engleski

Diallel analysis of Fusarium head blight resistance caused by Fusarium graminearum in winter wheat

Fusarium head blight (FHB) caused by Fusarium spp. reduces grain yield and quality in wheat contaminating the infected grain with mycotoxins. Development of resistant wheat cultivars is believed to be the most efficient and economical mean of reducing damage caused by FHB. The FHB resistance in wheat is a quantitative trait, which can be evaluated using different measures based on visual disease symptoms or by measuring mycotoxin contamination of grain. In the present study we present the results of an F1 diallel analysis of FHB resistance involving eight European winter wheat genotypes and their F1 crosses. Parents and F1s excluding reciprocals were grown at location Zagreb over three consecutive years in a field trial arranged as a RCBD with two replications. Artificial inoculations with the isolate of F. graminearum Schwabe using spray method were performed at the beginning of anthesis and repeated on the same plots two days later. The resistance was scored visually 18, 22, 26 and 30 days after inoculation and expressed as % of wheat head area infected with FHB (VRI). After ripening 10 random spikes from each plot were manually harvested and % of fusarium damaged kernels (FDK) was assessed on threshed grains. In addition, milled samples of grain from each plot were used for quantitative analysis of mycotoxins deoxynivalenol (DON) and zearalenone (ZON) using an HPLC-MS/MS based-multianalyte method. For all traits both general combining ability (GCA) and specific combining ability (SCA) effects were statistically significant, whereas the interaction with year was significant only for GCA. Additive genetic variance accounted for 85, 76, 89 and 65% of the total genetic variance for VRI, FDK, DON and ZON, respectively. A high broad sense heritability was observed for analyzed traits ranging from 0.84 (ZON) to 0.92 (VRI) allowing for considerable progress by selection. A significant mid parent heterosis was observed in a number of F1 combinations for all traits, whereas a significant better parent heterosis was observed in several F1 crosses only for FDK and ZON content. Correlations between content of mycotoxins (DON and ZON) and disease ratings (VRI and FDK) were very strong ranging from 0.90 to 0.96 indicating that mycotoxin content in infected grain can be accurately predicted based on visual disease ratings.

fusarium graminearum ; winter wheat ; diallel analysis

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