Fusarium head blight (FHB), caused by Gibberella zeae (Schw.) Petch, is a serious disease in many wheat (Triticum aestivum L.) growing regions worldwide. To study the inheritance of FHB resistance against fungal penetration (type I resistance), an Immortalized F2(IF) population containing 198 lines was constructed by crossing recombinant inbred lines chosen with random permutation of 132 RILs. The 132 RILs were chosen from the RIL population derived from the cross between FHB-susceptible cultivar Nanda 2419 and FHB-resistant cultivar Wangshuibai. The population was then evaluated for the percentage of infected spikes (PIS) across 2 years, and 6 chromosome regions were detected as being associated with type I resistance through interval mapping, among which Qfhi.nau-4B and Qfhi.nau-5A with the resistance alleles originating from Wangshuibai and Qfhi.nau-2B with the resistance allele from Nanda 2419 were consistently detected. Qfhi.nau-4B and Qfhi.nau-5A had the largest effects among the detected QTLs and for the most part, both showed additive allelic effects. The former was also partially dominant. In addition, 4 pairs of significant interaction loci were identified. These results demonstrated that wheat scab resistance was under complex genetic control and also implied that early generation selection for type I resistance in scab resistance breeding was feasible with Wangshuibai as the parent.
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