A major falling number locus on chromosome 4B governs resistance to pre-harvest sprouting in bread wheat line Soru#1

Abstract Pre-harvest sprouting (PHS) is a serious threat to wheat quality and occurs when maturing seeds on plants encounter substantial rain before harvest. In the present study, the genetics of PHS resistance were studied using a population of 131 recombinant inbred lines (RILs) from a cross between Soru#1 and Naxos. The population was genotyped with the Illumina 90 K and Axiom 35 K wheat SNP arrays and tested in field trials across two locations in Norway and one in China. Seed dormancy as a measure of sprouting damage was evaluated using germination index (GI) and falling number (FN). Days to heading, days to maturity, and plant height were also recorded to evaluate their potential impact on PHS. Thirteen PHS-related quantitative trait loci (QTL) were detected. The most consistent QTL for FN, contributed by Soru#1, on the long arm of chromosome 4B explained 10.0–19.2% of the phenotypic variation across trials. Other important PHS resistance QTL from Soru#1 detected on chromosome arms 2AL, 2BL, and 4BS, affected both GI and FN. Naxos carried favorable QTL alleles for PHS resistance on chromosome arm 4AS and the Phs1 allele on 4AL. The reduced height Rht-D1 and vernalization Vrn-A1 alleles were the major determinants of plant height and earliness; however, these traits had minimal impact on the genetic control of PHS resistance in this population. Thus, both parents contributed valuable alleles for improving PHS resistance in breeding programs.