Dissection of genetic components of preharvest sprouting resistance in white wheat

Preharvest sprouting (PHS) in rain-affected wheat ( Triticum aestivum ) is a major constraint to the production of high-quality wheat, especially in regions where white grain wheat cultivars are preferred. To characterize quantitative trait loci (QTLs) for PHS resistance and seed dormancy (SD), we evaluated 162 recombinant inbred lines developed from the cross between PHS-resistant white wheat landrace Tutoumai A and PHS-susceptible white wheat cultivar ‘Siyang 936’ for PHS resistance and SD in field and greenhouse experiments. Composite interval mapping (CIM) identified four QTLs for PHS resistance and long SD that explained up to 45 and 40.8% of the phenotypic variation in five PHS and four SD experiments, respectively. Qphs.pseru - 4A.1 was detected in three of the five PHS experiments, and Qphs.pseru - 5B.1 , Qphs.pseru - 5B.2 , and Qphs.pseru - 4B.1 were detected in two of the five PHS experiments, respectively. All four QTLs for PHS resistance also affected SD. Qphs.pseru - 4A.1 was significant in all four SD experiments; the other three QTLs were detected only in one experiment. Additive and epistatic effects were observed for PHS resistance and SD. Besides three additive QTLs for PHS resistance and two for long SD, an additional 11 and 10 QTLs were detected with epistatic effects on PHS resistance and SD, respectively. The major genetic component of PHS resistance was SD, and other genetic factors may also contribute to PHS resistance in this population.