QTL mapping of preharvest sprouting resistance in bread wheat population SHA3/CBRD by Naxos confirms a negative effect of the 1BL.1RS translocation on falling number

Abstract

Preharvest sprouting (PHS) is a serious problem in wheat (Triticum aestivum L.) production areas with rainy harvest conditions. To explore the genetic control of PHS resistance, a population of 166 recombinant inbred lines from a cross between SHA3/CBRD and Naxos was evaluated in a total of eight field trials in Norway and China. PHS resistance was evaluated with both germination index (GI) and falling number (FN). A total of 15 PHS‐related quantitative trait loci (QTLs) were detected at chromosome arms 1RS, 2DL, 3BL, 4AL, 4BS, and 7BL. At 2DL and 3BL, QTLs for both GI and FN were detected in proximity to each other with PHS resistance from SHA3/CBRD, indicating a common genetic control of the two traits at these loci. At 4AL, a significant QTL for GI was detected with seed dormancy contributed by Naxos. Moreover, the Rht‐B1b dwarfing allele contributed by SHA3/CBRD showed a positive association with FN. On the other hand, QFN.nmbu‐1RS, carried by the 1BL.1RS translocation in SHA3/CBRD showed consistent negative effects on FN across all field trials where FN was measured. However, it did not have any notable effect on GI. The negative effect of QFN.nmbu‐1RS on FN was validated on a set of 113 wheat cultivars and breeding lines, where lines carrying the 1BL.1RS translocation showed significantly lower FN in 12 out of 14 independent field trials. The QTL and associated markers identified in this study will aid the breeding of more PHS‐resistant wheat cultivars.