Gibberella ear rot (GER) of maize (Zea mays L.) caused by Fusarium graminearum Schwabe is a major disease in Europe that reduces grain yield and leads to contamination with deoxynivalenol (DON) and zearalenone (ZEA), two important mycotoxins. The objectives of our study were to (i) estimate quantitative‐genetic parameters for GER severity and DON and ZEA contaminations, (ii) map quantitative trait loci (QTL) for GER resistance and low DON and ZEA contaminations, and (iii) examine the prospects of marker‐assisted selection (MAS) for these traits. The materials comprised 150 doubled haploid lines from a cross of two maize inbreds that were evaluated in four environments under artificial inoculation with F. graminearum. On the basis of entry means across environments, heritabilities were moderately high (0.65–0.77), and QTL analyses identified four to six QTL for these traits. Colocalization of QTL in bins 1.11 and 2.04, which had large effects and together explained 29 to 35% of the total genotypic variance, suggested the presence of pleiotropic QTL. This was supported by strong genotypic correlations among these traits (0.89–0.95). In view of the lower costs of genotyping compared with field trials and mycotoxin determinations, our study showed that in breeding for GER resistance and low DON and ZEA contaminations, MAS should be conducted in off‐season nurseries and MAS in combination with phenotypic selection in the crop season.

Gibberella ear rot (GER) of maize (Zea mays L.) caused by Fusarium graminearum Schwabe leads to yield loss and contamination with deoxynivalenol (DON), the most commonly detected mycotoxin. To enhance the efficiency of marker-assisted selection (MAS), it is necessary to identify quantitative trait loci (QTL), which are effective across different genetic backgrounds. The objectives of the present study were to (i) map QTL for GER resistance and reduced DQN contamination, (ii) examine the congruency of QTL across four connected populations (three from this study and one from an earlier study), and (iii) draw conclusions about the prospects of MAS. The populations under study comprised doubled haploid (DH) lines derived from crosses of four flint inbreds. The traits were recorded under artificial inoculation. Estimates of genotypic variances (a,-) were significant and heritabilities were moderately high to high. We mapped QTL together explaining 21 to 49% of n," for GER severity and 19 to 30% for DON concentration. Colocalized QTL for GER resistance and reduced DON contamination were identified in each mapping population. Further, QTL located at similar positions were detected across three populations in two chromosomal regions and across two populations in additional two regions. The study indicated that a combination of classical phenotypic selection and MAS is a promising strategy to breed maize for GER resistance and reduced DON contamination.

Gibberella ear rot (GER) of maize caused by Fusarium graminearum leads to contamination of grains with mycotoxins such as deoxynivalenol (DON), thus reducing the quality of food and feed. A generation means analysis was conducted to estimate gene effects influencing the resistance to GER and DON contamination in flint maize germplasm adapted to Central Europe. Five crosses of two resistant and two susceptible flint inbred lines were developed, and each cross comprised both parent lines (P1, P2) as well as the F 1 and F 2 generation and the first backcross to both parents (BC 1 -P1, BC 1 -P2). All entries were grown in four environments and artificially inoculated with F. graminearum. There was a prevalence of additive gene action, while significant dominance effects were found in only one cross for resistance to GER, but in four crosses for resistance to DON contamination. Owing to the prevalence of additive gene action, the prospects are good to improve the resistance of the flint germplasm and to accumulate more favourable gene combinations in future breeding lines.

Gibberella ear rot (GER) of maize caused by Fusarium graminearum reduces grain yield and leads to contamination of the grains with deoxynivalenol (DON), a mycotoxin that adversely affects the health of humans and animals. The objectives of this study were to (1) analyze means and genotypic variances for line per se performance (LP) and testcross performance (TP) of doubled haploid (DH) lines for GER severity and DON concentration as well as for some agronomic traits, (2) examine correlations among these traits, (3) validate QTL for resistance detected in previous studies for LP and their effect on TP and (4) investigate the relative efficiency of indirect selection (RE) for LP to improve TP. Testcross progenies of 94 DH lines originating from four flint populations were developed using a susceptible dent tester as pollinator. Artificial inoculations with F. graminearum led to appreciable disease development. Average TP for GER severity and DON concentration were lower than the mean midparent values of the tester and DH lines, indicating mid-parent heterosis for resistance. Genotypic variation for resistance was significant for LP and TP. Genotypic correlations between LP and TP were low and resistance QTL for LP had no significant effects on TP. Accordingly, RE for resistance was low, suggesting to allocate resources mostly to the evaluation of testcrosses. Correlations of resistance to GER and DON contamination with grain yield (measured under non-inoculated conditions) were not significant, indicating that selection for resistance and higher grain yield can be carried out simultaneously.

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