Aflatoxin Contamination In Peanuts Research Articles

Preharvest insect pests of peanuts and associated aflatoxin contaminants in Georgia, USA.

On-farm losses of peanuts (Arachis hypogaea L.,Fabales: Fabaceae) pose a persistent threat to the sustainable production and value of peanuts in the United States. This study presents empirical data on the spatial distribution of subterranean insect pests and various quality aspects of peanuts. Surveys were conducted in 20 randomly selected peanut fields in 10 counties in Northeast, Southeast, and Southwest Georgia. The primary insect pests found in Georgia's peanut production counties were Pangaeus bilineatus (Say), Elasmopalpus lignosellus (Zeller), and Diabrotica undecimpunctata Howardi. In the northeast counties, a high prevalence of P. bilineatus led to a significant increase in insect-damaged pods (%IDP), insect-damaged kernels (%IDK), discolored kernels (%DK), pod weight loss (%PWL), and kernel weight loss (%KWL). Similarly, southeast counties had a high %DK, cracked pods (%CP), and E. lignosellus infestation. In southwest counties, predominantly high D. undecimpunctata infestations resulted in the highest %IDP. Moisture content (%MC) was excessively high in all the counties (22.19%-23.17%). Preharvest aflatoxin contamination in peanuts was prevalent across all studied locations, particularly in counties with a high incidence of P. bilineatus and may cause increased risk in aflatoxin levels along the supply chain. Nevertheless, the diverse regional abundance of insect pests and the widespread presence of aflatoxins in Georgia's peanut fields offer valuable insights for developing integrated pest management strategies targeting subterranean insect pests. This is especially crucial in addressing the impact of P. bilineatus, E. lignosellus, and D. undecimpunctata on aflatoxins content of peanuts and determining the pathway for mitigation of aflatoxin contaminations in peanuts at harvest.

Impact of conservation farming practices on Aspergillus population density, peanut aflatoxin level, and exposure risk in Zambia

Aflatoxin contamination in peanuts (Arachis hypogaea L.) by aflatoxin-producing Aspergillus spp. is a serious problem worldwide affecting human health and restricting trade. Recently, conservation agriculture practices such as minimum tillage, crop rotation, soil surface cover, intercropping, and planting in basins alongside trees that enhance soil fertility, have been introduced in Zambia as tools to conserve soil moisture, increase peanut yield, and reduce the risk of aflatoxin contamination. However, a limited understanding exists of the impact of conservation agriculture on Aspergillus population densities in the soil and aflatoxin concentrations in crops grown under conservation agriculture. This study assessed the impact of conservation agriculture on (i) Aspergillus communities profile in soil cropped to peanuts, (ii) peanut aflatoxin contamination levels, and (iii) influences of the practices on liver cancer risks as a result of consuming peanuts grown in basins, peanuts grown in basins in farms having Gliricidia sepium trees (agroforestry), and peanuts grown on ridges (conventional tillage). Densities of Aspergillus spp. in soils ranged from 10 to 7,400 CFU/g (mean = 295 CFU/g). The densities differed among farming techniques (p = 0.0011) with conventional tillage (357 CFU/g) supporting higher densities than agroforestry (296 CFU/g) and peanuts grown in basins (230 CFU/g). Aspergillus communities were dominated by fungi with S morphology (55%; which is composed of several morphologically similar species), followed by A. parasiticus (34%), and the L morphotype of A. flavus (11%). Over 60% of the peanut samples were contaminated but there were no differences among farming techniques. Mean aflatoxin contents in peanuts were 110, 99, and 87, μg/kg for agroforestry, conventional tillage, and peanuts grown in basins, respectively. Probable daily aflatoxin intake ranged from 12.7 to 767.1 ng/kg body weight/d, depending on the age of consumers. The estimated liver cancer risk due to consumption of raw peanuts (0.334 to 20.128 cases/100,000 persons/year) was highest among children below 5 years and least for young adults. The results showed that growing peanuts in basins has the potential to reduce Aspergillus populations in soil. Possibly, planting in basins and agroforestry had minimal effect on water runoff and did not support sufficient moisture retention in the soil to reduce Aspergillus spp. densities and aflatoxin accumulation in the peanuts. Thus, more research is needed to improve the effectiveness of peanut cultivation in basins in shaping the Aspergillus species profiles for ultimately reducing aflatoxin in peanuts to safe levels. Given the high exposure of Zambia’s population, especially children, and that contaminated food is the major source of exposure, it is essential that appropriate technical, policy and institutional measures are promoted for aflatoxin mitigation in Zambia.

Genomic Selection as an Approach to Select for Reduced Aflatoxin Contamination in Peanut Under Terminal Drought Stress

Pre-harvest aflatoxin contamination (PAC) occurs when the peanut is exposed to severe drought and heat stress prior to harvest. Development of genotypes that are either resistant or limiting to Aspergillus infection and/or that can curtail aflatoxin production is a key objective in peanut breeding. Using SNP markers and phenotype data on aflatoxin resistance collected in previous years, we utilized genomic selection (GS) to study PAC resistance in peanut. The technique was validated in the Florida-07 x GP-NC WS 16 recombinant inbred population by assessing high heritability traits. GS was then deployed to study PAC resistance in the Tifrunner x C76-16 and Florida-07 x C76-16 populations. The resultant models yielded prediction accuracy values of 0.24 and 0.23 which while low, were comparable to the heritability values of 0.31 and 0.1 for each population, respectively. Using genomic estimated breeding values (GEBVs), entries were selected for two drought shelter studies. Manual scoring and multispectral imaging were used to acquire end season drought stress data. Low correlation values (-0.15 for shelter A and 0.32 for shelter B) were observed between the GEBVs and actual end season aflatoxin content. Correlations between visual drought ratings and PAC were also low (0.23 and 0.16 for shelter A and B respectively). While strong inverse correlations were observed between GNDVI and visual drought ratings (-0.74 and -0.73 for shelters A and B respectively), GNDVI did not confer a clear advantage for selection of PAC resistance. Ideally, the use of genome-spanning markers in GS may enable selection for a difficult to phenotype trait like PAC resistance. Although this study did not show clear advantages of the method over conventional selection, it is an important step for implementation of GS and the use of GEBVs for trait selection in peanut.

EXPLORING THE IMPACT OF SOIL AMENDMENTS ON FOOD SAFETY AND CROP PRODUCTIVITY FOR SUSTAINABLE AGRICULTURE

Aflatoxins impact the entire food supply chain, from agricultural fields to processing facilities, markets, and consumer tables. In peanut cultivation, this threat poses a constant challenge throughout the cultivation, processing, and consumption stages. To confront this challenge, an exhaustive study was undertaken with the aim of investigating the effects of targeted soil amendments; namely, Vermicompost, Lentil crop residue, and Sulphate of Potash applied during the pivotal sowing phase at two distinct locations, Chakwal and Attock. The research includes meticulous groundnut sample analysis to quantify aflatoxin levels, revealing a significant reduction across all soil amendments compared to the control group. Vermicompost stands out as the most effective, achieving a remarkable 64.8% reduction, followed closely by Sulphate of Potash at 62.4%. Statistical analysis highlights non-significant differences among amendments. Beyond aflatoxin mitigation, the study underscores the dual benefit of these soil amendments, contributing not only to mycotoxin control but also enhancing overall crop productivity. Percent increase in number of grains per plant ranged between 58.82% to 43.53% whereas in hundred grain weight it ranged between 17.10% and 10.55%. In summary, the study emphasizes the importance of strategic soil amendments, particularly Vermicompost and Sulphate of Potash, in mitigating aflatoxin contamination in peanuts. The dual benefit of improved crop productivity adds significance to the findings, offering a holistic approach to address the multifaceted dimensions of aflatoxin challenges in peanut cultivation.

Evaluation of the Level of Aflatoxins in Raw Peanuts and Reduction Levels of Aflatoxins in Peanuts through Nixtamalization (Lime Treatment) and Calcium Enrichment

Nixtamalization has been widely used as a method of reducing aflatoxin contamination in peanuts as well as in calcium enrichment. The aim of this study is to investigate the effects of nixtamalization on aflatoxin and nutrient content in peanuts among wholesalers and retailers at Nyamakima Market in Nairobi, Kenya. A representative sample was drawn from a population of 70 market vendors using a systematic random sampling technique, resulting in 35 raw peanut samples for analysis via ELISA to determine initial aflatoxin levels. These samples were then subjected to nixtamalization treatments of 4, 8, and 16 minutes. The findings revealed that the average concentration of total aflatoxins in peanuts initially exceeded the accepted safety limit, with 71% of the samples failing to meet the standards. However, nixtamalization led to a substantial reduction in aflatoxin levels by 49%, 48%, and 50% after treatment durations of 4, 8, and 16 minutes, respectively. Statistical analysis, including ANOVA and Two-sample T-tests, confirmed significant distinctions between initial and final mean aflatoxin levels post-treatment, as well as variations between treatments. The study also observed a significant variation in calcium levels between the different time treatments, supported by linear regression analysis, which demonstrated a robust correlation between time treatments and calcium levels (R2=0.83, P=0.011). Furthermore, the analysis revealed significant differences in mean moisture contents across various treatments (P=0.000), and a linear relationship between mean moisture content and exposure time (P=0.02). The results emphasize the positive impact of nixtamalization in reducing aflatoxin levels and enhancing calcium content in peanuts. However, it is crucial to note the negative effect on moisture content, which exceeded stipulated limits, potentially raising concerns about product safety and quality.

Geographical distribution of Aspergillus flavus in peanut harvest period in China

In order to grasp the distribution of Aspergillus flavus in the soil of peanut production areas in China, A. flavus biomarkers were tested on 555 soil samples from 37 sampling points in 17 provinces, peanut fields in four agroecological zones (Southern area, Yangtze River Basin, Northern area, Northeast area). The results showed that (1) the cultivation amount of A. flavus per gram of soil in the Yangtze River Basin is 1.30 times that of the southern area, 1.56 times that of the northern area, and 6.20 times that of the northeast area, with obvious regional characteristics. (2) In the Yangtze River basin, the change of longitude in the east-west direction has no direct impact on the cultivation amount of A. flavus per gram of soil. (3) In the east coast, the A. flavus cultivated per gram of soil increased first and then decreased with the increase of latitude from south to north. (4) A. flavus can be isolated in the soil samples above 1000 ​m. Field pollution is an important source of aflatoxin contamination in peanut. The study on the distribution of A. flavus in soil in China could provide theoretical support for the early warning and prevention and control measures of aflatoxin contamination in peanut.

Evaluation of Reduction of Aflatoxins by Near Infrared Spectrometric Sorting In the Highly Aflatoxin-Contaminated Peanut Lots

Evaluation of Reduction of Aflatoxins by Near Infrared Spectrometric Sorting In the Highly Aflatoxin-Contaminated Peanut Lots

Application of Non-Aflatoxigenic Aspergillus flavus for the Biological Control of Aflatoxin Contamination in China.

Biological control through the application of competitive non-aflatoxigenic Aspergillus flavus (A. flavus) to the soil during peanut growth is a practical method for controlling aflatoxin contamination. However, appropriate materials need to be found to reduce the cost of biocontrol products. In this study, a two-year experiment was conducted under field conditions in China, using a native non-aflatoxigenic strain to explore its effect. After three months of storage under high humidity, aflatoxin levels remained low in peanuts from fields treated with the biocontrol agent. Three types of substrates were tested with the biocontrol agent: rice grains, peanut meal (peanut meal fertilizer) and peanut coating. Compared to untreated fields, these formulations resulted in reductions of 78.23%, 67.54% and 38.48%, respectively. Furthermore, the ratios of non-aflatoxigenic A. flavus recovered in the soils at harvest in the treated fields were between 41.11% and 96.67% higher than that in untreated fields (25.00%), indicating that the rice inoculum was the most effective, followed by the peanut meal fertilizer and peanut coating. In 2019, the mean aflatoxin content of freshly harvested peanuts in untreated fields was 19.35 µg/kg higher than that in the fields treated with 7.5 kg/ha rice inoculum, which was 1.37 µg/kg. Moreover, no aflatoxin was detected in the two other plots treated with 10 and 15 kg/ha rice inoculum. This study showed that the native Chinese non-aflatoxigenic strain of A. flavus (18PAsp-zy1) had the potential to reduce aflatoxin contamination in peanuts. In addition, peanut meal can be used as an alternative substrate to replace traditional grains, reducing the cost of biocontrol products.

Prevalence of Aflatoxin Contamination in Peanuts and Peanut Butter from an Informal Market, Harare, Zimbabwe.

Peanuts and peanut butter play an important role nutritionally in improving the diets of individuals in many parts of Africa, especially in the fight against child malnutrition. However, in developing countries such as Zimbabwe, most of the raw peanuts and peanut butter produced in backyard industries are sold in informal markets and rarely undergo formal safety inspection for aflatoxin contamination. The objective of the study was to determine the prevalence of aflatoxins in raw peanuts and backyard peanut butter sold at Mbare informal market. Ten (10) raw peanut samples and twenty (20) peanut butter samples were collected from Mbare informal market. Aflatoxin contamination was determined using liquid chromatography-mass spectrometry (LC-MS). The results revealed that sixty percent (60%) of the raw peanut samples were contaminated with total aflatoxin ranging from <0.75 to 426.4 μg/kg. One hundred percent (100%) of peanut butter samples were contaminated with total aflatoxins ranging from 4.7 μg/kg to 435.0 μg/kg. Aflatoxin B1 was the most prevalent aflatoxin in both raw peanuts (range, 1.2 μg/kg to 90.8 μg/kg) and peanut butter (range, 4.7 to 382.9 μg/kg). Forty percent (40%) of the raw peanuts and 95% of peanut butter samples exceeded the maximum limits of AFB1 as set by Zimbabwe legislation. The results suggest that raw peanuts and especially the peanut butter from backyard industries are heavily contaminated with aflatoxins and could constitute a possible health risk to consumers who regularly purchase these food commodities from informal markets.

Biocontrol efficacy of atoxigenic Aspergillus flavus strains against aflatoxin contamination in peanut field in Guangdong province, South China

ABSTRACT Application of atoxigenic strains of Aspergillus flavusto soils is the most successful aflatoxin biological control approach. The objective of this study was to evaluate the efficacies of native non-aflatoxin producing (atoxigenic) strains as a biocontrol agent in peanut field in China. The competitive atoxigenic A. flavus strains (JS4, SI1and SXN) isolated from different crops, in China were used for field evaluation. The strains applied during the growing season (June – October, 2016) in the field at rate of 25 kg inoculum/hectare. The colonization of these biocontrol agents has been investigated and the population of A. flavus communities in soil were determined. The incidences of toxin producing (toxigenic) A. flavus strains and aflatoxin contamination in peanuts were also determined. Treated plots produced significant reductions in the incidence of toxigenic isolates of A. flavus in soil. However, the total fungal densities were not significantly different (p > 0.05) after treatments. Large percentage of aflatoxin reductions, ranging from 82.8% (SXN) up to 87.2% (JS4) were recorded in treated plots. Generally, the results suggest that the strategy can be used to control aflatoxin contamination and continuous evaluation should be done.

Detection of Aflatoxin B1 in Peanut Oil Using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy Combined with Partial Least Squares Discriminant Analysis and Support Vector Machine Models

This study was conducted to establish a rapid and accurate method for identifying aflatoxin contamination in peanut oil. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy combined with either partial least squares discriminant analysis (PLS-DA) or a support vector machine (SVM) algorithm were used to construct discriminative models for distinguishing between uncontaminated and aflatoxin-contaminated peanut oil. Peanut oil samples containing various concentrations of aflatoxin B1 were examined with an ATR-FTIR spectrometer. Preprocessed spectral data were input to PLS-DA and SVM algorithms to construct discriminative models for aflatoxin contamination in peanut oil. SVM penalty and kernel function parameters were optimized using grid search, a genetic algorithm, and particle swarm optimization. The PLS-DA model established using spectral data had an accuracy of 94.64% and better discrimination than did models established based on preprocessed data. The SVM model established after data normalization and grid search optimization with a penalty parameter of 16 and a kernel function parameter of 0.0359 had the best discrimination, with 98.2143% accuracy. The discriminative models for aflatoxin contamination in peanut oil established by combining ATR-FTIR spectral data and nonlinear SVM algorithm were superior to the linear PLS-DA models.

Evaluation of reduction of aflatoxins by near infrared spectrometric sorting in the highly aflatoxin-contaminated peanut lots

Peanuts are one of the most susceptible crops to aflatoxigenic fungi, such as Aspergillus flavus and Aspergillus parasiticus, and is often contaminated with aflatoxins (AFs). AF contamination of peanuts is a major human and animal health hazard that has an economic impact worldwide. Numerous control and management strategies have been developed to reduce the levels of AFs in peanuts and sorting is the final stage in the process targeted at decreasing AF levels. Previous studies have shown that handpicking and electric color sorting are not entirely effective in reducing AF levels because of the occurrence of apparently healthy but internally moldy kernels with high AF levels. A previous study (Hirano, et al. 1998) showed that near infrared (NIR), the ratio of transmittance energies at two wavelengths of 700 to 1100, was applicable for efficiently removing internally moldy kernels. However the use of this procedure was limited to a sample that contained artificially inoculated kernels and low levels of AFs. This present study evaluated the performance of spectrometric sorting in naturally and highly AF-contaminated peanut lots on a commercial scale. The NIR spectrometric sorting clearly showed that AFs could be effectively decreased to levels of < 10 μg/kg even when the lot was highly contaminated with > 700 μg/kg of AFs by rejecting deteriorated kennels, including those that were internally moldy.

Effect of non-aflatoxigenic strains of Aspergillus flavus on aflatoxin contamination of pre-harvest peanuts in fields in China

Aflatoxin contamination of peanuts is one of the most concerns in peanut production in China. Applying non-aflatoxigenic Aspergillus flavus strains, based on competitive exclusion, has been proved to be a promising strategy to reduce aflatoxin contamination in pre-harvest peanuts. Two non-aflatoxigenic A. flavus strains collected in China, which have been proved effectively reducing aflatoxin in the laboratory, were mixed with high aflatoxin producer to the soil in peanut growing season. The two non-aflatoxigenic strains significantly (P ​< ​0.05) reduced aflatoxin contamination in peanut kernels under both normal and drought stresses in two fields. Compared to control, the total aflatoxin (sum of aflatoxin B1 and B2) was reduced 26.7–99.12% in field 1, and 84.96–99.33% in field 2. The aflatoxin was reduced 84.96–99.33% under drought stress in two fields. The present study indicated the non-aflatoxigenic A. flavus strains could be potential biocontrol agents for reducing aflatoxin contamination under field condition.

The Relationship Between Aspergillus flavus in Peanut Soil and Aflatoxin Contamination of Peanut in China

The Relationship Between Aspergillus flavus in Peanut Soil and Aflatoxin Contamination of Peanut in China

Evaluation of Agricultural Practices to Increase Yield and Financial Return and Minimize Aflatoxin Contamination in Peanut in Northern Ghana

ABSTRACTPeanut (Arachis hypogaea L.) yield and financial returns are often low for smallholder farmers in Ghana. Additionally, aflatoxin concentration in foods derived from peanut can be high enough to adversely affect human health. Eight experiments were conducted in 2016 and 2017 in northern Ghana to compare yield, financial returns, pest reaction, and aflatoxin contamination at harvest with traditional farmer versus improved practices. Relative to the farmer practice, the improved practice consisted of weeding one extra time, applying local potassium-based soaps to suppress arthropods and pathogens, and application of either homogenized oyster shells or a commercial blend of fertilizer containing calcium. Each of these field treatments were followed by either drying peanut on the soil surface and storing in traditional poly bags or drying peanut on tarps and storing in hermetically-sealed bags for 4 months. Peanut yield and financial returns were significantly greater when a commercial blend of fertilizer or oyster shells were applied compared to the farmer practice of not applying any fertilizer. Yield and financial returns were greater when a commercial fertilizer blend was applied compared with oyster shells. Severity of early leaf spot [caused by Passalora arachidicola (Hori) U. Braun] and late leaf spot [caused by Nothopassalora personata (Berk. &amp; M.A. Curtis) U. Braun, C. Nakash., Videira &amp; Crous], scarring and penetration of pods by arthropods, and the number of arthropods at harvest were higher for the farmer practice than for either fertility treatment; no difference was noted when comparing across fertility treatments. Less aflatoxin was observed for both improved practices in the field compared with the farmer practice. Drying peanut on tarps resulted in less aflatoxin compared to drying peanut on the ground regardless of treatments in the field. Aflatoxin concentration after storage was similar when comparing post-harvest treatments of drying on soil surface and storing in poly bags vs. drying on tarps and storing in hermetically-sealed bags. These results demonstrate that substantial financial gain can be realized when management in the field is increased compared with the traditional farmer practice. While aflatoxin concentrations differed between the farmer practice and the improved practices at harvest and after drying, these differences did not translate into differences after storage.

Minimizing Aflatoxin Contamination in the Field, During Drying, and in Storage in Ghana

ABSTRACT Aflatoxin in peanut (Arachis hypogaea L.) and other crops can negatively affect human health, especially in countries where regulatory agencies do not have limits on aflatoxin entering the food supply chain. While considerable research has been conducted addressing aflatoxin contamination in peanut at individual steps in the supply chain, studies that quantify aflatoxin contamination following combinations of interventions to crop management, drying, and storage are limited. Research was conducted during 2016 and 2017 in two villages in southern Ghana to follow aflatoxin contamination along the supply chain and to compare improved practices with traditional farmer practices used by smallholders. The farmer practice of only a single weeding was compared with improved practices during the growing season up to harvest that included applying local soaps to suppress aphids (Aphis gossypii Golver) that transmit peanut rosette virus disease (Umbravirus: Tombusviridaee), one additional weeding, and calcium applied at pegging. The improved practice for drying included placing pods removed from plants onto tarps compared with the traditional practice of drying on the ground. Storing peanut for four months in hermetically-sealed bags was the improved practice compared with storing in traditional poly bags. All improved practices individually resulted in lower aflatoxin contamination as compared to the farmer practices. While aflatoxin levels were very low (&amp;lt;1 μg/kg) at harvest, the levels increased significantly during drying and storage, with the improved methods resulting in lower levels. Greater estimated financial returns were noted when at least one improved practice along the supply chain was implemented through either increased yield or maintenance of quality kernels. Results from this research demonstrate progression of aflatoxin contamination at pre- and especially post-harvest in villages in Ghana. Future research needs to consider the effects of improved practices as components of packages that farmers can consider, and not just as individual interventions.

Integrated small RNA and mRNA expression profiles reveal miRNAs and their target genes in response to Aspergillus flavus growth in peanut seeds

BackgroundMicroRNAs are important gene expression regulators in plants immune system. Aspergillus flavus is the most common causal agents of aflatoxin contamination in peanuts, but information on the function of miRNA in peanut-A. flavus interaction is lacking. In this study, the resistant cultivar (GT-C20) and susceptible cultivar (Tifrunner) were used to investigate regulatory roles of miRNAs in response to A. flavus growth.ResultsA total of 30 miRNAs, 447 genes and 21 potential miRNA/mRNA pairs were differentially expressed significantly when treated with A. flavus. A total of 62 miRNAs, 451 genes and 44 potential miRNA/mRNA pairs exhibited differential expression profiles between two peanut varieties. Gene Ontology (GO) analysis showed that metabolic-process related GO terms were enriched. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses further supported the GO results, in which many enriched pathways were related with biosynthesis and metabolism, such as biosynthesis of secondary metabolites and metabolic pathways. Correlation analysis of small RNA, transcriptome and degradome indicated that miR156/SPL pairs might regulate the accumulation of flavonoids in resistant and susceptible genotypes. The miR482/2118 family might regulate NBS-LRR gene which had the higher expression level in resistant genotype. These results provided useful information for further understanding the roles of miR156/157/SPL and miR482/2118/NBS-LRR pairs.ConclusionsIntegration analysis of the transcriptome, miRNAome and degradome of resistant and susceptible peanut varieties were performed in this study. The knowledge gained will help to understand the roles of miRNAs of peanut in response to A. flavus.

High-density SNP map facilitates fine mapping of QTLs and candidate genes discovery for Aspergillus flavus resistance in peanut (Arachis hypogaea).

Two novel resistant QTLs mapped and candidate genes identified for Aspergillus flavus resistance in cultivated peanut using SLAF-seq. Aflatoxin contamination in peanuts caused by Aspergillus flavus is a serious food safety issue for human health around the world. Host plant resistance to fungal infection and reduction in aflatoxin are crucial for mitigating this problem. Identification of the resistance-linked markers can be used in marker-assisted breeding for varietal development. Here we report construction of two high-density genetic linkage maps with 1975 SNP loci and 5022 SNP loci, respectively. Two consistent quantitative trait loci (QTL) were identified as qRAF-3-1 and qRAF-14-1, which located on chromosomes A03 and B04, respectively. QTL qRAF-3-1 was mapped within 1.67cM and had more than 19% phenotypic variance explained (PVE), while qRAF-14-1 was located within 1.34cM with 5.15% PVE. While comparing with the reference genome, the mapped QTLs, qRAF-3-1 and qRAF-14-1, were located within a physical distance of 1.44 Megabase pair (Mbp) and 2.22 Mbp, harboring 67 and 137 genes, respectively. Among the identified candidate genes, six genes with the same function were found within both QTLs regions. In addition, putative disease resistance RPP13-like protein 1 (RPP13), lipoxygenase (Lox), WRKY transcription factor (WRKY) and cytochrome P450 71B34 genes were also identified. Using microarray analysis, genes responded to A. flavus infection included coding for RPP13, pentatricopeptide repeat-containing-like protein, and Lox which may be possible candidate genes for resistance to A. flavus. The QTLs and candidate genes will further facilitate marker development and validation of genes for deployment in the molecular breeding programs against A. flavus in peanuts.

English

Good agricultural practices are an effective means of minimizing pre-harvest aflatoxin contamination in peanuts. A field experiment was conducted to evaluate the effect of gypsum on pod yield and aflatoxin contamination in three peanut cultivars (Kadononga, MGV 4 and MGV 5) in Zambia. The experiment was conducted in Chongwe and Lusaka districts. Gypsum (15.6 % calcium) was applied at rates of 0 and 400 kg/ha at flowering stage. Although gypsum had no significant effect on aflatoxin contamination, there were significant differences (p = 0.009) in cultivar susceptibility to aflatoxin contamination. The cultivar with the smallest kernels had 18.8% lower aflatoxin content than the large-kernelled cultivar. Additionally, gypsum did not have a clear effect on pod yield. For instance, gypsum was associated with 44.8% more grain-filled pods in Kadononga (p = 0.005) at the site in Lusaka, but this result did not apply to the other two cultivars. At the site in Chongwe, gypsum was associated with 34.6% higher pod yield of MGV 5 only (p = 0.006). These results further suggest that plant factors such as kernel size may have an influence on natural resistance to aflatoxin contamination in peanuts. &nbsp; Key words: Aflatoxin, gypsum, peanut cultivar, pod-yield, Zambia.

Evaluating Improved Management Practices to Minimize Aflatoxin Contamination in the Field, During Drying, and in Storage in Ghana

ABSTRACT Aflatoxin in peanut ( Arachis hypogaea L.) and other crops can negatively affect human health, especially in countries where regulatory agencies do not have limits on aflatoxin entering the food supply chain. While considerable research has been conducted addressing aflatoxin contamination in peanut at individual steps in the supply chain, studies that quantify aflatoxin contamination following combinations of interventions of crop management, drying, and storage are limited. Research was conducted during 2016 and 2017 in two villages in southern Ghana to follow aflatoxin contamination along the supply chain and to compare improved practices with traditional farmer practices used by smallholders. The farmer practice of only a single weeding was compared with improved practices during the growing season up to harvest that included applying local soaps to suppress aphids ( Aphis gossypii Golver) that transmit peanut rosette virus disease ( Umbravirus: Tombusviridae e), one additional weeding, and calcium applied at pegging. The improved practice for drying included placing pods removed from plants onto tarps compared with the traditional practice of drying on the ground. Storing peanut for four months in hermetically-sealed bags was the improved practice compared with storing in traditional poly bags. All improved practices individually resulted in less aflatoxin contamination as compared to the farmer practices. While aflatoxin levels were found to be very low (&amp;lt;1 µg/g) at harvest, the levels increased significantly during drying and storage, with the improved methods resulting in lower levels. Greater estimated financial returns were noted when at least one improved practice along the supply chain was implemented through either increased yield or maintenance of quality kernels. Results from this research demonstrate progression of aflatoxin contamination at pre- and especially post-harvest in villages in Ghana. Future research needs to consider the effects of improved practices as components of packages that farmers can consider, and not just as individual interventions.