Molecular mapping of kernel shattering and its association with Fusarium head blight resistance in a Sumai3 derived population.

Kernel shattering (KS) can cause severe grain yield loss in wheat (Triticum aestivum L.). The introduction of genotypes with Fusarium head blight (FHB) resistance has elevated the KS importance. 'Sumai3,' the most commonly used FHB-resistant germplasm worldwide, is reported to be KS susceptible. The objectives of this study were to detect quantitative trait loci (QTLs) for KS and to determine the relationship between KS and FHB. A recombinant inbred line population derived from a cross between Sumai3 and 'Stoa' was evaluated for KS in five environments and FHB in two field trials, separately. Four genomic regions on chromosomes 2B, 3B, and 7A were associated with KS. Of them, two major KS QTLs were detected consistently over three environments and each located proximal to the centromere on chromosomes 3B and 7A. The resistant alleles at these two QTLs together can reduce KS by 66.1% relative to the reciprocal alleles and by 41.1% compared to the population mean. The field FHB data revealed four QTLs on chromosomes 2B, 3B, and 7A. Three of these FHB QTLs coincided with and/or linked to the KS QTLs with opposite allele effects in the corresponding genomic regions, which may explain the negative correlation (r = -0.29 and P < 0.01) between the KS and FHB infection found in this study. The results in this study indicate that KS and FHB in Sumai3 are, in part, inherited dependently. However, the correlation between KS and FHB is not strong, and the major FHB resistance QTL on chromosome arm 3BS was not linked to any KS QTL. Our results showed that pyramiding of the two major KS-resistant alleles and the unlinked major FHB-resistant allele could produce lines with both low values of KS and FHB infection.