Mapping quantitative trait loci for aflatoxin accumulation resistance in two populations containing resistant maize inbred Mp717

Abstract

Mp717, a maize germplasm line resistant to aflatoxin accumulation, served as the resistant parent in two bi‐parental quantitative trait loci (QTL) mapping populations: Mp717 × Va35 and Mp717 × PHW79. Both populations were phenotyped for concentration of total aflatoxins following artificial inoculation in replicated field trials grown in four environments. In all four environments in which the Mp717 × Va35 population was evaluated, the majority of the explained phenotypic variance was due to QTL for which the aflatoxin‐reducing allele was contributed by Va35, not Mp717. When the data were combined across environments, Mp717 contributed the beneficial allele for four QTL, but those QTL individually explained only 2.5 to 5.4% of the phenotypic variance. In contrast, Mp717 was the source of the resistance allele for the majority of the QTL observed in the Mp717 × PHW79 population in all four environments. When the data were combined across environments, Mp717 was the source of the resistance allele for eight QTL that individually explained 3.5 to 8.7% of the phenotypic variance. Three of those QTL individually explained 7.7 to 8.7% of the phenotypic variance, but none of those three QTL were observed in the Mp717 × Va35 population. Due to the small effect size of most observed QTL and the inconsistency across genetic backgrounds of the few medium‐effect QTL that were detected, it was concluded that no resistance QTL suitable for marker‐assisted introgression of the resistance present in Mp717 were detected in these two populations.

Efficiency of quantitative trait loci mapping under genotype x environment interaction

“…Quantitative trait loci mapping studies have been done for various crops and across environments but information on assessing the efficiency of QTL mapping under genotype by environment interaction remains scarce. Comparing the results obtained from this study and the results from some field investigations, we can confidently say that the data set used in this study depicts a real field data (Li et al, 2018;Xie et al, 2020;Smith et al, 2022). Interestingly, in the studies on rape seed by Xie et al, (2020), the authors recorded a positive correlation between some yield related traits and the environment which also agrees with the results from this study.…”

“…This result is also similar to the findings of Li et al (2018) in their study on maize using 204 recombinant inbred lines as they observed a positive correlation between some traits and the environment with heritability within the range of 30 to 87%. In another study by Smith et al (2022) on mapping aflatoxin content of maize, they recorded a correlation coefficient of -0.5 between environmental index and trait heritability. The values of heritability in their study was within the range of 43 to 63%.…”

Functional Study of Lipoxygenase-Mediated Resistance against Fusarium verticillioides and Aspergillus flavus Infection in Maize

“…Generally, commercial maize cultivars are susceptible to these pathogens, but several attempts to achieve maize lines with increased resistance to F. verticillioides [10,11] and A. flavus [11,12] have been reported in the literature. However, the resistance trait's complex genetic architecture, which is frequently associated with undesirable agronomic characteristics, has hampered its widespread adoption [13][14][15][16][17][18][19].…”