Assessing Genotype-By-Environment Interactions in Aspergillus Ear Rot and Pre-Harvest Aflatoxin Accumulation in Maize Inbred Lines

Abstract

Aspergillus flavus, causal agent of the Aspergillus ear rot (AER) of maize, also produces aflatoxins that cause aflatoxicosis in humans and livestock. Ten maize inbred lines were evaluated in replicated trials in two aflatoxicosis outbreak hot spots in Kenya and in three maize-growing areas in South Africa for resistance to AER, A. flavus colonization, and pre-harvest aflatoxin accumulation during the 2012/2013 growing season. AER severity was measured by visual assessment, while A. flavus colonization and aflatoxin content were quantified by real-time polymerase chain reaction (PCR) and liquid chromatography tandem mass spectrometry, respectively. Genotype by environment interaction (GEI) was determined using analysis of variance (ANOVA), additive main effects and multiplicative models (AMMI), and genotype plus by environment (GGE) biplot analyses. Stability of genotypes was evaluated using AMMI analysis. AER severity and fungal colonization significantly (p < 0.001) varied between genotypes. GEI influenced the severity of AER symptoms and aflatoxin accumulation significantly (p < 0.001), while fungal colonization was not affected. The inbred lines response was consistent for this trait in the test environments and was thus considered a desirable measure to indicate maize lines with a high risk of aflatoxin accumulation. CML495, CKL05019, LaPosta, and MIRTC5 were the least diseased lines, with the lowest aflatoxin contamination and a stable phenotypic response across the environments. Kiboko was determined as the ideal representative test environment, with discriminative ability of the genotypes for selection of the desired stable responses of the three traits.

Genotype by Environment Interaction Unravels Influence on Secondary Metabolite Quality in Cassava Infested by Bemisia tabaci

“…The genotypes exhibited consistent performance, stability and adaptability across the two seasons and three locations. The possibility of selecting genotypes that are stable within a wide range of environments is due to genomes rapidly responding by selectively regulating the expression of specific genes (Okoth, Rose, Sila, & Viljoen, 2017) in response to environmental changes (Hasanuzzaman et al, 2009). The results agree with Ballhorn et al (2011), where similar selections were made in lima bean studied for biochemical (protein, HCN) responses infested with bean beetle under altered abiotic factors.…”

Tolerance to Fusarium verticillioides infection and fumonisin accumulation in maize F1 hybrids and subsequent F2 populations

“…Six maize inbred lines (CML444, R119W, CKL05015, CML495, MIRTC5, and P502) previously characterized for their response to AER, FER, fumonisins and aflatoxins (Okoth et al, 2017a(Okoth et al, , 2017bOuko et al, 2018;Rose et al, 2016;Rose et al, 2017;Small et al, 2012) were used in this study. These germplasms originated from the International Maize and Wheat Improvement Center (CIMMYT) and Agricultural Research Council-Grain Crops Institute (ARC-GCI; Table 1).…”

“…Maize production is constrained by ear rot fungi belonging to the genera Aspergillus and Fusarium. Aspergillus flavus causes Aspergillus ear rot (AER) and contaminates maize grain with aflatoxins while infection of maize grain with F. verticillioides leads to Fusarium ear rot (FER) and fumonisin contamination (Ouko, Okoth, Amugune, & Vesa, 2018, Okoth et al, 2017a, 2017bRose et al, 2017). Infection of maize grain by F. verticillioides and subsequent contamination with fumonisins is influenced by climate, temperature, humidity, insect infestation, and pre-and postharvest handling (Fandohan, Gnonlonfin, Hell, Marasas, & Wingfield, 2005).…”

TRI Genotyping and Chemotyping: A Balance of Power

“…As such, on the basis of the proportion of potentially 'toxic' genotypes, it should be possible to predict whether there is a risk of toxin production and subsequent exposure [40]. A number of studies have utilized genotyping as a proxy to determining chemotype [41][42][43][44][45][46][47][48][49]. Table 3 outlines the various research efforts in applying TRI genotyping to Fusarium species over the last 20 years.…”