Yield Loss Research Articles

The Effect of Border Crops and Physical Barriers on Incidence of Chilli Leaf Curl Complex and Associated Insect Populations

Chilli Leaf Curl (CLC) possesses a significant biotic threat leading to substantial yield losses in chilli cultivation. Various agents such as thrips, aphids, mites and the viruses transmitted by whiteflies have been identified as contributors to CLC. In order to mitigate this issue, three types of physical barriers were used: an insect-proof net (1 m high) surrounded by three rows of maize crops, an insect-proof net (1 m high) alone, and three rows of maize crops. A control was maintained without a physical barrier. The experiment was laid out as randomized complete block design with three replicates. Identification of pests and diseases, CLC disease incidence and yield attributes were assessed. Results revealed that the treatment with an insect-proof net combined with a maize border exhibited the lowest disease incidence (2±0.45, p=0.01) compared to chilli plants with a maize border only. The whitefly population varied across the treatments (p=0.03) and with the age of the crop (p<0.0001). Among the treatments, the control and insect-proof net exhibited a significantly lower population of whiteflies. Thrips did not show a significant response to the treatments (p=0.54) indicating that the presence of physical barriers had no notable effect on thrips counts. Additionally, there was no significant difference in the number of pods per plant (p=0.74) and yield per plant across the treatments (p=0.54). In conclusion, the use of insect-proof net with a maize border surrounding the chilli cultivation would help to develop integrated pest management strategies to reduce chilli leaf curl incidence as well as whitefly population.

Exploring the impact of aminoethoxyvinylglycine (AVG) on the ripening behaviour and quality of bananas under different storage conditions

ABSTRACT Bananas rapidly undergo physiological deterioration after harvest owing to their climacteric and perishable nature causing significant economic yield loss. Thus, the adoption of postharvest loss mitigation strategies becomes imperative for enhancing fruit longevity. This study aimed to assess the effect of postharvest treatment with different concentrations of aminoethoxyvinylglycine (AVG) on shelf life extension and quality sustainability of bananas, such as Grand Naine, Poovan and Ney Poovan, kept under ambient (27°C ± 2°C) and cool (17°C) conditions. The findings revealed that AVG-treated bananas reduced weight loss of banana hands (0.655–2.559 kg hand−1) and higher peel thickness (0.86–2.73 mm) and firmness (6.54–12.01 N) over untreated control at ambient storage condition, whereas under cool storage, weight loss of banana hands reduced from 0.761 to 2.579 kg hand−1, while both peel thickness (1.24–2.84 mm) and firmness (7.75–11.45 N) were retained for varieties. The physio-chemical traits of fruit, such as total chlorophyll and starch content, were improved due to AVG treatment under both storage conditions. Among the treatments, postharvest application of AVG at 700 ppm showed better performance in the morphological, physiological and quality characters irrespective of the varieties.

Successful NH3 abatement policies and regulations in German agriculture

Anthropogenic ammonia (NH3) emissions, of which about 95 % are from agriculture, have led to environmental pollution, resulting in tremendous damage to human health and ecosystems. Thus, the NEC Directive 2016/2284/EU sets national reduction targets for NH3 emissions in individual EU countries. To implement the NEC Directive for NH3 emission targets, Germany amended the Fertilizer Application Ordinance in 2017 and 2020 (DüV_amended) and set the air pollution control regulation, Technical Instructions on Air Quality Control (TA_Luft). This study aimed to evaluate the impact of the DüV_amended on NH3 mitigation from applying livestock manure, digestates, synthetic nitrogen (N) fertilizers, and TA_Luft on housing and storage. This study showed that Germany reached the first national NH3 reduction target in 2020, as set by the NEC directive. The German DüV_amended, a significant policy change, has profoundly impacted NH3 emission mitigation from agriculture after 2017 by implementing measures aimed directly at NH3 reduction, reducing N surpluses, and improving N use efficiency. The reduction in NH3 emissions from synthetic N fertilizers between 2016 and 2022 contributed about 51 % to the decrease from the agricultural sector over the same period. Among the synthetic fertilizers, NH3 reduction from urea between 2016 and 2022 accounted for around 83 % of the total reduction from synthetic N, indicating that the NH3 emissions from urea fertilizer by reducing urea application and mandating urea to be incorporated immediately or to be stabilized with urease inhibitors played a crucial role in the sharp decrease in NH3 emissions over the last years in Germany. Achieving a high yield by lowering the synthetic N rate in this study strongly suggests that optimal reduction in N rate does not necessarily result in yield losses but rather in a pivotal relationship between the agronomic and environmental performance and indicates that the DüV_amended was an effective measure that can reduce the NH3 emissions.Over 80 % of Germany's annual agricultural NH3 emissions in 2021 and 2022 originated from livestock and digestates from energy crops. Mandatory close to the soil band application of slurry and digestates on cultivated cropland since 2020 reduced NH3 emissions. In addition, banning of broadcast application of slurry to grassland and manure incorporation within one hour on uncultivated soils will become mandatory in 2025 to comply with NEC 2030´s target of 29 % NH3 reduction relative to 2005. The recent German air pollution control regulation (TA_Luft) enforces abatement measures such as air purifiers in large poultry and pig housings and covered storage of slurry and digestate storages of large farms. The results of the German NH3 abatement strategy for synthetic N fertilizers may help reduce NH3 emissions worldwide, especially for countries consuming high amounts of urea fertilizers.

A survey on the occurrence of papaya ringspot virus-P (PRSV-P) in Malaysia and genetic diversity assessment of the coat protein region.

Papaya ringspot virus (PRSV) is a plant virus transmitted by aphids that has spread throughout many countries, including Malaysia, causing yield losses and economic impacts to the papaya industry worldwide. PRSV infection in papaya-distinctive ring-shaped patterns on papaya leaves resulted in stunted growth and reduced fruit quality. Management strategies such as the use of resistant varieties, cultural practices, and vector control are employed to mitigate the spread of PRSV. However, the evolution of new virus strains and the uncertainties posed by climate change pose ongoing challenges for the management of PRSV worldwide. Therefore, in this present study, we aim to confirm the presence of PRSV in symptomatic papaya leaves, to depict the current status of PRSV in Malaysia. Using reverse-transcription PCR (RT-PCR) targeting PRSV partial nuclear inclusion b protein (NIb) and coat protein (CP), 13 out of 40 papaya leaves collected were found positive for the PRSV strain-P (PRSV-P). Nucleotide analysis revealed a high similarity with strains from Taiwan and India, showing 96.83%, 97.03%, and 97.03% identity with the Taiwan strains (DQ340771, AY027810) and the India strain (KJ755852), respectively. Compared to the CP gene of Malaysian isolates reported in 2016 (EU082207), several nonsynonymous mutations have been discovered suggesting genetic diversity within the PRSV population in Malaysia. Overall, this study confirms the current circulation of PRSV infection in Malaysia since it was first identified in Johore in 1991. The re-occurrence of PRSV-P in this study highlights the need for continuous monitoring and targeted management strategies to prevent the further spread of PRSV-P in Malaysia.

Rice Responses to the Stem Borer Diatraea saccharalis (Lepidoptera: Crambidae) by Infrared-Thermal Imaging: Implications for Field Management

Diatraea saccharalis (Fabricius) is a major pest of rice crops, and its early detection—before any visible plant damage occurs—is crucial to prevent yield losses and establish effective, rational control methods. This study aimed to model the infrared-thermal responses of rice cultivars to D. saccharalis infestation levels. Between 2019 and 2020, two experiments were conducted in a controlled environment using the cultivars IR 40 and BR IRGA 409, previously identified as having different resistance reactions. Rice plants grown in pots were manually infested with first-instar larvae of D. saccharalis, ranging from 0 to 10 caterpillars per plant, with the plants maintained in cages covered with voile fabric throughout the trial. After 30 days of infestation, the number of live and dead caterpillars, the number of damaged and healthy stems, and the dry mass of the aerial parts were evaluated. A generalized linear mixed model was applied to the data obtained from leaf temperature as a function of infestation level throughout the infestation period, using the F-test to detect significant differences between cultivars. Generalized Additive Models for Location, Scale, and Shape (GAMLSS) were fitted to the variables related to resistance. It was observed that leaf surface temperature is related to the level of infestation and could be used to detect susceptibility in IR 40. In both cultivars, leaf temperatures were higher within the first 15 days post-infestation.

Effective weed control through post-emergence herbicides to enhance blackgram (Vigna mungo L.) productivity in South India

Pulses are essential components of vegetarian diet and play a pivotal role in addressing malnutrition by providing a vital source of dietary protein. However, weed competition remains as a significant obstacle to blackgram (Vigna mungo L) production, resulting in 25 to 35% yield losses. A field experiment was carried out at the National Pulses Research Centre, Tamil Nadu Agricultural University, Vamban, Pudukkottai, India during Kharif seasons of 2020 and 2021, to assess the suitable post-emergence herbicides for appropriate weed control in blackgram grown under irrigated conditions. The experimental field was observed to contain notable grass weed flora, specifically Dactyloctenium aegyptium and Chloris barbata, as well as broadleaved weeds, such as Flaveria australica, Cleome gynandra, Eclipta alba, Convolvulus arvensis, Digera arvensis, Vicia spp., and Celosia argentea. The results demonstrated that among the chemical weed management methods, spraying of Fomesafen @ 220 g + Fluzifop p-butyl @ 220 g ha−1 at 20 days after sowing (DAS) as a post-emergence herbicide treatment exhibited superior weed control efficiency, recording 66.80% and 68.53% at 30 and 45 DAS, respectively and recorded higher seed yield of 1088 kg ha−1. Additionally, this method generated 8.1% higher net income and 12.5% more benefit–cost ratio than hand weeding, making it an economically profitable strategy for maximizing blackgram yield and effective labour management.

Bio-Synthesized Fe(0)/Fe2O3 Composite Nanoparticles as a Catalyst towards the Preparation of Dihydropyridine Derivatives under Solvent-Free Condition at Room Temperature

A sustainable and innovative approach has been developed for synthesizing of Fe(0)/Fe2O3 composite nanoparticles (Fe(0)/Fe2O3NPs), utilizing the bark extract of the arjun tree (Terminalia arjuna) as a reducing and capping agent. This environmentally friendly Fe(0)/Fe2O3NPs was thoroughly characterized using various analytical techniques, including UV-Visible spectroscopy, FT-IR, PXRD, HR-TEM, SEM, and XPS. The nanoparticles were then evaluated as catalysts for facilitating the three-component Hantzsch reaction with acetylacetone, ammonium acetate, and substituted aldehydes, producing bioactive dihydropyridine derivatives. The catalyst exhibited high performance over approximately five cycles, with negligible loss in yield and catalytic efficiency. Additionally, a mechanistic pathway was proposed and elucidated through intermediate mass analysis, supported by Density Functional Theory (DFT) calculations.

Projecting impacts of extreme weather events on crop yields using LASSO regression

Extreme weather events are recognized as major drivers of crop yield losses, which threaten food security and farmers’ incomes. Given the increasing frequency and intensity of extreme weather under climate change, it is crucial to quantify the related future yield damages of important crops to inform prospective climate change adaptation planning. In this study, we present a statistical modeling approach to project the changes in crop yields under climate change for eight majorly cultivated field crops in Germany, estimating the impacts of nine types of extreme weather events. To select the most relevant predictors, we apply the least absolute shrinkage and selection operator (LASSO) regression to district-level yield data.The LASSO models select, on average, 62% of the features, which align with well-known biophysical impacts on crops, suggesting that different extremes at various growth stages are relevant for yield prediction. We project on average 2.5-times more severe impacts on summer crops than on winter crops. Under RCP8.5, crop yields experience a mean change from -2.53% to -8.63% in the far future (2069-98) for summer crops and from -0.80% to -2.88% for winter crops, without accounting for CO2 fertilization effects. Heat impacts are identified as the primary driver of yield losses across all crops for 2069-98, while shifting precipitation patterns exacerbate winter and spring waterlogging, and summer and fall drought.Our findings underscore the utility of LASSO regression in identifying relevant drivers for projecting changes in crop yields across multiple crops, crucial for guiding agricultural adaptation. While the present analysis can identify empirical relationships, replicating these findings in biophysical models could provide new insights into the underlying processes.

Agronomic adaptations to heat stress: Sowing summer crops earlier

CONTEXTSummer crops are exposed to heat and drought stresses at critical stages during and after flowering, and their intensity and frequency are likely to increase with climate change. Agronomic stress avoidance offers the opportunity to temporally separate critical crop stages from heat and drought events. However, it might require sowing cold-sensitive summer crops earlier into colder than recommended soil temperatures. There is a need to understand how cold is too cold to sow summer crops early in late winter as well as what are the yield benefits and risks. OBJECTIVEHere, we quantify the likely benefits and trade-offs of sowing sorghum, a summer cereal, earlier to adapt to the increased frequency and intensity of heat and water stresses during flowering and grain filling. METHODSTwo years of multi-environment (n=32) genotype by management trials were conducted across the main sorghum growing regions of Australia. Environments (E) consisted of the combination of years, sites, three times of sowing (early, spring, and summer), and the use of supplementary irrigation. At each E a factorial combination of four plant populations (M) and eight commercial sorghum hybrids (G) were sown with three replications. Crop growth and yield components were measured, and the APSIM model was used to simulate all trials and treatments to quantify risks and derive insights into functional relationships between simulated and measured environmental covariates, and measured crop traits. RESULTSThe tested hybrids showed small differences in cold tolerance during crop establishment. Across the tested environments, the G×M combinations produced up to 60% variation in treatment yields across environment yields, which varied between <0.5 to about 10t ha-1; this translated into a ~5.5-fold variation in water use efficiency. Significant G×E and M×E interactions were observed for grain yield components. No G×M or G×E×M interactions were observed on yield or yield components. Early sowing was associated with a reduced risk of heat stress and water use transfer from vegetative to reproductive stages. Early sowing in late winter or early spring resulted in no significant yield gain or loss when all sites and years were included in the analysis. However, early sowing yielded between 1-2 t ha-1 more when the hottest sites and years were considered separately. This resulted from both the avoidance of heat stresses and milder or no terminal drought stresses. CONCLUSIONSEarly sowing of sorghum can reduce the likelihood of heat stresses around flowering as well as the likelihood of terminal drought stresses. Advantages include reduced yield losses in the hottest years and a transfer of water use to grain filling stages, resulting in increased grain yield and improved grain quality parameters. IMPLICATIONSEarly sowing, an agronomic adaptation, offers the opportunity to quickly adapt to the increase in the frequency and intensity of extreme hot events during critical crop stages. However, for the practice to be de-risked, there is a need to increase cold and chilling tolerance in sorghum and/or identify interventions that enhance seed germination and seedling vigour when the crop is sown early into cold soils.

Effectual Role of Plant Growth-Promoting Fungi and Fosthiazate in Controlling Tomato Root-Knot Nematode Infection: In Vivo and In Vitro Studies

Plant growth-promoting fungi (PGPF) are known to induce systemic resistance in plant diseases caused by microbial pathogens. However, the induced resistance by PGPF has not yet been elucidated in plant diseases caused by root-knot nematodes (RKNs, Meloidogyne spp.). Meloidogyne incognita can severely damage tomato plants, causing considerable losses in world yields. This study aimed to isolate and evaluate the potential of PGPF through enhancing systemic resistance, possibly through activating defense-related pathways in tomato plants, comparing to the commercial chemical nematicide, Melithorin® (fosthiazate 90%). The most potent PGPF (K7, K13, K14) were identified morphologically and molecularly as Alternaria photistica, Penicillium buchwaldii, and Aspergillus niger, respectively. We tested the efficacy of these fungi against RKN (M. incognita) both in vitro and in vivo. The results demonstrated that the commercial nematicide fosthiazate (90%) was the most effective treatment for controlling RKN J2 larvae, achieving a mortality rate of 94% after 96 hours. This was followed by the PGPF treatments, with A. niger at 92.6%, P. buchwaldii at 87.7%, Verticillium lecanii at 73.3%, and A. photistica at 47.4%. Additionally, applying A. photistica, A. niger, P. buchwaldii, and V. lecanii significantly enhanced the levels of photosynthetic pigments, total carbohydrates, and proteins in both healthy and RKN-infected plants. Notably, Melithorin® (fosthiazate 90%), A. niger, and V. lecanii led to substantial increases in root carbohydrate content, with increases of 97%, 63%, and 58%, respectively. Furthermore, Melithorin®, A. photistica, and A. niger significantly boosted shoot protein content by 68%, 65%, and 49%, respectively, compared to the infected control group. These findings indicate that both nematicide and fungal treatments effectively reduce nematode populations and improve overall plant health and nutrient composition. At the same time, the results appeared that infected plants treated with PGPF or Melithorin® showed variation in number and molecular weight of protein bands. SDS-PAGE results indicated that, the highest number of bands (twelve) was recorded in the infected plants treated with Melithorin® followed by P. buchwaldii (11 bands), A. photistica (10 bands), V. lecanii (8 bands), and A. niger (7 bands), respectively. Also, the application of Melithorin®, A. niger, and V. lecanii resulted in a significant increase in the number and weight of fruits, respectively, compared to healthy control plants. Our results suggested that A. photistica, A. niger, P. buchwaldii, and V. lecanii could be used as effective and safe nematicides against RKNs.

Harvesting Light: The Interrelation of Spectrum, Plant Density, Secondary Metabolites, and Cannabis sativa L. Yield

The approaching legalisation and associated increasing demand for medicinal and recreational Cannabis sativa L. will lead to a growing relevance for lighting systems designed for Cannabis sativa L. The interplay between plant density, light spectrum, light distribution, yield, and secondary metabolite distribution within the plant has not yet been studied. To fill this knowledge gap, a CBD-dominant Cannabis sativa L. strain was grown in a greenhouse experiment with two plant densities (2.66 and 12 plants −1 m−2) under two different light spectra. The chosen light spectra were two LED fixtures, Solray385 (SOL) and AP67, with an R: FR ratio of 12.9 and 3.7, respectively. The results indicated that light-induced effects on individual plants can be transferred to the plant stock. A low R: FR ratio induced a 16% increase in dry flower yield in the last ten days of flowering, while a change in the light spectrum could increase the potential maximum plant density per square metre. The two spectra did not affect (CBD + CBDA) yield, as a lower flower yield compensated for a higher concentration. CBDA concentration was not significantly affected by plant density. In contrast, the higher density led to an increased total cannabidiol concentration (CBD + CBDA) and altered the distribution of terpenes. Here, the light distribution over the plant stock is particularly decisive, as a more homogenous illumination led to an increased terpene concentration of up to 41%. A Photon Conversion Efficacy (PCE) of 0.05 g mol−1 under SOL and 0.06 g mol−1 under AP67 was achieved. Plants in the centre under the highest light intensity of 1200 PAR showed up to 48% reduced efficacy. These results strongly suggest that light intensity needs to be fine-tuned to the cultivation system to prevent a reduction in efficacy, resulting in yield and quality losses.

Agricultural innovation for climate change: limited but positive impacts of commercialized drought-tolerant corn

Abstract The extent to which new technologies can countervail the risks posed by climate change is a critical element for designing adaptation strategies. This study uses new experimental data spanning 17 US states from 2008 to 2023 to examine the potential impact of recently commercialized drought tolerant (DT) traits on both yield and yield resilience in US corn production. We find that there is no yield advantage for DT hybrids under average weather conditions, but they improve yield resilience, particularly with respect to precipitation. These effects are spatially heterogeneous, such that DT has a positive yield impact in the droughty, western US, but a small, or even negative, impact in the central and eastern US. In addition, the presence of DT reduces yield variance and kurtosis, and increases skewness, all of which imply a reduction in yield risk. Using the statistical model estimates, we project the impact of DT on corn yields under future climate conditions obtained from 20 general circulation models with two representative concentration pathways. The projected ensemble means of yield gains are 6.34 bu/acre and 5.39 bu/acre under moderate and extreme warming scenarios, respectively, by the mid-twenty-first century. These gains compensate for 23% and 13.5% of total yield loss due to climate change. Our results indicate that current commercial DT hybrids reduce yield risk, improve resilience with respect to precipitation, and have the potential to offer moderate benefits under climate change warming scenarios.

Mycotoxigenic Fusarium species and zearalenone concentration in commercial maize kernels in northern Ghana.

The fungal genus Fusarium contains many toxigenic pathogens of maize with associated yield losses, reduction of grain quality, and accumulation of mycotoxins in harvested grains. To determine zearalenone (ZEN) concentration and identify the various Fusarium species in commercial maize grains, a survey of 75 maize samples, collected from 11 market centers in the five regions in northern Ghana was identified based on morphological characteristics, sequence analysis of the internal transcribed spacer region, and polymerase chain reaction using species-specific primers. ZEN levels were determined using HPLC. ZEN contamination was recorded in 33.3% of the maize samples, with concentrations ranging from 0.61 to 3.05µg/kg. Based on VERT1/2 and TEF 1-α sequencing, F. verticillioides was the most prevalent species in the studied samples: 40.35% from the Upper East Region, 28.07% from the North East Region, 19.30% from the Upper West Region, 10.53% from the Savannah Region, and 1.75% for the Northern Region. Other fungal species found were F. equiseti and F. solani. A higher number of the Fusarium isolates were found in white maize (609 isolates from 27 samples) compared to yellow maize (225 isolates from 23 samples).

Optimization of border irrigation variables based on a correction factor for irrigation quota

The optimization of surface irrigation variables, i.e., the selection of the optimal combination of the inflow rate per unit width (q) and cutoff time (tco), is essential for obtaining high performance. The main objective of this study was to optimize irrigation variables by considering different irrigation requirements and the total loss model, which includes the irrigation water loss and crop yield loss. A correction factor for the irrigation quota (Cf) was introduced to achieve this objective. Cf considers different irrigation requirements, as it represents the ratio of the actual irrigation quota for certain irrigation to the designed irrigation quota (Dreq). Uniform design theory was used to determine random combinations of q and Cf from a selected range. The q value ranged from 3 to 9 L.m-1. s-1. Because the actual irrigation quota does not greatly deviate from the design irrigation quota, Cf should reach approximately 1.00. The selected Cf ranged from 0.80 to 1.38. To obtain higher crop yields, lower economic losses, and more reasonable design variables for surface irrigation, a total loss model for uneven border irrigation was established, which was defined as the objective function to optimize border irrigation design—the total loss model was combined with uniform design theory and the WinSRFR model to analyze different scenarios. The results showed that Cf has a clear meaning and exerts a favorable application effect on the irrigation performance evaluation indicators and can be used to design border irrigation systems. Based on the total loss model for uneven border irrigation, the optimal irrigation variables q and Cf for design irrigation quotas of 60, 80, and 100 mm are q=6.22 L.m-1. s-1 and Cf=1.17; q=4.60 L.m-1. s-1 and Cf=1.14; and q=3.80 L.m-1. s-1 and Cf=1.10, respectively. Compared with the conventional design results, q in the optimal design results based on the loss model decreased, Cf increased, and the total loss significantly decreased. Optimization of irrigation variables based on the border irrigation loss model could ensure favorable irrigation performance evaluation indicators, improve the water use efficiency, provide higher crop yields, and minimize the total economic losses caused by uneven irrigation.

Factors Associated With Missing Biological Samples in the Dog Ageing Project.

The Dog Aging Project (DAP) is a longitudinal study examining aging in US companion dogs, where missing data pose a challenge to result validity and statistical power. Early recognition and procedural adjustments are vital to address missing samples. This research assesses missing biospecimen samples within the PRECISION cohort of the DAP, aiming to identify contributing factors and propose mitigation strategies. Ninety sample kits collected between August 2021 and October 2021 were evaluated for the missingness of individual kit components. A primary assessment reviewed the missingness of each sample type with hypothesized associated factors. A secondary assessment addressed the missingness of plasma and serum aliquots made after check-in. EDTA samples for flow cytometry, peripheral blood mononuclear cells (PBMCs), DNA and biobanking were missing at rates of 18.9%, 13.3%, 6.7% and 5.6%, respectively. Faecal samples were missing at 5.6%. Urine and plasma were each missing at 2.2%. Serum, hair and dried blood spot cards were each missing at 1.1%. No statistically significant difference in missingness was seen across regions, ease of blood collection, or cooperativeness of dog during sample collection. Higher time-to-receipt was associated with a higher missingness proportion. Increasing missingness proportions were seen across plasma and serum aliquots that were created in sequential order. The study suggests reevaluating sample collection instructions to address frequently missing sample types and prevent further loss. Investigation into collection procedures for these types is recommended to identify potential causes of sample yield loss.

Population structure and markers analysis associated with powdery mildew resistance in pumpkin, Cucurbita pepo L

Pumpkin (Cucurbita pepo L.) is an economically important vegetable and summer crop. The seeds have high nutritional value due to their edible oil and protein content with a high medicinal value. Pumpkin is attacked by several fungal diseases; one of which is powdery mildew (PM) caused by Podosphaera xanthii race-0. PM causes severe disease on pumpkin leading to major yield losses globally. In this study, we analyzed the genetic diversity and population structure of fourteen local pumpkin cultivars, all under Cucurbita pepo L. based on dominance in the region using 15 Inter-Simple-Sequence-Repeats-(ISSR) primer-pairs in association with resistance against PM as well as regulating the expression of three resistant marker genes i.e. SGT1, bHLH and PSK via qRT-PCR at three stages with 10 days' interval post-inoculation-stages-(SPI) with the powdery mildew agent, P. xanthii race-0. The results showed that ISSR markers demonstrated 13 primers out of 15 primers generated 169 distinct amplified bands, out of which 143 bands showed polymorphism. The mean polymorphism information content (PIC), marker index (MI), effective-number of alleles (I), expected heterozygosity (H), and Nei's gene diversity parameters were 0.354, 3.344, 0.334, 0.205 and 0.200, respectively. According to PIC, MI, I, H, and Nei indices evaluation, ISSR10 primer had the best performance in genetic diversity of the related pumpkin population. NTSYS pc 2.02e software and several similarity coefficients (r = 0.964), placed the related genotypes into five distinct groups. Of which, ‘Maragheh1′ and ‘Shahreza’ as resistant ones with 9.4 % and 6.1 % disease severity (DS), and ‘Gorgan’, ‘Urmia1′ and 3 and ‘Maragheh3’ with 79.6–84.8 % DS, as susceptible ones into two distinct groups, respectively. Further, the marker genes SGT1, bHLH and PSK expression level changes showed that the effect of variable factors including different genotypes (susceptible and resistant), disease-causing fungus, SPI, and the mutual effect of these factors is significant with the highest increase in resistant genotypes. Considering the relative compatibility in the classification of pumpkin genotypes in the dendrograms of DS and ISSR markers, it can be expected that increasing the number of markers in evaluating the genetic diversity of these genotypes makes it possible to differentiate pumpkin genotypes resistant and susceptible to PM disease based on the degree of disease resistance. The markers associated with resistance are recommended for use in marker assisted breeding.

Systematical characterization of Rab7 gene family in Gossypium and potential functions of GhRab7B3-A gene in drought tolerance

BackgroundCotton serves as a primary source of natural fibers crucial for the textile industry. However, environmental elements such as drought have posed challenges to cotton cultivation, resulting in adverse impacts on both production and fiber quality. Improving cotton’s resilience to drought could mitigate yield losses and foster the expansion of cotton farming. Rab7 protein, widely present in organisms, controls the degradation and recycling of cargo, and has a potential role in biotic and abiotic tolerance. However, comprehensive exploration of the Rab7 gene family in Gossypium remains scarce.ResultsHerein, we identified a total of 10, 10, 20, and 20 Rab7 genes through genome-wide analysis in Gossypium arboreum, Gossypium raimondii, Gossypium hirsutum, and Gossypium barbadense, respectively. Collinearity analysis unveiled the pivotal role of whole genome or segmental duplication events in the expansion of GhRab7s. Study of gene architecture, conserved protein motifs, and domains suggested the conservation of structure and function throughout evolution. Exploration of cis-regulatory elements revealed the responsiveness of GhRab7 genes to abiotic stress, corroborated by transcriptome analysis under diverse environmental stresses. Notably, the greatly induced expression of GhRab7B3-A under drought treatment prompted us to investigate its function through virus-induced gene silencing (VIGS) assays. Silencing GhRab7B3-A led to exacerbated dehydration and wilting compared with the control. Additionally, inhibition of stomatal closure, antioxidant enzyme activities and expression patterns of genes responsive to abiotic stress were observed in GhRab7B3-A silenced plants.ConclusionsThis study sheds light on Rab7 members in cotton, identifies a gene linked to drought stress, and paves the way for additional investigation of Rab7 genes associated with drought stress tolerance.

Weed dynamics, energetic, yields and economics as influenced by sequential application of herbicides for weed management in direct seeded rice

This study quantifies the crop yield loss by weeds and management of hardy and prominent weeds. Uncontrolled weeds reduced grain yield of DSR by 68%. Pendimethalin 1.0 kg ha−1 pre-emergence (PE) followed by (fb) bispirbac-sodium 30 g ha−1 at 25 DAS fb fenoxaprop-p-ethyl 60 g ha−1 at 30 DAS, and pendimethalin 1.0 kg ha−1 (PE) fb azimsulfuron 25 g ha−1+fenoxaprop-p-ethyl 60 g ha−1 at 30 DAS significantly reduced weed density and weed dry matter, and recorded higher grain yield in DSR than other treatments. The pendimethalin 1.0 kg ha−1 (PE) fb bispyribac-sodium 30 g ha−1 at 30 DAS was statistically similar to stale seed-bed fb bispyribac-sodium 30 g ha−1 at 30 DAS and gave higher weed control efficiency and energy index compared to unweeded control and bispyribac-sodium 30 g ha−1 at 30 DAS. Pendimethalin 1.0 kg ha−1 (PE) fb bispyribac-sodium 30 g ha−1 at 25 DAS fb fenoxaprop-p-ethyl 60 g ha−1 30 DAS showed more promising in controlling tough weeds like L. chinensis and D. aegyptium and predominant weeds (Echinochloa colona, broad-leaved weeds and Cyperus species) in DSR.

The landscape of sequence variations between resistant and susceptible hot peppers to predict functional candidate genes against bacterial wilt disease

BackgroundBacterial wilt (BW), caused by Ralstonia solanacearum (Ral), results in substantial yield losses in pepper crops. Developing resistant pepper varieties through breeding is the most effective strategy for managing BW. To achieve this, a thorough understanding of the genetic information connected with resistance traits is essential. Despite identifying three major QTLs for bacterial wilt resistance in pepper, Bw1 on chromosome 8, qRRs-10.1 on chromosome 10, and pBWR-1 on chromosome 1, the genetic information of related BW pepper varieties has not been sufficiently studied. Here, we resequenced two pepper inbred lines, C. annuum ‘MC4’ (resistant) and C. annuum ‘Subicho’ (susceptible), and analyzed genomic variations through SNPs and Indels to identify candidate genes for BW resistance.ResultsAn average of 139.5 Gb was generated among the two cultivars, with coverage ranging from 44.94X to 46.13X. A total of 8,815,889 SNPs was obtained between ‘MC4’ and ‘Subicho’. Among them, 31,190 (0.35%) were non-synonymous SNPs (nsSNPs) corresponding to 10,926 genes, and these genes were assigned to 142 Gene Ontology (GO) terms across the two cultivars. We focused on three known BW QTL regions by identifying genes with sequence variants through gene set enrichment analysis and securing those belonging to high significant GO terms. Additionally, we found 310 NLR genes with nsSNP variants between ‘MC4’ (R) and ‘Subicho’ (S) within these regions. Also, we performed an Indel analysis on these genes. By integrating all this data, we identified eight candidate BW resistance genes, including two NLR genes with nsSNPs variations in qRRs-10.1 on chromosome 10.ConclusionWe identified genomic variations in the form of SNPs and Indels by re-sequencing two pepper cultivars with contrasting traits for bacterial wilt. Specifically, the four genes associated with pBWR-1 and Bw1 that exhibit both nsSNP and Indel variations simultaneously in ‘Subicho’, along with the two NLR genes linked to qRRs-10.1, which are known for their direct involvement in immune responses, are identified as most likely BW resistance genes. These variants in leading candidate genes associated with BW resistance can be used as important markers for breeding pepper varieties.

Cannibalism in Spodoptera frugiperda larvae: Effects of food lack, host plants, and food distribution

The fall armyworm, Spodoptera frugiperda, is a highly polyphagous agricultural pest widely distributed around the world and causes severe crop yield loss. As a common phenomenon in many insects, cannibalism is also observed in the larvae of S. frugiperda. While the factors that affect this phenomenon in S. frugipreda larvae remain unclear and not quite systematic. In this study, the effects of three factors, including a lack of food supply, different host plants, and variation in food distribution, on the cannibalism of larvae from the third, fourth, and fifth instars of S. frugipreda were investigated. Our results suggest that a longer time without food supply, a non-preferred host plant, and simple food distribution could increase cannibalism. Our results not only provide critical information for the mass rearing of S. frugiperda larvae, but also offer preliminary support for further study on the mechanism of cannibalism in this pest.