiting. Modifying oilseed plant density primarily impacted partial yields, not LER. Application of N fertilizer at 50 kg ha-1 reduced LER by 12%, whether applied at seeding or at five weeks. Over-yielding in this study was largely controlled by complementary N use, with variation in total and partial yields largely accounted for by the deficit in N supply for the oilseed crop, relative crop competiveness for soil N, and plant density. ImplicationsThe primary benefit of intercropping pulse and oilseed crops is sustained crop productivity with reduced N fertilizer inputs or under variable N sufficiency. Reliable prediction of total and partial yields should be feasible and allow crop producers to evaluate whether and how to incorporate intercrops into crop rotations. Studies on intercrops of legumes with non-legumes should include an N-sufficient non-legume control and benefit from the use of 15N to measure competition for soil N.

The impact of compost and expanded perlite on soil physical properties and water productivity under different irrigation practices

Finding an appropriate field management strategy for improving crop and water production becomes an imperious necessity because of the irrigation water deficiency in most of the agricultural fields in Iraq. Studying the response of soil properties to the applied soil amendments represents one of the critical parameters in agricultural field management for improving crop production and water use efficiency of Iraqi strategic crops. The effect of soil amendments (compost = 7.5 t/ha and perlite/0.1% Polyvinyl alcohol = 0.25 t/ha) on the water use efficiency and crop production under three levels of water depletion (30, 50, and 70%) of the available soil water was examined for wheat and barley crops. The study was applied under the sprinkler irrigation system. The experimental design was RCBD within 6 treatments and 3 replications for each wheat and barley. The results show that the soil amendments of expanded perlite and compost exhibit an improvement in the soil properties of soil bulk density and soil water content. Soil amendments, especially, the expanded perlite improved the crop yield and water use efficiency under all irrigation levels. The effect of expanded perlite shows the maximum effect on barley production under the 50% irrigation level with 3500 kg/ha. The irrigation level of 70% could be a worth-able management strategy if it is associated with the soil amendments of compost and expanded perlite. As a result, the effectiveness of expanded perlite increased with the increase in the drought of Iraqi soil.

Rice farmers’ knowledge, attitudes and practices towards mosquitoes in irrigation schemes in Côte d’Ivoire: a qualitative study

BackgroundIrrigated rice cultivation in sub-Saharan Africa not only brings more malaria vectors to nearby communities, but also greater malaria risk. To aid the implementation of mosquito control in rice-growing communities, it is necessary to understand how farmers understand, view and manage their responsibility in mosquito generation and whether they are interested in coordinating to minimize it.MethodsQualitative methods (observation grids, semi-structured in-depth interviews and focus group discussions) were used to reveal the perceptions of mosquitoes and their control in two irrigated rice farming communities in central Côte d’Ivoire near the M’bé and Lokapli irrigation schemes.ResultsAll rice farmers viewed mosquitoes as severe nuisances, and most acknowledged that they caused djèkouadjo (malaria) and were less numerous during harmattan (dry season). Many study participants believed that mosquitoes originated from grasses and stagnant water around villages. Only those living closer in proximity (~ 1 km) to the paddies believed that mosquitoes came from the bas-fonds (irrigated lowlands). However, they did not associate mosquito production with rice cultivation. Some farmers believed that there were more mosquitoes in recent years than historically because of the dam construction, but remarked on the importance of the dam (and bas-fonds) for their livelihood. Many farmers were not convinced that mosquito control could occur at farm-level.ConclusionsTo enhance accountability amongst rice farmers, there is a need for greater awareness on the rice-mosquito link, and emphasis that the link does not imply a trade-off between food production and health. Training should not only be directed towards farming communities, but also agricultural and health extension workers. Future riceland mosquito control methods must focus on improving crop productivity and address collective action problems that may occur.

Designing a synthetic microbial community through genome metabolic modeling to enhance plant–microbe interaction

BackgroundManipulating the rhizosphere microbial community through beneficial microorganism inoculation has gained interest in improving crop productivity and stress resistance. Synthetic microbial communities, known as SynComs, mimic natural microbial compositions while reducing the number of components. However, achieving this goal requires a comprehensive understanding of natural microbial communities and carefully selecting compatible microorganisms with colonization traits, which still pose challenges. In this study, we employed multi-genome metabolic modeling of 270 previously described metagenome-assembled genomes from Campos rupestres to design a synthetic microbial community to improve the yield of important crop plants.ResultsWe used a targeted approach to select a minimal community (MinCom) encompassing essential compounds for microbial metabolism and compounds relevant to plant interactions. This resulted in a reduction of the initial community size by approximately 4.5-fold. Notably, the MinCom retained crucial genes associated with essential plant growth-promoting traits, such as iron acquisition, exopolysaccharide production, potassium solubilization, nitrogen fixation, GABA production, and IAA-related tryptophan metabolism. Furthermore, our in-silico selection for the SymComs, based on a comprehensive understanding of microbe-microbe-plant interactions, yielded a set of six hub species that displayed notable taxonomic novelty, including members of the Eremiobacterota and Verrucomicrobiota phyla.ConclusionOverall, the study contributes to the growing body of research on synthetic microbial communities and their potential to enhance agricultural practices. The insights gained from our in-silico approach and the selection of hub species pave the way for further investigations into the development of tailored microbial communities that can optimize crop productivity and improve stress resilience in agricultural systems.

Evaluation of the feasibility of using inorganic and organic acids for the extraction of amino acids from high-protein material (mealworm larvae) by chemical hydrolysis

High-protein mealworm larvae (Tenebrio molitor) were treated with organic and inorganic acids in order to check the feasibility of applying acid hydrolyzates derived from them. Hydrolysis was optimized for the highest content of amino acids that have beneficial effects on plant development. The response surface method served the purpose of selecting optimal process conditions for such media as phosphoric acid, citric acid, acetic acid and mixtures of phosphoric and citric acids. The elemental composition of the best formulations and their amino acid profile was determined. Plant tests on cucumber (germination and pot tests) revealed the beneficial effect of the hydrolyzates on plant biometric parameters. By offering valuable insights into the relationship between fertilizer treatments and plant growth, our study contributes to developing sustainable agricultural practices and improved crop productivity.

Evaluation of nano-nitrogen fertilizers and other nitrogen sources on the performance of Guinea grass plants grown in newly reclaimed soil under water deficiency

Water deficiency and chemical fertilizers' pollution are two of many factors causing imbalance in the ecosystem rhythm, which reflects on farm livestock quality and quantity, particularly in arid and semi-arid regions. Limited research is available on the use of different sources of nitrogen fertilizers on pasture crops; hence, an open field research experiment was carried out in newly reclaimed soil to investigate the effect of different sources of nitrogen fertilizers on maximizing protein level and production of Guinea grass (Panicum maximum Jacq.) plant under water deficiency. Present data from two successive seasons revealed that: plants received nitrogen in the form of nano particles recorded significant increases in yield, morphological parameters, leaf anatomy, and chemical composition (macro and micro nutrients, total carbohydrates, plant pigments and crude protein) over control (plants that received the recommended dose of NPK fertilizers) in both growing seasons. In addition, endogenous hormones; gibberellins (GA3) and abscisic acid (ABA) beside enzymes; superoxide dismutase (SOD) and peroxidase (POD) had been affected by different treatments. The lowest amounts of cellulose, hemicellulose and lignin were resulted from nitrogen nano particles treatment, while the rates of leaf photosynthesis, stomatal conductance, intercellular CO2 concentration, and water use efficiency were enhanced also by nitrogen nano particles treatment application. The present findings suggested that increasing crude protein level of Guinea grass plant grown in newly reclaimed soil by addition of the mentioned nanoparticles could be a promising approach to improve crop productivity under water deficiency and reduce environmental pollution.

Subtle Responses of Soil Bacterial Communities to Corn-Soybean-Wheat Rotation

Crop rotational diversity can improve crop productivity and soil health, and boost soil microbial diversity. This research hypothesized that a 3-year rotation of corn-soybean-wheat (CSW), compared with a 2-year corn-soybean (CS) rotation, would result in a more diverse and more complex soil bacterial community, together with a greater abundance of beneficial bacteria. This was evaluated in a replicated experiment established in 2013 at two locations in Ohio (United States). The soil bacterial communities under soybean were compared between CS and CSW at both studied sites in 2018 and 2019, through 16S ribosomal DNA amplicon metabarcoding. Experimental site was the main driver of bacterial richness and evenness. Significant effects on bacterial community composition were observed in response to the interaction between site, rotational sequence, and year of study. Eight bacterial amplicon sequence variants were identified within all CSW treatments and were not present in CS. Several taxa were differentially abundant between rotation treatments, including the genera Ralstonia being more abundant in CS. Co-occurrence networks, including hub taxa, were generally different between rotation treatments and year, with more structure observed in CSW networks for one of the studied sites. Few bacterial genera were consistently identified as hubs across all networks, including an unidentified member of order Acidobacteriales, while other hubs were unique for CSW networks, including members of the family Gemmatimonadaceae. Finally, the composition of the bacterial communities at the northwestern site positively correlated with plant biomass and active carbon, whereas more recalcitrant pools (total carbon and organic water) correlated with the bacterial communities at the western site.

Boron seed coating combined with seed inoculation with boron tolerant bacteria (Bacillus sp. MN-54) and maize stalk biochar improved growth and productivity of maize (Zea mays L.) on saline soil

Salinity exerts significant negative impacts on growth and productivity of crop plants and numerous management practices are used to improve crop performance under saline environments. Micronutrients, plant growth promoting bacteria and biochar are known to improve crop productivity under stressful environments. Maize (Zea mays L.) is an important cereal crop and its productivity is adversely impacted by salinity. Although boron (B) application, seed inoculation with boron-tolerant bacteria (BTB) and biochar are known to improve maize growth under stressful environments, there is less information on their combined impact in enhancing maize productivity on saline soils. This study investigated the impact of B seed coating combined with seed inoculation with BTB + biochar on maize productivity under saline soil. Four B seed coating levels [0.0 (no seed coating), 1.0, 1.5, 2.0 g B kg−1 seed], and individual or combined application of 5 % (w/w) maize stalk biochar, and seed inoculation with Bacillus sp. MN-54 BTB were included in the study. Different growth and yield attributes and grain quality were significantly improved by seed coating with 1.5 B kg−1 seed coupled with biochar + BTB. Seed coating with 1.5 B kg−1 seed combined with biochar + BTB improved stomatal conductance by 32 %, photosynthetic rate by 15 %, and transpiration ratio by 52 % compared to seed coating (0 B kg−1 seed) combined with biochar only. Similarly, the highest plant height (189 cm), number of grain rows cob−1 (15.5), grain yield (54.9 g plant−1), biological yield (95.5 g plant−1), and harvest index (57.6 %) were noted for B seed coating (1.5 g B kg−1 seed) combined with biochar + BTB inoculation. The same treatment resulted in the highest grain protein and B contents. It is concluded that B seed coating at 1.5 g B kg−1 seed combined with biochar + BTB inoculation could significantly improve yield and quality of maize crop on saline soils. However, further field experiments investigating the underlying mechanisms are needed to reach concrete conclusions and large-scale recommendations.

Community Structure and Diversity of Endophytic Bacteria in Melon (Cucumis melo L.) Seeds

Endophytic bacteria play a crucial role in the life cycle of Spermatophyta, and exploring the beneficial interactions between seeds and endophytic bacteria is an effective strategy for sustainable agricultural development and improved crop productivity. In this study, we employed Illumina Hiseq high-throughput sequencing technology to analyze the amplified fragments of microbial 16S rRNA sequences from melon seeds of MR-1, HH and their F1 generation, which displayed varying levels of resistance to bacterial fruit blotch disease. Initially, we extracted endophytes from eight melon samples and performed sequencing, obtaining an average of 84,758 effective tags per sample. At the 97% similarity level, the number of operational taxonomic units (OTUs) derived from melon seed endophytes ranged from 447 to 492. After filtering out low-level OTUs, we obtained an average of 65,866 valid tags from the eight samples, representing approximately 160 genera and 167 species across eight phyla. It was found that the composition of the endophyte communities in the eight samples was basically similar, and their abundance showed some variability. Furthermore, we utilized the KO and COG databases to functionally predict the genes of endophytes in melon seeds. The analysis revealed a significant enrichment of genes associated with pathways related to protein synthesis, carbohydrate metabolism, substance transport, and metabolite synthesis. These findings greatly contribute to our understanding of endophytic bacteria in melon seeds and serve as a vital reference for the selection and breeding of high-quality melon seeds, as well as the prevention of seed diseases.

Changes induced by multi-stage water stress on maize growth, water and nitrogen utilization and hormone signaling under different nitrogen supplies

Water availability and nitrogen (N) supply are two major issues that affect plant productivity, however, the processes of water and N utilization and their hormone regulation are not conclusive in response to varying water-N interaction. The objective of this study was to evaluate the effects of water stress (WS) at different growth stages on maize plant development, root morphology, water utilization, hormone signaling and N accumulation under various N conditions. A set of controlled drought stress at 60% field capacity was conducted from bell (V12) to tassel (VT) stage (V12-VT, denoted as W1W2), from silk (R1) to milk (R3) stage (R1-R3, denoted as W2W1) and their compound stages (V12-R3, denoted as W1W1) under high- and low-N supply, respectively. The results indicated that compared to the well-watered control (W2W2), W2W1 reduced root length, root area, and shoot dry matter by 4.68–19.15%, 5.92–11.97% and 4.38–29.61%, respectively, while W1W2 promoted the root system and improved the shoot growth, grain formation and plant water use efficiency (WUEp). High N supply tended to aggravate WS with a poorer root system and lower leaf water potential (ψleaf) but higher leaf abscisic acid (ABA) accumulation at different growth stages. Leaf ABA significantly increased while stomatal conductance (Gs) decreased under WS and N-rich environment, hence increasing leaf intrinsic water use efficiency (WUEi). Root zeatin-riboside (ZR) was higher for well-watered and N-rich conditions. Moreover, leaf ABA significantly increased with the decrease of ψleaf (R2 =0.51 for R3, R2 =0.35 for dough stage (R4)) and the variation of ψleaf was relatively constant (≤0.3 MPa) with different water treatments, indicating that maize performed isohydric behavior to response water stress and N-rich environment. This study suggests that to promote the potential of water- and N-saving and improve crop productivity in maize cultivation, mild water stress at vegetative growth stages and appropriate N supply are of great importance.

Developments and Prospects of Farmland Application of Biogas Slurry in China-A Review.

Biogas slurry (BS) is an attractive agricultural waste resource which can be used to regulate soil microbial communities, enhance nutrient absorption capacity of crops, promote plant-soil interactions, and consequently, increase crop productivity. Presently, BS discharge is not environmentally friendly. It is therefore necessary to explore alternative efficient utilization of BS. The use of BS as fertilizer meets the requirements for sustainable and eco-friendly development in agriculture, but this has not been fully actualized. Hence, this paper reviewed the advantages of using BS in farmland as soil fertilization for the improvement of crop production and quality. This review also highlighted the potential of BS for the prevention and control of soil acidification, salinization, as well as improve microbial structure and soil enzyme activity. Moreover, this review reports on the current techniques, application methods, relevant engineering measures, environmental benefits, challenges, and prospects associated with BS utilization. Lastly, additional research efforts require for optimal utilization of BS in farmlands were elucidated.

Investigation of Amended Sandy Soil's Water Retention Characteristics

Purpose: Soil water retention studies are important for evaluating soil quality and water movement in soils. This study assesses the water content capacity and changes in the retention curve of sandy soil after using zeolite X, activated charcoal, and rice husk ash as amendments. Design/Methodology/Approach: Sandy soil samples were collected from the study area, Keta District of Ghana, and a core borer and a pot experiment were used to determine the pressure head and water content of the soil. One-way analysis of variance (One-way ANOVA) was used to analyze the data. Water retention curve analyses were conducted using COMSOL multi-physics simulation and experimental work. Research Limitation/Implication: The amendments used were restricted to zeolite X, activated charcoal, and rice husk ash. Practical Implications: The study contributes to the field of sustainable agriculture and land management by exploring amendments that can potentially reduce water usage in irrigation, mitigate soil erosion, and enhance soil fertility. This aligns with global efforts to promote sustainable and efficient resource use. Social Implications: These findings can be implemented for cases of poor yield by farming communities by applying zeolite X, activated charcoal, and rice husk ash to improve crop productivity.

Inoculation with Biofilm of Bacillus subtilis Promotes the Growth of Lactuca sativa

In Argentina, the excessive use of fertilizers is common in intensively cultivated zones around highly populated areas. Bioinoculants based on plant growth promoting rhizobacteria (PGPR) could be effective for crop production improvement without negative effects on the environment. The objective of this work was to evaluate an alternative inoculation method, namely the application of the biofilm produced by Bacillus subtilis as a growth promoter on seeds of three varieties of Lactuca sativa, and to compare it with the common planktonic approach. Biofilm was obtained under static culture conditions, while planktonic inoculum was produced at 150 rpm. The major biofilm effects were observed with Bacillus subtilis subsp. spizizenii, that showed antifungal activity against phytopathogens, synthesized plant growth regulators (IAA, cytokinin and ABA) and solubilized phosphates. The Grand Rapid variety inoculated with biofilm showed the best results, with 30% and 37% higher aerial and root biomass, respectively, compared to the planktonic form. Moreover, the biofilm positive effects were observed through successive plant development stages until harvest, when the bacterium was recovered from the interior of the roots. The biofilm of B. subtilis subsp. spizizenii behave as a superior growth-promoting inoculant compared to the traditional planktonic inoculation technique.

Enhancing wheat regeneration and genetic transformation through overexpression of TaLAX1

In the realm of genetically transformed crops, the process of plant regeneration holds utmost significance. However, the low regeneration efficiency of several wheat varieties currently restricts the use of genetic transformation for gene functional analysis and improved crop production. This research explores overexpression of TaLAX PANICLE1 (TaLAX1), which markedly enhances regeneration efficiency, thereby boosting genetic transformation and genome editing in wheat. Particularly noteworthy is the substantial increase in regeneration efficiency of common wheat varieties previously regarded as recalcitrant to genetic transformation. Our study shows that increased expression of TaGROWTH-REGULATING FACTOR (TaGRF) genes, alongside that of their co-factor, TaGRF-INTERACTING FACTOR 1 (TaGIF1), enhances cytokinin accumulation and auxin response, which may play pivotal roles in the improved regeneration and transformation of TaLAX1-overexpressing wheat plants. Overexpression of TaLAX1 homologs also significantly increases the regeneration efficiency of maize and soybean, suggesting that both monocot and dicot crops can benefit from this enhancement. Our findings shed light on a gene that enhances wheat genetic transformation and elucidate molecular mechanisms that potentially underlie wheat regeneration.

Exploring Carbohydrate Concentration Fluctuations in Pistachio (Pistacia vera L. cv Uzun) for Deeper Insights into Alternate Bearing Patterns

Alternate bearing (AB) is of great importance in horticulture and leads to fluctuations in yield variation. Although AB is a natural phenomenon to optimize resource allocation and improve crop productivity and profitability in plants, understanding the factors that influence AB can help in implementing effective management strategies to reduce the negative effects and promote consistent and sustainable production. This study aimed to investigate the variation in carbohydrate levels in various tissues of both bearing and non-bearing pistachio (Pistacia vera L. cv Uzun) trees during different periods of growth development in two consecutive years to gain a deeper understanding of their potential contribution to AB. Twelve 34-year-old pistachio trees, consisting of six “ON” and six “OFF” year trees, were accidentally selected from a pistachio orchard. The “OFF” year trees were induced two years before sampling to be in the “OFF” year state by artificially removing flower buds. Sucrose was the main soluble sugar in the different parts of the pistachio tree studied. In general, the amount of sugar was higher in the non-bearing year than in the bearing year. It was found that non-structural carbohydrates of trees decreased between June and July, resulting in flower buds to abscise. The amount of carbohydrates decreased during nut development in “ON” trees, indicating the possible role of carbohydrates in AB.

Exploring horticultural traits and disease resistance in Capsicum baccatum through segmental introgression lines.

Segmental introgression and advanced backcross lines were developed and validated as important tools for improving agronomically important traits in pepper, offering improved sensitivity in detecting quantitative trait loci for breeding. Segmental introgression lines (SILs) and advanced backcross lines (ABs) can accelerate genetics and genomics research and breeding in crop plants. This study presents the development of a complete collection of SILs and ABs in pepper using Capsicum annuum cv. 'CM334' as the recipient parent and Capsicum baccatum 'PBC81', which displays various agronomically important traits including powdery mildew and anthracnose resistance, as donor parent. Using embryo rescue to overcome abortion in interspecific crosses, and marker-assisted selection with genotyping-in-thousands by sequencing (GT-seq) to develop SILs and ABs containing different segments of the C. baccatum genome, we obtained 63 SILs and 44 ABs, covering 94.8% of the C. baccatum genome. We characterized them for traits including powdery mildew resistance, anthracnose resistance, anthocyanin accumulation, trichome density, plant architecture, and fruit morphology. We validated previously known loci for these traits and discovered new sources of variation and quantitative trait loci (QTLs). A total of 15 QTLs were identified, including four for anthracnose resistance with three novel loci, seven for plant architecture, and four for fruit morphology. This is the first complete collection of pepper SILs and ABs validated for agronomic traits and will enhance QTL detection and serve as valuable breeding resources. Further, these SILs and ABs will be useful for comparative genomics and to better understand the genetic mechanisms underlying important agronomic traits in pepper, ultimately leading to improved crop productivity and sustainability.

Two long read-based genome assembly and annotation of polyploidy woody plants, Hibiscus syriacus L. using PacBio and Nanopore platforms

Improvements in long read DNA sequencing and related techniques facilitated the generation of complex eukaryotic genomes. Despite these advances, the quality of constructed plant reference genomes remains relatively poor due to the large size of genomes, high content of repetitive sequences, and wide variety of ploidy. Here, we developed the de novo sequencing and assembly of high polyploid plant genome, Hibiscus syriacus, a flowering plant species of the Malvaceae family, using the Oxford Nanopore Technologies and Pacific Biosciences Sequel sequencing platforms. We investigated an efficient combination of high-quality and high-molecular-weight DNA isolation procedure and suitable assembler to achieve optimal results using long read sequencing data. We found that abundant ultra-long reads allow for large and complex polyploid plant genome assemblies with great recovery of repetitive sequences and error correction even at relatively low depth Nanopore sequencing data and polishing compared to previous studies. Collectively, our combination provides cost effective methods to improve genome continuity and quality compared to the previously reported reference genome by accessing highly repetitive regions. The application of this combination may enable genetic research and breeding of polyploid crops, thus leading to improvements in crop production.

A systematic review on physical mutagens in rice breeding in Southeast Asia.

In the 1920s, Lewis Stadler initiated the introduction of permanent improvements to the genetic makeup of irradiated plants. Since then, studies related to breeding mutations have grown, as efforts have been made to expand and improve crop productivity and quality. Stadler's discovery began with x-rays on corn and barley and later extended to the use of gamma-rays, thermal, and fast neutrons in crops. Radiation has since been shown to be an effective and unique method for increasing the genetic variability of species, including rice. Numerous systematic reviews have been conducted on the impact of physical mutagens on the production and grain quality of rice in Southeast Asia. However, the existing literature still lacks information on the type of radiation used, the rice planting materials used, the dosage of physical mutagens, and the differences in mutated characteristics. Therefore, this article aims to review existing literature on the use of physical mutagens in rice crops in Southeast Asian countries. Guided by the PRISMA Statement review method, 28 primary studies were identified through a systematic review of the Scopus, Science Direct, Emerald Insight, Multidisciplinary Digital Publishing, and MDPI journal databases published between 2016 and 2020. The results show that 96% of the articles used seeds as planting materials, and 80% of the articles focused on gamma-rays as a source of physical mutagens. The optimal dosage of gamma-rays applied was around 100 to 250 Gy to improve plant development, abiotic stress, biochemical properties, and nutritional and industrial quality of rice.

Mixed application of controlled-release urea and normal urea can improve crop productivity and reduce the carbon footprint under straw return in winter wheat-summer maize cropping system

An important goal of sustainable agriculture is reducing the environmental risk while also ensuring food security. The mixed application of controlled-release urea and normal urea (CRUNU) is a potential nitrogen (N) management strategy for achieving this goal. However, few studies have focused on whether optimizing the N application rate of CRUNU can balance crop yield and greenhouse gas emissions, especially when straw is returned. Thus, we conducted a five-year field experiment in a winter wheat–summer maize planting system in Northwest China to determine the effects of different N fertilizer types (NU: normal urea; CRUNU) and N application levels (low N, 135 kg ha–1; medium N, 180 kg ha–1; high N, 225 kg ha–1) with straw return on the crop yield and stability, N fertilizer partial factor productivity (NFPF), and soil organic carbon (SOC). Life cycle assessment was also conducted to quantify the GHG emissions from farmland and carbon footprint (CF). Compared with NU, CRUNU improved the winter wheat and summer maize grain yield, biomass, and NFPF at all three N application levels. The crop grain yields increased significantly as the N application level increased under NU, but the crop grain yields did not differ significantly between the medium and high N application levels under CRUNU (P > 0.05). The SOC contents increased as the duration of straw return increased. Compared with NU, CRUNU significantly increased the SOC content, and correlation analysis showed that this increase was related to the increased amount of returned straw. Compared with NU, CRUNU increased the GHG emissions in the production process but reduced the GHG emissions in the application process, as well as increasing soil CO2 fixation to ultimately reduce the total GHG emissions. CRUNU increased the crop grain yield while also reducing the total GHG emissions, and thus the CF decreased significantly by 14.53–23.03% compared with NU, especially at the medium N application level. Therefore, this comprehensive analysis of the crop productivity and GHG emissions indicates that CRUNU combined with an appropriate N application level can be used as a nitrogen fertilizer management strategy for sustainable winter wheat–summer maize cropping in Northwest China.

Volatile Compounds Emitted by Plant Growth-Promoting Fungus Tolypocladium inflatum GT22 Alleviate Copper andPathogen Stress.

Previous studies on the intricate interactions between plants and microorganisms have revealed that fungal volatile compounds (VCs) can affect plant growth and development. However, the precise mechanisms underlying these actions remain to be delineated. In this study, we discovered that VCs from the soilborne fungus Tolypocladium inflatum GT22 enhance the growth of Arabidopsis. Remarkably, priming Arabidopsis with GT22 VCs caused the plant to display an enhanced immune response and mitigated the detrimental effects of both pathogenic infections and copper stress. Transcriptomic analyses of Arabidopsis seedlings treated with GT22 VCs for 3, 24 and 48 h revealed that 90, 83 and 137 genes were differentially expressed, respectively. The responsive genes are known to be involved in growth, hormone regulation, defense mechanisms and signaling pathways. Furthermore, we observed the induction of genes related to innate immunity, hypoxia, salicylic acid biosynthesis and camalexin biosynthesis by GT22 VCs. Among the VCs emitted by GT22, exposure of Arabidopsis seedlings to limonene promoted plant growth and attenuated copper stress. Thus, limonene appears to be a key mediator of the interaction between GT22 and plants. Overall, our findings provide evidence that fungal VCs can promote plant growth and enhance both biotic and abiotic tolerance. As such, our study suggests that exposure of seedlings to T. inflatum GT22 VCs may be a means of improving crop productivity. This study describes a beneficial interaction between T. inflatun GT22 and Arabidopsis. Our investigation of microorganism function in terms of VC activities allowed us to overcome the limitations of traditional microbial application methods. The importance of this study lies in the discovery of T. inflatun GT22 as a beneficial microorganism. This soilborne fungus emits VCs with plant growth-promoting effects and the ability to alleviate both copper and pathogenic stress. Furthermore, our study offers a valuable approach to tracking the activities of fungal VC components via transcriptomic analysis and sheds light on the mechanisms through which VCs promote plant growth and induce resistance. This research significantly advances our knowledge of VC applications and provides an example for further investigations within this field.