Yield Reduction Research Articles

Mechanosynthesis of Enaminones and Mechanochemical Telescopic Synthesis of β,γ‐Unsaturated Butyrolactams

The stereoselective mechanochemical synthesis of Z‐enaminones and bis‐enaminones was achieved without any solid component in most cases, reacting 1,3‐dicarbonyl compounds with aliphatic/aromatic primary/secondary amines, which demonstrates the viability of reacting exclusively liquid reagents. The scale‐up was robust, from five to fifty and five hundred mmol without reduction in the reaction yield. The mechanochemical telescopic synthesis of β,γ‐unsaturated butyrolactams was achieved by formal [3+2] azaanulation reaction of intermediate enaminone with maleic anhydride, boosting the access of this potentially bioactive class of compound. The mechanochemical approach revealed its sustainable face in both syntheses, avoiding solid grinding auxiliary and purification by column chromatography. A symbol was suggested to differentiate the representation of the planetary ball mill from other mechanochemical reactors, wherein three spheres are surrounded by two curved arrows representing the two inherent movements of planetary trajectories of the reaction vessel of this equipment.

Evaluation of Novel Picolinamide Fungicides (QiI) for Controlling Cercospora beticola Sacc. in Sugar Beet

Studies were initiated to find new effective fungicides to use under field conditions to discover novel approaches for optimizing disease management in sugar beet crops. Cercospora leaf spot (CLS), a prevalent foliar disease in sugar beet crops worldwide, is caused by the fungal pathogen Cercospora beticola Sacc. This disease has become the most prevalent pathogen in sugar beet crops across nearly all European growing regions, including Hungary. The epidemic spread of this disease can cause up to 50% yield loss. The use of fungicides has been a cornerstone in managing CLS of sugar beet due to the limited efficacy of non-chemical alternatives. However, the emergence of fungicide-resistant strains of Cercospora beticola Sacc. in recent decades has compromised the effectiveness of certain fungicides, particularly those belonging to the QoI (FRAC Group 11) and DMI (FRAC Group 3) classes. Hungary is among the many countries where resistance to these fungicides has developed due to their frequent application. Picolinamides represent a novel class of fungal respiration inhibitors targeting Complex III within the Quinoine-Inside Inhibitor (QiI) group. Two innovative fungicides from this class, fenpicoxamid and florylpicoxamid (both classified under FRAC Group 21), were evaluated for their efficacy in managing CLS of sugar beet in Hungary during the 2020 and 2021 growing seasons. Both fungicides were applied as formulated products at various application rates and demonstrated superior efficacy in controlling CLS compared to untreated control plots and the reference fungicides difenoconazole and epoxiconazole. The results consistently demonstrated that all tested application rates of fenpicoxamid and florylpicoxamid effectively controlled CLS in sugar beet, exhibiting a clear dose–response relationship. Disease severity, as measured by the area under the disease progress curve (AUDPC), was significantly correlated with yield reduction but showed no significant association with root sugar content. Moreover, data from both study years indicated that picolinamide fungicides applied at a rate of 75 g ai/ha significantly outperformed difenoconazole (100 g ai/ha) in controlling the CLS of sugar beet. Additionally, higher application rates of picolinamides at 100–150 g ai/ha outperformed epoxiconazole at 125 g ai/ha in disease suppression. Fenpicoxamid is currently registered for use in cereals within Europe, and outside of Europe in Banana against Black Sigatoka (eff. Mycosphaerella fijiensis). Florylpicoxamid, while not yet registered in Europe, is undergoing approval processes in various countries worldwide for a range of crops and is continually being evaluated for potential market introduction. Additional details regarding the efficacy of florylpicoxamid against CLS in sugar beet were presented at ‘The 10th International Conference on Agricultural and Biological Sciences (ABS 2024, Győr-Hungary)’ in 2024.

Effects of Fresh and Composted Azolla on Soil Chemical Properties

The rise in chemical fertilizer use in Malaysia raises concerns about soil degradation and potential long-term yield reductions, highlighting the importance of using organic matter for soil restoration. Azolla has been extensively studied as an alternative soil amendment due to its high nitrogen and nutrient content, as well as its rapid growth. However, the effects of fresh and composted Azolla amendments on soil chemical properties are not yet fully understood. A soil incubation study was thus conducted to determine the effects of fresh and composted Azolla on soil chemical properties over a 3-month incubation period. The soil treatments consisted of non-amended soil (control); fresh Azolla at 3, 6, and 9% w/w; and composted Azolla at 1, 2, and 3% w/w, with soil water holding capacity maintained at 55% throughout the incubation period. The collected soil samples were analyzed for soil pH and electrical conductivity (EC), total carbon (C) and nitrogen (N), available phosphorus, exchangeable bases—potassium (K), calcium, and magnesium, using inductively coupled plasma optical emission spectrometry, and cation exchange capacity (CEC). All data were subjected to variance analysis for statistical analysis. The study revealed significant effects of interaction between soil treatments and incubation periods for all soil parameters. At the end of the incubation period, the soil treated with 3% composted Azolla exhibited higher soil EC, total C and N, exchangeable K, and CEC compared to other soil treatments. The 3% fresh Azolla treatments were also observed to improve the soil’s exchangeable calcium by the end of the incubation period. In conclusion, 3% composted Azolla is best to help restore soil nutrient levels for crop uptake.

Evaluating the impact of Cold plasma on Seedling Growth properties, seed germination, and soybean antioxidant enzyme activity.

Cold atmospheric pressure plasma (CAP) has garnered significant attention in recent years for its potential applications in biomedical, environmental, and agricultural fields. Cold plasma treatment exhibits a variety of effects in agricultural applications, including impacts on seed germination and seedling growth; however, further research is required. Soybean serves as a fundamental source of nutrients for both animals and humans. Soybean seeds possess impermeable and thick testae, which results in prolonged germination times and suboptimal germination rates. The soybeans exhibit low uniformity. As a result, poor crop establishment and yield reduction are inevitable outcomes. Therefore, the purpose of this study was to examine the effects of Iranian soybean cultivars, such as Sari, Saba, Arian, Katoul, and Williams, on seedling growth properties, seed germination, and antioxidant enzyme activity, using argon at time intervals of 30, 60, 180, 300, and 420s. Cold plasma treatment significantly enhanced germination potential from 1.18 to 66.97%, germination index from 0.50 to 60.09%, germination rate from 1.78 to 32.17%, seedling length from 2.70cm to 78.13cm, root length from 2.87cm to 56.13cm, and seedling dry weight from 1.80g to 36.63g. Additionally, CAT activity increased from 0.88- to 4.40-fold, SOD activity from 0.86- to 5.89-fold, and APX activities from 0.40- to 4.01-fold compared to the control treatment. The findings indicated that the samples exhibited optimal results at treatment durations of 60 and 180s. The influence of plasma on the antioxidant responses of seedlings, seed germination, and growth characteristics was contingent upon the duration of treatment. Cold plasma, when applied for an appropriate duration, may enhance soybean seedling growth characteristics and seed germination.

Effects of cypermethrin on morphological, physiological and biochemical attributes of Cicer arietinum (Fabales: Fabaceae)

Cypermethrin, a synthetic pyrethroid, is a widely employed pesticide in large-scale commercial agriculture and domestic settings to control pests and boost crop yields. Despite its effectiveness in controlling pests, concerns persist about the potential ecological and human health impacts associated with its use. In the present study, the impact of cypermethrin on different parameters, including growth indices, pollen morphology and pollen fertility, chlorophyll and carotenoid content, hydrogen peroxide (H2O2) scavenging, lipid peroxidation (MDA concentration), superoxide dismutase (SOD), and catalase (CAT) activities, was investigated in Cicer arietinum L. The results showed that plants exhibited decreasing trends in plant height, number of branches, pods, and seeds per plant as cypermethrin concentrations increased. These changes resulted in significant reductions in the overall yield of the plants. The percentage of wrinkled pollen significantly increased with higher concentrations of cypermethrin and longer exposure durations. Exposure to cypermethrin showed significant variations in pollen fertility of C. arietinum at different concentrations and time intervals in comparison to control, which had a baseline pollen fertility of 79.12% ± 4.59. Chlorophyll and carotenoid content of C. arietinum were considerably affected by cypermethrin, indicative of potential disturbances in essential photosynthetic processes crucial for plant health. Further, with increasing concentrations of cypermethrin ranging from 100 mg/L to 500 mg/L, noticeable effects were observed on H2O2− scavenging, MDA concentration, SOD and CAT activities of C. arietinum in dose-dependent manner. Further, it was found that the duration of exposure and concentration of cypermethrin played a crucial role in exacerbating these detrimental effects. The findings of the present study raise concerns regarding the harmful effects of agricultural pesticides like cypermethrin and highlight the need for more research on the nutritional value of products derived from plants and seeds exposed to these agents.

A Novel Ah-miR2916-AhERF13-AhSUC3 Module Regulates Al Tolerance via Ethylene-Mediated Signaling in Peanut (Arachnis hypogea L).

Aluminum (Al) toxicity in acidic soils leads to a considerable reduction in crop yields. MicroRNAs play essential roles in abiotic stress responses, but little is known of their role in the response of peanut (Arachnis hypogea L.) to Al stress. In this study, a novel Ah-miR2916 (miR2916)-AhERF13-AhSUC3 module was found to be involved in the Al-stress response via ethylene-mediated signaling in peanut. Overexpression of miR2916 in Arabidopsis resulted in reduced Al tolerance by downregulating ethylene biosynthesis, while knockdown miR2916 in peanut enhanced Al tolerance. Notably, the APETALA2/ethylene-responsive factor (ERF), AhERF13, was identified as a potential target of miR2916. AhERF13 expression was increased in miR2916 knockdown peanut lines and displayed an opposing pattern to that of miR2916 under Al stress. Consistently, knockdown AhERF13 peanut lines indicated that AhERF13 positively regulates Al tolerance by upregulating ethylene biosynthesis. AhERF13 was shown capable of binding to an ERF motif in the promoter region of sucrose transport protein 3 (AhSUC3) and positively regulate its expression. Consequently, AhSUC3 improved Al tolerance by upregulating ethylene biosynthesis. These results provide further insights into the molecular mechanisms operating during peanut response to Al stress, and suggests targets for manipulation in breeding programs for improved Al tolerance.

The Possibility of Environmentally Sustainable Yield and Quality Management of Spring Wheat (Triticum aestivum L.) of the Cornetto Variety When Using Sapropel Extract

Sustainable development is one of the main directions of modern agriculture. First of all, sustainability in the agricultural sector can be achieved through the possible abandonment of traditional mineral fertilizers. Many decades of using these fertilizers have led to the degradation of arable soils and to soil and environmental pollution. As a result, this causes reductions in yields and the environmental quality of agricultural products and affects the health of the population. An alternative to traditional mineral fertilizers may be the use of innovative organomineral fertilizers obtained from local resources. These include manure, humus, compost, sediments, etc. In recent years, fertilizers obtained from the sapropels of the bottom sediments of lakes have become widespread. Their distinctive feature is the environmental friendliness and completeness of the content of chemical elements and substances necessary for the development and growth of plants. In addition, the methods of obtaining and applying these fertilizers allow us to talk about their effectiveness in use. The range of applications of these fertilizers is diverse, from use in the form of a dry extract applied directly to the soil to the use of liquid suspensions used at various stages of processing and from pre-sowing seed treatment to watering and spraying plants at different periods of vegetation. Moreover, an important aspect is the research work on the variational use of sapropel fertilizers on different crops, with different methods of production and concentrations and at different stages of processing. This publication contains the results of a study of the effect of the obtained innovative sapropel fertilizer on productivity, wheat grain quality, and economic efficiency (Triticum aestivum L.). To identify the optimal concentration of sapropel extract, laboratory studies were carried out to determine the germination energy and germination of wheat seeds of different varieties when they were soaked in various concentrations: 0.4, 0.8, 1.2, 1.6, and 2.0 g/L. The best indicators of germination energy and germination of wheat seeds during treatment with the extract were obtained at a concentration of 1.2 g/L. The research was conducted at an accredited variety testing laboratory. A field experiment was conducted in the fields of the agrobiological station of North Kazakhstan University named after Manash Kozybayev. The treatment of the seeds was carried out by soaking them in sapropel extract to evenly distribute the substance. The scheme of the field experiment included the option of using foliar treatment with a solution of sapropel extract at the tillering stage. As a result of the application of the obtained extract in the field, environmental and socio-economic efficiency was noted. The conducted field studies note its positive effect and effectiveness on the morphological, qualitative, and quantitative indicators of the wheat harvest. In the areas where wheat seeds were pretreated, as well as where foliar treatment with the resulting sapropel suspension was carried out, the best yield indicators were revealed. In these variants of the experiment with pre-sowing and pre-sowing and foliar treatment with the sapropel extract solution, the yield was 3.63 and 3.81 tons per hectare, respectively. The introduction of sapropel extract at the stage of seed treatment before sowing, as well as foliar processing of wheat at the tillering stage, will increase the efficiency and profitability of the agricultural industry and obtain a synergistic effect in the form of socio-economic efficiency and environmental safety of production. In our opinion, this will contribute to the development of sustainable agriculture and the production of environmental products.

Genome-wide analysis of quorum sensing regulon in marine fish pathogen Vibrio scophthalmi.

Opportunistic fish pathogen Vibrio scophthalmi frequently infects olive flounder and turbot, which are primary marine species cultured for seafood production in Far East Asia. These infections cause substantial yield reductions and significant economic losses. Although quorum sensing (QS) genes were previously reported in V. scophthalmi, the impacts of QS on genome-wide gene expression and consequent behaviors and physiological traits have remained largely unexplored. In this study, we conducted genomic and transcriptomic analyses to uncover the global regulatory network governed by LuxRVs, a QS master regulator in V. scophthalmi. By comparing the wild-type strain and a luxRVs deletion mutant strain, we found that LuxRVs positively regulates biosynthetic genes for poly-hydroxyalkanoate (PHA) while negatively controlling genes for biofilm formation. Quantification of intracellular PHAs and biofilm biomass on borosilicate tubes confirmed these results. Gene set enrichment analyses further demonstrated that LuxRVs also governs genes related to osmoprotection and defense against reactive oxygen species. Overall, these findings indicate that LuxRVs acts as a global transcriptional regulator, controlling a wide range of physiological processes in V. scophthalmi. Targeting LuxRVs could therefore be a promising strategy for improving seafood production by disrupting diverse physiological and pathogenic traits in this fish pathogen.

Determine the Balance of Nitrogen, Potassium, and Silicon Fertilization for the Control of Rice Tungro Disease Using Response Surface Methodology

This study evaluates the efficacy of combined N, K, and Si treatments to find the balance of these three elements for tungro disease control and rice grain production. The study was conducted in a pot under a glasshouse. These elements were chosen as several findings have indicated the positive benefits of nitrogen (N), potassium (K), and silicon (Si) fertilization on plant development, yield, and biotic stress relief. The methods used were central composite design and response surface methodology. Complete and balanced nutrition has always been the first line of defense for plants due to the direct involvement of mineral elements in plant protection. The results showed that rice tungro disease could be controlled with 138:42:62:200 (N:P2O5:K2O:Si). A high rate of nitrogen is needed to reduce disease development. The results on N may explain that not all conditions of rice plants are at risk with high N rates. Adding Si fertilizer contributes to plant defense mechanisms and plays a role in yield formation. In contrast, the balance of fertilizer for maximizing grain yield per plant was found to be not dependent on nitrogen but needed either low K (62 kg K2O/ha) or high K (80 kg K2O/ha) but with moderate Si (150 kg Si/ha). Prioritizing tungro disease control and adopting the rate of N:K2O:Si (138:62:200), it was found that there was a yield reduction of an average of 7.7%.

Performance of Bt cotton evaluated in relation to mulching and weed control measures in northwest India

BackgroundWeed infestation in cotton has been reported to offer severe competition and cause yield reduction to a large extent. Weeding via cultural practices is time consuming, tedious, and expensive due to long duration of cotton crop and regular monsoon rains during cotton production in India. Chemical weed control has been successfully utilized in cotton in the recent past. However, continuous use of similar herbicides leads to resistance in weeds against herbicides. And when sprayed to the field, herbicides not only suppress weeds but leave undesirable residues in the soil that are hazardous to the environment. Therefore, a study was performed at cotton research area at Chaudhary Charan Singh Haryana Agricultural University, Hisar, Haryana during two consecutive kharif seasons (2020 and 2021) to determine the most suitable and sustainable weed management strategy through the integration of chemical and cultural methods.ResultsMulching with rice straw of 7.5 t ha−1 resulted in significantly higher cotton seed yield (3 189 and 3 084 kg ha−1) and better weed control in comparison to no mulch treatments (2 990 and 2904 kg ha−1) in 2020 and 2021, respectively. Among various weed management levels, the significantly lowest cotton seed yield was recorded in untreated control (1 841 and 1 757 kg·ha−1 during 2020 and 2021, respectively) in comparison to other treatments while all other treatments were statistically at par with each other during both years of crop experimentation.ConclusionMulching with rice straw of 7.5 t·ha−1 along with a pre-emergence application of pendimethalin (active ingredient) at 1.5 kg·ha−1fb (followed by) one hoeings at 45 days after sowing (DAS) and fb glyphosate 2 kg·ha−1 (Shielded spray) at 90 DAS is a viable option for effective control of grassy and broadleaved weeds in Bt cotton in north-west India.

Association of the benzoxazinoid pathway with boron homeostasis in maize.

Both deficiency and toxicity of the micronutrient boron lead to severe reductions in crop yield. Despite this agricultural importance, the molecular basis underlying boron homeostasis in plants remains unclear. To identify molecular players involved in boron homeostasis in maize (Zea mays L.), we measured boron levels in the Goodman-Buckler association panel and performed genome-wide association studies. These analyses identified a benzoxazinless (bx) gene, bx3, involved in the biosynthesis of benzoxazinoids, such as DIMBOA, which are major defense compounds in maize. Genes involved in DIMBOA biosynthesis are all located in close proximity in the genome, and benzoxazinoid biosynthesis mutants, including bx3, are all DIMBOA deficient. We determined that leaves of the bx3 mutant have a greater boron concentration than those of B73 control plants, which corresponded with enhanced leaf tip necrosis, a phenotype associated with boron toxicity. By contrast, other DIMBOA-deficient maize mutants did not show altered boron levels or the leaf tip necrosis phenotype, suggesting that boron is not associated with DIMBOA. Instead, our analyses suggest that the accumulation of boron is linked to the benzoxazinoid intermediates indolin-2-one (ION) and 3-hydroxy-ION. Therefore, our results connect boron homeostasis to the benzoxazinoid plant defense pathway through bx3 and specific intermediates, rendering the benzoxazinoid biosynthesis pathway a potential target for crop improvement under inadequate boron conditions.

Study on optimization of maize irrigation scheduling in Shaanxi Province

With the impact of climate change in recent years, the instability of precipitation and the increase of evaporation have made water resources in Shaanxi Province more and more stressed. How to maintain stable economic development while ensuring the sustainable development of agriculture within the limited water resources has become an important issue facing Shaanxi Province. This paper analyzes the temporal and spatial distribution characteristics of maize irrigation water requirement in Shaanxi Province based on meteorological data and obtains the ideal irrigation water requirement. However, considering the agricultural water scarcity issue in this region, this paper establishes different water scarcity scenarios, adopts the Jensen model to construct an objective function aimed at minimizing crop yield reduction, and solves it using a genetic algorithm to obtain the optimized maize irrigation scheduling under different water scarcity scenarios. The results analysis indicates the following: (1) The effective rainfall in Shaanxi Province from 1960 to 2019 shows a slight upward trend, while the maize water requirement and maize irrigation water requirement shows a downward trend. (2) The spatial distribution of maize irrigation water requirement in Shaanxi Province decreases gradually from north to south. High-value areas are mainly distributed in the northern regions of Yulin City and Yan’an City in Shanbei. Low-value areas are distributed in Ankang City in Shannan. (3) In the face of water scarcity, spring maize should ensure water use during the middle growth period, fast development period, and initial growth periods. Under the same water scarcity conditions, the yield reduction rate is the highest in Guanzhong, followed by the Shannan, and the lowest in Shanbei. This paper aims to provide a scientific and reasonable optimization plan for maize irrigation in Shaanxi Province by calculating and analyzing the maize irrigation water requirement in Shaanxi Province, combined with optimization tools such as genetic algorithms, to address the challenges brought by water resource constraints.

Comparative transcriptome analysis of maize (Zea mays L.) seedlings in response to copper stress.

Copper (Cu) is considered one of the major heavy metal pollutants in agriculture, leading to reductions in crop yield. To reveal the molecular mechanisms of resistance to copper stress in maize (Zea mays L.) seedlings, transcriptome analysis was conducted on the hybrid variety Zhengdan 958 exposed to 0 (control), 5, and 10 mM Cu stress using RNA-seq. In total, 619, 2,685, and 1,790 differentially expressed genes (DEGs) were identified compared to 5 mM versus 0 mM Cu, 10 mM versus 0 mM Cu, and 10 mM versus 5 mM Cu, respectively. Functional categorization of DEGs according to Gene Ontology revealed that heme binding, defense response, and multiorganism processes were significantly enriched under copper stress. Additionally, Kyoto Encyclopedia of Genes and Genomes enrichment analysis suggested that the copper stress response is mediated by pathways involving phenylpropanoid biosynthesis, flavonoid biosynthesis, and glutathione metabolism, among others. The transcriptome data demonstrated that metabolite biosynthesis and glutathione metabolism play key roles in the response of maize seedlings to copper stress, and these findings provide valuable information for enhancing copper resistance in maize.

Impact of tillage methods and cultivars on phenology & productivity of wheat-rice system under irrigated conditions

The research was conducted at the Agricultural Research farm of the Agronomy Department at Palampur, Chaudhary Sarwan Kumar Himachal Pradesh Krishi Vishvavidyalaya (CSK HPKV) and Rice and Wheat Research Center (RWRC) Malan, Himachal Pradesh to study the impact of tillage methods & crop species on phenology & production of wheat-rice crops under irrigated conditions. The study's basic premise was to identify wheat and rice cultivars that can perform well under specific tillage options. The trial was conducted from the winter 2019 to the rainy season of 2021, using a split-plot design. Four tillage methods- zero tillage, conventional tillage, natural farming and reduced tillage- were tested on three species of rice (HPR 2656 (Him Palam Dhan 1), HPR 2795 (Him Palam Dhan Lal 1) & HPR 1156 (Sukara Dhan Lal 1) and three species of wheat (HPW 368 (Him Palam Gehun 2), HS 562 (Central Dwarf wheat) & HPW 349). The results showed that in both crops, traditional farming (conventional tillage) methods were more efficient than other methods in terms of crop yield.Conversely, the lowest grain yields were observed with natural farming for both crops. Specifically, the adoption of zero tillage, natural agriculture, and reduced tillage results in wheat grain yield reductions of 10.9%, 4.6%, and 59.4%, respectively, compared to conventional tillage. Similarly, rice grain yields declined by 10.8%, 34.0%, and 16.1% with zero tillage, natural farming, and reduced tillage, respectively, compared to conventional tillage. Among the cultivars evaluated, HPW 368 for wheat and HPR 2795 for rice produced significantly higher grain yields at both locations over the two years. The findings of the present investigation would help the wheat and rice growers identify suitable cultivars that would be economically grown with varying tillage options and under natural farming conditions.

Efficacy of L-arabinose in managing cucumber Fusarium wilt and the underlying mechanism of action.

Cucumber Fusarium wilt (CFW), triggered by Fusarium oxysporum f. sp. cucumerinum, leads to substantial yield reductions in global cucumber (Cucumis sativus L.) production. Common management strategies for CFW include soil fumigation, grafting, and crop rotation. However, these methods have limitations regarding safety and efficacy stability, necessitating the development of new, cost-effective, and eco-friendly control strategies. Our prior research demonstrated that L-arabinose, an inexpensive and safe sugar commonly used in food and beverages, effectively suppressed bacterial wilt in tomatoes. This study explores the potential of L-arabinose in managing CFW and investigates its mechanism of action. Soil applications of L-arabinose, ranging from 0.00001 to 0.01%, effectively suppressed CFW. The most significant suppressive effect was observed at 0.01%, reducing the disease severity index by 67.5% compared to the control treatment. Microscopic examination of transverse root sections showed that pathogen hyphae colonized the epidermis but seldom penetrated the cortical layer of roots in L-arabinose-treated seedlings. In contrast, the entire root tissue of control seedlings was colonized by the pathogen. Quantitative real-time PCR revealed a significant increase in the expression of defense-related genes dependent on salicylic acid, jasmonic acid, and ethylene in L-arabinose-treated plants compared to control plants, 6 and 10 days post pathogen inoculation. This study demonstrated that soil application of L-arabinose can effectively suppress CFW by priming root tissues for multiple defense signaling pathways. Therefore, L-arabinose holds potential as a new fungicide for managing CFW. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Genetic Diversity Analysis of Rice (Oryza sativa L.) Genotypes for Yield and Sheath Blight Screening

Sheath blight disease, caused by Rhizoctonia solani Kühn, is considered the second most important disease affecting rice, causing yield reduction globally. In the present study thirty diverse rice genotypes were inoculated with fungal mycelia during the maximum tillering stage to assess the genetic diversity of rice genotypes for sheath blight reactions. Mahalanobis D2 statistics was performed for grain yield and yield contributing features under sheath blight stress to calculate the genetic divergence between the genotypes. Four clusters were formed from the genotypes. Cluster III has the highest number of genotypes (nine). The highest inter-cluster distance was noticed between cluster I and cluster IV (11.41) and minimum between cluster III and cluster IV (6.50). The intra-cluster distances were lower, indicating the homogeneity of the genotypes within the clusters. Maximum intra-cluster D2 value was recorded in cluster IV (6.32) and minimum in cluster II (5.36). Cluster I showed high genetic divergence from all other clusters. Hence, the genotypes from cluster I could be used for hybridization with the genotypes of other clusters to develop high yielding sheath blight resistant rice varieties.

New ozone–nitrogen model shows early senescence onset is the primary cause of ozone-induced reduction in grain quality of wheat

Abstract. Ozone (O3) air pollution is well known to adversely affect both the grain and protein yield of wheat, an important staple crop. This study aims to identify and model the key plant processes influencing the effect of O3 on wheat protein. The DO3SE-Crop model was modified in this work to incorporate nitrogen (N) processes, and we parameterised the O3 effect on stem, leaf, and grain N using O3 fumigation datasets spanning 3 years and four O3 treatments. These modifications mean that the newly developed DO3SE-CropN model is the first crop model to include O3 effects on N processes, making it a valuable tool for understanding O3 effects on wheat quality. Our results show that the new model captures the O3 effect on grain N concentrations and the anthesis leaf and stem concentrations well, with an R2 of 0.6 for the increase in grain N concentration and an R2 of 0.3 for the decrease in grain N content under O3 exposure. However, the O3 effect on harvest leaf and stem N is exaggerated. Overestimations of harvest leaf N range from ∼20 % to 120 %, while overestimations of harvest stem N range from ∼40 % to 120 %. Further, a sensitivity analysis revealed that, irrespective of O3 treatment, early senescence onset (simulated as being ∼13 d earlier in the treatment with very high O3 vs. the low-O3 treatment) was the primary plant process affecting grain N. This finding has implications for the breeding of stay-green cultivars for maintaining yield, as well as quality, under O3 exposure. This modelling study therefore demonstrates the capability of the DO3SE-CropN model to simulate processes by which O3 affects N content and, thereby, determines that senescence onset is the main driver of O3 reductions in grain protein yield. The implication of the sensitivity analysis is that breeders should focus their efforts on stay-green cultivars that do not experience a protein penalty when developing O3-tolerant lines, to maintain both wheat yield and nutritional quality under O3 exposure. This work supports the second phase of the Tropospheric Ozone Assessment Report (TOAR) by investigating the impacts of tropospheric O3 on wheat, with a focus on wheat quality impacts that will subsequently affect human nutrition.

Long-term alfalfa planting mediates the coupling of soil water and organic carbon storage in a semi-arid area of the Loess Plateau, China.

The key to restoring arid and semi-arid ecosystems is maintaining soil water and organic carbon contents. Alfalfa (Medicago sativa L.) is a high-yield perennial forage crop and performs ecological functions as a drought-resistance leguminous herb. It has been widely planted for reconstruction of degraded soils in the Loess Plateau in northwestern China, but long-term planting may affect soil carbon-water coupling and lead to crop yield reduction. To maximize the benefits of reconstructed grassland, this study explored the couplings of soil water, organic carbon, and alfalfa productivity along a reconstruction chronosequence in a semi-arid area of the Loess Plateau. Space-for-time substitution approach was used to select different-aged stands of reconstructed grassland (1, 5, 7, 10, 15, 20, 30 years old). Alfalfa above-ground biomass (AGB), soil water storage (SWS), organic carbon storage (SOCS), and carbon-water coupling coordination degree (D) were measured in the 0-100 cm soil profile. Alfalfa AGB reached a peak in the 7th year, and the degradation began in the 10th year. Both SWS and SOCS varied nonlinearly with stand age. The greatest loss of SWS occurred in the 15th year (80-100 cm depth), whereas the largest increase of SOCS occurred in the 30th year (0-20 cm depth). There was a negative feedback relationship between AGB and SWS over the 30-year study period (Pearson r = -0.835, P = 0.098). AGB and SOCS initially showed a trade-off within the first 10 years (Pearson r = -0.7431, P = 0.2569), in contrast to their positive feedback in the 20-30th years (Pearson r = 0.9978, P = 0.0421). A decoupling between SWS and SOCS (D < 0.6) was observed after 12 years of alfalfa planting. For agricultural production, a greater supply of water and organic fertilizer is required from the 7th year of alfalfa planting, and reseeding may be needed around the 10th year to prolong the life of alfalfa community. Alfalfa should be planted for no more than 12 consecutive years in the study area for ecological protection.

Leaf Photosynthetic and Photoprotective Acclimation in the Ultraviolet-A1 and Blue Light Regions Follow a Continuous, Shallow Gradient.

Although blue light is known to produce leaves with high photosynthetic capacity, the role of the blue-adjacent UV-A1 (350-400 nm) in driving leaf photosynthetic acclimation is less studied. Tomato plants were grown under hybrid red and blue (RB; 95/5 μmol m-2 s-1), as well as four treatments in which RB was supplemented with 50 μmol m-2 s-1 peaking at 365, 385, 410 and 450 nm, respectively. Acclimation to 365-450 nm led to a shallow gradient increase in trait values (i.e., photosynthetic capacity, pigmentation and dry mass content) as the peak wavelength increased. Furthermore, both UV-A1 and blue light grown leaves showed efficient photoprotection under high light intensity. When treated plants were transferred to fluctuating light for 5 days, leaves from all treatments showed increases in photosynthetic capacity, which were strongest in RB, followed by additional UV-A1 treatments; RB grown leaves showed reductions in maximum quantum yield of photosystem II, while UV-A1 grown leaves showed increases. We conclude that both UV-A1 and blue light effectively trigger photosynthetic and photoprotective acclimation, the extent of acclimation becoming stronger the longer the peak wavelength is. Acclimatory responses to UV-A1 and blue light are thus not distinct from one another, but follow a continuous gradient.

Functional groups of leaf phenology are key to build climate-resilience in cocoa agroforestry systems

Agroforestry has the potential to enhance climate change adaptation. While benefits from agroforestry systems consisting of cash crops and shade trees are usually attributed to the (shade) trees, the trees can also have negative impacts due to resource competition with crops. Our hypothesis is that leaf phenology and height of shade trees determine their seasonal effect on crops. We test this hypothesis by categorizing shade tree species into functional groups based on leaf phenology, shade tree canopy height and shade tree light (wet and dry season) interception as well as the effects. To this end, leaf phenology and the effects on microclimate (temperature, air humidity, intercepted photoactive radiation (PAR)), soil water, stomatal conductance and cocoa yield were monitored monthly during wet and dry seasons over a two-year period on smallholder cocoa plantations in the northern cocoa belt of Ghana. Seven leaf phenological groups were identified. In the wet season, highest buffering effect of microclimate was recorded under the trees brevi-deciduous before dry season. During dry season, high PAR and lowest reduction in soil moisture were observed under the trees in the group of completely deciduous during dry season. The evergreen groups also showed less reduction in soil water than the brevi-deciduous groups. In the wet season, shade tree effects on cocoa tree yields in their sub canopy compared to the respective control of outer canopy with full sun ranged from positive (+10 %) to negative (-15 %) for the deciduous groups, while yield reductions for the evergreen groups ranged from −20 % to −33 %. While there were negative yield impacts for all phenological groups in the dry season, the trees in completely deciduous during dry season group recorded least penalties (-12 %) and the trees with evergreen upper canopy the highest (-35 %). The function of shade trees in enhancing climate resilience is therefore strongly dependent on their leaf phenological characteristics. Our study demonstrates how the key trait leaf phenology can be applied to successful design of climate-resilient agroforestry systems.