scholarly journals Genetic Variation and Aflatoxin Accumulation Resistance among 36 Maize Genotypes Evaluated in Ghana

2021 ◽  
Author(s):  
Abu Mustapha Dadzie ◽  
Allen Oppong ◽  
Ebenezer Obeng-Bio ◽  
Marilyn L. Warburton
Keyword(s):  
Aspergillus Flavus ◽  
Agronomic Traits ◽  
Local Strain ◽  
Genotype By Environment Interaction ◽  
Hplc Method ◽  
Aflatoxin Contamination ◽  
Environment Interaction ◽  
State University ◽  
Maize Genotypes ◽  
Aflatoxin Accumulation

Aflatoxins are carcinogenic secondary metabolites produced predominantly by the fungi Aspergillus flavus and parasiticus. The toxin contaminate maize grains and threatens human food safety. Survey in Ghana revealed aflatoxin contamination of maize in excess of 941 ppb which is way beyond WHO and USA approved limits of 15 ppb and 20 ppb respectively. Host plant resistance is considered as the best strategy for reducing aflatoxins. This study was designed to (1) identify and select suitable maize lines that combine aflatoxin accumulation resistance and good agronomic traits under tropical conditions and (2) assess the genetic diversity among the exotic and locally adapted maize genotypes using significant morphological traits. Thirty-six maize genotypes, 19 from Mississippi State University, USA and 17 locally adapted genotypes in Ghana were evaluated for aflatoxin accumulation resistance and good agronomic characteristics across six contrasting environments using a 6x6 lattice design with three replicates. Five plants each per genotype were inoculated with a local strain of Aspergillus flavus inoculum at a concentration of 9 x 107/3.4 ml, two weeks after 50% mid silking. Total aflatoxin in the kernels were determined at harvest using HPLC method. Statistical analysis for agronomic traits and aflatoxin levels were performed using PROC GLM procedure implemented in SAS. The result indicated that genotype by environment interaction was significant (p < 0.05) for aflatoxin accumulation resistance and many other agronomic traits. Five genotypes (MP715, NC298, MP705, MP719, CML287 and TZEEI- 24) consistently displayed stable resistance across the environments and may serve as suitable candidates for developing aflatoxin resistant hybrids. Cluster analysis showed two distinct groups (locally adapted and exotic genotypes), an indication of re-cycled alleles per region. Broad sense heritability estimates for grain yield and aflatoxin accumulation resistance were moderately high, which could permit transfer of traits during hybrid development.

Stability Analysis of Agronomic Traits for Maize (Zea Mays L.) Genotypes Based on Ammi Model

2021 ◽  
Vol 50 (2) ◽  
pp. 343-350
Author(s):  
Meijin Ye ◽  
Zhaoyang Chen ◽  
Bingbing Liu ◽  
Haiwang Yue
Keyword(s):  
Grain Yield ◽  
Agronomic Traits ◽  
Interaction Model ◽  
Genotype By Environment Interaction ◽  
Kernel Weight ◽  
Environment Interaction ◽  
Maize Hybrids ◽  
Genotype By Environment ◽  
Ammi Model ◽  
The Ideal

Stability and adaptability of promising maize hybrids in terms of three agronomic traits (grain yield, ear weight and 100-kernel weight) in multi-environments trials were evaluated. The analysis of AMMI model indicated that the all three agronomic traits showed highly significant differences (p < 0.01) on genotype, environment and genotype by environment interaction. Results showed that genotypes Hengyu321 (G9), Yufeng303 (G10) and Huanong138 (G3) were of higher stability on grain yield, ear weight and 100-kernel weight, respectively. Genotypes Hengyu1587 (G8) and Hengyu321 (G9) showed good performance in terms of grain yield, whereas Longping208 (G2) and Weike966 (G12) showed broad adaptability for ear weight. It was also found that the genotypes with better adaptability in terms of 100-kernel weight were Zhengdan958 (G5) and Weike966 (G12). The genotype and environment interaction model based on AMMI analysis indicated that Hengyu1587 and Hengyu321 were the ideal genotypes, due to extensive adaptability and high grain yield under both testing sites. Bangladesh J. Bot. 50(2): 343-350, 2021 (June)

Modelling the colonisation of maize by toxigenic and non-toxigenic Aspergillus flavus strains: implications for biological control

2008 ◽  
Vol 1 (3) ◽  
pp. 333-340 ◽  
Author(s):  
H. Abbas ◽  
R. Zablotowicz ◽  
H. Bruns
Keyword(s):  
Biological Control ◽  
Aspergillus Flavus ◽  
Growth Parameters ◽  
Biological Control Agent ◽  
Cyclopiazonic Acid ◽  
Aflatoxin Contamination ◽  
Tween 20 ◽  
Lag Phase ◽  
Gompertz Equation ◽  
Aflatoxin Accumulation

To successfully exploit biological control it is desirable to understand how the introduced agent colonises the host and interferes with establishment of the pest. This study assessed field colonisation of maize by Aspergillus flavus strains as biological control agents to reduce aflatoxin contamination. Maize (corn, Zea mays L.) ears were inoculated with A. flavus using a pin-bar technique in 2004 and 2005. Non-aflatoxigenic strains K49 (NRRL 30797) & CT3 (NRRL 30798) and toxigenic F3W4 (NRRL 30798) were compared against a carrier control (0.2% aqueous Tween 20). Ten ears were sampled over 12 to 20 days, visually assessed, and curves fit to a three compartment Gompertz equation or other best appropriate regressions. Aflatoxin was determined by HPLC and cyclopiazonic acid (CPA) by LC/MS. The Gompertz model describes growth parameters, e.g. growth constant, lag phase and maximum colonisation characterised patterns of maize colonisation for most inoculated treatments. Aflatoxin accumulation in maize inoculated with F3W4 was about 35,000 ng/g in 2004 and 2005, with kinetics of aflatoxin accumulation in 2005 well described by the Gompertz equation. Less than 200 ng/g was observed in maize inoculated with strains CT3 & K49 and accumulation was described by a linear or logistic model. Maize inoculated with strains CT3 and F3W4 accumulated a maximum of 220 and 169 µg/kg CPA, respectively, compared to 22 and 0.2 µg/kg in the control and K49 inoculated, respectively. This technique can be used to elucidate colonisation potential of non-toxigenic A. flavus in maize in relation to biological control of aflatoxin. The greatest reduction of aflatoxin and CPA in maize inoculated with strain K49 and Gompertz parameters on colonisation indicates its superiority to CT3 as a biological control agent. The dynamics of maize colonisation by A. flavus strains and subsequent mycotoxin accumulation generated by using the pin-bar technique has implications for characterising the competence of biocontrol strains for reducing aflatoxin contamination.

scholarly journals Interactions of Saprophytic Yeasts with anor Mutant of Aspergillus flavus

1999 ◽  
Vol 65 (6) ◽  
pp. 2738-2740 ◽  
Author(s):  
Sui-Sheng T. Hua ◽  
James L. Baker ◽  
Melanie Flores-Espiritu
Keyword(s):  
Aspergillus Flavus ◽  
Agar Plate ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
Orange Pigment ◽  
Yeast Strains ◽  
Norsolorinic Acid ◽  
Aflatoxin Accumulation ◽  
Food Commodities ◽  
Pigment Accumulation

ABSTRACT The nor mutant of Aspergillus flavus has a defective norsolorinic acid reductase, and thus the aflatoxin biosynthetic pathway is blocked, resulting in the accumulation of norsolorinic acid, a bright red-orange pigment. We developed a visual agar plate assay to monitor yeast strains for their ability to inhibit aflatoxin production by visually scoring the accumulation of this pigment of the nor mutant. We identified yeast strains that reduced the red-orange pigment accumulation in the normutant. These yeasts also reduced aflatoxin accumulation by a toxigenic strain of A. flavus. These yeasts may be useful for reducing aflatoxin contamination of food commodities.

scholarly journals Evaluation of Elite Maize Inbred Lines for Reduced Aspergillus flavus Infection, Aflatoxin Accumulation, and Agronomic Traits

Crop Science ◽  
2019 ◽  
Vol 59 (6) ◽  
pp. 2562-2571 ◽  
Author(s):  
Jacob J. Pekar ◽  
Seth C. Murray ◽  
Thomas S. Isakeit ◽  
Brian T. Scully ◽  
Baozhu Guo ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Agronomic Traits ◽  
Inbred Lines ◽  
Maize Inbred Lines ◽  
Aflatoxin Accumulation

scholarly journals Evaluation of Arachis Species and Interspecific Tetraploid Lines for Resistance to Aflatoxin Production by Aspergillus flavus

2004 ◽  
Vol 31 (2) ◽  
pp. 134-141 ◽  
Author(s):  
H. Q. Xue ◽  
T. G. Isleib ◽  
H. T. Stalker ◽  
G. A. Payne ◽  
G. OBrian
Keyword(s):  
Aspergillus Flavus ◽  
Insect Pests ◽  
Low Cost ◽  
Aflatoxin Production ◽  
Management Program ◽  
Aflatoxin Contamination ◽  
Sources Of Resistance ◽  
Resistant Parent ◽  
Arachis Species ◽  
Aflatoxin Accumulation

Abstract Anatoxins are carcinogenic and extremely toxic secondary metabolites produced primarily by two fungi, Aspergillus flavus Link ex Fries and A. parasiticus Speare. Elimination of aflatoxin contamination in peanut (Arachis hypogaea L.) is a high priority of the peanut industry. Resistant cultivars should be an effective and low-cost part of an integrated aflatoxin management program. To date, no cultivated peanut has been reported with stable high levels of resistance to aflatoxin production. Arachis species and interspecific tetraploid lines have been evaluated for resistance to several peanut diseases and insect pests, and highly resistant accessions have been reported. Seven accessions of A. cardenasii Krapov. and W.C. Gregory, 29 of A. duranensis Krapov. and W.C. Gregory, and 17 interspecific tetraploid lines derived from A. hypogaea × A. cardenasii were inoculated with A. flavus strain NRRL 3357 and analyzed for aflatoxin content after incubation. On average, A. duranensis and A. cardenasii accumulated significantly less aflatoxin than A. hypogaea checks. The mean difference between the two wild species was not significant. Arachis duranensis accessions PI 468319 (GKBSPSc 30073), PI 468200 (GKBSPSc 30064), and PI 262133 (GKP 10038 sl.); and A. cardenasii accessions PI 262141 (GKP 10017) and PI 475997 (KSSc 36018) had reduced levels of aflatoxin accumulation and should be valuable sources of resistance to aflatoxin contamination. Of the interspecific tetraploid lines, only GP-NC WS 2 supported aflatoxin production not significantly different from resistant parent A. cardenasii GKP 10017, and it appears to be a line with reduced capacity for aflatoxin accumulation.

Resistance to Aflatoxin Contamination in Corn as Influenced by Relative Humidity and Kernel Germination

1996 ◽  
Vol 59 (3) ◽  
pp. 276-281 ◽  
Author(s):  
B. Z. GUO ◽  
J. S. RUSSIN ◽  
R. L. BROWN ◽  
T. E. CLEVELAND ◽  
N. W. WIDSTROM
Keyword(s):  
Relative Humidity ◽  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Resistance Mechanisms ◽  
Aflatoxin Contamination ◽  
Aflatoxin Biosynthesis ◽  
Aflatoxin Accumulation ◽  
Moisture Conditions ◽  
Very High ◽  
Fungus Growth

Kernels of corn population GT-MAS:gk, resistant to aflatoxin B1 production by Aspergillus flavus, and susceptible Pioneer hybrid 3154 were tested for aflatoxin when incubated under different relative humidities (RH). High aflatoxin levels were not detected in either genotype at RH &lt; 91%. Resistance in GT-MAS:gk was consistent across all RH levels (91 to 100%) at which significant aflatoxin accumulation was detected. Aflatoxin levels in GT-MAS:gk averaged about 98% less than those in susceptible Pioneer 3154, which suggests that storage of this or other genotypes with similar resistance mechanisms may be possible under moisture conditions less exacting than are required with susceptible hybrids. Results for fungus growth and sporulation ratings on kernel surfaces were similar to those for aflatoxin levels. When kernels of both genotypes were preincubated 3 days at 100% RH prior to inoculation with A. flavus, germination percentages increased to very high levels compared to those of kernels that were not preincubated. In preincubated kernels aflatoxin levels remained consistently low in GT-MAS:gk but decreased markedly (61%) in Pioneer 3154. When eight susceptible hybrids were evaluated for aflatoxin accumulation in preincubated kernels, seven of these supported significantly lower toxin levels than kernels not subjected to preincubation. Average reduction across hybrids was 83%, and reductions within hybrids ranged from 68 to 96%. Preincubated kernels of one susceptible hybrid (Deltapine G-4666) supported aflatoxin levels comparable to those in resistant GT-MAS:gk. Data suggest that an inhibitor of aflatoxin biosynthesis may be induced during kernel germination. Possible mechanisms for embryo effects on resistance to aflatoxin accumulation are discussed.

scholarly journals Recurrent selection in inbred popcorn families

2004 ◽  
Vol 61 (6) ◽  
pp. 609-614 ◽  
Author(s):  
Máskio Daros ◽  
Antônio Teixeira do Amaral Jr. ◽  
Messias Gonzaga Pereira ◽  
Fabrício Santana Santos ◽  
Ana Paula Cândido Gabriel ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Recurrent Selection ◽  
Agronomic Traits ◽  
Block Design ◽  
Genotype By Environment Interaction ◽  
Small Scale ◽  
Environment Interaction ◽  
Genotype By Environment ◽  
Randomized Complete Block Design ◽  
Superior Genotypes

Although much appreciated in Brazil, commercial popcorn is currently cropped on a fairly small scale. A number of problems need to be solved to increase production, notably the obtaintion of seeds with good agronomic traits and good culinary characteristics. With the objective of developing superior genotypes in popcorn, a second cycle of intrapopulation recurrent selection based on inbred S1 families was carried out. From the first cycle of selection over the UNB-2U population, 222 S1 families were obtained, which were then divided into six sets and evaluated in a randomized complete block design with two replications within the sets. Experiments were carried out in two Brazilian localities. The analysis of variance revealed environmental effects for all evaluated traits, except popping and stand, showing that, for most traits, these environments affected genotype behavior in different ways. In addition, the set as source of variation was significant for most of the evaluated traits, indicating that dividing the families into sets was an efficient strategy. Genotype-by-environment interaction was detected for most traits, except popping expansion and stand. Differences among genotypes were also detected (1% F-test), making viable the proposition of using the genetic variability in the popcorn population as a basis for future recurrent selection cycles. Superior families were selected using the Smith and Hazel classic index, with predicted genetic gains of 17.8% for popping expansion and 26.95% for yield.

Assessing the representativeness and repeatability of testing sites for drought-tolerant maize in West Africa

2013 ◽  
Vol 93 (4) ◽  
pp. 699-714 ◽  
Author(s):  
B. Badu-Apraku ◽  
R. O. Akinwale ◽  
K. Obeng-antwi ◽  
A. Haruna ◽  
R. Kanton ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
West Africa ◽  
Genotype By Environment Interaction ◽  
Environment Interaction ◽  
Strongly Correlated ◽  
Maize Cultivars ◽  
Drought Tolerant ◽  
Maize Genotypes ◽  
Improvement Programme ◽  
Discriminating Ability

Badu-Apraku, B., Akinwale, R. O., Obeng-antwi, K., Haruna, A., Kanton, R., Usman, I., Ado, S. G., Coulibaly, N., Yallou, G. C. and Oyekunle, M. 2013. Assessing the representativeness and repeatability of testing sites for drought-tolerant maize in West Africa. Can. J. Plant Sci. 93: 699–714. The selection of suitable breeding and testing sites is crucial to the success of a maize (Zea mays L.) improvement programme. Twelve early-maturing maize cultivars were evaluated for 3 yr at 16 locations in West Africa to determine the representativeness, discriminating ability, and repeatability of the testing sites and to identify core testing sites. Genotype main effect plus genotype by environment interaction (GGE) biplot analysis revealed that Zaria (Nigeria), Nyankpala (Ghana), and Ejura (Ghana) displayed the highest discriminating ability. Two mega-environments were identified. Bagou, Nyankpala, Bagauda, Ikenne, and Mokwa constituted the first mega-environment (ME1); Ejura, Ina and Sotuba represented the second (ME2). The ME1 would be more useful for evaluating early maize genotypes for tolerance to drought than ME2 because locations in ME1 were more strongly correlated to Ikenne (managed drought stress site). Among the test locations, Bagou and Mokwa were found to be closely related to Ikenne in their ranking of the cultivars for drought tolerance; Zaria was the exact opposite, indicating that this was the least suitable location for evaluating genotypes for drought tolerance. Nyankpala and Ikenne were identified as the core testing sites for ME1 and Ejura for ME2. TZE Comp 3 C2F2 was identified as the highest yielding cultivar for ME1 and Syn DTE STR-Y for ME2, indicating that they could be used as check cultivars. Ikenne, Nyankpala, and Ejura had moderately high repeatability. They were closer to the average environment axis of each mega-environment and will be useful for culling unstable genotypes during multi-locational testing. Other sites were less representative and not repeatable and will not be useful for evaluating early maize cultivars for drought tolerance.

Production of the 14 kDa trypsin inhibitor protein is important for maize resistance against Aspergillus flavus infection/aflatoxin accumulation

2016 ◽  
Vol 9 (2) ◽  
pp. 215-228 ◽  
Author(s):  
Z.-Y. Chen ◽  
M.L. Warburton ◽  
L. Hawkins ◽  
Q. Wei ◽  
Y. Raruang ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Trypsin Inhibitor ◽  
Aflatoxin Production ◽  
Field Resistance ◽  
Aflatoxin Contamination ◽  
Direct Role ◽  
Independent Events ◽  
Sequence Polymorphisms ◽  
Transgenic Lines ◽  
Aflatoxin Accumulation

Maize (Zea mays L.) is one of the major crops susceptible to Aspergillus flavus Link ex. Fries infection and subsequent aflatoxin contamination. Previous studies found the production of an antifungal 14 kDa trypsin inhibitor (TI) was associated with maize aflatoxin resistance. To further investigate whether the TI plays any direct role in resistance, a TI gene silencing vector was constructed and transformed into maize. Mature kernels were produced from 66 transgenic lines representing 18 independent events. A final total of twelve lines representing four independent events were confirmed positive for transformation, five of which showed significant reduction (63 to 88%) in TI transcript abundance in seedling leaf tissue and seven of which showed significant TI protein reduction (39-85%) in mature kernels. Six of the seven silenced transgenic lines supported higher levels of aflatoxin production compared to negative controls. To further confirm the role of TI in field resistance to aflatoxin accumulation, DNA sequence polymorphisms from within the gene or linked simple sequence repeats were tested in four quantitative trait loci (QTL) mapping populations for QTL effect, and three QTL with log of the odds scores of 11, 4.5, and 3.0 and possibly caused by the TI protein encoding gene were found. Sequence polymorphisms were also tested for association to aflatoxin levels in an association mapping panel, and three single nucleotide polymorphisms were found associated with aflatoxin accumulation (P<0.01). The data from both RNAi and genetic mapping studies demonstrated that production of the TI in maize is important for its resistance to A. flavus infection and/or aflatoxin production.

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